Search

In this study, we fabricated limiting current‐type oxygen microsensors capable of sensing a wide range of oxygen concentrations. The oxygen microsensors consist of yttria‐stabilized zirconia thin films on spiral Ta2O5 diffusion layers and high‐temperature micro‐hotplates. At temperatures above 575 °C, we observed a clear limiting current that increased proportionally with oxygen concentration between 0.4% and 94%. This wide‐range linearity is attributed to the Knudsen diffusion of the oxygen gas passing through the small gap in the spiral Ta2O5 diffusion layer. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, investigation has been made on the electrical properties of graphene/Al contact, ZnO/Al contact and Al/graphene/ZnO contacts in detail. Al metallization is considered, and it is performed via thermal vacuum coating technique under strict monitoring of the rate of thickness of the metal. Spin coating method and shadow masking are done for depositing fabricated graphene and ZnO on the thin film. Comparative analysis has been made on the parameters like saturation current, Barrier height and ideality factors which are calculated using Schottky barrier height (SBH) method. I–V characteristics are analyzed using the key‐sight B2029A semiconductor parameter analyzer. It is seen that the ZnO/Al contact has more ideality factor nearly 0.059 and exhibits Schottky behavior. Meanwhile, maximum saturation current is obtained for Graphene/Al contact whereas maximum barrier height is for ZnO/Al contact. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Nickel selenide thin films were grown on glass substrates at room temperature using the successive ionic layer adsorption and reaction (SILAR) method. Optical and structural analyses of the thin films were also performed. X‐ray diffraction (XRD), energy dispersive x‐ray analysis (EDAX) and scanning electron microscopy (SEM) were used for structural analysis, and UV–vis spectrometer was used for optical analysis. The XRD results indicate that the NiSe2 thin films had a polycrystalline structure. As a result of the optical analysis, the bandgap value decreased from 2.56 to 2.25 eV as the thickness increased. These results suggest that increasing film thickness improves the crystal structure of NiSe2 thin films. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Active thin film electrochromic or thermochromic coatings have been used in smart windows. However, the current cost of active thin film windows is approximately 10 times that of passive film windows. This paper proposes an inexpensive passive thin metal film for all-season energy savings. The proposed passive thin metal film allows heat to flow preferentially in one direction. Thin metal films attached to glass indoor can absorb solar heat and the solar can radiate the heat to a room and to the glass respectively until thermal equilibrium. Because of the heated metal film against the room, as long as the temperature of the film is higher than that of the room, there is no heat flux from the room to the thin metal film which is called perfect thermal insulation. The 960m2 film was installed in an actual hotel in Japan over 10 years and contributed to reducing the energy cost of air conditioning from 54 million yen to 43 million yen, demonstrating an annual energy savings of 11 million yen (US$0.1 million). This paper briefly describes how the proposed economical passive thin metal film will provide all-season energy savings. [ABSTRACT FROM AUTHOR]

The oxalate-extractable Al (Alo) of weathered Nantai-Imaichi (Nt-IK) tephra sampled at Kiwadajima in Tochigi Prefecture, Japan is more than twice as high as that of weathered Nantai-Shichihonzakura (Nt-SK) tephra. This difference is peculiar because the Nt-IK horizon is directly under the Nt-SK tephra, without a buried A horizon in between, and the Nt-IK compares with the Nt-SK in age. The scanning electron microscopic image of the polished section of the pumice prepared from the Nt-SK tephra indicated the presence of weathered product, which would be allophanic altermorph of the thin bubble-wall glass as determined by energy-dispersive X-ray analyses. The unweathered thick bubble-wall glass was also present in the Nt-SK pumice typically accompanied with the weathered product as a thin film on the periphery. In contrast, the Nt-IK tephra lacks unweathered glass, with almost all glass converted to allophanic materials. One of the reasons for the high Alo value of the Nt-IK tephra compared with the Nt-SK is that the former has almost no unweathered glass whereas the latter has them inside the thick bubble-wall glasses. [ABSTRACT FROM AUTHOR]

