bluuebunny/crossref_metadata_2025 huggingface dataset:
Outgassing Behavior of Organic Spin-on-Glass Modified by Ion Implantation
Authors: Yu Cheng-Hong , Chang Yee-Shyi
Published: October 2002

The difficulty in the use of spin-on-glass (SOG) for multilevel interconnections leads to the requirement of higher-temperature (800–850°C) curing of the material, since the low-temperature annealed SOG may result in a significant amount of moisture during subsequent heat cycles leading to reliability problems. However, the application of an ion implantation method can improve the outgassing behavior of SOG annealed at 425°C. The temperature of the ion implantation treatment is made lower so as to be compatible with aluminum which is used as the conductive material. Ion implantation treatment using P+ (phosphorous) and As+ (arsenic) which are applied to the siloxane-type SOG is proposed in this paper. The thermal desorption analysis from experiments shows that the implanted SOG has a much lower water content and does not have a moisture desorption peak up to 600°C for both P+ and As+ implantations. The combination of the thermal curing and ion implantation treatments is beneficial for reducing the residual moisture content and promoting the thermal stability of SOG films. In addition, the results show that the implanted SOG is more insensitive to moisture absorption than the unimplanted SOG under the condition of 48-h air exposure. This implies that both water reabsorption and desorption performances of SOG can be further improved by ion implantation.
Optimizing Substrate Polymers to Optical Disk Requirements by Computer Simulations
Authors: Bruder Friedrich , Plaetschke Rüdiger , Schmid Helmut
Published: October 2002

The dynamic development of optical devices for the future
blue laser compact disk (CD-) technology calls for a projection
of the usability of the appropriate substrate polymers.
As the new hardware is not yet available, a direct examination
of the substrate polymers is not possible.
Computer simulations may present a useful tool to predict substrate
properties parallel to the development of the hardware components and
prior to the chemical synthesis of polymers.
With methods of polymer physics and computer simulations,
important open questions are worked out.
These are, the birefringence of CDs for different polymer materials,
their mechanical strength and melt flow,
the influence of the pit replication on the optical disk readout-signals
and the influence of water absorption on the dishing of the disk.
An outlook on some recent results on structurally modified polycarbonates
with lower birefringence levels, that might become important
in the near future is given.
Magneto-Optical Detection Using an Optical Phase Shifter in Higher Track Density Land/Groove Recording
Authors: Fukumoto Atsushi , Kai Shin-ichi , Masuhara Shin , Aratani Katsuhisa
Published: October 2002

We report the results of magneto-optical (MO) detection using
an optical phase shifter in land/groove recording. We found that
the MO detection method improves not only readout carrier level
but also cross-talk characteristics against optical errors. Using
this method with a 693-nm wavelength diode laser and a 0.55-NA
objective lens, sufficient readout margins against optical errors
were experimentally obtained at a 3.69-Gbit/in2 areal density,
which yielded a 0.35-µm bit length and a 0.5-µm track pitch.
Recording with a track density 1.4 times higher was achieved by
introducing a 640-nm wavelength diode laser, a 0.7-NA objective
lens, and a 0.258-µm bit length and yielded an areal density of 6.95 Gbit/in2.
Optical Design for a Double Level Rewritable Phase Change Disc
Authors: Bruneau Jean-Michel , Bechevet Bernard , Germain Celine
Published: October 2002

We propose solutions for the design of a two recording level phase change erasable optical disc. The feasibility
of such a medium was examined from various angle: recording possibility, material aspect and readability. Some
particular configurations are believed to prevent level intermodulation.
Resolution Issues in Confocal Magnetooptic Scanning Laser Microscopy
Authors: Nutter Paul W. , Wright C. David
Published: October 2002

The influence of confocal pinhole size on the lateral imaging
resolution in magnetooptic scanning laser microscopes (MO-SLM)
is investigated both theoretically and experimentally.
Various scanning microscope configurations are studied theoretically
using a scalar diffraction, transfer function model.
A surprising theoretical prediction is that for the commonly used
differential detector magnetooptic (MO) microscope, no improvement in lateral
resolution is achieved by the use of a confocal imaging arrangement.
A series of experimental tests measuring the MO step response for
a range of confocal pinhole sizes has been carried out and the
results appear to verify the theoretical predictions.
Reduction of Charge Build-Up with Pulse-Modulated Bias in Pulsed Electron Cyclotron Resonance Plasma
Authors: Maruyama Takahiro , Fujiwara Nobuo , Ogino Satoshi , Miyatake Hiroshi
Published: October 2002

Topography dependent charging is one of the most
significant problems in high-density plasma and low-energy
processing. In this paper, we report on the detailed analysis of
etching characteristics under various pulse modulations of
microwave and rf biases to simultaneously achieve no local side
etch and a high selectivity. Consequently, pulse rf bias in pulse
plasma is very efficient for reducing the notch and charge build-up.
In contrast, continuous rf bias in pulse plasma is not
effective in reducing the charge build-up. In addition, we
discuss the reduction mechanism of notch and charge build-up.
In-situ After-treatment Using Low-energy Dry-etching with a CF4/O2 Gas Mixture to Remove Reactive Ion Etching Damage
Authors: Matsui Miyako , Uchida Fumihiko , Kojima Masayuki , Tokunaga Takafumi , Yamazaki Kazuo , Katsuyama Kiyomi , Arai Hiromasa
Published: October 2002

