ICMCTF2009 Session FP: Symposium F Poster Session
Thursday, April 30, 2009 5:00 PM in Room Town & Country
Thursday Afternoon
Time Period ThP Sessions | Topic F Sessions | Time Periods | Topics | ICMCTF2009 Schedule
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FP-1 DC Electric Field Induced Second Harmonic Generation Studies of Low Dielectric Constant SiOC(-H) Thin Films
R. Navamathavan (Chonbuk National University, Korea); C. Y. Kim, H. S. Lee, J.-K. Woo, C.K. Choi (Cheju National University, Korea); S.H. Seo, H.Y. Chang (Korea Advanced Institute of Science and Technology, Korea) Second harmonic generation (SHG) optical techniques have been utilized to investigate charge carrier dynamics associated with surfaces and interfaces of semiconductor/dielectric structures as a noninvasive and reliable probe method. The performance and reliability of metal-insulator-semiconductor (MIS) structures depends more and more on the microscopic quality of the dielectrics and their interfaces. In this study, the Al/SiOC(-H)/p-Si(100)/Al interface is probed by the interferometry of direct current (dc) electric field induced second harmonic (EFISH) generation. Carbon doped silicon oxide (SiOCH) film with low dielectric constant are deposited on p-type Si(100) substrates by using plasma enhanced chemical vapor deposition (PECVD) technique. The SiOC(-H) films with different precursor flow rate of ratios varying from 40 to 100 % are deposited. The output of a Q-switched Nd:YAG laser at 1064 nm with a pulse duration of 8 ns, maximum average power of 9 W and energy of approximately 5 mJ/pulse is used as the fundamental radiation. The incoming linearly polarized light is directed onto the Al/SiOC(-H)/p-Si(100)/Al samples at a 45° incident angle and focused to 750 μm diameter spot on the sample. The SHG signal are selected by a polarization analyzer and detected in the photomultiplier tube. The interface state density of the as-deposited Al/SiOC(-H)/p-Si(100)/Al structure prepared with the flow rate ratio of 90% was considerably lower than with the flow rate ratio of 60%. |
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FP-2 Light Out-Coupling Properties of Organic Light-Emitting Diodes with the Ba-doped Alq3 Layer and Degradation Mechanism of the Devices Based on its Electronic Structure
J.T. Lim, G.Y. Yeom (Sungkyunkwan University, Taiwan) The Ba-doped Alq3 layer into the organic light-emitting diodes (OLED) was inserted both to reduce barrier height for an electron injection and to improve the electron mobility, from cathode to the electro-transporting layer of tris(8-quinolinolato)aluminum (III) (Alq3). The light out-coupling property of the OLEDs, which is consisted of glass / ITO / 4,4’,4”-tris[2-naphthylphenyl-1-phenylamino]triphenylamine (2-TNATA, 30 nm) / 4,4’-bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (NPB, 18 nm) / Alq3 (42 nm)/ Ba-doped Alq3 (20 nm, x %:x= 0, 25, and 75) / Al (20 nm), was investigated. The OLED with the Ba-doped Alq3 layer of 25% showed the highest light out-coupling characteristic as the luminance of about 61000 cd/m2. This device performance could be interpreted on the base of chemical reaction between Ba and Alq3 as well as electron injection property by analyzing electronic structure of the Ba-doped Alq3 layer. In ultra violet photoemission spectroscopy, when a doping concentration of Ba was increased from 0 to 75 %, the barrier height for electron injection was decreased in the Ba-doped Alq3 layer. Meanwhile, in O 1s X-ray photoemission spectroscopy, the Alq3 radical anion species was formed when Alq3 is doped with Ba of 25 %. However, In the case of Alq3 doped with Ba of 75%, Alq3 molecules were severely decomposed. When a doping concentration of Ba is changed, the light-emitting characteristics of the devices were well coincided with formation mechanism of Alq3 radical anion species and Alq3 decomposition species, being originated from chemical reaction between Ba and Alq3. Near-edge X-ray absorption fine structure (NEXAFS) spectra at N K-edge showed that electron charge injection could be improved by Ba than a low work function metal such as Cs, because Ba than Cs could provide more electron to the orbitals involved with the pyridyl ring co mposing the Alq3 molecule. Therefore, Ba on the Alq3 is estimated to show more excellent device performance than that of Cs. |
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FP-3 Effect of P Additions on the Thermal Stability and Electrical Characteristics of NiSi
