A NEW LARGE-SIGNAL HBT MODEL

Several effects important for large signal operations of heterojunctio n bipolar transistor (HBT's) were not included in the previous HBT mod els used in most commercial circuit simulators. Exclusion of these eff ects resulted in large discrepancies between modeled and measured devi ce characteristics. This paper presents a new large signal HBT model w hich takes into account those important effects for the device operati on. The effects have been identified from measured device characterist ics and can be justified from first principles. To make it easy to use , the model is made up of the elements available from SPICE, During th e course of the model development, an extraction procedure for the mod el parameters has been established to minimize the uncertainty of the extracted parameter values. The new model has been applied to HBT's wi th various emitter sizes and excellent agreement has been achieved bet ween modeled and measured data over a wide range of bias conditions an d signal frequencies.