Influence of Etching Trench on Keff2 of Film Bulk Acoustic Resonator

Gao, Chao; Zou, Yang; Zhou, Jie; Liu, Yan; Liu, Wenjuan; Cai, Yao; Sun, Chengliang

doi:10.3390/mi13010102

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…The capacitor capacitance value ( C p ) is related to the distance and area between the plates, which can be calculated by Equation (6):

where C 0 is the static capacitance extracted from the traditional FBAR MBVD model, S square is the area of a square, and S pentagon is the area of the pentagon. When the resonator is paralleled with a capacitor, through the MBVD model, f p can be expressed as [ 18 ]:

…”

Section: Device’s Structural Designmentioning

confidence: 99%

Aluminum Nitride-Based Adjustable Effective Electromechanical Coupling Coefficient Film Bulk Acoustic Resonator

Luo

Wen

et al. 2023

Micromachines

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The arrival of the 5G era has promoted the need for filters of different bandwidths. Thin-film bulk acoustic resonators have become the mainstream product for applications due to their excellent performance. The Keff2 of the FBAR greatly influences the bandwidth of the filter. In this paper, we designed an AlN-based adjustable Keff2 FBAR by designing parallel capacitors around the active area of the resonator. The parallel capacitance is introduced through the support column structure, which is compatible with conventional FBAR processes. The effects of different support column widths on Keff2 were verified by finite element simulation and experimental fabrication. The measured results show that the designed FBAR with support columns can achieve a Keff2 value that is 25.9% adjustable.

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“…The capacitor capacitance value ( C p ) is related to the distance and area between the plates, which can be calculated by Equation (6):

…”

Section: Device’s Structural Designmentioning

confidence: 99%

Aluminum Nitride-Based Adjustable Effective Electromechanical Coupling Coefficient Film Bulk Acoustic Resonator

Luo

Wen

et al. 2023

Micromachines

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“…The detailed fabrication process is demonstrated in Fig. surface for the deposition of the bottom Mo electrode and piezoelectric AlScN film 20 . In particular, an isolation wall instead of a swimming pool is used to reduce the difficulty of CMP due to the smaller polished area.…”

Section: Design and Fabricationmentioning

confidence: 99%

Aluminum scandium nitride thin-film bulk acoustic resonators for 5G wideband applications

et al. 2022

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Bulk acoustic wave (BAW) filters have been extensively used in consumer products for mobile communication systems due to their high performance and standard complementary metal-oxide-semiconductor (CMOS) compatible integration process. However, it is challenging for a traditional aluminum nitride (AlN)-based BAW filter to meet several allocated 5G bands with more than a 5% fractional bandwidth via an acoustic-only approach. In this work, we propose an Al0.8Sc0.2N-based film bulk acoustic wave resonator (FBAR) for the design of radio frequency (RF) filters. By taking advantage of a high-quality Al0.8Sc0.2N thin film, the fabricated resonators demonstrate a large Keff2 of 14.5% and an excellent figure of merit (FOM) up to 62. The temperature coefficient of frequency (TCF) of the proposed resonator is measured to be −19.2 ppm/°C, indicating excellent temperature stability. The fabricated filter has a center frequency of 4.24 GHz, a −3 dB bandwidth of 215 MHz, a small insertion loss (IL) of 1.881 dB, and a rejection >32 dB. This work paves the way for the realization of wideband acoustic filters operating in the 5G band.

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“…5) FBARs can be applied in high frequency, but can hardly achieve multifrequency on a single-chip. 6,7) The Lamb wave resonator (LWR) based on aluminum nitride (AlN) film compensates for the above shortcomings by utilizing interdigital electrodes (IDTs) on the surface of the high phase velocity (v a ) material, emerging as a research hotspot by virtue of its single-chip multi-band capability. [8][9][10] The LWR exhibits the characteristics of multi-mode and acoustic dispersion.…”

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confidence: 99%

Effective electromechanical coupling coefficient ( keff2 ) enhancement of a Lamb wave resonator with trapezoid grooves configuration

Fan

Zhou

et al. 2023

Appl. Phys. Express

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A first-order (S1 ) Lamb Wave Resonator (LWR) with trapezoid grooves configuration on the top surface of Aluminum Nitride (AlN) membrane between interdigital electrodes (IDTs) is proposed in this paper. Both the simulation and experiment results demonstrate that the K 2 eff can be enhanced with the depth of the trapezoid grooves increasing. Meanwhile, the spurious modes can be suppressed by the trapezoid grooves. 75% improvement on the K 2 eff has been achieved in a 2.45 GHz S1 mode LWR with trapezoid grooves with spurious modes free. The K 2 eff reaches up to 5.47% without quality factor degradation.

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Influence of Etching Trench on Keff2 of Film Bulk Acoustic Resonator

Cited by 6 publications

References 18 publications

Aluminum Nitride-Based Adjustable Effective Electromechanical Coupling Coefficient Film Bulk Acoustic Resonator

Aluminum Nitride-Based Adjustable Effective Electromechanical Coupling Coefficient Film Bulk Acoustic Resonator

Aluminum scandium nitride thin-film bulk acoustic resonators for 5G wideband applications

Effective electromechanical coupling coefficient ( keff2 ) enhancement of a Lamb wave resonator with trapezoid grooves configuration

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