Monolithic Power Systems, Inc.
Manufacturing method of self-aligned DMOS body pickup

Abstract:

A manufacturing process of a DMOS device in a drift region in a semiconductor substrate, having: forming a polysilicon layer above the drift region; forming a block layer above the polysilicon layer; etching both the block layer and the polysilicon layer, through a window of a first masking layer to expose a window to the drift region; implanting dopants through the window to the drift region to form a body region; forming blocking spacers to wrap side walls of the polysilicon layer; implanting dopants into the body region under a window shaped by the blocking spacers to form a body pickup region; etching away the blocking spacers; performing a masking step to form gates; forming ONO spacers to wrap side walls of the gates; and performing a masking step to form source regions and drain pickup regions.