チューブ型熱フィラメントCVDによるダイヤモンドの合成に及ぼすチューブ長の影響

抄録

For this study, we synthesized diamond using the hot tube chemical vapor deposition （CVD） method, for which the filament of thermal filament CVD is replaced by cylindrical metal foil. Effects of the tube length, total gas flow rate, and distance between the gas outlet and the substrate were investigated when using this method. Diamond and nanocrystalline diamond （NCD） films were obtained with tube lengths greater than 10 mm. Additionally, longer tube lengths were associated with increased deposition rates and decreased film quality, suggesting enhanced gas decomposition. The deposition rate increased along with the total flow rate. At 1500 ℃ tube temperature, the maximum deposition rate of 6 μm/h was achieved under conditions of 3 mm substrate distance and 20 mm tube length. The intensity ratio of the diamond peak to the non-diamond peak, calculated from the Raman spectrum, reached a maximum value of 3.2 for 10 mm tube length and 10 mm substrate distance.