			Home About us Contact

Plasma Source (plasma + source)

Distribution by Scientific Domains

Polymers and Materials Science	66%
Physics and Astronomy	25%

Selected Abstracts

An Integrated Atmospheric Microwave Plasma Source

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Reinhold Kovacs
Abstract Atmospheric plasma processes become more and more popular in recent times. A new integrated atmospheric plasma source is presented which consists of a microwave resonator combined with a solid-state power oscillator. This allows for a very compact and efficient design of a microwave plasma source without external microwave power supply and matching units. Hydrophobic polymers have to be activated to ensure an effective painting or glueing. The performance of this new plasma source has been investigated with respect to surface activation depending on axial and radial distance to the substrate, process time, process gas, and flow velocity. Several polymeric materials have been compared. Polyethylene, polyamide, polystyrene, polypropylene, polycarbonate, and polytetrafluorineethylene show good activation results. This tool can be used especially for bulky goods and/or mass products, when a vacuum process is not possible or too expensive. [source]

Generation of Thin Surface Plasma Layers for Atmospheric-Pressure Surface Treatments

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2004
ernák
Abstract Thin layers of atmospheric-pressure non-equilibrium plasma can be generated by pulse surface corona discharges and surface barrier discharges developing on the treated surfaces or brought into a close contact with the treated surfaces. Plasma sources based on these discharge types have the potential of meeting the basic on-line production requirements in the industry and can be useful for a wide range of surface treatments and deposition processes including continuous treatment of textiles. Comparing with atmospheric pressure glow discharge sources, the potential advantages of these plasma sources include their simplicity, robustness, and capability to process in a wide range of working gases. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Comparison of deep level incorporation in ammonia and rf-plasma assisted molecular beam epitaxy n-GaN films

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
A. R. Arehart
Abstract The use of rf-plasma and ammonia nitrogen sources for growth of GaN films by molecular beam epitaxy (MBE) are compared in terms of defect incorporation using deep level optical spectroscopy (DLOS) and deep level transient spectroscopy (DLTS). To better improve the understanding of ammonia-based MBE growth of GaN and potential defect sources as opposed to the more studied plasma source-based MBE-grown material several V/III ratios were also investigated, which were generated via systematic adjustment of the ammonia flow rates during growth. The DLOS spectra, comparing deep traps within the n-GaN grown using N-plasma and ammonia sources, reveal the presence of the same deep levels due to background carbon and gallium vacancies, with energy levels at EC -3.28, EC -2.62, and EC -1.28. The DLTS results of the N-plasma and ammonia-based MBE samples show two similarly dominant electron traps at EC -0.60, and EC -0.24 in each sample. Measurements made as a function of V/III flux ratio for ammonia-based MBE growth indicate a large dependence of the EC -0.24 eV trap concentration on growth flux ratio, which is significant for guiding continued optimization of this promising MBE growth method for GaN devices. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

An Integrated Atmospheric Microwave Plasma Source

Plasma-Assisted Atomic Layer Deposition of Al2O3 at Room Temperature

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Tommi O. Kääriäinen
Abstract A new design of plasma source has been used for the plasma-assisted atomic layer deposition (PA-ALD) of Al2O3 films at room temperature. In this PA-ALD reactor the plasma is generated by capacitive coupling directly in the deposition chamber adjacent to the substrate but can be separated from it by a grid to reduce the ion bombardment while maintaining the flow of radicals directly to the substrate surface. During the ALD cycle a mixture of nitrogen and argon was introduced into the reactor to act as a purge gas between precursor pulses and to facilitate the generation of a plasma during the plasma cycle. Sequential exposures of TMA and excited O2 precursors were used to deposit Al2O3 films on Si(100) substrates. A plasma discharge was activated during the oxygen gas pulse to form radicals in the reactor space. The experiments showed that the growth rate of the film increased with increasing plasma power and with increasing O2 pulse length before saturating at higher power and longer O2 pulse length. The growth rate saturated at the level of 1.78 Å·cycle,1. EDS analysis showed that the films were oxygen rich and had carbon as an impurity. This can be explained by the presence of bonds between hydrocarbons from the unreacted TMA precursor and excess oxygen in the film. ATR-FTIR spectroscopy measurements indicated a change in growth mechanism when the distance between the location of the radical generation and the substrate was varied. A similar effect was observed with the use of different plasma power levels. [source]

Inactivation of Bacteria by the Plasma Pencil

PLASMA PROCESSES AND POLYMERS, Issue 6-7 2006
Mounir Laroussi
Abstract Summary: A device capable of generating a relatively long cold plasma plume has recently been developed. The advantages of this device are: plasma controllability and stability, room temperature and atmospheric pressure operation, and low power consumption. These features are what is required from a plasma source to be used reliably in material processing applications, including the biomedical applications. In this communication we describe the device and we present evidence that it can be used successfully to inactivate Escherechia coli in a targeted fashion. More recent experiments have shown that this device inactivates other bacteria also, but these will be reported in the future. Photograph of a He plasma plume launched out of the plasma pencil. [source]

