ICMCTF2007 Session BP: Symposium B Poster Session

Thursday, April 26, 2007 5:00 PM in Room Town & Country

Thursday Afternoon

Time Period ThP Sessions | Topic B Sessions | Time Periods | Topics | ICMCTF2007 Schedule

BP-2 Microstructure and Mechanical Properties of Ti-Si-C-N Films Synthesized by a Plasma-Enhanced Chemical Vapor Deposition S. Abraham, K.H. Kim, E.Y. Choi (Pusan National University, Korea) Quaternary Ti-Si-C-N films were synthesized on AISI 304 stainless steel and Si wafer by an RF- PECVD technique using a gaseous mixture of TiCl₄, SiH₄, CH₄, Ar, N₂, and H₂. The temperature for coating was maintained constant at 600. The microstructure and mechanical properties of the coatings were largely affected by the addition of Si content. The Si addition into Ti-C-N coating resulted in the modification of microstructure and mechanical properties and our quaternary Ti-Si-C-N coatings had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by an amorphous phase of Si₃N₄. The micro-hardness of the coatings increased from ~24 GPa of Ti-C-N and reached to a maximum hardness of ~45 GPa of Ti-Si(9.2 at.%)-C-N film. In this work, a systematic investigation of the microstructure and mechanical properties of Ti-Si-C-N coatings were conducted through various instrumental analyses.
BP-3 MgO Growth by Liquid Injection Chemical Vapor Deposition: Experiments, Modeling and Simulation S. Thollon (CEA, France); M. Pons (INP Grenoble, France); M. Manin (CEA, France); H. Rouch (INOPRO, France) Magnesium oxide layers were deposited using the pulsed liquid-injection metal-organic chemical vapour deposition technique. The deposition has been carried out in oxidizing conditions using a single molecular source: magnesium [bis(2,2,6,6 tetramethyl-3,5-heptanedionate)] (Mg(thd)2). The structure, composition and morphology of the magnesia films were analysed by different techniques. A trend based analysis of two-dimensional (2D) heat and mass transport coupled with surface chemistry and gas phase reaction including clustering and decomposition was developed to simulate this growth. Verification of the model was carried out by comparison of the computations with the previously presented experimental data. The model gave a macroscopic characterization of transport phenomena, particularly the competition between deposition and gas-phase nucleation. The model was applied to the design of a large reactor, with showerhead arrangement and a substrate of 200 mm in diameter.
BP-4 Energetic Balance and Kinetics for the Decomposition of Supersaturated Ti_1-xAl_xN P.H. Mayrhofer, F.D. Fischer (Montanuniversität Leoben, Austria); H.J. Böhm (Vienna University of Technology, Austria); C. Mitterer (Montanuniversität Leoben, Austria); J.M. Schneider (RWTH Aachen University) Ti_1-xAl_xN films have been shown to exhibit superior mechanical and thermal properties and are thus widely used for industrial applications. We have recently reported, that metastable NaCl-structure (c) Ti_1-xAl_xN decomposes to form c-TiN and c-AlN domains, and that the chemical requirement for spinodal decomposition is fulfilled over a broad composition and temperature range. Ab initio calculations showed that the maximum metastable solubility limit of AlN in c-TiN is in the range of 0.64 - 0.74, depending on the configurational entropy. The enthalpy change for decomposition of supersaturated c-Ti_1-xAl_xN into c-TiN and c-AlN has a maximum of ~0.146 eV/at (28.18 kJ/mol) at x ~0.61. Here, we use continuum mechanical investigations in addition to ab initio calculations to consider also the previously not described contribution of strain and surface energy on the energetic balance for this decomposition process. For a fully constrained condition the elastic strain energy has a maximum of 2.99 kJ/mol at x = 0.50. The specific interface energy γ between formed c-TiN, c-AlN and matrix is estimated by using the nearest-neighbour-broken-bond hypothesis and has a maximum of 0.183 J/m² at x = 0.65. Based on these results a simple kinetic model for the decomposition process of c-Ti_1-xAl_xN can be developed.
BP-5 Pulsed DC Magnetron Sputtered Al₂O₃ Films and Their Hardness M. Sridharan, A.M. Ejsing, J. Bottiger, H. Birkedal (University of Aarhus, Denmark) Al₂O₃ films were deposited by magnetron sputtering and their hardness was measured by nanoindentation. The magnetron was powered with a pulsed DC power supply, and the substrate was negatively biased with a pulsed DC voltage supply. To be able to vary the flux of energetic ions hitting the film during deposition, an RF coil was placed between the magnetron and the substrate to create a plasma with the intensity independent of the deposition rate, i.e. the flux of ions hitting the growing film was controlled independently of the rate of growth of the film. As measured with transmission electron microscopy and X-ray diffraction, the films were amorphous in the temperature range investigated, 200 to 600°C, when the low-flux ion bombardment only originated from the plasma formed in front of the magnetron. At 200°C, with increasing ion bombardment small crystalline grains of gamma Al₂O₃ of the order of 10 nm in size became imbedded in the amorphous matrix. A further increase of the ion bombardment and/or higher temperatures result in a larger fraction of crystalline material embedded in the amorphous phase. A systematic study of the dependence of the nanostructure on the RF power, (average) bias voltage and substrate temperature was carried out, and the hardness of the various films was measured with nanoindentation. The hardness of the single-phase amorphous films varied from 7 GPa to 9 GPa, depending on the atomic density. Adding the crystalline gamma Al₂O₃ phase to the amorphous phase, the hardness increased up to 20 GPa. The measured hardnesses were correlated with the corresponding nanostructures.
BP-6 Copper Film and Anode Temperature Distribution Measurements in a Vacuum Arc with Tungsten Anode I.I. Beilis, A. Shnaiderman, A. Shashurin, R.L. Boxman, S. Goldsmith (Tel-Aviv University, Israel) Copper films deposited by a radially expanding plasma plume from a hot refractory tungsten anode vacuum arc were investigated. The arc was sustained between a consumed water-cooled cylindrical Cu cathode (30mm diameter) and a non-consumed W cylindrical anode (32mm diameter, 30mm height) that was heated by the arc. Temperature was measured for gap lengths h=5 and 10mm. Arc currents I=150-300A were applied for periods of up to 180s. The films were deposited on glass substrates which were exposed to the plasma plume while a shutter was open. Distances to substrate from the electrode axis (L) were 80 and 110mm. The anode temperature was measured at three points in the anode body (2, 12 and 22 mm from the front surface) by high temperature W/5%Re-W/26%Re thermocouple probes located at points T1, T2 and T3 respectively. The film thickness was measured by a profilometer, and MP surface density was determined using an optical microscope. The anode temperature, film thickness distribution, deposition rate, and MP size distribution function were measured and compared to previous results obtained using a molybdenum anode. It was observed that for I=200A, L=110mm, h=10mm the number of MPs in the A-region (facing the anode) decreased with MP size. The MP size distribution in the A-region of the coated film had a similar distribution to that obtained with a Mo anode, but the MPs surface density was about 30% less. The deposition rate at L=80mm, h=10mm and I=200A was about 2µm/min (for a 30s deposition starting 90s after arc ignition), similar to that obtained previously with a Mo anode. The anode temperature increased with time and reached in steady state about T1~2300K for both W and Mo anodes for low current 150A. The temperature increased with arc current for W anode (T1~2450K for I=200A and 2650K for I=300A). A larger surface temperature can be reached using higher current for W anode due to it lower rate of vaporization than for Mo anode.
BP-7 Structural and Magnetic Studies of La_2/3Ca_1/3MnO₃/LaNiO₃ Artificial Superlattices Prepared by rf Magnetron Sputtering H.-J. Liu, H.-Y. Lee (National Synchrotron Radiation Research Center, Taiwan); C.-W. Yu, C.-H. Lee (National Tsing Hua University, Taiwan) Magnetic oxide superlattices consisting of the ferromagnetic oxide La_2/3Ca_1/3MnO₃ and paramagnetic oxide LaNiO₃ have been successfully grown on SrTiO₃ substrate by rf magnetron sputtering technique. The structural and magnetic properties of a series of samples in which the La_2/3Ca_1/3MnO₃ layer thickness is fixed at 7.5 nm and that of LaNiO₃ varied from 1.5nm to 7.5 nm. X-ray reflectivity and high-resolution x-ray diffraction measurements were employed to characterize the microstructure of these films. The azimuthal scan around surface Bragg peak of the film shows that the epitaxial relationship between film and substrate. The clearly discernible main feature and satellite features observed in the (002) crystal truncation rod indicate the high quality of the La_2/3Ca_1/3MnO₃/ LaNiO₃ artificial superlattice structure have been formed on a SrTiO₃ substrate. Hysteresis measurements show magnetic properties are highly correlative with interfacial strain between substrate and film. The indications of antiferromagnetic interlayer coupling have been found in La_2/3Ca_1/3MnO₃/LaNiO₃ multilayers as the space layer varied. The smaller LaNiO₃ spacer thickness is, the larger is the in-plane lattice strain of the films presented; the larger the saturation magnetization is, the smaller is the magnetic coercivity field.
