Substrate-effect on the magnetic microstructure of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ thin films

Basic work principle and Applications of MEMS gyroscope(MEMS Angular Velocity Sensors)Aoyun ChenSchool of Electronic and Information Engineering, Soochow University ABSTRACTAs microelectronics is a well-developedtechnology, the research and development of MEMS isconcentrated on the research and development of micromechanical sensors and actuators, or micro mechanicaltransducers. A gyroscope is a sensor for measuringangular displacement. It is important for the attitudecontrol of a moving object. Their main applications arein the navigation systems of large vehicles, such asships, airplanes, spacecraft, etc.INTRODUCTIONGyroscopesThe critical part of a conventional gyroscope is a wheel spinning at a high speed. Therefore, conventional gyroscopes are accurate but bulky and very expensive. Their main applications are in the navigation systems of large vehicles, such as ships, airplanes, spacecraft, etc.In simplest terms, gyroscope is the sensor that measures the rate of rotation of anobject. The name “gyroscope” originated from L´eon Foucault, combining the Greek word “skopeein” meaning to see and the Greek word “gyros” meaning rotation, during his experiments to measure the rotation of the Earth.The earliest gyroscopes, such as the Sperry gyroscope, and many modern gyroscopes utilize a rotating momentum wheel attached to a gimbal structure. However, rotating wheel gyroscopes came with many disadvantages, primarily concerning bearing friction and wear. Vibrating gyroscopes, such as the Hemispherical Resonator Gyroscope (HRG) and Tuning-Fork Gyroscopes presented an effective solution to the bearing problems by eliminating rotating parts. Alternative high-performance technologies such as the Fiber-Optic Gyroscope(FOG) and Ring Laser Gyroscope (RLG) based on the Sagnac effect have also been developed. By eliminating virtually all mechanical limitations such as vibration and shock sensitivity and friction, these optical gyroscopes found many high-end applications despite their high costs.The MEMS TechnologyAs the name implies, Micro electro mechanical Systems (MEMS) is the technology that combines electrical and mechanical systems at a micro scale. Fig. 1One of the first examples of the gyrocompass, developed in the early 1800s. gyro compass gained popularity, especially in steel ships, since steel blocked the ability of magnetic compasses to find magnetic north.Practically, any device fabricated using photo-lithography based techniques with micrometer(1mm =106m) scale features that utilizes both electrical and mechanical functions could be considered MEMS. Evolved from the semiconductor fabrication technologies, the most striking feature of the MEMS technology is that it allows building moving micro-structures on a substrate. With this capability, extremely complex mechanical and electrical systems can be created. Masses, flexures, actuators, detectors, levers, linkages, gears, dampers, and many other functional building blocks can be combined to build complete sophisticated systems on a chip. Inertial sensors such as accelerometers and gyroscopes utilize this capability to its fullest. Photolithography based pattern transfer methods and successive patterning of thin structural layers adapted from standard IC fabrication processes are the enabling technologies behind micromachining. By dramatically miniaturizing and batch processing complete electro-mechanical systems, substantial reductions in device size, weight and cost are achieved.Fig. 2 A 150mm wafer from a gyroscope prototyping run. In a typical production process, it is common to have well over 2000devices on a 150mm wafer.Micromachined Vibratory Rate Gyroscopes Even though an extensive variety of micromachined gyroscope designs and operation principles exist, majority of the reported micromachined gyroscopes use vibrating mechanical elements to sense angular rate. The concept of utilizing vibrating elements to induce and detect Coriolis force presents many advantages by involving no rotating parts that require bearings and eliminating friction and wear. That is the primary reason why vibratory gyroscopes have been successfully miniaturized by theuse of micromachining processes, and have become an attractive alternative to their macro-scale counterparts. The fundamental operation principle of micromachined vibratory gyroscopes relies on the sinusoidal Coriolis force induced due to the combination of vibration of a proof-mass and an orthogonal angular-rate input. The proof mass is generally suspended above the substrate by a suspension system consisting of flexible beams. The overall dynamical system is typically a two degrees-of-freedom (2-DOF) mass-spring-damper system, where the rotation-induced Coriolis force causes.Applications of MEMS GyroscopesAs their performance keeps constantly improving in time, micromachined gyroscopes are becoming a viable alternative to expensive and bulky conventional inertial sensors. High-performance angular rate sensors such as precision fiber-optic gyroscopes, ring laser gyroscopes, and conventional rotating wheel gyroscopes are usually too expensive and too large for use in most emerging applications.With micromachining processes that allow batch production of micro-electro-mechanical systems on a chip similar to integrated circuits, unit costs unimaginable in any other technology are achieved. Moreover, advances in the fabrication techniques that allow electronics to be integrated on the same silicon chip together with the mechanical sensor elements provide an unmatched integration capability. Consequently, miniaturization of vibratory gyroscopes with innovative micro-fabrication processes and gyroscope designs is already becoming an attractive solution to current inertial sensing market needs, and even opening new market opportunities.With their dramatically reduced cost, size, and weight, MEMS gyroscopes potentially have a wide application spectrum in the aerospace industry, military, automotive and consumer electronics markets. The automotive industry applications are diverse, including advanced automotive safety systems such as electronic stability control (ESC), high performance Fig. 3 A packaged MEMS gyroscope chip. The threedimensional micro-scale structure is formed out of single-crystal silicon on a silicon substrate, complete with moving proof-masses, suspension beams, actuators and detectors.navigation and guidance systems, ride stabilization, roll-over detection and prevention, and next generation airbag and brake systems. A wide range of consumer electronics applications with very high volumes include image stabilization in digital cameras and camcorders, virtual reality products, inertial pointing devices, and computer gaming industry. Miniaturization of gyroscopes also enable higher-end applications including micro-satellites, microrobotics, and even implantable devices to cure vestibular disorders.Work principle of MEMS GyroscopeThe Coriolis EffectThe Coriolis effect, which defies common sense and intuition, has been observed but not fully understood for centuries. Found on many archaeological sites, the ancient toy spinning top (Figure 1.1) is an excellent example that the Coriolis effect was part of the daily life over three thousand years before Gaspard Gustave Coriolis first derived the mathematical expression of the Coriolis force in his paper “M´emoire sur les ´equations du mouvement relatif des syst´emes de corps” [1] investigating moving particles in rotating systems in 1835.The Coriolis effect arises from the fictitious Coriolis force, which appears to act on an object only when the motion is observed in a rotating non-inertial reference frame. The Foucault pendulum (Figure 1.2) demonstrates this phenomenon very well: When a swinging pendulum attached to a rotating platform such as earth is observed by a stationary observer in space, the pendulum oscillates along a constant straight line. However, an observer on earth observes that the line of oscillation processes. In the dynamics with respect to the rotating frame, the precession ofthependulum can only be explained by including the Coriolis force in the equations of motion.Coriolis force in linear vibratory rate gyroscope The most basic implementation for a micromachined vibratory rate gyroscope is a single proof mass suspended above the substrate. The proof mass is supported by anchored flexures, which serve asthe flexible suspension between the proof mass and the substrate, making the mass free to oscillate in two orthogonal directions - the drive and the sense directions (Figure 4a).The drive-mode oscillator is comprised of the proof-mass, the suspension system that allows the proof-mass to oscillate in the drive direction, and the drive-mode actuation and feedback electrodes. The proof-mass is driven into resonance in the drive direction by an external sinusoidal force at the drive-mode resonant frequency.The sense-mode accelerometer is formed by the proof-mass, the suspension system that allows the proof-mass to oscillate in the sense direction, and the sense-mode detection electrodes. When the gyroscope is subjected to an angular rotation, a sinusoidal Coriolis force at the frequency of drive-mode oscillation is induced in the sense direction.The Coriolis force excites the sense-mode accelerometer, causing the proof-mass to respond in the sense direction. This sinusoidal Coriolis response is picked up by the detection electrodes. For a generic z-Axis gyroscope, the proof mass is required to be free to oscillate in two orthogonal directions: the drive direction (x-Axis) to form the vibratory oscillator, and the sense direction (y-Axis) to form the Coriolis accelerometer. The overall dynamical system becomes simply a two degrees-of-freedom (2-DOF) massspring- damper system (Fig. 4b).a) b)Fig. 4a A generic MEMS implementation of a linear vibratory rate gyroscope. A proof-mass is suspended above a substrate using a suspension system comprised of flexible beams, anchored to the substrate. One set of electrodes is needed to excite the drive-mode oscillator, and another set of electrodes detects the sense-mode response. 4b A vibratory rate gyroscope is comprised of a proof mass which is free to oscillate in two principle orthogonal directions: drive and sense.a)b)Fig. 5a Torsional gyroscope by Bosch, with a drive mode about the z-Axis. SEM courtesy of Bosch. 5b simplified schematic of torsional gyroscopeCoriolis in torsional gyroscopeGimbals are commonly used in torsional gyroscope suspension systems to decouple the drive and sense modes, and to suppress undesired modes. Many suspension system and gimbal configurations are possible in torsional vibratory gyroscopes. Similar to linear gyroscope systems, the suspension system that supports the masses and gimbals usually consists of thin flexible beams, formed in the same structural layer as the proof-mass.An example gimbal system for a z-Axis torsional gyroscope based on [97] was shown in Figure 4.23. In the drive-mode, the outer drive gimbal is excited about the x-axis. In the presence of an angular rate input about z-axis, the sinusoidal Coriolis torque is induced about the y-axis, which causes the sense-mode response of the inner mass (Figure 5a).A representative gimbal implementation in y-Axis torsional gyroscopes based on [99] is presented in Figure 4.25. The system consists of an inner gimbal that can deflect torsionally in-plane about the z-Axis, and an the outer mass attached to the inner gimbal. The drive-mode is in-plane about the z-Axis, and the sensemode is out-of-plane about the x-Axis. In the drive-mode, the inner gimbal and the outer mass oscillate together, and the angular rate input about the y-Axis generates a Coriolis torque about the x-Axis. The outer mass responds to the Coriolis torque by deflecting torsionally about the x-Axis relative to the drive gimbal. The sensemode response is detected by the out-of-plane electrodes located underneath the outer mass structure.REFERENCES[1] P. M. Whelan, M. J. Hodgon, Essential Principles of Physics, J.W. Arrowsmith Ltd.Bristol, 1978[2] F. M. White, "Viscous Fluid Flow", McGraw-Hill Book Company, 1974[3] Analysis and Design Principles of MEMSDevices,Minghang Bao.。

