Papers

ICMCTF1999 Session B1: Evaporation & Arc Technologies

Thursday, April 15, 1999 1:30 PM in Room Golden West

Thursday Afternoon

Start	Invited?	Item
1:30 PM		B1-1 Carbon Thin Films with Enhanced Properties from Cathodic Arc Plasmas M. Chhowalla (Multi-Arc Inc.) The physical, optical and electronic properties of amorphous carbon (a-C) thin films deposited using filtered and unfiltered cathodic arcs have been investigated. Firstly, the plasma properties of the filtered cathodic vacuum arc (FCVA) examined using planar and wire Langmuir probes will be discussed. The plasma characteristics of the FCVA will then be examined in terms of optimizing the deposition of highly tetrahedral amorphous carbon (ta-C). The variation of ta-C film properties as a function of the ion energy, temperature and deposition rate will also be reported. A model based on the intrinsic thermal effects of the deposition process will be developed to explain the discrepancy of the sp³ fraction versus the ion energy found in the literature. The possibility of p-type electronic doping of ta-C will be reported via incoporation of B. Details of a large decrease in the compressive stress of ta-C:B will also be discussed. The details of a different form of discharge (referred to as the 'stationary arc' which allows the deposition of smooth ta-C film without a bulky macroparticle filter will also be reported. Finally, the generation carbon nanoparticles using a localized high pressure discharge will be discussed.
2:30 PM		B1-4 Vacuum Arc Deposition of TiN, NbN and TiN/NbN Multi-Layer Coatings V.N. Zhitomirsky (Tel-Aviv University, Israel); I. Grimberg (Technion - Israel Institute of Technology, Israel); L. Rapoport (Center for Technological Education, Israel); N.A. Travitzky, R.L. Boxman, S. Goldsmith (Tel-Aviv University, Israel); B.Z. Weiss (Technion - Israel Institute of Technology, Israel) Single layer coatings of TiN, NbN and multi-layer coatings of TiN/NbN were deposited onto WC-Co substrate using a triple-cathode vacuum arc plasma gun connected to a magnetized straight plasma duct. The single-layer coatings were produced by depositing Ti or Nb plasmas in background of nitrogen at pressure in the range of 0.67 to 2.67 Pa. Multi-layer coatings with 20, 50 and 100 layers were deposited by alternately switching the arcs on Ti and Nb cathodes. In some cases additional magnetic fields were applied by two coils (labeled steering coils) positioned normal to the duct axis. The magnetic field produced by the steering coils directed and focused the plasma beam on a substrate placed on the system axis. The plasma flux to the sample increased when the steering coils were switched on. Coating composition and structure, and interfaces morphology were studied by means of SEM, XRD, and AES diagnostics. Coating microhardness and adhesion to the substrate were studied by Vickers micro-indentation and scratch tests, respectively. The phase composition of single Nb-N layers depended on the nitrogen pressure. When the steering coils were switched off the Nb-N layer was composed of a mixture of two phases - hexagonal and cubic - at pressures below 0.67 Pa, becoming cubic NbN at pressures P>0.67 Pa. The two-phase coatings possessed low critical load (10-30 N), whereas the highest critical load (95 N) was measured on cubic NbN deposited at P=0.93 Pa. When the steering coils were switched on, two-phase structure was observed at P=0.67-1.33 Pa, and the coatings were brittle, and only the single cubic NbN phase was obtained at P≥2 Pa. The phase composition of TiN was not affected by the application of the steering coils. Microhardness of NbN coating was 38 GPa, being much higher than that of TiN coatings (22-26 GPa). In multi-layer coatings, the interfaces between the TiN and NbN layers and between the first layer and the substrate were well defined, without intermixing. The effect of nitrogen background pressure on the structure and microhardness of the multi-layer coatings, as well as the effect of the number of the layers and their thickness on the tribological properties, will be presented and discussed.
2:50 PM		B1-5 Linear Magnetron Arc Cathode and Macroparticle Filter R.P. Welty (Vapor Technologies, Inc.) Extended deposition sources are useful for large area coating and high volume production. We have developed a new type of linear magnetron arc evaporation cathode and macroparticle filter. The cathode is a rectangular bar, with evaporation occurring around its periphery (i.e. along 2 opposite long sides and across both ends). Two oppositely-directed material streams are thereby generated, which may be extended indefinitely in length (end losses are small for long cathodes). We have also developed a macroparticle filter for this cathode that provides relatively efficient transmission of the ionized output fraction to the substrate region. Deposition characterization data for the source and filter are presented, as well as magnetic modeling results. The cathode is suitable for use as an axial source in batch systems, and permits a dual substrate stream in linear throughput systems.
