Patent ID: 8373233

Claim:
A semiconductor device on a silicon substrate comprising: a gate electrode; an oxide layer having an upper surface adjacent to the gate electrode; a source region comprising boron and phosphorous at a dopant level of more than 10 20 atom/cm 3 , a portion of an upper surface of the source region being adjacent to a lower surface of the oxide layer and at least a portion of a lower surface of the source region being adjacent to the silicon substrate, the source region being substantially free of carbon; a source extension region disposed adjacent to the source region, the source extension region comprising at least one of germanium (Ge), carbon (C), or iron (Fe), an upper surface of the source extension region being adjacent to the lower surface of the oxide layer, the source region and the source extension region being separated from the gate electrode by the oxide layer; a drain region comprising boron and phosphorous at a dopant level of more than 10 20 atom/cm 3 , a portion of an upper surface of the drain region being adjacent to the lower surface of the oxide layer and at least a portion of a lower surface of the drain region being adjacent to the silicon substrate, the drain region being substantially free of carbon; a drain extension region disposed adjacent to the drain region, the drain extension region comprising at least one of germanium (Ge), carbon (C), or iron (Fe), an upper surface of the drain extension region being adjacent to the lower surface of the oxide layer, the drain region and the drain extension region being separated from the gate electrode by the oxide layer; and a channel region disposed between the source extension region and the drain extension region and separated from the gate electrode by the oxide layer, the source extension region extending between the channel region and the source region and the drain extension region extending between the channel region and the drain region, wherein the channel region is stressed by the source region and the drain region.