Patent ID: 8933513
Filing Date: 2015-01-13
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first semiconductor layer of a first conduction type; a second semiconductor layer of a second conduction type arranged on the first semiconductor layer; a third semiconductor layer of the first conduction type arranged on the second semiconductor layer; a fourth semiconductor layer of the first conduction type arranged on the second semiconductor layer adjacent to the third semiconductor layer, the fourth semiconductor layer having an impurity concentration lower than the impurity concentration of the third semiconductor layer; a fifth semiconductor layer of the second conduction type which extends from the region on the third semiconductor layer to the region on the fourth semiconductor layer; a first metal electrode electrically connected to the fifth semiconductor layer; and a second metal electrode electrically connected to the first semiconductor layer, the second semiconductor layer, the third semiconductor layer and the fourth semiconductor layer, the fifth semiconductor layer, the fourth semiconductor layer and the second semiconductor layer forming a parasitic bipolar transistor, the fifth semiconductor layer and the third semiconductor layer forming a parasitic diode with the breakdown voltage thereof being lower than the breakdown voltage of the parasitic bipolar transistor, at least the second semiconductor layer and the third semiconductor layer forming parasitic resistances, and the parasitic diode, the parasitic bipolar transistor and the parasitic resistances forming a protection device, in which a reverse current of the parasitic diode, having a breakdown voltage lower than the breakdown voltage of the parasitic bipolar transistor, brings the parasitic bipolar transistor into conduction by the occurrence of a snapback.