We have investigated a new method of in-situ after-treatment that
precisely and anisotropically removes dry-etching damage induced by
reactive-ion etching (RIE) of SiO2, especially in self-aligned contact (SAC)
processing, through, low-energy etching in the dry-etching chamber after the
RIE. This in-situ after-treatment with a CF4/Ar gas mixture and with a
CF4/O2 gas mixture were examined. The after-treatment with the CF4/O2 gas
almost completely removed both the chemical damage and the crystalline
damage. On the other hand, although RIE damage could be reduced by after-treatment
with the CF4/Ar gas mixture, severe crystal damage remained.
The after-treatment with the CF4/O2 gas mixture could precisely remove the
surface damage and allowed us to control the surface roughness during
removal of RIE damage.
Vertical Profile Control in Ultrahigh-Aspect-Ratio Contact Hole Etching with 0.05-µm-Diameter Range
Authors: Ikegami Naokatsu , Yabata Atsushi , Liu Guo Lin , Uchida Hidetsugu , Hirashita Norio , Kanamori Jun
Published: October 2002

Vertical processing of 0.05-µm-class SiO2 holes with an aspect ratio around 20 was realized using a dipole-ring-type magnetron reactive-ion-etching system in a mixture of C4F8/O2/Ar gas.
Secondary ion mass spectrometric study of the F and C concentration profiles of the polymer deposited inside the holes in the depth direction revealed that a very small
amount of polymer deposition occurred in this system. This indicates that energetic species reached the hole bottoms with excellent verticality, even in an extremely fine
feature. In contrast, the CHF3/CO process (tapered shape) resulted in an extremely thick polymer and carbonized region on the sidewalls, suggesting the presence of
energetic species sticking to the sidewalls. The effects of energetic species impinging onto the sidewalls and the protection resulting from polymer deposition have been discussed in terms of the etched shape
and F/C depth profile. Vertical incidence of the energetic species into the holes is concluded to be a significant factor in realizing a vertical profile.
Acoustic Wave Propagation at a Fluid-Micropolar Boundary
Authors: Shiuh-Kuang Yang Shiuh-Kuang Yang , Shao-Yi Hsia Shao-Yi Hsia
Published: October 2002

In contrast to a homogeneous isotropic elastic medium with only two elastic constants, a linear elastic micropolar solid is characterized by six independent constants. The solid may consist of particles uniformly distributed in a host matrix. Thus, six different types of wave propagation with four distinct speeds can be found in the dispersion equations. The four distinct speeds are associated with one nondispersively longitudinal displacement wave; one dispersively longitudinal microrotation wave; and two dispersively transverse waves in the presence of couple-stress. In this work, we illustrate the reflected and transmitted fields of an incident acoustic wave propagating at the fluid-micropolar interface. The result is compared to the fluid-isotropic case. It is observed that, due to the mode conversion in the micropolar medium, the micropolar medium should instigate a reducible reflected acoustic wave.
Thermoelectric Properties and Hall Effect of Bi2Te3-xSex Polycrystalline Materials Prepared by a Hot Press Method
Authors: Yashima Isamu , Watanave Hiroshi , Ogisu Takayasu , Tsukuda Ryouma , Sato Susumu
Published: October 2002

Bi2Te3-x
Se
x
(0≦x<1) polycrystalline solids are prepared by a hot press
method and their thermoelectric properties are studied. The samples show
the maximum value of Z = 2.3×10-3 K-1 at x=0.22. The lattice thermal
conductivity is smaller than that of a single crystal. The lattice constant and
power factor decrease upon increasing the selenium substitution while
thermal conductivity decreases for x values up to 0.33 and becomes constant
for x values greater than 0.33.
Magnetic Properties of (Y1-xSmx)2Co17 Compounds
Authors: Maruyama Fumio , Nagai Hiroyuki , Amako Yasushi , Yoshie Hiroshi , Adachi Kengo
Published: October 2002

The influence of Sm atoms on the magnetic properties of
(Y1-x
Sm
x
)2Co17 has been studied by means of NMR and magnetic measurements. The easy direction of magnetization at 4.2 K changes from the c plane for x<0.1 to the c axis for x>0.15.
The NMR study has shown that the change of the magnetic anisotropy is explained by the increased contribution to the magnetic anisotropy from Co atoms. In the analysis
of the 59Co hyperfine fields at each site, we assumed that the Co moments at respective sites have the same magnitude and that the transferred hyperfine field from
the Sm spins is proportional to the Sm concentration.
Recovery of the Ferroelectric Properties of Hydrogen-Damaged Ir/Pb(Zr,Ti)O3/Ir Capacitors by Post Annealing
Authors: Tomoyuki Sakoda Tomoyuki Sakoda , Katsuhiro Aoki Katsuhiro Aoki , Yukio Fukuda Yukio Fukuda
Published: October 2002

In this paper, the recovery of the ferroelectric properties of Ir/Pb(Zr,Ti)O3/Ir thin film capacitors damaged by annealing in a hydrogen ambient has been described. The ferroelectric properties of the capacitors markedly degrade as a result of heat treatment in a
hydrogen ambient at 400°C. These properties can be easily recovered to their initial state by post annealing using a rapid thermal annealing process in an oxygen ambient at 400°C for 1 min.
An Improved Stokes Parameter Method for Determination of the Cell Thickness and Twist Angle of Twisted Nematic Liquid Crystal Cells
Authors: Ying Zhou Ying Zhou , Zhan He Zhan He , Susumu Sato Susumu Sato
Published: October 2002

Based on the method previously proposed by us, an improved Stokes parameter method (ISPM), which is independent of the liquid crystal (LC) molecular alignment direction at the front substrate of the cell, is presented here to determine the cell thickness and twist angle of twisted nematic liquid crystal (TNLC) cells. The function equations of the Stokes parameters with the cell thickness and twist angle are deduced, and the experimental method is introduced. The preliminary experimental results verify the ISPM's validity. This method is very simple basically, only four transmission intensities of the TNLC cell are required to be measured. Furthermore, the theoretical analyses indicate that a high level of accuracy can be obtained by means of this method.
Reflective Bistable Twisted Nematic Liquid Crystal Display
Authors: Xie Zhi-Liang , Kwok Hoi S.
Published: October 2002

