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We have developed a novel wafer-scale uniform layer-by-layer etching technology based on the etching reaction of oxygen molecules with Ge surfaces. The advantages of this etching technology are as follows. (1) Layer-by-layer etching can be achieved, yielding an atomically flat step-terrace surface. (2) Because of the very small activation energy (

This paper demonstrates a 0.8-V rail-to-rail operational amplifier (op-amp) for ultra-low-power Internet-of-Things (IoT) sensor nodes. To suppress the leakage current in the logic part, a FinFET technology with 0.4-V threshold voltage (V t ), is chosen. To realize the rail-to-rail operation in the small common-mode (CM) voltage headroom, V DD –V t , a 4-stage chopper-stabilized topology with high-pass filters, multi-path hybrid-nested Miller compensation, and a push-pull output stage are introduced. A near-V t amplifier is also introduced to the second stage to boost the gain. The fabricated op-amp shows 1MHz Gain-Bandwidth in whole of the CM voltage range.

This paper reports the positive bias temperature instability (PBTI) characteristics for n-type fin-channel tunnel field-effect transistors (TFETs) with high-k gate stacks. The subthreshold slope (SS) is not degraded at all while the threshold voltage (V th ) shifts in the positive direction by the PBTI stress. The activation energy of ΔV th for TFETs is almost the same as FinFETs, indicating that the PBTI mechanism for TFETs is almost the same as FinFETs. It was found that by applying a positive bias to the n+-drain, the PBTI lifetime is dramatically improved as compared with that in the conventional stress test. This is because carrier injection from the n+-drain is the main cause of the PBTI, especially for n-type TFETs. Thus, to accurately predict the PBTI lifetime of n-type TFETs, it is necessary to apply a drain bias for the reliability test.

We investigated the effects of the addition of chitosan fiber (biomass nanofiber made by Sugino (BiNFi-s)) to polyether-based thermoplastic polyurethane (TPU) on material properties. BiNFi-s (2 and 5 wt %)/TPU composite materials were prepared via compression molding, and glass fiber (2 and 5 wt %)/TPU composite materials and plain TPU were also prepared for comparison. The glass transition temperature was analyzed using differential scanning calorimetry, and the crystal structure was investigated using X-ray diffraction. 20-mm-long test specimens with cross-sectional dimensions of 1 mm × 1 mm were cut from sheets of the composite materials, and three-point bending tests were carried out using a universal testing machine to investigate their mechanical properties and shape memory. The addition of BiNFi-s or glass fiber to TPU did not influence the glass transition temperature, although the crystal structure changed from semi-crystalline to amorphous. The elastic modulus increased 40% by the addition of 5 wt % BiNFi-s (2.31 MPa) compared with plain TPU (1.65 MPa), and these composites exhibited shape recovery with clinically relevant changes in temperature. The addition of 5 wt % BiNFi-s into TPU resulted in an improvement in the elastic modulus without any decrease in the shape memory effect. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1151-1156, 2017.

We investigated the effects of CO2 laser irradiation combined with acidulated phosphate fluoride (APF) application on the demineralization of enamel. APF gel was applied to the buccal enamel of human premolars and CO2 laser was applied. After the specimens were immersed in demineralization solution for 72 h, they were subjected to depth-dependent micro-CT and nanoindentation analyses. Micro-X-ray diffraction and X-ray photoelectron spectroscopy were performed to analyze the surfaces. Some surface regions of the enamel in specimens that were laser-irradiated with low output and APF-treated showed significantly higher values of MD and hardness than specimens treated with APF alone. A higher fluoride concentration in the enamel surface was observed in specimens treated with CO2 laser irradiation plus APF gel application. In conclusion, CO2 laser irradiation with low output is preferable to improve acid resistance.

Polycrystalline-silicon (poly-Si) and crystalline-silicon (crystal-Si) channel FinFET CMOS inverters were successfully fabricated and the variations of threshold voltage (V t ) for their individual n- and p-channel transistors and the logic gate V t (V Thc ) for the inverters were systematically investigated. It was found that poly-Si n- and p-channel devices show about 3 and 5 times larger σV t values, respectively and about 2 times larger σV Thc as compared to those in crystal-Si channel ones. The calculated σV THC values by using the error propagation low are good agreement with experimental results.

