Spatial location of the E c -0.6 eV electron trap in AlGaN/GaN heterojunctions

Deep trap spectra in AlGaN/GaN high electron mobility transistor (HEMT) structures were studied by capacitance deep level transient spectroscopy. A major trap with an ionization level near E-c-0.6 eV was detected and attributed to states in the GaN buffer close to the AlGaN interface. These states have a signature very similar to the previously reported traps in AlGaN/GaN HEMTs responsible for the device degradation under electric stress. (C) 2014 American Vacuum Society.