Low temperature diamond film fabrication using magneto-active plasma CVD

Abstract 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,CH 3 OH/(H 2 +He), obtained by adding a helium to a usually-used gas mixtureCH 3 OH/H 2 , has been employed in this study. For a constant CH 3 OH concentration (30%), microcrystalline diamond films of good quality can be obtained at a ratio ofHe/(H 2 +He) up to 50%, and the growth rate increases with an increase in the ratio. WhenHe/(H 2 +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).