Simulation of electrical characteristics of InP double-heterojunction bipolar transistors with InGaAsSb base

We study the effect of antimony (Sb) content in the InGaAsSb base layer of InP double-heterojunction bipolar transistors (DHBTs), under the condition of lattice match, by using a two-dimensional device simulator Medici. Careful calibration of physical parameters is first done to ensure that the simulation result matches data measured from a reference device. When the composition of Sb in the InGaAsSb base region is varied, the conduction band offset (ΔE_C), effective density of states in conduction band and valence band (N_C, N_V), bandgap energy (E_G), and intrinsic carrier concentration (n_i) are changed accordingly. These semiconductor material parameters are considered in the simulation to compare the electrical characteristics of the DHBT. In addition to the Sb composition, different materials of In_0.52Al_0.48As or InP in the emitter are simulated. The study on Sb content in the base and the heterostructure of E-B junction helps the development and optimization of InGaAsSb DHBTs.