Thermal modeling of RF FinFET PAs through temperature-dependent X-parameters extracted from physics-based simulations

FinFET RF technology is increasingly investigated for the deployment of 5G communication systems and beyond. Thermal management represents one of the main problems that must be addressed for the successful design of FinFET-based microwave power amplifiers. In fact, the peculiar 3D device structure inhibits the efficient heat dissipation through the substrate, requiring an accurate temperature-dependent nonlinear device model. In this paper we extract the FinFET X-parameters from accurate temperature dependent physics-based simulations. The T -dependent X-parameters are then included into Keysight ADS using a dedicated isolated port to represent the device junction temperature. With this modeling approach, we present the T -dependent analysis of a low-power FinFET amplifier at 70 GHz, showing that with T increasing from 300 K to 390 K we have more than 15% P sat loss, 2 dB gain degradation and 10 percentage points efficiency loss.