A 10MHz piezoresistive MEMS resonator with high Q (original) (raw)
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High-Q multi-frequency ring-shaped piezoelectric MEMS resonators
Microelectronics Journal, 2020
While MEMS resonators are emerging as a promising integrated clock-chip solution, often quality factor (Q) and spurious modes limit device performance. Moreover, realizing high-Q and multi-frequency simultaneously in a piezoelectric MEMS resonator is still comparatively difficult. In this research, a ring-shaped MEMS resonator outfitted with optimized electrodes was proposed to significantly suppress undesired resonant modes and then boosts the Q of rest resonant modes. To systematically explore the proposed design, numerical and experimental investigations were performed, revealing that the presence of optimized electrodes helps to counterpoise distributions of surface charge density and displacement current density in vertical direction, thereby results in the suppression of spurious modes. The maximum unloaded quality factor (Q u) of the fabricated ring-shaped resonators was up to 10,069 at 83.59 MHz. The measurement results of the resonator with optimized electrodes yielded three resonant modes with Q u large than 5,000, indicating that the high-Q and multi-frequency ringshaped resonator was satisfactorily achieved.
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Thin-film piezoelectric-on-silicon (TPoS) microelectromechanical (MEMS) resonators are required to have high Q-factor to offer satisfactory results in their application areas, such as oscillator, filter, and sensors. This paper proposed a phononic crystal (PnC)-reflector composite structure to improve the Q factor of TPoS resonators. A one-dimensional phononic crystal is designed and deployed on the tether aiming to suppress the acoustic leakage loss as the acoustic wave with frequency in the range of the PnC is not able to propagate through it, and a reflector is fixed on the anchoring boundaries to reflect the acoustic wave that lefts from the effect of the PnC. Several 10 MHz TPoS resonators are fabricated and tested from which the Q-factor of the proposed 10 MHz TPoS resonator which has PnC-reflector composite structure on the tether and anchoring boundaries achieved offers a loaded Q-factor of 4682 which is about a threefold improvement compared to that of the conventional reso...
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The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 mm × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage Vb between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of Vb, thus shifting its resonant frequency. The working principle has been first validated throug...
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Modeling and Simulation of Polysilicon Piezoresistors in a CMOS-MEMS Resonator for Mass Detection
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Sensors and Actuators A: Physical, 2019
Recently, piezoelectric resonators fabricated by using MEMS (i.e., micro-electro-mechanical systems) technology have received increasing attention in a large and diverse set of applications, including sensors, filters and timing references. One of the critical challenges for the actual application of MEMS resonators is further improving their quality factors (Qs) to respond the urgent demand of performance enhancement. Herein, a strategy by employing suspended frame structure and phononic crystals (PnC) was proposed to reduce the energy dissipation, and thus AlN-on-SOI MEMS resonators with high Q were successfully implemented. The suspended frame structure isolates the mechanical vibration between the resonant body and the anchoring substrate, while PnC arrays serve as a frequency-selective reflector to reduce the energy leakage. The multi-physics finite-element-analysis (FEA) and the experimental comparison were employed to systematically investigate the underlying mechanisms of the energy dissipation reduction of the proposed strategy. The unloaded Qs (i.e., Q u) of proposed resonators achieved maximum 7.8-fold and 1.5-fold improvements compared with that of bared resonators and that of those with only suspended frame structure, respectively.