CN1112763C

CN1112763C - Surface acoustic wave device

Info

Publication number: CN1112763C
Application number: CN97191459A
Authority: CN
Inventors: 井上宪司; 佐藤胜男
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 1996-10-18
Filing date: 1997-10-16
Publication date: 2003-06-25
Anticipated expiration: 2017-10-16
Also published as: CN1206517A

Abstract

The size of a surface acoustic wave device having a substrate and an interdigital electrodes on the surface of the substrate is reduced and the selectivity of the device is improved, and then, the band of the device is widened. For this purpose: (i) a piezoelectric film is formed to cover the surface of the substrate and interdigital electrodes, or (ii) a piezoelectric film is provided on the surface of the substrate and the interdigital electrodes are formed on the surface of the film. Alternatively, (iii) the piezoelectric film is provided on the surfaces of the substrate and interdigital electrodes and a counter electrode film is formed on the surface of the piezoelectric film, or (iiii) the counter electrode film is provided on the surface of the substrate and the piezoelectric film is formed on the counter electrode film and the interdigital electrodes are formed on the surface of the piezoelectric film. The piezoelectric film has a piezoelectric axis oriented nearly perpendicularly to the surface of the substrate.

Description

SAW (Surface Acoustic Wave) device

The present invention relates to a kind of SAW (Surface Acoustic Wave) device, it comprises: the interdigital electrode on the monocrystalline matrix.

In recent years, comprised the mobile communication terminal device of cellular phone, and popularized rapidly and come.For the ease of carrying, special hope reduces terminal equipment size and weight.Reduce the size and the weight of terminal equipment, just must reduce the size and the weight of its electronic unit.SAW (Surface Acoustic Wave) device helps reducing of size and weight, thereby the high frequency of terminal equipment and intermediate frequency parts usually adopt Surface Acoustic Wave Filter.SAW (Surface Acoustic Wave) device has an interdigital electrode on the surface of piezoelectric base unit, be used for exciting, receive, reflect and propagate surface acoustic wave.

The important characteristic parameter that is used for the piezoelectric base unit of SAW (Surface Acoustic Wave) device comprises: the temperature coefficient (TCF) and the electromechanical coupling factor (k of the surperficial velocity of wave of surface acoustic wave (SAW velocity of wave), filter center frequency resonator resonance frequency ²).What list in the table 1 is the characteristic parameter of the used different piezoelectric base units of existing SAW (Surface Acoustic Wave) device.In the back, these piezoelectric base units will be with the symbology that uses in the table 1.On this point, should be noted that TCV (being the temperature coefficient of surface acoustic wave velocity of wave) is a parameter of representing surface acoustic wave velocity of wave and temperature relation, represent the relation of centre frequency or resonance frequency and temperature as above-mentioned TCF.The value of TCV is big, means that the centre frequency of Surface Acoustic Wave Filter is subjected to the influence of temperature fluctuation big.

Table 1 symbol composition corner cut direction of propagation surface acoustic wave ripple k ²(%) TCV (ppm/ ℃)

Speed (m/s) 128LN LiNbO ₃128 °-rotation Y X, 3,992 5.5-7464LN LiNbO ₃64 °-rotation Y X, 4,742 11.3-79LT112 LiTaO ₃112 °-rotation of X Y, 3,288 0.64-1836LT LiTaO ₃36 °-rotation Y X, 4,212 4.7-45ST crystalline quartz ST X 3,158 0.14 0 (initial coefficients) BGO Bi ₁₂GeO ₂₀(100) (011) 1,681 1.2-122

As can be seen from Table 1, the surface acoustic wave velocity of wave of 64LN and 36LT is 4000m/s or higher, therefore is fit to make the high-frequency unit of terminal equipment.Consider this reason, at present the whole world is that the mobile communication of representative has adopted multiple systems with the cellular phone, and the frequency that adopts all is the order of magnitude of 1GHz.Correspondingly, about the centre frequency 1GHz of the filter of terminal equipment high-frequency unit.The centre frequency of Surface Acoustic Wave Filter.Substantially be directly proportional with the surface acoustic wave velocity of wave of used piezoelectric base unit, be inversely proportional to substantially with the finger width of the interdigital electrode that forms on the matrix.Therefore for this filter is worked, just preferably adopt matrix, under high frequency as 64LN and 36LT with high surface acoustic wave velocity of wave.And it is 20MHz or higher broad passband that the filter of high-frequency unit also should adopt width.But obtain such broad passband, just necessarily require piezoelectric base unit to have big electromechanical coupling factor k ²Owing to these reasons, 64LN and 36LT use a lot.

On the other hand, in mobile terminal device, use as intermediate frequency with the frequency band of 70～300MHz.When the filter that adopts this frequency band as centre frequency is used to make SAW (Surface Acoustic Wave) device, uses above-mentioned 64LN and 36LT to know from experience and cause the electrode finger width on the matrix to be far longer than the above-mentioned respective width that is used for the filter of high-frequency unit as piezoelectric based.

This point can be explained with reference to the particular value of rough calculation.If the d representative forms the electrode finger width of the surface acoustic wave transducer of Surface Acoustic Wave Filter, f ₀Represent the centre frequency of Surface Acoustic Wave Filter, the surface acoustic wave velocity of wave of the piezoelectric base unit that the V representative is adopted.These values satisfy formula (1) substantially:

f ₀=V/ (4d) ... (1) if be under the situation of 4000m/s, build the Surface Acoustic Wave Filter that its centre frequency is 1GHz, calculate electrode finger width according to formula (1) so and be at the velocity of wave of supposition surface acoustic wave:

d＝4,000(m/s)/[4×1,000(MHz)]＝1μm

On the other hand, if use this surface acoustic wave velocity of wave to build the intermediate-frequency filter of centre frequency as 100MHz as the piezoelectric base unit of 4000m/s, then the electrode finger width of its requirement is:

D=4,000 (m/s)/[4 * 100 (MHz)]=10 μ m as seen, its finger width is 10 times of high-frequency unit filter finger width.The increase of finger width means that the size of SAW (Surface Acoustic Wave) device also increases.Therefore, by above-mentioned formula (1) as can be seen, diminish, must adopt the little piezoelectric base unit of surface acoustic wave velocity of wave V in order to make the surface acoustic wave intermediate-frequency filter.

In the less piezoelectric base unit of existing surface acoustic wave velocity of wave, the BGO that mentions in the above-mentioned table 1 is arranged.The surface acoustic wave velocity of wave of BGO piezoelectric base unit is 1,681m/s, yet it and be not suitable for making the intermediate-frequency filter of separately a channel signals being separated because the temperature coefficient TCV of its SAW velocity of wave reaches-122ppm/ ℃.This is because TCV characterizes the relation of SAW velocity of wave and temperature, and the value of TCV means that greatly the centre frequency of Surface Acoustic Wave Filter is subjected to the influence of temperature fluctuation big, and these are mentioned in the above, and can find out from formula (1).Therefore big TCV is unfavorable to intermediate-frequency filter, because may take out the signal of not expecting from other channels adjacent with desired channel.

In the lower piezoelectric base unit of existing surface acoustic wave velocity of wave, also has the ST quartz crystal of mentioning in the above-mentioned table 1.Because the TCV of the quartzy prosperous body of ST almost nil (its initial temperature coefficient (primary temperature coefficient) a is zero), it is suitable for making intermediate-frequency filter.For this reason, up to now, the most of intermediate frequency Surface Acoustic Wave Filter that are used for mobile communication terminal device all are to make of ST quartz crystal piezoelectric base unit.

Yet the SAW velocity of wave of ST quartz crystal matrix is 3, and 158m/s is enough not low value in other words, thereby reduces to have produced certain restriction for size.

And, the electromechanical coupling factor k of quartzy prosperous body ²Be 0.14%, this value is quite little.Little k ²Value means the filter that can only obtain having narrow passband.At present, most cellular phones that adopt are the analogue systems with very narrow frequency bandwidth in the mobile communication.For example: the NTT standard of Japan is 12.5KHz, and the AMPS standard of the U.S. is 30KHz, and the TACS standard in Europe is 25KHz.Therefore, above-mentioned ST quartz crystal has little electromechanical coupling factor k ²This fact does not cause knotty problem in the past.In order to effectively utilize frequency resource and the compatibility of considering digital data communications, digital mobile communication system is developed, and uses and popularizes rapidly but in recent years.The channel bandwidth of this digital system is very big, is respectively 200KHz and 1.7MHz as European cellular phone GSM pattern and cordless telephone DECT pattern.Therefore, if make Surface Acoustic Wave Filter, just be difficult to make this Wideband Intermediate Frequency filter with ST quartz crystal matrix.

On the other hand, well-known, at LiNbO ₃Or form the piezoelectric film of forming by zinc oxide, lithia, Cds or similar compound on the piezoelectric base unit of similar substance, and can improve the electromechanical coupling factor of SAW (Surface Acoustic Wave) device, typically announce as JP-A8-204499.But, traditional piezoelectric base unit such as LiNbO ₃Be unsuitable for doing like this, because its temperature coefficient TCV is a negative value, therefore, when generating Zinc oxide film thereon, whole TCV value will turn to negative value side tempestuously.

As mentioned above, a problem of traditional SAW (Surface Acoustic Wave) device is, when piezoelectric base unit such as above-mentioned 64LN, 36LT etc. are used, its passband is broadened, but the high SAW velocity of wave of matrix but makes size of devices become big.Another problem is, when adopting the above-mentioned BGO matrix of low SAW velocity of wave in order to reduce device size, because the temperature coefficient TCV of SAW velocity of wave is too big, so can not get enough good selectivity.The characteristic parameter of the intermediate frequency Surface Acoustic Wave Filter that obtains under two kinds of situations is all good inadequately.

The quartzy prosperous body matrix of ST has little SAW velocity of wave temperature coefficient TCV, but because enough not little this fact of its SAW velocity of wave, and make size reduce be restricted; And because less this fact of its electromechanical coupling factor obtains difficulty of wide-band ratio.

Purpose of the present invention, one is: a kind of SAW (Surface Acoustic Wave) device is provided, has little size and enough good selectivity.It two is to provide a kind of SAW (Surface Acoustic Wave) device, has little size and wide passband.It three is to provide a kind of SAW (Surface Acoustic Wave) device, has little size, enough good selectivity and wide passband.

Above-mentioned purpose can be by any one realization among the following embodiment 1-4. Embodiment 1

(1) a kind of SAW (Surface Acoustic Wave) device comprises: the interdigital electrode on matrix, the matrix surface and cover the above-mentioned surface of above-mentioned matrix and the piezoelectric film on the surface of above-mentioned interdigital electrode.Wherein: above-mentioned matrix is langasite (lanthanum gallium silicon hydrochlorate) monocrystal that belongs to point group 32, and above-mentioned piezoelectric film is made up of zinc oxide.

(2) in (1) described SAW (Surface Acoustic Wave) device, above-mentioned piezoelectric film has a piezoelectric axis vertical substantially with the above-mentioned surface of above-mentioned matrix.

(3) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following regional l for φ, θ:

Area I:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜90°

(4) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-1 zone for φ, θ:

Area I-1

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜-70°

(5), the SAW (Surface Acoustic Wave) device in (4), satisfy:

h/λ＝0.2～0.8

Wherein, h is the thickness at the above-mentioned lip-deep above-mentioned piezoelectric film of above-mentioned matrix, and λ is the wavelength of above-mentioned surface acoustic wave.

(6) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-2 zone for φ, θ:

Area I-2,

-5°≤φ≤5°

85°≤θ≤95°

-70°≤ψ＜-50°

(7), the SAW (Surface Acoustic Wave) device in (6), satisfy:

h/λ＝0.25～0.7

(8) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-3 zone for φ, θ:

Area I-3,

-5°≤φ≤5°

85°≤θ≤95°

-50°≤ψ＜-35?°

(9), the SAW (Surface Acoustic Wave) device in (8), satisfy:

h/λ＝0.25-0.45

(10) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-4 zone for φ, θ:

Area I-4,

-5°≤φ≤5°

85°≤θ≤95°

-35°≤ψ＜-25°

(11), the SAW (Surface Acoustic Wave) device in (10), satisfy:

0＜h/λ≤0.5

(12) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-5 zone for φ, θ:

Area I-5,

-5°≤φ≤5°

85°≤θ≤95°

-25°≤ψ＜-10°

(13), the SAW (Surface Acoustic Wave) device in (12), satisfy:

0＜h/λ≤0.45

H is the thickness at the above-mentioned lip-deep above-mentioned piezoelectric film of above-mentioned matrix, and λ is the wavelength of above-mentioned surface acoustic wave.

