Patent ID: 7345341

Claim:
A semiconductor device capable of high-voltage operation, comprising: a substrate comprising a first well formed therein; a gate stack overlying the substrate, wherein the gate stack comprises a gate dielectric layer that maintains a uniform thickness and a gate electrode formed thereon; a channel well and a second well formed in portions of the first well, located on opposite sides of the gate stack; a source region formed in a portion of the channel well; a drain region formed in a portion of the second well; and an oxide portion formed in an end of the gate electrode layer and disposed on a portion of the gate dielectric layer adjacent to the drain region; wherein the first well and the second well is formed with a conductivity type opposite to that of the substrate, the channel well is formed with a conductivity type the same as that of the substrate; wherein a thickness of the oxide portion increases progressively to the end of the gate stack adjacent to the drain region.