Etching properties of Na0.5K0.5NbO3 thin films by using inductively coupled CF4/Ar plasma

• We investigated the etching characteristics of the NKN thin films in CF4/Ar plasma using ICP system.
• The chemical reaction and byproduct of the etching process were determined by XPS analysis.
• We explained that the Na, K, and Nb form non-volatile byproducts on the surface of NKN thin films.

The etch process of the Na0.5K0.5NbO3 (NKN) thin film was performed in CF4/Ar plasma. We investigated the etch rate of the NKN thin films and the selectivity of NKN to SiO2 in an inductively coupled plasma. The maximum etch rate of the NKN thin films was 127.3 nm/min in CF4/Ar (= 4:16 sccm) plasma and the selectivity of NKN to SiO2 was 0.31. We analyzed the XPS narrow scan spectra for the reaction on the surface of the NKN thin films. From the XPS data analysis, we were assumed that the byproducts were generated on the surface of the NKN thin films during the etching process, but the physical sputtering process effectively removed the byproducts. We analyzed the morphologies of the surface of the NKN thin films from AFM measurement. The Ar concentration affects the surface morphology greatly.

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