H.-F. Hsu, C.-L. Tsai, H.-Y. Chan, T.-H. Chen (National Chung Hsing University, Taiwan) The P-inserted Ni films were fabricated by immersion deposition process on Si(100), and then the NiSi films were formed by annealing in furnace. High sheet resistance of the as-deposited Ni(P) thin film was caused by the presence of high-density and P-insert of grain boundaries. The sheet resistance reduced to low level after annealing at 4000C because polycrystalline NiSi film with Ni2P capping layer was formed. The addition of P can enhance the thermal stability of NiSi films, which was exhibited by X-ray diffraction data and sheet resistance measurement. The transformation temperature of NiSi to NiSi2 increased from 800 (for pure Ni films) to 900 0C because the P-substituted layer on the top of the NiSi film was formed when sample annealed at 500 to 800 0C. The presence of the P-substituted layer on the top of the NiSi layer can decrease the Gibbs free energy and alter the kinetics of the free-surface-related relaxation mechanism of the NiSi film, which affects the nucleation of the NiSi to NiSi2 transformation. |
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FP-4 Performance of Various Duplex Systems Based on DLC and Salt Bath Nitriding Processes of 316L Stainless Steel
L. Gil, S. Liscano (UNEXPO, Venezuela); C. Gruescu, D. Chicot (University of Science and Technology of Lille, France); E.S. Puchi-Cabrera, M.H. Staia (Universidad Central de Venezuela) The present investigation was carried out to study the potential use of the cyanide–cyanate salt bath of a 316L stainless steel as an alternative nitriding process able to provide a higher load-carrying capacity for DLC magnetron sputtered thin coatings used as biomaterial. Despite its low cost, the salt bath has not been used as a valid nitriding process for this kind of steel due to its traditional drawbacks, such as poor control of the process, which leads to the formation of a porous compound layer and, hence, to a bad corrosion and tribological performance. However, a careful characterization of the nitrided layer obtained from this process by means of Vickers indentation, which leads to the determination of the relationships between the nitrogen profile and hardness, could be used to obtain an adequate preparation of the nitrided substrate before PVD deposition, by carrying out the right elimination of the compound layer. Finally, the nitrided substrates produce d in different conditions were characterized by employing standard corrosion and tribological tests and a comparison was made in order to obtain the most functional substrate prior PVD deposition. |
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FP-6 Microstructure and Nanostructure of PVD ZrN-Cu Thin Films
M. Audronis, O. Jimenez, A. Leyland, A. Matthews (The University of Sheffield, United Kingdom); C. Tsotsos (University of Cyrpus) ZrN-Cu films containing variable amounts of copper, namely 8, 33 and 58 at. %, were produced by reactive pulsed unbalanced magnetron sputter deposition. Coatings were found to possess hardness values of 22.5, 9.5 and 3.7 GPa, respectively. The morphology of coatings was investigated by field emission scanning electron microscopy and the microstructure and nanostructure were investigated by conventional (bright-field and dark-field imaging) and high resolution transmission electron microscopy. Complementary X-ray diffraction experiments were also performed. ZrN coatings containing 8 at. % of copper were found to possess a nano-columnar structure composed of ZrN columnar grains, the diameter of which was approximately 15 to 30 nm. The majority of the copper content was apparently dissolved within the ZrN grains, rather than existing as a separate phase. Coatings of the two other compositions were found to be composed of a mixture of mostly equiaxed ZrN and Cu grains, the diameters of which were in the approximate range of 10 to 30 nm. None of the coatings investigated in this study were found to possess the so-called ‘nanocomposite’ structure, which is often pictured as crystalline grains surrounded by an amorphous phase. Instead, coatings were found to be either single-phase ZrN with Cu in substitutional solid solution for Zr or a mixture of ZrN and Cu nano grains. |
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FP-7 Bias Efects on the Wear Behavior of AISI 304 Stainless Steel Arc-Deposited CrTiAlN Multilayer Coatings
C.-H. Hsu, K.-L. Chen, Z.H. Lin (Tatung University, Taiwan); C.-K. Lin (Feng Chia University, Taiwan) In this study, CrTiAlN multilayer coatings were deposited on AISI 304 stainless steel using a cathodic arc deposition system controlled at the different biases. Coating morphology and properties such as coating structure, adhesion, hardness/elastic modulus (H/E) ratio, and abrasion behaviors were analyzed to evaluate the bias effects on the coatings for application on AISI 304 stainless steel. The results showed that when bias value was controlled at -150V, not only Cr content in the coatings had an increase, but also the better properties such as lower Ra value, HF1 adhesion strength, and higher H/E ratio were all obtained. Sequentially, the coated specimen produced with the bias value of -150V showed an outstanding wear resistance as compared to the uncoated and the other coated ones. |
