JPH11308069A - Surface acoustic wave device - Google Patents
Surface acoustic wave deviceInfo
- Publication number
- JPH11308069A JPH11308069A JP10124123A JP12412398A JPH11308069A JP H11308069 A JPH11308069 A JP H11308069A JP 10124123 A JP10124123 A JP 10124123A JP 12412398 A JP12412398 A JP 12412398A JP H11308069 A JPH11308069 A JP H11308069A
- Authority
- JP
- Japan
- Prior art keywords
- surface acoustic
- acoustic wave
- silicon dioxide
- electrode
- dioxide film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は弾性表面波デバイス
に関し、周波数温度特性を改善した特に四ほう酸リチウ
ム単結晶圧電基板を用いた弾性表面波デバイスのに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device, and more particularly, to a surface acoustic wave device using a lithium tetraborate single crystal piezoelectric substrate with improved frequency temperature characteristics.
【0002】[0002]
【従来の技術】近年、弾性表面波デバイス(以下、SA
Wデバイスと称す)は高性能、小型、量産性等の特徴を
有することから多くの通信分野で用いられ、特に携帯電
話等の普及の一翼を担っている。SAWデバイスの周波
数温度特性、結合係数等の諸特性は、周知のようにそれ
に用いる圧電基板、切断角度、電極膜厚等によりほぼ決
定される。SAWデバイスに用いられる圧電材料として
は、水晶、タンタル酸リチウム、ニオブ酸リチウム等の
単結晶があり、例えば、圧電基板にSTカット水晶基板
を用いると比較的狭い帯域(比帯域幅が0.05%程度)を
有する共振子型フィルタが得られ、36゜Yカットタンタ
ル酸リチウムを用いると比較的広い帯域(比帯域幅2〜
3%程度)の共振子型フィルタが構成できることはよく
知られている。2. Description of the Related Art In recent years, surface acoustic wave devices (hereinafter referred to as SAs) have been developed.
W devices) are used in many communication fields because of their characteristics such as high performance, small size, and mass productivity, and play a part in the spread of mobile phones and the like. As is well known, various characteristics such as the frequency temperature characteristic and the coupling coefficient of the SAW device are substantially determined by the piezoelectric substrate, the cutting angle, the electrode film thickness and the like used therein. Piezoelectric materials used for SAW devices include single crystals such as quartz, lithium tantalate, and lithium niobate. For example, when an ST-cut quartz substrate is used for a piezoelectric substrate, a relatively narrow band (fractional bandwidth is about 0.05%) ) Is obtained, and a relatively wide band (fractional bandwidth 2 to 2) is obtained by using 36 ° Y-cut lithium tantalate.
It is well known that a resonator type filter (about 3%) can be formed.
【0003】ところが、近年急速に普及しつつある携帯
電話のIFフィルタとして、中心周波数100〜300MH
z、帯域幅0.1〜0.3%程度の中帯域のフィルタの要求が
増大している。そこで、STカット水晶基板と36゜Yカ
ットタンタル酸リチウムとのほぼ中間の電気機械結合係
数を有する45゜Xカット四ほう酸リチウム基板が前記中
帯域フィルタの仕様を満たす共振子型フィルタを構成す
る上で注目されている。However, in recent years, as an IF filter for a cellular phone, which has been rapidly spreading, a center frequency of 100 to 300 MHz is used.
There is an increasing demand for a middle band filter having a z and a bandwidth of about 0.1 to 0.3%. Therefore, a 45 ° X-cut lithium tetraborate substrate having an electromechanical coupling coefficient substantially intermediate between that of the ST-cut quartz substrate and the 36 ° Y-cut lithium tantalate constitutes a resonator-type filter satisfying the specifications of the mid-band filter. It is attracting attention.
