岡 好浩

The impact of NiOx layers on the performance of inverted perovskite solar cells (PSCs) has been investigated using multiple analysis methods (thermal gravimetric, differential thermal analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and Soft X-ray photoelectron spectroscopy) of NiOx layers, which were made by spray pyrolysis deposition at different temperatures. The analyses of this study indicate that the efficiency of inverted PSC increases with the Scherrer crystallite size of NiOx. We also observed that the band state of the NiOx layer was changed by Na+ ions migrated from the glass substrate, which also had an impact on the efficiency. The results clearly showed that under high fabrication temperature, migration of matter from the substrate to the hole transport layer affects the electronic structure. Therefore, how these materials are engineered will be important to increase the efficiency of inverted PSCs.

Single-wall carbon nanotubes (SWCNTs) are promising materials for electronic applications, such as transparent electrodes and thin-film transistors. However, the dispersion of isolated SWCNTs into solvents remains an important issue for their practical applications. SWCNTs are commonly dispersed in solvents via ultrasonication. However, ultrasonication damages SWCNTs, forming defects and cutting them into short pieces, which significantly degrade their electrical and mechanical properties. Herein, we demonstrate a novel approach toward the large-scale dispersion of long and isolated SWCNTs by using hydrodynamic cavitation. Considering the results of atomic force microscopy and dynamic light-scattering measurements, the average length of the SWCNTs dispersed via the hydrodynamic cavitation method is larger than that of the SWCNTs dispersed by using an ultrasonic homogenizer.

This work studied the effects of tackifiers on the impact energy absorption properties of block copolymers (BCPs) comprising poly(styrene)-b-poly(isoprene)-b-poly(styrene) (SIS) and poly(methyl methacrylate)-b-poly(n-butyl acrylate)-b-poly(methyl methacrylate) (MAM). A rosin ester resin (RE) and an aliphatic petroleum resin (C5PR) were compared as the tackifiers. Analyses of Hansen solubility parameters and observations using electron microscopy indicated that both tackifiers were highly compatible with the poly(isoprene) component of the SIS, while the RE also showed good compatibility with the poly(n-butyl acrylate) phase of the MAM. The impact energy absorption characteristics of laminates made by applying layers of BCP/tackifier blends to cured epoxy substrates were evaluated using a pendulum impactor. The extent of energy absorption by these laminates was found to increase within specific tackifier concentration ranges. However, the C5PR showed poor compatibility with the MAM and had almost no effect on the energy absorption of the laminates. The energy absorption of the laminates could be described based on the calculated loss factor, eta, determined using the RUK equation including the viscoelastic parameters (both tan delta and storage modulus) for the BCP/tackifier blends, considering the time-temperature superposition principle, and for the laminate structures.

A silver nanocolloidal solution was prepared by a cavitation bubble plasma with a pair of silver rod electrodes in a sodium hydroxide water solution with the initial pH = 11.0. The cavitation bubble plasma was generated by the bipolar high voltage pulses of the repetition rate 200 kHz and the pulse width 0.8 μs in the sodium hydroxide water solution in which many cavitation bubbles produced by a high-speed rotor were feeding. The UV–Vis absorption spectra of the silver nanocolloidal solution exhibited a characteristic peak around 400 nm in wavelength. The silver nanocolloidal solution of 250 mL including silver nanoparticles of median diameter 1.3 nm and concentration 4 ppm was prepared at the processing time 1 min. The particle size in the solution increased with increasing the processing time and grew to 14.6 nm in median diameter at the processing time 20 min. The concentration of particles also increased with increasing the processing time. A TEM image of silver nanoparticles revealed that the particles were spherical crystalline.

