bluuebunny/crossref_metadata_2025 huggingface dataset:
ZnO Thin Films Prepared by Ion-Assisted Deposition Methods
Authors: Miyamoto Kazuhiro , Yoshida Makoto , Toyotama Hideki , Onari Seinosuke , Arai Toshihiro
Published: February 2005

Transparent conducting ZnO films were prepared by an ion-assisted deposition method. The glass substrate was irradiated with Ar ions during deposition of amorphous films and the c-axis-oriented ZnO film with the lowest resistivity is obtained when the growing film is irradiated with Ar plasma. Optical emission lines due to Ar, Zn2, Zn and O of neutral species were detected. In particular, the ratio of emission line intensity O(777 nm)/Zn(635 nm) is closely related with film properties. The control of plasma conditions by the check of the emission line intensity provides a method of obtaining a high-quality transparent conducting ZnO film.
Physical Properties of Tungsten Oxide Films Deposited by a Reactive Sputtering Method
Authors: Kazuhiro Kaneda Kazuhiro Kaneda , Shigeo Suzuki Shigeo Suzuki
Published: February 2005

Tungsten oxide films were deposited in ambient gas (Ar+O2) by a reactive sputtering method, and their physical properties as an X-ray mask absorber were investigated. The density, stress and structure of the films strongly depend upon the sputtering condition, especially on the total working pressure and the oxygen partial pressure. Smooth tungsten oxide films were deposited in the range of 11∼18 mTorr total working pressure and in the oxygen partial pressure of 8.3% and their density was about 13.5 g/cm3. Pressure dependence of the stress of tungsten oxide films was much smaller than that of tungsten films. The stress-free films of tungsten oxide had no fibrous structure and their surface and cross section were smooth.
Hypervelocity Accelerators with Electro-Thermo-Chemical Reaction
Authors: Kazunari Ikuta Kazunari Ikuta
Published: February 2005

A novel kind of electro-thermo-chemical (ETC) launcher for the acceleration of multikilogram-size projectiles to hypervelocity is proposed. The novel launcher concept utilizes the hot hydrogen gas generated by the chemical interaction between water and aluminum in order to accelerate the projectiles to a thermal velocity close to that of the light gas. This interaction is triggered by the Joule heating of the aluminum wire in water. Two possible designs for the accelerator concept are considered in detail. Further acceleration of the projectile near the muzzle is also discussed.
Detection of Electron Energy Distribution Function by Finite Impulse Response Filter
Authors: Kimura Takashi , Akihiko Yoneya Akihiko Yoneya , Kazuyuki Ohe Kazuyuki Ohe
Published: February 2005

The electron energy distribution function (EEDF) is calculated from digitized probe current-voltage characteristics by using a finite impulse response (FIR) filter, in which filter horizon and cutoff frequency are flexibly chosen. Good agreement between the measured EEDF and the theoretical one is obtained in application of the filter to a He positive column.
Ion Energy Distribution of 13.56 MHz rf Glow Discharge in a Planar System Cathode
Authors: Toru Otsubo Toru Otsubo , Kazuhiro Ohara Kazuhiro Ohara
Published: February 2005

The ion energy distribution of 13.56 MHz rf glow discharges in a cathode has been measured by an ion energy analyzer (IEA). In the cathode, it is necessary to decrease the measurement variation with the rf voltage. The measurement variation could be decreased by increasing the distance between the cathode electrode and the IEA to calculate the motion of ions in the rf electric field.
The relationship between the ion energy distribution and the applied rf excitation voltage on the cathode has been investigated in this system. The average ion energy depends on the selfbiased dc voltage. The maximum ion energy depends on the value added to one-half of the peak-to-peak rf excitation voltage and the self-biased dc voltage.
NIJI-III Compact Superconducting Electron Storage Ring
Authors: Takada Hiroshi , Tsutsui Yasumitsu , Emura Katsuji , Miura Fujio , Suzawa Chizuru , Masuda Takato , Okazaki Toru , Keishi Tomohiro , Tomimasu Yoshikado Hosoda
Published: February 2005

The NIJI-III is a compact superconducting electron storage ring for industrial applications. Features of the ring include four strongly curved large-bore superconducting bending magnets utilizing quadrupole coils with a circular cross section surrounded by an air core and a cold bore. The circumference of the ring is 15.54 m with a critical wavelength of 13 Å. Development of the NIJI-III is near completion. This report examines the design and performance of the NIJI-III.
Storage and Lifetime Measurements of Multiply Charged Ions Produced by Synchrotron Radiation
Authors: Sakurai Makoto , Sekioka Tsuguhisa , Kimura Masahiro , Niizeki Takashi , Hirayama Takato , Terasawa Michitaka , Yamaoka Hitoshi , Awaya Yohko , Yoda Jun , Ogata Atsushi , Ohtani Shunsuke
Published: February 2005

Multiply charged ions of rare gases were produced through photoionization, using white synchrotron radiation from the accumulation ring of TRISTAN, and the ions were confined in an rf trap. Charge state distribution and lifetime of the stored ions were measured by time-of-flight detection. Confinement of Xe6+-Xe8+ was exhibited with the storage lifetime of several ms, which is limited by the high background pressure needed to accumulate sufficient ion intensity.
2D and 1H Nuclear Magnetic Resonance Study of Deuterated Amorphous Silicon and Partially Deuterated Hydrogenated Amorphous Silicon
Authors: Hayashi Shigenobu , Hayamizu Kikuko , Mashima Satoshi , Suzuki Atsushi , Mcelheny Peter J. , Yamasaki Satoshi , Matsuda Akihisa
Published: February 2005

