神田 一浩

The spin-coated ITO film can be delineated by room-temperature nanoimprint lithography (RT-NIL), but the patterns disappeared after 200 degrees C annealing process. To overcome the above problem, we examined 254 nm UV irradiation effect onto a spin-coated ITO film. However, this result suggests that UV irradiated pattern shrink in size. In this paper, we confirmed UV irradiation effect on pattern shrinkage of sol-gel ITO replicated by RT-NIL.

Molecular orientation in a photo-crosslinkable liquid crystalline polymer (PLCP) film was explored by a thermal nanoinprinting technique using a SiO(2)/Si mold with a line-and-space (L&S) pattern. A molecular oriented structure was confirmed by polarization optical microscopy and diffraction efficiency measurements, at which the reoriented direction was parallel to the mold lines. We demonstrated thermal nanoimprinting on prealigned PLCP films by linearly polarized UV (LPUV) and evaluated the optical characteristics of imprinted PLCP films. As a result, the prealigned PLCP films were reoriented by thermal nanoimprinting. (C) 2010 The Japan Society of Applied Physics

We investigated low-temperature crystallization of a-Ge, a-Si and a-SiGe films by the SR soft X-ray irradiation at storage ring current of 25-220 mA and dose quantity of 50 mA . h. The relationship between electron excitation-atom movement process, thermal process and the storage ring current are investigated.

The authors report the first room-temperature nanoimprint lithography (RT-NIL) process using sol-gel indium tin oxide (ITO) as a replicated material. The spin-coated ITO film has to be annealed over 600 degrees C to obtain a low resistivity. The spin-coated ITO film can be delineated by RT-NIL, but the patterns disappear after annealing at 200 degrees C. To overcome the above problem, they examined UV irradiation effects on a spin-coated ITO film. As a result, they found that the ITO patterns imprinted by RT-NIL stayed the same after being annealed at 600 degrees C for 1 h due to 254 nm UV irradiation before annealing.

We performed a nanostructure analysis of diamond-like carbon (DLC) nanowires used to compose nanosprings fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). The DLC nanowires of the as-grown nanosprings had elastic double structures, in which a 50-nm-diameter core containing 3-at. % gallium (Ga) in addition to carbon (C) was enclosed in an outer 25-nm-wide DLC shell. The Young's modulus of the core was 322 GPa, approximately 12 times that (26 GPa) of the DLC shell. Energy dispersion X-ray spectroscopy (EDX) revealed that the C densities of the core and the shell were similar, indicating that the density of the core was higher than that of the shell owing to the incorporation of Ga into the core. However, the core density was approximately halved by 800 °C annealing. This is attributed to the vaporization of Ga and the movement of C from the core to the shell.

We investigated the characteristics of a-Si film with thicknesses of 1 and 50 nm those were irradiated by soft X-ray from the undulator source. The cohesion of Si atoms were observed after X-ray irradiation for 1 nm-thick a-Si, but it was not observed for 50 nm-thick a-Si. The average roughness Ra of 1 nm-thick-Si film were changed from 0.63 to 1.7 nm by soft X-ray irradiation. The electric resistivity of it also increased corresponding to the change of the surface roughness. Although the TO phonon peak was not observed for 1 nm-thick a-Si, it was observed for 50 mu-thick a-Si. For these phenomena, the mechanism that the electron excitation by photon becomes the trigger of the cohesion was discussed.

Nanoimprint lithography (NIL) is very useful for mass-producing nanostructure devices at a low cost and a high throughput. To avoid the adhesion of replication materials, NIL molds are usually coated with an antisticking fluorinated self-assembled monolayer. In this study, we used a fluorinated plasma chemical vapor deposition film as the antisticking layer. First, we formed a CHF3 plasma chemical vapor deposition (CVD) film on SiO2/Si and quartz molds and carried out thermal and UV nanoimprint using these molds. However, the film was removed from these molds. We found that the proposed method can solve this problem. We irradiated plasma using a gas mixture of CHF3 and O2 as the source gas onto SiO2/Si and quartz molds. As imprinting results, the patterns were successfully imprinted onto the resins without the removal of the plasma CVD film. In addition, we were able to carry out 100 times of repeated nanoimprinting using the plasma-CVD-film-coated SiO2/Si mold.

