Patent ID: 7812370

Claim:
A semiconductor device comprising: a low energy band-gap layer comprising a semiconductor material; a gate dielectric on the low energy band-gap layer; a gate electrode over the gate dielectric; a first source/drain region adjacent the gate dielectric, wherein the first source/drain region is of a first conductivity type, and wherein the first source/drain region has a higher band-gap than the low energy band-gap layer; a second source/drain region adjacent the gate dielectric, wherein the second source/drain region is of a second conductivity type opposite the first conductivity type, and wherein the low energy band-gap layer is between the first and the second source/drain regions; a first gate spacer and a second gate spacer on opposite sidewalls of the gate electrode; and a first offset semiconductor region comprising a same semiconductor material as the low energy band-gap layer between and adjoining the low energy band-gap layer and the first source/drain region, wherein the first offset semiconductor region is directly underlying the first gate spacer.