Numerical analysis method for growth kinetics of chemical vapor depositionof alumina using a non-isothermal CVD reactor

In this study, alumina thin films were prepared by chemical vapor depositio n from aluminum chloride, hydrogen and carbon dioxide, and growth kinetics were investigated. Thr deposition experiments were carried out in a non-iso thermal tubular CVD reactor. The deposition rate of alumina and temperature s at inner surface, and pressure near the inlet and exit of the reactor wer e measured. To clarify the growth kinetics, the numerical model, in which t he axial distributions of temperature and pressure in the reactor were esti mated from the measured values by the fourth order and linear polynomial in terpolation, 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 o f the temperature and pressure agreed well with calculated results in He an d H-2 streams. In an Ar stream, the measured temperature did not agree with the calculated gas temperature near the inlet and outlet of the reactor wh ere the temperature was drastically changed in the axial direction. Therefo re, the deposition experiments were performed in a He stream. The oxidation of H-2 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 235 kJ/m ol.