Atomic diffusion near to an aluminum grain boundary was analyzed in order to investigate a basic mechanism of stress-induced migration in a thin wiring line. Molecular dynamics based upon the effective-medium theory was applied to a model containing a surface and ∑=5[001] symmetrical tilt grain boundary with bamboo-like structure. Effective-medium theory was constructed using no empirical knowledge and was known to be effective for analysis of inhomogeneous atomic structure. Above the transition temperature from low- to high-temperature modes of stress-induced migration, jump motion of atoms near the grain boundary occurred and the diffusion coefficients which were estimated from the mean square displacement of atoms increased remarkably. The diffusion coefficients had the largest value in the region where the grain boundary intersects the surface. The magnitude of diffusion coefficients in the grain boundary region and its temperature dependence agreed well with the results obtained by Plimpton et al., who had used several pair-wise interatomic potentials. It was proved that the diffusion coefficients increased as an exponential function of the tensile strain.

Atomic Diffusion near Al-Grain Boundary (A Molecular Dynamics Analysis Based on Effective-Medium Theory). Kitagawa, H., Nakatani, A., Ogata, S., Saitoh, K., Maegawa, Y.: Transactions of the Japan Society of Mechanical Engineers A, 1996, 62[602], 2358-63. See also: JSME International Journal A, 1997, 40[3], 203-10