Influence of tensile vs. compressive stress on fatigue of lead zirconate titanate thin films

Authors

Aruchamy N., Schenk T., Kovacova V., Glinsek S., Defay E., Granzow T.

Reference

Journal of the European Ceramic Society, vol. 41, n° 14, pp. 6991-6999, 2021

Description

Novel applications of ferroelectric films require a variety of different substrates, which exert different mechanical stress on the film. This raises the question of reliability of differently stressed films. This work compares the cycling-induced fatigue of the polarization hysteresis of PZT films in different stress states. A tensile stress of +270 MPa, for PZT on fused silica glass, causes gradual degradation, while degradation sets in abruptly under compressive stress of −100 MPa, for PZT on sapphire. The main fatigue mechanism is domain wall pinning on charged defects. Reversible and irreversible domain wall processes in the small- and large-signal permittivity reveal that the fatigue behavior results from a variation of the ferroelectric domain structure. Films under tensile stress contain more 90° domain walls, which get pinned continuously on isolated defects. Compressive stress creates more 180° domain walls, which require formation of defect agglomerates during a certain threshold cycle number for pinning.

Link

doi:10.1016/j.jeurceramsoc.2021.07.010