Patent ID: 8759913

Claim:
A double diffused drain metal oxide semiconductor (DDDMOS) device formed in a first conductive type substrate, wherein the substrate has an upper surface, the DDDMOS device comprising: a second conductive type drift region formed beneath the upper surface, the drift region including a first region and a second region; a gate formed on the upper surface, wherein the first region is located beneath the gate; a second conductive type source and a second conductive type drain formed at two sides of the gate beneath the upper surface respectively, wherein the drain is located in the second region, and the drain and the gate are separated by part of the second region from top view; a dielectric layer formed on both the gate and the second region; and a conductive layer formed on the dielectric layer, which overlaps at least part of the second region between the gate and the drain from top view; wherein the conductive layer extends across a device region in a width direction perpendicular to a channel direction of the DDDMOS device from top view, wherein the device region is defined by a field oxide layer surrounding the DDDMOS device.