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HL: Halbleiterphysik
HL 21: Amorphe Halbleiter
HL 21.12: Talk
Tuesday, March 18, 1997, 18:45–19:00, H4
Laser interference crystallization of amorphous germanium — •M. Mulato1,2, D. Toet1, G. Aichmayr1,3, P.V. Santos1, and I. Chambouleyron2 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart — 2Instituto de Física Gleb Wataghin, Unicamp, 13083-970 Campinas-SP, Brazil — 3Institut für Physikalische Elektronik, Universität Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart
Laser interference crystallization (LIC) is a powerful structuring tool for the ’in-situ’ fabrication of periodic arrays of submicrometer polycrystalline microstructures. We investigated the LIC of a-Ge and a-Ge:H samples using single pulses from a frequency doubled Nd:YAG laser (λ=532nm, pulse width=7ns). The kinetics of the crystallization process was investigated by time resolved reflection measurements. By interfering two (three) laser beams on the surface of the samples, we obtained line (dot) arrays of polycrystalline germanium (with periods between 2.5 and 3.5 µm) at the interference maxima. Micro-Raman spectroscopy results (0.7µm lateral resolution) indicate that the crystallized material is under extensive stress and evidence a dependence of the crystallite size on laser intensity, the maximum size being about 5 nm. Explosive crystallization, which has been reported for a-Ge, does not hinder the laser-induced structuring of this material.