JPH0786656A - Piezoelectric thin film element - Google Patents
Piezoelectric thin film elementInfo
- Publication number
- JPH0786656A JPH0786656A JP5193003A JP19300393A JPH0786656A JP H0786656 A JPH0786656 A JP H0786656A JP 5193003 A JP5193003 A JP 5193003A JP 19300393 A JP19300393 A JP 19300393A JP H0786656 A JPH0786656 A JP H0786656A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric
- thin film
- film
- layer
- 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.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/14—Structure thereof only for on-demand ink jet heads
- B41J2/14201—Structure of print heads with piezoelectric elements
- B41J2/14233—Structure of print heads with piezoelectric elements of film type, deformed by bending and disposed on a diaphragm
- B41J2002/14258—Multi layer thin film type piezoelectric element
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、マイクロメカニクス等
に応用される逆圧電効果により機械エネルギーを得る圧
電薄膜素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric thin film element for obtaining mechanical energy by an inverse piezoelectric effect applied to micromechanics and the like.
【０００２】[0002]
【従来の技術】従来、圧電薄膜素子の圧電層を形成する
圧電体薄膜には、酸化亜鉛（以下ＺｎＯで表わす）薄膜
が広く用いられている。ＺｎＯは、マグネトロンスパッ
タ法や蒸着法によって、条件をよくコントロールすれ
ば、良好なＣ軸配向の膜が比較的簡単に得られ、良好な
圧電性が得られることがよく知られている。又、近年、
半導体プロセス技術を背景にして、半導体を機械的構造
体として用いた、半導体圧力センサー、半導体加速度セ
ンサー及びマイクロアクチュエーター等の機械的電気素
子（マイクロメカニクス）が脚光を浴びるようになって
きた。かかる機械的電気素子の特長としては、小型で且
つ高精度の機械機構部品を提供出来ること、及び半導体
ウエハと同素材のＳｉを基板に用いている為、Ｓｉウエ
ハ上に素子と電気回路とを一体化出来ることが挙げられ
る。更に、半導体プロセスをベースに作製することで、
半導体プロセスのバッチ処理による生産性の向上を期待
することが出来る。2. Description of the Related Art Conventionally, a zinc oxide (hereinafter referred to as ZnO) thin film has been widely used as a piezoelectric thin film forming a piezoelectric layer of a piezoelectric thin film element. It is well known that if the conditions of ZnO are well controlled by a magnetron sputtering method or a vapor deposition method, a film having a good C-axis orientation can be obtained relatively easily and a good piezoelectric property can be obtained. In recent years,
With the background of semiconductor process technology, mechanical electrical elements (micromechanics) such as semiconductor pressure sensors, semiconductor acceleration sensors, and microactuators, which use semiconductors as mechanical structures, have come into the limelight. The features of such a mechanical electric element are that it is possible to provide a small and high-precision mechanical mechanism component, and since Si, which is the same material as the semiconductor wafer, is used as the substrate, the element and the electric circuit are formed on the Si wafer. It is possible to integrate them. Furthermore, by making it based on a semiconductor process,
It can be expected to improve productivity by batch processing of semiconductor processes.
【０００３】以上の様な機械的電気素子の中で、特に、
圧電体薄膜を利用したものとしてはカンチレバー型圧電
バイモルフ素子が挙げられる。これは非常に微細な動き
を制御することが可能である為、原子レベル及び分子レ
ベルで直接観察することが出来る走査型トンネル顕微鏡
（以下ＳＴＭと称す。）に応用されている。例えば、ス
タンフォード大学のクエート等により提案されたカンチ
レバー型圧電素子を用いたＳＴＭプローブが挙げられる
（ＩＥＥＥ Micro Electro Mechanical Systems、
ｐｌ８８−１９９、Ｆｅｂ．１９９０）。これは図５に
示す様に、Ｓｉウエハ基板８１の裏面を一部除去してＳ
ｉメンブレンを形成し、表面にアルミニウム（Ａｌ）８
３と酸化亜鉛（ＺｎＯ）８４の薄膜を順次積層し、バイ
モルフのカンチレバーを形成した後、裏面から反応性の
ドライエッチによりＳｉメンブレンとＳｉウエハ表面の
エッチングの保護膜（シリコン窒化膜）を除去して、Ｓ
ＴＭプローブ変位用のバイモルフカンチレバー型圧電素
子を作製している。上記の様なカンチレバーの上面自由
端部に、トンネル電流検知用マイクロティップ８２を取
り付け、圧電体薄膜ＺｎＯの逆圧電効果を利用してＸＹ
Ｚ方向に走査し、良好なＳＴＭ像を得ている。Among the above-mentioned mechanical electric elements, in particular,
A cantilever-type piezoelectric bimorph element is used as the piezoelectric thin film. Since it can control very fine movements, it is applied to a scanning tunneling microscope (hereinafter referred to as STM) that allows direct observation at the atomic level and the molecular level. For example, there is an STM probe using a cantilever type piezoelectric element proposed by Kuwait et al. Of Stanford University (IEEE Micro Electro Mechanical Systems,
pl88-199, Feb. 1990). As shown in FIG. 5, the back surface of the Si wafer substrate 81 is partially removed to remove the S
i Membrane is formed and aluminum (Al) 8 is formed on the surface.
