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Hydrocarbon contamination is associated with light transmission losses in modern lithography machines, which contain extreme-ultraviolet-induced plasma. A volume-averaged global and deposition/etch surface model of a reference hydrogen/methane inductive discharge is developed to investigate the plasma–surface interactions. The simulation results are validated against a wide variety of experiments and verified with respect to multiple sets of computational data. The deposition rate is calculated for a variation in methane impurity (10–10 000 ppm), power, pressure, and net mass flow. The simulations conclude that the hydrocarbon plasma deposition can be minimized by reducing methane impurity and excluding solid organic structures. [ABSTRACT FROM AUTHOR]

Hydrogen is often envisioned as a green fuel and energy carrier. However, a greenhouse gas‐free production method is still needed for this purpose. A promising method is the pyrolysis of methane. In this study, we present the three‐dimensional simulation of methane pyrolysis in a microwave plasma torch operated in an argon–methane mixture. Due to the high gas temperatures, the chemistry is dominated by reactions between neutral particles. Therefore, the plasma is treated only as a heat source using space‐resolved gas temperature measurements as input. The end‐of‐pipe results of the simulation are compared to measured values, showing good agreement for methane conversion. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) etching of materials by plasmas is an ultimate challenge in microstructuring applications. A method is proposed to reach a controllable 3D structure by using masks in front of the surface in a plasma etch reactor in combination with local magnetic fields to steer the incident ions in the plasma sheath region toward the surface to reach 3D directionality during etching and deposition. This effect has the potential to be controlled by modifying the magnetic field and/or plasma properties to adjust the relationship between sheath thickness and mask feature size. However, because the guiding length scale is the plasma sheath thickness, which for typical plasma densities is at least tens of micrometers or larger, controlled directional etching and deposition target the field of microstructuring, e.g., of solids for sensors, optics, or microfluidics. In this proof-of-concept study, it is shown that E → × B → drifts tailor the local sheath expansion, thereby controlling the plasma density distribution and the transport when the plasma penetrates the mask during an RF cycle. This modified local plasma creates a 3D etch profile. This is shown experimentally as well as using 2d3v particle-in-cell/Monte Carlo collisions simulation. [ABSTRACT FROM AUTHOR]

This feature article presents recent results on the analysis of plasma/polymer interactions and the nucleation of ultra‐thin plasma films on polymeric substrates. Because of their high importance for the understanding of such processes, in situ analytical approaches of the plasma volume as well as the plasma/substrate interfaces are introduced before the findings on plasma surface chemistry. The plasma activation of polymeric substrates is divided into the understanding of fundamental processes on model substrates and the relevance of polymer surface complexity. Concerning thin film nucleation and growth, both plasma‐enhanced chemical vapor deposition and plasma‐enhanced atomic layer deposition processes as well as the combination of both processes are considered both for model substrates and technical polymers. Based on the comprehensive presentation of recent results, selective perspectives of this research field are discussed. [ABSTRACT FROM AUTHOR]

Zirconia layers are often used as thermal barriers. In recent years, depositions by chemical vapor deposition methods using a metalorganic precursor (MOCVD) have been primarily investigated. Here, we combine MOCVD with plasma activation ‐ plasma‐enhanced chemical vapor deposition (PECVD]) ‐ of the gas phase and/or the growth surface to lower the growth temperature and to allow for a flexible coating design. PECVD causes the precursor to be transformed into a chemically active species, yielding thin films with a five times higher sticking coefficient compared to MOCVD. This leads to the onset of crystallization at lower surface temperatures. Carbon is incorporated at oxygen sites, so that the crystalline structure of zirconia is preserved, but the electrical conductivity is affected. The thermal conductivity is like that of pure zirconia. [ABSTRACT FROM AUTHOR]

Carbon containing zirconia films are deposited from chemical vapor deposition (CVD) and from plasma enhanced chemical vapor deposition (PECVD), as being used as thermal barrier coatings for many applications. Their thermal conductivity has been measured for temperatures ranging from room temperature up to 450 K using the 3 ω method. It is shown that the samples exhibit a lattice and an electronic contribution to the thermal conductivity reaching values up to 13 W/m/K for samples from CVD and up to 5 W/m/K for the samples from PECVD at 450 K. At room temperature, the thermal conductivities for PECVD films are in the range of 1 W/m/K, whereas the CVD film shows values of 8 W/m/K. The large differences are explained by the microstructure of the films, showing smaller grain sizes with poor interfaces for the PECVD films compared to the denser CVD films. This shows that plasma deposited carbon containing zirconia films may serve as excellent thermal barriers. [ABSTRACT FROM AUTHOR]

