Patent ID: 8354698

Claim:
A semiconductor device, comprising: a substrate; a first well, a second well and a third well, located at a top side of the substrate and separated from each other, the first well located between the second well and the third well; a first doping region, a second doping region, a third doping region and a fourth doping region, the first doping region formed in the substrate and located between the first well and the third well, the second doping region formed in the first well, the third doping region formed in the second well, the fourth doping region formed in the substrate and located at a bottom side of the substrate; a polysilicon layer, formed above the substrate and located above a gap between the second doping region and the third doping region; and a first electrode, a second electrode, a third electrode and a fourth electrode, the first electrode electrically connected to the polysilicon layer, the second electrode electrically connected to the fourth doping region, the third electrode electrically connected to the third well, the second doping region and the third doping region, and the fourth electrode electrically connected to the first doping region; wherein, the doping type of the substrate, the first doping region, the second doping region, the third doping region, and the fourth doping are the same and complementary to that of the first well, the second well and the third well.