Development and application of planar piezoresistive vibration sensor

A high performance planar piezoresistive vibration sensor with less process cost, simple structure and less package difficulties. A micromachined planar piezoresistive vibration sensor has been developed.The sensor was fabricated with less process cost and difficulties in packaging.Vibration sensor exhibited performance comparable to a commercial sensor device. 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: 0.01g at the Min. responsible frequency of 4Hz; stable output at the measured signal with frequency >6Hz and amplitude >0.05g) 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.