JPS59210716A - Substrate for surface wave device - Google Patents

Abstract

PURPOSE:To obtain a high-precision elastic surface wave device by limiting the thickness of a film formed in a mismatching lattice array on a layered-structure substrate whose surface is covered with the thin film in the mismatching lattice array, to a specified range. CONSTITUTION:The elastic surface wave device 10 has the layered structure formed by vapor-depositing the thin film 13 in the mismatching lattice array on the substrate 12 to a 10Angstrom -0.03lambda (lambda: the wavelength of elastic surface wave) thickness. The center frequency f0 of a elastic surface wave filter is determined by f0=v/lambda (v: propagation speed of elestic surface wave), but variance in f0 due to variance in propagation speed (v) depending upon the substrate material is adjusted only by adjusting the film thickness of the thin film in the mismatching lattice array while the vapor-deposition time is varied. The relation between the film thickness and f0 is as shown by a curve 21. In this case, when the film thickness is <=10Angstrom , the thin film is not continuous and the reproducibility of characteristics is not obtained. When the film thickness is >=0.03lambda, on the other hand, the insertion loss increases as shown by a curve 22 and the practicability is not obtained. This structure is considered to has the relation between the f0 and the film thickness of the SiO2 film as shown by a curve 23. The curve 21 is never inverted when the thin film has a lattice in order.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、弾性表面波デバイス用の基板に関するもので
、特に高精度の弾性表面波デバイス用の基板に関してい
る。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a substrate for a surface acoustic wave device, and particularly to a substrate for a high precision surface acoustic wave device.

従来例の構成とその問題点 高精度の固体化フィルタ、共振器、遅延素子などに弾性
表面波デバイスが有用であるとされているか、弾性表面
波デバイスを生産すると使用材料の特性バラツキのため
、例えば弾性表面波フィルりの中心周波数のバラツキが
０．０５％以上である。Conventional configurations and their problems Surface acoustic wave devices are said to be useful for high-precision solid-state filters, resonators, delay elements, etc. When producing surface acoustic wave devices, due to variations in the characteristics of the materials used, For example, the variation in the center frequency of the surface acoustic wave fill is 0.05% or more.

一方、最近の情報機器では中心周波数の・くラツキは、
この値よりさらに１桁以上小さいことが要求されるため
、一般には選別という手段で生産されている。しかし、
この場合、より高精度のデノ（イスを大量に生産するこ
とは不可能であるため、高精度の弾性表面波デバイス用
材料の開発が強く要請されていた。本発明はこの要請に
応するものである。On the other hand, in recent information devices, the center frequency fluctuation is
Since it is required to be one order of magnitude smaller than this value, it is generally produced by means of sorting. but,
In this case, since it is impossible to mass-produce highly accurate denomination chairs, there has been a strong demand for the development of materials for highly accurate surface acoustic wave devices.The present invention satisfies this demand. It is something.

発明の目的 発明の構成 本発明は、基体表面を不整格子配列の薄膜で被覆された
層状構造基板の上記不整格子配列の薄膜の膜厚が１Ｑ八
から０．０３２（λ：層状構造基板における表面波の波
長）の範囲にあることを特徴とするもので、共振子、フ
ィルタ等の表面波デバイスに好適な表面波デバイス用基
板を提供するものである。Object of the Invention Constitution of the Invention The present invention provides a layered structure substrate in which the surface of the substrate is coated with a thin film with a mismatched lattice arrangement, and the thickness of the thin film with the mismatched lattice arrangement is 1Q8 to 0.032 (λ: the surface of the layered structure substrate). The present invention provides a surface wave device substrate suitable for surface wave devices such as resonators and filters.

実施例の説明 以下、図と実施例により本発明の詳細な説明する。Description of examples Hereinafter, the present invention will be explained in detail with reference to figures and examples.

第１図は、本発明の高精度の弾性表面波デバイス用基板
の要部構造を示す。すなわち、第１図１０は表面弾性波
デバイスの要部構造を示すもので、弾性表面波１１が伝
搬する基板１２の上に、不整格子配列の薄膜１３を、厚
さ１０八から０．ｏ３λ（）：弾性表面波の波長）の範
囲で蒸着した層状構造を有している。FIG. 1 shows the main structure of a high-precision surface acoustic wave device substrate of the present invention. That is, FIG. 10 shows the main structure of a surface acoustic wave device, in which a thin film 13 with a mismatched lattice arrangement is formed on a substrate 12 on which a surface acoustic wave 11 propagates, with a thickness ranging from 10.8 to 0.80 cm. It has a layered structure deposited in the range o3λ(): wavelength of surface acoustic waves).

