Sub nm-Resolution Static Measurement with MEMS Displacement Sensors

Todorov, Vencislav; Stavrov, Vladimir; Kreuter, Johann

doi:10.1016/j.proeng.2011.12.147

Cited by 8 publications

(2 citation statements)

References 2 publications

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“…In the dynamic mode, mass variation is detected by measuring the shifts in a natural, resonant or bifurcation frequency of the structure. The structural response is measured optically [4][5][6], piezoresistively [7,8] or capacitively [9]. However, most high-resolution sensors rely on optical detection [9].…”

Section: Introductionmentioning

confidence: 99%

Binary MEMS gas sensors

Khater

Al‐Ghamdi

Park

et al. 2014

J. Micromech. Microeng.

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A novel sensing mechanism for electrostatic MEMS that employs static bifurcation-based sensing and binary detection is demonstrated. It is implemented as an ethanol vapour sensor that exploits the static pull-in bifurcation. Sensor detection of 5 ppm of ethanol vapour in dry nitrogen, equivalent to a detectable mass of 165 pg, is experimentally demonstrated. Sensor robustness to external disturbances is also demonstrated. A closed-form expression for the sensitivity of statically detected electrostatic MEMS sensors is derived. It is shown that the sensitivity of static bifurcation-based binary electrostatic MEMS sensors represents an upper bound on the sensitivity of static detection for given sensor dimensions and material properties.

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Section: Introductionmentioning

confidence: 99%

Binary MEMS gas sensors

Khater

Al‐Ghamdi

Park

et al. 2014

J. Micromech. Microeng.

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“…Microelectromechanical System (MEMS) nanopositioners have attracted significant interest recently because of their small size, low cost, fast dynamics and the emergence of applications such as probe-based data storage [12,13], and scanning probe microscopy [14,15,16]. Closed-loop feedback control of these positioners is highly desirable if a high degree of displacement precision is required, and such a control system needs an accurate source of position information [17,18,19,20]. However, many of the MEMS nanopositioners reported in the literature are not equipped with on-chip sensors due to the restrictions associated with micro-fabrication processes [21,22,23].…”

Section: Introductionmentioning

confidence: 99%

Control Issues of MEMS Nanopositioning Devices

Zhu

Moheimani

Yuce

et al. 2016

Nanopositioning Technologies

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In this chapter, the control issues of Microelectromechanical System (MEMS) nanopositioning devices are introduced and discussed. The real-time feedback control of a novel micro-machined 1-degree-of-freedom (1-DoF) thermal nanopositioner with on-chip electrothermal position sensors is presented. The actuation works based on thermal expansion of V-shaped silicon beams. The sensing mechanism works based on measuring the resistance difference between two electrically biased identical silicon beams. The resistance difference varies with displacement. The heat conductance of the sensor beams varies oppositely with the position of the movable stage, resulting in different beam temperatures and resistances. A pair of position sensors are operated in differential mode to reduce low-frequency drift. The micromachined nanopositioner has a nonlinear static input-output characteristic. The electrothermal actuator has a dynamic range of 14.4 µm and the electrothermal sensor has a low drift of 8.9 nm over 2000 seconds. An open-loop controller is first designed and implemented. It is experimentally shown that uncertainties result in unacceptable positioning performance. Hence, feedback control is required for accurate positioning. The on-chip displacement sensor is able to provide high-resolution displacement control. Therefore, a real-time closed-loop feedback control system is designed using a proportional-integral (PI) controller together with the nonlinear compensator used for the open-loop control system. The closed-loop system provides acceptable and robust tracking resolution for a wide range of set point values. The step response results show a positioning resolution of 7.9 nm and a time constant of 1.6 ms in a 10 µm stroke. For triangular reference tracking, which is required in raster-scanned Scanning Probe Microscopy (SPM), the steady-state tracking error has a standard deviation of 20 nm within a wide range of 10 μm.

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