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J. Matovic:
"Stress control in bimaterial sensors and actuators";
Talk: 4M 2005 - First International Conference on Multi-Material Micro Manufacture, Forschungszentrum Karlsruhe, Deutschland; 06-29-2005 - 07-01-2005; in: "4M - First Interantional Conference on Multi-Material Micro Manufacture - Proceedings", J. Matovic (ed.); Elsevier, (2005), ISBN: 0-080-44879-8; 465 - 468.

The bimaterial cantilevers are frequently used in microsensors and microactuators. A bimaterial element consists of two layers of materials with different physical properties and/or deposited under different conditions. For this reasons, mechanical stresses of various origins appear along the layers and between them, causing initial deformation of the cantilever. Further, a necessary condition for the optimum response of a bimaterial cantilever to an external stimulus is that Young's moduli of both of the cantilever layers are approximately equal. In thermal cantilever-based actuators wgich are often met in practice, the first layer usually consits of SiO2, PolySi or SiNx, while the other is made from Al or Au. The Young's moduli of these materials differ significantly and thus the maximum sensitivity cannot be achived.
To ensure the planarity of the free cantilever, usually the goal during fabrication is to obtain low internal stresses within both layers, which sometimes represents a severe technological limitation in high-temperature processes. This work presents a new method of compensation of stresses between bimaterial cantilever layers. SiO2, PolySi or SiNx are still used for the first layer, while nickel is used for the second layer. Nickel has favorable mechanical properties and its Young's modulus is near to the materials form the first layer.

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05935936