Density of Traps at the Insulator/III-N Interface of GaN Heterostructure Field-Effect Transistors Obtained by Gated Hall Measurements

We apply the gated Hall method to obtain the density of trap distribution, D_it(E), at the insulator/III-N interface of a heterostructure field effect transistor. It is shown that D_it is proportional to the difference between the steady-state and the high-frequency prediction of the gate-induced two-dimensional electron gas concentrations. The Dit profile at the SiN_x/GaN interface in the energy range of 1.2-2.3 eV below the GaN conduction band is obtained as a demonstration of the method.