Patent ID: 7625806

Claim:
A method of forming a buried silicon oxide region in a semiconductor substrate, with portions of said buried silicon oxide region formed underlying portions of a silicon shape, comprising: forming a first semiconductor layer on said semiconductor substrate; growing a second semiconductor layer on said first semiconductor layer; forming composite shapes on said first semiconductor layer, with each composite shape comprised of an overlying oxide-resistant shape and comprised of an underlying second semiconductor shape, with portions of said first semiconductor layer exposed between said composite shapes; forming spacers on the sides of said composite shapes; performing a thermal oxidation procedure to form buried silicon oxide regions in exposed top portions of said first semiconductor layer, and in portions of said first semiconductor layer located underlying second semiconductor shapes; selectively removing the oxide-resistant shapes and spacers resulting in said second semiconductor shapes, wherein a first portion of each second semiconductor shape overlays said first semiconductor layer, and wherein second portions of each second semiconductor shape overlays said buried silicon oxide regions; and forming a semiconductor device in said second semiconductor shape wherein a first portion of said semiconductor device overlays said first semiconductor layer and wherein second portions of said semiconductor device overlays said buried silicon oxide region.