A fluorinated self-assembled monolayer (F-SAM) is mainly used as the antisticking layer. To prevent the F-SAM coated on the nanoimprint lithography (NIL) mold from deteriorating, we propose a new form of nanoimprinting using a release-agent-coated resin. The results from measuring the surface free energy and observations by scanning probe microscopy (SPM) confirmed that the surface free energy, frictional force, and adhesion force of the release-agent spray-coated polymethylmethacrylate (PMMA) were lower than those of PMMA. To prove the release-agent spray-coated PMMA had a releasing effect, we tried to undertake thermal nanoimprinting on it using a mold without F-SAM. The pattern was clearly imprinted on the resin without any signs of adhesion. (C) 2009 Elsevier B.V. All rights reserved.

In nanoimprint lithography (NIL), a mold is coated with an antisticking layer for preventing resin from adhering to it. A fluorinated self-assembled monolayer (F-SAM) is mainly used as the antisticking layer. The temperature of the mold in thermal NIL increases around the glass transition temperature of the resin. It is therefore important to assess the durability of the antisticking layer against heat. We evaluated the releasing effect of F-SAMs with and without annealing by using measurements obtained from the surface free energy and scanning probe microscopy (SPM). Furthermore, we examined the surface chemical composition and the surface morphology of F-SAMs with and without annealing using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM). From these results, we confirmed that the releasing effect of F-SAM deteriorated due to thermal decomposition when annealing over 500 degrees C. However, we found that F-SAMs annealed at 500 degrees C had a sufficiently large releasing effect in nanoimprinting. (C) 2008 Elsevier B.V. All rights reserved.

Room temperature nanoimprint lithography (RT-NIL) is a simpler process than thermal and UV NIL because it can be carried out without a resist thermal cycle and UV exposure. A fluorinated self-assembled monolayer (F-SAM) is mainly used as an antisticking layer. However, the F-SAM deteriorates due to repeated nanoimprinting. To prevent the F-SAM coating on the NIL mold from deteriorating, we propose a new imprinting technique using release-agent spray-coated hydrogen silsesquioxane (RASC-HSQ). We carried out RT-NIL onto it using a mold without F-SAM. The pattern was successfully imprinted on the resin without any signs of adhesion.

We report room-temperature nanoimprint (RT-NIL) process using sol-gel indium tin oxide (ITO) as a replicated material. The spin-coated ITO film has to be annealed at over 600 degrees C to obtain a low resistivity. The spin-coated ITO film can be delineated by RT-NIL, but the patterns disappeared after 200 degrees C annealing process. To overcome the above problem, we examined the O(2) plasma irradiation effect onto a spin-coated ITO film. As a result, we found that the ITO patterns imprinted by RT-NIL were kept at anneahng of 600 degrees C for 1 hour by O(2) plasma irradiation before annealing.

We have newly developed an imprinting technique using liquid-phase hydrogen silsesquioxane (HSQ) with Poly(dimethyl siloxane) (PDMS) mold. The patterns with various linewidth were demonstrated by imprinting using liquid-phase HSQ. And then, after imprinting, the residual HSQ layer that remained in the compressed area was less than 10 nm thick because the solvent in HSQ smoothly evaporated through the pores of PDMS mold.

The effect of annealing on implanted Ga of diamond-like carbon (DLC) films on Si substrates fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD) was investigated. Thermal desorption spectroscopy showed two Ga+ peaks at 470 and 630 °C. These temperatures agree with the results of energy-dispersive X-ray diffraction analysis of Ga concentration in the film. Cross-sectional transmission microscopy revealed changes in the structure of the DLC film at each temperature. At approximately 400 °C, the Ga in the film migrated to the surface and desorbed. Above 600 °C, the Si in the DLC layer near the damaged Si substrate interface recrystallized. These results can be applied to enable deliberate control of the mechanical properties of DLC films fabricated by FIB-CVD.

Diamondlike carbon (DLC) deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) has the interesting material characteristics because DLC deposited by FIB-CVD using the gallium (Ga) FIB contained Ga. The DLC wires were subjected to annealing, and it was found that their resistivity and the Ga content of DLC decreased. To understand the reason for the decrease in resistivity, changes in the fine structure and composition of DLC due to annealing were examined by transmission electron microscope electron energy loss spectroscopy and Rutherford backscattering spectroscopy/elastic recoil detection analysis, respectively. The results revealed that the graphite content of DLC increased due to hydrogen (H) elimination induced by annealing. Thus, it was concluded that the resistivity of the annealed DLC wires decreased due to the increase in the graphite content of DLC.