Detection of foreign matters and nanoparticles included in industrial and chemical products is an important application target for a sensor system. There is a need to detect a small piece of steel tool chipping or breakage included in the products nondestructively. A recent improvement of the manufacturing system strongly required an inspection of all items in every production process to realize the smart manufacturing system. A thin‐film magnetic field sensor is an impressive candidate for this target as it has an extremely high sensitivity, especially because it is driven by alternating current around hundreds of MHz, and it is also tolerant to a surface normal magnetic field due to its demagnetizing force in the thickness direction. In this study, the sensitivity of a sensor system that was created by applying a 0.3 T normal field to the detection area included in a sensor element and also by using a 400‐MHz high‐frequency driven thin‐film magnetoimpedance sensor was evaluated. An observation of the magnetic domain was also carried out at the same time as the sensitivity evaluation. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

• Development of humidity-controlled spin-coating system using N 2 gas. • Variation of the film thickness in presence or absence of N 2 gas. • Doubled film thickness obtained in high humidity compared to low humidity. Spin coating has been used for various applications, such as the coating of resist solutions in semiconductor processes and the fabrication of functional thin films. By rotating at a high speed, thin films can be formed by centrifugal force. Since the film thickness can be controlled by the number of rotations and time, spin coating is often used for simple experiments at the laboratory. However, in a normal laboratory environment, i.e. not a clean room, temperature and humidity can vary depending on the season, time of day, and weather. In this study, we attempted to fabricate electrochromic WO 3 thin films using a spin coater, which we set up independently, that can control humidity. Compared to the WO 3 thin film deposited directly during the rainy season in Japan, the film thickness was doubled by controlling the humidity, even when deposited under the same spin-coating conditions. The WO 3 thin films prepared by this humidity-controlled process exhibited favorable electrochromic properties. Because, especially in systems containing volatile solvents, it was possible to control the film thickness and function during deposition by controlling the humidity, and the results of this research provide a reference to develop a convenient method for obtaining functional thin films regardless of the weather or season. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic-field angle dependence of critical current densities Jc (H,θ) in commercial YBCO tapes grown by MOCVD and MOD was examined at liquid nitrogen temperatures. We first measured Jc (H,θ) in MOCVD-YBCO tapes at 70 and 77.3K in fields up to 2T using both transport and inductive (the third harmonic voltage) methods and compared the results. It was observed that, in low magnetic fields, the transport measurements gave higher Jc than the inductive ones; however, in high fields they agreed well, which is well explained by the effects of weak links due to low-angle grain boundaries. We then investigated Jc (H,θ) in MOCVD- and MOD-YBCO tapes at 77.3K in fields up to 2T. All the tapes exhibited peaks at H//ab in the shape of Mount Fuji, which shows that small random pinning plays a major role. However, an anisotropic scaling analysis showed that the flux pinning mechanisms in those tapes were different, resulting in distinctive angular behaviors of Jc (H,θ). It is suggested that the difference in the flux pinning mechanisms of the two types of tapes came from the different sizes of point defects originating from the growing processes. [Copyright &y& Elsevier]

Abstract: In order to evaluate the effect of membrane surface properties on the initial stage of biofouling, in the reverse osmosis (RO) membrane process, initial bacterial adhesion and biofilm formation experiments were performed under no filtration condition. In this study, five commercialized polyamide thin-film composite RO membranes (SW30HRLE, SW30HR (Dow FilmTec Co., USA), TM820 (Toray Co., Japan), RE-BE, RE-FE (Woongjin Chemical Co., Korea)) were chosen and their surface properties such as surface charge, roughness, hydrophobicity and surface morphology were measured. For examining initial bacterial adhesion, a flow channel reactor was employed for 3h, while for examining a biofilm formation, the CDC reactor was employed for 48h. Pseudomonas aeruginosa PAO1 tagged with GFP was selected as a model bacterial strain. Major findings in this study indicate that although the initial bacterial cell adhesion in a flow channel reactor indicated more bacterial cells attachment on the membrane surface with higher hydrophobicity, the extent of biofilm grown in CDC reactor for 48h became similar regardless of the difference of the membrane surface properties, indicating that the membrane surface properties become a less important factor affecting the biofilm growth on the membrane surface. This finding will be helpful in improving the understanding of biofouling issue occurring in the real RO membrane system, although practical implication is somewhat limited since this study was performed under no filtration condition. [Copyright &y& Elsevier]

