Sources and drains are formed in n-MOS areas and p-MOS areas. The shapes of sources and drains are the same because usual transistors are symmetric. Which is a source or a drain is defined depending on the connection direction of the power supply.
P-source/drain: P-type impurities (e.g., B+) are implanted into p-MOS areas.
N-source/drain: N-type impurities (e.g., As+, P+) are implanted into n-MOS areas.
A resist pattern is formed to cover the n-MOS area, and p-type impurities (e.g., boron (B)) are implanted in the p-MOS area. After implantation, the resist pattern is removed.
A resist pattern is formed to cover the p-MOS area, and n-type impurities (e.g., phosphorus (P), arsenic (As)) are implanted in the n-MOS area. After implantation, the resist pattern is removed.
FEOL (Front End of Line: substrate process, the first half of wafer processing)
| 1. Isolation | 2. Well and channel formation | 3. Gate oxidation and gate formation
| 4. LDD formation | 5. Side wall spacers | 6. Source/drain | 7. Silicide | 8. Dielectric film |
9. Contact holes |
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