TY - CHAP A1 - Thumann, Philipp A1 - Schmauser, Philipp A1 - Buchner, Stefan A1 - Wagner, Marcus T1 - Festigkeitsbewertung von hochbeanspruchten Kupferkomponenten T2 - Tagung Auslegung von Bauteilen aus Kupfer und Kupferlegierungen, 14. und 15. Mai 2025, Goslar N2 - Es wird gezeigt, wie durch ein ganzheitliches Konzept, beginnend mit der Modellerstellung eines umfangreichen FE-Berechnungsmodells bis hin zur Festigkeitsbewertung unter Verwendung speziell ermittelter Werkstoffkenndaten, die Betriebssicherheit von hochbeanspruchten Kupferkomponenten sichergestellt werden kann. Mit den durchgeführten Werkstoffversuchsreihen an wärmebehandelten und weichgeglühten Kupferproben aus Cu-ETP R250 wurden neben den Standard-Werkstoffkenndaten wie Streckgrenze Rp, Zugfestigkeit Rm, Bruchdehnung A und Elastizitätsmodul E Parameter zur Beschreibung des Werkstoffverhaltens bei zyklischer Belastung bestimmt. Zusätzlich wurde wurde in Abhängigkeit der Wärmebehandlung und der damit verbundenen Ver- oder Entfestigung die Schwingfestigkeit eruiert. Somit ist mit der vorgestellten methodischen Vorgehensweise unter Verwendung tatsächlicher Werkstoffsteifigkeiten und umfangreicher Schwingfestigkeitsdaten eine Betriebsfestigkeitsbewertung möglich. KW - zyklischer Werkstoffversuch KW - Kupfer KW - Schwingfestigkeit Y1 - 2025 U6 - https://doi.org/10.48447/Cu-2025-569 PB - Deutscher Verband für Materialforschung und -prüfung e.V. ER - TY - JOUR A1 - Schels, Andreas A1 - Edler, Simon A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Ritter, Daniela A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Meyer, Manuel A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner, Philipp A1 - Schreiner, Rupert T1 - In situ quantitative field emission imaging using a low-cost CMOS imaging sensor JF - Journal of Vacuum Science & Technology B N2 - Spatially resolved field emission measurements represent an important factor in further development of existing field emitter concepts. In this work, we present a novel approach that allows quantitative analysis of individual emission spots from integral current-voltage measurements using a low-cost and commercially available CMOS camera. By combining different exposure times to extrapolate oversaturated and underexposed pixels, a near congruence of integral current and image brightness is shown. The extrapolation also allows parallel investigation of all individual tips participating in the total current with currents ranging from a few nanoampere to one microampere per tip. The sensitivity, which is determined by the integral brightness-to-current ratio, remains unchanged within the measurement accuracy even after ten full measurement cycles. Using a point detection algorithm, the proportional current load of each individual tip of the field emitter array is analyzed and compared at different times during the initial measurement cycle. Together with the extracted I-V curves of single emission spots from the integral measurement, the results indicate the effect of premature burnout of particularly sharp tips during conditioning of the emitter. KW - ARRAYS KW - ELECTRON-EMISSION KW - EMITTERS KW - FakANK Y1 - 2022 U6 - https://doi.org/10.1116/6.0001551 VL - 40 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Edler, Simon A1 - Schels, Andreas A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner Philipp, A1 - Schreiner, Rupert T1 - Origin of the current saturation level of p-doped silicon field emitters JF - Journal of Vacuum Science & Technology B N2 - Using p-type semiconductors for field emitters is one simple way to realize an integrated current limiter to improve the lifetime of the cathode. In this work, the origin of the current saturation of p-type silicon emitters is investigated in detail. Single emitters are electrically characterized and compared to simulation results. With a simulation model considering a high surface generation rate and elevated tip temperature, a good agreement to the measured data is found. This observation is supported further by alteration of the surface experimentally. Electrical measurements after different treatments in hydrofluoric acid as well as heated and subsequent operation at room temperature are well explained by the influence of surface generation. Furthermore, it is shown that the field penetration leads to a small voltage drop and a strong geometry-dependent reduction of the field enhancement factor. KW - EMISSION KW - GROWTH KW - NATIVE-OXIDE Y1 - 2022 U6 - https://doi.org/10.1116/6.0001554 VL - 40 IS - 1 PB - AIP Publishing ER - TY - CHAP A1 - Buchner, Philipp A1 - Kaiser, Alexander A1 - Hausladen, Matthias A1 - Bartl, Mathias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Silicon Nanowire Field Emitters with