EARLY VOLTAGE IN HETEROJUNCTION BIPOLAR-TRANSISTORS - QUANTUM TUNNELING AND BASE RECOMBINATION EFFECTS

An extension of the thermionic emission expression for Early voltage V -A for heterojunction bipolar transistors including quantum mechanical tunneling and base recombination effects is provided. The theoretical model is based on a single flux treatment of the carrier transport in voking the concise notation of scattering matrices. V-A is numerically evaluated under the WKB quantum mechanical approximation for triangul ar and parabolic barriers. The temperature dependence of the Early vol tage is simulated numerically and compared to earlier theoretical V-A predictions and actual experimental results of V-A in heterojunction b ipolar transistors.