Morphology variation of diamond with increasing pressure up to 400 torr during deposition using hot filament CVD

• Published in: Thin solid films 2001-11, Vol.398, p.175-179
• Main Authors: Kang, Min-Sik, Lee, Wook-Seong, Baik, Young-Joon
• Format: Article
• Language: English
• Subjects: Hot filament chemical vapor deposition; Nanocrystalline diamond; Pressure effect
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(01)01390-6

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.