3 and a thin film of zinc oxide (ZnO) 84 are sequentially laminated to form a bimorph cantilever, and then the Si membrane and the etching protection film (silicon nitride film) on the Si wafer surface are removed by reactive dry etching from the back surface. S
A bimorph cantilever type piezoelectric element for TM probe displacement is manufactured. A microtip 82 for detecting a tunnel current is attached to the free end of the upper surface of the cantilever as described above, and XY is formed by utilizing the inverse piezoelectric effect of the piezoelectric thin film ZnO.
A good STM image is obtained by scanning in the Z direction.
【０００４】[0004]
【発明が解決しようとする課題】従来、圧電体薄膜とし
て用いられているＺｎＯは、バルク単結晶の場合、圧電
定数ｄ31＝−５．４３ｐＣ／Ｎ、ｄ33＝１１．７ｐＣ／
Ｎと比較的高い値を持つ。これはＰＺＴ等に比べると圧
電性は低い。しかし、マイクロメカニクス等への応用を
考えた場合に、ＺｎＯはＳｉとのモノリシック化が容易
であり、この点からＺｎＯ薄膜は広く用いられている。
一般に圧電特性を有する材料は、薄膜化を行うと低い電
圧でも充分な駆動が可能であるというメリットがある。
しかし、ＺｎＯ薄膜は酸素欠損型半導体である為、抵抗
率及び絶縁耐圧が低いという問題がある。例えば、前記
した走査型トンネル顕微鏡に用いられるカンチレバー型
圧電素子の圧電体薄膜にＺｎＯを用いると、駆動させる
為の信号がトンネル電流を検出する信号にのってしま
い、クロストークを発生してしまうという問題点があ
る。又、ＺｎＯは吸水性の高い材料である為、実用化を
考えると耐久性の点から不安な面もある。従って、本発
明の目的は、上記の従来技術の問題点を解決し、抵抗率
及び絶縁耐圧が高く、且つ経時変化のない優れた圧電薄
膜素子を提供することにある。又、本発明の別の目的
は、耐久性に優れ、実用価値の高い圧電薄膜素子を提供
することにある。ZnO conventionally used as a piezoelectric thin film, in the case of a bulk single crystal, has piezoelectric constants d 31 = −5.43 pC / N, d 33 = 11.7 pC / N.
It has a relatively high value of N. This has lower piezoelectricity than PZT and the like. However, when considering application to micromechanics and the like, ZnO is easily monolithic with Si, and from this point, the ZnO thin film is widely used.
In general, a material having piezoelectric characteristics has an advantage that it can be sufficiently driven even at a low voltage by thinning it.
However, since the ZnO thin film is an oxygen-deficient semiconductor, it has a problem that the resistivity and the withstand voltage are low. For example, when ZnO is used for the piezoelectric thin film of the cantilever type piezoelectric element used in the above-mentioned scanning tunneling microscope, the signal for driving is added to the signal for detecting the tunnel current, which causes crosstalk. There is a problem. Further, since ZnO is a material having a high water absorption, there is a concern in terms of durability from the viewpoint of practical application. Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an excellent piezoelectric thin film element having a high resistivity and a high withstand voltage and no change over time. Another object of the present invention is to provide a piezoelectric thin film element having excellent durability and high practical value.
