TY - CHAP A1 - Melekhov, Evgeny A1 - Abb, Valerius A1 - Lechner, Alfred A1 - Kammler, Martin ED - Ivanov, Artem ED - Bicker, Marc ED - Patzelt, Peter T1 - Development of a glass-fiber-based spectrometer for the determination of drug residues in groundwater T2 - Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020 "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung" N2 - Within the scope of this project, a portable measuring device has been developed which enables a cost-effective analysis of organic substances from ppm to sub-ppm range, such as drug residues in groundwater. The measurement is carried out by means of a surface-enhanced Raman scattering effect (SERS effect) and an exchangeable sensor head. The sensor head used is a nanostructured optical glass fiber glued into a fiber cannula. The tip of the fiber has been processed to act as a SERS cell. The fiber cannula is connected to a freely movable patch cable by using an adapter. Para-thiocresol is used to characterize the SERS cells. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:860-opus4-2174 SN - 978-3-9818439-4-1 SP - 101 EP - 109 ER - TY - GEN A1 - Melekhov, Evgeny A1 - Abb, Valerius A1 - Weidauer, Tobias A1 - Kammler, Martin A1 - Lechner, Alfred T1 - Tunable Nanopillars as Surface Enhanced Raman Scattering (SERS) Active Structure for Optical Quartz Glass Fiber T2 - SMSI 2021 - Sensors and Instrumentation N2 - In this work, a simple cost effective method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas on a tip of an optical quartz glass fiber is described. The structures are prepared using lithography-less dry etching. Gold nanoparticles are used as an etching mask using a thin metal-film thermal dewetting technique. The structures are applied as sensor for label-free analysis of organic substances in ppb range, such as drug residues in groundwater. The measurements are carried out by means of a Surface-enhanced Raman scattering (SERS) effect, an exchangeable sensor head, and a portable Raman device. This method allows in situ applications. Parathiocresol is used as a model substance to characterize the SERS cells. For metallization, gold and silver are compared. Reproducible SERS enhancement factors up to 10 7 are evaluated. Y1 - 2021 SN - 978-3-9819376-4-0 U6 - https://doi.org/10.5162/SMSI2021/B8.2 SP - 153 EP - 154 PB - AMA Association for Sensors and Measurement ER - TY - INPR A1 - Menzel, Andreas A1 - Yeh, Wang-Chi Vincent A1 - Kammler, Martin A1 - Hupalo, Myron A1 - Conrad, E. H. A1 - Tringides, Michael C. T1 - Measurements of the kinetic barriers controlling the formation of the uniform height islands in Pb/Si(111) N2 - As demonstrated with SPA-LEED and STM uniform height islands of preferred thickness form during the growth of Pb on Si(111). The islands form at temperatures T<250K and for fluxes F 1/60ML/sec which requires fast kinetics and balance between several atomic processes: diffusion towards the islands , diffusion to higher layers and preference for the atoms to remain on top of the preferred height islands. We have carried out SPA-LEED experiments to measure the barriers of the processes: we prepare an initial predominantly 5-step island height distribution and we deposit an additional 0.5ML Pb at different growth temperatures Tg to determine the transition to the next preferred height of 7-step islands (i.e. 2-step islands on top of the 5-step islands) with Spot Profile Analysis(SPA-LEED). We observe that 7-step island formation is possible above a minimum temperature Tg*=175K which indicates that the transfer of atoms from the surrounding region to the top of the islands is the main controlling process. Y1 - 2002 UR - https://www.researchgate.net/publication/259264144_Measurements_of_the_kinetic_barriers_controlling_the_formation_of_the_uniform_height_islands_in_PbSi111 ER - TY - INPR A1 - Cavalleri, Andrea A1 - Siders, Craig A1 - Toth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - von der Linde, Dietrich A1 - Kammler, Martin A1 - Horn- von Hoegen, Michael T1 - Measurement of harmonic and anharmonic semi-conductor-lattice dynamics with ultrafast x-ray