Crystallization of amorphous silicon thin-film on glass substrate preheated at 650 degrees C using Xe arc flash of 400 mu s

Abstract

Experimental and theoretical investigations on flash lamp annealing (FLA) of amorphous silicon (a-Si) film on glass were carried out with a view to practical applications in large-window display industries. A Xe arc flash lamp of 950 mm in length and 22 mm in bore diameter was applied with nominal input voltage of 7 kV and flash duration of 400 mu s. Prior to the annealing process, the specimen for FLA was preheated at 650 degrees C, which was very close to the service temperature of the glass specimen used in this study. By employing a focusing elliptic reflector, maximum light energy density of up to 8.4 J/cm(2) could be attained with an active exposure width of 2 cm. Crystallization of a-Si could be achieved in solid-phase by applying a flash beam with light density of at least 5 J/cm(2), and its phase-transition characteristics that varied with energy densities could be explained by theoretically estimated temperature fields. Electron microscopy observations confirmed that solid-phase crystallization preceded melting of a-Si due to relatively long flashing (heating) duration of 400 mu s, which was comparable to solid-phase crystal-growth times at elevated temperatures. (C) 2012 Elsevier B.V. All rights reserved.