Semiconductor transistor device including multiple channel layers with different materials

Abstract

A semiconductor device includes a first active region, a second active region spaced apart from the first active region, a plurality of first channel layers disposed on the first active region, and a second channel layer disposed on the second active region. The semiconductor device further includes a first gate structure intersecting the first active region and the first channel layers, a second gate structure intersecting the second active region and the second channel layer, a first source/drain region disposed on the first active region and contacting the plurality of first channel layers, and a second source/drain region and contacting the second channel layer. The plurality of first channel layers includes a first uppermost channel layer and first lower channel layers disposed below the first uppermost channel layer, and the first uppermost channel layer includes a material that is different from a material included in the first lower channel layers.