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The invention relates to a sensor for determining the temperature in the contact zone situated between two bodies which are in contact and which can move in relation to one another, especially the contact zone between a grinding wheel (2) and a workpiece during grinding. The inventive sensor comprises a thermoelement which has two electric leads and which is provided for generating an electric voltage that corresponds to the temperature to be determined. According to the invention, the thermoelement is arranged inside one of both bodies, and the leads are interspaced in a close manner. From the contact surface of the body, said leads extend into the body and, during operation, are re-contacted and/or re-welded in the contact zone situated between the bodies by means of frictional heat.

Because of a steadily growing demand of low-cost gas sensors for use in automotive applications, for environmental monitoring and for quality control a resistive gas sensor array has been developed with microsystem technologies. At first a calculation and a valuation of the expected power consumption for a membrane gas sensor in comparison to a gas sensor without a membrane structure has been conducted. One of the results is, when using membrane structures and minimising the sensor dimensions power consumption can be reduced to a few percents of the primary value. For the realisation of the membrane gas sensor a process flow has been developed which uses a thick porous silicon sacrificial layer. The crucial point of the investigations was finding a masking layer technology to realise local defined porous silicon wells.Two of the most important reasons for using porous silicon are the thickness of the sacrificial layer (in a range between 5 µm and 100 µm) and the possibility to remove the sacrificial layer on wafer level after the chip dicing process.Because of the membrane approach locating several single sensors on the same chip without influencing each other is possible. Because of the low thermal capacity of each single membrane the sensors are able to change their working temperature very fast (within few ms). The developed sensor substrates have been combined with the sensitive material SnO:sub:2:/sub: and have been characterised in special test gas situations. When exposing the sensors to CO, NO:sub:2:/sub: or humidity a big change in the sensor signal can be observed. Using a combination of two equal single sensors (a sensor array) and making them work on different temperatures detecting a 2-component gas mixture of CO and NO:sub:2:/sub: without any problems is possible. Using the developed sensor substrate in combination with other sensitive materials than tindioxide would enable us to use the sensor system to detect other gases.

The subject of this thesis is the development of new micromechanical switches as MEMS (Micro Electro Mechanical Systems) products for use in a variety of communication-applications.The research work performed within the frame of this thesis on the ´RF-switch´ (radio-frequency switch) is used to demonstrate the importance of an ´integrated design and development approach´ for a product-development. The successful realization, not only from a technological but also from an economic perspective, can only be achieved by considering all aspects of production for the entire end-to-end process, starting with the definition of the initial device-concept. Therefore an optimized integration of the front-end of line (FE-) processing and the back-end of line (BE-) processing together with the device packaging at the very end of the fabrication sequence has to be realized.The RF-switches are produced using a newly developed semiconductor process combination. First a poly-Si surface micromachining (SMM) process is used to create the mechanical switch-structure. Afterwards the special metal contacts are formed using additive electroplating technology (AET) in order to establish the electrically functional switch. The switch-element is then protected from the environment with a waferlevel-packaging scheme, before the individual device can be mounted into an SMD-package.The scientific focus of this thesis is marked by the device-concept for the RF-switch and the development of the end-to-end production process within the fab. The development of newly designed processing steps was required for this, which also included the challenging task of integrating these individual processing clusters and steps with each other within the production line. An analysis and characterization of the fabricated devices demonstrates the successful production capability. A discussion of the promising growth-potential for MEMS-products and RF-switches in particular is included in the appendix.