Patent ID: 8089095

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, the first semiconductor layer having a first surface that is opposite to the first surface of the semiconductor substrate and having a second doping concentration; a second semiconductor layer of the second conductivity type overlying the first surface of the first semiconductor layer, the second semiconductor layer having a first surface that is opposite to the first surface of the first semiconductor layer and having a third doping concentration; a first semiconductor region of the second conductivity type having at least a portion within the second semiconductor layer, the first semiconductor region forming a portion of a zener diode; a first blocking structure formed as a first multiply-connected domain having a first periphery and extending from the first surface of the second semiconductor layer into the first semiconductor region but not through the first semiconductor region, the first periphery surrounding at least a first portion of the second semiconductor layer; and a first diode within the first portion of the second semiconductor layer.