CMOS-MEMS Microgravity Accelerometer with High-Precision DC Response

In this Phase II SBIR project a high-sensitivity low-noise all-silicon CMOS-MEMS accelerometer for quasi-steady measurements of accelerations at sub 1 micro-g levels will be developed. The outcome of the project is a capacitive microaccelerometer with a resolution of 90ng/sqrt-Hz over +/-0.1g range for Type A sensor and 0.8ug/sqrt-Hz over +/-1g for Type B sensor with programmable bandwidth from DC to programmable 0.1Hz-100Hz. The accelerometer module includes integrated low-noise CMOS circuitry with active offset and low-frequency noise cancellation to enable high-precision DC measurements. The high-performance of the sensor is enabled by innovation in both MEMS accelerometer and readout circuit technologies: i) Single-crystalline silicon capacitive accelerometer structure. The device has high sensitivity and low thermo-mechanical noise; ii) Innovative high-yield fabrication process that enables formation of high-sensitivity devices on top of CMOS wafers; iii) New and improved low-noise capacitive sensor readout CMOS circuit. This novel microaccelerometer has several NASA applications including measurement of residual accelerations on spacecraft and ground-based low-gravity facilities.