Conventional Barrier Research Articles

偏光パララックスバリア方式多視点立体ディスプレイの試作

A display system requiring no special glasses is useful for 3D images. The parallax barrier display system has superior characteristics, such as having a planar screen and a thin panel. However, a conventional multi-view parallax barrier display system has disadvantages such as having images with divided horizontal resolution. We described a newly developed four-view display with a parallax polarizer barrier. This 3D display could avoid problems of conventional systems and viewing positions of parallax images could be arbitrarily arranged.

Integration of Novel Capacitor Structure for High Density FeRAM With Barrier Metal TiAlN and (Bi,La)4Ti3O12

16M 1T1C ferroelectric random access memory was successfully integrated by newly proposed scheme named Recessed Open Barrier (ROB) structure with planar Pt/BLT/Pt/IrOx/Ir stacked capacitor. In conventional barrier metal scheme which bottom electrode was stacked, oxygen diffused through the bottom electrode interface formed during MTP structure integration, and oxidized the edge of barrier metal resulting compressive stress. The failure was accelerated by free oxygen diffusion as the stress built up to make the bottom electrode pop-up. In this paper, the barrier metal TiAlN was recessed and refilled by ALD Al2O3 after bottom electrode patterning. By this novel structure, oxidation resistance was greatly improved, because oxygen diffusion path to BM was much longer than conventional scheme. The contact resistance of storage node was below 10 kΩ/plug after all the thermal budget relevant to BLT capacitor.

Scalable barrier synchronisation for large-scale shared-memory multiprocessors

Barrier synchronisation is very important in scalable multiprocessors. As network latency rapidly approaches thousands of processor cycles and multiprocessors systems become larger and larger, conventional barrier techniques are failing to keep up with the increasing demand for efficient synchronisation. In this paper, we present a memory controller-based operation that optimises the barrier function of an OpenMP library. The proposed mechanism allows atomic operations on the barrier variable to be executed on the home memory controller and the home memory controller to send fine-grained updates to waiting processors when a barrier variable reaches certain values. On a cycle-accurate execution-driven simulator, experiment results show that the proposed barrier implementation outperforms a conventional LL/SC (Load-Linked/ Store-Conditional) version by 20.8X, a conventional processor-side atomic instruction version by 15.5X, and an active messages version by 13.4X. To the best of our knowledge, the proposed barrier achieves better performance than all other existing non-hardwired implementations, and with an improved programming interface.

Capacity-coupled multidischarge for atmospheric plasma production

We propose a method of plasma production by capacity-coupled multidischarge (CCMD) at atmospheric pressure. The discharge gaps in the CCMD consist of a common electrode and a number of compact electrodes (CCE) which are directly coupled with small capacitors for quenching the discharge. A simple CCE structure is provided by a cylindrical capacitor, the inner conductor of which is used as a gap electrode. A short pulse discharge is observed to appear homogeneously at each CCE. A charge transfer for the single-pulsed discharge is 10–100 times as large as that of the conventional dielectric barrier discharge. A high efficiency of ozone production has been confirmed in the CCMD using O2 gas. A device configuration of the CCMD is quite flexible with respect to its geometrical shape and size. The CCMD could be used to produce plasmas for various kinds of industrial applications at atmospheric pressure.

경계요소법을 이용한 간섭형 방음벽의 설계

This paper investigates the insertion loss of nosie barrier with a interference device, The efficiency of the conventional interference-type noise barrier depends on specific frequency, Thus this study is performed to improve the efficiency of the nosie barrierin the range of broadband frequency. by changing the shape of interference device and adding the channel with various depths, The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

Step-edge versus interior barriers to atom incorporation at lattice steps

Observations of the spatial distribution of individual atoms over close-packed (111) clusters of the fcc metals platinum as well as iridium reveal that atoms preferentially populate the inner region. The inner region is separated by an energy barrier from the step edge, leaving empty of adatoms a ring approximately three nearest-neighbor distances wide. The effect of such an interior energy barrier upon the lifetime to atom incorporation into steps is explored for one- as well as two-dimensional clusters. Interior barriers are found to increase the lifetime to incorporation much more than the conventional step-edge barrier, and may significantly affect the morphology of growing surfaces.

