JPS595726A - Electrode structure of thin film of zinc oxide - Google Patents
Electrode structure of thin film of zinc oxideInfo
- Publication number
- JPS595726A JPS595726A JP11445182A JP11445182A JPS595726A JP S595726 A JPS595726 A JP S595726A JP 11445182 A JP11445182 A JP 11445182A JP 11445182 A JP11445182 A JP 11445182A JP S595726 A JPS595726 A JP S595726A
- 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 90
- 239000011787 zinc oxide Substances 0.000 title claims abstract description 45
- 239000010409 thin film Substances 0.000 title claims description 27
- 238000000034 method Methods 0.000 abstract description 8
- 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
- 239000000758 substrate Substances 0.000 description 6
- 239000010408 film Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 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
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 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
- 238000005259 measurement Methods 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
- 230000002265 prevention Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000007740 vapor deposition Methods 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。FIG. 1 is a side view showing an example of a tuning fork vibrator.
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、３ａには酸化
亜鉛簿膜４．５が形成されている。In the figure, reference numeral 1 indicates the main body of the tuning fork vibrator, and reference numeral 2.3 indicates the leg portions of the main body 1. Zinc oxide films 4.5 are formed on the side walls 2a and 3a of the leg portions 2.3.
この酸化亜鉛ＷＩＩＩ１４．５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１膜４．５の上に形成されたへβ
電極を示す。This zinc oxide WIII14.5 is formed by a vacuum evaporation method, a sputtering method, an ion blasting method, or the like. 6.7 is β formed on zinc oxide 1 film 4.5
Shows electrodes.
このへ！電極６．７は安価で承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３０
００〜１００ＯＯＡの膜厚の範囲で形成される。To this! Electrode 6.7 was chosen because it was inexpensive and could be bonded, and was made by electron beam evaporation.
It is formed with a film thickness in the range of 00 to 100 OOA.
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！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ＡＮ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／ｌが
拡散することによって酸化亜鉛ｉ１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. In other words, to! Since the electrode itself exhibits high affinity, there is a drawback that AN diffuses into the zinc oxide thin film, deteriorating the electrical characteristics. That is, a phenomenon was observed in which the electrical properties of the zinc oxide i1 film, such as the vibration frequency, were significantly changed due to the diffusion of trivalent /l 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
的とする。The present invention was made against this background, and an object of the present invention 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
叉撮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 sensor.
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Ｔｉ層、１４はへβ電極である。このうち
１１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 Ti layer, and 14 is a beta electrode. Of these, 11 layers 13 are 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ｌＩ！２５の上に形成され
たＴｉ層、２７はＴ ｉ層２６の上に形成されたへ！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 zinc oxide thin lI! A Ti layer is formed on the Ti layer 25, and a Ti layer 27 is formed on the Ti layer 26! It is an electrode.
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、へβ電極３２、Ｔｉ
層３３、酸化亜鉛薄膜３４、Ｔｉ層３５、およびＡρ電
極３６が順次形成されている。In the figure, 31 is a substrate made of ceramics, plastic, rubber, etc. On the surface of this substrate 31, a β electrode 32, a Ti
A layer 33, a zinc oxide thin film 34, a Ti layer 35, and an Aρ electrode 36 are formed in this order.
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８図において、４１は酸
化亜鉛薄膜、４２は酸化亜鉛ｗ１ ｍ ４１（７） 両
面ニ形成すｔＬ タＴ ｉ ＩＩ、４３ハＴ ｉ ＩＩ
４２の上に形成されたへ！電極である。FIG. 5 is a side view showing an example in which the present invention is applied to a spread vibration mode vibrator. In FIG. T i II, 43ha T i II
Formed on 42! It is an electrode.
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Ｓｉ、ＳｉＯ２などからなる基板、
基板５１の上にはＡＪ２電極５２．１１層５３が順次形
成されている。さらに１１層５３の上には酸化亜鉛薄ｗ
Ａ５４が形成されている。この酸化亜鉛ｉＪ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の上には１１層５５
、およびＡρ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 Si, SiO2, etc.
On the substrate 51, AJ2 electrodes 52, 11 layers 53 are sequentially formed. Furthermore, there is a thin layer of zinc oxide on top of the 11th layer 53.
A54 is formed. A cavity 51a is formed in the substrate 51 corresponding to the position where the zinc oxide iJ film 54 is formed. Eleven layers 55 are formed on the zinc oxide thin film 54.
, and Aρ electrode 56 are sequentially stacked.
