In this study, a self-sensitive piezoelectric cantilever with a new design for sensing is presented. Micro-cantilevers were actuated by a 120nm-thick Lead Zirconate Titanate Oxide (PZT) layer. Detection was done by measuring the resistance of a metallic gauge integrated on the surface of the micro-piezoelectric cantilevers. Some metallic gauges were embedded in a Wheatstone bridge to improve the measured resistance accuracy. Devices with direct resistance measurement were also realized. Gauge resistance responses were compared with an optical measurement by a White Light Interferometer. By biasing the PZT between −5V and 5V, cyclic deflection of the cantilever was detected with both optical and metallic gauge resistance systems. The two measurements fit. This self-sensitive piezoelectric cantilever can be used for fatigue test with packaged devices.

In this letter, we show that a longitudinal acoustic wave can be generated in X-cut LiNbO3 (LNO) thin films when a voltage bias is superimposed to the radio frequency signal. Although there is normally no coupling of this wave in X-cut LNO, its electrostrictive behavior combined with bias reaching 3.9 MV/cm induces an electromechanical coupling around 11%. This experiment was performed without acoustic isolation with the LNO substrate (high overtone bulk acoustic resonator configuration).

We report on the observation of elastic waves propagating in a two-dimensional phononic crystal composed of air holes drilled in an aluminum nitride membrane. The theoretical band structure indicates the existence of an acoustic band gap centered around 800 MHz with a relative bandwidth of 6.5% that is confirmed by gigahertz optical images of the surface displacement. Further electrical measurements and computation of the transmission reveal a much wider attenuation band that is explained by the deaf character of certain bands resulting from the orthogonality of their polarization with that of the source.

In this paper, we present the fabrication of micro cantilevers and the extraction of the transverse piezoelectric coefficient d31. Micro cantilevers were fabricated on SOI wafers by surface micromachining processes. By controlling the crystallization conditions, 2 μm-thick (100) and (111) highly oriented PZT films were obtained. Piezoelectric properties were compared according to two crystalline orientations. A model was adapted to extract d31 from deflection measurements. The interest of this d31 extraction is that the piezoelectric coefficient is performed in actual conditions of actuation.

Electrostrictive acoustic resonators have been widely investigated during the last 8 years. Despite their interesting dc-controlled electromechanical coupling and switchable properties, the main drawback remains their poor quality factor. Here we show that HBAR LiNbO3 single crystals can be useful to act as high quality factor switchable resonators thanks to their electrostrictive properties and to their intrinsic low acoustic losses. For a resonance frequency at 1.95GHz, HBAR Q reaches 9000. This outstanding behaviour could be of interest for RF applications.

In this paper a method to determine the piezoelectric constant of thin films is described. The characterization method is based on the dynamic behaviour of a heterogeneous cantilever. The electric behaviour of the bimorph is simplified in order to reach the lumped-element model which is common in the literature. Expressions of the motional elements have quite simple values. The characterization method has the advantage of being based on the resonance and anti-resonance frequencies and is therefore purely electrical. This characterization method includes the dielectric, fluidic and mechanical losses. An experimental protocol was written in order to measure each of these parameters (dielectric losses, quality factor and resonance-anti-resonance frequencies) used to evaluate the piezoelectric constant through an analytical formula which includes the losses. The dynamic characterization developed was compared to a classic static measurement of the piezoelectric constant. The two methods show similar results which validate the technique. The PZT piezoelectric constant has been evaluated on a thin film cantilever and shows a maximum absolute value of 5 C m(-2) for a 120 nm thin film.

Ba0.7Sr0.3TiO3 (BST) thin films 500 nm in thickness were prepared on technologically desirable Pt/TiO2/SiO2/Si(1 0 0) substrates by ion beam sputtering (IBS) and post-deposition annealing method. The effect of annealing temperature on the structural and dielectric properties of BST thin films was systematically investigated. A sharp transition in their tunable dielectric behaviours was observed in good agreement with the evolution of crystal structure from amorphous to crystalline phase. It was demonstrated that the perovskite phase could crystallize in BST films at a very low temperature, around 450 °C. The lowering of perovskite crystallization temperature in the BST films was explained in terms of the high energetic process nature of IBS technique. A high dielectric tunability of 42% at E (electric field intensity) = 500 kV/cm and a low loss tangent of 0.013 at zero bias were both obtained in the 450 °C-annealed film, thereby resulting in the highest figure-of-merit factor among all the different temperature annealed films. Moreover, the 450 °C-annealed film showed superior leakage current characteristics with a low leakage current density of about 10−4 A/cm2 at E = 800 kV/cm.

PbO – MgO – Nb 2 O 5 – TiO 2 (PMNT) pyrochlore thin films were prepared on Pt-coated silicon substrates by radio-frequency magnetron sputtering and postdeposition annealing method. Very interestingly, these pyrochlore-structured PMNT thin films exhibited ultralow dielectric losses, with a typical loss tangent as low as 0.001, and relatively high dielectric constants, typically εr∼170. It was found that the relative permittivity slightly but continuously increased upon cooling without any signature of a structural phase transition, displaying a quantum paraelectriclike behavior; meanwhile, the PMNT pyrochlore thin films did not show any noticeable dielectric dispersion in the real part of permittivity over a wide temperature range (77–400 K). Their dielectric responses could, however, be efficiently tuned by applying a dc electric field. A maximum applied bias field of 1 MV/cm resulted in a ∼20% tunability of the dielectric permittivity, giving rise to a fairly large coefficient of the dielectric nonlinearity, ∼2.5×109 J C−4 m−5. Moreover, the PMNT pyrochlore films exhibited superior electrical insulation properties with a relatively high breakdown field (Ebreakdown∼1.5 MV/cm) and a very low leakage current density of about 8.2×10−7 A/cm2 obtained at an electric field intensity as high as 500 kV/cm.

