Silicon-on-insulator integrated circuits with local oxidation of silicon and methods for fabricating the same

A method of fabricating an integrated circuit comprising the steps of:

• forming a plurality of shallow trench isolation (STI) regions in a semiconductor substrate, each extending at least a first depth below an upper surface of the semiconductor substrate;
• forming a gate dielectric layer over a first portion of source and drain regions of the semiconductor substrate;
• oxidizing a second portion of the semiconductor substrate, thereby forming a local oxide region that extends a second depth below an upper surface of the semiconductor substrate, wherein the first depth is greater than the second depth;
• and
• forming a gate electrode over the gate dielectric layer and the local oxide region, wherein forming the gate electrode comprises forming the gate electrode so as to be in direct abutting contact with the local oxide layer with respect to an entirety of an area of the local oxide layer over which the gate electrode extends.

An integrated circuit comprising:

• a silicon-on-insulator semiconductor substrate;
• a plurality of shallow trench isolation (STI) regions, each extending into a buried oxide layer of the silicon-on-insulator semiconductor substrate, wherein the STI regions electrically isolate devices fabricated in the semiconductor substrate;
• and
• a transistor comprising:
• source and drain regions located in the semiconductor substrate;
• a gate dielectric layer located between the source and drain regions;
• a local oxide layer located in a second portion of the semiconductor substrate and extending a depth below and a height above the upper surface of the semiconductor substrate;
• and
• a gate electrode that extends over the gate dielectric layer and the local oxide layer, wherein the gate electrode and the local oxide layer are disposed in a T-shaped configuration, and wherein the gate electrode is in direct abutting contact with the local oxide layer with respect to an entirety of an area of the local oxide layer over which the gate electrode extends;
• and
• a body contact region disposed adjacent to the local oxide layer of the transistor.