Cu nanoparticles were synthesized via electrochemical deposition and the effect of the addition of poly(N-vinyl-pyrrolidone) (PVP) and pH on the properties of the nanoparticles was investigated. The Cu nanoparticles were prepared from an electrolyte containing copper acetate (pH 5.50) or copper sulfate (pH 4.14) by collecting the dispersed particles in the solution after electrochemical reduction. With the use of the acetate bath, formation of Cu2O at -0.2 and -1.5 V vs. Ag/AgCl was confirmed. On the other hand, Cu2O formation was not observed with the sulfate bath due to the lower pH, and the Cu nanoparticles could not be obtained at the potential of -1.5 V vs. Ag/AgCl. Surface enhanced Raman spectroscopy with plasmon sensors was used to investigate the transformations of PVP during electrolysis under the different conditions when Cu particles were and were not formed. For the dispersed nanoparticles in the electrolyte, it was observed that the C=O and C-N peaks of PVP also exhibited a red-shift. It was thus confirmed that PVP was coordinated to both the cathode electrode and dispersed nanoparticles in the electrolyte upon electrochemical reduction.

A corporate-feed slotted waveguide array antenna with broadband characteristics in terms of gain and reflection in the 350-GHz band is proposed. To improve the etching accuracy of the thin laminated plates with the conventional diffusion bonding process, a new fabrication process has been developed, where the etching accuracy is lower than +/- 5 mu m. In this process, the laminated plates are made with silicon wafers and etched by deep reactive ion etcher process. These are gold plated then bonded with the diffusion bonding process. The estimated effective conductivity of the gold plated wafer is 1.6 x 10(7) S/m. The loss per unit length is 1.1 dB/cm. A 16x16 element array antenna has been designed and fabricated in the 350-GHz band with the proposed process. The broadband characteristic in terms of the antenna gain is demonstrated for the first time by measurement in this frequency band. The 3-dB down gain bandwidth is 50.8 GHz in simulation and is 44.6 GHz in measurement.

We present a novel optical device for the analysis of chemical surface properties utilizing surface-enhanced Raman scattering. The device, a transmission-type plasmonic sensor (TPS), offers the advantages of high sensitivity, nondestructive sample characterization, simple setup, and low-cost fabrication. The TPS is composed of Ag nanoparticles (NPs) deposited on a convex quartz glass substrate. The enhanced Raman spectrum is acquired by focusing a laser beam perpendicular to the sample surface through the substrate. The laser beam generates plasmon polarization in droplet-shaped Ag NPs at the sensor/sample interface. Our results indicate the potential of the device as a versatile surface-analytical tool. (C) 2016 The Japan Society of Applied Physics

We present a novel optical device for the analysis of chemical surface properties utilizing surface-enhanced Raman scattering. The device, a transmission-type plasmonic sensor (TPS), offers the advantages of high sensitivity, nondestructive sample characterization, simple setup, and low-cost fabrication. The TPS is composed of Ag nanoparticles (NPs) deposited on a convex quartz glass substrate. The enhanced Raman spectrum is acquired by focusing a laser beam perpendicular to the sample surface through the substrate. The laser beam generates plasmon polarization in droplet-shaped Ag NPs at the sensor/sample interface. Our results indicate the potential of the device as a versatile surface-analytical tool. (C) 2016 The Japan Society of Applied Physics

We present a novel optical device for the analysis of chemical surface properties utilizing surface-enhanced Raman scattering. The device, a transmission-type plasmonic sensor (TPS), offers the advantages of high sensitivity, nondestructive sample characterization, simple setup, and low-cost fabrication. The TPS is composed of Ag nanoparticles (NPs) deposited on a convex quartz glass substrate. The enhanced Raman spectrum is acquired by focusing a laser beam perpendicular to the sample surface through the substrate. The laser beam generates plasmon polarization in droplet-shaped Ag NPs at the sensor/sample interface. Our results indicate the potential of the device as a versatile surface-analytical tool.

We report the fabrication and evaluation of the Cu/Bi bilayer absorber with electrodeposition. We designed the Cu/Bi absorber to satisfy the requirements for scanning transmission electron microscope (STEM). The residual resistivity ratios of films of Cu and Bi with electrodeposition was and , respectively; these values are sufficient for the requirements of STEM. We found that the Cu/Bi bilayer absorber TES microcalorimeter experienced a pulse-shape variation and we considered that these variations were caused by the quality of the contact surface between the absorber and TES. In addition, we examined the structure of the absorber using focus ion beam analysis and STEM. The results suggest that an oxidation between the Cu and seed layer, in which the layer is an electrode for electrodeposition, yielded variations. Moreover, thermal simulation suggests that the thermal conduction between the absorber and TES caused variations. The results of this study will improve the process of Bi electrodeposition.

