Microstructuring of silicon with femtosecond laser pulses

Abstract:

We report that silicon surfaces develop an array of sharp conical spikes when irradiated with 500 laser pulses of 100-fs duration, 10-kJ/m2 fluence in 500-torr SF6 or Cl2. The spikes are up to 40-m tall, and taper to about 1-m diameter at the tip. Irradiation of silicon surfaces in N2, Ne, or vacuum creates structured surfaces, but does not create the sharp conical spikes.