Trench mosfet with bottom oxide thickness equal to or greater than sidewall oxide thickness

Abstract

A trench MOSFET with a trench bottom oxide thickness that is equal to or greater than a trench sidewall oxide thickness, and a method of making the same. A trench, including a sidewall and a bottom, is created in a semiconductor material. A first bottom thickness of a gate oxide is deposited on the bottom, and a first sidewall thickness of the gate oxide is deposited on the sidewall. The first sidewall thickness is removed, leaving the first bottom thickness. A second sidewall thickness is grown on the sidewall of the trench, and a second bottom thickness is grown on top of the first bottom thickness. The first and second bottom thicknesses of the gate oxide form a total bottom thickness that is at least equal to the second sidewall thickness, and may be between one (1) and two (2) times greater than the second sidewall thickness.

Dependencies are inferred from the claim text.