BP-8 Magnetic Properties and Nanostructures of Fe Based Alloy Thin Film G.J. Chen, L.S. Tseng, P.T. Chiang, J.S.C. Jang, Y.H. Shih (I-Shou University, Taiwan) In the experiment, the multiple targets (Fe, Pt and Pd) were used to deposit Fe/Pt/Pd multilayers on Corning 7059 glass substrate and Pt/Ti/Si/SiO₂ substrate by DC sputter. The composition of Fe100PtxPd100-x thin films was controlled by adjusting the thickness of each layer. As deposited films were then post annealed at temperatures range of 300-600 for 30 minutes. The nanostructure and the magnetic properties of the FePtPd films were investigated .The structure of Fe/Pt/Pd multilayers have been studied by glancing angle X-ray diffraction method. As the post annealing temperature increased to higher than 400, the structure become ordering. The magnetic properties of Fe/Pt/Pd multilayers have been investigated by Vibrating Sample Magnetometer (VSM) and Perpendicular Magnetic-Optical Kerr Effect (PMOKE) measurement. After post annealed at 600, the films obtained the highest in-plane and/or out-of-plane coercivity with x=75. The Hc and Hc are 7.5 kOe and 5.9 kOe respectively. By the application of buffer layer, the ordering temperature of L10 phase reduced to 400 and the coercivity increased further.
BP-9 Mechanical Properties and Thermal Stability of CrN/AlN Multilayer Thin Film Coatings J.K. Kim, E.Y. Kim, M.G. Kim, S.Y. Lee (HanKuk Aviation University, Korea) In this work CrN/AlN superlattice coatings with various bilayer periods (lamda) were synthesized using closed-field unbalanced magnetron sputtering(CFUBMS) method and their thermal stability behaviors as a function of bilayer periods ((lamda) in the range of 2nm to 13nm were investigated. The bilayer period (lamda) was controlled by changing rotation speed of the substrate holder. The crystalline structure, chemical composition, microstructure and mechanical properties of CrN/AlN superlattice films have been studied with transmission electron microscopy (TEM), X-ray diffractometry (XRD), Scanning electron microscope (SEM), Auger electron spectroscopy (AES), Scratch test and nano-indentation test. In order to evaluate the thermal stability, the CrN films and CrN/AlN superlattice films were annealed at temperature between 600°C and 1000°C for 30min in vacuum chamber. CrN/AlN superlattice film with a bilayer period (lamda) of 4nm showed the maximum hardness and elastic modulus of approximately 37.6 and 417 GPa, respectively which was 1.54 times higher than the hardness predicted by the rule of mixture from CrN and AlN coating. Annealing Experiments showed that the CrN/AlN superlattice films have a superior thermal stability to those of CrN films due to the presence of alternating AlN thin films. This thermal stability of thin film improves as the bilayer period (lamda) of the superlattice film decreases. Thin films with a 2nm bilayer period maintained its microhardness of more than 30 GPa after annealing 30 min. at 800°C. Detailed experimental results will be presented.
BP-10 Hardness and Residual Stress in Nanocrystalline ZrN Films: Effect of Bias Voltage and Heat Treatment H.-M. Tung, J.-H. Huang (National Tsing Hua University, Taiwan); D.-G. Tsai, C.-F. Ai (Institute of Nuclear Energy Research, Atomic Energy Council, Taiwan); G.-P. Yu (National Tsing Hua University, Taiwan) The purpose of this study was to investigate the effects both bias voltage and heat treatment on the composition, microstructure, and associated mechanical properties of the zirconium nitride (ZrN) thin films deposited on AISI 304 stainless steel substrates by a filtered cathodic arc ion-plating (FAC-IP) system. The depositions were carried out by varying negative substrate bias voltage, from –40 V_b to –80 V_b. The deposited film specimens were heat-treated at 800°C for 1 hour. X-ray diffraction (XRD) revealed (a) texture coefficients of (111) plane increased with negative bias, and (b) the grain size was of approximately less than 15nm, i.e. nano-scale grain size. The hardness of the deposited ZrN films was correlated with point defects, (111) texture coefficient, and crystallinity characterized for the films. For the as-deposited films, it was found that the hardness increased with decreasing (111) FWHM and increasing (111) texture coefficient, suggesting a better crystallinity and lower grain boundary mobility in the highly textured films. The decrease in film hardness after heat treatment may be attributed mainly to the reduction of point defects present in the films. Measurement performed for the intrinsic residual stress reported a significant 5.5 GPa release in the heat-treated films, due to recovery of point defects by heat treatment.
BP-11 Structural and Mechanical Properties of Cr(C,O) Thin Films Synthesized by a Cathodic Arc Deposition Process Y.Y. Chang, S.-J. Yang, D.-Y. Wang (Mingdao University, Taiwan) Chromium carbide and chromium oxide coatings deposited by physical vapor deposition methods have been successfully applied in molding industries for their excellent tribological performances. In addition, nanocomposite coatings have recently attracted much interest because of their high hardness, wear resistance, and good thermal and chemical stability. In this study, Cr(C,O) nanocomposite coatings were synthesized by cathodic-arc evaporation with plasma enhanced duct equipment. A carbon-oxide reactive gas was introduced to react with chromium to form Cr(C,O) nanocomposite coatings during the deposition process. The effect of carbon and oxygen content on the microstructure and mechanical properties of Cr(C,O) nanocomposite coatings were studied. Emission spectra of the plasma in front of the Cr cathodes were recorded using an in-situ optical emission spectrometer. In this study, field emission scanning electron microscope, transmission electron microscope and X-ray diffraction using Bragg-Brentano and glancing angle parallel beam geometries were used to characterize the microstructure and stress of the deposited films. The composition and chemical bonding of deposited Cr(C,O) coatings were evaluated by X-ray photoelectron spectroscopy. Hardness, Young's modulus and adhesion strength of the coatings were determined by nano-indentation and Rockwell indentation methods. It has been found that the mechanical properties of the films were correlated with the nanocomposite structure.
BP-12 High Temperature Oxidation Resistance and Electrical Properties of Cr-Al-Si-N Coatings Synthesized by a Cathodic-Arc Deposition Process Y.Y. Chang, C.-P. Chang, D.-Y. Wang (Mingdao University, Taiwan) The high temperature oxidation resistance and surface electrical conductivity of the CrN and Cr-Al-Si-N coatings were studied. These coatings were deposited on SS304 and silicon substrates by using a cathodic-arc deposition system with lateral rotating arc cathodes. Chromium and Al₈₉Si₁₁ cathodes were used for the deposition of Cr-Al-Si-N coatings. For the high temperature oxidation test, the coated samples were annealed between 600°C to 1000°C in air. In this study, field emission scanning electron microscope, transmission electron microscope and X-ray diffraction using Bragg-Brentano and glancing angle parallel beam geometries were used to characterize the microstructure of the as-deposited and annealed films. The composition and chemical bonding of the deposited Cr-Al-Si-N coatings were evaluated by X-ray photoelectron spectroscopy. The oxidation kinetics of the deposited coatings showed parabolic behavior, indicating that the diffusion process occurred during oxidation. The high temperature oxidation resistance and surface conductivity of the CrN films can be improved by the formation of composite Cr-Al-Si-N. It has been found that the high temperature oxidation and electrical properties of the deposited films were correlated with the alloy content and nanocomposite structure.
BP-13 Effect of Sputtering Gas Pressure on Structural, Electrical, and Optical Properties of ZnO:Al Thin Films T.-Y. Tseng (National Chiao Tung University, Taiwan); S.-N. Bai (Chienkuo Technology University, Taiwan); F.-C. Chuang (National Chiao-Tung University, Taiwan) The properties of transparent conductive Al2O3 doped ZnO thin films grown by R.F. magnetron sputtering method were investigated. Argon gas working pressure is changed from 2.5 to 40 mTorr to investigate its effect on the properties of ZnO:Al thin films at room temperature. The microstructure of ZnO:Al films is influenced obviously by changing the Ar pressure. It is shown that the grain size of ZnO:Al films decreased with the increasing Ar pressure. The X-ray diffraction patterns indicate that the worse crystallized structure of ZnO:Al thin films is obtained at higher Ar pressure. Moreover, the highly (002)-oriented ZnO:Al thin films can be found at the whole range of Ar pressure. The growth rate of the films decreases from 1.5 nm/min to 0.5 nm/min as the Ar gas pressure increases from 2.5 to 40 mTorr. The optical transmittance measurements of ZnO:Al thin films reveal a high transmittance (>80%) in visible region and exhibit a sharp absorption edge at wavelength about 350nm. From the variations of absorption edge with Ar pressure, it is indicated that the optical bandgap of the ZnO:Al films is slightly dependent on Ar pressure.
