The effects of extended heat treatment on Ni induced lateral crystallization of amorphous silicon thin films

The effects of extended heat treatment on the rate of metal induced lateral crystallization (MILC) of amorphous silicon (a-Si) were investigated. Orientation image microscopy and transmission electron microscopy were employed to reveal the crystallinity of the thin film and to measure the MILC length. It was found that for circular Ni disc patterns, the radial dimensions of the resulting MILC rings increased with the radii of the Ni discs. The longest MILC lengths were obtained from straight-edged Ni patterns, which effectively had infinite radii of curvature. The MILC rate decreased upon extended heat treatment. One reason is the continuously changing state of the a-Si during the treatment. An additional reason could be the diminishing supply of Ni from the Ni covered area. The contribution of both to the reduction of the MILC rate is discussed.