【Others Papers】Micromechanical Properties of β-Ga₂O₃ Single Crystal By Instrumented Indentation and Scratch Tests

      Researchers from the Wuxi Vocational Institute of Commerce have published a dissertation titled "Micromechanical Properties of β-Ga₂O₃ Single Crystal By Instrumented Indentation and Scratch Tests" in ECS Journal of Solid State Science and Technology.

Abstract

      Gallium oxide (β-Ga₂O₃), as a representative fourth-generation semiconductor material, exhibits exceptional physical properties. However, it’s challenging to achieve high-quality wafer surfaces of β-Ga₂O₃ crystal due to its inherent cleavability. To provide theoretical guidance for the surface machining of such cleavable materials, this study systematically investigated the micro/nano-mechanical properties of β-Ga₂O₃ crystal by integrating first-principles calculations with nanoindentation/micro-scratch testing. First-principles calculations were employed to analyze the atomic structure and cleavage behavior of β-Ga₂O₃, revealing that the [GaO₆] octahedron is more prone to disruption than the [GaO₄] tetrahedron, which explains why cleavage delamination occurs on the (100)A and (100)B planes. Combining the elastic parameters obtained from first-principles calculations with nanoindentation experimental results, the following values were obtained: shear modulus (G) of 76 ± 13 GPa, bulk modulus (B) of 168.5 ± 0.5 GPa, elastic modulus (E) of 197.5 ± 28.5 GPa, hardness (H) of 8.5 ± 2.5 GPa, and a Poisson’s ratio (v) of 0.305 ± 0.025. Based on nanoindentation energy analysis, linear elastic fracture mechanics (LEFM) theory, and three distinct equivalent strain energy density (ESEL) theories, the fracture toughness (K_c) of β-Ga₂O₃ crystal was calculated to be approximately 1.87 MPa·m^1/2. The K_c calculation method derived from LEFM theory is particularly well-suited for exfoliation-prone brittle crystalline materials.

DOI：

https://doi.org/10.1149/2162-8777/ae4b68