diffraction N2 - Many fundamental processes in solids, such as heat transport and phase transitions involve atomic movement on ultrafast time-scales, but cannot be directly measured with visible light. Using ultrafast x-ray diffraction, atomic motion can be measured on its natural time-scale. Photo-excitation of bulk and layered semiconductors was achieved with 800-nm wavelength femtosecond laser pulses. Optical excitation triggers a chain of relaxation processes, causing rapid lattice heating, generation and propagation of stress/strain waves into the bulk and eventual anharmonic decay of coherent acoustic phonons into the thermal bath of the solid. While the first steps of carrier relaxation, excitation and decay of Raman-active optical phonons have been in the past characterized optically at surfaces, the bulk acoustic dynamics at longer times has not. We measure length scales of lattice excitation, thereby detecting ultrafast heat diffusion via fast electrons, coherent acoustic pulse propagation into the bulk or across buried interfaces and anharmonic damping of non-equilibrium acoustic phonons. The measurement is performed with sensitivity on lattice spacing of 10 femtometers (i.e., 3 nuclear diameters). Y1 - 2000 UR - https://www.researchgate.net/publication/252175863_Measurement_of_harmonic_and_anharmonic_semi-conductor-lattice_dynamics_with_ultrafast_x-ray_diffraction ER - TY - INPR A1 - Siders, Craig A1 - Cavalleri, Andrea A1 - Toth, Csaba A1 - Squier Jeff A., A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - von der Linde, Dietrich A1 - Kammler, Martin A1 - Horn- von Hoegen, Michael T1 - Ultrafast Nonthermal Melting of Femtosecond-laser-irradiated Germanium Measured by Ultrafast X-ray Diffraction N2 - Many fundamental processes in nature, such as chemical reactions and phase transitions involve rearrangement of the constituent atoms. Such changes cannot be directly measured with visible light and occur transiently on time-scales comparable with the natural oscillation periods of atoms (femtoseconds to picoseconds). We present experiments on Ge-111 films irradiated with 100-fs 800-nm light pulses and probed by a time-delayed sub-ps x-ray pulse at 8 keV. After excitation of a dense electron-hole plasma within the 160-nm film, the ultrafast pathway of lattice disordering is measured as a function laser fluence. For close-to-threshold irradiation, inhomogeneous thermal melting, occurring via surface nucleation of the liquid phase and growth into the bulk determines the dynamics of the solid-to-liquid phase transition. For excitation at about twice the melting threshold, a nonthermal pathway, starting from a highly excited cold solid and relaxing into a hot liquid causes ultrafast melting. At long time delays, nearly perfect recrystallization of a (111) crystal is observed. Y1 - 2000 UR - https://www.researchgate.net/publication/252159566_Ultrafast_Nonthermal_Melting_of_Femtosecond-laser-irradiated_Germanium_Measured_by_Ultrafast_X-ray_Diffraction ER - TY - JOUR A1 - Chee, See Wee A1 - Kammler, Martin A1 - Graham, Jeremy A1 - Gignac, Lynne A1 - Reuter, Mark C. A1 - Hull, Robert A1 - Ross, Frances M. T1 - Directed Self-Assembly of Ge Quantum Dots Using Focused Si2+ Ion Beam Patterning JF - scientific reports N2 - We show that templating a Si surface with a focused beam of Si2+ or Si+ ions can create suitable nucleation sites for the subsequent growth of self-assembled Ge quantum dots by chemical vapor deposition. To determine the mechanism of patterning we use atomic force microscopy to show that, similar to Ga+ patterning, the formation of a surface pit is required to enable control over Ge quantum dot locations. We find that relatively high implantation doses are required to achieve patterning, and these doses lead to amorphization of the substrate. We assess the degree to which the substrate crystallinity can be recovered by subsequent processing. Using in situ transmission electron microscopy heating experiments we find that recrystallization is possible at the growth temperature of the Ge quantum dots, but defects remain that follow the pattern of the