GAS-FLOW EFFECTS IN SYNTHESIS OF DIAMOND BY HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION

Hot-filament chemical vapor deposition was employed to study the effec t of gas flow dynamics on diamond growth. The density and growth rate of diamond within the patterned region of copper and silicon substrate s was found to be twice as large as compared with that on a flat (unpa tterned) surface. The density of diamond nucleation increased on patte rned silicon and copper substrates with an increase in the methane con centration from 1.0% to 1.5% in the gas mixture of methane and hydroge n (CH4 + H-2). Selective growth of diamond was achieved without using diamond seed or paste, or scratching the patterned silicon substrate. About 90% diamond coverage and a continuous diamond film (75 mum) were achieved on the square-patterned silicon and copper substrates, respe ctively, at a methane concentration of 1.5%. The growth of diamond wit hin the wells was discussed on the basis of gas flow dynamics. The pre sent analysis is consistent with available theoretical models.