Low loss, 3.7GHz wideband BAW filters, using high power single crystal AlN-on-SiC resonators

Shealy, J.B.; Vetury, R.; Gibb, Shawn R.; Hodge, Michael D.; Patel, Pinal; McLain, Michael A.; Feldman, Alexander Yu.; Boomgarden, Mark D.; Lewis, Michael P.; Hosse, Brook; Holden, R.L.

doi:10.1109/mwsym.2017.8058901

Cited by 26 publications

(9 citation statements)

References 8 publications

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“…Generally, (002) X-ray diffraction rocking curve FWHM of single crystal AlN can be 0.02–1°, compared with the typical FWHM of 2–3° in poly-crystalline AlN. Improved crystal quality in the single crystal AlN has been proved to result in improvements in acoustic velocity and potentially improved piezoelectric coefficients [ 36 ]. Moreover, single crystal AlN-based BAWs are superior to the poly-crystalline AlN devices.…”

Section: Methodsmentioning

confidence: 99%

“…In 2016, a group from Akoustis Technologies Inc. presented that single crystal AlN-based devices had more than double k eff 2 than poly-crystalline AlN-based devices in the upper bound case, and the FOM is typically 30% higher, although the Q-value is slightly lower in single crystal devices [ 41 ]. In 2017, the same group used metal-organic chemical vapor deposition (MOCVD) to obtain single crystal epitaxial AlN film with 0.5 [ 42 ] and 0.6 [ 36 ] um thickness 4H silicon carbide (SiC) substrates with 150 mm diameter. Resonators showed k eff 2 of 6.32% and 7.63%, and Q max of 1523 and 1572, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

et al. 2020

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With the rapid commercialization of fifth generation (5G) technology in the world, the market demand for radio frequency (RF) filters continues to grow. Acoustic wave technology has been attracting great attention as one of the effective solutions for achieving high-performance RF filter operations while offering low cost and small device size. Compared with surface acoustic wave (SAW) resonators, bulk acoustic wave (BAW) resonators have more potential in fabricating high- quality RF filters because of their lower insertion loss and better selectivity in the middle and high frequency bands above 2.5 GHz. Here, we provide a comprehensive review about BAW resonator researches, including materials, structure designs, and characteristics. The basic principles and details of recently proposed BAW resonators are carefully investigated. The materials of poly-crystalline aluminum nitride (AlN), single crystal AlN, doped AlN, and electrode are also analyzed and compared. Common approaches to enhance the performance of BAW resonators, suppression of spurious mode, low temperature sensitivity, and tuning ability are introduced with discussions and suggestions for further improvement. Finally, by looking into the challenges of high frequency, wide bandwidth, miniaturization, and high power level, we provide clues to specific materials, structure designs, and RF integration technologies for BAW resonators.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

et al. 2020

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“…Compared with polycrystalline AlN thin films that have been widely used in fabricating traditional BAW devices, single crystal AlN thin film has a higher electromechanical coupling coefficient and lower crystal defects, which would lead to larger filter bandwidth and lower insertion loss at high operation frequency. It is thus a promising material for the fabrication of high-performance BAW filters suitable for 5G communication [ 4 , 5 , 6 , 7 ]. With the development of GaN active circuits, 5G communication demands compatible processing between BAW filter and GaN HEMT circuits, so that they could be fabricated on single substrates as a monolithic microwave integrated circuit (MMIC) [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

The 3.4 GHz BAW RF Filter Based on Single Crystal AlN Resonator for 5G Application

et al. 2022

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To meet the stringent requirements of 5G communication, we proposed a high-performance bulk acoustic wave (BAW) filter based on single crystal AlN piezoelectric films on a SiC substrate. The fabrication of the BAW filter is compatible with the GaN high electron mobility transistor (HEMT) process, enabling the implementation of the integration of the BAW device and high-performance monolithic microwave integrated circuit (MMIC). The single crystal AlN piezoelectric film with 650-nm thickness was epitaxially grown on the SiC substrate by Metal Organic Chemical Vapor Deposition (MOCVD). After wafer bonding and substrate removal, the single crystal AlN film with electrode layers was transferred to another SiC wafer to form an air gap type BAW. Testing results showed that the fabricated resonators have a maximum Q-factor up to 837 at 3.3 GHz resonant frequency and electromechanical coupling coefficient up to 7.2%. Ladder-type filters were developed to verify the capabilities of the BAW and process, which has a center frequency of 3.38 GHz with 160 MHz 3 dB bandwidth. The filter achieved a minimum 1.5 dB insertion loss and more than 31 dB out-of-band rejection. The high performance of the filters is attributed to the high crystallinity and low defects of epitaxial single crystal AlN films.

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“…The bandwidth of the BAW filter is related to the electromechanical coupling coefficient ( K t 2 ) of piezoelectric material. AlN-based BAW filters are the most successful commercial application, typically having a relative bandwidth of 4.1% 9 because of poor K t 2 of AlN. Studies aimed at increasing acoustic filter bandwidth can be divided into two categories.…”

Section: Introductionmentioning

confidence: 99%

BAW Resonator with an Optimized SiO₂/Ta₂O₅ Reflector for 5G Applications

Shuai

Huang

et al. 2022

ACS Omega

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In the present work, a lithium niobate (LN) 43°Y cut LN film is transferred onto a substrate with 11 layers of SiO 2 /Ta 2 O 5 and solidly mounted resonators with a reflector are successfully fabricated with the multilayer structure. The design method and fabrication process are demonstrated. The finite element model and the Mason model are used. Scanning electron microscopy and atomic force microscopy are used to characterize film quality. An optimized design of a Bragg reflector to suppress the leakage of acoustic energy by thickness shear mode is proven to be effective. The influence of the reflector on parasitic modes and filter out-of-band suppression is analyzed. The resonator for 3.5 GHz shows an effective electromechanical coupling coefficient of 17.9%, and the figure of merit is 40.4, which is suitable for band pass filter on the N78 band with high rejection.

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Low loss, 3.7GHz wideband BAW filters, using high power single crystal AlN-on-SiC resonators

Cited by 26 publications

References 8 publications

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

The 3.4 GHz BAW RF Filter Based on Single Crystal AlN Resonator for 5G Application

BAW Resonator with an Optimized SiO₂/Ta₂O₅ Reflector for 5G Applications

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Low loss, 3.7GHz wideband BAW filters, using high power single crystal AlN-on-SiC resonators

Cited by 26 publications

References 8 publications

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

The 3.4 GHz BAW RF Filter Based on Single Crystal AlN Resonator for 5G Application

BAW Resonator with an Optimized SiO2/Ta2O5 Reflector for 5G Applications

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Product

Resources

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BAW Resonator with an Optimized SiO₂/Ta₂O₅ Reflector for 5G Applications