Method of fabricating semiconductor devices

Abstract

Method of fabricating a semiconductor device includes forming a gate having a first material on a substrate and forming a layer of a second material overlaying the gate. Sidewall spacers are formed on opposite sides of the gate. The substrate is dry etched using the layer of second material and the sidewall spacers as a mask forming a recess in the substrate between two adjacent gates. A liner oxide layer is formed on inner walls of the recess. The liner oxide layer is removed by isotropic wet etching. Orientation selective wet etching is performed on the recess to shape the inner wall of the recess so as to cause the inner wall of the recess to be sigma-shaped. By removing the substrate portions having lattice defects due to dry etching through oxidation and wet etching, defect-free epitaxial growth performance is realized.