A laterally diffused metal-oxide-semiconductor (LDMOS) device as well as a method of making the same is disclosed. A gate is formed on a semiconductor substrate between a source region and a drain region with one side laterally extending onto a part of a field oxide layer and the opposite side beside the source region. A gate dielectric layer is formed between the gate and the semiconductor substrate, wherein the gate dielectric layer comprises two or more portions having different thicknesses arranged laterally in a way that the thicknesses of the portions gradually increase from one side beside the source doping region to the opposite side bordering the field oxide layer. With such structure, the hot carrier impact is minimized and the gate length can be scaled down to gain Idlin.