3:10 PM		B1-6 Influence of an Electrical Field on the Macroparticle Size Distribution in a Vacuum Arc R. Aharonov (Multi-Arc, Inc.); M. Keidar (Cornell University) The results of experimental study of macroparticle distribution in a vacuum arc are presented for Cu, Ti, Zr and Cr cathodes. We have studied the macroparticle contamination of the films deposited on the substrate having floating potential and biased up to -1000 V with respect to the anode. It has been found that the macroparticle number significantly decreases (by a factor of 3-4) with substrate biasing for all examined cathode materials. A model of macroparticle motion in the quasi-neutral plasma and near-substrate sheath has been proposed. The model based on analyses of the macroparticle charging and motion in the quasi-neutral plasma and near substrate sheath. The model can qualitatively explain the macroparticle reduction in the coating due to negatively charged macroparticle reflection in an electric field.
4:10 PM		B1-9 A Comparison of DC and AC Arc Thin Film Deposition Techniques T.S. Schuelke (Fraunhofer USA, Resource Center Michigan); H.S. Scheibe, P. Siemroth, B. Schultrich (Fraunhofer Institute Material and Beam Technology, Germany); J.V. Vetter (Metaplas Ionon GmbH, Germany); T. Witke, O. Zimmer (Fraunhofer Institute Material and Beam Technology, Germany) DC and AC vacuum arc evaporation comprise two techniques currently implemented for Thin Film Deposition, each with specific technical aspects with regard to the discharge systems and their application fields. The DC Arc discharge at several 10-100 Å is a well established PVD Technique to deposit hard coatings for a variety of applications. Examples of applications benefiting from this technique are cutting and forming tools. The primary function of hard coatings in this instance is to reduce friction and wear, and the standard coating materials employed are TiN, CrN, TiCN and AlTiN. In contrast, Ac Arc discharges are characterized by the repetition of short current pulses up to several 1000 Å. They offer new possibilities including the increase of the average current. This is especially important for applications that require plasma filtering to reduce or even avoid droplet deposition on substrates. Yet another useful property is the increase of plasma ionization compared to DC-discharges. Applications like hard-amorphous carbon deposition and metal-interconnect deposition schemes in the semiconductor industry benefit from these superior plasma conditions. In today’s manufacturing industries, machines are designed to be fully automated to simplify the coating process which contains several steps like heating, cleaning and deposition. To increase the quality and effectiveness of the procedure itself, improvements in hardware and process developments with regard to droplet reduction and new film systems like a:C-H coatings are being explored. A further field of steadily increasing importance is decorative applications. The combination of film properties like metallic shine and scratch resistance ensures a product that is both aesthetically pleasing and functional, and offers new possibilities for the application of thin film technology.
4:30 PM		B1-10 Effect of Nitrogen Pressure and Bias Voltage on the Structure and Properties of arc PVD Molybdenum Nitride Coatings. M.K. Kazmanli, M. Urgen, A.F. Cakir (Istanbul Technical University, Turkey) In this study the effects of nitrogen pressure and bias voltage on the structure, hardness, adhesion and wear properties of Mo-N coatings are investigated. Coatings are produced at 14 mTorr, 11 mTorr, 9 mTorr, 6 mTorr and 3 mTorr nitrogen pressure by using -150V, -250V and -350V bias voltage on HSS substrates. The coating produced at nitrogen pressure of 14 mTorr with -150 V bias voltage consisted of δ MoN (hexagonal) phase and at 11 and 9 mTorr mix-phases of δ MoN and γ Mo₂N were present. At lower nitrogen pressures of 3 and 6 mTorr coatings exhibited mainly γ Mo₂N structure. Besides these two phases Mo₁₆N₇ was also present in coatings produced at low nitrogen pressures. By the increase of bias voltage it became impossible to produce single phase δ MoN even at the highest nitrogen pressure (14 mTorr) used in this study. Orientation of lattice planes showed strong dependence on the bias voltage and nitrogen pressure. Hardness of the coatings varied between 5400 and 3200 Vickers depending on the forming phases and their orientation, which are related to both bias voltage and nitrogen pressure. Adhesion and wear behavior of the coatings are also investigated.
4:50 PM		B1-11 The Investigation of Composition and Oxidation Effects on TiAlN Coating By Magnetic Filter Cathodic Arc Deposition M.-S. Leu (Industrial Technology Research Institute, Taiwan, ROC); Y.W. Lee (Industrial Technology Research Institute); W.C. Lih (Materials Research Laboratories, Taiwan, ROC) The TiAlN coatings are deposited on the stainless steel substrates by dc magnetic solenoid filtered arc method. The magnetic field intensity dependence of the variation of alumina content in TiAlN coatings is analyzed by ESCA analysis. The high temperature oxidation behavior of the TiAlN coatings can also be concerned with the alumina content by thermogravimetry analysis (TGA) measurement. Hence, the relationship among the oxidation temperature, magnetic field intensity of solenoid filter and alumina content in TiAlN coatings can be obtained by this study. Besides, the scratch test method has also used to investigate the adhesive property of TiAlN coatings corresponding to variation of the magnetic field intensity.