Lowering motional resistance by partially HfO2 gap filling in double-ended tuning fork MEMS resonators

2017 ◽  
Author(s):  
Mariazel Maqueda Lopez ◽  
Emanuele A. Casu ◽  
Adrian M. Ionescu ◽  
Montserrat Fernandez-Bolanos
Keyword(s):  
Tuning Fork ◽  
Gap Filling ◽  
Mems Resonators ◽  
Motional Resistance

Dynamic behaviours of the Double-end tuning fork based comb-driven microelectromechanical resonators for modulating the magnetic flux synchronously

2021 ◽  
Author(s):  
Zhenxi Liu ◽  
Jiamin Chen ◽  
Wuhao Yang ◽  
Tianyi Zheng ◽  
Qifeng Jiao ◽  
...  
Keyword(s):  
Detection Limit ◽  
Magnetic Flux ◽  
Resonance Frequency ◽  
Tuning Fork ◽  
Paper Making ◽  
Initial Space ◽  
Mems Resonator ◽  
Mems Resonators ◽  
Mems Fabrication ◽  
First Time

Abstract MEMS resonators have been widely used in the magneto-resistive (MR) sensor for modulating the magnetic flux to enhance the detection limit. However, the manufacturing tolerances in MEMS fabrication processes make it challenging to fabricate the identical resonators with the same vibration frequency, which greatly decreases the detection limit of the MR sensor. To synchronize the MEMS resonators and improve the performance of the MR sensor, the double end tuning fork (DETF) based comb-driven MEMS resonators is proposed in this paper, making the system operate at the out-of-phase mode to complete the synchronization. The dynamic behaviour of the resonators is investigated through theoretical analysis, numerical solution based on MATLAB code and Simulink, and experimental verification. The results show that the transverse capacitances in the comb will significantly affect the resonance frequency due to the second-order electrostatic spring constant. It is the first time to observe the phenomenon that the resonant frequency increases with the increase of the bias, and it can also decrease with increasing the bias through adjusting the initial space between the fixed finger and the moving mass, they are different from the model about spring softening and spring hardening. Besides, the proposed DETF-based comb-driven resonators can suppress the in-phase and out-of-phase mode through adjusting the driving and sensing ports, and sensing method, meanwhile make the magnetic flux modulation fully synchronized, and maximize the modulation efficiency, and minimize the detection limit. These characteristics are appropriate for the MR sensor, even other devices that need to adjust the resonance frequency and vibration amplitude. Furthermore, the model and the design can also be extended to characteristic the single end tuning fork (SETF) based MEMS resonator and other MEMS-based MR sensors.

scholarly journals Analysis of Frequency Stability and Thermoelastic Effects for Slotted Tuning Fork MEMS Resonators

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2157 ◽  
Author(s):  
Valentina Zega ◽  
Attilio Frangi ◽  
Andrea Guercilena ◽  
Gabriele Gattere
Keyword(s):  
Tuning Fork ◽  
Frequency Stability ◽  
Mems Resonators ◽  
Thermoelastic Effects

Formation of Side Electrode on Quartz MEMS-Based Double-Ended Tuning Fork Using Enhanced Lift-Off Process

2011 ◽  
Vol 328-330 ◽  
pp. 507-510
Author(s):  
Jin Xing Liang ◽  
Xue Feng Li ◽  
Yun Fang Ni ◽  
Hong Sheng Li ◽  
Li Bin Huang ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Side Wall ◽  
Experimental Results ◽  
Surface Electrode ◽  
Pattern Design ◽  
Motional Resistance ◽  
Lift Off ◽  
Simple Surface

This paper presents an enhanced lift-off process for forming side electrode on the quartz –based double-ended tuning fork (DETF) resonator. In the case of fabricating quartz-based DETF, electrode pattern design is an important issue. Taking advantage of the piezoelectricity effect, a simple surface electrode can excite the flexural motion of the DETF, however it suffers from the large motional resistance. Proposed lift-off process can pattern excitation electrode on the side wall without using special photolithograph equipments. Experimental results demonstrated that the motional resistance can be reduced by several times by forming side electrode using proposed process.

Is L2 vocabulary learned better via context or via translation?

2018 ◽  
Vol 2 (1) ◽  
pp. 39-60
Author(s):  
Michael John Alroe ◽  
Heyo Reinders ◽  
Punchalee Wasanasomsithi
Keyword(s):  
Incidental Learning ◽  
Intentional Learning ◽  
Time On Task ◽  
Translation Group ◽  
Gap Filling ◽  
Freshmen Students ◽  
Context Group ◽  
Comprehensible Input ◽  
Post Test ◽  
L2 Vocabulary

Various studies have shown intentional learning of L2 vocabulary to be more efficient than incidental learning from exposure to comprehensible input. Some have argued that such learning may be further enhanced by recourse to L1 translation, particularly for weaker learners. The present study aims to determine if intentional learning of new vocabulary through L1 does indeed confer an advantage over intentional learning from an L2 context. To this end, 403 Thai freshmen students were pre-tested on thirty vocabulary items set for study on their English course. They were then randomly allocated to either a translation or context group to learn those items. Time on task was controlled. A delayed post-test showed that while the translation group was better at matching the thirty English words with Thai translations, albeit marginally so, there was no benefit conferred on the translation group when it came to using the words in a contextual gap-filling exercise. This finding held for both advanced and weaker learners.

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