【０００５】[0005]
【課題を解決する為の手段】上記の目的は、以下の本発
明によって達成される。即ち、本発明は二発明からな
り、第一の発明は、基板表面に少なくとも下電極、圧電
体薄膜からなる圧電体層及び上電極の３層構成で形成さ
れる圧電薄膜素子において、圧電体層が窒化アルミ薄膜
及び酸化亜鉛薄膜からなる積層膜で形成されていること
を特徴とする圧電薄膜素子であり、第二の発明は、基板
表面に少なくとも下電極、下部圧電体層、中電極、上部
圧電体層及び上電極の５層構成で形成される圧電薄膜素
子において、下部圧電体層が窒化アルミ薄膜及び酸化亜
鉛薄膜からなる積層膜又は酸化亜鉛薄膜で形成され、且
つ上部圧電体層が窒化アルミ薄膜及び酸化亜鉛薄膜から
なる積層膜又は窒化アルミ薄膜で形成されていることを
特徴とする圧電薄膜素子である。The above object can be achieved by the present invention described below. That is, the present invention comprises two inventions, and the first invention is a piezoelectric thin film element formed by a three-layer structure of at least a lower electrode, a piezoelectric layer composed of a piezoelectric thin film, and an upper electrode on a substrate surface. Is a laminated film formed of an aluminum nitride thin film and a zinc oxide thin film, and a second invention is a piezoelectric thin film element, wherein the substrate surface has at least a lower electrode, a lower piezoelectric layer, a middle electrode, and an upper electrode. In a piezoelectric thin film element having a five-layer structure of a piezoelectric layer and an upper electrode, the lower piezoelectric layer is formed of a laminated film of an aluminum nitride thin film and a zinc oxide thin film or a zinc oxide thin film, and the upper piezoelectric layer is nitrided. A piezoelectric thin film element characterized by being formed of a laminated film composed of an aluminum thin film and a zinc oxide thin film or an aluminum nitride thin film.
【０００６】[0006]
【好ましい実施態様】次に好ましい実施態様を挙げて本
発明を更に詳細に説明する。本発明の第一の発明の特徴
は、圧電薄膜素子を構成する圧電体層を、窒化アルミ
（以下ＡｌＮと表わす）薄膜及びＺｎＯ薄膜からなる積
層膜で形成したことにある。又、本発明の第二の発明の
特徴は、圧電薄膜素子を構成する２層の圧電体層を、夫
々ＡｌＮ薄膜及びＺｎＯ薄膜からなる積層膜で形成する
か、一方をＡｌＮ薄膜で形成し、他方をＺｎＯ薄膜で形
成したことにある。即ち、圧電薄膜素子の圧電層をＺｎ
Ｏの圧電体薄膜にＡｌＮ薄膜を併用して形成することに
より、従来技術の問題点の解決を図ったものである。BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. The first feature of the present invention is that the piezoelectric layer forming the piezoelectric thin film element is formed of a laminated film including an aluminum nitride (hereinafter referred to as AlN) thin film and a ZnO thin film. The second feature of the present invention is that the two piezoelectric layers constituting the piezoelectric thin film element are each formed of a laminated film composed of an AlN thin film and a ZnO thin film, or one of them is formed of an AlN thin film, The other is formed by a ZnO thin film. That is, the piezoelectric layer of the piezoelectric thin film element is
By forming an AlN thin film together with an O piezoelectric thin film, the problems of the prior art are solved.
