Ferroelectric thin films for microsystems

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

An analytical model for 3D island growth in Atomic Layer Deposition (ALD) was derived from geometric and statistical principles. The model: (i) accounts for a random island distribution and spontaneous nucleation; (ii) expresses surface coverage, deposited mass, mass gain per cycle and surface roughness in closed-form equations; (iii) is expandable to alternative island shapes or processes beyond ALD, including variants of chemical vapor deposition. A Monte-Carlo simulation enabled visualization of the depo

Precise control over angstrom-scale pores in graphene remains a central challenge for exploiting its potential for gas separation. Most pore formation methods produce broad pore-size distributions with a long tail of nanometer-scale, nonselective pores. Here, we present a strategy based on simultaneous competitive growth and etching during chemical vapor deposition. By coupling CH 4 as a carbon precursor with CO 2 as a mild etchant, we establish a continuous kinetic regime in which pore expansion and shrink

The sputtering conditions for the deposition of the layers underneath active AlN films were analyzed for improving the quality of the active AlN, and the dependence of AlN deposition temperature on crystalline quality was investigated, where a reduced deposition temperature could reduce the process time and cost. Therefore wafers with a 25 nm bottom electrode on a 15 nm adhesion layer, a 100 nm piezoelectric AlN films and a 100 nm top electrode have been deposited using different metals (Mo, Pt and Al) as b

A new series connected 25 T hybrid magnet system is being set up by the Helmholtz Zentrum Berlin (HZB) for neutron scattering experiments. CRPP has designed and manufactured a pair of 20 kA current leads for the powering of the outer superconducting coils of the hybrid magnet system. In connection with the test of joints for JT60SA, the current leads were tested at ENEA at low voltage up to a current of 18 kA. The mass flow rates required to cool the current leads at different currents measured in the test

Pb(Zr, Ti)O-3 (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetr

The influence of internal stress anisotropy resulting from anisotropic loading in a roll-to-roll (R2R) process, and polymer substrate anisotropy on the crack onset strain (COS) of thin oxide coatings was analyzed. Experimental data obtained for R2R processed films were compared with data obtained using an isotropic sheet-to-sheet (S2S) process with the same anisotropic substrate. In the R2R case the COS was found to increase by 20% between the transverse direction and the machine direction. In the S2S case

Using first-principles calculations, we model the chemical vapor deposition (CVD) growth of carbon nanotubes (CNT) on nanoparticles of late-transition (Ni, Pd, Pt) and coinage (Cu, Ag, Au) metals. The process is analyzed in terms of the binding of mono- and diatomic carbon species, their diffusion pathways, and the stability of the growing CNT. We find that the diffusion pathways can be controlled by the choice of the catalyst and the carbon precursor. Binding of the CNT through armchair edges is more favor

A review. Boron-doped diamond (BDD) thin films were grown on various substrates by chem. vapor deposition to achieve a new electrode material that possesses unique electrochem. properties. This electrodes could generate hydroxyl radicals under polarization at high anode potentials, and these hydroxyl radicals could be spin-trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The generated hydroxyl radicals had low electrochem. activity and high chem. reactivity, and these properties were attributed to the we

The results of structural and electrical characterizations of SrTiO3 thin films deposited onto MgO and LaAlO3 substrates by pulsed laser deposition technique are presented. The influence of substrate and annealing procedure on the crystalline structure and dielectric properties of these ferroelectric thin films are investigated. The obtained experimental data are analyzed in terms of the Landau theory taking into account the room-temperature lattice mismatch of the ferroelectric and substrates as well as th

A review of the properties of ferroelectric materials that are relevant to microwave tunable devices is presented: we discuss the theory of dielectric response of tunable bulk materials and thin films; the experimental results from the literature and from own work are reviewed; the correspondence between the theoretical results and the measured properties of tunable materials is critically analyzed; nominally pure, real (defected), and composite bulk materials and thin films are addressed. In addition, tech

The Laboratory of Electrical Machines of the Swiss Federal Institute of Technology (Lausanne) has developed a software (TLSim) for the simulation of electrical urban transportation systems. This program can simulate the behaviour of the power supply network (current and voltage level at any point of the topology) comprising uni- and bi- directionnal sub-stations. In the network the vehicules (trolleybus) may run along any defined path through different electrical supply sectors. Several models of trolleybus

The E-J power law as electric characterization of the HTS material in Finite Element computations has shown good agreement with measurements of field-dependent crtical current density and losses due to transport current. We use this technique to investigate the loss caused by Ac transport current in self-field and in applied AC magnetic field in both elliptical monocore and multicore tapes, where the current is generated by means of a voltage source. The current density is first kept constant and then varie