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膜１２を形成し、その上に
Ｔｉを層１３を電子ビーム法により３００Ａの厚みに形
成し、さらにその上に厚みが１μからなるへρ電極１４
を電子ビーム法により形成した。To explain with reference to FIG. 2, a zinc oxide thin film 12 is formed on the vibrator 11 by sputtering, a Ti layer 13 is formed on it to a thickness of 300A by an electron beam method, and then The ρ electrode 14 has a thickness of 1μ.
was formed by an electron beam method.
このようにして振動周波数３２Ｋｌ−１ｚの振動子を作
成した。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個について測定したところ第１
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ＡＵ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／Ｆ
ｏ ）は次式また、直列共振抵抗（Ｒｏ ）についても
同様に測定し、その結果を第８図にそれぞれ示した。A DC voltage of 20 V was applied to this vibrator, and the vibrator was left at a temperature of 120° C. for 10,000 hours. At this time, the temporal change characteristics of the vibration frequency were measured for 20 samples.
The results shown in the figure 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 only of AU electrodes. This vibration frequency change characteristic over time (ΔF/F
The series resonant resistance (Ro) was also measured in the same manner, and the results are shown in FIG. 8.
第７図〜第８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かつその値も小さい
などの効果が得られている。As is clear from FIGS. 7 and 8, the device according to the present invention has effects such as a smaller change in vibration frequency over time and a smaller change in Ro over time than the conventional example. It has been obtained.
ここで、Ｒｏを測定したのは次のような理由による。The reason why Ro was measured here 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９
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、Ｌｏ
は等価インダクタンスである。First, if we show both circuits for zinc oxide thin film,
It will look like the figure. 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, Lo
is the equivalent inductance.
Ｒｏは第１０図に示したインピーダンスと周波数の関係
から、直列共振周波数（ｆｏ）に対応し、このＲｏが大
き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 between impedance and frequency shown in Figure 10, Ro corresponds to the series resonant frequency (fo), and if this Ro becomes large, a large degree of amplification will be required for oscillation, resulting in a decrease in the oscillation conditions. I can see it.
第８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β電極のものにくらべＲＯ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づるとともに、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
るか否かの目安となる。As is clear from FIG. 8: According to the embodiment of the present invention, the change in RO over time is smaller than that of the conventional β-electrode, and from this, the electrode structure of the zinc oxide thin film according to the present invention is stable. It can be understood that this material has excellent electrical characteristics and also shows stable characteristics even in high temperature load life tests, which can be used as an indicator of whether stable oscillation can be expected.
以上この発明によれば、酸化亜鉛薄膜とへρ電極との間
にＡρの拡散防止層としてＴｉ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す酸化
亜鉛薄膜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 Ti layer is interposed between the zinc oxide thin film and the hep electrode as a diffusion prevention layer of Aρ, and the zinc oxide thin film exhibits practically sufficient characteristics compared to conventional ones. can be provided. In particular, according to the present invention, a highly reliable zinc oxide thin film with small changes in Ro and small changes 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す側面図、第２図は音叉
振動子にこの発明にががる酸化亜鉛１１１１１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図は酸化亜鉛薄膜の等何回略図、第１０図はイ
ンピーダンスと周波数の関係特性図である。
１１・・・・・・基板、１２・・・・・・酸化亜鉛薄膜
、１３・・・・・・Ｔｉ層、１４・・・・・・Ａρ両電
極
特 許 出 願 人
株式会社村田製作所
第 ５図
”ｒｌＮＥ （ＨＯｔ／Ｆ）
第３ 図
Ｔ１Ｍ＆ （／１θｖＢ、）Figure 1 is a side view showing an example of a tuning fork vibrator, Figure 2 is a side view showing an example in which the electrode structure of zinc oxide 11111 according to the present invention is applied to a tuning fork vibrator, and Figure 3 is 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 schematic diagram of a zinc oxide thin film, and FIG. is a characteristic diagram showing the relationship between impedance and frequency. 11...Substrate, 12...Zinc oxide thin film, 13...Ti layer, 14...Aρ double electrode patent applicant Murata Manufacturing Co., Ltd. Figure 5 "rlNE (HOt/F) Figure 3 T1M& (/1θvB,)
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 11@ is interposed between the surface of the zinc oxide thin film and the AQ electrode.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11445182A JPS595726A (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 |
|---|---|---|---|
| JP11445182A JPS595726A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS595726A true JPS595726A (en) | 1984-01-12 |
| JPH0115211B2 JPH0115211B2 (en) | 1989-03-16 |
Family
ID=14638054
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11445182A Granted JPS595726A (en) | 1982-06-30 | 1982-06-30 | Electrode structure of thin film of zinc oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS595726A (en) |
-
1982
- 1982-06-30 JP JP11445182A patent/JPS595726A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0115211B2 (en) | 1989-03-16 |
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