Fertigung laminarer optischer Gitter am HZB

Laminare optische Gitter stellen höchste Anforderungen an die mikrosystemtechnische Fertigung der Mikro und Nano strukturen in Hinsicht auf Präzision und Homogenität. Im Rahmen des EU Projektes Aufbau eines Technologiezent rums für hocheffiziente optische Präzisionsgitter am Helmholtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] wurden die für die Herstellung von laminaren und geblazten Gittern notwendigen Anlagen in Betrieb ge nommen. Gleichzeitig wurde mit der Prozessentwicklung begonnen. In diesem Artikel werden die neuesten Prozessergebnisse von durch Laserinterferenzlithographie LIL in Photoresist erzeugter Gitterstrukturen und deren nur wenige Nanometer tiefe Übertragung in Siliziumsubstrate mittels Ionenstrahl ätzen vorgestellt. english version Laminar optical gratings impose highest demands on microsystem technological manufacturing with regard to precision and uniformity. Within the project Installation of a technology centre for highly efficient precision gratings at Helm holtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] the necessary systems for the manufacturing of laminar and blazed gratings were taken into operation and process development has started. In this article we present the results of grating structures manufactured with laser interference lithography and subse quent ion beam etchin

Scatterometry reference standards to improve tool matching and traceability in lithographical nanomanufacturing

High quality scatterometry standard samples have been developed to improve the tool matching between different scatterometry methods and tools as well as with high resolution microscopic methods such as scanning electron microscopy or atomic force microscopy and to support traceable and absolute scatterometric critical dimension metrology in lithographic nanomanufacturing. First samples based on one dimensional Si or on Si 3 N 4 grating targets have been manufactured and characterized for this purpose. The etched gratings have periods down to 50 nm and contain areas of reduced density to enable AFM measurements for comparison. Each sample contains additionally at least one large area scatterometry target suitable for grazing incidence small angle X ray scattering. We present the current design and the characterization of structure details and the grating quality based on AFM, optical, EUV and X Ray scatterometry as well as spectroscopic ellipsometry measurements. The final traceable calibration of these standards is currently performed by applying and combining different scatterometric as well as imaging calibration methods. We present first calibration results and discuss the final design and the aimed specifications of the standard samples to face the tough requirements for future technology nodes in lithography

Computational strategies to combat COVID-19: useful tools to accelerate SARS-CoV-2 and coronavirus research

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is a novel virus of the family Coronaviridae. The virus causes the infectious disease COVID-19. The biology of coronaviruses has been studied for many years. However, bioinformatics tools designed explicitly for SARS-CoV-2 have only recently been developed as a rapid reaction to the need for fast detection, understanding and treatment of COVID-19. To control the ongoing COVID-19 pandemic, it is of utmost importance to get insight into the evolution and pathogenesis of the virus. In this review, we cover bioinformatics workflows and tools for the routine detection of SARS-CoV-2 infection, the reliable analysis of sequencing data, the tracking of the COVID-19 pandemic and evaluation of containment measures, the study of coronavirus evolution, the discovery of potential drug targets and development of therapeutic strategies. For each tool, we briefly describe its use case and how it advances research specifically for SARS-CoV-2. All tools are free to use and available online, either through web applications or public code repositories.Peer Reviewe

X ray absorption spectroscopy using a self seeded soft X ray free electron laser

X ray free electron lasers XFELs enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x ray bandwidth is an order of magnitude narrower than that of self amplified spontaneous emission SASE , and additional monochromatization is needed. Here we compare L edge x ray absorption spectroscopy XAS of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source LCLS with a new technique based on self seeding of LCLS. We demonstrate how L edge XAS can be performed using the self seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x ray spectroscopy measurement

Integration of moth eye structures into a poly dimethylsiloxane stamp for the replication of functionalized microlenses using UV nanoimprint lithography