A reflective bistable twisted nematic (BTN) liquid crystal display has been
developed. It combines the advantages of a truly reflective display without the rear
polarizer, and the bistable nature of the zero voltage state. It was found experimentally
that switching between the two bistable twist states could be achieved by adjusting the
magnitude of the selection voltage pulse, just like the case in transmittive BTNs. In
demonstrating the reflective BTN, we also show for the first time bistability between
the -36° and 324° twist states.
Reactive Ion Etching Mechanism of RuO2 Thin Films in Oxygen Plasma with the Addition of CF4, Cl2, and N2
Authors: Eung-Jik Lee Eung-Jik Lee , Jin-Woong Kim Jin-Woong Kim , Won-Jong Lee Won-Jong Lee
Published: October 2002

In this study, we thoroughly investigated the reactive ion etching
mechanism of RuO2 film in oxygen plasma with the addition of CF4,
Cl2, and N2. The etch rate of RuO2 was examined as functions of flow
rates of input gases, substrate temperature, DC bias applied to the
substrate, and pressure. The concentrations of the etching species in
the plasma were determined using optical emission spectroscopy (OES)
and a quadrupole mass spectrometer (QMS). The etch products were
determined with a QMS and the etched surface of RuO2 film was
examined with X-ray photoelectron spectroscopy (XPS). RuO4 and
RuO3, which are formed by the reactions between RuO2 film and
oxygen radicals, are the only etch products regardless of the kind of
additive gas. The additive gases (CF4, Cl2, and N2) are not directly
involved in the chemical reaction with the RuO2 film, but they increase
the concentration of oxygen radicals and accordingly, appreciably
increase the etch rate of the RuO2 films. The etch rate is limited by
the formation rate of the etch products, which is enhanced by the
bombardment of energetic ions. Therefore, the etch rate depends not
only on the concentration of oxygen radicals, but also on the flux and
energy of the ions bombarding the film surface. In this study, for the
first time, we introduced the use of the O2/N2 plasma system in RuO2
etching.
Static and Dynamic Erosion Characteristics of High-Temperature Metal-Carbon Composite Materials under High-Flux Plasma Irradiation
Authors: Takamura Shuichi , Yamamoto Koichi , Morita Kenji
Published: October 2002

Static and dynamic erosion characteristics under high-flux plasma irradiation have been examined utilizing an in situ spectroscopic method for high-temperature titanium-carbon composite materials. Clear suppression of erosion of titanium carbide deposited graphite was observed under high-ion flux conditions compared to the conventional ion beam experiments. The dynamic transport of carbon atoms across the multilayered carbide is studied by an analytical approach in the case of rapid diffusion in carbide thin layer. A comparison between theoretical and experimental results of temperature dependencies of erosion behavior gives us an estimation of carbon transport coefficients: segregation and dissolution constants.
Ultrasonic Velocity and Absorption in Binary Solutions of Silicon Dioxide and Water
Authors: Bae Jong-Rim , Yun Seung
Published: October 2002

Ultrasonic velocity and absorption coefficient at 21 MHz as well as
shear viscosity, were measured in an aqueous solution of silicon dioxide
over the temperature range of 5–85°C, and the concentration range of
20 to 40% by weight. The absorption coefficient exhibits maximum
values at about 25°C. The velocity exhibits a maximum value at
approximately 64, 66, 68°C in 40, 30 and 20% concentration solutions,
respectively. The ultrasonic velocity and absorption increase with
concentration at a given temperature. The shear viscosity values
increase with concentration and decrease with temperature for a given
concentration.
Brillouin Scattering of Pressure-Induced Glass Transition in Ethanol and Methanol
Authors: Muhtar Ahart Muhtar Ahart , Fuming Jiang Fuming Jiang , Seiji Kojima Seiji Kojima
Published: October 2002

Brillouin scattering of ethanol and methanol was investigated using a diamond anvil cell up to 3 GPa. The pressure dependences of the frequency shift and half width of the Brillouin components of the longitudinal acoustic modes were determined as a function of pressure. The half width shows the maxima at about 1.5 GPa in both the materials.
Brillouin Scattering in B2O3–Li2O–LiCl Glass
Authors: Yamada Jun-ichi , Shirakawa Yoshiyuki , Iida Takamichi , Matsukawa Mami , Ohtori Norikazu , Umesaki Norimasa
Published: October 2002

Brillouin scattering measurement has been carried out in B2O3–Li2O–LiCl glass. The observed Brillouin frequency shift increases with
the addition of a modifier element (both Li2O and LiCl). However, if the
ratio of B2O3 to the modifier is a constant, Brillouin frequency shift
decreases with increasing LiCl concentration. In order to obtain
additional information on the local structure, Raman scattering and
density measurements have been performed. Raman spectra have been
observed as a distinct peak near 780 cm-1 which shows the formation of
tetrahedrally coordinated boron. By increasing LiCl concentration, the
Raman band near 780 cm-1 decreases, but the band near 806 cm-1
increases. This illustrates the breathing motion of oxygen in a boroxol
ring. This result indicates that LiCl mainly modifies the B2O3 network
without forming tetrahedrally coordinated boron.
   By comparing the glass transition temperature (T
g) obtained from
the temperature dependence of the Brillouin frequency shift with that
from the results of differential scanning calorimetry (DSC) measurement,
it is observed that both the values of T
g almost agree. The concentration
dependence of T
g is discussed in terms of viscosity.
Influence of the Sound Field on the Intensity of Sonoluminescence
Authors: Liming Wang Liming Wang , Hideto Mitome Hideto Mitome , Teruyuki Kozuka Teruyuki Kozuka , Toru Tuziuti Toru Tuziuti
Published: October 2002

