Research on Amorphous Silicon Thin-Film Structure and Growth Processes Using Nonlinear Dynamics Methods
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0910-A05-01
Research on Amorphous Silicon Thin-Film Structure and Growth Processes Using Nonlinear Dynamics Methods Nikolay Viktorovich Bodyagin, Sergey Pavlovich Vikhrov, Tatiana Gennadievna Larina, and Stanislav Mursalovich Mursalov Chare of Biomedical and Semiconductor Electronics, Ryazan State Radioengineering University, 59/1 Gagarina st., Ryazan, 390005, Russian Federation ABSTRACT There proved a possibility of applying the self-organization theory to the growth of noncrystalline thin-films and to the detection of ordering in their structure. Methods of analyzing the dynamics of complex systems are modified so as to investigate the structure of noncrystalline thin films. There offered new principles of the construction of material growth control systems. INTRODUCTION Properties of thin-film silicon structure strongly depend on parameters of technologies. Therefore mechanisms and dynamics of their fabrication are given serious attention. There exist basic ways of getting information about growth mechanisms, such as: – essential reactions occurring in plasma and on the film surface (necessary for silicon thinfilm grown from a gas phase by various methods). In this case constants of reaction speeds remain unknown. However, this approach as well as other methods of research on growth processes in situ is not provided with an effective theory of revealing growth dynamics. Specifically, it fails to explain the formation of various heterogeneities, the low degree of structure reproducibility etc.; – either hydrodynamic equations or simulative experiments (for the purpose of identifying mechanisms of the structural - chemical heterogeneity formation while investigating the growth of volumetric amorphous samples or crystals). Yet they are difficult to use in actual technologies because of the boundary conditions being excessively simplified. The direct experiments carried out to determine the dynamics of the melt-solid transition via dispersion technique concerned only water and salt by way of example [1]. Nevertheless, even they did not show any dynamic transition regularities since the tool of analysis was the autocorrelation function (ACF), which is useful only in studying linear systems. The surface structure of thin-film amorphous silicon, as a rule, is investigated with the help of various kinds of microscopy. The images obtained are processed either visually or by application of some analytical methods, such as fractal and multifractal parameterization, the Fourier-analysis, the wavelet-analysis. Through their use one can obtain characteristics of local elements of the structure or statistically averaged values of certain quantities. However, the data have a small generality and lack information value. Statistical methods can be more or less successfully applied to equilibrium states or approximating to those, which are nothing more than particular cases of evolution. This being so, their employment is not sufficient for the description of film complex structure. So existing techniques for investigating the gro
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