ICMCTF2008 Session BP: Symposium B Poster Session

Thursday, May 1, 2008 5:00 PM in Room Town & Country
Thursday Afternoon

Time Period ThP Sessions | Topic B Sessions | Time Periods | Topics | ICMCTF2008 Schedule

BP-2 Structure and Mechanical Properties of Al-Si-N Films With a Low and High Si Content
M. Sasek, J. Musil, P. Zeman (University of West Bohemia, Czech Republic)
The article reports on properties of Al-Si-N films with a low (≤10 at.%) and high (≥25 at.%) Si content reactively sputtered using a closed magnetic field dual magnetron system operated in ac pulse mode. The films were sputtered from composed target (a Si plate fixed by an Al ring with inner diameter 15 or 26 mm). Main attention was devoted to the investigation of a relationship between the structure of the films and their mechanical properties, thermal stability of hardness, and oxidation resistance. The structure and elemental composition of the Al-Si-N films were characterized by XRD and XRF or RBS. Mechanical properties were measured using microindentation and oxidation resistance was tested using TGA in flowing air. It was found that (1) while the films with a low (≤10 at.%) Si content are crystalline (c-(Al-Si-N)), those with a high (≥25 at.%) Si content are amorphous (a-(Al-Si-N)), (2) both groups of the films exhibit (i) high values of hardness H=21 and 25 GPa and of the oxidation resistance 950°C and 1150°C (Δm=0 mg/cm2), respectively, (3) the hardness of a-(Al-Si-N) does not vary after annealing for 4 hrs at 1100°C in air and (4) a high oxidation resistance of c-(Al-Si-N) film with a low (≤10 at.%) Si content is due to the formation of a densified Al2O3 surface layer which prevents the fast penetration of oxygen into bulk of the film.
BP-4 Deposition of TiN/CrN Multilayers with Nanometric Bi-Layer Periods by Cathodic Arc PVD
R. Martínez, J.A. García, M. Rico, R.J. Rodríguez (AIN, Centre of Advanced Surface Engineering, Spain); D. Caceres (Escuela Politecnica Superior, U. Carlos III, Spain)
The look for ultrahard and high wear resistant coatings has led to PVD coatings with multilayer structures in the nanometric range. In this line, PVD coatings alternating TiN and CrN layers and different bi-layer periods have been deposited on high speed steel and Silicon substrates, for investigating the mechanical and tribological properties and study their correlation with the bi-layer period. The coatings were deposited by cathodic arc in a semi-industrial PVD equipment and their total thickness was about 1.5 microns, and their mechanical and tribological properties were studied. The coatings were analysed by GD-OES, achieving quantitative in-depth profiles that could only reveal the multi-layered structure for the highest periods. A cold cathode FE-SEM equipment was also used for the observation of the structures. The images obtained revealed the nano-layered structures in all the cases, showing bi-layer periods in the nanometre range. The nanoindentation tests showed that coatings with lower bi-layer periods tended to present higher hardness values.
BP-5 Chromium Nitride Coatings Produced by Physical Vapor Deposition for Anti-Abrasive Flat Stainless Steel
A. Douard, M. Pierre, F. Tenailleau (ArcelorMittal Stainless, France); M.H. Berger (Ecole des Mines de Paris- ARMINES, France); P. Aubert, S. Labdi, N. Maitre (Laboratoire d'études des Milieux Nanométriques - Université d'Evry Val d'Essonne, France); F. Chassagne, J.M. Damasse (ArcelorMittal Stainless, France)

Physical Vapor Deposition is nowadays introduced in industrial production of metal strip coatings. When employed in the field of flat stainless steel, such new plasma technologies offer not only evolutions of present products, but create new products and so new markets. Besides, in comparison with conventional coating processes such as electroplating or conversion in chemical bath, on-line plasma deposition technologies represent alternative processes in respect of the new European environmental rules.

Stainless steel strip until 1.5 meters in width coated with chromium nitride nanolayers have been achieved by Cathodic Magnetron Sputtering at room temperature. Deposition parameters have been optimized in order to get chromium nitride nanolayers, in the first hand with uniformity and reproducibility, in the second hand with anti-abrasive properties and stainless steel aestheticism. Several stoechiometries of Cr:N have been attempted on austenitic AISI 304 and ferritic AISI 430 stainless steels, by monitoring N2 flow rate.

Morphology, microstructure and composition of Cr-N coatings on stainless steel were characterized at nanoscale by Transmission Electronic Microscopy, Atomic Force Microscopy, X-ray Diffraction, FEG-Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy. It was shown that Cr:N stoechiometry has a strong influence on the visual aspect of the coated stainless steel strips.

Adherence, hardness and friction behavior of the different chromium nitride nanolayers were deduced from nanoindentation measurements, nanoscratch and nanotribology tests. Results from mechanical macrotests such as pion disc, normalized Taber abrasimeter, and in-house abrasion test are presented. Mechanical properties in relation with stoechiometry, structure and thickness of the Cr-N thin films are discussed. High performance of flat stainless steel functionalized by Cr-N nanolayers against abrasion are discussed in relation with different coating features.
BP-6 Magnetron Sputtering of Hard Cr-Al-N-O Thin Films
M. Stüber, U. Albers, H. Leiste, C. Ziebert, S. Ulrich (Forschungszentrum Karlsruhe, IMF I, Germany)
The design and synthesis of advanced wear resistant thin films addressing the combination of metallic or covalent hard phases and oxide materials in a nanocomposite structure is an emerging new field of thin film research. In this paper, the phase formation, the evolution of the microstructure and the correlation between the constitution, microstructure and selected mechanical properties of thin film materials of the Cr-Al-N-O system is presented. A combinatorial materials science based approach was applied for magnetron sputtering from a segmented target (composed of one half of each bulk ceramic CrAlN and Al2O3) with a Leybold Z 550 machine. In each experiment, six coatings of different composition, constitution and microstucture were obtained simultaneously by placing six substrate samples in individual positions opposite to the target. Both non-reactive and reactive deposition processes (in nitrogen) were applied. The constitution, microstructure and mechanical properties (Vickers microhardness, hardness derived from nanoindentation experiments and Young`s modulus) of both as-deposited and thermally annealed coatings (annealing in vacuum up to 750°C) is discussed in dependence of their chemical composition. While the non-reactive deposition led to the growth of nanocrystalline thin films of moderate hardness but brittle character, the reactive deposition in nitrogen atmospheres led to the growth of nanocrystalline coatings with high hardness (up to 2500 HV0.05) and toughness. Annealing of these coatings in vacuum did not change the hardness values but led to a change of the crystalline structure of the coatings which could make them interesting candidates for technical applications at elevated temperatures.
BP-8 Luminescent Properties of Thin-Film ZnGa2O4 Phosphors by Facing Targets Sputtering
S.J. Kim, H.H. Kwak, S.J. Park, K.H. Kim, H.W. Choi (Kyungwon University, Korea)
Facing targets sputtering method was known stable working under broad magnetic field, range of gas pressure and stable electrical discharge under low Ar gas pressure and deposition at low temperature. In this study, the ZnGa2O4 phosphor thin film was grown using facing targets sputtering system at low substrates temperatures. Phosphor thin film was deposited on indium tin oxide (ITO) coated glass substrates and annealed by a rapid thermal processor (RTP). The characteristics of the deposited phosphor thin film were investigated by means of X-ray diffraction (XRD), Scanning Electron Microscope (SEM), atomic force microscopy (AFM), and Cathodoluminescence (CL). The X-ray diffracton patterns indicate that the ZnGa2O4 phosphor thin film shows a (3 1 1) main peak and a spinel phase. The emission spectra of ZnGa2O4 showed a broad self-activated blue emission band spanning over in the wide range of 300~600 nm with a peak wavelength of about 420 nm. The ZnGa2O4 phosphor thin film has better crystallization and luminescent properties due to increased annealing temperature.
BP-9 Ionized Magnetron Sputtered Alumina Thin Films
M. Sridharan, P. Eklund, M.B. Sillassen, J. Chevallier, J. Bøttiger (University of Aarhus, Denmark)
Crystalline alumina films have a wide range of applications due to their low refractive index, very high resistivity, low thermal conductivity, high hardness and wear resistance. In the present investigation, alumina films have been deposited onto chromia template layers by reactive ionized magnetron sputtering. An RF powered coil was located above the substrate to vary the ion flux hitting the substrate and the degree of ionization in the sputtered flux. The α-chromia templates were grown by reactive DC magnetron sputtering on pre-cleaned Si (001) substrates. A systematic investigation was carried out of the dependence of the nanostructure of the films and hence the mechanical properties on substrate bias voltage, deposition temperature and the RF power of the coil. The deposition rates for alumina films were 375 - 400 nm/h. Transmission electron microscopy and X-ray diffraction analysis revealed a phase mixed alumina. As analyzed by Rutherford backscattering spectrometry, all the alumina films had the chemical composition Al2O3. The mechanical properties of the films were studied by nanoindentation. For each film 100 indents were carried out with maximum loads ranging from 1.0 to 9.7 mN. The hardness values of the alumina films without and with chromia template layer grown at 300°C substrate temperature and 100 W RF power were 17 and 22 GPa, respectively, whereas the alumina film deposited over chromia template at 450°C substrate temperature and increased ion current density at the substrate, exhibited a hardness of 25 GPa.
BP-10 Thermal Stability and Oxidation Resistance of CrCu(N) Coatings Deposited by Twin-Crucible Electron-Beam Physical Vapour Deposition
K. Kanakis (University of Sheffield, United Kingdom); C. Tsotsos, C. Rebholz (University of Cyprus); A. Leyland, A. Matthews (University of Sheffield, United Kingdom)

