Growth of gallium oxide thin films from gallium acetylacetonate by atomic layer epitaxy

Abstract

Gallium oxide thin films have been deposited by atomic layer epitaxy (ALE) using Ga(acac)₃(acac = pentane-2,4-dionate) and either water or ozone as precursors. Films were grown on silicon (100), soda lime and Corning glass substrates. The influence of the deposition parameters (e.g. pulse duration, growth and source temperatures) on film growth were studied and by a proper choice of the parameters a self-controlled growth was demonstrated around 370°C. Spectrophotometry, X-ray diffraction (XRD), Rutherford back-scattering spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS) were used to determine the refractive index, thickness, crystallinity and stoichiometry of the films. All the films were amorphous and highly uniform with only small thickness variations. The films deposited with water contained a considerable amount of carbon as an impurity whereas ozone as an oxidizer gave stoichiometric Ga₂O₃ films.