First investigations on stoichiometric lithium niobate as piezoelectric substrate for high-temperature surface acoustic waves applications

Thierry Aubert (1) , Ninel Kokanyan (1) , Hassan Alhousseini (1) , Amine Taguett (2) , Florian Bartoli (1) , Jérémy Streque (3) , Hamid M'Jahed (3) , Pascal Boulet (3) , Omar Elmazria (3)

1 LMOPS - Laboratoire Matériaux Optiques, Photonique et Systèmes
2 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique
3 IJL - Institut Jean Lamour

Surface acoustic waves (SAW) technology is very promising to achieve high-temperature wireless sensors. However, there is currently a need for piezoelectric substrates with a high electromechanical coupling coefficient (K2 > 1%), able to operate under harsh environments, especially in the intermediate temperature range (300-600°C). None of the conventional SAW substrate can face this challenge. In particular congruent lithium niobate, whose K2 can exceed 5%, shows serious limitations from 300°C, mainly related to Li vacancies. Recent studies have demonstrated the potential of stoichiometric lithium niobate (s-LN) for high-temperature bulk acoustic waves applications. In this paper, we investigate this piezoelectric material for high-temperature SAW applications. In particular, we examine carefully the potential structural and chemical changes that s-LN surface can undergo during a high-temperature exposure. Finally, SAW resonators based on s-LN substrates are in situ characterized up to 600°C.

Mots clés: SAW sensors; stoichiometric lithium niobate; high-temperature; SAW

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Thierry Aubert, Ninel Kokanyan, Hassan Alhousseini, Amine Taguett, Florian Bartoli, et al.. First investigations on stoichiometric lithium niobate as piezoelectric substrate for high-temperature surface acoustic waves applications. IEEE Sensors 2017, IEEE, Oct 2017, Glasgow, United Kingdom. pp.576, ⟨10.1109/icsens.2017.8234068⟩. ⟨hal-01628825⟩