A compact model for the cutoff frequency in high speed bipolar transistors

A compact physical model for high speed bipolar junction transistors (BJT) in integrated rf-circuits is presented. The model, which suits both homo-and heterojunction devices, is based on the de Graaf-Kloosterman formalism for the modelling of BJTs, but adds important heterostructure device physics and incorporates also the physical properties of the SiGe material. The model implemented in APLAC circuit simulator, shows good agreement between the simulation results and measured data both for pure silicon BJTs and for SiGe-base heterojunction transistors.