Patent ID: 8168507

Claim:
A method for forming a memory device comprising: forming at least one dielectric layer on an upper surface of a semiconductor on insulator (SOI) substrate, the SOI substrate includes a first semiconductor layer overlying a buried dielectric layer, in which the buried dielectric layer is overlying a second semiconductor layer, wherein the at least one dielectric layer has an opening that provides an exposed portion of the semiconductor on insulator (SOI) substrate; etching the exposed portion of the SOI substrate to expose at least a sidewall of the first semiconductor layer; laterally etching the sidewall of the first semiconductor layer to provide a void underlying the at least one dielectric layer; oxidizing the sidewall of the first semiconductor layer to fill at least a portion of the void, wherein an oxide containing material formed by the oxidizing of the sidewall of the first semiconductor layer does not extend outside the void formed by the laterally etching of the sidewall of the first semiconductor layer, and does not extend beyond an edge of the at least one dielectric layer that the void is underlying; forming a trench into the second semiconductor layer extending from the first semiconductor layer through the buried dielectric layer and into at least a portion of the second semiconductor layer; and forming at least one electrode in a portion of the trench present in the second semiconductor layer.