阅读说明：本技术 有效机电耦合系数可调的超高频谐振器 (Ultra-high frequency resonator with adjustable effective electromechanical coupling coefficient ) 是由 孙成亮 温志伟 刘文娟 蔡耀 刘婕妤 徐沁文 谷曦宇 曲远航 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种有效机电耦合系数可调的超高频谐振器,其结构包括：沟槽,电极,压电薄膜；电极位于压电薄膜上表面。沟槽横截面为矩形、梯形、弧形中任一种,长度方向与电极长度方向一致,沟槽数目、宽度和深度据实际情况确定。沟槽可位于压电薄膜上表面或下表面或位于上下表面,若其位于压电薄膜上表面,则位于电极左右两侧；若其位于压电薄膜下表面,则位于电极正下方；若其位于压电薄膜上下表面,则上表面的沟槽位于电极左右两侧,下表面的沟槽位于电极正下方。刻蚀沟槽能够有效减小超高频谐振器的带宽,且可以通过改变沟槽的宽度和深度调节有效机电耦合系数,实现带宽可调。(The invention discloses an ultrahigh frequency resonator with adjustable effective electromechanical coupling coefficient, which structurally comprises: a trench, an electrode, a piezoelectric film; the electrode is located on the upper surface of the piezoelectric film. The cross section of the groove is any one of rectangle, trapezoid and arc, the length direction is consistent with the length direction of the electrode, and the number, the width and the depth of the groove are determined according to actual conditions. The grooves can be positioned on the upper surface or the lower surface of the piezoelectric film or on the upper surface and the lower surface of the piezoelectric film, and if the grooves are positioned on the upper surface of the piezoelectric film, the grooves are positioned on the left side and the right side of the electrode; if the piezoelectric film is positioned on the lower surface of the piezoelectric film, the piezoelectric film is positioned right below the electrode; if the piezoelectric film is positioned on the upper surface and the lower surface of the piezoelectric film, the grooves on the upper surface are positioned on the left side and the right side of the electrode, and the grooves on the lower surface are positioned under the electrode. The bandwidth of the ultrahigh frequency resonator can be effectively reduced by etching the groove, and the effective electromechanical coupling coefficient can be adjusted by changing the width and the depth of the groove, so that the adjustable bandwidth is realized.)

1. An ultra-high frequency resonator with adjustable electromechanical coupling coefficient is characterized in that: comprises a groove, an electrode and a piezoelectric film;

the cross section of the groove is any one of rectangle, trapezoid and arc, and the length direction of the groove is consistent with that of the electrode; the number, width and depth of the grooves can be determined according to the number of the piezoelectric films and the electrodes; the groove is positioned on the upper surface or the lower surface of the piezoelectric film, or positioned on the upper surface and the lower surface of the piezoelectric film simultaneously:

if the grooves are positioned on the upper surface of the piezoelectric film, the grooves are positioned on the left side and the right side of the electrode;

if the groove is positioned on the lower surface of the piezoelectric film, the groove is positioned right below the electrode;

if the grooves are positioned on the upper surface and the lower surface of the piezoelectric film at the same time, the grooves on the upper surface of the piezoelectric film are positioned on the left side and the right side of the electrode, and the grooves on the lower surface of the piezoelectric film are positioned under the electrode.

2. The tunable electromechanical coupling coefficient vhf resonator of claim 1, wherein:

the electrodes are single interdigital electrodes or double interdigital electrodes and are positioned on the upper surface of the piezoelectric film;

the electrode material is any one of Mo, Al, Cu, Au, Ti, Cr and W or a composite material taking several of the Mo, Al, Cu, Au, Ti, Cr and W as components; the shape of the electrode is any one of quadrangle, pentagon, ring or ellipse;

the groove canBy air, SiO₂、AlN、ScAlN、SiC、ZnO、PVDF、PZT、LiTaO₃Any one or more of them as the component of the composite material.

3. The tunable electromechanical coupling coefficient vhf resonator of claim 1 or 2, wherein:

the piezoelectric film material is AlN, ZnO or LiNbO₃、LiTaO₃Any one of PZT and PVDF or a composite material taking a plurality of PZT and PVDF as components;

the shape of the piezoelectric film is any one of quadrangle, pentagon, hexagon, circle, ellipse or ring; and the piezoelectric film is X-cut, Y-cut or Z-cut, or material orientation obtained by rotating different Euler angles.

Technical Field

The invention belongs to the technical field of radio frequency resonators, and particularly relates to an ultrahigh frequency resonator with an adjustable effective electromechanical coupling coefficient.

