Patent ID: 8912568
Filing Date: 2014-12-16
Classification: H01L

Abstract:
1. A method of manufacturing semiconductor device, comprising: forming a U-shaped recess in a Si substrate; forming a SiGe layer on the bottom of the U-shaped recess through epitaxial growth; performing wet etching having orientation selectivity on said Si substrate from the sidewall of said U-shaped recess by using an etchant having a higher etching rate with respect to Si as compared to SiGe, so as to form a Σ-shaped recess; wherein in the step of forming a SiGe layer on the bottom of said U-shaped recess through epitaxial growth, a SiGe thin film is also formed on the sidewall of said U-shaped recess, the thickness of which is less than the thickness of said SiGe layer on the bottom of said U-shaped recess, the method further comprising: etching to remove said SiGe thin film before the wet etching of the Si substrate, while retaining at least a portion of said SiGe layer on the bottom of said U-shaped recess to cover the Si substrate at the bottom of said U-shaped recess; wherein in said step of forming the SiGe layer on the bottom of said U-shaped recess through epitaxial growth comprise using one or more process gases chosen from the group consisting of: SiH GeH HCl; B H wherein the flow rate of H