The present invention is preparation process of three-layer diamond film in controllable thickness, belongs to the field of chemical vapor deposition technology of inorganic non-metal material, and aims at obtaining diameter film with proper roughness and thickness simultaneously. In an available chemical vapor deposition plant with hot filament and by means of regulating the carbon source concentration, depositing temperature, reaction pressure, applied bias and other parameters, three-layer diamond film is deposited on silicon chip. The present invention makes it possible to produce thick and flat diamond film without need of the post polishing treatment on the film. |