Patent ID: 9536742
Date: 2017-01-03
CPC Classifications: H01L

Claim:
1. A method for forming a Lateral Double-Diffused MOSFET (LDMOS), comprising: providing a semiconductor substrate having a first conductivity type; forming a first shallow trench isolation (STI) structure in the semiconductor substrate; applying a first ion implantation using a mask on the semiconductor substrate to form a drift region of a second conductivity type into the semiconductor substrate with the drift region surrounding the first STI structure, wherein the second conductivity type is opposite of the first conductivity type; applying a second ion implantation using the same mask to form a first doped region in the semiconductor substrate such that the first doped region includes a first portion and a second portion that are connected, wherein the first portion is located in the drift region surrounding the STI structure, the second portion is located in the semiconductor substrate outside the drift region and under a gate structure to be subsequently formed, and a depth of the first doped region is less than a depth of the drift region; applying a counter-doping implantation using the same mask to form a counter-doped region surrounding the STI structure and having the first conductivity in the drift region, wherein a depth of the counter-doped region is less than the depth of the drift region; after forming the counter-doped region, forming a body region on one side of the drift region in the semiconductor substrate, wherein the body region has the first conductivity type; and forming the gate structure on the semiconductor substrate, wherein one end of the gate structure extends to an area on the body region another end of the gate structure extends to an area on the first STI region.