Real-time studies of ferroelectric domain switching: a review

Abstract

Ferroelectric materials have been utilized in a broad range of electronic, optical, and electromechanical applications and hold the promise for the design of future high-density nonvolatile memories and multifunctional nano-devices. The applications of ferroelectric materials stem from the ability to switch polarized domains by applying an electric field, and therefore a fundamental understanding of the switching dynamics is critical for design of practical devices. In this review, we summarize the progress in the study of the microscopic process of ferroelectric domain switching using recently developed in situ transmission electron microscopy (TEM). We first briefly introduce the instrumentation, experimental procedures, imaging mechanisms, and analytical methods of the state-of-the-art in situ TEM techniques. The application of these techniques to studying a wide range of complex switching phenomena, including domain nucleation, domain wall motion, domain relaxation, domaindefect interaction, and the interplay between different types of domains, is demonstrated. The underlying physics of these dynamic processes are discussed.

Reversible transition between the polar and antipolar phases and its implications for wake-up and fatigue in HfO2-based ferroelectric thin film

“…Ensuring reliable and repeatable electrical performance from ferroelectric (FE) thin films and devices present a significant challenge for conventional FE materials such as perovskite-structured Pb(Zr,Ti)O 3 (PZT) to enable their use in FE memory devices 1 – 4 . Among the potential problems, fatigue, which is induced by defect (mainly oxygen vacancy (V O )) generation 5 and the accompanying FE domain pinning 6 , 7 that occurs during repeated electrical stimulation, is one of the most critical concerns 1 – 4 . While the discovery of ferroelectricity in doped HfO 2 thin films by Böske et al 8 in 2011 has again triggered enormous interest in FE memories 2 – 4 and several other novel applications 1 , 9 – 11 , these films are not exempt from serious fatigue concerns 2 , 3 .…”

Emergent properties at oxide interfaces controlled by ferroelectric polarization

“…Due to its versatility and fairly high spatial resolution (generally 5-10 nm), SPM has become the mainstream technology for researching the polar-gating effect 18,144,145 . S/TEM imaging can provide better spatial and temporal resolution to study atomicscale structures and intermediate stages of polarization switching 53,146 , but conventional imaging methods still cannot be used to study some ferroelectric phenomena, such as charge screening.…”

Homogeneous versus Inhomogeneous Polarization Switching in PZT Thin Films: Impact of the Structural Quality and Correlation to the Negative Capacitance Effect

“…Inhomogeneous switching is characterized by nucleation of domains with an opposite direction of polarization, followed by the growth of these domains until the polarization is fully switched and parallel with the applied electric field. There are many experimental and theoretical studies dedicated to this subject [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ]. However, one has to consider that, immediately after switching, a strong depolarization field is present in the ferroelectric sample.…”