A corporate feed slotted waveguide array antenna with broadband characteristics in term of gain in the 350 GHz band is achieved by measurement for the first time. The etching accuracy for thin laminated plates of the diffusion bonding process with conventional chemical etching is limited to +/- 20 mu m. This limits the use of this process for antenna fabrication in the submillimeter wave band where the fabrication tolerances are very severe. To improve the etching accuracy of the thin laminated plates, a new fabrication process has been developed. Each silicon wafer is etched by DRIE (deep reactive ion etcher) and is plated by gold on the surface. This new fabrication process provides better fabrication tolerances about +/- 5 mu m using wafer bond aligner. The thin laminated wafers are then bonded with the diffusion bonding process under high temperature and high pressure. To validate the proposed antenna concepts, four antenna prototypes have been designed and fabricated in the 350 GHz band. The 3dB-down gain bandwidth is about 35GHz by this silicon process while it was about 15GHz by the conventional process using metal plates in measurement.

A corporate feed slotted waveguide array antenna with broadband characteristics in term of gain in the 350 GHz band is achieved by measurement for the first time. The etching accuracy for thin laminated plates of the diffusion bonding process with conventional chemical etching is limited to +/- 20 mu m. This limits the use of this process for antenna fabrication in the submillimeter wave band where the fabrication tolerances are very severe. To improve the etching accuracy of the thin laminated plates, a new fabrication process has been developed. Each silicon wafer is etched by DRIE (deep reactive ion etcher) and is plated by gold on the surface. This new fabrication process provides better fabrication tolerances about +/- 5 mu m using wafer bond aligner. The thin laminated wafers are then bonded with the diffusion bonding process under high temperature and high pressure. To validate the proposed antenna concepts, an antenna prototype has been designed and fabricated in the 350 GHz band. The 3dB-down gain bandwidth is about 44.6 GHz by this silicon process while it was about 15GHz by the conventional process using metal plates in measurement.

A corporate feed slotted waveguide array antenna with broadband characteristics in term of gain in the 350 GHz band is achieved by measurement for the first time. The etching accuracy for thin laminated plates of the diffusion bonding process with conventional chemical etching is limited to +/- 20 mu m. This limits the use of this process for antenna fabrication in the submillimeter wave band where the fabrication tolerances are very severe. To improve the etching accuracy of the thin laminated plates, a new fabrication process has been developed. Each silicon wafer is etched by DRIE (deep reactive ion etcher) and is plated by gold on the surface. This new fabrication process provides better fabrication tolerances about +/- 5 mu m using wafer bond aligner. The thin laminated wafers are then bonded with the diffusion bonding process under high temperature and high pressure. To validate the proposed antenna concepts, an antenna prototype has been designed and fabricated in the 350 GHz band. The 3dB-down gain bandwidth is about 44.6 GHz by this silicon process while it was about 15GHz by the conventional process using metal plates in measurement.

A Pi-structured Bi-Te micro-thermoelectric device with a large upper electrode, i.e., an umbrella-type device, was fabricated via electrodeposition, and the effect of the size of the electrode was evaluated. The Bi-Te thermoelectric materials were electrodeposited from HNO3-based aqueous electrolyte. The device consisted of eight arrays, each consisting of 110 thermoelectric units, each of which was electrodeposited onto the patterned substrate with an array of 50 x 50 mu m(2) holes that were 20 mu m deep. The deposition conditions for the n-type and p-type Bi-Te films were optimized to enable patterned electrodeposition of the materials to yield dense and uniform deposits. Accordingly, the materials were selectively deposited in a pattern to fabricate the thermoelectric micro-device. The resultant umbrella-type device, whose electrode is 1.65 times larger than smaller electrode, generated 4.57 times more power than the device with a smaller electrode. Therefore, we confirmed the improvement power by using an umbrella-type device. (C) 2014 Elsevier Ltd. All rights reserved.

TiO2 nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO2 nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM.