Bonding states and spatial distributions of deuterons and hydrogens in deuterated amorphous silicon and partially deuterated hydrogenated amorphous silicon have been studied by means of 2D and 1H nuclear magnetic resonances (NMR). Four kinds of deuteron line shapes are observed, corresponding to different bonding states: SiD and Si(H, D)2 in a rigid state, Si(H, D)3 in a freely rotating state, Si(H, D)
n
(n=1, 2, and 3) in a constrained mobile state, and D2 molecules in a freely mobile state. The relative intensities of the four states depend on the deposition conditions. The NMR results demonstrate that hydrogens and deuterons do not distribute randomly. The deuterons preferentially locate near the microvoids.
Photoluminescence in ZnSe:Te Prepared by Solution Growth
Authors: Araki Hiroyuki , Kanie Hisashi , Yoshida Iwao , Sano Masatoshi , Masaharu Aoki Masaharu Aoki
Published: February 2005

ZnSe:Te crystals with different Te concentrations were grown from solution using Sb2Se3-Sb2Te3 and Se-Te as solvents, and their photoluminescence properties were investigated. The emission in the ZnSe:Te samples was composed of three bands located at 2.70 eV (TA), 2.50 eV (TB) and 2.35 eV (TC), the relative intensities of which depended on the sample temperature. The energy position of all three bands was independent of the Te concentration. For the Te concentrations of 0.02%, 1.96% and 9.4%, the dominant band was the TA band, the TB band and the TC band, respectively. We attributed the TA band to the emission of excitons bound to the nearest-neighbor Te-Te pairs (Te2). The TB band was tentatively attributed to excitons bound to the Te3 centers, and the TC band to the Te
n
centers (n≥3).
Soft X-Ray Emission Spectroscopy (SXES) Study of the Valence Band Electronic Structure of a Au-Si Alloy
Authors: Watabe Hirokuni , Iwami Motohiro , Hirai Masaaki , Kusaka Masahiko , Nakamura Hatsuo
Published: February 2005

The Si L2,3 valence band (VB) spectrum for the Au0.67Si0.33 alloy was first studied using the soft X-ray emission spectroscopy (SXES) technique under electron beam irradiation. A clear modification was observed in the Si L2,3 valence band spectrum for the Au-Si alloy of that for a Si Single crystal, which made it possible for us to discuss the Si s VB density of state (DOS). It is concluded that a significant amount of the Si(3s) originated electronic state is included in the upper half of the VB-DOS of the Au-Si alloy due to Au-Si bond formation.
Deep-Level Transient Spectroscopy Spectra of Drain Current of Si-Implanted GaAs Metal-Semiconductor Field-Effect Transistors Having Large and Small Low-Frequency Oscillations
Authors: Saito Yasuyuki , Suga Toru , Inoue Kazuhiko , Tatsuro Mitani Tatsuro Mitani , Yutaka Tomizawa Yutaka Tomizawa
Published: February 2005

We report on the drain-current (Id) Deep-level transient s-pectroscopy (DLTS) spectra of Si-implanted metal-semiconductor field effect transistors (MESFETs) with strong or weak Id low-frequency oscillations (LFOs) under the condition of high drain voltages (3 V-7 V). We found no distinguishing features directly related to the Id-LFO in these spectra having large peaks characteristic of the DLTS spectrum. These results imply that deep centers in the MESFET channel layer are not the direct origin of the Id-LFO.
Zinc Diffusion in Al0.3Ga0.7As Grown on Si Substrate
Authors: Sakai Shiro , Terauchi Youji , Wada Naoki , Shintani Yoshihiro
Published: February 2005

Zinc is diffused into Al0.3Ga0.7As grown on a Si substrate by a closed method using ZnAs2 as a source. The diffusion coefficient in Al0.3Ga0.7As on Si is found to be larger than that in the same layer which is grown on a GaAs substrate. The effective diffusion coefficient is related to the defect density in AlGaAs and the diffusion depth. A simple model shows that the diffusion coefficient along the dislocation is about 5 times larger than that in the dislocation-free AlGaAs.
YBa2Cu3O7-δ Angle Grain Boundary Junction on Si Bicrystal Substrate
Authors: Chen* Jian , Yamashita Tsutomu , Suzuki Hajime , Nakajima Kensuke , Kurosawa Hideyuki , Mutoh Yoshiharu , Hirotsu Yoshihiko , Myoren Hiroaki , Osaka Yukio
Published: February 2005

Si bicrystal substrates with angle grain boundaries (AGB) have been fabricated for the first time by a diffusion bonding technique using the hot-press method. YBa2Cu3O7-δ (YBCO) epitaxial thin films are grown on the Si bicrystal substrates with yttria (Y2O3) and yttria-stabilized zirconia (YSZ) buffer layers by rf magnetron sputtering. The properties of bridge-type junctions patterned by excimer laser have been studied from 4.2 K to 77 K and by microwave irradiation. It is found that the critical current density of the AGB junction (J
c
A) is always less than that of either bridge made on single-crystal grains (J
c
G). The effects of the temperature and microwave radiation show that the properties of the bridges on the grains are limited by flux creep. In contrast, the properties of the AGB junction with the angle larger than 10° show the Josephson effect.
Analysis of Modulation Characteristics of Self-Terminating Metal Vapor Lasers
Authors: Hiroshi Taniguchi Hiroshi Taniguchi , Shinji Tanosaki Shinji Tanosaki
Published: February 2005

Analyses with a small-signal approximation on static and modulation characteristics of self-terminating metal vapor lasers are presented based on the rate equations, whereby physically well-defined solutions are obtained. The dynamic responses with an exact analysis of relaxation oscillations in self-terminating metal vapor lasers are also found to be in agreement with those of the small-signal analysis. It is found from both the small-signal and the dynamic response analyses that the modulation characteristics in the decay rate of the cavity exhibit a wider dynamic range on the modulation frequency than that in the excitation rate.
In Situ Microscopic Observations of Melting of Thin Si Film Induced by CW Ar-Ion Laser Oscillating in Various Modes
Authors: Masayoshi Yamada Masayoshi Yamada
Published: February 2005

