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Hydrogen outgassing from a metal surface and a coated metal surface was visualized by two-dimensional mapping of hydrogen ions desorbed upon scanning electron beam irradiation. The samples used were stainless steel covered with a dense chromium oxide layer, and a reference surface of stainless steel. The coating layer was made by using the segregation phenomenon of the metal. Outgassing of hydrogen was detected from the holelike defects on the treated surface. However, hydrogen was not released from all the holelike defects seen in the SEM image. The outgassing positions were positions without chromium, but not all areas without chromium and/or oxygen coincided with outgassing positions.

The solid reaction of lithium hydride and lithium hydroxide in lithium hydride pellet is first directly observed at normal ambient condition after 4 years storage. Layer-by-layer XPS results show that LiOH hydrolysis layer quickly forms on the LiH surface, LiOH reacts with bulk LiH to form Li2O and H2. Due to the great H2 outgassing after long time conservation, bubbling problem actually exists during the practical long-time preserving period. Using CO2 as pre-treatment gas during the LiH sample preparation process is a feasible way to prevent LiH sample from bubbling after long storage period. Moreover, Li2CO3 shows possible delay effect on the solid reaction of LiOH with LiH in this work, thus preserving LiH sample in CO2 containing atmosphere might also be an prospective way to protect the sample from further corrosion.

Hydrogen embrittlement can cause catastrophic failure of high strength alloys, yet determining localised hydrogen in the microstructure is analytically challenging. NanoSIMS is one of the few techniques that can map hydrogen and deuterium in metal samples at microstructurally relevant length scales. Therefore it is essential to understand the artefacts and determine the optimum methodology for its reliable detection. An experimental methodology/protocol for NanoSIMS analysis of deuterium (as a proxy for hydrogen) has been established uncovering unreported artefacts and a new approach is presented to minimise these artefacts in mapping hydrogen and deuterium in alloys. This method was used to map deuterium distributions in electrochemically charged austenitic stainless steel and precipitation hardened nickel-based alloys. Residual deuterium contamination was detected in the analysis chamber as a result of deuterium outgassing from the samples, and the impact of this deuterium contamination was assessed by a series of NanoSIMS experiments. A new analysis protocol was developed that involves mapping deuterium in the passive oxide layer thus mitigating beam damage effects that may prevent the detection of localised deuterium signals when the surface is highly deuterated.

International audience; Li4Ti5O12 (LTO) based batteries have severe gassing behavior during charge/discharge and storage process, due to interfacial reactions between active material and electrolyte solution. In the same time, the electronic and ionic conductivity of pristine LTO is very poor and induces the use of nanoparticles which increase the outgassing phenomena. The coating of LTO particles could be a solution. For this the LTO spinel particles are modified with ionic conductor Li3PO4 coating using a spray-drying method. For the first time a homogeneous thin dense layer phosphate based conductor is obtained without nanoparticles, as a thin film material. It is so possible to study the influence of ionic conductor deposited on the negative electrode material on performances by the controlled layer thickness. This coating was characterized by XRD, SEM, XPS and TEM. The electrochemical performance of Li3PO4 coated Li4Ti5O12 is improved at high C-rate by the surface modification (improvement of 30 mAh g(-1) at 5 C-rate compared to pristine LTO for 5 nm of coating), inducing by a modification of surface energy. An optimum coating thickness was studied. This type of coating allows a significant decrease of outgassing phenomena due the conformal coating and opens the way to a great number of studies and new technologies. (C) 2016 Elsevier B.V. All rights reserved.