【0004】[0004]
【発明が解決しようとする課題】しかしながら、上記の
45゜Xカット四ほう酸リチウム基板を用いた共振子型フ
ィルタの周波数温度特性は、周知のように上に凸の2次
曲線Δf/f = −3×10-8(T−Tp)2で表すことでき、頂点
温度Tp(2次曲線の温度特性で零温度係数を呈する温
度)で零温度係数を有するものの、頂点温度Tpが常温よ
りも高温側、例えばIDT電極を膜厚1%λのアルミニ
ウムで形成すると頂点温度Tpは約39℃となるため、低温
側において温度による周波数変化量Δf/fが大きくな
り、−20℃〜70℃の温度範囲において、フィルタの
中心周波数の温度特性100ppmという要求仕様を満た
すことができず100ppm〜150ppmとなり製品の歩留
まりが大幅に悪化するという問題があった。本発明は上
記問題を解決するためになされたものであって、比帯域
幅が0.1〜0.3%程度の中帯域で、周波数温度特性の優れ
たSAWフィルタを提供することを目的とする。SUMMARY OF THE INVENTION
As is well known, the frequency-temperature characteristic of the resonator type filter using the 45 ° X-cut lithium tetraborate substrate is expressed by an upwardly convex quadratic curve Δf / f = −3 × 10 −8 (T−Tp) 2 . Although it has a zero temperature coefficient at the apex temperature Tp (a temperature exhibiting a zero temperature coefficient in the temperature characteristic of the quadratic curve), the apex temperature Tp is higher than room temperature, for example, when the IDT electrode is made of aluminum having a film thickness of 1% λ. Since the peak temperature Tp becomes about 39 ° C. when formed, the amount of frequency change Δf / f due to temperature on the low temperature side becomes large, and the temperature characteristic of the center frequency of the filter is 100 ppm in the temperature range of −20 ° C. to 70 ° C. There was a problem that the specifications could not be satisfied and the product yield was 100 ppm to 150 ppm, and the product yield was significantly deteriorated. The present invention has been made to solve the above-described problem, and has as its object to provide a SAW filter having a medium frequency band of about 0.1 to 0.3% and excellent frequency temperature characteristics.
【0005】[0005]
【課題を解決するための手段】上記目的を達成するため
に本発明に係る弾性表面波デバイスの請求項1記載の発
明は、四ほう酸リチウム圧電基板の主面上に二酸化シリ
コン膜を形成しその上に励起される表面波の伝搬方向に
沿って少なくとも1つのIDT電極と両側に反射器を配
置して構成する表面波共振子において、前記二酸化シリ
コン膜の膜厚Hsと励起される表面波の波長λとの比Hs
/λを 5×10-4 ≦ Hs/λ ≦ 5×10-3 としたことを特徴とする弾性表面波デバイス。請求項2
記載の発明は、複数のIDT電極を表面波の伝搬方向に
沿って近接配置し縦結合多重モード表面波フィルタとし
たことを特徴とする請求項1記載の弾性表面波デバイス
である。請求項3記載の発明は、IDT電極とその両側
に反射器を配置して構成する表面波共振子を表面波の伝
搬方向と並行して近接配置して横結合多重モード表面波
フィルタとしたことを特徴とする請求項1記載の弾性表
面波デバイスである。According to a first aspect of the present invention, there is provided a surface acoustic wave device according to the present invention, wherein a silicon dioxide film is formed on a main surface of a lithium tetraborate piezoelectric substrate. In the surface acoustic wave resonator configured by arranging at least one IDT electrode and reflectors on both sides along the propagation direction of the surface wave to be excited, the thickness Hs of the silicon dioxide film and the Ratio Hs to wavelength λ
A surface acoustic wave device wherein / λ is set to 5 × 10 −4 ≦ Hs / λ ≦ 5 × 10 −3 . Claim 2
The described invention is the surface acoustic wave device according to claim 1, wherein a plurality of IDT electrodes are arranged close to each other along the propagation direction of the surface acoustic wave to form a longitudinally coupled multimode surface acoustic wave filter. According to a third aspect of the present invention, a laterally coupled multi-mode surface acoustic wave filter is provided in which an IDT electrode and a surface acoustic wave resonator having reflectors arranged on both sides thereof are arranged close to each other in parallel with the propagation direction of the surface acoustic wave. The surface acoustic wave device according to claim 1, wherein:
【0006】[0006]
【発明の実施の形態】以下本発明を図面に示した実施の
形態に基づいて詳細に説明する。図1(a)は本発明に
係るSAWデバイスの構成を示す平面図、同図(b)は
A−A線における断面の一部を示す図である。本発明に
係るSAWデバイスは45°Xカット四ほう酸リチウム基
板1の主面上に二酸化シリコン(SiO2)の薄膜2を蒸着
等の手法を用いて形成し、該膜2の上にIDT電極3、
グレーティング反射器4a、4b(以下、反射器と称
す)をアルミニウム合金を用いて通常のフォトリソ手法
で形成したものである。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. FIG. 1A is a plan view showing a configuration of a SAW device according to the present invention, and FIG. 1B is a diagram showing a part of a cross section taken along line AA. In the SAW device according to the present invention, a thin film 2 of silicon dioxide (SiO 2 ) is formed on the main surface of a 45 ° X-cut lithium tetraborate substrate 1 by a method such as evaporation, and an IDT electrode 3 is formed on the film 2. ,
The grating reflectors 4a and 4b (hereinafter, referred to as reflectors) are formed by an ordinary photolithography method using an aluminum alloy.