Large language models (LLMs) like ChatGPT have the potential to revolutionize research by aiding in literature searches, data analysis, and programming tasks. LLMs can efficiently gather and filter relevant information from the internet, making them useful for interdisciplinary fields like plasma research. They can also accelerate data analysis and generate readable scientific texts. However, LLMs have limitations, such as the potential to amplify wrong statements and produce incorrect or oversimplified explanations. In plasma research, where knowledge is limited and interdisciplinary, it is crucial for scientists to use multiple sources and critically assess information. LLMs also pose challenges for scientific journals, as they can lead to the reproduction of known information and an increase in published papers. The integration of LLMs into the scientific community's workflow will require the input and guidance of critical scientists. [Extracted from the article]

Correlatively employing density functional theory and experiments congregated around high power pulsed magnetron sputtering, a plasma-surface model for metastable Cr0.8Al0.2N (space group Fm3...m) is developed. This plasma-surface model relates plasma energetics with film composition, crystal structure, mass density, stress state, and elastic properties. It is predicted that N Frenkel pairs form during Cr0.8Al0.2N growth due to high-energy ion irradiation, yielding a mass density of 5.69 g cm-3 at room temperature and Young’s modulus of 358–130 GPa in the temperature range of 50–700K for the stress-free state and about 150 GPa larger values for the compressive stress of 4 GPa. Our measurements are consistent with the quantum mechanical predictions within 5% for the mass density and 3% for Young’s modulus. The hypothesis of a stress-induced Young’s modulus change may at least in part explain the spread in the reported elasticity data ranging from 250 to 420 GPa. [ABSTRACT FROM AUTHOR]

In-vacuum characterization of magnetron targets after High Power Impulse Magnetron Sputtering (HiPIMS) has been performed by X-ray photoelectron spectroscopy (XPS). Al-Cr composite targets (circular, 50mm diameter) mounted in two different geometries were investigated: an Al target with a small Cr disk embedded at the racetrack position and a Cr target with a small Al disk embedded at the racetrack position. The HiPIMS discharge and the target surface composition were characterized in parallel for low, intermediate, and high power conditions, thus covering both the Ar-dominated and the metal-dominated HiPIMS regimes. The HiPIMS plasma was investigated using optical emission spectroscopy and fast imaging using a CCD camera; the spatially resolved XPS surface characterization was performed after in-vacuum transfer of the magnetron target to the XPS chamber. This parallel evaluation showed that (i) target redeposition of sputtered species was markedly more effective for Cr atoms than for Al atoms; (ii) oxidation at the target racetrack was observed even though the discharge ran in pure Ar gas without O2 admixture, the oxidation depended on the discharge power and target composition; and (iii) a bright emission spot fixed on top of the inserted Cr disk appeared for high power conditions. [ABSTRACT FROM AUTHOR]

Spokes are patterns of increased light emission, observed to rotate in front of the targets of magnetron sputtering discharges. They move through the plasma at velocities of several km sâˆ'1 in or against the E â†' Ă— B â†' direction of the discharge. The high velocity and their initial creation at arbitrary positions render measurements of spokes challenging. For more demanding plasma diagnostic techniques that require data acquisition over multiple discharge pulses, synchronisation to the spoke movement is necessary. In this publication, we present optical emission spectroscopy of spokes in both high power impulse magnetron sputtering (HiPIMS) as well as direct current magnetron sputtering (DCMS) discharges, performed by triggering a camera on the spoke movement. Optical filters between plasma and camera allow us to isolate emission lines of metal and working gas neutrals and ions. Based on these optical measurements and previous probe studies, the dynamics of electrons drifting through spokes in both DCMS and HiPIMS is discussed. In HiPIMS, the much shorter mean free path for inelastic electron collisions enables strong ionisation inside the spoke, causing a sudden variation in electron density which leads to the distinct spoke shape. In contrast, the spoke shape for DCMS discharges seems to rather be indicative of electron energy variations. [ABSTRACT FROM AUTHOR]

