MOEMS tunable microlens made of aluminum nitride membranes

Leopold, Steffen; Polster, Tobias; Paetz, D.; Knoebber, Fabian; Ambacher, O.; Sinzinger, Stefan; Hoffmann, Martin

doi:10.1117/1.jmm.12.2.023012

Cited by 10 publications

(5 citation statements)

References 14 publications

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“…If the energy is beyond a certain threshold, the layer is strongly (0 0 2) oriented and the way of ion bombardment does not seem to be important. Furthermore, in [29] it is shown that the nitrogen content in the plasma can be varied in a wide range without losing the nanocrystalline columnar structure of the AlN film.…”

Section: Resultsmentioning

confidence: 99%

“…Die piezoelektrische Aktivität sowie die CMOS Kompatibilität des Materials qualifizieren es für den Einsatz in den Bereichen der Hochfrequenz-MEMS [1] und des "energy harvesting" [2]. Resultierend aus der Nanokristallinität gesputterter AlN-Schichten sind diese mechanisch sehr stabil und da das Material im sichtbaren optischen Bereich transparent ist, können für MOEMS Applikationen mit freitragenden AlN-Strukturen sowohl Linsen [3] als auch Federn [4] nen Balken, ergibt sich der durchschnittliche Stressgradient in der Schicht vor der Freistellung aus folgender Beziehung [11]: [12]. Der intrinsische Stress der Nukleationszone und die mit der Schichtdicke steigende Zugspannung muss folglich mit einer quantitativ äquivalenten, aber invers gerichteten Schichtspannung kompensiert werden.…”

Section: Einführungunclassified

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Variation of the intrinsic stress gradient in thin aluminum nitride films

Mehner¹,

Leopold²,

Hoffmann³

2013

J. Micromech. Microeng.

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Im Rahmen des Beitrags wird die Variation des intrinsischen Stressgradienten in reaktiv gesputterten Aluminiumnitridschichten (AlN) vorgestellt. Erstmals werden Prozessparameter identifiziert, deren gezielte Veränderung während des Sputterprozesses dazu dient, den Stressgradienten dünner AlN-Schichten direkt im Prozess einzustellen. Als wesentliche Parameter werden das Gasflussverhältnis der beiden Sputtergase Argon (Ar) und Stickstoff (N2) sowie die Sputterleistung präsentiert. Sowohl die Erzeugung großer positiver bzw. negativer als auch die Kompensation des intrinsischen Stressgradienten werden mittels freigestellter einseitig eingespannter Mikrobalken gezeigt. Darüber hinaus wird der Einfluss eines nachfolgenden Temperschritts auf den Stressgradienten in einer AlN-Schicht untersucht.

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Section: Resultsmentioning

confidence: 99%

Section: Einführungunclassified

Variation of the intrinsic stress gradient in thin aluminum nitride films

Mehner¹,

Leopold²,

Hoffmann³

2013

J. Micromech. Microeng.

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“…Since a 0 3 , β 0 3 and f 0 1 stay constant over the zoom range, we can use (8) to calculate β 0 2 at any given overall focal length f ′ within the zoom range. We use (5), (6) and (2) to receive the missing values of e 0 1 and f 0 2 :…”

Section: Geometrical Relationsmentioning

confidence: 99%

“…Tuneable lenses offer the possibility of changing their focal length without elements moving along the optical axis (e.g. [2] [3] [4] [5]). Therefore, no additional installation space is needed to allow for such a longitudinal movement.…”

Section: Introductionmentioning

confidence: 99%

Zoom systems with tuneable lenses and linear lens movements

Lenk

Mitschunas

Sinzinger

2019

J. Eur. Opt. Soc.-Rapid Publ.

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Background: Classical zoom lenses are based on movements of sub-modules along the optical axis. Generally, a constant image plane position requires at least one nonlinear sub-module movement. This nonlinearity poses a challenge for the mechanical implementation. Tuneable lenses can change their focal length without moving along the optical axis. This offers the possibility of small system lengths. Since the focal range of tuneable lenses with significant aperture diameters is still limited, the use of tuneable optics in zoom lenses is usually restricted to miniaturized applications. Methods: To solve the challenge of the nonlinear movement in classical zoom lenses and the limitations of tuneable lenses for macroscopic applications we propose a combination of both concepts. The resulting 'Hybrid Zoom Lens' involves linear movements of sub modules as well as changing the focal length of a tuneable lens. The movements of the sub-modules and the focal length tuning of the lens are already determined by the collinear layout of the zoom lens. Therefore, we focus on collinear considerations and develop a method that allows a targeted choice of specific collinear layouts for our 'Hybrid zoom lenses'. Results: Based on examples and an experimental setup we demonstrate the feasibility of our approach. We apply the proposed method to examples of classical zoom lenses and zoom lenses based exclusively on tuneable lenses. Thereby we are able to show possible advantages of our 'Hybrid zoom lenses' over these widespread system types. Conclusions: We demonstrate important collinear considerations for the integration of tuneable lenses into a zoom lens. We show that the combination of classical zoom lens concepts with tuneable lenses offers the possibility to reach smaller system lengths for macroscopic zoom lenses while requiring only a small focal tuning range of the tuneable lens.

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“…They are of fundamental importance in the realising of novel beam-shaping and -guiding concepts for ultra-compact and powerful optical units for micro-and nanostructuring, which will be integrated into the NPMM in the framework of our research work. Innovative microtechnical methods and procedures can be combined to build efficient active optical modules which will offer high potential for future applications [69][70][71].…”

Section: Future Workmentioning

confidence: 99%

Towards alternative 3D nanofabrication in macroscopic working volumes

Kühnel

Fröhlich

Füßl

et al. 2018

Meas. Sci. Technol.

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This paper gives an overview of the research carried out at TU Ilmenau towards the development and application of tip- and laser-based nanofabrication on flat and curved surfaces in extended macroscopic working areas. It is shown that sub-10 nm structures can be fabricated by scanning probe lithography (SPL). The use of soft stamps has revealed their suitability for nanoimprinting on curved surfaces. Laser-based methods for a maskless exposure of resist on curved surfaces utilising 405 nm laser diodes have already been tested successfully. Furthermore, the current work deals with two-photon polymerisation, which has great potential with regard to the fabrication of sub-wavelength structures. At present, the methods mentioned have all been applied only in working ranges <100 × 100 μm2 in the plane and <10 μm in height. To overcome these limitations, the nanofabrication techniques are now being integrated in the nanopositioning and measuring machines (NPMMs) developed at TU Ilmenau. They offer working volumes of up to 200 × 200 × 25 mm3 with a positioning resolution of 20 pm. To provide access to any geometry elements in the 3D space with nanometre precision, the machine concepts as well as the metrological concepts are further developed. Due to the increased demands of lowest trajectory deviations within the fabrication process, new real-time controllers for probing and fabrication systems are investigated, as well as interactions in combined force and positioning sensors. Further important research is carried out into interference lithography, to enable an exposure of non-planar substrates and to improve the lateral structure resolution at the same time. A mix-and-match combination of such methods that allows the simultaneous exposure of large substrate regions with nanofabrication methods such as SPL becomes possible on the basis of the NPMMs, and is another area of great potential with regard to the research work presented in this paper.

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MOEMS tunable microlens made of aluminum nitride membranes

Cited by 10 publications

References 14 publications

Variation of the intrinsic stress gradient in thin aluminum nitride films

Variation of the intrinsic stress gradient in thin aluminum nitride films

Zoom systems with tuneable lenses and linear lens movements

Towards alternative 3D nanofabrication in macroscopic working volumes

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