ICMCTF2003 Session B2: Arc and E-Beam Coatings and Technologies

Tuesday, April 29, 2003 1:30 PM in Room Golden West

Tuesday Afternoon

Time Period TuA Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2003 Schedule

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1:30 PM B2-1 Vacuum Arc Deposition by using a Venetian Blind Particle Filter
O. Zimmer, P. Siemroth (Fraunhofer Institute for Material and Beam Technology, Germany)
Vacuum arc deposition is a commonly used technology for the deposition of hard coatings and all kinds of metals. The vacuum arc discharge is a simple source of highly ionized metal plasma, but also a certain number of macro particles is emitted and deposited. That's why a great number of particle filters was developed in the past, but no one of them has larger industrial usage. A very simple but effective filter design is the venetian blind filter. The macro particles are shielded from the substrate but the plasma is guided through the filter by means of magnetic and electric fields. With this type of filter, films with a dramatically reduced number of droplets can be produced. A plasma transmission through the filter of approximately 20% could be reached. Micrographs of the film surfaces were analyzed by a certain method to investigate the droplet distribution in number and size for different materials. A filter unit for using at the most common vacuum arc deposition machines was developed and tested and is now available. The filter does not reduce the deposition area, so the standard deposition processes can be used furthermore.
1:50 PM B2-2 Cathodic Arc Evaporation of TiAlN Coatings and TiAlN/TiN Multilayer Coatings - Correlation Between Lifetime of Coated Cutting Tools, Structural and Mechanical Film Properties
F.-R. Weber (Gühring Group / G-ELIT Precision Tools GmbH, Germany)
In this work coatings of TiAlN/TiN and TiAlN have been produced by cathodic arc evaporation with large area TiAl and/or Ti arc material. The ratio of Ti/Al varies between 50/50, 40/60 and 33/67. The goal of this investigation was to study the influence of the bias voltage, which varies between - 30 and - 125 V, on the lifetime of different coated cutting tools. Parallel to the drilling tests of coated tools, film orientation, compressive stress and hardness were determined by X-ray diffraction and microindentation. The chemical composition of the coatings was investigated by Secondary-Neutral-Mass Spectrometry (SNMS). An interesting correlation between the drilling results and the film properties was found. Rockwell and Scratch tests show excellent adhesion of our coatings on carbide and steel drills, due to an improved plasma pre cleaning process.
2:10 PM B2-3 Process Optimisation of Industrial Vacuum Arc Deposition by SimCoat Simulation
B. Schultrich, S. Völlmar (Fraunhofer Institute for Material and Beam Technology Dresden, Germany)
For the deposition of protective or decorative coatings, vacuum arc has been well proved and is now widely used on an industrial scale. Vacuum arc technology is distinguished by the high degree of ionization and the high kinetic energy of the film forming particles, which allow the deposition of very hard films from conventional titanium nitride up to tetrahedral bonded carbon. Due to the directional expansion of the energetic plasma beam the coating of three-dimensional parts is only possible by the relative movement of plasma source and substrates, usually managed by rotations of the substrate holders. Hence, the deposition conditions vary periodically leading to a more or less pronounced (nano)layered film structure. The simulation program SimCoat aims to support the structural and technological optimization of the deposition process in industrial vacuum arc coaters. It is based on the kinematics of substrate and plasma source movements and on simplified but experimentally supported modelling of the film growth carefully considering the real geometrical conditions. Besides others the output parameters include film thickness and film structure (composition, density variations) in dependence e.g. on the geometry of the parts, on their position inside the chamber or on the kind of batch. The program system SimCoat has a modular structure, which allows the stepwise implementation of additional features. Input and output windows are adapted on the demands of engineers. Apart from recording the numerical data, the process and its results can be visualized to get direct insight into the interrelations between process parameters and film properties. The potential of SimCoat is demonstrated for the deposition of tetrahedral bonded carbon films by the laser controlled pulsed vacuum arc technique (Laser-Arc) in a large volume industrial coater.
2:30 PM B2-4 Change in Microstructures of Cr1-xAlxN and Zr1-xAlxN Films Synthesized by Cathodic Arc Method
H. Hasegawa, M. Kawate, T. Suzuki (Keio University, Japan)
Incorporation of Al atoms to ceramic nitride films provided higher hardness, oxidation resistance and wear resistance. It has been recognized that the Ti1-xAlxN films changes their crystal structures at the certain amount of Al into films. The Cr1-xAlxN and Zr1-xAlxN (0 < X < 1) nitride films were synthesized by the cathodic arc method using alloy and metal targets. The X-ray diffraction pattern showed that the Cr1-xAlxN changed cubic structure at X=0.6 to hexagonal structure at X=0.7. The peaks of Zr1-xAlxN showed the NaCl structure at X=0.2 and wurtzite structure at X=0.8. The scanning transmission electron microscopy (STEM) showed the grain size of Cr1-xAlxN and Zr1-xAlxN with 100-200 nm. In this study, we investigate effects of Al contents on microstructures and micro-hardness of Cr and Zr-based nitride films.
2:50 PM B2-5 Copper Film Deposition by a Hot Refractory Anode Vacuum Arc
I.I. Beilis, A. Shashurin, D. Arbilly, S. Goldsmith, R.L. Boxman (Tel-Aviv University, Israel)

