Low-Power Resonant Acceleration Switch for Unattended Sensor Wake-Up

Cook, Eugene H.; Tomaino-Iannucci, Michael J.; Reilly, Daniel P.; Bancu, Mirela G.; Lomberg, Perri R.; Danis, Jason A.; Elliott, Richard D.; Ung, Jonathan S.; Bernstein, J.; Weinberg, Marc S.; Duwel, Amy

doi:10.1109/jmems.2018.2867282

Cited by 11 publications

(8 citation statements)

References 16 publications

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“…It is therefore important to keep a certain level of EtOH vapor during etching to bind the water to an unreactive byproduct. [ 37 ] This has to be considered in the selection of the etch gas composition. It remains to be determined to what extent byproducts can diffuse out of underlying cavities.…”

Section: Resultsmentioning

confidence: 99%

Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures

Burgmann¹,

Lid²,

Chaikasetsin

et al. 2022

Adv Eng Mater

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Nanoscale free‐standing membranes are used for a variety of sensors and other micro/nano‐electro‐mechanical systems devices. To tune performance, it is indispensable to understand the limits of aspect ratios achievable. Herein, vapor hydrofluoric (VHF) processes are employed to release 3D shell structures made of atomic‐layer‐deposited Al2O3 etch‐stop layers. Structure heights of 100–600 nm and widths of 1–200 nm are fabricated for membranes with 20 and 50 nm thickness. Undercut depths of and aspect ratios of 475:1 etch depth to structure width (50 nm films) and etch depth to membrane thicknesses of 495:0.02 (20 nm films) are achieved. The etch‐rate stagnates above a ratio of 31% hydrofluoric (HF), where decreasing EtOH shares reduce reproducibility. Etch rates reach 0.75 mm min−1 and are generally constant over vapor etch depth. For 100 nm heights and widths of , etch rates however stagnate for deeper depths. All explored structures remained stable with widths up to 5 μm independent of the height. Above width, top membranes deflect, likely from stress accumulated during deposition. Herein, exploring and understanding the limits of aspect ratio in future free‐standing membrane devices are helped.

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Section: Resultsmentioning

confidence: 99%

Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures

Burgmann¹,

Lid²,

Chaikasetsin

et al. 2022

Adv Eng Mater

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show abstract

“…Due to the finite bandwidth of the antenna, some of the higher frequency components of the OOK signal may be attenuated or missed, thereby limiting the bit rate of the resoswitch. In addition to radio frequency signal reception, the concept of resoswitches was also applied for other ultra-low power wakeup physical sensors, including acoustic wake-up switches of [45] and acceleration wake-up switch of [46].…”

Section: Vibro-impact Resonators and Resoswitches (Resonant Switches)mentioning

confidence: 99%

“…One prominent example is atomic force microscopy (AFM) [14][15][16][17][18][19][20][21] that uses probe tips as small as a few nanometers achieved by MEMS processes to measure interaction forces between the tip and the contact surface at the atomic level. Other examples of microscale vibro-impact systems include impact actuators [22][23][24][25][26], energy harvesters [27][28][29][30] with frequency up-conversion mechanism [31][32][33][34][35][36], RF switches [37][38][39], and resoswitches [40][41][42][43][44][45][46][47][48][49]. Each of these devices harnesses different aspects of impact-induced characteristics.…”

Section: Introductionmentioning

confidence: 99%

Micromechanical vibro-impact systems: a review

Tsai

2023

J. Micromech. Microeng.

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Spurred by the invention of the tapping-mode atomic force microscopy three decades ago, various micromechanical structures and systems that utilize parts with mechanical impact have been proposed and developed since then. While sharing most of the dynamical characteristics with macroscopic vibro-impact systems and benefiting from extensive theories developed, microscale counterparts possess higher percentage of surface force, higher resonance frequency and Q, and more prominent material and structural nonlinearities, all of which lead to unique features and in turn useful applications not seen in macroscopic vibro-impact systems. This paper will first present the basics of vibro-impact systems and techniques used for analyzing their nonlinear behaviors and then review the contact force modeling with an emphasis in microscale and numerical analysis tools. Finally, various applications of microscale vibro-impact systems will be reviewed and discussed. This review aims to provide a comprehensive picture of MEMS vibro-impact systems and inspire more innovative applications that take full advantage of the beauty of nonlinear vibro-impact dynamics in the microscale.

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“…By adopting the wake-up strategy, most of the wasted power is conserved, and the power efficiency is significantly improved, which greatly extends the battery life of the microsystem [ 4 ]. Different types of signals are used for event detection in wake-up microsystems, such as acoustic, mechanical, magnetic, optical, infrared, RF, et al [ 5 , 6 , 7 , 8 , 9 , 10 ]. Among them, the acoustic signal has the advantages of strong universality, long monitoring distance, rich data information, and abundant acoustic sensors.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Wake-Up Technology for Microsystems: A Review

Yang

Zhao

2023

Micromachines

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Microsystems with capabilities of acoustic signal perception and recognition are widely used in unattended monitoring applications. In order to realize long-term and large-scale monitoring, microsystems with ultra-low power consumption are always required. Acoustic wake-up is one of the solutions to effectively reduce the power consumption of microsystems, especially for monitoring sparse events. This paper presents a review of acoustic wake-up technologies for microsystems. Acoustic sensing, acoustic recognition, and system working mode switching are the basis for constructing acoustic wake-up microsystems. First, state-of-the-art MEMS acoustic transducers suitable for acoustic wake-up microsystems are investigated, including MEMS microphones, MEMS hydrophones, and MEMS acoustic switches. Acoustic transducers with low power consumption, high sensitivity, low noise, and small size are attributes needed by the acoustic wake-up microsystem. Next, acoustic features and acoustic classification algorithms for target and event recognition are studied and summarized. More acoustic features and more computation are generally required to achieve better recognition performance while consuming more power. After that, four different system wake-up architectures are summarized. Acoustic wake-up microsystems with absolutely zero power consumption in sleep mode can be realized in the architecture of zero-power recognition and zero-power sleep. Applications of acoustic wake-up microsystems are then elaborated, which are closely related to scientific research and our daily life. Finally, challenges and future research directions of acoustic wake-up microsystems are elaborated. With breakthroughs in software and hardware technologies, acoustic wake-up microsystems can be deployed for ultra-long-term and ultra-large-scale use in various fields, and play important roles in the Internet of Things.

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Low-Power Resonant Acceleration Switch for Unattended Sensor Wake-Up

Cited by 11 publications

References 16 publications

Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures

Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures

Micromechanical vibro-impact systems: a review

Acoustic Wake-Up Technology for Microsystems: A Review

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Low-Power Resonant Acceleration Switch for Unattended Sensor Wake-Up

Cited by 11 publications

References 16 publications

Approaching the Limits of Aspect Ratio in Free‐Standing Al2O33D Shell Structures

Approaching the Limits of Aspect Ratio in Free‐Standing Al2O33D Shell Structures

Micromechanical vibro-impact systems: a review

Acoustic Wake-Up Technology for Microsystems: A Review

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Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures

Approaching the Limits of Aspect Ratio in Free‐Standing Al₂O₃3D Shell Structures