Plasma-based edge terminations for gallium nitride power devices

1. A method of treating a GaN power device comprising a p-GaN layer, the method comprising:

covering a portion of the p-GaN layer with a metal layer;

exposing the p-GaN layer to a hydrogen plasma;

thermally annealing the p-GaN layer, thereby passivating a region of the p-GaN layer proximate the metal layer; and

covering an additional portion of the p-GaN layer with an additional metal layer separated from the metal layer on a surface of the p-GaN layer,

wherein thermally annealing the p-GaN layer comprises passivating a region of the p-GaN layer between the metal layer and the additional metal layer.

2. The method of claim 1 , wherein thermally annealing the p-GaN layer comprises heating the p-GaN layer to a temperature in a range between 350° C. and 500° C.

3. The method of claim 1 , wherein passivating the p-GaN layer comprises passivating all of the p-GaN layer into highly resistant-GaN (HR-GaN).

4. The method of claim 3 , wherein the HR-GaN is an edge termination for the GaN power device.

5. The method of claim 1 , wherein the metal layer is in the form of a metal circle, and the additional metal layer is a metal ring surrounding the circle.

6. The method of claim 5 , wherein passivating the region of the p-GaN layer proximate the metal layer comprises passivating a region between the metal circle and the metal ring.

7. The method of claim 6 , wherein the region between the metal circle and the metal ring is a guard ring.

8. The method of claim 7 , wherein a width of the guard ring is in a range between 3 μm and 10 μm.

9. The method of claim 8 , further comprising additional guard rings, and wherein a spacing between two of the guard rings is in a range between 0.5 μm and 2 μm.

10. The method of claim 1 , wherein the GaN power device comprises a GaN p-n diode.