Recently, several materials and joining processes have been proposed as alternatives to high-Pb-containing solders. There has been an increasing focus on developing solid-state bonding interconnection processes based on sintering, such as bonding techniques using Ag or Cu nanoparticles. However, sintered nanoparticle layers tend to have voids that result from solvent residue and dispersing agents. The voids in the sintered layer degrade the reliability of the joints. Therefore, we have proposed a solid-state bonding technique without solvents and flux using a nanoporous sheet. A nanoporous sheet can be made from binary alloy systems by dissolving the less noble component from the alloy selectively. A bonding technique using nanomaterials could reduce the bonding temperature because of the high reactive nanoporous surface. In this study, Au nanoporous sheets were fabricated by dealloying a Au-Ag alloy into an HNO3 solution, and the effects of the Au nanoporous structure on joint bonding strength were investigated. After dealloying, Au nanoporous sheets were set between bare Cu substrates. The samples were bonded at various process temperatures under a nitrogen atmosphere. As a result, the joint bonded at 300 degrees C, using the Au nanoporous sheet with a dealloying time of 1 h, showed a high shear strength of about 20 MPa. It was found that joining using Au nanoporous bonding was successfully achieved.

© 2015 International Union of Radio Science (URSI).This paper presents the fabrication of plate-laminated waveguides and cavities for 350GHz band by silicon process where the tolerance is less than several μm. We measure the transmission loss of the waveguide and the Q factors of the cavities, and then estimate the equivalent conductivity. We will also fabricate the plate-laminated waveguide slot array antennas (Y.Miura, J.Hirokawa et al., IEEE Trans. Antennas Propagat., 59, 2011, pp.2844-2851) and show the measured results in the conference.

In this paper, we propose several types of planar micro-electromagnetic actuator that can be applied in micro-pumps and micro-valves. The various types each consist of a thin film permanent magnet (TFPM), a micro-coil and, in some cases, a ferromagnetic layer. The magnetic properties of a TFPM with a multilayered structure, comprising 300 nm thick NdFeB and 10 nm thick Ta layers deposited sequentially, are as high as bulk NdFeB magnets. Conventional micro-electromagnetic actuators consist of a bulk permanent magnet and a spiral micro-coil, whereas the actuators proposed in this paper consist of segmented patterns of TFPM, such as line/space and chessboard patterns, and mesh coils surrounding the segmented patterns. The TFPMs are segmented in order to reduce the demagnetization effect and to generate a large flux density. The proposed micro-coils possess a 2D structure and are easy to fabricate compared with spiral type micro-coils. The results of simulation show that the electromagnetic forces generated by actuators with segmented TFPMs are several times higher than one without segmentation. Furthermore, the actuation force performance is enhanced by covering the TFPM pattern with a ferromagnetic layer of Ni55Fe45 permalloy. The electromagnetic actuators are fabricated by a fully integrated MEMS process. The measured magnetic flux densities generated by the patterned TFPMs agree with the simulated results. The electromagnetic force between the patterned TFPM and the micro-coil is measured by an electronic force balance. Due to alignment errors between the micro-magnet and micro-coil, the experimentally measured forces are from 70% to 90% of the simulated ones. (C) 2014 Elsevier B.V. All rights reserved.

The effect of the annealing temperature on the magnetostrictive properties of Fe-Co alloy thin films on quartz glass was systematically investigated. The saturation magnetostriction was 56 ppm for the Fe32Co68-sputtered thin film quenched from 673 K, and it increased to 159 ppm with increasing annealing temperature up to 1073K. The magnetostriction above 1093K significantly decreased with the emerging fcc phase in the Fe-Co alloy. SEM images showed that the crystal grains present in the fcc phase aggregated to form a discontinuous surface, which resulted in a decrease in the effective magnetostriction. Measurements of the magnetic properties by vibrating sample magnetometer and magnetic force microscopy revealed the enhancement of the magnetization at the crystal grain boundaries of Fe-Co alloy thin films with large magnetostriction. Thus, the heterogeneity of the magnetization can play a key role in inducing the large magnetostrictive effect.

We proposed low-temperature Au-Au bump interconnects bonding using nanoporous Au-Ag powders as a connective adhesion. The nanoporous powders were formed by de-alloying Au-Ag alloy in HNO3 solution. To optimize the pore size, the influence of the annealing temperature on the porous structures was investigated. Selective transfer of the nanoporous powders on bumps was obtained by stamping process. Bonding strength of about 2.4 MPa was achieved at 150 degrees C by using nanoporous Au-Ag powders. Bonding interface was evaluated by scanning acoustic microscope and scanning electron microscopy. This result indicated that the nanoporous powder is a useful material for low-temperature Au-Au bonding.

