Abstract: To form an isolation structure in a semiconductor substrate, at least two trenches are formed with a rib therebetween in the semiconductor substrate, and then the semiconductor material in the area of the trenches and particularly the rib is converted to an electrically insulating material. For example, this is accomplished by thermal oxidation of silicon semiconductor material of the rib.

Abstract: The invention relates to processes for the formation of isolation structures for micro-machined sensors in single-crystal surface technology. In known processes, silicon structures defined by deep trenches are etched and uncovered by a “release etch” step also at their bottom surface towards the substrate. The subsequent lining of these trenches with a non-conducting insulating material, such as silicon dioxide leads to a firm anchoring by means of a surrounding of the silicon structure with the lined trenches on three sides, leaving one side uncovered. It is the main idea of the invention—instead of lining the trenches—to convert thin-walled silicon into an electrically non-conducting material. This can, for instance, be accomplished by means of a thermal oxidation of narrow silicon ribs released prior thereto by trenches. In the minimal configuration, two trenches (holes) per rib with the required structure depth must be etched for this purpose.

Abstract: A self-testing sensor (especially to measure an angular rate or acceleration) includes a resonant structure, an actor unit configured to excite the structure to a first periodic vibration, a piezoresistive element configured to generate an output signal that depends on the measured quantity, and an isolator configured to isolate a test signal component from the output signal, whereby the test signal component is generated by a second periodic vibration of the structure superposed on the first vibration. A device for self-testing a sensor includes an isolator configured to isolate a test signal component superposed on a useful signal component from the periodic output signal of the sensor, and it includes a comparator configured to compare the test signal component with a predefined value or a test signal fed to the sensor. For the self-test, a second periodic vibration is superposed on a first vibration of the structure, and an output signal containing information on the measured quantity is determined.

Abstract: A microsensor with a resonator structure, which is excited by first electrical signals to oscillate and emits second electrical signals in dependence on the measuring variable, wherein a heating element, supplied with at least one of the first electrical signals, is arranged on the resonator structure for the thermal excitations of oscillations. For the thermal excitation of lateral oscillations in a microsensor with a resonator structure, the microsensor is provided at one oscillating part of the resonator structure with at least two regions that are thermally separated by a zone with reduced heat conductance, and the heating element is arranged on one of the regions. This type of arrangements permits the excitation of the resonator structure to lateral oscillations if the heating element is supplied with corresponding current pulses. It is advantageous if a receiving element is arranged on at least one of the other regions to detect the oscillation amplitude.