Eight-beam piezoresistive accelerometer fabricated by using a selective porous silicon etching method

This paper presents the first experimental results of a piezoresistive silicon accelerometer with eight beams fabricated by a unique silicon micromachining technique using selective porous silicon etching. This technique is capable of precisely constructing a microstructure without any lateral etching or undercutting. By the use of eight-beam structure, the mechanical strength of the accelerometer can be highly improved due to smaller shear stress. The lower sensitivity of the sensor can be simply solved by combining four output signals of half-bridge. The effectiveness of the sensor is confirmed through an experiment in which the accelerometer is characterized.