井上 尚三

In this study, we investigate the effects of focused ion beam (FIB)-induced damage and specimen size on the mechanical properties of Si nanowires (NWs) by a microelectromechanical system (MEMS)-based tensile testing technique. By an FIB fabrication technique, three types of Si NWs, which are as-FIB-fabricated, annealed, and FIB-implanted NWs, are prepared. A sacrificial-oxidized NW is also prepared to compare the mechanical properties of these FIB-based NWs. The quasi-static uniaxial tensile tests of all the NWs are conducted by scanning electron microscopy (SEM). The fabrication process and specimen size dependences on Young's modulus and fracture strength are observed. Annealing is effective for improving the Young's modulus of the FIB-damaged Si. Transmission electron microscopy (TEM) suggests that the mechanism behind the process dependence on the mechanical characteristics is related to the crystallinity of the FIB-damaged portion. (C) 2017 The Japan Society of Applied Physics

This paper describes a plastic reshaping technique for Si thin membranes by using focused ion beam (FIB) processing. FIB is used to locally pattern and implant Ga ions into the membranes. The combination of Ga ion doping and alkali wet etching enables us to fabricate nanometer-thick Ga-ion-doped amorphous Si membranes, which can be bent upward at arbitrary angle by controlling the FIB beam irradiation condition. The bending mechanism is discussed in the light of Ga ions implanted depth from the membrane surface. By using this technique, a micrometer-sized chute structure with several different angles is produced. (C) 2016 The Japan Society of Applied Physics

In this paper, precise control of the shape, size, and porosity of porous silica submicron particles and their strength evaluation are described. Self-organization phenomenon of silica nanopowders and submicron polystyrene latex (PSL) balls in an atomized mist is used for the fabrication of the particles. When temperatures of lower-and upper-zone heaters are 100 and 600 degrees C, and N-2 gas flow rate is 0.4 l/min, spherical particles are produced. When PSL concentration increases, the number of pores increases. Particles with uniformly-arranged pores are produced at the PSL concentration of around 3wt%. By using the PSL balls of different diameters, porous silica particles including different size pores are made. Also, compressive fracture test is conducted to check the effect of vacuum annealing on the strength of particles. The annealed particle shows higher fracture force than the unannealed particle, which indicates that the annealing would be effective for improving the mechanical reliability. (C) 2016 The Japan Society of Applied Physics

In this paper, we describe the influence of 700 degrees C vacuum annealing on strength and fracture behavior of micro-and nano-scale Si structures fabricated by focused ion beam (FIB). Si nanowires (NWs) made from silicon-on-nothing (SON) membrane are fabricated using FIB. Microscale Si specimens are fabricated by conventional micromachining technologies and FIB. These specimens are tensioned to failure using specially developed microelectromechanical systems (MEMS) device and thin-film tensile tester, respectively. The mean fracture strengths of the nano-and microscale specimens are 5.6 and 1.6 GPa, respectively, which decrease to 2.9 and 0.9GPa after vacuum annealing at 700 degrees C for only 10 s. These strength values do not vary with increasing annealing time. Fracture origin and its behavior are discussed in the light of fracture surface and FIB damage layer observations. (C) 2016 The Japan Society of Applied Physics

In this paper, the influences of specimen size and test temperature on the viscoelastic properties of SU-8 photoresist films are described. Films with the thicknesses of 1 mu m and 10 mu m are subjected to quasi-static uniaxial tensile tests and stress relaxation tests at temperatures ranging from 293K to 473 K. The average glassy modulus at 293K is 3.2 GPa, which decreases with an increase in the test temperature irrespective of specimen size. The mean fracture strain depends on film thickness as well as temperature. The fracture strain of the 1-mu m thick films is approximately half of that of the 10-mu m thick films at each temperature. Stress relaxation tests are conducted for constructing the master curves of the relaxation moduli. There is no apparent thickness dependence on the master curve. Above glass transition temperature, T-g, apparent activation energies for the two films are almost identical, whereas the activation energy for the thinner films is smaller than that for the thicker films below T-g. This size effect is discussed using Fourier transform infrared spectroscopy (FTIR).

