Metalorganic vapor phase epitaxy of high-quality GaAs0.5Sb0.5 and its application to heterostructure bipolar transistors

We report the growth and characterization of high-quality InP/GaAs0.5Sb0.5/ InP heterostructures and their application to double-heterojunction bipolar transistors (DHBT). The GaAs0.5Sb0.5 layer quality was evaluated by high-r esolution x-ray diffraction (XRD), low-temperature photoluminescence (PL), and atomic force microscopy (AFM). The observed 4.2 K PL linewidth was 7.7 meV and XRD rocking curves matched those of dynamical scattering simulation s. In contrast to previously reported InP/GaAs0.5Sb0.5/InP DHBTs, the prese nt devices show nearly ideal base and collector currents, low turn-on and c ollector offset voltages, and a high current gain. Self-aligned DHBTs exhib it a cutoff frequency over 75 GHz and common-emitter current gain greater t han 100 at 300 K. (C) 1999 American Institute of Physics. [S0003-6951(99)00 207-7].