The purpose of this study was to improve the adhesion and extension of human gingival epithelial cells (HGECs) to the yttria-stabilized zirconia polycrystal (Y-TZP) surfaces by immobilization of insulin-like growth factor 1 (IGF-1). Surface analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that IGF-1 was successfully immobilized on the Y-TZP surfaces. There was no significant difference between the number of cells attached to the IGF-1-immobilized Y-TZP surfaces and on the as-polished Y-TZP surfaces either at 3 or 72 h. However, IGF-1-immobilized Y-TZP surfaces yielded a significantly higher expression of integrin β4 mRNA and laminin-5 mRNA, and enhanced adhesion strength of HGECs after 72 h of incubation. There was no difference between the amount of adhered Streptococcus gordonii (S. gordonii) found on the IGF-1-immobilized Y-TZP surfaces and on the as-polished Y-TZP surfaces. These results suggested that the IGF-1-immobilized Y-TZP surfaces developed using the method reported herein enhanced the adhesion and extension of HGECs to the Y-TZP surfaces without enhancing S. gordonii adhesion.

Introduction The aim of this study was to establish a novel method for simulating orthognathic surgery in 3-dimensional (3D) space. Methods This system mainly consists of 6 procedures: (1) reconstruction of a virtual skull model (VS) from presurgical computed tomography scans; (2) reconstruction of virtual dentition models from 3D surface scanning of dental casts occluded at presurgical and postsurgical intercuspal positions (VD1 and VD2, respectively); (3) reconstruction of a preliminary fusion model of VS and VD1 by an initial intermodality registration; (4) reconstruction of another preliminary fusion model of VS, VD1, and VD2 by a second intramodality registration; (5) repositioning of bony segments by a third intramodality registration and reconstruction of final fusion models at presurgery and postsurgery; and (6) 3D analysis of the movement of bony segments. To test this system, 2 patients with severe skeletal deformities, who had undergone presurgical orthodontic treatment, were used as models. Registration accuracy was determined by the root mean squared distance between the corresponding fiducial markers in a set of 2 images. Results and Conclusions The sum of the root mean squared error of the 3 registration processes was less than 0.4 mm in both patients. This simulation system could be used to precisely realize the presurgical and postsurgical occlusal relationships and craniofacial morphology of a patient with severe skeletal deformities, and to quantitatively describe the movement of a given anatomical point of bony segments. It is assumed that there could be significant benefits in sharing visual and quantitative 3D information from this simulation system among orthodontists and surgeons.

The titanium nitride (TiN) gate electrode with a tunable work function has successfully been deposited on the sidewalls of upstanding Si-fin channels of FinFETs by using a conventional reactive sputtering. It was found that the work function of the TiN (phiTiN) slightly decreases with increasing nitrogen (N2) gas flow ratio, RN=N2/(Ar+N2) in the sputtering, from 17% to 100%. The experimental threshold voltage (Vth) dependence on the RN shows that the more RN offers the lower Vth for the TiN gate n-channel FinFETs. The composition analysis of the TiN films with different RN showed that the more amount of nitrogen is introduced into the TiN films with increasing RN, which suggests that the lowering of phi TiN with increasing RN should be related to the increase in nitrogen concentration in the TiN film. The desirable Vth shift from -0.22 to 0.22 V was experimentally confirmed by fabricating n+ poly-Si and TiN gate n-channel multi-FinFETs without a channel doping. The developed simple technique for the conformal TiN deposition on the sidewalls of Si-fin channels is very attractive to the TiN gate FinFET fabrication

We investigated the optimum gate workfunction (phim) for four-terminal-driven double-gate MOSFETs (4T-XMOSFETs) using device simulation. Threshold voltage (Vth) controllability for the 4T-XMOSFETs was investigated in relation to the initial Vth in the double-gate mode (VthDG) based on comprehensible modeling of the devices. It was shown that I--V characteristics for the 4T-XMOSFETs are categorized into two states while VthDG forms a boundary. If Vg2 is less than VthDG, i.e., VthSG is larger than VthDG, subthreshold-slope (S) keeps low value. If Vg2 is larger than VthDG, i.e., VthSG is less than VthDG, S significantly deteriorates. As a result, setting VthDG, i.e., phim at a low value and thus using VthSG larger than VthDG, is preferable for improving the 4T-XMOSFET performance. To confirm it, both static and dynamic characteristics for CMOS with low (band-edge) phim (phimn=4.17 eV for NMOS, phimp=5.25 eV for PMOS) were compared with that with high (mid-gap) phim(phimn=phimp =4.71 eV) DGs. It was found that CMOS 4T-XMOSFET with low (band-edge) phim DGs showed a higher Ion and a shorter inverter delay than that with high (midgap) phim DGs

A high aspect ratio and damage-free vertical ultrathin channel for a vertical-type double-gate MOSFET was fabricated by using low-energy neutral-beam etching (NBE). NBE can completely eliminate the charge build-up and photon-radiation damages caused by the plasma. The fabricated FinFETs realize a higher device performance (i.e., higher electron mobility) than that obtained by using a conventional reactive-ion etching. The improved mobility is well explained by the NB-etched atomically flat surface. These results strongly support the effectiveness of the NB technology for nanoscale CMOS fabrication

