Method of fabricating power rectifier device to vary operating parameters and resulting device

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.