Patent ID: 7833863

Claim:
A method of fabricating a closed cell trench metal-oxide-semiconductor field effect transistor (TMOSFET) comprising: depositing a first semiconductor layer upon a substrate, wherein said first semiconductor layer is doped with a first type of impurity; etching a plurality of trenches in said first semiconductor layer, wherein a first set of said plurality of trenches are substantially parallel with respect to each other and a second set of said plurality of trenches are substantially normal-to-parallel with respect to said first set of said plurality of trenches; forming a dielectric proximate said plurality of trenches; doping said first semiconductor layer proximate the bottoms of said first set of said plurality of trenches with said first type of impurity; doping said first semiconductor layer proximate the bottoms of said second set of said plurality of trenches with a second type of impurity; depositing a second semiconductor layer in said plurality of trenches; doping a first portion of said first semiconductor layer with said second type of impurity, wherein the first portion of said first semiconductor layer extends below said plurality of trenches; and doping a second portion of said first semiconductor layer proximate said dielectric with said first type of impurity.