A low-voltage bulk-silicon tunneling-based microaccelerometer

This paper describes the design, fabrication, and testing of a low-driving-voltage (/spl les/10 V) bulk-silicon tunneling-based microaccelerometer. Using the bulk-silicon fabrication technology and boron etch-stop dissolved wafer process, one of the devices with an active area of 400/spl times/400 /spl mu/m/sup 2/ has been successfully fabricated, fully characterized, and electrostatically tested. The d.c. sensitivity is 1.66/spl times/10/sup 4/ ppm/g (133 mV/g) and the gain bandwidth is 2 kHz in air. The device provides a full scale range of -20 g to 10 g with a nonlinearity of 0.6%. The measured sensitivity variation is /spl plusmn/150 ppm per g (/spl ap/0.9%) over three weeks, which is primarily attributed to the change of tip characteristics and creep of microstructures over time. The temperature coefficient of offset (TCO) and temperature coefficient of sensitivity (TCS) are -600 ppm//spl deg/C and 1200 ppm//spl deg/C respectively.