Spiral hollow cathode plasma .. assisted diamond deposition

High quality diamond films have been deposited on silicon and sapphire by means of a combined hot filament/electron beam/plasma‐assisted chemical vapor deposition technique. A spiral tantalum foil is used as the hot cathode to generate a high‐current dc discharge at a low sustaining voltage. Gas mixtures consisting of methane, hydrogen, and argon flowing through the spiral cathode towards the anode are effectively decomposed by the hot cathode and the high‐density plasma. Diamond particles and films, grown at a rate between 0.5 and 5 μm/h, have been characterized by scanning electron microscopy, x‐ray diffraction, and Raman spectroscopy.