(14) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-6 zone for φ, θ:

Area I-6,

-5°≤φ≤5°

85°≤θ≤95°

10°≤ψ＜25°

(15), the SAW (Surface Acoustic Wave) device in (14), satisfy:

0＜h/λ≤0.4

(16) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-7 zone for φ, θ:

Area I-7,

-5°≤φ≤5°

85°≤θ≤95?°

25°≤ψ＜35°

(17), the SAW (Surface Acoustic Wave) device in (16), satisfy:

0＜h/λ≤0.45

(18) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-8 zone for φ, θ:

Area I-8,

-5°≤φ≤5°

85°≤θ≤95°

35°≤ψ＜50°

(19), the SAW (Surface Acoustic Wave) device in (18), satisfy:

0＜h/λ≤0.4

(20) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-9 zone for φ, θ:

Area I-9,

-5°≤φ≤5°

85°≤θ≤95°

50°≤ψ＜70°

(21), the SAW (Surface Acoustic Wave) device in (20), satisfy:

0＜h/λ≤0.15～0.7

(22) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following I-10 zone for φ, θ:

Area I-10,

-5°≤φ≤5°

85°≤θ≤95°

70°≤ψ＜90°

(23), the SAW (Surface Acoustic Wave) device in (22), satisfy:

0＜h/λ≤0.15～0.8

Wherein, h is the thickness at the above-mentioned lip-deep above-mentioned piezoelectric film of above-mentioned matrix, and λ is the wavelength of above-mentioned surface acoustic wave. Embodiment 2

(1) a kind of SAW (Surface Acoustic Wave) device comprises: piezoelectric film that forms on matrix, the matrix surface and the interdigital electrode that forms on above-mentioned piezoelectric film surface.Wherein:

Above-mentioned matrix is the langasite monocrystal that belongs to point group 32, and above-mentioned piezoelectric film is made up of zinc oxide.

(3) in (1) described SAW (Surface Acoustic Wave) device, above-mentioned matrix corner cut that cuts out when above-mentioned monocrystal and the surface acoustic wave direction of propagation on above-mentioned matrix from langasite with Eulerian angles (ψ) during expression, φ, θ and ψ drop on following area I I for φ, θ:

Area I I:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜90°

(4) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-I:

Area I I-1:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜-70°

(5), the SAW (Surface Acoustic Wave) device in (4), satisfy:

h/λ＝0.05～0.8

Wherein, h is the thickness of above-mentioned piezoelectric film, and λ is the wavelength of above-mentioned surface acoustic wave.

(6) in (1) described SAW (Surface Acoustic Wave) device, above-mentioned matrix corner cut that cuts out when above-mentioned monocrystal and the surface acoustic wave direction of propagation on above-mentioned matrix from langasite with Eulerian angles (φ, θ, ψ) during expression, φ, θ and ψ drop on following area I I-2:

Area I I-2:

-5°≤φ≤5°

85°≤θ≤95°

-70°≤ψ＜-50°

(7), the SAW (Surface Acoustic Wave) device in (6), satisfy:

h/λ＝0.05～0.75

(8) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-3:

Area I I-3:

-5°≤φ≤5°

85°≤θ≤95°

-50°≤ψ＜-35°

(9), the SAW (Surface Acoustic Wave) device in (8), satisfy:

0＜h/λ≤0.45

(10) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-4:

Area I I-4,

-5°≤φ≤5°

85°≤θ≤95°

-35°≤ψ＜-25°

(11), the SAW (Surface Acoustic Wave) device in (10), satisfy:

0＜h/λ≤0.5

(12) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-5:

Area I I-5,

-5°≤φ≤5°

85°≤θ≤95°

-25°≤ψ＜-10°

(13), the SAW (Surface Acoustic Wave) device in (12), satisfy:

0＜h/λ≤0.45

H is the thickness of above-mentioned piezoelectric film, and λ is the wavelength of above-mentioned surface acoustic wave.

(14) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-6:

Area I I-6,

-5°≤φ≤5°

85°≤θ≤95°

10°≤ψ＜25°

(15), the SAW (Surface Acoustic Wave) device in (14), satisfy:

0＜h/λ≤0.4

Wherein, h is the thickness of the above-mentioned lip-deep above-mentioned piezoelectric film of above-mentioned matrix, and λ is the wavelength of above-mentioned surface acoustic wave.

(16) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-7:

Area I I-7:

-5°≤φ≤5°

85°≤θ≤95°

25°≤ψ＜35°

(17), the SAW (Surface Acoustic Wave) device in (16), satisfy:

0＜h/λ≤0.45

(18) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-8:

Area I I-8,

-5°≤φ≤5°

85°≤θ≤95°

35°≤ψ＜50°

(19), the SAW (Surface Acoustic Wave) device in (18), satisfy:

0＜h/λ≤0.4

(20) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-9:

Area I I-9,

-5°≤φ≤5°

85°≤θ≤95°

50°≤ψ＜70°

(21), the SAW (Surface Acoustic Wave) device in (20), satisfy:

h/λ＝0.05～0.7

(22) in (1) described surface acoustic wave falls part, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I I-10:

Area I I-10,

-5°≤φ≤5°

85°≤θ≤95°

70°≤ψ＜90°

(23), the SAW (Surface Acoustic Wave) device in (22), satisfy:

h/λ＝0.05～0.8

Wherein, h is the thickness of above-mentioned piezoelectric film, and λ is the wavelength of above-mentioned surface acoustic wave. Embodiment 3

(1) a kind of SAW (Surface Acoustic Wave) device comprises: matrix, in the interdigital electrode that forms on the matrix surface, cover above-mentioned surface and the piezoelectric film on above-mentioned interdigital electrode surface and the anti-phase electrode film on the above-mentioned piezoelectric film of above-mentioned matrix.Wherein:

Above-mentioned matrix is that the langasite monocrystal that belongs to point group 32, above-mentioned piezoelectric film are made up of zinc oxide.

(3) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following area I II for φ, θ:

Area I II:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜90°

(4) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-1:

Area I II-1:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜-70°

(5), the SAW (Surface Acoustic Wave) device in (4), satisfy:

0＜h/λ≤0.1

(6), the SAW (Surface Acoustic Wave) device in (4), satisfy:

h/λ＝0.3～0.8

(7) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-2:

Area I II-2:

-5°≤φ≤5°

85°≤θ≤95°

-70°≤ψ＜-50°

(8), the SAW (Surface Acoustic Wave) device in (7), satisfy:

0＜h/λ≤0.1

(9), the SAW (Surface Acoustic Wave) device in (7), satisfy:

h/λ＝0.35～0.8

(10) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-3:

Area I II-3:

-5°≤φ≤5°

85°≤θ≤95°

-50 °≤ψ＜-35 °, but except-30 °.

(11), the SAW (Surface Acoustic Wave) device in (10), satisfy:

0＜h/λ≤0.15

(12), the SAW (Surface Acoustic Wave) device in (10), satisfy:

h/λ＝0.35～0.5

(13) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-4:

Area I II-4:

-5°≤φ≤5°

85°≤θ≤95°

-35°≤ψ＜-25°

(14), the SAW (Surface Acoustic Wave) device in (13), satisfy:

0＜h/λ≤0.15

(15), the SAW (Surface Acoustic Wave) device in (13), satisfy:

h/λ＝0.3～0.5

(16) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-5:

Area I II-5:

-5°≤φ≤5°

85°≤θ≤95°

-25°≤ψ＜-10°

(17), the SAW (Surface Acoustic Wave) device in (16), satisfy:

0＜h/λ≤0.15

(18), the SAW (Surface Acoustic Wave) device in (16), satisfy:

h/λ＝0.3～0.45

(19) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-6:

Area I II-6:

-5°≤φ≤5°

85°≤θ≤95°

10°≤ψ＜25°

(20), the SAW (Surface Acoustic Wave) device in (19), satisfy:

0＜h/λ≤0.45

(21) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (when ψ) representing, φ, θ and ψ drop on following territory III-7 for φ, θ:

Area I II-7:

-5°≤φ≤5°

85°≤θ≤95°

25°≤ψ＜35°

(22), the SAW (Surface Acoustic Wave) device in (21), satisfy:

0＜h/λ≤0.5

(23) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-8:

Area I II-8:

-5°≤φ≤5°

85°≤θ≤95°

35°≤ψ＜50°

(24), the SAW (Surface Acoustic Wave) device in (23), satisfy:

0＜h/λ≤0.45

(25) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-9:

Area I II-9:

-5°≤φ≤5°

85°≤θ≤95°

50°≤ψ＜70°

(26), the SAW (Surface Acoustic Wave) device in (25), satisfy:

0＜h/λ≤0.05

(27), the SAW (Surface Acoustic Wave) device in (25), satisfy:

h/λ＝0.2～0.8

(28) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I II-10:

Area I II-10:

-5°≤φ≤5°

85°≤θ≤95°

70°≤ψ＜90°

(29), the SAW (Surface Acoustic Wave) device in (28), satisfy:

0＜h/λ≤0.05

(30), the SAW (Surface Acoustic Wave) device in (28), satisfy:

h/λ＝0.25～0.8

Wherein, h is the thickness of the above-mentioned lip-deep above-mentioned piezoelectric film of above-mentioned matrix, and λ is the wavelength of above-mentioned surface acoustic wave. Embodiment 4

(1) a kind of SAW (Surface Acoustic Wave) device comprises: the counter electrode films that forms on matrix, the matrix surface, the interdigital electrode that forms on piezoelectric film that forms on the counter electrode films and the piezoelectric film.Wherein:

(3) in (1) described SAW (Surface Acoustic Wave) device, above-mentioned matrix corner cut that cuts out when above-mentioned monocrystal and the surface acoustic wave direction of propagation on above-mentioned matrix from langasite with Eulerian angles (ψ) during expression, φ, θ and ψ drop on following area I V for φ, θ:

Area I V:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜90°

(4) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-1:

Area I V-1:

-5°≤φ≤5°

85°≤θ≤95°

-90°≤ψ＜-70°

(5), the SAW (Surface Acoustic Wave) device in (4), satisfy:

h/λ＝0.05～0.8

(6) in (1) described SAW (Surface Acoustic Wave) device, above-mentioned matrix corner cut that cuts out when above-mentioned monocrystal and the surface acoustic wave direction of propagation on above-mentioned matrix from langasite with Eulerian angles (φ, θ, ψ) during expression, φ, θ and ψ drop on following area I V-2:

Area I V-2:

-5°≤φ≤5°

85°≤θ≤95°

-70°≤ψ＜-50°

(7), the SAW (Surface Acoustic Wave) device in (6), satisfy:

h/λ＝0.05～0.8

(8) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-3:

Area I V-3:

-5°≤φ≤5°

85°≤θ≤95°

-50°≤ψ＜-35°

(9), the SAW (Surface Acoustic Wave) device in (8), satisfy:

h/λ＝0.05～0.45

(10) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-4:

Area I V-4:

-5°≤φ≤5°

85°≤θ≤95°

-35°≤ψ＜-25°

(11), the SAW (Surface Acoustic Wave) device in (10), satisfy:

h/λ＝0.05～0.5

(12) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-5:

Area I V-5:

-5°≤φ≤5°

85°≤θ≤95°

-25°≤ψ＜-10°

(13), the SAW (Surface Acoustic Wave) device in (12), satisfy:

h/λ＝0.05～0.45

(14) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-6:

Area I V-6:

-5°≤φ≤5°

85°≤θ≤95°

10°≤ψ＜25°

(15), the SAW (Surface Acoustic Wave) device in (14), satisfy:

h/λ＝0.05～0.45

(16) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-7:

Area I V-7:

-5°≤φ≤5°

85°≤θ≤95°

25°≤ψ＜35°

(17), the SAW (Surface Acoustic Wave) device in (16), satisfy:

h/λ＝0.05～0.5

(18) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-8:

Area I V-8:

-5°≤φ≤5°

85°≤θ≤95°

35°≤ψ＜50°

(19), the SAW (Surface Acoustic Wave) device in (18), satisfy:

h/λ＝0.05～0.45

(20) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-9:

Area I V-9:

-5°≤φ≤5°

85°≤θ≤95°

50°≤ψ＜70°

(21), the SAW (Surface Acoustic Wave) device in (20), satisfy:

0＜h/λ≤0.05～0.8

(22) in (1) described SAW (Surface Acoustic Wave) device, the Eulerian angles of the direction of propagation on above-mentioned matrix when above-mentioned matrix corner cut that cuts out from the langasite monocrystal and surface acoustic wave (φ, θ, when ψ) representing, φ, θ and ψ drop on following area I V-10:

Area I V-10:

-5°≤φ≤5°

85°≤θ≤95°

70°≤ψ＜90°

(23), the SAW (Surface Acoustic Wave) device in (22), satisfy:

0＜h/λ≤0.05～0.8

Fig. 1 is the sectional view according to the typical structure of the SAW (Surface Acoustic Wave) device of the embodiment of the invention 1.