Journal of Alloys and Compounds 509 (2011) 8475–8477Contents lists available at ScienceDirectJournal of Alloys andCompoundsj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /j a l l c omEffect of high intensity magnetic field on intermetallic compounds growth in SnBi/Cu microelectronic interconnectC.Z.Liu a ,∗,T.Y.Kang b ,W.Wei a ,K.Zheng a ,L.Fu a ,c ,L.Hui a ,J.J.Wang a ,W.P.Tong b ,∗∗aShenyang Aerospace University,Shenyang,110136,ChinabKey Laboratory of Electromagnetic Processing of Materials,Ministry of Education,Northeastern U niversity ,Shenyang,110819,China cState Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong University,Xi’an,Chinaa r t i c l ei n f oArticle history:Received 14October 2010Received in revised form 6June 2011Accepted 6June 2011Available online 12 June 2011Keywords:Diffusion KineticsInterconnect Magnetic fieldIntermetallic compoundsa b s t r a c tThe growth kinetics of intermetallic compounds (IMCs)(Cu 6Sn 5and Cu 3Sn)in eutectic Sn58wt.%Bi/Cu joints were studied,after they were aged at 85,100and 120◦C for different times in 0,12Tesla (T)magnetic fields,respectively.The Cu is believed to be dominant species,when Cu and Sn inter-diffuse to form IMCs in the interconnect.When the solder joints were aged in the magnetic field,magneticfield direction (denoted by magnetic flux density →B )was arranged to be parallel and anti-parallel as well as perpendicular to that of Cu diffusion.The results indicated that chemical compositions of the IMCs formed in magnetic fields were the same as those formed without magnetic field.The IMC growth rate in magnetic field was higher than that without magnetic field.And the activation energy for IMC growth in 12T magnetic field was 43.29kJ/mol,lower than 84.45kJ/mol for IMC growth without magnetic field.The accelerated IMC growth was independent of magnetic field direction.The phenomenon resulted from promoted interfacial reaction by magnetic field.© 2011 Elsevier B.V. All rights reserved.1.IntroductionLead-free solder eutectic SnBi alloy is of interest in electronic industry because of its advantages including low melting point (139◦C),excellent wetting performance and superior mechanical properties.Previous studies,such as literatures [1–5],have indi-cated that the IMC Cu 6Sn 5always forms (IMC Cu 3Sn also forms,however it is too thin to be found),after Sn-based solder/Cu joint is reflowed.The Cu 6Sn 5develops and Cu 3Sn can be found between Cu 6Sn 5and Cu substrate,when it is aged for long time.The mechan-ical properties always drop greatly due to the excessive growth of IMC layer [6,7].So the interfacial reaction kinetics between sol-der and Cu substrate is an important issue in reliability evaluation of electronic device.Many studies indicated that the average IMC thickness increased with the aging time,as described by Eq.(1).H =h 0+A 0exp−Q aRTtn(1)where h 0presents initial thickness of IMC in the joint,after the joint is reflowed;T ,temperature;t ,time;R ,constant;H is the average IMC thickness,after the interconnect is aged at T temperature for∗Corresponding author.Tel.:+862489724198.∗∗Corresponding author.Tel.:+862483682376.E-mail addresses:chunzliu@ (C.Z.Liu),wptong@ (W.P.Tong).time t .For most interconnects,the total IMC thickness values is a linear function of the √t.So n value in equation is 1/2,Q a value (activation energy)can be drawn from following Eq.(2):−Q a 2R =d[ln(d H/d t 1/2)]d(1/T )(2)With the development of new technology,many electronic devices have to work in the more complicated electromagnetic environment.Many papers [8–12]have showed that the high magnetic field can influence the metallurgical processes and signifi-cantly change the thermodynamic conditions of materials.Very few researches have been reported about the effect of magnetic field on the IMC growth in eutectic SnBi/Cu joint applied in electronic packaging.In this paper,a phenomenon of the IMC growth behav-ior in eutectic SnBi/Cu interconnect aged in high magnetic field is reported.This will be helpful to the design and choices of lead-free solder alloys for electronic devices in complicated electromagnetic condition.2.Experimental proceduresThe Cu sheets used in the study were pure,highly conductive and oxygen free.They were ground and polished with 0.5␮m diamond paste.The sandwich struc-tured Cu/Solder/Cu joint was prepared by placing commercial eutectic SnBi solder paste on one of two Cu sheets.Several shims were placed on the Cu sheet to con-trol the thickness of solder paste.Then two Cu sheets were aligned and clamped together.The reflow process was conducted at 170◦C for 5min to reflow the sol-der paste.The sample in this stage was in as-reflowed condition.Then it was cut into small pieces and aged in a special furnace.This furnace consists of a supercon-0925-8388/$–see front matter © 2011 Elsevier B.V. All rights reserved.doi:10.1016/j.jallcom.2011.06.0148476 C.Z.Liu et al./Journal of Alloys and Compounds 509 (2011) 8475–8477Fig.1.The schematic diagram of sandwich structured samples in the magnetic field (a);and the interfacial structures of eutectic SnBi/Cu interconnects in various conditions:as reflowed (b);aged at 120◦C for 70h,without magnetic field (c);aged at 120◦C for 70h,at interface I (d);aged at 120◦C for 70h,at interface II (e);aged at 120◦C for 70h,at interface III (f).ducting magnetic device (JMTD-12T 100,JASTEC,Japan)which can generates a highmagnetic field with maximum →B of 12T,and a vacuum resistance furnace.The spec-imens were aged at 85,100and 120◦C for 7,38and 70h in 0T and 12T magnetic fields,respectively.The specimens were also aged at 120◦C in 6T magnetic field for comparative purpose.When the specimens were aged in magnetic fields,they werearranged with their solder/Cu interfaces (I,II,III)perpendicular and parallel to the →B direction,as shown in Fig.1(a).The interfacial structures of these specimens were observed under JEOL JSN-7001F Scanning Electron Microscope (SEM).The chem-ical compositions of IMCs were analyzed by energy dispersive X-ray spectroscopy (EDS).The average thickness of the IMC layer was measured by using image analysis software Image pro plus 6.0.3.Results and discussionThe interfacial structures of the eutectic SnBi/Cu joints in dif-ferent conditions can be found in Fig.1(b)–(f).The IMC layer in as-reflowed condition,as shown in Fig.1(b),was identified to be Cu 6Sn 5by EDS and previous studies [3,6].And its thickness was about 1.31␮m.The solder alloy in the joint appeared to be eutec-tic lamella structure.Fig.1(c)indicated the interfacial structure of the joint aged at 120◦C for 70h without magnetic field.The grain size of the eutectic solder alloy developed after it was aged,com-pared with that of the solder in as-reflowed condition,as shown in Fig.1(b).The average thickness of Cu 6Sn 5grew from 1.31to 2.76␮m,and a new layer of Cu 3Sn identified by EDS and previous studies appeared between Cu 6Sn 5and Cu substrate.The interfacial structures of the interconnects aged at 120◦C for 70h in 12T mag-netic field can be found in Fig.1(d)–(f).The solder alloys aged in 12T magnetic field appeared the same structure as that aged without magnetic field,as shown in Fig.1(c).The IMC layer was composed of two sub-layers,Cu 6Sn 5and Cu 3Sn.The results demonstrated that chemical compositions of IMCs formed in interconnects aged in high magnetic field were the same as those aged without mag-netic field.The average thickness of IMC layer at interface I was 5.51␮m,while it was 5.53␮m at interface II and 5.83␮m at inter-face III,respectively,when they were aged at 120◦C for 70h in 12T high magnetic field.The magnetic field directions do not signifi-cantly influence the IMC thickness.The same situation occurred for all samples aged at 85and 100◦C in 6T and 12T magnetic fields.The relation curves between average thickness of the total IMC at three interfaces aged at 85,100and 120◦C in 0T and 12T magnetic fields and square root of aging time were presented in Fig.2.We can find that the average thickness of IMC in eutectic SnBi/Cu joints aged at 85,100and 120◦C in 0T and 12T magnetic fields increased linearly with the square root of aging time.The slopes of curves stand for the IMC growth rates.For the interconnects aged at 85,100and 120◦C in 12T magnetic field,the IMC growth rates were 0.275,0.361and 0.524␮m/h 1/2,respectively.They were greater than that of IMC formed at 85,100and 120◦C in 0T magnetic field,which were 0.048,0.083and 0.164␮m/h 1/2,respectively.The growth rate for IMC aged at 85◦C in 12T was 0.275␮m/h 1/2,greater than 0.164␮m/h 1/2,which was growth rate for IMC aged at 120◦C in 0T.The activation energies for them can be derived from these data by Eq.(2).They are 43.29kJ/mol and 84.45kJ/mol,respectively.These results demonstrated that the IMC growth in joints aged in 12T high magnetic field was accelerated.A part of the Cu 6Sn 5will turn into Cu 3Sn with Cu diffusion into Cu 6Sn 5,therefore the total IMC growth kinetics is the same as that of Cu 6Sn 5in the solder joint.The IMC growth kinetics for the joints aged at 120◦C in 0,6and 12T magnetic fields was presented in Fig.3.We can find that the IMC growth rate increased with the magnetic intensity increasing.They were 0.164,0.255and 0.524␮m/h 1/2,for total IMC aged at 120◦C in 0,6and 12T magnetic fields,while they were 0.071,0.084and 0.114␮m/h 1/2for IMC Cu 3Sn,which can be found in the inset of Fig.3.However,the IMC growth rate was not linear dependence of the intensity of the magnetic field (see Fig.4).Many studies [13–16]have revealed that Cu diffusion is domi-nant in the Sn/Cu inter-diffusion couple during the aging process.At interface I,the →B direction was reverse to that of Cudiffusion.Fig.2.The relation curves between average thickness of total IMC and square root of aging time t 1/2for joints aged at different temperatures in 12T and 0T magnetic fields.C.Z.Liu et al./Journal of Alloys and Compounds 509 (2011) 8475–84778477Fig.3.The relation curves between average thickness of total IMC and square root of aging time t 1/2for joints aged at 120◦C in 0,6and 12T magnetic fields.The inset is the kinetics for IMC Cu 3Sn in the joints aged at 120◦C in 0,6and 12T magnetic fields.At interface II,it was the same as Cu diffusion direction,while it was perpendicular to the Cu diffusion direction at interface III.The IMC thickness at three interfaces was nearly the same,when they were aged at the same temperature for the same time in themagnetic field.This indicated that the →B direction has no obvious influence on the Cu diffusion.Diffusion and interfacial chemical reaction are two processes for IMC formation and growth in the solder/Cu joint.And these two processes will mutually affect eachother.We have known that →B direction has no influence on Cu dif-fusion.Then,we can confirm that the interfacial reactions occurred at the interfaces in solder joints were enhanced by magnetic field.During aging process,at interface Cu 3Sn/Cu,Cu 3Sn/Cu 6Sn 5and Cu 6Sn 5/Solder,chemical reactions occur,respectively.The IMC for-mation process was discussed in detail in literature [13].Chemical reaction includes many processes,such as atoms activation process,meta-stable mid-reaction,etc.The rates of reactions do not entirely depend on the dynamic energy factors.They are also affected by the order of reaction system-entropy of the system [17].According to Lewis collision theory,the chemical reaction can occur,only when the atoms (or molecules)involving in reaction collide with each other in a proper direction.This kind of collision is effective.And the reaction rates are dependent on the number of effectivecol-Fig.4.The relation curve between total IMC growth rate in SnBi/Cu joint aged at 120◦C and intensity of the magnetic field.lision between them.The high magnetic field can affect unpaired electron spin of all the atoms (or molecule)involving in the reac-tion.We knew that Sn and Cu,which are main elements in the reaction under investigation,are paramagnetic and diamagnetic,respectively.When the joint was aged in high intensity magnetic field,the Cu and Sn atoms were forced to rotate to a direction and in which more Cu and Sn atoms can collide in a proper relative position to make the collision effective.So a part or all of chemi-cal reaction rates at the interfaces were accelerated in the solder joint by the magnetic field.And it was external high magnetic field that forced the Sn and Cu atoms involving in the reaction to rotate and collide effectively.When magnetic field direction changed,Cu and Sn atoms may rotate to other direction.But their proper rel-ative position in which they collide effectively was not changed.In other direction,they also can collide effectively.That is why we can find IMC growth rates at three interfaces were the same and all enhanced.The magnetic field affected the atom activa-tion process for chemical reaction.The accelerated reactions would consume more Cu atoms and decrease the Cu concentrations at interfaces,especially that at Cu 6Sn 5/solder interface.Then the Cu concentration gradient increases in IMC phases.The increased Cu concentration gradient would accelerate the Cu atoms diffusion to compensate the loss of Cu atoms due to more IMC formation.Con-sequently,the total IMC in high magnetic field grew faster than that did without magnetic field.4.ConclusionsIn summary,the IMC growth behavior in Sn58wt.%Bi/solder joint was examined,after it was aged at 85,100and 120◦C in 0T and 12T high magnetic fields.From the present study high magnetic fields can accelerate the growth rate of IMC Cu 6Sn 5and Cu 3Sn by promoting the interfacial reaction rates in the solder joint without influencing the chemical compositions of these IMCs.The activa-tion energy for IMC growth in eutectic SnBi/Cu interconnect aged in 12T magnetic field was 43.29kJ/mol,while it was 84.45kJ/mol for the joints aged without magnetic field.The accelerated IMC growth was independent of the magnetic field direction.AcknowledgmentsThis work is supported by the National Science Foundation of China (50871026),the 111Project (B07015),Foundation for the Author of National Excellent Doctoral Dissertation of PR China (200745),Program for New Century Excellent Talents in Univer-sity (NCET-06-0288),and the Fundamental Research Funds for the Central Universities (N090109001).References[1]K.N.Tu,K.Zeng,Mater.Sci.Eng.,R 34(2001)1.[2]Y.W.Wang,Y.W.Lin,C.R.Kao,J.Alloys Compd.493(2010)233.[3]E.Hodúlová,M.Palcut,E.Lechoviˇc ,B.ˇSimeková,K.Ulrich,J.Alloys Compd.509(2011)7052.[4]J.W.Yoon,B.I.Noh,B.K.Kim,C.C.Shur,S.B.Jung,J.Alloys Compd.486(2009)142.[5]C.C.Chang,Y.W.Lin,Y.W.Wang,C.R.Kao,J.Alloys Compd.492(2010)99.[6]C.Z.Liu,W.Zhang,M.L.Sui,J.K.Shang,Acta Metall.Sinica 41(2005)847.[7]T.Y.Kang,Y.Y.Xiu,C.Z.Liu,L.Hui,J.J.Wang,W.P.Tong,J.Alloys Compd.509(2011)1785.[8]X.Li,Z.M.Ren,Y.Fautrelle,Y.D.Zhang,C.Esling,Mater.Lett.64(2010)2597.[9]C.J.Li,H.Yang,Z.M.Ren,W.L.Ren,Y.Q.Wu,J.Alloys Compd.505(2010)108.[10]T.Liu,Q.Wang,A.Gao,H.Zhang,J.C.He,J.Alloys Compd.509(2011)5822.[11]X.Li,Y.Fautrelle,Z.M.Ren,Y.D.Zhang,C.Esling,Acta Mater.58(2010)2430.[12]W.P.Tong,H.Zhang,J.Sun,J.C.He,J.Mater.Res.25(2010)11.[13]K.N.Tu,R.D.Thompson,Acta Metall.30(1982)947.[14]C.Z.Liu,W.Zhang,J.Mater.Sci.44(2009)149.[15]P.T.Vianco,K.L.Erickson,P.L.Hopkins,J.Electron.Mater.23(1994)721.[16]C.K.Chung,J.G.Duh,C.R.Kao,Scripta Mater.63(2010)258.[17]J.Benting,New Scientist 24(1986)30.。

低RCS宽带磁电偶极子贴片天线设计张晨;曹祥玉;高军;李思佳;黄河【摘要】该文设计了一种低雷达散射截面(RCS)的宽带磁电偶极子贴片天线，其中印刷在介质板上的金属贴片为电偶极子，3个金属过孔连接辐射贴片与金属地板构成磁偶极子。

整个天线采用“T”型渐变馈电结构同时激励电偶极子与磁偶极子，天线的频带范围为7.81~13.65 GHz，覆盖了整个X波段。

实测和仿真结果表明，通过在磁电偶极子贴片天线底面采用开槽技术并优化开槽的形状、大小、位置等变量，在天线工作频带范围内实现了RCS的减缩，最大缩减量达到了17.9 dB，同时天线保持了增益稳定不变，E面、H面方向图一致的特性。

%A low Radar Cross Section (RCS) and broadband Magneto-Electric (ME) dipole patch antenna from 7.81 GHz to 13.65 GHz covering the whole X band is designed and fabricated. Metal patches printed on the substrate form the electric dipoles, three metallic vias connected to the radiation patches and the metal ground account for the magnetic dipole radiation. The whole antenna is connected with a T-shaped feed structure which excites electric and magnetic dipoles simultaneously. Numericaland experimental results incident that the RCS of the ME dipole patch antenna can be reduced inthe whole bandwidth which the largest value is up to 17.9 dB by cutting slots on the ground and optimizing the size, shape, position of the slots. Also, the antenna shows advanced performances such as stable gain and almost consistent pattern in E and H plane.【期刊名称】《电子与信息学报》【年(卷),期】2016(038)004【总页数】5页(P1012-1016)【关键词】磁电偶极子天线;宽频带;开槽技术;低RCS;一致性【作者】张晨;曹祥玉;高军;李思佳;黄河【作者单位】空军工程大学信息与导航学院西安 710077;空军工程大学信息与导航学院西安 710077;空军工程大学信息与导航学院西安 710077;空军工程大学信息与导航学院西安 710077;西安通信学院西安 710106【正文语种】中文【中图分类】TN821 引言微带贴片天线以其低剖面、易共形等优点在战场通信、监视及其它作战平台上得到了广泛应用，但由于带宽窄，不能用于宽频天线系统，且E面、H面方向图差异较大，不易于组成天线阵[1,2]。