We report successful growth of high-quality thin films with clean and completely precipitate-free surface, suitable for device applications, by applying a new concept and method to the substrates. The concept consists in generation of artificial steps of controlled height and width, and desired shape on the surface of the substrate. The width of the step is chosen so that it is equal to the double of the migration (surface diffusion) length of the atomic species in the growth process of the film. If precipitates occur, they will be selectively gathered to the step edge where the free energy is lowest. Using this new method, we have successfully obtained by MOCVD high-quality precipitate-free Bi-2223 and Bi-2223/Bi-2212-superlattice thin films on (100) SrTiO3 substrates with artificial steps of controlled width and height. These as-grown films have been further used to fabricate patterned intrinsic Josephson junctions. Completely precipitate-free films offer a strong advantage for integration, and generate new possibilities for the device fabrication.

Ultrathin-channel formation of a vertical-type double-gate metal oxide semiconductor field effect transistor using a low-energy neutral-beam etching (NBE) is proposed. The NBE can completely eliminate charge buildup and photon radiation damage from the plasma. By optimizing NBE conditions, rectangular vertical channels were fabricated with a SiO2 hard mask under low-energy NBE conditions.

High quality superconducting thin films of HTS have been grown by MOCVD on substrates with artificial steps of predefined height and width. The surface of the films grown on the steps having width equal to the 'double of the migration length' of the atomic species depositing on the substrate is totally free of precipitates: precipitates are gathered at the step edges where the free energy is lowest. The method has several advantages: it is simple, universal (it is independent of the materials, substrates, deposition technique or application) and allows control of precipitates segregates so that the quality and growth conditions of the films are the same as for the films grown on conventional substrates. The method is expected to result in new opportunities for the device fabrication, design and performance.

The property of an accumulation-mode double-gate (DG) metal–oxide–semiconductor field-effect transistor (MOSFET) has thoroughly been investigated on the basis of experimental data and simulation results. Both accumulation- and inversion-mode DG-MOSFETs have been fabricated by novel vertical DG-MOSFET fabrication process technology. It is experimentally demonstrated that accumulation-mode DG-MOSFETs show a severe influence of channel thickness (TSi) on threshold voltage (Vth) and subthreshold slope (S) as compared with inversion-mode ones. By decreasing TSi, however, S is dramatically improved to the same value as that for the inversion-mode one. The short-channel effects (SCEs) for the accumulation-mode DG-MOSFETs have been explored using device simulation. The simulation result shows that, by decreasing TSi to 10 nm, the trend of the SCEs for the accumulation-mode DG-MOSFETs becomes the same as that for the inversion-mode one down to an effective gate length of 10 nm. It is also demonstrated that, by using n+-DGs, an appropriate Vth as well as a low S can be attained for an accumulation-mode PMOS vertical DG-MOSFET.

We have investigated the fabrication processes and device characteristics for n-channel triple-gate metal–oxide–semiconductor field-effect transistors (MOSFETs) on (100) silicon-on-insulator substrates. By optimizing the diagonal ion implantation conditions for the narrow fin channel, the fabricated triple-gate device showed an electron mobility almost compatible to a planar MOSFET with a supreme subthreshold slope of 64 mV/decade and drain induced barrier lowering (DIBL) of 15 mV/V.

We present an experimental study of effective carrier mobility ( µeff) of multi-fin-type double-gate metal–oxide–semiconductor field-effect transistors (FinFETs) with a (111) channel surface fabricated by orientation-dependent wet etching. The peak values of the obtained µeff of electrons and holes are approximately 300 and 160 cm2/(V s), respectively, which are close to those in (111) bulk metal–oxide–semiconductor field-effect transistors (MOSFETs). Moreover, the effective electric field (Eeff) dependence of the µeff of electrons and holes shows a good agreement with the mobility universal curves of (111) bulk MOSFETs. These results indicate that the quality and channel surface roughness of Si-fins by orientation-dependent wet etching are excellent. The obtained results of µeff are very useful for the modeling and design of FinFET-complementary metal–oxide–semiconductor (CMOS) circuits and the developed wet etching technique is very attractive in the fabrication of ultrathin and high-quality Si-fin channels.

This paper describes a comprehensive study on the threshold voltage (V/sub th/) controllability of four-terminal-driven double-gate (DG) MOSFETs (4T-XMOSFETs) with independently switched DGs. Two types of 4T-XMOSFETs (fin and vertical) are experimentally demonstrated and their V/sub th/ controllability is thoroughly investigated in relation to the initial V/sub th/ in the DG-mode based on comprehensible modeling of the devices. Based on the investigation and simulated predictions, device design guidelines for 4T-XMOSFETs are proposed. Decreasing the workfunction of the DGs and increasing the oxide thickness of the second gate (T/sub ox2/) are preferable for improving the performance of the 4T-XMOSFET. The optimum workfunction of DGs for attaining low I/sub off(stand-by)/ and high I/sub on(active)/ under the limited V/sub g2/ condition is also proposed.

