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Film bulk acoustic resonator having multiple resonance modes and preparation method thereof and filter

A thin-film bulk acoustic wave and resonator technology, applied in electrical components, impedance networks, etc., can solve the problems of unfavorable RF front-end miniaturization, integrated development, increasing the complexity of the external impedance of the filter, and difficulty in debugging the whole machine. The whole machine is debugged, the difficulty of production is reduced, and the effect of integration is beneficial

Active Publication Date: 2016-08-24
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the case of using an FBAR filter, because the index of the FBAR filter is related to the impedance characteristics of the external circuit, the parallel connection of multiple filters increases the complexity of the external impedance of the filter, making the overall characteristics worse and making it difficult to debug the whole machine
In addition, multiple FBAR bandpass filters are required to achieve multiple frequency passband filtering functions, which is bound to be detrimental to the development of RF front-ends in the direction of miniaturization and integration

Method used

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  • Film bulk acoustic resonator having multiple resonance modes and preparation method thereof and filter
  • Film bulk acoustic resonator having multiple resonance modes and preparation method thereof and filter
  • Film bulk acoustic resonator having multiple resonance modes and preparation method thereof and filter

Examples

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Embodiment 1

[0039] The thin film bulk acoustic resonator of the multi-resonance mode of this embodiment is prepared by the following preparation method:

[0040] 1. Etch a groove on the surface of the silicon substrate 1 with a depth of 30 μm, and then deposit Si by PECVD 3 N 4 The substrate protection layer 2 has a thickness of 200nm to protect the silicon substrate. Such as figure 1 shown.

[0041] 2. In Si 3 N 4 A layer of PSG (phospho-quartz glass) is deposited on it by PECVD as a sacrificial layer.

[0042] 3. The surface of the sacrificial layer is polished by a CMP process.

[0043] 4. A layer of Mo bottom electrode 4 with a thickness of 200 nm is deposited on the polished surface by DC magnetron sputtering, and patterned by photolithography.

[0044] 5. Using radio frequency magnetron sputtering to deposit C-axis preferred orientation AlN piezoelectric film. And a multi-layer structure is etched by photolithography and ICP. This embodiment is a three-layer AlN piezoelectr...

Embodiment 2

[0050] 1. A layer of PSG (phosphorus quartz glass) is deposited by PECVD on the surface of the silicon substrate 1 as the sacrificial layer 7, and a pattern of the sacrificial layer is photoetched. Such as image 3 shown.

[0051] 2. Deposit a layer of Si by PECVD 3 N 4 The supporting layer 8 has a thickness of 300nm.

[0052] 3. A layer of Mo bottom electrode 4 with a thickness of 150 nm is patterned by photolithography and magnetron sputtering.

[0053] 4. Using radio frequency magnetron sputtering to deposit C-axis preferred orientation AlN piezoelectric film. And a multi-layer structure is etched by photolithography and ICP. This embodiment is a three-layer AlN piezoelectric film, and the area size of the AlN piezoelectric film decreases successively from bottom to top; the thickness of each layer is 2 μm, 0.8 μm, and 0.5 μm from bottom to top.

[0054] 5. A layer of Mo top electrode 6 with a thickness of 150 nm is patterned by photolithography and electron beam evap...

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Abstract

The invention discloses a film bulk acoustic resonator having multiple resonance modes. The film bulk acoustic resonator sequentially comprises a silicon substrate and piezoelectric stack structures; a cavity between the piezoelectric stack structures forms a resonant cavity of the film bulk acoustic resonator; and the piezoelectric stack structure comprises a bottom electrode, more than two layers of piezoelectric films and a top electrode in sequence from bottom to top. The film bulk acoustic resonator disclosed by the invention is provided with multiple resonance points; a multi-passband filter can be designed through multiple film bulk acoustic resonators in manners of cascading, bridging and the like; and thus, the number of FBAR filters on a wireless terminal can be greatly reduced.

Description

technical field [0001] The invention relates to a bulk acoustic wave resonator, in particular to a multi-resonance mode film bulk acoustic wave resonator, a preparation method thereof and a filter. Background technique [0002] Miniaturization, integration, and high performance are the requirements of wireless terminals for frequency devices. The solutions for traditional RF / microwave frequency devices are dielectric filters and surface acoustic wave filters. The former has better performance, but the size is too large. Although the latter is small in size, it has the disadvantages of low operating frequency, large insertion loss, and low power capacity. Film bulk acoustic resonator (FBAR) technology is currently the only RF filter technology that is expected to be integrated. It combines the superior performance of dielectric filters and the small size of surface acoustic wave (SAW) filters. At the same time Overcome the shortcomings of both. It has the advantages of hig...

Claims

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Application Information

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IPC IPC(8): H03H3/02H03H9/02H03H9/56H03H9/58
CPCH03H3/02H03H9/02007H03H9/02086H03H9/564H03H9/582H03H2003/023
Inventor 李国强刘国荣李洁
Owner SOUTH CHINA UNIV OF TECH
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