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We report high resolution (<0.05 cm−1) photoluminescence (PL) spectra of erbium implanted float-zone (FZ) and Czochralski grown (CZ) silicon. We show that the PL spectrum of cubic Er centers observed in CZ-Si annealed at 900°C is the dominant emission in FZ-Si for the same annealing conditions. We assign it to isolated, interstitial erbium. We observe also two other kinds of optically active Er centers with lower than cubic site symmetry: (i) O-related (found only in CZ Si) and (ii) those related to radiation defects. We conclude that coimplantation with light elements does not lead to the formation of Er-codopant complexes, but rather to Er forming complexes with implantation induced lattice defects.

Channeling implantations of 20 keV boron into silicon have been performed with doses between 1013 and 1016 cm−2 in the [100], [110], and [211] direction, and parallel to a (111) plane. Simulations using an empirical electronic stopping model agree very well with the experimental results. The model has been obtained considering a large number of random and channeling implantations published in the literature. It contains a nonlocal and an impact parameter dependent part with the nonlocal fraction increasing with energy. Moreover, a computationally efficient damage accumulation model is presented which takes point defect recombination into account. It is found that due to interactions within a recoil cascade only 1/8 of the generated damage is stable, and that damage saturation takes place at a concentration of 4×1021 cm−3. Comparison of simulations and experiments indicates that displaced atoms reside on random positions rather than on tetrahedral interstitial sites in the silicon lattice.