Patent ID: 7622788

Claim:
A GaN heterojunction bipolar transistor with a p-type strained InGaN base layer, comprising: a substrate; a highly doped collector contact layer, located over the substrate; a low doped collector layer, located over the collector contact layer; a p-type base layer, located over the collector layer; a highly doped p-type strained InGaN base layer, located directly on a top surface of the p-type base layer and covering the whole top surface of the p-type base layer; an emitter layer, located over the highly doped p-type strained InGaN base layer; a highly doped emitter contact layer, located over the emitter layer; and an emitter metal electrode, a base metal electrode, a collector metal electrode, respectively located on the emitter contact layer, the p-type strained InGaN base layer and the collector contact layer.