Temperature dependence of current gain of InGaP/InGaAsN/GaAs heterojunction bipolar transistors

Abstract

The temperature effect on current gain is presented for InGaP/InGaAsN/GaAs heterojunction bipolar transistors (HBTs) including as-grown and annealed HBTs. The annealed HBT was annealed before device fabrication at 700 °C for 30 sec. Experimental results showed that the current gains of the annealed HBT increase with the increase of temperature in the temperature range of –20–100 °C . The smaller the collector current, the larger is the positive differential temperature coefficient. At high current levels, the current gain dependence on temperature is significantly reduced. On the other hand, a negative coefficient is observed in the as-grown HBT in all current range. This finding indicates that the annealed InGaP/InGaAsN/GaAs HBT is better candidate than the as-grown InGaP/InGaAsN/GaAs HBT for power devices. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)