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FP-8 Microstructure Analysis of TiO2 Thin Film Modified by Metal Plasma Ion Implantation for Enhanced Photosensitivity
D.-Y. Wang (Mingdao University, Taiwan); C.-C. Yen (National Chung Hsing University, Taiwan); M.-H. Shih (Mingdao University, Taiwan); L.S. Chang, H.-C. Shih (National Chung Hsing University, Taiwan) Photo-catalytic TiO2 thin films were prepared by using sol-gel process. To improve the photo-sensitivity of TiO2 at visible light regime, transition metals of Cu, Fe, and Ni were implanted into the TiO2 matrix at 30 KeV by using the metal plasma ion implantation (MPII) process. The additional band gap energy levels created due to the formation of the implanted metal oxides extended the photosensitivity range of the anatase TiO2 to cover the visible light spectra, allowing increased photo-catalytic efficiency of TiO2. Pure anatase TiO2 thin films posses a transparency better than 80% transmittance between 450 and 800 nm. The irradiation of the medium-energy metal plasma posed significant effects on the lattice distortion as well as the microstructure of TiO2 thin films. The loss of transmittance of the metal-implanted TiO2 was resulted from the formation of the photo-catalysis adsorption in addition to the existence of typi cal adsorption centers such as lattice defects, structural defects, composition fluctuation, impurity compounds, and others. In this study, the implantation parameters were optimized to compensate the loss of TiO2 transparency without significantly affecting the formation mechanism of impurity oxides. The microstructure and morphological analyses will be conducted by using electron microscopy, photo-luminance spectroscopy, and atomic force microscopy. |
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FP-9 Analysis of ZrN/Zr Thin Film on Flexible Polyethylene Terephthalate (PET) Substrate Deposited by Unbalanced Magnetron Sputtering
H.-M. Chu, J.H. Huang, G.P. Yu (National Tsing Hua University, Taiwan) Recently, polymer-based organ light-emitting diode (OLED) was developed due to the issues of energy and environment. However, the gas impermeability of polymer substrates is very bad. The permeation of water and oxygen vapor can oxidize the cathode of OLED, which seriously decreases its performance and lifetime. To reach the requirement of OLED (water vapor transmission rate, WVTR, <10-6 g/m2/day; oxygen transmission rate, OTR, <10-3 cm3/m2/day), several barrier coatings like silicon oxide and nitride have been developed. In this study, ZrN was chosen to deposit on flexible polyethylene terephthalate (PET) substrates by unbalanced magnetron sputtering system (UBMS). According to the literatures, the interlayer between the thin film and substrate can improve the adhesion and relax the residual stress. Besides, the pure Zr interlayer can increase the electric conductivity and the packing density of the thin film. The effect of diffe rent deposition time of ZrN and Zr was investigated in terms of adhesion, electrical resistivity, surface roughness, transmittance and WVTR. Scanning Electron Microscopy (SEM) was used to observe micro-structure. The crystal structure was characterized by Glancing Incident X-ray Diffraction (GIXRD). Compositions of the thin film were measured by Rutherford Backscattering Spectroscopy (RBS) and X-ray Photoelectron Spectroscopy (XPS), and the packing factor can be calculated by the results of RBS. The composition depth profile was analyzed by Auger electron spectrometer (AES). Four-Point Probe was utilized to measure the sheet resistance. The adhesion and the wettability of thin films were tested by Cross-Hatch Test and the Contact Angle System, respectively. Atomic Force Microscopy (AFM) was used to measure the surface roughness. Transmittance of the thin film was determined by UV-Visible Spectrophotometer. Besides, the color and the reflectance of the thin film were analyzed by HunterLab MiniScan XE Plus Spectrophotometer Model 4000VSAV. Finally, Water Vapor Permeation Instrument was used to measure the WVTR. The transmittance decreased with increasing film thickness. The WVTR was obviously affected by film thickness and packing factor. Films with higher packing factor and thickness had better gas impermeability. The sheet resistance was decreased with increasing thickness of Zr interlayer. Further correlations between structure and properties are described in this paper. |
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FP-10 Dynamic Deformation and Durability Evaluation of Various Lubricant Coated Magnetic Disks
