Multilayer Resistance Research Articles

Investigation of multilayered packages resistance to free fall on the solid surface

The characteristics of deformations and behaviour of multilayered packages fall on the solid surface were analyzed. The force impulses by using measuring equipment, which was connected to the PC were determined. The visual process of package deformation was captured by the high - speed camera. The obtained results allowed to decide, what height or what static state before fall is the most dangerous for the package. Test results are applied in the further process of packages designing.http://dx.doi.org/10.5755/j01.mech.17.2.328

An enhancement of via profile using MLR mask

The fabrication process of semiconductor is more and more difficult as scaling down. Especially, the via profile formation is one of the main challenges which is suffering from making stable device process because ArF photo resist (PR) itself can not provide proper etch selectivity to sub-layers.Recently, many researches have been studied for the via process in terms of photo property, etch property and process compatibility using bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist (MLR) process. In this paper, we proposed and demonstrated for beyond 90nm scaled logic via process consisting of high-k inter metal dielectric (IMD) using multi-layer resist (MLR) organic hard mask.Based on the test results described in this paper, the results show the higher etching selectivity to each layer and also helped to easily control the anisotropic profiles.

Observation of room temperature negative differential resistance in multi-layerheterostructures of quantum dots and conducting polymers

Multi-layer heterostructure negative differential resistance devices based on poly-[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV) conducting polymer and CdSequantum dots is reported. The conducting polymer MEH-PPV acts as a barrier while CdSequantum dots form the well layer. The devices exhibit negative differential resistance(NDR) at low voltages. For these devices, strong negative differential resistance is observedat room temperature. A maximum value of 51 for the peak-to-valley ratio of current isreported. Tunneling of electrons through the discrete quantum confined states in the CdSequantum dots is believed to be responsible for the multiple peaks observed in theI–V measurement. Depending on the observed NDR signature, operating mechanisms areexplored based on resonant tunneling and Coulomb blockade effects.

GOLD NANOPARTICLE-INCORPORATED POLYELECTROLYTE MULTILAYER FOR SENSITIVE ELECTROCHEMICAL IMMUNOSENSING

Reported was a novel amperometric immunosensor based on layer-by-layer (LbL) assembled polyethylenimine/gold nanoparticles/poly (acrylic acid) (PEI/AuNPs/PAA) multilayer. The assembly process was in situ monitored by surface plasmon resonance (SPR) technique. Anti-goat IgG as a capture antibody was covalently immobilized on the outermost PAA layer of the multilayer to construct an immunosensor. A target protein, goat IgG was electrochemically detected with alkaline phosphatase-conjugated anti-goat IgG (ALP-anti-goat IgG) as a recognition antibody. Electrochemical investigations suggest that the incorporation of AuNPs facilitates the electron transfer between the underlying electrode and the redox species in solution, and thus enhances the electrochemical signals and in turn improves the immunosensing performance. A detection limit of 100 pg mL-1 with a dynamic range of five orders of magnitude was achieved. Due to the protein-friendly environment and the protein resistance of the polyelectrolyte multilayer, the resulting immunosensor demonstrates excellent storage stability, satisfying assay specificity.

Preparation and study on performance of submicron nickel powder for multilayer chip positive temperature coefficient resistance

Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance (PTCR). The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200–300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co—fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction (XRD) and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions: If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni2+, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70–80 °C, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2+ is 4, when molar ratio of (C2H5O)2/Ni2+ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.

The Resistance of Polyelectrolyte Multilayers in a Free-Hanging Configuration

The resistivity ρ(PEM) of polyelectrolyte multilayers (PEMs), PEI(PSS/PAH)(24), PEI(PGA/PAH)(12), PEI(HA/PLL)(12) and PEI(PSS/PLL)(12), in a free-hanging configuration was estimated combining electrochemical impedance spectroscopy (EIS) and atomic force microscopic (AFM) images. Surprisingly, the obtained value of several kΩcm is at least 6 orders of magnitude lower than that reported previously, where the resistivity was determined in the conventional PEM-on-electrode system. The significant discrepancy indicates the unexpectedly low electrical PEM resistance in the absence of redox-active ions and the sensitivity limitation in the conventional system.

