Ion beam mixing of silicon-tin multilayers

Silicon and tin multilayers of total thickness 200 nm have been deposited at room temperature on beryllium and glass plate substrates under high vacuum (<5. 10^?7 mbar). The average atomic tin fraction of the whole layer varied from 0.12 to 0.60. The samples were irradiated at room temperature with Xe⁺ ions of 900 keV energy with fluences of 1.10¹⁵ to 2.10¹⁶ ions. cm^?2. Rutherford backscattering spectrometry (RBS) was used to check overall composition before irradiation. After irradiation, a substitutional Sn site was evidenced by means of¹¹⁹Sn conversion electron Mössbauer spectroscopy (CEMS), the relative population of which depends on composition and irradiation fluence. Transmission electron microscopy (TEM) was used to monitor the evolution of the samples with irradiation fluence. Electrical measurements show semiconductor behaviour of the mixed multilayers with electrical resistivity ranging from 10² to 10^?3 Ω.cm as a function of composition.