【0007】二酸化シリコン薄膜2上に形成したIDT
電極3及び反射器4a、4bについて説明すると、45°
Xカット四ほう酸リチウム基板1に励起される表面波の
伝搬方向に沿ってIDT電極3を配置すると共に、該電
極3の両側に反射器4a、4bを配設する。IDT電極
3はそれぞれ互いに間挿し合う複数本の電極指を有する
一対のくし形電極により構成され、IDT電極3の一方
のくし形電極は入力端子INに接続し、他方のくし形電極
は出力端子OUTに接続する。周知のように、IDT電極
3によって励起される複数の表面波の中で所望の表面波
(通常は最低次モード)のみを反射器4a、4bの間に
閉じ込め、SAW共振子として動作させる。IDT formed on silicon dioxide thin film 2
The electrode 3 and the reflectors 4a and 4b are described as follows.
The IDT electrode 3 is arranged along the propagation direction of the surface wave excited by the X-cut lithium tetraborate substrate 1, and reflectors 4a and 4b are arranged on both sides of the electrode 3. The IDT electrode 3 is composed of a pair of comb-shaped electrodes each having a plurality of electrode fingers interposed therebetween. One of the IDT electrodes 3 is connected to the input terminal IN, and the other comb-shaped electrode is connected to the output terminal. Connect to OUT. As is well known, of the plurality of surface waves excited by the IDT electrode 3, only a desired surface wave (usually the lowest-order mode) is confined between the reflectors 4a and 4b to operate as a SAW resonator.
【0008】本願発明者は、図1(b)に示したように
45°Xカット四ほう酸リチウム基板1の上に形成した二
酸化シリコン膜2が、SAWデバイスの周波数温度特
性、Q値にどのような影響を及ぼすかについて二酸化シ
リコン膜2の膜厚を変えて種々の実験を行った。図2
は、前記二酸化シリコン膜2の膜厚Hsと頂点温度Tpの関
係を示す図である。二酸化シリコン膜2の膜厚Hsを励起
される表面波の波長λで規準化し、その値Hs/λを横軸
にとり、頂点温度Tpと二酸化シリコン膜2の厚さを零と
した場合の頂点温度Tp0との差、即ち頂点温度偏差ΔTp=
Tp−Tp0を縦軸とした場合の図である。 図2より、二
酸化シリコン膜2の膜厚Hs/λと頂点温度Tpの関係は、
膜厚Hs/λを厚くするに従い頂点温度Tpは低温側に移動
していく。頂点温度偏差ΔTpと膜厚Hs/λとの関係は次
の式で近似することができる。 ΔTp =-1.0423×106×(Hs/λ)2−1.2574×103×(Hs/λ) (1) この式より、二酸化シリコン膜2の膜厚Hs/λを0.0005
以上厚くすれば、周波数温度特性の頂点温度Tpを1℃以
上低温側に移動しうることが分かる。[0008] The inventor of the present application has proposed a method as shown in FIG.
By changing the thickness of the silicon dioxide film 2 by changing the thickness of the silicon dioxide film 2 on how the silicon dioxide film 2 formed on the 45 ° X-cut lithium tetraborate substrate 1 affects the frequency temperature characteristics and the Q value of the SAW device. An experiment was performed. FIG.
FIG. 3 is a diagram showing the relationship between the thickness Hs of the silicon dioxide film 2 and the peak temperature Tp. The thickness Hs of the silicon dioxide film 2 is normalized by the wavelength λ of the excited surface wave, the value Hs / λ is plotted on the horizontal axis, and the peak temperature Tp and the peak temperature when the thickness of the silicon dioxide film 2 are set to zero. Difference from Tp 0 , that is, peak temperature deviation ΔTp =
Is a diagram of a case where the Tp-tp 0 as ordinate. From FIG. 2, the relationship between the thickness Hs / λ of the silicon dioxide film 2 and the peak temperature Tp is:
As the film thickness Hs / λ increases, the peak temperature Tp moves to the lower temperature side. The relationship between the peak temperature deviation ΔTp and the film thickness Hs / λ can be approximated by the following equation. ΔTp = −1.0423 × 10 6 × (Hs / λ) 2 −1.2574 × 10 3 × (Hs / λ) (1) From this equation, the thickness Hs / λ of the silicon dioxide film 2 is 0.0005.
