CC BY
27LP-I-15
Thermochemical laser-induced periodic structures formation on metals and semiconductors surfaces
A. Dostovalov1,2, K. Bronnikov1,2, K. Okotrub3, V. Terentyev1, T.J.Y. Derrien4, S. Lizunov4, T. Mocek4, V. Korolkov5, N. M. Bulgakova4, S. Babin12
institute of Automation andElectrometry SB RAS, Fiber optics lab, Novosibirsk, Russian Federation
2Novosibirsk State University, The Department of Physics, Novosibirsk, Russian Federation 3Institute of Automation and Electrometry SB RAS, Laboratory of Condensed Matter Spectroscopy, Novosibirsk, Russian Federation
4HiLASE Centre, Institute of Physics of the Czech Academy of Sciences, Dolni Brezany, Czech Republic
5Institute of Automation and Electrometry SB RAS, Laboratory of Diffraction Optics, Novosibirsk, Russian Federation
The formation of thermochemical laser-induced periodic surface structures (TLIPSS) featured by high ordering in contrast to the ablative structures was recently demonstrated [1]. These structures are formed due to the oxidation of the metal surface illuminated with ultrashort laser pulses and are characterized by the elevation of the relief, forming parallel oxide protrusions. In contrast to the more studied ablative LIPSS, they are oriented parallel to the polarization of incident radiation and highly uniform over the period and height.
The results of TLIPSS formation on chromium films with a thickness of df = 28 ^ 350 nm, a Gaussian laser beam with a wavelength X = 1026 nm, a pulse duration of 232 fs, a repetition rate of 200 kHz was obtained. The growth of the structures period from 678 nm to 950 nm with increasing film thickness was found [2]. It was also observed that with increasing vs up to several hundred p,m/s, the formation of the main structure with a period of the order of X is replaced by the formation of a structure with a period of ~ 200-250 nm, oriented perpendicular to the polarization of the radiation.To explain formation of the LIPSS, a rigorous numerical approach for modeling surface electromagnetic waves in thin-film geometry has been developed [3]. The TLIPSS fabrication productivity increase by 2 orders of magnitude on chromium films with an astigmatic Gaussian beam in comparison with a radially symmetric Gaussian beam is demonstrated [4].
Also, the results of TLIPSS formation on silicon films with a thickness of df = 60 ^ 370 nm, at processing speeds vs = 1 ^ 100 ^m/s, will be presented. On thin films (df = 60 and 100 nm), an ordered structure with a period of ~ 700 nm and orientation along the polarization of the incident radiation is observed at vs < 5 p,m/s. With increasing thickness, the period increases to ~ 1 p,m (d=180 nm), and an ordered structure is formed at vs < 25 p,m/s. With a further increase in thickness, the period of structures formed on films with df =300 and 370 nm does not change significantly and at low scanning speeds of 1-5 p,m/s has a different morphology from previous cases (Fig. 1).
Fig. 1.
References
[1] B. Oktem, I. Pavlov, S. Ilday, H. Kalaycioglu, A. Rybak, S. Yava§, M. Erdogan, and F. O. Ilday, "Nonlinear laser lithography for indefinitely large-area nanostructuring with femtosecond pulses," Nat. Photonics 7, 897-901 (2013).
[2] A. V. Dostovalov, V. P. Korolkov, K. A. Okotrub, K. A. Bronnikov, and S. A. Babin, "Oxide composition and period variation of thermochemical LIPSS on chromium films with different thickness," Opt. Express 26, 7712-7723 (2018).
[3] A.V. Dostovalov, T. J.-Y. Derrien, S.A. Lizunov, F. Peucil, K.A. Okotrub, T. Mocek, V. P. Korolkov, S. A. Babin, N.M. Bulgakova, "LIPSS on thin metallic films: New insights from multiplicity of laser-excited electromagnetic modes and efficiency of metal oxidation," Applied Surface Science, (2019) (in press).
[4] A. V. Dostovalov, K. A. Okotrub, K. A. Bronnikov, V. S. Terentyev, V. P. Korolkov, and S. A. Babin, "Influence of femtosecond laser pulse repetition rate on thermochemical laser-induced periodic surface structures formation by focused astigmatic Gaussian beam," Laser Phys. Lett. 16, 026003 (2019).