The effects of pretreatment on adhesion, which is the most important challenge of diamond-like carbon (DLC) films, were investigated. DLC films were prepared by changing pretreatment conditions on austenitic stainless steel (SUS304) substrates by hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Although an oxide layer on a substrate surface was removed by Ar-plasma sputter cleaning, the substrate surface was immediately reoxidized when plasma was stopped for a moment between sputter cleaning and deposition. The DLC film on the oxide layer was poor adhesion strength less than approximately 50 MPa. Even if the oxide layer existed on the substrate surface, carbon ion implantation as an interface treatment in the PBIID process broke the oxide layer. As a result, the adhesion strength of DLC films was enhanced above the strength of epoxy resin (about 70 MPa). Furthermore, it was found that continuous generation of plasma after sputter cleaning was able to suppress reoxidation of the substrate surface. Consequently, the adhesion strength of DLC films prepared with no interface treatment was increased above 70 MPa, suggesting simplification of coating process and reduction in processing time for cost reduction.

<p>A cavitation bubble plasma, which is a kind of plasma in solution, is a low-temperature plasma generated in a large number of microbubbles of a solvent component generated by a cavitation phenomenon. In this paper, the cavitation bubble plasma technology is explained by introducing the originally developed apparatus, the discharge phenomenon, and the effect of cavitation bubbles. As application examples of cavitation bubble plasma, the results of water dispersion of carbon nanotubes, synthesis of silver nanoparticles, sterilization of Escherichia coli, and decomposition of methylene blue are introduced.</p>

© 2016 Elsevier B.V. Ether-based solid polymer electrolyte (SPE) is one of the most well-known lithium ion conductors. Unlike the other inorganic electrolytes, SPE exhibits advantages of flexibility and large-area production, enabling low cost production of large size batteries. However, because the ether group is oxidized at 4 V versus Li/Li+cathode, and due to its high irreversibility with the carbon anode, ether-based SPE was believed to be inapplicable to 4 V class lithium-ion batteries with carbon anode. Here we report a remarkably stable SPE in combination with a 4 V class cathode and carbon anode achieved by the proper design at the interface. The introduced boron-based lithium salt prohibits further oxidation of SPE at the cathode interface. The surface modification of graphite by the annealing of polyvinyl chloride mostly prohibits the continuous consumption of lithium at the graphite anode. Using above interface design, we achieved 60% capacity retention after 5400 cycles. The proposed battery provides a possible approach for realizing flammable electrolyte-free lithium-ion batteries, which achieve innovative safety improvements of large format battery systems for stationary use.

High-speed and homogeneous water-dispersion of carbon nano tubes (CNTs) with superior characteristics is a key technology for industrial applications. Liquid-phase plasma is one of good method to disperse CNTs in aqueous solution. However, the treatment speed of the liquid-phase plasma is not enough for industrial applications. In the present experiment, a novel high-speed dispersion device using cavitation bubble plasma (CBP) was developed. In this method the plasma was generated efficiently in bubbles in water. The cup-stacked CNTs were uniformly dispersed in ion-exchange water by the CBP treatment without dispersant. A liter of CNTs suspension with 9.2 wt% in concentration can be treated with the CBP processing of 135 min.

A discharge phenomenon was investigated to clarify basic property on cavitation bubble plasma in sodium chloride solution. The discharge plasma emission was observed by using charge coupled device camera with a high speed gated image intensifier unit. Generation and annihilation of plasma in the same cavitation bubbles were continuously repeated. The arch-like discharge path was formed on upper parts of the opposite electrodes because of cavitation bubbles produced on the upper parts of the electrodes besides the rotor part., which gradually extended to the direction that the solution flowed through. The maximum height of the arch-like discharge path was 4 mm, meanwhile the voltage of 160 pulses was applied between the electrodes. It was suggested that these phenomena were repeated in the different cavitation bubbles.

