【International Papers】Heteroepitaxial growth of Ga₂O₃ thin films on Al₂O₃(0001) by ion beam sputter deposition

      Researchers from the xxxx have published a dissertation titled "Heteroepitaxial growth of Ga₂O₃ thin films on Al₂O₃(0001) by ion beam sputter deposition " in Journal of Applied Physics.

ABSTRACT

      Deposition of epitaxial oxide semiconductor films using physical vapor deposition methods requires a detailed understanding of the role of energetic particles to control and optimize the film properties. In the present study, Ga₂O₃ thin films are heteroepitaxially grown on Al₂O₃(0001) substrates using oxygen ion beam sputter deposition. The influence of the following relevant process parameters on the properties of the thin films is investigated: substrate temperature, oxygen background pressure, energy of primary ions, ion beam current, and sputtering geometry. The kinetic energy distributions of ions in the film-forming flux are measured using an energy-selective mass spectrometer, and the resulting films are characterized regarding crystalline structure, microstructure, surface roughness, mass density, and growth rate. The energetic impact of film-forming particles on the thin film structure is analyzed, and a noticeable decrease in crystalline quality is observed above the average energy of film-forming Ga ⁺ ions around 40 eV for the films grown at a substrate temperature of 725  °C.

FIG. 1.Sketch of the IBSD setup for thin film growth and analysis of properties of film-forming species using energy-selective mass spectrometry (ESMS).

FIG. 2. Kinetic energy distributions of secondary (a) Ga⁺⁠, (b) O⁺⁠, (c) O₂⁺ ions in the reference process configuration for the oxygen ion beam sputtering of a Ga₂O₃ target, normalized by maximum. Vertical dashed lines mark the average kinetic energies.

DOI：doi.org/10.1063/5.0211179