CN101911482B - Surface acoustic wave device - Google Patents
Surface acoustic wave device Download PDFInfo
- Publication number
- CN101911482B CN101911482B CN2008801246798A CN200880124679A CN101911482B CN 101911482 B CN101911482 B CN 101911482B CN 2008801246798 A CN2008801246798 A CN 2008801246798A CN 200880124679 A CN200880124679 A CN 200880124679A CN 101911482 B CN101911482 B CN 101911482B
- Authority
- CN
- China
- Prior art keywords
- thickness
- sio
- situation
- film
- idt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 45
- 239000000758 substrate Substances 0.000 claims abstract description 41
- 239000007769 metal material Substances 0.000 claims abstract description 38
- 239000000956 alloy Substances 0.000 claims abstract description 8
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 8
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 41
- 229910013641 LiNbO 3 Inorganic materials 0.000 claims description 21
- 239000007772 electrode material Substances 0.000 claims description 9
- 229910010272 inorganic material Inorganic materials 0.000 claims description 4
- 239000011147 inorganic material Substances 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims 1
- 230000008878 coupling Effects 0.000 abstract description 40
- 238000010168 coupling process Methods 0.000 abstract description 40
- 238000005859 coupling reaction Methods 0.000 abstract description 40
- 229910003327 LiNbO3 Inorganic materials 0.000 abstract description 7
- 229910052802 copper Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 10
- 239000012467 final product Substances 0.000 description 10
- 229910052681 coesite Inorganic materials 0.000 description 5
- 229910052906 cristobalite Inorganic materials 0.000 description 5
- 239000000377 silicon dioxide Substances 0.000 description 5
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 229910052682 stishovite Inorganic materials 0.000 description 5
- 229910052905 tridymite Inorganic materials 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 2
- -1 Au on the substrate Chemical class 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
- H03H9/02559—Characteristics of substrate, e.g. cutting angles of lithium niobate or lithium-tantalate substrates
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
- H03H9/02574—Characteristics of substrate, e.g. cutting angles of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14538—Formation
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
A surface acoustic wave device employing an LiNbO3 substrate, in which not only the reflection coefficient but also the electromechanical coupling coefficient k2 of an IDT are large, and the range of Euler angles of the LiNbO3 substrate for realizing a large electromechanical coupling coefficient k2 can be enlarged. Specifically disclosed is a surface acoustic wave device (1) wherein a plurality of grooves (2b) are formed in the upper surface (2a) of an LiNbO3 substrate (2), an IDT (3) having a plurality of electrode fingers composed of a metal material filling the plurality of grooves (2b) is provided, and the metal material is composed of Cu or an alloy principally comprising Cu.
Description
Technical field
For example the present invention relates to as harmonic oscillator or band pass filter and the surface acoustic wave apparatus that is used more specifically, relates to the surface acoustic wave apparatus with the structure that is formed with the IDT that is made of the Cu that fills in the groove on the voltage substrate.
Background technology
In the past, surface acoustic wave apparatus was employed more extensively as harmonic oscillator or band pass filter.The surface acoustic wave apparatus 100 of schematic drawing ground in Figure 16 (the slightly To of figure) expression cross-section structure is for example disclosed in following patent documentation 1.
In surface acoustic wave apparatus 1001, at LiNbO
3The upper surface 1002a of substrate 1002 is formed with many groove 1002b.In many groove 1002b, be filled with metal, form thus have the many strip electrodes that constituted by this metal and refer to that (Electricity Very refers to) ITD1003.By covering LiNbO
3The mode of the upper surface 1002a of substrate 1002 is laminated with SiO
2Film 1004.Because LiNbO
3 Substrate 1002 has negative frequency-temperature coefficient TCF, therefore by stacked SiO with positive frequency-temperature coefficient TCF
2Film 1004 and reduced the absolute value of the frequency-temperature coefficient TCF of surface acoustic wave apparatus 1001.
In addition, form IDT by being embedded in many metals among the groove 1002b, thereby in IDT, obtained bigger reflection coefficient.Particularly, show when the wavelength of setting surface wave is λ, the thickness setting of the IDT that the thickness of the Al that fills in groove 1002b namely is made of Al is under the situation of 0.04 λ, the reflection coefficient that each strip electrode refers to is 0.05, and the more big then resulting reflection coefficient of thickness of electrode is just more big.
