Chemical bath deposition is a thin film technique in which semiconductor thin films of typically 0.02-1 mu m thickness are deposited on substrates immersed in dilute baths containing metal ions and a source of sulfide or seleide ions. Many I-VI, II-VI, IV-VI, and V-VI semiconductors are included in the list of materials deposited by this technique, II-VI compounds CdS, CdSe, ZnS and ZnSe being the most investigated. However, a matheratical model describing the growth mechanism of these films still remains to be established. The deposition process consists of a nucleation phase, growth phase, and a terminal phase, each of which depends on the concentration of the ions in the deposition bath, its temperature, dissociation constants of the metal complex ions, etc. In this paper w e propose a mathematical model, which can qualitatively account for most of the features of the experimentalo gowth curves of chemically deposited semiconductor films.
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