JPH0574022U - Electrode structure of piezoelectric vibrator - Google Patents
Electrode structure of piezoelectric vibratorInfo
- Publication number
- JPH0574022U JPH0574022U JP2096392U JP2096392U JPH0574022U JP H0574022 U JPH0574022 U JP H0574022U JP 2096392 U JP2096392 U JP 2096392U JP 2096392 U JP2096392 U JP 2096392U JP H0574022 U JPH0574022 U JP H0574022U
- Authority
- JP
- Japan
- Prior art keywords
- electrode film
- piezoelectric vibrator
- gold
- electrode
- film made
- 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.)
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- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
(57)【要約】
【構成】 活性な金属からなる第１の電極膜と、金より
も電気抵抗値の低い金属からなる第２の電極膜と、金か
らなる第３の電極膜とを圧電振動板上に設ける。
【効果】 化学的に安定な金からなる第３の電極膜を第
２の電極膜上に設けることにより、第２の電極膜が周囲
の雰囲気から保護され、振動子の特性の劣化がなくな
り、安定した特性を備える圧電振動子を提供することが
可能となる。
(57) [Summary] [Structure] A first electrode film made of an active metal, a second electrode film made of a metal having an electric resistance value lower than that of gold, and a third electrode film made of gold are piezoelectrically formed. Provide on the diaphragm. [Effect] By providing the third electrode film made of chemically stable gold on the second electrode film, the second electrode film is protected from the surrounding atmosphere, and the deterioration of the characteristics of the vibrator is eliminated. It is possible to provide a piezoelectric vibrator having stable characteristics.
Description
【０００１】[0001]
本考案は圧電振動子の電極構造に関するものである。 The present invention relates to an electrode structure of a piezoelectric vibrator.
【０００２】[0002]
従来より圧電振動子の電極構造としては圧電振動板上にニッケル（Ｎｉ）ある いはクロム（Ｃｒ）からなる第１の電極膜と、金（Ａｕ）あるいは銀（Ａｇ）か らなる第２の電極膜との二重層からなる電極膜が広く利用されている。 Conventionally, as an electrode structure of a piezoelectric vibrator, a first electrode film made of nickel (Ni) or chromium (Cr) on a piezoelectric vibration plate and a second electrode film made of gold (Au) or silver (Ag) are provided. An electrode film composed of a double layer with an electrode film is widely used.
【０００３】 ここで第１の電極膜は圧電振動板と第２電極膜との密着を高める密着層の役割 を持ち、第２の電極膜は圧電振動板を振動させるための励振層の役割を持つ。Here, the first electrode film serves as an adhesion layer that enhances the adhesion between the piezoelectric diaphragm and the second electrode film, and the second electrode film serves as an excitation layer for vibrating the piezoelectric diaphragm. To have.
【０００４】 圧電振動子の基本特性の１つに、この圧電振動子のクリスタルインピーダンス がある。このクリスタルインピーダンスの値は低い方がよい。One of the basic characteristics of the piezoelectric vibrator is the crystal impedance of the piezoelectric vibrator. The lower the crystal impedance value, the better.
【０００５】 このクリスタルインピーダンスは、電極膜、とくに第２の電極膜の電気的な抵 抗値に起因する。This crystal impedance is caused by the electrical resistance value of the electrode film, especially the second electrode film.
【０００６】 上述のように、従来から第２の電極膜には金あるいは銀が用いられているが、 両者の電気抵抗値を比べると、金よりも銀の方が電気抵抗値が低い。このため、 近年は第２の電極膜として、銀が用いられることが多い。As described above, conventionally, gold or silver has been used for the second electrode film. However, comparing the electric resistance values of the two, silver has a lower electric resistance value than gold. Therefore, in recent years, silver is often used as the second electrode film.
【０００７】 さらに、第２の電極膜として金あるいは銀を用いる場合、金、銀いずれの材料 であっても、第２の電極膜の厚さは数百ｎｍ必要であり、金よりも銀の方が価格 的にも安く、圧電振動子のコストの面でも利点がある。Further, when gold or silver is used as the second electrode film, the thickness of the second electrode film needs to be several hundreds nm regardless of whether the material is gold or silver. The price is cheaper, and there is an advantage in the cost of the piezoelectric vibrator.
【０００８】[0008]
しかしながら、銀は貴金属ではあるものの、周囲の雰囲気中のガス分子、とく に硫黄成分と反応しやすく、化合物を形成してしまう。 However, although silver is a noble metal, it easily reacts with gas molecules in the surrounding atmosphere, especially sulfur components, and forms a compound.
