A predictive kinetic model for the chemical vapor deposition of TiSi₂

A predictive kinetic model has been constructed to describe the chemical vapor deposition of titanium disilicide from TiCl₄ and SiH₄. This model relies on mass balances for all atomic species and uses inputs of temperature and source gas pressures to yield outputs of deposition rate, desorption rates, and film stoichiometry. Crucial to model construction were over 25 numerical kinetic parameters (none adjustable) for reaction steps that we have measured previously in ultrahigh vacuum. The model predictions have been compared with new deposition experiments capable of monitoring all the outputs in situ. In virtually every respect, quantitative agreement exists between the model and experiment, including the existence and general behavior of rate multiplicity. In a practical view, the model indicates that many problems currently plaguing TiSi₂ chemical vapor deposition disappear if the pressure of TiCl₄ is reduced. In a broader view, this work represents to our knowledge the first time an ultrahigh vacuum-based kinetic model has successfully guided the a priori development of a process governed by surface reactions in which optimization has not already been accomplished by enlightened trial and error.