すなわち、通常弾性表面波デバイスの周波数特性例えば
弾性表面波フィルタの中心周波数ｆ。は、ｆｏ−ｖ／λ
（■：弾性表面波の伝搬速度）の関係で決する。この場
合、λは１例えば弾性表面波励振用のインターディジタ
ル電極の幾可学的寸法で決まり、その設計値の寸法に加
工することは容易である。したかって、この種のデバイ
スを製造するときに問題になるのは、弾性表面波の伝搬
速度Ｖの基板材料によるバラツキに起因したｆ。のバラ
ツキである。ｆｏのバラツキは基板材料の物性定数例え
ばヤング率、密度、ボアノン比などのバラツキに起因し
たり、あるいは単結晶基板では弾性表面波の伝搬方向の
設定のバラツキなども加わったりして複雑である。した
がって、これらのバラツキを減らすことは通常の技術で
は容易ではない。That is, the frequency characteristics of a normal surface acoustic wave device, for example, the center frequency f of a surface acoustic wave filter. is fo-v/λ
It is determined by the relationship (■: propagation speed of surface acoustic waves). In this case, λ is determined by, for example, the geometric dimensions of an interdigital electrode for excitation of surface acoustic waves, and it is easy to process the dimension to the designed value. Therefore, when manufacturing this type of device, a problem arises in f due to variations in the propagation velocity V of the surface acoustic wave depending on the substrate material. This is the variation in The variations in fo are complicated because they are caused by variations in the physical constants of the substrate material, such as Young's modulus, density, and Boannon ratio, and in the case of single crystal substrates, variations in the setting of the propagation direction of surface acoustic waves are also added. Therefore, it is not easy to reduce these variations using normal techniques.

一方２本発明は、従来のｆ。のバラツキに関して、１０
０八程度の薄い薄膜でかつ結晶化の進んでいない不整格
子配列した薄膜アモルファス構造で、この種の薄膜は冷
却基板上に例えば蒸着プロセスで薄膜を形成するとき、
その薄膜の成長過程でしばしば見られる。この薄膜は島
状構造の薄膜が層状に積層されて、その状態が凍結され
た構造を示す。）を、弾性表面波の伝搬路上に例えば室
温程度に冷してスパッタ蒸着すると、蒸着時間を変えて
上記不整格子配列した薄膜の膜厚を調整するだけで容易
にｆ。を調整しうるという本発明者らの発見に基づくも
のである。第２図に、具体的な実施例を示す。水晶基板
上に形成した弾性表面波フィルタの弾性表面波の伝搬路
に、スパッタ法でＳｉＣ２の不整路に配列した薄膜を形
成した時の膜厚とｆ。との関係を曲線２１に示す。曲線
２１は、ｆｏの変化が膜厚により負から正に変化するこ
とを示すとともに、この変化を用いると膜厚によりｆ。On the other hand, two of the present inventions are based on the conventional f. Regarding the variation of 10
This type of thin film has an amorphous structure with a mismatched lattice arrangement, which is a thin film of about 0.08 in thickness and has not progressed in crystallization.
It is often seen during the growth process of the thin film. This thin film exhibits a structure in which thin films having an island-like structure are laminated in layers and the state thereof is frozen. ) is sputter-deposited on the propagation path of a surface acoustic wave after cooling it to room temperature, for example, and then f can be easily obtained by simply adjusting the thickness of the misaligned thin film by changing the deposition time. This is based on the discovery by the present inventors that it is possible to adjust the FIG. 2 shows a concrete example. Film thickness and f when a thin film of SiC2 arranged in irregular paths is formed by sputtering on the propagation path of the surface acoustic wave of a surface acoustic wave filter formed on a quartz substrate. The relationship with is shown in curve 21. Curve 21 shows that the change in fo changes from negative to positive depending on the film thickness, and when this change is used, f changes depending on the film thickness.

を正負の方向に任意に調整できることを示すっこの場合
、膜厚が薄すぎて、例えば蒸着され／ｃ、１．７膜の厚
さが例えば１０八以下になると蒸着され／ζ薄膜が連続
膜にならず特性の再現性がない。In this case, if the film thickness is too thin, for example, it will be deposited /c, and if the thickness of the 1.7 film becomes, for example, 108 or less, it will be deposited /ζ The thin film will be a continuous film. The characteristics are not reproducible.

