Behaviors in the melting-solidification process of float-zone silicon (Fz-Si) were examined by in-situ high-resolution transmission electron microscopy (HRTEM). Point defect clusters were observed to form at high temperatures. {1 1 1} liquid-solid interfaces were confirmed to proceed by the lateral movement of a pair of steps having several atomic heights, while {1 0 0} liquid-solid interfaces were flat and moved between both end facets. A crystallized {1 1 1} liquid-solid interface was observed at about 20 layers. A twin band was observed at an interface close to silicide formed by surface diffusion. (C) 2002 Elsevier Science B.V. All rights reserved.