High-temperature induced nano-crystal formation in ion beam-induced amorphous silicon ripples
J. Grenzer and A. Mucklich
Forschungszentrum Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, P.O.Box 510119, 01314 Dresden, Germany

S. Grigorian and U. Pietsch
University of Siegen, Institute of Physics, 57072 Siegen, Germany

D. P. Datta, T. K. Chini, S. Hazra, and M. K. Sanyal
Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India

We report on in-situ investigations of a recrystallization process of amorphous and damaged crystalline parts generated during ion-beam induced rippling on a Si(100) surface. The ripple structure was created by 60 keV 40Ar+ irradiation with a dose of 5 x 1017 ions/cm2 at ion incident angle of 60o with respect to the surface normal. At this dose the ripples have an average spatial periodicity of about 715 nm and surface undulations with an amplitude of about 40 nm. Structure and morphology of ripples were studied by two types of X-ray scattering (grazing incidence diffraction and amorphous scattering) methods, transmission electron microscopy and atomic force microscopy. X-ray grazing-incidence amorphous scattering pattern were recorded in-situ for a temperature range from 250 to 750 oC. Up to about 500 oC mainly we found a single broad scattering maximum corresponding to the Si(111) inter-planar distances. At higher temperature these peaks become sharp and intense indicating the onset of a re-crystallization process in the amorphous top layer. Two processes were found, a formation of crystalline islands on top of the former amorphous surface ripples and a growth of polycrystalline twins close to the former amorphous-crystalline interface.