Orientation-controlled nucleation of crystal silicon grains in amorphous silicon on a rolled nickel tape substrate

Abstract

Crystal silicon grains with grain sizes in excess of 10 mum and orientation control over all three directions were produced by depositing an amorphous silicon thin film on a cold-rolled and annealed nickel tape and annealing at 600 degreesC for 2 h. The needle-like morphology of the grains indicated that the crystallization was mediated by NiSi2. All grains had their [110] axis about 21 degrees off the surface normal. Furthermore, nearly all of them had the same rotation about the [110] axis except for presence of twins and/or type A-B formations. Despite the use of the nickel substrate, the Ni concentration within the Si film was below the detection limit of energy-dispersive x-ray spectroscopy (10(19) cm(-3)). This low-Ni contamination level is attributed to the presence of an oxide layer between the Ni substrate and the Si film. (C) 2001 American Institute of Physics.