Abstract: Thin-film photovoltaic modules which use the chalcopyrite Cu(In,Ga)(Se,S)2 (CIGS) as the light-absorbing layer have now entered the decisive industrial phase. Companies located mainly in Germany and Japan will produce more than 100 MWp CIGS modules in 2008, demonstrating that the CIGS technology has already achieved a certain maturity. Whereas key features of the technology are already well-optimized, there are several approaches to further improve the productivity of new lines. The ZSW operates a line for 30×30 cm2 modules in which all process steps – from glass cleaning to module encapsulation – are being developed. A major goal of the development is the very fast and efficient transfer of promising new materials and processes from cells to the industrial module level. Therefore, ZSW is focusing on processes like the in-line co-evaporation method for CIS or chemical bath deposition for buffer layers to optimize the junction. We could demonstrate efficiencies close to 18% for small test cells and 14–15% for modules with modified processes. Different cell and material data from optoelectronic measurements and microscopic analysis will be presented in this contribution. [Copyright &y& Elsevier]

Abstract: Efforts of industrial application of Cat-CVD technology are surveyed. Recent movement of industrial implementation is also reviewed by showing examples in Japanese industry. Cat-CVD technology is originally developed as a new tool for fabricating semiconductor devices, however, recently, use of the technology is attempted in various fields such as chemical, mechanical and bio-technical engineering. It is shown that Cat-CVD has high feasibility as a fundamental technology of modern industries. [Copyright &y& Elsevier]

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements. Double thin film method was applied to investigate the seasonal change of the mixing states of single sea-salt aerosols associated with chlorine loss due to the heterogeneous reactions between sea-salt particles and acidic gases. It was revealed that the percentages of both chloride-nitrate mixed particles and sulfate-nitrate ones were larger in wintertime than those in summertime and fraction of chloride-nitrate mixed particles increased with an increase of particle size. Comparison between the size-segregated bulk analysis and the single particle analysis demonstrated that remarkable chloride depletion occurred in coarse particles sampled on May in the former analysis, while chloride depletion in coarse particles was not marked in the latter analysis. The discrepancy attributes to the difference of the sampling time between both analyses because significant change of air mass route occurred during the bulk sampling after completion of the single particle sampling. [ABSTRACT FROM AUTHOR]

Abstract: Radon (222Rn) concentration was measured at indoor workplaces in Japan to estimate effective dose to the public from 222Rn and its progeny. Measurements were made from 2000 to 2003 at 705 sites in four categories of office, factory, school and hospital. Passive type Rn monitors equipped with two sheets of polycarbonate thin films for measuring radon concentrations were installed at observation sites and replaced every 3months to observe seasonal variations in 222Rn concentrations. The range of annual mean 222Rn concentrations for all sites was 1.4–182Bq m−3, with the arithmetic mean and standard deviation were 20.8 and 19.5Bq m−3. Annual mean 222Rn concentration observed at office, factory, school and hospital were 22.6, 10.1, 28.4 and 19.8Bq m−3, respectively. Seasonal variations in 222Rn concentrations at offices, schools and hospitals were similar to those found in dwellings, and variations in factories were similar to those found in outdoor environments. 222Rn concentration observed in every quarter period was found to decrease as follows: school>office>hospital>factory. The average effective dose to the public due to 222Rn was estimated to be 0.41mSv y−1 weighted by the working population. Considering the 222Rn exposure in indoor workplaces, effective dose to the general public is estimated to be in the range from approximately 0.42 to 0.52mSv y−1. [Copyright &y& Elsevier]