Fig. 2 A, 2B, 2C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-1 and form in its surface.Fig. 2 A, 2B, 2C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 3 A, 3B, 3C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-2 and form in its surface.Fig. 3 A, 3B, 3C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 4 A, 4B, 4C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-3 and form in its surface.Fig. 4 A, 4B, 4C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 5 A, 5B, 5C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-4 and form in its surface.Fig. 5 A, 5B, 5C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 6 A, 6B, 6C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-5 and form in its surface.Fig. 6 A, 6B, 6C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 7 A, 7B, 7C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-6 and form in its surface.Fig. 7 A, 7B, 7C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 8 A, 8B, 8C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-7 and form in its surface.Fig. 8 A, 8B, 8C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Fig. 9 A, 9B, 9C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-8 and form in its surface.Fig. 9 A, 9B, 9C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 10 A, 10B, 10C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-9 and form in its surface.Figure 10 A, 10B, 10C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 11 A, 11B, 11C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and this SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-10 and form in its surface.Figure 11 A, 11B, 11C are respectively SAW velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 12 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-1 and form in its surface.

Figure 13 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-1 and form in its surface.

Figure 14 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-10 and form in its surface.

Figure 15 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: the ZnO film that utilizes the langasite monocrystalline matrix of area I-10 and form in its surface.

Figure 16 is the sectional view according to the typical structure of the SAW (Surface Acoustic Wave) device of the embodiment of the invention 2.

Figure 17 A, 17B, 17C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-1 and form in its surface.Figure 17 A, 17B, 17C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 18 A, 18B, 18C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-2 and form in its surface.Figure 18 A, 18B, 18C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 19 A, 19B, 19C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-3 and form in its surface.Figure 19 A, 19B, 19C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 20 A, 20B, 20C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the angle summary schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-4 and form in its surface.Figure 20 A, 20B, 20C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 21 A, 21B, 21C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-5 and form in its surface.Figure 21 A, 21B, 21C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 22 A, 22B, 22C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-6 and form in its surface.Figure 22 A, 22B, 22C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave)

Figure 23 A, 23B, 23C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-7 and form in its surface.Figure 23 A, 23B, 23C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 24 A, 24B, 24C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-8 and form in its surface.Figure 24 A, 24B, 24C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 25 A, 25B, 25C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-9 and form in its surface.Figure 25 A, 25B, 25C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 26 A, 26B, 26C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-10 and form in its surface.Figure 26 A, 26B, 26C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 27 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-1 and form in its surface.

Figure 28 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-1 and form in its surface.

Figure 29 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-10 and form in its surface.

Figure 30 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I I-10 and form in its surface.

Figure 31 is the sectional view according to the typical structure of the SAW (Surface Acoustic Wave) device of the embodiment of the invention 3.

Figure 32 A, 32B, 32C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-1 and form successively in its surface.Figure 32 A, 32B, 32C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 33 A, 33B, 33C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-2 and form successively in its surface.Figure 33 A, 33B, 33C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 34 A, 34B, 34C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-3 and form successively in its surface.Figure 34 A, 34B, 34C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 35 A, 35B, 35C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the angle summary schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-4 and form successively in its surface.Figure 35 A, 35B, 35C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 36 A, 36B, 36C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the angle summary schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-5 and form successively in its surface.Figure 36 A, 36B, 36C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 37 A, 37B, 37C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-6 and form successively in its surface.Figure 37 A, 37B, 37C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 38 A, 38B, 38C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-7 and form successively in its surface.Figure 38 A, 38B, 38C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 39 A, 39B, 39C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-8 and form successively in its surface.Figure 39 A, 39B, 39C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 40 A, 40B, 40C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-9 and form successively in its surface.Figure 40 A, 40B, 40C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 41 A, 41B, 41C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-10 and form successively in its surface.Figure 41 A, 41B, 41C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 42 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: interdigital electrode, ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-1 and form successively in its surface.

Figure 43 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-1 and form in its surface.

Figure 44 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-10 and form successively in its surface.

Figure 45 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: ZnO film and the counter electrode films utilizing the langasite monocrystalline matrix of area I II-10 and form successively in its surface.

Figure 46 is the sectional view according to the typical structure of the SAW (Surface Acoustic Wave) device of the embodiment of the invention 4.

Figure 47 A, 47B, 47C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-1 and form successively in its surface.Figure 47 A, 47B, 47C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 48 A, 48B, 48C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the angle summary schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-2 and form successively in its surface.Figure 48 A, 48B, 48C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 49 A, 49B, 49C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-3 and form successively in its surface.Figure 49 A, 49B, 49C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 50 A, 50B, 50C lift the characteristic parameter that SAW (Surface Acoustic Wave) device is described and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-4 and form successively in its surface.Figure 50 A, 50B, 50C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 51 A, 51B, 51C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-5 and form successively in its surface.Figure 51 A, 51B, 51C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 52 A, 52B, 52C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-6 and form successively in its surface.Figure 52 A, 52B, 52C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 53 A, 53B, 53C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-7 and form successively in its surface.Figure 53 A, 53B, 53C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 54 A, 54B, 54C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-8 and form successively in its surface.Figure 54 A, 54B, 54C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 55 A, 55B, 55C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the simple schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-9 and form successively in its surface.Figure 55 A, 55B, 55C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 56 A, 56B, 56C illustrate the characteristic parameter of SAW (Surface Acoustic Wave) device and the angle summary schematic diagram of the normalized thickness h of ZnO film/λ variation relation, and SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-10 and form successively in its surface.Figure 56 A, 56B, 56C are respectively SAW (surface acoustic wave) velocity of wave, electromechanical coupling factor k ²And the change curve of TCV (temperature coefficient of SAW velocity of wave).

Figure 57 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).Reading SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-1 and form in its surface.

Figure 58 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-1 and form in its surface.

Figure 59 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the variation diagram of the TCV of SAW (Surface Acoustic Wave) device (temperature coefficient of SAW velocity of wave).This SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-10 and form in its surface.

Figure 60 illustrates, when the normalization thickness h/λ of ZnO film changes with the ψ value that limits the acoustic surface wave propagation direction, and the electromechanical coupling factor k of SAW (Surface Acoustic Wave) device ²Variation diagram.This SAW (Surface Acoustic Wave) device comprises: counter electrode films, ZnO film and the interdigital electrode utilizing the langasite monocrystalline matrix of area I V-10 and form in its surface.

Embodiment 1

In embodiment 1, the langasite monocrystalline is used as the matrix material of SAW device, and The matrix corner cut that representative cuts out from the langasite monocrystalline and surface acoustic wave are along the direction of propagation of matrix , θ and ψ then choose from overall area I. So just may realize reducing the SAW velocity of wave, improve Electromechanical coupling factor and reduction TCV (temperature coefficient of SAW velocity of wave). In embodiment 1, On the surface of langasite monocrystalline matrix, further cover the film that ZnO makes. Then, according to From matrix corner cut and the direction of propagation of surface acoustic wave on matrix that the langasite monocrystalline cuts out, control The thickness of piezoelectric film, realize thus the further raising of electromechanical coupling factor and/or TCV further Reduce. Can reduce so again the size of SAW device, improve passband width, and raising sound Temperature stability when surface wave device is used as wave filter. Especially may obtain, be suitable for most SAW filter with the mobile communication terminal device of intermediate frequency work.

There is preferred a pressure in overall area I inclusion region I-1 to I-10 in each zone The electrolemma thickness range. At regional I-1 and I-10, the absolute value of TCV can pass through piezoelectric film The selection of thickness reduces widely, can basically be down to zero in some situation. Just may obtain thus Get selective extraordinary SAW device.

As everyone knows, at LiNbO₃Or form on the piezoelectric base unit of similar compound by zinc oxide, The piezoelectric film of lithia, CdS (cadmium sulfide) or analogous components can improve SAW device Electromechanical coupling factor, typical in issuing among the JP-A 8-204499. But be so far End, also do not propose in the art to be included on the langasite monocrystalline matrix surface and form piezoelectric film SAW device. Now, the matrix corner cut harmony by selecting to cut out from the langasite monocrystalline The direction of propagation of surface wave on matrix, langasite matrix can obtain a positive TCV Value. On the other hand, the TCV value of ZnO film is born. When forming at the langasite matrix During ZnO film, the TCV value of the two will be cancelled each other, and total TCV value is just fallen widely Low. On this point, traditional piezoelectric base unit such as LiNbO₃Matrix is owing to have negative TCV Value, just improper, because when ZnO film is combined, total TCV value is just to negative direction Increase. By the specific langasite matrix among the embodiment 1 and the combination of zinc-oxide film, just can To realize the reduction of TCV, be to realize this reduction and utilize traditional matrix-film combination . Embodiment 2

In embodiment 2, in order to construct SAW device, on piezoelectric base unit, form successively and press Conductive film and interdigital electrode. The monocrystalline matrix is used as piezoelectric film as piezoelectric base unit, ZnO film. Logical Cross the formation piezoelectric film and can improve electromechanical coupling factor.

As everyone knows, form piezoelectric film on the piezoelectric base unit surface and can improve electromechanical coupling factor, allusion quotation Type such as among the JP-A 8-204499 announcement. Yet, as the LiNbO with negative value TCV₃When matrix was combined with ZnO film, total TCV value increased to negative direction.

In the present invention, the langasite monocrystal is as matrix material. By selecting from langasite The matrix corner cut that monocrystalline cuts out and the direction of propagation of surface acoustic wave on matrix, the langasite matrix can To obtain a positive TCV value. On the other hand, the TCV value of ZnO film is born. When When forming ZnO film on the langasite matrix, the TCV value of the two will be cancelled each other, and is total The TCV value will be reduced widely, therefore just can obtain a kind of utilize traditional piezoelectric base unit-Film is in conjunction with unavailable SAW device, and namely electromechanical coupling factor is enhanced, the TCV absolute value The SAW device that is lowered.

The interdigital electrode that JP-A 8-204499 also discloses on piezoelectric base unit forms piezoelectricity Film. And in embodiments of the invention 2, be the piezoelectric membrane of interdigital electrode on piezoelectric base unit Upper formation. In other words, what obtain in embodiment 2 is the uniform piezoelectric film of one deck, because piezoelectricity Film is that the smooth surface at piezoelectric base unit forms. So just can eliminate or reduce in a large number piezoelectricity The frequency fluctuation that the film irregularity causes.

There is one in overall area II inclusion region II-1 preferably to II-10 in each zone The piezoelectric film thickness range. At regional II-1 and II-10, the absolute value of TCV can be by pressing The selection of electrolemma thickness reduces widely, can basically be down to zero in some situation. Just can thus To obtain selective extraordinary SAW device.Embodiment 3

In embodiments of the invention 3, as shown in figure 31, piezoelectric film 4 is added to piezoelectric base unit 2 Upper with the structure SAW device. Piezoelectric base unit adopts langasite monocrystalline matrix, and piezoelectric film adopts ZnO film forms one deck counterelectrode film again on piezoelectric film. By forming piezoelectric film and anti-electricity Utmost point film just can improve the electromechanical coupling factor of device.

As everyone knows, form piezoelectric film on the piezoelectric base unit surface and can improve electromechanical coupling factor, allusion quotation Type as announcing among the JP-A 8-204499. Yet, as the LiNbO with negative value TCV₃And so on conventional matrix when ZnO film is combined, total TCV value increases to negative direction.

Everybody also knows, even when piezoelectric film is thinner, by adding one deck on the interdigital electrode opposite The counterelectrode film, and at it with separating with piezoelectric film, also can improve electromechanical coupling factor, typical case As Nikkan Kogyo Shinbun-Sha (1978) publish " Surface Wave Device, And Its Application " described in the pp.98-109. Yet traditional with counter electrode films SAW device in, usefulness be the matrix with piezoelectricity, such as glass, silicon or sapphire Matrix, rather than adopt piezoelectric base unit. One of reason may be traditional piezoelectric base unit-film knot Credit union causes that the TCV value is to the excessive increase of negative direction, as above-mentioned.

In embodiments of the invention 3, the langasite monocrystal is as matrix material. By selecting From matrix corner cut and the direction of propagation of surface acoustic wave on matrix that the langasite monocrystalline cuts out, Langasite monocrystalline matrix can obtain a positive TCV value. On the other hand, ZnO film The TCV value is born. When the langasite matrix forms ZnO film, the TCV value of the two Will cancel each other, total TCV value will be reduced widely. Therefore just can obtain a kind of profit With traditional piezoelectric base unit-film in conjunction with unavailable SAW device, i.e. electromechanical coupling factor Be enhanced the SAW device that the TCV absolute value is lowered.

