Patent ID: 7804106

Claim:
A nitride semiconductor structure comprising on a substrate: an n-type collector layer; a p-type base layer formed over said n-type collector layer, wherein said p-type base layer is p-type InGaN; an n-type emitter layer formed directly on a first portion of a top surface of said p-type base layer; an indium-containing p-type nitride semiconductor layer formed directly on a second portion of said top surface of said p-type base layer, wherein said n-type emitter layer is not formed on the second portion, and said indium-containing p-type nitride semiconductor layer has an indium mole fraction that is higher than an indium mole fraction of said p-type InGaN base layer, and does not contact said n-type emitter layer; and a base electrode formed over said indium-containing p-type nitride semiconductor layer.