JPS60147180A - Piezoelectric element - Google Patents
Piezoelectric elementInfo
- Publication number
- JPS60147180A JPS60147180A JP59001907A JP190784A JPS60147180A JP S60147180 A JPS60147180 A JP S60147180A JP 59001907 A JP59001907 A JP 59001907A JP 190784 A JP190784 A JP 190784A JP S60147180 A JPS60147180 A JP S60147180A
- Authority
- JP
- Japan
- Prior art keywords
- zinc oxide
- film
- film thickness
- electrode
- oxide thin
- 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.)
- Pending
Links
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000011787 zinc oxide Substances 0.000 claims abstract description 22
- 239000010409 thin film Substances 0.000 claims abstract description 20
- 238000004544 sputter deposition Methods 0.000 claims abstract description 11
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 239000010408 film Substances 0.000 abstract description 21
- 239000010931 gold Substances 0.000 abstract description 20
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 abstract description 13
- 229910052737 gold Inorganic materials 0.000 abstract description 13
- 239000011651 chromium Substances 0.000 abstract description 5
- 230000008878 coupling Effects 0.000 abstract description 4
- 238000010168 coupling process Methods 0.000 abstract description 4
- 238000005859 coupling reaction Methods 0.000 abstract description 4
- 239000007789 gas Substances 0.000 abstract description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 3
- 238000006243 chemical reaction Methods 0.000 abstract description 3
- 229910052804 chromium Inorganic materials 0.000 abstract description 3
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 abstract description 2
- 238000001755 magnetron sputter deposition Methods 0.000 abstract description 2
- 230000035945 sensitivity Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 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
- 150000002739 metals Chemical class 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000005546 reactive sputtering Methods 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
- RNWHGQJWIACOKP-UHFFFAOYSA-N zinc;oxygen(2-) Chemical group [O-2].[Zn+2] RNWHGQJWIACOKP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は酸化亜鉛ＺｎＯを用いた薄膜圧電素子に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thin film piezoelectric element using zinc oxide ZnO.
酸化亜鉛は六方晶ウルツアイト構造をした結晶で、Ｃ軸
方向を圧電軸とする圧電体である。電気機械結合係数は
バルクの場合で０．３ と余り大きくないが、スパッタ
リングなどにより比較的容易に薄膜化できるため、弾性
表面波素子や超高周波トランスデユーサとして広く応用
されている。製造方法としては、気相成長（ＣＶＤ）法
とスパッタリング法があるが、スパッタリング法が主流
である。スパッタリングにも、直流スパッタリング、交
流スパッタリングがあり、またＺｎＯそのものをターゲ
ットとしてスパッタを行なう方法、Ｚｎをターゲットと
して酸素雰囲気中でスパッタを行なう反応性スパッタ法
など多様である。しかし、いずれの方法を用いた場合で
も薄膜化したことによる特性の劣下が避けられない。Zinc oxide is a crystal with a hexagonal wurtzite structure, and is a piezoelectric material whose piezoelectric axis is in the C-axis direction. Although the electromechanical coupling coefficient is not very large at 0.3 in the bulk case, it can be relatively easily made into a thin film by sputtering, etc., so it is widely applied as surface acoustic wave elements and ultra-high frequency transducers. Manufacturing methods include a vapor phase growth (CVD) method and a sputtering method, with the sputtering method being the mainstream. Sputtering includes direct current sputtering and alternating current sputtering, and there are various methods such as a method in which sputtering is performed using ZnO itself as a target, and a reactive sputtering method in which sputtering is performed in an oxygen atmosphere using Zn as a target. However, no matter which method is used, deterioration in characteristics due to thinning the film is unavoidable.
酸化亜鉛は非晶質基板上にほぼＣ軸配向した多結晶膜が
形成されるが、結晶性及び基板に対するＣ軸配向性の優
れた酸化亜鉛薄膜はど電気機械結合係数が高い、したが
って、結晶性及びＣ軸配向性の良い酸化亜鉛薄膜を形成
することが重要なポイントとなる。Zinc oxide forms a polycrystalline film with approximately C-axis orientation on an amorphous substrate, but a zinc oxide thin film with excellent crystallinity and C-axis orientation with respect to the substrate has a high electromechanical coupling coefficient, and therefore is crystalline. The important point is to form a zinc oxide thin film with good properties and C-axis orientation.
そこで１本発明の目的は結晶性、及びＣ軸配向性の良い
酸化亜鉛薄膜を用いて電気音響変換効率の高い圧電素子
を得ることにある。Therefore, one object of the present invention is to obtain a piezoelectric element with high electroacoustic conversion efficiency using a zinc oxide thin film with good crystallinity and C-axis orientation.
圧電素子を構成するためには、電圧を印加するための電
極が必要である。電極材としては、Ａ ｕ 。In order to configure a piezoelectric element, electrodes for applying voltage are required. As the electrode material, A u is used.
