2000 Volume 26 Issue 6 Pages 763-769
In this study, alumina thin films were prepared by chemical vapor deposition from aluminum chloride, hydrogen and carbon dioxide, and growth kinetics were investigated. The deposition experiments were carried out in a non-isothermal tubular CVD reactor. The deposition rate of alumina and temperatures at inner surface, and pressure near the inlet and exit of the reactor were measured. To clarify the growth kinetics, the numerical model, in which the axial distributions of temperature and pressure in the reactor were estimated from the measured values by the fourth-order and linear polynomial interpolation, respectively, has been developed. To confirm these estimations, the distributions of temperature and pressure were calculated using a two-dimensional numerical analysis. The measured and estimated distributions of the temperature and pressure agreed well with calculated results in He and H2 streams. In an Ar stream, the measured temperature did not agree with the calculated gas temperature near the inlet and outlet of the reactor where the temperature was drastically changed in the axial direction. Therefore, the deposition experiments were performed in a He stream. The oxidation of H22 by CO2, which is the rate-controlling step for alumina CVD, mainly occurrs in the gas-phase, and its activation energy is found to be 235kJ/mol.
