Reliable Ohmic Contact Properties for Ni/Hydrogen-Terminated Diamond at Annealing Temperature up to 900 °C

Ohmic contact with high thermal stability is essential to promote hydrogen-terminated diamond (H-diamond) based electronic devices for high-temperature applications. Here, Ohmic contact characteristics of Ni/H-diamond at annealing temperature up to 900 ℃ are investigated. The measured current-voltage curves and deduced specific contact resistance ( ) are used to evaluate the quality of contact properties. Schottky contacts are formed for the as-received and 300 ℃-annealed Ni/H-diamond. When the annealing temperature is increased to 500 ℃, Ohmic contact properties are formed with the of 1.5×10-3 Ω cm2 for the Ni/H-diamond. As the annealing temperature rises to 900 ℃, the is determined to be as low as 6.0 ×10-5 Ω cm2. It is believed that the formation of Ni-related carbides at the Ni/H-diamond interface promotes the decrease of . The Ni metal is extremely promising to be used as Ohmic contact electrode for H-diamond-based electronic devices at temperature up to 900 ℃.