【Epitaxy Papers】The Influence of Amorphous-to-Crystalline Transition on the Structural and Optical Properties, and Wet Etching Behavior of MOCVD-Grown Ga₂O₃ Thin Films

      Researchers from the National Korea Maritime and Ocean University have published a dissertation titled "The Influence of Amorphous-to-Crystalline Transition on the Structural and Optical Properties, and Wet Etching Behavior of MOCVD-Grown Ga₂O₃ Thin Films" in Micro and Nanostructures.

Abstract

      Amorphous Ga₂O₃ thin films were deposited by metal-organic chemical vapor deposition and subsequently annealed to investigate the effects of crystallization on their structural, optical, and chemical properties. X-ray diffraction and atomic force microscopy analyses confirmed that crystallization initiates above 700 °C and that a β-Ga₂O₃ phase forms after annealing. The optical bandgap and Urbach energy were determined using ultraviolet–visible spectroscopy and spectroscopic ellipsometry. As the annealing temperature increased, the bandgap increased from 4.85 eV to 5.02 eV, while the Urbach energy decreased from 479 meV to 219.6 meV, indicating enhanced structural order. In wet etching experiments using a buffered oxide etchant, amorphous films exhibited etch rates of 12–17 nm/min. The activation energy was determined to be 0.627 eV, suggesting a reaction-limited mechanism. In contrast, crystallized films showed negligible etching, indicating high chemical stability and potential applications in selective etching and etch-stop layer processes.

DOI：

https://doi.org/10.1016/j.micrna.2025.208403