BP-14 The Effect of Bombarding Conditions on the Properties of Multifunctional Ti-C-O Thin Films Grown by Magnetron Sputtering A.C. Fernandes, P. Carvalho, L. Cunha (Minho University, Portugal); Ph. Goudeau, J.P. Riviere (Poitiers University, France); F. Vaz (Universidade do Minho, Portugal) Reactive sputtered titanium oxide and titanium carbide thin films have been extensively investigated because of their remarkable optical, electrical, mechanical and chemical properties. The possibility to join both appears to be an important issue in order to find new and multifunctional applications for a combined material: titanium oxycarbide, TiC_xO_y. Taking this into account, the main purpose of this work consists in the study of the effect of the ion bombardment on the properties of multifunctional Ti-C-O thin films, grown by reactive magnetron sputtering. The depositions were carried out from a Ti target with incrusted C peaces, varying the bias voltage from grounded condition up to -150 V. The oxygen flow rate was kept constant at 4 sccm. The obtained results show that the composition of the films presented some variations, revealing some preferential resputtering of C. X-ray diffraction results showed a progressive amorphization of the samples with increasing negative bias voltages, which is probably the result of the formation of an oxide phase. This amorphization resulted also in an increase in electric resistivity of the samples. Mechanical behaviour characterization showed an increase in hardness when preparing the films with a negative bias voltage. Grounded sample has a hardness value of about 17 GPa, while negative biased samples revealed hardness values around 20 GPa.
BP-15 Optimization of Magnetic Field Configuration and Erosion Zone Profile in Planar Axisymmetric Magnetron S. Navala, C. Cote, P. Jedrzejowski, A. Sarkissian (Plasmionique Inc., Canada) Magnetron sputtering is one of the most popular methods of physical vapor deposition for thin films. The most important advantages of this technique include the high deposition rate, the versatility for depositing pure or composite materials from solid targets, on any type of substrate and the environmentally friendly nature of the technology. However, the technique suffers from one main disadvantage, which is its relatively poor target utilization efficiency. Generally, improving cathode design would require elaborate 3D Monte Carlo simulations. In this work we have attempted to determine the erosion profile for a given magnetic geometry, using analytical models combined with numerically evaluated magnetic field profiles. The approach allows rapid evaluation of the influence of changes in magnetic field geometry on erosion profile. In order to validate this approach, we compare the measured profiles with those predicted from the model. In particular we discuss the results of a novel design, which has a compressed magnetic field at the target's surface. This magnetron is characterized by a double magnetic trap, and a wide erosion profile. The measured target utilization for the optimized magnetic field distribution is up to 50% for a two-inch target.
BP-16 Effect of Ion Enhance on Ti1-xAlxN Thin Films Deposited by Rf-Reactive Sputtering Y.-W. Lin, J.-H. Huang, G.-P. Yu (National Tsing Hua University, Taiwan) This paper deals with the Titanium aluminum nitride (Ti_1-xAl_xN)thin films prepared by rf-reactive sputtering technique. TiAlN films were sputtered respectively from Ti and Al target in the environment of Ar and N₂ mixture. The effect of ion enhanced were investigated on the microstructure and properties of TiAlN films .In terms of phase formation, three types of coatings were considered: (a) a TiAlN single-phase solid solution, (b) TiAlN interlacing nucleus of AlN in the matrix, and (c) nanocomposite TiAlN films including a significant fraction of hcp-AlN phase. The films were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindenter. The type (a) shows weakly columnar structure, but the type (b) exhibited refined columnar structure has excellent hardness that can be attributed to the grain refinement. The hardness measurement shows that the microstructure feature was the major factor in determining the property of the thin films.
BP-17 A Comparison of the Performance of Planar and Cylindrical Magnetrons Operating in Pulsed DC and AC Modes P.J. Kelly, G.T. West, Y.N. Kok (Manchester Metropolitan University, United Kingdom); J.W. Bradley, I. Swindells (University of Liverpool, United Kingdom); G.C.B. Clarke (Manchester Metropolitan University, United Kingdom) The deposition of functional films onto both polymeric web and large area glass substrates has been a major area of growth in recent years. The key to this growth has been the development of the mid-frequency (20-350 kHz) dual bipolar pulsed magnetron sputtering process, which now permits complex, multi-layer structures with specific properties to be routinely deposited in high throughput systems. There are, though, several competing variants of the dual bipolar process currently employed, with each variant imposing its own set of criteria in terms of cost, process stability, throughput and product performance. Commercially available coating systems utilise both planar and cylindrical rotatable magnetrons, driven by AC, or pulsed DC power supplies. Few direct comparisons, though, have been made of these alternative approaches. Consequently, selection of equipment and operating procedures are being made largely on an empirical basis, potentially leading to non-optimal deposition conditions, or reduced film functionality. In this study, therefore, titania and silica coatings have been deposited by reactive magnetron sputtering onto glass substrates in both magnetron configurations and power delivery modes. The films have been analysed in terms of their structures and properties using an extensive suite of techniques, including SEM, XRD, WDAX, nanoindentation and scratch testing. Furthermore, the operating characteristics of the competing technologies have also been studied in terms of process stability, power dissipation and the nature of the plasma generated. The results to date of this extensive study are reported here.
BP-18 The Properties of Al Doped ZnO/Ag/Al Doped ZnO Multilayer Thin Film Prepared by Facing Targets Sputtering Method S.M. Kim, B.J. Cho (Kyungwon University, Korea); M.J. Keum (Center for Advaced Plasma Surface Technology, Korea); H.W. Choi, H.H. Yoon, S.J. Park, K.H. Kim (Kyungwon University, Korea) We have studied the properties of Al doped ZnO (AZO)/Ag/AZO multilayer thin films deposited on glass and polyethersulfon substrate. AZO/Ag/AZO thin films were prepared with different thickness of Ag layer at 1mTorr, input power (DC) of 100W and room temperature without any substrate heating by facing targets sputtering method. To investigate the properties, we used four-point probe, UV/VIS spectrometer with a spectral range of 300-1100nm, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and atomic force microscope (AFM). We obtained AZO/Ag/AZO thin film of low resistivity in most of the thin films. We could prepare AZO/Ag/AZO thin film with average transmittance of over 80% in the visible range (400-800nm) when we deposited Ag layer with a specific thickness. With increasing the thickness of Ag layer, increasing the crystallinity of Ag layer was observed.
BP-19 Mechanical Properties and Thermal Stability of Ultra-Fine bcc Ta and V Coatings A.F. Jankowski, J.P. Hayes (Lawrence Livermore National Laboratory) The strength of metals is known to scale, in general, with a decrease in grain size according to the Hall-Petch relationship. Ta and V coatings, nanolaminates, and bulk material with nanoscale grain size are reported to show ^1-3 an increase in strength and microhardness by a order-of-magnitude above fully homogenized materials. We now assess the intermediate regime of grain size effects on both strength and hardness. In the micron to submicron scale, ultra-refined microstructures of both V and Ta are produced using both electron-beam evaporation and magnetron sputtering deposition techniques. Sample strength is measured under uniaxial tension using a pull tester and hardness is measured by Vickers microindentation. Grain size is determined from optical micrographs of cross-sections by linear intercept measurements. We find that the mechanical properties inversely scale with square-root grain size according to Hall-Petch from the macro- through the micro- to the nano- scale. Also, samples are characterized in the as-deposited condition and subsequent to high-temperature vacuum anneal treatments to assess the thermal stability of the ultra-fine microstructure and quantify the kinetics of grain growth. The diffusivity and activation energy for grain growth are determined identifying the temperature transition in dominant mechanism from grain boundary to lattice diffusion. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. ¹Wei, et al., Scripta Mater. 50 (2004) 359 ²Zhang, et al., Scripta Mater. 54 (2006) 1227 ³Jankowski, et al., LLNL Rpt. UCRL-JRNL-223669 (2006) 25 pp .
BP-20 Microstructure and Electrical Characteristics with Ferroelectric (Ba,Sr)TiO₃ Thin Films and HfO₂ Buffer Layer for the Non-Volatile Memory Application L.-C. Chang (Huafan University, Taiwan); C.-C. Ho (National Chiao-Tung University, Taiwan) In order to form metal-ferroelectric-insulator-semiconductor (MFIS) structure, barium strontium titanate (BST) and hafnium oxide (HfO₂) films were deposited on Si(100) substrate. The results of the fabrication and the characterization of the MFIS structure on the silicon substrate were reported. The novel structures used a hafnium oxide (HfO₂) as the buffer layer, while HfO₂ is one of the most promising materials in replacing SiO₂ as the gate dielectric due to the high temperature stability on Si, the high dielectric constant, and low interfacial defect with Si. The HfO₂ intermediate layer between BST films and Si substrate prevents BST from the serious inter-diffusion into Si substrate. The memory window was about 2.2 V for sweeping bias from -10V to 10V and from 10V to -10V, and the electrical properties of those films on Si substrate were studied. The leakage current density was about 1x10^-7A/cm² at the writing voltage. Besides, the microstructures of the MFIS structures were showed in the work. The excellent ferroelectric characterizations make Pt/BST/HfO₂/Si structure attractive for practical ferroelectric memory field effect transistor applications.
