Construction of a new C-H-O ternary diagram for diamond deposition from the vapor phase

摘要

A new C-H-O ternarydiagram is presented based on radical species composition showing the regions for diamond deposition,non-diamond deposition,and no deposition from the vapor phase. This construction is based on the steady-state computations of gas-phase and gas-surface chemistry from the data points presented in the C-H-O ternary diagram based on feed gas compositon by Bachmann et al. (P.K.Bachmann,D.Leers, H.Lydtin. Diamond Relat.Mater.1(1991)1). The analysis of the computational results indicates that the radical species compositon does distinguish the three regions and helps explain the contradicting experimental data ponts using non-typical gas mixtures. The analysis also shows that the revised diagram based on radical species composition works only when carbon monoxide (CO) is treated as a non-participating species. The effects of temperature, pressure and flow rates on this new ternary diagram are also detailed.