Effects of potassium sodium niobate (KNN) thickness on biaxial non-resonant microelectromechanical systems (MEMS) mirror performance

<p>This work presents the results obtained with potassium sodium niobate (KNN) biaxial non-resonant microelectromechanical systems (MEMS) mirrors manufactured on a 200 mm silicon substrate. These MEMS mirrors feature various reflector dimensions for the squared shape, ranging from 0.5 <span...

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Bibliographic Details
Main Authors: L. Mollard, C. Dieppedale, A. Hamelin, R. Liechti, G. Le Rhun
Format: Article
Language:English
Published: Copernicus Publications 2025-02-01
Series:Journal of Sensors and Sensor Systems
Online Access:https://jsss.copernicus.org/articles/14/27/2025/jsss-14-27-2025.pdf
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Summary:<p>This work presents the results obtained with potassium sodium niobate (KNN) biaxial non-resonant microelectromechanical systems (MEMS) mirrors manufactured on a 200 mm silicon substrate. These MEMS mirrors feature various reflector dimensions for the squared shape, ranging from 0.5 <span class="inline-formula">×</span> 0.5 to 2 <span class="inline-formula">×</span> 2 mm<span class="inline-formula"><sup>2</sup></span>, and incorporate sputtered potassium sodium niobate ((K<span class="inline-formula"><sub>0.35</sub></span>Na<span class="inline-formula"><sub>0.65</sub></span>)NbO<span class="inline-formula"><sub>3</sub></span>) thin-film piezo-motors from Sumitomo Chemical, with thicknesses varying from 0.5 to 1.5 <span class="inline-formula">µ</span>m. A comparison of the mirror's performance and static deformation as a function of KNN thickness will be presented and discussed. The results obtained with these non-resonant mirrors, all fabricated using a collective 200 mm silicon manufacturing process, exhibit the following: (a) an arm deformation of 50 to 80 <span class="inline-formula">µ</span>m corresponding to an estimated tensile residual stress of approximately 120 MPa in the KNN layer, (b) the same level of performance for the 0.5 <span class="inline-formula">µ</span>m thick lead zirconate titanate (PZT) and KNN at 10 V, and (c) an optical angle up to 8.5° at 40 V for the 2 <span class="inline-formula">×</span> 2 mm<span class="inline-formula"><sup>2</sup></span> mirror design with 1.5 <span class="inline-formula">µ</span>m thick KNN. These results indicate that the MEMS mirrors fabricated with the KNN lead-free piezoelectric material offer state-of-the-art performances and open potential applications in a wide range of fields from light detection and ranging (lidar) systems to biomedical applications, thanks to the full biocompatibility of the KNN material.</p>
ISSN:2194-8771
2194-878X