In this paper, the effect of vacuum annealing on the mechanical properties of Au bonding wires is described. Au bonding wires with a diameter of 25 mu m are subjected to quasi-static uniaxial tensile tests in laboratory air. The bonding wire specimens are prepared by attaching a wire to a Si frame fabricated by deep reactive ion etching (DRIE). The mean Young's modulus and 0.2% offset yield strength are 114 GPa and 354 MPa, respectively. By annealing at 100-300 degrees C for 10 min in vacuum, Young's modulus gradually decreases with increasing annealing temperature, whereas yield strength rapidly decreases in the annealed wires at temperatures above 200 degrees C. The annealing effect is discussed on the basis of the change in the number of recrystallized grains in the wires.

In this study, for the practical use of reactively alloyed NiAl as a structural material, its mechanical reliability is evaluated. An Al/Ni multilayer film is attractive as a local heat source for soldering. To investigate the difference in mechanical characteristics between as-deposited Al/Ni multilayer films and reactively alloyed NiAl films, quasistatic uniaxial tensile tests and stress relaxation tests were conducted. A higher Young's modulus and a higher strength were obtained in the NiAl films. The films also showed better consistency under a constant applied strain. Then, four-point bending tests were carried out to examine the fracture strength of reactively bonded solder joints and to specify the fracture origin. All the joints fractured at the interface of the SnAg solder layer and the reactively alloyed NiAl layer. The durability of the reactively alloyed NiAl in the joints is discussed in the light of the grain size evaluated by electron backscatter diffraction (EBSD) analysis.

In this paper, the design and development of an electrostatically actuated micro electromechanical systems (MEMS) device for the tensile test of Si nanowires (NWs) are described. The device is composed of a comb-drive electrostatic actuator for generating uniaxial tensile force, capacitive sensors for measuring tensile force and displacement, an electrothermal actuator with a ratchet for clamping and releasing a sample stage, and a force calibration mechanism. The resolution of the tensile elongation measurement is 1 nm, determined by a resolution of 0.1 fF on an LCR meter. The tensile force is derived from the displacement and the spring constant of the support beams of the driven sensor. The theoretical resolution of tensile force measurements ranges from 10 to 263 nN, depending on the stiffness of the specimen. Electrical insulating structures for minimizing electrical signal noise are designed to accurately measure the capacitance change of the two capacitive sensors. To demonstrate these possibilities, Si NWs fabricated using a focused ion beam (FIB) were characterized using a scanning electron microscope (SEM). The Young's modulus and fracture strength were 127.7 and 5.4 GPa, respectively, indicating that FIB damage affects these mechanical characteristics.

Self-propagating exothermic reaction bonding (SERB) technique with Al/Ni multilayer film is fascinating in the viewpoint of lots of outstanding features, such as atmosphere-independent exothermic reaction and its self-propagation. The reactively bonded solder joints with high bonded strength are required for practical use in semiconductor devices. We have investigated the fracture strength of rectangular-solid specimens with reactively bonded solder joint (Sn-3.5Ag solder/reacted NiAl/Sn-3.5Ag solder) sandwiched by single crystal silicon (SCS). In this paper, the influence of bonding atmosphere on the fracture behavior is discussed by means of four-point bending testing and fracture surface observation. The fracture strength increases with increasing pressure load during bonding. The strength of the vacuum-bonded specimens is found to be higher than that of the air-bonded specimens. The fracture surface observation results suggest that Al oxide and intermetallic compounds (IMCs) formed at the reacted NiAl layer and the SnAg solder layer, respectively, would have affected the strength of the Al/Ni SERB joints.

