• Strip Nitride layer - Phosophoric acid (磷酸) or plasma etch,选择性问题 • 薄的SiO2层,厚的Si3N4层,避免鸟喙(bird’s beak)的影响
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2.3 N阱和P阱的形成
P-well Fabrication
• Photolithography (套刻) - Mask #2 pattern alignment and UV exposure - Rinse away non-pattern PR
Si,(100), P Type,25~50Ωcm
• -
Substrate selection: moderately high resistivity (25-50 ohm-cm) (100) orientation 1st Mask Photoresist P- type.
• spinning and baking @ 100º C (≈ 0.5 1.0 µ m)
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2.5 前端或延伸区(LDD)的形成
目标:
•NMOS器件中的N-注入区 •PMOS器件中的P-注入区 •多晶硅栅的两侧形成侧壁隔离层的薄氧 化层
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Extension (LDD) Formation NMOS
• Photolithography - Mask #7 pattern alignment and UV exposure - Rinse away non-pattern PR • Ion Implantation - P+ ion bombardment - 50keV for 5 × 1013cm-2 • Strip Photoresist LDD: • Lightly Doped Drain (轻掺杂漏) • Reduce short channel effects due to gate voltage magnitudes and electric fields • Source and Drain must be layered as NMOS:N+ N- P or PMOS: P+ P- N