Plasma processing

Plasma processing is a plasma-based material processing technology that aims at modifying the chemical and physical properties of a surface. Plasma processing techniques include: *Plasma activation *Plasma ashing *Plasma cleaning *Plasma electrolytic oxidation *Plasma etching *Plasma functionalization *Plasma polymerization *Corona treatment *Plasma modification Related topics are plasma chemistry, chemical vapor deposition, and physical vapor deposition processes like sputter deposition, plasma iondoping, vacuum plasmaspraying, and reactive ion etching. See also *List of plasma (physics) applications articles

Experimental benchmark of the NINJA code for application to the Linac4 H-ion source plasma

Stefano Mattei, Minh Quang Tran

For a dedicated performance optimization of negative hydrogen ion sources applied at particle accelerators, a detailed assessment of the plasma processes is required. Due to the compact design of these sources, diagnostic access is typically limited to optical emission spectroscopy yielding only line-of-sight integrated results. In order to allow for a spatially resolved investigation, the electromagnetic particle-in-cell Monte Carlo collision code NINJA has been developed for the Linac4 ion source at CERN. This code considers the RF field generated by the ICP coil as well as the external static magnetic fields and calculates self-consistently the resulting discharge properties. NINJA is benchmarked at the diagnostically well accessible lab experiment CHARLIE Concept studies forHelicon Assisted RF Low pressure Ion sourcEs) at varying RF power and gas pressure. A good general agreement is observed between experiment and simulation although the simulated electron density trends for varying pressure and power as well as the absolute electron temperature values deviate slightly from the measured ones. This can be explained by the assumption of strong inductive coupling in NINJA, whereas the CHARLIE discharges show the characteristics of loosely coupled plasmas. For the Linac4 plasma, this assumption is valid. Accordingly, both the absolute values of the accessible plasma parameters and their trends for varying RF power agree well in measurement and simulation. At varying RF power, the H- current extracted from the Linac4 source peaks at 40. kW. For volume operation, this is perfectly reflected by assessing the processes in front of the extraction aperture based on the simulation results where the highest H- density is obtained for the same power level. In surface operation, the production of negative hydrogen ions at the converter surface can only be considered by specialized beam formation codes, which require plasma parameters as input. It has been demonstrated that this input can be provided reliably by the NINJA code.

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2017

Plasma generation by inductive coupling with a planar resonant RF network antenna

Philippe Frédérique Bruno Guittienne, Christoph Hollenstein, Alan Howling, Sylvain Lecoultre

A planar antenna operating at 13.56MHz is presented for potential applications in plasma processing. It consists of interconnected elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna exhibits a set of resonant modes associated with peaks of the real input impedance. Each mode is defined by its particular distribution of current and voltage oscillating at the frequency of the mode. A rectangular antenna of 0.55m x 0.20m has been built and first results obtained with argon plasmas are presented. Efficient plasma generation is shown by plasma densities above 3 x 10(17) m(-3) at 2000 W with reasonable uniformity over the antenna area. The plasma couples inductively with the resonating currents flowing in the antenna above a threshold power of about 60 W. The real input impedance at antenna resonance avoids the problem of strong reactive currents and voltages in the matching box and RF power connections associated with conventional large-area plasma sources. Resonant RF networks have a strong potential interest for various designs of plasma sources.

2012

Experimental benchmark of the NINJA code for application to the Linac4 H-ion source plasma

Stefano Mattei, Minh Quang Tran

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2017

Modification of Contact Lenses by Plasma Processes

Experimental benchmark of the NINJA code for application to the Linac4 H-ion source plasma

Plasma generation by inductive coupling with a planar resonant RF network antenna

Modification of Contact Lenses by Plasma Processes

Plasma generation by inductive coupling with a planar resonant RF network antenna

Experimental benchmark of the NINJA code for application to the Linac4 H-ion source plasma