Thermally induced decomposition of B4C barrier layers in Mo/Si multilayer structures

We investigate the influence of the Mo crystalline state (quasi-amorphous or crystalline) on the thermal stability of Mo/Si thin film multilayers with B4C diffusion barrier layers at either of the two interfaces. We find that multilayers containing amorphous Mo layers are more stable than those containing crystalline layers. This observation is in contrast to the case where Si3N4 diffusion barriers are used. Using X-ray diffraction, X-ray reflection and X-ray photo-electron spectroscopy we show that this difference can be attributed to the dissociation of B4C followed by diffusion of B in Mo. Due to the favorable thermodynamic properties of MoxBy compounds, the boron atoms react with the Mo layer, forming a MoxBy layer that effectively improves the multilayer thermal resistance.

Thin Ag Layer Inserted GZO Multilayer Grown by Roll-to-Roll Sputtering for Flexible and Transparent Conducting Electrodes

We prepared a nanoscale Ag-layer-inserted Ga-doped ZnO (GZO) multilayer on a flexible poly(ether sulfone) (PES) substrate using a continuous roll-to-roll (RTR) sputtering system at room temperature for the fabrication of highly flexible and transparent conducting oxide electrodes. When the thickness of the Ag interlayer was optimized (12 nm), the resulting GZO/Ag/GZO (GAG) multilayer showed a resistivity of and a transparency of 87.2% without in situ or ex situ annealing processes. However, although it exhibited lower resistivity, the GAG multilayer showed decreased optical transparency above the critical Ag interlayer thickness of 12 nm due to severe light scattering caused by the Ag layer. The results of bending tests demonstrated that the GAG multilayer resistance varies depending on the bending radius of the sample during repeated bending cycles. The constant surface morphology and resistance of the GAG multilayer even after the performance of bending tests indicate that RTR sputter grown GAG multilayers are promising as flexible transparent conducting electrodes for use in cost-efficient flexible displays and photovoltaics.

Competing effects of silanol surface concentration and solvent dielectric constant on electrostatic layer-by-layer assembly of silica nanoparticles on gold

Two types of silica nanoparticles having differing concentrations of ionizable surface groups are used to investigate the interplay between nanoparticle surface charge and solvent dielectric constant in nanostructure development during layer-by-layer assembly with a cationic polyacrylamide. Zeta ( ζ) potential measurements are used to determine the extent of silanol dissociation with pH. For 19-nm-diameter X-Tec 3408 silica nanoparticles from Nano-X GmbH (NanoX), complete dissociation yields a ζ-potential value of about −44 mV and occurs between pH 5 and 6 in 50% ethanol-in-water mixture by volume. By contrast, 65-nm-diameter polishing silica from Electron Microscopy Supply (EMS) has a ζ potential that does not equilibrate even up to pH 7 with a value of −59 mV under otherwise similar solution conditions. The more negative zeta potential at a given pH is found to substantially reduce nanoparticle adsorption. This behavior is opposite that observed when the dielectric constant of the suspension is decreased, independent of particle size. Nanoparticle surface chemical heterogeneity is discussed as a plausible explanation for such seriously discrepant behavior and the effects on multilayer electrical contact resistance for proton-exchange membrane (PEM) fuel-cell coating applications are presented.

