Growth of nitrogen doped diamond using inductively coupled thermal plasma CVD.

摘要

The synthesis of doped diamond films for electrochemical applications has raised an interest in developing novel techniques that could permit the production of large surface electrodes. A Thermal RF-ICP torch provides accurate nitrogen incorporation into the plasma phase without the addition of undesired contaminants. The diamond film is deposited on a molybdenum substrate at higher growth rates than other plasma CVD processes (low pressure plasmas). A detailed study on bias enhanced TP-CVD of diamond identified the optimum substrate temperature (1000°C) and improvement in the deposition qualities by applying a biasing potential. A negative potential is applied for increased nucleation and a positive potential is applied for a higher film growth and diamond quality. The gasses required are namely argon, hydrogen, methane, and nitrogen. The surfaces were analyzed using techniques such as SEM, Raman spectroscopy, CHN, atomic force microscope, and kelvin probe force microscopy. Nitrogen doped diamond deposition using low pressure plasma such as microwave plasma enhanced deposition determined that nitrogen decreases the quality of diamond and enhances graphite formation. Similarly nitrogen incorporation in thermal plasma CVD showed in the present work to reduce the nucleation density. Advantages such as a high growth rate (100mum/hr) and the diamond quality were not affected. The doping efficiency of 7x10 -3 for the TP-CVD process of this study indicates a higher incorporation of nitrogen into diamond when compared to cold plasma processes.