Patent ID: 8390071

Claim:
An electrostatic discharge protection (ESD) clamp having a predetermined threshold voltage Vt 1 , comprising: a bipolar transistor having a first surface and underlying the first surface having a base of a first conductivity type, a base contact of the first conductivity type extending into the base from the first surface, an emitter of a second, opposite, conductivity type extending into the base from the first surface and laterally separated from the base contact at the first surface by a distance Lbe, and a collector proximate the base; wherein the base comprises a first base portion containing the base contact and the emitter and having a first base dopant concentration, a second base portion located laterally between the first portion and a first boundary and having a second base dopant concentration, and a third base portion of width D located laterally between the boundary and a portion of the collector and having a third base dopant concentration, wherein the threshold Vt 1 is determined at least in part by the width D; wherein the first base dopant concentration is less than the second base dopant concentration; and wherein Lbe is in the range of about 0.7 to 23 micrometers.