Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode

Abstract

The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1 0 0}-textured lead zirconate titanate (PZT) thin films was achieved on insulating MgO buffered, oxidized silicon substrates. IDEs were fabricated by lift-off techniques and cantilevers were formed by dicing. The deflection upon application of a sweeping voltage was measured as large signal response in parallel to the ferroelectric polarization (PV loop). Likewise, the small signal piezoelectric response was measured in parallel to the capacitance-voltage (CV) measurement. In this way, a complete picture of the ferroelectric–piezoelectric element was obtained. From the deflection, the in-plane piezoelectric stress in the PZT thin film was derived and, from this, the effective piezoelectric coefficients. For the latter, two types were defined: an engineering type corresponding to the average value along the IDE, which can directly be compared to coefficient of a parallel plate electrode (PPE) capacitor and a second one that approximately yields the idealized coefficient governing between the electrode fingers. The IDE structures were experimentally compared with PPE structures of identical film thickness. The resulting coefficients were of opposite sign, as expected. In spite of a much better polarization loop, the IDE device showed a lower average piezoelectric stress. The estimated peak value between the fingers was about the same as in the PPE device, corresponding to about 20 C m−2. Nevertheless, the result is very promising for cases where compressive piezoelectric stresses are required and for preventing cracking due to large piezoelectric tensile stresses in PPE systems.

Fully Transparent Friction‐Modulation Haptic Device Based on Piezoelectric Thin Film

“…The remanent polarization P r and coercive field E c of these transparent structures are 18 µC cm −2 and 35 kV cm −1 , respectively ( Figure a), which are comparable to state‐of‐the‐art PZT thin films in IDE configuration with metal electrodes. [ 41 ] The zero‐field permittivity ε′ value is 930 with losses of 0.05 and both exhibit a characteristic butterfly loop in their bias‐field‐dependencies (Figure 4b). The converse piezoelectric coefficient e 33,f , measured at large field in cantilever configuration in positive direction, [ 42,43 ] is 8.0 C m −2 .…”

Transparent Ferroelectric Capacitors on Glass

“…Finally, a clear ferroelectric behaviour is observed on the polarization-electric field (P-E) loop of PZT on glass with AZO electrodes, as shown in Figure 5 . The extracted value of remanent polarization P r is 15 μC/cm 2 , which is approximately half the value reported for 500-nm-thick (100) MPB PZT on Si with Pt IDE electrodes, but comparable to its counterpart in MIM geometry [ 17 ]. The calculated coercive field E c is 52 kV/cm.…”

Numerical Analysis and Optimization on Piezoelectric Properties of 0–3 Type Piezoelectric Cement-Based Materials with Interdigitated Electrodes

“…The amplitude of each strain response is different from the others. Therefore, during the preparation of the IEPCM, it is essential to ensure the positive and negative electrodes of the IEPCM are symmetric as far as possible, including the main branch corresponding to the positive and negative electrode branches [28].…”

“…Owing to interdigitated electrode (IE) technology, the polarization direction of the piezoelectric device with IEs is the same as the voltage-driving one, rendering a great improvement of the in-plane strain/stress-driving capacity, and obvious orthotropic features [22][23][24][25][26][27][28]. Zhang et al [22] documented that the 1-3 type PCM with IEs possessed a high piezoelectric constant and superior orthotropic features with different receiving sensitivities for the stress waves from orthogonal directions.…”

“…Liu et al [27] reported that the electrospinning of polyvinylidene fluoride (PVDF) and a CNT piezoelectric nanofiber array on IEs fabricated a flexible sensing device, and found that PVDF/CNT crystallization as spherical composite structures can enhance the piezoelectric properties of PVDF fibers and effectively convert the mechanical energies of low-frequency ambient vibrations and impacts into electrical signals. Chidambaram et al [28] studied the converse mode piezoelectric coefficient for PZT thin film with IEs, where the film with IEs showed a lower average piezoelectric stress than that with parallel-plate electrode, and effectively prevented cracking. However, to the best knowledge of the authors, there is no research work on the use of the IE technique in 0-3 type PCMs, and no exploration into the orthotropic and driving properties of the corresponding PCM.…”