Influence of the carrier gas in the growth kinetics of TiO$_{2}$ films deposited by aerosol assisted chemical vapor deposition with titanium-diisopropoxide as precursor

Abstract

Titanium dioxide thin films were deposited on crystalline silicon (100) substrates by delivering a liquid aerosol of titanium-diisopropoxide and by using oxygen and nitrogen as carrier gases. The crystalline and morphological features indicate that the films are deposited by a metal organic chemical vapor deposition process. This is strongly supported by the behavior of the growth rate r$_{g}$ as a function of the deposition temperature, which indicates that the film formation is limited by both, the diffusion in gas phase of the precursor species to the surface substrate and reaction of those species at that surface. Even though the r$_{g}$ line shape does not depend on the kind of carrier gas used to transport the aerosol, its absolute value and the activation energy E$_{A}$ that characterizes the surface reaction do. A fitting procedure to an equation that takes into account both limiting mechanisms (gas phase diffusion and surface reaction) yields: E$_{A} \cong $26.4 kJ/mol or E$_{A}$=21.4~kJ/mol when oxygen or nitrogen is employed as carrier gas, respectively.