Precipitation of Sn in metastable, pseudomorphic Si0.95Sn0.05 films grown by molecular beam epitaxy

Strained and relaxed Si0.95Sn0.05 films grown by molecular beam epitaxy wit h enriched Sn-119 on silicon and Si1-xGex substrates, respectively, have be en investigated by Sn-119 conversion electron Mossbauer spectroscopy. The S n concentration exceeds the maximum solid solubility of approximate to0.01% , however, the Sn atoms are found to be located on substitutional sites in the matrices. Upon annealing to temperatures greater than or equal to 800 K the formation of first alpha -Sn and then beta -Sn precipitates has been f ollowed. Pronouncedly, different precipitation effects found upon an ion im plantation of the samples are also briefly reported. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.