Rod-like defects with a {111} habit plane were identified, by means of electron microscopy, at a well-defined depth below the surface of specimens which had been subjected to implantation with 1MeV Si ions, to a dose of 1014/cm2, followed by annealing (900C, 10s). These coexisted with defects on {311} habit planes. Energy minimization calculations, using the Stillinger-Weber potential, were carried out for a self-interstitial atomic configuration. The final relaxed atomic configuration consisted of 5- and 8-membered rings. Calculated images which were based upon this atomic model matched so-called double-spacing experimental high-resolution electron microscopic images. The energy minimization calculations suggested the existence of a displacement vector of a<111>/10, perpendicular to the habit plane, in the case of the {111} defect. Diffraction contrast experiments revealed that, in the present specimens, about 10% of the rod-like defects had this displacement vector. The {111} defects were also observed by using a 120keV electron microscope. This was below the critical energy of 170keV which was required in order to generate Frenkel pairs in Si by means of electron irradiation. This indicated that the {111} defects could be generated by means of ion implantation and annealing.

C.T.Chou, D.J.H.Cockayne, J.Zou, P.Kringhøj, C.Jagadish: Physical Review B, 1995, 52[24], 17223-30