The elementary surface processes occurring on chromium targets exposed to reactive plasmas have been mimicked in beam experiments by using quantified fluxes of Ar ions (400–800 eV) and oxygen atoms and molecules. For this, quartz crystal microbalances were previously coated with Cr thin films by means of high-power pulsed magnetron sputtering. The measured growth and etching rates were fitted by flux balance equations, which provided sputter yields of around 0.05 for the compound phase and a sticking coefficient of O2 of 0.38 on the bare Cr surface. Further fitted parameters were the oxygen implantation efficiency and the density of oxidation sites at the surface. The increase in site density with a factor 4 at early phases of reactive sputtering is identified as a relevant mechanism of Cr oxidation. This ion-enhanced oxygen uptake can be attributed to Cr surface roughening and knock-on implantation of oxygen atoms deeper into the target. This work, besides providing fundamental data to control oxidation state of Cr targets, shows that the extended Berg's model constitutes a robust set of rate equations suitable to describe reactive magnetron sputtering of metals. [ABSTRACT FROM AUTHOR]

Al2O3 thin films have been deposited at substrate temperatures between 500 °C and 600 °C by reactive magnetron sputtering using an additional arbitrary substrate bias to tailor the energy distribution of the incident ions. The films were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The film structure being amorphous, nanocrystalline, or crystalline was correlated with characteristic ion energy distributions. The evolving crystalline structure is connected with different levels of displacements per atom (dpa) in the growing film as being derived from TRIM simulations. The boundary between the formation of crystalline films and amorphous or nanocrystalline films was at 0.8 dpa for a substrate temperature of 500 °C. This threshold shifts to 0.6 dpa for films grown at 550 °C. [ABSTRACT FROM AUTHOR]

Particle beam experiments were conducted in an ultra-high-vacuum vessel to mimic target poisoning during reactive magnetron sputtering of aluminum. Aluminum targets were exposed to quantified beams of argon ions, oxygen atoms and molecules, and aluminum vapour. The growth and etch rates were measured in situ by means of an Al-coated quartz crystal microbalance. The chemical state of the target surface was monitored in-situ by real-time Fourier transform infrared spectroscopy. The surface processes were modelled through a set of balance equations providing sputter yields and sticking coefficients. The results indicate that the oxygen uptake of the aluminum surface is enhanced by a factor 1 to 2 by knock-on implantation and that the deposition of aluminum is not affected by the oxidation state of the surface. [ABSTRACT FROM AUTHOR]

Plasma deposition of aluminum oxide by reactive magnetron sputtering (RMS) using an aluminum target and argon and oxygen as working gases is an important technological process. The undesired oxidation of the target itself, however, causes the so-called target poisoning, which leads to strong hysteresis effects during RMS operation. The oxidation occurs by chemisorption of oxygen atoms and molecules with a simultaneous ion bombardment being present. This heterogenous surface reaction is studied in a quantified particle beam experiment employing beams of oxygen molecules and argon ions impinging onto an aluminum-coated quartz microbalance. The oxidation and/or sputtering rates are measured with this microbalance and the resulting oxide layers are analyzed by x-ray photoelectron spectroscopy. The sticking coefficient of oxygen molecules is determined to 0.015 in the zero coverage limit. The sputtering yields of pure aluminum by argon ions are determined to 0.4, 0.62, and 0.8 at 200, 300, and 400 eV. The variation in the effective sticking coefficient and sputtering yield during the combined impact of argon ions and oxygen molecules is modeled with a set of rate equations. A good agreement is achieved if one postulates an ion-induced surface activation process, which facilitates oxygen chemisorption. This process may be identified with knock-on implantation of surface-bonded oxygen, with an electric-field-driven in-diffusion of oxygen or with an ion-enhanced surface activation process. Based on these fundamental processes, a robust set of balance equations is proposed to describe target poisoning effects in RMS. [ABSTRACT FROM AUTHOR]