BP-21 Characterization of Cr-Doped TiO₂ Thin Films Prepared by Cathodic Arc Plasma Deposition M.-H. Chan (National Chung Hsing University, Taiwan); W.-Y. Ho, D.-Y. Wang (Mingdao University, Taiwan); F.-H. Lu (National Chung Hsing University, Taiwan) In this study, Cr-doped TiO₂ films were prepared by co-sputtering of titanium and chromium in a cathodic arc plasma deposition system. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and atomic force microscopy were used to characterize obtained thin films. Adding another metallic component in TiO₂ might shift the absorption edge from an ultraviolet to a visible region. As-deposited pure titanium dioxide thin films exhibited an anatase structure as revealed by XRD. However, Cr-doped TiO₂ films possessed an amorphous structure. The chemical states of Cr-doped TiO₂ films were also investigated by XPS and Raman spectroscopy. After annealing at 450°C for 3 hours, the structure of Cr-doped TiO₂ films transformed from an amorphous to a rutile crystalline structure. The film roughness increased as well. Changes in the morphology of the films were also examined by FE-SEM. The water contact-angle was measured under different light spectra. The contact angle decrease to nil after 15 minutes under visible illumination. That indicates the absorption edge of Cr-doped TiO₂ films shifted from an ultraviolet to a visible (500~570 nm) region.
BP-22 Effects of the Inserted-Cr Layer Thickness on Electrical Characteristics of a Novel Sandwich Capacitor C.-C. Ho, B.-S. Chiou (National Chiao-Tung University, Taiwan); L.-C. Chang (Huafan University, Taiwan) A novel sandwich capacitor of Ba_0.7√sub0.3TiO₃/Cr/Ba_0.7√sub0.3TiO₃was sputtered onto Pt/Ti/SiO₂/Si substrate. With the insertion of Cr thickness ranged from 2nm to 15nm, the electrical properties of Pt/BST/Cr/BST/Pt were improved significantly. The temperature coefficient of capacitance (TCC) of specimens with BST/Cr(2nm)/BST capacitor can achieve about 69% lower than those with mono-BST layer. In a parallel work, the results indicated the formation of the TiO₂ secondary phase was found after the novel sandwich structures were annealed at 800°C in O₂ atmosphere. Therefore, the negative value of TCC of BST can be compensated by the positive TCC of TiO₂, and a temperature stable dielectric can be achieved. The voltage stability of BST could be significantly improved with the insertion of Cr layer, and VCC of BST/Cr/BST capacitor can decrease to 21% of mono-BST capacitor's one. However, the dielectric constant slightly decreases as Cr thickness increases. The root causes for the improvement of TCC, VCC, dissipation factor, and leakage current density of BST/Cr/BST parallel plate capacitors with Cr layer of various thicknesses are investigated.
BP-23 Aluminium Oxide Coatings by Remote Plasma Sputtering A. Pilkington, A.L. Yerokhin, A. Leyland (University of Sheffield, United Kingdom); M.A. Baker (University of Surrey, United Kingdom); A. Matthews (University of Sheffield, United Kingdom) Physical vapour deposition of aluminium oxide has received significant attention in recent years, with research primarily directed towards the production of hard crystalline alumina deposits at moderate temperatures. Alpha phase alumina is considered to have the most stable chemical and mechanical properties, making this alumina phase most desirable for engineering coating applications. Deposition of alpha alumina has been reported for a variety of PVD systems using the templating technique based on chromia underlayers. This work reports reactively sputtered alumina coatings fabricated using a remote plasma technique in a HITUS S400 cryo pumped PVD system. Coatings were deposited in a temperature range of 100-500 C using floating and bipolar pulse bias modes. The hysteresis characteristics of the remote plasma sputtering of AlO_x from a metallic target is investigated for varying ratios of Argon to Oxygen in the pressure range 0.1-1 Pa. The morphologies of coatings deposited on substrates of 316SS, ASP23 and Silicon wafers were characterised by optical microscopy and SEM. Surface profilometry was used to characterize surface roughness Ra and Rz. Phase composition was investigated by XRD. The mechanical properties were characterised by nanoindentation, Vickers microhardness and scratch adhesion testing.
BP-24 Detaching Mechanism for Mo-Ru Hard Coating on Tungsten Carbide L.-C. Chang (Huafan University, Taiwan); Y.-I. Chen (Ether Precision Inc.); J.-W. Lee (Tung Nan Institute of Technology, Taiwan); H.-Y. Lin (Huafan University, Taiwan) Hard coating materials were widely applied on top surface of the molding dies to extend lifetime and enhance the mechanical properties for glass molding mass production. The glass molding process can be recognized as both a cyclic thermal aging treatment and a high temperature oxidation process to the die materials. Thus, to remove damaged coating resulted from production injury is as important as to deposit it on the molding die. In this study, the Mo-Ru hard films selected as the protective coatings with Cr and Ti twin interlayers were deposited on tungsten carbide substrates by direct current (DC) sputtering technique to improve the characteristics of molding die material. The as-deposited coatings were crystallized in a feature of nanoscale morphology. Chemical etching process was performed to remove the hard coating for recycling process. The etching process was monitored by the observation of atomic force microscopy. It was clarified that the hard coating was etched to bore some holes in the beginning, then Cr interlayer and grain boundary of Mo-Ru coating became the paths for etching process to perform easily. On the other hand, the Ti interlayer was effective to protect the erosion of tungsten carbide substrate.
BP-25 Influences of Nitrogen Partial Pressures on Structure, Mechanical and Corrosion Properties of TiSiN Coating Synthesized by Cathodic Arc Plasma Evaporation C.-T. Lin, C.-L. Chang, W.-Y. Ho, D.-Y. Wang (Mingdao University, Taiwan) Nanocomposite TiSiN films have been deposited on M2 tool steel substrates using TiSi-target arc sources by a dual cathodic arc plasma evaporation system. The influences of the nitrogen pressure 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 nanocomposite TiSiN thin films. The corrosion behavior of coatings was investigated using polarization and immersion tests. The results showed that the hardness of the films ranged from 25-37 GPa, which the value is higher than that of TiN (21 GPa). The coefficient of steady-state friction of the films against both Cr steel and WC-Co ball ranged from 0.6 to 0.7, and TiN is 0.7. It has been found that the microstructure, mechanical, wear, and corrosion properties of the films were correlate to nitrogen pressure, grain size, and amorphous Si3N4 nanocomposite formed in film structure, resulting from a superhard of TiSiN coatings.
BP-26 Effect of Glass Substrate Temperature on Electrical Properties of Ga-Doped ZnO Films Prepared by Ion-Plating using DC Arc-Discharge T. Yamada, A. Miyake, S. Kishimoto, H. Makino, T. Yamamoto (Kochi University of Technology, Japan) Transparent conducting Ga-doped ZnO (GZO) films have been deposited on alkali-free glass substrate by ion-plating using dc arc-discharge technique. In our previous works¹, we reported that, by optimizing Ga₂O₃ contents in ZnO source and oxygen gas flow rates, GZO films (Ga₂O₃ content: 4 wt.%) having comparable resistivity to Sn-doped In₂O₃ (ITO) were obtained at substrate temperature of 473 K: a resistivity of 4.4 x 10^-4 Ωcm and 1.8 x 10^-4 Ωcm for GZO films with thickness of 30 nm and 560 nm, respectively. In this study, the effect of glass substrate temperature on electrical properties of GZO films have been investigated to obtain optimum quality films having lower resistivity, high transmission and high-heat resistance. The substrate temperature was varied in the range from 423 to 673 K. Hall effect measurements showed that, with increasing substrate temperature to 473-523 K, the resistivity of GZO films with a thickness of 200 nm decreases to 2.1 x 10^-4 Ωcm and then increased gradually with further increases in temperature, reaching 5.6 x 10^-4 Ωcm at 673 K. Increasing substrate temperature monotonically reduced carrier concentration. Hall mobility increased from 23 to 30 cm²/Vs with increasing substrate temperature to 573 K and then turned to decreases with further increases in temperature. We will discuss on the formation of defects and/or impurities such as Zn vacancy and non-conducting Ga oxides in the grain or at the grain boundary, suggested from the behavior of electrical properties described above. ¹Proceedings of 6th International Conference on Coatings on Glass and Plastics, pp 335-338 (2006).
BP-27 Microstructural and Mechanical Characterization of Sputtered ZrN-TiB₂ Thin Coatings O. Jimenez, A. Matthews, A. Leyland (University of Sheffield, United Kingdom) Physical Vapour Deposited hard coatings are of interest for improving mechanical and functional properties of a diverse variety of tools and component materials. Because of their well-known high melting point, high hardness and chemical inertness, TiB₂ and ZrN are very promising candidates for applications related to wear, high temperature and oxidation resistance. In this article, results are discussed from thin ZrN-TiB₂ coatings onto Si-wafer and polished ASP23 tool steel deposited by magnetron sputtering techniques using a target composed of three pieces (Zr-TiB₂-Zr). High purity N₂ gas has been used as a reactive gas at different flow rates to promote the formation of Zr nitride as a second hard phase in the film. The coatings were evaluated by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy for microstructural evaluation. Nanoindentation measurements were taken in order to establish the relationship between the mechanical properties such as hardness and elastic modulus with the different parameters used for the deposition process (eg. N₂ content). The Rockwell C hardness test was also selected as qualitative method for adhesion evaluation.
