Method for forming termination structure for gallium nitride Schottky diode

摘要

A termination structure for a nitride-based Schottky diode includes a guard ring formed by an epitaxially grown P-type nitride-based compound semiconductor layer and dielectric field plates formed on the guard ring. The termination structure is formed at the edge of the anode electrode of the Schottky diode and has the effect of reducing electric field crowding at the anode electrode edge, especially when the Schottky diode is reverse biased. In one embodiment, the P-type epitaxial layer includes a step recess to further enhance the field spreading effect of the termination structure.

主权项

1. A method for forming a nitride-based Schottky diode, comprising:
providing a nitride-based semiconductor body of a first conductivity type; forming a nitride-based epitaxial layer of a second conductivity type, opposite the first conductivity type, on a front side of the nitride-based semiconductor body; forming a first dielectric layer on the nitride-based epitaxial layer; etching the first dielectric layer and the nitride-based epitaxial layer to the nitride-based semiconductor body to define an opening for an anode electrode of the nitride-based Schottky diode; forming a step recess in the nitride-based epitaxial layer, the part of the nitride-based epitaxial layer having a thinner thickness is disposed towards the opening for the anode electrode of the Schottky diode; forming a first metal layer on the front side of the nitride-based semiconductor body to form a Schottky junction at the exposed top surface of the semiconductor body, the first metal layer forming the anode electrode of the Schottky diode; and providing a cathode electrode in electrical contact with the nitride-based semiconductor body, wherein the nitride-based epitaxial layer forms a guard ring and the first dielectric layer forms a dielectric field plate, the guard ring and the dielectric field plate together forming a termination structure for the Schottky diode, and the termination structure being configured to reduce electric field crowding at the edge of the anode electrode.