Patent ID: 7348639
Filing Date: 2008-03-25
Classification: H01L

Abstract:
1. A semiconductor device comprising: a substrate; an epitaxial silicon layer on said substrate; a first shallow trench, a second shallow trench, and a third shallow trench etched in said epitaxial silicon layer down through a first portion of a thickness of said epitaxial silicon layer; a first doped layer in said epitaxial silicon layer located between said first shallow trench and said second shallow trench; a second doped layer in said epitaxial silicon layer located at a bottom of said second shallow trench; a third doped layer in said epitaxial silicon layer located between said second shallow trench and said third shallow trench; an oxide layer that fills said first, second and third shallow trenches; wherein said second doped layer is diffused vertically down to contact said substrate and is diffused laterally into said epitaxial silicon layer; and wherein said first doped layer and said third doped layer are diffused vertically down to contact said second doped layer.