Base profile tail effects on the low temperature operation of silicon bipolar transistors

This paper reports new results on bandgap narrowing in self aligned polysilicon emitter bipolar transistors. Using temperature dependent current gain measurements, we show that the tail region of the implanted base plays a dominant role in the effective bandgap narrowing of the base. This result will be very important for the development of pseudo-heterojunctions and low temperature-operation bipolar transistors.