A monolithic 9 degree of freedom (DOF) capacitive inertial MEMS platform

Ocak, Ilker Ender; Cheam, Daw Don; Fernando, Saman; Lin, Angel Tsu-Hui; Singh, Pushpapraj; Sharma, Jaibir; Chua, Geng Li; Chen, Bangtao; Gu, Yuandong; Singh, Navab; Kwong, Dim‐Lee

doi:10.1109/iedm.2014.7047103

Cited by 13 publications

(6 citation statements)

References 8 publications

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“…Electroplating mitigates the disadvantage of surface micromachining by increasing the thickness of the structure. There are also reported developments for monolithically fabricating a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer in a single chip [ 25 , 26 ].…”

Section: Types Of Accelerometersmentioning

confidence: 99%

Monolithic Multi Degree of Freedom (MDoF) Capacitive MEMS Accelerometers

2018

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With the continuous advancements in microelectromechanical systems (MEMS) fabrication technology, inertial sensors like accelerometers and gyroscopes can be designed and manufactured with smaller footprint and lower power consumption. In the literature, there are several reported accelerometer designs based on MEMS technology and utilizing various transductions like capacitive, piezoelectric, optical, thermal, among several others. In particular, capacitive accelerometers are the most popular and highly researched due to several advantages like high sensitivity, low noise, low temperature sensitivity, linearity, and small footprint. Accelerometers can be designed to sense acceleration in all the three directions (X, Y, and Z-axis). Single-axis accelerometers are the most common and are often integrated orthogonally and combined as multiple-degree-of-freedom (MDoF) packages for sensing acceleration in the three directions. This type of MDoF increases the overall device footprint and cost. It also causes calibration errors and may require expensive compensations. Another type of MDoF accelerometers is based on monolithic integration and is proving to be effective in solving the footprint and calibration problems. There are mainly two classes of such monolithic MDoF accelerometers, depending on the number of proof masses used. The first class uses multiple proof masses with the main advantage being zero calibration issues. The second class uses a single proof mass, which results in compact device with a reduced noise floor. The latter class, however, suffers from high cross-axis sensitivity. It also requires very innovative layout designs, owing to the complicated mechanical structures and electrical contact placement. The performance complications due to nonlinearity, post fabrication process, and readout electronics affects both classes of accelerometers. In order to effectively compare them, we have used metrics such as sensitivity per unit area and noise-area product. This paper is devoted to an in-depth review of monolithic multi-axis capacitive MEMS accelerometers, including a detailed analysis of recent advancements aimed at solving their problems such as size, noise floor, cross-axis sensitivity, and process aware modeling.

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Section: Types Of Accelerometersmentioning

confidence: 99%

Monolithic Multi Degree of Freedom (MDoF) Capacitive MEMS Accelerometers

2018

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“…The magnetometer resonator device that is modeled in this work has been designed and fabricated using the MEMS motion-sensing platform developed at the A*STAR Institute of Microelectronics (IME), Singapore [35]. The structure shown in figure 2 is the rotor part of a Lorentz force magnetometer device.…”

Section: Magnetometer Computational Modelmentioning

confidence: 99%

Numerical modeling and validation of squeezed-film damping in vacuum-packaged industrial MEMS

Syed

Brimmo

Waheed

et al. 2017

J. Micromech. Microeng.

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Several high-performance, industrial micro-electromechanical (MEM) devices, such as gyroscopes, magnetometers, high-Q resonators and piezoelectric energy harvesters, require wafer bonding and packaging under near-vacuum conditions. One very challenging aspect of the design, verification and characterisation of these devices is to predict their performance characteristics in the presence of any residual gases post-packaging. Such gases contribute to the energy losses resulting from device surfaces squeezing or sliding against the gas films within the device cavities. In this paper, we fully expose the modelling assumptions used in commercial FEM tools to estimate the squeezed-film damping (SFD) experienced by MEM devices that are packaged under near-vacuum conditions. We also explain the various meshing options to enable the extraction of the most accurate Q factors under existing SFD assumptions. In addition, we compare the computational results across a variety of commercial FEM codes against measurements obtained under realistic vacuum conditions for an industrial high-Q magnetometer. These measurements suggest that existing computational models may deviate by as much as 25% on Q factor values for gas flow regimes under operating cavity pressures of less than 1 Torr.

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“…In order to achieve a small-footprint, multiple-functionality, and cost-effective sensor node for emerging internet of things (IoT) and body area networks (BAN) applications, the multi-sensor platform becomes a promising solution to integrate multi-degree of freedom (MDOF) inertial measurement units (IMU) [1] and versatile environmental sensors [2] on the same chip. Fig.…”

Section: Introductionmentioning

confidence: 99%

Transduction comparison of a resonant transducer realized in a commercially available CMOS-MEMS platform

Chen

Wang

et al. 2015

2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS)

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In this paper, we report the comparison of different transduction mechanisms, including (i) purely capacitive drive/sense, (ii) capacitive drive/piezoresistive sense, and (iii) thermal drive/piezoresisitve sense, through a simple resonant transducer achieved in a commercially available platform (CMOS 0.18μm technology). To perform a fair comparison, capacitive combs and poly resistors are adopted to provide various combinations of the drive and sense configurations. The experimental results show performance of the thermal drive/piezoresistive sense is superior to that of other transductions under a typical circuit biasing (1.8V). By characterizing randomly picked 8 samples, the 1-σ frequency variation is lower than 4,800 ppm with total drive/sense power consumption below 0.67 mW through the (iii) scheme. Moreover, a high Q-factor of 200 is also measured in air (under 760 Torr), which successfully demonstrates its great potential for future portable sensor nodes application.

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A monolithic 9 degree of freedom (DOF) capacitive inertial MEMS platform

Cited by 13 publications

References 8 publications

Monolithic Multi Degree of Freedom (MDoF) Capacitive MEMS Accelerometers

Monolithic Multi Degree of Freedom (MDoF) Capacitive MEMS Accelerometers

Numerical modeling and validation of squeezed-film damping in vacuum-packaged industrial MEMS

Transduction comparison of a resonant transducer realized in a commercially available CMOS-MEMS platform

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