It can be seen that if the thickness is made thicker, the peak temperature Tp of the frequency temperature characteristic can be shifted to a low temperature side by 1 ° C. or more.
【0009】一方、図3は二酸化シリコン膜2の膜厚Hs
/λとSAW共振子のQ値の関係を示した図であり、膜
厚Hs/λを厚くするに従いQ値は小さくなっていく。こ
の図より、二酸化シリコン膜2の膜厚Hs/λとSAWデ
バイスのQの関係を求めると次式で近似することができ
る。 Q=-8.3217×105×(Hs/λ)+5.5054×103 (2) 一般に、共振子は該共振子Q値をその容量比γで割った
値で表すフィギュアオブメリットMが10以上が望ましい
と云われている。45°Xカット四ホウ酸リチウム基板を
SAWデバイスに用いる場合、容量比γはおおよそγ=
125となるのでQ値が1250以上が望ましく、図3よりこ
の値に対応する二酸化シリコン膜2の膜厚Hs/λを求め
ると、Hs/λ= 0.005が得られる。FIG. 3 shows the thickness Hs of the silicon dioxide film 2.
FIG. 4 is a diagram showing the relationship between / λ and the Q value of a SAW resonator, where the Q value decreases as the film thickness Hs / λ increases. From this figure, the relationship between the thickness Hs / λ of the silicon dioxide film 2 and the Q of the SAW device can be approximated by the following equation. Q = −8.3217 × 10 5 × (Hs / λ) + 5.5054 × 10 3 (2) Generally, a resonator has a figure of merit M of 10 or more expressed by a value obtained by dividing the resonator Q value by its capacitance ratio γ. Is said to be desirable. When a 45 ° X-cut lithium tetraborate substrate is used for a SAW device, the capacitance ratio γ is approximately γ =
Since the value is 125, the Q value is desirably 1250 or more. When the film thickness Hs / λ of the silicon dioxide film 2 corresponding to this value is obtained from FIG. 3, Hs / λ = 0.005 is obtained.
【0010】二酸化シリコン膜2の膜厚Hs/λを厚くし
ていけば、式(1)に従い頂点温度Tpを低温側に移動さ
せることは可能であるが、膜厚Hs/λの増加につれてQ
値が劣化することになる。従って二酸化シリコン膜2の
膜厚Hs/λに可変範囲として、フィギュアオブメリットM
が10以上となると共に頂点温度Tpが低温側に1℃以上
移動させるのに必要な二酸化シリコン膜2として 5×10-4≦ Hs/λ≦5×10-3 (3) が得られる。二酸化シリコン膜2の膜厚Hs/λをこの範
囲に選べば、高いQ値(>1250)を確保した上で頂点温
度Tpを低温側に移動させることができる。例えば、図1
に示した一端子対SAW共振子において、圧電基板1に
45°Xカット四ほう酸リチウム基板を用い、IDT電極
3の対数を17対、反射器4a、4bの電極指本数を400
本とした場合、二酸化シリコン膜2の膜厚H/λを0.0035
5に設定すると、その頂点温度Tpは約22℃となり、二酸
化シリコン膜2がない場合のSAW共振子の頂点温度Tp
0に比べて約17℃も低温側にシフトさせることができ
た。なお、このときの共振子のQ値は約2200であった。If the thickness Hs / λ of the silicon dioxide film 2 is increased, it is possible to move the peak temperature Tp to the lower temperature side according to the equation (1), but Q increases as the thickness Hs / λ increases.
The value will be degraded. Therefore, the variable range of the thickness Hs / λ of the silicon dioxide
Is 10 or more, and 5 × 10 −4 ≦ Hs / λ ≦ 5 × 10 −3 (3) is obtained as the silicon dioxide film 2 necessary for moving the peak temperature Tp to the low temperature side by 1 ° C. or more. If the thickness Hs / λ of the silicon dioxide film 2 is selected in this range, the peak temperature Tp can be moved to a lower temperature side while securing a high Q value (> 1250). For example, FIG.
