Temperature-Dependent Interface-State Response in an Al₂O₃/n-GaN Structure

With a combination of the static capacitance–voltage ( C – V ) and the capacitance transient ( C – t ) methods, the interface-state response in an Al 2 O 3 /n-GaN structure was investigated at temperatures ranging from 23 to 300 °C. We observed pronounced degradation of the static C – V curves measured at high temperatures, arising from the enhancement of charging/discharging rates of interface states at deeper energies within the bandgap of GaN. Faster responses with larger magnitudes also appeared in the time-dependent capacitance at high temperatures. From a simple analysis of the C – t results, we estimated the capture cross section of the states to be on the order of 10 -19 cm 2 .