１に逆に膜厚が厚すぎて例えば膜厚が０．０３λ（λ：
表面波の波長）以上になると曲線２２が示すごとく挿入
損失が通常の回路設計に問題になる１ｄＢ以上に増加し
、実用性に欠く。なお、この構造では、ｆｏとＳｔ○２
薄膜の膜厚との関係は、理論的には第２図曲線２３のご
とく単調にｆ。が増加すると考えられていた。したがっ
て、第２図曲線２１でのｆｏの負から正への転換（極小
点の存在）は、通常の格子の整った薄膜では見られない
もので、本発明にかかる不整格子配列の薄膜の特徴でも
ある。On the contrary, the film thickness is too thick, for example, the film thickness is 0.03λ (λ:
As shown by curve 22, if the insertion loss exceeds 1 dB (the wavelength of the surface wave), the insertion loss increases to more than 1 dB, which is a problem in ordinary circuit design, and is therefore impractical. In addition, in this structure, fo and St○2
Theoretically, the relationship with the thickness of the thin film is f, as shown by curve 23 in FIG. was thought to increase. Therefore, the transition of fo from negative to positive (existence of a minimum point) in curve 21 in FIG. There is also.

なお、不整格子配列の薄膜１３の膜厚によるｆ。Note that f is determined by the thickness of the thin film 13 having an irregular lattice arrangement.

の特異な変化２１は、上述したように、この種の薄膜の
通常のバルク材料との物性の差を示しており、これは−
１′た第３図曲線３１に示すような屈折率の膜厚による
特異な変化からも推察される。この曲線３１によれば、
薄い薄膜ではバルクより屈折率が少さく、一定膜厚にな
るとバルク値に近づくことがわかる。As mentioned above, the peculiar change in 21 indicates the difference in the physical properties of this type of thin film from that of ordinary bulk materials, and this is -
This can also be inferred from the peculiar change in refractive index depending on the film thickness, as shown by curve 31 in FIG. According to this curve 31,
It can be seen that the refractive index of a thin film is lower than that of the bulk, and approaches the bulk value when the film thickness becomes constant.

また、この種の層状構成において１、不整格子配列の薄
膜の組成は、化学的に安定で、かつ弾性表面波の伝搬に
大きなさまたげにならなければよく、上述した５１０２
のような酸化物以外に、窒化シリコン、窒化アルミニウ
ムのような窒化物、シリコンカーバイト、ボロンカーバ
イトなどの炭化物。In addition, in this type of layered structure, 1. the composition of the thin film with mismatched lattice arrangement should be chemically stable and not significantly hinder the propagation of surface acoustic waves;
In addition to oxides such as, nitrides such as silicon nitride and aluminum nitride, and carbides such as silicon carbide and boron carbide.

ボロン、ボロン化シリコンなどの硼化物、　Ａ　ｓ　２
Ｓｅ３などのカルコゲ−ナイトなども有効であることを
本発明者らは確認した。ただ、薄膜１３の膜厚により、
第２図曲線２１のとと〈ｆｏに正負の特異な変化特性を
得るには、例えば、基板１２の音速が薄膜１３の音速の
バルク値と薄膜１３の不整格子配列秋態の場合の値の間
の値である必要があり、このためには例えば基板１２が
水晶単結晶であるときは、例えば水晶と化学組成が同一
のＳ　ｚ　０２の薄膜１３を用いる。なお、ガラス材料
を例えば基板１２に用いると、広範囲の音速の基板が得
られるから、この種の層状構造の基板として有効であこ
のような層状構造の基板は、各種の弾性表面波デバイス
の形成に有効であり、例えば弾性表面波フィルタ、遅延
素子２発振子などに広範囲に実用されることを本発明者
らは確認した。Borides such as boron and silicon boronide, A s 2
The present inventors have confirmed that chalcogenites such as Se3 are also effective. However, depending on the thickness of the thin film 13,
In order to obtain unique positive and negative change characteristics in the curve 21 and fo in FIG. For this purpose, for example, when the substrate 12 is a single crystal of quartz, a thin film 13 of S z 02 having the same chemical composition as quartz is used. If a glass material is used for the substrate 12, for example, a substrate with a wide range of sound velocities can be obtained, so it is effective as a substrate with this kind of layered structure. The present inventors have confirmed that the present invention is effective for a wide range of practical applications, such as surface acoustic wave filters and dual delay element oscillators.

