CMOS Circuits for MEMS Aluminum Nitride Inertial Sensors (MINT)
Bernhard Boser, Richard Przybyla and Igor Izyumin
Defense Advanced Research Projects Agency N66001-08-C-2023 and Space and Naval Warfare Center
Aluminum Nitride (AlN) is a piezoelectric material that has gained widespread use in filters for mobile phones. However, AlN is also a promising material for use in MEMS sensors because of its mechanical properties and low temperature, CMOS-compatible deposition. In this project, we are working with multi-disciplinary team to develop AlN micromachined ultrasound transducers  (See Fig. 1), AlN accelerometers, and AlN gyroscopes. The piezoelectric properties of the material yield performance benefits over the standard, electrostatic MEMS because they do not require bulky comb drives and do not suffer the same non-linearities. In the last two years, we have demonstrated an AlN accelerometer, a velocity sensor with sub-mm/sec resolution based on an AlN ultrasound transducer, a MEMS rangefinder with nearly 50cm range , and a MEMS ultrasonic distance sensor with a range >1 meter and sub-mm local resolution (which is shown in Fig. 2).
Figure 1: Optical micrograph of piezoelectric micromachined ultrasound transducer
- S. Shelton, M.-L. Chan, H. Park, D. Horsley, B. Boser, I. Izyumin, R. Przybyla, T. Frey, M. Judy, K. Nunan, F. Sammoura, and K. Yang, “CMOS-compatible AlN piezoelectric micromachined ultrasonic transducers,” in Proc. IEEE Ultrasonics Symp. 2009, Oct. 2009, pp. 402–405.
- R. Przybyla, S. Shelton, A. Guedes, I. Izyumin, M. Kline, D. Horsley, and B. Boser, “An ultrasonic rangefinder based on an AlN piezoelectric micromachined ultrasound transducer,” in Proc. IEEE Sensors 2010, Nov. 2010, pp. 2417–2421