Structure and method for forming a guard ring to protect a control device in a power semiconductor IC

摘要

Provided is a power semiconductor device including a guard ring region to protect control devices. The power semiconductor device includes a semiconductor body layer extending over a semiconductor substrate of a first conductivity type. The semiconductor body layer has a second conductivity type opposite the first conductivity type. A well of the first conductivity type extends in the semiconductor body layer and is configured to be electrically insulated from the semiconductor substrate. At least one control device is formed in the well, where the control device comprises at least one of PN junction. A guard ring region of the first conductivity type is laterally spaced from but surrounds the well. 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.