Patent ID: 7960198

Claim:
A method of making a semiconductor device comprising: selectively etching through a layer of p-type SiC semiconductor material on a layer of n-type SiC semiconductor material on an n-type SiC semiconductor substrate layer to expose the underlying n-type SiC semiconductor material in a central portion of the device; and selectively etching through the layer of p-type semiconductor material and the layer of n-type SiC semiconductor material to expose the underlying n-type SiC semiconductor substrate layer in a peripheral portion of the device; thereby forming a mesa structure comprising a raised region of n-type SiC semiconductor material on the n-type SiC semiconductor substrate layer having sidewalls and an upper surface and one or more discrete raised regions of p-type SiC semiconductor material on a central portion of the upper surface of the n-type SiC semiconductor material circumscribed by a continuous raised region of p-type SiC semiconductor material on a peripheral portion of the upper surface of the n-type SiC semiconductor material, wherein the continuous raised region of p-type SiC semiconductor material comprises an inner edge and an outer edge; thermally oxidizing the semiconductor device to form an oxide layer on unetched surfaces of p-type SiC semiconductor material and on etched surfaces of the semiconductor device including the sidewalls of the raised region of n-type semiconductor material and on the exposed semiconductor substrate layer; optionally forming one or more layers of dielectric material on the oxide layer; selectively etching through the oxide layer and any layers of dielectric material over the discrete p-type regions and over the continuous raised region to expose the underlying p-type SiC semiconductor material; selectively etching through the oxide layer and any layers of dielectric material over the exposed n-type SiC semiconductor material to expose the underlying n-type SiC semiconductor material in the central portion of the semiconductor device; forming ohmic contacts on the exposed p-type SiC semiconductor material of the discrete p-type regions and on the exposed p-type SiC semiconductor material of the continuous raised region of p-type semiconductor material; depositing Schottky metal on the ohmic contacts and on the exposed n-type SiC semiconductor material.