Dynamics of Nanostructure Formation During Thin Film Deposition
Coverage evolution, during atomic deposition on a substrate may be described, on mesoscopic scales, by dynamical models of the reaction-diffusion type, which combine reaction terms representing chemical processes such as adsorption-desorption and nonlinear diffusion terms. Below a critical temperature, uniform deposited layers are unstable, which leads to the formation of nanostructures corresponding to regular spatial variations of substrate coverage. For increasing mean coverage close to one-half, the dynamics is of the Cahn-Hilliard type, and one should observe a succession of structures going from hexagonal arrays of high coverage dots, to stripes and finally to hexagonal arrays of low coverage dots. For mean coverage close to one, the nanostructures are highly nonlinear, and have to be obtained numerically. Structures obtained in the case of Al layers deposited on TiN substrates are presented. Comparisons between weakly and highly nonlinear structures are performed.
Key wordsthin film deposition nanostructure reaction-diffusion dynamics instability
Unable to display preview. Download preview PDF.
- Suo, Z. and Lu, W., “Self-organizing nanophases on a solid surface”, in Multiscale Deformation and Fracture in Materials and Structures, The James R. Rice 60th Anniversary volume, edited by T.J. Chuang and J.W. Rudnicki, Kluwer Academic Publishers, Dordrecht, 107–122 (2000)Google Scholar
- Ghoniem, N. M., Heinisch, H., Huang, H., Yip, S. and Yu, J., eds., Journal of Computer Aided Materials Design, Special Issue for Multiscale Materials Modeling Symposium of the 5th IUMRS, Kluwer, Dordrecht (1999).Google Scholar
- Walgraef, D., “Reaction-Diffusion approach to nanostructure formation during thin film deposition“, to appear, Phil. Mag. A.Google Scholar
- Walgraef, D., “Spatio-Temporal Pattern Formation (with examples in physics, chemistry and materials science”, Springer Verlag, New York, 1996.Google Scholar
- Walgraef, D. and Clerc, M.G., to appear.Google Scholar