The Prediction of the Air Resistance of Woven Fabrics and Multilayers of Fabric Based on Fabric Structure

The Prediction of the Air Resistance of Woven Fabrics and Multilayers of Fabric Based on Fabric Structure

Mechanical and tribological properties of Ti/TiAlN duplex coatings on high and low alloy tool steels

In this research work, different steels were hardened using plasma nitriding process in an Arc-PVD device. Afterwards, on both non-nitrided and plasma nitrided substrates, different Ti/TiAlN multilayer coatings were deposited by a magnetron sputtering device. Scratch tests were performed on the duplex systems in order to characterize their adhesive properties. The failure modes of individual coating systems under various normal loads were described using light optical microscope. Furthermore, to study the effect of plasma nitriding on the friction coefficient and wear rate of the systems, ball-on-disc tests were carried out. It was shown that high and low alloy tool steels obtained different levels of hardness after plasma nitriding process. The results of scratch tests showed that both Ti/TiAlN multilayer coatings have a higher adhesion to plasma nitrided steels compared to non-nitrided steels. In addition, plasma nitriding of the substrates resulted in an increase in the wear rates of multilayer coatings. It was also revealed that the adhesion and the tribology of multilayers depend strongly on the amount of titanium interlayers. An increase of the thickness of titanium interlayers enhanced the adhesion of multilayers. However, increasing the thickness of titanium interlayers decreased the hardness and wear resistance of multilayers.

Effect of Ag thickness on electrical transport and optical properties of indium tin oxide–Ag–indium tin oxide multilayers

We report the dependence of electronic and optical properties on the Ag thickness in transparent conductive indium tin oxide (ITO)-Ag-ITO (IMI) multilayer films deposited on polyethylene naphthalate flexible substrate by sputtering at room temperature. The electrical properties (such as carrier concentration, mobility, and resistivity) changed significantly with incorporation of Ag between the ITO layers. Comparison of sheet resistance of the IMI multilayers and the calculated sheet resistance of the Ag midlayer indicates that most of the conduction is through the Ag film. The critical thickness of Ag to form a continuous conducting layer is found to be 8 nm using electrical and optical analysis. A conduction mechanism is proposed to elucidate the mobility variation with increased Ag thickness. Carrier transport is limited by either interface scattering or grain-boundary scattering depending on the thickness of the Ag midlayer. Interface scattering is dominant for thinner (5.5–7 nm) Ag and grain-boundary scattering is dominant for thicker (8–10.5 nm) Ag midlayers. In addition, the effect of varying Ag midlayer thickness on transmittance behavior is also discussed. A figure of merit is used to compare performance of the IMI multilayer systems as a function of Ag thickness.

An inhibitory interaction between viral and cellular proteins underlies the resistance of tomato to nonadapted tobamoviruses

Any individual virus can infect only a limited range of hosts, and most plant species are "nonhosts" to a given virus; i.e., all members of the species are insusceptible to the virus. In nonhost plants, the factors that control virus resistance are not genetically tractable, and how the host range of a virus is determined remains poorly understood. Tomato (Solanum lycopersicum) is a nonhost species for Tobacco mild green mosaic virus (TMGMV) and Pepper mild mottle virus (PMMoV), members of the genus Tobamovirus. Previously, we identified Tm-1, a resistance gene of tomato to another tobamovirus, Tomato mosaic virus (ToMV), and found that Tm-1 binds to ToMV replication proteins to inhibit RNA replication. Tm-1 is derived from a wild tomato species, S. habrochaites, and ToMV-susceptible tomato cultivars have the allelic gene tm-1. The tm-1 protein can neither bind to ToMV replication proteins nor inhibit ToMV multiplication. Here, we show that transgenic tobacco plants expressing tm-1 exhibit resistance to TMGMV and PMMoV. The tm-1 protein bound to the replication proteins of TMGMV and PMMoV and inhibited their RNA replication in vitro. In one of the tm-1-expressing tobacco plants, a tm-1-insensitive TMGMV mutant emerged. In tomato protoplasts, this mutant TMGMV multiplied as efficiently as ToMV. However, in tomato plants, the mutant TMGMV multiplied with lower efficiency compared to ToMV and caused systemic necrosis. These results suggest that an inhibitory interaction between the replication proteins and tm-1 underlies a multilayered resistance mechanism to TMGMV in tomato.

