The Japanese public has been assumed to possess a deeply ingrained aversion toward the acquisition of nuclear weapons. We employ a survey experiment to ascertain whether this aversion is unconditional or may erode in the face of hypothetical deterioration in Japan's security situation, and in particular a hypothetical withdrawal of the US security-nuclear umbrella, increased North Korean nuclear weapons testing activities, and movement by South Korea toward the attainment of a nuclear arsenal. We find that the Japanese nuclear aversion may come under stress in the face of such developments. Additionally, we find that the elasticity of Japanese attitudes with respect to the nuclear option in the face of external security deterioration may be associated with an important individual-level demographic characteristic, namely, gender.

Photochromic (PC) ZnO nanoparticles are synthesized for the first time by using a VHF plasma enhanced CVD apparatus. The prepared ZnO film changes from transparent to PC state under UV irradiation; on being subjected to heat treatment, it changes back to transparent state. There is a threshold temperature for attaining the PC phase. The Debye-Waller factor of Zn atoms is specifically large for the PC ZnO. The ZnO nanoparticles contain carbon as impurity. The effects of C-O bonds on the ZnO crystal structure and density of states (DOS) are simulated based on density-functional theory. The results reveal that the crystal structure is slightly distorted and a sufficient DOS for PC light absorption is formed in the band gap.

We report here partially stabilized zirconia (PSZ) matrix deposited with nanocrystalline diamond (NCD) films on its surface as an alternative material for pulverization disk with a potential of substituting high cost synthetic single crystal diamond. The deposition of NCD films on PSZ improved the characterization of the desorption-oxygen from PSZ matrix and enhanced the poor adhesion strength between NCD film and PSZ when N2 was used as doping gas. The results for X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed that with increasing N2 flow rate, nitrogen and desorption-oxygen were incorporated into film. The adhesion test and the pulverization test showed that enhancement in the adhesion strength as well as in the pulverization performance with increasing nitrogen and oxygen concentration in the NCD films. The results proposed to substitute a synthetic single crystal diamond with PSZ by coating nitrogen-doped NCD film.

Properties of p-type μc-Si prepared by Cat-CVD (Catalytic Chemical Vapor Deposition), often called Hot-Wire CVD, are studied for possible application to window layer of a-Si solar cells. Electrical, structural and optical properties are investigated. It is concluded that Cat-CVD p-type μc-Si is a suitable material as a window layer for Cat-CVD a-Si solar cells.

The selection of Preliminary Investigation Areas (PIAs) to be considered in the siting procedure for a Japanese High Level Radioactive Waste (HLW) repository, will require Site-specific Evaluation Factors (SSEF) to be considered. Evaluation of these factors requires a methodology for taking into account various kinds of uncertainties in varied types of literature data. The study described here evaluated the application of Evidential Support Logic (ESL) for this purpose. The approach involves constructing hierarchical process models. Uncertainties are then propagated from the lowest processes, corresponding to data or information, through intermediate processes, to some top level process of interest, such as “assessing the existence of an active fault”. To evaluate the usefulness of ESL a hypothetical site was assessed. The results demonstrate the value of the approach to support decision-making in the selection of PIAs.

Rapid progresses are achieved in catalytic CVD (Cat-CVD), often called hot-wire CVD, in the past 3-years NEDO national project in Japan. Cat-CVD technology presents many advantages in thin-film formation processes; high-efficiency of gas use, large-area deposition, no ion bombardment and low-temperature deposition even below 200°C. All of the elemental techniques for the industrially applicable Cat-CVD apparatuses, such as the suppression of the metal contamination, the precise control of the substrate temperature, the life extension of the catalyzer, 1-m size uniform deposition and the chamber cleaning, have been completely developed. Sophisticatedly designed substrate holder with electrostatic chuck and showerhead equipped with catalyzers are both key technologies for these achievements. High reproducibility for film properties is also obtained by controlling the reaction between high-density radicals and chamber walls. Prototype mass-production apparatus for SiNx passivation films in GaAs devices has been already developed and this will be probably the first application of Cat-CVD in industry. These recent movements appear to promise the drastic revolution in semiconductor and flat-panel display industries by introducing Cat-CVD in very near future.

