Heterojunction biopolar transistor and semiconductor integrated circuit device using the same

摘要

A heterojunction bipolar transistor has a raised breakdown voltage and restrains the rising characteristic of IC-VCE characteristic from degrading. The collector region includes first, second, and third collector layers of semiconductor. The first collector layer is made of a doped or undoped semiconductor in such a way as to contact the sub-collector region. The second collector layer is made of a doped or undoped semiconductor having a narrower band gap than the first collector layer in such a way as to contact the base region. The third collector layer has a higher doping concentration than the second collector layer in such a way as to be located between or sandwiched by the first collector layer and the second collector layer.