JPS595722A - Electrode structure of thin film of zinc oxide - Google Patents
Electrode structure of thin film of zinc oxideInfo
- Publication number
- JPS595722A JPS595722A JP11444782A JP11444782A JPS595722A JP S595722 A JPS595722 A JP S595722A JP 11444782 A JP11444782 A JP 11444782A JP 11444782 A JP11444782 A JP 11444782A JP S595722 A JPS595722 A JP S595722A
- Authority
- JP
- Japan
- Prior art keywords
- zinc oxide
- oxide film
- electrode structure
- thin film
- electrode
- 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.)
- Granted
Links
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 title claims abstract description 86
- 239000011787 zinc oxide Substances 0.000 title claims abstract description 43
- 239000010409 thin film Substances 0.000 title claims description 31
- 238000000034 method Methods 0.000 abstract description 7
- 238000010894 electron beam technology Methods 0.000 abstract description 5
- 238000009792 diffusion process Methods 0.000 abstract description 4
- 238000004544 sputter deposition Methods 0.000 abstract description 4
- 238000010897 surface acoustic wave method Methods 0.000 abstract description 2
- 229910000942 Elinvar Inorganic materials 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 13
- 239000000758 substrate Substances 0.000 description 6
- 230000010355 oscillation Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000005452 bending Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/131—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials consisting of a multilayered structure
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は安定な特性を示す酸化亜鉛薄膜の電極構造に
関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode structure of a zinc oxide thin film exhibiting stable characteristics.
酸化亜鉛薄膜は弾性表面波装置、音叉振動子、音片振動
子などの圧電体として使用されている。Zinc oxide thin films are used as piezoelectric materials in surface acoustic wave devices, tuning fork vibrators, vibrator elements, etc.
この酸化亜鉛薄膜の使用例を音叉振動子にもとづいて説
明する。An example of the use of this zinc oxide thin film will be explained based on a tuning fork vibrator.
第１図は音叉振動子の一例を示す側面図である８図にお
いて、１は音叉振動子の本体、２．３はこの本体１の脚
部を示し、脚部２．３の側壁２ａ 。FIG. 1 is a side view showing an example of a tuning fork vibrator. In FIG. 8, 1 is a main body of a tuning fork vibrator, 2.3 is a leg portion of this main body 1, and a side wall 2a of the leg portion 2.3.
３ａには酸化亜鉛源ＩＩ ４．５が形成されている。Zinc oxide source II 4.5 is formed in 3a.
この酸化亜鉛薄膜４．５は真空蒸着法、スパッタリング
法、イオンブレーティング法などにより形成される。６
．７は酸化亜鉛薄膜４．５の上に形成されたへρ電極を
示す。This zinc oxide thin film 4.5 is formed by vacuum evaporation, sputtering, ion blasting, or the like. 6
．． 7 shows a ρ electrode formed on the zinc oxide thin film 4.5.
このＡｊ２電極６．７は安価でボンディングができるこ
とから選ばれたもので、電子ビーム蒸着法などにより３
０００〜１００００Ａの膜厚の範囲で形成される。This Aj2 electrode 6.7 was chosen because it is cheap and can be bonded, and it is made by electron beam evaporation method etc.
It is formed with a film thickness in the range of 000 to 10000A.
しかしながら、上記したような酸化亜鉛薄膜の電極構造
では次のような欠点が見られる。つまり、へρ電極その
ものが高い親和性を示すため、酸化亜鉛薄膜中にＡβが
拡散し、電気的特性が劣化するという欠点がある。すな
わち、２価の半導体である酸化亜鉛に３価であるＡβが
拡散することによって酸化亜鉛１膜の電気的特性、たと
えば振動周波数を大きく変化させるという現象が認めら
れた。また高温負荷寿命試験を行うと、さらに上記した
現象が促進され、電気的特性の劣化が一層大きなものと
なった。However, the electrode structure of the zinc oxide thin film as described above has the following drawbacks. That is, since the ρ electrode itself exhibits a high affinity, there is a drawback that Aβ diffuses into the zinc oxide thin film and the electrical characteristics deteriorate. That is, a phenomenon was observed in which the electrical properties of the zinc oxide film, such as the vibration frequency, were significantly changed due to the diffusion of trivalent Aβ into zinc oxide, which is a divalent semiconductor. Furthermore, when a high-temperature load life test was conducted, the above-mentioned phenomenon was further accelerated, and the deterioration of the electrical characteristics became even more significant.
したがって、酸化亜鉛薄膜を形成するに当っては、電極
を含めた構成全体について考慮する必要があり、従来の
電極構成にさらに改良を施さなければならなかった。Therefore, when forming a zinc oxide thin film, it is necessary to consider the entire structure including the electrode, and it is necessary to further improve the conventional electrode structure.
