A study of electrical characteristics of Gd2O3/GaN and Gd2O3/AlGaN/GaN MOS Heterostructures

Abstract

In this paper, we present the electrical properties of hexagonal Gd2O3 grown epitaxially on GaN/Si(111) and AlGaN/GaN/Si(111) virtual substrates. GaN and AlGaN/GaN heterostructures were grown on Si(111) substrates by plasma assisted molecular beam epitaxy (PA-MBE). A 12 nm thick Gd2O3 film was deposited by the pulsed laser ablation (PLA) technique. Platinum is deposited on Gd2O3 in order to make the Schottky contacts, and the resulting Pt/Gd2O3/GaN and Pt/Gd2O3/AlGaN/GaN metal-oxide semiconductor (MOS) contacts are noted to exhibit rectifying behavior. The electrical characterizations are carried out in a certain frequency range by the conventional capacitance-voltage (C-V) and conductance-voltage (Gp/ω-V) measurement techniques. Pt/Gd2O3/AlGaN/GaN shows lower hysteresis than Pt/Gd2O3/GaN as observed from the C-V measurements. The interface trap density and respective time constant are calculated from the conductance-voltage measurements at corresponding applied bias. Finally, it is concluded that Gd2O3 on III-nitrides is a potential candidate for high power applications in radio frequency range.