ＡＱ、Ｐｔなどがあるが、これらの金属を非晶質基板上
に形成すると（１１１）配向した多結晶膜となる。電極
材料としてＡｕを用いた場合、（１１１）配向したＡ
ｕ膜上に酸化亜鉛薄膜を形成すると、非晶質基板の場合
と同様にほぼＣ軸配向するが、酸化亜鉛薄膜の結晶性及
びＣ軸配向性は電極として用い゛たＡ’ｕの結晶性に大
きく依存していることが実験により明らかになった。Ａ
ｕは導電性が大きいため電極としては１００〜２００へ
の厚みがあればよい。しかし、Ａｕ電極の厚みを変えて
実験を行なったところ、膜厚が薄い場合には表面の結晶
性が悪く、その上に形成された酸化亜鉛薄膜の結晶性、
配向性も劣下することが明らかになった。There are AQ, Pt, etc., and when these metals are formed on an amorphous substrate, a polycrystalline film with (111) orientation is formed. When Au is used as an electrode material, (111) oriented A
When a zinc oxide thin film is formed on the U film, the C-axis orientation is almost the same as in the case of an amorphous substrate, but the crystallinity and C-axis orientation of the zinc oxide thin film depend on the crystallinity of the A'u film used as an electrode. Experiments have shown that it is highly dependent on A
Since u has high conductivity, the electrode only needs to have a thickness of 100 to 200 mm. However, when we conducted experiments with different thicknesses of the Au electrodes, we found that when the film thickness was thin, the surface crystallinity was poor, and the crystallinity of the zinc oxide thin film formed on it was poor.
It became clear that the orientation was also degraded.
そこで、本発明になる圧電素子は比較的膜厚の厚いＡｕ
電極上に形成された酸化亜鉛薄膜を有することを特徴と
している。この薄膜は結晶性及びＣ軸配向性に優れ、し
たがって電気機械結合係数が大きいため、高性能素子が
実現される。Therefore, the piezoelectric element according to the present invention is made of relatively thick Au film.
It is characterized by having a zinc oxide thin film formed on the electrode. This thin film has excellent crystallinity and C-axis orientation, and therefore has a large electromechanical coupling coefficient, so that a high-performance device can be realized.
以下、本発明を実施例を参照しながら詳しく説明する。Hereinafter, the present invention will be explained in detail with reference to Examples.
第１図に示すように、１０ｍｍφ×１０１１ＩＩ＋の石
英ガラスロッド１の両端面を光学研磨し、一方の端面に
極く薄いクロムＣｒと膜厚１００〜２００〇への金Ａｕ
を蒸着した。この電極２上に高周波マグネトロンスパッ
タリングにより膜厚的３μｍの酸化亜鉛薄膜３を形成し
た。スパッタ条件はすべて、基板温度を２２０℃、アル
ゴン−酸素（５０％−５０％）導入ガスのガス圧を３Ｐ
ａとした。膜厚の異なるＡｕ電極上に作成したＺｎ○膜
の結晶学的特性をＸ線回折で評価した。第２図に示すよ
うに金の膜厚が厚いほど、（００２）回折線のロッキン
グカーブより計算された標準偏差σは小さくなっている
。標準偏差σが大きい試料については、（００２）、（
００４）回折線強度が弱＜ （１０３） 。As shown in Fig. 1, both end surfaces of a 10 mmφ x 1011 II+ quartz glass rod 1 are optically polished, and one end surface is coated with extremely thin chromium Cr and gold Au to a thickness of 100 to 2000.
was deposited. A zinc oxide thin film 3 having a thickness of 3 μm was formed on this electrode 2 by high frequency magnetron sputtering. All sputtering conditions were a substrate temperature of 220°C and a gas pressure of argon-oxygen (50%-50%) introduced gas of 3P.
It was set as a. The crystallographic properties of Zn○ films prepared on Au electrodes with different film thicknesses were evaluated by X-ray diffraction. As shown in FIG. 2, the thicker the gold film, the smaller the standard deviation σ calculated from the rocking curve of the (002) diffraction line. For samples with large standard deviation σ, (002), (
004) Diffraction line intensity is weak (103).