In the one-port SAW resonator shown in FIG.
Using a 45 ° X-cut lithium tetraborate substrate, the number of IDT electrodes 3 is 17 and the number of electrode fingers of reflectors 4a and 4b is 400.
In the case where the thickness is H, the thickness H / λ of the silicon dioxide film 2 is
When set to 5, the peak temperature Tp is about 22 ° C., and the peak temperature Tp of the SAW resonator without the silicon dioxide film 2 is set.
The temperature could be shifted to a lower temperature side by about 17 ° C. as compared to 0 . The Q value of the resonator at this time was about 2200.
【0011】以上はSAWデバイスの基本的構成である
SAW共振子で本発明を説明したが、本発明は例えば図
4に示す1次−3次縦結合二重モードSAWフィルタに
も適用できる。即ち、45°Xカット四ほう酸リチウム基
板1上に二酸化シリコン膜2を形成し、その上にIDT
電極5、6、7を励起される表面波に沿って近接配置
し、該IDT電極5、6、7の両側に反射器8a、8b
を配設して1次−3次縦結合二重モードSAWフィルタ
を構成する。このようにして構成された1次−3次縦結
合二重モードSAWフィルタの周波数温度特性は、その
頂点温度Tpを二酸化シリコン膜2の膜厚Hs/λにより低
温側に移動させることが可能となり、頂点温度Tpを所望
の温度に設定することができる。以上は本発明を1次−
3次縦結合二重モードSAWフィルタに適用した場合を
説明したが、本発明はこれに限らず他の縦結合多重モー
ドSAWフィルタに適用できることは云うまでもない。Although the present invention has been described above with reference to a SAW resonator which is a basic configuration of a SAW device, the present invention can be applied to, for example, a first-order to third-order longitudinally-coupled dual-mode SAW filter shown in FIG. That is, a silicon dioxide film 2 is formed on a 45 ° X-cut lithium tetraborate substrate 1 and an IDT is formed thereon.
The electrodes 5, 6, 7 are arranged close to each other along the surface wave to be excited, and reflectors 8a, 8b are provided on both sides of the IDT electrodes 5, 6, 7 respectively.
Are arranged to constitute a first-order / third-order longitudinally-coupled dual-mode SAW filter. The frequency temperature characteristic of the primary-tertiary-order longitudinally-coupled dual-mode SAW filter thus configured is such that its peak temperature Tp can be shifted to a lower temperature side by the thickness Hs / λ of the silicon dioxide film 2. , The peak temperature Tp can be set to a desired temperature. The above describes the present invention as primary-
The case where the present invention is applied to a third-order longitudinally-coupled dual-mode SAW filter has been described. However, it goes without saying that the present invention is not limited to this and can be applied to other longitudinally-coupled multi-mode SAW filters.
【0012】一方、本発明を図5に示す横結合二重モー
ドSAWフィルタに適用すると、該フィルタの周波数温
度特性を改善できる。図5に示すように45°Xカット四
ほう酸リチウム基板1上に二酸化シリコン膜2を形成
し、その上にIDT電極9と反射器10a、10bとか
らなる共振子とIDT電極11と反射器12a、12b
とからなる共振子を近接併置して横結合二重モードSA
Wフィルタを構成する。このようにして構成された横結
合二重モードSAWフィルタの周波数温度特性は、その
頂点温度Tpを二酸化シリコン膜2の膜厚Hs/λにより低
温側に移動させることが可能となり、頂点温度Tpを所望
の温度に設定することができる。以上は本発明を横結合
二重モードSAWフィルタに適用した場合を説明した
が、本発明は他の横結合多重モードSAWフィルタに適
用できることは云うまでもない。On the other hand, when the present invention is applied to the laterally coupled dual mode SAW filter shown in FIG. 5, the frequency temperature characteristics of the filter can be improved. As shown in FIG. 5, a silicon dioxide film 2 is formed on a 45 ° X-cut lithium tetraborate substrate 1, and a resonator including an IDT electrode 9 and reflectors 10a and 10b, an IDT electrode 11 and a reflector 12a are formed thereon. , 12b
Side-coupled dual mode SA
Construct a W filter. The frequency temperature characteristic of the laterally coupled dual mode SAW filter thus configured can be moved to a lower temperature side by the thickness Hs / λ of the silicon dioxide film 2, and the peak temperature Tp can be reduced. It can be set to a desired temperature. In the above, the case where the present invention is applied to a laterally coupled dual mode SAW filter has been described. However, it is needless to say that the present invention can be applied to other laterally coupled multimode SAW filters.
