Patent ID: 7683427

Claim:
A laterally diffused metal-oxide-semiconductor (LDMOS) device, comprising: a semiconductor substrate; a source region comprising a source doping region and a first doping region encompassed by a body region formed in the semiconductor substrate; a drain region formed in the semiconductor substrate; a first field oxide layer formed on a drift region in the semiconductor substrate between the source region and the drain region and on a side of the drain region; a gate structure formed on the semiconductor substrate between the source region and the drain region with one side laterally extending onto a part of the first field oxide layer and the opposite side beside the source doping region; and a gate dielectric layer formed between the gate structure and the semiconductor substrate, wherein the gate dielectric layer comprises a first portion having a first thickness and a second portion having a second thickness greater than the first thickness, the first portion and the second portion are arranged in a lateral direction, the second portion borders the first field oxide layer, and the second portion of the gate dielectric layer is over a border between the body region and the semiconductor substrate.