BP-28 Effects of Nitrogen Partial Pressure on Electrical Properties and Thermal Stability of TiAlN Films by Ion Beam Sputter Deposition S.-Y. Lee (National Cheng-Kung University, Taiwan); S.-C. Wang (Southern Taiwan University, Taiwan); J.-S. Chen, J.-L. Huang (National Cheng-Kung University, Taiwan) (Ba,Sr)TiO₃ (BST) dielectric films have attracted great attention for potential use as capacitors in dynamic random access memory (DRAM). As far as we know, this is the first time that TiAlN films prepared by ion beam sputter deposition (IBSD) were used as both the bottom electrode and diffusion barrier for metal-insulator-metal (MIM) BST capacitor application. Our previous study had shown the effects of ion beam voltage, substrate temperature on electrical properties and thermal stability of TiAlN films. In this paper, effects of nitrogen partial pressure (PN2) during IBSD process on the TiAlN films properties and how they affect the electrical resistivity and thermal stability were investigated. It was found that PN2 affects the crystallographic structure, crystallinity, compositions of the films and result in different performance in electrical resistivity and thermal stability. As the PN2 increased, the electrical resistivity increased with decreasing of degree of predominance in (200) plane and the crystallinity of films. It is believed that the diminishing of degree of predominance in (200) and crystallinity of the films are attributed to a decreased kinetic energy of adatoms with increasing PN2. The thermal stability of TiAlN films also decreased as the PN2 increased. Thermal stability is decreased with the decreasing Al content and the crystallinity of films. It is worth to mention that due to the dense film quality nature of the IBSD method, the TiAlN films deposited at optimum condition (PN2=4.4 x10-3Pa ) exhibits good thermal stability up to 700°C in oxygen atmosphere and the resistivity can still remains lower than 500μΩ×cm.
BP-29 Corrostion Behavior of Commercial Nanolayered and Multilayers TiAlN Coatings L.E. Gil (Universidad Nacional Experimental Politecnica (UNEXPO), Venezuela); M.H. Staia (Universidad Central de Venezuela, Veneauela); E. Puchi (Universidad Central de Venezuela); S. Liscano (Universidad Nacional Experimental Politecnica (UNEXPO), Venezuela); E. Le Bourhis, D. Eyidi (Université de Poitiers, France) This study was performed with the aim of evaluating the corrosion performance of (Ti_1-xAl_x)N coatings commercially deposited on WC inserts. The (Ti1-xAlx)N/TiN multilayers, nanostructured and single layer coatings, which contained different Ti/Al atomic ratios varying from 7/3 to 2/3, respectively, were deposited by employing a commercial PVD cathodic arc process. The corrosion performance was evaluated in a 3,5 % sodium chloride solution by using open circuit potential and potentiodynamic polarization measurements. Surface characterization before and after corrosion testing was performed using scanning electron microscopy (SEM) with an energy- dispersive X- ray analysis (EDX) and X-ray diffraction (XRD). The (Ti_1-xAl_x)N multilayers coating and the nanostructured coatings present the better corrosion resistance. The results indicated that the aqueous corrosion behavior of the nitride coatings is strongly dependent on the structural defects such as pores, pinholes and cracks that appear during processing. The nanolayered structure would improve the coating density, closing the possible access paths of the aggressive environment to the substrate and, then, improving the corrosion resistance of the coating. In the order hand, the incorporation of interfaces in a multilayer (Ti_1-xAl_x)N/TiN coating modifies the corrosion behavior. As the number of interfaces increases, more micro-pores are blocked and, therefore, an improvement of their corrosion resistance is achieved.
BP-30 Reactive ECR-Plasma Sputtering of Aluminium Oxide A. Matthews, M. Audronis, T. Pilkington, A. Leyland (University of Sheffield, United Kingdom) An inherent potential drawback of sputter deposition processes is that the degree of ionisation achieved, and the energy state of the deposition species, are generally critically dependent on the plasma characteristics of the sputter source itself. Of course, developments such as unbalanced magnetrons, and high power pulsing systems have considerably enhanced the performance of sputter deposition processes. Nevertheless, especially for certain coatings which present problems in terms of the achievement of the required ion energies and fluxes, there remains a need to "decouple" the ionisation-enhancement system from the sputter source. In our laboratory, we are studying various techniques to achieve this, and in this paper the method reported is to use a microwave ECR-plasma sputtering system. We operate this in a configuration which allows the ECR plasma to pass through a ring-shaped sputter target (providing an intense source of ion bombardment), and to impinge on the substrate surface, thereby providing deposition ion energies and fluxes which can be controlled over a wider range than achievable using other available systems. We discuss the plasma characteristics of the system and report enhanced aluminium oxide coatings obtained using it. We also discuss the drawbacks of the system, in terms of its directional nature and the influence on deposit uniformity.
BP-31 Corrosion Behavior of PAPVD CrN Coating on Plasma Nitrided AISI H13 Steel S. Liscano, L.E. Gil (Universidad Nacional Experimental Politecnica (UNEXPO), Venezuela); M. Cruz, M.H. Staia (Universidad Central de Venezuela); O.A. León (Polytechnic Experimental National University (UNEXPO), Venezuela); E.S. Puchi-Cabrera (Universidad Central de Venezuela); E. Le Bourhis (Université de Poitiers, France) The aim of this work was to investigate the corrosion behavior of physically vapor deposited CrN coatings on plasma nitrided AISI H13 steel. The samples were pre-nitrided using experimental equipment in two different N₂/H₂ gas mixtures, i.e. 25%N₂ and 75%N₂ and, subsequently, CrN coating was deposited commercially by a PAPVD process. The corrosion resistance of these duplex coating systems was assessed using electrochemical measurement techniques coupled with scanning electron microscopy (SEM) technique to analyze the samples surfaces before and after testing. The experimental results indicate that duplex coating systems possess superior corrosion resistance over the individually plasma nitrided or PVD coated H13 steel. The duplex coating system with 75% N₂ nitriding conditions resulted in the maximum corrosion resistance. It was also shown that nitriding led to an increase of the free corrosion potential and that the compound layer on the surface acted as a barrier against corrosion attack.
BP-32 Thin Films Deposition by PECVD Method for Low- k Materials and Characterization of Their Electrical and Mechanical Properties I.-S. Bae, S.-J. Cho, J.-H. Boo (Sungkyunkwan University, Korea) Organic-Inorganic hybrid polymer-like thin films have been deposited on glass and silicon substrates under the several condition such as different annealing temperature, the ratio of ethylcyclohexane and TEOS and RF power by plasma enhanced chemical vapor deposition(PECVD) method using single molecular precursors of the organic-inorganic hybrid polymers. Ethylcyclohexane and TEOS (tetraethylorthosilicate) were utilized as organic and inorganic precursors, and hydrogen and Ar (argon) were used as a bubbler and carrier gases, respectively. In order to compare the difference of the electrical and the mechanical properties of the plasma polymerized thin films, we grew the hybrid polymer-like thin films under the conditions of various RF (radio frequency using 13.56 MHz) powers in the range of 20~60 W and annealing temperatures with 200^oC~500^oC. The as-grown polymerized thin films were in first analyzed by FT-IR, UV-Visible spectroscopy, SEM, and AFM. The result of FT-IR and UV-Visible measurement showed that the plasma polymerized thin films have highly cross-linked density with increasing RF power, TEOS ratio, and deposition temperature. AFM and SEM also showed that the polymer films with smooth surface and sharp interface could be grown under various deposition conditions. Impedance analyzer was utilized for the measurements of I-V and C-V curves. From the electrical properties measurements, the lowest dielectric constant and best leakage constant were obtained to be 2.67 and 10^-10 A/cm² at 1MV/cm, respectively.
BP-34 Effects of sp³ Contents on the Quality of Amorphous Diamond-Like Carbon by Filter Arc Deposition Y.-C. Chen (National Chung Hsing University, Taiwan); K.-W. Weng (MingDao University, Taiwan); S. Han (National Taichung Institute of Technology, Taiwan); F.S. Shieu (National Chung Hsing University, Taiwan); H.C. Shih (National Tsing Hua University, Taiwan) Various researches of the diamond-like carbon (DLC) films have been focused on the commercial applications such as hard disk, tool industries, protective optical materials, biomedical products, etc. In this research, the amorphous DLC films have been deposited by filter arc deposition (FAD) with different target currents on various substrates. The properties of DLC films are examined by X-ray photoelectron spectroscopy, Raman scattering spectroscopy, field emission scanning electron microscopy, I-V curves and Hall measurement. The qualities of the DLC films are found to be adequate for the application with a controllable varying thickness and atomistic smooth surface. To sum up, the sp³ C-C bonds of the DLC films are proportional to the electric conductivity.