Work function (@f"m) of metal transistor gates was controlled by using Al-Ni and Ni-Ta alloys made through an interdiffusion process, in which stacks of different metals were annealed. In addition to conventional capacitance-voltage measurements for @f"m evaluation, @f"m uniformity was also measured microscopically. The average @f"m of the Al-Ni alloy was successfully changed compared to that of pure Al by interdiffusion at 500 ^oC. The @f"m nonuniformity of Al-Ni, however, was problematic. Though Ni-Ta alloys required interdiffusion at a higher temperature of 700 ^oC, the Ni-Ta alloys had better @f"m uniformity. Thus, the Ni-Ta alloy is a more suitable candidate for use in metal gates of high-integrity transistors.

This paper presents, for the first time, the experimental electron mobility in FinFETs with a (111) channel surface fabricated by the orientation-dependent wet etching. The maximum electron mobility (ueff) is around 300-cm2 /V-s, which is close to that in the (111) bulk MOSFETs. Moreover, the value of ueff is comparable or better than the reported ones in the usual FinFETs with a (110) channel surface prepared with careful surface treatments. This result indicates that the quality and channel surface roughness of the Si-fins by the orientation-dependent wet etching are much better than those fabricated by the conventional reactive ion etching (RIE) process.

The corrosion and tarnish behaviors of three Ag-based alloys (Ag-Pd-Cu-Au alloy, Ag-In alloy, and Ag-Sn-Zn alloy) in polyvinylpyrrolidone iodine (povidone-iodine) solution were examined. The degree of tarnish was evaluated by visible-ray spectrocolorimetry. Corrosion potential measurements and analyses of corrosion products by X-ray diffractometry were carried out to elucidate the corrosion mechanism. The corrosion rate of the three Ag-based alloys in povidone-iodine solution at its practical concentration used as a gargle solution was so fast that the alloys tarnished within 10 seconds of immersion with the formation of AgI. Thermodynamic consideration and the results of surface analysis by X-ray diffractometry revealed that the main anodic and cathodic reactions were Ag + I(-)--AgI + e- and I2 + 2e(-)--2I- respectively.

YBCO films deposited from a stoichiometric (Y123) target via a large-area PLD system have consistently been found to be Y-rich in composition as well as characterized by pores. Use of an off-stoichiometric target with increased Ba and Cu content proved to be an effective method to compensate for the deficiency in barium and copper in the films. Films with composition closer to the ideal stoichiometric ratio have been obtained from the off-stoichiometric target, including significantly reduced pore density, improved microstructure and higher critical current density ( J c ) in excess of 2 MA/cm 2 at 77.3 K over a 2 ″ -diameter area. Furthermore, it was found out that the dense and smooth YBCO film deposited from the off-stoichiometric target needed ex situ oxygen annealing to reach fully-oxygenated state.

胃癌術後例の血中ビタミンB1値について検討した.対象は胃癌術後3カ月以上経過した112例で,ビタミンB1値を測定し大腸癌術後症例25例のB1値と比較した.また胃癌術後例で低値を示した症例にビタミンB製剤の内服投与を行いB1値の変動を検討した.さらに胃癌術後例にアンケートを行いビタミンB1低値例の背景因子を検討した.結果,胃切除後例の血中ビタミンB1値は平均2.9μg/dl,大腸癌術後例は3.0μg/dlで両群に有意差はなかった.またビタミンB1欠乏は胃癌術後例の12例(10.7%),大腸癌術後例の1例(4%)にみられ,両群に有意差はなかった.またビタミンB製剤の内服で全例B1値が上昇した.アンケートの結果では低値例では正常例と比し体重減少率が高かった.以上からB1値の低下は胃切除術に起因したものではないが,低値を示す例があり,適切な食事指導や投薬などの細かな配慮が重要であると考えられた.

The purpose of this study is to clinically confirm the adhesive effect of a vinyl-thiol primer (V-Primer) for precious alloys. Further, we examined the failure of resin-bonded bridges (RBBs) in order to improve the clinical longevity of RBBs, and to analyse the causes of failure. Twenty-six RBBs were bonded with V-primer and Super Bond C & B between May 1987 and December 1997 in the Dental Clinic of the Health Sciences University of Hokkaido. The RBBs were made of silver-palladium-gold alloy or metal-ceramic gold alloys. V-primer was effective in bonding Super Bond C & B to the RBBs made of silver-palladium-gold alloys. Ten prostheses had functioned satisfactorily for 8-11 years. However, six of the 26 RBBs had become detached. In four of the six failed RBBs, the type of bond failure was a mixture fracture in the resin-enamel interface. Our results suggest that: (1) V-primer is effective on RBBs made of silver-palladium-gold alloys. (2) Mechanical retention is necessary for retainers to improve the longevity of RBBs when the V-primer is applied to RBBs made of precious alloys without copper. (3) The RBB should not be applied to abutment teeth that have differences in tooth mobility.

