Effects of parameters in femtosecond laser micromachining on ablation of silicon

Abstract

A series of ablation experiments on silicon surface by femtosecond laser system of 775 nm and 150 fs duration pulses were carried out. The morphological characteristics and the associated effect in the ablation were tested by atomic force microscope (AFM), scanning electron microscope (SEM), focused ion beam (FIB), and the optic microscope. The single pulse threshold can be obtained directly. For the multiple pulses, the ablation threshold varies with the number of pulses applied to the surface due to the incubation effect. By analyzing the experimental data, the thresholds of laser fluences under various laser pulse numbers were obtained, and the relationships between ablation area and laser energy and laser pulse number were concluded. Meanwhile, the periodic ripple structure on silicon surface was found. Under the condition of certain laser power, the number of laser pulse can influence the formation of ripples.

Keywords

femtosecond pulse laser / microstructure machining / silicon / ablation threshold / incubation effect

References

[1] Jia W., Wang Q., Fu X., et al. Progress of femtosecond laser micromachining[J]. Chinese Journal of Quantum Electronics, 2004, 21(2): 194-201.

[2] Riedel D., Hernandez-Pozos J. L., Palmer R. E., et al. Fabrication of ordered arrays of silicon cones by optical diffraction in ultrafast laser etching with SF6[J]. Appl Phys A, 2004, 78(3): 381-385.

[3] Barsch N., Korber K., Ostendorf A., et al. Ablation and cutting of planar silicon devices using femtosecond laser pulses[J]. Appl Phys A, 2003, 77(2): 237-242.

[4] Simon P., Ihlemann J. Ablation of submicron structures on metals and semiconductors by femtosecond UV-laser pulses[J]. Applied Surface Science, 1997, 109/110 25-29.

[5] Ni X., Wang Qingyue. Research progress of femtosecond laser ablation[J]. Laser and Optoelectronics Progress, 2002, 39(12): 4-9.

[6] Parsons-Karavassilis D., Jones R., Cole M. J., et al. Diodepumped all-solid-state ultrafast Cr:LiSGAF laser oscillator-amplifier system applied to laser ablation[J]. Opt Commun, 2000, 175 389-396.

[7] Chien C. Y., Gupta M. C. Pulse width effect in ultrafast laser processing of materials[J]. Appl Phys A, 2005, 81(6): 1257-1263.

[8] Liu X., Du D., Mourou G. Laser ablation and micromachining with femtosecond laser pulses[J]. Proc SPIE, 2000, 4087 1194-1200.

[9] Miyamoto I., Lu Y. F., Sugioka K., et al. Morphological characterization of various kinds of materials in femtosecond-laser micromachining[J]. Proc SPIE, 2002, 4426 86-89.

[10] Mannion P. T., Magee J., Coyne E., et al. The effect of damage accumulation behaviour on ablation thresholds and damage morphology in ultrafast laser micro-machining of common metals in air[J]. Applied Surface Science, 2004, 233 275-287.

[11] Bonse J., Boudach S., Krüger J., et al. Femtosecond laser micromachining of technical materials[J]. Proc SPIE, 2000, 4046 161-172.

[12] Bonse J., Baudach S., Krüger J., et al. Femtosecond laser ablation of silicon-modification thresholds and morphology[J]. Appl Phys A, 2002, 74(1): 19-25.