Patent ID: 6927141

Claim:
A reduced mask process for forming a fast recovery diode comprising the steps of forming a field oxide body atop a surface of a semiconductor die; applying a first mask to said field oxide body and etching a large area window therein exposing a portion of said surface of said die and leaving an outer oxide termination ring around said exposed portion; defining a large area P/N junction in said die below said exposed portion; applying a second mask to clear said exposed portion for the application of an anode contact; evaporating platinum metal on an opposing surface of said die and heating said die to drive platinum atoms into said die; depositing metal atop said exposed portion and over the oxide termination ring; and applying a third mask to etch said metal to define an anode contact which overlies said exposed portion and the inner periphery of said termination ring and a separate EQR ring which overlies the outer periphery of said termination ring.