Patent ID: 6448160
Filing Date: 2002-09-10
Classification: H01L

Abstract:
A method of fabricating a semiconductor rectifier device comprising the steps of:a) providing a semiconductor substrate of first conductivity type and having opposing major surfaces, b) selectively doping regions in a first major surface with dopant of second conductivity type to form a guard ring of second conductivity type around a device region, c) forming a silicon oxide layer over the device region, d) forming a doped polysilicon layer over the silicon oxide layer, e) selectively forming a dopant mask material over areas of the doped polysilicon layer where device channel regions are to be formed, f) removing the exposed doped polysilicon layer and the underlyling silicon oxide layer from the device region thereby forming gate electrodes overlying gate silicon oxide under the dopant mask, g) doping the exposed first major surface with a dopant of first conductivity type to form source/drain regions, the dopant being insufficient to convert the guard ring to first conductivity type, h) etching the dopant mask to expose peripheral portions of the gate electrode, i) doping the major surface under the exposed peripheral portion of the gate electrode with dopant of the second conductivity type to form a body region of second conductivity type and channel region which abuts the source/drain regions, j) forming a first electrode over the first major surface interconnecting the guard ring, gate, and source/drain regions, and h) forming a second electrode over the second major surface contacting the substrate.