In order to systematically evaluate the surface influence on aluminum alloy’s outgassing characteristics, 10-hour’s outgassing experiments of 5A06 and 2A12 with different roughness and cleanness were firstly tested and compared. Then measurements of the outgassing rate and desorption gas components were performed on 7075 and 6061 with and without anodic alumina coatings. Furthermore, the substrate microstructures, surface micro-morphologies and element compositions of anodized aluminum alloys were analyzed emphatically. The results revealed that the surface roughness, cleanliness and oxide film all have influence on the outgassing behavior of aluminum materials. It is observed that the rougher the surface is, the more gases are released. It is pointed out that the outgassing rate of aluminum alloy with anodizing is 1–2 orders of magnitude higher than that without, which is mainly reflected by the significant increase in water vapor and the emerging of hydrocarbons. Combining with a detailed material analysis, it is concluded that the outgassed water of anodic alumina alloy is more originated from its surface hydrated products formed during the sealing process, while the emitted hydrocarbons are largely related to the organic maters used in the dyeing procedure.

In this work we report the surface morphology of amorphous germanium (a-Ge) thin films (140 nm thickness) following thermal outgassing of SiO2/Si substrates. The thermal outgassing was performed by annealing the samples in air at different temperatures from 400 to 900 °C. Annealing at 400 °C in slow (2 °C/min) and fast (10 °C/min) modes promotes the formation of bubbles on the surface. A cross sectional view by transmission electron microscope taken of the sample slow annealed at 400 °C reveals traces of gas species embedded in the a-Ge film, allowing us to propose a possible mechanism for the formation of the bubbles. The calculated internal pressure and number of gas molecules for this sample are 30 MPa and 38 × 108, respectively. Over an area of 22 × 10−3 cm2 the density of bubbles obtained at slow annealing (9 × 103 cm−2) is smaller than that at rapid annealing (6.4 × 104 cm−2), indicating that the amount of liberated gas in both cases is only a fraction of the total gas contained in the substrate. After increasing the annealing temperature in the slow mode, bubbles of different diameters (from tens of nanometers up to tens of micrometers) randomly distribute over the Ge film and they grow with temperature. Vertical diffusion of the outgas species through the film dominates the annealing temperature interval 400–600 °C, whereas coalescence of bubbles caused by lateral diffusion is detected after annealing at 700 °C. The bubbles explode after annealing the samples at 800 °C. Annealing at higher temperatures, such as 900 °C, leads to surface migration of the film to the exploded bubbles and eventually forming islands of polycrystalline GeO2.

This paper addresses a hydrogen outgassing mechanism in titanium materials with extremely low outgassing property by investigating the distribution of hydrogen atoms concentration in depth below the surface, and the activation energy for desorption of dissolved hydrogen atoms into the boundary region between the surface oxide layer and the bulk titanium and that of adsorbed hydrogen atoms on the surface. The distribution of hydrogen atoms concentration in depth below the surface was analyzed by a time-of-flight secondary ion mass spectrometry (TOF-SIMS). The activation energy for desorption of dissolved hydrogen atoms was estimated by the thermal desorption spectroscopy (TDS) measurement with various heating rates. The activation energy for desorption of adsorbed hydrogen atoms was estimated by the temperature dependence of the outgassing rate in titanium material. In the titanium material, hydrogen atoms show maximum concentration at the boundary between the surface oxide layer and the bulk titanium. Concentration of hydrogen atoms decreases rapidly at the surface oxide layer, while it decreases slowly in the deep region below the surface layer–bulk boundary by the vacuum evacuation without/with the baking process. The activation energy for desorption of 1.02 eV of dissolved hydrogen atoms into the surface layer–bulk boundary is about three times as large as that of 0.38 eV of the adsorbed hydrogen atoms on the surface. These results suggest that the hydrogen outgassing mechanism in the titanium material is composed the follows processes, i.e. the slow hydrogen atoms diffusion at the surface layer–bulk boundary, quick hydrogen atoms diffusion at the surface oxide layer and rapid desorption of adsorbed hydrogen atoms on the surface. This outgassing mechanism gives very low hydrogen concentration near the surface, which results in the extremely low outgassing rate in titanium materials.