第４図４０は基板１２に上述した例のごとく圧電結晶を
用い、一対の送受信用の弾性表面波励振用櫛型電極より
なるインターディジタルトランスデユーサ（ＩＤＴ）４
１を設けた所謂４端子構造の弾性裏面波フィルタである
が、ここではＩＤＴ部に７：、り膜１３を設けている。FIG. 4 40 shows an interdigital transducer (IDT) 4 that uses a piezoelectric crystal as the substrate 12 as in the example described above, and has a pair of comb-shaped electrodes for excitation of surface acoustic waves for transmission and reception.
This is a back acoustic wave filter having a so-called four-terminal structure in which 7 and 13 are provided in the IDT section.

基板１２に用いる圧電体としては、水晶以外にＬｉＮｂ
Ｏ３，ＬｉＴａｏｓ。In addition to crystal, LiNb can be used as the piezoelectric material used for the substrate 12.
O3, LiTaos.

ＣｄＳ、Ｚｎ○、Ａ６Ｎ、ＧａＡｓ、ｐＺＴ（ＰｂＺｒ
、Ｔｉ１−ｘＯ）などがよく、この場合、例えば水晶は
超高安定用、　Ｌ　Ｉ　Ｎ　ｂｏ３．　ｐ　Ｚ　Ｔは高
結合用（広帯域用）　、　ＬｉＴａｏｓ　、　Ｚ　ｎ　
Ｏは高安定用の弾性表面波デバイスの形成に有効である
。また、Ｇ　ａ　Ａ　ｓ結晶は、Ｇ　ａ　Ａ　ｓ半導体
素子と弾性表面波デノくイスとのモノリシック化に有効
である。CdS, Zn○, A6N, GaAs, pZT (PbZr
, Ti1-xO), etc. In this case, for example, the crystal is for ultra-high stability, L I N bo3. p Z T is for high coupling (broadband), LiTaos, Z n
O is effective in forming a highly stable surface acoustic wave device. Further, the GaAs crystal is effective for monolithically forming a GaAs semiconductor element and a surface acoustic wave device.

さらに、これらの圧電性基板に適した不整格子配列の薄
膜材料としては、水晶では５１０２　、　Ｌ　ｌＮｂ０
　ではＬｉＮｂ０　　ＬｉＴａ０　　ではＬ　ｚ　Ｔ　
ａ　Ｏｓの３　　　　　　　　３、　　　　　３ ごとく基板と同一組成が有用であることを本発明者らは
確認した。Furthermore, as a thin film material with mismatched lattice arrangement suitable for these piezoelectric substrates, 5102 for quartz and L lNb0
Then, LiNb0 LiTa0 then L z T
The present inventors have confirmed that the same composition as the substrate, such as 3 3, 3 of a Os, is useful.

第５図６０は、基板１２を非圧電性基板１２１上に圧電
性薄膜１２２を蒸着した積層構造で構成した弾性表面波
遅延線の構造を示す。この場合、非圧電性基板１２１は
弾性表面波の伝搬速度の温度変化が小さい例えば零温度
係数ガラスを用い、圧電性薄膜１２２には例えばＣ軸配
向したＺｎＯ圧電薄膜を用いる。また、遅延線の特性周
波数の子配列の薄膜１３をつづいて蒸着し、最後に送受
信用のＩＤＴ部１を形成する。この基板１２１として、
ガラス以外にサファイア、スピネル、マグネシアのよう
な絶縁体あるいはＳｔのような半導体を用いると、これ
らの基板上に良質の圧電性薄膜が形成され、弾性表面波
デバイスと半導体、光デバイスなどとのモノリシック化
にも有効である。FIG. 560 shows the structure of a surface acoustic wave delay line in which the substrate 12 has a laminated structure in which a piezoelectric thin film 122 is deposited on a non-piezoelectric substrate 121. In this case, the non-piezoelectric substrate 121 is made of, for example, zero temperature coefficient glass whose propagation velocity of surface acoustic waves changes little with temperature, and the piezoelectric thin film 122 is made of, for example, a C-axis oriented ZnO piezoelectric thin film. Further, a thin film 13 having a sub-array of characteristic frequencies of the delay line is successively deposited, and finally, an IDT section 1 for transmitting and receiving is formed. As this substrate 121,
When insulators such as sapphire, spinel, and magnesia, or semiconductors such as St are used in addition to glass, high-quality piezoelectric thin films are formed on these substrates, allowing monolithic integration of surface acoustic wave devices, semiconductors, optical devices, etc. It is also effective for

