ELECTRICAL-PROPERTIES OF A SCHOTTKY-BARRIER FORMED ON A HOMOEPITAXIALLY GROWN DIAMOND(001) FILM

The electrical properties of Schottky barriers formed on homoepitaxial ly grown diamond (001) films has been studied by means of current-volt age (I-V) and capacitance-voltage (C-V) measurements. From the I-V cha racteristics, it is found that the Schottky-barrier height of the as-g rown film depends strongly on the work function or the electronegativi ty of the metal while that of the oxidized film is almost independent of the metal. This result implies that the mechanisms of the barrier f ormation on the as-grown surface are drastically changed by oxidation. A difference between the electrical properties of the as-grown film a nd those of the oxidized film is also observed from C-V measurements. The high density of space charge due to ionized gap states is found in the vicinity of the as-grown diamond film and disappears after oxidat ion. These results suggest the presence of new acceptor centers, which are not related to boron, in the hydrogenated diamond.