Two-Tone Distortion Modeling for SiGe HBTs Using the High-Current Model

摘要

This paper examines certain aspects of the base resistance model of Hicum-2.1 (High Current Model) to address convergence problems seen during two-tone distortion simulations of SiGe HBTs. We propose some changes to the Rbi model implementation so as to limit the conductivity modulation factor from assuming unphysical values and implement them into the ADS simulator. This eliminated the convergence problems and resulted in an improvement in the simulation time. Simulations are performed through the RF Design Environment (RFDE) and excellent agreement between the inter-modulation distortion measurements and the model is observed. Model extraction methodology and correlation with measurement results for DC, f_T and distortion for a 200 GHz SiGe HBT process are discussed.