こ゛の発明はかかる背景からなされたものであり、安定
な特性を示す酸化亜鉛薄膜の電極構造を提供することを
目的どする。The present invention was made against this background, and an object thereof is to provide an electrode structure of a zinc oxide thin film exhibiting stable characteristics.
以下この発明を実施例にもとづいて詳細に説明する。The present invention will be described in detail below based on examples.
第２図はこの発明にかかる酸化亜鉛薄膜の電極構造を音
叉振動子に適用した例を示す側面図である。FIG. 2 is a side view showing an example in which the zinc oxide thin film electrode structure according to the present invention is applied to a tuning fork vibrator.
１１はエリンバなどからなる金属音叉、１２は酸化亜鉛
薄膜、１３は Ｔａ一層、１４は電極である。このうち
Ｔａ・層１３は電子ビーム法、スパッタリング法、イ
オンビーム法、抵抗加熱蒸着法などによって形成される
。11 is a metal tuning fork made of Erimba or the like, 12 is a zinc oxide thin film, 13 is a single layer of Ta, and 14 is an electrode. Of these, the Ta layer 13 is formed by an electron beam method, a sputtering method, an ion beam method, a resistance heating vapor deposition method, or the like.
第３図は屈曲振動モードの音片振動子にこの発明にかか
る酸化亜鉛薄膜の電極構造を適用した例を示した斜視図
である。FIG. 3 is a perspective view showing an example in which the electrode structure of the zinc oxide thin film according to the present invention is applied to a sound element vibrator in a bending vibration mode.
図において、２１は振動子本体を示し、振動子２２とこ
れを支持部２４で支持している枠体２３から構成されて
いる。２５は酸化亜鉛薄膜で振動子２２の表面に形成さ
れている。２６は酸化亜鉛薄膜２５の上に形成されたＴ
ａ層、２７はＴａ層２６の上に形成されたへρ電極であ
る。In the figure, reference numeral 21 indicates a vibrator body, which is composed of a vibrator 22 and a frame 23 that supports the vibrator 22 with a support portion 24. 25 is a zinc oxide thin film formed on the surface of the vibrator 22. 26 is a T formed on the zinc oxide thin film 25.
The a-layer 27 is a ρ electrode formed on the Ta layer 26.
第４図は同じくこの発明を他の屈曲振動モードの振動子
に適用した例の側面図である。FIG. 4 is a side view of an example in which the present invention is applied to another bending vibration mode vibrator.
図において、３１はセラミクス、プラスチック、ゴムな
どの基板、この基板３１表面には、Ａρ電極第５図は同
じくこの発明を拡がり振動モードの振動子に適用した例
を示す側面図である。In the figure, reference numeral 31 is a substrate made of ceramics, plastic, rubber, etc., and on the surface of this substrate 31 is an Aρ electrode. FIG.
図において、４１は酸化亜鉛薄膜、４２は酸化亜鉛薄膜
４１の両面に形成されたＴａ層、４３は１８層４２の上
に形成されたへρ電極である。In the figure, 41 is a zinc oxide thin film, 42 is a Ta layer formed on both sides of the zinc oxide thin film 41, and 43 is a ρ electrode formed on the 18 layer 42.
第６図は同じくこの発明を厚み振動モードの振動子に適
用した例を示す側面図である。FIG. 6 is a side view showing an example in which the present invention is applied to a thickness vibration mode vibrator.
図において、５１は３ｉ、５ｉ０２などからなる基板、
基板５１の上には／ｌ電極５２．１８層５３が順次形成
されている。さらに１８層５３の上には酸化亜鉛薄膜５
４が形成されている。この酸化亜鉛薄膜５４が形成され
ている位置に相当する基板５１には空部５１ａが形成さ
れている。酸化亜鉛薄膜５４の−ＬにはＴａ層５５、お
よびＡり電極５６が順次積層して形成されている。In the figure, 51 is a substrate made of 3i, 5i02, etc.
On the substrate 51, /l electrodes 52, 18 layers 53 are sequentially formed. Further, on the 18 layers 53 is a zinc oxide thin film 5.
4 is formed. A cavity 51a is formed in the substrate 51 corresponding to the position where the zinc oxide thin film 54 is formed. On the -L side of the zinc oxide thin film 54, a Ta layer 55 and an A electrode 56 are sequentially laminated.
次に具体的な実施例として、第２図に示した音叉振動子
についてこの発明にかかる酸化亜鉛薄膜の電極構造を適
用した例を説明する。Next, as a specific example, an example in which the electrode structure of the zinc oxide thin film according to the present invention is applied to the tuning fork vibrator shown in FIG. 2 will be described.
