Preparation of single crystalline regions in amorphous silicon layers on glass by Ar+ laser irradiation

By melting amorphous silicon layers on glass by the beam of an Ar+ laser, l arge grained polycrystalline films as well as single crystalline regions at predefined positions were generated. If the layers are crystallized by scanning a circular laser beam at a rate of up to 5 cm/s the crystal size depends on the overlap between successive scanning traces. The lateral dimensions of the crystals exceed several 10 m u m for an overlap slightly above 50%. Crystals with size dimensions of abo ut 100 mu m were produced by line scanning of a focused laser beam. Large single crystals were obtained by scanning a sickle-shaped or L-shaped beam profile. If the laser is switched on and off repeatedly, single cryst alline regions are produced at predefined positions. (C) 2000 Published by Elsevier Science B.V. All rights reserved.