The increasing demand for low cost camera modules for mobile devices requires technological solutions for the manufacturing process. One of the most promising fabrication processes for microlenses for camera modules is UV nanoimprint lithography. In a typical fabrication process, an elastomer stamp is used to replicate microlenses. In this work, a method is presented to integrate moth eye structures as an antireflective layer into a poly dimethylsiloxane PDMS stamp containing a microlens array. The integration of these structures is done by a thermoforming process. Due to the integration of the moth eye structures into the PDMS stamp, the optical performance of the replicated microlenses can be improved and no additional processing steps are necessary after the replication proces

NH4OH-based etchants for silicon micromachining. Influence of additives and stability of passivation layers

Solution based on ammonium hydroxide and water were investigated for anisotropic etching of monocrystalline silicon. In 2.65 M NH sub 3 solutions at 80 degree C, the addition of H sub 2 O sub 2 in a concentration between 0.65 x 10 high -2 M and 1.84 x 10 high -2 M increases the silicon etch rate in the (100) direction to 75 mym/h, which is a factor of about 2.5 higher compared to pure etchants. In addition, when the pH value was adjusted above 11.3, silicon etching proceeds in H sub 2 O sub 2 -doped solutions without formation of pyramidal-shaped hillocks. The influence of the pH value and H sub 2 O sub 2 concentration on the etching behaviour is discussed in detail. Passivation layers, like silicon oxides and silicon nitrides formed under various preparation conditions, and metals show excellent stability in AHW solutions. The temperature dependence of etch rates as well as the influence of post-treatments on the etching behaviour is discussed

Nanoprägen in Polymerfolien als Fertigungsverfahren für fluidische Mikro Nano Systeme Nanoembossing in Polymer Foils as a Fabrication Technique for fluidic Micro Nano Systems

Um die Funktionalität der Mikrosystemtechnik durch die Integration von Submikrometer und Nanometerstrukturen in sogenannte Mikro Nano Systeme erweitern zu können, müssen industriekompatible Produktionstechnologien entwickelt werden, die eine Strukturierung im Mikro und Nanometerbereich für ein breites Nutzerspektrum ermöglichen und für eine Fertigung von mikro und nanostrukturierten Komponenten auch im industriellen Einsatz in Frage kommen. Die Intention der vorliegenden Arbeit ist es, für diese technologische Aufgabenstellung einen möglichen Lösungsansatz durch Untersuchungen zum Nanoprägen als ein für die Nanostrukturierung von Kunststoffen adaptiertes Heissprägeverfahren weiterzuentwickeln und den enormen Nutzen des Verfahrens für die Fertigung fluidischer Mikro Nano Systeme durch Applikationsbeispiele aus dem Bereich der Life Sciences zu veranschauliche

Quasicrystalline structured light harvesting nanophotonic silicon films on nanoimprinted glass for ultra thin photovoltaics

We present nanophotonic light harvesting crystalline silicon c Si thin films on glass exhibiting ten fold transversely quasicrystalline lattice geometry on 6 x 8 mm2 area. The c Si architectures with a nearest neighbor distance of 650 nm are fabricated by nanoimprinting the desired quasicrystalline geometry into sol gel coated glass substrates followed by Si deposition of 240 nm to 270 nm thickness, self organized solid phase crystallization and selective chemical etching. Broadband absorption measurements on these quasicrystalline structured c Si architectures yield a very significant improvement in light trapping in the near infrared regime and an enhanced light coupling due to a graded index effect in comparison to the unstructured sample. The average value of maximum achievable short circuit current density jsc, max of solar cells with such quasicrystallinestructured c Si absorber geometry 19.3 mA cm2 is more than double in comparison to the jsc, max of unstructured planar films of the same thickness 9.3 mA cm2 and remains stable for light incident angles up to 60 . In comparison to a 320 nm thick c Si film on textured ZnO Al substrate as widely used for light trapping in amorphous microcrystalline Si thin film photovoltaics, still a 65 increased jsc, max is observable for the presented quasicrystalline c Si structures. The nanophotonic light trapping efficiency of these transversely quasicrystalline c Si nanoarchitectures is among the highest values for experimentally realized structures, revealing their promising influence for broadband and isotropic light trapping for economically viable and efficient ultra thin solar cell