Patent ID: 8921186
Filing Date: 2014-12-30
Classification: H01L

Abstract:
1. A method of making a semiconductor device, comprising: providing a substrate; forming a buried oxide layer over the substrate; forming an active silicon layer over the buried oxide layer; forming a drain region in the active silicon layer; forming a laterally double diffused (LDD) drift region in the active silicon layer adjacent to the drain region using a thermal drive to create a graded doping distribution; forming a co-implant region in the active silicon layer including a doped buried layer adjacent to the buried oxide layer, the co-implant region further including a doped base layer formed over the doped buried layer and having a doping concentration less than the doped buried layer; forming a source region in the co-implant region; forming a first shallow trench insulator (STI) along a surface of the LDD drift region with a length less than a length of the LDD drift region; forming a second STI along the surface of the LDD drift region adjacent to the drain region and separated from the first STI; and forming a polysilicon gate region over the active silicon layer between the source region and LDD drift region and at least partially overlapping the first STI.