Microstructural evolution of polycrystalline Si films during Ni-silicide-mediated lateral crystallization of amorphous Si films has been studied. The growth direction of the crystallized needle-like grains was not parallel to the crystallization direction of the film. The grains were aligned nearly parallel to each other and consequently, a macroscopic quasi grain was formed. The dominant growth directions of the needle-like grains with respect to the crystallization direction were +/-(35 +/- 5)degrees and +/-(55 +/- 5)degrees, which were well matched for the growth of {110}-oriented, needle-like grains along the <111> directions with 70degrees branching and 110degrees branching, respectively. The length of the transition region in front of the silicide-mediated lateral crystallization was about 5 mum; thin-film transistors should not be located here because of poor microstructure. (C) 2004 The Electrochemical Society.