Patent ID: 8841188

Claim:
A method of forming a semiconductor device comprising: forming a material stack on a semiconductor substrate, the material stack including a first dielectric layer on the semiconductor substrate, a second dielectric layer on the first dielectric layer, and a third dielectric layer on the second dielectric layer, wherein the second dielectric layer is a high-k dielectric; forming openings through the material stack to expose a surface of the semiconductor substrate; forming a doped semiconductor material in the openings through the material stack, wherein the doped semiconductor material extends from the surface of the semiconductor substrate past an interface between the first dielectric layer and the second dielectric layer; forming an intrinsic semiconductor material in the openings on the doped semiconductor material; removing the third dielectric layer selective to the second dielectric layer, the intrinsic semiconductor material and the doped semiconductor material; and forming a gate structure on a channel portion of the intrinsic semiconductor material.