Measurements of the thermal gradient over EB-PVD thermal barrier coatings

Conventional two-layered structure thermal barrier coatings (TBCs), graded thermal barrier coatings (GTBCs) and graded thermal barrier coatings with micropores were prepared onto superalloy DZ22 tube by electron beam physical vapor deposition (EB-PVD). Thermal gradient of the TBCs was evaluated by embedding two thermal couples in the surfaces of the tube and the top coat at different surrounding temperatures with and without cooling gas flowing through the tube. The results showed that higher thermal gradient could be achieved for the GTBCs with micropores compared to the two-layered structure TBCs and GTBCs. However, after the samples were heated at 1050°C, the thermal gradient for the GTBCs with or without micropores decreased with the increase of heating time. On the other hand, the thermal gradient for the TBCs increased with the increase of heating time. Cross-section observations by scanning electron microscopy showed that the change in microstructure was the main reason for the change of the thermal gradient.

Reduced temperature and bias-voltage dependence of the magnetoresistance in magnetic tunnel junctions with Hf-inserted Al2O3 barrier

A modified tunnel barrier structure for the magnetic tunnel junction (MTJ) was fabricated by inserting a Hf layer in the middle of the Al2O3 tunnel barrier. MTJs with the Hf-inserted barrier show a higher tunnel mangnetoresistance (TMR) ratio and weaker temperature and bias-voltage dependence of TMR compared to the MTJs with a conventional Al2O3 barrier. The enhancement of the TMR ratio and the reduction of the temperature and bias-voltage dependence were attributed to the reduction of defects in the barrier.

이중 절연층 공정에서 상부절연층의 산화시간에 따른 터널자기저항 특성연구

We fabricated TMR devices which have doubly oxidized tunnel barrier using plasma oxidation method to form homogeneously oxidized AlO tunnel barrier. We sputtered 10 -bottom Al layer and oxidized it with oxidation time of 10 sec. Subsequent sputtering of 13 -Al was performed and the metallic layer was oxidized for 50, 80, and 120 sec., respectively. The electrical resistance changed from 500 Ω to 2000 Ω with increase of oxidation time, while variation of MR ratio was little spreading 27∼31 % which is larger than that of TMR device of ordinary single tunnel barrier. We calculated effective barrier height and width by measuring I-V curves, from which we found the barrier height was 1.3∼1.8 eV sufficient for tunnel barrier, and the barrier width () was smaller than physical thickness. Our results may be caused by insufficient oxidation of Al precursor into A1O. However, doubly oxidized tunnel barriers were superior to conventional single tunnel barrier in uniformity and density. Our results imply that we were able to improve MR ratio and tune resistance by employing doubly oxidized tunnel barrier process.

Reduction of Off-State Leakage Current in Schottky Barrier Thin-Film Transistors (SBTFT) by a Field-Induced Drain

Detailed conduction mechanisms in a conventional Schottky barrier thin-film transistor (SBTFT) and a recently proposed novel SBTFT with field-induced drain (FID) extension have been studied. The new SBTFT device with FID extension shows excellent ambipolar performance with effective suppression of gate-induced drain leakage (GIDL)-like off-state leakage that plagues conventional SBTFT devices. By characterizing the activation energy of the conduction process in the off-state for conventional SBTFT devices, it is suggested that field emission of carriers from the drain junction is the major conduction mechanism. While for the FID SBTFT devices, owing to the effect of Fermi level pinning in the FID region, thermionic emission rather than field emission becomes the dominant conduction mechanism, resulting in the effective suppression of the undesirable GIDL-like leakage current.

Tunnel Magnetoresistance with Plasma Oxidation Time in Double Oxidized Barrier Process

We fabricated TMR devices which have double oxidized tunnel barrier using plasma oxidation method to form homogeneously oxidized AlO tunnel barrier. We sputtered 10 <TEX>$\AA$</TEX>-bottom Al layer and oxidized it by varying oxidation time for 5, 10, 20 sec. Subsequent sputtering of 13 <TEX>$\AA$</TEX> - Al was performed and the matallic layer was oxidized for 120 sec. The electrical resistance changed from 700<TEX>$\Omega$</TEX> to 2700<TEX>$\Omega$</TEX> with increase of oxidation time, while variation of MR ratio was little spreading 27~31% which is larger than that of TMR device of ordinary single tunnel barrier. We calculated effective barrier height and width by measuring I-V curves, from which we found the barrier height was 1.3~1.5 eV, sufficient for tunnel barrier, and the barrier width(<16.2 <TEX>$\AA$</TEX>) was smaller than that of directly measured value by the tunneling electron microscopy. Our results may be caused by insufficient oxidation of Al precursor into <TEX>$Al_2O_3$</TEX>. However, double oxidized tunnel barriers were superior to conventional single tunnel barrier in uniformity and density. We found that the external magnetic field to switch spin direction of ferromagnetic layer of pinned layer breaking ferro-antiferro exchange coupling was increased as bottom layer oxidation time increased. Our results imply that we were able to improve MR ratio and tune switching field by employing double oxidized tunnel barrier process.