BP-35 The Hardness and Oxidation Behavior of Ti_1-xAl_xN/VN Nanoscale Multilayered Coatings J.K. Park, Y.J. Baik (Korea Institute of Science and Technology, Korea) Ti_1-xAl_xN coatings have been used as a protective surface layer of many types of machine parts and tools. Although the addition of Al in TiN improved oxidation rersistace, the hardness was reported to decrease with increase in Al contents over a critical value. In this respect, therefore, Ti_0.5Al_0.5N coating has mainly been used for coating materials. By nanoscale multilayered structurization with CrN, however, Ti_1-xAl_x, even AlN has been reported to show higher hardness as well as better oxidation resistiace, in comparison to the single layer coatings such as TiN, AlN, Ti_0.5Al_0.5 and CrN due to the superlattice formation. Such a superlattice formation is very effective way in increasing hardness of coatings with excellent oxidation resistance but low hardness. In metal nitride based coatings, the oxidation resistance of VN was reported to be excellent, due to the low oxidation temperature around 600°C. In this study, the hardness and oxidation behavior of Ti_1-xAl_xN/VN nanoscale multilayered coatings have been investigated. Ti_1-xAl_xN/VN nanoscale multilayered coatings were prepared by reactive D.C. magnetron sputtering with Ti_1-xAl_x alloy and V targets. Bilayer period of nanomultilayer was controlled by changing rotation speed of substrate holder. The Ti_1-xAl_xN/VN superlattice coatings were annealed at different temperature from 600°C to 800°C to investigate oxidation resistance of the coatings. Effect of bilayer period on the crystalline structure, hardness and oxidation behaviors of the Ti_1-xAl_xN/VN suprelattice coatings will be discussed. This research was supported by a grant(code #: 06K1501-00720) from 'Center for Nanostructured Materials Technology' under '21st Century Frontier R&D Programs' of the Ministry of Science and Technology, Korea.
BP-36 Effects of Bias Voltage and Temperature on Mechanical Properties of Cr-Si-N Coatings Deposited by a Hybrid System of Arc Ion Plating and Sputtering Techniques S.J. Heo, J.H. Yun, K.H. Kim (Pusan National University, Korea) Cr-Si-N coatings were deposited on AISI D2 substrates by a hybrid coating system of arc ion plating (AIP) and sputtering techniques. Effects on deposition temperature and substrate bias voltage on the microstructure and mechanical properties which include microhardness, indentation elastic modulus of Cr-Si-N coatings were systematically investigated in this work. As the deposition temperature increased up to 300, microhardness and indentation elastic modulus of the Cr-Si-N coating steadily increased. Higher temperature above 350, however, caused the microhardness to decrease due to grain growth. The substrate bias voltage had an effect on the Si content in Cr-Si-N coating. Applying a small substrate bias voltage of -100 to Cr-Si-N coatings induced compressive residual stress into the coating and made its microstructure denser due to ion bombardment effect. However, much higher substrate bias voltage of -350 caused the diminution of Si content by re-sputtering phenomenon, which could result in a decline of nanocomposite characteristics of Cr-Si-N. The superior mechanical properties of the Cr-Si-N coatings were obtained at the deposition condition of 300 -100V.
BP-37 CrB₂ Coatings Deposited by Inductively Coupled Plasma - Assisted DC Magnetron Sputtering H.S. Choi, B. Park, J.J. Lee (Seoul National University, Korea) CrB₂ coatings were synthesized on high speed steel(HSS) substrates by inductively coupled plasma(ICP)-assisted DC magnetron sputtering at different ICP powers (0~400W), and substrate bias voltages (ground~-20V). The mechanical properties such as the hardness and adhesion were measured by a micro-indenter and CSEM scratch tester. Corrosion properties of the coatings were investigated with an EG&G 273A potentiostat in a pH 7, 0.8 M NaCl solution and pH 0.90 0.25M H₂SO₂ . The structure of the CrB₂ coatings was analyzed by X-Ray diffractometer (XRD). The thickness of the CrB2 coatings maintained at 2µm for the whole range of the deposition condition. The effect of the ICP power on the structure of the coating was discussed with the property changes of films such as microstructure, hardness, and corrosion resistance. And the effect of ICP etching on the adhesion property was also investigated. The preferred orientation of CrB₂ coatings has changed from (101) to (001), where (001) has a better corrosion property than (101), with increasing ICP power. The hardness of the CrB₂ coatings also increased with increasing ICP power and negative substrate bias, from 34.57GPa up to 46.62GPa. The adhesion of film was enhanced for about 10 N through ICP etching changing the surface condition of the substrate.
BP-38 Effect of Microstructures on Electrical and Photoluminescent Properties of Nanocrystalline Ta-Si-N Thin Films by Magnetron Reactive Co-Sputtering C.K. Chung, T.S. Chen, C.C. Peng, B.H. Wu, C.W. Lai (National Cheng Kung University, Taiwan) The crystalline structure, composition, electrical and photoluminescent properties of Ta-Si-N thin films formed by magnetron reactive co-sputtering were investigated. X-ray diffraction (XRD) reveals that the nanocrystalline grain embedded in an amorphous matrix called amorphous-like microstructure when the Si/ (Si+ Ta) ratio is more than 9 %, whereas others are polycrystalline structures. The polycrystalline Ta-Si-N film has clear boundary and roughness surface morphology than that of the amorphous-like film with close boundary arrangement. The amorphous-like films exhibited small resistivity between 220 and 540 microΩ-cm in the range of conductor properties when the Si/ (Si+ Ta) ratio is more than 9 % and N composition is less than 50 %. In contrast, the polycrystalline films are very high between 7700 and 43000 microΩ-cm in the range of semi-conductor behavior. The photoluminescent spectrum of amorphous-like Ta-Si-N films exhibits two luminescence bands, namely a broad PL peak located at about 2.24 eV (554 nm) and about 1.90 eV (650 nm). No PL intensity was found in the polycrystalline Ta-Si-N films. The resistivity and photoluminescent properties of the Ta-Si-N films can be controlled by varying the Si and N composition.
BP-39 Thermal Stability of (Ti,Cr,Al)N/(Al,Si)N Nano-Multilayered Films Deposited by Cathodic Arc Ion Plating System N. Fukumoto (Keio University Japan); H. Ezura, K. Ichijo (Keio University, Japan); K. Yamamoto (Kobe Steel Ltd., Japan); A. Hotta, T. Suzuki (Keio University, Japan) In the field of cutting tools, the method of nano-multilayer has been paid attention to improved mechanical and chemical properties compared to conventional mono-layer films. In this report, (Ti,Cr,Al)N/(Al,Si)N films were synthesized and coating properties were analyzed mainly focusing on the thermal stability. The nano-multilayered (Ti,Cr,Al)N/(Al,Si)N films were deposited by a cathodic arc ion plating system equipped with two plasma enhanced arc cathodes manufactured by Kobe Steel Ltd. Bi-layer thickness was controlled by changing the substrate rotation speed from 1.5 to 10 rpm, resulting bi-layer thickness of 20 to 200 nm. After annealing for 2 hours in a vacuum, the films were characterized by microhardness measurement (nano-indentation), thin film X-ray diffraction (XRD) method, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to observe micro-structural changes. XRD results show that as-deposited films change their structures from cubic(c)-(Ti,Cr,Al)N and hexagonal(h)-(Al,Si)N at the substrate rotation speed of 1.5 rpm to c-(Ti,Cr,Al)N and mixed structure of h+c-(Al,Si)N at 10 rpm. As for the annealed films of 1.5 rpm, the c-(Al,Si)N (200) peak shifts from 43.260° to 43.630° at 800°C then to lower angle 42.980°, at 1100°C. In 10 rpm films the c-(Al,Si)N (200) peak also shifts from 43.040° to 43.590° at 800°C and shifts to a lower angle of 43.220° at 1100°C. However, the shift change for the 10 rpm film does not have a extensive shift as the 1.5 rpm.
BP-40 Effect of Lamellae Thickness on Characteristics and Performance of TiSiN/TiAlN Multilayers Coating Synthesized by Cathodic Arc Plasma Evaporation C.-L. Chang, W.-C. Chen, W.-Y. Ho, D-Y. Wang (Mingdao University, Taiwan) Nano-multilayer TiSiN/TiAlN films have been deposited on WC-Co substrates using TiSi (80:20 at.%) and TiAl (50:50 at.%) alloy target by a dual cathodic arc plasma evaporation system. The influences of lamellae thickness on the microstructure, mechanical, tribological, 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, residual stress and lamellae thickness. Nano-indentation and tribometer tester were used to measure the mechanical and tribological properties of nano-multilayer TiSiN/TiAlN thin films. The results showed that the hardness of the films ranged from 24-27 GPa, which the value is lower than both of TiAlN (29 GPa) and TiSiN (35 GPa). The coefficient of steady-state friction of the films against Cr steel ball ranged from 0.45 to 0.6, and TiSiN and TiAlN is 0.6 and 0.7, respectively. It has been found that the microstructure, mechanical, tribological, and corrosion properties of the films were dependent on lamellae thickness in film structure, resulting from improved mechanical, tribological, and corrosion properties of nano-multilayer TiSiN/TiAlN coatings.