Metal nano-particle supported on titania (MNP/TiO2) photocatalysts are effective to generate hydrogen from an ethanol water mixture. Several chemical and physical methods have been reported for the fabrication of platinum nano-particles (PtNP/TiO2) and gold nano-particles (AuNP/TiO2) supported on titania. In general chemical techniques are more employed for the fabrication of these nanoparticles, but from the cost production point of view physical techniques based on plasma/laser are expected to be more advantageous. Furthermore, in the case of plasma generation in a liquid, for example, where the nanoparticles are fabricated directly into a liquid medium, there is the advantage that nanoparticle aggregation is avoided. Here we report on the development of a photocatalyst based on titania-supported platinum nanoparticles fabricated by cavitation bubble plasma technique and on its application for hydrogen generation.

High-voltage cathode material, LiMn Ni O , was successfully prepared by two-step process: LiMn Ni O particles were obtained by the solid state reaction of oxalate precursors at high temperature such as 900 °C and then the LiMn Ni O particles with Li-acetate di-hydrate and Ni-acetate tetra-hydrate were annealed at low temperature. Both spinel phases are ferromagnetic compounds: LiMn Ni O has higher Neel temperature (127 K) and larger magnetization (97 emu/g at 4.2 K) than LiMn Ni O does (103 K and 79 emu/g). The obtained LiMn Ni O particles had low specific surface area, which may reduce the side reaction with the organic electrolyte, and exhibited electrochemical capacity only at high voltage 4.7 V region. In addition, high reversible capacity as well as good cycle performance was attained. 1.5 0.5 4 1.6 0.4 4 1.6 0.4 4 1.5 0.5 4 1.6 0.4 4 1.5 0.5 4

LiCo Ni Mn O cathode electrodes were prepared using the doctor blade technique, where distilled water was used instead of ordinary NMP as the solvent. A serious problem is caused because the dispersion of hydrophobic carbon particles used as a conducting additive is difficult in water solvent. In this study, as a novel technique for the carbon particle dispersion, low-temperature liquid-phase plasma treatment was applied. The surface of carbon particle was converted from hydrophobic to hydrophilic via OH radical formation. The treatment enabled us to obtain stable colloidal dispersion of the carbon particles. The film electrode with smooth surface and no aggregates was easily attained. The electrode prepared using the water-based slurry has superior cycling performance and slightly-poorer rate capability compared to that of the electrodes prepared using the NMP-based slurry. 1/3 1/3 1/3 2

The structural change of Li[Ni Co Mn ]O cathode materials (x + y + z = 1) during the electrochemical delithiation/lithiation was studied with the in-situ X-ray diffraction. It was found that the cathode having the larger Ni fraction of Ni gave the larger unit cell volume change (ΔV) during the reaction. While the initial capacity increased with an increase in the Ni fraction, the capacity fading became much significant for the cathode with high Ni fraction. It was shown that the impedance originating from the cathode grew after the cycling and its degree increased with the Ni fraction. Additionally, micro-cracks were frequently observed for the cathode particles after the cycling evaluation, and the development feature of the micro-cracks was affected by the chemical composition of the cathode compounds. The capacity fading was discussed from the view-points of the lattice volume change, the impedance growth and the microstructure variation. x y z 2

Glow discharge-optical emission spectroscopy (GD-OES) was evaluated for hydrogen analysis in diamond-like carbon (DLC) films. DLC film samples were prepared using the plasma-based ion-implantation and deposition method (PBIID). Their hydrogen contents were determined using elastic recoil detection analysis (ERDA). The hydrogen intensity obtained by GD-OES increased gradually concomitantly with increasing hydrogen contents at the lower hydrogen content region. However, the intensity increased drastically at the higher hydrogen content region of more than about 30 at%. When the hydrogen contents increased, the correlation between GD-OES hydrogen intensity and ERDA hydrogen contents was deviated from the linear relation obtained for hydrogen-implanted silicon samples as reference materials. The sputtering rate of the DLC sample was found to vary at the high H content region. A linear relationship was obtained between the hydrogen contents and GD-OES intensities corrected with the sputtering rate of samples.