The corrosion and tarnish behavior of a dental casting Pd–25Ag–18Cu–12Au alloy in 0.1% Na2S solution at 37 °C was investigated using potentiodynamic polarization and spectrocolorimetric techniques. The surface film was characterized by X-ray photoelectron spectroscopy (XPS). This alloy exhibited markedly higher resistance to corrosion and tarnish than did the Ag–20Pd–18Cu–12Au alloy in current clinical use. XPS spectra indicated the presence of a thin sulphide film composed of PdS. It was found that the PdS film is very protective and is responsible for the passivity of the Pd–25Ag–18Cu–12Au alloy in 0.1% Na2S solution.

In high temperature superconductors (HTS) the coherence length along non-c-axis directions is longer. This feature can be useful when designing electronics devices based on HTS. Therefore, growth and characterization of non-c-axis oriented thin HTS films is of great interest. In this paper we present our comparative results on preparation by MOCVD and characterization by atomic force microscopy, X-ray diffraction and transport measurements of as-grown (1 1 9) Bi-2223 and (1 0 3) Y-123 thin films on (1 1 0) SrTiO3. The films have shown the same type of surface morphology (grains with mountain-range shape, aligned in parallel chains to the [0 0 1] substrate’s azimuth). This morphology is the result of the orientation relationship between the (1 1 9) Bi-2223 or (1 0 3) Y-123 and (1 1 0) SrTiO3. The transport measurements with temperature revealed strong anisotropy of the films in the normal state region when the measuring current has been applied in-plane, parallel and perpendicular to the edges (from the basal plane) of the mountain-range grains. Higher values for Tc0 have been obtained for the Y-123 films (42 K) than for the Bi-2223 ones (31 K). The both films are as-grown and non-oxygenated ones.

Superconducting (0 0 l) thin films of SmBa2Cu3Oy have been grown by MOCVD on (0 0 1) SrTiO3 and (0 0 1) LaAlO3 substrates. The films on both substrates are smooth with RMS of 1.428 and 1.037 nm respectively, but have different morphology (revealed by atomic force microscopy) for the same synthesis conditions. The films grown on SrTiO3 have shown rectangular- or square-type terraces. The height between the neighboring terraces was corresponding to the c-axis length of one unit cell. This type of morphology is due to the two-dimensional nucleation and growth mechanism. In the case of the films on the LaAlO3 the surface morphology consisted of irregular grains (close to spherical). For both situations we have not found any evidence for a spiral growth mechanism. Therefore, our films are suitable for electronics applications of integrate type and not only. The as-grown films were oxygen deficient and due to this exhibited rather poor superconducting properties. Oxygen annealing at temperatures of 500–600 °C increased Tc(R=0) up to 87.8 K.

Thin films of (Ca 1− x Ba x )CuO 2 ( x =0–1) have been grown on (0 0 1) SrTiO 3 by metal organic chemical vapor deposition. These films are potential candidates as barrier layer for SIS and/or SNS Josephson junctions. For this purpose, the films should be flat and smooth. In this regard we have investigated the possibility of decreasing the films roughness by the control of the Ba/Ca ratio, the substrate temperature and oxygen partial pressure during the growth of the film. The minimum mean square root roughness and regular morphology are obtained for the x =0.3–0.5. In the samples with x =0.5 the highest intensity of the X-ray diffraction peaks for the (Ca 0.5 Ba 0.5 )CuO 2 phase and the lowest for the impurity phases were attained at a substrate temperature of 750–780 °C and oxygen partial pressure of 15 Torr.

The anodic corrosion behavior of an experimental Ag-15Pd-18Cu-12Au alloy in 0.1% Na(2)S solution in relation to its microstructure was investigated using potentiodynamic and potentiostatic polarization techniques with analyses of corrosion products by X-ray diffractometry, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The role of Pd in improvement of the corrosion resistance was also investigated. In the potential/current density curve, three distinct current peaks, at -520 mV (peak I), -425 mV (peak II) and -175 mV (peak III), were observed. The Ag-rich alpha(2) matrix with coarse Cu and Pd-rich lamellae was the most corrosion-susceptible region, and this region was preferentially corroded at peak I with the formation of granular deposits of Ag(2)S. A small amount of Ag-Cu mixed sulfide deposited on the Cu and Pd-rich coarse particles and dissolution of Ag as AgO(-) might have occurred in parallel with Ag(2)S formation at peak II. Enrichment of Pd on the alloy surface occurred at peak III due to preferential dissolution of Ag and Cu. A high level of corrosion resistance was attained with the formation of a thin Pd-rich sulfide film, which enhanced the passivity of the alloy in an alkaline sulfide solution. It was found that passivity is an important phenomenon not only for base metal alloys but also for noble metal alloys to maintain high levels of resistance to corrosion and tarnishing in sulfide environments.

