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Novel FBAR filter and preparation method thereof

A filter, a new type of technology, applied to electrical components, impedance networks, etc., to reduce energy loss, reduce stress, and suppress clutter

Pending Publication Date: 2021-04-16
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With this preparation method, no sacrificial layer is used during the preparation process, which reduces the damage to the piezoelectric film, thereby overcoming the problem of adverse effects on the filter structure during the removal of the sacrificial layer, and this method is used in the preparation of the lining The method of etching the groove on the bottom and preparing the piezoelectric film in the groove can effectively reduce the stress of the piezoelectric film, suppress clutter, and reduce energy loss, which can improve the quality of the piezoelectric film and reduce the thickness of the bulk acoustic resonator. Insertion loss, improve Q value and electromechanical coupling coefficient, will become a solution for RF filters in high frequency and high power applications in the future

Method used

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  • Novel FBAR filter and preparation method thereof
  • Novel FBAR filter and preparation method thereof
  • Novel FBAR filter and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0038] A new type of FBAR filter, which is formed by cascading n resonators, n is a positive integer and n≥1; as Figure 9 As shown, the resonator includes a support substrate 106, an air cavity support layer 105, a bottom electrode 104, a seed layer 103, a piezoelectric thin film structure layer 102, a top electrode 107, and a bottom electrode lead 108; the air cavity support layer There are two 105, respectively laminated on the support substrate 106, the bottom electrode 104 is respectively connected to the two air cavity support layers 105, the bottom electrode 104, the air cavity support layer 105 and the support substrate 106 form a cavity; The seed layer is stacked on the bottom electrode 104 and the air cavity support layer 105 ; the piezoelectric film structure layer 102 and the top electrode 107 are stacked on the seed layer 103 in sequence; the bottom electrode lead 108 is connected to the bottom electrode 104 .

[0039] The supporting substrate 106 is a silicon sub...

Embodiment 2

[0048] A preparation method of a novel FBAR filter, the specific preparation method is as follows:

[0049] (1) if figure 2 As shown, take a preparation substrate 110, the preparation substrate 110 can be a substrate material of silicon, silicon carbide, sapphire, glass, metal or organic polymer;

[0050] (2) if image 3 As shown, the groove 101 is etched on the prepared substrate 110 by an etching method;

[0051] (3) if Figure 4 As shown, the piezoelectric thin film structure layer 102 is prepared by chemical vapor deposition or sputtering in the groove 101. The piezoelectric thin film structure layer 102 is a single crystal or polycrystalline aluminum nitride material, and can also be ZnO, PZT, etc. Materials with electrical properties, the thickness of the piezoelectric film structure layer 102 is between 0.02 and 10 microns.

[0052] (4) if Figure 5 As shown, the seed layer 103 and the bottom electrode 104 are prepared by chemical vapor deposition or sputtering or...

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Abstract

The invention discloses a novel FBAR filter and a preparation method thereof. The method comprises the steps of etching a groove in a preparation substrate, preparing a piezoelectric material and a bottom electrode in the groove, preparing a thin seed layer, preparing an air cavity supporting layer and taking a supporting substrate before the bottom electrode is prepared, bonding the supporting substrate with the preparation substrate and the air cavity supporting layer, removing the preparation substrate, exposing the piezoelectric material; preparing a top electrode on the piezoelectric material, and leading out a bottom electrode to obtain the filter formed by cascading a plurality of resonators. According to the invention, through a method of digging the groove in the preparation substrate and then growing the piezoelectric material, the problem of cracks caused by excessive stress due to growth of the whole piezoelectric film is effectively avoided, the stress of the piezoelectric film is reduced, and meanwhile, the problem of energy loss caused by transverse transmission of energy is effectively avoided due to discontinuity of the piezoelectric film of each resonance unit. And meanwhile, clutters can be effectively suppressed, and the preparation yield and performance of the filter are improved.

Description

technical field [0001] The invention belongs to the technical field of radio frequency filtering, and in particular relates to a novel FBAR filter and a preparation method thereof. Background technique [0002] The multi-functional development of wireless communication terminals has put forward high technical requirements for radio frequency devices such as miniaturization, high frequency, high performance, low power consumption, and low cost. The traditional surface acoustic wave filter (SAW) has a large insertion loss in the high frequency band above 2.4GHz, and the dielectric filter has good performance but is too large. Film Bulk Acoustic Resonator (FBAR) technology is a new radio frequency device technology that has emerged in recent years with the improvement of processing technology and the rapid development of modern wireless communication technology, especially personal wireless communication technology. It has a very high quality factor Q value (above 1000) and ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H9/17H03H9/54
CPCH03H9/17H03H9/54
Inventor 李国强衣新燕赵利帅欧阳佩东刘红斌张铁林
Owner SOUTH CHINA UNIV OF TECH