Chapter 4 - Other Reactors

Abstract

This Chapter describes hot filament and DC plasma chemical vapor deposition (CVD) reactors that areused for oriented growth of diamond. In the hot filament CVD (HFCVD) reactor, there are filaments of tungsten (W) or tantalum (Ta), which are heated up to 2000 to 2200°C. They are placed at 5 to 10mm above the substrate. In this reactor, CH4 and H2 molecules that have touched the hot filament are thermally dissociated to be fragmented hydrocarbons and atomic hydrogen. They diffuse onto the substrate to create diamonds. In DC Plasma CVD reactor, a negative DC bias voltage is applied to the cathode, as the gas pressure and the energy density in the plasma are so high that a growth rate of 10μm/h can be achieved.