CrCu(N) coatings with a nanocomposite structure have been identified as offering excellent wear resistance for applications involving abrasion, erosion and impact wear. Due to the low solid state miscibility of Cr and Cu (the former with or without an interstitial solid solution of N), predominantly metallic nanocomposites can be produced with high resilience and toughness, and a hardness close to that of ceramic coatings (>15 GPa). Also, by having low coating internal stress and an elastic modulus more closely matched to that of the substrate, the full benefit of these coatings can be obtained.

In this paper we discuss the thermal stability and high temperature oxidation resistance of CrCu(N) coatings of different composition, deposited by twin-crucible (one Cr-source and one Cu-source) Electron Beam Physical Vapour Deposition (EBPVD), in order to control independently each vapour source material. Plasma assisted EBPVD processes may be more attractive than sputtering for commercial applications, as potentially they offer lower running costs, higher maximum deposition rates, and improved flexibility for tailoring the through-thickness coating composition.

To characterise these coatings, techniques such as X-ray diffraction analysis and scanning electron microscopy have been employed. Hardness has been determined for coatings in both the as-deposited and the annealed condition. High temperature oxidisation resistance is investigated by means of thermo-gravimetric analysis, X-ray diffraction and scanning electron microscopy.
BP-11 Improving Corrosion Performance of CrTiAlN Coating by Sealing Detrimental Defects
Q. Yang (National Research Council Canada); F. Cai (Carleton University, Canada); L.R. Zhao (National Research Council Canada); X. Huang (Carleton University, Canada)
It is well known that coatings deposited by vapor deposition methods can have numerous microscopic defects, such as pinholes or pores, which are difficult to avoid during processing. The defective sites provide an easy access for corrosive medium to penetrate and reach underneath metal substrate, therefore initiating the localized corrosion at these sites. In this paper, several post-deposition sealing techniques, such as thermal oxidation and polymethyl methacrylate (PMMA) sealing, were applied to seal the pinholes or pores of a CrTiAlN coating deposited by reactive magnetron sputtering in an effort to alleviate the detrimental effects of the defects on the coating performance against corrosion. As-deposited and sealing-treated coating specimens were subjected to potentiodynamic polarization measurements in 3.5% NaCl aqueous solution. Also, the coating degradation as a function of immersion time was evaluated at open circuit potential using electrochemical impedance technique. The test results indicate that sealing the pinholes or pores can markedly improve the corrosion resistance of the coating, and no obvious degradation has been observed for the sealing-treated samples during the long-time exposure to the saline solution.
BP-12 Synthesis of Diamond Films by Pulsed Liquid Injection CVD Using Organic Compounds
J. Morales (Universidad Autonoma de Nuevo Leon, Mexico); L.M. Apatiga, V.M. Castaño (Universidad Nacional Autonoma de Mexico)
Diamond films were deposited on Si substrates by the Pulsed Liquid Injection Chemical Vapor Deposition (PLICVD) technique from different organic compounds including acetone, ethanol and methanol. The PLICVD reactor works by the flash evaporation principle of an organic liquid precursor. An effective pulsed liquid injection mechanism that consists of an injector, normally used for fuel injection in internal combustion engines, injects small micro-doses of the precursor to the evaporation zone at 280 °C to be instantly evaporated. Te resulting vapor mixture is transported by a carrier gas to the high-temperature reaction chamber, where the diamond nucleate and grow on the substrate surface a temperatures from 650 to 850 °C. The deposited films were characterized by Raman spectroscopy, SEM and AFM. Our early results show a ball-shaped morphology with a grain size that varies from 100 to 400 nm as well as the characteristic Raman band at 1332 cm-1 of diamond. The effect of the experimental parameters and operation principle on the diamond film quality are analyzed and discussed in terms of their crystallinity, composition, structure and morphology.
BP-14 Tribological Behaviors of Ti-Al-O-N Thin Films by Cathodic Arc Evaporated Process
W.-Y. Ho, S.-H. Shieh, C.-L. Chang, D.-Y. Wang (Mingdao University, Taiwan)
The development of wear resistant coatings for cutting applications is rapidly progressing. The structure, mechanical properties, and wear performance of arc evaporated Ti-Al-O-N coatings have been investigated in this study. The various Ti-Al-O-N coatings were synthesized by using an AlTi target and varied O2/(O2+N2) gas flow between 0 to 16%. The coating structure was designed with tripled layers in which were composed of TiN as interlayer, TiN/TiAlN multi-layer and TiAlON top layer. The structural of the various coatings were analyzed using SEM, AFM, XRD, and XPS. The mechanical properties were investigated using nanoindentation and the wear behaviors were analysed by pin-on-disk tribometer. The coatings performances in wear tests were evaluated against WC ball in dry and wet conditions, respectively. It is shown that the addition of oxygen into the arc deposition process leads to the formation of a dual phase structure including oxides and nitrides in the TiAlON. The addition of oxygen increases the ductility of the coatings, which improves the performances in wear tests. At high levels of oxygen, however, the performance is dramatically reduced as a result of increased crater wear.
BP-15 Grain Boundary Scattering for Temperature Coefficient of Resistance (TCR) Behavior of Ta-Si-N Thin Films
C.K. Chung, A. Nautiyal, T.S. Chen (National Cheng Kung University, Taiwan)
In this study, we have investigated the electrical properties of TaxSiyNz thin film deposited by reactive co-sputtering at different nitrogen flow ratios. The electrical resistivity and temperature coefficient of resistance [ ] were measured by an I-V measurement system including the four-point probe from room temperature to 100°C. The results indicated that the electrical resistivity decreased with increasing temperature in each film prepared at different N2 flow ratios. The phase formation of Ta-Si-N film at different N2 flow ratios (5%~20%) as well as change in microstructure from amorphous to polycrystalline was studied by grazing incident X-ray diffractometer. In view of the fact that grain size increases with increasing N2 flow ratio, it would be expected that increasing resistivity and negative TCR with increasing polycrystalline nature may be due to scattering of electrons by the grain boundaries. It is probable that polycrystalline materials have higher electrical resistivity due to high ratio of grain boundary area. The electrical properties of these films are also discussed by the grain-boundary scattering model. Since Ta-Si-N film can be patterned by IC compatible etching process, it is useful for future application to sensor arrays.
BP-16 Preparation of Titanium Oxynitride Thin Films by Reactive Sputtering Using Air/Ar Mixtures
M.-H. Chan, F.-H. Lu (National Chung Hsing University, Taiwan)
Titamium oxynitride (TiNxOy) thin films have many applications, such as solar cell and biomedical materials. In the literature TiNxOy films have often been prepared by controlling N2/O2/Ar mixing ratios. In this study, TiNxOy films were prepared by DC magnetron sputtering using air/Ar mixtures. This process, though being much simpler, could achieve similar quality of the films reported from the literature. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FE-SEM) were used to characterize obtained thin films. When the air/Ar ratio increased from 0.15 to 0.4, the color of the films changed from silver-like to golden. TiNxOy films with oxygen content being greater than 25% were determined by XPS. XRD patterns show that the preferred orientation of films with rock-salt structure varied from (111) to (200). As the air/Ar ratio increased up to 0.5, the films exhibiting amorphous structure comprised of mostly TiO2 phase and the oxygen content would reach about 50%. The thickness of the films decreased with increasing air/Ar ratio, examined by FE-SEM. The mechanical properties of the films were discussed as well.
