TY - GEN A1 - Varlamova, Olga A1 - Reif, Jürgen A1 - Stolz, Michael A1 - Borcia, Rodica A1 - Borcia, Ion-Dan A1 - Bestehorn, Michael T1 - Wetting properties of LIPSS structured silicon surfaces T2 - The European Physical Journal B N2 - The controlled dynamics of liquid drops via generation of specific wetting states on a solid surface is of great interests both in the fundamental and applied sciences. Considering that the wettability is strongly dependent on the surface topography and surface roughness, we investigate – through experiments and theory – the effect of laser-induced periodic surface structures (LIPSS) generated on silicon (100) targets as a control parameter of wetting properties. To obtain structured silicon surfaces with different morphological features, we patterned the surface by irradiation with femtosecond pulses from an amplified Ti:Sapphire laser system (790 nm/100 fs/1 kHz) at a fluence in the range of 0.4–1.2 J/cm2 on a spot with a diameter about of 100 μm. Variation of the applied irradiation dose results in surface modifications with the roughness about of a few tens of nanometers are ranging from regular LIPSS patterns with the lateral period of about 500–700 nm to complex agglomerations of 3-D microstructures with several-μm feature size. The theoretical study on the correlation of wetting properties with the surface topography has been performed within a phase field model. We found an excellent agreement of numerical results with experiments. Y1 - 2019 U6 - https://doi.org/10.1140/epjb/e2019-90672-2 SN - 1434-6036 SN - 1434-6028 VL - 92 IS - 5 ER - TY - GEN A1 - Ehrig, Lutz A1 - Schenk, Hermann A1 - Wall, Franziska A1 - Melnikov, Anton A1 - Stolz, Michael A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Conrad, Holger T1 - Electrostatic all-silicon MEMS audio transducer for in-ear audio applications – acoustic measurements and modelling approach T2 - 23rd International Congress on Acoustics, Aachen, Germany, 2019 Y1 - 2019 U6 - https://doi.org/10.18154/RWTH-CONV-239893 ER - TY - GEN A1 - Spitz, Barbara A1 - Wall, Franziska A1 - Schenk, Hermann A1 - Melnikov, Anton A1 - Ehrig, Lutz A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald A1 - Pufe, Wolfram T1 - Audio-Transducer für In-Ear-Anwendungen auf der Basis CMOS-kompatibler, elektrostatischer Biegeaktoren T2 - MikroSystemTechnik-Kongress, Berlin, Germany, 2019 N2 - Recently an innovative mSpeaker technology, based on a novel kind of CMOS compatible small gap electrostatic actuators for large deflection, has been introduced [1]. In this paper, we devise methods to model such speakers in terms of lumped parameters using the deflection of the beam centre as sole dynamic variable. Optical, acoustical and finite element methods (FEM) are used to validate the non-linear lumped parameter model (LPM). The experimental evaluation and LPM simulations of the total harmonic distortion reveal deeper insights into the mechanisms governing linearity. Y1 - 2019 SP - 54 EP - 57 PB - VDE-Verlag ER - TY - GEN A1 - Melnikov, Anton A1 - Schenk, Hermann A1 - Wall, Franziska A1 - Spitz, Barbara A1 - Ehrig, Lutz A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald A1 - Stolz, Michael T1 - Minimization of nonlinearities in nano electrostatic drive actuators using validated coupled-field simulation T2 - SPIE Conference: MOEMS and Miniaturized Systems XIX, San Francisco, USA, 2020, Proc. SPIE 11293 Y1 - 2020 U6 - https://doi.org/10.1117/12.2551271 ER - TY - CHAP A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Stolz, Michael A1 - Arscott, S. A1 - Conrad, Holger A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Electrostatic bending actuators with liquid filled nanometer scale gap T2 - MEMS 2017, the 30th IEEE International Conference on Micro Electro Mechanical Systems, Las Vegas, Nevada, USA, January 22-26 2017 Y1 - 2017 UR - http://ieeexplore.ieee.org/document/7863369/ SN - 978-1-5090-5078-9 SN - 978-1-5090-5079-6 SP - 175 EP - 178 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Langa, Sergiu A1 - Conrad, Holger A1 - Kaiser, Bert A1 - Stolz, Michael A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Schimmanz, Klaus A1 - Schenk, Harald T1 - Technological aspects of a new micro-electro-mechanical actuation principle: