Papers

ICMCTF2004 Session G3: Atmospheric Plasma, Hollow Cathode and Hybrid Plasma Processing

Tuesday, April 20, 2004 8:30 AM in Room Sunrise

Tuesday Morning

Start	Invited?	Item
8:30 AM		G3-1 Hybrid Vapor Deposition Processes P.M. Martin, G.L. Graff, M.E. Gross (Pacific Northwest National Laboratory) Magnetron sputtering has been combined with polymer flash evaporation and electron beam evaporation to form two hybrid deposition processes. The hybrid processes combine the advantages of each deposition process; high deposition rate for electron beam evaporation and polymer flash evaporation, high density, excellent property control and range of materials for magnetron sputtering, and low cost processing for polymer flash evaporation. Applications of the hybrid polymer/inorganic coating process include permeation barrier coatings for organic electronics, solar cells and thin film batteries, optical coatings on flexible plastics, multilayer capacitors, and magnetic multilayers. The hybrid magnetron sputtering/e-beam process is particularly well suited for precision multilayer optical coatings involving high index materials such as silicon,germanium, hydrogenated silicon and germanium, titania, niobia and low index materials such as calcium fluoride, hafnium fluoride, and magnesium fluoride. Deposition of fluorides by magnetron sputtering is difficult due to negative ion resupttering effects. Examples of an ultrabarrier coating for organic displays and NIR edge filters will be presented.}
9:10 AM		G3-3 High Rate Hot Hollow Cathode Arc Deposition of Chromium and Chromiun Nitride Films H. Baránková, L. Bardos, L.-E. Gustavsson (Uppsala University, Sweden) The hollow cathode in the diffuse arc regime (hot cathode arc) was used for deposition of chromium and chromium nitride films. The chromium hollow cathode serving as a gas inlet was connected to a radio frequency (Rf) generator with the Rf power up to 300 W. The temperature of the hollow cathode outlet reached 1400°C. The texture, structure and mechanical properties of both Cr and CrN films deposited at different Rf powers were studied in more details. Films were deposited on unheated silicon and steel substrates. It was found that the contribution of the Cr₂N phase decreased with increasing Rf power and the hard, highly textured (111) crystalline CrN films with thickness of 45 µm could be deposited at rates as high as 2.5 µm/min. These deposition rates exceed rates of TiN films deposited at comparable conditions. The process parameters and film properties are very promising for industrial applications of the hot hollow cathode arcs generated by the linear magnetized hollow cathodes.
9:30 AM		G3-4 Microwave and Hybrid Laser Atmospheric Plasma Processing J. Lucas (University of Liverpool, United Kingdom) Either arcs or lasers presently produce industrial atmospheric plasma. In the arc process, striking the arc between a metal electrode and the workpiece generates the plasma. As the process is energy efficient, it is widely applied in joining but it can only be applied to metals and the heat source is quite diffuse. The plasma produced by the laser process is more focussed and can be used with both metals and non-metals but the equipment is very expensive. The recently developed microwave plasma process equipment is similar to the arc equipment in size. However, the microwave generated plasma process is closer to the laser plasma in performance but has the low cost and energy efficiency attributes of the arc process. The microwave plasma, either alone or jointly with laser power, is used for material welding and cutting. However, more importantly it has opened up an additional range of novel applications such as the production of high temperature ceramic particles including carbon nanoparticles as well as thermal spraying and plasma chemical processing. The microwave plasma/laser plasma hybrid systems allow high precision and fast material processing activities to be undertaken at a lower cost than by laser plasma.
10:10 AM		G3-6 Microwave-Laser Hybrid Processing of Materials A. Badzian, R. Peelamedu, R. Roy, R.P. Martukanitz (The Pennsylvania State University) A combination of laser beam and microwave electromagnetic field appears to be a new approach for processing of materials. The talk will be focused on sintering of zirconia. A multimode microwave cavity (2.45GHz) and Nd:YAG pulsed laser radiation have been used in sintering experiments. Microwave field was applied first to heat zirconia pellet followed by laser radiaton while maintaining the microwave power at steady level. The laser ilumination took 2-4 min and during laser irradiation the temperature of the pellet rose up to 1800C rapidly. SEM images revealed zirconia nanograins averaging to about 25nm, without any observable cracks. The novelty of a hybrid microwave-laser approach is seen in the synergism of physical and chemical phenomena created by these two diffetent electromagnetic fields. This method can be useful in fabrication of nanocomposits because of the limited grain growth of nanograins during of such short process.
