Effect of annealing temperature on optical and structural properties of ion-beam-synthesize semiconducting FeSi2 layers

Both as-implanted and annealed ion-beam-synthesized semiconducting FeSi2 layers on Si(001) substrates have been investigated by optical transmission measurements and transmission electron microscopy. The effect of annealing temperature on the minimum direct band gap and the Urbach tail width was found to be associated with the growth of beta grains, the formation of a well-defined polycrystalline layer, and the removal of implantation-induced damage during the subsequent thermal annealing. The direct band gap and the Urbach tail width in the sample first annealed at a temperature to produce a metallic alpha phase, followed by a prolonged annealing at a temperature to produce a beta phase, were also studied. (C) 1996 American Institute of Physics.