Electric properties of metal/diamond interfaces utilizing hydrogen-terminated surfaces of homoepitaxial diamonds

As-grown homoepitaxial diamond surfaces fabricated by chemical vapor deposition are terminated by hydrogen, and are expected to have a low density of surface states. On such diamond surfaces, high-quality Schottky contacts have been obtained utilizing metals with low electronegativities, such as A1 or Pb. The ideality factors of those point contacts to diamond are less than 1.1, which is the nearest value to unity ever reported in diamonds. Quantitative measurements of Schottky barrier heights at various metal contacts have also been performed. A strong correlation between the barrier heights and the metal electronegativities is observed. Even an ohmic property is obtained when metals with higher electronegativities were used. The effect of Fermi level pinning is reduced at the interfaces between metals and hydrogen-terminated diamonds.