R&D of fundamental technologies for superconducting AC Power equipment (Super-ACE project) started as a national project, for a five-year plan since fiscal 2000 by MIT and NEDO. This project is to research and develop the basic technology of super-conductive cable, fault current limiter and transformer. This paper summarizes the research and development of following 2 types FCL. The R&D of the SN transition resistive type superconducting thin film fault current limiter aims to establish large-current/high-voltage technology by arranging films in multi-parallel/series, and increasing the current-carrying capacity through widening the area of the thin film of the current limiting element. The R&D of the reactor for a rectifier-type fault current limiter using coils of superconducting wire of the Ag sheath Bi2223 tape, aiming to apply it to high-voltage systems. [ABSTRACT FROM AUTHOR]

The Institute of Space and Astronautical Science (ISAS) balloon group has been developing and manufacturing plastic balloons made of very thin polyethylene films which can easily reach an altitude of more than 40 km with a payload less than 10 kg since 1991. In order to launch the thin film balloon confidently and easily with the least amount of people, we have developed a new launch method called the packing launch-method. In this method, we pack the uninflated portion of the balloon in a bag. We can ignore the length of a balloon in launching because the packed part of the balloon is extended in the sky after launching, and it is possible to launch a large balloon from a launch field of limited size. The packing launch-method is a revolutionary way of launching high altitude balloons made of thin polyethylene films. [Copyright &y& Elsevier]

Carbon tool steel, SK5 in Japanese Industrial Standard, was used as a substrate for the deposition of carbon film, and the soot-like films showed good field emission properties. Depositions were carried out by heating the substrates at 800, 900 and 1000 °C in a hot-filament reactor under H2–10%CH4 at 30 Torr. Threshold fields were 3, 2.5 and 2.5 V/μm for the samples grown at 800, 900 and 1000 °C, respectively. Minimum emission currents and emission site densities were obtained for films grown at 900 °C. Maximum emission current, 4 mA at 5 V/μm, was obtained for the sample grown at 800 °C. Film morphology also changed with substrate temperature. Nanoclusters were observed in the samples grown at 800 and 900 °C. However, grown at 1000 °C, nanoclusters disappeared, and only ball-like structures over 5-μm diameter were seen. Carbon nanotube and/or fiber structure did not observe for the 800 °C sample. Nanoclusters are considered to improve the electron emission properties of the carbon films. [Copyright &y& Elsevier]

From the practical point of view, conductive film materials that are thin and flexible are chosen as practical shielding materials, and their shielding effect is studied. In the analysis, the concept of equivalent surface resistivity is applied to the FDTD method. The effectiveness of this method in the analysis of absorbed power of the electromagnetic wave in the human body is investigated. The effectiveness of this method for this type of analysis is confirmed. In addition, the shield effect is quantitatively evaluated in terms of the variation of the surface resistivity of the conductive film. It is shown that a resonance phenomenon occurs when the shield effect varies depending on the distance between the human models. It is observed that in such a situation the electromagnetic wave is concentrated in the front surface of illumination so that a large local SAR appears. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(9): 86–92, 2000 [ABSTRACT FROM AUTHOR]

By using stoichiometric, low-resistivity intermetallic compound composed of valve metals, it is expected that anodized capacitors with high heat resistance and high reliability can be realized. We therefore prepared a stoichiometric Al3Zr film by co-sputtering an Al-Zr composite target, and the electrical properties of the Al3Zr anodized capacitor were compared with those of Al3Hf capacitor from the viewpoints of reduction of oxide thickness and heat tolerance. It is shown that Al3Zr anodized film is also a very promising material for high-reliability thin-film capacitors, alongside Al3Hf capacitors. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(7): 1–8, 2000 [ABSTRACT FROM AUTHOR]

It has been shown that rutile-rich TiO2 films with excellent electrical and chemical characteristics can be prepared by deposition on Si surfaces at low temperature, using ionized oxygen gas with an admixture of He gas. The Si surfaces were cleaned by etching with Ar gas before film deposition. We investigated whether the same rutile-rich TiO2 films could be obtained on Si surfaces cleaned by Ar etching if the substrates were cleaned with a gas mixture consisting of H2 or CF4 instead of Ar alone. Etching with only H2 added led to the growth of anatase TiO2 films, but etching with an Ar + H2 + CF4 mixture for the optimum etching time led to the growth of rutile films. This result is attributed to interaction of positively charged SiH or negatively charged SiF with positively charged O2 ion. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(7): 9–13, 2000 [ABSTRACT FROM AUTHOR]

