Characterization of MOCVD-grown AlSiO gate dielectric on β-Ga2O3 (001)

The interface and bulk properties of aluminum-silicon-oxide (AlSiO) dielectric grown by metal-organic chemical vapor deposition (MOCVD) on (001) β-Ga2O3 were investigated systematically using a deep UV-assisted capacitance–voltage methodology. The improved surface preparation with a combination of UV-ozone and wet chemical treatment reduced near-interface traps resulting in a negligible hysteresis. An average interface state density of 6.63 × 1011 cm−2 eV−1 and AlSiO bulk trap density of 4.65 × 1017 cm−3 eV−1 were quantified, which is half of that for Al2O3 deposited by atomic layer deposition (ALD). A net positive interface fixed charge of 1.56 × 1012 cm−2 was measured. In addition, a high dielectric breakdown field of ∼7.8 MV/cm and more effective suppression of gate leakage were achieved on these devices compared with ALD-Al2O3 on similar metal-oxide-semiconductor (MOS) structures.