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DS: Fachverband Dünne Schichten

DS 39: Layer Deposition Processes & Layer Growth

DS 39.1: Vortrag

Donnerstag, 25. März 2010, 17:00–17:15, H8

Twin assisted growth of silicon on glass from low temperature solution and the onset of a morphological instability — •Robert Heimburger, Thomas Teubner, Nils Deßmann, Torsten Boeck, and Roberto Fornari — Leibniz–Institut für Kristallzüchtung, Max–Born–Straße 2, 12489 Berlin

Low temperature solution growth of microcrystalline silicon on glass substrates is considered in the light of supersaturation conditions and underlying growth mechanisms.
Silicon crystallites grown from liquid indium by means of steady–state solution growth at 600^∘C are terminated by {111} facets. Often, individual grains consist of one or more Σ3 twin–boundaries. Alternating ledges and reentrant edges formed at multiple twin boundaries are found to locally enhance growth rate leading to anisotropic platelike structures. This can be explained by the presence of a self–preserving elementary step at the reentrant edges enabling fast growth even at low supersaturation without the need for 2D–nucleation. Additionally, if the size of a perfect crystal exceeds a certain value, the formation of hoppers in the middle of {111} facets is observed. This morphological instability is interpreted by means of a supersaturation inhomogeneity arising within the diffusion boundary layer of the nutrient solution which causes solute depletion at the center of growing facets. As crystals exceed a critical size, this depletion cannot be longer compensated by an increased interstep distance. This leads to a significant decrease of growth rate at the centers.