（１０２）、（１０１）、（１００）回折線も現 ２わ
れ混合配向していることがわかった。次に、酸化亜鉛薄
膜上に２ｍｍφの穴のあいたモリブデンＭｏマスクを用
いて室温、で金を蒸着し、上部電極４とした。両電極間
に周波数０．１〜１．２ＧＨｚのバースト波を印加して
音波を発生させ、石英ロンドのもう一方の端面で反射し
て戻ってくる第１エコー強度を測定して、その周波数特
性を各試料について比較した。第２図に示すように、金
の膜厚が１００〇八付近を境にしてそれ以下の場合には
急激に感度が低下する。図中、相対感度の基準は、非常
に結晶性の良好な場合として基板にサファイア単結晶の
Ｃ板を用い、約２０００への金膜を形成した後、前記と
同様の方法で作成した試料の感度としている。金電極の
膜厚が１０００八以上であれば。The (102), (101), and (100) diffraction lines were also found to be mixedly oriented. Next, gold was vapor-deposited on the zinc oxide thin film at room temperature using a molybdenum Mo mask with holes of 2 mm diameter to form the upper electrode 4. A burst wave with a frequency of 0.1 to 1.2 GHz is applied between both electrodes to generate a sound wave, and the intensity of the first echo reflected back from the other end of the quartz iron is measured to determine its frequency characteristics. were compared for each sample. As shown in FIG. 2, when the gold film thickness reaches around 10,000 mm and is less than that, the sensitivity rapidly decreases. In the figure, the relative sensitivity is based on a sample prepared in the same manner as above, using a C plate of sapphire single crystal as the substrate and forming a gold film of about 2000 nm, in the case of very good crystallinity. Sensitivity. If the film thickness of the gold electrode is 10008 or more.
感度は基準から一５ｄＢ内にあり、圧電素子として十分
で利用できる範囲である。The sensitivity is within 15 dB from the standard, which is sufficient for use as a piezoelectric element.
以上説明したように本発明によれば、膜厚１０００八以
上の金電極で被覆した非晶質基板上に酸化亜鉛薄膜を形
成することにより、電気音響変換効率の高い圧電素子を
安定に作業できることは明らかである。As explained above, according to the present invention, by forming a zinc oxide thin film on an amorphous substrate coated with a gold electrode with a film thickness of 1000 mm or more, a piezoelectric element with high electroacoustic conversion efficiency can be stably operated. is clear.
第２図は、下部金電極の膜厚と素子の感度および酸化亜
鉛薄膜のＣ軸配向性の関係を示す特性曲線図。第２図に
おいて、
５・・・金電極の膜厚と素子の感度の関係を示す特性曲
線、６・・・金電極の膜厚と酸化亜鉛薄膜のＣ軸配向性
の関係を示す特性曲線。
第１図は、素子の構造を示す断面図。第１図において、
１・・・基板、２・・・クロムおよび金電極、３・・・
酸化亜鉛薄膜、４・・・上部電極。FIG. 2 is a characteristic curve diagram showing the relationship between the film thickness of the lower gold electrode, the sensitivity of the device, and the C-axis orientation of the zinc oxide thin film. In FIG. 2, 5... Characteristic curve showing the relationship between the film thickness of the gold electrode and the sensitivity of the element, 6... Characteristic curve showing the relationship between the film thickness of the gold electrode and the C-axis orientation of the zinc oxide thin film. FIG. 1 is a sectional view showing the structure of the element. In FIG. 1, 1...substrate, 2...chromium and gold electrode, 3...
Zinc oxide thin film, 4...upper electrode.
Claims (1)
スパッタリングにより酸化亜鉛ＺｎＯ薄膜を形成し、さ
らに上部電極を設けたことを特徴とする圧電素子。On an amorphous substrate coated with Au with a thickness of 1000 mm or more,
A piezoelectric element comprising a zinc oxide ZnO thin film formed by sputtering and further provided with an upper electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59001907A JPS60147180A (en) | 1984-01-11 | 1984-01-11 | Piezoelectric element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59001907A JPS60147180A (en) | 1984-01-11 | 1984-01-11 | Piezoelectric element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60147180A true JPS60147180A (en) | 1985-08-03 |
Family
ID=11514648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59001907A Pending JPS60147180A (en) | 1984-01-11 | 1984-01-11 | Piezoelectric element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60147180A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005244184A (en) * | 2004-01-28 | 2005-09-08 | Toshiba Corp | Thin-film piezoelectric element and method of manufacturing the thin-film piezoelectric element |
| JP2006186831A (en) * | 2004-12-28 | 2006-07-13 | Kyocera Kinseki Corp | Piezoelectric thin film device and its manufacturing method |
| US7770274B2 (en) | 2004-01-28 | 2010-08-10 | Kabushiki Kaisha Toshiba | Piezoelectric thin film device and method for manufacturing the same |
-
1984
- 1984-01-11 JP JP59001907A patent/JPS60147180A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005244184A (en) * | 2004-01-28 | 2005-09-08 | Toshiba Corp | Thin-film piezoelectric element and method of manufacturing the thin-film piezoelectric element |
| US7770274B2 (en) | 2004-01-28 | 2010-08-10 | Kabushiki Kaisha Toshiba | Piezoelectric thin film device and method for manufacturing the same |
| JP2006186831A (en) * | 2004-12-28 | 2006-07-13 | Kyocera Kinseki Corp | Piezoelectric thin film device and its manufacturing method |
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