The roughness evolution during plasma deposition of amorphous hydrogenated carbon (a-C:H) films is investigated. Films were deposited from an inductively coupled methane plasma using a wide range of process parameters. Plasma deposition is uniquely described by the dissipated energy per source gas molecule Emean. Depending on Emean, a specific set of radicals contributes to film growth causing a characteristic roughness development. The film roughness is measured using atomic force microscopy and spectroscopic ellipsometry and is expressed using the static and dynamic scaling coefficients α and β, respectively. For low Emean<20 eV, α∼0.65 and β∼0.19 indicating film deposition via a growth precursor with a large surface diffusion length. For Emean>20 eV, α∼0.9 and β∼0.25 indicating film deposition via a growth precursor with a small surface diffusion length. [ABSTRACT FROM AUTHOR]

The temperature dependence of the interaction of methyl radicals with the surface of a hard, amorphous hydrogenated carbon film is investigated using in situ real-time ellipsometry and infrared spectroscopy. This interaction is considered as an important process during plasma deposition of polymer-like hydrocarbon films or formation of polycrystalline diamond in methane-containing discharges. At room temperature CH[sub 3] adsorbs at sp²-coordinated CC bonds at the physical surface of the hard C:H film and forms a completely sp³-hybridized C:H adsorbate with a thickness of ∼0.17 nm. In the following, steady-state film growth is observed with a sticking coefficient of s(CH3)= 10[sup -4]. At a substrate temperature of T= 570 K, incident CH[sub 3] causes net erosion with an etching yield of Y(CH[sub 3])= 10[sup -4]. At temperatures above 650 K the sticking coefficient of CH[sub 3] becomes positive again, leading to a graphite-like C:H adsorbate. CH[sub 3] adsorption is described by a reaction scheme based on the creation of dangling bonds at the film surface via abstraction of surface-bonded hydrogen by incoming CH[sub 3] radicals. These dangling bonds act as CH3 adsorption sites at room temperature or as a precursor for chemical erosion at elevated temperature. [ABSTRACT FROM AUTHOR]

The modification of polypropylene (PP) by an argon plasma is emulated in a particle beam experiment. An ion beam deflector, used to steer argon ions from an electron‐cyclotron‐resonance (ECR) plasma source towards the sample, suppresses the UV and VUV photons generated in the plasma volume. The modification of PP surface by 200 and 500 eV ions is monitored by in situ Fourier transform infrared spectroscopy (FTIR). One observes a transition from an initial region of fast etching to a steady state without chemical modification and lower etching rate. This behavior is attributed to the progressive graphitization at the surface due to ion bombardment. An anti‐synergism arises by adding UV photons because of cross‐linking of the polymer at the subsurface region, which renders the etch rate much smaller compared to the etch rate by ion only impact. [ABSTRACT FROM AUTHOR]

The interaction of plasmas with surfaces is dominated by synergistic effects between incident ions and radicals. Film growth is accelerated by the ions, providing adsorption sites for incoming radicals. Chemical etching is accelerated by incident ions when chemical etching products are removed from the surface by ion sputtering. The latter is the essence of anisotropic etching in microelectronics, as elucidated by the seminal paper of Coburn and Winters [J. Appl. Phys. 50, 3189 (1979)]. However, ion-radical-synergisms play also an important role in a multitude of other systems, which are described in this article: (1) hydrocarbon thin film growth from methyl radicals and hydrogen atoms; (2) hydrocarbon thin film etching by ions and reactive neutrals; (3) plasma inactivation of bacteria; (4) plasma treatment of polymers; and (5) oxidation mechanisms during reactive magnetron sputtering of metal targets. All these mechanisms are unraveled by using a particle beam experiment to mimic the plasma--surface interface with the advantage of being able to control the species fluxes independently. It clearly shows that the mechanisms in action that had been described by Coburn and Winters [J. Appl. Phys. 50, 3189 (1979)] are ubiquitous. [ABSTRACT FROM AUTHOR]

