Heterojunction bipolar transistor with a base layer that contains bismuth

摘要

A heterojunction bipolar transistor (HBT) with improved characteristics is provided. A III-V compound semiconductor having Bi added thereto is used for a base layer of a GaAs-based or InP-based HBT. For example, a GaAs-based HBT is formed by successively stacking a subcollector layer made of n⁺-GaAs, a collector layer made of n^--GaAs, a base layer made of p⁺-GaAsBi, an emitter layer made of n-InGaP, a first cap layer made of n-GaAs, and a second cap layer made of n⁺-InGaAs on a substrate 1 made of single crystal GaAs.