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This study was to elucidate the surface characteristics and in vitro cell behaviors of biomedical titanium (Ti) with the biofunctional surface (nanostructured rutile-Ti dioxide (NanoR-TiO2) layer combined with amino-groups (NH2) and albumin). Biofunctional surface features were analyzed via scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Immunolabeling with nano-gold particles was used to reflect the expected specific binding of protein on the biofunctional surface. In vitro cell behaviors were evaluated by culturing with mouse pre-osteoblastic cell line (MC3T3-E1) at 37 °C in different periods. Analytical results indicated that the sandwich-like (NH2/NanoR-TiO2/Ti) layer was formed on the Ti surface after plasma oxidation and polymerization. Immunolabeling analysis results also proved that the albumin can be successfully bonded with NH2 on NanoR-TiO2 layer. Moreover, cell morphology observation revealed that the biofunctional surface could potentially facilitate cell adhesion and proliferation. Therefore, the biomedical Ti with the biofunctional surface is a promising biomaterial for dental implant applications.

Display Omitted Triangular fin channel double-gate MOSFETs were fabricated on SOTB.A high threshold voltage shift was obtained in triangular fin devices.A smaller variability was confirmed in triangular fin devices by wet etching.Uniform line edges of a triangular fin were formed by wet etching.A damage-free BOX layer was obtained by the orientation dependent wet etching. Triangular fin (Tri-Fin) channel double-gate (DG) MOSFETs were successfully fabricated on (100) SOTB wafers using orientation dependent wet etching, and their electrical characteristics were systematically compared to the rectangular fin (Rec-Fin) ones by RIE. Thanks to the wide bottom area and the suppressed line edge roughness of Tri-Fins by the wet process, a higher threshold voltage (Vt) tunability and a smaller Vt variation were obtained as compared to the Rec-Fin ones. Moreover, the wet processed Tri-Fin devices provide a damage-free BOX layer, which is useful for the fabrication of multiple Vt devices with an ultrathin BOX layer.

We evaluate the impact of tunnel junction quality on the performance of tunnel field-effect transistors (TFETs). The interface between epitaxially grown channel and source surface was used as tunnel junctions. Performing a sequential surface cleaning procedure prior to epitaxial channel growth for heavily arsenic- and boron-doped Si surfaces improved the interface quality both for p- and n-TFETs. Simultaneously, the subthreshold swing (SS) values of the TFETs improved step-by-step with interface quality.

We investigated the impact of fin length ( T fin ) on the threshold voltage ( V th ) modulation by back bias ( V b ) for independent double-gate (IDG) tunnel fin field-effect transistors (tFinFETs). It was found that V th can be tuned by V b for IDG tFinFETs regardless of T fin , which can be explained by the back-gate-effect model of IDG FinFETs. For IDG tFinFETs, the slope (back-gate-effect factor ( γ )) of V th with respect to V b increases with thinning T fin . This means that T fin thinning is effective for tuning V th by V b for IDG tFinFETs. Furthermore, it was demonstrated that this back-bias-effect is consistent with the results of device simulation using an advanced nonlocal band-to-band model.

The performance of parallel electric field tunnel field-effect transistors (TFETs), in which band-to-band tunneling (BTBT) was initiated in-line to the gate electric field was evaluated. The TFET was fabricated by inserting an epitaxially-grown parallel-plate tunnel capacitor between heavily doped source wells and gate insulators. Analysis using a distributed-element circuit model indicated there should be a limit of the drain current caused by the self-voltage-drop effect in the ultrathin channel layer.

A simple chemical modification method was developed to immobilize cell-adhesive molecules on a titanium surface to improve its compatibility with human periodontal ligament cells (HPDLCs).The polished titanium disk was immersed in 1% (v/v) p-vinylbenzoic acid solution for 2 h to introduce carboxyl groups onto the surface. After rinsing with distilled deionized water, the titanium disk was dipped into 1.47% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide solution containing 0.1 mg/ml Gly-Arg-Gly-Asp-Ser (GRGDS), human plasma fibronectin (pFN), or type I collagen from calf skin (Col) to covalently immobilize the cell-adhesive molecules on the titanium surface via formation of peptide bonds. X-ray photoelectron spectroscopy analyses revealed that cell-adhesive molecules were successfully immobilized on the titanium surfaces. The Col-immobilized titanium surface revealed higher values regarding nano rough characteristics than the as-polished titanium surface under scanning probe microscopy. The number of HPDLCs attached to both the pFN- and Col-immobilized titanium surfaces was twice that attached to the as-polished titanium surfaces. The cells were larger with the cellular processes that stretched to a greater extent on the pFN- and Col-immobilized titanium surfaces than on the as-polished titanium surface (p < 0.05). HPDLCs on the Col-immobilized titanium surfaces showed more extensive expression of vinculin at the tips of cell projections and more contiguously along the cell outline than on the as-polished, GRGDS-immobilized and pFN-immobilized titanium surfaces. It was concluded that cell-adhesive molecules successfully immobilized on the titanium surface and improved the compatibility of the surface with HPDLCs. The Col-immobilized titanium surface could be used for forming ligament-like tissues around titanium dental implants.

We report on performance enhancement of FinFETs with a 25-nm-short extension of the source/drain by using atomic layer deposition (ALD) of SiO 2 thin films for the side-wall spacer (SWS) of the gate electrode. Recently, the higher parasitic resistance ( R para ) of the source/drain region due to the narrow fin width is one of the issues to be solved for the FinFET devices. In this study, the performance of the FinFETs has been successfully improved by the reduction of the parasitic resistance using the ALD-SWS.