第52卷第11期2023年11月人㊀工㊀晶㊀体㊀学㊀报JOURNAL OF SYNTHETIC CRYSTALSVol.52㊀No.11November,2023碳化硅晶圆的表面/亚表面损伤研究进展李国峰1,2,陈泓谕1,杭㊀伟1,韩学峰2,3,袁巨龙1,皮孝东2,3,杨德仁2,3,王㊀蓉2,3(1.浙江工业大学超精密加工研究中心,杭州㊀310023;2.浙江大学杭州国际科创中心,先进半导体研究院和浙江省宽禁带功率半导体材料与器件重点实验室,杭州㊀311200;3.浙江大学硅及先进半导体材料全国重点实验室&材料科学与工程学院,杭州㊀310027)摘要:表面无损伤㊁粗糙度低的半导体碳化硅(4H-SiC)衬底是制造电力电子器件和射频微波器件的理想衬底材料,在新能源㊁轨道交通㊁智能电网和5G通信等领域具有广阔的应用前景㊂4H-SiC衬底的加工过程包括切片㊁减薄㊁研磨㊁抛光和清洗,在4H-SiC衬底加工过程中引入的表面/亚表面损伤均严重影响材料性能㊁同质外延薄膜性质,以及器件性能和可靠性㊂本文将重点介绍4H-SiC晶片在切片㊁减薄㊁研磨㊁抛光等各个加工环节中表面/亚表面损伤的形成和去除机制,基于4H-SiC晶圆表面/亚表面损伤的检测方法,综述亚表面损伤的形貌和表征参量,并简单介绍三种常见的亚表面损伤的消除方法,分析其技术优势和发展瓶颈,对去除亚表面损伤工艺的发展趋势进行了展望㊂关键词:半导体;4H-SiC;衬底晶圆;表面/亚表面损伤;晶圆加工中图分类号:TQ163+.4;O786㊀㊀文献标志码:A㊀㊀文章编号:1000-985X(2023)11-1907-15 Research Progress on Surface/Subsurface Damages of4H Silicon Carbide WafersLI Guofeng1,2,CHEN Hongyu1,HANG Wei1,HAN Xuefeng2,3,YUAN Julong1,PI Xiaodong2,3,YANG Deren2,3,WANG Rong2,3(1.Ultra-precision Machining Research Center,Zhejiang University of Technology,Hangzhou310023,China;2.Institute of Advanced Semiconductors&Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices,Hangzhou Innovation Center,Zhejiang University,Hangzhou311200,China;3.State Key Laboratory of Silicon and AdvancedSemiconductor Materials&School of Materials Science and Engineering,Zhejiang University,Hangzhou310027,China) Abstract:4H silicon carbide(4H-SiC)substrate wafers without surface/subsurface damages and low surface roughness are ideal substrates for the development of power electronics and radio frequency(RF)microwave devices,which hold great promise in applications of new energy,rail transportation,smart grid and5G communication.The processing of4H-SiC substrate wafers includes slicing,grinding,lapping,polishing and cleaning.However,the surface damages(SDs)and subsurface damages(SSDs)introduced during the processing of4H-SiC substrates affects the properties of4H-SiC substrates and epitaxial layers,and thus the performance and reliability of devices based on4H-SiC.This paper focuses on the formation and removal mechanisms of SDs/SSDs during the processing of4H-SiC substrate wafers.Based on the detection method of SDs/SSDs,the morphologies and characterization approaches of SDs/SSDs are reviewed.Finally,three commonly used technologies for the removal SDs/SSDs,along with their technical advantages,development challenges and trends,are briefly discussed.Key words:semiconductor;4H-SiC;substrate wafer;surface/subsurface damage;wafer processing㊀㊀收稿日期:2023-05-28㊀㊀基金项目:国家自然科学基金(62274143,U22A2075,12204161,U20A20293);浙江省 尖兵 领雁 研发计划(2022C01021);国家重点研发计划(2018YFB2200101);中央高校基本科研经费(2018XZZX003-02);国家自然科学基金创新群体(61721005)㊀㊀作者简介:李国峰(1996 ),男,浙江省人,硕士研究生㊂E-mail:2112102259@㊀㊀通信作者:袁巨龙,博士,教授㊂E-mail:jlyuan@皮孝东,博士,教授㊂E-mail:xdpi@王㊀蓉,博士,研究员㊂E-mail:rong_wang@1908㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷0㊀引㊀㊀言4H碳化硅(4H-SiC)材料具有禁带宽度大㊁饱和电子漂移速率高㊁击穿电场高㊁导热系数高㊁抗辐照等优点,能够满足现代电力电子技术对高频㊁高功率㊁高温应用的要求[1]㊂而表面无损伤㊁低粗糙度的4H-SiC衬底晶圆是制造4H-SiC基电力电子器件的基础㊂由于材料的高硬度㊁强化学惰性等特点,4H-SiC的晶圆加工存在加工损耗大㊁损伤多㊁效率低等难题[2]㊂目前,4H-SiC晶圆的主要加工流程包括切片㊁减薄㊁研磨㊁抛光和清洗[3]㊂在晶圆加工过程中,减薄㊁研磨和抛光会依次去除切片引入的损伤层,实现晶圆的全局平坦化加工,得到无损伤㊁低表面粗糙度的4H-SiC晶圆㊂然而,4H-SiC晶圆的加工过程存在加工损伤去除不彻底或不可避免地引入新损伤的问题㊂根据损伤在光学显微镜检测下是否可见,4H-SiC晶圆表面的损伤分为表面损伤(surface damages,SDs)和亚表面损伤(subsurface damages,SSDs)㊂其中,SDs包括划痕㊁凸起㊁凹坑等,可通过光学显微镜直接观测;而SSDs主要分布于表面以下,无法通过光学显微镜直接观测㊂目前已发现的4H-SiC晶圆的SSDs包括:亚表面微裂纹㊁位错聚集㊁非晶相和残余应力等[4]㊂SDs/SSDs会在后续外延过程中作为缺陷的形核中心,严重影响外延层质量,进而影响4H-SiC基器件的性能与可靠性[5]㊂因此,准确识别SDs/SSDs,并阐明4H-SiC晶圆加工过程中SDs/SSDs的产生与去除机制,对于高质量4H-SiC晶圆的加工及应用至关重要㊂本文针对4H-SiC晶圆加工过程中产生的SDs/SSDs的形貌和来源进行分析,论述了在晶圆加工各个环节产生的SDs/SSDs的形成和去除机理,随后介绍了SSDs对后续外延和晶体生长的影响;最后简要介绍了SDs/SSDs的去除方法,比较去除效果,分析了其技术优势和发展瓶颈,并对其发展趋势进行展望㊂1㊀4H-SiC加工过程中的SDs/SSDs4H-SiC晶圆的主要加工流程分为切片㊁减薄㊁研磨㊁抛光和清洗㊂除了晶体本身的质量问题(如碳包裹㊁多型体㊁微管㊁位错等缺陷)[6],对衬底外延和后续器件制造影响最大的缺陷就是SDs/SSDs㊂由于二者均源于晶圆加工环节,因此明确SDs/SSDs的产生和去除机制,优化晶圆加工工艺,对严格控制4H-SiC晶圆的SDs/SSDs,并提升后续4H-SiC单晶生长或同质外延的质量具有重要意义㊂在4H-SiC的切片等加工工艺中,材料主要通过脆性断裂模式去除,这不可避免地会在表面下方引入微裂纹[7],造成材料的SDs和SSDs㊂亚表面的微裂纹不仅降低4H-SiC晶片的机械强度,还影响后续工艺和生产成本,是评价晶圆加工质量的一个重要指标㊂如图1(a)所示,切片工艺是影响切片过程中微裂纹损伤层厚度的关键因素㊂在后续减薄㊁研磨和抛光的加工过程中,损伤层的厚度逐渐减小,并在抛光后得到有效去除,获得全局平坦化的近无损4H-SiC晶圆㊂纳米压痕试验结果表明,4H-SiC在机械应力下产生的损伤层在宏观上呈现 Y 字形的裂纹,包括中位裂纹和侧位裂纹(见图1(b))[8]㊂其中,中位裂纹发生于磨料加载过程,随着磨料压入深度的增加,中位裂纹从变形区底端开始萌生,并向下扩展;当卸载时,中位裂纹逐渐闭合,侧位裂纹从变形区的底端开始萌生并向两侧和表面扩展,当侧位裂纹扩展到表面,形成表面破碎[2]㊂图1㊀4H-SiC衬底晶圆加工过程中SDs/SSDs的厚度变化(a)及裂纹产生的模型示意图(b)[8] Fig.1㊀Evolution of SDs/SSDs and change of the thickness(a),and diagram showing the generation mechanism ofcracks(b)in a4H-SiC substrate wafer[8]1.1㊀切片过程引入的损伤层作为4H-SiC晶圆加工过程的第一道工序,切片工艺质量决定了后续减薄㊁研磨㊁抛光的加工水平㊂切片㊀第11期李国峰等:碳化硅晶圆的表面/亚表面损伤研究进展1909㊀是影响晶圆损伤层厚度和面型参数的关键工艺㊂面型参数包括总厚度偏差(total thickness variation,TTV)㊁局域厚度变化(local thickness variation,LTV)㊁弯曲度(BOW)和翘曲度(WARP)㊂切片极易在4H-SiC晶片表面和亚表面产生大量裂纹和微裂纹,增加晶片的破片率和制造成本,因此控制晶片表层裂纹损伤对降低4H-SiC晶圆成本㊁推动4H-SiC基器件的发展具有重要意义㊂4H-SiC晶圆的切片方法有金刚线锯切片㊁游离砂浆线锯切片㊁激光切割和电火花切片等㊂其中,金刚线锯切片和游离砂浆线锯切片是目前4H-SiC晶圆加工最常用的切片方法,其原理是依靠金刚线或金属线带动砂浆使磨粒到达加工区域,并对磨粒施加压力,在磨料与晶锭表面接触瞬间,磨粒尖端会因冲击形成局域的微破碎,进而形成裂纹和材料脱落,以达到切片的目的[9]㊂该切割现象在单颗粒的游离砂浆线锯切实验中得到验证,但是划痕表面的材料剥落会使划痕的宽度超过磨料的直径[10],这与材料的去除方式有关㊂在晶圆加工过程中,材料的去除方式可分为脆性去除和延性去除[11]㊂由于4H-SiC具有高硬度㊁高脆性的特点,刀具刻划4H-SiC表面产生划痕的过程分为塑性阶段㊁塑脆性共存阶段和完全脆性阶段3个阶段,可以用摩擦力信号来表征[12]㊂图2所示为4H-SiC单晶的动载荷划痕实验,在塑性阶段主要以延性去除为主,摩擦力曲线光滑,划痕也以平滑凹槽为主;在塑脆性共存阶段,材料的去除既有延性去除又有脆性去除,划痕中显露出鱼鳞状凹坑;而在完全脆性阶段,脆性去除占主导,材料表面鱼鳞状凹坑进一步恶化并伴有裂纹萌生[13]㊂研究者们期望4H-SiC的材料去除机制更多表现为延性去除,以尽可能减小加工损伤和材料的损耗㊂然而,过分追求延性去除将会导致极低的材料去除率㊂因此,在脆性去除和延性去除两者间寻求一个平衡点是4H-SiC衬底加工的一个关键点㊂图2㊀4H-SiC晶圆动载荷划痕实验中划痕的摩擦力信号与载荷变化的关系(a)及划痕形貌变化图(b)[13] Fig.2㊀The dependence of the frictional force on the position(a),and the change of the scratch shape(b)during the dynamicload scratch experiment of a4H-SiC wafer[13]在4H-SiC线锯切片过程中,材料的脆性去除占据主导,导致4H-SiC在材料破碎去除的同时,产生大量的裂纹等损伤㊂随着钢线(或金刚线)深入材料内部,磨削力有所降低,4H-SiC材料的脆性去除进一步加剧㊂表1列出了金刚线锯切片和游离砂浆线锯切片两种切片方法的主要切削方式及其在4H-SiC中产生的损伤层的缺陷类型㊂在游离砂浆线锯切片时,4H-SiC亚表面会出现弥散的三角形损伤区,并带有半环束和堆垛层错;而金刚线锯切片会在4H-SiC晶片表面引入损伤区㊁半环束位错和堆积层错[14]㊂虽然由切片产生的SDs/SSDs是整个4H-SiC衬底加工中最严重的损伤,但通过优化切片工艺参数可以明显改善损伤层的厚度㊂如图3所示,通过优化线锯切工艺可显著控制4H-SiC的SDs/SSDs的厚度,其中减小晶体进给速度㊁增大线速度均有利于减小SDs/SSDs的厚度[15]㊂1910㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷表1㊀不同切片方法对4H-SiC加工造成的损伤[14]Table1㊀Damages caused by different sawing technologies of4H-SiC wafers[14]切片方法切削方式主要缺陷金刚线锯固定磨料平移损伤层半环束位错(U型30ʎ倾斜和V型)堆垛层错游离砂浆线锯游离磨料旋转三角形损伤区半环束位错(不倾斜U型)堆垛层错图3㊀金刚线锯切片4H-SiC晶圆过程中进给速度(a)和线速度(b)对微裂纹损伤的厚度影响[15] Fig.3㊀Effect of feed rate(a)and wire speed(b)on the thickness of microcrack damages during the diamond wiresawing of4H-SiC wafers[15]1.2㊀磨削过程引入的损伤层磨削的目的是去除4H-SiC切片过程引入的SDs/SSDs,同时降低晶圆的TTV㊁LTV和表面粗糙度[16]㊂由于4H-SiC的高硬度特性,磨削过程中必须使用高硬度的磨料(如金刚石[17])㊂磨削工艺一般包括减薄和研磨,分别对应于以固结磨料(砂轮)和游离磨料(研磨液)体系的磨削机制㊂固结磨料磨削具有材料去除速率高的优点,但是,砂轮磨削后,晶圆表面粗糙度较高,且SDs/SSDs层的厚度较大㊂为解决砂轮磨削后表面质量差的问题,学者们采用辅助增效[18],选用更合适的磨料比例和固结方式[19]等方法改善磨削4H-SiC晶片时的表面质量㊂研磨分粗磨和精磨,粗磨使用粒径较大的磨粒和铜盘,精磨使用粒径较小的磨料和锡盘[20]㊂虽然使用金刚石研磨液可以保证较好的晶体表面质量,但研磨效率低,研磨时间较长㊂4H-SiC磨削过程中SDs/SSDs主要包括凹坑㊁划痕㊁侧位裂纹和中位裂纹[21]等㊂在磨削过程中,与磨料接触的4H-SiC表面的晶相会向非晶结构转变[22],由于磨粒挤压在工件材料上,原有的晶格受到破坏,非晶相形成,在外力作用下,材料表面出现很多微断裂,进而实现材料去除[23-24]㊂非晶结构更容易被去除,这是因为此结构可以通过产生更小的法向应力和非晶态相变以及更薄的塑性变形诱导SiC软化并产生SSDs㊂这一发现与后续的单晶4H-SiC进行单颗粒磨削的模拟实验结果类似,即塑性变形初期的SSDs由非晶化和位错引发产生㊂随着磨削过程的进行,形成了滑移带,塑性变形后期滑移带的延伸是裂纹萌生的原因[25]㊂此外,分子动力学研究表明,非晶化是导致SDs产生的主要原因,而位错滑移则造成了SSDs的出现[26]㊂另一方面,当磨削过程中温度升高时,非晶层的润滑作用和表面的再结晶过程可以有效抑制高切削温度下的SSDs[27]㊂因此,通过工艺调试,探索总结出合适的磨削参数,确保较小的非晶层和高效的磨削效率是很有必要的㊂如图4所示,使用砂轮磨削4H-SiC晶圆时,单位切削进给深度的实际材料去除量和SSDs层的厚度不随磨削速度的增加而单调变化㊂其中存在材料去除量最大㊁SSDs层的厚度最小的最佳磨削速度㊂损伤层的厚度随磨削速度的增加而增大[28],这是因为在一定的磨削范围内,材料的去除主要以延性磨削为主,在晶圆表面,靠近晶圆中心位置磨削更加均匀,从而产生更高的表面质量[29];而当单位去除量超过一定范围,脆性去除模式会渐渐显露,这时横向裂纹开始萌生[21,30]㊂以此为基础,可以通过提高磨削速度和减小切削深度以提高材料的应变速率,从而以增强材料的动态脆性的方式降低SDs/SSDs[31]㊂除了磨削时的进给速率㊁砂轮转速等因素外,磨料的尺寸也是影响SSDs的关键因素之一㊂在砂轮磨削过程中,表面粗糙度和亚表面裂纹㊀第11期李国峰等:碳化硅晶圆的表面/亚表面损伤研究进展1911㊀深度随磨料颗粒粒径的减小而减小[32]㊂从砂轮磨削的单颗粒实验模拟中可以看到,裂纹从磨粒的前部和底部开始㊂随着磨粒不断向划痕方向移动,晶粒前部的裂纹通过研磨作用被去除,但晶粒下方的裂纹不能被去除,形成SDs /SSDs [33]㊂将微裂纹刻蚀暴露并与磨削参数对比发现,后者的变化趋势对微裂纹的影响和对表面粗糙度的影响是一致的㊂磨料的平均尺寸和磨削力对SSDs 和表面粗糙度的危害甚至大于砂轮速度和磨削的进给深度;而微裂纹的角度和密度几乎不受磨削参数的影响[34]㊂砂轮磨削工艺属于二体磨损加工㊂具体而言,磨削过程中固结在砂轮上的磨粒随着砂轮规则地往复运图4㊀砂轮磨削4H-SiC 过程中,切削速度对切削深度和SSDs 层的厚度的影响[28]Fig.4㊀Effect of cutting speed on the cutting depth and SSDs layer thickness during grinding of 4H-SiC [28]动,进而通过特定的轨迹摩擦晶圆表面,最终实现材料的去除㊂而使用研磨液的游离磨料研磨属于三体磨损加工,材料的去除伴随着磨料的随机滚动㊁挤压和刮擦三种状态㊂与二体磨损加工不同的是,三体磨损下磨料尺寸的不均匀可能会影响晶圆的表面加工质量[35]㊂在使用游离磨料研磨液研磨过程中,SDs /SSDs 层的厚度与磨粒的粒度㊁研磨盘的硬度成正比,而与研磨浆料的浓度成反比,并且与研磨压力和速度无关㊂同时,磨料尺寸对SDs /SSDs 层的厚度的影响比研磨盘硬度的影响更显著,而研磨浆料浓度的影响最小[36]㊂因此,相较于砂轮磨削,游离磨粒研磨的损伤更依赖于磨料尺寸㊂如图5所示,游离磨料加工后,晶圆的层错密度降低,且晶相显现非晶㊂同时,加工表面出现明显的晶格畸变现象,这是延性去除发挥优势的结果[37]㊂图5㊀砂轮磨削(a)~(c)和游离磨料研磨(d)~(f)4H-SiC 的Si 面的横截面TEM 照片[37]Fig.5㊀Cross-sectional TEM images of the Si surface of 4H-SiC by grinding (a)~(c)and lapping (d)~(f)[37]经砂轮磨削加工后,晶圆表面会产生螺旋式花纹状的表面划痕,而使用游离磨料研磨后,晶圆的表面划痕则是无序的㊂这种无序的表面划痕是由研磨液中磨料尺寸的不均匀性导致[38]㊂由于4H-SiC 材料具有各1912㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷向异性,C面的硬度大于Si面,在C面的脆性去除更明显㊂正是由于C面硬脆性较大,C面材料更容易产生微裂纹使材料剥落,因而C面的材料去除速率高于Si面[20],研磨后C面形成的SSDs的厚度大于Si面[35]㊂1.3㊀抛光过程引入的损伤层抛光工艺旨在进一步提高晶片的表面质量,改善表面粗糙度及平整度,使其表面质量特征参数符合后序加工中的精度要求㊂适合4H-SiC单晶片的精密抛光加工方法主要有机械抛光[39]㊁离子束抛光[40]㊁等离子体辅助抛光[41]和化学机械抛光(chemical mechanical polishing,CMP)[42]等㊂机械抛光以机械研磨为主,采用更小粒径的硬磨料对晶片表面进行延性去除,以去除研磨过程的残留应力层和机械损伤层,提高表面平面度及表面质量㊂离子束抛光技术是一种通过离子源发射离子束轰击光学零件表面产生物理溅射效应去除面形误差的新型抛光技术,近年来已逐渐应用于大口径光学元件的加工[43]㊂而CMP是目前实现4H-SiC晶片全局平坦化最有效的方法㊂4H-SiC衬底晶圆的CMP主要是在以氧化铝(Al2O3)㊁二氧化硅(SiO2)和二氧化铈(CeO2)等磨料,和以高锰酸钾(KMnO4)㊁双氧水(H2O2)等氧化剂共同组成的抛光液中,伴随氧化反应和机械去除同步进行,实现材料的去除和表面修整[44]㊂在CMP过程中,抛光浆料中的氧化剂首先氧化4H-SiC,在材料表面形成Si-C-O的过渡氧化态㊂氧化物的硬度低于4H-SiC,这确保了氧化物可以通过低硬度磨料的机械作用被去除,基于氧化和机械去除的循环实现了4H-SiC晶圆的CMP[45]㊂一般来说,CMP工艺可以在不造成SSDs的情况下加工全局平坦化的4H-SiC 衬底晶圆,且CMP处理后的SiC晶圆表面可以出现原子级台阶结构[46]㊂然而在实际生产加工中,由于操作不当或抛光耗材不合格等问题,经CMP后依旧发现衬底有局部损伤㊂在此条件下,重复CMP步骤时,可以看出残留划痕的位置发生了变化,这表明CMP本身是可能会产生细微划痕的[47]㊂CMP处理后残留的损伤有以下两种产生机制:1)在CMP之前引入的损伤,在CMP期间持续存在;2)在CMP期间引入的损伤[48]㊂在原子力显微镜(AFM)下,这些表面可以是无特征的或显示一些极小的抛光损伤㊂然而,在外延生长之前或期间经过高温热加工后,可以显示出密集的划痕和缺陷网络,该网络对应于机械磨损过程中冲击到4H-SiC 表面的SSDs或位错网络[49]㊂这些损伤有的来自于前道工序残留CMP没有完全去除的,而有的损伤则是由于CMP进行过程中,环境中的颗粒物等意外掉落于晶圆表面并参与抛光过程引起的划伤㊂因为这些纳米级划痕并不是均匀地引入到晶圆表面,而是非常局部地存在[42,50]㊂这些掉落物可能是大颗粒的二氧化硅,也有可能是4H-SiC晶圆的纳米级或亚微米级切屑㊂为了更好地解释CMP工序中意外引入损伤的产生机制,对比损伤形貌和在不同条件下获得的4H-SiC晶圆的位错结构,可以发现晶圆上的局部损伤是由CMP过程中施加的高局部应力造成的[51]㊂Tsukimoto等[52]通过高角度分辨电子背散射衍射(HR-EBSD)技术测量了4H-SiC晶片磨削损伤层的弹性应变分布来验证以上猜想㊂如图6所示,在晶圆加工位置的下方由于非常大的塑性应变会产生缺陷区域,通过研磨相互作用与相关的塑性变形和断裂不均匀地引入了晶格缺陷㊂基于这一机理,可以解释为在整个4H-SiC衬底的加工环节中,晶圆表面被施加高局部作用力而发生弹塑性变形是SSDs产生的最根本原因㊂图6㊀4H-SiC晶圆损伤层的高分辨TEM照片,显示微裂纹沿箭头所示路径从表面上的一点(X)向晶圆内部点(Y)扩展[52] Fig.6㊀The high-resolution TEM image of the damage layer showing the microcrack propagating from a point(X)on thesurface to an internal point(Y)along the path indicated by the arrow[52]㊀第11期李国峰等:碳化硅晶圆的表面/亚表面损伤研究进展1913㊀2㊀SDs /SSDs 的形貌和表征2.1㊀SDs /SSDs 形貌从线切到磨削㊁抛光,材料的SSDs 层的厚度会严重影响加工效率和下一步工序的移除量㊂因此,要想实现材料的高效低损伤加工,延长材料的使用寿命,降低后续工序的移除量,对材料的SSDs 层的厚度进行检测分析和预测十分必要[53]㊂如图7所示,SSDs 在晶圆表面仅呈现为划痕,但其纵向裂纹深度㊁具体结构等需要借助特殊手段来观测㊂脆性材料晶圆的SSDs 检测方法可分为有损检测和无损检测两类㊂其中,有损检测包括截面显微法[54]㊁角度抛光法[55]㊁化学刻蚀法[56]等㊂然而,它们在检测上都有一些瑕疵:前两者虽然可以直观看到SSDs 的形貌,但样本制作流程过于繁琐;化学刻蚀法操作方便,但刻蚀深度无法精准控制㊂无损检测方法包括声学显微镜[57]㊁拉曼光谱分析[55]㊁X 射线衍射[58]㊁共聚焦激光扫描法[59]㊁光致发光(PL)[60]等㊂这些方法同样适用于4H-SiC 晶圆的SSDs 的检测㊂图7㊀4H-SiC 晶圆在CMP 后残留划痕的光学显微镜(a)和SEM(b)照片[50]Fig.7㊀Optical microscopy (a)and SEM (b)images of the residual scratch of a 4H-SiC wafer after CMP [50]如图8所示,4H-SiC 的SDs /SSDs 主要成分是在切片㊁磨削和抛光过程中产生的断裂和划痕,而这些断裂和划痕会被抛光再沉积层部分或全部隐藏起来[61]㊂参考Si 的SSDs 模型可以发现,SSDs 主要可分为严重损伤部分和高应力弹性变形部分,其中严重损伤部分由微裂纹㊁非晶层㊁多晶层㊁位错等组成㊂而这两部分的比例由加工的参数和磨料的性质决定,且这两部分没有确切的边界,如图9所示[62]㊂随着加工的深入和磨料的尺寸降低,损伤逐渐降低至外延可接受范围,获得近无损的晶圆表面㊂图8㊀4H-SiC 晶圆抛光后的SSDs 分布的示意图[61]Fig.8㊀Schematic of SSDs after the polishing of 4H-SiC wafers [61]图9㊀Si 研磨后SSDs 的形貌和成分示意图[62]Fig.9㊀Schematic diagram of the morphology and composition of SSDs after the grinding of Si [62]图10所示为TEM 观察到的4H-SiC 衬底晶圆的SDs /SSDs 中位错层的微观形貌㊂可以看到局部损伤在垂直方向表现为划痕,两侧伴随有环形位错㊂经过衍射矢量和伯格斯矢量对比,确定该位错环为基平面位错(BPD)[50,63]㊂从这些位错环的形状推断,这些位错环主要是硅核心不全位错的滑移造成的[51,64]㊂同时,1914㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷BPD位错环的方向和局部损伤方向有关㊂4H-SiC衬底中的局部损伤会直接在外延层中反映出来,因此可以通过直接使用紫外灯照射外延晶圆使4H-SiC衬底中残留的BPD位错环在衬底中继承,并演化和延伸成肖克利型层错(Shockley-type stacking faults,SSF),如图11所示,外延层经UV处理后在PL中检测出半菱形结构[65]㊂对比发现,SSF的形貌又恰好可以和衬底中的BPD位错环对应㊂通过对半菱形SSF的方向统计后发现,虽然菱形大致分布于损伤的两侧,但不同晶向的损伤会使菱形的尖角方向分布出现偏差,这也可以说明衬底中不同晶向上的损伤,其BPD位错环的伯格斯矢量方向会有差异㊂图10㊀4H-SiC衬底中SSDs的表面TEM照片[50]Fig.10㊀Plane-view TEM image of SSDs of a4H-SiC substrate[50]图11㊀紫外光照射下4H-SiC外延薄膜中的Shockley型堆垛层错[65]Fig.11㊀Shockley-type stacking faults in4H-SiC epitaxial layer under UV irradiation[65]要观察SSDs的完整形貌,截面显微法是最直观的方法[66]㊂对4H-SiC损伤部分切片制样,在TEM中可看到损伤的完整纵向形貌,如图12所示[14]㊂损伤部分从上到下可分为覆盖层㊁亮层(损伤层)㊁半环形BPD 位错并伴随有SF㊂损伤层的形貌随划痕的晶向略有差异,但大致呈Y型,底部连接有层错,半环束从亮层向内扩散,形状为U型[61]㊂而在位错下方还有一层由于弹塑性变形而未被完全释放的应力层[62]㊂图12㊀4H-SiC衬底中的SSDs沿划痕方向(a)和垂直划痕方向(b)的缺陷分布示意图[14] Fig.12㊀Distribution diagram of SSDs parallel(a)and perpendicular(b)to the scratch of4H-SiC substrates[14]。

