Low Interface Trapped Charge Density for AlO/β-GaO (001) Metal-Insulator-Semiconductor Capacitor

Abstract

In this letter, high-performance Al2O3/β-Ga2O3 (001) metal-insulator-semiconductor (MIS) capacitor has been demonstrated. The capacitance-voltage (C.V) curves of the Al2O3/β-Ga2O3 (001) MIS capacitor remain stable under different measurement frequencies. The leakage current density is lower than 2.0 × 10-8 A/cm2 when the gate voltage is in the range of –5 13 V. The fixed charge and trapped charge densities in Al2O3 film are 4.4 × 1012 and 6.0 × 1011 cm-2, respectively. Average and minimum interface trapped charge density (Dit) for Al2O3/β-Ga2O3 (001) interface has been extracted to be as low as 3.3 × 1011 and 2.3 × 1011 cm-2 eV-1 via the Terman method, respectively. The low Dit is probably attributed to the modification of vacancy defects and the introduction of hydroxyl groups at the Al2O3/β-Ga2O3 (001) interface after piranha solution pretreatment for β-Ga2O3.