【Epitaxy Papers】Epitaxial growth of single-crystalline (0002) BeO film on (-201) β-Ga2O3 substrate

      Researchers from the Yonsei University have published a dissertation titled "Epitaxial growth of single-crystalline (0002) BeO film on (-201) β-Ga₂O₃ substrate" in Applied Surface Science.

Abstract

      Addressing the persistent challenges of heterostructure integration and low thermal conductivity in β-Ga₂O₃ devices, we report the epitaxial growth of single-crystalline BeO thin films on (-201) β-Ga₂O₃ substrates via plasma-enhanced atomic layer deposition. X-ray diffraction confirms the epitaxial growth of wurtzite (0002) BeO films with well-defined out-of-plane and in-plane alignments, despite the dissimilar crystal structures. High-resolution transmission electron microscopy and fast Fourier transform analyses reveal a sharp BeO/β-Ga₂O₃ interface and coherent crystallographic alignment. X-ray photoelectron spectroscopy demonstrates type-II band alignment with a valence-band offset of –0.5 eV and a conduction-band offset of 4.4 eV, distinct from the type-I alignment observed in non-epitaxial BeO/(001) β-Ga₂O₃ heterostructures. Electrical characterization shows that a Mo/(0002) BeO/(-201) β-Ga₂O₃ MOS capacitor exhibits an exceptionally low leakage current density of 5.92 × 10^-10A cm⁻² at 1 MVcm⁻¹ and minimal frequency dispersion in capacitance–voltage data, underscoring the excellent insulating properties and interface quality of epitaxial BeO films. This new route for epitaxial BeO growth on (-201) β-Ga₂O₃ holds strong promise for next-generation β-Ga₂O₃ heterostructure-based power electronics and ultraviolet optoelectronic devices.

DOI：

https://doi.org/10.1016/j.apsusc.2025.165719