さらに、本発明者らはこの種の層状基板を用いると、第
６図６０に示すような共振子の形成にも有効であること
を確認した。この共振子は、例えば基板１２にＳＴカッ
ト水晶を用い、中央部に一対のＩＤＴ６１、端部にグレ
ーテング構造の反射器６２を設ける。この場合、主成分
が５１０２の不整格子配列の薄膜１３を、反射器６２の
上部に積層し、この薄膜１３の膜厚を所望の値にして共
振子の中心周波数ｆ。を所望の値にする。　この例以外
に、例えば非圧電性基板１２を用いるときは、中央部の
ＩＤＴは薄膜圧電体を積層した所謂薄膜トランステユー
ザの構造を用いる。また、反射器は非圧電性基板上に形
成する場合は、上述したグレーテング構造を用いるが、
圧電性基板の場合は反＃Ｊ器はグレーテング構造以外に
例えばへ４蒸着膜からなるインターデジタル電極でも形
成しうるから、この場合、上記薄膜１３は、インターデ
ジタル電極の上に形成する。当然のことながら、これら
の反射器は、薄膜１３を最適の薄膜に蒸着してから、こ
の薄膜１３の±に形成してもよい。Furthermore, the present inventors have confirmed that the use of this type of layered substrate is effective in forming a resonator as shown in FIG. 660. This resonator uses, for example, an ST-cut crystal for the substrate 12, and has a pair of IDTs 61 at the center and a reflector 62 with a grating structure at the ends. In this case, a thin film 13 having a mismatched lattice arrangement with a main component of 5102 is laminated on top of the reflector 62, and the film thickness of this thin film 13 is set to a desired value so that the center frequency f of the resonator is set. to the desired value. In addition to this example, when using the non-piezoelectric substrate 12, for example, the central IDT uses a so-called thin-film transformer structure in which thin-film piezoelectric materials are laminated. In addition, when the reflector is formed on a non-piezoelectric substrate, the grating structure described above is used.
In the case of a piezoelectric substrate, in addition to the grating structure, the anti-#J device can also be formed with an interdigital electrode made of, for example, a vapor-deposited film. In this case, the thin film 13 is formed on the interdigital electrode. Of course, these reflectors may be formed on either side of the thin film 13 after the thin film 13 has been deposited to a suitable thin film.

ここで、本発明をよりよく理解されるために、より具体
的な実施例を説明する。More specific examples will now be described in order to better understand the present invention.

実施例　（１） ＳＴカット水晶１２０表面にＡｌ蒸着膜からなる櫛型電
極対（線巾０．９μｍ、対数３００．電極膜厚５００人
）を形成した。この電極付を入出力電極とした弾性表面
波フィルタの中心周波数ｆ０は８４８．２ＭＨ２であっ
たが、所望の周波数０．２ＭＨｚずれていた。Example (1) A comb-shaped electrode pair (wire width 0.9 μm, number of logarithms 300, electrode film thickness 500) made of an Al vapor-deposited film was formed on the surface of an ST-cut crystal 120. The center frequency f0 of the surface acoustic wave filter with this electrode as the input/output electrode was 848.2 MH2, but it was deviated from the desired frequency by 0.2 MHz.

つづいて、マグネトロンバッタ装置で、石英ターゲット
をアルゴンガス中でスパッタし、伝搬路に１分間主成分
がＳｉｏ２の薄膜１３を形成した。Subsequently, a quartz target was sputtered in argon gas using a magnetron batter apparatus, and a thin film 13 whose main component was Sio2 was formed on the propagation path for 1 minute.

蒸着中素子の温度は３０’Ｃに保持した。その結果、中
心周波数は８４８　ＭＨｚ　（所望の値）を得た。薄膜
１３の厚さは１００八であった。ここで、膜厚組成がこ
れと同一の１００人の薄膜１３をあらかじめ蒸着した層
状構造の本発明の基板を形成し、この上に同様のプロセ
スで弾性表面波フィルタを形成すると、ｆｏの製造バラ
ツキは量産時で±５０ＫＨｚ以下であった。The temperature of the device was maintained at 30'C during the deposition. As a result, a center frequency of 848 MHz (desired value) was obtained. The thickness of the thin film 13 was 1,008 mm. Here, if a substrate of the present invention with a layered structure is formed on which a 100-layer thin film 13 having the same film thickness and composition as this is pre-deposited, and a surface acoustic wave filter is formed thereon by a similar process, manufacturing variations in fo was less than ±50KHz during mass production.

