Recrystallization of polycrystalline silicon (poly-Si) film by excimer laser annealing (ELA) is discussed by considering the experimental results that the three stages of nucleation, textured grain growth and secondary grain growth were observed. Although the phenomenon of nucleation in the amorphous silicon (a-Si) is understood by considering crystallization from the super cooled liquid, the growth mechanisms of the textured grain and secondary grain are not understood by this, because the melting point of poly-Si which has already been formed on the entire surface during these growth stages is higher than that of a-Si. The recrystallization mechanism considering the dislocation movement is introduced to investigate the present phenomenon. It also clarifies the reason why secondary grain growth occurs under the critical conditions of laser irradiation energy and shot number. The feasibility of nucleation through the super cooled liquid is also discussed.

Characteristics of polycrystalline silicon (poly-Si)film prepared by excimer laser annealing was examined. The crystallinity increases as increasing the laser energy density and the number of shot. The secondary grain growth occurs at the laser energy density and the number of shot larger than the critical values. The crystallinity of the poly-Si with dehydrogenation prior to the laser irradiation is better than that with non-dehydrogenation. Its surface roughness becomes same as or better than that with non-dehydrogenation.

This paper examines the characteristics of the poly-Si grains formed by ELA with the energy density from 75 mJ/ cm2 to 400 mJ/cm2, and discusses the change of the crystal growth mechanism of the recrystallized poly-Si dependent on the energy density. For the energy density from 250 mJ/cm2 to 350 mJ/ cm2 , the disk-shaped grains are observed. The dependences of the area ratio of disk-shaped grain both on the energy density and on the shot number are examined. From these results, the role of the disk-shaped grains for the change of the crystal growth mechanism dependent on the energy density is clarified.

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