Patent ID: 8765609

Claim:
A method of forming a tapered field plate dielectric region in a semiconductor wafer, the method comprising: etching a trench in the semiconductor wafer, wherein the trench has a sidewall; depositing a first thickness of a first insulating layer on the semiconductor wafer, including the sidewall; etching a first amount of the first insulating layer, wherein a first upper portion of the first insulating layer adjacent to the top of the trench is removed to expose a first upper surface of the first insulating layer; depositing a second thickness of a second insulating layer on the semiconductor wafer, wherein the second insulating layer overlaps a portion of the first insulating layer, and wherein the second insulating layer overlaps the first upper surface; and etching a second amount of the second insulating layer, wherein a second upper portion of the second insulating layer on the sidewall of the trench is removed.