子技术分册部分单词子技术分册部分单词缩略词：BJT 双极结型晶体管 Bipolar Junction TransistorLED 发光二极管 Light Emitting DiodeMOS 金属氧化物半导体场效应晶体管 Metal Oxide SemiconductorFET 场效应晶体管 Filed Effect Transistorbcc 体心立方 Body-centered cubicfcc 面心立方 Face-centered cubicSOI Silicon-On-Insulator绝缘层上硅结构CVD Chemical Vapor Deposition化学气相淀积+ plus/positive - negative * minus / negativeX2 X square the square root of X3 x cube the cubic root of X y X to the yth单词：Semiconductor半导体transition 跃迁Conductivit电导率diffusivity piecewise 分段扩散率 resistivity 电阻率diffusivity 扩散系数Bipolar transistor 双极型晶体管 step junction 突变结Rectifie整流器 metallurgical junction 合金结Photodiode 光电二极管 fermi level 费米能级Leakage current 漏电流exponential 指数的Silicon dioxide 二氧化硅 dopant 掺杂Lattice 晶格dielectric 电解质 dislodge 移出Unit cell 晶胞 Facet 晶面bonding 键合phonon 声子Lattice constant 晶格常数 tetrahedral 四面体的 Diamond lattice 金刚石晶格Level energy 能级 Miller indices 弥勒指数 acoustic 声学的Hole 空穴lifetime 寿命Permittivity 介电常数continuity equation连续方程Covalent bonding 共价键 impurity 杂质Conduct/valence band 导带，价带device 装置，器件Effective density of states 有效态密度 magnetic 有磁性的Intrinsic 本征的 illumination 照明 silicon ，gallium，germanium，gallium arsenideExtrinsic 非本征的 reciprocal 倒数，相反的Carrier 载流子 agitation 激动，搅拌Bandgap 能带间隙 incremental 增加的Mass action law 质量作用定律excitation 激发Donor acceptor 施主受主Injection 注入collision 冲突，抵触impact ionization 碰撞电离superimposed 叠加sufficient 充分的Scatter 散射Drift 漂移 succession 连续的 drift velocity 漂移速度Mean free time /path 平均自由时间/程Mobility 迁移率saturation 饱和Recombination 复合 spatial 空间overwhelm vt.压倒；淹没；受打击 Decay 衰减Abrupt 突变 derivative 衍生物bias 偏见 gradient 梯度；magnitude 量级 Direct Recombination 直接复合Photoconductivity 光电导 potential barrier [物] 势垒；[电子] 位垒;voltmeter 电压计quantitative 定量的amplification 放大（率steady state 恒稳态;transient state 瞬态；过渡状态; qualitative .定性的rectification n. [电] 整流 equilibrium condition 平衡态endeavor 努力 conceive 设想；考虑 ; postulate.假定 unfolding 演变; Prime n. 初期； Primitive 原始的，简单的，粗糙的; artistic adj. 艺术的；supervisor n. 监督人，管理人；检查员;Instinct n. 本能，直觉 analog n.模拟；类似物analytical adj. 分析的 genuine adj. 真实的，真正的 inferior n. 下级；次品 acronym n. 首字母缩略词; insofar as 在…的范围内；到…程度; embodimentn. 体现；化身；具体化 ;proliferate vi. 增殖；扩散；激增vt.使激增;constantly adv. 不断地；时常地; complementary adj. 补足的，补充的; dissipation n.浪费；消散；[物] 损耗; vehicle n. [车辆] 车辆；工具；交通工具；传播媒介Parallelepiped n. 平行六面体; metallurgical adj. 冶金的；冶金学的; Pedestal n. 基架，基座； analogous adj. 类似的；可比拟的; Ambiguity n.含糊；不明确； retain vt.保持；雇；记住; Resemblance n. 相似；相似之处prototypical adj. 原型的；典型的; Parasitic adj. 寄生的（等于parasitical）;Vestigial adj. 退化的；残余的；发育不全的;parallel n. 平行线平行的 Grooves n. 细槽，凹槽simultaneously同时发生地 remnant n. 剩余adj. 剩余的;Mount n. 山峰；底座； Acknowledge 承认; disturbance 干扰; inevitable 不可避免的;inherent 固有的; subsume 把。