実施例　（２） （０００１）ＺｎＯ薄膜／ガラス基板の多層構造基板１
２０表面にＡｌ蒸着膜からなる櫛型電極対（線１１５．
４７ｚｍ　、対数２０．電極膜厚１５００八）を形成し
た。この電極付を入出力電極とした弾性表面波フィルタ
の中心周波数ｆ。は１４５　、０５ＭＨｚてあっ／でか
、所望の周波数０　、０５　ＭＨｚずれていた。Example (2) (0001) Multilayer structure substrate 1 of ZnO thin film/glass substrate
A pair of comb-shaped electrodes (line 115.
47zm, logarithm 20. An electrode film thickness of 1500 mm) was formed. The center frequency f of a surface acoustic wave filter with this electrode as an input/output electrode. The frequency was 145 MHz, 0.05 MHz, and the desired frequency was off by 0.05 MHz.

つづいて、マグネトロンスパッタ装置で石英ターゲット
をアルゴンガス中でスパッタし、伝搬路に１分間主成分
が８１０２の薄膜１３を形成した。蒸着中素子の湿度は
３０℃に保持した。その結果、中心周波数は１４５　Ｍ
Ｈｚ　（所望の値）を得た。薄膜１３の厚さは３００八
であった。ここで膜厚組成がこれと同一の３００人の薄
膜１３をあらかじめ蒸着した層状構造の本発明の基板を
形成し、この上に同様のプロセスで弾性表面波フィルタ
を形成すると、ｆｏの製造バラツキは量産時で±１０Ｋ
Ｈｚ以下であった。Subsequently, a quartz target was sputtered in argon gas using a magnetron sputtering device to form a thin film 13 whose main component was 8102 on the propagation path for 1 minute. The humidity of the device was maintained at 30° C. during the vapor deposition. As a result, the center frequency is 145 M
Hz (desired value) was obtained. The thickness of the thin film 13 was 300 mm. Here, if a substrate of the present invention with a layered structure is formed on which a 300-layer thin film 13 having the same film thickness and composition as this is pre-deposited, and a surface acoustic wave filter is formed on this by a similar process, manufacturing variations in fo will be reduced. ±10K during mass production
It was below Hz.

実施例　（３） ＳＴカット水晶１２の表面の中央部にＡ６蒸着膜からな
る櫛型電極対（線巾１．２７１ｍ、対数３０゜電極膜Ｎ
５００人）と、これらの電極付の両端部にグレーテング
反射器（線巾１，２μｍ、グレーテング数２ｏＯ）を設
けて弾性表面波共振器を形成した。その結果、共振周波
数ばｅ　７４．２ＭＨｚであったが、所望の周波数より
０．２　ＭＨｚずれていた。Example (3) A comb-shaped electrode pair (line width 1.271 m, logarithm 30° electrode film N
500 persons) and grating reflectors (line width 1.2 μm, number of gratings 200) were provided at both ends of these electrodes to form a surface acoustic wave resonator. As a result, the resonant frequency was 74.2 MHz, which was deviated from the desired frequency by 0.2 MHz.

つづいて、マグネトロンスパッタ装置で、石英ターケソ
トヲアルゴンガス中でスパッタし、グレーテング上に１
分間主成分が８１０２の薄膜１３を形成した。蒸着中素
子の温度は３０℃に保持した。。Next, the quartz film was sputtered in argon gas using a magnetron sputtering device, and one layer was sputtered onto the grating.
A thin film 13 having a main component of 8102 was formed in minutes. The temperature of the device was maintained at 30° C. during the deposition. .

その結果、共振周波数は６７４ＭＨｚ　（所望の値）を
得た。薄膜１３の厚さは１００八であった。ここで、膜
厚がこれと同一の１００への主成分がＳｉｏ２の薄膜１
３をあらかじめ蒸着した層状構造の本発明の基板を形成
し、この上に同様のプロセスで弾性表面波共振子を形成
すると、共振周波数の製造時のバラツキは量産時で±６
０　ＫＨｚ以下であった。As a result, a resonant frequency of 674 MHz (desired value) was obtained. The thickness of the thin film 13 was 1,008 mm. Here, a thin film 1 whose main component is Sio2 is added to 100 with the same film thickness.
3 is deposited in advance, and a surface acoustic wave resonator is formed thereon by a similar process, the manufacturing variation in resonance frequency is reduced to ±6 during mass production.
It was below 0 KHz.

