Patent ID: 8896024

Claim:
An electrostatic discharge protection structure, comprising: a first well region of a first conductivity type disposed in a substrate; a second well region of a second conductivity type disposed in the substrate and adjacent to the first well region; a first doped region of the first conductivity type disposed in the first well region; a second doped region of the second conductivity type disposed in the first well region, wherein a diode is formed between the second doped region and the first doped region, and the second doped region, the first well region, and the second well region form a first bipolar junction transistor electrically connecting to the diode; a third doped region of the first conductivity type disposed in the first well region and extending into the second well region, wherein the second doped region is disposed between the first doped region and the third doped region; a fourth doped region of the first conductivity type disposed in the second well region, wherein the fourth doped region, the second well region, and the first well region form a second bipolar junction transistor; and a fifth doped region of the second conductivity type disposed in the second well region, wherein the fourth doped region is disposed between the third doped region and the fifth doped region, wherein the first doped region is electrically connected to a first electrode of the electrostatic discharge protection structure, the fourth doped region and the fifth doped region are electrically connected to a second electrode of the electrostatic discharge protection structure, and a contact window is not disposed on the second doped region.