Method of fabricating a trench MOSFET

摘要

A trench MOSFET (20) is formed by creating a trench (19) in a semiconductor substrate. A portion of either a side wall of the trench or the bottom of the trench is implanted with an implant species. An insulating layer (21) is then grown overlying the bottom and side wall of the trench (19). The implant species is selected such that the insulating layer (21) grows more quickly on the bottom of the trench than on the side wall of the trench, resulting in a thicker insulating layer in the bottom of the trench than on the trench side walls.