In situ visualization of interface dynamics during the double laser recrystallization of amorphous silicon thin films

A new double laser recrystallization technique utilizing a temporally modul ated continuous wave (CW) Ar+ laser in conjunction with a superposed KrF ex cimer laser has been shown to achieve lateral grain growth on amorphous sil icon (a-Si) thin films. In the present investigation, instead of excimer la ser, a more adaptable frequency-doubled Q-switched Nd:YLF laser (wavelength lambda= 524 nm) is utilized. Lateral grains of larger than 20 mum are obta ined in 50 nm-thick a-Si films. In order to understand the recrystallizatio n mechanism, high-resolution laser flash photography employing a nitrogen l aser-pumped dye laser (lambda = 445 nm, full-width-half-maximum pulse durat ion FWHM = 2 ns) as illumination source enables in situ direct visualizatio n of the resolidification process for the first time. The images reveal lat eral solidification velocity of about 10 m/s. The nuclei created by the Nd: YLF laser and the reduction in cooling rate by the Ar+ laser are important for inducing long lateral grains. (C) 2001 Elsevier Science B.V. All rights reserved.