Sub-1G MEMS accelerometer

This paper reports a sub-1G detectable MEMS accelerometer formed by the multilayer metal intended for post-CMOS process. High density of gold enables to minimize the footprint of the proof mass without compromising the sensitivity subjected to thermal-mechanical noise. The requirements of a low-G accelerometer have been studied in terms of the fabrication process and the device structure. The Brownian noise of the accelerometer is designed to be 2.24 μg/√Hz (at RT) for a proof mass of 1020 μm × 1020 μm × 12 μm, and the estimated actual value is 5.44 μg/√Hz. Sub-1G sensing has also been demonstrated by measuring the capacitance shift as a function of the input acceleration.