Ferroelectric and Ferroelastic Domain Related Formation and Influential Mechanisms of Vapor Deposited Piezoelectric Thin Films

Abstract

Compared to the bulk piezoelectric materials counterpart, piezoelectric thin films (PTFs) possess advantages of smaller size, lower power consumption, better sensitivity, and have broad application in advanced micro-electro-mechanical system (MEMS) devices. However, the performance of MEMS transducers and actuators are largely limited by PTFs piezoelectric properties. In this review, we focus on understanding structure-property relationship of vapor deposited PTFs, with emphasis on the effect of strain energy and electrostatic energy in thin films, especially, energy relaxation induced misfit dislocation and ferroelectric (FS) and ferroelastic (FC) domain formation mechanisms. We then discuss the microstructure of these domains and their influential mechanisms on piezoelectric properties, as well as the domain engineering strategies (i.e., internal and external stimuli). This review will motivate further experimental, theoretical, and simulation studies on FS and FC domain engineering in PTFs.

Pseudo‐Ferroelectric Domain‐Wall in Perovskite Ferroelectric Thin Films

“…Perovskite ferroelectric thin films with unique dielectric (𝜖) and piezoelectric (d) properties show great potential for use in microelectronic mechanical system as sensors and actuators because they exhibit the coupling effects between mechanical strain, [1][2][3] electric field and polarization. [4][5][6][7] The complexity of these coupling effects is attributed to various domains that are generated to accommodate the electrostatic and elastic energies induced DOI: 10.1002/adfm.202300330 by spontaneous polarization (P s ). [8][9][10] These domains are three-dimensional (3D) volumetric defects with oriented spontaneous polarization, and in perovskite ferroelectric thin films can be categorized as ferroelectric (FC) and ferroelastic (FS) domains, which dominate the out-of-plane and inplane polarization, respectively.…”