Cavitation-field sonoluminescence intensity was measured in correlation with sound pressure and its harmonic and subharmonic component signals generated from a well-defined cavitation field in a distilled-water filled rectangular cell by changing the acoustic frequency and the voltage applied to the transducer. Optics was designed to ensure that all the sonoluminescing positions in the cell were detectable by a photomultiplier tube. The results show that it is the second harmonic component of the sound pressure waveform, rather than the subharmonic one, which gives a reliable indication of the threshold of the cavitation and the onset of the cavitation-field sonoluminescence. The sonoluminescence signal exhibits a linear relationship with the simultaneously measured second harmonic component signal and is likely to originate mainly from the subset of stable cavitation bubbles in the cavitation field.
Development of the Multilayer Alternately Poled Piezoelectric Transformers
Authors: Kanayama Kouichi , Maruko Nobuhiro , Saigoh Hiroaki
Published: October 2002

The structure of piezoelectric transformers were studied to enlarge the output power
capacity. The power parameter m
A
2
2 was proposed to predict the performance of the high-power piezoelectric transformers. In a former report, we proposed a new-structure
piezoelectric transformer named alternately poled piezoelectric transformer (APT). Its step-up
ratio was twice as large as that of the Rosen type transformer, in spite of the single layer
structure. In this study, the APT with 1.5 wavelength resonant mode was modified to increase
the output power capacity and the multilayer structure was utilized to enlarge the step-up ratio.
As a result, both a high step-up ratio of 23 and the output power capacity of 7.1 W were
accomplished under a load of 100 k Ω.
Experimental Investigation of a Piezoelectric Ceramic Transformer Using Radial Vibration of Disks Combined with a Coupling Element
Authors: Tomikawa Katsutoshi Sakurai
Published: October 2002

In this paper a new type of piezoelectric ceramic transformer using radial vibration of disks, combined with a coupling element is proposed.
The specific merit of this piezoelectric ceramic transformer is that its electrical input impedance is effectively reduced by the radial vibration of disks with a high electromechanical coupling factor.
First, the structure of the new piezoelectric ceramic transformer is presented.
Next, the experimental results of the input admittance characteristics, gain of step-up voltage and power transmission efficiency of the piezoelectric ceramic transformer which were measured by varying the length of the coupling element are presented.
The experimental results proved that the newly proposed piezoelectric ceramic transformer possessed a vibration mode that could realize a low input impedance and power transmission with efficiency of not less than 90% for a high-voltage step-up application.
Large Electric Conductance in the Interface Direction of Polar/Nonpolar Double-Layered Hetero-Langmuir-Blodgett Films
Authors: Masahito Kushida Masahito Kushida , Shiro Fujimaki Shiro Fujimaki , Kieko Harada Kieko Harada , Kyoichi Saito Kyoichi Saito , Kazuyuki Sugita Kazuyuki Sugita
Published: October 2002

Aluminum, arachidic acid (C20) multilayered and/or 2-dodecyl-7,7,8,8-tetracyanoquinodimethane (C12TCNQ) multilayered Langmuir-Blodgett (LB) films, and aluminum were deposited successively on a substrate. The electric conductance in the interface direction of the upper-Al/C12TCNQ/C20/under-Al structure, upper-Al/C20/C12TCNQ structure, and other control structures was measured using the four-point probe method. The electric conductance in the interface direction of only the upper-Al/C12TCNQ/C20/under-Al structure with the number of deposited LB layers between 3 and 5 was 10 or 100 times larger than that of the control structures, including aluminum thin films.
An Analysis of Periodic Leaky Surface Acoustic Waveguides Using the Hybrid Finite Element Method
Authors: Koji Hasegawa Koji Hasegawa , Masanori Koshiba Masanori Koshiba
Published: October 2002

A numerical approach based on the hybrid finite element method (HFEM)
is described for the analysis of leaky surface acoustic waves (LSAWs)
in periodic waveguides
with electric-flux leakage into vacuum.
Employing superelements and conventional rectangular elements,
we evaluate a functional corresponding to the entire region:
the substrate region,
the inhomogeneous region with electrodes,
and the vacuum region.
Hence,
in this method,
all the effects of piezoelectric perturbation,
mechanical perturbation, energy storage due to nonradiated bulk waves,
and radiation loss of LSAWs are automatically taken into account.
Computed results for aluminum strip gratings
on a 36° Y–X LiTaO3 substrate
are presented.
The convergence of solutions are investigated in detail
and the dispersion curves and radiation losses of LSAWs are evaluated.
Numerical results show that
the electric-flux leakage into the vacuum
affects the complex wavenumbers,
especially in the higher frequency region over the upper edge
of the stopband.
Piezoelectric Actuator of LiNbO3 with an Integrated Displacement Sensor
Authors: Wakatsuki Noboru , Yokoyama Hideki , Kudo Subaru
Published: October 2002

We proposed a new actuator with an integrated displacement sensor. We examined
the bimorph actuator using an oppositely-polarized LiNbO3 plate. The actuator shows
a spurious transient response to driving step voltage due to two resonances
(fundamental mode: 278 Hz, and secondary mode: 1720 Hz). We obtained an
equivalent circuit model using the input impedance characteristics of the driving
electrode and the sensor electrode. We could analyze the transient response of the
actuator using the equivalent circuit model. Our simulation of the feedback circuit
with an equivalent model showed the possibility of suppressing the ringing of the
fundamental mechanical resonant mode.
Effects of Sample Volume and Frequency on Ultrasonic Power in Solutions on Sonication
Authors: Kojima Yoshihiro , Koda Shinobu , Nomura Hiroyasu
Published: October 2002

