Patent ID: 7986011
Filing Date: 2011-07-26
Classification: H01L

Abstract:
1. An electrostatic discharge protection device provided in a semiconductor substrate of a second semiconductor type, the electrostatic discharge protection device comprising: a source region and a drain region of a first semiconductor type, a gate region extending over a first well region of the second semiconductor type, the first well region being provided in between the source region and the drain region, a second well region of the first semiconductor type under the source region and under the drain region, the first well region being provided in between the second well region under the source region and the second well region under the drain region, a first buried region of the second semiconductor type under the first well region, a second buried region of the first semiconductor type under the second well region, wherein the first and the second buried regions have a higher doping level than the first and the second well regions; and the electrostatic discharge protection device further comprising three parallel parasitic bipolar lateral transistors, a first one of the transistors having a base formed by the first well region, having an emitter formed by one of the source and drain regions and having a collector formed by the other one of the source and drain regions, a second one of the transistors having a base formed by the first well region, having an emitter formed by a first part of the second well region and having a collector formed by a second part of the second well region, and a third one of the transistors having a base formed by the first buried region, having an emitter formed by a first part of the second buried region and having a collector formed by a second part of the second buried region.