Detailed in-situ monitoring of film growth: application to TiSi₂ chemical vapor deposition

An experimental approach for monitoring chemical vapor deposition is described that combines in-situ, real-time monitoring of deposition rate and gas composition together with transfer capabilities into ultrahigh vacuum for Auger analysis. This approach has been applied in the specific case of TiSi₂ low-pressure deposition on Si using TiCl₄ and SiH₄. In the early stages of growth, Si for the growing film is supplied directly from the substrate. In later stages, Si arrives through SiH₄ adsorption. The primary gas phase reaction products are H₂, HCl, SiH₃Cl and the radical species SiCl₂. Removing surface contamination from the substrate is not sufficient to promote film nucleation; surface defects are apparently required as well. Steady-state multiplicity in the reaction rate is observed near 700°C for large SiH₄:TiCl₄ ratios.