Characterization of non-stoichiometric Ga2O3-x thin films grown by radio-frequency powder sputtering

Abstract

We report the synthesis and characterization of non-stoichiometric Ga2O3-x thin films deposited on sapphire (0001) substrates by radio-frequency powder sputtering. The chemical and electronic states of the non-stoichiometric Ga2O3-x thin films were investigated. By sputtering in an Ar atmosphere, the as-grown thin films become non-stoichiometric Ga2O2.7, due to the difference in sputtering yield between Ga and O species of the Ga2O3 target. The electronic states of the thin films consist of ~85% Ga3+ and ~15% Ga1+, corresponding to Ga2O3 and Ga2O, respectively. The films have the electrical characteristics of a semiconductor, with electrical conductivity of approximately 5.0 × 10-4 S cm-1 and a carrier concentration of 4.5 × 1014 cm-3 at 300 K. © 2020 Elsevier Ltd and Techna Group S.r.l.