Patent ID: 7605040
Filing Date: 2009-10-20
Classification: H01L

Abstract:
1. A method of forming a metal oxide semiconductor (MOS) transistor, comprising: providing a substrate of a first conductivity type; forming a first buried layer of a second conductivity type in the substrate; forming a second buried layer of the first conductivity type in the first buried layer; forming an epitaxial layer of the second conductivity type over the substrate; forming a drift region of a second conductivity type in the epitaxial layer; forming a gate layer over the drift region; forming a body region of the first conductivity type in the drift region such that the gate overlaps a surface portion of the body region; forming a source region of the second conductivity in the body region; and forming a drain region of the second conductivity type in the drift region, the drain region being laterally spaced from the body region; wherein the first and second buried layers laterally extend from under the body region to under the drain region, and the surface portion of the body region extends between the source region and the drift region to form a channel region of the transistor.