In embodiments of the invention 3, the matrix corner cut harmony that representative cuts out from the langasite monocrystalline Surface wave is chosen from overall area III along , θ and the ψ of the propagation direction of matrix. So just may Realize reducing the SAW velocity of wave, improve electromechanical coupling factor and reduce the TCV (temperature of SAW velocity of wave The degree coefficient). Then, according to the matrix corner cut that cuts out from the langasite monocrystalline and surface acoustic wave at base The direction of propagation on the body, the thickness of control piezoelectric film is realized the further of electromechanical coupling factor thus The further reduction of raising and/or TCV. Can reduce so again the size of SAW device, carry Upper passband width, and the temperature stability when improving SAW device as wave filter. Especially can Surface acoustic wave filtering with the mobile communication terminal device that is suitable for most under intermediate frequency, working Device.

Overall area III inclusion region III-1 is to III-10, and is excellent in each one of zone existence The piezoelectric film thickness range of choosing. At regional III-1 and III-10, the absolute value of TCV can Selection by piezoelectric film thickness reduces widely, can basically be reduced to zero in some situation. Just can obtain thus selective extraordinary SAW device.Embodiment 4

In embodiments of the invention 4, as shown in figure 46, piezoelectric film 4 is added to piezoelectric base unit 2 Upper with the structure SAW device. Piezoelectric base unit adopts langasite monocrystalline matrix, and piezoelectric film adopts ZnO film, and between piezoelectric film and matrix, form one deck counter electrode films. By forming piezoelectricity Film and counter electrode films just can improve the electromechanical coupling factor of device.

As everyone knows, form piezoelectric film on the piezoelectric base unit surface and can improve electromechanical coupling factor, allusion quotation Type as announcing among the JP-A 8-204499. Yet, when traditional has negative value TCV's Piezoelectric base unit such as LiNbO₃Matrix, when ZnO film was combined, total TCV value was to negative direction Greatly increase.

Everybody also knows, even when piezoelectric film is thinner, by add interdigital electricity in counter electrode films The utmost point, and separating with piezoelectric film betwixt also can improve electromechanical coupling factor, typical as " Surface Wave Device, and that Nikkan kogyo Shinbun-sha (1978) publishes Its Application " pp98-109, described in. Yet at traditional sound with counter electrode films In the surface wave device, usefulness be the matrix with piezoelectricity, such as glass, silicon or sapphire substrates, Rather than piezoelectric base unit. One of reason may be that traditional piezoelectric base unit-film causes in conjunction with meeting The TCV value is to the excessive increase of negative direction.

The langasite monocrystal is as matrix material in embodiments of the invention 4. By select from The matrix corner cut that the langasite monocrystalline cuts out and the direction of propagation of surface acoustic wave on matrix, Langasite monocrystalline matrix can obtain a positive TCV value. On the other hand, ZnO film The TCV value is born. When the langasite matrix forms ZnO film, the TCV value of the two Will cancel each other, total TCV value will be amplified the earth and be reduced. Therefore just can obtain a kind of profit With traditional piezoelectric base unit-film in conjunction with unavailable SAW device, i.e. electromechanical coupling factor Be enhanced the SAW device that the TCV absolute value is lowered.

The interdigital electrode that JP-A8-204499 also discloses on piezoelectric base unit forms piezoelectricity Film. And in embodiments of the invention 4, counter electrode films and piezoelectric film form at piezoelectric base unit, Interdigital electrode forms at piezoelectric film. In other words, can obtain one deck in embodiment 4 presses uniformly Electrolemma forms because piezoelectric film is smooth surface in counter electrode films. So just can eliminate Or reduce in a large number the frequency fluctuation that the piezoelectric film irregularity causes.

In embodiments of the invention 4, the matrix corner cut harmony that representative cuts out from the langasite monocrystalline Surface wave is chosen from overall area IV along , θ and the ψ of the direction of propagation of matrix. So just may Realize reducing the SAW velocity of wave, improve electromechanical coupling factor and reduce the TCV (temperature of SAW velocity of wave The degree coefficient). Then according to the matrix corner cut that cuts out from the langasite monocrystalline and surface acoustic wave at matrix On the direction of propagation, control piezoelectric film thickness, realize thus further carrying of electromechanical coupling factor The further reduction of height and/or TCV. So just can reduce the size of surface device, improve logical Bandwidth, and the temperature stability when improving SAW device as wave filter. Especially may Obtain, be suitable for the SAW filter with the mobile communication terminal device of intermediate frequency work most.

Overall area IV inclusion region IV-1 exists in each zone-individual preferred to IV-10 The piezoelectric film thickness range. At regional IV-1 and IV-10, the absolute value of TCV can lead to The selection of crossing piezoelectric film thickness reduces widely, can basically be down to zero in some situation. Thus Just may obtain selective extraordinary SAW device.

Should be understood that at this, for example at " NUMERICAL AND EXPERIMENTAL INVESTIGATION SAW IN LANGASITE (numerical value of surface acoustic wave and experimental study among the LANGASITE) ", 1995 IEEE ULTRASONICS SYMPOSIUM, Vol.1, in 389 (lists of references 1), provided the Eulerian angles (( of the direction of propagation on matrix when the matrix corner cut that cuts out from the langasite monocrystalline and surface acoustic wave, θ, when ψ) representing, under following situations, the SAW velocity of wave of langasite monocrystalline matrix, k²/ 2 and the numerical result of TCD (temperature coefficient in SAW delay time) etc.:

(0°，30°，90°)

(0°，53°，90°)

(0°，61°，0°)

(0°，147°，22°)

(0°，147 °，18 °)

(0°，32°，40°)

(0°，156°，0°)

(0°，θ，0°)

(0 °, 25 °, ψ) in addition, at " Effect of Electric Field and of Mechanical Pressure on Surface Acoustic Waves Propagation in La₃Ga ₅SiO ₁₄Piezoelectric Single Crystals " 1995 IEEE ULTRASONICS SYMPOSIUM; Vol.1, in 409 (lists of references 2), when also having provided matrix and having represented with Eulerian angles; under following situations, k²Deng numerical result:

(0°，90°，ψ)

(0°，0°，ψ)

(0°，θ，0°)

(90°，θ，0°)

(φ, 90 °, 0 °) and, provided matrix Eulerian angles (φ in the paper " A Study on SAW propagation characteristics on a langasite crystal plate " in " The 17th Symposium Preprint on the Fundamentals and Applications of Ultrasionic Electronics " (list of references 3), θ, when ψ) representing, namely at (90 °, 90 °, k in the time of ψ)², the calculated value of TCD etc. and matrix under following situations, the measured value of TCD:

(0°，0°，90°)

(90°，90°，175°)

(90 °, 90 °, 25 °) and, in Japanese Academy for the Advancement of Science, the material that distributes in the 51st seminar of the 150th the surface acoustic wave techniques committee, in the 21st page of paper " Propagation direction dependence of Rayleigh Waves on a langastie plate ", when also having provided matrix with Eulerian angles (φ, θ, ψ) expression, under following situations, k²Deng numerical result:

(0°，0°，4)

(90 °, 90 °, 4) and the matrix TCD result that the serial resonant frequency of usefulness actual measurement is calculated under following situations:

(0°，0°，90°)

(90°，90°，175°)

(90°，90°，15°)

(90°，90°，21°)

(90 °, 90 °, 25 °) The date issued of list of references 4 is on January 27th, 1997, namely carries in the application of the application's basis After the friendship. Also have, at " The 17th Symposium Preprint on the Fundamentals And Applications of Ultrasonic Electronics " in paper " Propagation Characteristics of surface acoustic waves on La₃Ga ₅SiO ₁₄" in also provided matrix, with Eulerian angles (φ, θ, ψ) when expression k under following situations²Deng numerical result:

(90°，90°，ψ)

(0°，0°，ψ)

(0°，θ，0°)

Above-mentioned all lists of references all relate to the performance of langasite monocrystalline matrix self, yet it All do not disclose at langasite monocrystalline matrix and added the ZnO piezoelectric film. In the present invention, logical Cross the matrix corner cut and the propagation side of surface acoustic wave on matrix that control from the langasite monocrystalline cuts out To, obtain optimum piezoelectric film thickness, with the further raising that realizes electromechanical coupling factor and/or The further reduction of TCV. Therefore, the present invention can predict easily by above-mentioned list of references Arrive.Embodiment 1

According to a kind of typical construction of the SAW device of the embodiment of the invention 1 as shown in Figure 1. This SAW device comprises: matrix 2, the interdigital electricity of a cover input that forms on matrix 2 surfaces The piezoelectric film 4 of the utmost point 3 and output interdigital electrode 3 and covering matrix 2 and interdigital electrode 3. At this Among each embodiment of invention, all use the langasite monocrystal to make matrix 2, the langasite monocrystalline Body belongs to point group 32. In each embodiment of the present invention, all make piezoelectric film 4 with ZnO, The piezoelectric axis of piezoelectric film basically with the Surface Vertical of matrix.

Among Fig. 1, x, y, z axle are orthogonal. X, y axle are positioned at the in-plane of matrix 2 On, the direction of propagation of x axle definition surface acoustic wave. The z axle is perpendicular to the matrix plane, and definition is from monocrystalline In the corner cut (section) of the matrix that cuts out. These x, y, z axle and langasite monocrystalline The available Eulerian angles of the relation of X, Y, Z axis (φ, θ, ψ) expression.

In the SAW device according to embodiment 1, when the matrix that cuts out from the langasite monocrystalline When the direction of propagation of corner cut and surface acoustic wave represents with (φ, θ, ψ), φ, θ, ψ is positioned at In the regional that face is mentioned.

By from overall area I, selecting φ, θ, ψ and form the piezoelectric film of suitable thickness can be real Now reduce the SAW velocity of wave, improve electromechanical coupling factor and reduce TCV. Thereby reduce surface acoustic wave The size of device improves passband width, and the temperature when improving SAW device as wave filter Stability. Especially, may be suitable for mobile communication terminal device with intermediate frequency work most SAW filter. More specifically, the TCV of matrix or SAW velocity of wave temperature coefficient can Be-35～60ppm/ ℃, the SAW velocity of wave can be up to 2900m/s, and electromechanical coupling factor can be 0.1% or higher. In some cases, can also obtain better performance.

At regional I-1, I-6, I-7, I-8, I-9 and I-10, because The coefficient of coup can reach 0.4% or higher, can obtain having the more SAW device of broad passband. At regional I-1, I-7 and I-10, the coefficient of coup reach 0.7% or higher, the sound table that obtains The passband of ground roll device is wider than above-mentioned situation.

At regional I-1 and I-10, TCV can be reduced widely, in some situation very Zero to being down to, thus the SAW device that obtains just has enough good temperature stability. Especially at regional I-1 since can obtain by the selection of piezoelectric film thickness the big coefficient of coup and Little TCV just can obtain having broad passband and enough surface acoustic wave devices of good temperature stability Part.

Should be understood that it is that the initial temperature coefficient is used as TCV here, i.e. the temperature of SAW velocity of wave system Number. Even temperature-sound velocity curve is secondary (initial temperature coefficient be zero), also use young waiter in a wineshop or an inn Multiplication can be approximated to initial straight to conic section, in order to calculate TCV. Particularly, the unit's of using temperature The SAW velocity of wave V of the SAW velocity of wave changes delta V of degree section during divided by 0 ℃₀Can obtain TCV.

Tangentially can determining with X-ray diffraction method of matrix.

Langasite monocrystal among the present invention is used chemical molecular formula La usually₃Ga ₅SiO ₁₄Expression, At PROC.IEEE International Freqnency Control Sympo.Vol.1994, Propose as example among the pp48-57 (1994) and by known to the people. In the present invention, The langasite monocrystal is used as the matrix of SAW device. In this case, if crystal The direction of propagation tangential and surface acoustic wave selected especially, just can obtain having as mentioned above High performance SAW device. If find the langasite monocrystal by X-ray diffraction method The somewhere is main only by the langasite phase composition, just can use herein. In other words, use herein The langasite monocrystal may not non-ly be confined to the composition of above-mentioned chemical molecular formula, for example, at least one Part La, the lattice position of Ga and Si can be by other element substitution, and the number of oxygen also can depart from The molecular formula of above-mentioned stoichiometric(al). And, may contain in the langasite monocrystal inevitably Impurity such as Al, Zr, Fe, Ce, Nd, Pt and Ca. For how making langasite Monocrystal does not have special restriction yet, that is to say, can be with common monocrystalline growing process manufacturing, Such as CZ technology.

