The Mass Spectrometric Investigation of the Chemical Vapor Deposition Process for Alumina.
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MASS
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Mass spectrometric analysis has been made of the chemical vapor deposition process for alumina from gaseous reagents of Cl2H2 over aluminum metal and H2OO2 or oxygen. The experiments were performed in a specially designed concentric furnace followed by a high pressure sampling technique and mass spectrometric detection. From the analysis of Al2O3 deposits, it is found that opaque to transparent polycrystalline alumina can be prepared by a proper combination of gaseous reagents at selected temperatures. The optimum operating conditions and appropriate gaseous mixtures are described and recommended. Mass spectra reveal that the major aluminum chloride specie at deposition temperatures above 1000 C is AlCl, contrary to earlier literature. The formation of solid Al2O3 in the present CVD process is a surface nucleation phenomena and no vapor phase homogeneous nucleation occurs. The overall reaction is believed to be principally 2AlClg H2Og O2g Al2O3s 2HClg and, to a lesser extent, 2AlClg 3H2Og Al2O3s 2HClg 2H2g. Author
- Manufacturing and Industrial Engineering and Control of Production Systems
- Atomic and Molecular Physics and Spectroscopy