Methods of Forming Field Effect Transistors Having Silicon-Germanium Source and Drain Regions

摘要

Methods of forming field effect transistors include forming an insulated gate electrode on a non-SiGe semiconductor substrate and then selectively etching the semiconductor substrate to define source and drain region trenches on opposite sides of the insulated gate electrode. A step is performed to remove native oxide layers from sidewalls of the source and drain region trenches. The removal of the native oxide is followed by recessing the sidewalls of the source and drain region trenches by selectively wet etching the sidewalls of the source and drain region trenches. This step of wet etching the sidewalls of the source and drain region trenches may include exposing the sidewalls to a cleaning solution including ammonium hydroxide (NH₄OH). A step is then performed to epitaxially grow SiGe source and drain regions in the source and drain region trenches. This step of epitaxially growing SiGe source and drain regions may include epitaxially growing in-situ doped SiGe source and drain regions of first conductivity type in the source and drain region trenches.