The melting of thin Si film induced by irradiation from a focused beam of a CW Ar-ion laser oscillating in various modes is directly observed using an optical microscope. It is found that as the laser power is increased, liquid spots first appear, subsequently, a mixture region in which solid filaments fluctuating in time and space coexist with liquid is formed, and finally a uniformly molten region appears at the center of the solid-liquid mixture region. The shapes of the mixture and uniformly molten regions are shown to be strongly influenced by the laser power and/or mode, that is, by the laser intensity profile. It is confirmed that the TEM10+TEM01-like mode gives a molten shape suitable for recrystallizing Si films, compared with the TEM00 and TEM02 modes. The size and fluctuation of solid filaments in the mixture region are discussed.
Frequency-Multiplex Logic Gate Using a Saturable Dye Absorber
Authors: Takehiko Hidaka Takehiko Hidaka , Yoshiharu Hatano Yoshiharu Hatano
Published: February 2005

An experimental result of the frequency-muitiplex logic gate for optical computing is given using a saturable dye absorber.
Defect Production in Phosphorus Ion-Implanted SiO2(43 nm)/Si Studied by a Variable-Energy Positron Beam
Authors: Uedono Akira , Wei Long , Dosho Chisei , Kondo Hitoshi , Tanigawa Shoichiro , Sugiura Jun , Ogasawara Makoto
Published: February 2005

Vacancy-type defects in 150-keV P+-implanted SiO2 (43 nm)/Si(100) specimens were studied by a variable-energy positron beam. The results show that the damaged layer induced by P+-implantation extends far beyond the stopping range of phosphorus ions. From isochronal annealing experiments, it was found that oxygen atoms recoiled from the SiO2 layer into the Si substrate, forming stable oxygen-vacancy complexes in the substrate near the interface. The final recovery of vacancy-type defects was observed at 1200°C.
Magnetostatic Spin Waves in Sputtered Ferromagnetic Films with Perpendicular Anisotropy: CoCr
Authors: Yoshihara Akira , Haneda Yoichi , Ouchi Yutaka Shimada
Published: February 2005

Thermally excited spin waves in a sputtered magnetic slab with perpendicular anisotropy are discussed within a framework of the magnetostatic approximation. Light scattering from the spin waves is also discussed. The spin waves in sputtered CoCr films (12∼15 at.% of Cr and thicknesses up to ∼1 µm) are studied by means of Brillouin scattering in external magnetic fields up to 3.5 kOe. The magnetic constants of the initial ∼500 A-thick growth layer, which exhibits soft magnetic characteristics, are determined. As the perpendicular anisotropy which is dependent on the film thickness is increased, the peak width rapidly increases, making the observation of the spin wave scattering very difficult. The effectiveness of the Brillouin scattering technique for studying films with perpendicular anisotropy is discussed.
1.55 µm Gain in a Short Er3+-doped Zirconium Fluoride Glass Fiber
Authors: Kim Myong-Wook , Cho Woon-Jo , Jae-Cheol Jo Jae-Cheol Jo , Sang-Sam Choi Sang-Sam Choi
Published: February 2005

1.55 µm gain was measured in a 28 mm long zirconium fluoride glass single-mode fiber which was pumped with a 514.5 nm argon ion laser.
Formation of Decagonal Quasicrystal in the Al-Pd-Mn System and Its Structure
Authors: Hiraga Kenji , Sun Wei , Lincoln Francis John , Kaneko Michiyo , Matsuo Yoshie
Published: February 2005

Formation of a decagonal quasicrystal in Al70Pd30-x
Mn
x
alloys (x=8-20) and its structure were examined by X-ray powder diffraction, electron diffraction and high-resolution electron microscopy. The decagonal quasicrystal is formed as a coexisting phase with an icosahedral phase in the composition range of x=10-15, and as a single phase at a composition of x about 20. The structure of the decagonal phase is a mixture of decagonal quasicrystalline regions with some linear phason strain and microcrystalline regions. We propose that the structure of Al-Pd-Mn decagonal quasicrystal may be interpreted as a tiling formed by atom cluster linkages, which are different to those reported in Al-Ni-Co and Al-Cu-Co decagonal quasicrystals.
Crystallographic and Magnetic Properties of Fe/Au(001) and Fe/Au(111) Superlattice Films
Authors: Tetsuo Okuyama Tetsuo Okuyama
Published: February 2005

On Au buffer layers with (001) and (111) planes, Fe/Au superlattice films were prepared by ultrahigh vacuum evaporation. Prior to investigation of Fe/Au superlattices, the structure of Au buffer layers, which significantly influences the structure of superlattices, was studied. The epitaxial growth of Fe(001)/Au(001) layers on a Au(001) buffer layer and that of Fe(110)/Au(111) layers on a Au(111) layer were confirmed by X-ray diffraction and reflection high-energy electron diffraction (RHEED). The films with the two stacking orientations have considerably different surface magnetic anisotropies.
Stress Relaxation in Reactively Sputter-Deposited TiOxNy Films
Authors: Ping Jin Ping Jin , Shigeo Maruno Shigeo Maruno
Published: February 2005

Internal stress in TiO
x
N
y
films sputter-deposited on negatively biased silicon wafers in an Ar-N2-O2 gas mixture was measured by a substrate deflection method. X-ray diffraction (XRD), Auger electron spectroscopy (AES) and field emission scanning electron microscopy (FE-SEM) were also employed for studying structural features of the films. TiN films deposited under an oxygen-free condition have high compressive stress (7.8 GPa for bias 90 V), and the compressive stress in TiO
x
N
y
films decreases markedly with increasing oxygen concentration and becomes slightly tensile at an oxygen flow ratio of more than 1%. It is suggested that the relaxation of the compressive stress is due to the decrease in the lattice parameter caused by substituting nitrogen atoms with oxygen ones and the formation of an amorphous phase in the TiO
x
N
y
films.
Misorientation, Inhomogeneous Lattice Distortion and Strain of InP Grown on Si by Metalorganic Chemical Vapor Deposition
Authors: Tran C. A. , Masut R. A. , P. Cova P. Cova , J. L. Brebner J. L. Brebner
Published: February 2005

