Development and application of planar piezoresistive vibration sensor

By using the surface piezoresistor diffusion method and front-side-releasing micromachining technique, we successfully developed a planar piezoresistive vibration sensor with less process cost, simple structure and less package difficulties. The functional features of the fabricated planar vibration sensors, including the amplitude-frequency response and random vibration response, have been evaluated comprehensively. As the results shown, the vibration sensor has reasonably good sensitivity performance (Min. detectable acceleration: 0.01 g at the Min. responsible frequency of 4 Hz; stable output at the measured signal with frequency >6 Hz and amplitude >0.05 g) for many applications: e.g. as the motion sensor for checking the health condition of human beings, or as the monitor sensor for monitoring the safety and security of infrastructure.