Large grain-size polycrystalline Si (poly-Si) films are obtained on glass substrate by newly developed catalytic chemical sputtering method at low temperatures around 400 C. Si films are also epitaxially grown on (100) single-crystalline Si substrates. In the method Si films are deposited by the chemical transport of SiH4 species generated by the reaction between solid Si target and catalytically generated H atoms. Efficient deposition is realized using the remarkable difference in the etch rate depending on Si target temperatures. That is, SiH4 species are efficiently generated on cooled Si target by atomic-H etching and deposited on substrates with suppressed etching phenomena by heating. Full-width at half maximum of transverse-optical Raman signals originating from crystalline phase for the obtained poly-Si films is narrower than that for poly-Si prepared by excimer-laser annealing. It was noticeable that the grain size exceeds 1 m for the films with a thickness of about 1 m. Growth mode of poly-Si films especially in the initial stage is remarkably changed with a difference in the substrate material. It was found that formation of seed layer enhances the growth of poly-Si films on glass substrate.

Thermal influence on film preparation in catalytic chemical vapor deposition (Cat-CVD), often called hot-wire CVD, is investigated since heat radiation from catalyzer and thermal transport by introduced gases are one of the dominant factors to determine the film properties. It was found that catalyzer-surface area is a key parameter determining not only the deposition rate but also the thermal influence. “Catalytic platE” instead of the conventional wire was proposed in order to suppress the heat radiation with keeping the catalyzer-surface area. Cat-CVD method employing the catalytic plate is superior to conventional “hot-wirE” CVD method.

Gas-phase and surface reactions of transported species decomposed on the catalyzer were investigated in catalytic CVD (Cat-CVD), often called hot-wire CVD, using a specially designed reactor tube. The phenomena were comparatively studied using H2- or He-diluted SiH4. It turned out that the control of gas flow through the catalyzer between the gas showerhead and the substrate is a key factor to obtain high uniformity in not only the film thickness but also the crystallinity for Si films prepared by Cat-CVD using the gas pressure above about 10 Pa and the gas-flow velocity faster than several m/s.

Feasibility of SiNx passivation films at low substrate temperatures prepared by catalytic chemical vapor deposition (Cat-CVD) is studied for ferroelectric nonvolatile random access memories (FRAMs). SiNx films were prepared at low substrate temperatures of 100 °C, 175 °C and 200 °C using Cat-CVD. Adjusting on flow rate ratio of SiH4/NH3, the refractive index of SiNx film, deposited at 175 °C and 200 °C, measured by ellipsometry is controlled around 2.0. SiNx films, with the refractive index around 2.0, deposited at only 200 °C show the following properties. 1) No oxidation during air exposure for 3 months was observed for the films. 2) Etching rate of the films in buffered HF is 20 nm/min. The dense SiNx film, which is resistive for oxidation in air exposure and dissolution in buffered HF, is prepared at 200 °C and the film is suitable to the passivation of ferroelectric capacitors.

This is to review the present understanding on Cat-CVD (catalytic chemical vapor deposition) or hot wire CVD. Firstly, the deposition mechanism in Cat-CVD process is briefly mentioned along with key issues such as the effect of heat radiation and a method to avoid contamination from the catalyzer. Secondly, the properties of Cat-CVD Si-based thin films such as amorphous silicon (a-Si), polycrystalline silicon (poly-Si) and silicon nitride (SiNx) films are demonstrated, and finally, the feasibility of such films for industrial application is discussed.

We investigated the effects of exposure to active ammonia (NH3) gas generated by catalytic chemical vapor deposition (Cat-CVD) apparatus on ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) capacitors. It is very important to know these effects in order to apply Cat-CVD SiNx films to passivation films for ferroelectric FRAMs. The exposure to active NH3 was carried out for PZT film capacitors with two types of bottom electrodes on Si wafer at various substrate temperatures. The capacitor with Pt/IrO2 bottom electrode peeled off from substrate during exposure over 200°C. On the other hand, the ferroelectricity of the capacitors with IrO2 bottom electrodes gradually degraded from 200°C to 300°C. As a result, it is found that no degradation of the ferroelectricity is detected for exposure below 200°C. It is concluded that the Cat-CVD method is a promising candidate for preparation of the SiNx passivation film on ferroelectrics, since it is a low stressed film with low hydrogen content.