Simulating multi-finger power HBTs

A new model of multi-finger heterojunction bipolar transistors (HBT) is presented to analyze and predict current collapse, bias dependence and output power. The simulation Of multi-finger HBTs has proven to be very challenging in both computer-aided design and electromagnetic (EM) simulation. However, by taking the biasing scheme into consideration, a successful simulation can be performed that enables the analysis of temperature and bias variations in each finger. This analysis includes self-heating, coupled thermal effects in multiple ports, current collapse and output power reduction. By incorporating multiple unit finger HBT models with a multi-port thermal network, a model is developed that enables thermal effects with DC, small-signal and large-signal simulations to be modeled in a circuit simulator.