TEMPERATURE-DEPENDENCE OF DC AND RF CHARACTERISTICS OF ALINAS/GAINAS HBTS

Device characteristics of compositionally graded AlInAs/GaInAs heterojunction bipolar transistors have been measured and analyzed from cryogenic temperatures up to 250-degrees-C. Excellent stability in dc and RF performance is observed at elevated temperatures, desirable for high-speed and high-density integrated circuit applications. DC current gain exhibits about 10% variation over the entire measured temperature range. F(T) and f(max) at 125-degrees-C decreased by approximately 10% from their room-temperature values while improving steadily when device was cooled down to near-liquid-helium temperature. The common-emitter breakdown voltage, BV(CEO), is 8.0 V at room temperature and reduces to 7.5 V at 125-degrees-C. Likewise, the collector-base breakdown voltage, BV(CBO), and the base-emitter breakdown voltage, BV(EBO), reduce by about 0.5 V over the same temperature range. The breakdown voltages increase significantly at cryogenic temperatures. The low turn-on voltage and excellent low-temperature characteristics make the AlInAs/GaInAs HBT attractive for cryogenic applications.