Diamond-like carbon film (DLC) is selected as a cathode-protective film because it has chemical inertness, mechanical hardness, and high electrical resistivity. For this study, a DLC protective film was deposited onto a cathode electrode rather than individual cathode particles. A hybrid process of plasma-based ion implantation and deposition was applied to a uniform deposition of the DLC protective film, even at low processing temperature on the cathode electrode having complex surface geometry and low melting point binder. The electrochemical performance of the DLC-coated LiNi Co Mn O cathode was studied using galvano-static charge- discharge cycling at high operating temperature, compared to those of the pristine LiNi Co Mn O cathode. The electrochemical stability of the DLC-coated electrode was discussed. The DLC film provides good protection against cathode/electrolyte interface degradation. 1/3 1/3 1/3 2 1/3 1/3 1/3 2

Li-deficient olivine compounds, Li Co Fe PO (x < 0.15), were prepared by calcination of the sol-gel derived precursors in ambient atmosphere. They were almost single phase at x < 0.10 but some impurity phases were found at x > 0.10. The lattice parameters changed continuously with an increase in the Fe substitution. Their variation in the range of x < 0.10 roughly obeyed Vergard's law. From the 57Fe Mössbauer spectrum at room temperature, it was shown that the introduced Fe took a trivalent highspin state in the olivine lattice. The temperature-dependent magnetic susceptibility exhibited that the Fe incorporation enhanced the antiferromagnetic ordering: the Neel temperature shifted higher. Furthermore, the electrochemical performances, such as cycling stability and rate capability, were improved significantly with an appropriate substitution (about 10%) with Fe3+. Consequently, the Fe3+ incorporated compounds with Li deficiency as the charge compensation are thought to be good candidates as high-voltage cathode material, which may enhance the energy density of Li ion battery. 1-x 1-x x 4

LiFePO₄ particles were prepared by the solid state reaction, and coated with conducting carbon layer through the hydrocarbon gas decomposition technique. The uniformity of the carbon layer was examined using the small angle X-ray diffraction with the core shell model. The half cell using these composite particles as cathode exhibited a peculiarity, that is, the capacity increment during the initial cycling process. In this study, the initial cycling process was studied with the AC impedance method. As a result, it was found that the interfacial impedance becomes small on the cycling sequence. It implies that the cathode/electrolyte interface is built on the initial cycling.

The composite cathodes were prepared using carbon wool as a current collector, where carbon-coated LiFePO₄ fine particles and acetylene black particles were applied as active material and conducting additive, respectively. The composite electrodes were thick film with sufficiently high active material loading. From the electrochemical redox test, they had almost the same energy density at low current density as the ordinary electrode on Al current collector. Simultaneously, the composite electrodes exhibited larger current density as compared with that of the ordinary electrode. According to the results, it is possible to fabricate the composite electrodes suitable to the battery application combining high-energy and high-power performance.

It has become more serious concern to quantify Low-k damage in Cu/Low-k interconnects. We investigated the relationship between the amount of OH group in Low-k material obtained from micro-beam IR method and the interconnect capacitance. And it was found that there is good correlation among them. Additionally, the micro-beam IR method sensitively detected modifications of amount of OH group for several kinds of treatment processes except for the NH plasma treatment prior to Cu diffusion barrier dielectric deposition. © 2012 IEEE. 3

The effect of ultraviolet (UV) curing on film properties of porogen based porous SiOC (P-SiOC) film was investigated. The P-SiOC films were prepared by plasma-enhanced chemical vapor deposition (PECVD) using alkoxysilane and porogen (hydrocarbon). UV curing time was changed from 0 s to 1000 s. The variation of the k value and elastic modulus on the P-SiOC film with UV curing can be classified into three phases. From the behavior of pore density and free volume rate evaluated by using positron annihilation spectroscopy (PAS), the multiphase model for structural modification of P-SiOC film by UV curing was proposed. In addition, the optimum UV curing time for obtaining a superior P-SiOC film with lower k value and higher mechanical strength was determined. © 2011 The Japan Society of Applied Physics.