The radially expanding plasma in a Hot Refractory Anode Vacuum Arc (HRAVA) was used to produce metallic coatings. The HRAVA was equipped with a conventional water-cooled metallic cathode, but the anode was made from a non-consumable refractory material. The HRAVA operated initially as a conventional vacuum arc sustained by cathode spot emitted plasma, however at a later stage, the interelectrode region also contained cathodic metal vapor re-evaporated from the hot refractory anode. The re-evaporated cathode material was strongly ionized, creating an anodic plasma without macroparticles (MP's). The HRAVA served as a plasma source with highly reduced MP contamination. In the present work the results of copper thin film deposition with the new device are described.

Arcs were sustained between the parallel end surfaces of a pair of cylindrical electrodes. A copper cathode and thermally isolated molybdenum anode were used. The lateral cathode surface was shielded. Arc currents of 150-250 A were sustained for periods of up to 80 s. The coatings were deposited on 76x26x1mm glass substrates placed at distances of 5.5-16 cm from the electrode axis along the midplane of the inter-electrode gap. In some experiments, the substrate was shielded from the plasma by a shutter, which was opened for a pre-selected time period during the arc. The film thickness was measured using a profilometer, and the coating surface was examined with an optical microscope. The MP's size distribution function was measured.

The observations showed that films with different morphologies formed on the substrate in two regions: facing the anode (anode region) and facing the cathode (cathode region), respectively. The MP content on films deposited by 30 s duration arcs on the anode region was about three orders of magnitude less than on the cathode region. The MP size distribution function in the cathode region was similar to that measured in conventional vacuum arcs. In the anode region a mirror-like film was obtained. The film thickness in the anode region increased linearly with current. The deposition rate in a 200 A arc at the distance 11 cm initially increased linearly with time and saturated after approximately 40 s. The deposition rate for 1 min duration 200 A arc at distance 9 cm was about 0.5 µm/min in the anode region and up to about 2 µm/min in the cathode region.

3:10 PM B2-6 Temporal Development of the Plasma Composition of Metal Plasma Streams in an Reactive Environment
J. Rosen (Linköping University, Sweden); A. Anders (LBNL, Berkeley); L. Hultman (Linköping University, Sweden); J.M. Schneider (RWTH-Aachen, Germany)
We describe the temporal development of the plasma composition in a pulsed plasma stream generated by cathodic arc. Cathode materials used were Zr and Cr at various nitrogen pressures. The time resolved plasma composition for the cathode materials was analysed with time-of-flight charge-to-mass spectrometry, and was found to be a strong function of the nitrogen pressure. Large plasma composition gradients were found within the first 70 microseconds of the pulse, the nitrogen concentration increasing with increasing pressure. The results are explained by the formation and erosion of a compound layer formed at the cathode surface in the presence of a reactive gas. The average charge state was also found to be affected by the reactive gas pressure as well as by the time after ignition. The charge states were highest in the beginning of the pulse at low nitrogen pressure, decreasing down to a steady state value at higher pressure. The results are of importance for reactive plasma processing and for controlling of the evolution of thin film composition and microstructure. This is obtained from an increased understanding of plasma composition and distribution of energetic species (resulting from the distribution of charge states).
3:30 PM B2-7 Effect of Underlayer on Coalescence of Silver Islands Grown by Filtered Cathodic Arc Deposition
E. Byon (Korea Institute of Machinery and Materials, South Korea); A. Anders (Lawrence Berkeley National Laboratory)

Ultrathin silver films that are not continuous show relatively high absorption in the visible and low reflection in the infrared. For low-emissivity application on window glass, coalescence of silver islands is crucial for obtaining the desired optical properties of the coating, namely high transparency in the visible and high reflectivity in the infrared. It is well known that the energy of ions arriving at the substrate and the type of underlayer affect nucleation and growth of silver islands. There are a number of studies on nucleation and growth, but little is known about coalescence of silver islands synthesized by more energetic condensation, e.g. filtered cathodic vacuum arc (FCVA). In this work, the effect of underlayer on nucleation and growth of silver films deposited by FCVA was investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results are compared with data obtained by magnetron sputtering. Eungsun Byon was supported by the Post-Doctoral Fellowship Program of the Korea Science and Engineering foundation.

