Nanometric powder of stoichiometric silicon carbide produced in square-wave modulated RF glow discharges

SiC nanometric powder has been obtained in square-wave modulated radiofrequency glow discharges from CH₄ and SiH₄ gas mixtures. Chemical and structural characterization revealed that the as-deposited SiC:H powder underwent spontaneous oxidation when exposed to atmosphere. To stabilise the powder chemically, we carried out a thermal treatment under vacuum (10 ⁴ Pa) consisting of heating to 800°C (20°C/min). The effects on the structure of the powder were examined by FTIR, EA, XPS and from optical transmittance measurements. They can be summarized as follows: dehydrogenation of the powder that induces the formation of a SiC carbidic network and chemical stability under atmospheric conditions, further confirmed by exposure to air for more than 6 months. In addition, TEM images showed that the annealed powder presented a short-range order in β-SiC units, but there was no evidence of size changes due to sinterization or compactaction phenomena. © 1998 Elsevier Science Ltd. All rights reserved.