(The) generation of periodic ripples on silicon by pulsed ruby laser

Abstract

The periodic ripple structures were produced on single (100) crystal of silicon by mode-locked or conventional mode pulses from ruby laser. In mode-locked operation of laser, the spatial periods of ripples were $0.7\mu m,\; 1.4 \mu m,\; 0.9 \mu m$ at incident angle $0\,^\circ,\; 30\,^\circ,\; 45\,^\circ$, respectively. These values were in good agreement with the usual surface scattered wave model. In conventional mode operation, linear and circular ripples with spatial periods $4.5 \mu m$ and $6 \mu m$ at near normal incidence were produced and the results are consistent with the laser-acoustic mode coupling model.