Photoassisted high-frequency capacitance-voltage characterization of the Si_3N_4/GaN interface

摘要

A revised method to measure the interface state density of Si_3N_4/GaN metal-insulator-semiconductor diodes is reported. The wide band gap of GaN suppresses hole generation at room temperature and consequently allows measurements in deep depletion. Using the method outlined in this paper, the total interface state density can be measured throughout the bandgap above the bias in deep depletion utilizing an above bandgap light source. We report a peak interface state density of 5.0 × 10~(12) cm~(-2) eV~(-1) at ～0.3 eV using this procedure, whereas the Terman method reports a peak of <2×10~(11) cm~(-2) eV~(-1) for the same Si_3N_4/GaN metal-insulator-semiconductor diode without illumination.