Facet-Facet Barrier on Surfaces: Proposal and Experimental Validation

ABSTRACTSurface processing is generally kinetics limited. Migration barriers, both on flat surfaces and near steps, therefore are of crucial importance. In this paper, we describe a kinetic barrier that separates two neighboring facets on surfaces. The contrast of this concept relative to the conventional Ehrlich-Schwoebel barrier is shown through molecular dynamics/statics calculations on copper and aluminum. The effects of this new kinetic barrier are demonstrated through lattice Monte Carlo simulations. The predicted effects are in direct correspondence with validation experiments on copper and silver thin films.

Improved Barrier and Adhesion Properties in Sputtered TaSiN Layer for Copper Interconnects

The barrier effect for copper diffusion and the adhesion properties of copper seed layers were studied for sputtered TaSiN layers. The diffusion depth of copper following 400°C annealing is as deep as 25 nm using conventional tantalum nitride (TaN) barrier layers. With the doping of Si in this layer to form TaSiN, the diffusion depth decreases drastically, reaching 5.0 nm for an optimum Si composition of 0.06-0.09 The stress of thin copper seed layers deposited on TaSiN is much lower than that on conventional Ta barrier layers, decreasing rapidly with increasing Si composition. There appears to be no agglomeration in the low stress copper seed layer. The highest adhesion strength is attained in a copper layer deposited on a TaSiN adhesion layer with a Si composition of 0.16. Note that the optimized Si composition is different between two layers, that is, the barrier and adhesion layers.

産業廃棄物を用いたコンクリート用骨材の開発 ゼロエミッションをめざして

It is urgent task for road administrators to establish a recycling system of the wastes in construction sites and rest areas on expressways. In this paper, it is reported the development of recycled concrete aggregate made from a part of the wastes and the test results of the performance of the concrete noise barrier that includes the recycled aggregate.As the results, the recycled concrete noise barrier has about the same level performance in terms of the effect of intercepting noise and the load-carrying capacity compared with that of the conventional concrete noise barrier. In addition, the cost of the recycled concrete noise barrier is 15% less than that of the conventional one.

Schottky junction properties of the high conductivity layer of diamond

Junction properties of Al/high-conductivity layer (HCL) near the surface of hydrogenated homoepitaxial diamond films were re-examined to evaluate the published models for the origin of HCL. As compared with the junction properties of metal/oxidized B-doped diamond films, it is confirmed that carrier transport in the Al/HCL junction can be well explained by the conventional Schottky barrier theory for metal/p-type semiconductors. This means that the carrier depletion region of HCL (i.e. the downward band bending for p-type HCL) actually exists in the vicinity of the Al/HCL junction at thermal equilibrium (zero bias) as well as at reverse bias conditions. To keep the downward band bending of HCL, ionized acceptors must exist in this region. We discuss a downward band-bending model based on the hydrogen-related shallow acceptors to explain electrochemical behaviors (adsorbate effect) of HCL as well as the present Schottky junction properties.

Characteristics of He/O 2 atmospheric pressure glow discharge and its dry etching properties of organic materials

In this study, the characteristics of atmospheric low temperature plasmas generated by capillary electrodes with capillary dielectrics were investigated for the application of microelectronic cleaning processes. The characteristics of the plasmas were studied as a function of capillary aspect ratios, input power, electrode distance, He/O 2 gas flow rate, etc., using a high voltage probe, current probe, and optical emission spectroscopy (OES). The voltage between the electrodes increased with the increase of input power, the increase of electrode distance, the decrease of He flow rate, and the increase of O 2 flow rate. The increase of the voltage has led to unstable filamentary discharge from the stable capillary discharge. The use of electrodes with capillary dielectrics instead of a conventional dielectric barrier electrode (the electrode covered with non-capillary dielectric) not only decreased the electrode voltage, therefore, increased the stability of the plasma but also increased the discharge current and, therefore, the intensity of the plasma. Increased ionization and dissociation of the plasma species could be observed by OES with the increase of input power in He/O 2 mixtures. However, with the increase of O 2 flow rate in a constant He flow rate, the emission peaks from He decreased due to the increased electron consumption by oxygen while the emission peaks from O 2 + and O increased due to the increased ionization and dissociation rates with the increase of oxygen concentration in the He/O 2 gas mixtures. Also, using a He/O 2 gas mixture, organic materials such as photoresist could be successfully removed with the average etch rates higher than 200 nm/min.