initial implantation. We discuss the formation mechanism of the defects and the benefits of using Si ions for patterning both defects and quantum dots on Si substrates. KW - ARRAYS KW - AU KW - DAMAGE KW - GROWTH KW - IMPLANTATION KW - NUCLEATION KW - RECOVERY KW - silicon KW - TECHNOLOGY Y1 - 2018 U6 - https://doi.org/10.1038/s41598-018-27512-z VL - 8 SP - 1 EP - 10 PB - Nature ER - TY - CHAP A1 - Blahníková, Barbora A1 - Müller, D. A1 - Waas, M. A1 - Lechner, Alfred T1 - Multilyzer - microfluidic online measuring system for the analysis of environmentally relevant substances T2 - AMA Conferences 2017 : Proceedings : SENSOR 2017 / Nürnberg 2017-05-30 - 2017-06-01 Y1 - 2017 SN - 978-3-9816876-4-4 U6 - https://doi.org/10.5162/sensor2017/P5.2 SP - 696 EP - 699 PB - AMA Service GmbH CY - Wunstorf ER - TY - JOUR A1 - Melekhov, Evgeny A1 - Penn, Tatjana A1 - Weidauer, Tobias A1 - Abb, Valerius A1 - Kammler, Martin A1 - Lechner, Alfred T1 - Tunable nanopillar array on a quartz-fiber tip for surface enhanced Raman scattering (SERS) detection JF - tm - Technisches Messen N2 - In this work, a simple two-step method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas directly on the tip of an optical quartz glass fiber is described. The structures are prepared by using dry etching of the fiber tip. For the etching process, gold nanoparticles fabricated by thermal dewetting technique were used as template. The structures are applied as sensors for label-free analysis of organic substances in ppb range, such as drug residues in liquid solutions. The measurements are carried out by a portable Raman device with an exchangeable sensor head utilizing the SERS-effect. This method allows in situ applications. In order to characterize the SERS cells, para-thiocresol and diclofenac sodium are used as model substances. For optimization of the substrate performance, different thicknesses of the dewetting-layer (6, 9, 12 nm), different etching times for formation of the pillars (6, 8, 10 and 12 min), and different thicknesses of SERS-metallization (25, 50, 75 nm) of gold and silver are compared. In order to show the applicability of the structure on the tip of a fiber, measurements from the upper side and from the underside of the substrate on quartz plates are compared. Reproducible SERS enhancement factors up to 10 7 {10^{7}} were achieved. N2 - In dieser Arbeit wird eine zweistufige Methode beschrieben, um einstellbare selbstorganisierte dreidimensionale SERS-aktive Nanostrukturen in Form von Nanosäulen auf der Spitze einer optischen Quarzglasfaser herzustellen. Die Strukturen werden durch trockenchemisches Ätzen der Faserspitze erzeugt. Für den Ätzprozess werden als Maske Goldnanopartikel verwendet, die mittels Thermal Dewetting hergestellt werden. Der Sensor wird für eine markierungsfreie Analyse von organischen Substanzen, wie bspw. Medikamentenrückstände in wässrigen Lösungen, im ppb-Bereich eingesetzt. Die Messungen werden mit einem tragbaren Raman-Gerät mit einem austauschbaren Sensorkopf durchgeführt. Um die SERS-Zellen zu charakterisieren, werden para-Thiocresol und Diclofenac-Natrium als Modellsubstanzen verwendet. Zur Optimierung der Substratleistung werden unterschiedliche Dicken der Dewettinglayer (6, 9, 12 nm), unterschiedliche Ätzzeiten der Nanosäulen (6, 8, 10 und 12 min) und unterschiedliche Schichtdicken der SERS-Metallisierung (25, 50, 75 nm) von Gold und Silber verglichen. Um die Anwendbarkeit der Struktur an der Spitze einer Faser zu zeigen, werden Messungen von der Oberseite und von der Rückseite des Substrats in Form eines Quarzglasplatten verglichen. Diese Struktur liefert einen reproduzierbaren Verstärkungsfaktor von bis zu 107. T2 - Einstellbare Nanosäulenanordnung auf der Spitze einer Quarzglasfaser für oberflächenverstärkte Raman-Spektroskopie (SERS) Y1 - 2022 U6 - https://doi.org/10.1515/teme-2021-0093 VL - 89 IS - 1 SP - 70 EP - 81 PB - de Gruyter ER - TY - JOUR A1 - Kammler, Martin A1 - Chidambarrao, D. A1 - Schwarz, K. W. A1 - Black, C. T. A1 - Ross, Frances M. T1 - Controlled nucleation of dislocations by a spatially localized stress field JF - Applied