Patent ID: 8253177
Filing Date: 2012-08-28
Classification: H01L

Abstract:
1. A metal-oxide-semiconductor field-effect transistor (MOSFET) comprising: a semiconductor substrate; a gate dielectric on the semiconductor substrate; a gate electrode on the gate dielectric; an epitaxial layer in the semiconductor substrate, a portion of the epitaxial layer being under and next to the gate dielectric, the epitaxial layer comprising a source region, a drain region, and an under-gate region, the under-gate region of the epitaxial layer having a varying thickness, the epitaxial layer in the source region and the drain region having a transition region where an upper surface of the epitaxial layer in the source region and the drain region transitions from a first height to a second height; and a dielectric spacer adjacent to the gate dielectric and the gate electrode, the dielectric spacer extending over the transition region.