In order to establish economic coating technologies for mass-produced materials, the widely used, microwave plasma-enhanced (PE) CVD technology has been extended to atmospheric pressure operation. Microwave plasma activation substantially widens the range of potential applications compared to conventional atmospheric CVD, because it is capable of processing temperaturesensitive substrates. A cylinder-type microwave cavity was scaled-up to different working diameters. The half-meter range has already been achieved, and further scale-up potential can be demonstrated. The microwave source offers access to a spatially extended, homogeneous, stable, non-thermal plasma, even in the downstream region. A range of gases can be used for plasma excitation, and the emanating plasma is clean because there is negligible wall interaction. Fluid dynamics modeling was used as a tool for both reactor design and process optimization. In-situ process characterization was provided by spectroscopic methods (optical emission spectra (OES), Fourier-transform infrared (FTIR)) and a range of atomic and molecular intermediates, precursor fragments, and reaction products were identified. A deep precursor fragmentation occurs in the remote plasma region leading to inorganic layer materials. Silica layers were deposited on stainless steel and glass. Deposition rates were in the range 15±100 nm s ±1 (static) and 0.3±2.0 nm m s ±1 (dynamic). Layer properties were determined by spectroscopic ellipsometry and FTIR reflectance spectroscopy, elastic recoil detection analysis (ERDA), and nano-indentation. The optical properties and the network structure of the silica layers on both substrates are close to bulk silica.

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.

Boron carbide (B4C) is one of the few materials that is expected to be most resilient with respect to the extremely high brilliance of the photon beam generated by free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at light source facilities, B4C-coated optics are subject to ubiquitous carbon contaminations. Carbon contaminations represent a serious issue for the operation of FEL beamlines due to severe reduction of photon flux, beam coherence, creation of destructive interference, and scattering losses. A variety of B4C cleaning technologies were developed at different laboratories with varying success. We present a study regarding the low-pressure RF plasma cleaning of carbon contaminated B4C test samples via inductively coupled O2/Ar, H2/Ar, and pure O2 RF plasma produced following previous studies using the same ibss GV10x downstream plasma source. Results regarding the chemistry, morphology as well as other aspects of the B4C optical coating before and after the plasma cleaning are reported. We conclude that among the above plasma processes only plasma based on pure O2 feedstock gas exhibits the required chemical selectivity for maintaining the integrity of the B4C optical coatings.

Plasmaprozesse werden für eine Vielzahl von Oberflächenmodifizierungen eingesetzt, typische Beispiele sind Beschichtungen für einen verbesserten Korrosions‐ und Kratzschutz oder die Oberflächenreinigung und ‐texturierung. Da diese Prozesse jedoch in der Regel im Vakuum ablaufen, sind sie für viele großflächige industrielle Anwendungen nicht anwendbar. Plasmagestützte CVD‐Prozesse bei Atmosphärendruck (AP‐PECVD) ermöglichen die Herstellung von Bauteilen und Halbzeugen mit Funktionsschichten im Durchlaufverfahren ohne kostenintensiven Einsatz von Vakuumanlagen. Durch Integration in in‐line‐Produktionsprozesse reduzieren sich Substrathandhabungs‐ und Beschichtungskosten.Eine thermische Plasmaquelle, basierend auf einer linear ausgedehnten DC‐Bogenentladung bei Atmosphärendruck, wurde für einen kontinuierlichen PECVD‐Prozess zur Abscheidung von Siliziumnitrid bei Substrattemperaturen unterhalb von 300 °C sowie zum plasmachemischen Ätzen und Texturieren von Silizium untersucht.

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