Physics Letters N2 - We analyze the nucleation of dislocations in silicon at spatially localized stress fields generated by silicon nitride pads having a high intrinsic stress. The nucleation and final configuration of the dislocations were studied using hot-stage transmission electron microscopy and were compared with dislocation simulations based on calculations of the stress fields around the pads. We find that the simulated configurations match well with the experimental data, and we show that the dislocation configuration can be controlled by the pad size. Y1 - 2005 U6 - https://doi.org/10.1063/1.2061862 VL - 87 IS - 13 PB - AIP ER - TY - JOUR A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael T1 - Transition in growth mode by competing strain relaxation mechanisms BT - surfactant mediated epitaxy of SiGe alloys on Si JF - Applied Physics Letters N2 - Surfactant mediated epitaxy of Si(1−x)Gex alloys on Si(111) can, besides technological importance, clarify the influence of the lattice mismatch during surfactant mediated heteroepitaxial growth. For low Ge concentration we find an immediate layer-by-layer growth, whereas at high Ge concentration a roughening transition followed by relaxation of the lattice mismatch in a periodic dislocation network is preferred. This behavior can be explained by comparing the dislocation nucleation rate on a smooth surface with the island nucleation rate on a pseudomorphic film. Y1 - 2004 U6 - https://doi.org/10.1063/1.1803914 VL - 85 IS - 15 SP - 3056 EP - 3058 PB - American Institute of Physics ER - TY - JOUR A1 - Chee, See Wee A1 - Kammler, Martin A1 - Balasubramanian, Prabhu A1 - Reuter, Mark C. A1 - Hull, Robert A1 - Ross, Frances M. T1 - Microstructural changes in silicon induced by patterning with focused ion beams of Ga, Si and Au JF - Ultramicroscopy N2 - We use focused beams of Ga(+), Au(+) and Si(++) ions to induce local microstructural changes in single crystal silicon. The ions were delivered as single spot pulses into thin Si membranes that could subsequently be imaged and annealed in situ in a transmission electron microscope. For each ion, the focused ion beam implantation created an array of amorphous regions in the crystalline membrane. Annealing causes solid phase epitaxial regrowth to take place, but we show that the resulting microstructure depends on the ion species. For Ga(+) and Au(+), precipitates remain after recrystallization, while for Si(++), dislocation loops form around the periphery of each implanted spot. We attribute these loops to defects formed during solid phase epitaxial regrowth, with controlled placement of the loops possible. KW - dislocation engineering KW - focused ion beam KW - In situ electron microscopy KW - solid phase epitaxial regrowth Y1 - 2013 U6 - https://doi.org/10.1016/j.ultramic.2012.07.004 VL - 127 SP - 126 EP - 131 PB - Elsevier ER - TY - CHAP A1 - Blahníková, Barbora A1 - Müller, D. A1 - Waas, M. A1 - Lechner, Alfred T1 - Multilyzer - Mikrofluidisches Echtzeitmesssystem für die Analyse umweltrelevanter Substanzen T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München N2 - Die übermäßige Verwendung von stickstoffbasierten Düngemitteln in der Landwirtschaft stellt eine Gefährdung für die Umwelt und Lebewesen dar. So ist die Analyse von Boden- und Grundwasser zu einem wesentlichen Bestandteil der Nachhaltigkeit und der ökologischen Erhaltung geworden. Dafür bietet der Multilyzer eine passende Lösung. Der Multilyzer ist ein mikrofluidisches Analysesystem zur Bestimmung niedrigster Konzentrationen von Nitrat, Nitrit und Ammonium, die alle wesentliche Bestandteile des Stickstoffkreislaufs sind. Welche bei Übermäßiger Aufnahme im Körper krebserregend wirken und den Sauerstofftransport im Blutkreislauf stören. Der Aufbau ist eine Kombination aus Absorptions- und Fluoreszenzspektroskopie. Der Betrieb mit einer 12 Volt Batterie ermöglicht die Verwendung des Multilyzer-Systems zur Online-Messung im Feld. Somit können sehr kurze Analysezeiten realisiert und der Einfluss von Umwandlungs- bzw. Abbauprozessen vermieden werden. Das gesamte Messsystem wird im Kompetenzzentrum