| 摘要 |
Semiconductor devices of different conductivity types are formed on a semiconductor substrate using a minimal number of critical masks. Embodiments include forming conductive gates on the main surface of the semiconductor substrate, and disposable amorphous silicon spacers on the sidewalls of the gates. A photoresist mask is then formed on gates and portions of the main surface intended to be implanted with impurities of a first conductivity type. Moderate or heavy source/drain implants of a second impurity type are then formed in the substrate, the disposable spacers on the unmasked gates are then removed, and lightly or moderately doped source/drain extension implants of the second impurity type are formed in the substrate. The first mask is then removed and a second photoresist mask is formed on the previously uncovered gates and implanted portions of the main surface. Moderate or heavy source/drain implants with impurities of the first conductivity type are then formed, the remaining disposable spacers are removed, and lightly or moderately doped source/drain extension implants of the first conductivity type formed. By using disposable spacers, the critical masking steps for source/drain ion implantation can be reduced to two, thereby reducing production costs and increasing manufacturing throughput.
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