Low-pressure, low-temperature, and remote-plasma deposition of diamond thin films from water-methanol mixtures

We have deposited diamond thin films remote from the active plasma region using an electron cyclotron resonance chemical vapor deposition technique. Diamond films were fabricated at temperatures in the range of 550-650°C and gas pressures between 25 and 60 mTorr. The volume ratio of water to methanol was varied from 1:20 to 1:5 to optimize diamond film growth. High methanol content resulted in multiple nucleation in the growing diamond film, while higher water content led to complete etching of the film. A positive electrical bias was found to be essential for diamond thin film growth remote from the plasma region. The films were characterized by x-ray diffraction, micro-Raman, and scanning electron microscopy for phase identification, surface morphology, and bonding characteristics.