Growth of diamond thin films by spiral hollow cathode plasma-assisted chemical vapor deposition

A direct current spiral hollow cathode which combines hot-filament, electron-beam, and plasma-assisted chemical vapor deposition mechanisms has been developed to grow diamond crystallites and continuous thin films from CH ₄/H₂ [/Ar] gas mixtures. A comprehensive study of system parameters such as deposition time, gas pressure, susceptor temperature, methane concentration, distance between the cathode and the substrate, substrate material, and surface treatment indicates that diamond deposition in such a reaction is a composite process. By varying the susceptor temperature and gas pressure during deposition, the deposition process can be tailored in favor of the synthesis of structurally uniform diamond thin films. The deposits, obtained at a growth rate of about 1 μm/h, have been characterized using scanning electron microscopy, Raman spectroscopy, Auger spectroscopy, x-ray diffraction, reflection high-energy electron diffraction, infrared absorption spectroscopy, and current-voltage curve plotting.