GaN HEMT Technology Development Assessment through Nonlinear Characterization

HEMT devices based on AlGaN/GaN heterostructures exhibit constantly improving power performances. Nonlinear characterization is needed at each new device generation, both to assess the maximum power capabilities and to guide the next technological step, by highlighting open problems related to the device layout or material defects. This paper demonstrates the capabilities of the Politecnico di Torino dedicated test-set to nonlinear characterization of SELEX-SI GaN HEMTs, including the investigation of the device scaling properties and the maximum output power in different classes of operation and with several loading condition. The set-up overcomes measurements problems related to high power dissipation and device heating, high output reflection coefficients required for optimum load conditions, and the risk of device damage as a consequence of high voltage operation. The acquisition of the time-domain gate and drain waveforms together with a real-time active load-pull characterization is shown to lead to better insight into the device power performances