Influence of deep levels on the performance of AlGaInP/GaAs heterojunction bipolar transistor

We have studied deep levels in AlGaInP emitter of AlCaInP/GaAs heterojunction bipolar transistor by deep-level transient spectroscopy and photoluminescence (PL) methods. Two deep levels were obtained with thermal activation energies of E-c - E-t1 = 0.42 eV and E-c - E-t2 = 0.59 eV, whose capture cross sections are 6.27 x 10(-17) cm(2) and 6.49 x 10(-20) cm(2), where E-t1 and E-t2 are Si-related and O-related deep levels, respectively. The relationship between excitation power and PL peak intensity have revealed that nonradiative recombination centers of deep levels exist in AlGaInP. The current gain of AlGaInP/GaAs HBT decreases due to the existence of deep levels in AlGaInP.