Multiple-Gate Transistors with Reverse T-Shaped Fins

A method of forming an integrated circuit structure, the method comprising:

• providing a semiconductor substrate;
• forming a first shallow trench isolation (STI) region and a second STI region in the semiconductor substrate, wherein the semiconductor substrate comprises a portion horizontally between and adjoining the first STI region and the second STI region;
• etching the portion of the semiconductor substrate to form a recess, wherein the recess has a bottom lower than a top surface of the first STI region and no lower than a bottom surface of the first STI region, and wherein sidewalls of the first STI region and the second STI regions are exposed through the recess;
• epitaxially growing a germanium-containing region in the recess;
• etching only an upper portion of the germanium-containing region, so that remaining portions of the germanium-containing region have a reversed T-shape comprising a horizontal plate and a fin over the horizontal plate;
• forming a gate dielectric on a top surface and covering at least top portions of sidewalls of the fin;
• and
• forming a gate electrode over the gate dielectric.

An integrated circuit structure comprising:

• a semiconductor substrate;
• a first insulation region and a second insulation region in the semiconductor substrate;
• and
• an epitaxial region having a reversed T-shape and comprising:
• a horizontal plate between and adjoining the first insulation region and the second insulation region, wherein a bottom of the horizontal plate contacts the semiconductor substrate, and wherein the bottom is no lower than a bottom surface of the first insulation region;
• and
• a fin over and adjoining the horizontal plate;
• a gate dielectric on a top surface and at least top portions of sidewalls of the fin;
• and
• a gate electrode over the gate dielectric.

An integrated circuit structure comprising:

• a semiconductor substrate;
• a first shallow trench isolation (STI) region and a second STI region in the semiconductor substrate;
• a germanium-containing region having a reversed T-shape and comprising:
• a horizontal plate between and adjoining the first STI region and the second STI region, wherein a bottom of the horizontal plate contacts the semiconductor substrate and is no lower than a bottom surface of the first STI region;
• and
• a fin over and adjoining the horizontal plate;
• a gate dielectric on a top surface and top portions of sidewalls of the fin;
• and
• a gate electrode over the gate dielectric.