On the other hand, the surface acoustic wave apparatus shown in Figure 17 is disclosed in following patent documentation 2.In surface acoustic wave apparatus 1101, by LiTaO
3Or LiNbO
3Be formed with IDT1103 on the piezoelectric substrate 1102 that constitutes.In addition, be formed with diaphragm 1104 by the mode that covers IDT1103.On the other hand, be formed with by SiO in the remaining area outside the part that is formed with IDT1103 and diaphragm 1104
2The first insulant layer 1105 that constitutes, its thickness equal that IDT1103 and diaphragm 1104 is stacked and the thickness of the laminated metal film that constitutes.And, make by SiO by the mode that covers the first insulant layer 1105
2The second insulant layer 1106 that constitutes is stacked.Here show as IDT1103 and also can suppress the situation of undesirable ripple (リ Star プ Le) by using the absolute value that can increase reflection coefficient than the bigger metal of Al density.
Patent documentation 1:WO2006/011417A1
Patent documentation 2:JP spy opens the 2004-112748 communique
The more big order (purport) that then more can increase the absolute value of reflection coefficient of the thickness that the IDT that is made of Al has been shown in the surface acoustic wave apparatus 1001 described in the patent documentation 1.But the absolute value that inventor's discovery of the application only increases reflection coefficient is to obtain good resonance characteristic.Namely, discovery is in the surface acoustic wave apparatus described in the patent documentation 1, though by the thickness of the electrode that is made of Al is thickeied and can increase the absolute value of reflection coefficient, but because the symbol of reflection coefficient is negative value, can not in passband, produces a plurality of ripples and obtain good resonance characteristic.
In patent documentation 1, about the thickness of IDT and the relation between the reflection coefficient, only illustrated at LiTaO
3Use the situation of the IDT that is constituted by Al on the substrate.In addition, in the paragraph 0129 of patent documentation 1, hint (show and instigate) has at LiNbO
3Also can use the order that is formed IDT by other metals such as Au on the substrate, but only disclose the IDT that is constituted by Au.
On the other hand, in patent documentation 2, as mentioned above, under the situation of using the IDT that is constituted by the metal bigger than Al density, though show the order of the absolute value that can improve reflection coefficient, but aspect the electromechanical coupling factor that can increase the gained surface acoustic wave apparatus, do not mention especially.
In addition, at above-mentioned LiNbO
3In the IDT structure of filling Au in the groove that arranges on the substrate and forming, there is following problem, that is: for obtaining fully big electromechanical coupling factor k
2, the LiNbO that can use
3The Eulerian angles scope of substrate is narrower.
Summary of the invention
The objective of the invention is to, a kind of surface acoustic wave apparatus is provided, this surface acoustic wave apparatus is eliminated the shortcoming of conventional art, uses LiNbO as piezoelectric substrate
3Substrate, and not only the reflection coefficient of IDT is fully big but also electromechanical coupling factor k
2Also bigger, can use LiNbO
3The Eulerian angles scope of substrate relatively is wide, and can improve design freedom.
According to the present invention, a kind of surface acoustic wave apparatus is provided, it is characterized in that possessing: piezoelectric substrate, it is by LiNbO
3Substrate constitutes and is formed with many grooves at upper surface; IDT, it has the many strip electrodes that are made of the metal material of filling and refers in many grooves of described piezoelectric substrate upper surface, and described metal material constitutes by Cu or based on the alloy of Cu.
In surface acoustic wave apparatus involved in the present invention, wavelength at the setting elastic surface wave is under the situation of λ, the θ of the electrode thickness of described IDT and the Eulerian angles of described LiNbO3 substrate (0 ° ± 10 °, θ, 0 ° ± 10 °) is a kind of of combination shown in the following table 1.At this moment, can further enlarge the Eulerian angles scope of the LiNbO3 substrate that can obtain big electromechanical coupling factor k2.
