High-Temperature Kinetics of AlCl3 Decomposition in the Presence of Additives for Chemical Vapor Deposition

A numerical study has been performed modeling the gas-phase reactions occurring during the chemical vapor deposition ~CVD! of alumina from AlCl3 /CO2 /H2 mixtures. The purpose is to answer whether and to what extent trends in the decomposition of AlCl3 via gas-phase reactions can explain experimentally observed trends in CVD deposition of aluminum-containing films. The AlCl3 decomposition is predicted to occur via a free-radical chain mechanism that, in the presence of H2 , has H atoms and the AlCl2 radical as the primary chain carriers. We find that the present kinetic model predicts trends for the decomposition rate of AlCl3 in the gas phase that are consistent with trends observed experimentally for the Al2O3 deposition rate. Based on these results, the chemical kinetics model is used to study the effects on AlCl3 thermal decomposition of other additives ~H2O2 , H2O, O2 , Cl2! for which no experimental data are available in the literature. H2O2 is predicted to be a particularly efficient promoter for AlCl3 thermal decomposition. The mechanism also predicts that the presence of AlCl3 dramatically increases the rate of H2O production compared to H2O production from CO2 and H2 in the absence of AlCl3 . © 2002 The Electrochemical Society. @DOI: 10.1149/1.1467366# All rights reserved.