Apparatus for low-temperature growth of diamond-containing films

Abstract

In current processes of diamond growth, the substrate temperature is in general around 600–900 °C. In the case of diamond-like carbon, the substrate temperature is lower, around 25–200 °C. There are many superior properties of diamond compared with diamond-like carbon; however, the high temperature requirement to grow diamond precludes many technologically important substrate materials such as zinc sulfide for an infrared window or electronic devices on which protective diamond layers are to be coated. The present approach is a hot filament DC glow discharge of hydrocarbon gases. A graphite hot filament cathode is inserted in a discharge cylinder tube anode. The discharge voltage is in the range of 50 to 250 volts at a methane gas pressure of about 100 microns. A negative biased voltage of 100 volts is applied between the cathode and the substrate. A magnetic field of 1 kG is applied near the cathode-anode assembly. At a substrate temperature of 200–400 °C, the deposited film on silicon crystal is confirmed by an electron diffraction pattern to consist of microcrystalline diamond.