A NiP imprinting mold with patterns, whose size is from nanometer to submicrometer (170, 500, and 1000nm diameter), was fabricated by electroless deposition of NiP on a 3-aminopropyltriethoxysilane (APTES) modified master mold. The NiP deposit as a replicate mold was then detached from the master mold. The initial NiP deposition in patterns of the master mold was investigated
moreover, nanoindentation was successfully performed on a single NiP pattern for investigating the hardness. The NiP had a similar grain size in different sizes of patterns of the master mold during the initial deposition, as well as the same hardness of the NiP patterns (approximately 12 GPa) was observed. These results indicated that the initial NiP deposition and hardness of NiP were not size dependent above 170 nm. The surface morphology of the NiP detached from the master mold and NiP pattern of different sizes were investigated as well. © 2013 The Japan Society of Applied Physics.

An electroless NiP imprinting mold was fabricated through replication of a cyclo-olefin polymer (COP) master mold. The NiP was electrolessly deposited on a nanopatterned COP master mold, pretreated by ultraviolet (UV) irradiation prior to modification with 3-aminopropyltriethoxysilane (APTES). The NiP deposit as a "replicate" was then detached from the COP master mold. Additionally, by optimizing the UV irradiation period, APTES could be formed on the COP master mold for electroless deposition without disturbing the nanopattern geometry of the COP master mold. The water contact angle and surface morphology of the COP surface, and the adhesion strength between deposited NiP and the COP surface were investigated. © 2013 The Electrochemical Society of Japan, All rights reserved.

In this study, we proposed low-temperature Au-Au bonding using nanoporous Au-Ag sheets, fabricated by dealloying a Au-Ag sheet in HNO3 solution, as a joint layer. The influence of the annealing temperature on the pore structure and chemical properties of the sheets was investigated. The chemical composition of the sheet was analyzed by X-ray photoelectron spectroscopy (XPS). It was found that the strength of Au-Au bonding with the nanoporous sheet increased. A sheet treated with liquid N-2 was also tested; the strength of the Au-Au bond increased as a result of this low-temperature treatment. (c) 2013 The Japan Society of Applied Physics

Electrical resistivity measurements in the temperature range from 6 to 300K were carried out in order to investigate the effects of the hydrogen absorption on the transport properties of Ni36Nb24Zr40 amorphous alloy ribbon. The electrical resistivity basically behaved negative temperature dependence in all prepared specimens of (Ni0.36Nb 0.24Zr0.40)100-xHx with 0 ≤ x &lt
15. The absolute value of temperature coefficient of the resistivity, TCR, increased with increasing the amount of the absorbed hydrogen. In addition, it was also clear that the electrical resistivity gradually increased with the time just after electrochemically charging, and tended to saturate after about 800 ks at 300 K. The behavior of the gradual increase in the electrical resistivity with the time was explained by the model including two kinds of the relaxation times, being associated with the migration of the hydrogen from the sample surface. © 2013 The Japan Institute of Metals and Materials.

A nanoimprint lithography mold was fabricated through electroless deposition combined with self-assembled monolayer (SAM) modification. To copy nanopatterns as "replicates", NiP was electrolessly deposited on a nanopatterned master mold (made of SiO2/Si), whose surface was modified with 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (TAS). NiP deposits were then manually detached from the mold. SAM improves Pd catalyst coverage for electroless deposition, further improving the morphology of the electroless deposition of NiP on the nanopatterned master mold and controlling the adhesion strength between electroless deposited NiP and the nanopatterned master mold to a level appropriate for smooth detachment. The initial catalyzation process and mechanical properties (such as, the hardness and adhesion strength of the SiO2 substrate) of electroless deposited NiP were also systematically investigated. (c) 2012 Elsevier Ltd. All rights reserved.

Chemical structure of ultra-thin lubricant film/DLC overcoat for 4Tbpsi and more was measured with plasmonic sensor and surface-enhanced Raman scattering spectroscopy. Depth profile of the chemical structure for the film system was also measured with a depth resolution of 0.1nm.