[table 1]
| Electrode material | The electrode thickness | The θ of Eulerian angles |
| Cu | 0.02λ≤Cu≤0.04λ | 70°≤θ≤145° |
| Cu | 0.04λ＜Cu≤0.08λ | 70°≤θ≤151° |
In addition, in surface acoustic wave apparatus involved in the present invention, preferably also possess dielectric film, it covers described IDT and described piezoelectric substrate and is that the inorganic material of main component constitutes by SiO2 or with SiO2.At this moment, by SiO2 or with SiO2 be the dielectric film that constitutes of the inorganic material of main component frequency-temperature coefficient on the occasion of, the frequency-temperature coefficient TCF of LiNbO3 is negative value, therefore can be provided as the less surface acoustic wave apparatus of absolute value of overall frequency temperature coefficient TCF.
Of the present invention other specific aspect, be under the situation of λ in the wavelength set with described elastic surface wave, described IDT comes standardization thickness that standardization forms, comes (0 ° ± 10 ° of the Eulerian angles of the standardization thickness that standardization forms, described LiNbO3 substrate as the SiO2 film of described dielectric film with λ with λ, θ, 0 ° ± 10 °) θ be a kind of of the combination shown in following table 2～table 4.
[table 2]
[table 2]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
[table 3]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
[table 4]
[table 4]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
(invention effect)
According to the present invention, have by LiNbO
3Among the IDT that the Cu that fills in the groove of the upper surface of substrate or the many strip electrodes that constitute based on the alloy of Cu refer to, metal material is made of above-mentioned specific metal, and therefore not only the reflection coefficient of IDT is big but also can obtain bigger electromechanical coupling factor k
2And, for realizing above-mentioned electromechanical coupling factor k
2Bigger scope can be selected LiNbO from wideer scope
3The Eulerian angles of substrate.Therefore, the characteristic of surface acoustic wave apparatus not only can be improved, and the design freedom of surface acoustic wave apparatus can be improved.
Description of drawings
Fig. 1 (a) reaches the main pseudosection of schematic part of the major part that (b) is the related surface acoustic wave apparatus of expression one embodiment of the present invention, (b) is the schematic plan of this surface acoustic wave apparatus.
Fig. 2 represents in one embodiment of the present invention to use as the metal material that constitutes IDT between the θ of the Eulerian angles under the situation of Cu and the reflection coefficient to concern that solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
Fig. 3 is θ and the electromechanical coupling factor k that represents in one embodiment of the present invention to use as the metal material that constitutes IDT the Eulerian angles under the situation of Cu
2Between the relation, solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
Fig. 4 is illustrated between the θ of the Eulerian angles under the situation of using Al in the example in the past as the metal material that constitutes IDT and the reflection coefficient to concern that solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
Fig. 5 is θ and the electromechanical coupling factor k that is illustrated in the Eulerian angles under the situation of using Al in the example in the past as the metal material that constitutes IDT
2Between the relation, solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
Fig. 6 is illustrated in the θ of the Eulerian angles under the situation of using Au in the example in the past as the metal material that constitutes IDT and the relation between the reflection coefficient, and solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
Fig. 7 is θ and the electromechanical coupling factor k that is illustrated in the Eulerian angles under the situation of using Au in the example in the past as the metal material that constitutes IDT
2Between relation, solid line is to be illustrated in to be laminated with SiO
2Result under the situation of the structure of film, dotted line is to be illustrated in not have stacked SiO
2Result under the situation of the structure of film.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and do not form SiO as the metal material that constitutes IDT that Fig. 8 (a) reaches
2The standardization thickness of the Cu film under the situation of film, the θ of Eulerian angles, reflection coefficient and electromechanical coupling factor k
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Fig. 9 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.05 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 10 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.1 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 11 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.15 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 12 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.2 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 13 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.25 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 14 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.3 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
It (b) is to be illustrated respectively in the one embodiment of the present invention to use Cu and SiO as the metal material that constitutes IDT that Figure 15 (a) reaches
2The standardization thickness of film is the standardization thickness of the Cu film under 0.35 the situation, θ, reflection coefficient and the electromechanical coupling factor k of Eulerian angles
2Between the relation figure.
Figure 16 is the schematic main pseudosection for an example of explanation Surface Wave Device in the past.
Figure 17 is other routine main pseudosection of part notch (cut and owe) of representing Surface Wave Device in the past.
Among the figure: 1-surface acoustic wave apparatus, 2-LiNbO
3Substrate, 2a-upper surface, 2b-groove, 3-IDT, 4-SiO
2Film, 5, the 6-reflector.
