Erbium surface segregation is observed during growth of Er-doped Si by molecular beam epitaxy on Si(100) at 600 °C. Once a critical Er surface areal density of 2 X 1014 Er/cm2 is reached, enhanced Er trapping is observed, possibly due to the formation of silicide precipitates. Er segregation on Si(100) is fully avoided when growth is performed in an oxygen background pressure of ~10-10 mbar, due to the formation of Er-O complexes. No Er segregation is observed on Si(111), which is attributed to the formation of epitaxial Er3Si5 precipitates.

Appl. Phys. Lett.
Photonic Materials

Serna, R., Lohmeier, M., Zagwijn, P. M., Vlieg, E., & Polman, A. (1995). Segregation and trapping of erbium during silicon molecular beam epitaxy. Appl. Phys. Lett., 66, 1385–1387.