Improvement of textured AlCu with Ta underlayer on LiNbO3 substrate

Hala Achahbar (1) , Florent Bernard (1) , Emilie Courjon (1) , Nicolas Martin (2) , Thomas Baron (2) , Sylvain Ballandras (3)

1 Frec|N|Sys - Frec|N|Sys
2 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)
3 Frec'n'sys SASU - Frec'n'sys SASU

Improving the lifetime of Surface Acoustic Wave filters requires reduction of electromigration effects. We report on the growth mechanism of AlCu2% film deposited by E-Beam Physical Vapor Deposition technique. State of the art shows that the introduction of an underlayer that alters the surface free energy can change a film's growth mode or improve the earliest stages of film formation. In this work, this will be achieved by using an ultra-thin (<5nm) Ta underlayer between the LiNbO3 substrate and the AlCu2% film. The effects of Ta underlayer on the microstructure of AlCu2%/LiNbO3 films is investigated. An increase in the surface energy of the LiNbO3 substrate is observed with the addition of 1.3nm thick Ta underlayer. Crystalline quality of AlCu2% thin film with a Ta underlayer is measured with XRD techniques. A post-deposition heat processing is also used to recrystallize the films. The AlCu2%/1.3Ta/LiNbO3 film annealed at 250°C improved the

Domaines: Acoustique [physics.class-ph]; Matériaux; Micro et nanotechnologies/Microélectronique; Autre

Hala Achahbar, Florent Bernard, Emilie Courjon, Nicolas Martin, Thomas Baron, et al.. Improvement of textured AlCu with Ta underlayer on LiNbO3 substrate. AIP Advances, 2022, 12 (10), pp.105121 - 105121-4. ⟨10.1063/5.0107058⟩. ⟨hal-03890951⟩