THERMAL-DIFFUSIVITY OF DIAMOND FILMS SYNTHESIZED FROM METHANE BY ARC-DISCHARGE PLASMA-JET CVD

Diamond films 10-36 mum thick were synthesized via d.c. plasma jet chemical vapour deposition. The films were separated from their silicon substrates by dissolving the silicon in aqueous HF. Examinations of the free-standing diamond films by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy have shown that the quality of the films is close to that of natural diamond. The thermal diffusivities of the films were measured at room temperature by the thermal wave mirage technique. This method allows local measurements representative of an area of about 1 mm2. The measured values (1.6-2.5 cm2 s-1) were higher than those of copper (1.25 cm2 s-1) and silicon (0.86 cm2 s-1).