Siの代替素材として注目されているワイドギャップ半導体のMEMS・NEMS適応サイズでの機械物性は未知なところが多い．本研究では，独自開発したMEMS引張試験技術を用い，3C-SiC薄膜からFIBサンプリングしたSiCナノワイヤに対して引張試験を行った．結果，ヤング率および破壊強度はそれぞれ288.5GPa，10GPaであった．ヤング率はSiC公称値より36％程度低かった．ナノインデンテーション試験結果と併せてFIBのダメージ層の影響を議論する．

This paper describes Si plastic reshaping technique, Si origami, by combining focused ion beam (FIB) processing and wet etching. FIB is used as a nano tool for local etching as well as Ga ion implantation. The combination of Ga ion doping and alkali wet etching to a Si wafer enable us to fabricate a nanometer-thick Ga-ion-doped amorphous Si membrane, which can be bent to upward/downward at arbitrary angle by controlling FIB beam irradiation condition. The bending mechanism is discussed in the light of doped Ga ion distribution and collision cascade effect. The Si origami technique allows us to manufacture a micron-sized Si 3D structure like an airplane from a Si nano-membrane.

This paper reports on the precise control of the shape, size, and porosity of porous silica nanoparticles by using the atomized heating method. Self-assembly phenomenon of silica nanopowders and submicron polystyrene latex (PSL) balls was used for the fabrication. At the PSL concentration of around 3wt%, pores were uniformly arranged in sphere nanoparticles. By vacuum annealing at 1200 degrees C for 30min, surface modification of the nanoparticles could be realized. The produced porous silica nanoparticles were subjected to strength test with a MEMS-based force sensor in a SEM. The annealed nanoparticles showed higher fracture strength by three times than the unannealed nanoparticles. Vacuum annealing would be effective as post-process for strengthening porous silica nanoparticles.

Reactively bonded solder joints with Al/Ni exothermic films attract much attention in semiconductor and microelectromechanical systems (MEMS) industries. Higher bond strength of the joints is required for long-term mechanical reliability. We have investigated the strength of rectangular-solid single crystal silicon (SCS) specimens with reactively bonded Sn-3.5Ag solder joint by using specially developed four-point bending test equipment. In this paper, the influences of Al/Ni exothermic film thickness and metallic interlayer on the strength are discussed. The strength increases with increasing Al/Ni film thickness and pressure load during bonding. Metallic interlayer between the solder and SCS also affects the strength because fracture origin is dependent on the types of metals. The obtained results suggest that reacted NiAl is durable against external forces compared with the solder and interlayer.

Metallic glass alloy can be a promising structural material for MEMS application because of its superior properties. However, there was limited information on fabrication and properties of thin metallic glass films. This paper reports the metallic glass film deposited by rf magnetron sputtering using a Zr₆₅Cu_17.5Ni₁₀Al_7.5 alloy target. Although the composition of as-deposited films changes along with the substrate position, it was found that films grew with relatively uniform composition at the substrate holder center facing within the target erosion circle. Ar pressure also affected the film composition. Residual stress of deposited films changes from compressive to tensile with increasing Ar pressure as crystalline metallic films did. Tensile fracture stress of deposited films rapidly decreased when the Ar pressure was higher than 0.7Pa, while the microhardness of deposited films were ∼6GPa regardless of Ar pressure. The deposited films showed glass transition behavior and the ability of micro-molding.

我々は、これまで熱分解BNターゲットを高周波スパッタしてc-BN薄膜を成長させることを試みてきている。系統的に成膜条件を変化させて実験を行った結果、スパッタガスとして純Arを用いた場合とAr+N2混合ガスを用いた場合でc-BNの成長する条件が大きく異なることを見出した。本報告では、それらの結果を示しながら、スパッタガス種が及ぼす影響について検討する。

軽金属と遷移金属をナノの厚みで積層堆積させた多層膜は，外部刺激導入により化合物生成に伴う発熱反応を生じる．成膜条件で発熱性能を制御でき，ある条件では0.1秒に1000°C昇温可能である．このような自己伝播発熱機能をナノ～マイクロサイズの微粒子に付与することができれば，アプリケーションの広がりが期待できる．本講演では，著者らがこれまで開発してきた2種類のAl/Ni発熱微粒子製造技術を紹介するとともに，作製した微粒子の発熱性能について述べる．

