Diamond Schottky barrier diodes with low specific on-resistance

We have fabricated sandwich-type diamond Schottky barrier diodes with high current density on an undoped homoepitaxial diamond film grown on a heavily boron-doped type Ib diamond substrate. The current–voltage measurements for the diodes show excellent rectification characteristics in a temperature range of 298–873 K. The current density flowing through the diodes and the specific on-resistance of the diodes were 310 A cm−2, 9.68 × 10−3 Ω cm2 and 637 A cm−2, 4.71 × 10−3 Ω cm2 at 3 V forward bias at 298 K and 873 K, respectively. The activation energies of the band-gap states calculated from reverse current were around 300 meV. The capacitance–voltage measurement showed the large difference between the space charge densities of the substrate and the CVD diamond film.