Thermal stability investigation for Ohmic contact properties of Pt, Au, and Pd electrodes on the same hydrogen-terminated diamond

Here, thermal stabilities for Ohmic contact properties of Pt, Au, and Pd on the same hydrogen-terminated diamond (H-diamond) epitaxial layer are investigated. A long-term annealing process is performed with annealing temperature and time of 400 °C and 8 hours, respectively. Before annealing, good Ohmic contact properties are observed for only two contacts of Pt/H-diamond and Pd/H-diamond with their specific contact resistivity (ρ_C) values of 2.7 × 10‒3 and 2.6 × 10‒4 Ω cm2, respectively. After the long-term annealing, all of three contacts on the H-diamond show good Ohmic contacts properties. The ρ_C values for the Pt/H-diamond and Au/H-diamond are 3.1 × 10‒2 and 4.2 × 10‒4 Ω cm2, respectively. They are higher than that of the Pd/H-diamond (1.1 × 10‒4 Ω cm2). Therefore, the low ρ_C and good thermal stability for the Pd/H-diamond are achieved. This is meaningful to push forward the development of H-diamond-based electronic devices for high-temperature applications.