BP-45 LARC and CERC Nanocomposite Coatings for High-Performance Metal Cutting Applications O. Coddet, M. Morstein, A Luemkemann, T. Cselle (Platit AG, Switzerland); B. Torp (Platit Scandinavia, Denmark) Platit LARC^(R) and CERC^(R) technologies have been successfully optimized for more than five years and provide today a unique and flexible means of depositing Ti and Cr-based nanocomposite coatings. Unmatched performance is achieved with these high-tech industrial coatings especially in difficult-to-cut materials. Both nACo^(R) (Ti_1-xAl_xN/Si₃N₄) and its Cr-based equivalent, nACRo^(R) (Cr_1-xAl_xN/Si₃N₄) have proven over the years their stability at high temperatures with the Si addition and their reliability in highly alloyed materials machining. Depending on the application, coating properties, structure and composition can easily be tuned and dedicated with flexible and user-friendly compact PVD platforms. A further emphasis will be on the presentation of coatings performance for various demanding operations. First, reaming in high-chromium steel has shown a strong improvement by using nACRo^(R) coating. The help of a carbon toplayer in austenitic stainless steel tapping has revealed nACVIC^(R) as a superior candidate because of its low friction coefficient. Then aerospace Ni-based alloys have clearly exhibited the advantages of the whole Platit nanocomposite coating family in drilling. The results will be related to the coating characteristics.
BP-47 Evaluation of the Effect of TiN and ZrN Coating on the Corrosion Resistance of the Aluminium 7075T-6 Alloy L. Jimenez, L.E. Gil (Polytechnic Experimental National University (UNEXPO), Venezuela); M.H. Staia, E.S. Puchi-Cabrera (Universidad Central de Venezuela); E. Bourhis, D. Eyidi (Université de Poitiers, France); O.A. León (Polytechnic Experimental National University (UNEXPO), Venezuela) The aluminum alloy 7075-T6 is a structural alloy widely used for aeronautical applications due to its favorable ratio of mechanical resistance and weight. A significant advance in order to improve the corrosion resistance of this alloy is related to the application of a coating. The purpose of this work, therefore, was to investigate the effect of the application of both TiN and ZrN PVD coatings on the corrosion resistance of an aluminum 7075-T6 alloy. These coatings have been widely studied on steels substrate and the reported performance was promising. However, the corrosive behavior of the aluminum coated systems has not been sufficiently studied and the deposition of these coatings could be an interesting solution. The TiN and ZrN coatings were deposited industrially using the closed field unbalanced magnetron sputtering ion plating deposition technique. The corrosion resistance was evaluated by conducting potentiodynamic polarization curves in a 3 % NaCl solution. Both optical and scanning electron microscopy (SEM) techniques were employed for the coatings morphological characterization before and after the corrosion test. SEM coupled with energy dispersive X-ray analysis (EDS) allows to identify the possible mechanisms of corrosion. The potentiodynamic polarization measurements showed that for both coatings under study the corrosion potential (Ecorr) was shifted towards a more positive potential value, and the corrosion current density (icorr) value decreased as compared to the uncoated 7075-T6 alloy substrate. However, it was determined, that for the same conditions, the ZrN coatings has a better corrosion resistance as compared to the TiN coated system, and this behavior was attributed to the columnar structure of the later coating and the presence of a higher amount of defects produced during deposition such as pores, pinholes, cracks, which weakens the protective nature of them, since they constituted the initiation sites for corrosion process.
BP-48 Raman Spectra and Structural Analysis of TiC_xO_y Thin Films: Effect of Preparation Conditions A.C. Fernandes, C. Moura, P. Carvalho (Minho University, Portugal); Ph. Goudeau, J.P. Riviere (Université de Poitiers, France); F. Vaz (Minho University, Portugal) Recently, a new class of materials is gaining importance for multifunctional applications, the so-called metallic oxycarbides, MeC_xO_y (Me = early transition metal). This importance comes from the fact that the presence of oxygen allows the tailoring of film properties between those of "opure" metal carbides and those of the correspondent oxides. Tuning the oxide/carbide ratio allows to tune the electronic and structural properties of the as-deposited films and thus their optical, electric and mechanical properties, opening a wide range of possible applications. For this work, Raman spectroscopy will used as a local probe to characterize the structural evolution of magnetron-sputtered multifuncional titanium oxycarbide TiC_xO_y films as a result of varied ion bombardment conditions as well as continuous increase of the reactive gas flows in the working atmosphere. The lines shapes, the frequency position and widths of the Raman bands show a systematic change as a function of the reactive gas flow (oxygen). The as-deposited titanium carbide film presents a Raman spectrum with the typical broaden bands, due to the disordered induced by C vacancies. The recorded Raman spectrum of the titanium oxide film is typical of the mixed rutile and anatase phases of TiO₂, which is also revealed by the X-ray diffraction. Raman spectra of titanium oxycarbide thin films present changes, which are found to be closely related with the oxygen content in films and the consequent structural changes. Also some changes were found with the variation of the bias voltage, consistent with the X-ray diffraction characterization.
BP-49 Improvement on Corrosion Resistance of Mold Steel by (Ti,TiAl)(C,N) Filtered Arc-PVD Coatings C.-H. Hsu, Y.-F. Chen, C.-Y. Lee, C.-C. Lee (Tatung University, Taiwan) In this study, cathodic arc deposition system with filter attachment was utilized to synthesize multilayered (Ti,TiAl)(C,N) coatings on DC53 substrate for investigating the coating effect on corrosion resistance of the mold steel via polarization test in 3.5wt% NaCl solution. Coating morphology and characteristics containing roughness, hardness and adhesion were also analyzed. The results showed that the multilayered (Ti,TiAl)(C,N) coatings could be successfully deposited on DC 53 substrate. In the case of coating characteristics, the filtered coatings have a dense structure and smooth surface as compared to the unfiltered coatings. However, its deposition rate is relatively reduced, and surface hardness of filtered coated specimen is lower than that of unfiltered coated one due to its thinner coating resulting from a slower rate. In addition, both the coatings with and without filter can evidently improve corrosion resistance of DC53 steel in 3.5wt% NaCl solution.
BP-50 Mechanical Properties of Electroless Ni-P Deposited on Aluminum 7075-T6 E. Moreno, M.H. Staia, E.S. Puchi-Cabrera (Universidad Central de Venezuela); J. Lesage, G. Mesmacque (Université de Lille, France); E. Le Bourhis, Ph. Goudeau (Université de Poitiers, France); T. Dorado López, A. Gómez Coedo (CENIM - CSIC, Spain) Despite the high mechanical strength and high strength to weight ratio of aluminum alloys, their use is limited if the mechanical components based on these alloys are operating in harsh environment such as high pressure, corrosive and abrasive among others. However, in the last decades a significant increase in the application of the aluminum alloys in aerospace industry has taken place and this, in part, is due to a proper engineered surface of these alloys. Electroless deposition process is one of the methods which were able to extend the useful life of different components by increasing their wear resistance. The present work is carried out to determine the mechanical properties of the as-deposited electroless Ni-P obtained commercially on Al 7075-T6 alloy and the response to different sliding wear conditions at room temperature against a WC ball. Microstructural and morphological characterizations of the coated samples were carried out by using XRD and SEM studies, respectively. Chemical analysis of the coatings was carried out by using 2 different complementary methods such as Inductively Coupled Plasma Mass Spectroscopy (IPC) and Glow Discharge Optical Spectroscopy and an average of 10% P was determined. The as-deposited Ni-P samples were indented at room temperature by using a nanohardness tester machine. The tests were performed in air, with a maximum load which varied between 10 and 150 mN. Material properties are derived from records of the load and depth of penetration. It was found a Young modulus of 140 ±2 GPa and a hardness of 7.1±0.2 GPa. The wear tests were carried out at 2,5N, 5N and 10N loads, respectively with a sliding velocity of 0.1ms^-1. It was demonstrated that, for the higher load employed during the wear test, the wear resistance of the coated aluminum Al 7075-T6 alloy could be increased by nearly 2 orders of magnitude as compared to the uncoated alloy.
BP-52 Low-k Dielectric Organosilicate Thin Film With Nano-Pores Y.-H. Park (Research Institute of Industrial Science and Technology, Korea) The preparation of low- and ultralow-k organosilicate dielectrics thin film was made from a blend system of polymethylsilsesquioxane (PMSSQ) precursor and, as a pore generator (i.e., a porogen), modified dendrimer. Porogen was removed from film matrix by thermal decomposition and gave nano pores with <2.0 nm radius even at high loading of the porogen. This pore size is the smallest ever achieved. The k value of film is nevertheless much higher than the lowest attainable k (= 1.0), that of air (or vacuum). There has thus been much interest in incorporating air into dielectric materials, producing porous materials with low k values (≤2.5). The method presented here successfully delivers low- and ultralow-k PMSSQ dielectric thin films with very low dielectric constant ~1.7.
