Scientists of Fraunhofer ISIT have been working on the development of micro-electromechanical systems (MEMS) for over than 30 years now. In the Business Unit MEMS Applications, ISIT focuses on design, development, and production of MEMS components and MEMS systems.
Optical microsystems are a major focus in this business unit. ISIT develops vector scanners as well as resonant MEMS scanners including control and readout electronics for various types of laser projection displays, for optical measurement and detection systems (e.g. LIDAR), for applications with high laser power in the field of material processing and generative manufacturing as well as for the use in optical telecommunications.
Based on a patented manufacturing process, ISIT is currently the world's only manufacturer of two-axis, wafer-level vacuum-encapsulated resonant MEMS scanners. Operating these scanning micromirrors in a vacuum environment offers significant advantages. Damping by the gas molecules is reduced to a minimum, enabling high-frequency scanning with unrivaled scan angles even at low electrostatic driving voltages. Hermetic encapsulation at the wafer level also results in the cost-effective and permanent protection of the scanning micromirrors against all kinds of contamination. This for example makes the steam sterilization of these MEMS scanners in an autoclave for endoscopy applications possible without causing damage.
ISIT has also created a 3D camera with a depth resolution of just a few millimeters and a detectable object distance of 2 meters on the basis of 2D MEMS scanners. Novel scanning micromirrors with apertures of up to 2 centimeters and highly reflective coatings even permit highly dynamic dual-axis laser beam deflection for CW laser outputs of up to 500 watts.
In addition to capacitively driven resonant scanning micromirrors, ISIT also focuses on piezoelectrically driven vector scanners. These systems are characterized by a very high force-density combined with low energy consumption and allow quasi-static deflections of more than ±10°.
A further focal point in this business unit is acoustic microsystems. In this fast-growing field, ISIT is an international leader in research into innovative, highly miniaturized loudspeakers for applications in wearables, hearing aids, AR/VR, wireless headphones and smartphones. These MEMS loudspeakers are at least as good in acoustic quality as their conventional electrodynamic counterparts, but are significantly less expensive and can be fabricated even more miniaturized. Further advantages are the high energy efficiency and the high acoustic bandwidth (20 Hz - 100 kHz) of these components. This makes ISIT's chip-level loudspeakers particularly attractive for mobile communication devices such as tablets, smartphones, headphones and hearing aids in which high acoustic quality is required while at the same time further shrinking in size and low energy consumption.
Ultrasonic microsystems, e.g. for 3D distance measurements and haptic man-machine interfaces, are another research topic. Depending on the frequency range, the transducers at ISIT are usually designed as thickness-mode or membrane transducers with AlN, AlScN, or PZT as drive materials. Efficient ultrasound transducers with center frequencies of a few kHz to several hundred MHz can be realized this way.
Based on a manufacturing technology developed and patented at ISIT, the Agglomerated Microsystems group develops innovative microcomponents for applications in the fields of MEMS sensors and actuators, microfluidics, energy harvesting and haptic human-machine interfaces.
Fraunhofer ISIT has a patented agglomeration technology for the production of three-dimensional microstructures. The technology opens up numerous degrees of freedom for the realization of novel micro components with innovative functionalities. The type of materials as well as the geometry, porosity and inner surface of the agglomerated structures are used to set the desired properties. ISIT's manufacturing technology offers various advantages over other processes such as sintering or polymer-based binders: Low process temperatures and thermal stability are allowing a clean room compatible further processing of the components and the open pore structure allows microfluidic applications.
In addition to agglomeration technology, ISIT has extensive expertise and equipment for the realization of complete components. Pre- and post-processing by means of numerous clean room processes allow the optimal integration of agglomerated components for the improvement of existing or the realization of newly developed microsystems.