β-Ga2O3 on Si (001) grown by plasma-assisted MBE with γ-Al2O3 (111) buffer layer: Structural characterization

beta -Ga2O3 was deposited in thin film form by plasma-assisted molecular beam epitaxy at 670 degrees C and 630 degrees C onto a gamma -Al2O3 (111) buffer layer grown at 840 degrees C by e-beam evaporation on a clean Si (001) surface. The beta -Ga2O3 film was 66 nm thick, stoichiometric, and strongly textured, as determined by x-ray reflectivity, x-ray photoelectron spectroscopy, reflection high-energy electron diffraction, x-ray diffraction, and transmission electron microscopy, with three basal growth planes (201), (101), and {310}, including one twin variant {310}. The observed basal growth planes correspond to the close-packing planes of the distorted face-centered cubic oxygen sublattice of beta -Ga2O3. Local structural ordering can be thought to occur due to a continuation of the oxygen sublattice from the gamma -alumina buffer layer into the beta -gallia film. Each beta -Ga2O3 growth plane further gives rise to 12 symmetry-derived rotational in-plane variants, resulting in a total of 48 domain variants. Atomistic models of possible gallia-alumina interfaces are presented.

Automated summary

In this study, beta-Ga2O3 thin films were grown on a silicon surface using plasma-assisted molecular beam epitaxy at different temperatures. The structural characteristics of the films were analyzed through various testing methods, and atomistic models of gallia-alumina interfaces were proposed based on the results.