Inhomogeneous lattice deformation, misorientation and strain of InP epitaxial layers grown on Si substrates by an MOCVD two-step method are obtained from high resolution X-ray diffraction measurements. The InP films were grown simultaneously on Si (001) and on Si (001) misoriented 3° towards [110]. In the latter, we observe a tilt of the InP [001] axis of 0.1° respect to the Si [001] in the direction of the substrate normal, and the coexistence of weakly and strongly strained domains. The misorientation of the substrate surface from (001) planes results in an uneven distribution of 60° dislocations which gives rise to an extra component of the Burgers vectors perpendicular to the interface causing the observed tilt. The local stress perpendicular to the interface, thus generated explains the existence of the strongly strained domains.
Undoped GaSb Grown on the Structure of In0.3Ga0.7As/GaAs Strain Layer Superlattice by MOCVD
Authors: Juang F. S. , Y. K. Su Y. K. Su , N. Y. Li N. Y. Li
Published: February 2005

Undoped GaSb epilayers have been grown on In0.3Ga0.7As/GaAs strain layer superlattice (SLS) by low pressure MOCVD. The SLS was used to reduce the large lattice mismatch (7%) between GaSb and GaAs. The epitaxial properties were examined by X-ray diffraction and Hall measurement. The X-ray diffraction peaks deteriorated when growth temperature exceeded 600°C. The hole concentration increased and the mobility decreased with increasing growth temperature. The better growth temperature is at the low end of the range between 550 and 635°C. This result is similar to that obtained from X-ray diffraction. The lowest 77 K concentration was 1.5×1016 cm-3 and the highest 77 K mobility was 1800 cm2/V·s. From the TEM photographs of GaSb/SLS/GaAs samples, it is observed that the dislocations have bent before reaching the epilayer surface, while the dislocations propagated up to the surface in GaSb/GaAs samples. From the comparisons of the electrical properties between GaSb epilayers grown on SLS/GaAs substrates and those grown directly on (100) GaAs substrates, it is found that the former have superior electrical properties.
A New Method of Field Measurements for Small-Aperture Magnets
Authors: Mitsuo Kikuchi Mitsuo Kikuchi , Hisayoshi Nakayama Hisayoshi Nakayama
Published: February 2005

The possibility of a new method for measuring the magnetic fields of very small-aperture magnets for linear colliders is discussed. The principle of this method is that a single wire with a not negligibly small radius is revolved with a constant frequency in a circle and the frequency spectrum of the induced voltage is analyzed. In actual cases, instead of revolving the wire, the magnet is revolved by a two-dimensional mechanism, which is driven by piezoelectric transducers and undergoes feed-back by a system with laser interferometers. The effect of the sensing-wire shape is also discussed.
Glow Auxiliary Electrical Discharge for CW High-Power CO2 Lasers
Authors: Suzuki Setsuo , Etsuo Noda Etsuo Noda , Osami Morimiya Osami Morimiya
Published: February 2005

A new discharge technique for DC glow auxiliary electrical discharge (GAED) lasers has been developed in order to realize efficient, stable and compact CW transverse-flow high-power CO2 lasers. The auxiliary discharge power source for GAED is common to that of the main discharge. This paper describes the discharge technique and characteristics of GAED. The luminous region of the positive column with auxiliary discharge became wider and more uniform than that without auxiliary discharge. The limited glow discharge power W

g

* (the discharge power for initiating unstable glow discharge) with auxiliary discharge was about 2.2 times that without auxiliary discharge. It was also found that the maximum value of W

g

* was obtained when the CO2 gas mixture ratio was 2-4%.
A Fokker-Planck Calculation of Bremsstrahlung Emission During Fast Wave Current Drive
Authors: Kawashima Toshinori Michishita
Published: February 2005

Bremsstrahlung emission during fast wave current drive is numerically calculated based on expansion of the electron distribution function in powers of inverse bounce frecluency. The distribution function is determined by solving a bounce-averaged Fokker-Planck equation. The resulting local bremsstrahlung emission shows poloidal-angle dependence. The angular spectrum of the emission along viewing lines is also given and is compared with the experimental results.
Influence of Secondary Electron Emission on the Characteristics of Langmuir Probes
Authors: Fuchs Hiroshi Amemiya
Published: February 2005

The characteristics of Langmuir probes have been calculated for such electron temperatures (≥15 eV) where the probe surface emits secondary electrons. Under these conditions, the floating potential of the probe shifts towards the plasma potential. The calculations provide a guideline by which to determine the plasma potential near the edge of fusion plasmas more accurately.
A Novel High-Resolution Scanning Electron Microscope for the Surface Analysis of High-Aspect-Ratio Three-Dimensional Structures
Authors: Nakagawa Hideo , Nomura Noboru , Koizumi Taichi , Anazawa Norimichi , Kenji Harafuji Kenji Harafuji
Published: February 2005

A scanning electron microscope (SEM) with an immersion-type objective lens has been developed. The objective lens generates a strong axial magnetic field of about 0.17 T at a wafer surface and has a very short focal length of about 2.5 mm. The SEM realizes an image resolution of 30 Å at 0.7 kV accelerating voltage. The capability to observe the bottom of a trench with a 5.3 µm depth and 0.55 µm width and that of a hole with a 0.46 µm diameter and 1.6 µm depth has been demonstrated at a low accelerating voltage of 0.5∼1.5 kV. A good measurement reproduceability of 5 nm/3σ (σ: standard deviation) has been achieved in the measurement of the 0.55 µm SiO2 line pattern on the bottom of a trench of 0.55 µm width and 5.3 µm depth. The SEM has been applied to the observation of 64MDRAM cell patterns with a
0.4 µm design rule.
Penetration of Hypervelocity Projectiles into Aluminum and Polyethylene Thin-Sheet Stacks
Authors: Nakamura Akiko , Yaguchi Ken-ichi , Fujiwara Akira , Toshihiko Kadono Toshihiko Kadono , Kohji Suguiyama Kohji Suguiyama
Published: February 2005

Nylon spheres of a nominal velocity of 3.6 km/s were penetrated into aluminum and polyethylene sheet stacks. Penetration depth, diameter of the holes produced on the sheets along the track, and mass of the recovered projectile fragments were determined to be a function of sheet thickness and spacing. As the sheet thickness decreased, but as long as the sheet spacing was sufficiently smaller than the projectile size, the results turned out to be similar to those for low-density continuous materials such as foamed polystyrene block.
Controlling the Crystal Orientations of Lead Titanate Thin Films
Authors: Ogawa Toshio , Atsuo Senda Atsuo Senda , Tohru Kasanami Tohru Kasanami
Published: February 2005