BP-17 Effect of Magnetic Field Strength on The Mechanical Properties of CrN Film Deposited by Unbalanced Magnetron Sputtering
Y.-S. Yang, W. Huang (National Kaohsiung First University of Science and Technology, Taiwan); P.-H. Wang (I-Shou University, Taiwan)
This paper presents the effect of varied magnetic field on CrN films deposited on die steel with PVD sputtering. The strength of magnetic filed controlled by adjusting the gap between magnets set and target surface (GMT) of the unbalanced magnetic field sputtering system. A L18 Taguchi orthogonal experiment was progressed for discussing the effect of varied magnetic field and other parameters, such as target current, argon and nitrogen flow rate, DC pulse frequency, and working distance. Each parameter exhibits tree layers of value. The magnetic filed was measured by a gaussmeter and the schematic diagram of the magnetron system was plotted according from measured results. The mechanical properties were measured, such as hardness, adhesion, thickness, and friction coefficient. With an analysis of variance (ANOVA) table of orthogonal experiment, film hardness, thickness and friction coefficient were analyzed into three parts for the percentage contribution. Among results, the GMT exhibited the greatest percentage contribution (34.3%) to friction coefficient in comparison with other two properties, which showed that GMT is extremely sensitive to friction coefficient. The results showed that a middle layer of GMT (38 mm) exhibited smallest friction coefficient. The relation between magnetic field and microstructure of deposited CrN films was also observed in this paper.
BP-18 Development of Artificial Neural Networks for the Friction Coefficient on Cr1-xAlxC Films Deposited by Unbalance Magnetron Sputtering
Y.-S. Yang, T.-C. Fu, W. Huang (National Kaohsiung First University of Science and Technology, Taiwan); G.-W. Li (Everest Textile Co., Ltd., Taiwan)
This paper presents a prediction method applying a Generalized Regression Neural Network (GRNN) for the friction coefficient of deposited Cr1-xAlxC films on high-speed steel substrates by DC reactive magnetron sputtering. The Cr1-xAlxC films exhibited a fine columnar grain microstructure with some special characteristics, such as high hardness, a low friction coefficient, and a large contact angle. Although so many advantages are shown above, it is difficult to find an easy way for getting the properties of the films because the experiments must be progressed. In this study, a model was applied for predicting the friction coefficient of Cr1-xAlxC films on high-speed steel substrates instead of complex practical experiments. The proposed model consists of the Generalized Regression Neural Network with 25 training sets and 2 testing sets. The results of the testing set get a good accuracy of friction coefficient since about ±0.97% average errors and show the feasibility of the prediction model.
BP-19 Synthesis and Characterization of Nano-Composite Ti-Si-N Hard Coating by Filtered Cathodic Arc Plasma Evaporation
C.-L. Chang (Mingdao University, Taiwan); J.-H. Chen, P.-C. Tsai (National Formosa University, Taiwan); W.-Y. Ho, D.-Y. Wang (Mingdao University, Taiwan)
Nano-composite Ti-Si-N films have been deposited on M2 tool steel substrates using TiSi-target arc sources by a Filtered cathodic arc plasma evaporation system. The influences of bias voltages on the microstructure, mechanical and corrosion properties of the films were investigated. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction techniques were employed to analysis the microstructure, grain size and residual stress. Nano-indentation and tribometer tester were used to measure the mechanical and tribological properties of nano-composite Ti-Si-N thin films. The corrosion behavior of coatings was investigated using polarization and immersion tests. Both bias voltage and filter duct has important effects on the deposition growth and microstructure of coatings. All our coatings presented hardness higher than conventional TiN coatings. It has been found that the microstructure, mechanical, and corrosion properties of the films were correlated to Si concentration in the coatings. The influences of increasing bias voltage on the microstructure, mechanical and corrosion properties of the films lead to increasing Si concentration and decreasing grain size in the films. The corrosion resistance of coatings tested in 1 N H2SO4 solution was confirmed that (Ti,Si)N coatings was better than TiN coating since the effect of Si add in TiN and more dense nano-crystalline structure formed. The results turned out that better mechanical properties and corrosion resistance of (Ti,Si)N coatings can be obtained in this study.
BP-20 Electric-Pulse-Induced Resistance Switching in CaCu3Ti4O12 Films Grown by RF-Sputter
L.-C. Chang (Huafan University, Taiwan); F.B. Wu (National United University, Taiwan)
The electric-pulse-induced resistance-change (EPIR) switching effect in oxides is attractive for its potential use in non-volatile resistance random access memories (RRAM). The resistive switching behaviors of RF-sputtered CaCu3Ti4O12 (CCTO) memory films were investigated in this work. Both the switching bias voltage and the resistance ratio of RESET to SET were found to be strongly annealing temperature dependent. This switching mechanism from high current state to low current state is thought to be due to the fact that the defects present in the CCTO film randomly trap electrons. Meanwhile, the electrical characteristics can be exactly examined by Frenkel-Poole emission. By means of mathematical fitting, the resistance bistability seems to be related to the alternating of dielectric constant. The CCTO films with high uniformity and good stability are expected to be used in nonvolatile memory.
BP-21 Annealing Study of Mo-Ru Hard Coatings on Tungsten Carbide
Y.I. Chen (National Taiwan Ocean University, Taiwan); L.-C. Chang (Mingchi University of Technology, Taiwan); J.-W. Lee (Tung Nan University, Taiwan); Y.-C. Kuo (National Taiwan University of Science of Technology, Taiwan); C.-J. Wang (National Taiwan University of Science and Technology, Taiwan)
High melting point metal alloys coating has been widely used as a protective coating on the top surface of glass molding die to prolong the lifetime time of die material. The oxidation resistance of the coating under the cyclic thermal history in mass production is a critical topic. In this study, Mo-Ru coating was used as the top coating and deposited by sputtering at 600°C, which revealed a columnar structure with a major axis perpendicular to the substrate. Mo-Ru coatings annealed at 600°C in vacuum state and molding environment are investigated, respectively. Both the diffraction peak shift and grain growth of the Mo-Ru coating under vacuum annealing are neglected. In the molding environment, the oxygen is absorbed into the Mo-Ru deposits, which affects the phase stability and mechanical properties.
BP-23 Deposition of High-Quality Hydrogenated Amorphous Silicon Films by MWECR-CVD System With Hotwire Assistance
G. Chen, J. Deng (Bejing University of Technology, China)

As a new functional material, a-Si:H (hydrogenated amorphous silicon) films have been widely applied[1] to semiconductor devices, such as photosensitive devices, solar cells and thin film transistors (TFT) etc. However, light-induced metastable defects or in other words Staebler-Wronski effect limits its efficiency of the photonic devices as an inexpensive semiconductor material. So it is important to study the stability of a-Si:H. Microwave electron cyclotron resonance-chemical vapor deposition (MWECR-CVD) due to its attractive features has been used for the deposition of the a-Si:H films. However, there still exist some problems in the films prepared by the conventional MWECR-CVD system, such as poor stability, low photosensitivity, etc. So, based on the previous work,[2][3] we develop a new system assisted by hot wire to obtain high-quality a-Si:H films. The experimental results indicate that in the microstructure of the a-Si:H films, the concentration of dihydride is decreased and a trace of microcrystalline occurs, which is useful to improve their stability,and that in the optoelectronic properties of the a-Si:H films, the deposition rate reaches above 2.0nm/s and the photosensitivity increases up to 4.71×105.

