Positive- and negative-tone structuring of crystalline silicon by laser-assisted chemical etching

M. Chambonneau (1) , X. Wang (2) , X. Yu (2, 3) , Q. Li (1) , D. Chaudanson (4) , S Lei (2) , D. Grojo (1)

1 LP3 - Laboratoire Lasers, Plasmas et Procédés photoniques
2 Kansas State University
3 CREOL - Center for Research and Education in Optics and Lasers
4 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

We demonstrate a structuring method for crystalline silicon using nanosecond laser internal irradiation followed by chemical etching. We show a dramatic dependence of the etch rate on the laser-writing speed. Enhanced isotropic etch rates of silicon by laser-induced internal damage were recently demonstrated with strong acids, but our results add the possibility to obtain reduced etch rates leading to different topographies. Material analyses indicate the possibility to efficiently produce high-aspect ratio channels, thanks to laser-induced porosities, as well as silicon micro-bumps due to highly stressed regions. This holds promises for fabricating microfluidic, photovoltaic, and micro-electromechanical systems.

Keywords: Laser sources; Micro Raman spectroscopy; Negative refractive index; Phase shift; Refractive index; Scanning electron microscopy

Domains: Optics [physics.optics]; Optics / Photonic

M. Chambonneau, X. Wang, X. Yu, Q. Li, D. Chaudanson, et al.. Positive- and negative-tone structuring of crystalline silicon by laser-assisted chemical etching. Optics Letters, 2019, 44 (7), pp.1619-1622. ⟨10.1364/OL.44.001619⟩. ⟨hal-02106462⟩