| 摘要 |
When forming sophisticated gate electrode structures requiring a threshold adjusting semiconductor alloy for one type of transistor, a recess is formed in the corresponding active region, thereby providing superior process uniformity during the deposition of the semiconductor material. Moreover, the well dopant species is implanted after the recessing, thereby avoiding undue dopant loss. Due to the recess, any exposed sidewall surface areas of the active region may be avoided during the selective epitaxial growth process, thereby significantly contributing to enhanced threshold stability of the resulting transistor including the high-k metal gate stack.
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