An Electrothermal Model for Empirical Large- Signal Modeling of AlGaN/GaN HEMTs Including Self-Heating and Ambient Temperature Effects
Accurate modeling of electrothermal effects of GaN electronic devices is critical for reliability design and assessment. In this paper, an electrothermal model for large signal equivalent circuit modeling of AlGaN/GaN HEMTs including self-heating and ambient temperature effects is presented. To accurately describe the effect of ambient temperature, two separate electrothermal networks (Idiss, Rdiss, and Cdiss for self-heating, and Iamb, Ramb, and Camb for ambient temperature effect) are used to describe drain-source current slump due to self-heating and ambient temperature effects, respectively. A temperature-dependent thermal resistance and thermal capacitance model is proposed and implemented in the electrothermal network. The extraction of the thermal parameters is fulfilled by using numerical finite-element method. Single tone on wafer load-pull measurements at two operating frequencies (3 and 14 GHz) are carried out for verification purposes. The results show that good agreements on fundamental output power, the second and third harmonics output power, and power added efficiency have been achieved between simulations and measurements over a wide range of -55 °C to 175 °C.