The adhesion behavior of di-n-butyl phthalate (DBP) onto different substrates (quartz, glass, and silicon) used as wafer surfaces was studied by using an in situ UV spectrophotometric technique. The results from the closed cell experiments revealed that greatest extent of DBP adhesion occurred on the quartz chip (0.154 μg cm−2), followed in the order by the glass (0.054 μg cm−2) and silicon (0.039 μg cm−2). By means of the in situ spectrophotometric observation, application of an electrical field at 290 V cm−1 in the cell proved to be effective in inducing charging of DBP aerosols, which were consequently attracted towards the electrodes. This method can be applied to wafer storage and transport equipments to prevent wafer contamination from material outgassing representative by DBP.

Lithography at 157 nm using F2 laser is the next step after 193 nm for ULSI fabrication with dimensions below 50 nm. However, there are certain issues to be addressed before the acceptance of the technology by the industry. The most important are: (1) design of resists with low absorption and outgassing at 157 nm, (2) improved line edge roughness and resolution and (3) defect-free resist surface following illumination at 157 nm. In this communication it has been confirmed theoretically and experimentally that outgassing of resists at 157 nm is an intrinsic molecular property and does not depend on the laser parameters. Based on a theoretical model, a new method for measuring outgassing of resists has been developed by measuring the thickness loss, following illumination at 157 nm, using vacuum ultraviolet absorption spectroscopy and atomic force microscopy.

The acceleration gradient of an electron linac is limited by rf breakdown in its accelerating structure. We applied an imaging spectrograph system to study the mechanism of rf breakdown phenomena in accelerating rf structures. Excited gases released from the surface emit light during rf breakdown with the type of gases dependent upon surface treatments and rinsing methods. To study rf breakdown, we used 2-m-long accelerating structures and investigated the effects of a high-pressure ultrapure water rinsing (HPR) treatment applied to these rf structures. We performed experiments to study the gases released from the surface of rf structures with quadrupole mass spectroscopy and imaging spectrography of atomic lines. As a result, just after rf breakdown, we could observe instantly increasing signals at mass numbers 2 (H2), 28 (CO), and 44 (CO2), but not 18 (H2O). We also conducted spectral imaging of the light emissions from the atoms and ions in a vacuum excited through rf breakdown. Using an accelerating structure without HPR treatment, we observed atomic lines at 511 nm (Cu I), 622 nm (Cu II), and 711 nm (C I). With HPR treatment, the atomic lines were observed at 395 nm (O I), 459 nm (O II), 511 nm (Cu I), 538 nm (C I), 570 nm (Cu I), 578 nm (Cu I), 656 nm (H: Balmer alpha), and 740 nm (Cu II). In an additional surface analysis, we found carbon as the most dominant element, with the exception of copper, on the blackened surface of the rf-conditioned accelerating structure without HPR treatment. Based on these experiments, we concluded that some components of the plasma can affect a copper surface. We also have provided a phenomenological review of our experimental results and a simple explanation of rf conditioning with rf breakdown.

We have studied the effect of residual gas on the Mo and diamond-covered Mo field emitters. When the pressure increased by outgassing of the chamber, the emission current increased. The residual gas and thermal desorption analysis indicated that the hydrogen adsorption on the emitter was the reason for the increased current. The emission from each tip was examined using an aperture lens to magnify the electron beam. The gas–emitter interaction changed the number of tips that were emitting as well as the emission from the individual tip. When the tips were coated with nano-diamond particles, the pressure dependence was reduced significantly.

Using H+- and He+-ions in the energy range between 100 keV and 10 MeV, the effects of irradiation on polymethylmethacrylate (PMMA) were extensively studied. The surface shrinking phenomenon due to outgassing and the diffusion of the volatile scission products caused by the irradiation process have been investigated as a function of ion energy, ion fluence, dose rate and thermal treatment after the irradiation. Diffusion constants, mean diffusion path lengths and activation energies have been deduced from the shrinking dependency on the temperature. The influence of the ion fluence, the dose rate distinguished in current density and scan density and the particle energy is discussed. With respect to applications in deep ion beam lithography (DIBL) the results lead to the conclusion that one should prefer a rather dispersed instead of a sharply collimated beam in order to prevent an abrupt rupture during the irradiation. On the other hand, long irradiation times should be avoided to prevent inaccuracies with respect to the depth of the microstructures due to shrinking of the surface during irradiation.