BP-53 Thermally Activated Superficial and Interfacial Modifications of a VC Coting Deposited by CVD on Ni Substrate L. Matamoros, I.C. Grigorescu, A. Ruiz (Universidad Simón Bolívar, Venezuela); D. Morel (HE-ARC Ingénierie, Switzerland); C. Rojas (Universidad Central de Venezuela); E. Barrios (IUTRC, Venezuela) Vanadium carbide coatings of 4-5 µm thickness were deposited on a Ni (99,99% purity) substrates by CVD process, which was performed at 1000°C according to the reaction VCl₄ --> VC+4Cl. The coated samples were heat treated in Ar atmosphere (99,99% purity) at 1150°C, during time intervals between 5 and 180 min, in order to understand the behavior of the VC-Ni interface during the sinterization of Ni cemented carbide. Cross sections of the coating-substrate system were metallogrpahically prepared and observed in optic and scanning electron microscopes. The chemical compositions of the coatings and substrates were analyzed by X-ray diffraction (XRD), energy dispersive X ray spectroscopy (EDS) and scanning Auger electron microscopy (SAM). During the CVD process, important amounts of V, C and Ni diffused trough the interface. Ni diffused into the coating up to 20 at % while V and C diffused into the Ni substrate, forming solid solution layer as well as Ni-V (Ni₂V and /or Ni₃V) intermetallic precipitates. The thickness of the modified layer is of about 15µm. Despite the cautions that were taken to avoid sample contact with air, during both ambient and high temperature exposure, surface oxidation was observed in all samples. However, oxygen could be substantially removed by argon etching, previous to SAM analysis, therefore reliable information of phases chemistry was acquired. As the result of the later heat treatment, the thickness of the modified inner layer increased to about 30 µm when the time exposure to high temperature was of 180 min. In this layer, the amount of Ni-V intermetallic precipitates increases and small V₈C₇ particles form. Thereafter, intermetallic and carbides precipitates grow. Also, when time increases, the Ni-V solution extends into the depth of the substrate.
BP-54 Development of Zirconium Modified Aluminide Coating by CVD in Fluidized Bed Reactor L. Sánchez, F.J. Bolívar, M.P. Hierro, J.A. Trilleros, F.J. Pérez (Universidad Complutense de Madrid, Spain) In this work, a zirconium modified aluminium coating was obtained by use of chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic steel. The zirconium was introduced together with the aluminum in the reactive part of the fluidized bed This process originates an iron-aluminide intermetallic diffusion coating dense, continuous, and thicker than the coating obtained without zirconium addition. Firstly, a thermodynamic study of partial pressures of aluminium and zirconium halides present in the system during the deposition process was previously studied using Thermo Calc computational code, and the chemical reactions that originate the gaseous precursors were also studied. In order to optimize the experimental conditions that can originate the best Zr modified coating, parameters such as temperature of deposition, amount of zirconium introduced into the reactive bed, were evaluated and compared with results obtained for simple aluminium deposition by CVD-FBR. Results were analyzed by means of X ray- diffraction (XRD), optical microscopy (OM), Scanning electron microscopy (SEM) and Energy Dispersion Spectroscopy (EDX).
BP-55 Evaluation of the Effect of Heat Treatment in Aluminium-Hafmium Coating Deposited on Ferritic Steels by CVD-FBR Technology F.J. Bolívar, L. Sánchez, M.P. Hierro, J.A. Trilleros, F.J. Pérez (Universidad Complutense de Madrid, Spain) The depositions Al-Hf coatings on 9-12% by CVD-FBR were studied. Aluminium diffusion coatings were obtained on ferritic steels HCM-12A. The effect of heat treatment under inert atmosphere was also been studied. Diffusion heat treatment was performed at 700°C for 4 hours in order to allow the phases transformation of FeAl₃ and Fe₂Al₅ to phases with lower aluminium content. Morphology and composition of the coatings were characterized by different techniques, such as scanning electron microscopy (SEM), electron probe microanalysis, and X-ray diffraction (XRD). The results are discussed in relation to the diffusion occurring during the heat treatment of Al-Hf coatings obtained at low deposition temperatures and short deposition times. Also, have been evaluated the cyclic oxidation behaviour of Al-Hf coatings in air at 650°C .
BP-56 The Influence of the Mechanical Properties of PVD Coated Cutting Tools on Milling and Turning Performance K.-D. Bouzakis, J. Anastopoulos, N. Michailidis (Aristoteles University of Thessaloniki, Greece) The cutting performance of tools coated with (Ti,Al)N and TiCN PVD films of various compositions, thickness, structures and mechanical properties, was investigated in turning and milling. The mechanical properties, in terms of stress-strain curves, of the substrate and of the coatings were established by nanoindentations and results' evaluation through appropriate FEM-based algorithms. Furthermore, perpendicular and inclined impact tests were conducted to characterize the films' fatigue and adhesion, as well as to determine the coatings' fatigue endurance stress and fracture ratio after certain number of impacts at the same load. The tool wear development was monitored by optical and SEM investigations as well as EDX analyses. Based on the experimental turning and milling results and employing a developed FEM simulation model, which allows the determination of the stress field in the cutting wedge region, the wear initiation and propagation for all the investigated coated tools were explained. The obtained results revealed a good correlation between the coatings' mechanical properties, i.e. the Young's modulus, yield strength, fatigue endurance stress and fracture ratio after certain number of impacts at the same load, with their wear behavior, i.e. number of cuts in milling and the removed chip length in turning.
BP-57 Production and Characterization of (Ti,Mg)N Nano-Composite Coatings K. Kazmanli, B.S. Demirel (Istanbul Technical University, Turkey) Because TiN coating has a good bio-compatibility in blood and bone, it has been found applications on medical implants such as hip joints in order to improve wear and fatigue resistance of the implants. On the other hand, recent researches revealed that Mg has an important role on bone tissue growth. Incorporation of Mg into TiN coatings can improve bio-activity and compatibility of the coatings. Furthermore, a nano composite (Ti,Mg)N coating can also provide a fine grained bone growth on the coating surface. Aim of this study is to produce Mg added TiN nano composite coatings by using ion beam assisted dual magnetron sputtering deposition technique. Mg contents were adjusted by changing sputtering periods of the symmetrical bipolar pulse power supply. On the other hand, energy of the ion beam was also changed in order to see its effect on the nano composite structure formation. Mg contents of the coatings changed between 2.72 and 41.61 at.% depending on the sputtering periods. The coatings were characterized using Energy Dispersive X-Ray Spectroscopy and X-Ray Diffraction (XRD) techniques. Cross sectional morphology of the coatings was observed by Field Emission Gun Scanning Electron Microscope. On the other hand, crystallite sizes of the coatings were calculated from XRD patterns of the coatings by means of Williamson-Hall method and compared with the results of the cross section observations.
BP-59 Mechanical and Tribological Properties of Hard SiCN Coatings Produced by PECVD V.I. Ivashchenko, L.A. Ivashchenko, M.V. Ushakov, S.M. Dub, A.V. Vasin, P.L. Skrynsky (NAS of Ukraine) Silicon carbon nitride (SiCN) coatings were prepared by the plasma enhanced chemical vapor deposition (PECVD) using methyltrichlorosilane (MTCS), nitrogen and hydrogen as precursors at various nitrogen flow rates (F_N). Since MTCS is rarely used for producing PECVD SiCN coatings, an accent was put on the detail characterization of these coatings. The coatings deposited on silicon substrates were characterized basing on AFM, XRD, FTIR analyses and nanoindentation, calowear and scratch tests. X-ray diffraction indicates that the coatings prepared at moderate F_N are nanostructured and represent the α-Si₃N₄ crystallites embedded into the a-SiCNO:H matrix. The coatings deposited at another conditions are amorphous. The formation of the nanostructure is supposed to cause an increase in the nanohardness and Young's modulus above 25 and 200 GPa, respectively. The tribological tests carried out by using the Berkovich diamond indenter revealed that the friction coefficients of these coatings are 2-3 times smaller compared to those of the coatings deposited under another conditions. It follows from the ball-on-plane (calowear) tests that the nanostructured coatings exhibit also highest abrasive wear resistances. These findings point to that the SiCN coatings that exhibit good mechanical and tribological properties can be successfully deposited using MTCS as the main source material.
BP-60 Deposition of SiOCN and Si-C:H Films in an Industrial Pulsed dc PACVD System C. Forsich, D. Heim (University of Applied Sciences Weis, Austria); T. Mueller (Rubig GmbH&CoKG Weis, Austria) SiOCN as well as amorphous carbon-silicon (Si-C:H) coatings offer a combination of low friction coefficient under unlubricated conditions, low surface energy and high wear resistance. Therefore they are very useful engineering coatings in a wide range of tribological applications. A common method to deposit such coatings is plasma assisted chemical vapor deposition (PACVD) by the use of radio frequency (e.g. 13.56 MHz) plasmas. Pulsed dc-plasmas are commonly used for thermochemical heat treatments such as plasma nitriding. The advantages of using pulsed dc plasmas are that there is no need for an impedance matching, no self biasing and the possibility to upscale such system to dimension up to several meters. By adding Si-precurser supplies such systems can be used to perform duplex treatments with SiOCN or Si-C:H coatings as top layers. This paper reports on the deposition of SiOCN and Si-C:H coating by bipolar pulsed dc PACVD process in a commercially available plasma nitriding and PACVD system on different steel substrates. Further, a unipolar pulse mode deposition process was successfully performed in order to avoid undesirable deposition on an insulation coating on the counter electrode (chamber wall), leading to a time consuming cleaning of the reactor. The obtained coatings were characterized by the means of several analytical methods namely SEM(scanning electron microsopy), XRD (X-ray diffraction), GDOES (glow discharge optical emission spectroscopy). Mechanical properties like hardness and adhesion of the resulting films are measured by nano-identation and scratch tests. The surface energy of the different coatings is determined and the increase of corrosion resistance is tested by salt spray test.

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