Abstract：We investigate the influence of interface charge on electrical performance of NbAlO/AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs). Through C–V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2×1013 cm?2 exists at the NbAlO/AlGaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43×1013–1.14×1013 cm?2eV?1 is obtained at the NaAlO/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.
2015, Vol. 32 