[1]Kitagawa M, Setsune K, Manabe Y and Hirao T J. Appl. Phys. 61(1987)2084

[2]Yin S Y and Chen G H Phys. 4 (2004) 272 (in Chinese)

[3]Hu Y H, Yin S Y, Chen G H et al. Acta Phys. Sin. 53(2004) 2263 (in Chinese).
BP-25 Corrosion Behaviour of the SAE-4140 Steel Implanted With Nitrogen Ions in Hydrogen Environments
S. Liscano (Unexpo Vicerectorado Puerto Ordaz, Venezuela); E. Niño (Universidad Industrial de Santander, Colombia); L. Gil (Unexpo Vicerectorado Puerto Ordaz, Venezuela); V. Jabon (Universidad Industrial de Santander, Colombia)
The aim of this work was to investigate the improvement in hydrogen embrittlement resistance by the use of nitrogen ion implantation on SAE-4140 steel. The three-dimensional ion implantation (3DII) is a technique for advance surface treatment and, in this case, the samples were implanted in a Joint Universal Plasma and Ion Technologies Experimental Reactor, by mean a high voltage pulsed discharge at low pressures. The samples were treated by nitrogen ion implantation with energies between 10 to 20 keV, with an implanted doping between 5x1016 to 5x1017 iones/cm2.The hydrogen embrittlement resistance of these implanted systems was assessed applying stress corrosion cracking (SCC) test, in a solution of hydrated sodium thiosulfate (Na2S2O3.5H2O), coupled with scanning electron microscopy (SEM) technique to analyze the samples surfaces before and after testing. The experimental results indicate that after 300 h of exposure in SCC test, the ion implanted samples with nitrogen have not evidenced cracking neither elongation. On other hand, the untreated samples of SAE 4140 steel fractured in the first 12 h, which support the effectiveness of ion implantation surface treatment.
BP-26 Synthesis and Mechanical Properties of Cr-Mo-Si-C-N Coatings by a Hybrid Coating System
J.H. Yun, K.H. Kim (Pusan National University, Korea)
In this work, the Cr-Mo-Si-C-N coatings were synthesized on steel and Si wafer by hybrid coating system, where arc ion plating (AIP) technique using Cr target was combined with a magnetron sputtering technique using Mo and Si targets in Ar/N2 gaseous mixture. The effect of changing Si content on the microstructure and mechanical properties of Cr-Mo-C-N coatings were systematically investigated. The coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscope (HRTEM) and microhardness indentation, etc. The results showed that the Cr-Mo-Si-C-N coatings were characterized by a nanocomposite comprising nano-size Cr-Mo-C-N crystallites embedded in amorphous Si3N4 matrix. The high hardness of Cr-Mo-Si-C-N coatings was related to this kind of microstructure. The corresponding mechanism was explored in this work.
BP-27 Influence of Substrate Bias Voltage on Microstructure and Mechanical Properties of Cr-Mo-Si-N Coatings
S.G. Hong, K.H. Kim (Pusan National University, Korea)
Quaternary Cr-Mo-Si-N coatings have been deposited on steel substrate and Si wafers by a hybrid coating system of arc ion plating (AIP) and DC magnetron sputtering techniques at various substrate bias voltage. Influence of substrate bias voltage ranging from zero to -400 V on microstructures and mechanical properties including microhardness, indentation elastic modulus of Cr-Mo-N and Cr-Mo-Si-N coatings were systematically investigated in this work. The microstructure changes of the coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM) in this work. The result showed that substrate bias voltage had an important effect on properties of coating. As the substrate bias voltage of Cr-Mo-N and Cr-Mo-Si-N coatings increased from zero up to -50 V, the film thickness decreased and the residual stress increased. At higher substrate bias voltage than -50 V, however, the film thickness increased and the residual stress decreased. The microhardness was changed by varing substrate bias voltage from zero to -400 V.
BP-28 Effect of Thermal Treatment on Resistive Switching Characteristics in Pt/Ti/Al2O3/Pt Devices
S.-Y. Wang, C.-Y. Lin, M.-H. Lin, C.-C. Lin, T.-Y. Tseng (National Chiao Tung University, Taiwan)
Resistive switching characteristics of Pt/Ti/Al2O3/Pt memory devices annealed at 400°C, 500°C and 600°C for 1 h under atmosphere condition were investigated in the study. The Al2O3 thin films annealed at up to 600 °C for 1 h maintain amorphous phase based on the X-ray diffraction (XRD) analyses. As increasing annealing temperature, the forming voltage of the memory device decreases in contrast to the rising trend of turn-on voltage (switching from high to low resistance state). However, turn-off voltage (switching from low to high resistance state) is almost independent of annealing temperature. These phenomena might be attributed to the interdiffusion between Ti and Al2O3, according to the analyzed results of secondary ion mass spectroscopy (SIMS) and high resolution transmission electron microscope (HRTEM).
BP-29 Magnetron-Assisted Inner Coating Process
D. Hagedorn, F. Löffler, R. Meeß (Physikalisch-Technische Bundesanstalt, Germany)
Various applications requires coatings on inner surfaces of components. Examples are the inner cylinders of engines and inner surfaces of bearings. For special sensors, e.g. acceleration measuring sensors, or for magnetic bearings, a special surface function, e. g. electric conductivity, has to be realized with an inner coating. Most of the applications need a coating with a high homogeneity and an even thickness distribution of the inner surfaces without significant heat-up during the coating process. A magnetron-assisted sputtering process should fulfill these requirements. The present paper describes a sputter-cathode system using cylindrical permanent magnets for the position inside the cylindrical cathode (post magnetron PM) or on the ends of the tubes, to be coated (ring magnetrons RM). The study uses cathodes with a diameter of 2 and 4 mm made of copper. Cylindrical substrates are made of aluminium alloy and have an inner diameter of 10 mm, only. Theoretical considerations, evaluations of the magnetic fields, set-up and realization of the experiment as well as coating characterization are content of the paper. Due to the high relevance for the function of precision sensors the study will present the structure and the thickness distribution of the inner cylindrical coatings.
BP-30 Ferroelelctric Properties of (Pb1.1La0.08)(Zr0.65Ti0.35)O3 (PLZT) on TiO2/Pt/Ti/SiO2/Si Substrate According to Various Post-Annealing Temperature of TiO2 Buffer Layer
J-.E. Yoon, Y.-G. Son (Pusan National University, Korea)
The (Pb1.1La0.08)(Zr0.65Ti0.35)O3 (PLZT) films were prepared on TiO2/Pt/Ti/SiO2/Si substrates by R.F magnetron sputtering method in order to improve the ferroelectric characteristics. The properties of the PLZT films were improved by TiO2 buffer layer, which will affect the nucleation and growth of the film according to post annealing. We observed that the phase of TiO2 thin films changed from anatase phase to rutile phase according to increasing post annealing temperature. Ferroelectric properties and crystallinities of PLZT thin films with various post annealing temperature of TiO2 buffer layer were observed, using X-Ray Diffraction (XRD), Precision LC (Radient Technologies. Inc.) and AFM(atomic force microscope.
BP-31 Evaluation on Composition, Homogeneity, and Hardness of High Phosphorus Content Electrodeposited Nickel-Phosphorus Binary Coatings
Y.M. Su, Z.Y. Chi, J.J. Wu, T.H. Wu, F.B. Wu (National United University, Taiwan)
Binary nickel-phosphorus coatings were fabricated by direct current electrodeposition with Brenner-type plating bath on pure Cu substrates. The deposition parameters, including anode-to-cathode area ratio, current density, working distance and substrate edge geometry were controlled to optimize the homogeneity and related properties of the Ni-P coatings. The electroplated Ni-P coating in the as-deposited state exhibited an amorphous/nanocrystalline Ni matrix with supersaturated P. The surface morphology was independent of anode-to-cathode area ratio during Ni-P deposition process. The elemental distribution of Ni and P of Ni-P coatings was investigated by scanning electron microscopy and electron probe microanalysis, respectively. A well-distributed Ni and P concentrations and uniform coating thickness were observed under the optimized current density of 0.75 mA/mm2 with a working distance of 50 mm. The significant variation in composition distribution of the Ni-P deposits in edge areas of various substrate edge types under different current density were evaluated and analyzed. In addition, the effect of composition distribution and heat treatment on hardness of Ni-P with high P content was intensively discussed.
BP-32 The Effect Post Annealing and Various Substrate of Ba0.5√sub 0.5TiO3 (BST) Thin Films Deposited by R.F. Magnetron Sputtering
I.-S. Lee, J-.E. Yoon, W.-H. Cha, C.-S. Lee, Y.-G. Son (Pusan National University, Korea)
The Ba0.5√0.5TiO3 (BST) thin films have been deposited by R.F. magnetron sputtering on Pt/Ti/SiO2/Si and ITO-coated glass substrates. Crystallinity of Ba0.5√0.5TiO3 thin films were observed using X-Ray Diffraction (XRD) and Scanning Electron Micoscope(SEM). It was found that the crystallinity of the Ba0.5√0.5TiO3 thin film was dependent upon various substrate and post annealing temperature. Also the role of different bottom electrode on the electrical properties of Ba0.5√0.5TiO3 films has been also investigated. Ferroelectric properties of Ba0.5Sr0.5TiO3 thin films with various post annealing temperature on Pt/Ti/SiO2/Si and ITO-coated glass substrates were observed, using Precision LC (Radient Technologies. Inc.) and GDS (glow discharge spectrometer.
BP-33 From Laboratory to Industrial Scale - Comparison of Simulation and Plasma Diagnostic Investigation of the Reactive Sputter Deposition of Alumina on Different Coating Units
K. Bobzin, N. Bagcivan, P. Immich, D. Parkot (RWTH Aachen University, Germany)
During the reactive sputter deposition of ceramic coatings physical phenomena related to the target poisoning are observed. These effects are strongly associated with the dimensions and equipment of the recipients, they complicate the comparison and the upscaling of deposition processes from laboratory to industrial coating units. The presented work deals with the experimental and numerical investigation of the reactive sputtering of alumina on different coating units. The aim was to investigate different influencing variables, adjustable as well as constructional, to allow a more efficient upscaling of processes developed on laboratory units. Numerical investigations based on the commonly used Berg model for reactive sputtering adapted to the considered cases were performed for the different setups. Additionally experimental measurements using optical emission spectroscopy and Langmuir probe diagnostics were done at the investigated coaters and compared to the numerical results.
BP-34 Theoretical and Experimental Study of the B-Cl-H Subsystem for the CVD of Borides
G. Reinisch (University Bordeaux 1, France); J.M. Leyssale (CNRS, France); N. Bertrand, G.L. Vignoles (University Bordeaux 1, France); G. Chollon, F. Langlais (CNRS, France); R. Méreau (University Bordeaux 1, France)