本研究では，NEMSを構成するナノスケール構造体の機械特性定量評価を目的として，SEM内で引張試験を実施する技術を開発した．FIB加工と高真空アニールにより作製したSiナノワイヤの引張試験を行い，FIBダメージとアニールが機械物性に及ぼす影響を評価した．また，アニール前後の試験片のTEM観察を行い，アニールによるダメージ層の再結晶化やGaナノクラスターの形成から排出に至るまでのメカニズムを考察した．

In this paper, the effect of high-vacuum annealing with crystallinity-damage recovery on mechanical characteristics of Ga-implanted Si nanowires (NWs) fabricated by focused ion beam (FIB) is described. We have specially designed and developed "Beetle-like" tensile test device, presented for the first time, enables us to directly tension 10 similar to 200 nm-wide Si NWs with high precision. Also, we have established the test technique to perform the tensile testing with in-situ observation in a field-emission scanning electron microscope (FE-SEM), which has the displacement measurement system by a digital image correlation using SEM image. In addition, "Cassette-type" sample preparation technique for Si NWs made from silicon on nothing (SON) membrane is contrived for annealing at 700 degrees C in high-vacuum. After the annealing, Si NWs were sampled to the device without FIB observation, and tensile tested. The Young's modulus gradually recovers with increasing annealing time, whereas the strength drops first at 10 sec annealing and then slightly increases with annealing time. The difference in recovering process between these characteristics is discussed from the viewpoint of crystallinity recovery and Ga-nanocluster generation & annihilation.

In this paper, a new technique for fabricating self-propagating explosive Al/Ni flakes is described. Al/Ni multilayer films showing self-propagating exothermic reaction are deposited by dual-source dc sputtering onto a mesh substrate made of nylon. After the deposition, the films are removed as the flakes from the substrate by folding and rubbing the nylon against itself in water. The flakes' heat energy is compared with the films' heat energy by means of differential scanning calorimetry. Reaction propagation velocity of the flakes evaluated using a high-speed camera is also compared with the velocity of the films. (C) 2014 The Japan Society of Applied Physics

We discuss the possibility of WC-Co cemented carbide as structural material in MEMS. The cemented carbide is typically used as material for working tool because it has superior characteristics, such as very high Young's modulus, excellent rigidity, good chemical inertness, and good thermal stability. These are also attractive for mechanical elements in MEMS. We investigate the influences of specimen size and WC-Co composition ratio on mechanical properties of FIB-fabricated WC-Co cemented carbide nanowires by means of on-chip uniaxial tensile testing in FE-SEM. It is presented that Co binder size dependency on the Young's modulus and fracture strength has been obtained.

This paper describes the effects of specimen size, focused ion beam (FIB) induced damage, and annealing on the mechanical properties of sub-100nm-sized silicon (Si) nanowires (NWs) that were evaluated by means of uniaxial tensile testing. Si NWs were made from silicon-on-nothing membranes that were produced by deep reactive ion etching trench fabrication and ultra-high vacuum (UHV) annealing. FIB system's probe manipulation and film deposition functions were used to fabricate Si NWs and to directly bond them onto the sample stage of a tensile test device. The mean Young's modulus and the mean strength of FM-damaged NWs were 131.0 GPa and 5.6 GPa, respectively. After 700 degrees C and 1000 degrees C annealing in UHV, the mean Young's modulus was increased to 168.1 GPa and 169.4 GPa, respectively, due to recrystallization by annealing. However, the mean strength was decreased to 4.1 GPa and 4.0 GPa, respectively. These experimental facts imply that the crystallinity of NWs improved, but the morphology was degraded. The surface degradation was probably related to gallium ion implantation into NWs surface during FIB fabrication.

