Evaluation of the impact of the external collector resistance on results from parameter scaling for heterojunction bipolar transistors

It is demonstrated that the external collector resistance, representing the voltage drop from the collector terminal to the internal collector node, and the corresponding time constant can have a large impact on the extraction of geometry scalable compact model parameters for bipolar transistors. Furthermore, the accuracy of two widely used extraction methods is evaluated based on data obtained from 2D numerical device simulation and a compact model for transistors with different emitter widths.