Embodiment
Below, with reference to accompanying drawing the specific embodiment of the present invention is described, thereby make the present invention become clear.
It is the main pseudosection of schematic part of the part that is formed with IDT of the related surface acoustic wave apparatus of one embodiment of the present invention that Fig. 1 (a) reaches (b), (b) is the schematic plan of this surface acoustic wave apparatus.
As shown in Fig. 1 (a), surface acoustic wave apparatus 1 has LiNbO
3Substrate 2.At LiNbO
3The upper surface 2a of substrate 2 is formed with many groove 2b.In many groove 2b, fill metal, have the IDT3 that many strip electrodes refer to thereby form.The upper surface of this IDT3 and LiNbO
3The upper surface 2a of substrate 2 is a plane.
Form SiO by the mode that covers upper surface 2a and IDT3
2Film 4.In addition, do not form SiO in the present invention
2Film 4 also can.
As shown in Fig. 1 (b), surface acoustic wave apparatus 1 is to have above-mentioned IDT3 and be configured in first, second reflector 5 of the surface wave propagation direction both sides of IDT3,61 port type (Port one ト type) elastic wave resonant's.In addition, reflector 5,6 is respectively diffraction grating (the グ レ one テ イ Application グ) reflector that two terminal shortcircuits that many strip electrodes are referred to form.
The same with IDT3, state reflector 5,6 also by filling and being arranged on LiNbO
3The identical metal of many grooves of the upper surface 2a of substrate 2 forms.Therefore, in reflector 5,6, electrode surface and LiNbO
3The upper surface 2a of substrate 2 is roughly a plane.SiO thus
2The upper surface of film 4 spreads all over the whole of surface acoustic wave apparatus 1 and by general planarization.
Though LiNbO
3The frequency-temperature coefficient TCF of substrate 2 is negative value, but because SiO
2The frequency-temperature coefficient TCF of film 4 be on the occasion of, the absolute value of frequency-temperature coefficient TCF is less as a whole.The variation of the frequency characteristic that therefore, is produced by variations in temperature in surface acoustic wave apparatus is less.
The surface acoustic wave apparatus 1 of present embodiment is characterized in that for utilizing the surface acoustic wave apparatus of SH ripple, and the above-mentioned metal material that constitutes above-mentioned IDT3 forms by Cu or based on the alloy of Cu.Also can in above-mentioned IDT3, add and connect airtight the metal level that layer, diffusion prevent that layer etc. from being made of other metal material, also can be the stacked structure of above-mentioned IDT3 and other metal level in addition.
Thus, in the surface acoustic wave apparatus 1 of present embodiment, not only the absolute value of the reflection coefficient of IDT3 is big but also can obtains big electromechanical coupling factor k
2In addition, as shown in the following specific embodiment, when obtaining electromechanical coupling factor k
2During for bigger surface acoustic wave apparatus 1, can enlarge and to use LiNbO
3The Eulerian angles scope of substrate.Therefore, can improve design freedom.Be explained with reference to Fig. 2～Fig. 7.
Fig. 4 and Fig. 5 represent respectively to have with the same structure of the surface acoustic wave apparatus 1 of above-mentioned execution mode but are formed IDT electrode and reflector and utilized the LiNbO of the surface acoustic wave apparatus that leaks (leaking Vent) elastic surface wave by Al
3θ, reflection coefficient and the electromechanical coupling factor k of the Eulerian angles of substrate (0 °, θ, 0 °)
2Between the relation figure.
The standardization thickness that the surface wave wavelength X of the IDT3 that expression will be made of Al in Fig. 4 and Fig. 5 forms as standard is set at the result of 0.04 or 0.08 situation.In addition, representing to be formed with the standardization thickness by solid line is 0.25 SiO
2The result of the structure of film 4, and be illustrated by the broken lines and do not form SiO
2The result that the structure of film 4 is relevant.
Known to from Fig. 4, reflection coefficient improves hardly under the situation of using Al as electrode material.
In addition, known to from Fig. 5, change and can make electromechanical coupling factor k by the θ to Eulerian angles
2Be increased to more than 0.2.But, as shown in Figure 4, do not forming SiO as can be known
2Under the situation of film 4, no matter the thickness of the θ value of Eulerian angles and the IDT that is made of Al how, reflection coefficient is the little value below 0.1.
