A skew-symmetric cantilever accelerometer for automotive airbag applications

A piezoresistive cantilever-beam microaccelerometer has been designed, fabricated and tested with a hybrid airbag electronic control unit for automobile crash detection. A skew-symmetric accelerometer has been proposed and the associated fabrication process has been developed. A simultaneous etching process for beam-thickness control, fillet-rounding formation and corner compensation is discussed. The microfabricated device shows a flat response with a resonance frequency of 2.07 kHz and a sensitivity of 65 mu V g(-1) V-1. A sensitivity of 67 mV g(-1) has been measured from the assembled unit with a non-linearity of 4%. The present skew-symmetric design and associated fabrication methods provide effective means for improving the robustness and reliability, as well as the transverse sensitivity of cantilever-beam accelerators.