Water Vapor Permeation Theoryof“GREENWRAP”

It is well known that moisture barrier laminated paper sheets having a layer made from polyethylene can prevent permeation of moisture. But the conventional moisture barrier laminated paper is disadvantageous in that, after use, the paper sheets cannot be satisfactorily repulped and recycled.On the other hand, paper sheets having a layer made from wax and waterborne synthetic resin have moisture resistant and repulpability.But wax has problems to bleed out to the surface and transfer the contents or backside of sheets.We have developed a new recyclable moisture barrier paper that consists of a styrene-butadiene rubber (SBR) latex filled with plate-like fillers. The degree of the moisture barrier is equal to that of a polyethylene laminated paper.We have studied the Theory of the water vapor permeation which is to be explained by Maxwell tortuous effect.It has turned out that the permeability is significantly affected by the interface between the latex and fillers.It has been also found that plate-like fillers depress the solubility of the latex film.

A new 4H-SiC lateral merged double Schottky (LMDS) rectifier with excellent forward and reverse characteristics

The novel characteristics of a new Schottky rectifier structure, known as the lateral merged double Schottky (LMDS) rectifier, on 4H-SiC are explored theoretically and compared with those of the compatible conventional 4H-SiC Schottky rectifiers. The anode of the proposed lateral device utilizes the trenches filled with a high barrier Schottky (HBS) metal to pinch off a low barrier Schottky (LBS) contact during reverse bids. Numerical simulation of any such SiC structure is complicated by the fact that the thermionic emission theory predicts the reverse leakage current to be orders of magnitude smaller than the measured data. We, therefore, first propose a simple empirical model for barrier height lowering to accurately estimate the reverse leakage current in a SiC Schottky contact. The accuracy of the empirical model is verified by comparing the simulated reverse leakage current with the reported experimental results on different SiC Schottky structures. Using the proposed empirical model, the two-dimensional (2-D) numerical simulations reveal that the new LMDS rectifier demonstrates about three orders of magnitude reduction in the reverse leakage current and two times higher reverse breakdown voltage when compared to the conventional lateral low barrier Schottky (LLBS) rectifier while keeping the forward voltage drop comparable to that of the conventional LLBS rectifier.

Potential for biomolecular imaging with femtosecond X-ray pulses

Sample damage by X-rays and other radiation limits the resolution of structural studies on non-repetitive and non-reproducible structures such as individual biomolecules or cells. Cooling can slow sample deterioration, but cannot eliminate damage-induced sample movement during the time needed for conventional measurements. Analyses of the dynamics of damage formation suggest that the conventional damage barrier (about 200 X-ray photons per A2 with X-rays of 12 keV energy or 1 A wavelength) may be extended at very high dose rates and very short exposure times. Here we have used computer simulations to investigate the structural information that can be recovered from the scattering of intense femtosecond X-ray pulses by single protein molecules and small assemblies. Estimations of radiation damage as a function of photon energy, pulse length, integrated pulse intensity and sample size show that experiments using very high X-ray dose rates and ultrashort exposures may provide useful structural information before radiation damage destroys the sample. We predict that such ultrashort, high-intensity X-ray pulses from free-electron lasers that are currently under development, in combination with container-free sample handling methods based on spraying techniques, will provide a new approach to structural determinations with X-rays.

P‐47: High‐Luminous‐Efficiency Barrier‐Rib Structure in Color AC PDPs

AbstractWe suggest new types of barrier rib structure of color PDP—fish bone (FB type), semi box (SB type), embossing (EB type)—to achieve high luminous efficiency. The luminous efficiency has been increased, 15%∼18%, by adapting advanced barrier rib structure without any additional production process and mask.These structures provide wider phosphor area than stripe type structure does and higher exhausting speed compared with that of box type structure. The operating voltage of FB, SB, EB is almost the same with that of conventional barrier rib type.