Epitaxial alignment of polycrystalline Si films on (100) Si

We demonstrate that fine-grained polycrystalline Si films obtained by chemical vapor deposition can be aligned expitaxially with respect to the underlying (100) Si substrate upon furnace annealing at temperatures of 1000–1150 °C. The alignment proceeds basically by the formation of epitaxial columns which subsequently grow laterally to consume the remaining polycrystalline Si. The rates of alignment are measured to be 20–200 Å/min in the temperature interval of annealing with an activation energy of 4.7 eV. The epitaxial layers so obtained are of reasonably good crystal quality and contains only a small amount of planar crystallographic defects.