Gate-induced drain leakage (GIDL) has become a crucial factor of determining current characteristics in ultra-small devices where the junction doping concentration is abruptly graded. It should be effectively suppressed for the low standby power operation (LSTP) of highly scaled metal–oxide–semiconductor field effect transistor (MOSFET) devices. In this work, the effects of doping profile on GIDL current are thoroughly investigated. In order to adjust the doping profile, we set up two variables: peak-to-gate edge distance and doping gradient. Underlap length can be also determined by the difference of these two variables. Based on analyses of the combinational effects of peak-to-gate distance and doping gradient, the methods of minimizing GIDL are searched for LSTP operation of silicon (SOI) FinFET on 32 nm technology node. The effective suppression of GIDL current can be achived by a number of combinations made by those two variables, rather than by a unique solution. 2-D and 3-D maps plotting the permissible pairs of variables will be given as the results by numerical simulations. Also, on the way to the aim, a quantitative method of extracting GIDL will be also introduced, which is more physically reasonable compared with existing one.

We propose a flex-pass-gate SRAM (Flex-PG SRAM), which is a FinFET-based SRAM to enhance both the read and write margins independently. The flip-flop in the Flex-PG SRAM consists of usual FinFETs, while its pass gates consist of double-“independent”-gate FinFETs, i.e., “four-terminal”- (4T-) FinFETs. A 4T-FinFET has a variable threshold voltage controlled by the second gate voltage. This function enables the Flex-PG SRAM to optimize the current drivability in the pass gates according to operational conditions of read and write. This results in enhancement of both the read and write margins. TCAD simulations revealed that the Flex-PG SRAM increases the read margin by 71 mV without the cell size penalty and decrease in the write margin, even when its 6 σ tolerance is ensured. Also, a half-cell experiment proved its feasibility.

This paper presents the fin-height controlled TiN-gate FinFET CMOS technology based on the experimental carrier mobility data. The good current matching by tuning the N-channel fin-height and the excellent transfer performance in the fabricated TiN-gate CMOS inverter are demonstrated. The developed technologies are attractive to materialize the high-performance FinFET CMOS circuits.

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.

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.

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.

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.

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.

To eliminate precipitates–segregates that can easily occur on the thin film surfaces of the multicomponent materials for electronics, a new approach is proposed, consisting of the following aspects: first , on the substrates, artificial steps of predefined height and width are produced, and second , films are grown on such substrates. The width of the step is taken equal to the ‘double of the migration length’ of the atomic species depositing on the substrate. In these conditions, precipitates migrate and gather at the step edges where the free energy is lowest and the resulting totally precipitate-free surface of the film on the step is suitable for device applications or integration purposes. The method has several other important advantages and they are discussed in the text. Using this new approach we present successful fabrication of a mesa structure showing intrinsic Josephson effect. We have used thin films of Bi-2212/Bi-2223 superstructure grown by MOCVD on (001) SrTiO 3 single crystal substrates with artificial steps of about 20 μm width.

In order to investigate the role of oxygen atoms in the Si(111)1 × 1−7 × 7 phase transition, the transition was examined accurately under extremely high vacuum conditions (< 4 × 10−10 Pa. Transition temperature was measured for the modified-FZ crystal (resisivity; 4 × 104 Ω cm) in which the oxygen concentration was 7.0 × 1015 atoms/cm3, and for a CZ crystal )resistivity: 5 Ω cm) which contained 6.4 × 1017 oxygen/cm3. The transition point was decided to be 1049 K for the modified-FZ crystal, and was lower than that for the CZ crystal by 40 K. By taking advantage of the modified-FZ in which the contribution of outdiffusion to the surface equilibrium oxygen concentration is expected to be quite low, the oxygen concentration in the surface region was controlled by quenching right after high temperature flashing and/or oxygen exposure. The transition temperature was changed depending on the oxygen concentration. These experimental facts indicate that the difference in the transition temperatures can be ascribed to the influence of oxygen concentration on the stability of the 7 × 7 structure.

We report on the successful preparation of intrinsic Josephson junctions on high-quality BSCCO thin films grown by MOCVD. The surface of as-grown films was very smooth with the roughness of the order of a half unit cell. Mesas were effectively structured on the grown films by the liquid-nitrogen-cooled dry etching method. A typical I–V characteristic in the c-axis direction of a BSCCO film shows the hysteresis and multiple resistive branches. The number of branches is consistent with that of junctions calculated from the height of a mesa structure. This indicates that BSCCO films consist of a series array of S(CuO2 layer)/I(SrO,BiO layers)/S(CuO2 layer) junction. The formation of stacked Josephson junctions was also confirmed by the temperature dependence and the magnetic field dependence of Ic.

We have succeeded in growing high-quality superconducting BSCCO films showing Tc(zero resistance) of 97K and Jc(77K; 0T and 1T) of 3.8×105 and 3.3×105A/cm2, respectively, without post-annealing by MOCVD, which are the highest Tc and the highest Jc among as-deposited BSCCO films reported so far. As-grown films also exhibited so small degradation of Jc that Jc(77K) was as high as 9.1×104A/cm2 even under the high magnetic field of 8T. Such high Jc values are first reported for BSCCO films in high magnetic fields (>1T). These films consist of a single high-Tc phase with the c-axis oriented perpendicular to substrate surface.