Impact Of High Sc Content On Crystal Morphology And RF Performance Of Sputtered Al<sub>1-x</sub>Sc<sub>x</sub>N SMR BAW

Bogner, Andreas; Timme, H.-J.; Bauder, Rudiger; Mutzbauer, Angelika; Pichler, Diana; Krenzer, Michael; Reccius, Christian H.; Weigel, Robert; Hagelauer, Amelie

doi:10.1109/ultsym.2019.8925777

Cited by 14 publications

(7 citation statements)

References 6 publications

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“…The thickness-shear type of Lamb modes excited by top interdigitated electrodes (IDTs) is studied in this work because of the large e 15 in Z-cut LiNbO 3 [42]. Nevertheless, the discussion in Section II can be readily applied to other orientations [59], other piezoelectric materials [33], [60], [61], or devices excited by the thickness electrical fields [27], [62].…”

Section: A Higher-order Lamb Modes In Piezoelectric Materialsmentioning

confidence: 99%

“…Third, scaling down devices (e.g., film thickness, electrode width) for attaining a higher center frequency and matching the system impedance might lead to worsened power handling and increased nonlinearity because more acoustic energy is concentrated in a smaller volume [18]- [20]. To address the challenges, novel acoustic platforms have been investigated in the past few years, including transferred thin films on costly substrates [21]- [25], new materials and acoustic modes with larger piezoelectric coefficients [26]- [33], and incorporated additional lumped electromagnetic (EM) elements [34]- [37].…”

Section: Introductionmentioning

confidence: 99%

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Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Yang

Link

et al. 2020

J. Microelectromech. Syst.

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In this work, we present a new paradigm for enabling gigahertz higher-order Lamb wave acoustic devices using complementarily oriented piezoelectric (COP) thin films. Acoustic characteristics are first theoretically explored with COP lithium niobate (LiNbO 3) thin films, showing their excellent frequency scalability, low loss, and high electromechanical coupling (k 2). Acoustic resonators and delay lines are then designed and implemented, targeting efficient excitation of higher-order Lamb waves with record-breaking low loss. The fabricated resonator shows a 2 nd-order symmetric (S2) resonance at 3.05 GHz with a high quality factor (Q) of 657, and a large k 2 of 21.5% and a 6 th-order symmetric (S6) resonance at 9.05 GHz with a high Q of 636 and a k 2 of 3.71%, both among the highest demonstrated for higher-order Lamb wave devices. The delay lines show an average insertion loss (IL) of 7.5 dB and the lowest reported propagation loss of 0.014 dB/µm at 4.4 GHz for S2. Notable acoustic passbands up to 15.1 GHz are identified. Upon further optimizations, the proposed COP platform can lead to gigahertz low-loss wideband acoustic components.

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Section: A Higher-order Lamb Modes In Piezoelectric Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Yang

Link

et al. 2020

J. Microelectromech. Syst.

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“…Research efforts have been devoted to investigate the inducements of the abnormal grains and the approaches to suppress the abnormal grains. Increasing Sc concentration has been confirmed to facilitate the growth of the abnormal grains [11][12][13]. Film stress is also identified to be another critical parameter for the amount of the abnormal grains and a compressive stress is believed to have a positive impact on the elimination of the grains [14,15].…”

Section: Introductionmentioning

confidence: 88%

Evaluation of the impact of abnormal grains on the performance of Sc_0.15Al_0.85N-based BAW resonators and filters

Liu

Chen

et al. 2022

J. Micromech. Microeng.

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ScxAl1-xN is a promising piezoelectric material for radio frequency communication applications with excellent electro-acoustic properties. However, the growth of abnormally oriented grains is widely observed in the Sc doped AlN films deposited by sputtering. In this work, for the first time, the impact of the abnormal grains in the Sc0.15Al0.85N films on the performance of bulk acoustic wave resonators and filters is systematically evaluated by both simulations and measurements. The correlation between the device performance and the abnormal grain parameters, including the density, dimension, crystal orientation, growth height, and the total volume of the abnormal grains, is evaluated and quantified. Simulation results show that the total volume of all abnormal grains in the whole device is the most critical factor among the parameters. Abnormal grains with randomly distributed parameters and around 6% total volume of the film can degrade the effective coupling coefficient of the resonator from 13.6% to 11%, leading to a 10.6% decrement of the filter bandwidth. Wafer-level device characterizations and measurements are performed, and the results are consistent with the simulations. This study provides a practical method for predicting the performance of the resonators and filters with abnormal grains, and a guideline for film quality evaluation.

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“…Recently, AlN thin film has got much attention because it has higher phase velocity (over 5000 m/s) compared to other piezoelectric thin films. [22][23][24][25][26][27][28][29] Moreover, it can be deposited on substrates with high phase velocity, such as diamond and SiC, resulting a great candidate for high frequency SAW devices. [30][31][32] The frequency of the device based on AlN/diamond structure reached 5 GHz [33], while a Sezawa wave filter based on ZnO/SiC structure with the center frequency of 6.8 GHz was prepared successfully in our previous work [34].…”

Section: Introductionmentioning

confidence: 99%

3D Layout of Interdigital Transducers for High Frequency Surface Acoustic Wave Devices

Shen

Luo

et al. 2020

IEEE Access

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The development of mobile communication sets higher demands on high frequency surface acoustic wave (SAW) devices. The layout of interdigital transducers (IDT) in SAW devices is in plane and the traditional methods of improving frequency for SAW devices are the increase of acoustic velocity and the reduction of wavelength. However, these methods have a limit due to the limited acoustic velocity and the photolithography limit. This work proposes a new way for the development of high frequency SAW devices by redesigning the layout of IDT in three dimensions (3D). The set of IDTs is split into two layers, i.e. the ground electrodes on one layer and the signal electrodes on the other layer. This 3D layout of IDTs dramatically narrows the horizontal gap between two adjacent electrodes, which can significantly increase the frequency. The frequency and the electromechanical coupling factor (K 2) of the four structures of SAW devices with the 3D layout of IDTs were studied by the finite element method (FEM). The results show that the frequency can be doubled under the same critical resolution of lithography due to the shortening of wavelength, and the 3D layout of IDTs is available for SAW devices based on piezoelectric thin film or piezoelectric single crystal. This work develops a new alternative to increase the working frequency of SAW devices.

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Impact Of High Sc Content On Crystal Morphology And RF Performance Of Sputtered Al_1-xSc_xN SMR BAW

Cited by 14 publications

References 6 publications

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Evaluation of the impact of abnormal grains on the performance of Sc_0.15Al_0.85N-based BAW resonators and filters

3D Layout of Interdigital Transducers for High Frequency Surface Acoustic Wave Devices

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Impact Of High Sc Content On Crystal Morphology And RF Performance Of Sputtered Al1-xScxN SMR BAW

Cited by 14 publications

References 6 publications

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Enabling Higher Order Lamb Wave Acoustic Devices With Complementarily Oriented Piezoelectric Thin Films

Evaluation of the impact of abnormal grains on the performance of Sc0.15Al0.85N-based BAW resonators and filters

3D Layout of Interdigital Transducers for High Frequency Surface Acoustic Wave Devices

Contact Info

Product

Resources

About

Impact Of High Sc Content On Crystal Morphology And RF Performance Of Sputtered Al_1-xSc_xN SMR BAW

Evaluation of the impact of abnormal grains on the performance of Sc_0.15Al_0.85N-based BAW resonators and filters