[WeB2] Thin Film Growth of Oxides

11:15 AM - 11:30 AM JST(2:15 AM - 2:30 AM UTC)

[WeB2-04] Development of Rhombohedral (InxGa1-x)2O3 on c-Sapphire Using α-Ga2O3 Buffer Layer by Mist Chemical Vapor Deposition

〇Sohaib Hassan¹, Abhay Kumar Mondal¹, Kun Liu¹, Htet Su Wai ¹, Toshiyuki Kawaharamura¹ (1. Kochi University of Technology (Japan))

Rhombohedral In2O3 (rh-In2O3) is a metastable transparent conductive oxide material that is difficult to grow directly on c-plane sapphire due to large lattice mismatch and structural incompatibility. In this study, an corundum structure α-Ga2O3 buffer layer was employed to enable low-temperature epitaxial growth of rh-In2O3 using mist chemical vapor deposition (mist CVD). Mist CVD is a cost-effective, easy-to-operate, and solution-based method for the growth of oxide thin films. The α-Ga2O3 buffer layer was deposited at 375°C, providing a structurally compatible template for subsequent In2O3 growth. Rh-In2O3 films were grown from temperatures 400°C to 450°C at 25°C. X-ray diffraction (XRD) and ellipsometry were used to evaluate structural quality and thickness. XRD results at a temperature of 425°C confirmed the (0006) high crystalline phase of corundum-structured rh-In2O3 peak at 2θ = 37.2° on sapphire using an α-Ga2O3 buffer layer. However, the growth at higher temperatures led to degradation in crystallinity. These results demonstrate that the α-Ga2O3 buffer layer effectively overcomes lattice mismatch and enables low-temperature growth of rh-In2O3 on sapphire by the mist CVD method. This cost-effective mist CVD approach provides a practical pathway for developing the corundum-structured transparent conductive oxide material for applications in transparent electronics and optoelectronic devices.