第２図を参照して説明すれば、振動子１１の上にスパッ
タリング法により酸化亜鉛薄ｒｆＡ１２を形成し、その
上にＴａ層１３を電子ビームにより １５０Ａの厚みに
形成し、さらにその上に厚みが１μからなるＡρ電極１
４を電子ビーム法により形成した。このようにして振動
周波数３２Ｋｌ−１ｚの振動子を作成した。To explain with reference to FIG. 2, a thin zinc oxide rfA layer 12 is formed on the vibrator 11 by sputtering, a Ta layer 13 is formed on it to a thickness of 150A by an electron beam, and then a Aρ electrode 1 consisting of 1μ
4 was formed by an electron beam method. In this way, a vibrator with a vibration frequency of 32 Kl-1z was created.
この振動子に直流電圧２０Ｖを印加し、１２０℃の温度
に １００００時間放置した。このときの振動周波数の
経時変化特性を試料数２０個につい−Ｃ測定したところ
第７図に示すような結果が得られた。図中実線はこの実
施例によるものである。また破線は従来例のへρ電極の
みからなるものについて、同様にして測定した結果を示
したものである。この振動周波数の経時変化特性（ΔＦ
／Ｆｏ）は次式より求めた。A DC voltage of 20 V was applied to this vibrator, and it was left at a temperature of 120° C. for 10,000 hours. When the -C measurement of the temporal change characteristics of the vibration frequency at this time was performed on 20 samples, the results shown in FIG. 7 were obtained. The solid line in the figure is based on this embodiment. Furthermore, the broken line shows the results of measurements made in the same manner for a conventional example consisting of only a ρ electrode. This vibration frequency change characteristic over time (ΔF
/Fo) was determined from the following formula.
また、直列共振抵抗（Ｒｏ ）および並列共振抵抗（Ｒ
ａ ）についてもそれぞれ同様に測定し、その結果を第
８図、第９図にそれぞれ示した。Also, the series resonant resistance (Ro) and the parallel resonant resistance (R
A) was also measured in the same manner, and the results are shown in FIGS. 8 and 9, respectively.
第１図〜第９図から明らかなように、この発明にかかる
ものは、従来例にくらべて、振動周波数の経時変化が小
さく、またＲｏの経時変化が小さく、さらにＲａの経時
変化も小さいなどの効果が得られている。As is clear from FIGS. 1 to 9, the device according to the present invention has a smaller change in vibration frequency over time, a smaller change in Ro over time, and a smaller change in Ra over time than the conventional example. effects have been obtained.
ここで、Ｒｏ 、Ｒａを測定したのは次のような理由に
よる。Here, the reason why Ro and Ra were measured is as follows.
まず、酸化亜鉛薄膜についてその等両回路を示せば第１
０図のようになる。図中、Ｃｄは並列容量を示し、酸化
亜鉛薄膜をコンデンサとして考えた場合の静電容量に近
い値である。Ｒｏは直列共振抵抗、Ｃｏは等価容量、Ｌ
ｏは等価インダクタンスである。First, if we show both circuits for a zinc oxide thin film, the first
It will look like Figure 0. In the figure, Cd indicates parallel capacitance, which is a value close to the capacitance when the zinc oxide thin film is considered as a capacitor. Ro is series resonant resistance, Co is equivalent capacitance, L
o is the equivalent inductance.
またＲ ａは近似的に次式より求められるものである。Moreover, R a is approximately determined by the following equation.
の関係から、直列共振周波数（ｆｏ）に対応し、このＲ
ｏが大ぎくなれば発振に大きな増幅度が必要となり、発
振条件の低下をもたらすことになることが伺える。From the relationship, this R corresponds to the series resonant frequency (fo).
It can be seen that if o becomes too large, a large degree of amplification is required for oscillation, resulting in a deterioration of the oscillation conditions.
またＲａは同じく第１１図に示したインピーダンスと周
波数の関係から、***振周波数（ｆａ）に対応し、この
Ｒａが小さくなれば発振に十分な位相変化がとれず、こ
れもまた発振条件の低下をもたらすことになる。Also, from the relationship between impedance and frequency shown in Figure 11, Ra corresponds to the anti-resonance frequency (fa), and if Ra becomes small, a sufficient phase change for oscillation cannot be achieved, which also reduces the oscillation conditions. It will bring about.
第８図、第９図から明らかなように、この発明の実施例
によれば、従来例のへρ電極のものにくらべ、Ｒｏ 、
Ｒａの経時変化が小さく、このことからこの発明にかか
る酸化亜鉛薄膜の電極構造は安定な電気的特性を有する
とともに、高温負荷寿命試験に対しても安定した特性を
示すものであると理解することができ、安定した発振を
期待することができるか否かの目安とする。As is clear from FIGS. 8 and 9, according to the embodiment of the present invention, Ro,
It can be understood that the change in Ra over time is small, and from this it can be understood that the electrode structure of the zinc oxide thin film according to the present invention has stable electrical characteristics and also exhibits stable characteristics even in high temperature load life tests. This is used as a guideline to determine whether stable oscillation can be expected.
