On the post-etching of diamond thin films in a hydrogen-oxygen atmosphere

• Published in: Journal of materials science letters 1993, Vol.12 (9), p.687-689
• Main Authors: PENG XILING, XIAOLIN, C
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Mechanical and acoustical properties; adhesion; Physics; Solid surfaces and solid-solid interfaces; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0261-8028; 1573-4811
• DOI: 10.1007/BF00465593

In order to understand better the etching function of O2 during diamond synthesis, post-etching of diamond thin films was carried out under the same conditions as those used for diamond deposition. Films for post-etching were prepared at 1.4 vol% CH4 /H2 concentration for 23 h on Si(100) substrates using hot-filament assisted CVD, and had a thickness of 20 micron. Post-etching parameters are given. The post-etched films were then examined by SEM, XRD and Raman spectroscopy. It was found that etching of non-diamond and diamond carbon was enhanced by O2 in an H2-O2 atmosphere. This was largely attributed to newly formed more effective carbon etchants such as atomic oxygen and OH radical through various reactions, as well as through decomposition of water to OH + H. Molecular oxygen may also be dissociated to atomic oxygen under the filament activation. Atomic oxygen and OH radical have a much stronger etching effect on both non-diamond and diamond carbon, and control of O2 concentration is therefore important during diamond film synthesis. 8 refs.