In recent years, it has become more serious concern to achieve high reliability(EM, SM and TDDB) in Cu/Low-k interconnects. In this paper, we propose the simplest method to improve EM and SM reliability using the conventional SiCN deposition system without the complicated system and special source gases. And also, we propose a new hermeticity test procedure using TDS(Thermal Desorption Spectroscopy). © 2011 IEEE.

To reduce the effective dielectric constant (k ) value for 32nm node technology and beyond, the effects of a direct chemical mechanical polishing (CMP) process on porous low-k film without a protective cap layer were investigated. It was confirmed that a capless structure on porous low-k film is effective in reducing the resistance-capacitance (RC) products, but it causes degradation of wire-to-wire breakdown voltage characteristics. The most important point of a direct CMP process is to control the amount of damage to the polished surface. In this study, two types of low-k film were compared in combination with a variety of CMP process conditions. As results, we found that a direct CMP process has a positive effect on wire-to-wire current leakage and time-dependent dielectric breakdown (TDDB) reliability where a porous low-k film deposited by modified conditions is used. By optimizing the deposition and curing conditions, it is possible to control the distribution of different pore sizes in porous low-k film, which allows us to realize a highly reliable capless structure. © 2010 The Japan Society of Applied Physics. eff

We have improved ELK film so that it is suitable for the processes used in fabricating Cu interconnects without using a dielectric protection layer for CMP, the so called "direct CMP process". The depth profile of the pore size in the film was successfully controlled to prevent water absorption during the CMP process with a limited k-value increase in the film. The line-to-line dielectric breakdown voltage and the time dependent dielectric breakdown lifetime at the 45 nm spacing for the advanced ELK interconnects without the DPL were significantly improved. ©2010 IEEE.

In order to reduce the effective dielectric constant (keff) for the 32 nm technology node and beyond, Direct-CMP of a porous low-k film without a protective cap layer is required. However, the degradation of breakdown electric field (Ebd) has been one of critical issues. This study clarified that the Ebd degradation was caused by the pit defects on the surface of porous low-k film during Direct-CMP. In order to suppress the pit defects, we evaluated dependency of micro-pores density of CMP pads. As a result, we demonstrated that CMP pads with low-density micro-pores drastically reduced them and improved the Ebd degradation. In this paper, the mechanism for their reduction is also discussed. © 2009 IEEE.

In order to control the characteristics of porogen-based porous SiOC film (k < 2.5), we investigated its dependence on the wavelengths of ultraviolet (UV) light by using methods of FT-IR, TDS and nano-indentation. As a result, it was found that specific wavelengths of UV light strongly was effective to porous SiOC film production : porogen desorption, mechanical strength improvement, and reduction of the film damage. Vacuum ultraviolet (VUV) irradiation is necessary for porogen desorption. However, after porogen was removed from SiOC film, the energy of VUV irradiation was too high for porous SiOC film and this caused film damage. The energy of deep ultraviolet (DUV) irradiation was sufficient to improve mechanical strength. We propose that UV curing process should be a multi-step process consisting of VUV and DUV irradiation (Figure 1). The first step removes porogen using VUV irradiation. The second step forms robust porous SiOC film using DUV irradiation. A multi-step curing process was used to control the characteristics of porogen-based porous SiOC film. © 2009 IEEE.

