Yoshiharu Ozaki

Ultrafine electroceramic powder preparation from metal alkoxides

Abstract An utilization of metal alkoxide is one of the high potential methods for preparing electroceramic powders. The advantage of powder preparation from metal alkoxides is that the ultrafine, monodispersive and compositionally homogenous powder is obtained easily by a simple hydrolysis reaction. Powder preparations from metal alkoxides are discussed in comparison with other conventional techniques.

Transparent magnetic fluid: preparation of YIG ultrafine particles

Abstract In order to prepare transparent magnetic fluid, yttrium iron garnet ultrafine particles ranging in size from 10 through 30 nm are synthesized by hydrolysis of metal alkoxides. Differential thermal analysis, X-ray diffraction analysis, electron micrography and magnetization measurements are carried out on these particles to investigate the calcination condition and particle sizes.

Pressure Effects on the Eutectic Temperature of the Sn-Zn, Sn-Pb, Sn-Bi and Cd-Zn Systems

The pressure dependences of the eutectic temperature in systems Cd-Zn, Sn-Zn, Sn-Pb and Sn-Bi are investigated up to 35 kbars. In the system Cd-Zn, Sn-Zn and Sn-Pb it shows monotonous increase with pressure. But in the system Sn-Pb the simple eutectic relation vanishes. In the system Sn-Bi it shows a minimum. The melting curves of Cd, Zn, Sn, Pb and Bi are also determined up to 35 kbars. These results are compared with those of Kennedy and Butuzov. The observed and calculated initial slopes of the pure metals and the eutectic mixtures are discussed on the basis of the thermodynamic representation of the pure and binary system. The agreement of both is good. Especially it is noticeable that the pressure effect on the eutectic temperature is smaller than that in the pure end members.

MOS C-t Evaluation of Reactive Ion Etched Silicon Substrate

The distribution and electrical activity of damage in Si substrates created by reactive ion etching(RIE) in CF4+H2 using a metal contamination free chamber was studied by MOS C-t measurement. RIE damage is divided into primary and secondary damage. Primary damage is caused by the penetration of carbon generated in the decomposition of reactive gas, and restricted to the region from the top surface to a depth of 3000 A. Secondary damage is extended to more than a few µm in depth, although its intensity is lower than primary damage. It is also shown that electrical activity of secondary damage is affected by the original defects in the Si substrate.

Fundamentals of Superfine Particles

Fine particles with a diameter of anything from 1 to 100 nm are commonly known as superfine particles. Superfine particles may, however, constitute a completely new form of matter which exhibits patterns of behavior quite different from those of the substance’s corresponding solid form.

Construction of a New Type X-ray Diffraction Camera for High Pressure Studies and Its Application to the Measurement of Compressibility of β-SiC

This report contains a new apparatus for x-ray diffraction study at very high pressure and the measurement of compressibility of β-SiC. The x-ray camera is based on a Debye-Scherrer type geometry and Mo Kα radiation is used. The point is that the x-ray tube and camera are oscillated synchronously around the pressurized sample. This is useful for obtaining clearer diffraction pattern and for doing single crystal analysis at very high pressure. Using the apparatus, the effect of pressure up to 170 kbars was measured on the lattice parameter of β-SiC. The determind compressibility K=4.8×10-7/bar of β-SiC showed no significant influence of pressure. From this result, Grunneisens constant γ=0.78 was calculated.

Light absorption spectra of YIG ultrafine particles prepared by alkoxide method

Quartz, glass plate samples dispersed with YIG ultrafine particles about 30 nm in mean dimension were prepared through synthesis by the alkoxide method. Using these samples, the light absorption spectra of the YIG ultrafine particles were measured from the wavelength /spl lambda/=450 nm up to 1800 nm. The peak of the spectra of the YIG ultrafine particles around /spl lambda/=600 nm is shifted to a lower wavelength, while the peak around /spl lambda/=900 nm is shifted to a higher wavelength compared with those of bulk YIG. In addition, the latter peak broadens. >

Effect of plasma polymerization film on reducing damage of reactive ion etched silicon substrates with CHF3+O2 plasmas

The damage generated in reactive ion etched Si using CHF3 added with O2 is studied using a metal-contamination-free reactor. The measurements of the photoconductive decay curve on the etched Si substrates indicate that carrier recombination lifetime decreases as the flow rate of oxygen increases. Physical analysis x-ray photoelectron spectroscopy and secondary ion mass spectrometry show that plasma polymerized film consisting of carbon and fluorine can be seen on the etched Si substrate in the low oxygen flow rate region. The thickness of the film depends inversely on the oxygen flow rate. It becomes clear that thick plasma polymerization film protects the substrate from ion bombardment that results in damage.

Applications of Superfine Particles

As more is discovered about the properties of superfine particles, their potential industrial applications look increasingly promising. Applications such as sensors and magnetic tape, however, are still in their infancy. There is a good deal of potential for applications in the field of materials, especially sintered materials: in this area, materials made from superfine particles outperform the others, and their economic properties make them extremely useful. At present, however, these applications are still at the basic research stage.

ArF Excimer Laser Projection Lithography Using Partially Achromatized Lens System

To study the feasibility of ArF excimer laser lithography, four prototype projection lenses have been designed-a monochromatic lens, an achromatic lens with separate elements, an achromatic lens including cemented elements, and a partially achromatized lens. From the viewpoint of the current technology limit of bandwidth narrowing of ArF excimer laser and accuracy of optical surface fabrication, the partially achromatized lens is found to offer the best solution. 0.18-µm resolution is confirmed using the fabricated prototype lens combined with the 10-pm bandwidth laser and Ag/Se-Ge inorganic resist. Quarter-micron lines-and-spaces pattern is obtained using a tri-layer resist system.