Effects of the sample volume and frequency on the decomposition of 5,10,15,20-tetrakis(4-sulfonatophenyl)
porphyrin (H2TPPS4-) were studied at frequencies of 126 and 500 kHz and 1 MHz.
The decomposition of the porphyrin depended on the cell radius and liquid height. The
decomposition ratio, (1-R
TPPS), was expressed by the fractional power law of the sample volume V,
where R
TPPS is defined as the ratio for the absorption of the porphyrin in solution before and after
ultrasonic irradiation. The effect of frequency on the decomposition of the porphyrin was
estimated from the slope of the plot of (1-R
TPPS) versus V for different frequencies. The
decomposition rate decreased with increasing the irradiated frequency.
Accuracy Improvement of Reconstruction in Near-Field Acoustical Holography by Applying Data Extrapolation Method
Authors: Kenji Saijyou Kenji Saijyou , Shigeru Yoshikawa Shigeru Yoshikawa
Published: October 2002

Near-field acoustical holography (NAH) is a non-contacting measurement
method to visualize structural vibrations by means of backward reconstruction.
A relevant data-smoothing process is necessary for the NAH experiments.
We had previously proposed a new data-smoothing method with the aid
of data extrapolation.
In this paper, we report the effectiveness of this proposed
method based on the experimental results.
Furthermore, our data-smoothing method is modified for applications to the
generalized NAH (GENAH).
The experimental results show that the reconstruction error of the
surface velocity by the proposed method is less than one-fifth of
that by the conventional real-space window method for S/N=33 dB.
These results indicate that the prospect of improving the accuracy
of reconstruction in NAH for the quantitative analysis of structural
vibrations is obtained by the proposed method.
Measurement of Group Velocity Variation due to Temperature using Frequency Dependence of Interference Intensity of Acoustic Waves and its Fourier Analysis
Authors: Michio Ohki Michio Ohki , Kohji Toda Kohji Toda
Published: October 2002

A measurement theory of variation in group velocity
using an interference of acoustic waves is proposed,
and an experimental result of a piezoelectric substrate
is discussed, when a variation in temperature causes
the variation in group velocity.
This method utilizes a periodic frequency characteristic
of an acoustic intensity
when two acoustic waves interfere in the substrate.
The periodicity is analyzed by fast Fourier transform (FFT),
and the amplitude and phase of the Fourier components
which have dimensions of time are calculated.
Since the phase shifts
by the variation in group velocity,
the measurement of the former leads to
the precise measurement of the latter.
The interference of acoustic waves is caused
inside an interdigital transducer (IDT)
which is used as a reflector for the wave,
and the interference intensity is measured
using an acoustooptic (AO) interaction.
Generation of Monopole Ultrasonic Pulse from a Circular Source and It's On-axis Pressure Characteristics
Authors: Takasaki Kouji , Imano Kazuhiko , Inoue Hiroshi
Published: October 2002

The cycloid function voltage having no resonant frequency component was applied to a piezo-ceramic circular transducer to generate the monopole ultrasonic pulse. The on-axis pressure
characteristics of the monopole ultrasonic pulse with different pulse widths were observed. It was
found that the onset distance of the decrease in amplitude became shorter as the pulse width increased.
The distance of the onset of decrease in the amplitude of sound is proposed as a practical limit of the
near field for the monopole ultrasonic pulse.
Simulation of Temperature Increase in Tissues for Safety Studies of Ultrasonic Medical Equipment
Authors: Kubota Kazuhiro , Ohdaira Etsuzo , Masuzawa Nobuyoshi , Ide Masao
Published: October 2002

To study the safety of ultrasound, tissue-mimicking phantoms are frequently
used instead of real tissues to evaluate the relationship between tissue and
ultrasound from ultrasonic medical equipment. In this paper, a simulation of
increases in temperature in tissue is described. An increase in temperature for
any phantom and for tissue can be estimated using the measured increase in
temperature of a reference phantom if the absorption coefficient and the
temperature conductivity are known.
A Real-Time Processing System for Pulsation Detection in Neonatal Cranial Ultrasonogram
Authors: Masayuki Fukuzawa Masayuki Fukuzawa , Yoshiki Kitsunezuka Yoshiki Kitsunezuka , andMasayoshi Yamada andMasayoshi Yamada
Published: October 2002

In order to observe artery pulsation in the neonatal cranium at the site of pediatric diagnosis, a real-time processing system was developed for continuous detection and display of artery pulsation, from the moving images of the neonatal cranial ultrasonogram.
The pulsation images were continuously generated by calculating the absolute difference between each pixel value at the two images corresponding to about half a heartbeat interval.
The system was confirmed to process and continuously display at intervals of about 150 ms while capturing the echo images at the video rate of 30 ms, showing that the system performance was good enough to observe the artery pulsation in real-time.
By monitoring the pulsation images continuously redisplayed, the critical conditions of the echo image such as the sway of the ultrasound probe could be easily avoided at the site of diagnosis.
Inspection Method for Contact Condition of Soil on the Surface of Underground Pipe Utilizing Resonance of Transverse Lamb Wave
Authors: Tanigawa Hiroshi , Seno Hiroaki , Watanabe Yoshiaki , Nakajima Koshiro
Published: October 2002

