Heterojunction bipolar transistor

Abstract

A base contact layer (106) constituted by p-type GaN is formed on a base layer (104) constituted by InGaN in the periphery of an emitter layer (105) constituted by AlGaN. A base electrode (112) is formed on the base contact layer (106). Each nitride semiconductor has V group polarity due to crystal growth in the -c axis direction.

Claims

1. - A subcollector layer formed on a substrate, composed of an n-type nitride semiconductor crystal grown in the c-axis direction, - A collector layer formed on the subcollector layer, composed of n-type InGaN grown in the c-axis direction, - A base layer is formed on the collector layer and is composed of InGaN grown in the c-axis direction, with a lower In composition than the collector layer. - An emitter layer formed in contact with the base layer, which is composed of AlGaN grown in the c-axis direction, - A base contact layer made of p-type GaN grown in the c-axis direction, formed in contact with the base layer surrounding the emitter layer, - An emitter contact layer formed on the emitter layer, which is composed of an n-type nitride semiconductor crystal grown in the c-axis direction, An emitter electrode formed on the emitter contact layer, A base electrode formed on the base contact layer, A collector electrode connected to the subcollector layer, A two-dimensional hole gas formed in the base layer near the interface between the base layer and the emitter layer, and in the base layer near the interface between the base layer and the base contact layer. A heterojunction bipolar transistor equipped with [a specific feature].

2. In the heterojunction bipolar transistor according to claim 1, The base layer is p-type in part or entirely in the thickness direction. A heterojunction bipolar transistor characterized by the following features.

Images