Patent ID: 8058703

Claim:
A semiconductor transistor device comprising: a drift region including a first lateral portion having a first dopant concentration and a second lateral portion having a second dopant concentration that is higher than the first lateral portion; an insulating structure formed on the drift region and disposed over a border between the first and second lateral portions; a gate insulator formed on an exposed portion of the first lateral portion; a gate electrode formed on the gate insulator and a first surface of a portion of the insulating structure also having a second surface abutting the first portion of the drift region; a source disposed toward the first lateral portion of the drift region; a drain disposed toward the second lateral portion of the drift region; and an additional N-type drift portion of the drift region, formed in the second lateral portion toward the drain, wherein the insulating structure abuts the first and second lateral portions of the drift region, the additional N-type drift portion, and said drain of the transistor device.