High-Quality Dry Etching of LiNbO3 Assisted by Proton Substitution through H2-Plasma Surface Treatment

Aryal, Arjun; Stricklin, Isaac; Behzadirad, Mahmoud; Branch, Darren W.; Siddiqui, Aleem; Busani, Tito

doi:10.3390/nano12162836

High-Quality Dry Etching of LiNbO3 Assisted by Proton Substitution through H2-Plasma Surface Treatment

Journal Article · Thu Aug 18 00:00:00 EDT 2022 · Nanomaterials

DOI:https://doi.org/10.3390/nano12162836· OSTI ID:1882440

; Stricklin, Isaac; Behzadirad, Mahmoud; Branch, Darren W.; Siddiqui, Aleem; Busani, Tito

The exceptional material properties of Lithium Niobate (LiNbO3) make it an excellent material platform for a wide range of RF, MEMS, phononic and photonic applications; however, nano-micro scale device concepts require high fidelity processing of LN films. Here, we reported a highly optimized processing methodology that achieves a deep etch with nearly vertical and smooth sidewalls. We demonstrated that Ti/Al/Cr stack works perfectly as a hard mask material during long plasma dry etching, where periodically pausing the etching and chemical cleaning between cycles were leveraged to avoid thermal effects and byproduct redeposition. To improve mask quality on X- and Y-cut substrates, a H2-plasma treatment was implemented to relieve surface tension by modifying the top surface atoms. Structures with etch depths as deep as 3.4 µm were obtained in our process across a range of crystallographic orientations with a smooth sidewall and perfect verticality on several crystallographic facets.

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Sponsoring Organization:: USDOE

OSTI ID:: 1882440

Alternate ID(s):: OSTI ID: 2471764

Journal Information:: Nanomaterials, Journal Name: Nanomaterials Journal Issue: 16 Vol. 12; ISSN 2079-4991; ISSN NANOKO

Publisher:: MDPI AGCopyright Statement

Country of Publication:: Switzerland

Language:: English

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