【０００７】従来、絶縁破壊は、薄膜の誘電損失による
熱的破壊に原因することが知られているが、絶縁耐圧の
低下は、抵抗率に起因する誘電損失が原因であると考え
られる。作製条件によって異なるが、マグネトロンスパ
ッタ法におけるＺｎＯ薄膜の比抵抗は、ρ＝１０5 〜１
０8 Ω・ｃｍであり、同方法におけるＡｌＮの比抵抗
は、ρ＝１０8 〜１０11Ω・ｃｍである。従って、絶縁
耐圧の向上はＡｌＮ薄膜をＺｎＯ薄膜に併用することで
解決することが出来る。更に、ＡｌＮはＺｎＯに比べて
吸水性が少なく、耐久性も高い為、実用性にも優れる。
一方、圧電性においては、ＺｎＯのｄ31＝−５．４ｐＣ
／Ｎ、ｄ33＝１１．７ｐＣ／Ｎ（バルク値）に比べてＡ
ｌＮは、ｄ31＝−２．０ｐＣ／Ｎ、ｄ33＝５ｐＣ／Ｎ程
度と、半分程度になる。一般に薄膜では、格子欠陥等に
よりバルク値よりも若干低下するのが通常であるが、Ａ
ｌＮはＺｎＯよりも圧電性が低いので、絶縁耐圧或は耐
久性を上げようとすると圧電性が低くなる為、両者のト
レードオフが重要となる。Conventionally, it has been known that dielectric breakdown is caused by thermal breakdown due to dielectric loss of a thin film, but it is considered that the decrease in withstand voltage is caused by dielectric loss due to resistivity. Although it depends on the fabrication conditions, the resistivity of the ZnO thin film in the magnetron sputtering method is ρ = 10 5 to 1
A 0 8 Ω · cm, the specific resistance of the AlN in the same method is ρ = 10 8 ~10 11 Ω · cm. Therefore, the improvement of the withstand voltage can be solved by using the AlN thin film together with the ZnO thin film. Furthermore, AlN has less water absorption and higher durability than ZnO, and is therefore highly practical.
On the other hand, in piezoelectricity, d 31 = −5.4 pC of ZnO
/ N, d 33 = 11.7 pC / N (bulk value) compared to A
1N is about half, that is, d 31 = −2.0 pC / N and d 33 = 5 pC / N. Generally, in a thin film, it is usually slightly lower than the bulk value due to lattice defects and the like.
Since the piezoelectricity of 1N is lower than that of ZnO, the piezoelectricity becomes low when the withstand voltage or durability is increased, and the trade-off between the two is important.
【０００８】[0008]
【実施例】以下、実施例を用いて本発明を具体的に詳述
する。実施例１ 本発明の第一の発明の圧電薄膜素子について、図１に示
す断面模式図に基づき説明する。図１に示す様に、本発
明の圧電薄膜素子は、基本的に、Ｓｉ基板１上に形成さ
れた下部電極２、圧電層１０及び上部電極６の３層で構
成される。そして、圧電層１０は、ＡｌＮ圧電体薄膜
３、ＺｎＯ圧電体薄膜４、ＡｌＮ圧電体薄膜５からなる
積層膜で構成されている。尚、これは例示であって、Ａ
ｌＮとＺｎＯからなる積層膜で構成されていれば、本実
施例のものに限定されずいかなるものでもよいのは勿論
である。次に、上記の様な構成の本発明の圧電薄膜素子
の作成方法について述べる。先ず、厚さ３μｍの熱酸化
膜を有するＳｉ基板１に、イオンビームスパッタ法によ
り、厚さ２ｎｍのＴｉの密着層を持つＰｔ薄膜（０．１
μｍ）を蒸着し、下部電極２を形成する。次にこの上
に、マグネトロンスパッタ法によりＡｌＮ及びＺｎＯを
夫々蒸着し、圧電体層１０を形成した。これらは、マグ
ネトロンスパッタ装置内でターゲットを交換することに
よって、以下の製膜条件で交互に積層した。マグネトロ
ンスパッタ法によるＡｌＮの蒸着条件としては、ターゲ
ットとしてＡｌを用い、基板温度２００℃、Ａｒ：Ｎ2
＝１：１の雰囲気下で、１．５Ｐａで成膜速度０．２ｎ
ｍ／ｓｅｃの条件で成膜した。又、ＺｎＯの蒸着条件と
しては、ターゲットとしてＺｎＯを用い、基板温度２０
０℃、Ａｒ：Ｏ2 ＝１：１の雰囲気下で、２．０Ｐａ、
成膜速度０．２ｎｍ／ｓｅｃの条件で成膜した。この様
な条件により良好なＣ軸配向膜が得られる。上記の条件
に従い、先ず、下部電極２の上に、ＡｌＮを膜厚０．１
μｍとなる様に蒸着してＡｌＮ圧電体薄膜３を形成した
後、この上にＺｎＯを膜厚０．３μｍとなる様に蒸着し
てＺｎＯ圧電体薄膜４を形成する。更に、ＺｎＯ圧電体
薄膜４の上に再度ＡｌＮを膜厚０．１μｍとなる様に蒸
着してＡｌＮ圧電体薄膜５を形成し、本発明の圧電体薄
膜素子の３層が積層された圧電体層１０を形成した。そ
の後、これを所望の形状にパターニングした後、上電極
５として金を真空蒸着によって膜厚０．１μｍになる様
にこの上に形成して、実施例１の圧電薄膜素子を得た。EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 A piezoelectric thin film element according to the first aspect of the present invention will be described with reference to the schematic sectional view shown in FIG. As shown in FIG. 1, the piezoelectric thin film element of the present invention is basically composed of three layers of a lower electrode 2, a piezoelectric layer 10 and an upper electrode 6 formed on a Si substrate 1. The piezoelectric layer 10 is composed of a laminated film including an AlN piezoelectric thin film 3, a ZnO piezoelectric thin film 4, and an AlN piezoelectric thin film 5. Note that this is an example, and A
