Method for fabricating semiconductor device

Abstract

A method for fabricating a semiconductor device includes forming an active pattern on a substrate, forming sacrificial and semiconductor layers alternately stacked on the active pattern, forming a dummy gate and first source/drain trench on one side of the dummy gate by etching the stacked structure, forming a second source/drain trench on the active pattern by etching a sidewall of the sacrificial layer exposed to the first source/drain trench, forming a first inner spacer material layer along sidewall and bottom surfaces of the second source/drain trench, forming a second inner spacer material layer by anisotropic etching a first inner spacer material layer, and forming a third source/drain trench on the active pattern by isotropic etching.