This work was supported by the Office of Building Technology, U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

3:50 PM B2-8 XPS and PL Study of EB-PVD Deposited Silicon Oxynitride Thin Films
K. C. Mohite (University of Pune, India); A.B. Mandale (National Chemical Laboratory, India); B.N. Pawar (University of Pune, India); K.R. Patil (National Chemical Laboratory, India); M.G. Takwale (University of Pune, India)

Electron Beam Physical Vapor Deposited (EB-PVD) silicon oxynitride (SiOxNy) films of various compositions between SiO2 and Si3N4 were grown by changing the substrate temperature and deposition time The SiOxNy films were deposited at various temperatures ranging from 100°C to 400°C on single crystal wafer ( single side polish)and soda lime glass substrates. Films were characterized by using XPS, EDS, Photoluminescence, UV-Visible spectroscopy and Ellipsometry.

The XPS analysis show the incorporation of nitrogen in the films increases with increase in substrate temperature and deposition time.The XPS spectra of the films shows Si,N,O and carbon species on the surface. The incorporation of nitrogen in the films is further confirmed by photoluminescence spectra. The photoluminescence spectroscopy measurements were done at room temperature. The energy of the PL peak for 2.54eV (~490 nm) excitation is 2.30 eV (~560 nm).This is an interesting result since similar spectra has also been observed in porous silicon and silicon oxide implanted with silicon suggesting a likely similar cause for the photoluminescence in all these cases. The annealing effect of SiOxNy samples at 800°C on PL intensity is discussed.The ellipsometric measurements shows that the values of refractive indices , n and k are in the range of 1.60 to 1.98 and 0.03 to 0.08 respectively.

4:10 PM B2-9 Structure and Properties of Cathodic Arc Ion Plated CrN Coatings for Copper Machining Cutting Tools
A. Kondo, T. Ogami, K. Sato, Y. Tanaka (MMC Kobelco Tool Co., LTD., Japan)
Cathodic arc ion plated CrN coatings were deposited on WC-Co substrates by changing the substrate bias voltage and nitrogen partial pressure. The composition and structure of the films were investigated by electron probe microanalysis (EPMA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Single phase CrN with face centered cubic was synthesized under a wide nitrogen partial pressure of 1-13 Pa. Microstructure of CrN coatings changed by the substrate bias voltages and a dense columnar structure was developed with small negative substrate bias voltages. Microhardness of the coatings was examined by Vickers indentation and the reactivity of CrN coatings with Cu was investigated by annealing tests of Cu deposited CrN coatings. Wear resistant property and friction coefficient of CrN coatings against Cu was evaluated by ball on disc test, and the results were discussed with the film structure. Copper machining performance of CrN coated carbide endmills were also investigated and the films deposited with the low negative substrate bias of -30V showed the best cutting performance. Wear resistant properties and surface finish characteristics of the endmills will be discussed with the structure and properties of CrN coatings.
4:30 PM B2-10 Reducing the Macroparticle Content of Cathodic Arc Evaporated TiN Coatings
S.G. Harris, E.D. Doyle, Y.-C. Wong (Swinburne University of Technology, Australia); P.R. Munroe, J.M Cairney (University of New South Wales, Australia); J.M. Long (Deakin University, Australia)
Cathodic arc evaporation (CAE) is a widely used technique for generating highly ionised plasma from which hard wear-resistant PVD coatings can be deposited. A major drawback of this technique is the emission of micron-sized droplets of cathode target material from the arc spot which are commonly referred to as ‘macroparticles’. In this study, the effect of cathode target poisoning was investigated as a method to reduce the number of macroparticles in PVD coatings. While the study focuses on the reduction of macroparticles in TiN coatings, the outcomes and key findings can be broadly applied to the cathodic arc process, in particular, for the reduction of macroparticles in more advanced CAE coatings. The results support earlier findings which have shown that poisoning of the cathode target can reduce the number of macroparticles emitted from the arc spot. The results of GD-OES showed that the titanium content of the coatings varied little between the respective coatings despite changes in the deposition pressure from 0.1 to 1.2 Pa. The GD-OES results also showed the presence of oxide contamination at the surface of the coatings which was significantly reduced with increasing deposition pressure. The coatings were also deposited onto high-speed steel twist drills to compare the metal-cutting performance when dry drilling a workpiece of cast iron. The results of the drill tests showed that tool life increased with a reduction in the number of macroparticles.
Time Period TuA Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2003 Schedule