In embodiment 1, can be according to the preferred piezoelectricity thickness of the location positioning of (φ, θ, ψ) Degree. More specifically, as previously mentioned, there is preferred h/ λ in each zone. Wherein h presses The thickness of electrolemma, λ are the wavelength of surface acoustic wave, and h/ λ is with the pressure behind the surface acoustic wave wavelength normalization Electrolemma thickness. In general, in overall area I from regional I-2 to I-9, the h/ λ value is more Greatly, electromechanical coupling factor and SAW velocity of wave are just more big. And at regional I-1 and I-10, h/ λ Be worth more greatly, the SAW velocity of wave is just more little. Therefore, it is enough to select in each zone electromechanical coupling factor Greatly, the enough little scope of SAW velocity of wave. Along with h/ λ increases, has the TCV of the matrix of piezoelectric film Or SAW velocity of wave temperature coefficient just increases to negative direction. Therefore, has positive TCV when matrix self During value, add piezoelectric film after the TCV value may descend.

In each embodiment of the present invention, there is not special limit for how forming piezoelectric film System that is to say, piezoelectric film can generate with the technology of any needs, as long as the piezoelectric film that generates Piezoelectric axis and matrix plane perpendicular just can. These technologies for example comprise sputtering technology, Ion film plating technology, CVD (chemical vapour deposition (CVD)) technology etc. If it is suitable to choose in advance The film formation condition, by these technologies just can easily obtain piezoelectric axis or C-axle basic with The piezoelectric film that matrix surface is perpendicular.

In each embodiment of the present invention, the matrix dimensional requirement is not strict, passes along surface acoustic wave Broadcasting direction is about 1～20mm, is about 0.5～5mm perpendicular to the direction of propagation. Matrix Thickness is the finger spacing (ripple that is equivalent to surface acoustic wave of the interdigital electrode that forms at matrix at least Long) three times, be generally about 0.2～0.5mm. Yet should be pointed out that in some feelings Under the condition, for the test specimen for estimating that substrate performance is prepared, its thickness can exceed the above-mentioned upper limit 0.5mm. For example, in order to test, the finger spacing of interdigital electrode is 320 μ m, and then matrix is thick Degree is at least 0.96mm.

In the present invention, each interdigital electrode that forms at matrix 2 is periodic strip Membrane electrode is used for exciting, receives, reflects and propagates surface acoustic wave. Interdigital electrode is by certain side It is in order to realize that surface acoustic wave propagates by the above-mentioned predetermined direction of propagation that formula is arranged. Interdigital electrode is with Au or Al, by the method formation of evaporation or sputter. The finger width of interdigital electrode can be according to application The frequency of SAW device determines, and at the frequency band range of advantageous applications of the present invention, finger is wide Degree is usually about 2～10 μ m. The thickness of interdigital electrode is generally 0.03～1.5 μ m.

According to various embodiments of the present invention, in general SAW device be highly suitable for 10～The wave filter of working under the 500MHz frequency band is particularly useful for 10～300MHz. Sound of the present invention Surface wave device because the SAW velocity of wave is low, also helps the chi that reduces the saw delay element Very little.Embodiment 2

A kind of typical structure such as Figure 16 institute according to the SAW device of the embodiment of the invention 2 Show. This SAW device comprises: matrix 2, the piezoelectric film 4 that forms on matrix 2 surfaces, With cover input interdigital electrode 3 and an output interdigital electrode 3 that forms on piezoelectric film 4 surfaces.

In the SAW device according to embodiment 2, when the matrix that cuts out from the langasite monocrystalline When the direction of propagation of corner cut and surface acoustic wave represents with (φ, θ, ψ), φ, θ, ψ is positioned at In the regional that face is mentioned.

By from overall area II, selecting φ, θ, ψ and form the piezoelectric film of suitable thickness can To realize the reducing SAW velocity of wave, improve electromechanical coupling factor and to reduce TCV. Thereby reduce the sound table The size of ground roll device improves passband width, and when improving SAW device as wave filter Temperature stability. Especially, may be suitable for mobile communication terminal with intermediate frequency work most The SAW filter of equipment. More specifically, the TCV of matrix or SAW velocity of wave temperature coefficient Can be-35～60ppm/ ℃, the SAW velocity of wave can be stated 2900m/s by height, and electromechanical coupling factor can Reach 0.1% or higher. In some cases, can also obtain better performance.

At overall area II, because the coefficient of coup that obtains can be up to 0.4% or higher, so can To obtain the wideband acoustic surface-wave device. And at regional II-1 and II-10, because the coefficient of coup Up to 0.8% or higher, so can obtain the more SAW device of broad passband.

At regional II-1 and II-10, because TCV can be reduced widely, obtain SAW device can have enough good temperature stability. And at regional II-1 and II-10, owing to can obtain the big coefficient of coup and little TCV by selection piezoelectric film thickness, so The SAW device that obtains just can have much wide passband and much better temperature stability.

In embodiment 2, can be according to the preferred piezoelectricity thickness of the location positioning of (φ, θ, ψ) Degree. More specifically, there is preferred h/ λ in each zone. Wherein h is the thickness of piezoelectric film, λ is the wavelength of surface acoustic wave, and h/ λ is with the piezoelectric film thickness behind the surface acoustic wave wavelength normalization. One As, in overall area II from regional II-2 to II-9, the h/ λ value is more big, dynamo-electric coupling Syzygy number and SAW velocity of wave are just more big. And at regional II-1 and II-10, the h/ λ value is more big, The SAW velocity of wave is just more little. Along with h/ λ increases, has the temperature of SAW velocity of wave of the matrix of piezoelectric film Degree coefficient or TCV increase to negative direction. Therefore, when matrix self has positive TCV value, The TCV value may descend after adding piezoelectric film.

Therefore should preferentially choose such h/ λ value in each zone: it can improve necessity greatly Performance, or SAW velocity of wave, the performance of electromechanical coupling factor and TCV. As previously mentioned, whenever All there is a specific h/ λ scope in individual zone, can really satisfy these performance requirements.Embodiment 3

A kind of typical structure such as Figure 31 institute according to the SAW device of the embodiment of the invention 3 Show. This SAW device comprises: matrix 2, to be added in the lip-deep cover input of matrix 2 interdigital The piezoelectric film 4 of electrode 3 and output interdigital electrode 3 and covering matrix 2 and

interdigital electrode

3 and 3. And, on the surface of piezoelectric film 4, also formed one deck counter electrode films 5.

In the SAW device according to embodiment 3, when the matrix that cuts out from the langasite monocrystalline When the direction of propagation of corner cut and surface acoustic wave represents with (φ, θ, ψ), φ, θ, ψ is positioned at In the regional that face is mentioned.

By from overall area II, selecting φ, θ, the piezoelectric film of ψ and formation suitable thickness and anti-Electrode film can be realized reducing the SAW velocity of wave, improves electromechanical coupling factor and reduce the SAW velocity of wave Temperature coefficient or TCV. Thereby reduce the size of SAW device, improve passband width, and carry Temperature stability when high SAW device is used as wave filter. Especially, may obtain the most suitable Be used for the SAW filter with the mobile communication terminal device of intermediate frequency work. More specifically, base SAW velocity of wave temperature coefficient or the TCV of body can be-35～60ppm/ ℃, and the SAW velocity of wave Can be up to 2900m/s, electromechanical coupling factor can reach 0.1% or higher, in some cases, also can To obtain much better performance.

At overall area III, with respect to piezoelectric film thickness, electromechanical coupling factor has two peak values. Right Should be in the peak value of thin piezoelectric film side, be enough big value in the practicality, 0.13% or bigger. Especially at regional III-4, the peak value of its coefficient of coup is 0.37%. With respect to thick piezoelectric film side A peak value is also arranged, and also is enough big value in the practicality, 0.15% or bigger. At this moment, with do not have Piezoelectric film is compared, and TCV approximately improves 20ppm/ ℃.

In embodiment 3, can be according to the preferred piezoelectricity thickness of the location positioning of (φ, θ, ψ) Degree. More specifically, as previously mentioned, there is preferred h/ λ for each zone. Wherein h is The thickness of piezoelectric film, λ are the wavelength of surface acoustic wave, and h/ λ is with behind the wavelength normalization of surface acoustic wave Piezoelectric film thickness. The h/ λ value is more big, and at regional III-1 and III-10, the SAW velocity of wave just More little, and at regional III-2 to III-9, the SAW velocity of wave is then more big. As previously mentioned, exist Overall area III, with respect to h/ λ, electromechanical coupling factor has two peak values. When the electromechanical coupling factor place When the peak value of big h/ λ side, the absolute value of TCV just diminishes. Along with h/ λ increases, with piezoelectricity The SAW velocity of wave temperature coefficient of the matrix of film or TCV value increase to negative direction. Therefore work as matrix The TCV value of self is timing, add piezoelectric film after the TCV value may descend.

Therefore should preferentially choose such h/ λ value in each zone: it can improve necessity greatly Performance, or the performance of SAW velocity of wave, electromechanical coupling factor and TCV. As previously mentioned, whenever All there is a specific h/ λ scope in individual zone, can really satisfy these performance requirements.

The size of counter electrode films 5 may cover whole piezoelectric film 4. Yet, with regard to present embodiment and Speech in a zone relative with the interdigital electrode of input and output side, should generate counterelectrode at least Film. The preferred thickness range of counter electrode films is 0.03～0.1 μ m, and is too thin improper, because The film that arrives may be discontinuous, and the electromotive force on the thin film planar can become owing to the increase of resistance Inhomogeneous. Too thick also improper, because can cause the increase of counter electrode films gross weight. Counterelectrode The material of film can be identical with the interdigital electrode of narrating above with the formation method. Counter electrode films may not be always Ground connection, or always be in coupled situation, it can be in electric insulating state.Embodiment 4

A kind of typical structure such as Figure 46 institute according to the SAW device of the embodiment of the invention 4 Show. This SAW device comprises: matrix 2, be added in matrix 2 lip-deep counter electrode films 5, Be added in the piezoelectric film 4 on the counter electrode films 5 and be added in piezoelectric film 4 lip-deep cover inputs interdigital Electrode 3 and output interdigital electrode 3.

In the SAW device according to embodiment 4, when the matrix that cuts out from the langasite monocrystalline When the direction of propagation of corner cut and surface acoustic wave represents with (φ, θ, ψ), φ, θ, ψ is positioned at In the regional that face is mentioned.

By from overall area IV, selecting φ, θ, the piezoelectric film of ψ and formation suitable thickness and anti-Electrode film can be realized reducing the SAW velocity of wave, improves electromechanical coupling factor and reduce TCV. From And reduce the size of SAW device, improve passband width, and improve the surface acoustic wave device as filter Temperature stability during the ripple device. Especially, may be suitable for movement with intermediate frequency work most The SAW filter of communication terminal device. More specifically, the SAW velocity of wave temperature coefficient of matrix Or TCV can be-35～60ppm/ ℃ that the SAW velocity of wave can be up to 2900m/s, dynamo-electric coupling The syzygy number can reach 0.1% or higher, in some cases, can also obtain better performance.

At overall area IV, because the coefficient of coup that obtains can be up to 0.2% or higher, so can To obtain the wideband acoustic surface-wave device. Especially at regional IV-1 and IV-10, because coupled systemes Number is up to 0.8% or higher, so can obtain the SAW device of much wide passband.

At regional IV-1 and IV-10, owing to TCV can be reduced widely, sometimes very To being down to zero, the SAW device that obtains can have enough good temperature stability. And At regional II-1 and II-10, because by selecting piezoelectric film thickness can obtain big coupling Coefficient and little TCV, thus the SAW device that obtains just can have much wide passband and Much better temperature stability.

Mention, in embodiment 4, can be preferred according to the location positioning of (φ, θ, ψ) Piezoelectric film thickness. More specifically, there is preferred h/ λ in each zone. Wherein h presses The thickness of electrolemma, λ are the wavelength of surface acoustic wave, and h/ λ is with the pressure behind the surface acoustic wave wavelength normalization Electrolemma thickness. In general, in overall area IV from regional IV-2 to IV-9, the h/ λ value More big. Electromechanical coupling factor and SAW velocity of wave are just more big. And at regional IV-1 and IV-10, Then the h/ λ value is more big, and the SAW velocity of wave is just more little. Along with h/ λ increases, has the matrix of piezoelectric film SAW velocity of wave temperature coefficient or TCV increase to negative direction. Therefore, have positive when matrix self During the TCV value, add piezoelectric film after the TCV value may descend.

With regard to present embodiment, counter electrode films 5 at least should with the interdigital electrode of input and output side Form on the relative zone. But, in order to make piezoelectric film 4 even, counter electrode films 5 is covered Cover whole matrix 2. The preferred thickness range of counter electrode films is 0.03～0.1 μ m. Not too thin not conforming to Suitable, because the film that obtains may be discontinuous, and the electromotive force on the thin film planar can be because resistance Increase and become inhomogeneous. Too thick also improper, because the increase of the electrode film gross weight of can rising in rebellion. The material of counter electrode films can be identical with the interdigital electrode of narrating above with the formation method. Counter electrode films is not Ground connection always, or always be in coupled situation, it can be in electric insulating state.