Background

With the advent of the age of 5G, the number of frequency bands continues to increase. In the face of increasingly crowded frequency bands, the market demands for high-frequency and ultrahigh-frequency filter frequency bands are increasingly greater, and the demands for multi-band high-frequency filters are sharply increased. This puts higher demands on the performance of the piezoelectric resonator. The surface acoustic wave resonator is widely applied to a radio frequency front end in the early days, but is mainly applied to a low-frequency market due to low phase speed, limitation of photoetching and the like, and excellent performance is difficult to maintain in a high-frequency band. Compared with the surface acoustic wave, the Film Bulk Acoustic Resonator (FBAR) has lower insertion loss and better selectivity in a middle and high frequency band above 2.5GHz, has higher mechanical quality factor Q, can enable a skirt edge to be steeper, and can be applied to the high-frequency filter market instead of the surface acoustic wave resonator.

However, SAW and FBAR have limited applications in the ultra-high frequency field, and in recent years, a new resonator has appeared in the ultra-high frequency field, but the bandwidth (Δ f ═ f) of the new resonator is high_p–f_s) Often more than 1GHz, it is difficult to use the resonator to realize a filter frequency band less than 1GHz, such as n79(4.4GHz-5GHz), and if the uhf resonator is to realize a certain smaller frequency band, the bandwidth problem of the uhf resonator needs to be solved urgently. The invention aims at the ultrahigh frequency resonator, realizes the requirement of reducing the bandwidth of the ultrahigh frequency resonator, and has effective electromechanical coupling coefficientCorrelation positively correlated with bandwidthAnd therefore its bandwidth, i.e. the effective electromechanical coupling coefficient, is reduced.

Disclosure of Invention

In order to reduce the effective electromechanical coupling coefficient of the ultrahigh frequency resonator, the invention provides the ultrahigh frequency resonator with the adjustable electromechanical coupling coefficient.

In order to achieve the above object, the present invention provides an ultra-high frequency resonator with adjustable electromechanical coupling coefficient, which is characterized in that: comprises a groove, an electrode and a piezoelectric film;

the cross section of the groove is any one of rectangle, trapezoid and arc, and the length direction of the groove is consistent with that of the electrode; the number, width and depth of the grooves can be determined according to the number of the piezoelectric films and the electrodes; the groove is positioned on the upper surface or the lower surface of the piezoelectric film, or positioned on the upper surface and the lower surface of the piezoelectric film simultaneously:

if the grooves are positioned on the upper surface of the piezoelectric film, the grooves are positioned on the left side and the right side of the electrode;

if the groove is positioned on the lower surface of the piezoelectric film, the groove is positioned right below the electrode;

if the grooves are positioned on the upper surface and the lower surface of the piezoelectric film at the same time, the grooves on the upper surface of the piezoelectric film are positioned on the left side and the right side of the electrode, and the grooves on the lower surface of the piezoelectric film are positioned under the electrode.

Preferably, the electrode is a single interdigital electrode or a double interdigital electrode and is positioned on the upper surface of the piezoelectric film;

the electrode material is any one of Mo, Al, Cu, Au, Ti, Cr and W or a composite material taking several of the Mo, Al, Cu, Au, Ti, Cr and W as components; the shape of the electrode is any one of quadrangle, pentagon, ring or ellipse;

the groove can be made of SiO₂AlN, ScAlN, SiC, ZnO, PVDF, PZT or LiTaO₃Any one or more of the above materials as a component;

further, the piezoelectric thin film material is AlN, ZnO or LiNbO₃、LiTaO₃Any one of PZT and PVDF or a composite material taking a plurality of PZT and PVDF as components;

the shape of the piezoelectric film is any one of quadrangle, pentagon, hexagon, circle, ellipse or ring; and the piezoelectric film is X-cut, Y-cut or Z-cut, or material orientation obtained by rotating different Euler angles.

