Patent ID: 7384826

Claim:
A method for fabricating a semiconductor device, comprising the steps of: forming a field oxide atop an upper surface of a semiconductor body along a termination region; etching a plurality of windows within said field oxide thereby forming spaced field oxide rings, said plurality of windows extending to said upper surface of said body; forming components of the semiconductor device in said upper surface of said semiconductor body; using said windows to form guard rings of P type conductivity within said upper surface of said body and further forming an oxide layer over each guard ring; etching a window within each of said oxide layers to expose said underlying guard ring; forming separate stepped field plates over each of said field oxide rings, wherein each field plate contacts either an anode contact metal or a guard ring; depositing on a back surface of said semiconductor body a metallic donor layer that includes atoms capable of forming an intermetallic composition having low contact resistivity; heating said semiconductor body thereby forming an intermetallic region of low contact resistivity in said back surface of said body; and depositing a contact metal over said intermetallic region thereby forming an ohmic contact.