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 sta ges form the main focus. The temperatures and pressures chosen yield n early zero net consumption in some cases. Real-time rate measurements of growth, substrate consumption, and product desorption provide an un precedented view of the governing processes. At the outset, Cl poisoni ng of the Si substrate controls nucleation. Crystallites nucleate in t he C49 structure with significant attendant substrate consumption. Con sumption decreases rapidly as the crystallites grow, because adsorbed Si provided by surface diffusion no longer poisons SiH4 adsorption. Th e 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, attend ed by a decrease in growth rate and a stoppage of Si grain formation. This work details the effects of temperature, source gas pressures, an d substrate doping on all these processes, together with issues of rat e multiplicity and stability.