Processing and Characterization of Piezoelectric Materials and Integration Into Microelectromechanical Systems

Abstract

Piezoelectric materials have been integrated with silicon microelectromechanical systems (MEMS) in both microsensor and microactuator applications. Thin-film materials selection and processing routes are reviewed. Some recent and emerging applications of piezoelectric MEMS are presented including acoustic emission microsensors, vibration monitors, molecular recognition biosensors, precision positioners, micropumps, and linear stepper motors.

Exclusive self-aligned β-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion

“…[1][2][3][4] These properties stem from its unique polymorphism which also gives rise to its extraordinary mechanical properties, high chemical resistance, good thermal stability and biocompatibility. [5] PVDF shows four significant crystalline phases α, β, δ and γ; [2,6] with the electroactive β-phase being utilized most frequently for the development of sensors, actuators [7,8] and microgenerators. [4,9,10] Owing to its importance, the formation of electroactive β crystalline phase has been intensively investigated through various routes, including melt casting, [15] solution deposition, [11] spin coating [12] and phase inversion.…”

Abnormal domain switching in Pb(Zr,Ti)O3 thin film capacitors

“…Ferroelectric thin films find applications in a broad range of devices including pyroelectric detectors, piezoelectric microsensors, and micromechanical pumps, 1 which require integration of solution-deposited films into a variety of material structures. One of the most important requirements for ferroelectric thin films in electronic devices is the symmetric switching between two opposite polarization states.…”

Nanomechanical characterization of cavity growth and rupture in hydrogen-implanted single-crystal BaTiO3

“…For a cavity radius larger than the critical radius, a cavity grows indefinitely or until the cavity ruptures or coalescence with another cavity intervenes. Because of the differences of elastic properties and surface energy, which are terms for volume and surface contributions on a cavity nucleation, Si has a smaller critical cavity radius ͑1-1.5 m at 500°C͒ than that for BaTiO 3 .…”

“…During the last several decades, thin-film ferroelectric materials have been widely used for applications in capacitors and gate dielectrics for nonvolatile random access memory ͑NVRAM͒ devices, actuators and microfluidic pumps in microelectromechanical system ͑MEMS͒, and electro-optical modulators. [1][2][3] In most of these cases, ferroelectric thin films have had a polycrystalline microstructure which may affect domain switching, charge retention, and time-dependent fatigue, as well as the magnitude of the macroscopic polarization and piezoelectric coefficients. Thus it has long been desirable, but not generally possible, to obtain truly single-crystal ferroelectric thin films on arbitrary substrates.…”