Kink and Cathodoluminescence in AlGaN/GaN HEMTs

In this paper we present a detailed characterization of kink effects in AlGaN/GaN HEMTs. Our data suggest that kink is due to a shift in the device pinch-off voltages resulting from electron trapping in the GaN buffer layer. The presence of the kink is fully correlated with the appearance of the ???yellow luminescence??? broad peak in cathodolumine-scence spectra taken on the device active area, thus confirming that cathodoluminescence and photolumi-nescence spectroscopy may represent valuable techniques for the screening of this parasitic effect.