In nanoimprint lithography (NIL), molds are in direct contact with replication materials. Furthermore, the glass transition temperature is around 100–200 °C in thermal NIL. We examined the temperature dependence of a release effect for the antisticking layer of a self-assembled monolayer with a fluoropolymer by scanning probe microscopy (SPM). We measured the contact angle and frictional force of the antisticking layer with and without annealing. The contact angle decreases and the frictional force increases at annealing temperatures greater than 500 °C. We analyzed the chemical composition of the antisticking layer with and without annealing by X-ray photoelectron spectroscopy (XPS). From the obtained measurement results, the CF3 and CF2 peaks of the antisticking layer disappeared after annealing at temperatures greater than 500 °C. These results show that the antisticking layer annealed at temperatures less than 500 °C has a sufficient release effect.

The effects of annealing on the material characteristics of a diamond-like carbon (DLC) thin film fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD) were investigated. The elementary analysis, using Rutherford backscattering spectrometry and elastic recoil detection analysis, and measurement of hardness and Young's modulus, using a nanoindentation technique, were performed on the FIB-CVD DLC thin film by annealing for 1 h in the temperature range from room temperature to 1273 K. Elementary analysis indicated that the Ga content in the FIB-CVD DLC film used as an ion source began to decrease considerably at 523 K and the H content also began to decrease at 773 K. On the other hand, the hardness and Young's modulus of the FIB-CVD DLC film were found to decrease beyond 773 K. This decrease in hardness is ascribed to the variation in H content rather than in Ga content in the film.

Structural analysis was performed on the 55 kinds of diamond-like carbon (DLC) films. The ratio of sp(2) hybridized carbon in the film, sp(2)/(sp(2) + sp(3)) ratio, was determined by the carbon K-edge near-edge X-ray absorption fine structure (NEXAFS) spectroscopy using synchrotron radiation in the soft Xray region. In addition, hydrogen content in the DLC film was determined by elastic recoil detection analysis (ERDA) using an electrostatic accelerator. Furthermore, the density of the DLC film was measured by X-ray reflectivity method. Analyzed DLC films were divided broadly into four groups. Group 1 was characterized by high density, low sp(2)/(sp(2) + sp(3)) ratio and low H content. Group 2 was characterized by low density, high sp(2)/(sp(2) + sp(3)) ratio and low H content. Group 3 was characterized by medium density, and medium sp(2)/(sp(2) + sp(3)) ratio and relative high H content. Most samples in the present study were belonging to this group. Group 4 was characterized by low sp(2)/(sp(2) + sp(3)) ratio in spite of low density. H contents of samples in this group were relatively high. (c) 2008 Elsevier B.V. All rights reserved.

UV-nanoimprint lithography (NIL) has the potentiality to enable fabrication of nanostructures with high-throughput and low cost. The template is a key element in UV-NIL. Template patterns are directly transferred into the replicated materials. A repair technique is indispensable for UV-NIL template fabrication. However, only a few reports have appeared on the repair of UV-NIL templates. In this study, program protrusion and hollow defects on UV-NIL templates have been repaired by focused-ion-beam (FIB) etching and SiOx chemical vapor deposition (CVD) using tetraethoxysilane as a source gas. The imprinted line patterns were successfully replicated by UV-NIL using the repaired templates. Moreover, it has been confirmed that FIB etching and CVD can be applied to repair 30-nm defects on quartz templates.

Materials deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) have numerous interesting material characteristics. They contain gallium (Ga) because Ga is implanted by Ga+ FIB irradiation. Atomic ratios of the diamond-like carbon (DLC) deposited using phenanthrene (C14H10) as a gas source for FIB-CVD has the ratio of $\text{C} : \text{Ga} = 95 : 5$. And, It is also noted that the incorporated Ga in DLC is again segregated from DLC by annealing treatment. In this study, we found that Ga became agglomerated and was separated out from DLC by annealing treatment. Furthermore, Ga was passed out preferentially through the structural defect onto the DLC surface. Furthermore, the eduction position control of Ga sphere could be achieved using the via hole fabricated on the nanostructure by FIB-etching. This technique is utilizable for the formation of of junctions, such as a nano-bumps, to combine nanoelectromechanical devices.

