TCAD simulation and assessment of anomalous deflection in measured S-parameters of SiGe HBTs in THz range

Abstract

In this paper, we have assessed the RF measurements of SiGe HBTs upto 500 GHz using TCAD simulation for the first time. In order to bring confidence in simulation, the device geometries and doping profiles are captured in the simulation deck. Then all the basic DC and RF properties are calibrated with the measured data for two different geometries. Additionally the simulated unilateral gain and small signal current gain are also brought in agreement with the corresponding measured data at different bias voltages for both the devices. Finally bias and frequency dependent S- parameter measurements are compared with the TCAD simulation and resulting issues are discussed.