In-plane acoustic reflectors for reducing effective anchor loss in lateral–extensional MEMS resonators

Harrington, Brandon P.; Abdolvand, Reza

doi:10.1088/0960-1317/21/8/085021

Cited by 144 publications

(69 citation statements)

References 37 publications

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“…Support losses can be reduced by using analytical and numerical models for stresswave radiation to guide the selection of materials, structures, dimensions, modes, and frequencies. Alternately, the generation and propagation of elastic waves can be disrupted by contacting the resonator at its nodal points using anchors or tethers [26][27][28][29][30][31] and incorporating phononic band-gap structures [32][33][34][35], acoustic reflectors [36,37], and vibration isolators [38,39]. In each case, well-established models from vibrations and elasticity are available to guide design.…”

Section: Elastic Wave Radiationmentioning

confidence: 99%

Design strategies for controlling damping in micromechanical and nanomechanical resonators

2014

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Damping is a critical design parameter for miniaturized mechanical resonators usedin microelectromechanical systems (MEMS), nanoelectromechanical systems (NEMS),optomechanical systems, and atomic force microscopy for a large and diverse set ofapplications ranging from sensing, timing, and signal processing to precisionmeasurements for fundamental studies of materials science and quantum mechanics.This paper presents an overview of recent advances in damping from the viewpointof device design. The primary goal is to collect and organize methods, tools, andtechniques for the rational and effective control of linear damping in miniaturizedmechanical resonators. After reviewing some fundamental links between dynamicsand dissipation for systems with small linear damping, we explore the space ofdesign and operating parameters for micromechanical and nanomechanicalresonators; classify the mechanisms of dissipation into fluid–structure interactions(viscous damping, squeezed-film damping, and acoustic radiation), boundarydamping (stress-wave radiation, microsliding, and viscoelasticity), and materialdamping (thermoelastic damping, dissipation mediated by phonons and electrons,and internal friction due to crystallographic defects); discuss strategies for minimizingeach source using a combination of models for dissipation and measurements of material properties; and formulate design principles for low-loss micromechanical and nanomechanical resonators

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Section: Elastic Wave Radiationmentioning

confidence: 99%

Design strategies for controlling damping in micromechanical and nanomechanical resonators

2014

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“…Practically, most conventional MEMS devices that used to be made out of silicon have recently been reproduced (in most cases with enhanced performance) by using AlN thin-fi lm piezoelectric technology. For example, resonators, [2][3][4][5] fi lters, [6][7][8] switches, [9][10][11] energy harvesters, [12][13][14] ultrasonic transducers, 15,16 microphones, 17,18 strain sensors, 19 chemical sensors, 20 and accelerometers 21 have been demonstrated using AlN thin fi lms. This article reviews MEMS development using AlN, with a particular focus on RF applications and the development of…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric aluminum nitride thin films for microelectromechanical systems

et al. 2012

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“…Several techniques to minimize anchor loss in microresonators have been reported in the literature, including the use of acoustic stop-band phononic crystal structures 28 , the addition of half-wavelength acoustic reflectors 29 , or the exploitation of the mismatch of material properties for acoustic isolation 30 . However, a less intricate way to isolate a resonant structure is including a stress isolation structure 31 .…”

Section: Mechanical Reduction Of Anisodampingmentioning

confidence: 99%

Substrate-decoupled, bulk-acoustic wave gyroscopes: Design and evaluation of next-generation environmentally robust devices

Serrano¹,

Zaman²,

Rahafrooz³

et al. 2016

Microsyst Nanoeng

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This paper reports on a new type of high-frequency mode-matched gyroscope with significantly reduced dependencies on environmental stimuli such as temperature, vibration, and shock. A novel stress-isolation system is used to effectively decouple an axis-symmetric bulk-acoustic wave (BAW) vibratory gyro from its substrate, minimizing the effect that external sources of error have on the offset and scale factor of the device. Substrate-decoupled (SD) BAW gyros with a resonance frequency of 4.3 MHz and Q values near 60 000 were implemented using the high aspect ratio poly and single-crystal silicon (HARPSS) process to achieve ultra-narrow capacitive gaps. Wafer-level packaged sensors were interfaced with a customized application-specific integrated circuit (ASIC) to achieve low variations in the offset across temperature (±26°s − 1 from − 40 to 85°C), supreme random-vibration immunity (0.012°s − 1 g RMS − 1 ) and excellent shock rejection. With a scale factor of 800 μV (°s, the SD-BAW gyro system attains a large full-scale range (±1250°s) with a non-linearity of less than 0.07%. A measured angle-random walk (ARW) of 0.39°/√h and a bias instability of 10.5°h − 1 are dominated by the thermal and flicker noise of the integrated circuit (IC), respectively. Additional measurements using external electronics show bias-instability values as low as 3.5°h INTRODUCTIONMicromachined gyroscopes have enabled a myriad of applications that range from basic motion detection for gaming to safety control systems in automobiles 1 . More recently, an increased interest in the use of microelectromechanical system inertial sensors for dead reckoning and pedestrian navigation in handheld electronics has placed stringent requirements on the die size, power consumption, and overall performance of this type of device. To date, most commercially available rate sensors have been designed as low-frequency flexural tuning-fork gyroscopes (TFGs), which are typically sensitive to random vibrations and prone to linear accelerations, such as those experienced under shock. These limitations complicate the use of TFG technology in large-volume, high-end applications, particularly in personal navigation, for which dependencies on fluctuations in the environment translate into long-term drift in the output of the system. Additionally, in recent months, concerns about the high sensitivity of consumer-grade gyroscopes in response to lowfrequency pressure signals that can be used to recover audio have increased as a potential threat for eavesdropping 2 , justifying the need for more environmentally robust rotation sensors.Acceleration suppression mechanisms can be implemented in TFGs to alleviate part of this problem using redundant proof masses that reject shock and vibration as common-mode signals 3 .

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In-plane acoustic reflectors for reducing effective anchor loss in lateral–extensional MEMS resonators

Cited by 144 publications

References 37 publications

Design strategies for controlling damping in micromechanical and nanomechanical resonators

Design strategies for controlling damping in micromechanical and nanomechanical resonators

Piezoelectric aluminum nitride thin films for microelectromechanical systems

Substrate-decoupled, bulk-acoustic wave gyroscopes: Design and evaluation of next-generation environmentally robust devices

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