Bipolar transistors

摘要

A base region and a collector region of a bipolar transistor are interconnected through a hetero junction and forbidden band gap of the collector region is larger than that of the base region. When the transistor is made of a silicon base material, the collector region is made of oxygen containing polycrystalline silicon or amorphous silicon, whereas when made of a GaAs base alloy, the collector region is made of a mixed crystal of GaAs-AlAs.