On the other hand, Fig. 6 and Fig. 7 be that expression uses as electrode material with the surface wave wavelength X are the result of the situation of 0.04 or 0.08 Au as the standardization thickness of standard.That is, expression is formed the result of the IDT electrode 3 shown in Fig. 1 and reflector 5,6 situation by Au.Fig. 6 concerns between the expression θ of Eulerian angles and the reflection coefficient that Fig. 7 is θ and the electromechanical coupling factor k of expression Eulerian angles
2Between the relation.
In addition, in Fig. 6 and Fig. 7, having represented to be formed with the standardization thickness by solid line is 0.25 SiO
2The result of the structure of film 4 has been illustrated by the broken lines the result of inchoate structure.
As known from Figure 6, using under the situation of Au as electrode material, comparing with the situation of using the electrode material Al shown in Fig. 4, no matter how Eulerian angles θ is for improving reflection coefficient.
But, as shown in Figure 7, electromechanical coupling factor k
2Bigger zone, i.e. electromechanical coupling factor k
2Zone greater than 0.2 is not form SiO under 0.04 the situation at the electrode standardization thickness that is made of Au
2Be in the structure of film 4 in 72 °～131 ° the scope, the electrode standardization thickness that is made of Au is to be under 0.08 the situation in 85 °～119 ° the scope.Therefore, under the situation about in 0.04～0.08 scope, the standardization thickness being changed, if in 85 °～119 ° scope, do not select the θ of Eulerian angles, then can not make electromechanical coupling factor k as can be known
2Be increased to more than 0.2.
As can be known, forming the IDT3 that constituted by Au and reflector 5,6 and also be formed with SiO
2In the structure of film 4, in order to make electromechanical coupling factor k
2Become more than 0.2, must be under 0.04 the situation θ of Eulerian angles to be set at 77 °～117 ° scope at the standardization thickness of Au film and be under 0.08 the situation θ of Eulerian angles to be set at 90 °～114 ° scopes at the standardization thickness.Therefore, as can be known at SiO
2The standardization thickness of film 4 is that the θ of Eulerian angles must be in 90 °～114 ° scopes in 0.04～0.08 the scope.
With respect to this, as described below, use Cu as the metal material that constitutes IDT3 or with the situation of Cu as the alloy of main body under, can enlarge and can make electromechanical coupling factor k
2Become the Eulerian angles scope more than 0.2.Therefore, can improve the design freedom of surface acoustic wave apparatus.
In addition, why at electromechanical coupling factor k
2Be to be that good reason is under the situation more than 0.2, in the Surface Wave Device that is used being used as harmonic oscillator or band pass filter, for obtaining common desired bandwidth (the band territory width of cloth), preferred electromechanical coupling factor k
2For about more than 0.2.
(using the situation of Cu as metal material)
Fig. 2 and Fig. 3 are θ, reflection coefficient and the electromechanical coupling factor k of expression Eulerian angles
2Between the relation figure.Standardization thickness as the Cu that constitutes IDT3 and reflector 5,6 metal material in Fig. 2 and Fig. 3 is 0.02,0.04 or 0.08.And, in Fig. 2 and Fig. 3, represented to be formed with SiO by solid line
2The result of the situation of film 4 has been illustrated by the broken lines and has not formed SiO
2The result of the situation of film 4.
Known to from Fig. 2, using under the situation of Cu as metal material, no matter the scope of the θ of Eulerian angles how, is compared with the situation of using Al, can access bigger reflection coefficient.
