Other

Hitachi, Ltd.

Hitachi Device Engineering Co., Ltd.

Reiko Hayami

Masao Kondo

Katsuyoshi Washio

Hiromi Shimamoto

Katsuya Oda

Eiji Oue

Masamichi Tanabe

A bipolar transistor is provided which is of high reliability and high gain, and which is particularly suitable to high speed operation. The bipolar transistor operates with high accuracy and with no substantial change of collector current even upon change of collector voltage. It also has less variation than conventional bipolar transistors for the collector current while ensuring high speed properties and high gain. In one example, the band gap in the base region is smaller than the band gap in the emitter and collector regions. The band gap is constant near the junction with the emitter region and decreases toward the junction with the collector region. A single crystal silicon/germanium is a typically used for the base region.

Heterojunction bipolar transistor

Growing community of inventors

Kokubunji, Japan

Reiko Hayami