Patent ID: 8835975
Filing Date: 2014-09-16
Classification: H01L

Abstract:
1. A breakover diode device comprising: a P type layer of substrate semiconductor material; an anode metal electrode disposed on a bottom surface of the P type layer of substrate semiconductor material; an N type buffer layer of epitaxial semiconductor material disposed on the P type layer, wherein the N type buffer layer has a N type dopant concentration of at least 1×10 an N− type base layer of epitaxial semiconductor material disposed on the N type buffer layer, wherein the N− type base layer is less than 130 microns thick; a P type base region that extends from a semiconductor surface down into the N− type base layer to a depth, wherein the P type base region has a peripheral edge at the semiconductor surface, wherein the peripheral edge has a minimum radius of curvature that is at least twice the depth; an N+ type annular emitter region that extends down from the semiconductor surface down into the P type base region, wherein P type semiconductor material of the P type base region extends up to the semiconductor surface and defines a cathode short region of P type semiconductor material that is laterally surrounded at the semiconductor surface by the N+ type annular emitter region, wherein the cathode short region has a width at the semiconductor surface, and wherein the width of the cathode short region is less than 0.250 millimeters; a cathode metal electrode disposed over part of the annular N+ type emitter and over the cathode short region at the semiconductor surface; and a floating metal ring disposed on the P type base region, wherein the floating metal ring surrounds the cathode metal electrode at the semiconductor surface, wherein the floating metal ring does not contact any part of the N+ type emitter region, and wherein the floating metal ring does not contact any part of the N− type base layer.