【Epitaxy Papers】Low temperature growth of high-quality Ga₂O₃ films on MgO substrate via atomic layer deposition

      Researchers from the Xi'an University of Posts & Telecommunications and Xidian University have published a dissertation titled "Low temperature growth of high-quality Ga₂O₃ films on MgO substrate via atomic layer deposition" in Materials Science and Engineering: B.

Abstract

      Ga₂O₃ is an ultrawide-band-gap semiconductor, which performs good application prospect in the power devices and solar-blind photodetectors. MgO (100) is usually acted as the heteroepitaxial substrate because of the rather low lattice mismatch with Ga₂O₃ films. However, conventional film deposition methods typically require high growth temperatures. In this paper, high-quality Ga₂O₃ films are prepared on MgO (100) substrate through atomic layer deposition (ALD) method at the low temperature of 350 °C. The films exhibit a preferred (100) orientation, which are achieved through a temperature-induced phase transition from the metastable γ-phase to the stable β-phase. The structural characteristics of the β-Ga₂O₃ films using PE-O₂ or O₃ as oxygen source are similar with each other, which present small full width at half maxima (FWHM) of 0.060° for the (600) plane rocking curve and low surface roughness of only 0.187 nm at 350 °C. After annealing at 700 °C, the crystalline quality and surface morphology of the β-Ga₂O₃ films on MgO substrate are both further improved slightly. Two types of atomic configurations are also constructed to simulate the lattice matching of epitaxial β-Ga₂O₃ films on MgO (100) substrate. The results are beneficial for the applications of Ga₂O₃-based electronic and photoelectron devices on MgO substrates especially at the low-temperature condition.

DOI：

https://doi.org/10.1016/j.mseb.2026.119535