Specifically, the structure of the uhf resonator with adjustable effective electromechanical coupling coefficient in the most preferred embodiment includes: a trench, an electrode, a piezoelectric film; the electrode is a single interdigital electrode or a double interdigital electrode, is positioned on the upper surface of the piezoelectric film, is made of any one or a composite material taking a plurality of Mo, Al, Cu, Au, Ti, Cr and W as components, and is in a polygonal or irregular shape such as a rectangle, a trapezoid and the like. The cross section of the groove is in a polygon shape such as a rectangle, a trapezoid and the like, the length direction of the groove is consistent with that of the electrode, and the number, the width and the depth of the groove can be determined according to the number of the piezoelectric films and the number of the electrodes. The grooves can be positioned on the upper surface or the lower surface of the piezoelectric film, and also can be positioned on the upper surface and the lower surface of the piezoelectric film at the same time, if the grooves are positioned on the upper surface of the piezoelectric film, the grooves are positioned on the left side and the right side of the electrode; if the groove is positioned on the lower surface of the piezoelectric film, the groove is positioned right below the electrode; if the grooves are simultaneously positioned on the upper surface and the lower surface of the piezoelectric film, the grooves on the upper surface of the piezoelectric film are positioned on the left side and the right side of the electrode, the grooves on the lower surface of the piezoelectric film are positioned under the electrode, and the grooves can be made of SiO₂、AlN、ScAlN、SiC、ZnO、PVDF、PZT、LiTaO₃Any one or a plurality of composite materials which are taken as components are filled and filled. The piezoelectric film material is AlN, ZnO or LiNbO₃、LiTaO₃The piezoelectric film is a material oriented by X-cutting, Y-cutting or Z-cutting, or rotating at different Euler angles.

In the ultrahigh frequency resonator with the adjustable effective electromechanical coupling coefficient, the effective electromechanical coupling coefficient is changed by changing the width and the depth of the etched groove, so that the bandwidth of the ultrahigh frequency resonator can be effectively reduced, and the adjustable bandwidth is realized.

The invention has the following beneficial effects and advantages:

the ultrahigh frequency resonator of the invention can obviously reduce the effective electromechanical coupling coefficient by only etching the groove on the upper surface or the lower surface of the piezoelectric film or simultaneously etching the groove on the upper surface and the lower surface, namely reducing the bandwidth of the ultrahigh frequency resonator, and can realize the adjustable bandwidth of the ultrahigh frequency resonator by changing the width and the depth of the groove.

Description of the drawings:

FIG. 1 is a schematic structural view of an effective electromechanical coupling coefficient adjustable UHF resonator of the present invention;

fig. 2 is a top view of the uhf resonator of the present invention with adjustable effective electromechanical coupling factor;

fig. 3 is a cross-sectional view of a uhf resonator with adjustable effective electromechanical coupling factor according to the present invention;

fig. 4 is a graph comparing the simulation effects of the uhf resonator in example 1 of the present invention;

fig. 5 is a graph of the effective electromechanical coupling coefficient of the uhf resonator in example 1 of the present invention as a function of the trench depth;

fig. 6 is a graph of the effective electromechanical coupling coefficient of the uhf resonator in embodiment 1 of the present invention as a function of the trench width;

fig. 7 is a schematic structural view of an uhf resonator in embodiment 2 of the present invention;

fig. 8 is a top view of the uhf resonator in embodiment 2 of the present invention;

fig. 9 is a sectional view of a uhf resonator in embodiment 2 of the present invention;

fig. 10 is a schematic view of the structure of the uhf resonator in embodiment 3 of the present invention;

fig. 11 is a top view of the uhf resonator in embodiment 3 of the present invention;

fig. 12 is a sectional view of the uhf resonator in embodiment 3 of the invention;

fig. 13 is a schematic view of the structure of the uhf resonator in embodiment 4 of the present invention;

fig. 14 is a top view of the uhf resonator in embodiment 4 of the present invention;

fig. 15 is a sectional view of the uhf resonator in embodiment 4 of the present invention;

fig. 16 is a schematic view of the structure of the uhf resonator in embodiment 5 of the present invention;

fig. 17 is a top view of the uhf resonator in embodiment 5 of the present invention;

fig. 18 is a sectional view of the uhf resonator in embodiment 5 of the invention;

fig. 19 is a schematic view of the structure of the uhf resonator in embodiment 6 of the present invention;

fig. 20 is a top view of the uhf resonator in embodiment 6 of the present invention;

fig. 21 is a sectional view of the uhf resonator in embodiment 6 of the invention;

in the figure: 1. piezoelectric film, 2, grooves, 3, interdigital electrodes.

Detailed Description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The ultrahigh frequency resonator adopts a method of etching grooves on two sides of the interdigital electrode of the piezoelectric film or the lower surface of the piezoelectric film or on the upper surface and the lower surface of the piezoelectric film simultaneously, so that the transverse propagation wavelength of the resonator can be reduced, and the series resonance frequency f is improved_sBut a parallel resonant frequency f_pWithout change, the effective electromechanical coupling coefficient can be effectively reduced finally, and the effective electromechanical coupling coefficient can be adjusted by controlling the width and the depth of the groove.

