Fabrication of Diamond-Like Carbon Film

We are developing an electron emitter device of a polycrystalline diamond film for cathode and a diamond-like carbon film for insulator. The insulation of the DLC films used for the previous devices was not sufficient. The purpose is to improve the insulation of DLC films. A required performance for the device is below 0.15mA/cm2 at more than 50V. Diamond-Like Carbon films are fabricated by a high frequency plasma CVD method, and the insulation of the films was evaluated. Materials gas of benzene (C6H6) was flowed into a chamber, pressure was 5Pa, HF power was 100W (13.56MHz), and deposition duration was 10 - 60 seconds, the substrates were n-type silicon wafer. The thickness of DLC films was 50nm - 170nm. A coating of gold electrode is vacuum evaporated over both the DLC film and silicon wafer. The current-voltage characteristic between the electrodes was measured. The shottkey characteristic can be ascertained from the I-V curve. The insulation at low voltage was sufficient, however, the leak current increased up to 2.7mA/cm2 at 40V. It is necessary to improve the insulation at the high voltage.