Using magneto-active plasma CVD, diamond films have been fabricated at 0.01 torr with a substrate temperature of about 400°C. From the viewpoint of increasing plasma density, a gas mixture, CH3OH (H2 + He), obtained by adding a helium to a usually-used gas mixture CH3OH H2, has been employed in this study. For a constant CH3OH concentration (30%), microcrystalline diamond films of good quality can be obtained at a ratio of He (H2 + He) up to 50%, and the growth rate increases with an increase in the ratio. When He (H2 + He) is higher than 50%, graphite appears in the film because of the heavy bombardment on the diamond surface by the accelerated helium species in the plasma at low pressure (0.01 torr).
ASJC Scopus subject areas
- 化学 (全般)