Multi-technology design of an integrated MEMS-based RF oscillator using a novel silicon-ceramic compound substrate. - In: 2015 German Microwave Conference (GeMiC), ISBN 978-1-4799-6681-3, (2015), S. 406-409
http://dx.doi.org/10.1109/GEMIC.2015.7107839
Automated reel-to-reel fluidic self-assembly for the production of solid state lighting modules. - In: MRS online proceedings library, ISSN 1946-4274, Bd. 1761 (2015), insges. 6 S.
We report the implementation of a first automated reel-to-reel fluidic self-assembly system based on surface tension driven self-assembly for macroelectronics application. The reported system incorporates precisely controlled and automated agitation, web moving and component recycling and dispensing system and enables continuous parallel assembly of semiconductor chips at a high rate (15k chips per hour using 2.5 cm wide web) and assembly yield (>99%) under optimal condition. In principle, scaling to any throughput should be possible considering the parallel nature of self-assembly. The process overcomes the limitations on area and throughput of prior methods. It provides a new platform for macroelectronics to enable the integration of microscopic high performance inorganic semiconductors on flexible or stretchable substrates with any desired location, pitch, and integration density. As an example we demonstrate the fabrication of a solid state area lighting panel.
https://doi.org/10.1557/opl.2015.679
Ge addition during 4H-SiC epitaxial growth by CVD: mechanism of incorporation. - In: Materials science forum, ISSN 1662-9752, Bd. 821/823 (2015), S. 115-120
http://dx.doi.org/10.4028/www.scientific.net/MSF.821-823.115
Nanocolumnar growth of sputtered ZnO thin films. - In: Thin solid films, ISSN 1879-2731, Bd. 591.2015, Part B, S. 230-236
http://dx.doi.org/10.1016/j.tsf.2015.04.009
Electrostatic parallel-plate MEMS switch on silicon-ceramic-composite-substrates. - In: 2015 German Microwave Conference (GeMiC), ISBN 978-1-4799-6681-3, (2015), S. 414-417
http://dx.doi.org/10.1109/GEMIC.2015.7107841
RF-MEMS-platform based on silicon-ceramic-composite-substrates. - In: 2015 German Microwave Conference (GeMiC), ISBN 978-1-4799-6681-3, (2015), S. 398-401
http://dx.doi.org/10.1109/GEMIC.2015.7107837
Analysis of the resin transfer molding (RTM) process for FRP and its process simulation fundamentals. - In: AIP conference proceedings, ISSN 1551-7616, Bd. 1664 (2015), 060010, insges. 5 S.
FRP technologies enable the production of lightweight components. The RTM technique is attractive to obtain vehicle parts with little post-processing in industrial scales. The closed mold process provides a desired freedom in part-design combined with high and reproducible production rates compared to other FRP processes. However, the shorter the mold-closed time the higher the risk to run into quality consistency issues resulting from air entrapments or voids due to degassing. This is a major obstacle to FRP processes in general. Other effects on fiber volume content and surface quality can be detected. These factors can be influenced by the choice of process parameters, thus flow pattern determining capillary forces, resin reaction velocity, reaction and mold temperature and others which can be specifically addressed by the change of simple process parameters. The dominant parameters on capillary forces are identified. Investigations were carried out to reduce mold-closed time to less than 5 minutes with reproducible high quality components with a minimum of voids for a serial production process. The essential process factors of the RTM process are identified and mathematically modeled. In particular, well known effects are comprehended in a quantitative approach that permits to specifically set up an industrial process and optimize achievable quality attributes. The void content in a FRP component is critical to mechanical performance and visual acceptance. The developed and presented process understanding allows to quantitatively predetermine achievable part performance at minimum cycle times. The process trials were conducted using a DOE-approach under consideration of material and process parameters for simple 2D parts. A visualization of the flow pattern in the cavity is presented and compared to the new approach of calculating the flow front development. The analysis shows the impact of principle process parameters on the achievable part quality.