発明の効果 以上の説明からも明らかなごとく、本発明の弾性表面彼
テ・・イス用基板を用いると、高精度の弾性表面波デバ
イスか容易に生産できる特長がある。Effects of the Invention As is clear from the above explanation, the use of the substrate for an elastic surface acoustic wave chair of the present invention has the advantage that a highly accurate surface acoustic wave device can be easily produced.

この場合、弾性表面波デバイスの伝搬路面への不整格子
配列の薄膜の積層構造が特徴である。不整格子配列のン
′！９膜は、本実施例ではスパッタ蒸着で形成する方法
について述べたが、必ずしもスパッタ蒸着法に依る必要
はなく、蒸着された薄膜の格子が乱れておりさえすれば
よい。イオンビームスバッタ、電子ビーム蒸着、化学的
気相成長（ＣＶＤ）、プラズマＣＶＤも実用し得るので
、製造上技術的な問題はない。なお従来弾性表面波伝搬
面に、異種月利を積層することは一般に弾性表面波の伝
搬損失が増えたり、基板に歪の発生のためデバイスの信
頼性が下がるといわれて好ましくないとされていたが、
本発明のごとく特異な構造の薄膜とその膜厚範囲を選←
べば、これらを弾性表面波デバイスの伝搬面に積層して
も、弾性表面波特性に悪影響しないばかりか例えばシリ
コンカーバイト薄膜では破水性を示すためデバイスの耐
湿性の向上にもつながる。−！だ、本発明の効果は、実
施例に述べたフィルタあるいは遅延素子２発振子に限定
されたものではなく、これ以外にコンボルバ−をはじめ
、あらゆる種類の弾性表面波デバイス、さらには音響光
学デバイスの形成に本発明は有効であるから、その工業
的価値は高い。This case is characterized by a laminated structure of thin films arranged in a mismatched lattice on the propagation path surface of the surface acoustic wave device. Irregular lattice array n′! In this embodiment, the method of forming the 9th film by sputter deposition has been described, but it is not necessarily necessary to rely on the sputter deposition method, and it is sufficient that the lattice of the deposited thin film is disordered. Since ion beam scattering, electron beam evaporation, chemical vapor deposition (CVD), and plasma CVD can also be used, there are no technical problems in manufacturing. Conventionally, it has been considered undesirable to stack different types of materials on the surface acoustic wave propagation surface, as it is said to increase the propagation loss of the surface acoustic waves and reduce the reliability of the device due to the generation of distortion in the substrate. but,
Select a thin film with a unique structure like the one of the present invention and its film thickness range←
Even if they are laminated on the propagation surface of a surface acoustic wave device, not only will this not have any negative effect on the surface acoustic wave characteristics, but silicon carbide thin films, for example, exhibit water rupture properties, which will lead to improved moisture resistance of the device. -! However, the effects of the present invention are not limited to the filter or the two-delay element oscillator described in the embodiments, but are also applicable to convolvers, all kinds of surface acoustic wave devices, and even acousto-optic devices. Since the present invention is effective for formation, its industrial value is high.

【図面の簡単な説明】[Brief explanation of drawings]

えい、Ｄ４１ヶ、。、Ｌ楚へ、□いえ。 いた弾性表面波デバイスの要部構造図である。 １２・・・・・・基板、１３・・・・・・不整格子配列
の薄膜、４１・・・・・・弾性表面波励振用櫛型電極、
６２・・・・・反射器、１２１・・・・・・非圧電性基
板、１２２・・・・・・圧電性薄膜。 代理人の氏名　弁理士　中　尾　敏　男　ほか１名第１
図 第２図 第３図 Ｒ莫屑（う皮五す七う 第４図 Ｒ肩（／ｉ〕Yes, 41 D. , to L Chu, □No. FIG. 2 is a structural diagram of main parts of a surface acoustic wave device. 12... Substrate, 13... Thin film with mismatched lattice arrangement, 41... Comb-shaped electrode for surface acoustic wave excitation,
62... Reflector, 121... Non-piezoelectric substrate, 122... Piezoelectric thin film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure R

Claims (12)

