A method has been developed to determine the dislocation configuration from the breadth and shape of diffraction lines at different specimen tilt angles and/or different diffraction angles. The method uses the notion "set of dislocations" [1], being a number of straight parallel dislocations on one slip system and which show a restricted random distribution [2]. By that an analytical expression could be derived for the integral breadth caused by the microstrain from all possible sets of pure edge and/or pure screw dislocations [3]. The expression is a summation of terms. Each term depends on the diffraction vector and on the Burgers vector, the dislocation line vector and the (unknown) density of one dislocation set.
The method was applied to polycrystalline aluminium layers, deposited onto a silicon <100> single-crystal wafers. The layers exhibited a strong [111] fibre texture with the fibre axis perpendicular to the substrate. Analysis of the X-ray diffraction measurements showed that the dislocations present are predominantly screw dislocations. The densities of dislocation sets with Burgers vectors parallel to the plane of the layer is very much lower than the densities of dislocation sets with inclined Burgers vectors.
1. M. Wilkens, Phys. Stat. Sol. (a), vol.2, (1970), 359-370
2. M. Wilkens, Acta Metall., vol.17, (1969), 1153-1159 (in
German)
3. M.A. Krivoglaz & K.P. Ryaboshapka, Phys. Met. Metallogr., vol.15,
(1963), 14-26