Lattice location of erbium atoms implanted into silicon

Silicon implanted at a temperature of 350 degrees C with Er ions at energies of 0.55-2 MeV is studied by Rutherford backscattering and channeling spectroscopy, Angular scan profiles through the [110] and [100] channels taken in the (100) plane were measured. The angular scan profiles of erbium, in particular flux peaking in the [110] channel, show that the Er atoms locate predominantly in the middle of the [110] channel, corresponding to the hexagonal interstitial positions. Monte Carlo simulations have been performed for the assumed hexagonal interstitial location of the implanted Er atoms, They well reproduce the experimental backscattering spectra and angular scan profiles. It has also been shown that annealing at 600 degrees C results in an increase of the hexagonal interstitial fraction, Additional short time annealing at 900 degrees C leads to precipitation of an Er-Si phase, which is reflected by the remarkable increase in the backscattering yield from the erbium doped layer.