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Proceedings Paper

Simulation of picosecond pulsed laser ablation of silicon: the molecular-dynamics thermal-annealing model
Author(s): Patrick Lorazo; Laurent J. Lewis; Michel Meunier
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Paper Abstract

A molecular-dynamics thermal-annealing model is proposed to study the mechanisms of ablation induced in crystalline silicon by picosecond pulses. In accordance with the thermal annealing model, a detailed description of the microscopic processes resulting from the interaction of a 308 nm, 10 ps, Gaussian pulse with a Si(100) substrate has been embedded into a molecular- dynamics scheme. This was accomplished by explicitly accounting for carrier-phonon scattering and carrier diffusion. Above the predicted threshold energy for ablation, Fth equals 0.25 J/cm2, ablation is driven by subsurface superheating effects: intense heating by the pulse leads to the thermal confinement of the laser-deposited energy. As a result, the material is overheated up to its critical (spinodal) point and a strong pressure gradient builds up within the absorbing volume. At the same time, diffusion of the carriers in the bulk leads to the development of a steep temperature gradient below the surface. Matter removal is subsequently triggered by the relaxation the pressure gradient as a large--few tens of nm thick--piece of material is expelled from the surface.

Paper Details

Date Published: 29 May 2001
PDF: 5 pages
Proc. SPIE 4276, Commercial and Biomedical Applications of Ultrashort Pulse Lasers; Laser Plasma Generation and Diagnostics, (29 May 2001); doi: 10.1117/12.428006
Show Author Affiliations
Patrick Lorazo, Ecole Polytechnique de Montreal and Univ. de Montreal (Canada)
Laurent J. Lewis, Univ. de Montreal (Canada)
Michel Meunier, Ecole Polytechnique de Montreal (Canada)


Published in SPIE Proceedings Vol. 4276:
Commercial and Biomedical Applications of Ultrashort Pulse Lasers; Laser Plasma Generation and Diagnostics
Richard F. Haglund; Richard F. Haglund; Richard F. Wood; Joseph Neev; Richard F. Wood, Editor(s)

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