Nanochem an der OTH Regensburg entwickelt, inklusive Fertigungstechnologien, Software- und Hardwaresteuerung. N2 - Excessive use of nitrogen based fertilizers in agriculture represents an environmental hazard. Thus, analysis of soil water and groundwater has become an essential part of sustainability and ecological preservation. On this account, the Multilyzer provides a suitable solution. The Multilyzer is a microfluidic measuring system for the determination of lowest concentrations of nitrate, nitrite and ammonium, which are essential components of the nitrogen cycle. The measurement combines the principles of absorption and fluorescence spectroscopy. As a transportable unit, online measurements can be carried out using a 12 Volts battery power supply. Consequently, the influence of conversion and degradation processes can be avoided. The complete device is developed at the Centre of Excellence Nanochem at OTH Regensburg including fabrication technologies, software and hardware control. T2 - Multilyzer - Microfluidic Online Measuring System for the Analysis of Environmentally Relevant Substances KW - Absorptionsspektroskopie KW - Ammonium KW - Analysensystem KW - Blutkreislauf KW - Bodenwasser KW - Düngemittel KW - Echtzeitsystem KW - Fluoreszenzspektroskopie KW - Messgerät KW - Messsystem KW - Mikrofluidik KW - Nachhaltigkeit KW - Nitrat KW - Nitrit KW - Online-Messung KW - Programmsteuerung KW - Stickstoff Y1 - 2017 SN - 978-3-8007-4491-6 SP - 382 EP - 385 PB - VDE-Verlag CY - München ER - TY - CHAP A1 - Betz, Michael A. A1 - Lechner, Alfred T1 - Sprayganik - Spraytool für organische Halbleiter T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München N2 - Sprühbeschichtung stellt einen kostengünstigen und materialeffizienten aber komplexen Prozess dar. Um diese Vorteile für die Abscheidung teurer organischer Halbleiter zu nutzen, wurde ein Sprühbeschichter entwickelt, der neueste Anforderungen an den Prozess erfüllt. Zudem konnten selbstansaugende Mikrosprühdüsen mikrotechnologisch in Silizium realisiert werden, welche bereits eine bis zu vierfache Materialeffizienz im Vergleich zu herkömmlichen airbrush-Düsen nachweisen konnten. Die neueste Düsengeneration zeigt nun eine weiter verbesserte Zerstäubung, was bei gesprühten OPDs zu einer reduzierten Dunkelstromdichte von 9,1×10-6 mA·cm-2 (-5 V) und erhöhten externen Quanteneffizienz von 78,5% (530 nm, -5 V) führt. N2 - Generally, spray coating is a cheap and material efficient but complex process. To exploit those advantages for deposition of expensive organic semiconductors, we developed a spray coater to fulfil latest requirements. Furthermore, it was possible to realize venturi micro nozzles that already showed up to 4-fold material efficiency when compared to conventional airbrush-nozzles. The latest nozzle layout shows an even better atomization resulting in photodiodes with a reduced dark current density of 9,1×10-6 mA·cm-2 (-5 V) and increased external quantum efficiency of 78,5% (530 nm, -5 V). KW - Dunkelstrom KW - organischer Halbleiter KW - Photodiode KW - Silicium KW - Spritzbeschichten KW - Spritzschicht KW - Sprühdüse KW - Zerstäubung Y1 - 2017 SN - 978-3-8007-4491-6 SP - 747 EP - 750 PB - VDE-Verlag CY - München ER - TY - JOUR A1 - Betz, Michael A. A1 - Büchele, Patric A1 - Brünnler, Manfred A1 - Deml, Sonja A1 - Lechner, Alfred T1 - Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers JF - Journal of micromechanics and microengineering N2 - Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30-50 mu l.min(-1). For spray coating an active area of 25 cm(2) a 2.45-4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of similar to 750 nm using a single micronozzle at a coating speed of 1.7 cm(2).min(-1) reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of similar to 7.4.10(-5) mA.cm(-2), both measured at -2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning. KW - deep reactive ion etching KW - microfluidics KW - organic photodiodes KW - organic semiconductors KW - spray coating KW - venturi nozzles Y1 - 2017 U6 - https://doi.org/10.1088/0960-1317/27/1/015019 VL - 27 IS - 1 PB - IOP Publishing ER - TY - JOUR A1 - Liebherr, Raphaela B. A1 - Hutterer, Albert A1 - Mickert, Matthias J. A1 - Vogl, Franziska C. A1 - Beutner, Andrea A1 - Lechner, Alfred A1 - Hummel, Helmut A1 - Gorris, Hans H. T1 - Three-in-one enzyme assay based on single molecule detection in femtoliter arrays JF - Analytical and bioanalytical chemistry N2 - Large arrays of femtoliter-sized chambers are important tools for single molecule research as well as bioanalytical applications. We have optimized the design and fabrication of two array types consisting of 250 × 250 (62 500) femtoliter chambers either by surface etching of fused silica slides or by polydimethylsiloxane (PDMS) molding. Highly diluted solutions of β-galactosidase were enclosed in such arrays to monitor the fluorogenic reactions of hundreds of individual enzyme molecules in parallel by wide-field fluorescence microscopy. An efficient mechanical sealing procedure was developed to prevent diffusion of the fluorescent reaction product out of the chambers. Different approaches for minimizing non-specific surface adsorption were explored. The signal acquisition was optimized to grant both a large field of view and an efficient signal acquisition from each femtoliter chamber. The optimized femtoliter array has enabled a three-in-one enzyme assay system: First, the concentration of active enzyme can be determined in a digital way by counting fluorescent chambers in the array. Second, the activity of the enzyme bulk solution is given by averaging many individual substrate turnover rates without the need for knowing the exact enzyme concentration. Third-unlike conventional enzyme assays-the distribution of individual substrate turnover rates yields insight into the conformational heterogeneity in an enzyme population. The substrate turnover rates of single β-galactosidase molecules were found to be broadly distributed and independent of the type of femtoliter array. In general, both types of femtoliter arrays are highly sensitive platforms for enzyme analysis at the single molecule level and yield consistent results. KW - ARRAYS KW - Digital concentration readout KW - Enzyme kinetics KW - Fluorescence microscopy KW - Single molecule detection Y1 - 2015 U6 - https://doi.org/10.1007/s00216-015-8910-0 VL - 407 IS - 24 SP - 7443 EP - 7452 PB - Springer ER - TY - JOUR A1 - Bauhuber, Michael A1 - Mikrievskij, Andreas A1 - Lechner, Alfred T1 - Isotropic wet chemical etching of deep channels with optical surface quality in silicon with HNA based etching solutions JF - Materials Science in Semiconductor Processing N2 - Online trace analysis based on UV/Vis spectroscopy requires long detection paths. Therefore an isotropic wet etch process in silicon is developed to fabricate a 300 µm deep channel with low channel wall roughness for desired light guidance application. Four etchant compositions were compared in terms of etching rate, surface roughness and selectivity in a beaker process. The best fitting mixture was selected. To further increase the surface quality (bubble issue) a spin etcher tool is used for producing the channels. The dependence of homogeneity and defect density on media flux, and rotation velocity was investigated. Results show that high rotation velocity and high media flux lead to great defects in the channel wall. Through rotation of the wafer during etching, the etching rate of silicon rises compared to the beaker process due to the rapid removal of etch products and simultaneous supply of fresh etchant. After 38 min of etching, 300 µm deep semi-circular channels with high optical quality (Rq=10 nm±2 nm) over 3 m were produced. Y1 - 2013 UR - https://www.scopus.com/authid/detail.uri?authorId=22980567700#disabled U6 - https://doi.org/10.1016/j.mssp.2013.05.017 VL - 16 IS - 6 SP - 1428 EP - 1433 PB - Elsevier ER - TY - JOUR A1 - Hutterer, Albert A1 - Bauhuber, Michael A1 - Hummel, Helmut A1 - Lechner, Alfred T1 - Real-time analyses of metal contaminations in the ppb-range JF - Solid State Phenomena N2 - In high-tech processing even smallest concentrations of metal ions in process media are of the utmost