SYSTEMATIC STUDY OF DIAMOND FILM DEPOSITION IN AN ATMOSPHERIC-PRESSURE STAGNATION-FLOW FLAME REACTOR

An experimental study of diamond-film deposition is reported that util ized a scaled-up, stagnation-flow flame reactor. Films were deposited using highly strained premixed acetylene-oxygen-hydrogen flames. The r oles of flame stoichiometry, deposition temperature, and the use of ni trogen and argon diluents are evaluated. The experimental growth resul ts are analyzed based on the participation of methyl and hydrogen radi cals in the diamond growth process. The deposition results, both growt h rates and film quality based on Raman and SEM analysis, correlated w ell with recent calculations of the predicted methyl radical to atomic hydrogen ratios. Flame temperature was found to have a pronounced eff ect on diamond deposition that is likely coupled to the delivery of me thyl radicals and hydrogen atoms to the substrate surface. Overall, th e atmospheric-pressure reactor performed well. demonstrating successfu l scale-up, but flame stability and other engineering controls were ne cessary for achieving uniform diamond deposition and high growth rates . (C) 1998 Elsevier Science S.A.