Patent ID: 9607980
Date: 2017-03-28
CPC Classifications: H01L

Claim:
1. A high voltage transistor, comprising: a substrate; a high voltage well, disposed in the substrate; a first base region, disposed in the high voltage well, wherein the first base region has a first conductivity type; a first doped region, disposed in the first base region, wherein the first doped region has a second conductivity type complementary to the first conductivity type; a second doped region, disposed in the high voltage well at one side of the first base region, wherein the second doped region has the second conductivity type, and the second doped region has a first doping concentration; a second base region, disposed in the high voltage well under the second doped region, and the second base region being contacted with the second doped region, wherein the second base region is contacted with the high voltage well, the second base region has the second conductivity type, the second base region has a second doping concentration, and the second doping concentration is less than the first doping concentration; and a third doped region, disposed in the high voltage well under the second base region, and the third doped region being contacted with the second base region, wherein the third doped region has the second conductivity type, the third doped region has a third doping concentration, and the third doping concentration is less than the second doping concentration.