A very thin oxide layer is formed on top of metal surfaces that are submitted to reactive magnetron sputtering in an oxygen atmosphere. Having a few atomic monolayers thickness (1-5nm), this oxide top layer shows properties of an electric insulator that retards the flux of incident ions. Here, the authors show that this layer can be modeled as a parallel combination of capacitance and resistance. The basic sputtering processes on the oxide layer have been mimicked by means of particle beam experiments in an ultra-high-vacuum reactor. Hence, quantified beams of argon ions and oxygen molecules have been sent to aluminum, chromium, titanium, and tantalum targets. The formation and characteristics of the oxide top layer have been monitored in situ by means of an electrostatic collector and quartz crystal microbalance. The charge build-up at the oxide layer interfaces generates a screening potential of the order of 1-10 V, which shows linear correlation with the total current through the target. The secondary electron yields of the oxides show the expected behavior with ion energies (500-1500 eV), thereby showing that this parameter is not significantly distorted by the screening potential. Charging kinetics of the oxide layer is investigated by means of time-resolved current measurements during bombardment with square-wave modulated ion fluxes. Finally, the dependence of secondary electron emission with surface oxidation state and surface charging issues in pulsed plasmas are studied within the context of the Berg's model. [ABSTRACT FROM AUTHOR]

Control of High Power Pulsed Magnetron Plasmas (HPPMS) by Monitoring Current-Voltage Characteristics High Power Pulsed Magnetron Sputtering (HPPMS) plasmas are perfectly suited for the synthesis of ceramic coatings with superior properties. This excellent performance is induced by the very peculiar energetic particle flux reaching the substrate to be coated. The ion energy distribution originates from the formation of localized ionization zones which can be imaged by fast cameras. In commercial HPPMS reactors, however, only much simpler methods such as current voltage characteristics (VI curves) are accessible. By a proper interpretation of those VI curves, it is possible to identify the favorable operation mode of an HPPMS plasma. The VI curves vary with target material, but they are sensitive to the occurrence of localized ionization zones, which represent the optimum for the operation parameter window of HPPMS plasmas. [ABSTRACT FROM AUTHOR]

Plasma processes are widely used for the deposition of thin films and/or the functionalization of material surfaces and interfaces ranging from inorganic to organic structures. The characterization of such plasma-modified surfaces is challenging and most efficiently performed by optical methods, such as FTIR-spectroscopy and related techniques. The present review aims at bridging the gap between optical spectroscopy fundamentals and the application of such experimental techniques in plasma surface science and engineering. The first part of the review covers the most relevant theoretical aspects of different reflection FTIR-spectroscopy approaches; the second part presents the different applications of these principles for the investigation of surface processes induced by plasma. The applications take into account interaction of plasma with metal surfaces, semiconductors, and polymeric materials. [ABSTRACT FROM AUTHOR]

Plasma modifications of polypropylene (PP) surfaces are analyzed by means of vacuum beam experiments. A plasma source provides Ar ion beams and a background of UV photons. Additionally, neutral oxygen beams are sent to perform reactive sputtering of PP. The etch rate and chemical state are monitored in real time by in situ Fourier transform infrared (FTIR) spectroscopy. At the onset of Ar bombardment, PP shows high sputter yields, which decrease down to a constant etch rate indicating the formation of a modified top layer. The stationary top layer is modeled as combination of a pristine fraction plus a cross-linked fraction of amorphous hydrocarbon. Photon- and ion-dominated etch processes provide different cross-linking fractions, whereas the sputter efficiency is maximized at intermediate ion energies (200 eV). [ABSTRACT FROM AUTHOR]

Modification of the surface chemistry and correlated adhesive properties of polypropylene (PP) by means of an electron cyclotron resonance (ECR) oxygen plasma source is studied based on an in situ ultra-high-vacuum (UHV)-analytical approach. To determine the plasma induced chemical changes without exposure to atmosphere, X-ray excited valence band (VB) spectroscopy and core level X-ray photoelectron spectroscopy (XPS) are performed. Adhesive properties are characterized by means of UHV chemical force microscopy (UHV-CFM). Correlation of XPS and UHV-CFM data indicate that interactions between a SiO2-tip and the modified PP surface is dominated by hydrogen bonds between surface silanol groups on the tip and induced oxidized species on PP surface. Such interactions are maximized in the initial phase of surface oxidation. [ABSTRACT FROM AUTHOR]