Various substrates were investigated for use in crystal-oriented PbTiO3 thin films deposited by rf magnetron sputtering. In fabricating ferroelectric thin films with controlled crystal orientations, a close relationship was found between the thermal expansion coefficients of the films and substrates. Where the thermal expansion coefficient of the substrate was larger than that of the film, as in the case of a single-crystal MgO substrate, horizontal compressive mechanical stress along the plane of the film led to a c-axis-oriented film. Conversely, where the thermal expansion coefficient of the substrate was smaller than that of the film, as in the case of a quartz glass substrate, tensile stress in the film gave rise to an a-axis-oriented film. The Curie point of the film material determined the amount of mechanical stress present during cooling. Based on the above, new substrates of glass ceramics for use in c-axis-oriented films were developed.
Preparation and Properties of Lead Zirconate-Titanate Thin Films
Authors: Iijima Kenji , Ichiro Ueda Ichiro Ueda , Koichi Kugimiya Koichi Kugimiya
Published: February 2005

Lead zirconate-titanate (PZT, PbZr
x
Ti1-x
O3, x=0.2-0.9) films with submicron thickness (600-900 nm) were prepared using an rf-magnetron sputtering technique. The crystal structure and the orientation of the films were studied as a function of the substrate temperature. The relationships between electric properties and the film compositions were elucidated. The films of x=0.90 exhibit a large remanent polarization of 46 µC/cm2 and small coercive force of 28 kV/cm. In addition, no fatigue after >1011 cycles under an accelerated bipolar stressing was observed.
PZT Thin Film Preparation on Pt-Ti Electrode by RF Sputtering
Authors: Abe Kazuhide , Tomita Hiroshi , Toyoda Hiroshi , Motomasa Imai Motomasa Imai , Yukari Yokote Yukari Yokote
Published: February 2005

Pt-Ti alloy films were studied for use as a lower electrode of the ferroelectric lead zirconate titanate (PZT) thin film capacitor. Pt-Ti alloy films with different Ti/Pt atomic ratios were first prepared by rf sputtering. Subsequently, PZT thin films were deposited also by rf magnetron sputtering on the Pt-Ti alloy metals. The Ti/Pt ratio in the alloy was found to strongly affect the crystal structure formation and the composition of the PZT thin films. The Ti/Pt ratio range from 0.02 to 0.17 was shown to bring about a preferable perovskite-type structure and a reproducible constant composition. The effect of Ti atoms in the Pt-Ti lower electrode was discussed in connection with the Pb atom evaporation rate.
Influence of Laser Fluence on Structural and Ferroelectric Properties of Lead-Zirconate-Titanate Thin Films Prepared by Laser Ablation
Authors: Kidoh Hideo , Ogawa Toshio , Yashima Hideyuki , Morimoto Akiharu , Shimizu Tatsuo
Published: February 2005

Ferroelectric lead-zirconate-titanate (PZT) thin films were deposited by excimer laser ablation on (100) MgO substrates with and without an electrode. The film composition was approximately the same as that of the target over a laser fluence range of 2.6 and 10 J/cm2·shot. Increase in the laser fluence enhances the film deposition rate and the crystallite size. In representative experiments, the remanent polarization and coercive field of the film prepared at a laser fluence of 9.2 J/cm2·shot were 28 µC/cm2 and 72 kV/cm, respectively.
Preparation of Lead Zirconate Titanate Thin Film by Hydrothermal Method
Authors: Shimomura Katsuhiko , Tsurumi Takaaki , Yoko Ohba Yoko Ohba , Masaki Daimon Masaki Daimon
Published: February 2005

A hydrothermal method for preparing thin films of crystalline PZT was developed by controlling the rates of nucleation and crystal growth. This method consisted of two steps of hydrothermal reaction. The first step (nucleation process) was that in which the TiO2 substrate reacted with the mixed solution of Pb and Zr to form PZT and/or PZ nuclei on the surface. Subsequently, the crystal growth of PZT was promoted as the next hydrothermal step (crystal growth process) by the reaction of the mixed solution of Pb, Zr and Ti. From the experimental results of PZT powder preparation, the conditions of the nucleation and crystal growth process were determined as at 150°C for 24 h and at 120°C for 48 h, respectively. It was verified that the thin films consisted of PZT polycrystals and showed ferroelectric properties.
Preparation of Ferroelectric (Pb, La)(Zr, Ti)O3 Thin Films by Sol-Gel Process and Dielectric Properties
Authors: Kawano Takafumi , Tadanori Sei Tadanori Sei , Toshio Tsuchiya Toshio Tsuchiya
Published: February 2005

Crack-free transparent ferroelectric polycrystalline PLZT (Pb, La)(Zr, Ti)O3 thin films with perovskite structure were prepared by dipcoating from a sol-gel process. Lead acetate, lanthanum-acetate, zirconyl nitrate and titanium tetrabutoxide were used as the raw materials. Acetic acid and triethylene glycol were used as solvents. Ferroelectric polycrystalline PLZT thin films with perovskite structure were obtained between 400°C and 850°C in air. The thin films deposited on platinum substrates and on silica glass substrates with sputtered ITO thin film were smooth and uniform. The dielectric constant of PLZT (7/65/35) thin film on the platinum substrate was about 788 at room temperature for 10 kHz and the loss tangent was about 0.03. The spontaneous polarization of PLZT (7/65/35) thin film was 8.0 µC·cm-2 and the coercive field was 20 kV/cm. The optical transmittance was above 60% in the range from 400 nm to 900 nm.
SrTiO3 Thin Film Preparation by Ion Beam Sputtering and Its Dielectric Properties
Authors: Yamamichi Shintaro , Sakuma Toshiyuki , Koichi Takemura Koichi Takemura , Yoichi Miyasaka Yoichi Miyasaka
Published: February 2005

