Electrical characterization of GaN metal oxide semiconductor diode using Sc₂O₃ as the gate oxide

GaN metal oxide semiconductor diodes were demonstrated utilizing Sc₂O₃ as the gate oxide. Sc₂O₃ was grown at 100°C on MOCVD grown n-GaN layers in a molecular beam epitaxy (MBE) system, using a scandium elemental source and an Electron Cyclotron Resonance (ECR) oxygen plasma. Ar/Cl₂ based discharges was used to remove Sc₂O₃, in order to expose the underlying n-GaN for ohmic metal deposition in an Inductively Coupled Plasma system. Electron beam deposited Ti/Al/Pt/Au and Pt/Au were utilized as ohmic and gate metallizations, respectively. An interface trap density of 5 × 10¹¹ eV^-1 cm^-2 was obtained with the Terman method. Conductance-voltage measurements were also used to estimate the interface trap density and a slightly higher number was obtained as compared to the Terman method. Results of capacitance measurements at elevated temperature (up to 300°C) indicated the presence of deep states near the interface.