PHASE-TRANSFORMATION IN AMORPHOUS-SILICON UNDER EXCIMER-LASER ANNEALING STUDIES BY RAMAN-SPECTROSCOPY AND MOBILITY MEASUREMENTS

The transformation of silicon from an amorphous phase to a polycrystal line phase by excimer laser annealing was investigated by means of Ram an spectroscopy and electron mobility measurements, It was shown that the phase transformation was mainly governed by the energy density of the laser, and that when the density was high enough to evaporate the surface layer of the amorphous silicon, a latent state of the multiple irradiated sample was formed, where the Raman intensity exceeded that of the bulk crystal silicon and the electron mobility of the film bec ame very high. This observation was explained by the pyramidal grain g rowth structure of the crystalline silicon. The amorphous component at the grain boundary was also observed in measured Raman spectra and it was shown that the presence of this phase had a significant influence on reducing the field effect mobility (C) 1996 American Institute of Physics.