SrTiO3 thin films have been prepared on Pd-coated sapphire substrates by ion beam sputtering of a SrTiO3 target, and their dielectric properties have been studied. Oxygen flow introduction was necessary to obtain good insulating films. Dielectric constant εr values were 190 and 240 for 430°C and 540°C substrate temperatures, respectively. These εr values were not dependent on film thickness in the range from 200 nm down to 50 nm. A 53 nm-thick film indicated leakage current density of less than 10-8 A/cm2 at up to 2 V, along with a 230 εr value.
Preparation of Tungsten-Bronze Thin Films
Authors: Adachi Masatoshi , Takeda Akira Kawabata
Published: February 2005

Tungsten-bronze films such as Pb0.6Ba0.4Nb2O6 (PBN), Pb2KNb5O15 (PKN), K3Li2Nb5O15 (KLN), K2.7Na0.3Li2Nb5O15 (KNLN) and K2BiNb5O15 (KBN) have been sputtered on sapphire and fused quartz substrates using ceramic targets. The sputtering conditions for growing tungsten-bronze structure films were investigated. (001)-oriented tungsten-bronze PBN films have been successfully grown by epitaxy onto (011̄2) sapphire substrates at a substrate temperature of around 650°C. The PKN films with tungsten-bronze structure have not been obtained by this sputtering using a target with the composition of stoichiometry. The c-axis-oriented films of KLN and KNLN have been grown on (011̄2) sapphire substrates. A KLN film sputtered on fused quartz at substrate temperatures higher than 480°C has also shown the [001]-axis orientation aligned perpendicular to the surface.
Reactive Planar Magnetron Sputtering System with Obliquely Facing Targets of Zn
Authors: Tominaga Kikuo , Masaki Shirai Masaki Shirai , Hiroshi Imai Hiroshi Imai
Published: February 2005

Planar magnetron sputtering system with obliquely facing targets was constructed to prepare ZnO films, and the possibility of the application of this sputtering system to the practical preparation of ZnO was studied. The films were prepared by the sputtering of Zn in O2 (100%) and the target-substrate configuration was arranged to avoid film bombardment by energetic oxygen particles. Gas pressure dependence of the c-axis orientation of the film was estimated. The presented sputtering system provided more highly c-axis-oriented polycrystalline films of ZnO than ordinary planar magnetron sputtering.
Search for a Material with Temperature-Independent Piezoelectric Constant d31 in Nb-Modified Pb(Zr, Ti)O3 Ceramics
Authors: Yokosuka Masaru , Ochiai Tutomu , Masakazu Marutake Masakazu Marutake
Published: February 2005

Investigations were made regarding the temperature characteristics of the piezoelectric constant d
31 of Pb(Zr, Ti)O3 ceramics. The composition, Pb1-x/2(Zr0.52Ti0.48)1-x
Nb
x
O3, was exclusively used, and the amount of Nb, x, was controlled in detail. The specimen near x=0.012 was found to have a temperature-independent value of d
31 over the temperature range between 20°C and 180°C.
Pb(Zn1/3Nb2/3)O3-Based Piezoelectric and Electrostrictive Ceramics
Authors: Kanegae Toshio , Koichiro Sakata Koichiro Sakata , Tadashi Takenaka Tadashi Takenaka
Published: February 2005

Perovskite-type Pb(Zn1/3Nb2/3)O3 (PZN)-based ceramics were prepared by a modification of 0∼10 mol% La(Ni1/2Ti1/2)O3 (LNT) or La(Co1/2Ti1/2)O3 (LCT). Effects on suppression of the pyrochlore phase in these ceramics were studied on the dielectric and electrostrictive properties. The ratios of the perovskite phase to the pyrochlore phase were more than 75% at 5∼10 mol% LNT or LCT modification. The temperature dependence of the dielectric constant, εs, shows a broad peak in the vicinity of room temperature. The transverse electrostrictive strain, S1=-2.5×10-5, of PZN ceramics with 5 mol% LNT modification was obtained under an applied electric field of 20 kV/cm.
(Bi1/2Na1/2)TiO3-BaTiO3 System for Lead-Free Piezoelectric Ceramics
Authors: Takenaka Tadashi , Kei-ichi Maruyama Kei-ichi Maruyama , Koichiro Sakata Koichiro Sakata
Published: February 2005

One of the (Bi1/2Na1/2)TiO3 (BNT)-based solid solutions, Ba-modified bismuth sodium titanate, (Bi1/2Na1/2)1-x
Ba
x
TiO3 (BNBT), is studied for its dielectric and piezoelectric properties as a new group of lead-free piezoelectric ceramics. A rhombohedral (Fα)-tetragonal (Fβ) morphotropic phase boundary (MPB) is shown to exist at x=0.06∼0.07 by X-ray data, and dielectric and piezoelectric properties. BNBT ceramics with the MPB composition are superior as piezoelectric ceramics in high-frequency ultrasonic applications or as piezoelectric actuator materials because of a lower free permittivity, ε33
T/ε0, and a high electromechanical coupling factor, k
t or k
33, along with high mechanical strength.
Processing of Porous 3-3 PZT Ceramics Using Capsule-Free O2-HIP
Authors: Hayashi Takashi , Sunao Sugihara Sunao Sugihara , Kiyoshi Okazaki Kiyoshi Okazaki
Published: February 2005

The processing of porous 3-3 type PZT ceramics was investigated using capsule-free O2-HIP. Porous PZT sintered bodies with relative density of about 50-80% were prepared from the green compacts with various amounts of spherical Polymethylmethacrylate (PMMA) particles. They exhibited a homogeneous microstructure with a bimodal distribution consisting of small pores of several µm and large pores of 50-80 µm in the PZT matrix. Little densification of porous PZT sintered bodies occurred after capsule-free O2-HIP treatment, and the neck growth of PZT interparticles was well developed, leading to the formation of porous 3-3 type PZT ceramics with a higher connectivity. The HIPed porous ceramics possessed a large permittivity and a small depolarizing factor of about half those of normally sintered porous PZT bodies.
Relations between Piezoelectric Properties and Microstructure in Poled Piezoelectric Ceramics by Applied Uniaxial Compressive Stress
Authors: Takashi Yamamoto Takashi Yamamoto
Published: February 2005