A new model of bi-directional ammonia exchange between the atmosphere and biosphere: Ammonia stomatal compensation point

A new multi-layer canopy resistance model of bi-directional NH 3 exchange is presented. This new model, which is based on the Multi-Layer BioChemical deposition (MLBC) model [Wu, Y., Brashers, B., Finkelstein, P.L., Pleim, J.E., 2003a. A multiplayer biochemical dry deposition model. I. Model formulation. J. Geophys. Res. 108, D1; Wu, Y., Brashers, B., Finkelstein, P.L., Pleim, J.E., 2003b. A multiplayer biochemical dry deposition model. II. Model evaluation. J. Geophys. Res. 108, D1], incorporates a parameterization for the ammonia stomatal compensation point that is theoretically derived to consider the effects of leaf temperature and apoplastic concentrations of NH 4 + and H +. The new ammonia stomatal compensation point scheme accounts for the effects of deposition, emission and leaf temperature on the dynamics of apoplast [NH 4 +] and [H +]. The new model is evaluated against bidirectional NH 3 fluxes measured over fertilized soybean. The general patterns of observed deposition and emission are successfully reproduced when the ammonia stomatal compensation point is included. Driven by the effects of deposition, emission and leaf temperature, modeled apoplastic [NH 4 +] and [H +] display significant diurnal variation when the buffer effect of the underlying metabolic processes generating or consuming NH 4 + were ignored. Model predictive capability is improved slightly by incorporating the feedback into a dynamic stomatal compensation point. A simple implementation of the feedback mechanism in the current model provides opportunities for improvement. While the stomatal flux is shown to be an important process in the regulation of canopy-scale fluxes, it appears that exchange with leaf surface water and soil may also be important.

Effect of annealing on magnetotransport and structural properties of Ni70Co30/Cu multilayers

The effect of annealing on magnetotransport and structural properties of Ni70Co30/Cu multilayers is investigated. The GMR signal remains stable up to 175 °C and almost disappears at 285 °C. The total resistivity of multilayers is nearly constant below 175 °C and rapidly increases after annealing at 285 °C. By the combination of x-ray reflectivity, x-ray diffuse scattering and extended x-ray absorption fine structure (EXAFS) techniques, it is found that Ni atoms and Cu atoms occupy preferentially the interfacial position of the multilayer and the interface roughness is mainly caused through the diffusion of Cu and Ni in the grain boundary during the deposition. After 285 °C annealing, the interface roughness increases remarkably and the interfacial lateral correlation length and the fractal exponent of Co, Ni and Cu decrease significantly. At the same time, the differences in the interfacial lateral correlation lengths of Co, Ni and Cu also becomes smaller. This suggests that the intermixing of adjacent layers takes place. It can be concluded that the degradation mechanism of the GMR effect on the annealed Ni70Co30/Cu multilayer is the compositional mixing at the interfaces, rather than the interlayer diffusion of atoms along the grain boundary.

Novel Spin-on Carbon Hard Mask with Hardening by Ion Implantation

In this article, we present a novel high-performance multi-layer resist (MLR) process that uses a spin-on carbon (SOC) hard mask (HM). In the process, a technique involving the implantation of ions into the SOC just after coating was employed. B, P, Ar, and As were implanted in order to compare the degrees of hardening for the same dose amount (1E+15) and equivalent mean projected range Rp (ca. 75 nm); the parameters were controlled by dose energy for each ion. The results indicated that heavier ions with high dose energy showed higher hardening efficiency. The hardening depth in the SOC film approximately corresponded to the mean projected range (Rp). These findings were consistent with the physics of ion implantation, in which elastic and inelastic collisions between ions and target atoms and electrons are considered. As a next step, we attempted to apply this process to form ultra-thin lines using the implantation of Ar ions as an inert species. We confirmed that by using this system, the fundamental lithographic performance obtained was equivalent to that obtained by using the conventional MLR system. Furthermore, excellent etching performance was obtained when the implantation was carried out at higher dose energies. Accordingly, the formation of ultra-thin lines (ca. 25 nm) was successfully achieved by tuning the hardening condition.