Boron and borides are well-known compounds used in hard coatings, because of excellent high-temperature properties. Chemical Vapor Deposition is an important route for their synthesis. One of the main sources is boron trichloride. For example, boron carbide may be synthesized by CVD from BCl3/H2/CH4 mixtures. However a precise control of the deposit quality (microstructure, stoichiometry) is difficult to achieve, due to an important sensitivity to processing conditions, like temperature, pressure, flow rate and gas mixture composition. In order to minimize development costs, CVD modeling is an attractive option.

In this context, a first step is to set up a homogeneous chemical mechanism, featuring thermochemical and kinetic data for a large set of species and reactions. Since the gas-phase chemistry of the B-Cl-H subsystem is still poorly known, this work is aimed at its determination, combining detailed modeling and experimental measurements.

This paper will present results on the ab-initio study by the G3B3 computational method. Potential energy surfaces have been generated for numerous reaction paths, and have allowed to identify transition states, from which reaction rates have been deduced using the canonical variational transition state theory or the RRKM theory. Then, a coherent gas-phase species and reaction set is obtained and inserted in a chemical kinetic solver for validation.

The model results are compared to IRTF data on the low-pressure decomposition of BCl3/H2 mixtures obtained in a tubular furnace featuring a hot-zone.
BP-35 Thermal and Tribological Investigation of Al2O3-Thin Films for Their Use in Cutting Operations
K. Bobzin, N. Bagcivan, P. Immich, S. Bolz, M. Ewering (RWTH Aachen University, Germany)
Crystalline PVD γ-Al2O3- coatings offer great potential for their use in high-speed cutting operations. They promise high hot hardness and high oxidation resistance at elevated temperatures. In this regard γ-Al2O3- thin films were sputtered on WC/Co- samples using pulsed MSIP (Magnetron Sputter Ion Plating) PVD technology. To study the phase stability and the oxidation behaviour of the deposited coatings annealing tests in vacuum and atmosphere at different temperatures were carried out. The samples were analyzed by X-ray diffraction, Scanning Electron Microscopy (SEM) and nanoindentation for the mechanical properties. Additionally, application oriented tests (Pin-On-Disc (POD) measurements) were performed to characterize the coating’s high temperature wear behaviour. As counter part materials, two different hard-to machine materials (Inconel 718 and austenitic alloy X5CrNi18-10) were used. For the investigations different samples temperatures were used (RT, 600°C, 800°C and 1000°C). The wear tracks and the wear areas on the pins were analyzed by SEM. The investigated coatings showed an extraordinary thermal stability during the annealing and oxidation tests. Also the behaviour during the Pin-On-Disc investigations allows us to believe that the PVD γ-Al2O3 coatings showed good premises for their use in cutting operations.
BP-37 Investiation of Substrate Bias Effects on the Reactively Sputtered ZrN Diffusion Barrier Films
J.-L. Ruan (National Cheng-Kung University, Taiwan); D.-F. Lii (Cheng Shiu University, Taiwan); J.S. Chen, J.-L. Huang (National Cheng-Kung University, Taiwan)
Zr-N diffusion barrier films were prepared by DC reactive magnetron sputtering under different substrate bias voltages. Cu films were subsequently sputtered onto the Zr-N films without breaking vacuum. The composition, microstructure, resistivity and diffusion barrier properties of Zr-N films with respect to substrate bias were studied by means of x-ray diffraction, electron probe microanalyzer, x-ray photoelectron spectroscopy, Auger electron spectrometer and four point probe method. Results showed that the deposition rate and chemical composition of Zr-N films were substantially influenced by the resputtering effect due to the ion bombardment on the film surface, which was induced by the substrate bias addition. The increase of substrate bias also decreased the resistivity and enhanced the diffusion barrier performance of films against copper. The biased Zr-N films could effectively prevent diffusion of Cu to SiO2 wafer even up to the high temperature of 800 oC for 30 minutes.
BP-38 Microstructuring of Superhard Pulsed Laser Deposited ta-C Films Using Excimer and Femtosecond Laser Pulses
G. Reisse, S. Weissmantel, D. Rost, R. Boettcher, M. Nieher, A. Engel (University of Applied Sciences Mittweida, Germany)
Several micrometer thick superhard tetrahedral amorphous carbon (ta-C) films prepared by pulsed laser deposition on polished steel and hard metal substrates have been microstructured using (1) excimer laser pulses of 248 nm wavelength and 30 ns pulse duration and (2) femtosecond laser pulses of 775 nm mean wavelength and 130 fs pulse duration. The aim was to investigate if and how various microstructures can be produced in those films without changing their diamond-like properties and whether those microstructures can be used for the creation of optical effects. Furthermore, the influence of various microstructures on the tribological properties and the wear resistance of the films were investigated. By using the excimer laser well defined gratings with the width and depth of the grooves as well as the grating space in the range of 0.5 to a few micrometer were produced. By using the femtosecond laser so-called ripple structures, which resemble gratings with a spacing of some 0.5 µm, were produced in the films. This method can be used to microstructure swiftly relatively large areas of the films. The microstructures have been investigated with respect to their appearance and their dimensions by Scanning Electron and Laser Scanning Microscopy, the results of which will be shown. Moreover, the influence of the different microstructures on tribological and wear performance of the films measured by using a commercial tribotester under various conditions will be presented.
BP-39 Silicon Dioxide Films Fabricated by an End-Hall Ion Source Using Hexamethyldisiloxane
T. Ichinohe (Tokyo National College of Technology, Japan); M Ooshima, K. Harada, N. Akasaka, S. Masaki, K. Kawasaki (TDY, Inc., Japan)
Hexamethyldisiloxane (HMDSO) has been widely employed for many applications, using another gas mixed, for instance, oxygen, nitrogen etc, such as protective, optical, hard coatings, and/or selective gas permeation membranes. HMDSO can have the advantage of inorganic/organic hybrid films for flexible electronics, which need a low temperature deposition process. An end-hall ion source has been employed for low temperature deposition process with low energy ion beam. In this study, we attempted to fabricate silicon dioxide films with HMDSO by a low energy ion beam assisted plasma deposition using the end-hall ion source. Argon (Ar) gas was used for plasma generation, and both HMDSO and oxygen gas flowed into the Ar plasma generated by the end-hall ion source. A 90 % transparent film was deposited in this process. The fabrication of stoichiometric SiO2 was shown in XPS study, in addition to a sharp Si-O stretching mode shown in IR study.
BP-41 Effects of Indium-Doped on the Crystallization and Optical Properties fo ZnO Thin Films Prepared by the Sol-Gel Method
K.-J. Chen, S.-J. Chang, F.-Y. Hung (National Cheng Kung University, Taiwan); T.-H. Fang (National Formosa University, Taiwan)
ZnO and indium-doped ZnO (IZO) thin films were prepared on the quartz glass by sol-gel method. Multipurpose X-ray thin film diffraction (XRD), scanning electron microscopy (SEM), dual-beam focused ion beam (DB-FIB) and photoluminescence (PL) were used to analyze the ZnO and IZO thin films. The results were also compared to investigate the structural characteristics and optical properties. The surface morphology of ZnO thin films was different from that of the IZO thin films. The ZnO thin film had a fine particle-like structure and the shape of the IZO showed a whisker-like, not a particle-like appearance. Notably, the structure of the IZO thin film was looser than that of the ZnO thin film, resulting in the obvious variations on the number of cavities. From the XRD, the ZnO and IZO thin films possessed the hexagonal structures, however the In2O3 phase was observed in the IZO thin films. The photoluminescence spectra of ZnO and IZO thin films showed a strong UV emission band and a green emission band. Indium-doped decreased the crystalline quality of IZO thin film, however the In2O3 phase and the distribution of fine-cavities improved the PL characteristics.
BP-42 Plasma Over-Treatment Effect on MOCVD-TiN Contact Glue Layer
S.-C. Chang, J.K. Huang (National Cheng Kung University, Taiwan); Y.-L. Wang (Taiwan Semiconductor Manufacturing Company Ltd., Taiwan)
In a semiconductor-device process, in-situ hydrogen/nitrogen plasma treatment was commonly used to improve the quality of metallorganic-chemical-vapor-deposition titanium nitride (MOCVD-TiN) films for the application of contact glue layers. This study found that overloaded plasma-treatment energy induced an increase in the contact resistance (Rc) of pattern wafers. One of possible reasons was that overloaded plasma power loosened the density of TiN films resulting in more external oxygen diffusing into the film to form a high-resistance oxidation layer. An offline plasma-treatment index calculated from the reciprocal of under-treated TiN sheet resistance divided by the thickness of a non-treated TiN film was developed to monitor inline Rc. The physical concept of the index is the received plasma energy per unit TiN thickness. The offline plasma-treatment index linearly correlated to the Rc of pattern wafers as the MOCVD-TiN film was over treated by plasma.
BP-43 Synthesis and Characterization of Multilayer CrN/ZrN Thin Films Using Closed-Field Unbalanced Magnetron Sputtering Process
M.G. Kim, S.Y. Lee (Korea Aerospace University, Korea); W.Y. Jeung (Korea Institute of Science and Technology, Korea); J.J. Lee (Seoul National University, Korea)
In this study, multi-layered CrN/ZrN films with various bilayer periods (?) were deposited using an unbalanced magnetron sputtering process. Composition, microstructure and surface morphologies were characterized by auger electron spectroscopy (AES), X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The mechanical properties of these coatings were characterized by nanoindentation, scratch tester and wear tester and compared to those of single-layer CrZrN with various Zr contents. The hardness of films were dependent upon the bilayer period (?) and the maximum hardness and elastic modulus of approximately 31.8 and 321.5 GPa, respectively were measured from the thin film with a bilayer period of 2 nm. The compressive residual stress in the coating increased as the bilayer period decreased in the ranges from 2.0 to 2.7 GPa. Also, result from wear tests showed multi-layered CrN/ZrN films exhibited good wear resistance properties than that of conventional CrN film. However, the wear resistance of multi-layered CrN/ZrN films was inferior to that of single-layer CrZrN films.
BP-45 Thermal Stability and Oxidation Resistance of (Cr,Al)N Based Coatings Deposited by Cathodic Arc Method
H. Hasegawa (Okayama University, Japan); H. Ezura, N. Fukumoto (Keio University, Japan); K. Ohashi, S. Tsukamoto (Okayama University, Japan); T. Suzuki (Keio University, Japan)

