Plasma-Chemical Etching of Thin Silver Films for Applications of Plasmonics by Inductive-Coupled Argon Plasma

Authors: Filippov I.A., Velikovskiy L.E., Shakhnov V.A. Published: 22.12.2020
Published in issue: #4(133)/2020  
DOI: 10.18698/0236-3933-2020-4-165-180

Category: Instrument Engineering, Metrology, Information-Measuring Instruments and Systems | Chapter: Vacuum and Plasma Electronics  
Keywords: photonics, plasmonics, plasma-chemical etching, technology, simulation

The study focuses on the processes of plasma-chemical etching of silver films for the manufacture of photonic elements --- nanoscale light sources, and examines the theoretical foundations of etching processes and the process of plasma formation in plasma-chemical etching facilities. We assessed the introduced technology when forming topological elements in thin films of silver metal, and identified key problems, such as redeposition and non-volatility of the material. The paper presents the results of simulating the etching process for several critical submicron sizes, and, based on the simulation results, shows the dependences of the etching rates on the power of the plasma sources. The focus is on the formation of holes to create a nanoscale light source. Both positive and negative properties of the plasma-chemical etching method using a source of inductive-coupled plasma are considered, and the features of technological facilities used for these processes are outlined. The process of formation of nanoelements in a silver film and the effect of redeposition of material particles as a result of ion sputtering are considered. We propose a two-stage etching process, which makes it possible to form a vertical profile of the walls of the manufactured elements and to avoid the effect of redeposition. We also give recommendations for the processes of etching through an electron-beam resist in facilities with an inductive-coupled plasma source. By optimizing the thicknesses of the resistive mask and plasma sources, we obtained the results of etching nanoscale elements with preservation of geometric shapes


[1] Claire D., Jean-Luc P. Plasmon lasers: coherent nanoscopic light sources. Phys. Chem. Chem. Phys., 2017, vol. 19, no. 44, art. 29731. DOI: https://doi.org/10.1039/C7CP06780A

[2] Noginov M., Zhu G., Belgrave A., et al. Demonstration of a spaser-based nanolaser. Nature, 2009, vol. 460, pp. 1110--1112. DOI: https://doi.org/10.1038/nature08318

[3] Baburin A.S., Ivanov A.I., Trofimov I.V., et al. Highly directional plasmonic nanolaser based on high-performance noble metal film photonic crystal. Proc. SPIE, 2018, vol. 10672. DOI: https://doi.org/10.1117/12.2307572

[4] Saha S., Chowdhury S., Dutta A., Kildishev A.V., et al. Hybrid photonic-plasmonic waveguides with ultrathin TiN. OSA Tech. Digest, 2019, paper JTh2A.40. DOI: https://doi.org/10.1364/CLEO_AT.2019.JTh2A.40

[5] Krasavin A.V., Zayats A.V. Silicon-based plasmonic waveguides. Opt. Express, 2010, vol. 18, no. 11, pp. 11791--11799. DOI: https://doi.org/10.1364/OE.18.011791

[6] Gosciniak J., Rasras M. High-bandwidth and high-responsivity waveguide-integrated plasmonic germanium photodetector. J. Opt. Soc. Am. B, 2019, vol. 36, no. 9, pp. 2481--2491. DOI: https://doi.org/10.1364/JOSAB.36.002481

[7] Melikyan A., Lindenmann N., Walheim S., et al. Surface plasmon polariton absorption modulator. Opt. Express, 2011, vol. 19, no. 9, pp. 8855--8869. DOI: https://doi.org/10.1364/OE.19.008855

[8] Markov A., Reinhardt C., Ung B., et al. Photonic bandgap plasmonic waveguides. Opt. Lett., 2011, vol. 36, no. 13, pp. 2468--2470. DOI: https://doi.org/10.1364/OL.36.002468

[9] Messner A., Eltes F., Ma P., et al. Leuthold, integrated ferroelectric plasmonic optical modulator. OSA, 2017, paper Th5C.7. DOI: https://doi.org/10.1364/OFC.2017.Th5C.7

[10] Zaki A.O., Kirah K., Swillam M.A. Hybrid plasmonic electro-optical modulator. Appl. Phys. A, 2016, vol. 122, art. 473.

[11] Baburin A.S., Merzlikin A.M., Baryshev A.V., et al. Silver-based plasmonics: golden material platform and application challenges [Invited]. Opt. Mater. Express, 2019, vol. 9, no. 2, pp. 611--642. DOI: https://doi.org/10.1364/OME.9.000611

[12] Kenro M. Fundamentals of plasma physics and controlled fusion. NIFS-PROC-48. Tokyo, National Institute of Fusion Science, 2000.

[13] Boris D.R. Electron beam generated plasmas produced in fluorine-containing gases: characterizing plasma parameters. 62nd AVS Symp., 2015. DOI: https://doi.org/10.13140/RG.2.1.2741.5288

[14] Shearn M., Sun X., Henry M.D., et al. Advanced plasma processing: etching, deposition, and wafer bonding techniques for semiconductor applications. In: Semiconductor technologies. IntechOpen, 2010, pp. 79--104. DOI: https://doi.org/10.5772/8564

[15] Choi T., Hess D.W. Chemical etching and patterning of copper, silver, and gold films at low temperatures. ECS J. Solid State Sc. Technol., 2015, vol. 4, no. 1, pp. 3084--3093. DOI: https://doi.org/10.1149/2.0111501jss

[16] Smirnov Yu.N., Filippov I.A., Zverev A.V. [Technology of nanoscale structures formation by plasma-chemical etching methods for nanoplasmonics products]. Vseros. nauch.-tekh. konf. "Studencheskaya nauchnaya vesna: Mashinostroitel’nye tekhnologii" [Rus. Sc.-Tech. Conf. "Students Scientific Spring: Machine Engineering Technologies"], 2016 (in Russ.). Available at: http://studvesna.ru/?go=articles&id=1557 (accessed: 15.06.2020).

[17] Lee. Y.J., Park S.D., Song B.K., et al. Characteristics of Ag etching using inductively coupled Cl2-based plasmas. Jpn. J. Appl. Phys., 2003, vol. 42-1, no. 1, pp. 286--290. DOI: https://doi.org/10.1143/JJAP.42.286

[18] Rodionov I.A., Baburin S.A., Zverev A.V., et al. Mass production compatible fabrication techniques of single-crystalline silver metamaterials and plasmonics devices. Proc. SPIE, 2017, vol. 10343. DOI: https://doi.org/10.1117/12.2271643