Aachen, Germany
Aachen, Germany

Time filter

Source Type

Kovacova V.,CEA Grenoble | Vaxelaire N.,CEA Grenoble | Le Rhun G.,CEA Grenoble | Gergaud P.,CEA Grenoble | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We observed that electric field induces phase transition from tetragonal to rhombohedral in polycrystalline morphotropic lead zirconate titanate (PZT) films, as reported in 2011 for bulk PZT. Moreover, we evidenced that this field-induced phase transition is strongly correlated with PZT film piezoelectric properties, that is to say the larger the phase transition, the larger the longitudinal piezoelectric coefficient d33,eff. Although d33,eff already reaches 130-150pm/V, our observation suggests that one could obtain larger d33,eff values, namely 250pm/V, by optimizing the field-induced phase transition thanks to composition fine tuning as close as possible to the morphotropic phase boundary. © 2014 American Physical Society.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: ICT-25-2015 | Award Amount: 4.00M | Year: 2015

Computer clock speeds have not increased since 2003, creating a challenge to invent a successor to CMOS technology able to resume performance improvement. The key requirements for a viable alternative are scalability to nanoscale dimensions following Moores Law and simultaneous reduction of line voltage in order to limit switching power. Achieving these two aims for both transistors and memory allows clock speed to again increase with dimensional scaling, a result that would have great impact across the IT industry. We propose to demonstrate an entirely new low-voltage, memory element that makes use of internal transduction in which a voltage state external to the device is converted to an internal acoustic signal that drives an insulator-metal transition. Modelling based on the properties of known materials at device dimensions on the 15 nm scale predicts that this mechanism enables device operation at voltages an order of magnitude lower than CMOS technology while achieving 10GHz operating speed; power is thus reduced two orders.

Hermes C.,Jülich Research Center | Hermes C.,Julich Aachen Research Alliance | Wimmer M.,Julich Aachen Research Alliance | Wimmer M.,RWTH Aachen | And 17 more authors.
IEEE Electron Device Letters | Year: 2011

In this letter, bipolar fast-pulse switching in TiO 2-based nanocrossbar devices was investigated. A dedicated measurement setup was used to measure the transient currents during 5-ns resistive switching. Transient peak currents for the set and reset processes were as high as 200 and 230 μA, respectively. The currents observed during fast-pulse switching are explained and simulated by Joule heating, which is needed for fast oxygen-vacancy movement. The measured transient currents enable a further optimization of resistive switches based on TiO 2. © 2011 IEEE.

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: ICT-02-2014 | Award Amount: 8.22M | Year: 2014

Smart-MEMPHIS project addresses the increasing demand for low-cost, energy-efficient autonomous systems by focusing on the main challenge for all smart devices - self-powering. The project aims to design, manufacture and test a miniaturized autonomous energy supply based on harvesting vibrational energy with piezo-MEMS energy harvesters. The project will integrate several multi-functional technologies and nanomaterials; lead-zirconate-titanate materials in MEMS-based multi-axis energy harvester, an ultra-low-power ASIC to manage the variations of the frequency and harvested power, a miniaturized carbon-nano material based energy storing supercapacitor, all heterogeneously integrated with new innovative flat panel packaging technologies for cost effective 3D integration verified through manufacturability reviews. The performance of the system will be demonstrated in two demanding applications: leadless bio-compatible cardiac pacemaker and wireless sensor networks (WSN) for structure health monitoring (SHM). For the pacemaker, a smart energy autonomous system will accelerate the paradigm shift from costly, burdensome surgical treatments to cost-effective and patient-friendly minimally invasive operations enabled by leadless pacemakers capable of harvesting energy from the heart beats. The key challenges for the energy harvesting arise from the extremely stringent reliability requirements, the low vibrational energies and frequencies and the small size required for a device implanted inside a heart. With the 2nd demonstrator the consortium consisting of multi-functional value chain will show a wider applicability for the technologies complementing the medical application. A WSN with acoustic sensor nodes will be demonstrated in SHM applications. SHM enables real-time monitoring of complex structures e.g. survey and detection of micro-cracks for example in composite aircraft wings, bridges or rails, or detection of corrosion or leakage in pipes solving.

Prume K.,AixACCT Systems GmbH | Wagner B.,Fraunhofer Institute for Silicon Technology | Ortner K.,Fraunhofer Institute for Surface Engineering and Thin Films | Jung T.,Fraunhofer Institute for Surface Engineering and Thin Films
Journal of Electroceramics | Year: 2010

Crack and void free polycrystalline Lead Zirconate Titanate (PZT) thin films in the range of 5 μm to 10 μm have been successfully deposited on silicon substrates using a novel high rate sputtering process. The sputtered PZT layers show a high dielectric constant εr between 1,000 and 1,800 with a moderate dissipation factor tan (δ) = 0,002 - 0,01 measured at f = 1 kHz, a distinct ferroelectric hysteresis loop with a remanent polarisation of 17 μC/cm2 and coercive field strength of 5.4 kV/mm. The piezoelectric coefficients d33,f = 80 pm/V are measured by using a Double Beam Laser Interferometer (DBLI). Based on this deposition process a membrane actuator mainly consisting of a SOI layer and a sputtered PZT thin film was prepared. The deflection of this membrane actuator depending on the driving voltage was measured with a white light interferometer and compared to the results of finite element analysis (FEA). With this approach a transverse piezoelectric coefficient of about e31 = -11.2 C/m2 was calculated, whereas all the other material parameters in the model were lent from PZT-5A. © 2010 Springer Science+Business Media, LLC.