In this paper, the influence of thermal annealing on the elastic-plastic behavior of Al-Si-Cu films under uniaxial and biaxial tensile stress states is described. For the mechanical evaluation of the films, we used an in-plane biaxial tensile test equipment that was specially designed and developed. In the uniaxial tensile test in which the strain rate was varied from 4.0 x 10(-4) to 5.0x10(-3) s(-1), annealing at 623K (350 degrees C) in N-2 gas for 1 h did not affect the Young's modulus. The mean value was found to be 64.5 +/- 5.6GPa. The yield strength showed annealing dependency. The mean yield strength was 168.5 +/- 2.2GPa and 128.1 +/- 9.7GPa for as-deposited and annealed films, respectively. In the biaxial tensile test in which the strain rate ratio was changed between 1: 1 and 1: 5 in Cartesian coordinates, tensile force and displacement were well controlled. The stresses at the time of yielding were fitted well using the yield equation of Hill with different Lankford coefficient values. X-ray diffraction and electron backscatter diffraction (EBSD) analyses demonstrated that the films had a < 1 1 1> fiber texture. The grain growth and sharpening of the texture with annealing were observed in the EBSD analysis. Auger electron spectroscopy analysis suggested that a reduction in yield strength after annealing was related to Cu segregation at the grain boundaries, in addition to grain growth during annealing.

A novel method of preparing a large number of fiber-shaped Ni-Ti nano crystals with medium aspect ratio in the order of 10 was examined. A target of nickel-titanium shape memory alloy was sputter-deposited on a porous alumina membrane having holes with 200 nm diameter in average. The porous geometry of the substrate caused the growth of columnar structure under the sputtering conditions, the argon gas pressure of 0.2 Pa and the substrate temperature of 2500 degrees C, which would provide homogeneous alloy films, if the surface of substrate was flat. The columnar structure thus obtained was the assemble of isolated columns which were weakly adhered with each others, and could be separated into individual ones by applying ultrasonic vibration. Each column had a fibrous shape of diameter about 200 nm and 2.5 mu m long (the aspect ratio was 12.5). The crystals can exhibit both martensitic transformation and the R-phase change with the total amount of latent heat 18 J g(-1), indicating that 75% of the nano crystals was active to these transformations. (C) 2012 Elsevier B.V. All rights reserved.

In this paper, we describe an experimental technique to achieve a highly reliable characterization of the mechanical properties of silicon (Si) nanowires (NWs). A reusable on-chip Si device consisting of comb-drive electrostatic actuator for generating tensile force and capacitive sensors for measuring tensile force and displacement was designed and developed for quasi-static tensile test of Si NWs. The combination of focused ion beam (FIB) fabrication, FIB-assisted chemical vapor deposition, and probe manipulation enabled us to directly fabricate the NWs on the device. This sampling technique led to high yielding percentage of nano-scale tensile testing. The NWs were made from 200-nm-thick Si membranes that were produced by using silicon-on-nothing membrane fabrication technique. Several Si NWs were annealed at 700 degrees C in ultrahigh vacuum (UHV) for 5 min in order to examine the influence of annealing on the mechanical characteristics. The mean Young's modulus for nonannealed NWs was 129.1 +/- 10.1 GPa. After UHV annealing, the mean value was improved to be 168.1 +/- 1.3 GPa, comparable to the ideal value for Si(001)[110]. The annealing process gave rise to improving the Young's modulus, whereas it degraded the strength. Transmission electron microscopy suggested that recrystallization and gallium nanoclusters formation by annealing would have changed the mechanical characteristics. (C) 2013 The Japan Society of Applied Physics

In this paper, the influences of pretreatment and hard baking on the mechanical characteristics of SU-8 microstructures are described. Four types of samples with different combinations of O-2 plasma ashing, primer coating and hard baking were prepared for shear strength tests and uniaxial tensile tests. Specially developed shear test equipment was used to experimentally measure the shear adhesion strength of SU-8 micro posts on a glass substrate. The adhesiveness was strengthened by hard baking at 200 degrees C for 60 min, whereas other pretreatment processes hardly affected the strength. The pretreatment and hard baking effects on the adhesive strength were compared with those on the fracture strength measured by uniaxial tensile testing. There were no influences of O-2 plasma ashing on both the strengths, and primer coating affected only tensile strength. The primer coating effect as well as the hard baking effect on stress relaxation phenomena in uniaxial tension was observed as well. Fourier transform infrared spectroscopy demonstrated that surface degradation and epoxide-ring opening polymerization would have given rise to the primer coating effect and the hard baking effect on the mechanical characteristics, respectively.

