Kinetics of TiSi2 formation and silicon consumption during chemical vapor deposition

This work examines the kinetics of titanium disilicide growth on (100) Si from TiCl4 and SiH4 by chemical vapor deposition. Early growth stages form the main focus. The temperatures and pressures chosen yield nearly zero net consumption in some cases. Real-time rate measurements of growth, substrate consumption, and product desorption provide an unprecedented view of the governing processes. At the outset, Cl poisoning of the Si substrate controls nucleation. Crystallites nucleate in the C49 structure with significant attendant substrate consumption. Consumption decreases rapidly as the crystallites grow, because adsorbed Si provided by surface diffusion no longer poisons SiH4 adsorption. The growth rate increases together with exposed silicide area, reaching a peak as the crystallites coalesce. Intercalated Si grains may appear. Coalescence provokes a rapid transformation to the C54 phase, attended by a decrease in growth rate and a stoppage of Si grain formation. This work details the effects of temperature, source gas pressures, and substrate doping on all these processes, together with issues of rate multiplicity and stability.