Development of Multilayer Resist Technology for Halftone Mask in Liquid Crystal Display Manufacturing

A halftone mask was used in a lithography process to reduce the number of steps required in liquid crystal display (LCD) manufacturing. Three thicknesses of resist films were produced using the halftone mask. Since the resist is exposed in the area where the sensitivity curve rises, a problem arises in that the thickness of the resist film fluctuates drastically when the exposure dose to the resist fluctuates slightly. We tried to stabilize the film thickness using two kinds of resists having different sensitivities. We used a low-sensitivity resist as a lower layer and a high-sensitivity resist as an upper layer. However, it was not possible to produce a stable film thickness because the two resists blended at the interface. Therefore, we added an aqueous polymer solution as an intermediate layer between the resists which were dissolved in a solvent. This solved the blending problem and a stable film thickness was obtained.

Oxidation resistance and microstructure of ruthenium-capped extreme ultraviolet lithography multilayers

The oxidation resistance of protective capping layers for extreme ultraviolet lithography (EUVL) multilayers depends on their microstructure. Differently prepared Ru-capping layers, deposited on Mo/Si EUVL multilayers, were investigated to establish their baseline structural, optical, and surface properties in as-deposited state. The same capping layer structures were then tested for their thermal stability and oxidation resistance. The best performing Ru-capping layer structure was analyzed in detail with transmission electron microscopy (TEM). As compared to other Ru capping layers preparations studied here it is the only one that shows grains with preferential orientation. This information is essential for modeling and performance optimization of EUVL multilayers.

Electrically isolated nanostructures fabricated using self-assembled multilayers and a novel negative-tone bi-layer resist stack

We create metal nanoelectrode structures with precise proximal placement by blending traditional top-down and bottom-up lithography. Multiple levels of conventional lithography are used in combination with self-assembled multilayer resists (molecular rulers) to generate metallic electrode structures with nanoscale spacings. These multilayers are deposited on initial lithographic gold electrode structures forming a type of lift-off resist used to fabricate proximally placed secondary metal structures with nanometer-scale resolution. By controlling the thicknesses of these multilayers, selective self-assembly is exploited to generate molecular ruler resists, enabling the creation of tailored nanogaps in the 10–50 nm regime. The ability to fabricate electrically isolated nanoelectrodes would enable reliable measurement of the conducting properties of single molecules, nanoparticles and other low-dimensional materials. This paper outlines a new process using a lift-off resist (LOR)/SU-8 negative-tone bi-layer stack to improve the yield of nanoelectrodes. SU-8 finds application in a variety of fabrication techniques, but is difficult to release from the substrate. The LOR/SU-8 process that we have developed possesses the following additional advantages: easy chemical removal of the resist stack with the LOR acting as a release layer, creation of metal lift-off patterns with near-vertical sidewalls, and the ability to withstand chemical processing.

Buffer-Enhanced Electrical-Pulse-Induced Resistive Memory Effect in Thin Film Perovskites

A multilayer perovskite thin-film resistive memory device composed of a Pr0.7Ca0.3MnO3 (PCMO) perovskite oxide epitaxial layer on a YBa2Cu3O7-δ (YBCO) thin-film bottom electrode, a thin yttria-stabilized zirconia (YSZ) buffer layer grown on the PCMO layer, and a gold thin-film top electrode has been developed. With the addition of the YSZ buffer layer, the pulse voltage needed to switch the device is significantly reduced and the resistance-switching ratio is increased compared to a non buffered resistive memory device, which is very important for device fabrication. The magnetic field effect on the multilayer structure resistance at various temperatures shows colossal magnetoresistance (CMR) behavior for both high and low resistance states, implying a bulk material component in the switch behavior. The multilayer thin-film lattice structure has been further characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, which indicate a high-quality heterostructure. Current imaging atomic force microscopy (I-AFM) analysis indicated nanogranular conductivity distributed uniformly throughout the PCMO film surface.