Below in conjunction with instance interpretation the present invention.Example I-1 (embodiment 1)

With CZ technology growth langasite monocrystal, cutting langasite monocrystal obtains matrix. Form SAW transducer at matrix surface, this SAW transducer comprises a cover input fork Refer to electrode and output interdigital electrode, and on transducer, generate ZnO film with magnetron sputtering technique, To make SAW device. Interdigital electrode all is identical shaped ordinary electrode, gives birth to the Al evaporation Become, its thickness is 0.1 μ m, and electrode finger width d is 15 μ m, electrode finger spacing (4d) Be 60 μ m (wavelength that are equivalent to surface acoustic wave), the right number of electrode finger is 40, and electrode refers to Between bar aperture be 60 λ (=3.6mm). Yet, when weak output signals, above-mentioned fork Aperture becomes 100 λ between the finger of finger electrode, and other is constant. In addition, work as ZnO film Normalization thickness surpass at 0.4 o'clock, electrode finger width reduces by half to 30 μ m, aperture is also corresponding Reduce by half to 1.8mm (=60 λ).

In this example, the corner cut that cuts out from the langasite monocrystal when matrix and surface acoustic wave are at base When the direction of propagating on the body represented with Eulerian angles (φ, θ, ψ), φ, θ were respectively 0 ° and 90 °. ψ is used for determining the direction of propagation of X-axis and surface acoustic wave, the ψ value of selecting from overall area I Shown in Fig. 2 A～10C. The selection of the thickness h of the ZnO film on the matrix should be satisfied above-mentioned Normalization thickness h/λ=0.05～0.8. On each direction of propagation, measured the SAW velocity of wave, Electromechanical coupling factor k², and the variable quantity of SAW velocity of wave temperature coefficient TCV when h/ λ changes. The SAW velocity of wave is obtained by the centre frequency of wave filter, and electromechanical coupling factor k²Then utilize famous The Smith equivalent-circuit model. With the two ends admittance (admittanee) of measuring SAW transducer Obtain. SAW velocity of wave on each direction, k²Be marked on Fig. 2 A～10C with the measurement result of TCV On.

In each figure, do not mark result's each point, do not detect the surface acoustic wave signal. Consider and measure The result of electromechanical coupling factor, a possible reason is when this scope is propagated, dynamo-electric coupling The syzygy number is too little, can not effectively change into the surface acoustic wave signal to the signal of telecommunication, and vice versa. When When the normalization thickness h of ZnO film/λ increased, the wave mode of surface acoustic wave had just disappeared. Occurred Bulk wave. Therefore, the data that obtain after the bulk wave generation all do not mark.

SAW velocity of wave and k²Change curve show, if the corner cut harmony that matrix cuts out from crystal The surface direction of wave travel drops on overall area I, and then the SAW velocity of wave can drop to 2900m/s or lower. Compare with traditional ST quartz crystal, this more is conducive to reduce the size of SAW device. Also send out The electromechanical coupling factor that present overall area I obtains can be 0.1% or higher. So just may pass through The selection of ZnO film thickness obtains much higher electromechanical coupling factor.

Continue to consider the variation diagram of TCV, when the TCV of matrix self be on the occasion of the time, in other words, When the TCV of matrix during at normalization thickness h/λ=0 be on the occasion of the time, find along with h/ λ increases, The TCV value is from the occasion of changing to the negative value direction, thereby improved temperature performance, on the other hand, works as base When body has negative value TCV, add ZnO film, and when increasing normalization thickness, the TCV value Just increase widely to negative direction. Even in this case, the absolute value of TCV is also not very too big (approximately 35ppm/ ℃ or lower); If also find to adopt BGO matrix commonly used, matrix then How temperature stability is so great that and improves.

Below, detailed explanation is carried out in each zone:

Can be found out by Fig. 2 B, 2C, utilize the device of regional I-1, when h/ λ=0.6, Its electromechanical coupling factor can up to 0.76%, at this moment, TCV=-26ppm/ ℃, have enough Good temperature performance.

Can be found out by Fig. 3 B, 3C, utilize the device of regional I-2, when h/ λ=0.5, Its electromechanical coupling factor can state 0.32% by height, and at this moment, TCV=9ppm/ ℃, it is enough good to have Temperature performance.

By Fig. 4 B, 4C can find out, utilizes the device of regional I-3, when h/ λ=0.4, Its electromechanical coupling factor can be up to 0.15%, and at this moment, TCV=32ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Fig. 5 B, 5C, utilize the device of regional I-4, when h/ λ=0.4, Its electromechanical coupling factor can be up to 0.19%, and at this moment, TCV=17ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Fig. 6 B, 6C, utilize the device of regional I-5, when h/ λ=0.35, Its electromechanical coupling factor can be up to 0.25%, and at this moment, TCV=16ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Fig. 7 B, 7C, utilize the device of regional I-6, when h/ λ=0.35, Its electromechanical coupling factor can be up to 0.61%, and at this moment, TCV=17ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Fig. 8 B, 8C, utilize the device of regional I-7, when h/ λ=0.35, Its electromechanical coupling factor can be up to 0.72%, and at this moment, TCV=19ppm/ ℃, it is enough good to have Temperature performance.

By Fig. 9 B, 9C can find out, utilizes the device of regional I-8, when h/ λ=0.35, Its electromechanical coupling factor can be up to 0.53%, and at this moment, TCV=33ppm/ ℃, it is enough good to have Warm reflexive energy.

Can be found out by Figure 10 B, 10C, utilize the device of regional I-9, when h/ λ=0.5, Its electromechanical coupling factor can be up to 0.63%, and at this moment, TCV=12ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Figure 11 B, 11C, utilize the device of regional I-10, when h/ λ=0.55 The time, its electromechanical coupling factor can up to 0.96%, at this moment, TCV=24ppm/ ℃, have foot Enough good temperature performances. Example 1-2 (embodiment 1)

Press the SAW device that example 1-1 makes, different from 1-1 is: φ and θ are respectively Be 0 ° and 90 °, and be used for determining that the ψ value of X-axis or acoustic surface wave propagation direction is from-80 ° To-66 °, select a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is at regional I In-1. Measured TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 12. Also measured k²The relation of-h/ λ the results are shown in Figure 13.

On the one hand, as can be seen from Figure 12, at regional I-1, can obtain so-called zero-temperature coefficient Can, and become corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave Change. On the other hand, as can be seen from Figure 13, when the ZnO film thickening, electromechanical coupling factor Be tending towards becoming big. Therefore, if select ZnO film thickness in order to obtain the zero-temperature coefficient performance, simultaneously The selected direction of propagation so just can obtain to have in order to obtain enough big electromechanical coupling factor The SAW device of zero-temperature coefficient performance and big electromechanical coupling factor. For example, if direction of propagation ψ Be-70 °, normalization thickness h/λ of ZnO is 0.35, and then at this moment TCV can be down to basically Zero, and k²Can be up to 0.32%, so just can obtain to have little size, wide passband and non-The SAW device of normal good temperature performance. Example 1-3 (embodiment 1)

Press the SAW device that example 1-1 makes, different from 1-1 is: φ and θ are respectively Be 0 ° and 90 °, and the ψ value that is used for determining X-axis or acoustic surface wave propagation direction from 66 ° to 80 ° are selected a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is in regional I-10. Measure TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 14. Also Measured k²The relation of-h/ λ the results are shown in Figure 15.

On the one hand, as can be seen from Figure 14, at regional I-10, can obtain the zero-temperature coefficient performance, And change corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave. On the other hand, as can be seen from Figure 15, when the ZnO film thickening, electromechanical coupling factor is more than change Greatly. Therefore, if in order to obtain enough big electromechanical coupling factor selected ZnO film thickness, The selected direction of propagation in order to obtain the zero-temperature coefficient performance so just can obtain to have zero-temperature coefficient simultaneously The SAW device of performance and big electromechanical coupling factor. For example, if direction of propagation ψ is 70 °, normalization thickness h/λ of ZnO is 0.35, then at this moment TCV can be down to zero basically, and k²Can be up to 0.6%, so just can obtain to have little size, wide passband and extraordinary temperature The SAW device of degree performance.Example 2-1 (embodiment 2)

With CZ technology growth langasite monocrystal, from the thick base of monocrystal cutting 0.35mm Body. On matrix surface, generate ZnO film with magnetron sputtering technique, generate at ZnO film SAW transducer, to make SAW device, this SAW transducer comprises: a cover Input interdigital electrode and output interdigital electrode. Interdigital electrode all is identical shaped ordinary electrode, uses Al evaporates generation, and its thickness is 0.1 μ m, and electrode finger width d is 15 μ m, between the electrode finger Distance (4d) is 60 μ m (wavelength that are equivalent to surface acoustic wave), and the right number of electrode finger is 40, Between finger aperture be 60 λ (=3.6mm). Yet, when weak output signals, above-mentioned Aperture becomes 100 λ between the finger of interdigital electrode, and other is constant. In addition, when ZnO thin The normalized thickness of film surpasses at 0.4 o'clock, and electrode finger spacing reduces by half to 30 μ m, and aperture also Corresponding reducing by half to 1.8mm (=60 λ).

In this example, the corner cut that cuts out from the langasite monocrystal when matrix and surface acoustic wave are at base When the direction of propagation on the body represented with Eulerian angles (φ, θ, ψ), φ and θ were respectively 0 ° and 90 °. ψ is used for determining the direction of propagation of X-axis and surface acoustic wave, the ψ value of selecting from overall area II Shown in Figure 17 A～26C. The selection of the thickness h of the ZnO film on the matrix is on should satisfying State normalization thickness h/λ=0.05～0.8. For relatively, prepared h/ λ=0, namely do not have The SAW device of ZnO film. On each direction of propagation, SAW velocity of wave, machine have been measured Electric coupling coefficient k², and the SAW velocity of wave obtain electromechanical coupling factor k by the centre frequency of wave filter²Utilize famous Smith equivalent-circuit model, with the two ends admittance of measuring SAW transducer Obtain. SAW velocity of wave, k on each direction²Be marked on Figure 17 A～26C with the measurement result of TCV On.

Along with the normalization thickness h of ZnO film/λ increases, the wave mode of surface acoustic wave disappears, and goes out Existing bulk wave. Therefore, the data that obtain after the bulk wave generation all do not mark.

SAW velocity of wave and k²Change curve show, if the corner cut harmony that matrix cuts out from crystal The surface direction of wave travel drops on overall area II, and then the SAW velocity of wave can drop to 2900m/s or lower. Compare with traditional ST quartz crystal, this more is conducive to reduce the size of SAW device. Also send out The electromechanical coupling factor that present overall area I obtains can be 0.1% or higher. So just may pass through The selection of ZnO film thickness obtains much higher electromechanical coupling factor.

Below, detailed explanation is carried out in each zone.

Can be found out by Figure 17 B, 17C, utilize the device of regional II-1, when h/ λ=0.8, Its electromechanical coupling factor can up to 0.88%, at this moment, TCV=-30ppm/ ℃, have enough Good temperature performance.

Can be found out by Figure 18 B, 18C, utilize the device of regional II-2, when h/ λ=0.55 The time, its electromechanical coupling factor can up to 0.6%, at this moment, TCV=9ppm/ ℃, have enough Good temperature performance.

By Figure 19 B, 19C can find out, utilizes the device of regional II-3, when h/ λ=0.35 The time, its electromechanical coupling factor can up to 0.44%, at this moment, TCV=29ppm/ ℃, have foot Enough good temperature performances.

Can be found out by Figure 20 B, 20C, utilize the device of regional II-4, when h/ λ=0.4, Its electromechanical coupling factor can be up to 0.56%, and here, TCV=17ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Figure 21 B, 21C, utilize the device of regional II-5, when h/ λ=0.35 The time, its electromechanical coupling factor can up to 0.53%,, TCV=15ppm/ ℃, have foot here Enough good temperature performances.

Can be found out by Figure 22 B, 22C, utilize the device of regional II-6, when h/ λ=0.3, Its electromechanical coupling factor can be up to 0.59%, and at this moment, TCV=16ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Figure 23 B, 23C, utilize the device of regional II-7, when h/ λ=0.35 The time, its electromechanical coupling factor can up to 0.63%, at this moment, TCV=19ppm/ ℃, have foot Enough good temperature performances.

By Figure 24 B, 24C can find out, utilizes the device of regional II-8, when h/ λ=0.3, Its electromechanical coupling factor can be up to 0.51%, and at this moment, TCV=32ppm/ ℃, it is enough good to have Temperature performance.

Can be found out by Figure 25 B, 25C, utilize the device of regional II-9, when h/ λ=0.55 The time, its electromechanical coupling factor can up to 0.59%,, TCV=11ppm/ ℃, have foot here Enough good temperature performances.