The functional split-gate type trigate flash memory cell transistors have successfully been fabricated for the first time, and their threshold voltage (Vt) variations before and after NOR-mode program/erase cycle have systematically been compared with the stack-gate ones. It was experimentally found that split-gate type cell transistors with the same control gate length (LCG) of 176 nm show much smaller Vt distribution after erase compared to those of stack-gate ones. Moreover, the measured source-drain breakdown voltage (BVDS) is higher than 3.1 V even the LCG was down to 76 nm. This indicates that the developed split-gate type trigate flash memory is very effective for scaled NOR-type flash memory with highly suppressed over-erase.

Orientation control of high T c superconductors is essential for superior device performance, because the coherence length is longer along the non- c -axis directions than along c -axis direction. In this study, we report on successful preparation of (1 1 9) oriented Bi 2 Sr 2 Ca 2 Cu 3 O 10 (Bi-2223) films by metalorganic chemical vapor deposition using (1 1 0) SrTiO 3 substrates. Atomic force microscopy observations of the (1 1 9) Bi-2223 films are reported for the first time. Our films have an in-plane aligned mountain-range-shaped surface morphology. This morphology is resulting from the epitaxial relationship between the (1 1 9) Bi-2223 film and (1 1 0) substrate. The obtained films exhibited a large in-plane anisotropy as revealed by resistivity measurements and surface morphology observations.

The preparation of non c-axis oriented high Tc superconductor films with longer coherence length is one of the key technologies toward realization of viable Josephson devices. For the first time, we have succeeded in growing in-plane aligned (1 1 9)Bi-2223 films on (1 1 0)SrTiO3 substrates by metalorganic chemical vapor deposition using a two-step growth temperature procedure. This procedure was found to be effective for orientation control and phase control in comparison with a fixed growth temperature procedure. As a result, superconducting properties were improved. The surface morphology observed by atomic force microscopy showed an in-plane aligned mountain-range shape, which strongly reflects the orientation relationship between the (1 1 9)Bi-2212 film and (1 1 0)SrTiO3 substrate.

We have fabricated YBCO superconducting thin films on MgO(100) substrates by MOMBE. As source materials, we have used fluorine-free s-diketonate chelates of Y, Ba and Cu. The films annealed at 940 °C had the c-axis oriented normal to the substrate surface and showed the superconducting properties with Tc(zero resistance) of 45 K.

Using atomic force microscopy and transmission electron microscopy, we examined the surface morphology of Bi-2223 superconducting thin films grown by metalorganic chemical vapor deposition, which is closely related to the growth mechanism of Bi-2223 films. As a result, we found an anisotropic in-plane growth. The growth rate along the a-axis is larger than that along the b-axis. Finally, we report on the fabrication of c-axis oriented Bi-2223 films with a roughness less than half a unit cell.

The purpose of this study was to investigate the mechanical properties of superelastic nickel-titanium orthodontic wires under controlled stress and temperature.Three different superelastic nickel-titanium wires were examined using differential scanning calorimetry (DSC), three-point bending test and micro X-ray diffraction (micro-XRD). The three-point bending test was carried out at constant temperature (23, 37 and 60 degrees C) and stepwise temperature changes (37-60 degrees C and to 37 degrees C) (37-2 degrees C and to 37 degrees C). Five specimens of each wire were tested. Micro-XRD spectra were measured at the tension side of the wire when the temperature changed from 37 to 60 degrees C or 2 degrees C.The load during the stepwise temperature changes (37-2 degrees C and to 37 degrees C) was consistent with that measured at a corresponding constant temperature. The micro XRD spectrum clearly showed that the austenite phase was transformed to martensite phase when the temperature is decreased from 37 to 2 degrees C. In a stepwise temperature change (37-60 degrees C and to 37 degrees C), the load became higher than the original load at each corresponding constant temperature. However, there was no detectable change in the micro-XRD spectrum when the temperature was increased from 37 to 60 degrees C.The superelastic nickel-titanium wires exhibited complicated and unexpected mechanical properties under stepwise temperature change. This study shows the possibility of qualitative analysis using micro-XRD to understand mechanical properties of these nickel-titanium wires.

