This review provides a comprehensive survey of noise research in MEMS. Some background on noise and on MEMS is provided. We review noise production mechanisms, and highlight work on the theory and modeling of noise in MEMS. Then noise measurements in the specific types of MEMS are reviewed. Inertial MEMS (accelerometers and angular rate sensors), pressure and acoustic sensors, optical MEMS, RF MEMS, surface acoustic wave devices, flow sensors, and chemical and biological MEMS, as well as data storage devices and magnetic MEMS, are reviewed. We indicate opportunities for additional experimental and computational research on noise in MEMS.

Noise in MEMS

The bias drift of a micro-electro-mechanical systems (MEMS) accelerometer suffers from the 1/f noise and the temperature effect. For massive applications, the bias drift urgently needs to be improved. Conventional methods often cannot address the 1/f noise and temperature effect in one architecture. In this paper, a combined approach on closed-loop architecture modification is proposed to minimize the bias drift. The modulated feedback approach is used to isolate the 1/f noise that exists in the conventional direct feedback approach. Then a common mode signal is created and added into the closed loop on the basis of modulated feedback architecture, to compensate for the temperature drift. With the combined approach, the bias instability is improved to less than 13 μg, and the drift of the Allan variance result is reduced to 17 μg at 100 s of the integration time. The temperature coefficient is reduced from 4.68 to 0.1 mg/°C. The combined approach could be useful for many other closed-loop accelerometers.

A combined modulated feedback and temperature compensation approach to improve bias drift of a closed-loop MEMS capacitive accelerometer

Low frequency noise measurement and analysis of capacitive micro-accelerometers

Noise and reliability measurement of a three-axis micro-accelerometer

In this work, a noise measurement of capacitive micro-accelerometers incorporating temperature effect is presented. In the setup, a hot plate is used to heat the device up to temperatures in the 75 degree C range. A thermo couple attached to the enclosure is used to assess its temperature. The data show that the noise power increases at high temperature, but not as significant as predicted by the theory.

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Low Frequency Noise Measurement and Analysis of Capacitive Micro-Accelerometers: Temperature Effect

The noise characterization of a capacitive servo-accelerometer using a linear model is presented in this paper. The input reference noise of electronic circuit is expressed as a capacitive variation and it is introduced to a linear model for frequency response, separately with the thermal mechanical noise. The simulated noise was generally found to conform to the measured noise in the experiment, suggesting that the model can be effectively used for noise evaluation of accelerometers fabricated in a similar fashion.

Hideaki Kakuma

Papers

A linear model based noise evaluation of a capacitive servo-accelerometer fabricated by MEMS