The coordination of C atoms in diamond-like carbon (DLC) thin films formed by Ar gas cluster ion beam (GCIB) assisted deposition using fullerene as a carbon source was investigated using X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. From the curve fitting analysis of XPS spectra of the C 1s core level, the absolute sp 2 and sp3 contents in the DLC films formed by Ar GCIB-assisted deposition were evaluated for the first time. The absolute sp 3 content of DLC films formed by the GCIB-assisted deposition at an acceleration voltage of 5kV was the highest compared with that formed at 7 and 9kV. In addition, the absolute sp2 contents evaluated from XPS spectra were compared to the relative sp2 contents evaluated from NEXAFS spectra. ©2008 The Japan Society of Applied Physics.

Structure of the corrosion product films, which formed on hot-dip Zn-0.2%Al, Zn-5%Al and Zn-55%Al coatings in the early stages of corrosion reaction under the presence of NaCl particles, have been investigated by means of photoemission spectroscopy using synchrotron radiation and Al-Kα radiation. As a result, it is found that the surface compound of initial oxide film on Zn-Al coating changes from zinc oxide to aluminum oxide with increasing Al content, and that the structure depends on Al content. Additionally, the dominant compound of 1 nm or less in depth from the surface of corrosion products is seen to be different from that of 4 nm or less in depth. The corrosion resistance of Zn-Al coating is considered to be attributed to the depth profile of corrosion products on coating.

The control of wettability on a diamond-like carbon (DLC) thin film was carried out by exposing the film to synchrotron radiation (SR) ranging 50-1000 e V under perfluorohexane (C(6)F(14)) gas atmosphere. The contact angle of the DLC surface with a water droplet was found to increase from 73 degrees to 114 degrees by the SR irradiation under C(6)F(14) gas atmosphere. The chemical components variations of the DLC surface were studied using X-ray photoelectron spectroscopy and the modified DLC film with F was studied using near-edge X-ray absorption fine structure spectroscopy. By mounting the new sample holder for the parallel SR irradiation, we succeeded in preventing secondary reaction of deposited material and controlling the contact angle of the fluorocarbon modified DLC surface. (C) 2007 Elsevier B.V. All rights reserved.

Poly(tetrafluoroethylene) (PTFE) microstructures' processing characteristics are studied using X-ray photo-decomposition and desorption in the highest energy region (2 to over 12 keV). While the exposed surface states are observed to melt and boil from the remaining bubble structure on the irradiated surface, the basic photochemistry of PTFE is considered to be the same as that described in previous reports, and high-aspect-ratio structures are successfully formed. We developed new Ni-electroformed stencil masks and successfully fabricated the first and practical example of PTFE microfluidic part. The characteristics of the fabricated microfluidic part, a PTFE fluid filter for vertical fluid flow operation, which works as a passive valve, agreed with the calculated results. This Suggests that the accuracy of the patterning is adequate for the application of this technique to the fabrication of microfluidic parts and various other microparts.

It is necessary to manipulate and analyze single cells and organelles with high accuracy for a deeper understanding of their biological phenomena. For this purpose, bio nano-tools are very useful. We fabricated a bio nano-sensing probe by using focused-ion-beam chemical vapor deposition (FIB-CVD) and evaluated it using a cell of an Egeria densa leaf. We found that the probe functions as a measurement electrode. This indicates that the bio nano-sensing probe is useful for single organelle analyses.

Diamond-like carbon (DLC) deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) contains gallium (Ga) when a Ga ion beam is used. Therefore, DLC deposited by FIB-CVD (FIB-DLC) has specific material characteristics that differ from those of typical DLC. In this study, FIB-DLC's annealing-temperature dependence of field emission properties, work functions, and surface conditions were measured to understand its material characteristics. The results show that Ga incorporation is required in order to obtain a sufficient electric conductivity for the field emission. Furthermore, we found that the work function is increased by the graphitization of the FIB-DLC surface caused by the annealing treatment.

This is the first report on the precise elemental composition of a diamond-like carbon (DLC) thin film fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). The atomic fraction of the FIB-CVD DLC film has been determined to be $\text{C}:\text{Ga}:\text{H}=87.4:3.6:9.0$ at. % using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). The hydrogen content of the FIB-CVD DLC film was lower than that of DLC films formed using other CVD methods.

