A thin palladium layer (∼40 A˚) was selectively formed on top of amorphous silicon films before annealing and the effects of palladium layer on the crystallization behavior of the amorphous silicon films were investigated. It was observed that the amorphous silicon right under the Pd layer could be crystallized to grain sizes of several hundred angstroms by annealing at 500 °C. In addition, the area between the Pd thin pads, patterned by lithography, was found to be crystallized to grain sizes of a few tens of microns in length by the same annealing. Such lateral crystallization was found to reach more than 100 &mgr;m in some cases. The lateral crystallization phenomenon might be useful for the fabrication of low temperature polycrystalline‐Si thin film transistors, providing large‐grained Si films. ©1995 American Institute of Physics.