Electrical properties of thermally oxidized p-GaN metal–oxide–semiconductor diodes

We report on the electrical properties of thermally oxidized p-GaN metal–oxide–semiconductor (MOS) diodes with n+ source regions fabricated on sapphire substrates. The n+ regions were selectively produced in Mg-doped GaN by Si+N coimplantation and subsequent annealing at 1300 °C, and then 100-nm-thick β-Ga2O3 was grown by dry oxidation at 880 °C for 5 h. Capacitance–voltage measurements at room temperature display a surface inversion feature with an onset voltage of ∼2.5 V and show an extremely low interface trap density less than 1×1010 eV−1 cm−2. These results suggest that the thermally grown β-Ga2O3/p-GaN MOS structure is a promising candidate for inversion-mode MOS field-effect transistors.