Properties of gallium oxide thin films grown by ion beam sputter deposition at room temperature

Gallium oxide thin films were grown by ion beam sputter deposition (IBSD) at room temperature on Si substrates with systematically varied process parameters: primary ion energy, primary ion species (O-2(+) and Ar+), sputtering geometry (ion incidence angle alpha and polar emission angle beta), and O-2 background pressure. No substrate heating was applied because the goal of these experiments was to investigate the impact of the energetic film-forming species on thin film properties. The films were characterized with regard to film thickness, growth rate, crystallinity, surface roughness, mass density, elemental composition and its depth profiles, and optical properties. All films were found to be amorphous with a surface roughness of less than 1 nm. The stoichiometry of the films improved with an increase in the energy of film-forming species. The mass density and the optical properties, including the index of refraction, are correlated and show a dependency on the kinetic energy of the film-forming species. The ranges of IBSD parameters, which are most promising for further improvement of the film quality, are discussed. Published under an exclusive license by the AVS.

Automated summary

In this study, gallium oxide thin films were grown on Si substrates at room temperature using ion beam sputter deposition (IBSD). The impact of various process parameters on the film properties was investigated. It was found that higher energy film-forming species resulted in improved film stoichiometry and correlated with higher mass density and better optical properties.