Investigation on various insulator layers for MFIS capacitors

Abstract

Effects of insulator layers of Metal(Au)/Ferroelectrics(PZT)/Insulator/Si (MFIS) structure capacitors are investigated for non-destructive type non-volatile memory device applications. Various high dielectric oxide layers such as Al₂O₃, Ta₂O₅, TiO₂ and ZrO₂ were fabricated by reactive sputtering as insulating layers. The oxide insulators give significant impacts on the morphologies of PZT layer and the properties of capacitors. It is noted that the oxide layers with small thermal expansions (<6x10^–6/°C) coefficient caused cracks on PZT films during PZT crystallization annealing. The effects of insulators as a diffusion barrier are also comparatively studied using Auger electron spectroscopy. In addition, the characteristics of high dielectric solid solution, such as titanium oxide-zirconium oxide, are also studied.     

Improved CD control and line edge roughness in E-beam lithography through combining proximity effect correction with gray scale techniques

A proximity effect correction (PEC) technique for E-beam lithography is presented which overcomes hardware limitations of many older E-beam writers regarding the number of physical dose classes by a unique combination of gray scale techniques with PEC using the Layout BEAMER software. The benefit is not only an improvement in critical dimension control, but also an improvement in line edge roughness (LER). Compared to standard PEC techniques the percentage line width deviation has been dramatically reduced by more than a factor of three.     

The characteristics of the size-controlled Pb-based glass powders with spherical shape

The spherical shape Pb-based glass powders with the mean sizes between 370 and 990 nm were prepared by spray pyrolysis. The transparencies of the dielectric layers were slightly affected by the mean sizes of the Pb-based glass powders at the firing temperature of 580 °C. However, the transparencies of the dielectric layers fired at low temperatures between 460 and 520 °C were strongly affected by the mean sizes of the Pb-based glass powders. The transparencies of the dielectric layers formed from the glass powders with the mean size of 370 nm changed from 96.1 to 68.2% when the firing temperatures of the dielectric layers were changed from 580 to 440 °C. On the other hand, the transparencies of the dielectric layers formed from the glass powders with the mean size of 990 nm changed from 95.2 to 16.4% at the same firing temperatures ranges. The Pb-based glass powders with fine size melted at low firing temperatures. Therefore, dielectric layers formed from the Pb-based glass powders with fine size had dense inner structure and high transparencies even at low firing temperatures.     

Mathematical modeling for the estimation of lipase activity by agar diffusion method

A mathematical model was developed to estimate the lipase activities from the experimentally obtained physical dimension of halo, formed by a diffusing lipase through agar media. A diffusion equation based upon the mass balance was derived in cylindrical coordinates, the integration of which was carried out by using finite difference method. A regressional analysis of the experimental data using the proposed model has brought the values for the hindered diffusivity of lipase through agar media and the minimum effective lipase concentration of 0.817 × 10⁻⁶ cm² /s and 2.86 unit/ cm³, respectively. The procedures, delineated in this work are considered to be useful for the quantitative analysis of haloforming enzymes at predetermined standard conditions.     

UV written waveguides using crosslinkable PMMA-based copolymers

Crosslinkable copolymers poly(methylmethacrylate/2-methacryloylethylmethacrylate) (P(MMA/MAOEMA)) were developed for waveguide applications. P(MMA/MAOEMA) can crosslink under either UV exposure or heating. The UV-induced refractive index change in unreacted P(MMA/MAOEMA) is found to depend on the fluence. UV exposure of thermally crosslinked P(MMA/MAOEMA) can induce further structure change and thus index change, and therefore, was found to be useful for creating the core layers in optical waveguides. The photosensitivity of the thermally crosslinked polymers is sufficient for the fabrication of low loss (<1 dB/cm) channel waveguides in the thermally crosslinked copolymer system.     

Effect of heat treatment on photoluminescence behavior of BaMgAl10O17:Eu phosphors

The blue phosphor of BaMgAl₁₀O₁₇:Eu²⁺ (BAM) powders were prepared by solid-state reaction. The thermal degradation of BAM phosphor significantly reduces the intensity of the blue emission. BAM is reduced by an amount of 50% after heating at around 800 °C for 1 h. Photoluminescence (PL) excitation and emission spectra showed that the blue emission of 450 nm peak decreased with increasing annealing temperature. The ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transition of Eu³⁺ were observed at 590 and 615 nm emission lines over 1100 °C. Electron paramagnetic resonance (EPR) spectrum also detected two signals of Eu²⁺, corresponding to g=3.7156(9) for 88 mT, and g=2.9507(9) for 133 mT. X-ray absorption near edge structure (XANES) spectrum decreased the intensity of Eu²⁺ for 6977 eV with increasing annealing temperature, while high-energy peak of Eu³⁺ for 6984 eV was increased. The combined use of X-ray and neutron data by the Rietveld refinement appears to support that the secondary phase of EuMgAl₁₁O₁₉ magnetoplumbite structure in BAM may be formed by heat treatment.     

Vibration analysis of a 3-dimensional piping system conveying fluid by wave approach

Vibration analysis of a piping system conveying fluid is investigated by employing the wave approach. In this paper, the inviscid fluid-dynamic forces acting on a pipe due to internal fluid flow are approximated by the plug-flow model with the slender-body theory. The straight pipe elements conveying fluid are formulated using a dynamic stiffness matrix in the frequency domain. The curved pipe sections are treated with a single curved pipe element utilizing the mixed methodology of the dynamic stiffness method and the transfer matrix method. The present approach is applied to the frequency response analysis of the 3-dimensional piping system conveying fluid which is composed of straight and curved pipe sections and is compared to the results from the finite-element formulations.     

Fabrication of submicron-sized copper structures on pre-patterned self-assembled monolayer and Langmuir-Blodgett films

The fabrication of a metal microstructure on pre-patterned organic templates, prepared using SAM and LB techniques is described. The OTS derivatized substrate was oxidized by AFM anodic oxidation at the threshold voltage. Site-selective copper structure was then fabricated on the locally modified monolayer based on pre-designed patterns. The sequential adsorption-reduction of copper ion was carried out, leading to improved metal coverage and a reduction in defects.     

Bayesian object extraction from uncalibrated image pairs

This paper proposes a region-based algorithm for the extraction of foreground objects in uncalibrated images or video sequences. At the initialization step, a pair of images are overly segmented based on color and texture. Then, several dominant transforms that represent the relationship between two images are found, and each pixel is transformed by these transformations. By considering transform parameters and using the proposed area-ratio test, each pixel is assigned to a background or an object. We consider the resulting binary image as a binary random field, from which the likelihood of being foreground is computed for each initial segment. Using the likelihood model for each segment and the a priori assumption on the smoothness of labels, Bayesian approach is applied to label the segments. Experiments on various images and videos show promising results that the objects are clearly extracted.