Control of abnormal grain inclusions in the nanocrystalline diamond film deposited by hot filament CVD

• Published in: Diamond and related materials Vol. 18; no. 11; pp. 1369 - 1374
• Main Authors: Li, H., Lee, Hak-Joo, Park, Jong-Keuk, Baik, Young-Joon, Hwang, Gyu Weon, Jeong, Jeung-hyun, Lee, Wook-Seong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2009; Elsevier
• Subjects: Bias growth; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Hot filament CVD; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanocrystalline diamond film; Physics; Specific materials; Theory and models of film growth; Bias growth; Nanocrystalline diamond film; Hot filament CVD; Hot filament chemical vapor deposition; Methane; Aluminium oxide; Synthetic diamond; Thermocouples; Growth mechanism; Alumina
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2009.08.009

Formation of abnormal grain inclusions in nanocrystalline diamond films deposited by hot filament CVD (HFCVD) was investigated. The phenomenon was attributed to two different origins: an intrinsic and an extrinsic one. The inclusions due to the intrinsic origin could be either avoided or weakened by controlling chamber pressure, CH 4/N 2 concentrations in H 2, and by positive substrate bias. The extrinsic origin for the abnormal grains was found to be the contamination from the alumina insulation tubes for the thermocouple placed near the substrate, which were degraded by the extended exposure to the high temperature and strongly reducing atmosphere.