The annealing effect on the local structure of diamond-like carbon (DLC) formed by Ga+ focused-ion-beam chemical vapor deposition (FIB-CVD) was investigated by the incidence angle-dependent measurement of the C K-edge near edge X-ray absorption fine structure (NEXAFS) from 0 to 60°. The peak intensity corresponding to the resonance transition of $\text{1s} \rightarrow \sigma^{*}$ originating from carbon–gallium bonding markedly increased with incidence angle in the spectra of a FIB-CVD DLC film annealed at 400 °C. This angle dependency was attributable to the movement of residual Ga atoms from the bottom to the neighboring surface of the FIB-CVD DLC film.

The surface property of fluorinated diamond-like carbon (F-DLC) thin film, which is expected to be a new antisticking layer of nanoimprint mold, was evaluated with reference to the commercial diamond-like carbon (DLC) thin film formed by radio-frequency (RF) plasma chemical vapor deposition (CVD) and the fluorinated self-assembled monolayer (SAM). From the measurement of X-ray photoelectron spectrum (XPS), the surface of the F-DLC thin film was found to be overspread with hydrophobic CFx components. In addition, the durability of the F-DLC thin film was evaluated by the contact angle measurement of a water drop against repeating times of the thermal imprint process. After over 100 times of imprinting, the contact angles of the F-DLC thin film were almost kept constant with the initial value and a fine replicated pattern was obtained. From these results, the F-DLC thin film was found to be suitable as a novel antisticking layer of the thermal nanoimprint mold.

We have investigated the electronic and geometric structures of the Au-Si(100) surface as a function of annealing temperature by means of Si 2p and An 4f core-level photoemission spectroscopy and low energy electron diffraction (LEED). The 1 x 1, c(8 x 2) and 5 x 3.2 structures were obtained by annealing the Au-Si(100) surface at 250, 630 and 750 degrees C, respectively. From the intensity ratio of the An 4f to Si 2p spectra, it was found that the chemical composition was almost identical for the 1 x 1, c(8 x 2) and 5 x 3.2 structures. On the other hand, changes in the peak position and shape of the Si 2p and Au 4f spectra were observed when the 1 x 1/c(8 x 2) structure changed to the c(8 x 2)/5 x 3.2 structure. The spectral changes indicate that there are several components due to different Au-Si interactions. Based on the results of the Si 2p and Au 4f core-level photoemission analysis and LEED patterns, we discuss the electronic and geometric structures of the Au-Si(100) surface. (c) 2006 Elsevier B.V. All rights reserved.

We fabricated a silicon dioxide-based vacuum microcapsule using focused-ion-beam chemical-vapor-deposition (FIB-CVD) to realize three high-performance vacuum electronic micro-devices: a diode, a triode, and a sensor. We measured the electrical characteristics of diamond-like carbon (DLC) and silicon dioxide (SiO2) deposited using FIB-CVD, and found that they had characteristics that are useful in conductors and insulators, respectively, used in vacuum micro-device fabrication. Furthermore, to evaluate the inner vacuum of a microcapsule, a diode with a microcapsule was fabricated using FIB-CVD. By measuring the current–voltage ($I$–$V$) characteristics of the diode, it was demonstrated that the inner vacuum of the microcapsule was maintained. This result indicates that various high-performance three-dimensional vacuum micro-devices can be fabricated using FIB-CVD on any surface.

The contact angle on a diamond-like carbon (DLC) surface was controlled by synchrotron radiation (SR) under perfluorohexane (C6F14) gas atmosphere. It was found that the fluorocarbon group bonded to the DLC surface in the modified hydrophobic area from the measurement of X-ray photoelectron spectrum. The contact angle of a DLC surface was succeeded to increase from 73 degrees to 116 degrees by the SR irradiation with 400 mA center dot h at C6F14 gas pressure higher than 1.2 Pa.

Surface modification of a diamond-like carbon (DLC) thin film was performed using hyperthermal fluorine beams. After the irradiation of fluorine beam, the contact angle of a water drop against the DLC surface increased from 73 degrees to 87 degrees. The formation of C-F bonding was confirmed from the carbon K-edge near-edge X-ray absorption fine structure (NEXAFS) study on the DLC surface after irradiation of fluorine beam.