We investigated the laterally enhanced growth of electrodeposited Au for fabricating nanogap electrodes. To enhance the lateral growth, we carried out electrodeposition over patterned electrodes onto a SiO2 surface modified with self-assembled monolayers (SAMs) or dendrimers with amine groups. The morphology and thickness of the Au films were controlled by adjusting deposition conditions such as duration, applied potential, and Au ion concentration in the bath. To investigate the mechanism of the laterally enhanced growth, the surface states of SAM- or dendrimer-modified SiO2 were analyzed by X-ray photoelectron spectroscopy (XPS). The XPS results indicate the existence of organic molecules and Au ions on the SiO2 surface, which suggests that laterally enhanced growth is induced by the Au ions coordinated on the amine groups of the organic molecules. To further analyze the mechanism of the laterally enhanced growth, we investigated the relationship between the morphology of the laterally enhanced growth of Au and the amount of Au ions on organic molecules. The laterally enhanced growth of Au is expected to be useful for fabricating thin film nanogap electrodes. (C) 2012 Elsevier Ltd. All rights reserved.

Ultra-thin DLC films and lubricant films are requested for high density magnetic recording. It was difficult for Raman spectroscopy to measure their molecular structures because of its low sensitivity. Newly-developed plasmonic sensor successfully acquired Raman spectrum of DLC films or lubricant/DLC interfaces with sub-nanometer thickness. Crystal structure of ultra-thin DLC films were slightly changed compared with that of thick films. Specifically, a graphite-like structure increases with decreasing thickness. It was found that organic and inorganic contaminations exist on a magnetic layer or a magnetic layer/DLC interface. According to the Raman spectrum analysis, a feature of adsorbed lubricant molecules of lubricant on the DLC film was confirmed.

In this study, we evaluate the hardness and morphology of Al layers, which are constructed using Al / Si and alumina / Al / Si. The depth of the hollow in the Al sample, which has native oxide, was measured as 0.5 mu m using a Be-Cu probe under the applied force of 10 mN. The relationship between the applied force and the displacement can be explained by the Hertzian theory. In the case of alumina (20 nm, 50 nm) / Al / Si, the hollows were smaller than those predicted by the Hertzian theory. Cross-sectional observations revealed that the Al layer under alumina was deformed vertically and laterally. It was concluded that the breaking of alumina was induced by the deformation of Al.

Effect of Tl on the electrodeposition behavior of Au was investigated by electrochemical analysis, total-reflection X-ray fluorescene analysis, XRD, glow discharge optical emission spectrometer (GD-OES) and hardness measurement. The deposition rate increased with an increase in the amount of Tl addition to the bath. Tl was co-deposited at the interface between the seed layer and the Au films, as well as in the films. In as-deposited condition, the Tl contained films exhibited higher hardness compared with the Tl-free films, while both of them showed almost the same hardness after annealing. It was suggested that the hardness is correlated with the crystal orientation of the grains.

We attempt to prepare the patterned electrode for the formation of nano particles using electrochemical deposition with the cathode whose surface has nano dot patterns. In particular, we applied electrodeposition of Pt and UV nano imprinting lithography (UV-NIL) to prepare the nano patterned electrode. In order to achieve higher activity, the deposition condition of Pt was optimized using additives such as polyethylene glycol (PEG). The surface activity of the Pt films was affected by molecular weight of PEG. It was revealed that the surface activity of the films deposited with the order of thousands of molecular weight of PEG indicated the highest effective current density among the examined films. The Pt films, which exhibited the highest current density, were adapted to fabricate nano-patterned electrode with 400 nm pith periodic structure using UV-NIL. ©The Electrochemical Society.

Sn-Cu films were electroplated on Cu seed layers of various thicknesses. The velocity of the diffusion of Cu atoms from a seed layer into the electroplated Sn-Cu film was investigated, focusing on the effect of microstructural properties of the film. It was found that the diffusion velocity of Cu from a Cu seed layer into the electroplated Sn-Cu film increased with a decrease in the thickness of the Cu seed layer. Moreover, the film microstructure was influenced by the thickness of the Cu seed layer. When the crystalline quality of the Cu seed layer was inferior, a large lattice mismatch developed at the interface between the electroplated Sn-Cu film and the Cu seed layer. As a result of this lattice mismatch, many lattice defects and stress may exist at the interface between the electroplated Sn-Cu films and the Cu seed layers. Therefore, the lattice mismatch was considered to be related to the high-diffusion velocity of Cu from the Cu seed layer. Furthermore, the high-diffusion velocity of Cu was found to cause whisker formation. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3090179] All rights reserved.

