Piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient

A technology of bulk acoustic wave resonator and piezoelectric film, which is applied in the direction of electrical components, impedance networks, etc., to achieve the effect of improving coupling coefficient and quality factor, enhancing reliability and heat dissipation performance, and suppressing stray mode effects

Pending Publication Date: 2020-09-22
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] With the popularization of 5G communication, massive data and real-time high-speed transmission have become the most important user requirements for future communication systems; according to Shannon's communication theory, the realization of high-spe

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  • Piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient
  • Piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient
  • Piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient

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Embodiment 1

[0042] This embodiment provides a piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient, the three-dimensional schematic diagram of its structure is as follows figure 1 As shown, top view as figure 2 As shown, the cross-section image 3 shown; including: a silicon-based substrate with insulating silicon dioxide, an interdigital transducer used to excite a transverse electric field, and a suspended free-vibrating piezoelectric thin-film resonator; specifically includes: sequentially stacked from bottom to top A silicon-based substrate 1, a bottom mass loading film 2, a piezoelectric film 3 and an interdigital transducer, wherein the interdigital transducer is formed in mirror-image symmetry of an input electrode 5 and an output electrode 6; the silicon-based substrate 1 Forming a cavity structure by etching;

[0043] The lengths of the electrode fingers of the input electrode 5 and the output electrode 6 are all equal; between the adja...

Embodiment 2

[0055] This embodiment provides a high-frequency high-coupling coefficient piezoelectric thin-film bulk acoustic resonator, the structural section of which is shown in Figure 14 shown, the rear view is as Figure 15 As shown, it also has a mass-loading structure, and its only difference from Example 1 is that the bottom mass-loading film 2 is etched to form a bottom-layer grid-like mass 9 that is vertically symmetrical to the top-layer grid-like mass 7 ; This structure has the highest symmetry, which can effectively reduce the scattered waves caused by structural asymmetry.

Embodiment 3

[0057] This embodiment provides a piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient, the top view of which is as follows Figure 16 As shown, it also has a mass loading structure. The only difference between it and Embodiment 1 is that the lengths of the electrode fingers that constitute the input electrode 5 and output electrode 6 of the interdigital transducer adopt a gradual change form, from the center to both sides. The same amplitude becomes shorter; at the same time, the upper and lower boundaries (i.e. short sides) of the top grid bar mass 7 remain flush with the suspended ends of the electrode fingers, so the length of the top grid bar mass 7 also adopts Gradient form that shortens equally from the center to both sides.

[0058] The structure in this embodiment is adopted to suppress the transverse mode of the resonator. The transverse mode is a very important type of stray mode in the acoustic wave device, which not only red...

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Abstract

The invention belongs to the technical field of radio frequency micro electro mechanical systems, and particularly provides a piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient, which is used for overcoming the defect of small coupling coefficient of the existing resonator unit. The sensor specifically comprises a silicon-based substrate, a bottom mass loading film, a piezoelectric film and an interdigital transducer, the bottom mass loading film, the piezoelectric film and the interdigital transducer are sequentially stacked on the silicon-based substrate, top grid-shaped mass blocks are arranged between adjacent electrode finger strips of the interdigital transducer, the long edges of the top grid-shaped mass blocks are parallel to the electrodefinger strips, and the short edges of the top grid-shaped mass blocks are flush with suspended ends of the electrode finger strips. According to the invention, the coupling coefficient and Q value ofthe resonator are effectively improved through the mass loading structure, stray loss is reduced, and the resonator is suitable for being made into a broadband filter; meanwhile, due to the adoption of a loading mass block structure, the heat dissipation performance of the resonance body is improved; in addition, the length of the top-layer mass block can be matched with that of the electrode finger strip, and the electrode finger strip adopts a length-gradient and pseudo-electrode-like structure, so that the transverse mode of the resonator is effectively suppressed.

Description

technical field [0001] The invention belongs to the technical field of radio frequency micro-electromechanical systems, and in particular relates to a piezoelectric film bulk acoustic wave resonator with high frequency and high coupling coefficient. Background technique [0002] With the popularization of 5G communication, massive data and real-time high-speed transmission have become the most important user requirements for future communication systems; according to Shannon's communication theory, the realization of high-speed communication networks must increase the channel bandwidth, so the broadband technology of the RF front-end has gradually become a limitation for base stations and The technical bottleneck in the development of communication hardware such as smart terminals. [0003] Bulk acoustic wave resonators use the principle of electro-acoustic-electric transduction, and the structure size is very small; through the series and parallel connection of acoustic fil...

Claims

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Application Information

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IPC IPC(8): H03H9/17
CPCH03H9/17Y02D30/70
Inventor 鲍景富吴兆辉梁起李亚伟
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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