Characterisation of an atmospheric pressure microplasma jet in combination with simulations have been used to determine reaction mechanism of SiO2-like film formation and reaction rate constants for several gas phase reactions in the He/hexamethyldisiloxane (HMDSO)(/O2) plasma chemistry. Using a variable-length quartz tube, the gas residence time in the plasma effluent could be well controlled without changing plasma properties. A possible reaction scheme has been developed. Deposition rates, deposited profiles, carbon content of the films and the depletion of HMDSO could be reproduced by the simulation. The simulation indicates that HMDSO in He(/O2) plasma dissociates preferentially into (CH3)3SiO and Si(CH3)3, where the former radical serves as a main growth precursor. [ABSTRACT FROM AUTHOR]

The surface modification of polypropylene (PP) by monoenergetic argon ions and UV photons is evaluated in a particle beam experiment. Thereby, the polymer pre-treatment in a plasma process can be mimicked. The etching and chemical modification of the spin-coated PP thin films is monitored in real-time by in situ Fourier transform infrared spectroscopy (FTIR). It is shown that the initial exposure to the plasma ion source causes a modification of the film surface, which slows down the initially high etch rate. The separately measured UV-induced damage is more severe compared to the oxygen-containing polymer polyethylene terephthalate (PET). [ABSTRACT FROM AUTHOR]

The polymer polyethylene terephthalate (PET) has been exposed to quantified beams of argon ions and oxygen atoms and molecules. The etch rate (ER) and the surface composition of PET thin films have been analyzed by real time in situ Fourier transform infrared spectroscopy (FTIR). After the onset of the exposure of PET to the ion beam, the ER decreases rapidly by one order of magnitude irrespective of the ion energy. This slowing down of the ER is caused by cross-linking of the polymer surface. The steady state etch yields are generally orders of magnitude higher than predicted by computer calculations. The addition of oxygen to the particle flux is only changing the surface composition. At low ion energies, chemical sputtering dominates causing very high sputter yields. In addition, no threshold ion energy is observed. [ABSTRACT FROM AUTHOR]

The processes of argon retention by the target and redeposition of target material were investigated by x-ray photoelectron spectroscopy as a function of radial position for different plasma conditions in high-power impulse magnetron sputtering of aluminum targets. Significant differences in Ar radial concentration profiles were observed for different discharge conditions. Inside the racetrack area, Ar ion flux-dominated implantation is compensated by radiation-enhanced diffusion loss terms. Outside the racetrack, the role of ion implantation is diminished, and Ar retention by the target may stem from a balance between gettering by redeposited Al and ion-induced Ar desorption. [ABSTRACT FROM AUTHOR]

The deposition of thin SiO2-like films by means of atmospheric pressure microplasma jets with admixture of hexamethyldisiloxane (HMDSO) and oxygen and the role of surface reactions in film growth are investigated. Two types of microplasma jets, one with a planar electrodes and operated in helium gas and the other one with a coaxial geometry operated in argon, are used to study the deposition process. The growth rate of the film and the carbon-content in the film are measured as a function of the O2 and HMDSO admixture in the planar jet and are compared to mass spectrometry measurements of the consumption of HMDSO. Additionally, the localized nature of the jet-substrate interaction is utilized to study surface reactions by applying two jets on a rotating substrate. The addition of oxygen into the gas mixture increases HMDSO depletion and the growth rate and results in the deposition of carbon free films. The surface reaction is responsible for the carbon removal from the growing film. Moreover, carbon free films can be deposited even without addition of oxygen, when coaxial jet operated with argon is used for the surface treatment. We hypothesize that ions or excited species (metastables) could be responsible for the observed effect. [ABSTRACT FROM AUTHOR]

Low-temperature plasmas are an important tool of modern technology for deposition and erosion of thin films. In a plasma, an initial monomer is dissociated and ionized. A flux of radicals and ions emerges from the plasma and a thin film is growing or being etched by accommodation of incident radicals and ions on a substrate. Since dissociation of the initial monomer happens in the gas phase, the choice of the substrate temperature and the details of the surface structure are of minor importance. Thereby, thin films of various composition and structure on a large variety of substrates can be produced.Surface processes leading to film formation or etching are inherently heterogeneous. It is believed that the impinging flux of ions, radicals, and atoms promotes chemisorption of many species produced in the plasma. These reactions are discussed in this paper for the case of H-atom and ion-induced chemisorption of methyl radicals on hydrocarbon (C:H) film surfaces. This mimics plasma deposition of carbonaceous materials in commonly used methane plasmas, where the dominant reactive species are CH3, H, and low-energy ions.By performing particle-beam experiments it is shown that CH3 chemisorption can be quantitatively described by attachment of methyl to dangling-bond sites, which are produced either via hydrogen abstraction by incident H atoms or by ion-induced displacement of surface-bonded hydrogen. The derived absolute cross-sections are in excellent agreement with molecular dynamics calculations or predictions by computer codes based on the binary collision approximation. [Copyright &y& Elsevier]

