scholarly journals Observation of the fundamental Nyquist noise limit in an ultra-high Q-factor cryogenic bulk acoustic wave cavity

2014 ◽  
Vol 105 (15) ◽  
pp. 153505 ◽  
Author(s):  
Maxim Goryachev ◽  
Eugene N. Ivanov ◽  
Frank van Kann ◽  
Serge Galliou ◽  
Michael E. Tobar
Keyword(s):  
Acoustic Wave ◽  
Bulk Acoustic Wave ◽  
Q Factor ◽  
High Q ◽  
Noise Limit ◽  
Nyquist Noise

scholarly journals Enhanced tunable performance of high Q-factor BaxSr1−xTiO3 film bulk acoustic wave resonators

2013 ◽  
Vol 5 (3) ◽  
pp. 361-369 ◽  
Author(s):  
Andrei Vorobiev ◽  
Spartak Gevorgian
Keyword(s):  
Acoustic Wave ◽  
Resonance Frequency ◽  
Coupling Coefficient ◽  
Piezoelectric Effect ◽  
Bulk Acoustic Wave ◽  
Electromechanical Coupling Coefficient ◽  
Q Factor ◽  
High Q ◽  
Series Resonance ◽  
Film Bulk

Emerging intrinsically tunable film bulk acoustic wave(BAW) resonators allow the development of new generation reconfigurable and agile microwave circuits. In this paper, we demonstrate the enhancement of tunable performance of the high Q-factor BaxSr1−xTiO3 BAW – solidly mounted resonators (BAW–SMR) by varying Ba concentration. The Ba0.5Sr0.5TiO3 BAW–SMR reveal tunability of series resonance frequency up to 2.4%, electromechanical coupling coefficient up to 7.5% and rather high Q-factor, up to 250 at 5.3 GHz. Correlations between the measured electroacoustic parameters are analyzed using the theory of dc field-induced piezoelectric effect in paraelectric phase ferroelectrics. Higher coupling coefficient and tunability of resonance frequency of the Ba0.5Sr0.5TiO3 BAW–SMR are associated with higher tunability of permittivity. Strong anisotropy in field-induced piezoelectric effect is predicted with highest coupling coefficient in (001) direction of the BaxSr1−xTiO3 films. It is also shown that the tunability of series resonance frequency of Ba0.5Sr0.5TiO3 BAW–SMR is limited by relatively high and negative nonlinear electrostriction coefficient which is found to be m ≈ −4·1010 m/F. The BAW–SMR Q-factor is limited significantly by extrinsic acoustic loss associated with wave scattering at reflection from relatively rough top interface. The results of analysis show possible ways of further improvement of the performance of tunable BAW–SMR.

Q-Factor Improving of Film Bulk Acoustic Wave Resonator for Chip-Scale Atomic Clocks

2015 ◽  
Vol 645-646 ◽  
pp. 509-512 ◽  
Author(s):  
Zhong Shan Zhang ◽  
Liang Tang ◽  
Lei Ji
Keyword(s):  
Acoustic Wave ◽  
Resonant Frequency ◽  
Piezoelectric Layer ◽  
Bulk Acoustic Wave ◽  
Atomic Clocks ◽  
Q Factor ◽  
Silicon Oxide Layer ◽  
Electrode Layer ◽  
Composite Support ◽  
Film Bulk

Film bulk acoustic wave resonators (FBARs) with relatively high Q-factor are considered good candidates to be used in the RF module of chip-scale atomic clocks (CSACs). In order to simulate and analyze the resonant properties, the Mason equivalent circuit of the FBAR device is introduced, which consists of five parts including top electrode layer, low temperature silicon oxide layer, piezoelectric layer, bottom electrode layer and a composite support structure layer. With the practical processing conditions considered, the piezoelectric layer with a reasonable thickness of 1.30um is selected to achieve a FBAR device with resonant frequency 4.60GHz and Q-factor 278 by the simulation and analysis. In order to further improve the Q-factor, SiO2 thin films with thicknesses from 0.10um to 0.50um placed between the top electrode and piezoelectric layer are introduced. However, as the SiO2 thin film is introduced, the resonant frequency of the FBAR device will drop. In order to keep the resonant frequency fixed to 4.60GHz, the thickness of the piezoelectric layer is adjusted. Finally, the FBAR device resonating at 4.60GHz with Q-factor 627 is achieved, the thicknesses of the SiO2 film and piezoelectric layer of which are 0.20um and 0.69um respectively. The Q-factor of the FBAR device improves about 350, and the FBAR device is expected to be used in CSACs.

scholarly journals Q-Factor Enhancement of Thin-Film Piezoelectric-on-Silicon MEMS Resonator by Phononic Crystal-Reflector Composite Structure

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1130
Author(s):  
Jiacheng Liu ◽  
Temesgen Bailie Workie ◽  
Ting Wu ◽  
Zhaohui Wu ◽  
Keyuan Gong ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Composite Structure ◽  
Phononic Crystal ◽  
Q Factor ◽  
Leakage Loss ◽  
One Dimensional ◽  
High Q ◽  
Mems Resonator ◽  
Mems Resonators

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 resonator which is about 1570.

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