Can be found out by Figure 26 B, 26C, utilize the device of regional II-10, when h/ λ=0.75 The time, its electromechanical coupling factor can up to 0.86%, here, TCV=-30ppm/ ℃, have Enough good temperature performances.

Example 2-2 (embodiment 2)

Press the SAW device that example 1-1 makes, different from 2-1 is: φ and θ are respectively Be 0 ° and 90 °, and be used for determining that the ψ value of X-axis or acoustic surface wave propagation direction is from-80 ° To-66 °, select a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is at regional II In-2. Measured TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 27. Also measured k²The relation of-h/ λ the results are shown in Figure 28.

On the one hand, as can be seen from Figure 27, at regional II-1, can obtain the zero-temperature coefficient performance, And change corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave. On the other hand, as can be seen from Figure 13, when the ZnO film thickening, electromechanical coupling factor is tending towards Become big. Therefore, if in order to obtain the zero-temperature coefficient performance selected ZnO film thickness, simultaneously for Obtain enough big electromechanical coupling factor and the selected direction of propagation, so just can obtain to have zero temperature The SAW device of degree performance and big electromechanical coupling factor. For example, if direction of propagation ψ be-70 °, normalization thickness h/λ of ZnO is 0.35, and then at this moment TCV can be down to zero basically, And k²Can be up to 0.51%, so just can obtain to have little size, wide passband and very good The SAW device of temperature performance. Example 2-3 (embodiment 1)

Press the SAW device that example 2-1 makes, different from 2-1 is: φ and θ are respectively Be 0 ° and 90 °, and the ψ value that is used for determining X-axis or acoustic surface wave propagation direction from 66 ° to 80 ° are selected a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is in regional II-10. Measure TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 29. Also Measured k²The relation of-h/ λ the results are shown in Figure 30.

On the one hand, as can be seen from Figure 29, at regional II-10, can obtain the zero-temperature coefficient performance, And change corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave. On the other hand, as can be seen from Figure 30, when the ZnO film thickening, electromechanical coupling factor is more than change Greatly. Therefore, if in order to obtain enough big electromechanical coupling factor selected ZnO film thickness, The selected direction of propagation in order to obtain the zero-temperature coefficient performance so just can obtain to have zero-temperature coefficient simultaneously The SAW device of performance and big electromechanical coupling factor. For example, if the direction of propagation 4 is 70 °, normalization thickness h/λ of ZnO is 0.35, then at this moment TCV can be down to zero basically, and k²Can be up to 0.56%, so just can obtain to have little size, wide passband and extraordinary Temperature performance the ground roll device arranged. Example 3-1 (embodiment 3)

With CZ technology growth langasite monocrystal, thick from this monocrystal cutting 0.35mm Matrix; Form SAW transducer at matrix surface, this transducer comprises: a cover input Interdigital electrode and output interdigital electrode; On thing surface wave transducer, form one with magnetron sputtering technique Layer ZnO film; Then, form one deck counter electrode films at ZnO film, consisted of the sound surface Wave device. Interdigital electrode and counter electrode films are formed by the Al evaporation. Interdigital electrode all is identical shaped Ordinary electrode, its thickness are 0.1 μ m, and electrode finger width d is 15 μ m, electrode finger spacing (4d) be 60 μ m, the right number of electrode finger is 40, between finger aperture be 60 λ (=3.6mm). Yet, when weak output signals, aperture between the finger of above-mentioned interdigital electrode Become 100 λ, other is constant. In addition, the normalized thickness when ZnO film surpasses 0.4 The time, electrode finger spacing reduces by half to 30 μ m, aperture also corresponding reduce by half to 1.8mm (=60 λ). The thickness of counter electrode films is 0.1 μ m.

According to the SAW device of embodiment 3 because in its structure, interdigital electrode and and its Opposed counter electrode films separates with ZnO film betwixt, so when ZnO film thickness approaches zero, Device just can not be worked; Because at this moment with short circuit has taken place in interdigital electrode and counter electrode films. Therefore, in this example, the minimum of a value of ZnO film normalization thickness h/λ is preset as 0.005. When the normalization thickness of device was 0.005, the thickness of interdigital electrode was 0.1 μ m, the electrode finger Spacing be 320 μ m (=λ), and 20 electrode fingers pair are arranged, its finger aperture is 5mm, Counter electrode films thickness is 0.07 μ m, and matrix thickness is 1mm.

In this example, the corner cut that cuts out from the langasite monocrystal when matrix and surface acoustic wave are at base When the direction of propagating on the body represented with Eulerian angles (φ, θ, ψ), φ, θ were respectively 0 ° and 90 °. ψ is used for determining the direction of propagation of X-axis and surface acoustic wave, the ψ value of selecting from overall area III Shown in Figure 32 A～40C. The selection of the thickness h of the ZnO film on the matrix is on should satisfying State normalization thickness h/λ=0.05～0.8. On each direction of propagation, measured the SAW velocity of wave, Electromechanical coupling factor k², and the variable quantity of SAW velocity of wave temperature coefficient TCV when h/ λ changes. The SAW velocity of wave is obtained by the centre frequency of wave filter, and electromechanical coupling factor k²Then utilize famous The Smith equivalent-circuit model obtains with the two ends admittance of measuring SAW transducer. Each direction Upper SAW velocity of wave, k²Be marked on Figure 32 A～40C with the measurement result of TCV.

When the normalization thickness h of ZnO film/λ increased, the wave mode of surface acoustic wave had just disappeared. Bulk wave has appearred. Therefore, the data that obtain after the bulk wave generation all do not mark.

SAW velocity of wave and k²Change curve show, if the corner cut harmony that matrix cuts out from crystal The surface direction of wave travel drops on overall area III, and then the SAW velocity of wave can drop to 2900m/s or lower. Compare with traditional ST quartz crystal, this more is conducive to reduce the size of SAW device. Also send out The electromechanical coupling factor that present overall area III obtains can be 0.1% or higher. So just may lead to The selection of crossing ZnO film thickness obtains much higher electromechanical coupling factor.

Below, detailed explanation is carried out in each zone:

As can be seen from Figure 32B, utilize the electromechanical coupling factor of the device of regional III-1 to have two Individual peak value: one the coefficient of coup that obtains is 0.22% at h/ λ=0.05 place, and another is at h/ λ=0.65 place, the coefficient of coup that obtains is 0.71%. Can find out from Figure 32 C. Here, the former is right The TCV that answers is-3ppm/ ℃, and TCV corresponding to the latter be-27ppm/ ℃; Will be to obtain foot Enough good temperature performances.

As can be seen from Figure 33B, utilize the electromechanical coupling factor of the device of regional III-2 to have two Individual peak value: one the coefficient of coup that obtains is 0.2% at h/ λ=0.05 place, and another is at h/ λ=0.6 place, the coefficient of coup that obtains is 0.3%. Can find out from Figure 33 C. Here, the former correspondence TCV be 29ppm/ ℃, TCV corresponding to the latter is 5ppm/ ℃; Enough good to obtain Temperature performance.

As can be seen from Figure 34B, utilize the electromechanical coupling factor of the device of regional III-3 to have two Individual peak value: one the coefficient of coup that obtains is 0.29% at h/ λ=0.05 place, and another is at h/ λ=0.45 place, the coefficient of coup that obtains is 0.12%. Can find out from Figure 34 C. Here, the former is right The TCV that answers is 40ppm/ ℃, and TCV corresponding to the latter is 31ppm/ ℃; Enough to obtain Good temperature performance.

As can be seen from Figure 35B, utilize the electromechanical coupling factor of the device of regional III-4 to have two Individual peak value: one the coefficient of coup that obtains is 0.37% at h/ λ=0.05 place, and another is at h/ λ=0.45 place, the coefficient of coup that obtains is 0.2%. Can find out from Figure 35 C. Here, the former is right The TCV that answers is 32ppm/ ℃, and TCV corresponding to the latter is 15ppm/ ℃; Enough to obtain Good temperature performance.

As can be seen from Figure 36B, utilize the electromechanical coupling factor of the device of regional III-5 to have two Individual peak value: one the coefficient of coup that obtains is 0.36% at h/ λ=0.05 place, and another is at h/ λ=0.4 place, the coefficient of coup that obtains is 0.2%. Can find out from Figure 36 C. Here, the former correspondence TCV be 27ppm/ ℃, TCV corresponding to the latter is 14ppm/ ℃; Enough good to obtain Temperature performance.

As can be seen from Figure 37B, utilize the electromechanical coupling factor of the device of regional III-6 to have two Individual peak value: one the coefficient of coup that obtains is 0.29% at h/ λ=0.05 place, and another is at h/ λ=0.4 place, the coefficient of coup that obtains is 0.5%. Can find out from Figure 37 C. Here, the former correspondence TCV be 25ppm/ ℃, TCV corresponding to the latter is 16ppm/ ℃; Enough good to obtain Temperature performance.

As can be seen from Figure 38B, utilize the electromechanical coupling factor of the device of regional III-7 to have two Individual peak value: one the coefficient of coup that obtains is 0.24% at h/ λ=0.05 place, and another is at h/ λ=0.45 place, the coefficient of coup that obtains is 0.65%. Can find out from Figure 38 C. Here, the former is right The TCV that answers is 31ppm/ ℃, and TCV corresponding to the latter is 18ppm/ ℃; Enough to obtain Good warm reflexive energy.

As can be seen from Figure 39B, utilize the electromechanical coupling factor of the device of regional III-8 to have two Individual peak value: one the coefficient of coup that obtains is 0.18% at h/ λ=0.05 place, and another is at h/ λ=0.4 place, the coefficient of coup that obtains is 0.45%. Can find out from Figure 39 C. Here, the former is right The TCV that answers is 39ppm/ ℃, and TCV corresponding to the latter is 31ppm/ ℃; Enough to obtain Good temperature performance.

As can be seen from Figure 40B, utilize the electromechanical coupling factor of the device of regional III-9 to have two Individual peak value: one the coefficient of coup that obtains is 0.13% at h/ λ=0.05 place, and another is at h/ λ=0.55 place, the coefficient of coup that obtains is 0.6%. Can find out from Figure 40 C. Here, the former is right The TCV that answers is 29ppm/ ℃, and TCV corresponding to the latter is 7ppm/ ℃; Enough good to obtain Temperature performance.

As can be seen from Figure 41B, utilize the electromechanical coupling factor of the device of regional III-10 to have two Individual peak value: one the coefficient of coup that obtains is 0.14% at h/ λ=0.05 place, and another is at h/ λ=0.6 place, the coefficient of coup that obtains is 0.89%. Can find out from Figure 41 C. Here, the former is right The TCV that answers is-2ppm/ ℃, and TCV corresponding to the latter be-27ppm/ ℃; Will be to obtain foot Enough good temperature performances.

Example 3-2 (embodiment 3)

Press the SAW device that example 3-1 makes, different from 3-1 is: φ and θ are respectively Be 0 ° and 90 °, and be used for determining that the ψ value of X-axis or acoustic surface wave propagation direction is from-80 ° To-66 °, select a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is at regional III In-1. Measured TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 42. Also measured k²The relation of-h/ λ the results are shown in Figure 43.

On the one hand, as can be seen from Figure 12, at regional III-1, can obtain the zero-temperature coefficient performance, And change corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave. On the other hand, as can be seen from Figure 43, when the ZnO film thickening, electromechanical coupling factor is tending towards Become big. Therefore, if in order to obtain the zero-temperature coefficient performance selected ZnO film thickness, simultaneously for Obtain enough big electromechanical coupling factor and the selected direction of propagation, so just can obtain to have zero temperature The SAW device of degree performance and big electromechanical coupling factor. For example, if direction of propagation ψ be-78 °, normalization thickness h/λ of ZnO is 0.05, and then at this moment TCV can be down to zero basically, And k²Can be up to 0.21%, so just can obtain to have little size, wide passband and very good The SAW device of temperature performance. Example 3-3 (embodiment 3)

Press the SAW device that example 3-1 makes, different from 3-1 is: φ and θ are respectively Be 0 ° and 90 °, and the ψ value that is used for determining X-axis or acoustic surface wave propagation direction from 66 ° to 80 ° are selected a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is at regional III-10 In. Measure TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 14. Also measured k²The relation of-h/ λ the results are shown in Figure 45.

