Polycrystalline tungsten (W) has been irradiated with a low-energy (30–830eV) He+ beam at the W surface temperature of 523–1073K up to a fluence of 1.0×1025/m2. Measurements by non-destructive ...conductive atomic force microscopy show the existence of nanometer-sized interstitial loops in He+-implanted layer. The size and distribution of interstitial loops are significantly affected by He+ energy and fluence, and W surface temperature. The distribution of interstitial loops becomes orientated in one certain direction after being irradiated at a relatively high fluence or W surface temperature. The cascading slipping of W atoms along one certain dense-packed face has been proposed to explain the ordered arrangement of interstitial loops at elevated temperature. Analysis indicates that the continuous growth of unstable nanometer-sized interstitial loops can result in the surface exfoliation of W materials.
In this work PeakForce Kelvin Probe Force Microscopy (PF-KPFM) at ambient environment is used to characterize both oxidation states of copper (Cu) surfaces, cupric oxide CuO and cuprous oxide Cu2O, ...with high lateral resolution. Characteristic values of the Contact Potential Difference were obtained for the copper oxide states. By this means, PF-KPFM measurements enabled to distinguish between the different types of Cu oxide with nanometer resolution and to correlate the oxidation states to local topography features. It was even possible to identify single oxide grains on top of the Cu surface. As a result, PF-KPFM is able to address the needs for nanoscale characterization methods in semiconductor manufacturing or other related technologies where the local oxidation behavior of copper is a critical issue.
•PeakForce Kelvin Probe Force Microscopy is used to characterize the copper oxide type.•CuO and Cu2O can clearly be distinguished by the Contact Potential Difference value.•Topography and oxidation state are evaluated simultaneously at ambient conditions.•Local oxide grain structures can be characterized in the nanoscale.•CuO grains apparently merge and build up larger grains.
•We prepared CH3 Self-Assembled Monolayer (SAM) as protective coating on copper.•Temperature stability was analyzed by advanced scanning probe microscopy techniques.•100°C stress leads to a ...significant tunneling current rise and hydrophobicity drop.•At 150°C stress the degradation results in a state of decomposition of the SAM film.•High current spots and local hydrophobic variations can be detected in the nanoscale.
In this study, we used Self-Assembled Monolayer (SAM) with CH3 end-group molecules to protect copper surfaces from oxidation and investigated at nanometer scale the integrity and temperature stability of the protective film. The films were characterized by dynamic Chemical Force Microscopy (dCFM), Torsional Resonance Tunneling Atomic Force Microscopy (TR-TUNA) and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR).
We observed that temperature stress degraded local properties of our SAM films significantly, when compared to unstressed films. After temperature stress at 100°C, tunneling current increased and hydrophobicity decreased substantially. In combination with the ATR-FTIR results we assigned local high current spots and local hydrophobic variations to cuprous oxide (Cu2O). After temperature stress at 150°C, the measurements indicate a decomposition of the SAM film and a further oxidation of the copper surface. In addition, the results show that dynamic dCFM and TR-TUNA are appropriate tools to characterize SAM films structurally, chemically and electrically. Most important, in contrast to conventional contact mode Atomic Force Microscopy techniques, we did not observe any damage to the SAM film by dCFM and TR-TUNA measurements.
In this work, we report on the protective effect of platinum and carbon based films deposited onto Cu surfaces subject to pre-bonding temperature stress. The protection of Cu surfaces is an important ...and advantageous procedure to improve the reliability of Cu-Cu connections. The results were obtained from combined non-destructive Scanning Electron Microscopy (SEM) techniques and PeakForce Kelvin Probe Force Microscopy (PF-KPFM).
As an indicator of degradation, the oxidation of the Cu surface was used. It could be shown that a C layer provides a much better protective effect than a Pt layer. Besides very local sporadically distributed Cu oxide grains, a gradual degradation of the protective carbon film was not even observable at the nanoscale for a stress temperature of 200°C and layer thicknesses down to 3nm. In contrast, with a 10nm thick Pt film the Cu surface exhibits already at a stress temperature of 150°C locally grown Cu oxide grains. The introduced carbon coating passivation of Cu surfaces has the potential of being a key technique for a reliable Cu-Cu wire bonding.
