In recent years, miniaturised acceleration sensors have become increasingly important. These are micro-electro-mechanical systems (MEMS) and are usually made of silicon. These sensors are spring-mass systems in which the “springs” are silicon bars only a few μm wide and the mass is also made of silicon. Due to the deflection during acceleration, a change in electrical capacitance can be measured between the spring-mounted part and a fixed reference electrode. The entire measuring range corresponds to a capacitance change of approx. 1 pF. The electronics for analysing this small change in capacitance are housed on the same integrated circuit (IC).
There are also variants in which piezoresistive resistors are attached to the bending beam by ion implantation, which change their resistance according to the bending and thus allow conclusions to be drawn about the acceleration.