【０００９】 圧電振動子に化合物が形成されると、電気抵抗値が高くなる。この結果、クリ スタルインピーダンスも高くなってしまうため、圧電振動子の基本特性が劣化す る。しかもそのうえ、化合物を形成することにより第２の電極膜の質量増加も伴 う。When a compound is formed on the piezoelectric vibrator, the electric resistance value increases. As a result, the crystal impedance also rises, and the basic characteristics of the piezoelectric vibrator deteriorate. Moreover, by forming the compound, the mass of the second electrode film also increases.
【００１０】 圧電振動子の性能を示すものとして、クリスタルインピーダンスなどの基本特 性の他に経時変化がある。ここで経時変化とは、ある一定期間前後の圧電振動子 の発振周波数のずれを示すものである。The performance of the piezoelectric vibrator is changed with time in addition to the basic characteristics such as crystal impedance. Here, the change with time refers to a deviation of the oscillation frequency of the piezoelectric vibrator before and after a certain fixed period.
【００１１】 この経時変化である周波数変化の原因の一つに、圧電振動板への付加質量の変 化がある。もちろん、この経時変化が小さい圧電振動子の方が性能は良いことに なる。One of the causes of the frequency change, which is the change over time, is the change in the mass added to the piezoelectric diaphragm. Of course, the performance is better with the piezoelectric vibrator whose change over time is smaller.
【００１２】 すなわち、第２の電極膜に銀を用いている場合には、上述のように周囲の雰囲 気中のガス分子と反応し化合物を形成するために、質量の増加が起こるので、経 時変化に対しては不都合が生じる。That is, when silver is used for the second electrode film, the mass increases because it reacts with gas molecules in the surrounding atmosphere to form a compound as described above. Inconvenience occurs with respect to changes over time.
【００１３】 圧電振動子は、電極膜を形成した圧電振動板を容器内に封止して作製する。こ のため銀が周囲の雰囲気中のガス分子と反応しやすく、圧電振動子の基本特性の 劣化ならびに経時変化の悪化を引き起こすため、銀を第２電極膜に用いる場合に は、反応しやすいガス分子が容器内に取り込まれないように、封止するときの容 器内の雰囲気の形成に露点計などを用いて細心の注意を払う必要がある。The piezoelectric vibrator is manufactured by sealing a piezoelectric vibrating plate having an electrode film formed inside a container. For this reason, silver easily reacts with gas molecules in the surrounding atmosphere, which causes deterioration of the basic characteristics of the piezoelectric vibrator and deterioration of deterioration with time. Therefore, when silver is used for the second electrode film, a gas that easily reacts In order to prevent the molecules from being taken into the container, it is necessary to pay close attention to the atmosphere inside the container when sealing by using a dew point meter or the like.
【００１４】 したがって圧電振動子の封止の工程における管理が面倒になる。現在、この封 止時の雰囲気管理は窒素雰囲気中で露点計を用いて行っているが、許容露点範囲 がかなり狭められてしまう。Therefore, management in the process of sealing the piezoelectric vibrator becomes troublesome. At present, the atmosphere at the time of sealing is controlled using a dew point meter in a nitrogen atmosphere, but the allowable dew point range will be narrowed considerably.
【００１５】 このため、電気抵抗値が低く、しかも周囲の雰囲気中のガス分子との反応がな い電極構造が望まれている。Therefore, there is a demand for an electrode structure that has a low electric resistance value and does not react with gas molecules in the surrounding atmosphere.
【００１６】 そこで、本考案の目的は、周囲の雰囲気中のガス成分との反応による圧電振動 子の基本特性の劣化、および経時変化の悪化が生じない電極構造を提供すること である。Therefore, an object of the present invention is to provide an electrode structure which does not cause deterioration of the basic characteristics of the piezoelectric vibrator due to reaction with a gas component in the surrounding atmosphere and deterioration of deterioration over time.
【００１７】[0017]
上記目的を達成するため、本考案の圧電振動子の電極構造は、活性な金属から なる第１の電極膜と、金よりも電気抵抗の低い金属からなる第２電極膜と、金か らなる第３の電極膜とを圧電振動板上に設ける。 In order to achieve the above object, the electrode structure of the piezoelectric vibrator of the present invention includes a first electrode film made of an active metal, a second electrode film made of a metal having an electric resistance lower than that of gold, and gold. A third electrode film is provided on the piezoelectric vibrating plate.
【００１８】[0018]
以下図面により本考案の一実施例を説明する。図１は本考案における圧電振動 子の電極構造を示す断面図である。 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an electrode structure of a piezoelectric vibrator according to the present invention.
【００１９】 図１に示すように、圧電振動板１０上に第１の電極膜１１を設け、この第１の 電極膜１１上に第２の電極膜１２を設ける。第１の電極膜１１は、第２の電極膜 １２と圧電振動板１０との密着力を高める密着層の役割をもつ。さらに第２の電 極膜１２上に、保護層としての役割をもつ第３の電極膜１３を設ける。As shown in FIG. 1, the first electrode film 11 is provided on the piezoelectric vibrating plate 10, and the second electrode film 12 is provided on the first electrode film 11. The first electrode film 11 serves as an adhesion layer that enhances the adhesion between the second electrode film 12 and the piezoelectric vibrating plate 10. Further, a third electrode film 13 having a role as a protective layer is provided on the second electrode film 12.
