MEASURING THE JUNCTION TEMPERATURE OF ALGAAS/GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS USING ELECTROLUMINESCENCE

Rises in the junction temperatures of heterojunction bipolar transistors (HBTs) due to self-heating effects during transistor operation are measured using the electroluminescence of the band-to-band recombination. This method is useful for the direct junction temperature monitoring of small geometry devices. Junction temperatures measured in AlGaAs/GaAs HBTs with five 2 X 20 mum2 emitter fingers are raised 115-degrees-C when the product of the collector current and the emitter-collector voltage is 0.25 W. The thermal resistance is determined to be 260-degrees-C/W at 300 K.