10:30 AM		G3-7 Deposition of Silicon Nitride Films for Solar Cells by Atmospheric Pressure Chemical Vapor Deposition, Thin Film and Plasma Compositions C. Amato-Wierda, C. Blais (University of New Hampshire) Silicon nitride thin films for solar cell applications have been deposited using an atmospheric pressure chemical vapor deposition technique. The key feature of our process is a dielectric barrier discharge sustained at atmospheric pressure with silane, ammonia, and hydrogen gases. This process provides a simple, continuous, non-vacuum, and large volume process that would be more suitable to the solar cell industry compared to conventional vacuum techniques. Silicon nitride films have been deposited which are silicon-rich, and contain less than 1% oxygen, and 1-4% carbon. Deposition rates as high as 50 nm/min have been obtained. The atomic composition of the films has been investigated as a function of various process parameters, including relative amounts of silane and ammonia, and power. Additionally, the consumption of silane and ammonia was monitored by mass spectrometry under various conditions.
10:50 AM		G3-8 Plasma Polymerisation of Hybrid Organic-inorganic Monomers in an Atmospheric Pressure Dielectric Barrier Discharge O Goossens, S. Paulussen, D. Vangeneugden (VITO, Belgium) Plasma polymerisations of hybrid organic-inorganic monomers were performed in a dielectric barrier discharge at atmospheric pressure. Although widely investigated for many years, plasma polymers are still not well understood with respect to their physical and chemical properties. In particular, this is true for the more recently developed deposition technologies based on atmospheric pressure plasmas. The presented work deals with plasma polymer films obtained from tetraethoxysilane (TEOS), glycidoxypropyltrimethoxysilane (GLYMO), methacryloxypropyl-trimethoxysilane (MEMO) and propyltrimethoxysilane (PTMO) under various process conditions. A detailed study of the plasma polymer films obtained was performed to determine chemical composition, structure and surface morphology. Physical properties of the obtained films were characterised by field emission scanning electron microscopy (FESEM) and surface energy measurements. On the other hand, chemical properties were characterised by means of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). In this way the structural retention of the initial monomer in the obtained plasma polymer could be evaluated. It was found that plasma polymer films obtained at atmospheric pressure differ significantly from their classic chemical counterparts with respect to chemical composition and degree of crosslinking. More in particular, a higher degree of crosslinking could be obtained compared to polymerisation processes that are available today.
11:10 AM		G3-9 Plasma Polymerization in a Microwave Reactor at Atmospheric Pressure S. Datta (Procter & Gamble); V. Shanov (University of Cincinnati); S.F. Miralai (Procter & Gamble) Microwave plasma at low pressures have been extensively studies in the literature and are known for their high chemical activities due to the high generation rate of reactive species. In contrast, microwave discharges at high pressures is relatively new and has been used mainly as excitation source for dissociative processes and spectrochemical analysis for use in environmentally oriented applications such as abatement of CFC's and NOx destruction, due to their high temperatures. In this paper, we will investigate a new application of atmospheric pressure microwave discharges, namely post discharge plasma polymerization of Fluorocarbon monomers, for production of hydrophobic coatings. In our study, the bulk chemistry of the coatings was determined by using FTIR analysis, while the surface chemistry and functional group retention was investigated using X-Ray Photoelectron Spectroscopy (XPS). The coatings were found to replicate the structure of the monomer, as shown by FTIR analysis. The deposition thickness and topology of the coatings are estimated by AFM while sureface energy determination using sessile drop technique exhibited hydrophobic polymer coatings with low surface energy. The variation of the surface energy as a function of applied MW power is discussed in terms of CF₂/CF₃ ratio and the functional retention of the monomer structure.