Inversion behavior in thermally oxidized p-GaN metal–oxide–semiconductor capacitors

The characteristics of thermally oxidized p-GaN metal–oxide–semiconductor (MOS) capacitors fabricated on sapphire substrates have been investigated electrically. 100-nm-thick β-Ga2O3 was grown by thermal dry oxidation of Mg-doped GaN at 880 °C for 5 h. Capacitance–voltage measurements at room temperature show a low interface trap density of ∼1×1010 eV−1 cm−2 and display peculiar behavior that is different from a deep depletion feature. These results indicate some possibilities of surface inversion in thermally grown β-Ga2O3/p-GaN MOS structures without any n+ source regions.