Transition metal nitrides have been widely used in applications such as cutting tools, protection wear and machinery components, because of their superior tribological, chemical and physical properties. (Cr,Al)N has gained much attention as a substitute for (Ti,Al)N, and has been investigated with respect to, microstructure, mechanical properties, thermal stability, and cutting performance. Recently, we developed the newly (Cr,Al)N based films by adding foreign metal such as Y and Si, which are expected to lead formation of stable oxide and amorphous at elevated higher temperature. From the XRD results of samples after vacuumed annealing, incorporation of Si and Y to (Cr,Al)N prevented Cr2 N phase segregation at 800 ºC; and cubic phase stability was better than (Cr,Al,Si)N and (Cr,Al,Y)N.

In this study, (Cr,Al,Y)N, (Cr,Al,Si)N and (Cr,Al,Si,Y)N were annealed under vacuum or air pressure with ranging from 800 to 1100°C. Changes in micro-hardness and microstructure as a function of annealing temperature were studied and discussed based on X-ray diffraction method, electron microscopy.
BP-47 Comparison of the Corrosion Resistance of Commercial Multilayers TiAlN, AlCrSiN, AlCrN and CrN Coatings
L. Gil (Unexpo Vicerectorado Puerto Ordaz, Venezuela); E. Le Bourhis (Universite de Poitiers,Laboratoire de Métallurgie Physique, France); L. Jimenez (Universidad Nacional Experimental Politécnica (UNEXPO), Venezuela); E.S. Puchi, M.H. Staia (Universidad Central de Venezuela)
The corrosion behaviors of commercial multilayers TiAlN, AlCrSiN, AlCrN and CrN coatings deposited on a steel substrate using a commercial PVD cathodic arc process were studied in a 3,5 % sodium chloride solution by using open circuit potential and potentiodynamic polarization measurements. Surface characterization and morphological characteristics of the coatings before and after the corrosion test was performed using techniques such as scanning electron microscopy (SEM) with an energy- dispersive X- ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy. The potentiodynamic polarization measurements showed that for all the coatings the corrosion potential shifted to higher values as compared to the uncoated substrate. Similarly, the corrosion current density decreased for coated samples, indicating better corrosion resistance. The results showed that the aqueous corrosion behavior of the nitride coatings is strongly dependent both on the structural defects that appear during processing and on the incorporation of the interfaces such as TiN coatings, which modify their corrosion behavior and, therefore, improve their performance in these aqueous environments.
BP-48 Deposition Process Analysis of Chromium Nitride Thin Films Using Taguchi Experimental Design Method
J.-W. Lee, C.M. Chen, J.C. Huang (Tung Nan University, Taiwan); L.-C. Chang (Huafan University, Taiwan); J.-S. Yang (Tung Nan University, Taiwan)
Taguchi experimental design method is popular to analysis the influence of deposition parameters on characteristics of thin films due to its efficiency and easy to operation. In this work, chromium nitride thin films were prepared by a bipolar symmetric pulsed DC reactive magnetron sputtering system. Deposition parameters including the substrate bias, pulse frequency of substrate bias, substrate heating temperature and Ar/N2 ratio were selected as variables. The Taguchi method was used to develop experimental arrays for each coating. The structures of chromium nitride films were characterized by an XRD. The surface and cross sectional morphologies of thin films were examined by a scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface roughness of thin films was explored by an atomic force microscopy (AFM). The Daimler-Benz Rockwell-C adhesion and scratch tests were further conducted to evaluate the adhesion properties of coatings. A number of trends were identified using Taguchi analysis method. It is observed that a chromium nitride coating with sufficient hardness can be achieved through the following deposition parameters: substrate bias of -200V and 80 kHz in bias frequency, 250°C substrate temperature, and an Ar/N2 ratio of 2:1.
BP-49 Corrosion Rsistance of Multi-Elemental Nanocrystalline Nitride Based Sputtered Coatings
O. Jimenez, M. Audronis, A. Leyland, A. Matthews (University of Sheffield, United Kingdom)
Hard thin coatings containing transition-metal nitride or boride phases offer superior properties including high hardness, high melting point and chemical inertness. ZrN and (Zr,Ti)N coatings have demonstrated superior tribological behaviour and represent very promising candidates for applications related to improved protection against corrosion, high temperature wear and oxidation resistance. In this paper thin PVD ZrTiB(N) ceramic coatings were successfully deposited onto silicon wafer and mirror-polished 316L stainless steel, using medium frequency (20-350 kHz) asymmetric bipolar pulsed magnetron sputtering (PMS) technology. A rectangular target composed of three pieces (Zr/TiB2/Zr) under different deposition conditions of bias voltage and N2 flow rates was used for deposition purposes. The structure, morphology, mechanical properties and corrosion resistance of the films have been studied by means of GAXRD, cross-sectional scanning electron microscopy images, nanoindentation measurement and potentiodynamic polarization resistance. SEM images revealed that these coatings were fully dense, featureless and defects-free. Structural analysis resulted in a solid solution (Zr,Ti)N single phase with (111) preferred orientation. Hardness values above 20 GPa were measured for most of the coatings deposited at different N2 flow rates, while hardness for those containing no nitrogen was found to be lower, the corrosion resistance of coatings was found to be better than uncoated and zirconium nitride samples under certain conditions of deposition parameters.
BP-50 Low Resistance, Transparent and Flexible Amorphous ITO Electrode Grown by Roll-to-Roll Sputtering System
K.-H. Choi, H.-K. Kim, S.-W. Cho (Kumoh National Institute of Technology, Korea)
Low resistance, transparent, and flexible amorphous Sn doped In2O3 (ITO) electrode was grown by a roll-to-roll sputtering system on PET substrate for use in flexible organic light emitting diodes and solar cells. For the deposition of high quality ITO electrode at room temperature, a specially designed roll-to-roll sputter system with cooling drum and substrate winding/unwinding system was employed. It was found that electrical and optical properties of ITO electrode are critically dependent on the DC power, working pressure, Ar/O2 ratio and rolling speed. Under optimized growth conditions, a sheet resistanc of 22.5 Ω/square and average transmittance above 85 % in a visible range were obtained even for the ITO electrode film grown at room temperature. Moreover, the ITO/PET sample showed stable mechanical properties during the bending test due to stable amorphous structure of ITO layer. This indicates that ITO electrode grown by a roll-to-roll sputtering system is promising flexible and transparent electrodes for flexible OLEDs and flexible solar cells.
BP-51 High-Performance Phosphorescent Organic Light-Emitting Diodes Prepared Using an Amorphous Indium Zinc Oxide Anode Film Grown by Box Cathode Sputtering
H.-K. Kim (Kumoh National Institute of Technology, Korea); J.-W. Kang (Korea Institute of Materials Science (KIMS), Korea)