第41卷第3期2022年3月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.41㊀No.3March,2022VTD 法制备不同基底倾角的硒化锑薄膜及太阳电池白晓彤1,2,崔晓荣1,2,张林睿1,2,周炳卿1,2(1.内蒙古师范大学物理与电子信息学院,呼和浩特㊀010022;2.内蒙古自治区功能材料物理与化学重点实验室,呼和浩特㊀010022)摘要:硒化锑(Sb 2Se 3)具有较高丰度及良好的光电特性,是当前热门太阳电池材料之一㊂目前,在Sb 2Se 3的多种制备方法中,气相转移沉积法(VTD)因工艺简单且可大面积制备而备受关注㊂采用VTD 法制备Sb 2Se 3薄膜的影响因素有多种,如腔体气压㊁反应温度㊁蒸发源与衬底的位置以及生长角度等㊂本文利用VTD 法以不同的生长角度(30ʎ㊁45ʎ㊁60ʎ㊁90ʎ)制备了Sb 2Se 3薄膜,对其进行XRD㊁Raman㊁SEM㊁近红外-紫外反射表征㊂结果表明不同生长角度对薄膜的结构以及光学特性具有明显的影响㊂晶粒尺寸随着生长角度的增加而先增大后减小,同时薄膜的形貌由棒状生长转变为片状生长,在基底倾角为90ʎ时,薄膜变得最为致密㊂近红外-紫外反射光谱表明倾角60ʎ的样品在波长小于1100nm 的范围具有最低的反射率,在该角度下制备的FTO /CdS /Sb 2Se 3/C 器件获得了2.38%的转换效率㊂关键词:硒化锑;气相转移沉积法;基底倾角;太阳电池;微结构;带隙中图分类号:O47㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2022)03-1063-06Preparation of Sb 2Se 3Film and Solar Cells with Different Substrate Inclination by VTD MethodBAI Xiaotong 1,2,CUI Xiaorong 1,2,ZHANG Linrui 1,2,ZHOU Bingqing 1,2(1.College of Physics and Elecrtonic Information,Inner Mongolia Normal University,Hohhot 010022,China;2.Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials,Hohhot 010022,China)Abstract :Antimony selenide (Sb 2Se 3)has become one of the most popular solar cell materials because of its high abundance and good photoelectric properties.At present,among many preparation methods of Sb 2Se 3,vapor transfer deposition (VTD)has attracted much attention because of its simple process and large area preparation.There are many factors affecting the preparation of Sb 2Se 3films by VTD,such as chamber pressure,reaction temperature,the position of evaporation source and substrate,substrate inclination and so on.Sb 2Se 3thin films were prepared by VTD at different substrate inclinations (30ʎ,45ʎ,60ʎ,90ʎ)and characterized by XRD,Raman,SEM and near infrared-ultraviolet (NI-UV)reflection.The results show that different substrate inclinations have obvious effects on the structure and optical properties of the films.The grain size first increases and then decreases with the increase of substrate inclination.At the same time,the morphology of the film changes from rod to sheet.When the substrate inclination is 90ʎ,the film becomes dense.The NI-UV reflection spectrum shows that the sample with an inclination of 60ʎ,has the lowest reflectivity in the range ofwavelength less than 1100nm.The FTO /CdS /Sb 2Se 3/C device prepared at this angle has a conversion efficiency of 2.38%.Key words :Sb 2Se 3;vapor transfer deposition;substrate inclination;solar cell;microstructure;band gap 收稿日期:2021-11-03;修订日期:2021-11-29基金项目:国家自然科学基金(51262022);内蒙古自治区自然科学基金博士基金(2020BS02011)作者简介:白晓彤(1995 ),女,硕士研究生㊂主要从事半导体薄膜太阳电池的研究㊂E-mail:347033811@通信作者:张林睿,博士,讲师㊂E-mail:20190039@周炳卿,博士,教授㊂E-mail:zhoubq@0㊀引㊀言社会的高速发展使人们面临着环境污染和能源短缺两大难题,因而对于可持续㊁可再生且低成本的能源1064㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷需求一直是各国关注的重点㊂风能㊁水能㊁太阳能等新能源可有效应对这些问题,其中太阳能作为绿色清洁能源备受人们青睐㊂太阳电池是获取太阳能的一种有效手段,对于太阳电池而言,一般以高效率㊁低成本以及长期稳定性为发展指标,其中以高效率为发展前提㊂目前,晶硅太阳电池因其高效率和良好的稳定性在光伏领域占据主导地位,而当前新型太阳电池的研究主要围绕着柔性㊁廉价以及低毒三方面展开㊂近年来,Sb2Se3由于无毒性,且锑和硒的元素含量丰富,成为一种很有前途的薄膜光伏太阳电池材料㊂迄今为止,已经开发了各种加工方法如真空法和非真空法来制备Sb2Se3吸收层,真空法包括蒸发法和溅射法等,其中蒸发法制备薄膜的技术有热蒸发法(thermal evaporation,TE)[1-2]㊁快速热蒸发法(rapid thermal evaporation,RTE)[3]㊁近空间升华(closed space sublime,CSS)[4]㊁气相转移沉积法(vapor transfer deposition, VTD)[5]㊁脉冲激光沉积(pulse laser deposition,PLD)[6-7]等,而非真空法主要有前驱体溶液法[8]㊁电沉积法[9-10]等㊂Sb2Se3是一种简单二元相化合物且具有一些理想的光电特性,例如1.1~1.3eV的带隙,超过105cm的高吸光系数,化学性质稳定,载流子寿命长等㊂除此之外,Sb2Se3还具有高的蒸气压(550ħ时约1200Pa),这一优势使得低成本的VTD法得以成功使用㊂一般认为,影响VTD法成膜质量的主要因素有蒸发源温度和基底温度㊁腔体气压㊁蒸发源与基底之间的距离㊁基底倾角㊁沉积时间等㊂本文利用VTD法制备Sb2Se3薄膜,重点研究了不同基底倾角(即30ʎ㊁45ʎ㊁60ʎ㊁90ʎ)对Sb2Se3薄膜的结构与光学特性的影响,并利用在不同角度下生长的Sb2Se3薄膜制备成太阳电池,对其进行一系列表征分析㊂1㊀实㊀验1.1㊀衬底表面预处理对尺寸为20mmˑ20mmˑ2.2mm的掺F的SnO2(FTO)导电玻璃进行表面清洗:依次使用FTO清洗剂㊁丙酮溶液㊁无水乙醇溶液以及去离子水对衬底进行超声波清洗20min,最后将清洗后的FTO导电玻璃放进密封的干燥箱中烘干备用㊂1.2㊀缓冲层的制备化学水浴法(chemical bath deposition,CBD)沉积CdS用作电子缓冲层,硫脲(0.1g)作为实验的硫源,硫酸镉(0.0768g)为镉源,以去离子水(250mL)为溶剂进行反应溶液的制备,再在其中加入16mL的氨水溶液充分混合㊂将干燥箱中清洗好的FTO导电玻璃浸没于均匀的反应溶液中,随后将配置好的反应溶液放至温度为65ħ的恒温水浴锅中,将转速调至为20r/min,充分反应23min㊂最后用去离子水将所得的CdS 薄膜表面残余的大颗粒冲洗干净并干燥备用㊂1.3㊀吸收层的制备本实验采用的VTD系统主体为双温区管式炉,由加热系统㊁石英管㊁机械泵和真空计组成㊂在实验过程中,称取两份0.2g的Sb2Se3粉末,倒入石英舟中并摇晃使其均匀分布,随后放在石英管底部㊂将镀有CdS 薄膜的FTO玻璃衬底放在一定倾角的石墨台上,拧紧真空法兰,抽真空至3Pa以下后开始加热㊂两个温区均加热至520ħ,保温3min后自然降温,当管内温度低于60ħ时关闭真空泵,并打开炉盖,待冷却至室温取出样品㊂1.4㊀电极的制备碳电极在作为电极的同时还可以充当太阳电池的空穴传输层,因而采用丝网印刷技术制备碳电极㊂在本实验中,使用普通的导电碳浆通过丝网印刷工艺涂抹至Sb2Se3薄膜表面,随后放入70ħ的真空干燥箱中60min㊂1.5㊀仪器表征薄膜样品的晶体结构由X射线衍射(XRD)分析仪(PW1830)测定,测定范围设置为10ʎ~70ʎ;利用拉曼(Raman)光谱仪(型号:HORIBA Scientific HR Evo Nano)进一步分析薄膜的物相结构及样品的相纯度;利用近红外-紫外可见光谱分析仪(型号:Perkin Elmer1502r32s)对薄膜的反射光谱进行测试,并根据Kubelka-Munk转换公式得到各薄膜样品的带隙值;利用扫描电子显微镜(型号:HITACHI SU8220)对薄膜的表面形貌进行测定;利用Keithley2400数字源表和AAA级太阳光模拟器(型号:XFS-70S1)获得I-V特性曲线,从而获得太阳电池的各项电池特性㊂第3期白晓彤等:VTD 法制备不同基底倾角的硒化锑薄膜及太阳电池1065㊀2㊀结果与讨论2.1㊀物相分析对材料进行X 射线衍射测试用于确定薄膜的晶体结构㊂图1为在不同基底倾角下制备的Sb 2Se 3薄膜XRD 谱㊂由图可知,不同基底倾角的样品在XRD 谱中出现了较为明显的Sb 2Se 3特征峰(JCPDS 00-089-0821),Sb 2Se 3的三强峰发生在2θ为28.2ʎ㊁31.2ʎ以及32.2ʎ处,其分别对应Sb 2Se 3的三个晶面(221)㊁(211)及(301)㊂同时可以看到,随着生长角的增大,(211)和(221)晶面的峰值强度呈先增强后减弱的趋势㊂当基底倾角为30ʎ时,薄膜是以(120)取向生长㊂随着倾角的增大,Sb 2Se 3薄膜的(211)和(221)晶面都呈先增强后减弱的趋势,其中(221)晶面衍射峰变化最为明显,该现象表明Sb 2Se 3薄膜由(120)取向转为(221)取向生长㊂有研究表明:(221)晶面生长反映着[Sb 4Se 6]n 带斜立于基底上,其对载流子传输有利;如果(120)为择优取向,[Sb 4Se 6]n 带平行于基底上,且载流子主要在带间传输,该现象将影响载流子传输[11]㊂因而,从图中可知以基底倾角为60ʎ制备薄膜,更适合于后续电池的制备㊂通过Scherrer 公式,计算了基底倾角为30ʎ㊁45ʎ㊁60ʎ和90ʎ的薄膜在(221)㊁(211)和(301)三个晶面上的平均晶粒尺寸,分别为22.29nm㊁36.25nm㊁41.87nm 和38.05nm,从计算结果可得出随着倾角的增大,晶粒尺寸先增大后减小㊂当基底倾角为60ʎ时Sb 2Se 3薄膜晶粒尺寸最大,结晶性最佳㊂Raman 光谱与XRD 谱相结合,可以进一步分析薄膜表层的物相结构,因此对相关样品进行了Raman 光谱测试㊂图2给出了Sb 2Se 3薄膜在不同生长角度下的Raman 散射光谱,利用532nm 激光器作为激发源㊂由图可知,Raman 光谱的振动中心都在波数为182cm -1以及247cm -1位置附近,该峰为Sb 2Se 3的Raman 特征峰,分别表示Sb 2Se 3的Sb Se 极性振动和Sb Sb 非极性振动㊂此外对于倾角为60ʎ的Sb 2Se 3样品在波数为351cm -1和446cm -1位置附近还观察到两个较明显的Raman 振动峰,为Sb 2O 3的特征峰[12]㊂由XRD 测试结果计算可知,基底倾角为60ʎ制备的薄膜晶粒尺寸较大,在空气中滞留后,较大的晶粒更容易吸附氧导致薄膜样品被氧化,因此出现了少量的Sb 2O 3㊂尽管如此,Sb 2Se 3两处特征峰的最高峰值仍为在基底倾角为60ʎ下生长的薄膜样品,表明此角度生长的薄膜结晶性最好,且与XRD 结果相符㊂图1㊀不同基底倾角的Sb 2Se 3薄膜XRD 谱Fig.1㊀XRD patterns of Sb 2Se 3films with different substrateinclination 图2㊀不同基底倾角的Sb 2Se 3薄膜Raman 光谱Fig.2㊀Raman spectra of Sb 2Se 3films with different substrate inclination2.2㊀SEM 形貌分析为了进一步分析薄膜的结构变化,采用扫描电子显微镜(SEM)对薄膜样品的表面形貌进行测定㊂图3(a)㊁(b)㊁(c)㊁(d)分别对应基底倾角为30ʎ㊁45ʎ㊁60ʎ㊁90ʎ时Sb 2Se 3的表面SEM 照片㊂可以看到,当生长角度由30ʎ增加到60ʎ时,Sb 2Se 3薄膜表面的晶粒结构由不规则的棒状结构向片状结构发生转变,晶粒逐渐长大,在基底倾角为60ʎ时薄膜表面晶粒达到200nm㊂当生长角度为90ʎ时,薄膜表面变的较为致密平整,且没有出现针孔和裂隙的现象㊂Kondrotas 等[13]研究表明,Sb 2Se 3的形貌特性主要依赖于生长速率,生长速率最初与衬底和膜之间的相互作用有关㊂而CdS 衬底则能够促进(hkl)晶核取向[13],从而导致薄膜在该方向上的生长速率加快㊂不同的基底倾角能够在薄膜的生长过程中诱导晶粒向某一取向生长,此外更倾斜的角度可以1066㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷阻碍蒸发前驱体在管内的输运,增加了蒸发前驱体在衬底表面的滞留时间,从而有利于促进晶粒长大㊂然而倾角为90ʎ时,严重的阻碍作用导致蒸发前驱体填补了片状结构的间隙,从而表现为平面生长㊂图3㊀不同基底倾角的Sb2Se3薄膜SEM照片Fig.3㊀SEM images of Sb2Se3films with different substrate inclination2.3㊀光学特性分析通过近红外-紫外可见光反射谱研究薄膜的反射特性,并计算得到薄膜的带隙㊂图4(a)显示了在不同生长角度下的Sb2Se3薄膜的反射率对比曲线图,从图中可以看出,当基底倾角为60ʎ时,在波长小于1100nm 范围内反射率最小㊂将测得的反射率数值进行Kubelka-Munk转换[14],定义为F(R),通过Tauc公式可计算不同基底倾角的Sb2Se3薄膜的光学带隙(E g):[F(R)hν]1n=A(hν-E g)(1)式中:A为常数,hν为光子能量,n为系数㊂由于Sb2Se3属于直接带隙半导体材料,所以n为1/2㊂带隙可以通过[F(R)hν]2对hν作图,利用直线部分外推至横坐标交点来确定㊂不同基底倾角(30ʎ~90ʎ)的E g计算的结果分别为1.169eV㊁1.172eV㊁1.163eV㊁1.166eV,可以看到当基底倾角为60ʎ时,薄膜的禁带宽度最小,如图4(b)所示㊂目前文献[15]报道的Sb2Se3带隙值在1.17eV左右,与计算的结果非常接近㊂较低的带隙对于太阳电池的吸收层而言,意味着可以将更多低能量的光进行充分吸收,这有利于提高电池的光电转换效率㊂图4㊀(a)不同基底倾角Sb2Se3薄膜的红外-紫外可见光反射谱;(b)[F(R)hν]2与hν的关系图Fig.4㊀(a)NI-UV spectra of Sb2Se3films with different substrate inclination;(b)relationship between[F(R)hν]2and hν㊀第3期白晓彤等:VTD法制备不同基底倾角的硒化锑薄膜及太阳电池1067 2.4㊀电池特性分析通过对制备结构为FTO/CdS/Sb2Se3/C的电池进行I-V测试,以获得电池的特征参数(开路电压(Voc)㊁电流密度(Jsc)㊁填充因子(FF)㊁电池效率(η))㊂从图5(a)可知,随着基底倾角的增加,电池特性的各个参数值基本都呈先增大后减小的趋势㊂由于在四种角度下生长的薄膜带隙变化并不大,因而电池的特性参数可能受薄膜结构的影响㊂基底倾角为60ʎ的薄膜,除了具有较小的带隙之外,纵向片状结构能够减小反射,有利于光吸收;此外该条件下Sb2Se3薄膜的(221)择优生长取向有利于载流子的传输,使电池器件光电转化效率及其各项参数均为最佳㊂然而片状结构的孔洞容易在制备碳电极的过程中造成碳的渗透,从而形成漏电通道,使得器件的填充因子较低㊂除此之外,碳浆中含有胶粘剂,其中的酸性物质会使Sb2Se3薄膜表面恶化,导致电极不能与Sb2Se3的晶粒紧密结合,接触电阻增大,两方面原因都导致了其电池效率不高[16]㊂根据所参考的文献得知,当前硒化锑薄膜太阳电池的研究中,大多数采用贵重金属金(Au)作为电极,其电池效率普遍可达5%~8%,主要由于Au具有较高的功函数(5.1eV),避免了较大的空穴传输势垒,且作为惰性金属的Au可以有效避免界面缺陷的问题[16]㊂但Au电极的使用会加大实验成本,且不利于大面积应用,而廉价的碳电极是一个较好选择㊂图5(b)为基底倾角为60ʎ时太阳电池的I-V曲线图以及相关参数,其开路电压为0.339V,电流密度为19.08mA/cm2,填充因子为36.85%,电池效率为2.38%㊂图5㊀(a)不同基底倾角的Sb2Se3薄膜太阳电池性能的比较图;(b)基底倾角为60ʎ时太阳电池的I-V曲线及参数Fig.5㊀(a)Performance comparison diagram of Sb2Se3thin film solar cells with differentsubstrate inclination;(b)I-V curve and parameters of solar cell with substrate inclination of60ʎ3㊀结㊀论本文利用VTD法制备了以FTO/CdS为基底的Sb2Se3薄膜,主要研究了不同生长角度对薄膜性能的影响,并制备了FTO/CdS/Sb2Se3/C结构的太阳电池器件㊂对薄膜的结构和光学特性进行了研究㊂实验结果表明,Sb2Se3的生长取向与生长角度有关,随着生长角度的增加,晶粒的生长取向由(120)晶面向(221)晶面发生转变,晶粒形貌由棒状结构转变为片状结构,同时发现基底倾角为60ʎ时的Sb2Se3薄膜晶粒尺寸最大㊂通过对其进行近红外-紫外反射谱的研究,发现在波长小于1100nm范围内基底倾角为60ʎ时薄膜的反射率最低,同时利用Kubelka-Munk转换及Tauc公式可计算得到其带隙值为1.163eV,在该条件下制备的电池器件效率为2.38%,然而其填充因子只有36.85%,如何提升该结构电池的填充因子值,从而提高电池的光电转换效率还需进一步的研究讨论㊂参考文献[1]㊀LI Y Z,LI F,LIANG G X,et al.Sb2Se3thin films fabricated by thermal evaporation deposition using the powder prepared via mechanicalalloying[J].Surface and Coatings Technology,2019,358:1013-1016.[2]㊀LIU X S,CHEN J,LUO M,et al.Thermal evaporation and characterization of Sb2Se3thin film for substrate Sb2Se3/CdS solar cells[J].ACSApplied Materials&Interfaces,2014,6(13):10687-10695.1068㊀新型功能材料硅酸盐通报㊀㊀㊀㊀㊀㊀第41卷[3]㊀YUAN C C,ZHANG L J,LIU W F,et al.Rapid thermal process to fabricate Sb2Se3thin film for solar cell application[J].Solar Energy,2016,137:256-260.[4]㊀LI D B,YIN X X,GRICE C R,et al.Stable and efficient CdS/Sb2Se3solar cells prepared by scalable close space sublimation[J].NanoEnergy,2018,49:346-353.[5]㊀WEN X X,CHEN C,LU S C,et al.Vapor transport deposition of antimony selenide thin film solar cells with7.6%efficiency[J].NatureCommunications,2018,9:2179.[6]㊀YANG K,LI B,ZENG G G.Effects of substrate temperature and SnO2high resistive layer on Sb2Se3thin film solar cells prepared by pulsedlaser deposition[J].Solar Energy Materials and Solar Cells,2020,208:110381.[7]㊀YANG K,LI B,ZENG G G.Sb2Se3thin film solar cells prepared by pulsed laser deposition[J].Journal of Alloys and Compounds,2020,821:153505.[8]㊀ZHANG J W,LIAN W T,YIN Y W,et al.All antimony chalcogenide tandem solar cell[J].Solar RRL,2020,4(4):2000048.[9]㊀NGO T T,CHAVHAN S,KOSTA I,et al.Electrodeposition of antimony selenide thin films and application in semiconductor sensitized solarcells[J].ACS Applied Materials&Interfaces,2014,6(4):2836-2841.[10]㊀LAI Y Q,CHEN Z W,HAN C,et al.Preparation and characterization of Sb2Se3thin films by electrodeposition and annealing treatment[J].Applied Surface Science,2012,261:510-514.[11]㊀景宝堂.VTD法制备Sb2Se3薄膜及其superstrate结构太阳能电池的研究[D].锦州:渤海大学,2020:27-29.JING B T.Research on fabrication of Sb2Se3thin films by VTD method and application for superstrate-type solar cells[D].Jinzhou:Bohai University,2020:27-29(in Chinese).[12]㊀LIU Y Q,ZHANG M,WANG F X,et al.Facile microwave-assisted synthesis of uniform Sb2Se3nanowires for high performance photodetectors[J].J Mater Chem C,2014,2(2):240-244.[13]㊀KONDROTAS R,ZHANG J,WANG C,et al.Growth mechanism of Sb2Se3thin films for photovoltaic application by vapor transport deposition[J].Solar Energy Materials and Solar Cells,2019,199:16-23.[14]㊀ZHANG L R,QU J J,YU T W,et al.Control of the structure and photoelectrical properties of Cu(InGa)Se2film by Ga deposition potential intwo-step electrodeposition[J].Journal of Materials Science:Materials in Electronics,2018,29(23):20104-20112.[15]㊀陈文浩.气相转移沉积法制备硒化锑薄膜太阳能电池及其性能研究[D].武汉:华中科技大学,2018:5-6.CHEN W H.Preparation and characterization of vapor transport deposited Sb2Se3thin film solar cells[D].Wuhan:Huazhong University of Science and Technology,2018:5-6(in Chinese).[16]㊀张㊀军.硒化锑薄膜太阳能电池的背接触研究[D].武汉:华中科技大学,2019:45-46.ZHANG J.The back contacts for antimony selenide thin film solar cells[D].Wuhan:Huazhong University of Science and Technology,2019:45-46 (in Chinese).。