The diamond-like carbon (DLC) film was prepared on various metal substrates with a plasma-based ion implantation and deposition using superimposed RF and negative high-voltage pulses. The adhesion strength of DLC film was enhanced above the epoxy resin strength by implantation of carbon ions or mixed ions of carbon and silicon to the substrate surface before DLC deposition. In order to clarify the mechanism for improvement in adhesive strength, the microstructure of an interface between DLC film and substrate was examined in detail by transmission electron microscopy (TEM) observations in combination with EDS analysis. As a result, the enhancement in adhesion strength of DLC film by C ion implantation resulted from the formation of amorphous-like phase in the ion-implanted region of substrate, the production of carbon-component graded interface, the destruction of the oxide layer on the top surface of substrate, and the reduction of residual stress in DLC film by ion implantation during the deposition. The production of stress-free DLC film allowed us to demonstrate a supra-thick DLC film of more than 400 μm in thickness. © 2008.

A 400 μm thick diamond-like carbon (DLC) film was prepared on an aluminum alloy (A5052) substrate by a hybrid process of plasma-based ion implantation and deposition using toluene as a precursor gas. The plasma-based ion implantation during deposition relaxed the residual stress in DLC film to almost 0, indicating the production of stress-free DLC. The carbon ion implantation from the methane and acetylene plasmas to the substrate surface, prior to deposition, resulted in an interface graded in carbon composition as well as the formation of amorphous-like structure at the carbon ion-implanted layer that should work as a buffer for stress-relaxation. As a result, a supra-thick DLC film more than 400 μm in thickness was prepared on the substrate. © 2008 Elsevier B.V. All rights reserved.

Diamond-like carbon (DLC) films were prepared on aluminum alloy (A5052) and tungsten-carbide (WC) substrates with plasma-based ion implantation and deposition (PBIID) using hydrocarbon gas. Adhesion strength of DLC film was increased by the formation of interfacial mixing layer by carbon ion implantation and the production of SiC nanolayer on the substrate prior to DLC deposition. As DLC films on the softer substrate were broken easily because of large deformation of substrate by local loads, the hard and supra-thick interlayer of plasma-sprayed tungsten-carbide (WC) with the thickness of 100-200 μm was produced to protect the softer substrate between the DLC film and the substrate. The scratch testing evaluation showed that the supra-thick WC interlayer improved remarkably the adhesion of DLC films on the aluminum alloy substrate and the thicker WC interlayer was more effective for improvement of adhesion. © 2007 Elsevier B.V. All rights reserved. x

This paper discusses the nano-interface between an aluminum alloy (A5052) substrate and diamond-like carbon (DLC) film prepared by a hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Adhesion strength of DLC films were enhanced by carbon ion implantation to the substrate. The nano-interface between DLC film and substrate was observed by high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) and analyzed by energy dispersive X-ray spectroscopy (EDS). It was found that an unclear crystal structure damaged by ion implantation was formed in the carbon ion-implanted layer. Besides, the amorphous mixing layer of oxide and DLC was produced on the substrate surface. The formation of the mixing layer, the layer of unclear crystal structure and the destruction of oxide led to the enhancement in adhesion strength of DLC film. © 2007 Elsevier B.V. All rights reserved.

High adhesive diamond-like carbon (DLC) film on SUS304 was obtained using carbon ion implantation between DLC film and substrate material by plasma-based ion implantation and deposition (PBIID). Implantation of mixed silicon and carbon ions to the substrate resulted in much higher adhesion strength than that of the epoxy resin. Effect of ion implantation on adhesion of DLC film was studied by cross sectional STEM observation and EDS element analysis. Enhancement in adhesive strength by ion implantation of mixed carbon and silicon was ascribed to the formation of the multilayer interface consisting of mixed carbon and silicon ion implanted layer and the amorphous layer of carbon and silicon. © 2006 Elsevier B.V. All rights reserved.

