Diode ideality factor for surface recombination current in AlGaAs/GaAs heterojunction bipolar transistors

n-p-n AlGaAs/GaAs heterojunction bipolar transistors of various emitter areas have been fabricated to examine the diode ideality factor for surface recombination. These transistors are fabricated with and without exposed extrinsic base surfaces. Comparison of the measured results indicates that the base surface recombination current increases exponentially with the base-emitter voltage with an ideality factor which is closer to 1 than 2(1>