It is needless to say that the structure is not limited to that of the present embodiment as long as it is composed of a laminated film composed of 1N and ZnO, and any other material may be used. Next, a method for producing the piezoelectric thin film element of the present invention having the above-mentioned structure will be described. First, a Pt thin film (0.1 nm thick) having an adhesion layer of Ti of 2 nm was formed on a Si substrate 1 having a thermal oxide film of 3 μm thick by an ion beam sputtering method.
to form the lower electrode 2. Next, AlN and ZnO were vapor-deposited on each by magnetron sputtering to form the piezoelectric layer 10. These were alternately laminated under the following film forming conditions by exchanging the target in the magnetron sputtering apparatus. As the deposition conditions of AlN by the magnetron sputtering method, Al was used as a target, the substrate temperature was 200 ° C., and Ar: N 2 was used.
= 1.5: 1 in an atmosphere of = 1: 1 at a film formation rate of 0.2n
The film was formed under the condition of m / sec. As the ZnO vapor deposition conditions, ZnO was used as a target and the substrate temperature was 20
In an atmosphere of 0 ° C. and Ar: O 2 = 1: 1, 2.0 Pa,
The film was formed under the condition of the film forming rate of 0.2 nm / sec. Under such conditions, a good C-axis alignment film can be obtained. According to the above conditions, first, AlN is deposited on the lower electrode 2 to a film thickness of 0.1.
After forming the AlN piezoelectric thin film 3 by vapor deposition so as to have a thickness of μm, ZnO is vapor-deposited thereon so as to have a thickness of 0.3 μm to form a ZnO piezoelectric thin film 4. Further, AlN is vapor-deposited again on the ZnO piezoelectric thin film 4 so as to have a film thickness of 0.1 μm to form an AlN piezoelectric thin film 5, and a piezoelectric body in which three layers of the piezoelectric thin film element of the present invention are laminated. Layer 10 was formed. After that, this was patterned into a desired shape, and then gold was formed as the upper electrode 5 by vacuum vapor deposition so as to have a film thickness of 0.1 μm, whereby a piezoelectric thin film element of Example 1 was obtained.
【０００９】比較例１ 圧電体層として、膜厚０．５μｍのＺｎＯのみからなる
圧電体薄膜を形成した以外は実施例１と同様にして、従
来のＡｌＮ層が積層されていない圧電薄膜素子を作製し
た。 Comparative Example 1 A piezoelectric thin film element in which a conventional AlN layer was not laminated was prepared in the same manner as in Example 1 except that a piezoelectric thin film made of ZnO having a film thickness of 0.5 μm was formed as the piezoelectric layer. It was made.
【００１０】上記の様にして得られた実施例１及び比較
例１の圧電薄膜素子の上電極５と下電極２に直流電圧を
加え、絶縁耐圧を調べた。更に、劣化性を調べる為に、
これらの素子を温度６０℃、湿度８０％の雰囲気下に１
週間放置し、加速試験を行った。表１に、実施例１及び
比較例１の圧電薄膜素子における各試験結果を示す。こ
の結果、実施例１で得られた本発明の圧電薄膜素子は、
比較例１の従来の圧電薄膜素子に比べ、絶縁耐圧が向上
し、更に、劣化性が少ないことが明白にわかった。A DC voltage was applied to the upper electrode 5 and the lower electrode 2 of the piezoelectric thin film elements of Example 1 and Comparative Example 1 obtained as described above, and the dielectric strength was examined. Furthermore, in order to investigate the deterioration property,
Place these elements in an atmosphere with a temperature of 60 ° C and a humidity of 80%.
