Study On The Preparation And Growth Mechanism Of Nanocrystalline Diamond Films By Hot Filament Chemical Vapor Deposition Method

Nanocrystalline diamond films not only have the performance close to or the same as conventional micro-crystalline diamond films, but also have the advantages such as small grain size, smooth surface, small friction coefficient, a better field emission performance and ease of polishing, which can make up for the deficiencies of micro-crystalline diamond films and expand applications of diamond films. At present, the growth rate and growth quality of nanocrystalline diamond films still need to be improved, so it is very important to study the preparation of nanocrystalline diamond films with high growth rate and high growth quality.In order to prepare nanocrystalline diamond films, we mainly studied the growth technologies by hot filament chemical vapor deposition method in hydrogen/acetone gas mixtures and in argon/hydrogen/acetone gas mixtures. In order to study the growth mechanism of diamond films, optical emission spectroscopy was used in the diamond films deposition by hot filament chemical vapor deposition technique.In hydrogen/acetone gas mixtures, we mainly studied the influence of carbon source concentration and substrate temperature on the growth of nanocrystalline diamond films. In argon/hydrogen/acetone gas mixtures, we mainly studied the influence of argon concentration, reaction pressure, carbon source concentration and substrate temperature on the growth of nanocrystalline diamond films. In argon/hydrogen/acetone gas mixtures, growth rate and growth quality of diamond films are higher than that of hydrogen/acetone gas mixtures. Because the introduced argon can effectively improve plasma concentration in the system, thus can be beneficial to increase secondary nucleation rate, reduce the grain size and increase the growth rate.In addition, optical emission spectroscopy was used in the diamond films deposition by hot filament chemical vapor deposition technique. The concentration of C2 and CH in argon/hydrogen/acetone system is higher than that of argon/hydrogen/methane system. It appears oxygen containing groups favorable to etch graphite phase. Argon gains higher excitation energy with a shorter wavelength. Under the reaction pressure of 3.5 kPa CH group achieves maximum concentration.