Order-Disorder Transition in Single-Crystal Silicon Induced by Pulsed uv Laser Irradiation

Single-crystal silicon samples have been made disordered by irradiation with pulses from a frequency-quadrupled neodynium-doped-yttrium-aluminum-garnet laser with ${10}^{-8\mathrm{}}$-s pulse length. We have studied the resulting amorphous layer by transmission electron microscopy and He-ion backscattering. Irradiation with longer-wavelength pulses restored the disordered layer to its original crystalline state. This order-disorder laser-radiation-induced transition is repeatable.