【００２０】 本考案の電極構造を得るためには、まず圧電振動板１０上に、圧電振動板１０ と第２の電極膜１２との密着力を高める密着層の役割を持つ第１の電極膜１１と してのニッケルを、膜厚十数ｎｍ以上形成する。次に圧電振動子を励振させるた めの第２の電極膜１２としての銀を、膜厚数百ｎｍ形成し、さらに第３の電極膜 １３としての金を形成する。In order to obtain the electrode structure of the present invention, first, on the piezoelectric vibrating plate 10, a first electrode film having a role of an adhesion layer that enhances an adhesion force between the piezoelectric vibrating plate 10 and the second electrode film 12. Nickel 11 is formed with a film thickness of 10 nm or more. Next, silver as the second electrode film 12 for exciting the piezoelectric vibrator is formed to a film thickness of several hundreds nm, and further gold as the third electrode film 13 is formed.
【００２１】 この第３の電極膜１３は、第２の電極膜１２の劣化を抑えられれば良いため、 形成した膜にピンホールが形成されず連続的になる厚さ５０ｎｍより厚く形成す れば良い。The third electrode film 13 only needs to be capable of suppressing the deterioration of the second electrode film 12. Therefore, if the third electrode film 13 is formed thicker than 50 nm, which is continuous without pinholes being formed in the formed film. good.
【００２２】 それぞれの第１の電極膜１１と第２の電極膜１２と第３の電極膜１３との形成 には、真空蒸着装置あるいはスパッタリング装置を用いる。A vacuum vapor deposition apparatus or a sputtering apparatus is used for forming each of the first electrode film 11, the second electrode film 12, and the third electrode film 13.
【００２３】 真空蒸着装置では蒸発源、スパッタリング装置ではターゲットを３種類用意す れば、第１の電極膜１１と第２の電極膜１２と第３の電極膜１３との形成までを 連続して行うことができるため、第２の電極膜１２が外気に触れることはない。 したがって第２の電極膜１２が変質することはない。If three types of targets are prepared for the evaporation source in the vacuum deposition apparatus and the sputtering apparatus, the formation of the first electrode film 11, the second electrode film 12, and the third electrode film 13 can be continuously performed. Since it can be performed, the second electrode film 12 is not exposed to the outside air. Therefore, the quality of the second electrode film 12 does not change.
【００２４】 本考案においては、第３の電極膜１３として用いる金は、化学的に安定なため に、周囲の雰囲気中のガス成分などと反応することがない。In the present invention, the gold used as the third electrode film 13 is chemically stable and therefore does not react with gas components in the surrounding atmosphere.
【００２５】 このため、金を周囲の雰囲気と接する最上層の第３の電極膜１３として用いる ことにより、第２の電極膜１２に用いる銀が周囲の雰囲気と接することがなくな る。Therefore, by using gold as the uppermost third electrode film 13 in contact with the surrounding atmosphere, silver used in the second electrode film 12 is prevented from coming into contact with the surrounding atmosphere.
【００２６】 この結果、従来の電極構造では問題になる電極膜が、周囲の雰囲気中のガス成 分との反応によって圧電振動子の基本特性の劣化がなく、さらに経時変化の悪化 が発生しなくなる。As a result, the electrode film, which is a problem in the conventional electrode structure, does not deteriorate the basic characteristics of the piezoelectric vibrator due to the reaction with the gas components in the surrounding atmosphere, and the deterioration over time does not occur. ..
【００２７】 すなわち、周囲の雰囲気中のガス分子と反応しやすい銀を第２の電極膜１２と して用いても、さらにその上に化学的に安定な金を第３の電極膜１３として薄く 設けることにより、第２の電極膜１２として用いた銀の低い電気抵抗値を有効に 利用したまま、周囲の雰囲気中のガス分子と反応がない。したがって、圧電振動 子の基本特性の劣化、ならびに経時変化の悪化が発生しない電極構造を得ること ができる。しかも、このとき第３の電極膜としての金の厚さは、最低５０ｎｍ程 度有れば良く、非常に薄くて済むのでコストの面でも銀の利点を損なわない。That is, even if silver that easily reacts with gas molecules in the surrounding atmosphere is used as the second electrode film 12, chemically stable gold is thinly formed on the second electrode film 12 as the third electrode film 13. By providing it, there is no reaction with gas molecules in the surrounding atmosphere while effectively utilizing the low electric resistance value of silver used as the second electrode film 12. Therefore, it is possible to obtain an electrode structure in which the basic characteristics of the piezoelectric vibrator are not deteriorated and the deterioration with time is not deteriorated. Moreover, at this time, the thickness of the gold as the third electrode film may be at least about 50 nm, which is very thin, and the advantage of silver is not impaired in terms of cost.
