Evolution of silicon surface microstructure induced by Nd:YAG nanosecond laser

Abstract

We investigate the evolution of surface microstructure created on single crystal silicon wafer by irradiation of cumulative Nd:YAG nanosecond laser pulses (wavelength 532 or 355 nm) in vacuum. The wavy structures are formed on silicon surface by 532 or 355 nm laser on early stage of laser pulse irradiation, and nearly concentric but slightly disordered semi-circular rings are formed under 355 nm laser pulse irradiation. With the number of laser pulses increasing, the structures gradually evolved into the concave-convex structures which are similar to the beads. And finally quasi-ordered arrays of conical spikes are formed. The growth of these microstructures depends on the capillary waves and self-organization of structures. We find that the cross-ring structures are caused by the superposition of some wavy structures created by capillary waves in the process of 355 nm laser pulses irradiation.