Abstract
The effect of the growth pressure and substrate temperature on diamond crystallite size was investigated during deposition by hot filament chemical vapor deposition (CVD). A methane–hydrogen gas mixture was used as the precursor gas. The gas flow rates of methane and hydrogen and the deposition time were kept constant at 4 and 100 sccm and 10 h, respectively. The growth pressure and substrate temperature were varied between 40 and 400 torr and between 1020 and 1250°C, respectively. The structure of the films was characterized by high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and micro-Raman spectroscopy. Typically, the diamond crystallite size decreased with increasing pressure and decreasing substrate temperature. For example, with increasing growth pressure at 1100°C, the structure of the film gradually changed from microcrystalline to nanocrystalline diamond and the non-diamond defects increased. As the substrate temperature increased at 200 torr, the structure of the film gradually changed from nanocrystalline to microcrystalline diamond.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have