SiC(x) films were prepared by a hybrid process of plasma-based ion implantation and deposition using hexamethyldisiloxane (HMDSO) gas including silicon. The SiCx was composed of carbon, silicon, oxygen, and hydrogen. The Si/C in film is 0.34 without negative pulsed voltage, but Si/C is increased with increasing the negative pulsed voltage to 0.56. The hydrogen of 20 - 30 at.% was included in the SiC(x) Film. The residual stress of SiC(x) film was decreased with increasing ion implantation voltage from 0.2 GPa (compressive stress) to -0.2 GPa (tensile stress). The Vickers hardness of SiC(x) film was increased from 900 HV with -5 kV of ion implantation voltage to 1800 HV with -20 kV. A SiC(x) interlayer of 10 mu m in thickness was produced between the DLC film of 1 mu m in thickness and the aluminum alloy (A5052) substrate. Adhesion strength of DLC/SiC(x)/A5052 system was improved considerably.

Diamond-like carbon film (DLC) with an interlayer of plasma sprayed tungsten-carbide (WC) was prepared on an aluminum alloy substrate (A5052) by a hybrid process of plasma-based ion implantation and deposition using hydrocarbon gas. Typical thicknesses of DLC and WC films were 1 μm and 100 μm, respectively. The hardness and friction coefficient of DLC were typically 15 GPa and 0.15, respectively. The durability of DLC/WC/A5052 system was evaluated from the measurement of the friction coefficient by a ball-on-disk friction tester in which the loaded ball was drawn repeatedly across a sample and the load was increased with each traverse. For the DLC/A5052 system, which has no WC interlayer, the DLC film was broken quickly because of distortion of the substrate. For the DLC/WC/A5052 system, on the other hand, the DLC film was excellent in durability for long running. The wear rate of rubber rotor to the metal rotor was measured by a roller-pitching-type wear testing machine, showing large reduction in wear rate using DLC-coated metal rotor.

We examined the surface modifications of Zr50Cu30Ni10Al10 bulk glassy alloys, including oxidization, nitriding, and diamond-like carbon (DLC) coating to improve wear resistance. Wear abrasion in bulk glassy alloys begins with the formation of shear bands, as in cold-rolled structures. Ultimately, lamellar tearing occurs in the lamellar structure of the shear band in the wear region. Surface modification effectively reduces the wear abrasion corresponding to the easy formation of the shear band. Bulk glassy alloy coated with DLC has outstanding wear resistance due to its low surface-friction coefficient.

This paper discusses the effects of ion implantation on a diamond-like carbon (DLC) preparation using a hybrid process of plasma-based ion implantation and deposition (PBIID) using superimposed RF and negative high-voltage pulses. Adhesion strength of a DLC film on A-5052 and SUS304 was enhanced by carbon ion implantation to substrate materials.. Cross section of interface between the DLC film and substrate was observed by scanning transmission electron microscopy (STEM) and analyzed by energy dispersive X-ray spectroscopy (EDS). It was found that the amorphouslike mixing layer of graded carbon component and substrate materials was produced in the ion-implanted region of substrate and the oxide layer on the substrate surface was destroyed. Besides the reduction of residual stress in the DLC film, the formation of amorphouslike mixing layer and the destruction of oxide layer led to the enhancement in adhesion strength of the DLC film. Residual stress, spa fraction, hardness, density, and hydrogen content of the DLC films deposited from acetylene and toluene plasma have the variation with negative pulsed voltage for ion implantation.

Diamond-like carbon (DLC) film was prepared on Co-Cr alloy used for femoral head material of total hip arthroplasty by a hybrid process of plasma-based ion implantation and deposition using hydrocarbon gas. The tension test showed that the adhesive strength of DLC film was increased from 0.4 MPa without ion implantation to 2.8 MPa with carbon ion implantation. Furthermore, implantation of mixed carbon and silicon ions to the substrate led to considerable enhancement of adhesion strength up to 39 MPa that was comparable strength with the epoxy resin glue. DLC coating on Co-Cr alloy reduced the wear loss of ultra high molecular weight polyethylene (UHMWPE) used for a counterpart material in artificial joints.

