Patent ID: 7081397
Filing Date: 2006-07-25
Classification: H01L

Abstract:
1. A method of forming a lateral trench in a semiconductor substrate comprising the steps as follows: formation of a lateral implant mask over a top surface of the semiconductor substrate; implanting a heavy concentration of dopant into the substrate through the lateral implant mask forming a lateral implant region in the substrate; stripping the lateral implant mask exposing the top surface of the substrate; formation of an epitaxial silicon layer over the top surface of the substrate burying the lateral implant region; formation of a trench mask over the epitaxial layer; etching a trench reaching through the epitaxial layer and the lateral implant region; formation of oxidized trench sidewalls, an oxidized trench bottom and oxidized sidewalls of the lateral implant region; etching the oxidized sidewalls of the lateral implant region until the lateral implant region is exposed; and formation of a laterally extending trench in the substrate by etching the lateral implant region.