Re-growing source/drain regions from un-relaxed silicon layer

摘要

A method of forming an n-type metal-oxide-semiconductor (NMOS) field-effect transistor (FET) includes forming a silicon germanium layer, and forming a silicon layer over the silicon germanium layer. A gate stack is formed over the silicon layer. The silicon layer is recessed to form a recess adjacent the gate stack. A silicon-containing semiconductor region is epitaxially grown in the recess to form a source/drain stressor, wherein the silicon-containing semiconductor region forms a source/drain region the NMOS FET.