Advanced large scale integrated circuits (LSI) and smart sensor systems require nanoscale interconnection to transmit signals. In this work, an approach to realize multilayer interconnection based on ultraviolet nanoimprint lithography (UV-NIL) technology and copper electroplating is discussed. UV-NIL is a low-cost, mass-production technology. Nanoscale dot array patterns and line array patterns of nickel and copper were formed on a silicon substrate using UV-NIL in combination with electroplating. Imprinted 220 nm hole patterns and 150 nm line patterns were formed on photocurable resin with high dimensional accuracy. Using these resin patterns as a mask layer, 245 urn metal dot and 195 nm metal line array patterns were successfully fabricated by electroplating.

We have developed a precise sub-µm processing method by combining ion implantation and nano-plating. In order to show the applicability of this method, we have fabricated a mask for a Bragg grating, which has a striped gold structure with a height of 1.2 µm and a period of 1.59 µm on a 2-µm thick SiN membrane. We have also confirmed that the mask pattern can be transferred inside a silica glass by ion implantation. It is expected that this result can be utilized for the fabrication of optical communication devices. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.

To realize highly sensitive electrochemical immunoassays, a micro-fabricated three-dimensional (3D) electrode was fabricated and applied to enzyme immuno assay based on production of a redox species. The dimensions of the electrodes are 10 microm in width and 30 microm in height, with 20 microm spacing in between, and the 30 pairs of anode and cathode electrodes made up a single sensor. This structure lead to enhancement of the electrochemical reaction, nearly 100% of trap ratio of redox species. It can be applied to highly sensitive enzyme immuno sensing based on p-aminophenylphosphate (PAPP). Applicability of this technique to the immuno assay for one of the clinical diagnostic marker proteins (alpha-fetoprotein; AFP) from 6 to 500 ng/mL was demonstrated.

It is important to obtain the absolute value of current flowing through each power line on a chip of large-scale integrated (LSI) circuits by measurement because this current on an LSI chip is regarded as conductive noise. We have developed a thin-film magnetic field probe that has spatial resolution high enough to obtain the absolute value of high-frequency power current on an LSI chip. Spatial resolution was enhanced by miniaturizing the shielded loop coil, the detection part of the probe. The outer size of the new coil is 50 x 22 mum. In taking measurements with the new probe over a 60-mum-wide microstrip line used as a device under test (DUT), we obtained a 6-dB decrease point of 40 mum, which indicates the spatial resolution of the probe. This value is comparable to the typical width of power lines on an LSI chip, around 50 mum and is less than half that of our conventional probes, around 90 mum. In measurements with the new probe over an LSI chip, we obtained such a fine magnetic near-field distribution that the magnetic fields generated from the lines on the chip were separated. On-chip decoupling was also confirmed by using the new probe. The new probe enables direct verification of a circuit design for suppressing electromagnetic interference (EMI), while conventional coarse mapping of the magnetic near-field cannot be used to evaluate such conductive noise.

An application of electrodeposited CoNiFeMoC soft magnetic thin films, which have high saturation magnetic flux density and high resistivity, to the magnetic recording head was investigated. Because the ductility of the CoNiFeMoC films was low, the head core using the CoNiFeMoC films was difficult to be prepared without being cracked. The ductility of CoNiFeMoC films was improved by the addition of saccharin in the bath which lowered carbon content of the films. By using such ductility-enhanced CoNiFeMoCS thin films, the structure of the magnetic recording head was successfully fabricated with no cracks.

Cathodic polarization analyses was performed to investigate the shift of the fcc-bcc phase boundary and the change in the bee phase ratio in mixed phase for electroplated CoNiFe films. The electroplating conditions that reduced the ratio of the bee phase in the films were a larger over potential and a smaller cathodic current. The electro-deposition conditions that the fcc-bcc phase boundary shifted to the fcc-rich region were strongly related to an initial deposition rate of Fe atoms. This result is similar to that observed in rapidly quenched CoNiFe. In order to investigate the magnetic moments per atom, film density and Bs were evaluated. The magnetic moments per atom of Fe, Co and Ni were found to be nearly 3.0, 2.0 and 1.0 muB, respectively.