【特許請求の範囲】[Claims] （１）基体表面を不整格子配列の薄膜で被覆された層状
構造基板の上記不整格子配列の薄膜の膜厚が１０人から
０．０３λ（λ：層状構造基板における表面波の波長〕
の範囲にあることを特徴とする表面波デバイス用基板。(1) In a layered structure substrate whose substrate surface is coated with a thin film with an irregular lattice arrangement, the thickness of the thin film with an irregular lattice arrangement is 0.03λ (λ: wavelength of surface wave in the layered structure substrate) from 10 people.
A surface wave device substrate characterized by being in the range of . （２）不整格子配列の薄膜が、酸化物、窒化物、炭化物
、硼化物、カルコゲケナイトのうちの少なくとも一種か
らなることを特徴とする特許請求の範囲第１項記載の表
面波デバイス用基板。(2) The substrate for a surface wave device according to claim 1, wherein the thin film with a mismatched lattice arrangement is made of at least one of oxides, nitrides, carbides, borides, and chalcogenites. （３）不整格子配列の薄膜が酸化シリコンであることを
！＃Ｉ徴とする特許請求の範囲第１項記載の表面波デバ
イス用基板。(3) The thin film with mismatched lattice arrangement is silicon oxide! The surface wave device substrate according to claim 1, which has the #I feature. （４）基体か圧電体であることを特徴とする特許請求の
範囲第１項記載の表面波デバイス用基板。(4) The substrate for a surface wave device according to claim 1, wherein the substrate is a piezoelectric material. （５）基体。が圧電性薄膜で表面を被覆された半導体あ
るいは絶縁体であることを特徴とする特許請求の範囲第
１項記載の表面波デバイス用基板。(5) Substrate. 2. The surface wave device substrate according to claim 1, wherein the substrate is a semiconductor or an insulator whose surface is coated with a piezoelectric thin film. （６）圧電体が水晶、ＬｉＮｂ０　　ＬｉＴａＯ３，Ｚ
ｎ０゜３ア ＡＩＮ、ＧａＡｓ、　　あるいはｐ　Ｚ　Ｔ　（ＰｂＺ
ｒｘＴｉｌ−ｘ○３）であることを特徴とする特許請求
の範囲第４項記載の表面波デバイス用基板。(6) Piezoelectric body is crystal, LiNb0 LiTaO3,Z
n0゜3aAIN, GaAs, or p Z T (PbZ
5. The surface wave device substrate according to claim 4, wherein the substrate is rxTil-x○3). （７）圧電性薄膜がＺｎＯ，ＡｌＮ、ＣｄＳあるいはｐ
ｚＴ（Ｐ　ｂ　Ｚ　ｒ　ｘＴ　１１−ｘ○３）であるこ
とを特徴とする特許請求の範囲第５項記載の表面波デバ
イス用基板。(7) The piezoelectric thin film is ZnO, AlN, CdS or p
6. The surface wave device substrate according to claim 5, which is zT (P b Z r xT 11-x○3). （８）基体がガラス、サファイア、スピネル、マグネシ
ャあるいはＳｉで構成されたことを特徴とする特許ｍ’
ｌＪ求の範囲第１項記載の表面波デバイス用基板。(8) Patent m' characterized in that the substrate is made of glass, sapphire, spinel, magnesia, or Si.
The substrate for a surface wave device according to item 1, wherein the range of lJ is desired. （９）不整格子配列の薄膜と基体の構成材料組成が同一
であることを特徴とする特許請求の範囲第１項記載の表
面波デバイス用基板。(9) The substrate for a surface acoustic wave device according to claim 1, wherein the thin film having the mismatched lattice arrangement and the base material have the same constituent material composition. （１０）不整格子配列の薄膜が酸化シリコンでかつ基体
が水晶であることを特徴とする特許請求の範囲第９項記
載の表面波デバイス用基板。(10) The substrate for a surface acoustic wave device according to claim 9, wherein the misaligned thin film is made of silicon oxide and the substrate is made of quartz. （１１）基板上に共振子用の弾性表面波反射器を設けた
ことを特徴とする特許請求の範囲第１項に記載の表面波
デバイス用基板。(11) The substrate for a surface acoustic wave device according to claim 1, further comprising a surface acoustic wave reflector for a resonator provided on the substrate. （１２）基板」二にフィルタ用弾性表面波励振用櫛型電
極を設けたことを特徴とする特許請求の範囲第１項に記
載の表面波デバイス用基板。(12) The substrate for a surface acoustic wave device according to claim 1, characterized in that a comb-shaped electrode for excitation of a surface acoustic wave for a filter is provided on the substrate.