Electronic structures of oxide films on hot-dipped Zn-0.2%Al, Zn-5%Al, and Zn-55%Al coated steel sheets have been investigated by means of the synchrotron radiation photoemission spectroscopy and compared with those of Zn and Al pure metal sheets. The oxide films were prepared by 85 hour exposure in air saturated with water vapor at 323K. The oxide film on Zn-0.2%Al had the same photoemission spectrum as the pure Zn metal, while Zn-5%Al and Zn-55%Al were similar to the pure Al in the form of photoemission spectrum. It was found that the electronic structure of the oxide films and the depth profile of the ratio of zinc oxide to aluminum oxide are varied with the ratio of Zn to Al in the alloys. The corrosion resistance of Zn-Al alloys is discussed being related to the electronic structure of the oxide films.

The surface modification of poly(tetrafluoroethylene) (PTFE) sheet was carried out by exposing the sheet to synchrotron radiation (SR) ranging 50–1000 eV under O2, H2O and CH3OH gas atmospheres. The wettability of the PTFE surface was found to increase with SR dose under each gas atmosphere. The rate of increase in the wettability of the PTFE surface exposed to SR under the O2 gas atmosphere was higher than those of the PTFE surfaces exposed to SR under the other gas atmospheres. The decrease in the amount of –CF2 component and the presence of –C=O and –OH components were observed on a hydrophilic PTFE surface.

Diamondlike-carbon (DLC) cantilevers were fabricated with a commercially available focused-ion-beam chemical-vapor-deposition (FIB-CVD) system using a beam of 30 keV Ga(+) ions, and the mechanical characteristics of the cantilevers were measured. Vibration frequency of the cantilevers was passively measured using scanning electron microscopy. Resonant frequency of DLC cantilevers fabricated at 0.1 - 0.5 pA beam current was found to be constant. The equivalent spring constant of the cantilevers was identified by squeezing the tip of a Si(3)N(4) cantilever and a DLC cantilever together. Using the measured displacement, the spring constant of the DLC cantilever was calculated as (1.1 +/- 0.2) x 10(-2) N/m. Furthermore, Young's modulus and the density of the DLC cantilevers were measured to be 187 +/- 32 GPa and (3.8 +/- 0.7) x 10(3) kg/m(3), respectively. The DLC cantilevers were used as mass sensors in an ultrasensitive sensing application. A small amount of DLC was deposited on the tip of a DLC cantilever as a mass adhesion by FIB-CVD at 0.5 pA beam current. As a result, the authors were able to measure a small amount of mass shift in the femtogram range using a DLC cantilever. (c) 2006 American Vacuum Society.

The formation of microprotuberances on poly(tetrafluoroethylene) (PTFE) sheet by using synchrotron radiation (SR) was investigated. The PTFE surfaces irradiated by SR were observed with scanning electron microscope. The microprotuberances were formed on the PTFE surface by SR exposure at a substrate temperature over 150 degrees C. On the other hand, they were not observed at a substrate temperature of under 120 degrees C. The formation rate of microprotuberance remarkably increased above the glass transition temperature of PTFE. (c) 2006 Elsevier Ltd. All rights reserved.

Au-coated nanosprings were fabricated by a combination of focused-ion-beam chemical vapor deposition (FIB-CVD) and sputter coating. A Au thin layer was successfully coated onto nanosprings fabricated by FIB-CVD. To confirm the mechanical motion, the authors performed an optical microscopy observation in which the Au sputter-coated nanosprings were able to expand and contract mechanically, as flexibly as macroscale springs. The measured spring constants of the Au-coated nanosprings ranged from 0.27 to 16 N/m, depending on the coil-section diameter. In addition, through the quantitative measurement of the mechanical characteristic of the nanosprings, the authors estimated that Au-coated nanosprings had a sufficient mechanical strength, which is useful for application in nanoelectromechanical system with three dimensions. (c) 2006 American Vacuum Society.

We have investigated the Au-Si(111) interface as a function of the An coverage by the core-level photoemission spectroscopy. With increasing the An coverage, the spectral features in the Si 2p core-level changed remarkably and some fine structures in both Si 2p and Au 4f spectra were observed. Based on the curve fitting analysis, the Si 2p and Au 4f spectra at more than 20 angstrom An coverage were decomposed into three chemically different components, respectively. The assignments of their components were performed. In addition, we have compared these results for the Au-Si(I 1 1) interface with our previous study for the Au-Si(I 0 0) interface. It was found that the electronic structures for the Au-Si(I 1 1) interface is essentially identical to those of the Au-Si(l 0 0) interface except at the initial Au deposition. (c) 2006 Elsevier Ltd. All rights reserved.