We have developed a Co-Ni-Fe write head with a short yoke length for high-speed recording. By reducing the yoke Length to 9.5 mum, the eddy currents induced in a yoke with a relatively low resistivity (0.2 mu Omegam) were reduced. The head of this short yoke had good write performance for a medium with a coercivity of 400 kA/m (5000 Oe) at frequencies up to 250 MHz (the overwrite less than -30 dB, and nonlinear transition shift less than 7%).

The effect of impurities in CoNiFe films and the performance of CoNiFe pole heads were investigated. Electrodeposition of CoNiFe from a bath containing no sulfur-containing additives (SCAs) produced a pole material with excellent magnetic properties. CoNiFe pole heads generated a strong field of about 10 kOe in a recording medium. These heads did not experience large write instability because of the near-zero magnetostriction of the CoNiFe films. Besides producing good magnetic properties, removal of SCAs from the bath improved corrosion resistance. Moreover, annealing after deposition played an important role in controlling magnetic properties and corrosion resistance. Corrosion resistance was inferior if the film was deposited at a relatively low current density, even when a non-SCA bath was used. However, corrosion resistance of that film was improved by annealing. This improved corrosion resistance suggests that the imperfections associated with adsorption and evolution of hydrogen may play important roles in the corrosion mechanism.

The corrosion resistance of soft magnetic films is an important property to be considered in the manufacture of magnetic devices. We investigated the corrosion behavior of the electrodeposited CoNiFe him with desired soft magnetic properties by varying the crystalline structure and the amount of included sulfur. The corrosion property in 2.5% NaCl solution depends largely on the sulfur content and also on the structure of the film. Although the CoNiFe film contains more than 13 atom % Fe, the film of face-centered to body-centered cubic mixed crystals exhibits a high anticorrosion property because of very small grain size with essentially no sulfur inclusion (<0.1 atom %). (C) 1999 The Electrochemical Society. S0013-4651(98)07-027-X. All rights reserved.

Electrodeposited CoNiFe soft magnetic films with high B_s were investigated for use as head core materials. It was found that a film consisting of an fcc phase structure with low Fe content has low magnetostriction of +2∼+6 × 10^-6. When the film composition was fixed at Co₆₂Ni₁₂Fe₂₆, the operating conditions for obtaining soft magnetic properties were optimized It was found that soft magnetic thin films composed of fine crystals 10-15 nm in diameter were obtained in conditions of low pH (< 3.0) and low current density (< 40 mAcm^-2). In these operating conditions, a current efficiency of less than 80% with hydrogen evolution during the CoNiFe deposition was confirmed to be one of key factors for obtaining soft magnetic CoNiFe films with a suitably high B_s value. A typical Co₆₂Ni₁₂Fe₂₆ film had the following properties. B_s=2.0 T, H_c=1.7 Oe, and λ_s=+4.9×10^-6.

A CoNiFe film with saturation magnetic flux density (Bs) greater than 2.0 tesla (T) has been prepared for the first time as a soft magnetic film; the coercivity (Hc) of the film is less than 160 A/m (2.0 Oe). This success was achieved by formulating a new plating bath and operating conditions to form fine grains. The film has a low Hc of less than 160 A/m, a low saturation magnetostriction (ls) of approximately 10-6, and a high Bs of 2.0-2.1 T. The present invention is expected to contribute to accelerating the development of not only the technology of high-density magnetic recording but also the field of magnetic materials in general.

A newly developed CoNiFe film is investigated from the viewpoint of its application to MR write heads. Film composition is Co65Ni12Fe23, prepared by electroplating to obtain a b.c.c. plus f.c.c. mixed phase at that composition. Films with mixed phases improve soft magnetic properties (B-s is 2.0-2.1 T and the magnetostriction coefficient is +1.8x10(-6) to +7.4x10(-6)) and also show improved corrosion resistance. Performance of a head with a double layer structure of a 0.3 mu m CoNiFe film and a 4.1 mu m NiFe film is investigated, and a short throat height is found to give better overwrite performance.