Probe Diagnostics of Expanding Plasmas at Low Gas Pressure

PLASMA PROCESSES AND POLYMERS, Issue 2 2006
Mariya Dimitrova
Abstract Summary: Results from tandem-type probe diagnostics of a plasma source based on an inductive discharge are presented in this study. The driver region is in the classical form of a cylindrically shaped inductive discharge, with a coil positioned over a gas discharge tube, whereas a bigger metal chamber provides volume for plasma expansion. Low pressure argon discharges were studied. The axial profiles of the plasma parameters were measured in the discharge in the metal chamber. The results obtained show that decreasing electron temperature and plasma density with increasing distance from the driver characterizes the behavior of the expanding plasmas. Moreover, two regions with different rates of variation of the plasma parameters complete the plasma expansion volume: a faster drop close to the driver and slow axial changes away from it. The gas pressure and power applied for the discharge maintenance were the external parameters varied. Axial profiles of the electron concentration in the plasma expansion region of an inductive discharge. [source]

Plasma facilitated delivery of DNA to skin

BIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009
Richard J. Connolly
Abstract Non-viral delivery of cell-impermeant drugs and DNA in vivo has traditionally relied upon either chemical or physical stress applied directly to target tissues. Physical methods typically use contact between an applicator, or electrode, and the target tissue and may involve patient discomfort. To overcome contact-dependent limitations of such delivery methodologies, an atmospheric helium plasma source was developed to deposit plasma products onto localized treatment sites. Experiments performed in murine skin showed that samples injected with plasmid DNA encoding luciferase and treated with plasma demonstrated increased levels of expression relative to skin samples that received injections of DNA alone. Increased response relative to injection alone was observed when either positive or negative voltage was used to generate the helium plasma. Quantitative results over a 26-day follow-up period showed that luciferase levels as high as 19-fold greater than the levels obtained by DNA injection alone could be achieved. These findings indicate that plasmas may compete with other physical delivery methodologies when skin is the target tissue. Biotechnol. Bioeng. 2009; 104: 1034,1040. © 2009 Wiley Periodicals, Inc. [source]

Linear Extended ArcJet-CVD , a New PECVD Approach for Continuous Wide Area Coating Under Atmospheric Pressure,

CHEMICAL VAPOR DEPOSITION, Issue 11-12 2005
V. Hopfe
Abstract A new type of DC-powered plasma source (LARGE) was developed and evaluated for continuous plasma-enhanced (PE) CVD under atmospheric pressure. The linear extended emanating plasma sheet was scaled-up to various working widths with the result that a half meter range has already been achieved. A CVD reactor was designed for continuous deposition of non-oxide materials. The reactor operates in a remote atmospheric pressure (AP) PECVD configuration with typical deposition rates of 5,50,nm,s,1 (static) and 0.1,1.0,nm,m,s,1 (dynamic). The potential application range of the ArcJet-CVD technology was evaluated by screening studies with various substrates, (stainless steel, glass, silicon wafers) and coating materials (silica, carbon, silicon nitride). In-situ process characterization has been provided by both optical emission and Fourier transform infrared (FTIR) spectroscopy. A range of atomic and molecular intermediates, precursor fragments, and reaction products were identified, leading to the conclusion that a complete conversion of the element-organic precursors into an inorganic layer takes place. [source]

Generation of Thin Surface Plasma Layers for Atmospheric-Pressure Surface Treatments

Atmospheric Pressure Plasma Deposition of Adhesion Promotion Layers on Aluminium

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Philipp Bringmann
Abstract The paper presents investigations on the deposition of plasma polymerised films at atmospheric pressure as a pretreatment for painting and adhesive bonding of aircraft aluminium structures. Two different plasma jet sources are employed, one based on a controlled arc discharge and air as process gas, and another based on a dielectric barrier discharge (DBD) and He as plasma gas. The organosilicon precursors HMDSO, TEOS and OMCTS are used with both plasma sources. Deposition in the arc discharge plasma jet leads to almost carbon-free silica coatings, whereas coatings deposited with the DBD jet source contain a high amount of carbon, varying with precursor type. The obtained results of corrosion investigations and adhesion tests are promising, as some representative aircraft industry requirements could be achieved. However, the investigations show a strong dependency on the used precursor and type of polymer (paint or adhesive) applied on the plasma polymerised film. [source]

Trends in Combining Techniques for the Deposition of New Application-Tailored Thin Films

PLASMA PROCESSES AND POLYMERS, Issue 3 2007
Gheorghe Dinescu
Abstract A modern approach for the development of thin film deposition technology is to combine the classical principles of PVD and CVD techniques, and to assist them with the recent progress in plasma sources and reactors. The power of inter-combining the deposition methods with new ideas and tools is discussed for a particular number of cases, such as the combination of magnetron sputtering with pulsed ion implantation, of pulsed laser deposition with low-pressure radiofrequency directional plasma beams, and of magnetron sputtering with plasma-beam-enhanced chemical vapor deposition. The discussed cases are complemented with examples from literature, highlighting the recent trends in combining plasma based deposition techniques, and the need for an improvement in the terminology. [source]