We have investigated the effects of bias voltage and substrate temperature on the growth process of RF-magnetron-sputtered BN films. When the negative bias voltage was higher than 80 V, films including the sp3-BN phase grew even if the substrate temperature was RT. When the substrate temperature and the negative bias voltage were 600 °C and &gt 100 V, respectively, films containing more than 90% sp3-BN phase were grown. The growth process of films deposited at 150 and 600 °C under a constant bias voltage of -100 V was studied by Near edge X-ray absorption fine structure (NEXAFS) measurements. These films consisted of two layers: an sp2-BN phase underlayer and an sp 3-BN phase top layer. The sp2-BN underlayer had a preferential orientation of the c-axis parallel to the film surface. The thickness of the sp2-BN underlayer decreased with increasing substrate temperature. High substrate temperatures assisted the nucleation and growth of the sp3-BN phase. © 2013 The Japan Society of Applied Physics.

We have been studying the surface discharge plasma generated by insulating capillary tube as an ablation gun for depositing diamond-like carbon films. It is found in our series of experiments that applying a positive voltage to the gun of the system allows us to fill the entire chamber with plasma. In this study, we propose a new application of the surface discharge technique for plasma nitriding of steel.<br>Nitriding experiments under various temperatures were carried out for SKH51 high speed steel substrate. The hardness of the specimen nitrided at 500°C was the highest in this work. Nitriding depth of the specimen seemed to be more than 40μm. Although X-ray diffraction measurements showed no distinguishable nitride diffraction peaks, the hard X-ray photoelectron spectroscopy (HXPS) measurements suggested the presence of Cr-N and W-N chemical bonds in the nitrided SKH51 steel. Furthermore, so-called "white layer (Fe_2-3N)" or damage were not found on the surface of nitrided specimens. It can be concluded that this technique can be one of the most superior techniques for nitriding steel.

In this paper, the effect of surface damage induced by focused ion beam (FIB) fabrication on the mechanical properties of silicon (Si) nanowires (NWs) was investigated. Uniaxial tensile testing of the NWs was performed using a reusable on-chip tensile test device with 1000 pairs of comb structures working as an electrostatic force actuator, a capacitive displacement sensor, and a force sensor. Si NWs were made from silicon-on-nothing (SON) membranes that were produced by deep reactive ion etching hole fabrication and ultrahigh vacuum annealing. Micro probe manipulation and film deposition functions in a FIB system were used to bond SON membranes to the device's sample stage and then to directly fabricate Si NWs on the device. All the NWs showed brittle fracture in ambient air. The Young's modulus of 57 nm-wide NW was 107.4 GPa, which was increased to 144.2 GPa with increasing tH.W.dth to 221 nm. The fracture strength ranged from 3.9 GPa to 7.3 GPa. By assuming the thickness of FIB-induced damage layer, the Young's modulus of the layer was estimated to be 96.2 GPa, which was in good agreement with the literature value for amorphous Si. Copyright © 2013 by ASME.

In this article, the development of quasi-static tension-torsion combined loading test equipment for a microscale beam specimen is described. The equipment is composed of a piezoelectric actuator in actuator case for uniaxial tensile loading, a load cell for measuring X-Y-Z-axes forces and-axis torque, a stepping motor for rotating sample stage, X-Y-Z-stages for alignment, and a CCD camera for measuring tensile elongation using original image analysis software. The shape and dimension of all the mechanical jigs were designed by means of finite element analysis (FEA). The tension and torsion loading systems are able to be individually operated, so that uniaxial tension, pure torsion, and combined tension-torsion loadings can be realized. The specimen that was designed in consideration of typical optical microelectromechanical systems (MEMS) devices consists of a mirror plate supported by two microbeam structures, four springs, and a frame with chucking holes. Single crystal silicon (SCS) specimens were fabricated by deep reactive ion etching (DRIE). It was confirmed that the above-described three types of loadings were able to be successfully applied to the beam specimens. All the specimens fractured in a brittle manner and showed different-shape fracture surfaces under different deformation modes. © 2013 by ASME.