Relations among k
p, f
r·d, Q
m and domain configurations in some piezoelectric ceramics with various Q
m values were investigated under a polarization process (poling treatment) and depolarization process (applied stress treatment). In those materials, k
p values in Pb(Zr0.17)(Ti0.33)(Ni1/3Nb2/3)0.5O3 ceramics (low Q
m) decreased markedly with applied uniaxial compressive stress increase, and became 0.402 from 0.702 (initial k
p value) by 49 MPa, while 90° and 180° domain patterns revealed by chemical etching were not changed, even by either poling or applied stress treatments. However, k
p values in (Pb0.625Ca0.375)TiO3 ceramics (high Q
m) decreased slightly by 49 MPa, and a clear difference in the 90° domain pattern arrangement was observed before and after both poling and applied stress treatments.
Bimorph Type Actuators Using Lead Zinc Niobate-Based Ceramics
Authors: You Kondoh You Kondoh , Tomio Ono Tomio Ono
Published: February 2005

The authors examined the properties of actuators on several kinds of lead zinc niobate-based (PBZM) ceramics. Bimorph type actuators were manufactured from four kinds of PBZM family ceramics, and these ceramics were investigated regarding the properties relevant to actuators, i.e., hysteresis, creep, temperature coefficient, and so on. As a result, it has been found for the PBZM family ceramics that the relative dielectric constant influences the electrostrictive constant, but hardly influences hysteresis, creep, nor the temperature coefficient near room temperature. Therefore, an ideal actuator which has small hysteresis, small creep, and a large electrostrictive constant can be obtained. The actuator which had the best property as an actuator in this examination had about 2%-hysteresis and creep, with a minus 1%-temperature coefficient near room temperature.
Actuator Characteristics of Pb(ZrTi)O3 Composition near Morphotropic Phase Boundary
Authors: Kiyohara Masakatsu , Kato Ken-ichi , Kiyoshi Hayama Kiyoshi Hayama , Akashi Funamoto Akashi Funamoto
Published: February 2005

Piezoelectric actuator characteristics such as strain characteristics under DC voltage, temperature dependence, load characteristics and durability under repetitious DC voltage application were investigated in the (Pb0.845-Sr0.05-Ba0.105) ((Zr
x
Ti1-x
)0.95-Sn0.045-Nb0.005)O3 series (0.49≤x≤0.55). The piesoelectric characteristics changes markedly owing to the difference in crystal structure. The compositions in the tetragonal phase are superior for actuator applications.
Porous Piezoelectric Ceramic Transducer
Authors: Mizumura Koichi , Kurihara Yoshiaki , Ohashi Hiroshi , Susumu Kumamoto Susumu Kumamoto , Kiyonori Okuno Kiyonori Okuno
Published: February 2005

Porous piezoelectric ceramics of Pb(Zr, Ti)O3, (P-PZT), have been newly developed to apply to transducers in an echo sounder. The P-PZT was prepared from a mixture of PZT and poly-methyl-methacrylate (PMMA) powders. The piezoelectric characteristics of the P-PZT such as the dielectric constant (ε), voltage output constant (g constant), acoustic impedance (Z
c) and Q were evaluated. The P-PZT was employed in an echo sounder of 200 kHz, and its transmitting and receiving properties were measured in water. In these measurements, the P-PZT showed suitable characteristics for the echo sounder, which required high sensitivity, wide frequency bandwidth and high resolution. High sensitivity was realized by the large g constant and low Z
c of P-PZT which made the impedance matching with water much easier. In the acoustic response to the burst wave, the rise and fall time were shortened to 1/3 that of the conventional PZT transducer.
Characteristics and a New Control Method of a Same-Phase Drive-Type Ultrasonic Motor
Authors: Takano Takehiro , Tomikawa Yoshiro , Ogasawara Toshiharu , Kusakabe Chiharu
Published: February 2005

This paper deals with a same-phase drive-type ultrasonic motor, using two degenerate bending vibration modes of a disk. Characteristics of the motor driven at low input power are shown. Signal waves picked up from a rotor are also shown. It is found that these signals are closely related to revolution states of the motor. Moreover, a new control method for the motor is proposed and tried.
Fabrication of Multilayer Positive Temperature Coefficient Resistor by Electrode Bonding Method
Authors: Arakawa Junichi , Shinjiro Tashiro Shinjiro Tashiro , Hideji Igarashi Hideji Igarashi
Published: February 2005

Chip-type positive temperature coefficient (PTC) resistors with multilayer structure were fabricated by an electrode bonding method in order to ascertain the availability of multilayer structure in PTC elements. Voltage dependence of their resistivity was measured apart from heat generation caused by current flowing through the elements. Large voltage dependence was observed for multilayer PTC ceramics (MLPTC's) because potential barrier height depended on electric field strength applied to each grain boundary. Current-time characteristics were examined as a parameter for applying field. The current flowing through MLPTC's was saturated at shorter intervals than that for disk-type PTC ceramics.
Dielectric Characteristics of (A1/2
1+·A1/2
3+)TiO3 Ceramics at Microwave Frequencies
Authors: Takahashi Hisakazu , Baba Yoko , Ezaki Kenichi , Okamoto Yasuhiko , Shibata Kenichi , Kazuhiko Kuroki Kazuhiko Kuroki , Shoichi Nakano Shoichi Nakano
Published: February 2005