Bastani Y.,Georgia Institute of Technology | Schmitz-Kempen T.,AixACCT Systems GmbH | Roelofs A.,AixACCT Systems GmbH | Bassiri-Gharb N.,Georgia Institute of Technology
Journal of Applied Physics | Year: 2011

Highly (100)-textured Pb(Zr0.53Ti0.47)O3 films (Lotgering factors ≥90%) with thicknesses ranging from 20 to 260 nm were grown on platinized Si substrates using sol-gel deposition. Ferroelectric hysteresis, low field dielectric permittivity, and nonlinear dielectric response as well as converse longitudinal piezoelectric response (d33,f) of the ultrathin films were studied at 1 kHz. The measurements revealed the existence of a critical film thickness, ∼50 nm, below which the extrinsic contributions to the dielectric response are almost completely suppressed. Piezoelectric response of the films also showed a significant (∼50%) drop at the same critical thickness. Due to the columnar microstructure of these films the critical dimension of the ferroelectric is represented by the thickness rather than the lateral grain size, where the latter is invariant across the samples. The critical thickness led also to a deviation of the thickness dependence of the dielectric permittivity from the in-series capacitors model frequently representing "interfacial dead layers." The critical size is attributed to significant reduction in domain wall population and/or mobility in films thinner than ∼50 nm. © 2011 American Institute of Physics.

Nguyen M.D.,MESA Institute for Nanotechnology | Nguyen M.D.,SolMateS BV | Nguyen M.D.,Hanoi University of Science and Technology | Dekkers M.,MESA Institute for Nanotechnology | And 7 more authors.
Applied Physics Letters | Year: 2011

A study on the effects of the residual strain in Pb(Zr 0.52Ti 0.48)O 3 (PZT) thin films on the ferroelectric and piezoelectric properties is presented. Epitaxial (001)-oriented PZT thin film capacitors are sandwiched between SrRuO 3 electrodes. The thin film stacks are grown on different substrate-buffer-layer combinations by pulsed laser deposition. Compressive or tensile strain caused by the difference in thermal expansion of the PZT film and substrate influences the ferroelectric and piezoelectric properties. All the PZT stacks show ferroelectric and piezoelectric behavior that is consistent with the theoretical model for strained thin films in the ferroelectric r-phase. We conclude that clamped (001) oriented Pb(Zr 0.52Ti 0.48)O 3 thin films strained by the substrate always show rotation of the polarization vector. © 2011 American Institute of Physics.

Sivaramakrishnan S.,Hewlett - Packard | Mardilovich P.,Hewlett - Packard | Mardilovich P.,Xaar Technology Ltd. | Mason A.,Oregon State University | And 3 more authors.
Applied Physics Letters | Year: 2013

The electrode size dependence of the effective large signal piezoelectric response coefficient (d33,f) of lead zirconate titanate (PZT) thin films is investigated by using double beam laser interferometer measurements and finite element modeling. The experimentally observed electrode size dependence is shown to arise from a contribution from the substrate. The intrinsic PZT contribution to d33,f is independent of electrode size and is equal to the theoretical value derived assuming a rigid substrate. The substrate contribution is strongly dependent on the relative size of the electrode with respect to the substrate thickness. For electrode sizes larger than the substrate thickness, the substrate contribution is positive and for electrode sizes smaller than the substrate thickness, the substrate contribution is negative. In the case of silicon substrates, if the electrode size is equal to the substrate thickness, the substrate contribution vanishes, and the measured value of d33,f is equal to the theoretical value under the rigid substrate assumption. © 2013 AIP Publishing LLC.

The application relates to a method for determining beam parameters of a charge carrier beam, a measuring device, and a charge carrier beam device. The charge carrier beam (4) from a charge carrier beam device (1) is guided, by means of a beam deflection unit (3), over a slit aperture arrangement which is provided in an aperture device (7) and which has one or more slit apertures (8). Measurement plane coordinates of the beam components that penetrate the slit aperture arrangement are determined. On the basis of the measurement plane coordinates, the aperture device automatically moves in such a way that a measuring aperture (9) arranged in the aperture device moves over a predefined measurement reference point. The beam parameter is measured by the measuring aperture. In a measuring device (5) suitable for carrying out said method, the slit aperture arrangement has at least two non-parallel slit aperture sections (12, 13, 15, 16) which can be part of a single continuous slit aperture.

Agency: Cordis | Branch: FP7 | Program: CP-TP | Phase: NMP-2008-3.5-1 | Award Amount: 5.14M | Year: 2010

This proposal will address high volume production of MEMS (Micro-Electro Mechanical Systems) with a piezoelectric thin film as active element (piezoMEMS). This technology can fulfil many of the requirements of sensors and actuators in tomorrows smart systems, as a result of the large displacements, high sensing functionality and high energy densities that can be obtained, compared to pure Si-MEMS. As a consequence, they are very attractive for industries like automotive, aerospace, medical, telecom and consumer electronics. Large European companies tend to buy devices like sensors for their products, rather than to develop processes and devices themselves. European SMEs are natural providers of such devices. However, since there are no automated facilities in Europe for volume production of piezoelectric microsystems, they are not able to commercialize piezoMEMS products. A combined effort by European research institutes, industry and SMEs can close this gap. The main vision of piezoVolume is to provide the means for high throughput, cost-effective and robust manufacturing of piezoelectric microsystems in Europe, where SMEs are both device developers and production technology providers. A set of procedures, guidelines and fabrication tools will be developed, enabling short time to market for new device concepts. piezoVolume will combine three leading research groups in Europe, which are already acting worldwide in the piezoMEMS scientific community, with highly relevant and skilled technological partners, to build a consortium that is able to develop a full production line for piezoMEMS in Europe for the first time. Readily available cost-effective wafer based batch processing of piezoMEMS will lower the threshold for industry acceptance and be the enabling technology to realise new products based on piezoMEMS.

Loading AixACCT Systems GmbH collaborators
Loading AixACCT Systems GmbH collaborators