significance because they cause expensive production failures. Currently, cost-intensive equipment, special trained staff and time consuming analyses are necessary to detect these contaminations in order to avoid failures. The Centers of Excellence Nanochem and Sensorics at the University of Applied Sciences Regensburg (owner of patent PCT/EP2010/064833) and their industrial partner Micro-Epsilon GmbH are developing a new miniaturized measurement device which allows cost-effective real-time analysis of fluidic media for the first time. The system is fully automated and can be directly connected to wet-etch benches. Hence it allows continuous real-time surveillance of metal contaminations in the ppb-range through absorption spectroscopy in process media. For this purpose a very small sample amount of the process medium and a specific complexing agent are mixed together. This leads to an increase in the molar extinction coefficients and though even smallest contaminations become visible. The main parts of our development are the simulation of the different system components, their production and chemical analyses with the evaluation model. KW - Absorption KW - Analysis KW - Complexing Agent KW - Light Guidance KW - Liquid-Core Waveguide KW - Metal Ions KW - Online Measurement KW - Real-Time KW - Total Internal Reflection Y1 - 2013 U6 - https://doi.org/10.4028/www.scientific.net/SSP.195 VL - 195 SP - 269 EP - 273 PB - Trans Tech Publications ER - TY - JOUR A1 - Peter, Daniel A1 - Dalmer, Michael A1 - Lechner, Alfred A1 - Gigler, Alexander M. A1 - Stark, Robert W. A1 - Bensch, Wolfgang T1 - Measurement of the mechanical stability of semiconductor line structures in drying liquids with application to pattern collapse JF - Journal of Micromechanics and Microengineering N2 - Enhanced particle removal processes in wet cleaning as well as drying processes of semiconductor wafers can cause significant lateral forces on surface structures. These forces, however, must not exceed the mechanical stability of structures on the wafer. Thus, a mechanical fracture test was used to assess the lateral mechanical stability of polysilicon line structures in relevant process liquids. The mechanical test was based on nanomanipulation with an atomic force microscope. Compared to fracture tests in air, data acquired in liquid isopropanol revealed a stabilizing effect. The differences in fracture forces can be attributed to a stress corrosion process on the surface. The size of the generated damage was influenced by the viscosity of the surrounding media. Y1 - 2011 U6 - https://doi.org/10.1088/0960-1317/21/2/025001 VL - 21 IS - 2 PB - IOP Science ER - TY - CHAP A1 - Peter, Daniel A1 - Dalmer, Michael A1 - Lotnyk, Andriy A1 - Kienle, Lorenz A1 - Lechner, Alfred A1 - Bensch, Wolfgang T1 - Solid bridging during pattern collapse (stiction) studied on silicon nanoparticles T2 - MRS Online Proceedings Library N2 - The high surface to volume ratio of nanoparticles allows a detailed experimental study of the surface phenomena associated with solid bridging. Besides bulk analyses, the local view on the structure and composition via HRTEM is particularly essential. 50 nm core shell particles consisting of a silicon (Si) core and a SiO2 shell were used as model system to understand surface phenomena appearing for Si-based nanostructures. Evaporative drying from de-ionized water shows the most significant bridging effect based on SiO2. There is only a localized deposition of oxides between the particles during the drying process and no overall oxidation. For the deposition material, silicates are the most likely candidates. Y1 - 2011 U6 - https://doi.org/10.1557/opl.2011.397 VL - 1299 SP - 191 EP - 196 PB - Springer Nature ER - TY - JOUR A1 - Peter, Daniel A1 - Holsteyns, Frank A1 - Dalmer, Michael A1 - Kruwinus, Hans A1 - Lechner, Alfred A1 - Bensch, Wolfgang T1 - A Study on the Structure Collapse Mechanisms for High Aspect Ratio Structures with Application to Clean Processing JF - ECS Meeting Abstracts Y1 - 2009 U6 - https://doi.org/10.1149/MA2009-02/24/2084 VL - MA2009-02 IS - 24 PB - IOP Science ER -