Investigation into trapping modes and threshold instabilities of state-of-art commercial GaN HEMTs

This work is aimed at investigating the performance and reliability limits of a commercially available state-of-the-art RF GaN HEMT technology. Measurement strategies to recognize and assess trap-induced degradations, prevalent in mature technologies, are discussed. Double pulsed measurements are used to capture and quantify threshold instabilities, and their evolution with temperature, for short quiescent near-threshold and off-state stress conditions. A versatile transient measurement technique evaluates threshold voltage fluctuations in the 10 μs–100 s temporal range, during stress or recovery phases, for different trap-filling configurations. Corresponding recovery transients between 27 °C to 130 °C are analysed to extract a trap activation energy of 0.53–0.56 eV for this technology. Finally, drain and gate step-stress tests are performed, providing an overview into the robustness of the gate contact under high electric fields.