A Geometry Scalable Approach to InP HBT Compact Modeling for mm-Wave Applications

The bias and frequency dependent scaling of InP/InGaAs HBTs with emitter width (and length) has been investigated for a 300GHz foundry process. It was found that the currents, capacitances and resistances related to the emitter dimensions scale quite well. This allows the use of special test structures in combination with geometry variations to distinguish different physical effects and to accurately determine the external elements of the transistor as well as the thermal resistance independently of each other. The approach enables the generation of a geometry scalable set of HICUM/L2 model parameters for a large geometry range. The model was compared to experimental DC, AC and large-signal data of devices with different emitter geometry. The good agreement offers a much wider range of options for optimizing high-speed InP circuits.