【００２８】 さらに、上述したように第３の電極膜１３によって、第２の電極膜１２が周囲 の雰囲気から保護されているので、圧電振動子の完成体を得るため、この電極膜 が形成された圧電振動板１０を容器内に封止するときの容器内の雰囲気管理にお ける許容露点範囲も、従来の圧電振動子の電極構造の場合よりも広くなり工程の 管理も容易になる。Furthermore, since the second electrode film 12 is protected from the surrounding atmosphere by the third electrode film 13 as described above, this electrode film is formed in order to obtain a completed piezoelectric vibrator. Also, the permissible dew point range in the atmosphere management in the container when the piezoelectric vibrating plate 10 is sealed in the container is wider than in the case of the conventional electrode structure of the piezoelectric vibrator, and the process management is easy.
【００２９】 なお、以上の説明においては第１の電極膜１１にニッケルを用いた場合を示し たが、第１の電極膜１１はクロムやチタン（Ｔｉ）などの活性な金属でも同様な 効果が得られる。Although the case where nickel is used for the first electrode film 11 has been shown in the above description, the same effect can be obtained even if the first electrode film 11 is an active metal such as chromium or titanium (Ti). can get.
【００３０】 またさらに、第２の電極膜１２としては銀を用い場合を示したが、第２の電極 膜１２は銅など電気抵抗値の低い金属を用いても同様な効果が得られる。Furthermore, although the case where silver is used as the second electrode film 12 is shown, the same effect can be obtained by using a metal having a low electric resistance value such as copper for the second electrode film 12.
【００３１】[0031]
上記の説明のように本考案によれば、圧電振動板に活性な金属からなる第１の 電極膜と、電気抵抗値の低い金属からなる第２の電極膜とを積層した上に、さら に金からなる第３の電極膜を薄く設けている。このため第２の電極膜が第３の電 極膜によって保護され、第２電極膜が周囲の雰囲気に接することがなくなる。従 って、たとえ周囲の雰囲気と反応しやすい材料であっても、金よりも電気抵抗が 低い材料を容易に第２の電極膜として用いることが可能となる。これによって、 圧電振動子の基本特性の劣化、ならびに経時変化の悪化のない圧電振動子を提供 することが可能となる。 As described above, according to the present invention, the piezoelectric vibrating plate is laminated with the first electrode film made of an active metal and the second electrode film made of a metal having a low electric resistance value, and further. A thin third electrode film made of gold is provided. Therefore, the second electrode film is protected by the third electrode film, and the second electrode film does not come into contact with the surrounding atmosphere. Therefore, even a material that easily reacts with the surrounding atmosphere can be easily used as the second electrode film as a material having an electric resistance lower than that of gold. As a result, it is possible to provide a piezoelectric vibrator that does not deteriorate the basic characteristics of the piezoelectric vibrator and its deterioration over time.
【図１】本考案における圧電振動子の電極構造を示す断
面図である。FIG. 1 is a sectional view showing an electrode structure of a piezoelectric vibrator according to the present invention.
１０ 圧電振動板 １１ 第１の電極膜 １２ 第２の電極膜 １３ 第３の電極膜 10 Piezoelectric vibrating plate 11 First electrode film 12 Second electrode film 13 Third electrode film
Claims (1)
属からなる第１の電極膜と、金よりも電気抵抗値の低い
金属からなる第２の電極膜と、金からなる第３の電極膜
とからなることを特徴とする圧電振動子の電極構造。1. An electrode film provided on a piezoelectric vibrator comprises a first electrode film made of an active metal, a second electrode film made of a metal having an electric resistance value lower than that of gold, and a third electrode film made of gold. An electrode structure for a piezoelectric vibrator, comprising an electrode film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2096392U JPH0574022U (en) | 1992-03-09 | 1992-03-09 | Electrode structure of piezoelectric vibrator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2096392U JPH0574022U (en) | 1992-03-09 | 1992-03-09 | Electrode structure of piezoelectric vibrator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0574022U true JPH0574022U (en) | 1993-10-08 |
Family
ID=12041833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2096392U Pending JPH0574022U (en) | 1992-03-09 | 1992-03-09 | Electrode structure of piezoelectric vibrator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0574022U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008042873A (en) * | 2006-08-01 | 2008-02-21 | Txc Corp | Electrode structure and piezoelectric crystal oscillator |
-
1992
- 1992-03-09 JP JP2096392U patent/JPH0574022U/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008042873A (en) * | 2006-08-01 | 2008-02-21 | Txc Corp | Electrode structure and piezoelectric crystal oscillator |
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