Since the discovery of the new high Tc superconductor, various kinds of film growth techniques have been reported on fabrication of an oxide superconducting film, especially YBCO and BSCCO above liquid nitrogen temperature. All these techniques require the so-called post-growth heat treatment or a heating of the substrate during the deposition to grow an adequate polycrystal which can realize the superconducting state in the oxide. Such a heating process, however, yields some intermediate products at a boundary layer between the starting materials and the substrate, and the products result in degradation of the superconducting property. In this paper, the annealing effect on the growth of YBCO or BSCCO oxide superconducting film and the substrate is investigated by using EDX analysis and SEM examination. To enhance the annealing effect, relatively thin YBCO and BSCCO films are fabricated with the starting materials pasted on substrates, and rather than sputtered thin films used for the analysis. Mg0, A1203, SrTi03, 5 or 8 percent Y stabilized Zr02 (YTZ or YSZ), and so on, are chosen as a substrate. The results show that the heat treatment yields Ba compounds between YBCO and the substrafes and Sr and Bi compounds between BSCCO and the substrates. Since the product boundary layer of the intermediate product is the thinnest, Mg0 substrate can be recommended for YBCO film, and SrTi03 substrate for BSCCO film. [ABSTRACT FROM AUTHOR]

A polyimide film (varnish) on a copper film tends to change in color and to show degradation of the thermal and mechanical properties during the thermal-curing process. The causes of these property changes were investigated by observing the film appearance and analyzing the molecular structure of films and the infrared absorption spectrum. As a result, it was found that copper diffuses in- to the polyimide film during the imidization process, causing the decomposition of the imide-bonds which further causes the changes in color and properties of the film. [ABSTRACT FROM AUTHOR]

To improve the reliability of an electrical signal transmission through a contact, not only the contact resistance, but also the nonlinear characteristic must be evaluated, especially in the presence of a surface film. This method is effective in the separation of the film resistance and the constriction resistance, and the measurement of film thickness. To investigate the distribution of the oxide film thickness, the system was fully automated to measure the film thickness at various points on a sample surface. The measured properties were the contact resistance and the dc current which is one of the nonlinear components and is needed to cancel the rectification characteristic. To form a contact, copper, platinum and nickel wires were used. This paper demonstrates three-dimensionally and statistically the characteristics at various spots on a plane. [ABSTRACT FROM AUTHOR]

Position-sensitive photodetectors detect an illuminated position without using image scanning. A large area detector of dual-axis tetralateral PSD has been fabricated using amorphous silicon for low cost. The effective area of the device was 9.6 × 9.6 mm2, the detection deviation within 2 mm from the center was 0.3 mm and the pulse response time was around 1.5 ms. The resistive divider layer using Pd and Me thin films provided good results. The position-sensitive characteristics were simulated numerically by using Lucovsky's equation and the result was in good agreement with the experimental resuit. The analytical results lead us to the conclusion that in case of two-dimensional dual-axis tetralateral PSD, the nonlinearity in the position coordinate of the measured signal is caused by the introduction of both coordinate components for illuminated position (x0, y0) to each signal potential components at the x or y axis. [ABSTRACT FROM AUTHOR]

A mirror furnace system for annealing of superconducting thin films, which is adapted for the world's longest dropshaft completed at Kamisunagawa, Japan, is described. The system must be designed for completing both melting and solidification processes during a short 10-s microgravity period, and also for withstanding the deceleration of a drop capsule in which the furnace system is Contained. All moving components must be operated so as not to disturb the microgravity environment. A random vibration test for the entire system was carried out before the microgravity experiment, and structural compatibility was verified. The furnace system worked well, and the accumulated number of free falls was 19. Results of annealing of the superconducting material at one gravity and microgravity were compared using scanning electron microscopy and x-ray microanalysis. [ABSTRACT FROM AUTHOR]