•We investigated carbon (C) and platinum (Pt) layer as protective coating on copper.•Protective nanometer films were deposited by Ion beam sputtering.•Degradation up to 200°C stress is studied by combined scanning microscopy methods.•150°C stress leads to a significant degradation of the 10nm Pt coating layer.•A gradually degradation of the 3nm C coating was even not visible at the nanoscale.
Low-energy (20–520eV) hydrogen ion irradiations were performed at W surface temperature of 373–1073K and a fluence ranging from 5.0×1023 to 1.0×1025/m2. Conductive atomic force microscopy (CAFM) as a ...nondestructive analytical technique was successfully used to detect irradiation-induced defects in polycrystalline W. The size and density of these nanometer-sized defects were strongly dependent on the fluence of hydrogen ions. Both ion energy (E) and temperature (T) play a crucial role in determining the ordering of nanometer-sized defects. Ordered arrangements were formed at relatively high E and T. This can be attributed to the stress-driven ripple effect of defect growth at crystal grains, resulting in the movement of W lattice along one certain crystal planes.
For advanced atomic force microscopy (AFM) investigation of chemical surface modifications or very soft organic sample surfaces, the AFM probe tip needs to be operated in a liquid environment because ...any attractive or repulsive forces influenced by the measurement environment could obscure molecular forces. Due to fluid properties, the mechanical behavior of the AFM cantilever is influenced by the hydrodynamic drag force due to viscous friction with the liquid. This study provides a numerical model based on computational fluid dynamics (CFD) and investigates the hydrodynamic drag forces for different cantilever geometries and varying fluid conditions for Peakforce Tapping (PFT) in liquids. The developed model was verified by comparing the predicted values with published results of other researchers and the findings confirmed that drag force dependence on tip speed is essentially linear in nature. We observed that triangular cantilever geometry provides significant lower drag forces than rectangular geometry and that short cantilever offers reduced flow resistance. The influence of different liquids such as ultrapure water or an ethanol-water mixture as well as a temperature induced variation of the drag force could be demonstrated. The acting forces are lowest in ultrapure water, whereas with increasing ethanol concentrations the drag forces increase.
Comprehensive and developed by a panel of leading international experts in the field, Tinnitus: Diagnosis and Treatment provides a multidisciplinary overview of the diagnosis and management of a ...widespread and troubling disorder.
Artificial Intelligence (incl. Robotics); Data Mining and Knowledge Discovery; Information Systems Applications (incl. Internet); User Interfaces and Human Computer Interaction; Pattern Recognition; ...Computer Communication Networks
Pleural effusion is common in routine medical practice and can be due to many different underlying diseases. Precise differential diagnostic categorization is essential, as the treatment and ...prognosis of pleural effusion largely depend on its cause.
This review is based on pertinent publications retrieved by a selective search in PubMed and on the authors' personal experience.
The most common causes of pleural effusion are congestive heart failure, cancer, pneumonia, and pulmonary embolism. Pleural fluid puncture (pleural tap) enables the differentiation of a transudate from an exudate, which remains, at present, the foundation of the further diagnostic work-up. When a pleural effusion arises in the setting of pneumonia, the potential devel- opment of an empyema must not be overlooked. Lung cancer is the most common cause of malignant pleural effusion, followed by breast cancer. Alongside the treatment of the underlying disease, the specific treatment of pleural effusion ranges from pleurodesis, to thoracoscopy and video-assisted thoracoscopy (with early consultation of a thoracic surgeon), to the placement of a permanently indwelling pleural catheter.
The proper treatment of pleural effusion can be determined only after meticulous differential diagnosis. The range of therapeutic options has recently become much wider. More data can be expected in the near future concerning diagnostic test- ing for the etiology of the effusion, better pleurodetic agents, the development of interventional techniques, and the genetic background of the affected patients.
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