Diamond synthesis with a superconducting magnet assisted hollow cathode plasma CVD apparatus

A magnetic field has a variety of influence on plasma and so can be applied to plasma chemical vapor deposition (CVD) to control the state of the plasma. However, the magnetic fields utilized for conventional plasma CVD are limited to less than approximately 0.2 T. In this study, superconducting magnet assisted hollow cathode plasma CVD apparatus has been developed to investigate the influence of stronger magnetic fields of up to 1.0 T on the film preparation using plasma. The characteristics of DC discharge were examined under magnetic fields of up to 1.0 T, and synthesis of carbon films was carried out with methane and hydrogen gases. The results obtained are as follows: the substrate temperature rises with increasing magnetic flux density applied to the plasma; diamond has been synthesized at a methane concentration of 1.5% when the magnetic field of 1.0 T is applied to a plasma at a substrate temperature of 650 degrees C and pressure of 2.67 kPa, while no deposits have been obtained without a magnetic field. (C) 1998 Elsevier Science S.A.