一、半导体缺陷1.位错：位错又可称为差排（英语：dislocation），在材料科学中，指晶体材料的一种内部微观缺陷，即原子的局部不规则排列（晶体学缺陷）。

从几何角度看，位错属于一种线缺陷，可视为晶体中已滑移部分与未滑移部分的分界线，其存在对材料的物理性能，尤其是力学性能，具有极大的影响。

产生原因：晶体生长过程中，籽晶中的位错、固-液界面附近落入不溶性固态颗粒，界面附近温度梯度或温度波动以及机械振动都会在晶体中产生位错。

在晶体生长后，快速降温也容易增殖位错。

（111）呈三角形；（100）呈方形；（110）呈菱形。

2.杂质条纹：晶体纵剖面经化学腐蚀后可见明、暗相间的层状分布条纹，又称为电阻率条纹。

杂质条纹有分布规律，在垂直生长轴方向的横断面上，一般成环状分布；在平行生长轴方向的纵剖面上，呈层状分布。

反映了固-液界面结晶前沿的形状。

产生原因：晶体生长时，由于重力产生的自然对流和搅拌产生的强制对流，引起固-液界近附近的温度发生微小的周期性变化，导致晶体微观生长速率的变化，或引起杂质边界厚度起伏，一截小平面效应和热场不对称等，均使晶体结晶时杂质有效分凝系数产生波动，引起杂质中杂质浓度分布发生相应的变化，从而在晶体中形成杂质条纹。

解决方案:：调整热场，使之具有良好的轴对称性，并使晶体的旋转轴尽量与热场中心轴同轴，抑制或减弱熔热对流，可以使晶体中杂质趋于均匀分布。

采用磁场拉晶工艺或无重力条件下拉晶可以消除杂质条纹。

3.凹坑：晶体经过化学腐蚀后，由于晶体的局部区域具有较快的腐蚀速度，使晶体横断面上出现的坑。

腐蚀温度越高，腐蚀时间越长，则凹坑就越深，甚至贯穿。

4.空洞：单晶切断面上无规则、大小不等的小孔。

产生原因：在气氛下拉制单晶，由于气体在熔体中溶解度大，当晶体生长时，气体溶解度则减小呈过饱和状态。

如果晶体生长过快，则气体无法及时从熔体中排出，则会在晶体中形成空洞。

5.孪晶：使晶体断面上呈现金属光泽不同的两部分，分界线通常为直线。

材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂材料厂
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智能材料结构中力与多物理场耦合理论及结构损伤/断裂理论本研究方向的成员主要基于多物理场理论和超声波相关理论技术，利用新型的微纳米级的铁电功能材料，创新地提出了针对各类材料与结构（尤其是航空材料结构）中的毫米级的损伤进行的检测和监测相关理论与技术。

团队形成了较强的凝聚力和良好的学术风气，产生了较高水平的科研成果，以下为研究骨干在近几年以来已完成的代表性阶段成果：（1）超声相控阵损伤检测中PFC换能器的研究项目负责人：骆英研究骨干：王自平、赵国旗、韩伟、虞波研究了PZT、PMN－PT等系统压电陶瓷的组成、制备技术和性能，创新地提出了用有序生长制备技术制造压电纤维复合材料及智能驱动/传感器件的新方法。

建立了一种基于新型PFC相控阵超声驱动/传感器件的超声相控阵检测系统，并成功应用于金属结构和混凝土结构的损伤检测，研制了接近国际水平的相控阵超声检测系统的原型机。

PFC片状驱动/传感器用于金属结构检测的PFC超声相控阵换能器用于混凝土结构检测的超声相控阵换能器d 、a 、N 变化时的指向性分析阵元参数变化时的波场分析基于PFC 超声相控阵驱动/传感器件的相控阵检测结果 （2）基于声发射(AE)技术的结构损伤检测方法研究骨干：骆英、顾爱军、Adudrum Marfo 、刘红光、欧晓林AE 技术作为一项独特的无损检测方法在各工程领域发挥着巨大的作用，在土木工程领域也显示出巨大的潜力。

研究了钢筋与混凝土间粘结滑移的声发射特性,并开始应用于预应力混凝土结构、钢结构、玻璃幕墙等结构的无损检测中，研究将数字图像相干法(DIC)与AE监测技术相结合，进一步验证损伤监测的准确性，为工程结构声发射检测中利用AE特性进行损伤识别奠定了基础。

CFRP碳纤维加固混凝土开孔板损伤监测桥梁声发射检测声发射与DIC检测方法比较试验装置基于Gabor小波变换理论的声发射无损检测及信号处理技术a) b) c) d)利用DIC方法测得的水平应变场判断混凝土裂缝的形成和扩展a)、b)、c)，应变场的演化，d)宏观裂缝（3）基于新型应变梯度传感器的结构损伤监测技术项目负责人：骆英研究骨干：徐晨光、李康、桑胜、王晶晶、李兴家在近10年跟踪前沿研究新型铁电功能材料及智能器件的基础上，揭示微米级挠曲电材料的力/电能量转换关系，基于微米级挠曲电结构对微损伤尖端附件的应变梯度极其敏感的特性，研制用于监测结构损伤的新型应变梯度传感器，实现在线监测损伤导致的应变梯度，进而达到超前监测结构中应力集中区域损伤的萌生。

Vol 136No 112・26・化　工　新　型　材　料N EW CH EMICAL MA TERIAL S 第36卷第12期2008年12月新材料与新技术基金项目:国家自然科学基金(20476065;20736004);国家教委留学回国基金;中国科学院过程工程研究所多相反应国家重点实验室基金(200322);中国科学院煤炭化学研究所煤转化国家重点实验室基金(20062902);合成化学江苏省重点实验室基金;苏州大学基础课化学实验教学中心;南京医科大学研发基金(N Y0586)作者简介:冯斌(1984-),男,硕士研究生,应用化学专业,研究方向磁性功能材料。

32氨丙基三乙氧基硅烷表面修饰的磁性Fe 3O 4纳米粒子合成与表征冯　斌1　任志强1　屈晶苗1　洪若瑜1,2　李洪钟2　魏东光3(1.苏州大学化学化工学院,江苏省有机合成重点实验室,苏州215123;2.中科院过程工程研究所多相反应国家重点实验室,北京100080;3.哈佛大学工程与应用科学学院,纳米尺寸研究中心,马萨诸塞州02139.)摘　要　以FeCl 3、FeSO 4为铁源,利用改进共沉淀法合成磁性纳米Fe 3O 4,在其制备的过程中加入水合肼充当还原剂和沉淀剂,采用32氨丙基三乙氧基硅烷(A PTES ),通过硅烷化反应以化学键的方式结合Fe 3O 4纳米颗粒,获得表面氨基化的磁性Fe 3O 4纳米复合颗粒。

并用XRD 、IR 、TEM 、VSM 等分析手段深入研究了AP TES 修饰前后磁性纳米颗粒结构和性能影响。

结果表明A PTES 成功包覆到磁性纳米粒子表面,其包覆率为21%;磁性颗粒粒径为20nm ,晶型为反立方尖晶石型;磁性颗粒具有很好的分散性,其磁化率为2.36×10-6,饱和磁化强度达60.8mT 。

关键词　磁性纳米颗粒,共沉淀法,表面修饰,氨基化Preparation and characterization of (32aminopropyl)triethoxysilane coatedmagnetite nanoparticlesFeng Bin 1　Ren Zhiqiang 1　Qu Jingmiao 1　Hong Ruoyu 1,2　Li Hongzhong 2　Wei Dongguang 3(11Chem.Eng.Dept.&Key Lab.of Organic Synt hesis of Jiangsu Prov.,Soochow Univ.,SIP ,Suzhou 215123;21State Key Lab.of Multip hase Reactio n ,Inst.of Proc.Eng.,Chinese Academy of Sciences ,Beijing 100080;31Center for Nanoscale Sys.,School of Eng.&Appl.Sci.,Harvard Univ.,11Oxford St.,Cambridge ,MA 02139)Abstract Using FeCl 3and FeSO 4as iron sources ,Fe 3O 4magnetic nanoparticles were synthesized by modifiedchemical co 2precipitation.Hydrazine hydrate as reducing agent and precipitator was added in the process of preparation.Magnetite nanoparticles coated with (32aminopropyl )triethoxysilane ,were prepared by silanization reaction and character 2ized by XRD ,TEM ,IR ,VSM et al.The result showed that nanoparticles were coated successf ully by A PTES ,the coat 2ing percentage was about 21%,the mean size of the magnetic nanoparticles were about 20nm ,and their morphology was inverse spinel.The A PTES coated magnetite nanoparticles demonstrated excellent dispersibility ,and had susceptibility of 2136×10-6and saturation magnetization of 6018m T.K ey w ords magnetite nanoparticle ,coprecipitation ,surface modification ,amino 2functionalization 纳米材料,特别是磁性纳米粒,是物理、化学、化工、材料科学与工程和生物医药等领域研究的热点[125]。

