THEORETICAL AND EXPERIMENTAL STUDIES OF A-SI-H RECRYSTALLIZATION BY XECL EXCIMER-LASER IRRADIATION

Studies of phase transitions in amorphous hydrogenated silicon (a-Si:H ) thick films (2-4 mu m) caused by XeCl laser irradiation, with the pu lse energy density above the melting threshold of a-Si:H but below the threshold of monocrystalline silicon (c-Si), are presented. A mathema tical model of non-equilibrium phase changes, including crystallizatio n in the solid state, is formulated. Time-resolved reflectivity (TRR) measurements are performed to monitor the appearance and time evolutio n of various phases during the irradiation. The final structure is stu died using scanning electron microscopy (SEM). The theoretical and exp erimental results are analyzed from the point of view of the polycryst alline silicon (pc-Si) grain size, and the sequence of the phase chang es during the irradiation is found. The theoretical simulation is in g ood agreement with the experimental observations as well as with the d ata previously published by other authors.