ABSTRACT
The modern CVD processes for growing diamond films are dependent on using hydrogen atom as catalyst. In the 1980s, Japanese invented several CVD processes that may grow metastable diamond at high deposition rates. As both the growth rate and the quality of diamond film are dependent on the concentration of hydrogen atoms; hence, all CVD processes for growing diamond are designed to enhance the dissociation of hydrogen molecules in the gas mixture to form hydrogen atoms. The hot filament CVD process may produce large diamond films with uniform thickness. The amount of diamond formed per unit time for all established CVD processes is directly proportional to the energy consumption rate. The intrinsic limitation of metastable CVD diamond growth has ruled out diamond films as a low cost source of diamond. Although the cause of CVD diamond growth by laser ablation is not fully understood, it is related to the chain reaction of laser bombardments.
