Tall relaxed high percentage silicon germanium fins on insulator

摘要

A method is provided for forming tall silicon germanium alloy fin structures on a surface of an insulator layer. The silicon germanium alloy fin structures have a high germanium content (i.e., 50 atomic percent or greater), a low defect density (i.e., 1E2 or less defects per square cm) and a high relaxation value (i.e., 80% or greater).

主权项

1. A method of forming a semiconductor structure, said method comprising:
forming an epitaxial semiconductor material fin stack comprising, from bottom to top, a first silicon germanium alloy fin portion of a first germanium content, a silicon fin portion and a second silicon germanium alloy fin portion of said first germanium content within at least one opening formed within a patterned material stack comprising, from bottom to top, first hard mask portions and second hard mask portions, said opening exposing a surface of a silicon substrate; forming an anchoring structure on said patterned material stack and said epitaxial semiconductor material stack; replacing each first hard mask portion and said first silicon germanium alloy fin portion with an insulator layer; removing said anchoring structure; performing a flash laser anneal to melt and recrystallize said second silicon germanium alloy fin portion and to provide a silicon germanium alloy pre-fin structure having said first germanium content; and performing a thermal mixing process to convert said silicon germanium alloy pre-fin structure and said silicon fin portion into a silicon germanium alloy fin structure having a second germanium content that is less than said first germanium content.