P-CHANNEL FIELD-EFFECT TRANSISTOR

摘要

In a channel layer made of SiGe containing C, the Ge composition varies linearly from 0% to 50% from one end closer to a silicon buffer layer toward the other end closer to a silicon cap layer, and C is contained at 0.5% selectively in a region where the Ge composition is 40% to 50% (i.e., a region where it exceeds 30%). By containing C at 0.5% in a region where the Ge composition is 40% to 50%, the strain amounts can be reduced by about 12% and 10%, respectively, while Ev is not substantially changed. It is possible to reduce a threshold value and to increase a driving current while ensuring a large critical thickness of the SiGe channel layer. <IMAGE>