Patent ID: 7196375

Claim:
A high-voltage MOS transistor comprising: a substrate; a gate structure overlying the substrate, the gate structure having a first side and a second side opposite to the first side; a first doping region with a first dosage formed in the substrate on the first side of the gate structure and partially covered by the gate structure; a second doping region with a second dosage formed within the first doping region adjacent to the edge on the first side of the gate structure to serve as a drain region and a third doping region with the second dosage formed in the substrate adjacent to the edge of the second side of the gate structure to serve as a source region; and a channel region formed in the substrate between the first and third doping regions by turning on the high-voltage MOS transistor to pass current between the source and drain regions, where a resistance per unit length of the channel region is substantially equal to a resistance per unit length of the first doping region, wherein the first dosage is about 7.0 to 9.0E12 ions/cm 2 .