W. Kurosaka, K. Oshimoto, S. Miyake (Nippon Institute of Technology, Japan) Nanowear and viscoelastic evaluation tests were performed to study the nanotribological properties of various perfluoropolyether lubricant (thick-Ztetraol, thin-Ztetraol, D-Tetra and A20H-DD) films coated magnetic disks. The magnetic-disk surface protrudes due to friction, partially. This result corresponds to the result of viscoelastic change by nanosliding evaluated by AFM(atomic force microscopy). In the case of A20H-DD and thick Ztetraol, tanδincreases by friction. This shows the increase of lubricant by sliding. On the other hand, in the case of D-Tetra, tanδ decreases by sliding. Tan δ of the protuberance area is the smallest. This result shows the similar tendency of the case that the magnetic disks without lubricant. The friction properties of the various lubricant coated magnetic disks are evaluated by the reciprocating friction tests. The friction coefficients of A20H-DD coated magnetic disks are stable, and friction damages are also less than the others. T hese superior properties of A20H-DD coated magnetic disk correspond to nanotribological results evaluated by AFM. |
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FP-11 Interface Evolution of Annealed SiO2 and Ta/SiO2 Encapsulated Cu Films
A.P. Warren, T. Sun (University of Central Florida); K. Barmak (Carnegie Mellon University); M.F. Toney (Stanford Synchrotron Radiation Laboratory); K.R. Coffey (University of Central Florida) Surface roughness induced scattering has been considered as a potential contributor to high resistivity in Cu interconnects. To study the evolution of roughness with annealing, a series of Cu thin films ranging in thickness from 28 nm to 158 nm, encapsulated in SiO2 and Ta/SiO2 were fabricated. The samples were annealed at 150°C and 600°C following deposition. The root mean square interfacial roughness was characterized by specular x-ray reflectivity for both the upper and lower Cu interfaces. The lateral correlation length of the roughness was studied by diffuse x-ray reflectivity and grazing incidence small angle x-ray scattering. The measured interfacial roughness was in the range of 2 Å to 15 Å. Little correlation was observed between roughness and thickness for the samples. The roughness of the lower SiO2/Cu interface did not change with annealing temperature. By contrast, the roughness of the upper Cu/SiO2 interface decr eased by 60% upon annealing at 600°C. Such a reduction in roughness with annealing temperature was not observed in the SiO2/Ta/Cu/Ta/SiO2 samples. The lateral correlation length scaled with thickness for all samples, and annealing at 600°C resulted in longer wavelengths. |
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FP-14 Control of Hard Protective ZrN Coatings by Modulated IR Radiometry
J. Gibkes (Ruhr-University Bochum, Germany); F. Vaz, A.C. Fernandes, F. Macedo (Minho University, Portugal); K. Puchong, J. Pelzl, B.K. Bein (Ruhr-University Bochum, Germany) In the last three decades, transition metal nitrides (MeN), deposited by vapour deposition techniques, have been implemented as hard coatings on industrial devices and components to increase their lifetime and performance, mainly due to such properties as high hardness, good wear resistance, and chemical stability. In cutting, casting or hot forming, these coatings are submitted to high temperatures giving rise to microstructural changes affecting application-oriented properties. Thus, detailed knowledge about thermal properties and behavior under transient heat loads is fundamental for the successful application of such coatings. Based on Modulated IR Radiometry (MIRR), a non-destructive thermal wave technique appropriate for remote detection in industrial applications1, and based on an analytical inverse solution of the two-layer thermal wave problem2, hard protective magnetron sputtered ZrN thin films and coatings have been analyzed with respect to their therma l effusivity, the relevant parameter for time-dependent surface heating processes. For a second objective of this work, namely to control the film thickness by means of the MIRR technique, a set of ZrN films has been prepared keeping constant the deposition parameters, except the deposition time, in order to obtain films of approximately equal composition, structure, and thermal effusivity, but different film thickness. The results obtained by MIRR have been compared with the coating thickness determined by destructive measurements and confirm the reliability of MIRR for this kind of applications on ZrN films and coatings above 1 micrometer. 1 F. Macedo, A. Gören, A. C. Fernandes, F. Vaz, J. Gibkes, K. H. Junge, J. L. Nzodoum-Fotsing, B. K. Bein, Potential of Modulated IR radiometry for the On-Line Control of Coatings, Plasma Proc. Polym., 4, (2007) S857-64. |