Table of ContentsSection 1Introduction and Safety Information:The Gene Pulser XcellSystem (1)1.1General Safety Information (1)1.2Electrical Hazards (2)1.3Mechanical Hazards (2)1.4Other Safety Precautions (2)Section 2Unpacking and System Installation (3)2.1Unpacking the System Components (3)2.2Setting up the System (4)2.2.1Setting up the Gene Pulser Xcell Main Unit and Connectingthe ShockPod (Cat. #s 165-2660, 165-2661, 165-2662,165-2666) (4)2.2.2Connecting the PC Module to the Gene Pulser Xcell MainUnit (Cat. #s 165-2660, 165-2662, and 165-2668) (5)2.2.3Connecting the CE Module to the Gene Pulser Xcell MainUnit (Cat. #s 165-2660, 165-2661, and 165-2667) (6)2.2.4ShockPod (Cat. #s 165-2660, 165-2661, 165-2662, and165-2669) (6)Section 3Gene Pulser Xcell Operating Instructions (8)3.1Section Overview (8)3.2Front Panel and Home Screen (9)3.2.1Description of Keypad (9)3.2.2Home Screen (10)3.2.3Help Screens (11)3.3Manual Operation (12)3.3.1Manual Operation (Guide Guide) (12)3.3.2Electroporation using Exponential Decay Pulses (12)3.3.3Electroporation Specifying Time Constant (14)3.3.4Electroporation using Square Wave Pulses (15)3.3.5Results Screens (17)3.3.6Saving a Program from Manual Operation (19)3.3.6A Saving in a Location without a Named User Entry (20)3.3.6B Saving in a Location with a Named User Entry (20)3.4Pre-Set Protocols (21)3.4.1Using a Pre-set Protocol (Quick Guide) (21)3.4.2Electroporation using a Pre-Set Protocol (22)3.4.3Modifying Pre-Set Protocol Parameters (25)3.4.4Saving Changes to Pre-Set Protocols (25)3.5User Protocols (26)3.5.1Using a User Protocol (Quick Guide) (26)3.5.2Creating a New User Name (26)3.5.3Creating a New User Protocol (26)3.5.4Modifying a User Protocol (30)3.5.5Deleting a User Name and a User Protocol (31)3.5.6Renaming a User Name or a User Protocol (33)3.6Last Pulse (34)3.7Optimize Operation (34)3.8Data Management (36)3.9Measurements (39)3.9.1Sample Resistance Measurements (39)3.9.2Calibration and Measurement of Capacitors in theCE Module (40)3.10User Preferences (41)3.10.1Setting the Clock (41)3.10.2Adjusting the Screen Intensity (42)3.10.3Sleep Function Setting (42)3.11The Pulse Trac System (43)3.11.1Pulse Trac System Description (43)3.11.2Pulse Trac Diagnostic Algorithm (44)Section 4Overview of Electroporation Theory (44)4.1Exponential Decay Pulses (45)4.2Square Wave Pulses (45)Section 5Factors Affecting Electroporation:OptimizingElectroporation (48)5.1Cell Growth (48)5.2DNA (49)5.3Electroporation Media (49)5.4Temperature (50)Section 6Electroporation of Bacterial Cells (52)6.1Escherichia coli (52)6.1.1Preparation of Electrocompetent Cells (52)6.1.2Electroporation (53)6.1.3Solutions and Reagents (53)6.2Staphylococcus aureus (54)6.2.1Preparation of Electrocompetent Cells (54)6.2.2Electroporation (54)6.2.3Solutions and Reagents (55)6.3Agrobacterium tumefaciens (56)6.3.1Preparation of Electrocompetent Cells (56)6.3.2Electroporation (56)6.3.3Solutions and Reagents (57)6.4Bacillus cereus (57)6.4.1Preparation of Electrocompetent Cells (57)6.4.2Electroporation (57)6.4.3Solutions and Reagents (58)6.5Pseudomonas aeruginosa (58)6.5.1Preparation of Electrocompetent Cells (58)6.5.2Electroporation (59)6.5.3Solutions and Reagents (59)6.6Streptococcus pyogenes (60)6.6.1Preparation of Electrocompetent Cells (60)6.6.2Electroporation (60)6.6.3Solutions and Reagents (61)6.7Lactobacillus plantarum (61)6.7.1Preparation of Electrocompetent Cells (61)6.7.2Electroporation (61)6.7.3Solutions and Reagents (62)Section 7Electroporation of Fungal Cells (62)7.1Saccaromyces cerevisiae (62)7.1.1Preparation of Electrocompetent Cells (62)7.1.2Electroporation (63)7.1.3Solutions and Reagents (64)7.2Schizosaccharomyces pombe (64)7.2.1Preparation of Electrocompetent Cells (64)7.2.2Electroporation (65)7.2.3Solutions and Reagents (65)7.3Pichia pastoris (65)7.3.1Preparation of Electrocompetent Cells (65)7.3.2Electroporation (66)7.3.3Solutions and Reagents (66)7.4Candida albicans (67)7.4.1Preparation of Electrocompetent Cells (67)7.4.2Electroporation (67)7.4.3Solutions and Reagents (68)7.5Dictyostelium discoideum (68)7.5.1Preparation of Electrocompetent Cells (68)7.5.2Electroporation (69)7.5.3Solutions and Reagents (69)Section 8Mammalian Cells (70)8.1Preparation of Electrocompetent Cells (70)8.1.1Attached Cells (70)8.1.2Suspension Cells (70)8.2Electroporation (70)8.3Solutions and Reagents (71)Section 9References (72)Section 10Specifications and Product Information (75)10.1System Specifications (75)10.2Product Information (76)Section 1The Gene Pulser Xcell™Electroporation SystemThe Gene Pulser Xcell is a pulse generator that uses capacitors to produce controlled exponential or square wave electrical pulses for cell electroporation. The unit is capable of producing pulses of up to 3000 V on a high-voltage circuit, and up to 500 V on a low-voltage circuit. For generating pulses on the high voltage circuit, capacitors of 10, 15, and 25 µF present in the Gene Pulser Xcell main unit are used and generating pulses on the low-voltage circuit requires use of capacitors in the CE Module. Exponential decay (or capacitance discharge) and square wave pulses are the most commonly used types of electrical pulse. Anin-depth discussion of these two waveforms can be found in Section 4.The Gene Pulser Xcell is a modular system, comprising of a main unit and two accessory modules,the CE module and the PC module, in addition to the shocking chamber and a cuvette with incorporated electrodes. The CE Module is recommended for use with the Gene Pulser Xcell main unit for electroporation of most eukaryotic cells, including mammalian cells and plant protoplasts. The CE Module should only be used with low-resistance media (<1000 ohms). For exponential decay pulses, the CE Module provides a means of controlling the capacitance of the circuit by increasing the time constant of the pulse. For square wave pulses, the CE Module provides the large capacitor necessary for delivering a square wave pulse into low resistance media. This module contains a set of capacitors with a functional range between 50 and 3275 µF and selectable in 25 µF increments. For square wave pulses, the CE Module provides the large capacitance, 3275 µF, necessary for delivering a square wave pulse into low resistance media.The PC Module is recommended for the electroporation of bacteria and fungi using exponential decay, as well as in other applications where high-voltage pulses are applied to samples of small volume and high resistance. The PC Module selects resistance of 50 ohms 1000 ohms in 50-ohm increments. The unit is used to control the resistance of the circuit by placing resistors in parallel with the sample, thereby provid-ing a means of reducing the time constant of an exponential decay pulse. This provides an effective means of controlling the time constant when using high-resistance media but has little effect on the time constant when using low-resistance media. The PC Module greatly reduces the likelihood of an arc occurring at high voltage. It is not recommended that the PC module be used for square wave pulses due to the increase in droop of the pulse that can occur (see Section 4).Both the PC Module and CE Module have integral leads that connect to the main unit (see Section 2 for installation) and both units are controlled directly from the user interface on the front panel of the main unit.1.1General Safety InformationThis Bio-Rad instrument is designed and certified to meet the safety requirements of EN61010 and the EMC requirements of EN61326 (for Class A) and conforms to the “Class A” standards for electromagnetic emissions intended for laboratory equipment applications. This instrument is intended for laboratory application only. It is possible that emissions from this product may interfere with some sensitive appliances when placed nearby or in the same circuit as those appliances. The user should be aware of this potential and take appropriate measures to avoid interference.No part of the Gene Pulser Xcell system should be used if obvious external case damage has occurred or the electronic displays are not functioning as described in the manual. This instrument is only to be used with the components provided (or their authorized additions or replacements) including, but not limited to, supplied cables and ShockPod. The operating temperature range for the Gene Pulser Xcell system and its associated components is 0–35°C.1There are no user serviceable parts within the unit. The operator should make no attempt to open any case cover or defeat any safety interlock. This instrument must not be altered or modified in any way. Alteration of this instrument will•Void the manufacturer’s warranty•Void the IEC 1010 safety certification•Create a potential safety hazardBio-Rad is not responsible for any injury or damage caused by the use of this instrument for purposes other than those for which it is intended or by modification of the instrument not performed by Bio-Rad or an authorized agent.1.2Electrical HazardsThe Gene Pulser Xcell produces voltages up to 3,000 volts and is capable of passing very high currents. When charged to maximum voltage, the instrument stores about 400 joules. A certain degree of respect is required for energy levels of this order. System safety features prevent operator access to the recessed input jacks and to the recessed electrode contacts inside the sample chamber. These mechanical interlocks should never be circumvented.The pulse button is active whenever the character space in the lower right corner is flashing. There is high voltage present whenever the pulse button is depressed and “Pulsing” is shown on the LCD display on the front of the instrument. Because of the built-in safety interlock in the ShockPod, no pulse is delivered to the cuvette when the ShockPod lid is opened. If the capacitor has been partially charged but not fired (for example, when the charging cycle has been interrupted before the pulse is delivered), some charge may remain on the internal capacitor. This charge will dissipate over 1–2 minutes. However, the user cannot make contact with any charged electrical components due to the system safety features.1.3Mechanical HazardsThe Gene Pulser Xcell contains a patented arc-protection circuit that dramatically reduces the incidence of arcing in the cuvette when high voltage is delivered into the sample. The unit incorporates a circuit that senses the beginning of an arc and diverts current from the sample within <10 µsec, preventing, or greatly reducing, mechanical, visual, and auditory phenomena at the ShockPod. Should an arc occur, the sample chamber is effective in containing these small discharges, but nonetheless we strongly recommend wearing safety glasses when using the instrument.1.4Other Safety PrecautionsAvoid spilling any liquids onto the apparatus. Use only a paper towel or a cloth wet with either water or alcohol to clean the outside surfaces of the Gene Pulser Xcell.Use only the Bio-Rad cables supplied with the Gene Pulser Xcell.Use the ShockPod only in the assembled condition. Do not attempt to circumvent the protection of the ShockPod or use it while disassembled.Verify the display segments periodically.Read the instruction manual before using the Gene Pulser Xcell Electroporation System. For technical assistance contact your local Bio-Rad office or, in the US, call technical services at 1-800-4BIORAD(1-800-424-6723).2Warning: The Gene Pulser Xcell generates, uses, and radiates radio frequency energy. If it is not used in accordance with the instructions given in this manual, it may cause interference with radio communications. The Gene Pulser Xcell has been tested and found to comply with the limits for Class A computing devices (pursuant to Subpart J of Part 15 of FCC Rules) which provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference. In this case the user will be required, at their expense, to take whatever measure may be required to correct the interference.Section 2Unpacking and System InstallationThe Gene Pulser XCell™ can be purchased as three systems as well as component parts:165-2660Gene Pulser Xcell Total System for eukaryotic and microbial cells, 100–240 V, 50/60 Hz, exponential decay and square wave delivery, includes main unit, CE Module, PCModule, ShockPod, 15 sterile cuvettes (5 each of 0.1, 0.2, and 0.4 cm gap),instruction manual165-2661Gene Pulser Xcell Eukaryotic System, 100/240 V, 50/60 Hz, exponential decay (25–3,275 µF range) and square wave delivery, includes main unit, CE Module,ShockPod, 5 sterile cuvettes (0.4 cm gap), instruction manual165-2662Gene Pulser Xcell Microbial System, 100/240 V, 50/60 Hz, exponential decay and square wave delivery, includes main unit, PC Module, ShockPod, 10 sterile cuvettes(5 each of 0.1 and 0.2 cm gap), instruction manual165-2666Gene Pulser Xcell main unit, 100/240 V, 50/60 Hz165-2667Gene Pulser Xcell CE Module, 25–3,275 µF range controlled by main unit, includes integral leads, 5 sterile cuvettes (0.4 cm gap), instruction manual165-2668Gene Pulser Xcell PC Module, 50–1,000 ohm range controlled by main unit, includes integral leads, 10 sterile cuvettes (5 each of 0.1 and 0.2 cm gap)165-2669Gene Pulser Xcell ShockPod shocking chamber, includes integral leads for connection to Gene Pulser Xcell, Gene Pulser II, or MicroPulser2.1Unpacking the System ComponentsRemove all packing material and connect components on a flat, dry surface near an appropriate electrical outlet.Upon receiving your instrument, please check that all items listed were shipped. If any items are missing or damaged, contact your local Bio-Rad office.3Section 3Gene Pulser Xcell™Operating Instructions3.1 Section OverviewThis section describes the operation of the Gene Pulser Xcell. The following summarizes the organization of this section.Section 3.2 below describes the functions of the keys on the front panel, the Home screen on the LCD display, and the Help functions built into the Gene Pulser Xcell.•The keys on the front panel of the main unit control the Gene Pulser Xcell. Section 3.2.1 describes the uses of these keys.•The Home screen provides easy access to programs built into the Gene Pulser Xcell as well as a direct method of manually entering pulse parameters to electroporate a sample. Section 3.2.2 describes these programs.•On-screen help is built into the software of the Gene Pulser Xcell. This may be accessed from any screen as described in Section 3.2.3.The Gene Pulser Xcell has three modes of operation: manual operation, pre-set protocols, and user protocols.Section 3.3 describes the Manual mode, which may be used to rapidly program the parameters necessary for delivering either an exponential decay or a square wave pulse.•Section 3.3.2 describes delivering an exponential decay pulse.•Section 3.3.3 describes delivering an exponential decay pulse but specifying a time constant rather than a capacitance and resistance value.•Section 3.3.4 describes delivering a square wave pulse.•Section 3.3.6 explains how programmed settings may be saved as user protocols.Section 3.4 describes the Pre-set protocols in which the pulse parameters have been optimized for a number of commonly used bacterial and fungal species and mammalian cell lines.•Pre-set Protocols may be called up and used directly (Section 3.4.2) or may be modified prior to being used (Section 3.4.3).• A modified Pre-set Protocol may be saved as a User Protocol (Section 3.4.4).Section 3.5 describes a custom mode (User Protocols) in which users may store optimized pulse parameters that they use in their own work.•User Protocols may be created in any of four ways:•In the User Protocols menu as a new protocol (Section 3.5.3).•In the User Protocols menu as an edited (modified) program (Section 3.5.4)•In the Manual menu as a new protocol (Section 3.3.4).•In the Pre-set Protocol Menu as a modified protocol (Section 3.4.4).•User Protocols, once created and saved, may be called up and used directly like Pre-set Protocols (Section 3.5.1).3.2 Front Panel and Home Screen3.2.1 Description of the keypadSee Figure 3.1 for a view of the Gene Pulser Xcell front panel.Alpha-numeric keys This array of keys permits entering numbers and letters into the Gene PulserXcell. Pressing the Shift key toggles between alphabetic and numeric input. Totype an alphabetic character, press the Shift key to enter alpha mode, thenpress the key with the appropriate letter. To type an a, press the 2 key once; totype a b, press the 2 key twice; to type a c, press the 2 key three times. To usethe same key twice, for example to type a then b, advance the cursor usingthe Right Arrow Key. The firmware on Gene Pulser Xcell will automaticallychange between alpha and numeric input depending on the parameter beingentered. In Protocol screens and Directory screens where a two-digit entrymust be made, the second digit must be entered within 2 seconds of the firstentry, otherwise the screen will default to the single-digit entry.Home key Returns the user to the Home screen from anywhere in the program.Back key Returns the user one level back in hierarchy toward the Home screen.Help key Displays on-screen help text.Save key Saves User Names and User Protocols.Delete key Removes only the last entry in the field; also used to remove User Name andUser Protocol files.Clear key Removes the entire line of the field.Enter key Indicates that a choice has been made and moves the cursor to the nextlocation.Arrow keys The Up and Down Arrow keys move the cursor up or down one row at a time.Depending on the screen and location of the cursor, the Right and Left Arrowsmay (1) move the cursor right or left one space at a time, (2) toggle forwardand backward one screen when there are multiple screens for the samemenu, or (3) increase or decrease numerical input values.Pulse button:Results in discharging a pulse. During this time “Pulsing” is shown on the LCDdisplay. A tone sounds to indicate that the pulse has been delivered. Whenmultiple pulses are delivered, a tone sounds after the last pulse has beendelivered. The Pulse is discharged to the electrodes if the ShockPod isconnected and the lid is closed. Otherwise, it is discharged safely within theinstrument.3.3 Manual Operation3.3.1 Manual Operation (Quick Guide)•From the Home screen:•Press Enter to select exponential decay;•Press 2, then Enter to select exponential decay but specifying a time constant;•Press 3, then Enter to select square wave.•Use the Up and Down Arrow keys to scroll through the parameter value spaces on the screen.When a parameter value is highlighted, use the keypad to enter a value, then press Enter to accept that value.•When the necessary parameter values have been entered, the Pulse button on the Gene Pulser Xcell is active.•Press the Pulse button to electroporate the sample.•Press the Back key to return to the Protocol Detail screen and to deliver another pulse.3.3.2 Electroporation using Exponential Decay PulsesSee Section 4.1 for a discussion of electroporation using exponential decay pulses.•When the Home screen (Figure 3.2) is selected, the number 1, corresponding to “Exponential protocol” is highlighted as the default choice. Press Enter to view the Protocol Detail Screen. If the number 1 on the Home screen is not highlighted, press 1 or use the Up or Down Arrow keys to highlight “Exponential protocol”, then press Enter to select. The Protocol Detail screen appears (Figure 3.3).•The following combination of parameters may be entered:Capacitance + VoltageCapacitance + Voltage + ResistanceThe three variables may be selected in any order, however, the set voltage will determine whether the high voltage or the low voltage circuit is to be used and will limit the range of the capacitance as indicated in Table 3.1. If a value for the capacitance is chosen that outside the range of the system, this value will default to the closest allowable value.Specifying a resistance value requires that the PC Module be attached. This is always recommended with high resistance media (i.e., >600 ohm) such as water, sucrose, glycerol, sorbitol, or polyethylene glycol. The PC Module places a resistor in parallel with the sample to reduce the resistance of the circuit. In this way, the time constant of a high-resistance sample may be reduced and controlled.•When the necessary parameter values have been specified, a flashing “P” appears in the character space in the lower right corner of the LCD display indicating that the pulse button on the Gene Pulser Xcell is active and that a pulse may be delivered.•Press the Pulse button to deliver a pulse. When the Pulse button is depressed, the LCD display will blank then show “Pulsing”. Upon completion, a tone will sound and the pulse measurements will be displayed on the Protocol Results screen (see Figure 3.8, Section 3.3.5).•Use the Left and Right Arrow keys to toggle between the Protocol Results screen and the last Protocol Detail screen.•With the Protocol Detail screen on the LCD display another pulse can be delivered using the same pulse parameters. To change the pulse conditions, press Enter; the cursor appears in the voltage parameter value. The parameters may be changed as described above.•To save the pulse parameters, see Section 3.3.6.•To review previously delivered pulses, see Section 3.8.3.3.5 Results ScreensAfter delivering a pulse, the LCD displays the results on a Protocol Results screen. This screen shows the results in both graphic and tabular form. Figures 3.6, 3.7, and 3.8 show examples of the results from an exponential decay pulse, an exponential decay pulse in which the time constant was specified, and a square wave pulse, respectively.Results of the last 100 pulses as well as of the pulse parameters are stored in Gene Pulser Xcell memory and are accessible from the Data Management program (Section 3.8).3.4.2 Electroporation using Pre-set ProtocolsThere are nine Pre-set Bacterial Protocols, six Pre-set Fungal Protocols, and 12 Pre-set Mammalian Protocols. These protocols are pre-programmed with the optimal parameters for the given organism. Use the Pre-set Protocols as follows.•From the Home screen, press 4 or use the Up and Down Arrow keys to highlight “Pre-set Protocols”, then press Enter to select and to show the Pre-set Protocols screen (Figure 3.12).•Press 1–3, or use the Up and Down Arrow keys, to highlight Bacterial, Fungal, or Mammalian Pre-set Protocols, then press Enter to select.•Use the alpha-numeric keypad or the Up and Down Arrow keys to scroll through the list of names.For the Bacterial and Mammalian Pre-set Protocols, use the Right and Left Arrow keys to toggle between the two screens. When the number corresponding to the desired name is highlighted, press Enter to select and to view the Protocol Detail Screen showing the electroporation parameters for that protocol. A flashing “P” in the character space in the lower right corner of the LCD display indicates that the Pulse button is active.•For example, from the Pre-set Protocols screen, press 3 to highlight “Mammalian”, then press Enter to select and to bring up the first Pre-set Mammalian Protocols screen with the names of six pre-set mammalian protocols (Figure 3.13). Press the Right and Left Arrow keys to togglebetween the two Mammalian Pre-set Protocols screens. Use the alpha-numeric keypad or the Up and Down Arrow keys to scroll through the list of names. When the desired name on theMammalian Pre-set Protocols screen is highlighted,press Enter to select that protocol and toview the Protocol Detail Screen showing the electroporation parameters for that protocol. Forexample, from the Mammalian Pre-set Protocols screen, press 1, then Enter to bring up theProtocol Detail Screen for CHO cells in a 2 mm cuvette (Figure 3.14).•Press the Pulse button to deliver a pulse. When the Pulse button is depressed, the LCD display will blank then show “Pulsing”. Upon completion, a tone will sound and the pulse measurements will be displayed on the Protocol Results screen (see Section 3.3.5).•Use the Left and Right Arrow keys to toggle between the Protocol Results screen and the last Protocol Detail screen.•With the Protocol Detail screen on the LCD display another pulse can be delivered using the same pulse parameters. To change the pulse conditions, press Enter; the cursorappears in the voltage parameter value. The parameters may be changed as described in Section 3.4.3.•To review previously delivered pulses, see Section 3.8.3.4.3 Modifying Pre-set Protocol ParametersThe parameters for a Pre-set protocol may be changed as follows.•From the Protocol Detail screen, press the Up or Down Arrow keys to highlight the value for one of the parameter settings (voltage, capacitance, or resistance for exponential decay pulses;voltage or time constant for time constant mode; pulse length, voltage, number of pulses, or pulse interval for square wave pulses). (Note: the waveform cannot be changed in the Pre-set Protocols Mode.) When the desired parameter is selected, use the alpha-numeric keypad to input the new value.Alternatively, use the Right and Left Arrow keys to incrementally increase or decrease, respectively, the parameter value. Use the Delete or Clear keys to correct entries. When the correct value has been specified, press Enter. If a value outside the limits of the Gene Pulser Xcell is selected, the value in the field will default to the closest permitted value. Use the Up and Down Arrow keys to select other parameter values to be changed, then use the alpha-numeric keypad or the Left and Right Arrow keys to enter the desired value.• A pulse may be delivered when appropriate parameters have been entered in the Protocol Detail screen and the character space at the lower right of the LCD display is flashing “P”.•To return to the last Protocol Detail screen, press the Back key or the Left Arrow key. Another pulse may be delivered using the same parameters shown on the LCD display. To return to the Protocol Results Screen, press the Right Arrow key. (Note: Returning to the Protocol Detail Screen returns to the modified parameters. To return to the Pre-set Protocol, press the Back key again to return to the Pre-set Protocols screen. This will remove any changes made.)•To change the pulse conditions, with the Protocol Detail screen on the LCD display, press Enter;the cursor appears in the voltage parameter value. The parameters may be changed as described above.•To review previously delivered pulses, see Section 3.8.3.4.4 Saving Changes to Pre-set ProtocolsChanges to a Pre-set Protocol may be saved as a User Protocol as follows:•Change the Pre-set Protocol as described in Section 3.4.3.•With the Protocol Detail screen open, press Save.•The first User Directory screen will appear (Figure 3.9); the second line will read “Choose location for protocol”.•Use the Right and Left Arrow keys to toggle between the two User Directory screens. Press 1–12 or use the Up and Down Arrow keys to highlight the User Name under which to store the protocol.Press Enter to select the User Name. The User Protocols screen will appear (Figure 3.10); the second line will read “Choose location for protocol”. If it is necessary to create a new User Name, seeSection 3.5.2.•Use the Right and Left Arrow keys to toggle between the two User Protocols screens. Press 1–12 or use the Up and Down Arrow keys to highlight a location for the new protocol. A protocol may be stored in a position without an entry (see Section 3.3.6A) or in a position with an entry (seeSection 3.3.6B). If necessary, delete a User Protocol as described in Section 3.5.5.•To use the saved protocol, press Enter to view the Protocol Detail screen. Press the Pulse button to deliver a pulse.。

