Physics-based large-signal heterojunction bipolar transistor model for circuit simulation

Abstract

A comprehensive single heterojunction bipolar transistor (HBT) model suited for circuit simulation is presented. The model is developed in the Gummel-Poon homojunction bipolar transistor model tradition, but adds important heterostructure device physics as well as physical properties of 3 or 4 compound materials such as AlGaAs and GaAs. In contrast to the existing HBT models, which use the Gummel-Poon model and fit HBT experimental data by optimising a large pool of parameters extracted from HBT measurements, the present physics-based model requires only the knowledge of the device make-up (such as the doping concentration and layer thickness) and the material parameters (such as the energy bandgap and electron affinity). Comparisons between the model and measured dependencies for AlGaAs/GaAs/GaAs HBTs on important device specifications such as the DC current/voltage characteristics, DC current gain, and cutoff frequency are included.