Patent ID: 9673314
Date: 2017-06-06
CPC Classifications: H01L

Claim:
1. A semiconductor device, comprising: a substrate layer; an epitaxial layer adjacent to the substrate layer; a first trench structure formed in the epitaxial layer and having a bottom and sidewalls, wherein the first trench structure further comprises filler material in contact with a source electrode; and an oxide layer that lines the sidewalls, the oxide layer having a non-uniform thickness along the sidewalls, wherein the thickness of the oxide layer at a first distance from the bottom is less than the thickness of the oxide layer at the bottom, and wherein the thickness of the oxide layer at a second distance from the bottom, greater than the first distance, is less than the thickness of the oxide layer at the first distance; wherein the epitaxial layer has a non-uniform dopant concentration, wherein the non-uniform dopant concentration varies according to the thickness of the oxide layer adjacent thereto.