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Proceedings Paper

Electric signal diagnostics of plasma dynamics at an early stage of laser ablation
Author(s): Ming Hui Hong; Yongfeng Lu; A. Foong
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Paper Abstract

Plasma dynamics at early stage of laser ablation is investigated by a tiny metal probe. There are tow negative peaks with different distributions in an electric signal. The first peak has a duration about 50 ns and delays 30 ns with respect to laser irradiation. The waveform and peak maximum position do not change with probe distance. It is attributed to plasma-induced electric field at the early stage. The second peak appears about 250 ns laser with a profile duration higher than 1 microsecond(s) . The peak maximum position moves forward as probe distance reduces due to earlier charge particle arrival of the probe. Experimental results and theoretical model in show that electric signal of plasma-induced electric field is resulted from an electric dipole with negative charge in front. It is constructed by electrons and positive ions emitted at early stage of laser ablation. Dependence of electric signal profile on probe distance, laser fluence and pulse number is studied. The electric signal detection can be used to monitor laser removal of metallic oxide layer in real time. Influence of substrate bias on the signal waveform is also analyzed. It may be applied to modify plasma dynamics and laser ablation.

Paper Details

Date Published: 7 June 2000
PDF: 10 pages
Proc. SPIE 3933, Laser Applications in Microelectronic and Optoelectronic Manufacturing V, (7 June 2000); doi: 10.1117/12.387557
Show Author Affiliations
Ming Hui Hong, National Univ. of Singapore (Singapore)
Yongfeng Lu, National Univ. of Singapore (United States)
A. Foong, National Univ. of Singapore (Singapore)


Published in SPIE Proceedings Vol. 3933:
Laser Applications in Microelectronic and Optoelectronic Manufacturing V
Henry Helvajian; Koji Sugioka; Malcolm C. Gower; Jan J. Dubowski, Editor(s)

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