Characterization of lattice damage in ion implanted silicon: a Monte Carlo simulation combined with double crystal X-ray diffraction

Double crystal X-ray diffractometry is applied to the characterization of damage in silicon samples, irradiated with 60 keV self-ions for doses ranging from 5 x 1012 cm-2 to the threshold for amorphisation. The samples were also electron beam annealed in such a condition as to give rise to a temperature of 800 0C. The in-depth strain and atomic disorder distributions, due to the implantation defects, were determined for the specimens before and after high temperature annealing. This was possible by application of the dynamical theory of X-ray diffraction from imperfect crystals and by taking into account the diffuse (thermal, Compton) scattering accompanying Bragg diffraction intensity measurements. Transmission electron microscopy observations, in conventional (planar) and cross-section mode, were also performed. The results of these analyses were compared with a complex simulation method, designed to account for the physical origin of the disorder. The method consists of a Monte Carlo simulation of the damage growth during implantation and of the defect annealing and clustering in a warm lattice. The evolution of disorder is examined either in the phase of spontaneous annealing subsequent to the implantation or during the externally induced annealing. Theory and experiments led to a close characterization of damage in terms of cluster size, type and concentration, both before and after annealing. (author)