This PhD work focuses on the evaluation of performance and reliability of GaN HEMTs under RF operation and associated integrated circuits. The objective is to define a methodology to establish a dynamic safe operating area (SOA) for these devices in order to identify their operational limits. Key questions addressed include: what is the maximum load cycle ensuring reliable amplifier operation, and do RF stress conditions trigger the same degradation mechanisms as DC stress? The methodology relies on three steps: nonlinear large-signal simulations of waveform dynamics, RF waveform characterization on a dedicated IMS/NANOCOM test bench, and accelerated RF aging experiments. By correlating static and pulsed I-V characterizations with RF power and waveform evolutions, the physical origin of degradation can be localized. The final outcome will contribute to improving lifetime prediction methods for RF GaN circuits.