成人鼠径ヘルニア修復術ではprosthesisを使用した術式が行われることが多くなった.しかしその長期的なQOLを検討した報告はほとんど認められない.われわれはprosthesisに対する炎症や組織の硬化が,術後長期間経過した後に,何らかの障害をきたしていないかどうかをアンケート調査を用いて検討した.対象は1998年1月から2000年11月までにメッシュプラグ法およびProlene™ hernia systemにより鼠径ヘルニア修復術を受けた症例とし, 1994年1月から1995年9月までの従来の術式による症例と比較した.この結果,尿意・便意を自覚した場合や排尿・排便時などの違和感,便秘や便柱の狭小化などの症状が,メッシュプラグ法術後に多く出現していた.以上より,長期経過としてメッシュプラグ法では挿入されたprosthesisによる臨床症状が出現する可能性があると考えられた.

症例は51歳の女性. 甲状腺クリーゼの診断で入院. 抗甲状腺薬, βブロッカーの内服, ビタミン剤を含まない電解質輸液を開始した. 入院後12日目より注視方向性眼振を供った眩暈が出現. 入院後33日目のMRI, T2強調画像にて中脳水道周囲に高信号を呈する病変を認め, 血中ビタミンB1値の低下がありWernicke脳症と診断された. 上部消化管内視鏡検査では幽門狭窄を来した進行胃癌を認めた. ビタミンB1大量投与により眩暈は改善し幽門側胃切除術を施行し退院した. 自験例は甲状腺クリーゼによる代謝亢進と, 輸液によるグルコースの負荷によりビタミンB1の需要が亢進したにもかかわらず幽門狭窄により摂取量が減少したことに起因したと推察された. また眼振を伴った眩暈は同症を疑う初発症状として重要で適切かつ迅速な対処をすべきであると考えられた. 同様の症例の報告は本邦および海外報告例にも認められずきわめてまれな症例と考えられた.

症例は70歳,女性.右下腹部痛を主訴に来院した.同部位に腫瘤を触知し,虫垂腫瘍が疑われ手術を施行.開腹所見では虫垂に腫瘍性病変や急性炎症所見は認められなかったが,大網が腫瘤状に取り巻いていたため,虫垂切除術および大網部分切除術を行った.腫瘤状の大網内には魚骨を認め,虫垂壁には組織学的に異物型巨細胞の出現を伴う慢性炎症所見が認められた.よって自験例の腹部腫瘤は虫垂を穿通した魚骨による大網の炎症性腫瘤と診断された.魚骨が虫垂に臨床的に問題となるような急性炎症をきたすことなく穿通し大網の炎症性腫瘤を形成した症例は稀であり,かつ自然閉鎖したと考えられる虫垂壁の組織学的変化を観察できたという点で自験例は興味深い症例と考えられた.同様の症例の報告はわれわれの検索した範囲では認められなかった.原因不明の腹腔内腫瘤症例では異物による炎症性腫瘤の存在を念頭におくことが過大手術を避けるためにも重要と考えられた.

The combined methodologies of fractography and laser-Raman spectroscopic analysis were used for evaluation of the resin-dentin bonds made with wet and dry bonding. Resin-dentin-bonded beams were produced by means of 2 acetone-based adhesives (One-Step and Prime & Bond NT). The microtensile bond test was conducted, and the fractured surfaces of all specimens were examined by SEM and an image analyzer. The amount of resin infiltration within the hybrid layer was quantified by means of a laser-Raman spectroscope. In Raman analysis, the amount of resin impregnation within the hybrid layer of the dry bonding was found to be significantly lower (approximately 50%) than that in the wet one. Under fractographic analysis, a correlation was found between the bond strength and the failure mode. Based on those findings, it was suggested that the integrity between the bonding resin and the top of the hybrid layer played a major role in bond strength.

We have demonstrated the operation of a CMOS inverter consisting of Si tunnel FinFETs. Both p- and n-type tunnel FinFETs are successfully fabricated and operated on the same SOI wafer. The current mismatch between p- and n-type tunnel FETs is compensated by tuning the number of fin channels. Very low short-circuit current and clear voltage input–output characteristics are obtained. The thin epitaxial channel in the tunnel FinFETs effectively increases the drain current and accordingly reduces the drain capacitance, which could help high-performance tunnel FET CMOS inverter operation.

We systematically investigated the bias temperature instability (BTI) of tunnel field-effect transistors (TFETs). The positive BTI and negative BTI mechanisms in TFETs are the same as those in metal–oxide–semiconductor FETs (MOSFETs). In TFETs, although traps are generated in high-k gate dielectrics by the bias stress and/or the interface state is degraded at the interfacial layer/channel interface, the threshold voltage (V th) shift due to BTI degradation is caused by the traps and/or the degradation of the interface state locating the band-to-band tunneling (BTBT) region near the source/gate edge. The BTI lifetime in n- and p-type TFETs is improved by applying a drain bias corresponding to the operation conditions.

