Bipolar transistor with improved low temperature current gain.

摘要

A bipolar transistor with improved low temperature current gain comprises an emitter region (32) of a first conductivity type; a collector region (16) of said first conductivity type; and a base region (26) of a second conductivity type opposite said first type sandwiched between said emitter region and said collector region. Said base region (26) is doped with a first and second impurity of said second conductivity type, said second impurity having a higher ionization energy than said first impurity. There is provided a high doping level base that increases bandgap narrowing without decreasing freeze-out activation energy. The second impurity freezes out sooner than the first impurity resulting in the freeze-out activation energy being equal to or greater than the energy with only the first impurity. <IMAGE>