以上この発明によれば、酸化並鉛薄膜とへρ電極との間
にＡβの拡散防止層としてＴａ層を介在させたものであ
り、従来のものにくらべて実用上十分な特性を示ず酸化
亜鉛ｔｓｉを提供することができる。特にこの発明によ
れば、高温負荷寿命試験に対してＲｏ 、Ｒａの変化が
小さく、周波数変化が少ないなど信頼性の高い酸化亜鉛
薄膜が得られる。As described above, according to the present invention, a Ta layer is interposed between the normal lead oxide thin film and the ρ electrode as a diffusion prevention layer for Aβ, and compared to the conventional one, it does not exhibit sufficient characteristics for practical use. Zinc tsi can be provided. Particularly, according to the present invention, a highly reliable zinc oxide thin film with small changes in Ro and Ra and little change in frequency can be obtained in a high-temperature load life test.
第１図は音叉振動子の一例を示（側面図、第２図は音叉
振動子にこの発明にかかる酸化亜鉛薄膜の電極構造を適
用した例を示す側面図、第３図は音片振動子にこの発明
にかかる酸化亜鉛薄膜の電極構造を適用した例の斜視図
、第４図〜第６図は同じくこの発明にかかる酸化亜鉛薄
膜の電極構造を各振動子に適用した例の側面図、第７図
はこの発明の具体的実施例にもとづく振動周波数の経時
変化特性図、第８図は同じ＜Ｒｏの経時変化特性図、第
９図は同じ＜Ｒａの経時変化特性図、第１０図は酸化亜
鉛薄膜の等両回略図、第１１図はインピーダンスと周波
数の関係特性図ぐある。
１１・・・・・・基板、１２・・・・・・酸化亜鉛薄膜
、１３・・・・・・ｌ”ａ層、１４・・・・・・Ａρ電
極。
特 許 出 願 人
株式会社村田製作所
１０
第４ 図
帖５図
弔乙肥
Ｔ／ｆｆ５（／ｆσｑリ
ア’ｌＮ５（ｆ−１を層りFig. 1 shows an example of a tuning fork vibrator (side view), Fig. 2 is a side view showing an example in which the zinc oxide thin film electrode structure according to the present invention is applied to a tuning fork vibrator, and Fig. 3 shows a tuning fork vibrator. FIGS. 4 to 6 are side views of examples in which the zinc oxide thin film electrode structure according to the present invention is applied to each vibrator; FIG. 7 is a characteristic diagram of vibration frequency change over time based on a specific embodiment of the present invention, FIG. 8 is a characteristic diagram of change over time of the same <Ro, FIG. 9 is a characteristic diagram of change over time of the same <Ra, and FIG. 11 is a diagram of the relationship between impedance and frequency. 11...Substrate, 12...Zinc oxide thin film, 13...・l"a layer, 14...Aρ electrode. Patent applicant: Murata Manufacturing Co., Ltd. the law of nature
Claims (1)
たことを特徴とする酸化亜鉛薄膜の電極構造。An electrode structure of a zinc oxide thin film, characterized in that a Ta layer is interposed between the surface of the zinc oxide thin film and a β electrode.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11444782A JPS595722A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
| US06/509,028 US4445066A (en) | 1982-06-30 | 1983-06-29 | Electrode structure for a zinc oxide thin film transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11444782A JPS595722A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS595722A true JPS595722A (en) | 1984-01-12 |
| JPH0115207B2 JPH0115207B2 (en) | 1989-03-16 |
Family
ID=14637956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11444782A Granted JPS595722A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS595722A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0860943A2 (en) * | 1997-02-20 | 1998-08-26 | Murata Manufacturing Co., Ltd. | Surface acoustic wave device |
| US7280180B2 (en) | 2002-03-19 | 2007-10-09 | Lg.Philips Lcd Co., Ltd. | Liquid crystal display panel with first and second dummy UV sealants and method for fabricating the same |
-
1982
- 1982-06-30 JP JP11444782A patent/JPS595722A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0860943A2 (en) * | 1997-02-20 | 1998-08-26 | Murata Manufacturing Co., Ltd. | Surface acoustic wave device |
| EP0860943B1 (en) * | 1997-02-20 | 2003-05-07 | Murata Manufacturing Co., Ltd. | Surface acoustic wave device |
| US7280180B2 (en) | 2002-03-19 | 2007-10-09 | Lg.Philips Lcd Co., Ltd. | Liquid crystal display panel with first and second dummy UV sealants and method for fabricating the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0115207B2 (en) | 1989-03-16 |
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