In addition, known to from Fig. 3, do not forming SiO
2In the structure of film 4, can make electromechanical coupling factor k
2Become the Eulerian angles scope more than 0.2, be to be that 70 °～145 ° scope gets final product under 0.02 the situation at the standardization thickness of Cu film, be to be that 70 °～151 ° scope gets final product under 0.04 the situation at the standardization thickness, and be to be that 70 °～156 ° scope gets final product under 0.08 the situation at the standardization thickness.Therefore, using as metal material under the situation of Cu as can be known, the θ of Eulerian angles is more than 70 °, below 145 ° under the situation in its thickness is in the scope of 0.02 λ～0.04 λ, and surpasses 0.04 λ and be that the θ of Eulerian angles under the situation below 0.08 λ is that scope more than 70 °, below 151 ° gets final product at its thickness.Therefore, compare with the scope more than 85 °, below 119 ° of the situation of using Au, can enlarge the scope of the θ of Eulerian angles.Equally, as can be known from Fig. 3, be laminated with SiO
2In the structure of film 4, can make electromechanical coupling factor k
2Becoming the Eulerian angles scope more than 0.2, is to be 83 °～124 ° under the situation of 0.02 λ at the thickness of Cu, is to be 82 °～137 ° under the situation of 0.04 λ at thickness, at thickness is to be 79 °～124 ° under the situation of 0.08 λ to get final product.That is, the θ of Eulerian angles is more than 83 °, below 124 ° under the situation in the thickness of Cu is in the scope of 0.02 λ～0.04 λ as can be known, in that to surpass 0.04 λ and be more than 82 ° under the situation below 0.08 λ, get final product below 124 °.Therefore, compare with the scope more than 90 °, below 119 ° of the situation of using Au, can enlarge the scope of the θ of Eulerian angles.
Summary constitutes electromechanical coupling factor k with reference to the illustrated result of Fig. 2～Fig. 7
2The electrode thickness that is the metal material of the electrode more than 0.2, is made of this metal material, the θ of Eulerian angles are combined into a kind of of combination shown in the following table 5.Table 5 is that expression does not have stacked SiO
2The result of the situation of the structure of film.
[table 5]
| Electrode material | The electrode thickness | The θ of Eulerian angles |
| Cu | 0.02λ≤Cu≤0.04λ | 70°≤θ≤145° |
| Cu | 0.04λ＜Cu≤0.08λ | 70°≤θ≤151° |
| Au | 0.04λ≤Au≤0.08λ | 85°≤θ≤119° |
In table 5, for comparing, represent to use as metal material the situation of Au in the lump.
[be formed with SiO
2Electrode thickness under the situation of film, SiO
2The combination of the standardization thickness of film, the θ scope of Eulerian angles]
In above-mentioned table 5, do not forming SiO
2Represented electromechanical coupling factor k by each electrode material under the situation of film
2Be electrode thickness more than 0.2 and the θ scope of Eulerian angles.
And the application's inventor is with SiO
2Film is in dielectric film and the such structure that forms that covers the IDT electrode, except electrode material, electrode thickness, also considers SiO
2The standardization thickness of film is to electromechanical coupling factor k
2The scope that is each θ of the Eulerian angles more than 0.2 is studied.Its result is described by each metal material following.
(form SiO
2Film also uses the situation of Cu as metal material)
Fig. 8 (a) and (b)～Figure 15 (a) and (b) are to be illustrated respectively in as metal material to use Cu and be formed with SiO with various standardization thickness
2The θ of the Eulerian angles under the situation of film, reflection coefficient and electromechanical coupling factor k
2Between the relation figure.
In addition, Fig. 8 (a) and (b) are to be illustrated in SiO
2The standardization thickness of film is 0 namely not form SiO
2Result under the situation of film, Fig. 9～Figure 15 are illustrated in SiO
2The standardization thickness of film is respectively the result under 0.05,0.1,0.15,0.2,0.25,0.3 and 0.35 the situation.In addition, the standardization thickness of setting as the Cu that constitutes IDT3 and reflector 5,6 metal material is all thickness as shown in Fig. 8～Figure 15.Shown in described Fig. 2, using under the situation of Cu as metal material, no matter the θ scope of Eulerian angles how, is compared with the situation of using Al, can access bigger reflection coefficient.In Fig. 8 (a)～Figure 15 (a) as can be known, no matter the θ value of Eulerian angles is how, even and the Cu film is being carried out can both obtain bigger reflection coefficient under the situation of various variations.
On the other hand, known to from Fig. 8 (b)～Figure 15 (b), under the standardization thickness of Cu is in situation in 0.04～0.08 the scope, if with SiO
2The standardization thickness of film and the θ scope of Eulerian angles are set at a kind of of the combination shown in the following table 6, then can make electromechanical coupling factor k
2Become more than 0.2.In addition, lower limit and the higher limit of the θ scope of expression Eulerian angles in following table 6.For example, be illustrated in SiO
2The thickness of film is that the θ of Eulerian angles is more than 70 ° and the scope below 151 ° gets final product under the situation below 0.05.