Integrated Extraction Gates Using Benzocyclobutene as an Insulator T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - We are continuously improving the performance of our field emission electron sources. In this work a geometrically optimized design of electron sources with silicon nanowire field emitters on pillars was fabricated. This new design increased the packing density of the emitters by using a hexagonal arrangement of the pillars and a pillar spacing of 40 µm. Benzocyclobutene was used as the insulator material for an integrated (Cr/Ni) extraction gate. A modified fabrication process for the field emitters further improved reproducibility and reliability. An emission current of about 0.4 mA was measured for 30 minutes at an extraction voltage of 250 V and an anode voltage of 500 V. Electron transmission through the gate reached almost 100%. Y1 - 2024 U6 - https://doi.org/10.1109/IVNC63480.2024.10652314 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Hausladen, Matthias A1 - Bomke, Vitali A1 - Buchner, Philipp A1 - Bachmann, Michael A1 - Knapek, Alexandr A1 - Schreiner, Rupert T1 - Influence of Geometrical Arrangements of Si Tip Arrays Fabricated by Laser Micromachining on their Emission Behaviour T2 - 2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France N2 - ensely packed emitters on a field emission array lead typically to mutual shielding. Taking biology as a role model for geometric arrangements could be a way to reduce this effect. For comparison, two electron sources, one with a spiral and a second with conventional rectangular (orthogonal) arranged emitters, were fabricated and investigated. Emission currents of 6 µA in the spiral ordered array and 120 µA in the rectangular array were reached with an extraction voltage of 400 V. From a mid-term measurement over 1 h a current stability of ±8.8 % (spiral) respectively ±5.7 % (rectangular) with a mean degradation of -3.0 µA/h (spiral) and -0.12 µA/h (rectangular) could be observed. KW - aperture field KW - emission grid KW - Fabrication KW - laser micromachining KW - parastichy tip arrangements KW - silicon field emission KW - Stability analysis KW - Spirals KW - Field emitter array KW - Voltage measurement Y1 - 2021 SN - 978-1-6654-2589-6 U6 - https://doi.org/10.1109/IVNC52431.2021.9600717 SN - 2380-6311 PB - IEEE CY - Piscataway, N.J. ER - TY - CHAP A1 - Buchner, Philipp A1 - Bomke, Vitali A1 - Hausladen, Matthias A1 - Edler, Simon A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Investigation on the Emission Behaviour of p-doped Silicon Field Emission Arrays with Individually Controllable Single Tips T2 - 2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France N2 - Four individually controllable emission tips consisting of <111> p-Type silicon, were structured on a glass substrate by laser ablation. A matching extraction grid was manufactured in the same manner and aligned with the emitters. The resulting samples were characterized in ultra-high vacuum. As expected, the individual currents show a strong saturation and in the saturation region a considerably lower current fluctuation than n-type silicon due to charge carrier depletion. The individual tips behave completely independent behaviour from each other and the overall emission can be deduced from the sum of the currents through the individual tips. Y1 - 2021 SN - 978-1-6654-2589-6 U6 - https://doi.org/10.1109/IVNC52431.2021.9600756 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Hecht, Fabian A1 - Bauereiβ, Florian A1 - Sellmair, Josef A1 - Buchner, Philipp A1 - Hausladen, Matthias A1 - Schreiner, Rupert T1 - Electron Beam Induced Growth of Carbon Nanotips on Tungsten and Silicon Fieldemitters T2 - 2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA N2 - In our experiments we grew electron emitting carbon nanostructures on tungsten tips. Subsequently, we transferred the growth process to pre-structured phosphorus-doped n-type silicon and obtained emitting carbon nanostructures directly grown on silicon. After growth of the nanostructures, the silicon field emitters showed increased emission currents of 76 nA at 1.1 kV (compared to 6 nA under the same conditions before growth). KW - Behavioral sciences KW - Nanostructures KW - Silicon KW - Carbon dioxide KW - Current measurement KW - Electron beams KW - Tungsten Y1 - 2023 SN - 979-8-3503-0143-4 U6 - https://doi.org/10.1109/IVNC57695.2023.10188960 SP - 160 EP - 162 PB - IEEE ER - TY - CHAP A1 - Allaham, Mohammad M. A1 - Buchner, Philipp A1 - Schreiner, Rupert A1 - Knápek, Alexandr T1 - Testing the performance of Murphy-Good plots when applied to current-voltage characteristics of Si field electron emission tips T2 - 2021 34th International Vacuum Nanoelectronics Conference (IVNC): 