ICMCTF1999 Session B4: Emerging Technologies & Critical Issues in Vapor Deposition

Monday, April 12, 1999 8:30 AM in Room Golden West

Monday Morning

Start	Invited?	Item
10:30 AM	Invited	B4-7 Approaches to Rid Cathodic Arc Plasmas from Macro- and Nanoparticles A. Anders (Lawrence Berkeley National Laboratory) Cathodic arc plasma deposition is a technology with great potential. Most noticeable, cathodic arc plasmas are fully ionized and can therefore be manipulated with electric and magnetic fields. While electric fields allow for changes in the ion energy and thus structure and properties of the films deposited, magnetic fields are used to guide and homogenize the plasma. While (reactive) cathodic arc plasma deposition is a well-established technique for some decorative and protective film systems such as TiN, it is not (yet) widely used for other materials such as alumina, or amorphous, hydrogen-free, tetrahedrally bonded carbon ("amorphous diamond"). The major obstacle for broad application is the presence of micro- and nanoparticles in the plasma, also often referred to as "macroparticles" emphasizing their massive nature compared to ions and electrons. Over the last two decades, a number of approaches have been proposed and tested toward reduction and eventual elimination of macroparticles. The present paper reviews the generation of macroparticles at cathode spots as well as various methods of their reduction and elimination. Emphasis is given to a number of magnetic filtering methods including novel designs, the physics of plasma transport, and loss mechanism. Methods are compared and guidelines for the design of efficient deposition systems are derived. This work was supported by the US Department of Energy.
11:10 AM		B4-9 Filtered Laser-Arc: A New Technology for Deposition of Particelfree Films C.F. Meyer, H.-J. Scheibe (Fraunhofer - Institut f. Werkstoff und Strahltechnik, Germany) Vacuum arc deposition technology for film deposition is establish for industrial deposition of hard coatings as TiN, ZrN, TiAlN and especially for diamond-like carbon films. A disadvantage of these deposition method is that great particles and droplets are in deposited layers. Therefore there are many efforts to separate these particles from arc plasma. We report on a new developed filter arrangement using electric field for separation of particles from plasma of vacuum arcs, especially from plasma of laser ignited vacuum arc (Laser Arc). The advantages of these kind of filter are unlimited linear extension of deposition area, simple construction and high efficiency. The function of filter, problems and influence of different parameters how bias voltage and distance of absorber electrode from anode in a Laser Arc deposition plant are discussed. On optical, electrical and mechanical properties of DLC and aluminia layers produced by different parameters will be reported.
11:30 AM		B4-10 Design of Nanostructured B-C-N Films for Tribological Applications H.W. Holleck, A. Kratzsch, H. Leiste, M. Stueber, S. Ulrich (Forschungszentrum Karlsruhe, Germany) The ternary system B-C-N is characterized by the two binary compounds BN and B4C and two phase equilibria between BN-B4C and BN-C. Beside the stable compounds B4C and h-BN, the metastable phases diamond, c-BN and CNx, belonging to the group of superhard materials, are of particular interest for thin films for tribological applications. The structures of carbon and BN are closely related in the stable graphitic as well as in the metastable diamond like state. Thermodynamic calculations in the ternary system show, that a metastabel ternary c-BCN phase is only slightly less stable than a metastable h-BCN phase and the stable two phase equilibrium. It was therefore of particular interest to investigate the constitution of ternary BCN thin films obtained by vapor quenching. BCN films were deposited by reactive and nonreactive magnetron sputtering from B/C/N targets under variation of the target composition, substrate temperature, deposition rate and the ion bombardement. Multiphase nanostructured thin films with crystalline and amorphous phases were obtained. The phase composition was strongly dependent on the substrate temperature and the ion bombardement. Superhard c-BN phases embedded in a lubricant graphitic and amorphous C- and BCN matrix could be prepared. These films are characterized by a hardness of up to 2.6 GPa and frictions coefficients (against steel and Al2O3) between the values of c-BN(µ =0.5) and amorphous carbon (µ=0.1). Films with high amounts of c-BN were characterized by high residual stresses and low critical loads of failure. By a graded layer concept, with increasing ion energies from 25 to 275 eV during depsition, films with high hardness and good adhesion (critical load of failure: 50N) could be obtained Thermodynamics, kinetics and the nanostructures of BCN films will be discussed and related to properties and performance.
11:50 AM		B4-11 Dynamic of a Pulsed DC Glow-Discharge Used for Plasma-CVD T.A. Beer, J. Laimer, H. Stoeri (Technische Universitaet Wien, Austria) Pulsed direct-current (d.c.) glow discharges are commonly used in systems for plasma-enhanced chemical vapor deposition (Plasma-CVD). In the present work we investigate the time-development of pulsed d.c. plasmas relevant for the production of TiN coatings by PACVD. A videocamera with gateable image-intensifier is used for studying the spatial and temporal evolution of the light-intensity of the plasma. Additionally, we use a single electrostatic probe to determine a time resolved charged particle distribution of the plasma during the pulses and the afterglow. In the presence of electronegative species like TiCl4, the ignition of the plasma in each pulse is slow. The plasma ignites at the beginning of each pulse at one spot, where a positive column is observed, and spreads from there across the substrate surface. The pattern of the spatial-temporal evolution is quite complex and the evolution of the negative glow depends on various parameter, including geometry. The observed delay in the plasma formation is in the range of 10 us to 130 us. The delay is quite sensitive to voltage, pulse-times, gas-mixture, geometry and placement of the substrate. This phenomenon is most likely responsible for inhomogeneous distribution of quality and thickness of coatings. Langmuir-probe measurements demonstrate the conversion of electrons into negative ions during the time interval between the pulses.