The spectrum of optical emission from the plasma of hydrocarbon gases was measured with a photomultiplier and an optical multichannel analyzer in PBIID (plasma-based ion implantation and deposition) system. When negative pulsed voltage was applied to a sample, a strong optical emission was observed. It is important to know a contribution of negative pulsed voltage discharge on DLC (diamond-like carbon) synthesis. Spectra of CH (431 nm), Hα (656 nm), Hβ (486 nm) and Hγ (434 nm) were observed. Deposition rate of DLC film using acetylene gas was almost proportional to intensity of CH spectrum.

DLC (diamond-like carbon) films were prepared by the hybrid process of plasma-based ion implantation and deposition using acetylene plasma. The hydrogen content in DLC films decreased with the increase of negative pulsed voltage. The residual stress, density and hardness of DLC films had a peak at the negative pulsed voltage of 0 to -5 kV. At -5 to -20 kV, they had a correlation each other and considerably decreased with the increase of negative pulsed voltage.

High-adhesion diamond-like carbon (DLC) film was prepared by a hybrid process of plasma-based ion implantation and deposition using superimposed RF and high-voltage pulses. The adhesion strength of DLC film on a stainless steel (SUS304) was enhanced by the carbon ion implantation to the substrate. Furthermore, ion implantation of mixed carbon and silicon led to considerable enhancement of adhesion strength above the resin glue strength. The adhesion strength of DLC film on the aluminum alloy (A-5052) was improved above the resin glue strength only by the carbon ion implantation to the substrate.

A hybrid process of pulsed plasma-based ion implantation and deposition using two kinds of hydrocarbon plasma C2H2 and C 6H5CH3 was developed to produce diamond-like carbon (DLC) films, respectively. A residual stress of each film was measured as a function of negative pulsed voltage. The residual stress of the DLC film prepared by the C6H5CH3 plasma with -5 kV negative pulsed voltage reduced to 0.005 GPa. The microstructure of the DLC films prepared by the C2H2 and the C6H 5CH3 plasma was investigated. In the case of C 2H2 plasma deposition with -20 kV negative pulsed voltage, only an amorphous film was formed. In the process of deposition by C 6H5CH3 with -10 kV negative pulsed voltage, some fine particles were found in the amorphous film, which had a geometric shape, and the diameters of these particles were from 30 nm to 50 nm. It was found that they had the crystal structure of carbon (168H), which has the lattice constant of 0.32, 0.25, 0.2 and 1.9 nm. The formation of these carbon particles in the DLC film might be due to the generation of glow discharge. © 2005 Elsevier B.V. All rights reserved.

In this study, the microstructure of two kinds of diamond-like carbon films was studied. These films were produced during the deposition of two kinds of hydrocarbon gas plasma by a newly developed technique called plasma based ion implantation (PBII). Microstructural analysis was performed by means of high resolution transmission electron microscopy (HRTEM). An amorphous DLC film was obtained by using C2H2 plasma. The crystal structure of carbon ( (C)168H ) was generated inside the DLC film when C5H 6CH3 plasma was used. The effect of the precursor gases used in the present experiment on the microstructure of the DLC film was also studied. © 2005 Trans Tech Publications, Switzerland.

The thick diamond-like carbon (DLC) film of good-adhesion was prepared on a stainless steel (SUS304) substrate by a hybrid process of plasma-based ion implantation and deposition using hydrocarbon gases such as methane, acetylene, and toluene. In this process, a high repetition pulsed plasma was produced by RF pulse (13.56 MHz) with the duration of 50 μs and the repetition rate of 0.5-1 kHz. Besides, the plasma ions were implanted to the substrate by a negative pulsed voltage of -20 kV and the pulse duration of 5 μs. Ion implantation served to produce a graded interface of carbon component in the boundary region of DLC film and substrate, and also to reduce the residual stress to several MPa, enhancing the adhesive strength of DLC film. Furthermore, the adhesive strength of DLC film was increased above the epoxy resin strength (about 65 MPa) by implantation of mixed Si and C ions.