Patent ID: 8110448

Claim:
A method of forming an ESD device comprising: providing a semiconductor substrate having first and second surfaces; forming an isolation layer on the first surface of the semiconductor substrate, the isolation layer having a first surface that is opposite to the first surface of the semiconductor substrate; forming a conductor layer on the first surface of the isolation layer and having a first surface that is opposite to the first surface of the semiconductor layer wherein the isolation layer inhibits current flow from the conductor layer into the semiconductor substrate; forming a semiconductor layer of a first conductivity type on the first surface of the conductor layer, the semiconductor layer having a first surface that is opposite to the first surface of the conductor layer wherein the conductor layer conducts current from the semiconductor layer laterally through the conductor layer; forming a first semiconductor region positioned between a first portion of the semiconductor layer and the first surface of the conductor layer; forming a first blocking structure extending from the first surface of the semiconductor layer into the semiconductor substrate wherein a periphery of the blocking structure surrounds at least a first portion of the semiconductor layer; forming a plurality of diodes in the first portion of the semiconductor layer wherein a portion of the plurality of diodes overlays the first semiconductor region; and forming a conductor extending from the semiconductor layer into the semiconductor substrate to provide an electrical connection to the semiconductor substrate wherein the conductor is external to the periphery of the first blocking structure.