Abstract

A silicon surface continuously illuminated by a laser forms patterns consisting of distinct regions of solid and melt. These patterns have previously been categorized as having ordered or disordered morphologies.¹ Through the use of two-dimensional Fourier transforms, we have more completely characterized the solidmelt patterns. The Fourier transforms of both morphological types exhibit structures with a characteristic spatial frequency. The transform structures of the disordered patterns exhibit wide spectral widths and no orientational order, distinguishing them from the ordered patterns. The characteristic spatial length associated with the disordered structures is determined by heat flow within the semiconductor. When approaches the wavelength of the incident light, then electrodynamic effects begin to lock in, generating patterns with distinct orientations and spatial periods related to the polarization and wavelength of the laser.

© 1990 Optical Society of America