Patent ID: 8546917

Claim:
A semiconductor structure, comprising: a substrate layer; a buried layer formed on the substrate layer; a first well region formed on the buried layer; a second well region formed on the buried layer and adjacent to the first well region; a first doped region on the second well region; a second doped region on the first well region; a third doped region on the first well region; a fourth doped region on the second well region; an anode coupled to the first doped region, the fourth doped region, the second well region and the buried layer; and a cathode coupled to the second doped region, the third doped region and the first well region, wherein, the substrate, the first well region, the first doped region and the third doped region have a first conductivity type, the buried layer, the second well region, the second doped region and the fourth doped region have a second conductivity type opposite to the first conductivity type, the second well region, the first well region and the second doped region form a first BJT having a first element type, the first doped region, the second well region and the first well region form a second BJT having a second element type opposite to the first element type, the first BJT and the second BJT are electrically connected in parallel.