Abstract
Diamond was deposited on a large-area substrate (SiAlON: 100×30×5mm, deposition surface: 100×30mm) by hot-filament CVD with using a straight 140mm-long TaC filament under H2-3%CH4 at 25 Torr for 130min, and the morphology, quality and thickness of the film were examined by SEM and Raman spectroscopy. No tension was applied to the filament during heating up to 2600°C for diamond deposition and no visible deformation of the filament after deposition was observed. The deposited film showed the clear facet and Raman peak of diamond all over the deposition surface. Uniformity of film thickness is good in the longitudinal direction of the filament but poor in the transverse direction. Deposition rates were about 4μm/h at the center nearest the filament and about 1μm/h at the edge farthest from the filament.
