US Patent 7682903 Method of forming a power device

A method of forming a power device includes providing a substrate, a semiconductor layer having at least a trench and being disposed on the substrate, a gate insulating layer covering the semiconductor layer, and a conductive material disposed in the trench, performing an ion implantation process to from a body layer, performing a tilted ion implantation process to from a heavy doped region, forming a first dielectric layer overall, performing a chemical mechanical polishing process until the body layer disposed under the heavy doped region is exposed to form source regions on the opposite sides of the trench, and forming a source trace directly covering the source regions disposed on the opposite sides of the trench.