【0013】[0013]
【発明の効果】本発明は以上説明したように構成したの
で、四ほう酸リチウム圧電基板を用いて表面波デバイス
構成する場合に、二酸化シリコン膜の膜厚を適切に設定
することにより、その周波数温度特性を所望の温度範囲
内で最適になるように設定することが可能となり、表面
波デバイスの歩留まりを大幅に改善できるという優れた
効果を発揮する。According to the present invention, as described above, when a surface acoustic wave device is formed using a lithium tetraborate piezoelectric substrate, the frequency temperature of the silicon dioxide film can be appropriately set by setting the thickness of the silicon dioxide film. The characteristics can be set to be optimum within a desired temperature range, and an excellent effect that the yield of the surface acoustic wave device can be greatly improved is exhibited.
【図1】本発明に係るSAWデバイスの構成を示す図で
(a)は平面図、(b)は断面図である。FIG. 1 is a diagram showing a configuration of a SAW device according to the present invention, wherein (a) is a plan view and (b) is a cross-sectional view.
【図2】二酸化シリコン膜厚Hs/λと頂点温度偏差ΔTp
との関係を示す図である。FIG. 2 Silicon dioxide film thickness Hs / λ and peak temperature deviation ΔTp
FIG.
【図3】二酸化シリコン膜厚Hs/λとSAWデバイスの
Q値との関係を示す図である。FIG. 3 is a diagram showing a relationship between a silicon dioxide film thickness Hs / λ and a Q value of a SAW device.
【図4】本発明を縦結合1次−3次二重モードSAWフ
ィルタに適用したときの平面図である。FIG. 4 is a plan view when the present invention is applied to a longitudinally coupled first-order / third-order dual-mode SAW filter.
【図5】本発明を縦続型横結合二重モードSAWフィル
タに適用したときの平面図である。FIG. 5 is a plan view when the present invention is applied to a cascade-type laterally coupled dual mode SAW filter.
【符号の説明】 1・・圧電基板 2・・二酸化シリコン膜 3、5、6、7、9、11・・IDT電極 4a、4b、8a、8b、10a、10b、12a、1
2b・・グレーティング反射器 IN・・入力 OUT・・出力 Hs /λ・・二酸化シリコン膜厚 λ・・表面波の波長 Q・・Q値 ΔTp・・頂点温度偏差[Description of Signs] 1. Piezoelectric substrate 2 Silicon dioxide film 3, 5, 6, 7, 9, 11 IDT electrode 4a, 4b, 8a, 8b, 10a, 10b, 12a, 1
2b ・ ・ Grating reflector IN ・ ・ Input OUT ・ ・ Output Hs / λ ・ ・ Silicon dioxide film thickness λ ・ ・ Surface wave wavelength Q ・ ・ Q value ΔTp ・ ・ Vertex temperature deviation
Claims (3)
酸化シリコン膜を形成しその上に励起される表面波の伝
搬方向に沿って少なくとも1つのIDT電極と両側に反
射器を配置して構成する表面波共振子において、前記二
酸化シリコン膜の膜厚Hsと励起される表面波の波長λ
との比Hs/λを 5×10-4 ≦ Hs/λ ≦ 5×10-3 としたことを特徴とする弾性表面波デバイス。1. A structure in which a silicon dioxide film is formed on a main surface of a lithium tetraborate piezoelectric substrate, and at least one IDT electrode and reflectors are arranged on both sides along a propagation direction of a surface wave excited on the silicon dioxide film. In the surface acoustic wave resonator, the thickness Hs of the silicon dioxide film and the wavelength λ of the surface acoustic wave to be excited
A surface acoustic wave device, wherein the ratio Hs / λ of the surface acoustic wave is 5 × 10 −4 ≦ Hs / λ ≦ 5 × 10 −3 .
沿って近接配置し縦結合多重モード表面波フィルタとし
たことを特徴とする請求項1記載の弾性表面波デバイ
ス。2. The surface acoustic wave device according to claim 1, wherein a plurality of IDT electrodes are arranged close to each other along the propagation direction of the surface acoustic wave to form a longitudinally coupled multimode surface acoustic wave filter.
