Fall 2010 IAB
September 15 to 17
Post-CMOS Compatible Aluminum Nitride Accelerometer
Aluminum nitride (AlN) doubles as the structural material and the transducer in our post-CMOS bulk micromachined inertial and Doppler velocity sensors. A disc accelerometer with 1.5mm diameter and 460μ-gram proof mass has a first resonance at 2.6kHz and charge sensitivity of 72fC/g (1g=9.8m/s2). The Brownian noise is 120ng/rt-Hz; however, the noise is dominated by the electronic noise from the front-end amplifier. The resulting spot noise is 60μg/rt-Hz at 1kHz.
The piezoelectric interface provides an intrinsically ac-coupled measurement; however, the resonant frequency of the device varies with acceleration. In the resonant detection mode, the resonant frequency is monitored and the device measures acceleration down to dc with 3840ppm/g sensitivity.