A low cross-sensitivity dual-axis silicon-on-insulator accelerometer integrated as a system in package with digital output

This paper introduces a novel dual-axis accelerometer structure with low cross-sensitivity. The device is fabricated in an SOI process, namely SOIMUMPs, and its fabrication is finalized by an in-house release step. The device measures 1 A— 1 mm2 with four proof masses that are able to sense accelerations in the X and Y axes independently. Two commercial capacitance-to-digital converters are used to read both axes outputs of the device in a system in package implementation. Simulations show a sensitivity of 25 fF/g and the fabricated device exhibits a sensitivity of 101 digital counts/g or 16.83 fF/g. The measured cross-sensitivity is <1 % throughout the 4 g linear range. The rotational motion and Z accelerations have no impact on the device X and Y readings, thanks to the particular geometry and differential nature of the device.