BIPOLAR TRANSISTORS

摘要

A base region and a collector region of a bipolar transistor are interconnected through a hetero junction with the forbidden band gap of the collector region being larger than that of the base region. A semiconductor region having the same conductivity type as the collector region but a lower impurity concentration than the collector region is interposed between the base region and the collector region. The semiconductor region has the same forbidden band gap as 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 an base alloy, the collector region is made of a mixed crystal of GaAs - A?As. With this construction it is possible to reduce saturation voltage and power loss at the time of conduction.