High-quality polycrystalline silicon layers grown on dissimilar substrates from metallic solution

We prepared polycrystalline silicon layers on quartz glass and glassy carbon substrates using liquid phase epitaxy at temperatures below 920°C. Before epitaxial growth, the substrate surfaces were coated with a 10 to 25 μm thick silicon seed layer which we obtained by ion beam-assisted plasma deposition from a SiH₄/H₂ gas mixture. The grains of these layers reached sizes up to 1 pm and had a preferential orientation in [111] direction with respect to the substrate. On the seed layer, a polycrystalline Si layer has been grown from solution. The Si crystals grew individually and had an average size of several ten μm. Apart from twins the Si crystals were almost defect-free. Coalescences of the individual crystals with grain boundaries between them result in good lateral connections over the layer area of 4 cm². The results of the electrical characterization show that the layers are suitable for photovoltaic application