Patent ID: 8039359

Claim:
A method of forming an ESD device comprising: providing a semiconductor substrate of a first conductivity type and having a first peak doping concentration; forming a first semiconductor region of a second conductivity type and at least approximately the first peak doping concentration wherein the first semiconductor region forms a first P-N junction with the semiconductor substrate; forming an epitaxial layer on the first semiconductor region wherein the epitaxial layer has the second conductivity type and a second peak doping concentration; forming a first doped region of the first conductivity type on the epitaxial layer and overlying the first semiconductor region; forming a first isolation trench extending vertically from a top surface of the epitaxial layer through the first semiconductor region and into the semiconductor substrate wherein the first isolation trench extends laterally around an outside perimeter of the first doped region; and forming a second doped region of the second conductivity type on the epitaxial layer and overlying a portion of the semiconductor substrate but not overlying the first semiconductor region.