nano e-drive T2 - Microsystem Technologies Y1 - 2017 U6 - https://doi.org/10.1007/s00542-017-3360-6 SN - 1432-1858 VL - 23 IS - 1 SP - 5697 EP - 5708 ER - TY - GEN A1 - Conrad, Holger A1 - Schenk, Harald A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Gaudet, Matthieu A1 - Schimmanz, Klaus A1 - Stolz, Michael A1 - Lenz, Miriam T1 - A small-gap electrostatic micro-actuator for large deflections T2 - Nature Communications Y1 - 2015 U6 - https://doi.org/10.1038/ncomms10078 SN - 2041-1723 IS - 6 SP - 10078 ER - TY - CHAP A1 - Schenk, Harald A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Schimmanz, Klaus T1 - A novel electrostatic micro-actuator class and its application potential for optical MEMS T2 - 2016 International Conference on Optical MEMS and Nanophotonics,31 July-04 August 2016, Singapore, proceedings Y1 - 2016 SN - 978-1-5090-1036-3 U6 - https://doi.org/10.1109/OMN.2016.7565867 SP - Tu 3.11-1 EP - Tu 3.11-2 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Ehrig, Lutz A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schenk, Harald T1 - Optische Charakterisierungsmethoden von siliziumbasierten MEMS mit verdeckten Strukturen T2 - MikroSystemTechnik-Kongress, Berlin, Germany, 2019 N2 - In der Arbeitsgruppe integrierte Siliziumsysteme des Fraunhofer IPMS werden am Standort Cottbus innovative Anwen-dungen eines neuartigen nanoskopischen elektrostatischen Antriebs (nanoskopic electrostatic drive – NED) untersucht. Eine der vielversprechendsten Anwendungen sind Lautsprecher. Vollständig aus Silizium gefertigte MEMS-Lautsprecher auf Basis von NED-Biegeaktoren werden vor den akustischen Messungen mechanisch und elektrisch cha-rakterisiert. Beidseitig eingespannte elektrostatisch betriebene in-plane NED-Aktoren werden dabei über einen Fre-quenzbereich von 20 Hz bis 20 kHz angeregt. Dabei sind die Strukturen oft verdeckt, was ihre Charakterisierung er-schwert. Es werden zerstörungsfreie optische Methoden präsentiert, mit deren Hilfe die Bestimmung der mechanischen Schwingungseigenschaften einzelner Aktoren ermöglicht wird sowie die Beweglichkeit im verdeckten Zustand nach-gewiesen werden kann. Y1 - 2019 UR - https://www.ipms.fraunhofer.de/de/events/2019/mst-kongress.html SP - 366 EP - 369 PB - VDE-Verlag ER - TY - GEN A1 - Melnikov, Anton A1 - Schenk, Hermann A. G. A1 - Monsalve, Jorge Mario A1 - Wall, Franziska A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Langa, Sergiu A1 - Kaiser, Bert T1 - Coulomb-actuated microbeams revisited: experimental and numerical modal decomposition of the saddle-node bifurcation T2 - Microsystems & Nanoengineering N2 - Electrostatic micromechanical actuators have numerous applications in science and technology. In many applications, they are operated in a narrow frequency range close to resonance and at a drive voltage of low variation. Recently, new applications, such as microelectromechanical systems (MEMS) microspeakers (µSpeakers), have emerged that require operation over a wide frequency and dynamic range. Simulating the dynamic performance under such circumstances is still highly cumbersome. State-of-the-art finite element analysis struggles with pull-in instability and does not deliver the necessary information about unstable equilibrium states accordingly. Convincing lumped-parameter models amenable to direct physical interpretation are missing. This inhibits the indispensable in-depth analysis of the dynamic stability of such systems. In this paper, we take a major step towards mending the situation. By combining the finite element method (FEM) with an arc-length solver, we obtain the full bifurcation diagram for electrostatic actuators based on prismatic Euler-Bernoulli beams. A subsequent modal analysis then shows that within very narrow error margins, it is exclusively the lowest Euler-Bernoulli eigenmode that dominates the beam physics over the entire relevant drive voltage range. An experiment directly recording the deflection profile of a MEMS microbeam is performed and confirms the numerical findings with astonishing precision. This enables modeling the system using a single spatial degree of freedom. KW - Engineering KW - NEMS KW - Sensors Y1 - 2021 U6 - https://doi.org/10.1038/s41378-021-00265-y SN - 2055-7434 VL - 7 IS - 1 ER -