A nondestructive inspection method to estimate the contact condition of soil on the
surface of an underground pipe, utilizing the resonance of a transverse Lamb wave circulating
along the pipe wall is proposed.
The Q factor of the resonance is considered and measured under some contact conditions
by sweeping the vibrating frequency in a 150-mm-inner diameter Fiberglass Reinforced
Plastic Mortar (FRPM) pipe. It is confirmed that the Q factor shows a clear response to the
change in the contact conditions. For example, the Q factor is 8.4 when the pipe is in ideal
contact with the soil plane and goes up to 19.2 when a 100-mm-diameter void is located at the
contact surface of the soil.
The spatial resolution of the proposed inspection method is also measured by moving the
sensing point along the direction of laying the length of the pipe into a 85-mm-diameter void.
The resolution of the proposed method is estimated at about 50 mm.
Observation of Several Types of Simulated Pitting Corrosions by Photoacoustic Imaging
Authors: Hiwatashi Yoichiro , Kumabayashi Tomoyuki , Endoh Haruo , Hoshimiya Tsutomu
Published: October 2002

In this study, the imaging of the simulated pitting corrosions using photoacoustic
microscope (PAM) has been demonstrated. Three types of simulated pittings are
prepared: by pressing metal specimens with a diamond pyramid (Microvickers
indenter), by pressing with a steel ball (a Rockwell indenter) and by drilling. Further,
chemical etching of these specimens is also carried out. Nondestructive measurements
of the simulated pitting corrosions is carried out with PAM. The photoacoustic (PA)
amplitude signal corresponds to the surface area of the hole. Furthermore, the phase
signal ratio and the actual depth change show an excellent agreement.
Observation and Nondestructive Evaluation of Grooved Planes by Photoacoustic Microscopy
Authors: Endoh Haruo , Sugawara Shin-ya , Mukai Ryo , Hiwatashi Yoichiro , Hoshimiya Tsutomu
Published: October 2002

Nondestructive testing (NDT) of grooved metal planes has been demonstrated
using a photoacoustic microscope (PAM). The obtained photoacoustic (PA) amplitude image
and signal distribution across the groove are clearly different from those obtained for the
parallel line defects previously reported. The signal distribution profile shows thermal wave
confinement at groove edges. The PA signal peaks at groove edges caused by thermal wave
confinement indicated the precise position of the vertical walls of the groove edges, which
suggests the feasibility of the application of PAM to NDT of specimens with grooved defects.
Self-Aligned 10-nm Barrier Layer Formation Technology for Fully Self-Aligned Metallization Metal-Oxide-Semiconductor Field-Effect-Transistor
Authors: Matsuhashi Hideki , Gotoh Akio , Lee Chang-Hun , Yokoyama Michio , Masu Kazuya , Tsubouchi Kazuo
Published: October 2002

The technology for self-aligned 10-nm barrier layer formation on self-aligned silicidation
(salicide) n+/p shallow junction has been developed for fully self-aligned metallization metal-oxide-semiconductor field-effect-transistor (FSAM-MOSFET). The features of FSAM-MOSFET are (1)
self-aligned silicidation (salicide) for low Si/TiSi2 contact resistances in source/drain and gate
(S/D&G) regions, (2) self-aligned barrier layer on TiSi2 surface, and (3) selective aluminum
chemical vapor deposition (Al CVD) on the barrier layer surface for low sheet resistances. The
FSAM structure can yield high performance with wide gate width and with localized contacts. For
the self-aligned barrier layer on TiSi2 surface, a low-temperature N2 plasma nitridation has been
developed. It has been experimentally confirmed that (1) aluminum is selectively deposited on the
nitrided layer of TiSi2, (2) the nitrided layer acts as a barrier layer for Al, and (3) this barrier layer
is a 10-nm-thick Ti–Si–N ternary amorphous layer. The combination of salicidation, the self-aligned ultrathin barrier layer formation and selective Al CVD is promising for fabricating a deep-submicron FSAM-MOSFET.
Selective Plasma Etching for High-Aspect-Ratio Oxide Contact Holes
Authors: Kim Yun-Sang , Wei Peter Ta-Chin , Tynan George R. , Robert Charatan Robert Charatan , Dave Hemker Dave Hemker
Published: October 2002

The effects of pressure and CH2F2 percentage on the selectivity of oxide to photoresist (oxide:PR) and on reactive ion etch (RIE) lag in a helicon wave high-density CF4/CH2F2 plasma are reported. Operating the helicon source in high-pressure (20–30 mTorr) fluorocarbon and hydrofluorocarbon plasmas results in highly selective oxide etching. By independently controlling the formation rate of depositing polymer precursors, RIE lag effects can be minimized. Plasma and spectroscopic data suggest a correlation between the polymer deposition rate, high oxide:PR selectivity, and reduced RIE lag. An explanation for the results, based upon operation in a downstream mode combined with collisional sheath effects and isotropic polymer deposition, is proposed.
The New Neutron Powder Diffractometer with a Multi-Detector System for High-Efficiency and High-Resolution Measurements
Authors: Kenji Ohoyama Kenji Ohoyama , Tomonori Kanouchi Tomonori Kanouchi , Keiji Nemoto Keiji Nemoto , Masayoshi Ohashi Masayoshi Ohashi , Tsuyoshi Kajitani Tsuyoshi Kajitani , Yasuo Yamaguchi Yasuo Yamaguchi
Published: October 2002

We describe a multipurpose neutron powder diffractometer for high-efficiency and high-resolution measurements, HERMES, which has been installed at the JRR-3M reactor in Japan Atomic Energy Research Institute. To obtain high-quality data for a short counting time, or with a small sample amount, HERMES has a multi-detector system which consists of 150 3He neutron detectors and simple window type collimation. The best resolution is Δ2θ of 18' and Δd/d of 3 ×10-3, where 2θ and d are scattering-angle and d-spacing, respectively. The duration of an ordinary powder diffraction experiment is 1–5 h under the present conditions in JRR-3M. Some typical results of powder diffraction experiments and performance are given in this paper. We also show a result of 2D intensity mapping of magnetic diffuse scattering from a single crystal of a spin glass material.
High-Density Recording Capability of Five-Layered Phase-Change Optical Disc
Authors: Nakamura Naomasa , Morishita Naoki , Suzuki Katsumi , Yusu Keiichiro , Ichihara Katsutaro , Kuwahara Maho , Hasegawa Hiroshi , Kobori Hiromichi
Published: October 2002