The drain bias dependence of tunnel field-effect transistors (TFETs) is examined on the basis of the measured characteristics and device simulation to understand the electrical behavior of TFETs. Our analyses focus on the long-channel silicon-on-insulator (SOI)-based TFETs as a good basis for further studies of short-channel effects, scaling issues, and more complicated device structures, such as multigate or nanowire TFETs. By device simulation, it is revealed that the drain bias dependence of the transfer characteristics of the measured TFETs is governed by two physical mechanisms: the density of states (DOS) occupancy factor, which depends on drain-to-source bias voltage, and channel electrostatic potential, which is limited by the drain bias through strong carrier accumulation. These mechanisms differ from the drain-induced barrier lowering (DIBL) of metal–oxide–semiconductor field-effect-transistors (MOSFETs), and cause a significant impact even in long-channel SOIs. Finally, the obtained insights are successfully implemented in a TFET compact model.

We investigated the impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and the device performance of Ge fin field-effect transistors (Ge FinFETs). UV light irradiation during etching affected the shape of the Ge fin and the surface roughness of the Ge fin sidewall. A vertical and smooth Ge fin could be fabricated by neutral beam etching without UV light irradiation. The performances of Ge FinFETs fabricated by neutral beam etching were markedly improved as compared to those of Ge FinFETs fabricated by inductively coupled plasma etching, in which the UV light has an impact.

The positive bias temperature instability (PBTI) characteristics for n-type fin-channel tunnel FETs (TFETs) with high-k gate stacks have been thoroughly investigated and compared with conventional FinFETs. The subthreshold slope (SS) is not degraded at all while the threshold voltage (V th ) shifts in the positive direction by the PBTI stress. The activation energy of ?Vth for TFETs is almost the same as FinFETs, indicating that the PBTI mechanism for TFETs is almost the same as FinFETs. It was found that, by applying a positive bias to the n+-drain (normal operation condition), the PBTI lifetime is dramatically improved as compared with that in the conventional stress test (both the p+-source and n+-drain are grounded). This is because carrier injection from the n+-drain is the main cause of the PBTI, especially for n-type TFETs. Thus, the realistic impact of the PBTI is significantly mitigated for n-type TFETs.

Complementary (p- and n-type) tunnel FinFETs operating with subthreshold slopes (SSs) of less than 60 mV/decade and very low off-currents (on the order of a few pA/μm) have been experimentally realized on the Si CMOS platform. Improvements in the SSs have been realized by optimizing epitaxial channel growth on heavily arsenic- and boron-doped source surfaces for purging interface defects at the epitaxial tunnel junctions. By improving the interface quality, SSs of 58 and 56 mV/decade and on/off current ratios (ON/OFF) of 2 × 106 and 3 × 104 (with V D = |0.2| V) were respectively obtained for p- and n- tunnel FETs (TFETs) simultaneously.

The effectiveness of amorphous metal gate (MG) in suppressing low-frequency noise (LFN) for FinFETs has been thoroughly investigated. It was demonstrated that the amorphous TaSiN MGs with various atomic compositions provide flexible tuning of threshold voltage (V t ) as well as small V t variability, namely AVt. It was found that the TaSiN-MG FinFETs exhibit drastic reduction of LFN in comparison to the poly-crystalline TiN MG case. Modelling by 3D-TCAD reveals that work function variation (WFV) of the MG has a significant impact on LFN generation. Suppression of A Vt and LFN is highly beneficial to conduct further scaling of analog/digital components in SoC.

Three commercially available porcelains bonded to titanium were evaluated to determine the weakest zone of the titanium-porcelain bonding structures. Tensile bond tests were performed for these specimens (NO, DU, and VI) and for Ni-Cr alloy-porcelain bonding samples that served as controls. The maximum bond strengths between porcelain and titanium and the Ni-Cr alloy subjected to different metal surface treatments were compared. Sand blasting effectively increased bond strengths in titanium-porcelain bonding materials. No statistically significant differences in the maximum bond strengths were found between the NO sample and a control; however, sample NO exhibited greater maximum bond strength than DU and VI samples. The bond strengths increased with increasing area fractions of porcelain failure on fracture surfaces. The weakest zones were investigated based on the oxygen chemical states determined by electron spectroscopy for chemical analysis, which include bridging oxygen (Si-O-Si), nonbridging oxygen (Si-O(-) M(+)), and titanium oxide (O(2-)) states. We concluded that the titanium oxide layer is the weakest zone of titanium-porcelain bonding structures.