Conditioning of the filament for diamond deposition by hot-filament chemical vapour deposition method

Abstract

A tungsten filament, 0.12 mm in diameter, was conditioned by heating in a mixture of methane and hydrogen of three different concentration ratios. The filament was heated by an electric current. The procedure was carried out stepwise keeping either the voltage or the temperature of the filament constant. Changes in the filament material were monitored by resistance and temperature measurements. The chemical composition was checked using X-ray diffraction (XRD) analysis. The final state of the filament was investigated and photographed using the scanning-electron microscopy (SEM) technique.