CHARACTERIZATION OF IN-SITU TIME-RESOLVED OPTICAL SPECTRA DURING EXCIMER-LASER CRYSTALLIZATION

摘要

A real-time in-situ time-resolved (～1 ns) optical reflectivity and transmission (TRORT) measurement system combining two He-Ne probe lasers, a digital oscilloscope, and three fast photodiodes is developed to investigate the rapid phase-change processes of Si thin films during the excimer-laser crystallization (ELC). The changes in both reflectivity and transmission of Si thin films during ELC are recorded by the TRORT measurement system. Melting and resolidification behaviors of Si thin films during ELC are interpreted. The fall time of liquid Si is reduced with increase in the excimer-laser energy density, while the rise time of liquid Si remains approximately constant at 5 ns. The first small peak in the reflectivity spectrum is proved to be not a phenomenon of explosive crystallization.