| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a MOS device for improving reliability by reducing the number of processes, especially for controlling threshold. SOLUTION: A p-type well is formed on an n-type silicon substrate and an ion implantation process for controlling threshold is executed to each MOS formation region until a process (e). In the process (e), a polysilicon gate electrode is formed, but no doping is made at this time, and n-type and p-type polysilicon gates are formed at nMOS and pMOS in processes (f) and (g) for forming a source a drain. When the polysilicon gate is n and p types, for example a threshold voltage Vth differs by approximately 1 V according to the work function difference. Therefore, adjustment can be made, so that the threshold voltage Vth is positive (for example, +0.6 V) in the n-poly nMOS indicated by a process (h) for example in the nMOS, and the threshold voltage Vth becomes negative (for example, -0.4 V) in the p-poly nMOS, thus manufacturing two types of transistors of nMOSD and nMOSE by performing one-time ion implantation process for controlling threshold.
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