We have been studying the Pulsed Plasma Deposition (PPD) technique for applying Diamond-Like Carbon film deposition. This technique is one of the applications of the surface discharge, and the deposition process is based on an ablation. In this technique, pulsed electron and plasma beams irradiate the target through the discharge tube and make plume on the target. Ablated particles from the target are deposited as the thin films on the substrate. Until now, this technique has not yet been applied to produce the DLC film. We have tried to apply this technique without using an intermediate layer of a metal thin films and without heating the substrate to grow the DLC films with higher hardness and quality. As a result, when the discharge voltage has been applying at -13kV, hardness of deposited the DLC films was measured to be about 90GPa, sp3-contents of the DLC films was measured to be 80% by NEXAFS, surface of the DLC films was observed to be smooth by FE-SEM and adhesion to the substrate was about 80N. We conclude from the above results that the PPD technique can be one of the superior technique for producing DLC films with high hardness, smooth surface and high adhesion.

本研究では，合金ターゲットを用いたスパッタ法によって成長させたZrCuNiAl薄膜の機械的特性を調査した．その結果，成膜条件による薄膜のモルフォロジーの変化にともなって硬さ，ヤング率，引張り強度などの機械特性も変化することが明らかとなった．現在，成膜条件がガラス転移挙動に及ぼす影響について調査中であり，ガラス転移が生じる温度域での微細加工についても検討する予定である．

スパッタ中の基板に降り注ぐイオンの量とエネルギーは、マグネトロン周囲に巻いたコイルの電流や基板バイアス電圧によって制御できる。これらを変化させてBN薄膜を成長させた結果、どちらも薄膜のc-BN相含有率に影響を及ぼすことがわかった。また、基板そのものもc-BN相の含有率に影響があり、超硬合金基板上でc-BN相が生成する条件はSi基板に比べてより高エネルギー側にシフトすることも明らかとなった。

本研究は，安定した自己伝播発熱反応を生じるNiフリー材料の探索を目的としている．今回はTi-Si多層薄膜に着目し，種々のTi:Si膜厚比を持つ多層薄膜を作製して自己伝播発熱反応を観察した．その結果，Ti:Si=5:4の組成を持つ多層薄膜は，非常に良好な自己伝播反応を示すことを見出した．また，Ti-Si多層薄膜の反応開始に必要な総膜厚はNi-Al多層薄膜よりむしろ薄く，ナノ発熱材料として期待できることがわかった．

In this paper, tension-torsion-bending combined loading test technique for microscale single crystal silicon beam specimens is described. We have designed and developed two types of the multi-deformation loading test apparatuses to investigate the deformation-mode and specimen-size dependencies on the fracture strength. The comparisons among the strength data under different deformation-modes and different sizes were made using the Weibull statistics. Both of the size effect and the deformation-mode effect were apparently found when all the strength data were calculated based on the assumption that the specimens had ideal flat sidewalls. Stress concentration factors (SCFs) in each specimen were estimated using scanning electron microscopy observation and finite element analysis. After re-calculation of all the strength data in consideration of the SCFs, the Weibull distribution showed no deformation-mode effect though size effect still remained. © 2013 IEEE.

This paper describes the effects of specimen size, focused ion beam (FIB) damage, and annealing on the mechanical properties of sub-100nm-size silicon (Si) nanowires (NWs) evaluated by direct tensile testing. Si NWs were made from silicon-on-nothing (SON) membranes that were produced by deep reactive ion etching (DRIE) trench fabrication and ultra-high vacuum (UHV) annealing. FIB system's probe manipulation and film deposition functions were used to fabricate Si NWs and to directly bond them onto the sample stage of a tensile test device. The mean Young's modulus and strength of FIB-damaged NWs were found to be 131.0GPa and 5.6GPa, respectively. After 1000 degrees C annealing in UHV, the Young's modulus was increased to 169.2GPa, whereas the strength was decreased due to morphology degradation. The combination of FIB system's sampling and UHV annealing will enable us to challenge accurate evaluation of 10nmx10nm cross-sectional Si NWs and to obtain true size effect (without process effect) on the mechanical characteristics in near future.