The extreme high vacuum integrated process has been developed in order to transfer substrates among vacuum chambers without any contamination on the ultra clean surface. The integrated process has five main line chambers, six sidetrack chambers, connector chambers and six vacuum instrument chambers for surface analyses and film preparation. Magnetic levitation transports are installed into the line chambers because they have no sliding part to generate dust particles as well as outgassing which may much damage the ultra clean substrate surfaces and environment. The levitation transports can transfer a substrate among connected six chambers in the pressure change of less than 10−10 Pa. Auger analysis shows that surface of a Cu coated steel substrate prepared in the film preparation chamber can be kept clean without oxygen nor carbonate during the transportation from the film preparation chamber to the auger analysis chamber.

Water adsorption–desorption on aluminum surface studied at the Synchrotron Radiation Research Center (SRRC) is described. Both the thermal desorption and the photon stimulated desorption were studied. It was observed that the outgassing behavior of water is quite different from that of the other gases. Experimental results showed that the processes of venting, evacuation and vacuum treatment are sensitive to the water desorption behavior.

Chamber walls, subjected to “in situ” baking, sometimes show a pumping function for a high vacuum, while a high-vacuum pump sometimes shows outgassing in an ultrahigh vacuum. Such functions of the system elements can be represented by the internal pressures P X . All the system elements, such as chamber walls, pumps, and pin holes through a pipe wall, can be replaced by a pressure generator with the internal pressure P X and the internal flow impedance R X in the equivalent vacuum circuit. The internal pressure P X of the chamber wall varies depending on the wall history under high vacuum. The equivalent vacuum circuit composed of many characteristic values ( P X , R X ) and flow impedances R can represent the gas flows in the original high-vacuum system.

We have successfully used the Spindt field emitter array (FEA) in the pressure measurements in ultrahigh vacuum (UHV) and extremely high vacuum (XHV). For applying the FEA to pressure measurements, we have made evaluation tests, focusing on gas exposure and outgassing characteristics. The cold cathode hardly influenced the vacuum conditions, compared to a hot-filament cathode.

Adsorption of boric acid trimethyl ester (BATE) on high-surface-area silica has been studied by FT-IR spectroscopy. It is found that surface hydroxyls remaining after outgassing at high temperatures act as weak basic sites for BATE adsorption. Coordinate interaction of BATE with isolated hydroxyls dominates the adsorption and induces two splitting B–O vibrational bands at 1375 and 1345 cm −1 . In addition, a small amount of BATE reacts with hydrogen-bonded hydroxyls and strained oxygen generated after high-temperature dehydroxylation.

Vacuum characteristic of pure Ti surface modified by such different methods as buffing (BP), chemical (CP) and mechano-chemical (MCP) polishing was compared by using thermal desorption spectroscopy. A characterization of the modified surface was made with scanning electron microscopy to measure electron channelling pattern and profilometry roughness. We report a comparison of thermal desorption aspects in correlating with the modified surface. An outgassing measurement, using the through-put chamber of chemical polished, showed desorbed gasses dominated by not only H2O but also CO(N2) and H2.

This paper aims at finding the most proper surface treatment method to obtain the extreme low outgassing from boron nitride (BN) precipitated stainless steel. A correlation between surface treatments and precipitation aspects of hexagonal boron nitride (h-BN) on an austenitic stainless steel was studied. Precipitation aspects of BN on a polished surface with different method were observed using scanning electron microscopy (SEM). Surface treatments such as buff polishing (BP), electro polishing (EP), electrochemical buffing (ECB) and float polishing (FP) were employed. It was found that electron channeling pattern (ECP) showed no evidence of formation of the modified layer near the surface of both FP and EP treatments. On these surfaces, BN was precipitated almost uniformly and covered the whole surface, while BN precipitated not uniformly but spotty on the other surfaces (BP and ECB). As the thickness of the BN layer increased, strong oriented triangular crystalline BN was observed on the FP surface. The float polishing may be a candidate of the most proper surface treatment for BN precipitation.