Chemical Liquid Deposition Preparation Of Alumina Films

Inorganic oxide films are widely used in modern microelectronics, solid-state electronics, optical engineering. The fabrication of thin oxide films has become a hot spot of research in physics of condensed matter. Traditional methods of manufacturing oxide films include thermal oxidation, chemical vapor phase deposition, metal-organic chemical vapor phase deposition, sol-gel method and so on. However, most of this process require very complex equipment and are not easy to maneuver. A new way of oxide coating--chemical liquid phase deposition (CLD) was first pioneered by Nagayama et al. in 1988. It can make thin oxide films under much simpler experimental conditions and therefore has attracted a lot of interest. However, CLD-Al2O3 films have not been studied all over the world. In this paper, a new method of manufacturing Al2O3 films by CLD is reported. The process of CLD-SiO2 films is first studied in detail following Houng et al.'s work. After that, CLD of Al2O3 is carried out through a system equipped with a Teflon vessel immersed in a water bath. The chemicals used to make growth solution include Al2(SO4)3.18H2O, NaHCO3 and deionized H2O. That is a hydrolysis procedure of inorganic salts followed by high-temperature annealing process. The quality of the films is examined by AFM, AES, EDS, XRD, FTIR, etc. The experimental results strongly suggest that as-deposited Al2O3 films are fairly uniform and flat, chemically pure (no hydrogen element existing) and belong to high-hardness-value crystalline super-thin films.