Crystallization of amorphous silicon thin-film on glass substrate preheated at 650 °C using Xe arc flash of 400 μs

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 μs. Prior to the annealing process, the specimen for FLA was preheated at 650 °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/cm2 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/cm2, 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 μs, which was comparable to solid-phase crystal-growth times at elevated temperatures.

► Flash lamp annealing of amorphous silicon (a-Si) on glass for large-scale displays ► Xe-arc flash lamp of 950 mm in length and 22 mm in bore diameter ► Flash duration of 400 μs at nominal input voltage of 7 kV ► Solid-phase crystallization precedes melting of a-Si due to long flashing duration.