Magnetic materials are classed as 'soft' if they have a low coercivity (the critical field strength H-c required to flip the direction of magnetization). Soft magnetic materials are a central component of electromagnetic devices such as step motors, magnetic sensors, transformers and magnetic recording heads. Miniaturization of these devices requires materials that can develop higher saturation flux density, B-s, so that the necessary flux densities can be preserved on reducing device dimensions, while simultaneously achieving a low coercivity. Common high-B-s soft magnetic films currently in use are electroplated CoFe-based alloys(1-4), electroplated CoNiFe alloys(5-7), and sputtered Fe-based nanocrystalline(8-11) and FeN films(12-14). Sputtering is not suitable, however, for fabricating the thick films needed in some applications, for which electrochemical methods are preferred. Here we report the electrochemical preparation of a CoNiFe film with a very high value of B-s (2.0-2.1T) and a low coercivity. The favourable properties are achieved by avoiding the need for organic additives in the deposition process, which are typically used to reduce internal stresses. Our films also undergo very small magnetostriction, which is essential to ensure that they are not stressed when an external magnetic field is applied (or conversely, that external stresses do not disrupt the magnetic properties). Our material should find applications in miniaturization of electromechanical devices and in high-density magnetic data storage.

It is indispensable for the development of large scale advanced energy storage devices to control the surface nanostructures of the electrode during charging and discharging operations. In this work, analysis and modeling of the electrodeposition process were carried out from experimental and theoretical approaches to establish the precise methodology to analyze and control the process from single grain nucleation level. As for the electrode material for the large scale energy storage devices, potentiostatic electrodeposition of Zn electrode was conducted in aqueous alkaline solution, and the morphology evolution process, such as formation of mossy structures, is investigated in detail to elucidate its formation mechanism

A 16x16ch Au multielectrode array with a diameter of 10 um and an inter-electrode distance of 100 um was fabricated. Electrochemical measurements using a made-to-order 64 ch multichannel potentiostat revealed that all microelectrodes operated as an individual microelectrode, although their properties varied widely. Polarization of 8x8ch microelectrodes in the array showed an interference of diffusion layer formed on the microelectrodes. The interference was also successfully simulated with a FEM numerical modeling of three-dimensional diffusion problem. The degree of interference during the dynamic polarization of the array could be normalized by the geometry of microelectrode diameter and inter-electrode distance

本年度は「低温焼結型接合に適したナノポーラス材料の確立」を目指して、Au-Ag二元系合金から作製可能な安定性の高いAuナノポーラス構造に注目し、鋳造法及びめっき法を用いてAu-Ag二元系合金を作製し、Auナノポーラス構造の作製をおこなうとともに、Auナノポーラス構造を用いた接合を試みた。その結果、具体的には以下のような結果を研究の成果を得た。
鋳造法を用いたAu-Ag二元系合金では、Au-50mass% Agを作製し、選択溶解によりAuナノポーラス構造の作製を試みた結果、溶解時間や溶液濃度、溶液温度を変えることでナノポーラス構造を変化せることが可能であることを明確にし、10nm以下のリガメントサイズを持つAuナノポーラス構造の作製に成功した。さらに作製したナノポーラス構造を用いて、Cu/CuやAuめっき/Auめっきの接合実験を実施し、接合強度を評価したところ、25 MPa以上のせん断強度を得ることが可能であることが明確になった。
まためっき法を用い検討についても、Au-Ag合金膜を作製し、選択溶解から得られるAuナノポーラス構造の作製検討や粒子の形態制御の検討を進めた。特にチオ尿素を錯化剤として用いたAu-Agを含む溶液の最適電解析出条件の検討を進め、約20 nmの粒サイズのAuナノーポーラス構造の作製に成功した。また、選択溶解前に熱処理を行い、その後に選択溶解を行うことにより、さらに微細な5 nmのナノホールの形成を確認した。鋳造法及びめっき法、それぞれで得られた結果については、ESTC2014（5th Electronics System-Integration Technology Conference、2014.09.16）で発表予定である。
平成26年度以降に計画している表面活性化を使った低温接合実験の前準備として、Auナノポーラスシート構造から粉末状構造を作り、Au-Au同士で200℃以下の低温焼結接合に成功した。今年度、購入した低温・ドライ還元装置を立ち上げて実験評価も順調に行っている。

A molecular analysis system at liquid/solid interface utilizing Surface-enhanced Raman Scattering (SERS) was developed using two kinds of plasmonic sensors, a concentric-circled groove type and transparent substrate with nano-particles made of Au, Ag, and Cu. For application examples, adsorption behavior of hydrazine and hypophosphate as a reducing agent at the Cu/liquid interface in the atomistic level. The decomposition reaction with an electric field for Janus Green B (JGB) as a deposition inhibitor was observed at Au/liquid interface. Molecular structure of lubricant molecules on a Diamond-Like Carbon (DLC) film for hard disk media was successfully measured in the depth resolution of 0.1 nm.