The preparation and characteristics of amorphous indium zinc oxide (a-IZO) anode films grown using a plasma damage-free box cathode sputtering (BCS) technique for use in phosphorescent organic light-emitting diodes (OLEDs) is described. The electrical, optical, structural, and surface properties of the a-IZO anode, which was prepared by BCS at room temperature, were comparable to those of commercial ITO anode films. In addition, the work function of the ozone-treated a-IZO anode (5.23eV) was much higher than that of an ozone-treated commercial ITO anode (4.95 eV). Due to high work function and transmittance of the BCS-grown a-IZO anode, Ir(ppy)3-doped phosphorescent OLED prepared on the BCS-grown a-IZO anode films showed identical or better electrical and optical properties than OLEDs prepared on a commercial ITO anode film. In particular, both the quantum efficiency (16.3 %) and power efficiency (40.7 lm/W) of the Ir(ppy)3-doped phosphorescent OLED fabricated on the amorphous IZO anode film was much higher than the quantum efficiency (12.4 %) and power efficiency (30.1 lm/W) of an OLED with a commercial ITO anode. This indicates that a-IZO anode prepared by BCS technique affords OLED performance that rivals or exceeds that of devices fabrication with commercial ITO anode, even though it was prepared at room temperature.
BP-52 Plasma Damage Free Sputtering of Al Cathode on Organic Light Emitting Diodes Using Twin Target Sputtering With Ladder Shape Magnet Array
J.-A. Jeong, H.-K. Kim (Kumoh National Institute of Technology, Korea)
Twin target sputtering (TTS) system with a configuration of vertically parallel facing Al targets and a substrate holder perpendicular to the Al target plane has been designed for realization of a direct Al cathode sputtering on organic light emitting diodes (OLEDs) without plasma damages. The TTS system has a linear twin target gun with ladder type magnet array for effective and uniform confinement of high density plasma. It is shown that OLEDs with Al cathode deposited by the TTS show much lower leakage current density (~1* 10-5mA/cm2) at reverse bias of -6V, compared to that (1*10-2~10-3 mA/cm2 at -6V) of OLEDs with Al cathodes grown by conventional DC magnetron sputtering. In addition, it was found that Al cathode films prepared by TTS were amorphous structure, due to low substrate temperature. This demonstrates that there is no plasma damage caused by the bombardment of energetic particles. This indicates that the TTS system with ladder type magnet array could be useful plasma damage free deposition technique for direct Al cathode sputtering on OLEDs or flexible OLEDs.
BP-53 Formation of Low Resistance Ni-Alloy Ohmic Contact to Pentacene for Organic Thin Film Transistors
H.-K. Kim (Kumoh National Institute of Technology, Korea); J.-H. Jang, J.-J. Kim (Seoul National University, Korea); J.-A. Jeong (Kumoh National Institute of Technology, Korea)
Organic thin film transistors (OTFTs) have been studied extensively in the past decades due to their advantages such as mechanical flexibility, low processing cost to large scaling. Although great progress has been achieved in the area of pentacene based OTFTs, many problems still remains such as the low mobility of OTFTs and lack of high quality ohmic contact on pentacene semiconductors. In particular, to realize commercialized OTFTs, high quality ohmic contacts are required. However, detailed studies of alloy ohmic contacts to pentacene have not been widely conducted until now. In this work, we report on a Ni-Au metallization scheme for producing low-resistance ohmic contact to pentacene for organic thin film transistors (OTFTs). Ni-Au alloy contact exhibits linear current-voltage characteristics, showing a high-quality ohmic contact is formed. Co-evaporated Ni-Au alloy contact on a pentacene layer shows lower specific contact resistivity (5.6*10 -2 Ω-cm2), calculated from transmission line model (TLM) method, than contact resistivity (9.354 Ω-cm2), of conventional Au contact. In addition, it was found that the transfer characteristics of OTFTs are critically influenced by metal-pentacene contact resistance as well as channel resistance. Using x-ray photoelectron spectroscopy and synchrotron x-ray scattering examinations, a preliminary explanation for Ni-Au ohmic contact formation is described.
BP-54 Functionally Graded Nano Structured TiNi Shape Memory Thin Films
D. Kaur, A. Kumar (Indian Institute of Technology Roorkee, India)
To improve the properties of TiNi films, multi-layer, composite or functionally graded TiNi based films were fabricated on Si (100) substrate via dc magnetron sputtering. Two separate Ti and Ni targets were used and film stoichiometry was precisely controlled by varying the power to each target. Compositionally graded films were deposited at various substrate temperatures ranging from room temperature to 650°C. The accompanying changes in the microstructure and growth morphology of the phases in these films were investigated in detail using X-ray diffraction and an atomic force microscopy. The effect of film thickness on the texture development of the films was also studied using XRD and FESEM. AFM based in-situ characterization was performed to see the phase transformation behavior. With change of temperature, the microstructure and surface roughness values changes drastically, which reveal the phase transformation between martensite and austenite phases. The surface roughness of the martensite phase was found to be much higher than that of the austenite phase. Further the two way SMA behaviour was inferred from electrical transport studies in these graded TiNi thin films. In addition multilayer composite of CrN/TiNi/CrN was fabricated and thickness and size induced effects of CrN layer on structural and phase transformation properties of underneath TiNi layer were investigated.
BP-56 A Novel Pulsing Method for the Enhancement of the Deposition Rate in High Power Pulsed Magnetron Sputtering
S.-H. Seo, J.-H. In, H.-Y. Chang (Korea Advanced Institute of Science and Technology, Korea)

The high power pulsed magnetron sputtering (HPPMS) has been suggested as the promising technology for the enhancement of the ionization rate of sputtered atoms in 1999. The potential of this technology has attracted keen interest because it can transiently produce high-density plasma with high electron-impact excitation efficiency during the pulse-on period. However, the HPPMS has the fatal drawback that the deposition rate is extremely low even though it depends on the target material. In this presentation, a novel pulsing technique will be proposed for the enhancement of the sputtering rate of the target material in the HPPMS. In the new pulsing method, two pulses of the high-voltage HV pulse with the peak voltage of about -1.7 kV and the pulse width of about 5 µms and the low-voltage LV pulse with the minimum voltage of 500 V and the pulse width of 10 µms were sequentially applied to the cathode. The repletion frequency of the resulted cathode pulse was 10 kHz and so, the pulse-off duration was about 80 µms. Using the dual pulse with only an additional low voltage pulse, we could obtain the deposition rate of the Ti film more than two times higher than that in the single high-power pulse discharge. The mechanism on the enhancement of the deposition rate will be discussed from the time-resolved diagnostic results.

