Patent ID: 7485536

Claim:
A method comprising: forming a channel region between a source region and a drain region in a layer on a substrate, a material of the channel region comprising a first dopant profile; forming a first barrier layer between the channel region and a well of the substrate, the first barrier layer comprising a second dopant profile different from the first dopant profile wherein the first dopant profile and the second dopant profile comprise a similar carrier; defining the source region and the drain region such that the source region and the drain region extend through the first barrier layer; forming a second barrier layer between the source region and the well and between the drain region and the well; and forming a source material in the source region and a drain material in the drain region and the channel and the drain material and the channel, wherein the second barrier layer is disposed between the source material and the channel and the drain material and the channel, and wherein the second barrier layer comprises a dopant profile different than a dopant profile of a material of the well and a dopant profile of each of the material of the source region and the material of the drain region.