Origin of growth defects in CVD diamond epitaxial films

• Published in: Diamond and related materials 2008, Vol.17 (1), p.60-65
• Main Authors: Tallaire, A., Kasu, M., Ueda, K., Makimoto, T.
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects; Defects and impurities: doping, implantation, distribution, concentration, etc; Etching; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Homoepitaxy; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Specific materials; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of film growth; Thin film structure and morphology
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2007.10.003

Three types of growth defects commonly found epitaxial diamond films grown by chemical vapour deposition (CVD), namely unepitaxial crystals (UCs), hillocks with flat top (FHs) and pyramidal hillocks (PHs), were etched using hydrogen/oxygen plasma to discuss their origin. UCs formed at random locations on the grown layer without any apparent relation with the substrate. Their nucleation might be due to contaminants and their development controlled by the growth conditions in the plasma. In contrast, dislocations formed from impurities segregated at the interface between the substrate and the CVD layer, were found to be the origin of the FHs and the PHs. A simple crystal model that involves micro-faceting or twinning at an intrinsic stacking fault originating from the dislocation core is proposed to explain the formation and the evolution of the growth defects.