Process simulation of industrial vacuum arc deposition

Vacuum deposition and especially vacuum arc deposition represent efficient methods to produce protective or decorative coatings and are now widely used for industrial applications. An advantage consists in the nearly collision-free propagat ion allowing high energies of the film forming particles. However, the straight expansion of the energetic plasma means that a homogeneous deposition 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 modeling 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. 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

Lasermaterialbearbeitung mit Industrierobotern

You see a demonstration of a laser material processing equipment with a six-axial industrial robot which puts for different processing tasks a CO2 laser with a high beam quality, a pw-CO2 laser as well as diode lasers at your disposition. A telescopic arm transfers the beam power to the work piece. To compensate the positioning deviations of the robot which are greater than those of Cartesian systems with axial co-ordinates, sensor assisted positioning systems are used for laser beam welding. The off-line programming and the test of the processing programs are realised with a simulation system

Scale-up of pulsed laser deposition -PLD- for 4-wafer coating: Vortrag Symposium F, COLA '95.

PLD of uniform thin films on 4-wafers has been realized by the integration of a PLD-source into a commercial MBE-system. Thickness homogeneity over the total substrate area is obtained by precise spatial control of the plasma plumes excited simultaneously at two or more adjacent target locations. Computer controlled motion of a cylindrical target with respect to the stationary focal spots of the laser beams, has to provide (a) a suitable deflection of the plume axis and (b) a uniform target erosion. Process control was investigated by computer simulations. The efficiency of the two techniques for large-area coating described in this paper is illustrated by the preparation of DLC thin film specimens and their ellipsometric characterization. Special film thickness gradients were realized by a particular regime of target and substrate motion

Integration of a pulsed laser deposition source into a conventional MBE-system to produce multilayersystems on a NM-scale

The conventional thin film deposition equipment of PLD has been modified for the preparation of individual thin solid films and nanometer - layer stacks of uniform thickness across 4"-substrates. Therefore the planar target configuration was replaced by a cylindrical one and the target motion regime has been improved to provide a precise spatial control of the plasma plume orientation.During thin film deposition a substrate translation is preferred instead of the usual rotation technique. With this arrangement the emission characteristic of the plasmasource can be computer controlled and the desired coating can be tailored via a stepper-motor-driven manipulator for the desired layer thickness profile across an extended substrate. Thus, for example, a homogeneous film thickness is obtained even for lower target/substrate distances, and an appropriate deposition rate can be maintained.In a second version this cylinder geometry principle of plasma plume control by target surface morpholog y is extended to a spatial solution. Thus the hemisphericaltarget surface becomes the basic element for inside wall coating of tubes or even more complex hollow bodies.First applications of the equipment are explained and compared with typical results of the conventional technique

Theoretical description of pulse laser deposition as a new thin film technique

Theoretical and experimental results are presented for the pulse laser deposition techniques. The properties of the particle flow are determined from the interaction of the laser beam with the solid and the expanding plasma plum

Pulsed laser deposition of x-Ray optical layer stacks with atomically flat interfaces

Pulsed laser deposition is described as a technique for the synthesis of multilayer showing X-ray optical quality. The state of the art is characterized by results that demonstrate a development of the instrumental basis superior to that of conventional PLD systems. Multilayers of the Ni/C-, Mo/Si- and W/C-types prove the versatility of the method and the output of layer stack characterization by HREM SPM, XD, AES, XPS, ellipsometry and image processing ensures a high quality with regard to stack regularity, layer homogeneity and interface smoothness

Laser pulse vapour deposition of metal-carbon superlattices for soft X-ray mirror applications

The paper describes first results wiht a new designed target/substrate/handling system for LPVD of multilayer structures with a good thickness homogenity. Resulting thickness profiles calculated for various handling regimes show a substantial thickness homogeneization as compared to the conventional arrangement. For the preparation of various thin solid films (C, Ni) and C/Ni-multilayers a Nd-YAG-laser (wavelength 1064 nm, pulse energy 0.9 J, pulse length 7 ns, repetition rate 30 Hz) was used. The layers were characterized by ellipsometry, X-ray diffraction, TEM cross-section

Optical and photoemission studies of DLC films prepared with a systematic variation of the sp3: sp2 composition

The optical and photoemission properties of hydrogen-free DLC films prepared under conditions which result in different types of carbon bonding (previously determined from electron energy loss spectroscopy) are reported. The films were prepared using a mass selected ion beam deposition system covering the C+ energy range 10 eV - 2 keV, mostly on Si held at room temperature. Previous measurements have shown that the sp3 content of these films varied from 0 to > 80 per cent. The optical constants (n, k absorption coefficient (a)) of theses films were measured by ellipsometry. The energy gaps were derived from Tauc plots (Eg) and from alpha = 10(exp4) cm(exp-1) values (E(0.4)). The enrgy gaps were found to vary with the sp3 content from E < 1 eV (10 per cent sp3) up to E = 2,4 eV (85 per cent sp3). The photoemission absolute quantum efficiencies of these films were independently measured in the UV region using a monochromator system and were compared to those of CVD diamond films and grap hite