Electrostatic discharge protection circuit

Abstract

An electrostatic discharge (ESD) protection structure comprises a high voltage P type implanted region disposed underneath an N+ region. The high voltage P type implanted region and the N+ region form a reverse diode or a Zener diode depending on different doping densities. The ESD protection structure further comprises a plurality of P+ and N+ regions. The high voltage P type implanted region and the P+ and N+ regions form a semiconductor device having a breakdown characteristic. In one embodiment, the semiconductor device may be a bipolar PNP transistor. The bipolar PNP transistor and a Zener diode in series connection form an ESD protection circuit. In another embodiment, the semiconductor device may be a Silicon-Controlled Rectifier (SCR), which is series-connected with a reverse diode. Both embodiments provide a reliable ESD protection.

Dependencies are inferred from the claim text.