In addition, at the standardization thickness of Cu film greater than 0.08 and be under the situation below 0.12, SiO
2The scope of the thickness of film and the θ of Eulerian angles is a kind of the getting final product of combination shown in the following table 7; At the standardization thickness of Cu film greater than 0.12 and be under the situation below 0.16, SiO
2The scope of the thickness of film and the θ of Eulerian angles is a kind of get final product of combination shown in the following table 8, equally, can make electromechanical coupling factor k
2Become more than 0.2.This table 6～table 8 is based on the result of above-mentioned Fig. 8～Figure 15.
[table 6]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
[table 7]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
[table 8]
(Cu thickness and SiO in the table
2Thickness is represented each standardization thickness * 10
2Value.)
(about alloy)
As mentioned above, when forming the IDT electrode, at LiNbO
3Fill metal material in the groove that the upper surface of substrate is set up.At this moment, above-mentioned metal material is not limited to above-mentioned Cu, also can be the alloy based on Cu.
In addition, in the above-described embodiments, be formed with SiO as dielectric film
2Film, but be not limited to SiO
2Film also can be by with SiO
2Film is the dielectric film that the inorganic material of main component constitutes.No matter form any dielectric film and since these dielectric film medium frequency temperatures coefficient be on the occasion of, so can by with frequency-temperature coefficient be the LiNbO of negative value
3Substrate makes up and reduces the absolute value of the frequency-temperature coefficient of surface acoustic wave apparatus.That is, can provide temperature characterisitic better elastic Surface Wave Device.
In addition, by this electrode structure of inventing formed surface acoustic wave apparatus, be not limited to the structure shown in Fig. 1, the present invention can be applicable in elastic wave resonant's of various electrode structures or acoustic surface wave filter etc.
In addition, as mentioned above, in the present application, represented LiNbO
3Eulerian angles (φ, θ ψ) are not subjected to the special order that limits, but in order to utilize Rayleigh wave (レ イ リ one ripple) and SH ripple as surface wave, the φ that preferably sets Eulerian angles is 0 ° ± 10 ° scope, and θ is 70 °～180 ° scope, and ψ is 0 ° ± 10 ° scope.That is, by in Eulerian angles, setting the scope of (0 ° ± 10 °, 70 °～180 °, 0 ° ± 10 °), and can suitably use Rayleigh to involve the SH ripple.More specifically, can in the scope of (0 ° ± 10 °, 90 °～180 °, 0 ° ± 10 °), further suitably utilize the SH ripple.
In addition, also can use the LSAW ripple, set Eulerian angles this moment and get final product for the scope of (0 ° ± 10 °, 110 °～160 °, 0 ° ± 10 °).In addition, in the above-described embodiment, shown the electrode structure of 1 port type SAW harmonic oscillator, and surface acoustic wave apparatus of the present invention can be widely applicable in other resonator structure or other resonator-type acoustic surface wave filter.
Claims (3)
1. a surface acoustic wave apparatus is characterized in that,
Possess:
Piezoelectric substrate, it is by LiNbO
3Substrate constitutes, and is formed with many grooves at upper surface;
IDT, it has the many strip electrodes that are made of the metal material of filling and refers in many grooves of the upper surface of described piezoelectric substrate,
Described metal material constitutes by Cu or based on the alloy of Cu,
Wavelength at the setting elastic surface wave is under the situation of λ, the electrode thickness of described IDT and described LiNbO
3The θ of the Eulerian angles of substrate (0 ° ± 10 °, θ, 0 ° ± 10 °) is a kind of of the combination shown in the following table 1,
[table 1]
。
2. surface acoustic wave apparatus according to claim 1 is characterized in that,
Also possess:
Dielectric film, it covers described IDT and described piezoelectric substrate, and by SiO
2Or with SiO
2Inorganic material formation for main component.