The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications. [ABSTRACT FROM AUTHOR]

Capacitively and inductively coupled plasmas were investigated in order to deposit functional plasma polymers. Considering plasma chemical and surface processes, comparable films can be obtained with both plasma sources yielding distinctly higher deposition rates for ICP. While the gas phase processes scaled with the energy input into the plasma, the surface processes were controlled by the energy dissipated during film growth (ion bombardment). [ABSTRACT FROM AUTHOR]

Modification of an advanced ArF excimer lithographic photoresist by 400 eV Ar ion irradiation was observed in situ in real time using both infrared spectroscopy and a quartz microbalance sensor. The photoresist sputtering yields had a characteristic behavior; the sputtering yields were higher than unity at the beginning, until an ion dose of 2 × 1016 ions cm-2. Thereafter, the yields decreased immediately to almost zero and remained constant with the yield at zero until a dose of approximately 4 × 1016 ions cm-2 was reached. At larger doses, the yields increased again and reached a steady-state value of approximately 0.6. This development of the sputtering yield after the onset of ion bombardment is explained by an ion-induced modification of the photoresist that includes preferential sputtering of individual groups, argon ion implantation and the generation of voids. All these effects must be taken into account to assess line-edge-roughness on a photoresist subjected to highly energetic ion irradiation. [ABSTRACT FROM AUTHOR]

Al2O3 thin films, either amorphous or of varying degrees of crystallinity, were deposited by two-frequency radio-frequency magnetron sputtering. Film crystallinity was investigated by Fourier transform infrared spectroscopy and X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) was employed to determine the amount of Ar naturally trapped within the films during the deposition process. A clear correlation was found between the existence of crystalline phases, as determined by XRD, and a shift towards lower binding energy positions of the Ar2p core levels of embedded gas. The shift is due to differences in the local Al2O3 matrix (amorphous or crystalline) of the embedded gas, thus, providing an XPS fingerprint that can be used to qualitatively determine the presence or absence of crystalline phases in very thin films. [ABSTRACT FROM AUTHOR]

A time-resolved analysis of the emission of power impulse magnetron sputtering plasmas reveals inhomogeneities in the form of rotating spokes. The shape of these spokes depends on the target material in a characteristic manner; the peculiar shape of the emission profiles is explained by the localization of the sputtering process as being governed by Ar gas rarefaction and the local dynamics of secondary electrons generation. This general picture is able to explain the observed emission patterns for different target materials as presented. [ABSTRACT FROM PUBLISHER]

High-power pulsed magnetron sputtering (HPPMS) plasmas are pulsed discharges, where the plasma composition as well as the fluxes and energies of ions are changing during the pulse. The time resolved energy distribution for Ar1+ ions was measured and phase resolved optical emission spectroscopy for the Ar I line at 760 nm was done to get more insight in the transport properties of the plasma forming noble gas. These measurements were performed during HPPMS of titanium with argon at 0.5 Pa. The peak power density during the 50- \(\mu \) s pulses was 1.8 kW/cm \(^{2}\) . In this contribution, we demonstrate how time resolved mass spectrometry and Intensified Charge-Coupled Device, Intensified CCD cameras can be used to shed more light on energy and particle transport in HPPMS-plasmas. [ABSTRACT FROM PUBLISHER]

The article focuses on the European project BIODECON which studies the interaction of plasmas with bacteria, viruses, and pathogenic molecules. It mentions that the project depicts the noticeable use of identical plasma reactors at every participating laboratory in Germany, France and Italy. It notes that results of the study are significant in the case of plasma inactivation of prions. It is stated that understanding of fundamental mechanisms of plasma sterilisation is a vital step for its further development and final application in the medical industry.