| 摘要 |
<p>In a channel layer made of SiGe containing C, the Ge composition changes linearly from 0 % to 50 % in the direction from the end on the silicon buffer layer side to the end on the silicon cap layer side, and 0.5 % of C is selectively contained in a region having the Ge composition of 40 % to 50 % (i.e., a region where the Ge composition exceeds 30 %). By thus forming the region where the Ge composition ranges 40 % to 50 % and which contains 0.5 % of C, the Ev composition hardly changes although the strain can be reduced by about 12 % and 10 %, respectively. The threshold value can be reduced to augment the drive current while ensuring a large critical film thickness of the SiGe channel layer.</p> |
