Patent ID: 8304856
Filing Date: 2012-11-06
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate of a first general conductivity type; an epitaxial layer of a second general conductivity type formed on the semiconductor substrate; a first buried layer of the second general conductivity type buried in the semiconductor substrate; a second buried layer of the second general conductivity type buried in the first buried layer and having a higher impurity concentration than the first buried layer; a third buried layer of the first general conductivity type buried in the second buried layer and the epitaxial layer; a first conductive layer of the first general conductivity type formed in a first portion of the epitaxial layer so as to be on a peripheral portion of the third buried layer; and an isolation layer of the first general conductivity type formed in the epitaxial layer so as to isolate the first portion of the epitaxial layer and the third buried layer from other portions of the epitaxial layer, wherein the semiconductor substrate and the first buried layer are configured to operate as a first diode so that the semiconductor substrate works as an anode and the first buried layer works as a cathode, the first conductivity layer and the epitaxial layer are configured to operate as a second diode so that the first conductive layer works as an anode and the epitaxial layer works as a cathode, and the first diode and the second diode are connected serially.