1The authors would like to thank the Engineering and Research Center (grant no. R11-2000-086-03007-0) for their financial support of this research.

2The company Plasmart Ltd. Is specially acknowledged for the technical support and the supply of probe acquisition system (SLP2000$super ®$).
BP-57 Study of Thin Film Deposition Conditions in Various Types of Magnetron Discharges
P. Jedrzejowski, S. Navala, C. Cote, C. Robado, A. Sarkissian (Plasmionique Inc., Canada)
A control of ion to neutral atom flux ratio is an important factor in thin film synthesis. Magnetron sputtering of thin films is a deposition process characterized by a possibility of decoupling various plasma parameters, giving a high degree of control over the ion and neutral atom fluxes. It makes magnetron sputtering a versatile technique for various film - substrate combinations. Plasma characteristics in the near substrate region is of a particular interest, since it determinates the conditions of thin film growth. In this work we study thin film growth conditions in plasma discharges created in various types of magnetic field configurations, namely: balanced and unbalanced in RF and DC discharges. We control the energetics of substrate surface reactions by modifications of magnetic field distribution in the discharge zone. For a DC discharge of 200 W in 9 mTorr of Ar we obtain a variation in ion current density from 4.9*10-2 mA/cm2 to 1.8*10-1 mA/cm2 measured at the distance of 100 mm from the target. Plasma density and plasma potential distribution are related to the ratio of ion to atom fluxes for different locations on a substrate holder.
BP-58 Effect of Hydrogen Content on the Corrosion Resistance of DLC Coating on 316L for Biomedical Implants
L. Jimenez (Universidad Nacional Experimental Politécnica (UNEXPO), Venezuela); M.H. Staia, E.S. Puchi (Universidad Central de Venezuela); J. Marcuzzo (Instituto Tecnológico de Aeronáutica ITA, Venezuela)
The 316L austenitic stainless steels are very attractive and well-known materials for biomedical applications However, its practical tribological use is limited due to the presence of wear debris in the contact which can cause a harmful biological reaction with the tissue inside the body and can ultimately destroy its corrosion barrier passive layer. A significant advance was made with the use of the application of DLC films due to their properties such as high hardness, chemical inertness and low friction. In the present work, DLC coatings were deposited on 316L stainless steel by using two coatings systems: an RF planar PECVD producing hydrogenated amorphous carbon (a-C:H) and a DC magnetron sputtering, used to obtain non-hydrogenated amorphous carbon coatings, respectively. The coatings corrosion resistance was evaluated by conducting potentiodynamic polarization curves and electrochemical impedance spectroscopy, both in a solution which simulated the human body environment (0.89% NaCl solution of pH 7.4 at 37°C). Scanning electron microscopy (SEM) and Auger electron spectroscopy techniques were employed for the coatings morphological characterization before and after the corrosion test in order to identify the possible mechanisms of corrosion. The potentiodynamic polarization measurements showed that for the coatings studied, the corrosion potential (Ecorr) was shifted towards a more positive potential and the corrosion current density (icorr) decreased when the hydrogen content in the DLC coatings increased, improving significantly their corrosion performance.
BP-59 Investigation of the Microstructure and Characterizations of TiN/CrN Nano-Multilayer Deposited by Unbalanced Magnetron Sputter Process
C.-Y. Su, T.-P. Liou (National Taipei University of Technology, Taiwan); J.-S. Su (Lang Yang Institute of Technology, Taiwan); P.-T. Chen (Pentad Scientific Corporation, Taiwan); C.-K. Lin (Feng Chia University, Taiwan)
In the present study, TiN, CrN, and TiN/CrN multilayer thin films were deposited onto WC substrates by DC magnetron sputtering. Single layer TiN or CrN thin film was prepared by different nitrogen flow rate (20-30 sccm). TiN/CrN multilayers with a monoyaer thickness of 25 nm or 4 nm were also deposited. The overall thickness of TiN, CrN, or TiN/CrN multilayer thin film was controlled to ~1 micron. The morphology, and crystalline structures of the as-prepared films were characterized by SEM and XRD. While, mechanical properties, thermal stability and oxidation resistance of the as-prepared films were characterized. The results show that the growth of column grains and void defects could be restrained when the substrate bias was -100 V. When nitrogen flow rate was increased from 20 to 30 sccm, TiN structure remained. While, ß-Cr2N transformation to CrN can be noticed. Interdiffusion of TiN/CrN multilayer thin film (prepared by a monolayer thickness of 4 nm) can be noticed. The hardness was ~23.9 and 21.4 GPa for TiN and CrN thin film, respectively. A significant increase to 34.9 GPa for TiN/CrN multilayer thin film (4 nm interval) can be observed. The scratch tests results show a similar trend. The critical load for TiN/CrN multilayer thin film was 45.1 N and was higher than that of TiN (~24.8 N) or CrN (~36.3 N).
BP-61 Controlled Fluorination of a-C:F:H Films by PECVD of Ethylene-Hexafluorobenzene Mixtures
B.B. Bellotti (Universidade Estadual Paulista, Brazil); C.U. Davanzo (Universidade Estadual de Campinas, Brazil); W. Schreiner (Universidade Federal de Parana, Brazil); S.F. Durrant (Universidade Estadual Paulista, Brazil)
Highly fluorinated plasma polymers are chemically inert, acid resistant and have low friction coefficients, thereby being useful in chemical laboratories and for tribological applications. Here we report the plasma polymerization of ethylene-hexafluorobenzene mixtures in a cylindrical reactor equipped with horizontal, circular, internal electrodes and excited with rf power (13.56 MHz, range up to 300 W). The principal parameter of interest is the proportion of C6F6 in the feed, RF. Films were deposited onto aluminum-covered glass slides for subsequent analysis using near-normal and grazing-angle Fourier Transform Infrared Spectroscopy. The latter technique is particularly useful for detecting modes not usually observed at near-normal incidence. Groups such as CH, CFx (x = 1 to 3) and OH may thus be detected. In addition to these qualitative analyses, X-ray Photoelectron Spectroscopy (XPS) was used to investigate the presence of fluorinated groups in the films as a function of RF. For these analyses films were deposited onto aluminum substrates. From the XPS spectra, groups such as CH, CF and CF2 may be detected by deconvolution of the C1s peak. Atomic ratios of F:C obtained from the XPS spectral data reveal that the degree of fluorination may be controlled by the choice of RF. Contact angle measurements showed increased surface hydrophobicity at greater values of RF. We thank the Brazilian agencies FAPESP and MCT/CNPq for financial support.
BP-62 GaN-Core/SiOx-Sheath Nanowires
H.W. Kim, J.W. Lee, H.S. Kim, M.A. Kebede, M.H. Kong (Inha University, Korea)

Since the discovery of carbon nanotubes, much technological and scientific excitement has been raised by the discovery of various forms of nanostructures. Recently, coaxial nanocable-like one-dimensional (1D) structures comprising different kinds of materials have been successfully synthesized not only for making nanometer scale electronic devices with a variety of functions, but also for the protection of 1D structures from contamination or oxidation. Hexagonal gallium nitride (GaN), an important semiconductor with a wide-band-gap of 3.4 eV at room temperature, is an ideal material for the fabrication of blue light-emitting diodes and laser diodes. On the other hand, the formation of SiOx sheaths, which exhibit excellent insulating characteristics on the exterior of nanowires, is essential not only to avoid interference between building blocks of a complex nanoscale circuit, but also to protect nanowires from contamination. In particular, the insulating SiOx sheath is required to fabricate field effect transistors and sensor devices based on nanowires. Furthermore, the SiOx coating layer is optically transparent for the visible absorption/emission of semiconductor nanowires, resulting in limited destruction of their intrinsic optical properties. Since the three-dimensional geometry with respect to bundles of 1D structures requires high degree of the process control for achieving the conformal coating, it is worth developing suitable growth method. For potential application to ultra-large-scale-integration (ULSI) fabrication requiring a simple and well-controllable process, the feasibility of using two-step process was investigated.

In this study, pre-grown GaN nanowires were coated via a sputtering technique using a Si wafer as a target. We have investigated comparatively the samples before and after the coating in terms of their structural and photoluminescence (PL) characteristics. This novel approach to fabricate the nanowire heterostructures will be a step toward the potential applications of composite nanowires to nanodevices.
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