We have investigated the dielectric characteristics at microwave frequencies of perovskites with the formula (A1/2
1+·A1/2
3+)TiO3, (where A1+ represents an alkali metal from the lithium to potassium series and A3+ represents a member of the lanthanide series from lanthanum to lutetium). It was found for the first time that in the case of Li1+ substitution at the A1+ site, the larger the ionic radius of the element which substituted at the A3+ site, the higher the dielectric constant was and the greater the negative shift of the temperature coefficient of resonant frequency was. For the (1-x)(Li1/2
1+·Sm1/2
3+)TiO3-x(Na1/2
1+·Sm1/2
3+)TiO3 system at 3 GHz, high dielectric properties of εr=81, Q=2050 and τf=+17ppm/ °C were obtained when x=0.4.
Optical Associative Memory Using LiNbO3:Fe Hologram
Authors: Tanaka Yukio , Chen Zhiming , Tadashi Kasamatsu Tadashi Kasamatsu , Tadashi Shiosaki Tadashi Shiosaki
Published: February 2005

Experimental investigation is presented on an all-optical associative holographic memory with storage of more than one image using an iron-doped lithium niobate single crystal in which memories can be written, erased and rewritten without developing treatment. Several images are multiply stored in the single crystal volume hologram by sequentially changing their own corresponding reference beams. Then using an image input, an output image is read out. This output image most closely resembles the input image. Threshold processing due to the sublinear photorefractive effect in the crystal is used to single out a distinct diffracted beam from the hologram.
Generation of Optical Phase-Conjugate Wave in Undoped Photorefractive Ba2NaNb5O15
Authors: Isoda Kunihiko , Iba Jun , Uesu Yoshiaki , Kiat J. M. , Aubree J.
Published: February 2005

An optical phase-conjugate wave (OPCW) was generated in undoped photorefractive Ba2NaNb5O15 by a degenerate four-wave mixing technique in varying wavelengths and temperatures. The maximum reflectivity (∼0.1%) was obtained at the wavelength of 488 nm among the characteristic wavelengths of Ar ion laser. Above 60°C, it was found that two types of gratings were formed in the crystal by the different processes, i.e., the diffusion of the electron and the drift of the ion. These processes explain the temperature dependence and the relaxational behavior of the OPCW power.
An Equivalent Circuit Expression of an Ultrasonic Motor and Measurement of Its Elements –In the Case of L1-B8 Multimode Rectangular Thin-Form Motor–
Authors: Tomikawa Yoshiro , Yaginuma Masatoshi , Takano Seiji Hirose
Published: February 2005

An equivalent circuit expression of an ultrasonic motor is investigated from the viewpoint of systematization of research on an ultrasonic motor. That is, the authors considered the equivalent circuit and measured its elements in actual motion of the motor, which consisted of a L1-B8 multimode rectangular vibrator of a thin form. This investigation is useful for analysis of the actual motor characteristics and the motor design. The measuring method of the elements and the results are described herein.
C-V Characteristics of MOS Structures Fabricated of Al-Doped p-Type 3C-SiC Epilayers Grown on Si by Chemical Vapor Deposition
Authors: Shinohara Mikiya , Yamanaka Mitsugu , Misawa Shunji , Hajime Okumura Hajime Okumura , Sadafumi Yoshida Sadafumi Yoshida
Published: February 2005

MOS structures were fabricated from Al-doped p-type 3C-SiC epilayers grown on Si by chemical vapor deposition. Their C-V characteristics were studied for the first time at 400 Hz, 10 kHz and 100 kHz. Accumulation, depletion, deep depletion and inversion regions were observed in the C-V curves. The increase of capacitance in the inversion region was observed for reverse sweep of gate bias at 400 Hz and 10 kHz. The fixed oxide charge density and the space charge density in 3C-SiC were estimated to be on the order of 1012 cm-2 and 2.8×1018 cm-3, respectively.
Optical Activity of Incommensurate Phases of (C3H7NH3)2MnCl4
Authors: Kazuya Saito Kazuya Saito , Jinzo Kobayashi Jinzo Kobayashi
Published: February 2005

By applying the HAUP (high-accuracy universal polarimeter) method, (C3H7NH3)2MnCl4 was found to be optically active in its incommensurate phases, e.g., g
33=1.1×10-5 in the γ phase at 83.0°C and g
33=2.4×10-5 in the ε phase at -139.0°C. The temperature dependence of g
33 was obtained. Commensurate domains were found to begin to grow below -139°C in the ε phase.
Preparation of Thin Silicon-on-Insulator Films by Low-Energy Oxygen Ion Implantation
Authors: Yukari Ishikawa Yukari Ishikawa , Noriyoshi Shibata Noriyoshi Shibata
Published: February 2005

Silicon-on-insulator (SOI) structures have been formed by oxygen implantation with the ion energy of 15-30 keV in silicon wafers. The ion implantation conditions which produce the SOI structure have been investigated both by calculation and experiments. As-implanted layers were analyzed by Auger electron spectroscopy and cross-sectional transmission electron microscopy. The thicknesses of the SOI layer and the buried amorphous SiO
x
layer are 48 and 61 nm, respectively, under the conditions at the O+ ion energy of 25 keV, with the dose of 2×1017 ion/cm2, and at about 450°C. The SOI layers are homogeneous and have sharp Si/SiO
x
interfaces.
Characterization of Hydrogenated Amorphous Silicon Films by a Pulsed Positron Beam
Authors: Suzuki Ryoichi , Kobayashi Yoshinori , Mikado Tomohisa , Matsuda Akihisa , Mcelheny Peter J. , Mashima Satoshi , Ohgaki Hideaki , Chiwaki Mitsukuni , Tetsuo Yamazaki Tetsuo Yamazaki , Takio Tomimasu Takio Tomimasu
Published: February 2005

A low-energy pulsed positron beam was, for the first time, applied to the characterization of hydrogenated amorphous silicon films (∼1 µm in thickness) deposited by means of plasma-enhanced chemical-vapor deposition. By the use of a pulsed positron beam, positron lifetime spectra were measured on four films deposited under different rf-power densities. In two of the films prepared at the intermediate power densities, a long-lived component (τ≃9 ns) was observed, which indicates that a high concentration of voids exists. A component with a lifetime of 319 ps, which is due to trapped positrons at divacancies or small vacancy clusters, was observed in the film prepared at the lowest power density, while a component with a lifetime of 390 ps-440 ps, which is due to trapped positrons at large vacancy-type defects, was observed in the other films. The results clearly indicate that the defect properties are strongly influenced by the rf-power density.