http://dx.doi.org/10.1063/1.4918428
Localized collection of airborne analytes: a transport driven approach to improve the response time of existing gas sensor designs including SERS based detection of small molecules. - In: MRS online proceedings library, ISSN 1946-4274, Bd. 1746 (2015)
We describe a new transport mechanism that supports the localized collection of airborn analytes at higher rates when compared to diffusion based standard commonly used. It combines advanced aerosol science with novel nanosensor designs. Background: The detection of single molecular binding events has been a recent trend in sensor research introducing various sensor designs where the active sensing elements are nanoscopic in size. While it is possible to detect single binding events, the research has not yet addressed the question of how to effectively transport airborne analytes to these point-like sensing structures. Currently, diffusion-only-transport is used and it becomes increasingly unlikely for an analyte molecule to "find" and interact with sensing structures where the active area is shrunk in size, trading an increased sensitivity with a long response time. Approach: Instead of using diffusion-only-transport, this report introduces various analyte charging methods and electrodynamic nanolens based analyte concentration concepts to transport airborne analytes to nanoscopic sensing points to improve the response time of existing gas sensor designs. We demonstrate localized collection of analytes over a wide range of molecular weights ranging from 3×1017 to 1×102 Daltons, including (i) microscopic analyte particles, (ii) inorganic nanoparticles, all the way down to (iii) small organic molecules. We also demonstrate first experimental results towards an programmable active matrix based analyte collection approach referred to as "Airborn Analyte Memory Chip/Recorder" for "OFFSITE" analyte analysis, which (i) takes samples of the particles or molecules in an Aerosol at specific points in time, (ii) transports the analyte sample to a designated spot on a surface, (iii) concentrates the analyte at this spot to achieve an amplification, (iv) repeats this sequence until the recording matrix is full, and (v) reads out the analyte matrix on the chip. Implications: In all cases we find that the collection rate is several orders of magnitudes higher than in the case where the discovered collection schemes is turned off and where collection is driven by diffusion-only-transport. The collection scheme is integrated on an existing surface-enhanced Raman spectroscopy based sensor. In terms of response time, the process is able to detect analytes at 9 parts per million within 1 second. As a comparison, 1 hour is required to reach the same signal level when diffusion-only-transport is used. The novel "Airborn Analyte Memory Chip/Recorder" achieved by this approach could be a commodity item that is placed in an environment that a user would like to keep a record from. The information is retrieved on an as needed basis. Offsite analysis of the chip storing the information would make this approach more economical than an online monitoring system for all kinds of threads.
http://dx.doi.org/10.1557/opl.2015.398
A passive microsystem for detecting multiple acceleration events beyond a threshold. - In: Microelectronic engineering, Bd. 145 (2015), S. 104-111
http://dx.doi.org/10.1016/j.mee.2015.03.023
Geschlossenporiger Aluminiumschaum mit Faserverstärkung. - In: Tagungsband, (2015), S. 399-407
Der Einsatz von Metallschäumen, insbesondere von Aluminiumschäumen, wird heutzutage noch sehr oft durch die, im Vergleich zu den Monomaterialien schlechteren mechanischen Eigenschaften, begrenzt. Eine Verbesserung der Druckfestigkeiten, Biegefestigkeiten und des Energieabsorptionsvermögens ist hierbei das Ziel der vorgestellten Untersuchungen. Metallische, zelluläre Werkstoffe weisen eine Vielzahl einzigartiger Eigenschaften auf, die neuartige Anwendungen jenseits der bekannten Werkstoffe erlauben. Besonders hervorzuheben ist ihre geringe Dichte und somit eine geringe Masse im Verhältnis zum Volumen, eine hohe Druckfestigkeit und ein gutes Dämpfungsvermögen. In diesem Vortrag werden aktuelle Untersuchungen zur komplexen Herstellung, zu den Eigenschaften und Analysen von verstärkten geschlossenporigen Aluminiumschäumen im pulvermetallurgischen Verfahren vorgestellt. Als Verstärkungsmaterial kommen dabei Glasfasern, Kohlenstofffasern und CNT zum Einsatz.