High-density recording capability of the five-layered phase-change disc has been
examined from the viewpoints of optical simulation and disc performance. The optical
simulation showed that the temperature rise in the amorphous state balanced that in the crystal
state for the case when the thickness of the lower protective layer was adjusted from 70 nm to
120 nm. Carrier-to-noise ratio (CNR), overwriting erase ratio and jitter were measured by the
optical recording system using a laser diode with a wavelength of 636 nm and an objective
lens of 0.6 numerical aperture. Track-pitch was fixed at 0.6 µm and bit length was varied at a
linear velocity of 6 m/s. CNR of 52 dB, overwriting erase ratio of more than 35 dB, and
overwriting jitter of less than 10% were obtained on both land and groove at a bit length of
0.34 µm/bit.
Single Crystal of the Pb(Zn1/3Nb2/3)O3–PbTiO3 System Grown by the Vertical Bridgeman Method and Its Characterization
Authors: Shimanuki Senji , Saito Shiroh , Yamashita Yohachi
Published: October 2002

A large single crystal (about 30 mm in diameter by 20 mm long) of the
Pb(Zn1/3Nb2/3)O3–PbTiO3 (PZN–PT) solid solution system was successfully grown
using the vertical Bridgeman method and its properties were investigated. No
defects such as flux inclusions were observed on as-polished {100} plates, except
in a small area near the nucleation point. Further, a domain structure with
striped patterning, and an opaque area were observed in the light yellow plate.
Distribution of the temperature of transition (T
RT) from the ferroelectric
rhombohedral phase to the tetragonal phase was investigated within the {100}
plates. Transition temperatures were found to be scattered in the range of 48°C
to 103°C across the area of these plates. Small rectangular samples poled along
the [001] direction and cut along the [100] direction from (001) plates containing
9.5 to 10 mol% of PbTiO3, and with a transition temperature of T
RT=70–90°C,
exhibited high electromechanical coupling constants (rectangular bar mode, k
33
′>85%) at room temperature.
Effect of a Heavy Collision Partner on Ion Loss from a Radio Frequency Trap
Authors: Yoshiki Moriwaki Yoshiki Moriwaki , Tadao Shimizu Tadao Shimizu
Published: October 2002

We present a new model which represents the mechanism of loss of ions stored in a radio frequency quadrupole trap. We observed the storage time and the temperature of Mg+ ions as a function of the cooling gas (He) pressure in the presence of Kr gas, which is introduced as a heavy collision partner. Our model well reproduces the observation.
The Effects of the Preparation Conditions and Heat-Treatment Conditions of Pt/Ti/SiO2/Si Substrates on the Nucleation and Growth of Pb(Zr,Ti)O3 Films
Authors: Hyo-Jin Nam Hyo-Jin Nam , Hyun-Ho Kim Hyun-Ho Kim , Won-Jong Lee Won-Jong Lee
Published: October 2002

Pb(Zr,Ti)O3 films were deposited using DC magnetron multi-target
reactive sputtering on Pt/Ti/SiO2/Si substrates. The effect of the
substrate on the structure of the deposited film was investigated
because the nucleation of the perovskite PZT film would be largely
affected by the substrate surface conditions. As the thickness of the
Ti underlayer increases and that of the Pt layer decreases, Ti
out-diffusion to the Pt substrate surface through the grain boundary of
the Pt layer is enhanced so that the formation of the perovskite phase
is promoted by facilitating the incorporation of Pb component. At the
same time, the degree of (100) preferred orientation of the perovskite
phase decreases. This change in the preferred orientation of the PZT
film is also observed with decreasing the preparation temperature of the
Pt/Ti layers. The structural phase of the PZT film and the resultant
electrical properties have a sensitive dependence on the thermal history
(such as processing time and environment) of the substrate prior to the
deposition of the PZT film. The heat-treatment in Ar environment
promotes the out-diffusion of Ti and the out-diffused Ti, which is
expected to cover a large area of the PZT surface due to its good
wettability, facilitates the formation of perovskite PZT film. The
heat-treatment in oxygen environment, however, is scarcely effective in
obtaining perovskite-phase PZT films because the out-diffusion of Ti to
the Pt surface is suppressed by titanium oxide formed along the grain
boundaries of the Pt layer and the surface titanium oxide will be
localized only at the grain boundaries of the Pt surface due to poor
wettability of titanium oxide on Pt.
Restoration of Images Obtained from the Scanning Tunneling Microscope
Authors: Masayoshi Tsuchida Masayoshi Tsuchida , Kazuo Tokiwano Kazuo Tokiwano , Hirotaka Hosoi Hirotaka Hosoi , Kazuhisa Sueoka Kazuhisa Sueoka , Norio Ohtomo Norio Ohtomo , Yukio Tanaka Yukio Tanaka , Kōichi Mukasa Kōichi Mukasa
Published: October 2002

A new method for the restoration of images obtained from the scanning tunneling
microscope (STM) is presented.
We regard an image from the STM as a realization of
a stochastic process and assume it to be composed of an
underlying image and noise.
The underlying image consists of smoothly varying gray levels
representing the atomic profiles in the STM image.
We express the underlying variation along an axis in terms of
an “almost-periodic” function.
We can determine the function by applying a recently developed procedure
of data analysis, which consists of resolving the nonlinear least-squares
method using the maximum entropy method of spectral analysis.
This technique is applied to both modeled and actual data.
The present method extracts the underlying image from the corrupted data and
removes the horizontal striping effect due to 1/f
β low-frequency
fluctuation.
Conformations of Long Deoxyribonucleic Acid Molecule on Silicon Surface Observed by Atomic Force Microscopy
Authors: Masanori Ueda Masanori Ueda , Tomoji Kawai Tomoji Kawai , Hiroshi Iwasaki Hiroshi Iwasaki
Published: October 2002

