Preparation of p-n Junction Diode by B-Doped Diamond Film Grown on Si-Doped c-BN

A heterojunction diode has been fabricated by boron-doped p-type diamond thin film grown epitaxially on a silicon-doped n-type cubic boron nitride bulk crystal using the conventional hot filament chemical vapour deposition method. The ohmic electrode of Ti (50 nm)/Mo (100 nm)/Au (300 nm) for the p-type diamond film and the bulk crystal of the c-BN were deposited by the rf planar magnetron method. Then the device was annealed at 410°C in air for 1 h in order to form ohmic metal alloy. The current-voltage characteristics of the heterojunction diode were measured and the result indicated that the rectification ratio reached 105, and the turn-on voltage and the highest current were 7 V and 0.35 mA, respectively.