Homoepitaxial Growth Rate Studies on Diamond (110), (111), and (100) Surfaces in a Hot-Filament Reactor.

摘要

Growth rates of homoepitaxial (1 10), (I 1 1), and (100) diamond films were experimentally determined, for the first time, in a hot filament reactor using methane and carbon tetrachloride as the carbon source. Methane concentrations from 0.07% to 1.03% in H2 were studied at a subsum temperature of 970 'C. Growth ran were found to be crystal-face dependent with respect to methane concentration, being linear or first order for the (100) orientation, sublinear for (110), and sigmoidal for (1 1 1). The observed growth kinetics of (I 1 1) suggest the viability of an acetylene mechanism for (1 1 1), along with the methyl radical mechanism at methane concentrations above 0.73%. CC14 concentrations from 0.06% to 0.69% in H2 were also investigated at a substrate temperature of 970 C. Growth rate behavior was similar to that of methane for all three crystal faces. The temperature dependence of the growth rates was also crystal-orientation dependent. At subsum temperatures above 730 C, growth rates are thought to be mainly transport limited, yielding effective activation energies of 8+/-3, 18 + or - 2, and 12+ or - 4 kcal/mol for (100), (I 10), and (1 1 1) orientations, respectively. At substrate temperatures below 730 C, growth rates are thought to be surface reaction rate-limited, with an overall effective activation energy of 50 + or -19 kcal/mol for the three crystal-orientations studied.