Patent ID: 7060567

Claim:
A method of fabricating a trench power metal-oxide-semiconductor field effect transistor (MOSFET), comprising: forming an epitaxial layer and a mask layer having a first opening sequentially over a substrate; forming a pair of spacers on the sidewalls of the first opening; removing a portion of the mask layer using the pair of spacers as a mask to form a second opening that exposes the surface of the epitaxial layer; removing the pair of spacers; forming a trench in the epitaxial layer using the mask layer as a mask; removing the mask layer; forming a gate oxide layer over the epitaxial layer and the surface of the trench; forming a gate layer to fill the trench; forming a body well region in the epitaxial layer adjacent to the sidewalls of the trench; and forming a source region in the body well region on each side at the top of the trench.