After leaving it for a week, an acceleration test was performed. Table 1 shows the test results of the piezoelectric thin film elements of Example 1 and Comparative Example 1. As a result, the piezoelectric thin film element of the present invention obtained in Example 1
As compared with the conventional piezoelectric thin film element of Comparative Example 1, it was clearly found that the withstand voltage was improved and the deterioration was less.
【００１１】[0011]
【表１】 [Table 1]
【００１２】実施例２ 次に、本発明の第二の圧電薄膜素子を適用したカンチレ
バー型圧電素子の実施例について述べる。本実施例の場
合は、図２（ｃ）に示す様に、基本的に、Ｓｉ基板７１
上に形成された下部電極７４ａ、下圧電層７５、中電層
７４、上圧電層７５´及び上部電極７４ｂの５層で構成
される。そして、下圧電層７５及び上圧電層７５´は、
図３に示す様に、ＡｌＮ圧電体薄膜７５ｂ、ＺｎＯ圧電
体薄膜７５ａ、ＡｌＮ圧電体薄膜７５ｂからなる３層の
積層膜で夫々構成されている。図２に示したカンチレバ
ー型圧電素子の製造工程図に従って、カンチレバー部の
作成方法について述べる。最初に、厚さ２５０μｍのＳ
ｉ（１００）基板７１上に、ＬＰ−ＣＶＤ法によりシリ
コン窒化膜７３を厚さ０．０５μｍとなる様に積層した
後、フォトリソグラフィーによりパターニングし、エッ
チングマスクとする（図２（ａ）図示）。その後、ＫＯ
Ｈ溶液によるＳｉの異方性エッチングを行い、Ｓｉのメ
ンブレンを作製する（図２（ｂ）図示）。次に、この上
にイオンビームスパッタ法により、下電極であるＰｔ電
極７４ａを膜厚０．１μｍとなる様に積層し、パターニ
ングする。更に、下電極７４ａの上に、実施例１で用い
たと同様の条件でＲＦマグネトロンスパッタ法により、
下圧電体層７５を形成後、下圧電体層７５の上に、再度
イオンビームスパッタ法により中電極であるＰｔ電極７
４を膜厚０．１μｍとなる様に形成する。尚、下圧電体
層７５は、図３に示す様に、先ず、下電極７４ａの上に
ＡｌＮを０．１μｍ成膜して圧電体薄膜７５ｂを形成
し、その上にＺｎＯを０．３μｍ成膜して圧電体薄膜７
５ａを形成し、更にその上にＡｌＮを０．１μｍの膜厚
となる様に成膜して、順次積層して形成する。 Example 2 Next, an example of a cantilever type piezoelectric element to which the second piezoelectric thin film element of the present invention is applied will be described. In the case of this embodiment, as shown in FIG. 2C, the Si substrate 71 is basically used.
The lower electrode 74a, the lower piezoelectric layer 75, the middle electric layer 74, the upper piezoelectric layer 75 ', and the upper electrode 74b are formed on the upper electrode 74b. The lower piezoelectric layer 75 and the upper piezoelectric layer 75 'are
As shown in FIG. 3, each layer is composed of a three-layer laminated film including an AlN piezoelectric thin film 75b, a ZnO piezoelectric thin film 75a, and an AlN piezoelectric thin film 75b. A method of forming the cantilever portion will be described with reference to the manufacturing process diagram of the cantilever piezoelectric element shown in FIG. First, S with a thickness of 250 μm
A silicon nitride film 73 is deposited on the i (100) substrate 71 by LP-CVD so as to have a thickness of 0.05 μm, and then patterned by photolithography to form an etching mask (FIG. 2A). . Then KO
Anisotropic etching of Si by H solution is performed to produce a Si membrane (shown in FIG. 2B). Next, a Pt electrode 74a, which is a lower electrode, is laminated thereon by an ion beam sputtering method so as to have a film thickness of 0.1 μm, and patterned. Further, on the lower electrode 74a, by the RF magnetron sputtering method under the same conditions as used in Example 1,
After forming the lower piezoelectric layer 75, the Pt electrode 7 which is a middle electrode is again formed on the lower piezoelectric layer 75 by the ion beam sputtering method.
