Heterojunction-type bipolar transistor with ballast resistance layer

US5721437A · kind A · utility

Assignee

• SHARP KABUSHIKI KAISHA · JP

Inventors

• John Twynam · Regensburg, DE
• Motoji Yagura · Nara, JP
• Toshiyuki Shinozaki · Tenri, JP
• Toshiaki Kinosada · Izumi, JP

Key dates

• Filing date: Aug 23, 1995
• Grant date: Feb 24, 1998
• Expiry date: Aug 23, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D10/821

Abstract

A heterojunction type AlGaAs/GaAs bipolar transistor includes an n-GaAs collector layer, a p.sup.+ -GaAs base layer and an n-Al.sub.x Ga.sub.1-x As emitter layer formed in a stack, and an n-Al.sub.y Ga.sub.1-y As ballast resistance layer formed on the emitter layer. The ballast resistance layer has an Al concentration y in the range of 0<y<0.4, and a resistance higher than that of the emitter layer.