Ga₂O₃, like SiC and GaN, is a wide-bandgap material with excellent material characteristics, and extensive research on heteroepitaxy using various substrates is actively underway. In this study, we used a metal-organic chemical vapor deposition (MOCVD) method to grow Ga₂O₃ thin films on Ti and Ni substrates, commonly employed as electrodes. The Ga₂O₃ thin films were grown within the temperature range of 450 °C to 650 °C, and the characteristics of the thin films were evaluated according to the substrate type and growth temperature. Both substrates form flat amorphous surfaces at low growth temperatures, while rough crystalline structures form as the growth temperature increases. In addition, electrodes were deposited on all substrates on which Ga₂O₃ films were grown, and the current-voltage (I-V) and capacitance-voltage (C-V) characteristics were evaluated. In current-voltage results, both substrates exhibited increased operating voltages as the growth temperatures increased in the range of 450 °C and 550 °C. However, at temperatures of 600 °C and above, Ti substrates displayed leakage current paths, while Ni substrates showed minimal current flow. In capacitance-voltage results, Ti and Ni substrates exhibited decreasing capacitance values with increasing growth temperature. Additionally, it was found that various factors affect the electrical characteristics of both substrates. Furthermore, the observed high operating voltage is anticipated to be effectively utilized in TVS and varistor components.

Keywords: Ga₂O₃, MOCVD, metal substrate, TVS, varistor.