S. Gautsch

Atomic force microscope for planetary applications

We have developed, built and tested an atomic force microscope (AFM) for planetary science applications, in particular for the study of Martian dust and soil. The system consists of a controller board, an electromagnetic scanner and a micro-fabricated sensor-chip. Eight cantilevers with integrated, piezoresistive deflection sensors are aligned in a row and are engaged one after the other to provide redundancy in case of tip or cantilever failure. Silicon and molded diamond tips are used for probing the sample. Images can be recorded in both, static and dynamic operation mode. In the latter case, excitation of the resonance frequencies of the cantilevers is achieved by vibrating the whole chip with a piezoelectric disk.

Microcolumn design for a large scan field and pixel number

A different approach in microcolumn design is presented, aiming at a large number of pixels at minimal probe size for the deflected beam. An optimization routine resulted in a seven times magnifying column featuring a more than 7×7mm2 scan field at 40mm working distance. Simulations for 1keV electrons from a field emission source predict an increase in beam size from 85nm on axis up to only about 200nm for a beam deflected 3mm off axis. Within a 1mm scan field this microcolumn could address over 100Mpixels of less than 100nm in size. Tests of this design using the 130nm electron probe of a scanning electron microscope as the electron source resulted in a beam size of ∼930nm on axis up to ∼1000nm for a beam deflected 3mm off axis.

Microsystems for diverse applications using recently developed microfabrication techniques

The continuous progress in micro- and nano-system technologies has allowed the successful development of many innovative products in process control, environmental monitoring, healthcare, automotive and aerospace as well as information processing systems. In this paper on overview will be given of current progress in micro- and nanofabrication process technologies, such as deep reactive ion etching, micro-electro discharge machining, thick photoresistant processing and plating. The availibility of these micro- and nanofabrication processes will be illustrated with examples of new generations of silicon-based sensors, actuators and Microsystems with a particular emphasis on real applications of these components and systems.

Micro-electromechanical Systems for Nano-science

Micro-electromechanical systems are ideal tools for nano-science because they bridge the gap between the nano- and the macro-world. Moreover, several of these instruments can be operated in parallel to either increase the throughput or to provide redundancy. The majority of the components of such a system have dimensions above the nanometer scale. Still, some require placement and pattern accuracy well below this limit. This will be highlighted in a short review of a few examples: Scanning optical near field microscope probe fabrication, where an aperture of 50 nm in diameter was incorporated at the probing tip; parallel scanning force microscope for measuring dust particles on Mars where redundancy is essential; and a miniaturized electron column for parallel electron beam lithography, where the throughput needs to be increased.

Tunable microcavities in two dimensional photonic crystal waveguides

In this work, we investigate the transmission properties of tunable resonant cavities inside photonic crystal waveguides. We present an optical and a mechanical way of perturbing the optical environment near the resonant cavity enabling tuning and modulation of the in-plane transmission. We have discussed different ways that change the transmission properties of cavities in photonic crystals. Optical switching and wavelength tuning is obtainable by means of induced thermo and electro optical effects. These results indicate the feasibility of high-speed optical integrated circuits based on silicon photonic crystal structures. In addition, simulations have shown that an AFM tip can be used for tuning and damping. These results suggest a stand-alone MEMS solution to create a chip-based on-off switch or tunable filter. Furthermore, one could attempt to integrate more than one silicon tip to combine filter and tuning functionalities on one device. By separately controlling the position of the different tips a programmable integrated optical circuit with higher integration density and functionality could be achieved

Fabrication of nano interdigitated electrodes

Thin-film Pt nano interdigitated electrodes realized by combining e-beam lithography and standard photolithography are presented. The resulting nano-IDAs have an active area of 76 μm × 100 μm, an electrode pitch of 785 nm and a gap of 250 nm. The initial results show that this technology is well adapted for the realization of sub-micrometer metallic structures.