Patent ID: 7147709
Filing Date: 2006-12-12
Classification: C30B,H01L

Abstract:
1. A method of forming a strained semiconductor layer comprising: a wafer having a first lattice constant growing a strained first semiconductor layer having a graded dopant profile on said wafer, wherein said dopant imparts a second lattice constant to said first semiconductor layer; growing a strained boxed second semiconductor layer having said second lattice constant on said first semiconductor layer; growing a sacrificial third semiconductor layer having said first lattice constant on said second semiconductor layer; etch annealing said third and second semiconductor layer, wherein said third semiconductor layer is removed and said second semiconductor layer is relaxed; growing a fourth semiconductor layer having said second lattice constant on said second semiconductor layer, wherein said fourth semiconductor layer is relaxed; and growing a strained fifth semiconductor layer having said first semiconductor lattice constant on said fourth semiconductor layer.