Erlangen 2022 – scientific programme
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K: Fachverband Kurzzeit- und angewandte Laserphysik
K 6: Laser-Beam Matter Interaction - Laser Applications I
K 6.2: Talk
Thursday, March 17, 2022, 11:00–11:15, K-H4
Spatially intensity profiles shaping of ultra-short laser for enhanced selective thin film test structure processing on silicon multilayers — •Stephan Krause1,2, Stefan Lange2, Hardik Vaghasiya1,2, Christian Hagendorf2, and Paul-Tiberiu Miclea2,1 — 1Centre for Innovation Competence SiLi-nano, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany — 2Fraunhofer Center for Silicon Photovoltaics CSP, Halle (Saale), Germany
In this work, we applied spatially shaped ultra-short pulses for laser micro-machining on SiNx/c-Si layer system for the investigation of the selectivity ablation behavior of the sub-µm thick SiNx top layer. By the comparison to gaussian beams, intensity spatially shaped pulses have the potential for a minimization of the superfluous energy in the peak region over the ablation threshold fluence as well as a steeper intensity drop at the side edge of the pulses. This can lead to more precise lateral and vertical ablation properties of the top thin film layer and lower modification/damage to the silicon substrate and the adjacent region. We compare ablation thresholds variations due to beam shaping via light microscopic measurements on the µm-laser spot structures as well as the crystalline phases and stress modification via µ-Raman in the ablated spot, adjacent modified regions and untreated reference areas.