Thermochemical polishing of CVD diamond films

Abstract A new set-up for thermochemical polishing of CVD diamond films on a hot vibrating steel plate has been developed. The capability of the instrument and the polishing process have been investigated on free-standing polycrystalline CVD diamond films by flat polishing of large area samples (10×10 mm 2 ) and by bevelling polishing of low-angle (34°) diamond blades. The polishing rate has been found to be somewhat dependent on the crystal orientation, which resulted in a light patterning corresponding to the polycrystalline structure of the polished surfaces. A roughness of 6 nm has been achieved on the polished surfaces. The sharpness of the CVD diamond blades was less than 100 nm. The process of the thermochemical polishing can be described as a conversion of diamond into non-diamond carbon by the hot metal with a subsequent solution of this carbon in the metal.