3. surface acoustic wave apparatus according to claim 2 is characterized in that,
Be under the situation of λ at the wavelength of setting described elastic surface wave, described IDT with λ come standardization thickness that standardization forms, as the SiO of described dielectric film
2The standardization thickness, the described LiNbO that come standardization to form with λ of film
3The θ of the Eulerian angles of substrate (0 ° ± 10 °, θ, 0 ° ± 10 °) is a kind of of combination shown in following table 2～table 4,
[table 2]
* Cu thickness and SiO in showing
2Thickness is represented each standardization thickness * 10
2Value,
[table 3]
* Cu thickness and SiO in showing
2Thickness is represented each standardization thickness * 10
2Value,
[table 4]
* Cu thickness and SiO in showing
2Thickness is represented each standardization thickness * 10
2Value.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008-008350 | 2008-01-17 | ||
| JP2008008350 | 2008-01-17 | ||
| JP2008-207765 | 2008-08-12 | ||
| JP2008207765 | 2008-08-12 | ||
| PCT/JP2008/003882 WO2009090713A1 (en) | 2008-01-17 | 2008-12-22 | Surface acoustic wave device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101911482A CN101911482A (en) | 2010-12-08 |
| CN101911482B true CN101911482B (en) | 2013-09-04 |
Family
ID=40885124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008801246798A Active CN101911482B (en) | 2008-01-17 | 2008-12-22 | Surface acoustic wave device |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPWO2009090713A1 (en) |
| CN (1) | CN101911482B (en) |
| WO (1) | WO2009090713A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102217820B1 (en) * | 2016-11-17 | 2021-02-18 | 가부시키가이샤 무라타 세이사쿠쇼 | Acoustic wave device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5248375U (en) * | 1975-10-02 | 1977-04-06 | ||
| JP2783550B2 (en) * | 1988-07-27 | 1998-08-06 | 富士通株式会社 | Surface acoustic wave oscillator |
| JPH0983030A (en) * | 1995-09-11 | 1997-03-28 | Matsushita Electric Ind Co Ltd | Surface acoustic wave element and fabrication thereof |
| JP2006013576A (en) * | 2004-06-22 | 2006-01-12 | Epson Toyocom Corp | Saw device and apparatus employing the same |
| JP4483865B2 (en) * | 2004-07-26 | 2010-06-16 | 株式会社村田製作所 | Surface acoustic wave device |
-
2008
- 2008-12-22 WO PCT/JP2008/003882 patent/WO2009090713A1/en active Application Filing
- 2008-12-22 JP JP2009549908A patent/JPWO2009090713A1/en active Pending
- 2008-12-22 CN CN2008801246798A patent/CN101911482B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN101911482A (en) | 2010-12-08 |
| JPWO2009090713A1 (en) | 2011-05-26 |
| WO2009090713A1 (en) | 2009-07-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6882929B2 (en) | Elastic wave resonators, filters and multiplexers | |
| US9035725B2 (en) | Acoustic wave device | |
| US10862020B2 (en) | Elastic wave device | |
| CN103004085B (en) | Ladder-type elastic wave filter and antenna duplexer using same | |
| US7423365B2 (en) | Surface acoustic wave device | |
| US8680744B2 (en) | Surface acoustic wave device | |
| JP5690711B2 (en) | Elastic wave element | |
| US20080315973A1 (en) | Surface acoustic wave filter, boundary acoustic wave filter, and antenna duplexer using same | |
| JP7278305B2 (en) | Acoustic wave device, branching filter and communication device | |
| CN110710106B (en) | Elastic wave device, demultiplexer, and communication device | |
| JPWO2010131450A1 (en) | Antenna duplexer | |
| CN101385240A (en) | Elastic surface wave device | |
| JP5891198B2 (en) | Antenna duplexer and electronic device using the same | |
| WO2019022236A1 (en) | Elastic wave device, duplexer, and communication device | |
| JP2019021997A (en) | Acoustic wave element, splitter, and communication device | |
| US20220393665A1 (en) | Acoustic wave device | |
| WO2007145056A1 (en) | Surface acoustic wave device | |
| WO2007125733A1 (en) | Elastic surface wave device | |
| CN101911484B (en) | Surface acoustic wave device | |
| JP5110091B2 (en) | Surface acoustic wave device | |
| CN101911483A (en) | Surface acoustic wave device | |
| JP5671713B2 (en) | Elastic wave device | |
| CN101911482B (en) | Surface acoustic wave device | |
| JP4967393B2 (en) | Surface acoustic wave device | |
| WO2010137648A1 (en) | Ladder-type filter and acoustic wave resonator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |