Patent ID: 8575691

Claim:
A lateral-diffusion metal-oxide semiconductor (LDMOS) device, comprising: a semiconductor substrate; at least one gate structure disposed on surface of the semiconductor substrate; a first well having a first conductive type, disposed in the semiconductor substrate adjacent to one side of the gate structure; a first isolation structure disposed in an upper portion of the first well and under a portion of the gate structure; a drain region disposed in the first well; a second isolation structure disposed in the semiconductor substrate adjacent to another side of the gate structure; a second well having a second conductive type, disposed in the semiconductor substrate between the second isolation structure and the gate structure; a source region disposed in the second well; and a deep well having the first conductive type disposed in the semiconductor substrate, wherein the deep well comprises a first region having the first conductive type and a second region having the first conductive type, the doping concentration of the first region is substantially the same as the doping concentration of the second region, wherein the first region is disposed under the first isolation structure and the first well, and wherein the second region is disposed under the second isolation structure and a portion of the second well, and the doping concentration of the deep well is less than the doping concentration of the first region and the second region.