Patent ID: 8252656

Claim:
A method for forming an electrostatic discharge (ESD) protection clamp, comprising: providing a supporting substrate having therein a semiconductor layer of a first conductivity type extending to a first surface of the substrate; forming a well region of the first conductivity type in a first portion of the semiconductor layer and extending to the first surface; forming a doped region of a second, opposite, conductivity type in the semiconductor layer extending substantially to the first surface and laterally spaced apart from the well region by a second portion of the semiconductor layer; providing a mask layer having a portion of a predetermined width overlying part of the second portion of the semiconductor layer, the portion of the mask layer having a first edge facing toward the well region and a second edge facing toward the doped region; using the portion of the mask layer, providing a still further doped region of the first conductivity type having a first portion ohmically coupled to the well region and a first distal edge substantially determined by the first edge of the mask portion; and using the portion of the mask layer, providing an additional doped region of the second conductivity type having a first portion ohmically coupled to the doped region and a second distal edge substantially determined by the second edge of the mask portion.