Search

The e31 piezoelectric constant is presented for sputtered lead zirconate titanate thin films on silicon.

LMD-MS/MS analysis of several dermal microdissected amyloid deposits demonstrated high spectra for KRT5/14 heterodimers, along with the amyloid signature proteins. Spectra of other known amyloid proteins were not detected; notably, no spectra for light chain immunoglobulins were detected, ruling out AL amyloidosis. gl The Chinese family included three symptomatic members (II.8, II.9 and II.10), who complained of pruritic lesions, highly suggestive of lichen amyloidosis, over arms, legs and back. LC-MS/MS and immuno-electron subtyping combined with genetics show that OSMR mutations cause amyloid deposition of keratins 5/14 in familial primary localized cutaneous amyloidosis. [Extracted from the article]

The aim of this paper consists in the determination of the piezoelectric transverse coefficient d31 of PbZrxTi1-xO3 (PZT) thin films integrated in dedicated multilayer silicon-based micromembranes exhibiting an initial buckled profile. An analytical model specific to this configuration was built and used for the calculation of d31 starting with the static profiles of the microfabricated devices determined by means of a double-beam interferometer. The influence of dc voltage and buckling effects on the d31 piezoelectric coefficient at the microscale were investigated, and high values were obtained, from 30 to 75 pm/V, within a hysteresyslike cycle. These results demonstrated the good electrical behavior of PZT thin films at the microscale with a low influence of buckling effects and determined optimal operation conditions for high values of d31. [ABSTRACT FROM AUTHOR]

Ion-beam etching of sputtered Pb(Zrx,Ti1-x)O3 (PZT) thin films with x equal to 0.54 grown on Pt/TiOx/SiO2/Si substrates has been performed using pure Ar gas and a varying CHF3/Ar gas mixing ratio. The etch rate dependence on the process parameters (gas composition, current density, and acceleration voltage) has been investigated. PZT etch rate under 40% CHF3 in Ar can reach 100 nm/min with an acceleration voltage of 900 V and a current density of 0.7 mA/cm2 (in comparison to 35 nm/min in pure Ar). A selectivity ratio of 8 has been obtained between PZT and photoresist (1.3 in pure Ar). We have evaluated the PZT surface damage by contact mode atomic force microscopy. It appears that the roughness increases less under a gas mixture than under a pure argon beam, and that the preferential etching observed at the grain boundaries under a pure argon beam disappears when we increase the proportion of CHF3 in the gas mixture. For some etching parameters (current density, acceleration voltage, and gas mixing ratio), we have observed electrical damage. C(V) and hysteresis loops P(E) measurements before and after etching have demonstrated these degradations. We have noted a large decrease of the permittivity after the etching process, independently of the current density and the acceleration voltage. The ferroelectric damage was illustrated by a large increase of the average coercive field after etching in pure argon. The presence of CHF3 in the plasma partially reduces the damage. [ABSTRACT FROM AUTHOR]

Ferroelectric and dielectric characteristics of two types of SrBi2Nb2O9 thin films grown by pulsed laser deposition on Pt electrodes were determined: a randomly oriented SrBi2Nb2O9 film (sample A), grown on a so-called polycrystalline Pt/Ti/SiO2/Si (Pt/Si) and an epitaxial SrBi2Nb2O9 film (sample B) grown on a (110)Pt electrode epitaxially grown on (110)SrTiO3. Some h00 texturation was suggested by the strong intensity of the 200 diffraction peak in sample A whereas the epitaxial sample B presents a strongly (116) preferential orientation as evidenced by x-ray diffraction and electron channeling patterns. Remanent polarization (Pr) determined from the hysteresis loops recorded on several electrodes on samples A and B was typically in the range of 5–8.5 μC/cm2 for both samples. The Curie temperature (TC) determined from dielectric permittivity measurements versus temperature was 705 K, for both samples, which differ, in fact, in structural characteristics but not in composition. The Curie–Weiss temperature was found lower than TC, suggesting that the transition is of first order. The evolution of dielectric permittivity and dissipation factor was recorded versus frequency at different temperatures. At room temperature and low frequency (100 Hz), [variant_greek_epsilon]′ is close to 150 on both films. When increasing the frequency up to 1 MHz, the [variant_greek_epsilon]′ value decreased down to 137 for sample A and 129 for sample B. This evolution corresponds to a weak dispersion effect in relation with the high crystallization quality of the ferroelectric films. At the same time, dissipation factor tgδ increased from 1.5% to 1.8% and from 3.3% to 5.5% for samples A and B, respectively, when increasing the frequency from 100 Hz to 1 MHz. Further measurements at higher frequency were performed on the epitaxial film. As expected, dielectric permittivity decreased to about 100 when increasing the frequency to 0.5 GHz at room temperature, whereas tgδ increased up to about 9%. Decreasing the temperature down to 110 K contributes to decrease [variant_greek_epsilon]′ from 150 at room temperature to 122 at 110 K at 1 kHz and from 100 to 87 at 0.5 GHz. Simultaneously, tgδ decreases from 8.7% to 5.6% at 0.5 GHz. [ABSTRACT FROM AUTHOR]

Ion beam etching of sputtered Pb(Zr[sub x], Ti[sub 1-x])O[sub 3] (PZT) with x equal to 0.54 thin films grown on Pt/Ti/SiO[sub 2]/Si substrates has been performed using pure Ar gas. The etch rate dependence on the process parameters (current density, acceleration voltage, gas pressure) has been investigated. The PZT etch rate can reach 600 Å/min with acceleration voltage of 1000 V and current density of 1 mA/cm². Selectivity ratios between PZT and masks of various natures (photoresist, Pt, Ti) have been evaluated to determine a pertinent material for etching mask. According to our etching conditions, titanium seems to be the best candidate. We evaluated the PZT surface damage by contact mode atomic force microscopy. It appears that the roughness increases after ion bombardment, and that the grain boundary zone is preferentially etched. For some etching parameters, we also observed electrical damage. Carrying out C(V) and hysteresis loops P(E) measurements before and after etching have provided evidence of degradation. We noted a large decrease in permittivity after the etching process irrespective of the current density and acceleration voltage. Ferroelectric damage was illustrated by a large increase in the average coercive field. For each of the electrical properties under study, the same behavior has been observed after etching: the increase of damage was obtained as a function of the current density and acceleration voltage. The evolution of electrical properties when the PZT layer is protected by a metallic mask has also been studied. We observed very slight variations in the electrical properties. [ABSTRACT FROM AUTHOR]

A powerful analytical model for a multilayer circular plate, taking into account the tensile/compressive initial stress of materials, is developed. This model is modified for the study of the piezoelectric constant [d.sub.31] of PZT 54/46 thin film integrated on microscaled circular buckled membranes.

A brief report on the dielectric properties in a broad frequency range of two Ferroelectric Aurivillius-layered compounds SrBi2Nb2O9 thin films is presented. Dielectric permitivity and dissipation factor are determined at low temperature in view to integrate ferroelectric films in devices with metallic as well as superconducting materials, which requires cooling devices.