Excimer-laser-induced micropatterning of silicon dioxide on silicon substrates

Highly resolved micropatterns induced on SiO₂-coated Si sample surfaces have been investigated using a KrF excimer laser (λ: 248 nm and τ: 23 ns). Uniform micropatterns were observed to form in the oxide layer after laser-induced melting of interfaces. The pattern size can be controlled either by the laser parameters or even by the oxide layer thickness. SEM analysis identified that the micropatterns were virtually initiated at the molten interface and the oxide layer followed the interface patterning to change its profile. Simulation of laser interaction with double-layered structures indicated that the oxide layer could melt or be ablated due to interface superheating when it was deposited on a highly absorbing Si substrate. IR analysis has demonstrated that the structural properties of the SiO₂ layer undergo no appreciable changes after laser radiation. This process provides a possible basis for its application in micropatterning of transparent materials using excimer lasers.