Patent ID: 7855128

Claim:
A method for fabricating a semiconductor device, comprising the steps of: providing a handle wafer comprising a mechanical substrate and an insulator layer substantially overlying the mechanical substrate; providing a donor wafer having a surface; implanting hydrogen in the donor wafer through the surface to form a bubble layer; doping the donor wafer with at least one dopant through the surface to form a doped layer proximal to the bubble layer; bonding the handle wafer to the donor wafer at the surface to form a combined wafer having a portion substantially underlying the bubble layer; removing a portion of the combined wafer substantially underlying the bubble layer to expose a seed layer; and growing an epitaxial layer substantially overlying the seed layer, wherein at least one dopant diffuses into the epitaxial layer such that, at completion of the growing of the epitaxial layer, there exists a net dopant concentration profile in the seed layer and the epitaxial layer which has maximum value at an interface between the seed layer and the insulator layer and which decreases monotonically with increasing distance from the interface within at least a portion of at least one of the seed layer and the epitaxial layer, and wherein the net dopant concentration profile has a slope which decreases monotonically at a first average rate within at least of one of the seed layer and the epitaxial layer, and decreases monotonically at a second average rate that is slower than the first average rate within at least one of the seed layer and the epitaxial layer.