Fabrication and testing of hemispherical MEMS wineglass resonators

Pai, Pradeep; Chowdhury, Faisal K.; Pourzand, Hoorad; Tabib-Azar, Massood

doi:10.1109/memsys.2013.6474333

Cited by 18 publications

(9 citation statements)

References 8 publications

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“…Their use for applications is not a recent trend and a renewed interest has accelerated in the recent years with the motivation to replace conventional polluting and cumbersome embedded batteries and to facilitate the development of fully autonomous EEH particularly for wireless applications . Oxides such as silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), combined SiO 2 /Si 3 N 4 , or aluminum oxide (Al 2 O 3 ) have proven to be interesting electrets for integration in microelectromechanical systems (MEMS) . However, these oxides cannot be chosen if it is desired to develop flexible or large‐scale transducers that exceed the conventional dimensions found in MEMS and also for low‐cost transducers.…”

Section: Introductionmentioning

confidence: 99%

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

Lagomarsini

Jean‐Mistral

Kachroudi

et al. 2019

J of Applied Polymer Sci

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Parylene C is used in many applications due to its high properties but it remains a material with moderate performance as long as it is intended for use as an electret. Hence, the generally accepted idea, rightly so, in the scientific and industrial community not to necessarily select parylene (i.e., parylene C) for applications where the endurance of the electret is a strong criterion. Our study provided a new perspective on the performance of parylenes as electret. In this case, we will talk about fluorinated Parylenes of the VT‐4 type and especially AF‐4 variant. Their thermal stability is outstanding and a charge stability is almost total up to 100 °C. A 50% reduction in the charge is recorded at a temperature as high as of 220 °C (9 μm thick Parylene AF‐4), making it one of the most efficient polymer electrets to date. Negatively and positively charged Parylene AF‐4 electrets presented similar performance over long durations, which is out of ordinary for the commonly employed polymeric electrets. Finally, these fluorinated polymers are therefore particularly promising new candidates for applications in electret‐based converters for energy harvesting. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48790.

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Section: Introductionmentioning

confidence: 99%

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

Lagomarsini

Jean‐Mistral

Kachroudi

et al. 2019

J of Applied Polymer Sci

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“…As the vital component of MSVG, micro-shell resonators (MSRs) of excellent performance require a high Q-factor and matched modal frequencies between the working modes. At present, there are two different strategies to fabricate MSRs: (1) Deposition or sputtering of the resonator material (such as polysilicon, polycrystalline diamond and SiO 2 ) into a spherical cavity [3,4,5,6] and (2) the plastic deformation of a device layer (such as Pyrex, metallic glass, and fused silica) using a micro glassblowing process [7,8,9]. Among these different MSRs, fused silica (FS) MSRs fabricated by micro glass-blowing show the highest Q-factor, thanks to the excellent material properties of FS, the ultra-smooth surface, and small intrinsic loss.…”

Section: Introductionmentioning

confidence: 99%

“…As micro-machine technology has advanced, Senkal et al have successfully fabricated MSRs with a frequency split as low as 0.1 Hz [21]. However, according to the published papers, frequency splits of most FS MSRs are still in the order of 10 Hz [3,4,5,6,7,8,9]. This is because the stability drift of MSVG is a direct function of frequency split, and post frequency tuning methods are necessary for gyroscopic application.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Trimming Effects on the Quality Factor of Micro-Shell Resonators Vibrating in Wineglass Modes

Lü

Xiao

et al. 2019

Micromachines

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Frequency trimming based on mass and stiffness modification is an important post-fabrication process for micro-shell resonators (MSRs). However, the trimming effects on the quality factor are seldom studied, although they may have great influence on the performance of the resonator. This paper presents a study on the quality factor (Q-factor) variation of trimmed micro-shell resonators (MSR). Thermoelastic damping (QTED) and anchor loss (Qanchor) are found to be the dominant energy loss mechanisms resulting in the reduction of the overall Q-factor, according to finite element method (FEM). The effects of different trimming methods on QTED and Qanchor are studied here, respectively. It is found that trimming grooves ablated in the rim of the resonator can cause a ~1–10% reduction of QTED, and the length of trimming groove is positively related to the reduction of QTED. The reduction of QTED caused by the mass adding process is mainly related to the thermal expansion coefficient and density of the additive and contact area between the resonator and additive masses. Besides, the first and second harmonic errors caused by asymmetrical trimming can cause a 10–90% reduction of Qanchor. Finally, trimming experiments were conducted on different resonators and the results were compared with FEM simulation. The work presented in this paper could help to optimize the trimming process of MSRs.

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“…Using a MEMS-based process, many different mHRGs and uHRGs have already been studied by global research teams. The different structural designs of the resonator mainly include hollow hemisphere [ 2 ], wineglass [ 3 ], disk [ 4 ], these resonators are usually surrounded by several coupled drive and sense electrodes. The fabrication processes of the resonator also differ, including deep reactive ion etching (DRIE), glassblowing [ 5 ], atomic layer deposition [ 6 ], sacrificial layer etching [ 7 ], or a combination of the above methods.…”

Section: Introductionmentioning

confidence: 99%

The Application of Chemical Foaming Method in the Fabrication of Micro Glass Hemisphere Resonator

et al. 2018

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Many researchers have studied the miniaturization of the hemisphere resonator gyroscope for decades. The hemisphere resonator (HSR), as the core component, has a size that has been reduced to the submillimeter level. We developed a method of batch production of micro-hemisphere shell resonators based on a glass-blowing process to obtain larger hemisphere shells with a higher ratio of height to diameter (H/D), we introduced the chemical foaming process (CFP) and acquired an optimized hemisphere shell; the contrasted and improved H/D of the hemisphere shell are 0.61 and 0.80, respectively. Finally, we increased the volume of glass shell resonator by 51.48 times while decreasing the four-node wineglass resonant frequencies from 7.24 MHz to 0.98 MHz. The larger HSR with greater surface area is helpful for setting larger surrounding drive and sense capacitive electrodes, thereby enhancing the sensitivity of HSR to the rotation. This CFP method not only provides more convenience to control the shape of a hemisphere shell but also reduces non-negligible cost in the fabrication process. In addition, this method may inspire some other research fields, e.g., microfluidics, chemical analysis, and wafer level package (WLP).

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Fabrication and testing of hemispherical MEMS wineglass resonators

Cited by 18 publications

References 8 publications

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

Outstanding performance of parylene polymers as electrets for energy harvesting and high‐temperature applications

A Study on the Trimming Effects on the Quality Factor of Micro-Shell Resonators Vibrating in Wineglass Modes

The Application of Chemical Foaming Method in the Fabrication of Micro Glass Hemisphere Resonator

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