第52卷第12期表面技术2023年12月SURFACE TECHNOLOGY·315·医用镁合金微弧氧化/有机复合涂层的研究现状及演进方向冀盛亚a，常成b，常帅兵c，倪艳荣a，李承斌a（河南工学院 a.电缆工程学院 b.车辆与交通工程学院c.电气工程与自动化学院，河南 新乡 453003）摘要：医用镁及镁合金过快的降解速率严重缩短了其有效服役时间，过高的析氢速率引发局部炎症，束缚了其临床应用前景。

微弧氧化（MAO）/有机复合涂层良好的抑蚀降析性能，在医用镁及镁合金表面改性领域展现出巨大的应用潜力。

首先，从有机材料（植酸（PA）、壳聚糖（CS）、硬脂酸（SA）、多巴胺（DA）、聚乳酸-乙醇酸共聚物（PLGA）、聚乳酸（PLA）、聚已内酯（PCL））自身的组织及性能特征入手，分析了单一有机涂层提高镁及镁合金耐蚀性的作用机理，并指出单一涂层自身的性能弱点（单一MAO涂层微孔和裂纹的不可避免，单一有机涂层与镁合金结合强度低，易于剥落）限制了对镁合金降解保护效能。

其次，从结合强度、耐蚀性、多功能性（生物安全性、生物相容性、诱导再生性、抑菌抗菌性、载药缓释性等）的角度，详细阐述了各MAO/有机复合涂层的结构特点、优势特征。

在此基础上，明确指出以MAO/PCL （MAO/CS）复合涂层为基底涂层，通过PCL（CS）涂层与其他涂层的交叉组合，是实现医用镁合金植入材料的生物活性及多功能性的最佳路径。

最后，对镁合金MAO/有机复合涂层的演进方向进行了科学展望。

关键词：镁合金；微弧氧化；有机材料；复合涂层；演进方向中图分类号：TG174.4 文献标识码：A 文章编号：1001-3660(2023)12-0315-20DOI：10.16490/ki.issn.1001-3660.2023.12.026Research Status and Evolution Direction of Micro-arc Oxidation/Organic Composite Coating on Medical Magnesium Alloy SurfaceJI Sheng-ya a, CHANG Cheng b, CHANG Shuai-bing c, NI Yan-rong a, LI Cheng-bin a(a. School of Cable Engineering, b. School of Vehicle and Traffic Engineering, c. School of Electrical Engineering andAutomation, Henan Institute of Technology, Henan Xinxiang 453003, China)ABSTRACT: Good biosafety, biocompatibility and valuable self-degradation properties endow medical magnesium and magnesium alloys with great potential to replace inert implant materials in the field of traditional clinical applications.The excessive degradation rate of magnesium alloy, however, leads to its premature loss of structural integrity and mechanical support, being unable to complete the effective service time necessary for tissue healing of the implant site. At the same time, it is also its excessive degradation rate that leads to the intensification of hydrogen evolution reaction of收稿日期：2023-02-01；修订日期：2023-05-14Received：2023-02-01；Revised：2023-05-14基金项目：河南省科技攻关项目（222102310337，222102240104，232102241029）；博士科研资金（9001/KQ1846）Fund：Henan Province Science and Technology Research Project (222102310337, 222102240104, 232102241029); Doctoral Research Funding (9001/KQ1846)引文格式：冀盛亚, 常成, 常帅兵, 等. 医用镁合金微弧氧化/有机复合涂层的研究现状及演进方向[J]. 表面技术, 2023, 52(12): 315-334.JI Sheng-ya, CHANG Cheng, CHANG Shuai-bing, et al. Research Status and Evolution Direction of Micro-arc Oxidation/Organic Composite·316·表面技术 2023年12月magnesium alloy. Because it cannot be absorbed by the human body in a short time, the excessive H2 will easily gather around the implant or form a subcutaneous airbag, which will not only cause the inflammation of the implant site, but also hinder the adhesion and growth of cells in the implant, limiting its clinical application prospects. Surface modification technology can effectively delay the degradation rate of medical magnesium and magnesium alloys, and reduce the rate of hydrogen evolution.Firstly, starting from the structure and performance characteristics of organic materials (phytic acid (PA), chitosan (CS), stearic acid (SA), dopamine (DA), polylactic acid glycolic acid copolymer (PLGA), polylactic acid (PLA), and polycaprolactone (PCL)), the mechanism of improving the corrosion resistance of magnesium and magnesium alloys by a single organic coating was analyzed, and the performance weaknesses of a single coating were also pointed out: ①Micro arc oxidation (MAO) is an anodic oxidation process that generates a highly adhesive ceramic oxide coating on the surface of an alloy immersed in an electrolyte through high voltage (up to 300 V) spark discharge. The continuous high voltage discharge and the bubbles generated by the reaction bring about the inevitable occurrence of a large number of volcanic micropores and cracks in the coating. The diversity of discharge modes also gives rise to the unpredictable morphology of micropores and cracks. Therefore, the preparation of a single MAO coating on different alloy surfaces does not only require proper adjustment of MAO electrical parameters (current density, voltage, duty cycle, frequency, oxidation time) and the coupling effect of its electrolyte system to decrease (small) the pores and cracks on the MAO coating surface, but also increases the sealing process at the later stage. ② A single organic coating has a low bonding strength with magnesium alloy, being easy to flake off. These performance weaknesses limit the protection effect of a single coating on magnesium alloy degradation.Secondly, from the perspectives of bonding strength, corrosion resistance, and versatility (biosafety, biocompatibility, induced regeneration, antibacterial and antibacterial properties, drug loading and sustained-release properties, and so on), the structural characteristics and advantages of each MAO/organic composite coating were elaborated in detail. It has revealed that MAO/organic composite coating has an enormous application potentiality in the field of surface modification of medical magnesium and magnesium alloys, thanks to its good corrosion inhibition and degradation performance. On this basis, it is clearly pointed out that, in order to achieve the biological activity and versatility of medical magnesium alloy implant materials, the best way is to adopt the MAO/PCL (MAO/CS) composite coating as the base coating and make the cross combination of PCL (CS) coating and other coatings. Finally, the evolution direction of magnesium alloy MAO/organic composite coating is scientifically predicted.KEY WORDS: magnesium alloy; micro-arc oxidation; organic materials; composite coating; evolution direction作为人体所必须的营养元素，镁不但辅助600多种酶的合成(包括参与、维护DNA和RNA聚合酶的正确结构和活性)，而且改善胰岛素稳定和糖类正常代谢、舒张血管、降低冠心病、高血压及糖尿病的患病风险[1]。

TCO磁控溅射专业词汇TCO（Transparent conductive oxide）玻璃，即透明导电氧化物镀膜玻璃，是在平板玻璃表面通过物理或者化学镀膜的方法均匀镀上一层透明的导电氧化物薄膜。

AZO ZnO：Al （Al-doped ZnO，Aluminum-doped zinc oxide）氧化铟锡ITO Indium-Tin-Oxide In2O3：SnO2氧化锡掺氟FTO SnO2：F其中AZO ，ITO，FTO均为TCO的一种。

磁控溅射Magnetron sputtering中频MF Mid-frequency直流DC Direct current交流AC Alternating current射频RF Radio frequency物理气相沉积PVD Physical V apor Deposition化学气相沉积CVD Chemical V apor Deposition等离子体增强化学气相沉积PECVD Plasma enhanced CVD双平面阴极Double planar Cathode孪生阴极Twin-Mag Cathode旋转阴极Rotatable CathodeAZO陶瓷靶AZO ceramic target高纯度靶high purity target透过率transmittance反射率reflectivity吸收率absorbtivity空气质量AM air mass面电阻sheet resistance辉光放电glow discharge起辉电压discharge voltage打弧arcing离子轰击ion bombardment靶中毒target poisoning载流子浓度carrier concentration霍耳迁移率Hall mobility电阻率specific resistivity四探针（测量面电阻）Four-point-probe托架carrier装片台Load locking进口室Entrance chamber加热室Heating chamber传送室transfer chamber溅射室sputter chamber冷却室Cooling chamber出口室Exit chamber冷却系统cooling system抽气系统pumping system排气装置exhaust阻挡层Barrier film透明电极Transparent electrode工艺气体Process Gas衬底温度Substrate Temperature溅射功率Sputter power功率密度Power density动态沉积速率dynamic deposition rate/dynamic sputtering speed 预溅射presputtering溅射速率Sputter rate靶材利用率target utilization靶材寿命target lifetime洛伦兹力Lorentz force磁场强度Magnetic field strength惰性气体Noble gas（Ar Argon）生产速率growing speed薄膜结构film structure热电偶thermocouple靶材冷却target cooling本底真空base pressure粗真空rough vacuum 1.01×105～1.33×103Pa高真空high vacuum 1.33×10-1～1.33×10-6Pa超高真空ultra high vacuum 1.33×10-6～1.33×10-10Pa 0.5%盐酸diluted hydrochloric acid刻蚀etching在线中频磁控反应溅射in-line reactive MF magnetron sputtering 晶粒尺寸Grain size阳极，正极node阴极，负极Cathode阴极防蚀Cathodic Protection冷阴极真空规MPG薄膜电容规CDG质量流量计MFC mass flow controller螺杆泵Screw Pump旋片泵Rotary V ane Pump罗茨泵Roots Pump分子泵Turbomolecular Pump漏率leak rate压缩空气compressed air节拍cycle time锁阀Lock valve泵组Pump Unit单晶硅Mono crystal silicon晶体硅C-Si, crystalline-silicon微晶硅microcrystal silicon非晶硅amorphous silicon a-Si:H碲化镉CdTe Cadmium-Tellurid铜铟镓硒CIGS Copper Indium Gallium Diselenide CIS Copper-Indium-Diselenide砷化镓GaAs Galllium Arsenid太阳能薄膜电池thin film solar cell非晶硅太阳电池（a—si太阳电池）amorphous silicon solar cell 附着力（薄膜与基体间）adhesion均匀（薄膜厚度）uniformity绝缘的insulating二极管Diode施主Donator受主Acceptor空穴Hole电子Electron离子Ion原子Atom光吸收Absorption of the photons太阳能电池成本收回时间Marginal cost payment time电池板模块Module额定功率Module rated power转换效率Conversion Efficiency多子Majority charge carrier描述半导体里的带电体，通常决定于掺杂的类型，例如在p型多子是空穴，n型多子则是电子。

专利名称：The magnetic rheology of the substrate it finishes and the magnetic发明人：コルドンスキー，ウィリアム,ホーガン，ステファン,カラペラ，ジェリー,プライス，アンドリュー・エス申请号：JP2002560827申请日：20020131公开号：JP4105950B2公开日：20080625专利内容由知识产权出版社提供摘要： It is a device comprising a Le - carrier wheel shaped by an improved device according to the present invention for magnetorheological fluids finishing of the substrate and are arranged vertically, attached to the recess having a horizontal axis. Carrier Hui - preferably, because it is a partially-equator of the sphere, Le is a spherical carrier surface. Carrier Hui - a radial disc plate, Le comprises a circular plate that supports the spherical extending laterally from the circular plate and is connected to the rotary drive means. A sphere inside and is encapsulated inside of the sphere, and, preferably, an electromagnet with a flat polar pieces and Antarctic piece carrier wheel - is placed in the encapsulation body of spherical section defined by the Le . Carrier Hui magnet - and extend over the approximately 120-degree central angle of Le, whereby the magnetic rheological fluid, beyond the working area and a front of the work area, the state of being partially cured is maintained. This device, carrier Hui - is useful for finishing large concave substrate, such as to extend beyond the edge of the Le. [Selection Figure Figure 3申请人：キューイーディー・テクノロジーズ・インターナショナル・インコーポレーテッド地址：アメリカ合衆国イリノイ州６０５０４，オーロラ，ノース・コモンズ・ドライブ ８７０国籍：US代理人：社本 一夫,小野 新次郎,小林 泰,千葉 昭男,富田 博行,佐久間 滋更多信息请下载全文后查看。

计算机英语第⼆版课后习题答案练习答案PART ONE Computer BasicsUnit 1 My ComputerSection A I．Fill in the blanks with the information given in the text:1．Charles Babbage; Augusta Ada Byron2．input; output3．VLSI4．workstations; mainframes5．vacuum; transistors6．instructions; software7．digit; eight; byte8．microminiaturization; chipII．Translate the following terms or phrases from English into Chinese and vice versa:1．artificial intelligence ⼈⼯智能2．paper-tape reader 纸空阅读机3．optical computer 光学计算机4．neural network 神经⽹络5．instruction set 指令集6．parallel processing 平⾏处理7．difference engine 差分机8．versatile logical element 通⽤逻辑器件9．silicon substrate 硅基10．vacuum tube 真空管（电⼦管）11．the storage and handling of data 数据的存储与处理12．very large-scale integrated circuit 超⼤规模集成电路13．central processing unit 中央处理器14．personal computer 个⼈计算机15．analogue computer 模拟计算机16．digital computer 数字计算机17．general-purpose computer 通⽤计算机18．processor chip 处理器芯⽚19．operating instructions 操作指令20．input device 输⼊设备III．Fill in each of the blanks with one of the words given in the following list, making changes if necessary:We can define a computer as a device that accepts input, processes data, stores data, and produces output. According to the mode of processing, computers are either analog or digital. They can be classified as mainframes, minicomputers, workstations, or microcomputers. All else (for example, the age of the machine) being equal, this categorization providessome indication of the computer’s speed, size, cost, and abilities.Ever since the advent of computers, there have been constant changes. First-generation computers of historic significance, such as UNIVAC, introduced in the early 1950s, were based on vacuum tubes. Second-generation computers, appearing in the early 1960s, were those in which transistors replaced vacuum tubes. In third-generation computers, dating from the 1960s, integrated circuits replaced transistors. In fourth-generation computers such as microcomputers, which first appeared in the mid-1970s, large-scale integration enabled thousands of circuits to be incorporated on one chip. Fifth-generation computers are expected to combine very-large-scale integration with sophisticated approaches to computing, including artificial intelligence and true distributed processing.IV．Translate the following passage from English into Chinese.A computer system includes a computer, peripheral（外围的）devices, and software. The electric, electronic, and mechanical devices used for processing data are referred to as hardware. In addition to the computer itself, the term “hardware”refers to components called peripheral devices that expand the computer’s input, output, and storage capabilities. Computer hardware in and of itself does not provide a particularly useful mind tool. To be useful, a computer requires a set of instructions, called software or a computer program, which tells the computer how to perform a particular task. Computers become even more effective when connected to other computers in a network so users can share information.计算机系统包括计算机、外围设备和软件。