In this article, the quasistatic and dynamic tensile properties of aluminum-silicon-copper (Al-Si-Cu) alloy films are described. The films were deposited by sputtering onto thermally oxidized Si wafers, and then half of the wafers were heat treated at 623 K in nitrogen gas for 1 h. Specially developed environment-controlled uniaxial tensile test equipment was used to carry out the quasistatic tensile test, stress relaxation test, and cyclic loading test at temperatures ranging from room temperature (RT) to 573 K in high vacuum, and the influence of annealing on the mechanical characteristics was investigated. The Young's modulus did not show annealing dependency. The mean value was 65 GPa at RT, and gradually decreased with increasing test temperature. The yield stresses of nonannealed and annealed films were 168.5 and 129.6 MPa, respectively, which also decreased with temperature rise. In stress relaxation test results, creep exponents in respective films were obtained from curve fitting using the Norton law, which indicated that creep deformation was restricted by annealing. The cyclic loading test was performed under stress- and displacement-amplitude-constant modes. The stress-amplitude-constant mode test provided creep deformation acceleration to failure, whereas the displacement-amplitude-constant mode test showed a gradual drop of stress amplitude. The stress-amplitude change was compared with stress relaxation curves; consequently, the creep deformation was dominant to the degradation of Al-Si-Cu films subjected to cycling loading with constant displacement amplitude. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4711040]

In this article, the mechanical and electrical characteristics of co-sputtered W-Mo thin films investigated for the application to microelectromechanical systems are described. W-Mo thin films with various compositions were deposited by co-sputtering onto a cover glass and silicon oxide (SiO (x) ) film-coated Si wafer. The internal stress measured by Newton-ring method depended on film composition and Ar pressure, but were independent on annealing at 623 K. The hardness gradually decreased with an increase in Ar pressure, whereas the effective Young's modulus stayed constant throughout Ar pressures ranging from 0.2 to 0.4 Pa. Both the mechanical properties showed no dependences of film composition and annealing. The resistivity was proportional to Ar pressure, but was not related to film composition. Annealing slightly affected the resistivity. Auger spectroscopy clarified that, by annealing, an oxide layer of approximately 10 nm thick was produced on the top surface, but film composition did not change. From the experimental results obtained, annealing at 623 K did not affect the mechanical and electrical properties of W-Mo films. This indicates that the co-sputtered film is very stable at temperatures ranging from RT to 623 K. By controlling Ar pressure, stress-free W-Mo films with superior mechanical characteristics and low resistivity can be produced regardless of film composition.

In this article, a new materials test technique for a micron-size beam specimen is described. We have designed and developed the materials test equipment. The specimen that was designed in consideration of a microelectromechanical systems mirror device consists of a mirror, two torsion beams, and a frame. The specimen was made of single crystal silicon fabricated by deep reactive ion etching. The combination of loading point and with or without rotation support enables us to carry out three different types of material tests that are pure torsion, torsion-bending combination, and doubly-clamped beam bending tests. The fracture strength was measured, and the influence of deformation modes on the strength was discussed.

The purpose of this work is to establish a deposition process of Ti-Ni-Cu films showing shape memory effect in the as-deposited state. 5-mu m-thick Ti50Ni35Cu15 films have been deposited onto thermally oxidized (001) Si wafer by triple-source dc magnetron sputtering at various substrate temperatures. Their shape memory behavior were characterized by XRD, DSC measurements and thermal cycling tests under various constant tensile stresses. We have confirmed that crystalline films can be grown directly when the substrate temperature exceeds 400 degrees C. The films deposited at higher than 450 degrees C showed thermoelastic martensitic transformation and their M-s temperature slightly increased with increasing substrate temperature. Since their M-s temperature were found to be higher than 30 degrees C, they can be used as an actuator at RT. These films were also found to have higher critical stress against plastic deformation than the post-deposition crystallized films. We have also tried to fabricate a prototype of micro-actuator and to characterize their actuation behavior and have confirmed that TiNiCu/SiO2 double layered diaphragm showed an actuation response to a pulsed current of more than 100Hz.