The structure of the ultrahigh frequency resonator with adjustable effective electromechanical coupling coefficient comprises: a trench, an electrode, a piezoelectric film;

in a specific implementation mode, the electrode is a single-interdigital electrode or a double-interdigital electrode, is located on the upper surface of the piezoelectric film, is filled with any one of Mo, Al, Cu, Au, Ti, Cr and W or a composite material taking a plurality of the Mo, Al, Cu, Au, Ti, Cr and W as components, and is in a polygonal shape or an arc shape such as a rectangle, a trapezoid and the like. The electrode may preferably be a Mo metal material.

In a specific embodiment, the cross section of the groove is any one of rectangular, trapezoidal and arcThe length direction is consistent with the electrodes, and the number of the grooves, the width and the depth can be determined according to the number of the piezoelectric films and the electrodes. The grooves can be positioned on the upper surface or the lower surface of the piezoelectric film, and also can be positioned on the upper surface and the lower surface of the piezoelectric film at the same time, if the grooves are positioned on the upper surface of the piezoelectric film, the grooves are positioned on the left side and the right side of the electrode; if the groove is positioned on the lower surface of the piezoelectric film, the groove is positioned right below the electrode; if the grooves are simultaneously positioned on the upper surface and the lower surface of the piezoelectric film, the grooves on the upper surface of the piezoelectric film are positioned on the left side and the right side of the electrode, the grooves on the lower surface of the piezoelectric film are positioned under the electrode, and the grooves can be made of SiO₂、AlN、ScAlN、SiC、ZnO、PVDF、PZT、LiTaO₃Any one or more of them as the component of the composite material.

In a specific embodiment, the piezoelectric thin film material is AlN, ZnO, LiNbO₃、LiTaO₃The piezoelectric film is made of any one of the PZT and the PVDF or a composite material taking a plurality of the PZT and the PVDF as components, the shape of the composite material is any one of quadrangle, pentagon, hexagon, circle, ellipse or ring, and the piezoelectric film is in a material orientation obtained by X cutting, Y cutting or Z cutting or rotating different Euler angles.

Example 1

As shown in fig. 1-3, the schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 1 are shown:

in embodiment 1, the ultra-high frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, and etching grooves 2 are located on two sides of the interdigital electrode on the piezoelectric upper surface.

As shown in fig. 4-6:

in the simulation effect diagram of the ultra-high frequency resonator with the adjustable effective electromechanical coupling coefficient in this embodiment 1, it can be known that the effective electromechanical coupling coefficient of the ultra-high frequency resonator with the etched trench is obviously reduced.

In the graph of the relationship between the effective electromechanical coupling coefficient and the trench depth of the uhf resonator in this embodiment 1, it can be seen that the effective electromechanical coupling coefficient decreases as the trench depth increases.

As can be seen from the graph of the relationship between the effective electromechanical coupling coefficient and the trench width of the uhf resonator in this embodiment 1, the effective electromechanical coupling coefficient decreases as the trench width increases.

Example 2

Fig. 7-9 are schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 2:

in embodiment 2, the ultrahigh frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, and the etching groove 2 is located right below the interdigital electrode on the lower surface of the piezoelectric film.

Example 3

As shown in fig. 10-12, the schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 3 are shown:

in embodiment 3, the ultra-high frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, an etched groove 2 is simultaneously located on the upper and lower surfaces of the piezoelectric film, the groove on the upper surface of the piezoelectric film is located on the left and right sides of the interdigital electrode or under the electrode, and the groove on the lower surface of the piezoelectric film is located under the interdigital electrode.

Example 4

Fig. 13-15 are schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 4:

in embodiment 4, the ultra-high frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, a trapezoidal groove 2 is located on the lower surface of the piezoelectric film, and the trapezoidal groove is located right below the interdigital electrode.

Example 5

Fig. 16-18 are schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 5:

in embodiment 5, the ultra-high frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, and trapezoidal grooves 2 are located on two sides of the interdigital electrode on the piezoelectric upper surface.

Example 6

Fig. 19-21 are schematic structural diagrams of the uhf resonator with adjustable effective electromechanical coupling coefficient in this embodiment 6:

in embodiment 6, the ultra-high frequency resonator structure with adjustable effective electromechanical coupling coefficient is composed of an interdigital electrode 3 and a piezoelectric film 1 from top to bottom, wherein a trapezoidal groove 2 is simultaneously located on the upper and lower surfaces of the piezoelectric film, the grooves on the upper surface of the piezoelectric film are located on the left and right sides of the interdigital electrode or under the electrode, and the grooves on the lower surface of the piezoelectric film are located under the interdigital electrode.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined by the appended claims.