Patent ID: 9018071
Filing Date: 2015-04-28
Classification: H01L

Abstract:
1. A method for forming an electrostatic discharge protection (ESD) clamp, comprising: providing a semiconductor substrate of a first conductivity type and having an upper surface; forming at least one transistor having a first well region of a first conductivity type and first doping density extending into the substrate from the first surface, the first well region having a first lateral edge; forming, in the at least one transistor, another well region of a second opposite conductivity type extending into the substrate from the first surface, the another well region forming part of a collector of the transistor and having another lateral edge laterally separated from the first lateral edge by a distance D adapted to determine in part a threshold voltage Vt forming in the first well region a base contact of the first conductivity type and an emitter of the second conductivity type separated by a lateral distance Lbe; and wherein the first doping density and the lateral distance Lbe are selected to provide a parasitic base-emitter resistance Rbe in the range of 1<Rbe<800 Ohms.