SiGe HBT compact modeling for extreme temperatures

Analog and RF design building blocks for space applications require very accurate prediction of SiGe HBT device behavior in this extreme environment. The ability of two industry standard bipolar compact models to represent the SiGe HBT in an extreme temperature environment was evaluated. It was determined that neither the Mextram or VBIC industry standard models were able to accurately represent the SiGe HBT´s device performance over the extreme cold temperature environment. For initial design work a model binning approach was taken, where multiple models were required to represent the SiGe HBT over the full cryogenic temperature range. Each of the industry compact models was fitted over a limited temperature range. As the temperature range decreased the accuracy of the model decreased.