The characteristics of an interesting InP/InGaAs double heterojunction bipolar transistor (DHBT) with an InAlGaAs/InP composite collector structure were demonstrated and studied. Experimentally, the operation regime was wider than 11 decades in magnitude of collector current density (10(-6) - 10(5) A/cm(2)). As compared to previous reports, the studied device exhibited a relatively larger Early voltage, smaller base-collector reverse saturation current, I-CBO, smaller multiplication factor, M-1, and smaller electron impact ionization, alpha. Moreover, the device studied also showed a relatively weaker temperature dependence on the electron impact ionization, alpha. Consequently, the DHBT device offers promise for low-voltage and low-power circuit applications. (c) 2007 The Electrochemical Society.