て構成する表面波共振子を表面波の伝搬方向と並行して
近接配置して横結合多重モード表面波フィルタとしたこ
とを特徴とする請求項1記載の弾性表面波デバイス。3. A transversely coupled multi-mode surface wave filter in which an IDT electrode and a surface acoustic wave resonator having reflectors arranged on both sides thereof are closely arranged in parallel with the propagation direction of the surface acoustic wave. The surface acoustic wave device according to claim 1.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10124123A JPH11308069A (en) | 1998-04-17 | 1998-04-17 | Surface acoustic wave device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10124123A JPH11308069A (en) | 1998-04-17 | 1998-04-17 | Surface acoustic wave device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH11308069A true JPH11308069A (en) | 1999-11-05 |
Family
ID=14877502
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP10124123A Withdrawn JPH11308069A (en) | 1998-04-17 | 1998-04-17 | Surface acoustic wave device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH11308069A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008109413A (en) * | 2006-10-25 | 2008-05-08 | Fujitsu Media Device Kk | Elastic wave device and filter |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5979622A (en) * | 1982-10-29 | 1984-05-08 | Toshiba Corp | Elastic surface wave element |
JPH0677331U (en) * | 1993-03-30 | 1994-10-28 | 京セラ株式会社 | Multimode surface acoustic wave filter |
JPH08153915A (en) * | 1994-11-30 | 1996-06-11 | Matsushita Electric Ind Co Ltd | Composite piezoelectric substrate and its manufacture |
JPH1065491A (en) * | 1996-08-14 | 1998-03-06 | Toyo Commun Equip Co Ltd | Idt excitation dual mode filter |
-
1998
- 1998-04-17 JP JP10124123A patent/JPH11308069A/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5979622A (en) * | 1982-10-29 | 1984-05-08 | Toshiba Corp | Elastic surface wave element |
JPH0677331U (en) * | 1993-03-30 | 1994-10-28 | 京セラ株式会社 | Multimode surface acoustic wave filter |
JPH08153915A (en) * | 1994-11-30 | 1996-06-11 | Matsushita Electric Ind Co Ltd | Composite piezoelectric substrate and its manufacture |
JPH1065491A (en) * | 1996-08-14 | 1998-03-06 | Toyo Commun Equip Co Ltd | Idt excitation dual mode filter |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008109413A (en) * | 2006-10-25 | 2008-05-08 | Fujitsu Media Device Kk | Elastic wave device and filter |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6415469B2 (en) | Acoustic wave resonator, filter and multiplexer, and method for manufacturing acoustic wave resonator | |
JP4100249B2 (en) | Surface acoustic wave device, communication device | |
JP2002100959A (en) | Surface acoustic wave device | |
JP3853252B2 (en) | Surface acoustic wave device | |
JPS61285814A (en) | Longitudinal double mode saw filter | |
US20100289379A1 (en) | Surface acoustic wave (saw) device | |
US6828879B2 (en) | Longitudinal coupled multiple mode surface acoustic wave filter | |
JP2019125856A (en) | Acoustic wave resonator, filter and multiplexer | |
US20220352871A1 (en) | Acoustic wave resonator, filter, and multiplexer | |
JP4251409B2 (en) | Surface acoustic wave filter | |
JP3890731B2 (en) | Vertically coupled multimode SAW filter | |
KR20200126420A (en) | Transducer structure for source suppression of SAW filter device | |
JPH1188100A (en) | Surface acoustic wave device | |
JP2002111443A (en) | Coupled surface acoustic wave filter | |
JPH06177703A (en) | Longitudinal triplex mode saw filter | |
JPH11308069A (en) | Surface acoustic wave device | |
JP3107392B2 (en) | Vertically coupled dual mode leaky SAW filter | |
JPH04113712A (en) | Longitudinal dual mode surface acoustic wave filter | |
JP2004260402A (en) | Surface acoustic wave device and communication device having it | |
JPH05129884A (en) | Multistage connection multiplex mode filter | |
JP2000091881A (en) | Cascade connecting double mode saw filter | |
JP3597483B2 (en) | Surface acoustic wave device | |
JPH04113711A (en) | Longitudinal dual mode surface acoustic wave filter | |
US20230117944A1 (en) | Bonded substrate and its manufacturing method | |
JPH11317643A (en) | Surface acoustic wave filter |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050216 |
|
A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070424 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070508 |
|
RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20070705 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20071016 |
|
A761 | Written withdrawal of application |
Free format text: JAPANESE INTERMEDIATE CODE: A761 Effective date: 20071113 |