5-9 July 2021, Lyon, France N2 - Murphy-Good plots are the most recent type of the analysis methods in the field electron emission theory, this type of plots has several useful characteristics such as: having the very-nearly straight line to represent the current-voltage characteristics and the absence of the correction factors in the mathematical procedure of the analysis process. In this study, n-type <111> and <100> Si chips containing four individual emitters are used as base emitters and mounted in a diode configuration field emission setup where the experiments are operated in an ultra-high vacuum ( 10-7 Pa). Each chip has four individual controllable emitters with 5 µm distance between the Si tips and the same material grid. Laser micromachining and subsequent wet chemical etching technique is used to structure and polish the tips. Murphy-Good plots are used to study the behavior of the Si individual tips and compare the results with the array current by extracting the field emission characterization parameters of the emitters. KW - characterization parameter KW - Current-voltage characteristics KW - electron emission KW - electron source KW - Limiting KW - Micromachining KW - Murphy-Good plot KW - n-type Si chip KW - RESISTANCE KW - safety KW - silicon Y1 - 2021 U6 - https://doi.org/10.1109/IVNC52431.2021.9600690 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Bartl, Mathias A1 - Buchner, Philipp A1 - Hausladen, Matthias A1 - Asgharzadehkhorasani, Ali A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Simulations and Investigations of Silicon Nanowire Field Emitters T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - The emission behavior of field emission electron sources consisting of a silicon nanowire cathode, an extraction grid electrode and a planar anode was investigated based on a particle tracing simulation using FEM. The focus was on the influence of the grid geometry as well as the positioning of the grid relative to the emitters on the electron transmission. The highest transmission can be achieved with the emitter tips protruding 10 µm trough the extraction grid openings. The transmission decreases more rapidly with increasing distance between the tip and the grid the thicker the grid is. Y1 - 2024 U6 - https://doi.org/10.1109/IVNC63480.2024.10652355 SP - 1 EP - 2 PB - IEEE ER - TY - JOUR A1 - Hausladen, Matthias A1 - Buchner, Philipp A1 - Bartl, Mathias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Integrated multichip field emission electron source fabricated by laser-micromachining and MEMS technology JF - Journal of Vacuum Science & Technology B N2 - In this work, high-current field emission electron source chips were fabricated using laser-micromachining and MEMS technology. The resulting chips were combined with commercially available printed circuit boards (PCBs) to obtain a multichip electron source. By controlling the separate electron sources using an external current control circuit, we were able to divide the desired total current evenly across the individual chips deployed in the PCB-carrier. In consequence, we were able to show a decreased degradation due to the reduced current load per chip. First, a single electron source chip was measured without current regulation. A steady-state emission current of 1 mA with a high stability of ±1.3% at an extraction voltage of 250 V was observed. At this current level, a mean degradation slope of −0.7 μA/min with a nearly perfect transmission ratio of 99% ± 0.4% was determined. The measurements of a fully assembled multichip PCB-carrier electron source, using a current control circuit for regulation, showed that an even distribution of the desired total current led to a decreased degradation. This was determined by the increase in the required extraction voltage over time. For this purpose, two current levels were applied to the electron source chips of the PCB-carrier using an external current control circuit. First, 300 μA total current was evenly distributed among the individual electron source chips followed by the emission of 300 μA per electron source chip. This allows the observation of the influence of a distributed and nondistributed total current, carried by the electron source chips. Thereby, we obtained an increase in the mean degradation slope from +0.011 V/min (300 μA distributed) to +0.239 V/min (300 μA per chip), which is approximately 21 times higher. Moreover, our current control circuit improved the current stability to under 0.1% for both current levels, 300 μA distributed and 300 μA per chip. KW - MEMS technology KW - Field emitter arrays KW - Electron sources KW - Laser micromachining Y1 - 2024 U6 - https://doi.org/10.1116/6.0003233 VL - 42 IS - 1 PB - AIP Publishing ER -