By means of atomic force microscopy (AFM), the conformational structures of the circular double-stranded Deoxyribonucleic Acid (DNA) (2.96 kilobase pairs) on step-controlled silicon surface are studied. The DNA molecules observed on the terrace region maintain the supercoiled structure. On the other hand, the DNA molecules observed on the step-bunched region have a modified higher-order structure. Thus, we clarify that the conformations of long DNA are affected by the surface morphology of the substrate.
Effect of Substrate Potential on Plasma Parameters of Magnetic Multicusp Plasma Source
Authors: Yoshio Ueda Yoshio Ueda , Masahiro Ito Masahiro Ito , Takafumi Yoshikawa Takafumi Yoshikawa , Seiichi Goto Seiichi Goto
Published: October 2002

The effect of substrate potential on plasmas produced in a magnetic multicusp plasma source has been studied experimentally. Plasma parameters such as electron temperature and plasma potential are estimated from electron energy distribution function numerically calculated from probe current-voltage characteristics. For a substrate potential of -150 V with respect to the source chamber, which is much lower than substrate floating potentials, the plasma parameters are not affected by the application of the potential. However, for the case where the substrate is shorted with the source chamber, the high energy component of electrons significantly decreases in comparison with the floating case leading to the reduction of electron temperature. In this case, plasma potential is positive with respect to the substrate to suppress electron loss but its absolute value is only of the order of electron temperature in eV, which is much lower than the potential between the plasma and the substrate in the floating case. This discharge mode could be advantageous in significantly reducing the ion impact energy to the substrate plate.
A Mock-Up Test of a Ceramic-Free Antenna Feeder of the Ion Cyclotron Heating System for Next-Generation Tokamaks
Authors: Moriyama Shinichi , Kimura Haruyuki , Fujii Tsuneyuki , Saigusa Mikio , Arai Hiroyuki
Published: October 2002

We propose a ceramic-free antenna feeder employing a ridged waveguide as a local
support in an ion cyclotron range of frequency (ICRF) antenna for next-generation
tokamaks. A one-quarter scale mock-up model of the all metal waveguide designed for
the ICRF system in the international thermonuclear experimental reactor (ITER) is
fabricated, and electrical characteristics of the model, including the coaxial line-to-waveguide converters are measured. Power reflection coefficient of the model including
the coax-waveguide converter at the input coaxial line is estimated to be less than 15%
when below the cut-off frequency of 107 MHz and less than 3% when above the cut-off
frequency. It is found that this ceramic-free antenna support employing a ridged
waveguide is suitable for the ICRF antenna for next-generation tokamaks.
Population Mechanism of the Excited States of Helium Atoms at a Hollow Cathode in He–Ar Mixture Nanosecond Discharge
Authors: El-koramy Reda A. , Achurbecov Nazer A. , Imenov Kader O.
Published: October 2002

This paper reports results and analysis of a nanosecond pulsed discharge at a hollow cathode in the He–Ar Penning
mixture as a step towards a possible interpretation of the effective mechanism of the recombination process. It has been
concluded that the population of the excited states of atoms during subsequent time intervals has a recombination
period. The limit of this phenomenon and future studies are discussed.
Transmission Electron Microscope Sample Shape Optimization for Energy Dispersive X-Ray Spectroscopy Using the Focused Ion Beam Technique
Authors: Saito Masakazu , Aoyama Takashi , Hashimoto Takahito , Isakozawa Shigeto
Published: October 2002

By utilizing the focused ion beam (FIB) technique, we evaluated signal intensity ratios of analyzed areas and the matrix for energy dispersive X-ray spectroscopy with a transmission electron microscope (TEM-EDX). In the case of conventional FIB samples (H-shape), electrons scattered from the thin film area irradiate the sidewalls of the matrix (Si substrate) under the thin film position and they generate a large number of X-rays. These matrix signals are reduced by making samples as U-shaped and removing the underlying sidewalls. The final matrix (Si) X-ray signal is reduced by 90% compared with the conventional H-shaped samples.
The Effect of Etching Gases on Notching and Charging in High-Density Plasma
Authors: Tabara Suguru
Published: October 2002

A comparison of notching of metal etching in Cl2/BCl3 and HCl plasma
was carried out using a transformer coupled plasma (TCP) etcher. We
observed that notches can be reduced by eliminating BCl3 from the gases for
overetching. Furthermore, the HCl overetch process provides notch-free
profiles with high selectivities. The reduction in the sidewall attack by
heavy ions (e.g., BCl2
+ or BCl3
+) and the scavenging of excess Cl
radicals by H radicals are considered to be possible causes for the reduced
notching in the HCl process. The neutralization of the negatively charged
upper photoresist sidewalls by H+ ions is also thought to be the cause for
the reduction in the electron shading damage and notching.
Improvement of the Measurement Precision in an X-Ray Stress Measurement Method for Very Small Areas on Single Crystals
Authors: Fujii Nobuyuki , Inui Katsunori , Kozaki Shigeru
Published: October 2002

In an X-ray stress measurement method designed for very small areas on single crystals, the following two measures were put into practice to achieve high-precision measurement. (1) The number of measurements of lattice strains was increased. (2) The distance between diffraction spots from a standard sample and a sample for measurement were made as close as possible, and thereby the positions of these spots were measured. As a result, we were able to decrease the measurement error to below ±10 MPa and ±5°.