A structure with a ribbon-shaped metal thin film on a highly coupled anisotropic piezoelectric substrate acts to concentrate the acoustic wave energy into the region with the thin film. A device making use of the nonlinear interaction of the surface acoustic waves propagating in opposite directions on this Δv/v waveguide is the surface acoustic wave convolver. However, a theoretical analysis on its efficiency is not sufficient. In the present research, the guided wave characteristics of this Δv/v waveguide are derived accurately so that the nonlinear components generated on the waveguide are computed. The generation efficiency of the surface acoustic wave at the second harmonic generated from this mechanism in the direction orthogonal to the waveguide is analyzed theoretically. The conversion efficiency of the split waveguide-type convolver proposed previously by the authors can be derived quantitatively so that the evaluation of the surface acoustic wave nonlinear device becomes possible. [ABSTRACT FROM AUTHOR]

The article reports on the production of copper indium gallium selenide (CIGS) thin film solar cells for photovoltaic (PV) technology by Honda Soltec Co. Ltd. in Japan. The initiative is undertaken to generate efficient energy that power its fuel cell vehicles and factories. Honda uses an undisclosed new circuit material and modified screens to cut the metallization and shade loss.

The article discusses the silicon-on-insulator (SOI) market in Japan. IBM Corp., Sony and Toshiba have launched high-end mobile and entertainment applications of SOI in the Asian market. SOI got its start in Japan in 1978, when Nippon Telegraph and Telephone Corp. developed the separation-by-implanted oxygen (SIMOX) process and gave the first demonstration of an SOI device. With the next generation of ultrathin-film SOI for fully depleted high-speed logic devices at the 65nm node and beyond, the thickness of the top active silicon layer will get down to as little as 200A. Solutions to the challenges of achieving high-volume production of these ultrathin layers currently on track to meet the industry roadmap requirements.

The 12th International Superconductive Electronics Conference (ISEC 09) was held in June 2009 in Fukuoka, Japan. The conference was very successful, with 253 participants from 17 countries. This special issue is a compendium of selected papers based on the technology presented at that meeting. ISEC has established itself as the leading meeting specializing in superconductor-based electronics and has been organized every two years since 1987. This conference provides an opportunity to present the latest developments in superconductive electronics research, and to interact among the world''s experts with maximal interchange between the various topics. The main theme at ISEC 09 was developments in superconductive devices and electronics systems for advanced sensing, medical, communication and information technologies. Technical topics covered at ISEC 09 include: Digital/mixed signal processing RF electronics SQUIDs and their applications Mixers and detectors Thin film materials, junctions and novel devices. Among the 210 presentations, including plenary, oral and poster, only very high quality presentations have been selected for this special issue. Since the success of the conference depends on many invaluable contributions, I must express my appreciation to many individuals and organizations, in no particular order. I would like to thank the Japan Society for the Promotion of Science (JSPS) 146 Committee for co-organization of the conference. I owe a huge debt of gratitude to Akira Fujimaki and the rest of the program committee members for the stimulating conference program. Catherine Foley and Hideo Itozaki both played a prominent part in arranging the special issue as Guest Editors. I would also like to acknowledge the support of JSPS, The Fukuoka Convention and Visitors Bureau, The Murata Science Foundation, Tateisi Science and Technology Foundation, and Kyushu University. Finally, I would like to thank each and every participant at ISEC 09 for making a worthwhile contribution. Your work and your willingness to make this conference a success are indispensable. [ABSTRACT FROM AUTHOR]

The article reports on the plan of Tokyo Electron Ltd. to invest in solar cell equipment with thin-film deposition system in Japan. Chairman Tetsuro Higashi recognizes the need to improve the process associated with technological change to move in the market. He adds that the company will improve its business to grow in the semiconductors industry.

Reports that work at Selete, Japan's semiconductor technology consortium, finds in 2004 that high-k gate dielectric film made of HfSiO[sub x] reduces gate leakage just as well as HfAlO[sub x]. More efficient production of high-k dielectric film through a batch CVD process instead of atomic layer deposition; Comparison of the materials' carrier mobility, threshold voltage and off-current leakage; Implications on solid state technology.