Melting and crystallization behavior of low-pressure chemical-vapor-deposition amorphous Si films during excimer-laser annealing

Results are presented of cross-sectional transmission-electron microscopy and time-resolved optical reflectivity investigations into the excimer-laser annealing of low-pressure chemical-vapor-deposition amorphous Si films. It is found that, in the initial stages of the laser pulse, a thin surface layer melts. This is directly followed by explosive crystallization of the film into to small, columnar, and defect-rich grains. As more laser energy is consumed, the Si film melts in from the surface for a second time, eventually leading to complete melting of the film. It is argued that melting along grain boundaries and defects is a crucial step in obtaining large, single-crystalline grains in the super-lateral growth regime.