Segregation and trapping of Er during solid-phase crystallization of amorphous Si on crystalline Si is studied in a concentration range of 1016-5x1020 Er/cm3. Amorphous surface layers are prepared on Si(100) by 250 keV Er ion implantation, recrystallized at 600 °C, and then analyzed using high-resolution Rutherford backscattering spectrometry using 2 MeV He+ or 100 keV H+. The segregation coefficient k depends strongly on Er concentration. At Er interface areal densities below 6x1013 Er/cm2 nearly full segregation to the surface is observed, with k=0.01. At higher Er densities, segregation and trapping in the crystal are observed, with k=0.20. The results are consistent with a model in which it is assumed that defects in the a-Si near the interface act as traps for the Er.

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Journal J. Appl. Phys.
Citation
Polman, A, Custer, J.S, Zagwijn, P.M, Molenbroek, A.M, & Alkemade, P.F.A. (1997). Segregation and trapping of erbium at a moving crystal-amorphous Si interface. J. Appl. Phys., 81, 150–153.