Method of forming a semiconductor transistor having an epitaxial channel layer

A method for fabricating a semiconductor transistor, comprising:

• providing a substrate of a first conductivity type, wherein the substrate has a main surface;
• forming a shallow trench isolation (STI) region in the substrate to isolate an active area (AA) region, wherein the STI region comprises a trench-fill layer, and wherein an upper portion of the trench-fill layer protrudes from the main surface of the substrate;
• forming an ion well of a second conductivity type in the substrate;
• growing an epitaxial channel layer of the first conductivity type from the main surface of the substrate, wherein the epitaxial channel layer has a facet edge directly facing and in direct contact with the upper portion of the trench-fill layer, and wherein a recess is formed between the facet edge and the upper portion of the trench-fill layer;
• forming a gate dielectric layer on the epitaxial channel layer;
• forming a gate on the gate dielectric layer;
• and
• forming a source region and a drain region in the AA region, wherein the source region and the drain region have the first conductivity type.