Patent ID: 6995078
Filing Date: 2006-02-07
Classification: C30B,H01L,Y10S

Abstract:
1. A method of forming a semiconductor alloy layer featuring the use of only one underlying graded semiconductor alloy layer, comprising the steps of: providing a semiconductor substrate; without the use of a seed layer growing a graded, first semiconductor alloy layer directly on said semiconductor substrate, wherein the content of a component of said graded, first semiconductor alloy layer is decreased as the growth of said graded, first semiconductor alloy layer progresses, wherein said component in said graded, first semiconductor alloy layer, for a silicon—germanium alloy layer, is germanium; growing a non-graded, second semiconductor alloy layer on said graded, first semiconductor alloy layer, wherein the content of said component in said second semiconductor alloy layer is uniform, and wherein said second semiconductor alloy layer is in a strain relaxed form, and wherein said component in said graded, second semiconductor alloy layer, for a silicon—germanium alloy layer, is germanium; and forming a semiconductor layer on said relaxed second semiconductor alloy layer, wherein said semiconductor layer is comprised with tensile strain.