Novel 3D PZT thin film structure for micromechanics

In this work, fabrication and properties of 3-dimensional structures coated with piezoelectric Pb(Zr,Ti)O3 (PZT) thin films have been studied in order to improve the piezoelectric coupling into the third dimension. Calotte layers have been chosen as demonstration devices. The base diameters range from 40 to 120μm, the height varies between 10 to 40μm. A dynamic, in-situ co-sputtering process allowing for in-situ growth was applied. Micromoulds were formed by wet etching in silicon. The etchant was a HNA solution (HF, HNO3, CH3COOH) on a silicon dioxide mask. Calottes were obtained with the desired geometry and smooth surface state after few minutes etching time, and the use of chemical mechanical polishing (CMP). After deposition of the PZT membrane, deep silicon dry etching was then used to liberate the calotte layer. The dielectric constant and loss tangent of the calotte capacitors amounted to 830 and 5%, respectively (10kHz). The fundamental resonance frequencies varied between 2.5 and 16.5MHz, and were found to be inversely proportional to the base area of the calotte, the proportionality factor being 0.08Hz m

Domain and lattice contributions to dielectric and piezoelectric properties of Pb(Zrx, Ti1−x)O3 thin films as a function of composition

In situ reactively sputter deposited, 300-nm-thick Pb(Zrx, Ti1−x)O3 thin films were investigated as a function of composition, texture, and different electrodes (Pt,RuO2).X-ray diffraction analysis, ferroelectric, dielectric, and piezoelectric measurements were carried out. While for dielectric properties bulklike contributions from lattice as well as from domains are observed, domain wall contributions to piezoelectric properties are very much reduced in the morphotropic phase boundary (MPB) region. Permittivity and d33 do not peak at the same composition; the MPB region is broadened up and generally shifted to the tetragonal sid

Piezoelectric materials parameters for piezoelectric thin films in GHz applications

Piezoelectric thin films have existing and promising new applications in microwave filter technologies. The final performance depends on many parameters, and very specifically on the materials properties of each involved material. In this article, materials and properties for thin-film bulk acoustic wave resonators are discussed on some selected issues: the piezoelectric coefficients and acoustic losses of AlN, the relation of the first one with microstructural parameters, the inclusion of parasitic elements, and the merits of and problems with ferroelectric material

Perfil logístico de Colombia

El presente documento ofrece un estudio del perfil logístico de Colombia con la finalidad de dar a conocer el estado de arte de las ciudades, puertos e infraestructura principal para facilitar la toma de decisiones de los empresarios. Para el desarrollo de este trabajo se determinaron a partir de un análisis competitivo del país; las principales ciudades y puertos; logrando establecer un inventario de maquinaria y equipo e infraestructura logística; enmarcados en retos ya establecidos en las políticas públicas.This document provides a profile study logistics Colombia in order to present the state of art of the cities, ports and infrastructure in facilitating the decision making of managers. For the development of this work were determined from a competitive analysis of the country's major cities and ports, making an inventory of machinery and equipment and logistics infrastructure; framed challenges established in public policy

A finite element based formulation for sensitivity studies of piezoelectric systems

Sensitivity Analysis is a branch of numerical analysis which aims to quantify the affects that variability in the parameters of a numerical model have on the model output. A finite element based sensitivity analysis formulation for piezoelectric media is developed here and implemented to simulate the operational and sensitivity characteristics of a piezoelectric based distributed mode actuator (DMA). The work acts as a starting point for robustness analysis in the DMA technology

Conducting barrier electrodes for direct contact of PZT thin films on tungsten

Two W protection schemes for direct-contact bottom electrodes for PZT thin films, namely RuO2/Cr and RuO2/Ru, were compared with respect to protective performance and contact resistance up to 800 degrees C annealing temperature in oxygen. Cr clearly offers better protection for W than Ru-based schemes by forming a passivating Cr2O3 layer. No Cr is detected on the RuO2 surface, even after annealing at 800 degrees C, due to its entrapment by RuO2 by oxidoreduction. However, the formation of a continuous Cr2O3 film at the RuO2/Cr interface gives rise to an increased contact resistance above 650 degrees C. RuO2/Ru does not show any measurable contact resistance on W, but fails above 600 degrees C

Taking piezoelectric microsystems from the laboratory to production

Reliable integration of piezoelectric thin films into silicon-based microsystems on an industrial scale is a key enabling technology for a wide range of future products. However, current knowledge in the field is mostly limited to the conditions and scale of academic laboratories. Thus, knowledge on performance, reliability and reproducibility of the films and methods at industrial level is scarce. The present study intends to contribute to the development of reliable technology for integration of piezoelectric thin films into MEMS on an industrial scale. A test wafer design that contained more than 500 multimorph cantilevers, bridges and membranes in the size range between 50 and 1,500 μm was developed. The active piezoelectric material was a ∼2 μm thin film of lead zirconate titanate (PZT) deposited by a state-of-the-art chemical solution deposition (CSD) procedure. Automated measurements of C(V) and dielectric dissipation factor at 1 kHz were made on more than 200 devices at various locations across the wafer surface. The obtained standard deviations were 4.5 and 11% for the permittivity and dissipation factor, respectively. Values for the transverse piezoelectric charge coefficient, e 31,f, of up to −15.1 C/m2 were observed. Fatigue tests with a 5 kHz signal applied to a typical cantilever at ± 25 V led to less than 10% reduction of the remanent polarisation after 2 × 107 bipolar cycles. Cantilever out-of-plane deflection at zero field measured after poling was less than 1.1% for a typical 800 μm cantilever