Mechanically hard amorphous carbon nitride films were prepared by a combination of radio frequency (RF) bias voltage applied to a substrate and chemical vapor deposition using a decomposition reaction of BrCN with a microwave discharge flow of Ar. A pulsed operation of the negative RF bias voltage ($-V_{\text{RF } }$) was applied to avoid excess sputtering of the film. The $[\text{N}]/([\text{N}]+[\text{C}])$ ratios of the films were ${\approx}0.5$ irrespective of the application of $-V_{\text{RF } }$. The maximum hardness was $36\pm 10$ GPa for the film obtained under the conditions of $-V_{\text{RF } }=100$ V, a pulse period of 1000 s, and a pulse-on time of 800 s. According to the IR spectra, the intensity of the stretching vibration of the C–N bond was increased by the application of $-V_{\text{RF } }$. The Raman spectra showed increases in the relative intensity and width of the D-band. From these observations, the mechanism of film hardening when $-V_{\text{RF } }$ is applied was discussed.

The reaction mechanism for the direct photoetching of poly,(tetrafluoroethylene) (PTFE) using synchrotron radiation (SR) in the soft X-ray region, which is important for the microfabrication of PTFE nanoparts, was investigated by varying the photon flux irradiated to a PTFE sheet by changing the electron current of the storage ring. The etching depth of the PTFE sheet by SR exposure at 100mA(.)h was measured at room temperature, 120 and 200 degrees C. Etching depth increased with photon flux despite of setting the SR exposure on the same quantity at each substrate temperature. It was found that the etching of PTFE proceeds not only via the first-order reaction but also via the second-order reaction whether substrate temperature was higher than glass transition temperature.

Fluorinated diamond-like carbon (F-DLC) has recently been applied as an antisticking layer on nanoimprint molds for semipermanent use, replacing the self-assembled monolayer currently used. An SiO2/Si mold was successfully coated with an F-DLC thin layer by chemical vapor deposition (CVD). The measured water contact angle of the F-DLC surface was 103°, which is 30° higher than that of the DLC surface. This value indicates the adequacy of F-DLC as an antisticking layer. Moreover, an F-DLC film had a high hardness of 24 GPa, similar to that of a DLC film (26 GPa). AZ resist patterns of 150 nm linewidth and 350 nm pitch were successfully obtained by thermal nanoimprinting using an F-DLC-coated mold. Finally, after repeating the imprinting for more than 100 times, the initial water contact angle of 103° for the surface of the F-DLC-coated mold was maintained.

The control of wettability on a diamond-like carbon (DLC) surface was carried out by exposure to synchrotron radiation (SR) in the soft X-ray region under the perfluorohexane (C6F14) gas atmosphere. It was found that the contact angle of a water drop against the DLC surface increased with SR dose; in particular, it increased from 73 to 91° by the SR exposure of a 1 mA$\cdot$h dose. The formation of the hydrophobic DLC surface was attributable to the fluorine-functional groups that existed on the DLC surface after SR exposure under the C6F14 gas atmosphere.

We carried out the field-emission characterization of materials, such as diamond-like carbon (DLC), W, and Fe, deposited by focused-ion-beam chemical vapor deposition (FIB-CVD) to develop a field emitter to be used as a nano-tool for spot deposition. As a result, the threshold voltage of the field emission from the DLC was lower than those from the W and Fe. In addition, we measured the work functions of these materials using photoelectron spectroscopy and found that DLC has a low work function. Furthermore, a field emitter with a DLC tip as a cold cathode was fabricated on a glass capillary, because it was found to be able to emit electrons from the DLC using a low voltage. We also confirmed that electrons were emitted from a DLC tip fabricated by FIB-CVD.

Various shapes of three-dimensional nano-rotor have been fabricated using nano-sheet made by 30 kV Ga+ focused-ion-beam chemical-vapor-deposition (FIB-CVD) in the current range from 5 to 200 pA with phenanthrene vapor as a precursor. A nano-rotor moving has been observed using electrostatic attractive force and nitrogen gas blowing. Furthermore, the operational stability of four wings rotor with a longer axis has been confirmed by nitrogen gas blowing. (c) 2006 Elsevier B.V. All rights reserved.