PICOSECOND LASER ANNEALING OF IMPLANTED Si AND GaAs : A COMPARATIVE STUDY WITH A RAMAN MICROPROBE

Abstract

The transformation of implanted amorphous Si and GaAs induced by a single pulse of a picosecond laser is studied. In both materials a clear multiannular pattern was produced by the irradiation. The different patterns have been investigated by scanning the surface with a 1 µm spatial resolution Raman microprobe. Sharp transitions between amorphous and cristalline rings are observed for Si. In GaAs the transitions are smoother beetween nearly amorphous and nearly crystalline rings. A multiple melting-resolidification process within the laser pulse duration could explain the formation of these patterns

Phase transformations of an InSb surface induced by strong femtosecond laser pulses

“…The conditions for the onset of permanent laser-induced changes of the reflectivity are more consistent with a laserproduced amorphization of the surface layer than with an appearance of a metastable centrosymmetric metallic phase. However, in order to make a final conclusion, the structure of the phase with a permanently high reflectivity which is produced on the surface of InSb by a femtosecond-laser excitation should be studied directly by using other structuresensitive techniques, for example, by Raman microprobe analysis, 30 or particle scattering, or x-ray diffraction.…”