SINGLE-CRYSTAL SI FILMS FOR THIN-FILM-TRANSISTOR DEVICES

The fact that single-crystal Si would make an ideal material for thin- film transistor devices has long been recognized. Despite this awarene ss, a viable method by which such a material could be directly produce d on a glass substrate has never been formulated. In this letter, it i s shown experimentally that location-controlled single-crystal Si regi ons on a SiO2 surface can be obtained in a glass-substrate compatible manner, via excimer-laser-based sequential lateral solidification of t hin Si films using a beamlet shape that self-selects and extends a sin gle grain over an arbitrarily large area. This is accomplished by cont rolling the locations, shape, and extent of melting induced by the inc ident excimer-laser pulses, in such a manner as to induce interface-co ntour-affected sequential super-lateral growth of crystals, during whi ch the tendency of grain boundaries to align approximately orthogonal to the solidifying interface is systematically exploited. (C) 1997 Ame rican Institute of Physics.