B-doped diamond films were deposited by large-area hot filament chem. vapor deposition (HFCVD) on Si and different industrial electrode materials, such as Ti, Zr, Nb, Ta, W, and graphite, with areas up to 50 * 60 cm2. B-doping levels ranging from 50 to several thousand ppm were realized using trimethylborate. These electrodes are characterized in terms of their material and electrochem. properties by SEM, Raman spectroscopy, secondary ion mass spectrometry (SIMS), and cyclic voltammetry. Oxidn. of org. comp

We have investigated the deposition at zero impact kinetic energy of the Ag atom and clusters (Ag/sub 7/,Ag/sub 19/) on the (100) and (111) surfaces of Pd by molecular dynamics simulations performed within the embedded atom-method scheme. Our results elucidate the role played by the adsorption energy in determining the final morphology of the cluster/substrate system when ideal nondestructive deposition conditions are implemented. While implantation of the atom is not observed, we find a finite probability

It is shown that at weak alternating stress the relationship between the piezoelectrically induced charge and applied stress in ferroelectric ceramics has the same form as the Rayleigh law for magnetization versus magnetic field in ferromagnetic materials. Applicability of the Rayleigh law to the piezoelectric effect is demonstrated in detail for lead zirconate titanate (PZT) ceramics. Experimental results indicate that the dominant mechanism responsible for piezoelectric hysteresis and the dependence of th

We study the deposition and the very first steps of nucleation and growth of Ag on Pd(100) with thermal energy atom scattering. This technique is a very sensitive and nonperturbing probe to surface point defects, which permits an in situ and in-time monitoring of the deposition. The intention of this paper is to give a detailed description of the approach used in our work. The form of the specularly reflected helium signal as a function of coverage and surface temperature is compared to a theoretical curve,

The low energy part of proton induced SBD spectra have higher number of counts than expected from p+Si reactions. This is the case for all proton incident angles but the effect increases when approaching grazing angles. The effect is shown to be mainly due to direct ionization (including straggling) by the protons. The energy deposition due to this process is first calculated using the chord length distribution model which assumes a constant LET value for the protons. This model can explain the main feature

The processing, mechanical analysis, and performance of functionally graded materials containing a metallic phase is reviewed in two parts. This first part focuses on processing, and distinguishes two principal process classes in graded materials production. The first class, termed' constructive processes', produces gradients by stacking selectively two or more starting materials, allowing full and potentially automated control of compositional gradients. The second class is termed 'transport based processe

The fluid equations for an electron beam are used to calculate the equilibrium velocity and density profiles, limiting current and space-charge wave properties of an annular beam undergoing magnetic compression in a gyrotron beam tunnel. Both non-relativistic and relativistic equations are derived. The beam tunnel may have a conventional smooth wall or an absorbing dielectric-loaded wall. Small values of magnetic compression are seen to have large effect on the profiles and the current limit of a given tunn

The selectivity of Cu deposition from bis(hexafluoroacetylacetonato)Cu(II) on SiO2 patterned with a Pt seeding layer was studied as a function of the reagent gas mixt. On Pt, the Cu film growth rate increases with the amt. of H2O vapor in the gas flow, and is independent of the chem. nature of the carrier gas used (H2 or He). The selectivity of the Cu deposition is significantly improved when using He rather than H2 as carrier gas, esp. at high H2O vapor concns. where rapid film growth can be obtained.

Ferroelectric thin films for microsystems

Chat with Graph Search

Analytical model for island growth mode in thin film deposition

Bidirectional Size Control for Angstrom-Scale Graphene Pores by Competitive Growth and Etching

Optimization of Sputter Deposition Process for Piezoelectric AlN Ultra-Thin Films

Results of the test of a pair of 20 kA HTS current leads

Dielectric and acoustical high frequency characterisation of PZT thin films

Influences of roll-to-roll process and polymer substrate anisotropies on the tensile failure of thin oxide films

Effect of metal elements in catalytic growth of carbon nanotubes

Application of synthetic boron-doped diamond electrodes in electrooxidation processes

Shift of phase transition temperature in strontium titanate thin films

Ferroelectric materials for microwave tunable applications

TLSim: A software for Electrical Public Transportation Systems

Losses in HTS Tapes due to AC External Magnetic Field and AC Transport Current

Properties of diamond electrodes for wastewater treatment

Deposition of metallic clusters on a metallic surface at zero initial kinetic energy: evidence for implantation and site exchanges

Stress and frequency dependence of the direct piezoelectric effect in ferroelectric ceramics

Surface mobility of Ag on Pd(100) measured by specular helium scattering

Direct processes in the energy deposition of protons in silicon

Functionally graded metals and metal-ceramic composites .1. Processing

Equilibrium and Space-Charge Wave Analysis of Electron-Beams in Conducting and Absorbing Gyrotron Beam Tunnels

Low-pressure chemical vapor deposition of copper: dependence of the selectivity on the water vapor added to a hydrogen or helium carrier gas