Excimer-laser ablation and micro-patterning of ceramic Si3N4
N4 has been investigated. The ablation threshold in air, Φth, is around 0.3±0.1 J/cm2 with ArF- and 0.9±0.2 J/cm2 with KrF-laser radiation. With fluences Φth<Φ<4 J/cm2 the irradiated surface is either very flat or it exhibits a cone-type structure, depending on the number of laser pulses employed. With fluences of 5 to 10 J/cm2, the sample surface becomes very smooth, much smoother than the original mechanically polished surface. Pores, scratches, and cracks observed on the non-irradiated surface are absent within the illuminated area. In this regime, the ablation rates are typically 0.1 to 0.2 μm/pulse.
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