Measurement of electron saturation velocity in Ga0.52In0.48P in a double heterojunction bipolar transistor

The electron saturation velocity in Ga0.52In0.48P has been measured as a function of temperature, utilizing the Kirk effect in double heterojunction bipolar transistors. An AlGaAs base was used to eliminate the conduction band spike, and measurements were carefully performed using pulse biasing to minimize self-heating. Voltage drops across the base and collector series resistances were also taken into account. The measured room temperature saturation velocity of 5.0×106 cm/s decreased rapidly to 2.9×106 cm/s at 200 °C. These results provide useful data for modeling and design, and are particularly important for the prediction of frequency performance of Ga0.52In0.48P/(Al)GaAs/Ga0.52In0.48P double heterojunction bipolar transistors when operating at typical elevated temperatures in power applications.