Sub-Micron Mems Accelerometer with Handle-Layer Patterning for Damping Enhancement Using Time Transduction

A very high-resolution SOI (silicon-on-insulator) MEMS (Micro-Electro-Mechanical Systems) accelerometer for geodetic space grade applications using pull-in time measurements is presented here. Parallelplates implemented in the handle-layer are used to provide the necessary squeeze-film damping, while increasing the effective-mass. Large mass (126 mg) devices with low-Q (quality factor of 0.53) have been fabricated and tested using time transduction. The high measured sensitivity of 1.9 ns/ng enables the use of the device in ultra-high resolution and low-dynamic range applications.