Patent ID: 8686531
Filing Date: 2014-04-01
Classification: H01L

Abstract:
1. A power semiconductor device comprising: a semiconductor body layer extending over a semiconductor substrate of a first conductivity type, the semiconductor body layer having a second conductivity type opposite the first conductivity type; a well of the first conductivity type extending in the semiconductor body layer and configured to be electrically insulated from the semiconductor substrate; at least one transistor formed in the well, the transistor comprising a source, drain, and a gate, the source comprising a first high-concentration impurity region formed in the well and the drain comprising a second high-concentration impurity region formed in the well; and a guard ring region of the first conductivity type surrounding the well but laterally separated from the well by the semiconductor body layer, wherein the guard ring region together with the semiconductor substrate and the semiconductor body layer form a parasitic bipolar transistor, and the guard ring region functions as a collector of the parasitic bipolar transistor.