We present here a comparative study of sol-gel-derived 0.9Pb(Mg1/3Nb2/3)O(3)0.1PbTiO(3) (PMNT) thin films about 120 nm in thickness that were, respectively, deposited directly on a platinized Si substrate and on a Pb(Zr,Ti)O-3 (PZT)-buffered one, but were both annealed at 750 degrees C in ambient air. It was found that the PZT buffer layer plays an important role in the enhancement of crystallographic and electrical properties of PMNT thin films. The PMNT film grown on PZT-buffered platinized Si substrate showed a nearly pure perovskite structure, while the film without buffer layer contained a big amount of pyrochlore phase. Also, the PZT buffer layer changed the preferred orientation of PMNT thin films from (111) to mainly (110) orientation, and helped to improve the films' densification and microstructural evolution. Coherent with what was observed comparatively in structural characterization, enhanced dielectric and leakage current characteristics were observed in the film with buffer layer. For the PMNT film grown directly on Pt-coated Si substrate, the dielectric permittivity is as low as 570, whereas the value is enhanced to 1200 for the PMNT film with PZT buffer Layer. Moreover, the leakage current density of PMNT thin films is reduced remarkably, Toughly 4-5 orders of magnitude lower, by introducing the PZT buffer layer.

As layer transfer techniques have been notably improved these passed years, lithium niobate (LiNbO3) appears as a candidate for the next generation of ultra wide band RadioFrequency (RF) filters. Depending on the crystalline orientation, LiNbO3 can achieve electromechanical coupling factors Kt(2) more than 6 times larger than those of sputtered aluminium nitride films. In this paper, a process based on direct bonding, grinding, polishing and Deep Reactive Ion Etching (DRIE) is proposed to fabricate a single crystal LiNbO3 Film Bulk Acoustic Resonator (FBAR). From the fabricated test vehicles K-t(2) of 45% is measured confirming the values predicted by theoretical computations.

High permittivity Bi24Fe2O39 (BFO) thin films have been deposited on platinized silicon substrates by a low temperature process combining rf magnetron sputtering at room temperature and postdeposition annealing at 450 °C. A nearly pure tetragonal crystal structure with highly (201)-preferred orientation, determined by x-ray diffraction, was formed in the BFO thin film. The BFO film not only exhibits high dielectric permittivity (εr=113) and relatively low loss tangent (tan δ=0.012), but also shows a fairly small quadratic voltage coefficient of capacitance (α∼800 ppm/V2) and a small temperature coefficient of capacitance (αT∼790 ppm/°C). Moreover, the leakage current density, obeying the Fowler–Nordheim tunneling mechanism, remains at a reasonably low level with the increase in applied electric field (J∼10−6–10−4 A/cm2 under E=400 kV/cm). These attractive dielectric and electrical properties make the low temperature processed Bi24Fe2O39 thin film a promising candidate for high-k dielectric applications in silicon-based integrated circuits.

This paper presents different acoustic technologies available for innovative wireless designs. Solidly mounted BAW resonators, coupled resonator filters, Lamb wave devices and guided wave components are described. The advantages of these technologies are highlighted and their performances are compared. All these technologies can be used to design highly integrated wireless architectures.

The microelectronics industry is facing historical challenges to down scale CMOS devices through the demand for low voltage, low power, high performance and increased functionalities. The implementation of new materials and devices architectures will be necessary. HiK gate dielectric and metal gate are among the most strategic options to reduce power consumption and manage low supply voltage. Multigate architectures increase MOSFETs drivability, reduce power, and allow new memory devices opportunities for future applications. By introducing new materials(HiK, Ge, III-V, Carbon based materials like diamond, graphene and CNTs, molecules, ... ), and new functions such as sensing and actuation allowing to interface the outside world (M/NEMS, filters, Imagers, ... ), Si based CMOS will be scaled beyond the ITRS as the System-on-Chip/Wafer Platform. The Heterogeneous integration of these devices with CMOS will require new 3D and Packaging schemes leading to the increase of effective packing density, improving systems figures of merit.

In this paper, we propose a parametric study of aluminum nitride Lamb wave resonators. A Film Bulk Acoustic Resonator (FBAR) technology was used and integrated on a 200 mm silicon substrates process flow performed on a standard CMOS fabrication line. Experimental results show that frequency is defined mostly by the period of interdigitated electrodes, but also by a competing contribution of membrane width.

In this study, a new design for self-sensitive MEMS cantilevers is presented. Cantilevers were actuated with a 120 nm-thick Lead Zirconate Titanate (PZT) layer. Detection was done by using an integrated piezoresistive gauge in top and bottom electrodes. Some piezoresistive gauges were integrated in a Wheatstone bridge to improve the sensitivity. Devices with direct measurement gauge were also realized. Piezoresistive responses were compared with an optical measurement by a light interferometer. By poling the PZT between −5 V and 5 V, the ferroelectric cycle was observed with both optical and piezoresistive detections. The two measurements are fitting. This self-sensitive piezoelectric cantilever can be used for fatigue test with packaged devices. With this new design, piezoresistive gauge can be integrated without cost increase in piezoelectric devices because no technological steps are added for gauges realization.

High overtone bulk acoustic resonators (HBAR) have been realized using the Smart Cuttrade technology to transfer a thin X-cut LiNbO 3 layer onto an X-cut LiNbO 3 substrate. When the bonding of the two wafers is performed, an additional rotation along the normal axis is set to generate mode conversion between the two acoustic shear waves electromechanically coupled in X-cut LiNbO 3 . This enables excitation of only one of the two acoustic shear waves.