Diamond film deposition by downstream d.c. glow discharge plasma chemical vapour deposition

Abstract

A new d.c. glow discharge chemical vapour deposition (CVD) method was developed for diamond film (DF) deposition onto insulator substrates. This method uses ordinary d.c. plasma CVD equipment, but the anode system was modified both to insulate the substrate holder from the anode and to set the substrate downstream of the plasma. This is achieved by two methods. First, the anode was made from the tungsten grid and the insulated substrate was placed under the grid and out of the discharge area. Second, the anode was made from the thick-wall molibden tube and the substrates were placed on the insulator inside the tube. The experiments were carried out under a hydrogen pressure of 50–150 Torr and methane concentration of 1%–2%. The substrates (Mo or Si) were set on the silica substrate holder. The temperature was approximately 1000 °C. Diamond films were grown by both methods. Scanning electron microscopy, cathodoluminescence microscopy and spectroscopy, Raman scattering and X-ray diffractometry were used to study and compare the diamond films.