On the one hand, as can be seen from Figure 44, at regional III-10, can obtain the zero-temperature coefficient performance, And change corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave. On the other hand, as can be seen from Figure 15, when the ZnO film thickening, electromechanical coupling factor is more than change Greatly. Therefore, if in order to obtain enough big electromechanical coupling factor selected ZnO film thickness, The selected direction of propagation in order to obtain the zero-temperature coefficient performance so just can obtain to have zero-temperature coefficient simultaneously The SAW device of performance and big electromechanical coupling factor. For example, if direction of propagation ψ is 70 °, normalization thickness h/λ of ZnO is 0.35, then at this moment TCV can be down to zero basically, and k²Can be up to 0.44%, so just can obtain to have little size, wide passband and extraordinary Temperature performance the ground roll device arranged. Example 4-1 (embodiment 4)

With CZ technology growth langasite monocrystal, thick from this monocrystal cutting 0.35mm Matrix. Form counter electrode films at matrix surface. On the counter electrode films surface, spatter with magnetic control then Penetrate technology and form the layer of ZnO film. Form SAW transducer on the ZnO film surface again, To consist of SAW device; This transducer comprises: a cover input interdigital electrode and the interdigital electricity of output The utmost point; Interdigital electrode and counter electrode films form with the Al evaporation. Interdigital electrode all is identical shaped common Electrode, its thickness are 0.1 μ m, and electrode finger width d is 15 μ m. Electrode finger spacing is 60 μ m (=4d=λ), the right number of electrode finger is 40, between finger aperture be 60 λ (=3.6mm). Yet, when weak output signals, aperture between the finger of above-mentioned interdigital electrode Become 100 λ, other is constant. In addition, when the normalization thickness of ZnO film surpasses 0.4, Then electrode finger spacing (=λ) reduce by half to 30 μ m, aperture is corresponding reducing by half to 1.8mm also (=60 λ).

According to the SAW device of embodiment 4 because in its structure, interdigital electrode and and its Opposed counter electrode films separates with ZnO film betwixt, so when ZnO film thickness approaches zero, Device just can not be worked; At this moment because between interdigital electrode and counter electrode films short circuit has taken place. Therefore, in this example, the minimum of a value of ZnO film normalization thickness h/λ is preset as 0.005. When the normalization thickness of device was 0.005, then the thickness of interdigital electrode was 0.1 μ m, and electrode refers to Stripe pitch is 320 μ m, and 20 electrode fingers pair are arranged, and the finger aperture is 5mm, anti-electricity Utmost point film thickness is 0.07 μ m, and substrate thickness is 1mm.

In this example, the corner cut that cuts out from the langasite monocrystal when matrix and surface acoustic wave are at base When the direction of propagating on the body represented with Eulerian angles (φ, θ, ψ), φ, θ were respectively 0 ° and 90 °. And ψ is used for determining the direction of propagation of X-axis and surface acoustic wave, the ψ that selects from overall area IV Value is shown in Figure 47 A～56C. The selection of the thickness h of the ZnO film on the matrix should be satisfied Above-mentioned normalization thickness h/λ=0.05～0.8. On each direction of propagation, measured the SAW ripple Speed, electromechanical coupling factor k², and the variation of SAW velocity of wave temperature coefficient TCV when h/ λ changes Amount. The SAW velocity of wave is obtained by the centre frequency of wave filter, and electromechanical coupling factor k²Then utilize work The Smith equivalent-circuit model of name. Obtain with the two ends admittance of measuring SAW transducer. Whenever SAW velocity of wave on the individual direction, k²Be marked on Figure 47 A～56C with the measurement result of TCV.

Along with the increase of ZnO film normalization thickness h λ, the wave mode of surface acoustic wave has just disappeared. Bulk wave has appearred. Therefore, the data that obtain after the bulk wave generation all do not mark.

The SAW velocity of wave and, k²Change curve show, if the corner cut harmony that matrix cuts out from crystal The surface direction of wave travel drops on overall area IV, and then the SAW velocity of wave can drop to 2900m/s or lower. Compare with traditional ST quartz crystal, this more is conducive to reduce the size of SAW device. Unconsciously Discovery can be 0.1% or higher at the electromechanical coupling factor that overall area IV obtains. So just may Selection by ZnO film thickness obtains much higher electromechanical coupling factor.

Below, detailed explanation is carried out in each zone.

Can be found out by Figure 47 B, 47C, utilize the device of regional IV-1, when h/ λ=0.8 The time, its electromechanical coupling factor can up to 0.88%, at this moment, TCV=-31ppm/ ℃, have Enough good temperature performances.

Can be found out by Figure 48 B, 48C, utilize the device of regional IV-2, when h/ λ=0.6 The time, its electromechanical coupling factor can up to 0.6%, at this moment, TCV=6ppm/ ℃, have enough Good temperature performance.

By Figure 49 B, 49C can find out, utilizes the device of regional IV-3, when h/ λ=0.4 The time, its electromechanical coupling factor can up to 0.39%, at this moment, TCV=29ppm/ ℃, have foot Enough good temperature performances.

Can be found out by Figure 50 B, 50C, utilize the device of regional IV-4, when h/ λ=0.45 The time, its electromechanical coupling factor can up to 0.52%,, TCV=17ppm/ ℃, have foot here Enough good temperature performances.

Can be found out by Figure 51 B, 51C, utilize the device of regional IV-5, when h/ λ=0.4 The time, its electromechanical coupling factor can up to 0.46%,, TCV=15ppm/ ℃, have foot here Enough good temperature performances.

Can be found out by Figure 52 B, 52C, utilize the device of regional IV-6, when h/ λ=0.4 The time, its electromechanical coupling factor can up to 0.46%, at this moment, TCV=15ppm/ ℃, have foot Enough good temperature performances.

Can be found out by Figure 53 B, 53C, utilize the device of regional IV-7, when h/ λ=0.45 The time, its electromechanical coupling factor can up to 0.52%, at this moment, TCV=17ppm/ ℃, have foot Enough good temperature performances.

By Figure 54 B, 54C can find out, utilizes the device of regional IV-8, when h/ λ=0.4 The time, its electromechanical coupling factor can up to 0.39%, at this moment, TCV=29ppm/ ℃, have foot Enough good temperature performances.

Can be found out by Figure 55 B, 55C, utilize the device of regional IV-9, when h/ λ=0.6 The time, its electromechanical coupling factor can up to 0.6%,, TCV=6ppm/ ℃, have enough here Good temperature performance.

Can be found out by Figure 56 B, 56C, utilize the device of regional IV-10, when h/ λ=0.8 The time, its electromechanical coupling factor can up to 0.88%, here, TCV=-32ppm/ ℃, have Enough good temperature performances. Example 4～2 (embodiment 4)

Press the SAW device that example 4-1 makes, different from 4-1 is: φ and θ are respectively Be 0 ° and 90 °, and be used for determining that the ψ value of X-axis or acoustic surface wave propagation direction is from-80 ° To-66 °, select a sub-value every 2 °. Should be understood that these φ, θ and ψ value are at regional IV-In 1. Measure TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 58.

On the one hand, can find out from Figure 57, at regional IV-1, can obtain the zero-temperature coefficient performance, And become corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave Change. On the other hand, can find out from Figure 58 that when the ZnO film thickening, electromechanical coupling factor becomes Yu Bianda. Therefore, if in order to obtain enough big electromechanical coupling factor selected ZnO film Thickness, the selected direction of propagation in order to obtain the zero-temperature coefficient performance so just can obtain to have simultaneously The SAW device of zero-temperature coefficient performance and big electromechanical coupling factor. For example, if direction of propagation ψ Be-70 °, normalization thickness h/λ of ZnO is 0.35, and then at this moment TCV can be down to basically Zero, and k²Can be up to 0.42%, so just can obtain to have little size, wide passband and non-The SAW device of normal good temperature performance. Example 4-3 (embodiment 4)

Press the SAW device that example 4-1 makes, different from 4-1 is: φ and θ are respectively Be 0 ° and 90 °, and the ψ value that is used for determining X-axis and acoustic surface wave propagation direction from 66 ° to 80 °, select a sub-value every 2 °. Should be pointed out that these φ, θ, the ψ value is at regional IV-10 In. Measure TCV-h/ λ (normalization thickness) relation of these devices, the results are shown in Figure 59. Also measured k²The relation of-h/ λ the results are shown in Figure 60.

On the one hand, can find out from Figure 59, at regional IV-10, can obtain the zero-temperature coefficient performance, And become corresponding to the thickness of the ZnO film of the zero-temperature coefficient performance direction of propagation with surface acoustic wave Change. On the other hand, can find out from Figure 60 that when the ZnO film thickening, electromechanical coupling factor becomes Yu Bianda. Therefore, if selected ZnO film is thick in order to obtain enough big electromechanical coupling factor Degree, the selected direction of propagation in order to obtain the zero-temperature coefficient performance so just can obtain to have zero simultaneously The SAW device of temperature performance and big electromechanical coupling factor. For example, if direction of propagation ψ Be 70 °, normalization thickness h/λ of ZnO is 0.35, and then at this moment TCV can be down to zero basically, And k²Can be up to 0.42%, so just can obtain to have little size, wide passband and very good The SAW device of temperature performance.

Advantage of the present invention is apparent by the result of above each example.

Claims

1. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

Be arranged to cover the piezoelectric film on the surface of the above-mentioned surface of above-mentioned matrix and above-mentioned interdigital electrode; Wherein:

Above-mentioned matrix is the langasite monocrystal that belongs to point group 32, and when the corner cut of the above-mentioned matrix that cuts out from the langasite monocrystal and the direction of propagation of surface acoustic wave on above-mentioned matrix with Eulerian angles (φ, θ, ψ) during expression, wherein:

-5°≤φ≤5°

85°≤θ≤95°

-90 °≤ψ＜-70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.2 is to 0.8

Wherein, h is the thickness of above-mentioned ZnO film, and λ is the wavelength of surface acoustic wave.

2. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-70 °≤ψ＜-50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.25 is to 0.7

3. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-50 °≤ψ＜-35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.25 is to 0.45

4. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-35 °≤ψ＜-25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.5

5. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-25 °≤ψ≤-10 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

6. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

10 °≤ψ＜25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.4

7. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

25 °≤ψ＜35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

8. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

35 °≤ψ＜50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.4

9. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

50 °≤ψ＜70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.15 is to 0.7

10. SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

70 °≤ψ＜90 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.15 is to 0.8

11. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

In the lip-deep interdigital electrode of above-mentioned piezoelectric film; Wherein:

-5°≤φ≤5°

85°≤θ≤95°

-90 °≤ψ＜-70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8

12. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-70 °≤ψ＜-50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.75

13. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-50 °≤ψ＜-35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

14. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-35 °≤ψ＜-25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.5

15. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-25 °≤ψ≤-10 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

16. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

10 °≤ψ＜25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.4

17. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

25 °≤ψ＜35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

18. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

35 °≤ψ＜50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.4

19. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

50 °≤ψ＜70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.7

20. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Piezoelectric film on described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

70 °≤ψ＜90 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8

21. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

Be arranged to cover the piezoelectric film on the surface of the above-mentioned surface of above-mentioned matrix and above-mentioned interdigital electrode, and one in the lip-deep counter electrode films of described piezoelectric film; Wherein:

-5°≤φ≤5°

85°≤θ≤95°

-90 °≤ψ＜-70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.1 or 0.3≤h/ λ≤0.8

22. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-70 °≤ψ＜-50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.1 or 0.35≤h/ λ≤0.8

23. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-50 °≤ψ＜-35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.15 or 0.35≤h/ λ≤0.5

24. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-35 °≤ψ＜-25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.15 or 0.3≤h/ λ≤0.5

25. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-25 °≤ψ≤-10 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.15 or 0.3≤h/ λ≤0.45

26. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

10 °≤ψ＜25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

27. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

25 °≤ψ＜35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.5

28. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

35 °≤ψ＜50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/λ≤0.45

29. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

50 °≤ψ＜70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.05 or 0.2≤h/ λ≤0.8

30. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Interdigital electrode on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

70 °≤ψ＜90 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

0＜h/ λ≤0.05 or 0.25≤h/ λ≤0.8

31. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

Piezoelectric film on above-mentioned counter electrode films, and in the lip-deep interdigital electrode of described piezoelectric film; Wherein:

-5°≤φ≤5°

85°≤θ≤95°

-90 °≤ψ≤-70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8

32. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-70 °≤ψ＜-50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8

33. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-50 °≤ψ＜-35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.45

34. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-35 °≤ψ＜-25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.5

35. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

-25 °≤ψ≤-10 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.45

36. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

10 °≤ψ＜25 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.45

37. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

25 °≤ψ＜35 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.5

38. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

35 °≤ψ＜50 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.45

39. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

50 °≤ψ＜70 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8

40. a SAW (Surface Acoustic Wave) device comprises:

Matrix,

Counter electrode films on the described matrix surface, and

-5°≤φ≤5°

85°≤θ≤95°

70 °≤ψ＜90 °, and

Described piezoelectric film is the ZnO film of a c-axle orientation, satisfies

H/ λ=0.05 is to 0.8