Patent ID: 9263568
Filing Date: 2016-02-16
CPC Classification: H01L

Claim Text:
1. A metal-oxide-semiconductor field effect transistor (MOFET) comprising: a semiconductor on insulator (SOI) substrate having a semiconductor layer on an insulator layer, which insulator layer is on an underlying substrate; a source region and a drain region formed in the semiconductor layer; a source extension region extending from the source region towards the drain region, the source extension region having a depth that is less than the depth of the source region; a drain extension region extending from the drain region towards the source region, the drain extension region having a depth that is less than the depth of the drain region; a semiconductor channel region separating the source extension region and the drain extension region, wherein the semiconductor channel region has a doping ranging from undoped to less than 10 a doped semiconductor δ-layer of a few atomic layer thickness, having a doping higher than the doping of the channel region at the bottom of the channel region that determines the thickness of the channel region; wherein the semiconductor channel region and the semiconductor δ-layer have substantially vertical sides, with the source extension region and the drain extension region each having an edge truncated by the vertical sides of the semiconductor channel region, and wherein the semiconductor channel region does not extend through the semiconductor layer to the insulator layer, the thickness of the semiconductor channel region being between 5 nm and 15 nm and is determined to provide a fully depleted channel region during transistor operation, and provide characteristics of an active channel that reduces of the MOSFET; a gate dielectric over the channel region; a conductive gate region over the gate dielectric; whereby statistical variations of a threshold voltage of the MOSFET can be reduced.