Physical heterojunction bipolar transistor model for microwave large signal simulation

A new physical large signal HBT model is proposed in this contribution. To our knowledge it is the first time that a physical large signal HBT model is implemented into a circuit simulator. The new HBT model describes the transistor action of the intrinsic HBT by an analytic formulation based on physical principles. The core of this model comprises emitter, base and collector layers, the corresponding model parameters are given by material and design data. It is shown that a one dimensional description of the core including an equation for the power balance of the transistor is sufficient to describe the self-heating effect in the dc range as well as the junction temperature under large signal conditions. The extrinsic regions of the HBT are modelled by an equivalent circuit with passive elements. The values for these parasitic elements are given by material data and by an extraction method based on measured characteristics.