Quantitative analysis of carbon distribution in steel used for thermochemical polishing of diamond films

Cylindrical steel plates used for the thermochemical polishing of chemical vapor deposited (CVD) diamond films at elevated temperatures are investigat ed regarding their carbon content using X-ray and ion beam analysis. The su rface distribution of carbon is investigated at randomly selected areas on two plates, one virgin and another on which a CVD diamond film is polished for 1 h at 950 degreesC. The investigation is carried out with a scanning e lectron microscope (SEM) operated at an energy of 5 keV. Analysis of the SE M energy dispersive X-ray analysis spectra manifest inhomogeneity in the su rface distribution of carbon on both steel samples. Moreover, the absolute concentration of carbon on the steel plate on which diamond is polished for 1 h almost triples that of the virgin sample. Elastic recoil detection ana lysis (ERDA) depth profiling is performed on several steel plates used to p olish as-grown CVD diamond films for periods between 0.5 and 8 h at 950 deg reesC. ERDA carbon profiles show inhomogeneity for three samples on which p olishing is successively done for 8 h. Raman spectra of post-polished steel plates reveal graphite bands and C-H-n complexes at exactly the wavenumber s they appear on the diamond samples. This is a clear manifestation that th e steel surfaces do not necessarily contain only atomic carbon after thermo chemical polishing. (C) 2001 The Electrochemical Society.