Patent ID: 7057216

Claim:
A field effect device, comprising: a crystalline Si body of one conductivity type; a SiGe layer epitaxially disposed on said Si body; a Si layer epitaxially disposed on said SiGe layer; an insulating layer, on top of which said Si body is disposed thereon; and a source and a drain comprising SiGe in an epitaxial relation with said Si body and connected to each other by said SiGe layer and said Si layer, wherein said source and said drain are formed in recessed source/drain regions of said body, wherein said recessed source/drain regions penetrate all the way down to said insulating layer, said source and said drain having a conductivity type opposite to that of said Si body and each forming a heterojunction and a metallurgical junction with said Si body, wherein said heterojunction coincides with said metallurgical junction with a tolerance of less than about 10 nm.