Equilibrium predictions of the role of organosilicon compounds in the chemical vapor deposition of silicon carbide.

摘要

Equilibrium calculations are reported for a range of conditions used to deposit silicon carbide (SiC) from Si-C-H mixtures such as those using SiH(sub 4), C(sub 2)H(sub 4), and H(sub 2) as reactants. Included are 37 molecules containing both silicon and carbon, allowing as assessment to be made of the importance of organosilicon species to the deposition process. The results indicate that Si(sub 2)C and SiCH(sub 2) may contribute to epitaxial SiC deposition and that formation of these and other organosilicon species is favored by low H(sub 2) concentrations. In addition, simulations of gas-phase equilibria expected under low-pressure, low-temperature conditions show that some organosilicon radicals that are kinetically favored are also thermodynamically favored. These include SiC(sub 2), SiCCH, and HSiCCH, which could results from the reactor of SiH(sub 2) with unsaturated reactants such as C(sub 2)H(sub 2). The results suggest that combining an inert carrier gas with an excess of a surface-reactive hydrocarbon such as C(sub 2)H(sub 2) could increase deposition rates without forming silicon-rich deposits. 25 refs.