Patent ID: 8723264

Claim:
An ESD device comprising: a semiconductor substrate of a first conductivity type and having a first doping concentration, the semiconductor substrate having first and second surfaces; a first semiconductor layer of a second conductivity type on the first surface of the semiconductor substrate, wherein the first semiconductor layer has a first surface that is disposed between the first surface of the semiconductor substrate and a second surface of the semiconductor layer, and wherein the first semiconductor layer has a second doping concentration; a first semiconductor region of the second conductivity type positioned between a first portion of the first semiconductor layer and the first surface of the semiconductor substrate, the first semiconductor region forming a zener diode with dopants of the semiconductor substrate; a first P-N diode formed in the first semiconductor layer and overlying a first portion of the first semiconductor region; a first isolation trench extending from the second surface of the first semiconductor layer into a portion of the first semiconductor region, the first isolation trench forming a closed structure that surrounds the first P-N diode and a second portion of the first semiconductor layer overlaying the first semiconductor region; and a second P-N diode formed in the first semiconductor layer and laterally displaced from the first semiconductor region, wherein the second P-N diode is external to the first isolation trench.