4 is formed to have a film thickness of 0.1 μm. In the lower piezoelectric layer 75, as shown in FIG. 3, first, AlN is deposited to a thickness of 0.1 μm on the lower electrode 74a to form a piezoelectric thin film 75b, and ZnO is deposited to a thickness of 0.3 μm. Piezoelectric thin film 7
5a is formed, and further, AlN is formed to have a film thickness of 0.1 μm and sequentially laminated.
【００１３】次に、下圧電体層７５の上に、再度イオン
ビームスパッタ法により中電極であるＰｔ電極７４を膜
厚０．１μｍとなる様に形成し、更に、この上にＲＦマ
グネトロンスパッタ法にて、上記の下圧電体層７５と同
じ構成の上圧電体層７５´を膜厚０．５μｍとなる様に
積層し、パターニングを行った。続いて、抵抗加熱法に
よってＡｕの上電極７４ｂを膜厚０．１μｍとなる様に
堆積し、パターニングを行った。又、この上部に、蒸着
法によりＰｔで形成されるトンネル電流検知用ＳＴＭマ
イクロティップ７６を作製した（図２（ｃ）図示）。最
後に、反応性イオンエッチング法により、シリコン窒化
膜を除去し、本実施例のカンチレバー型圧電素子を得た
（図２（ｄ））。得られたカンチレバー型圧電素子は矩
形で、長さ３００μｍ×幅１００μｍ厚さ約１．３μｍ
である。Next, a Pt electrode 74, which is a middle electrode, is formed again on the lower piezoelectric layer 75 by an ion beam sputtering method so as to have a film thickness of 0.1 μm, and further, an RF magnetron sputtering method is further formed thereon. Then, an upper piezoelectric layer 75 ′ having the same structure as the lower piezoelectric layer 75 was laminated to a film thickness of 0.5 μm and patterned. Then, an Au upper electrode 74b was deposited by a resistance heating method so as to have a film thickness of 0.1 μm and patterned. Further, an STM microtip 76 for detecting a tunnel current, which is formed of Pt by vapor deposition, was formed on the upper portion of the STM microtip 76 (shown in FIG. 2C). Finally, the silicon nitride film was removed by a reactive ion etching method to obtain a cantilever type piezoelectric element of this example (FIG. 2 (d)). The obtained cantilever piezoelectric element has a rectangular shape with a length of 300 μm × a width of 100 μm and a thickness of about 1.3 μm.
Is.
【００１４】比較例２ 圧電体層をＺｎＯのみを用い、下圧電体薄膜としてＺｎ
Ｏ層を０．５μｍ、上圧電体薄膜としてＺｎＯ層を０．
５μｍ成膜した以外、その他の電極構成は実施例２と同
様にして比較用のカンチレバー型圧電素子を作製した。
得られたカンチレバー型圧電素子は、実施例１と同様
に、矩形で、長さ３００μｍ×幅１００μｍ 厚さ約
１．３μｍである。 Comparative Example 2 The piezoelectric layer was made of ZnO only, and the lower piezoelectric thin film was made of ZnO.
The O layer is 0.5 μm, and the ZnO layer as an upper piezoelectric thin film is 0.1 μm.
A comparative cantilever-type piezoelectric element was manufactured in the same manner as in Example 2 except that the film was formed to a thickness of 5 μm.
The obtained cantilever-type piezoelectric element was rectangular and had a length of 300 μm × width of 100 μm and a thickness of about 1.3 μm, as in Example 1.
【００１５】図３は、実施例２のカンチレバー型圧電素
子の断面図であるが、７４ａは下電極、７５ｂはＡｌＮ
圧電体薄膜、７５ａはＺｎＯ圧電体薄膜で、７４は中電
極、７４ｂは上電極、７４ｃはトンネル電流引き出し
線、及び７６はトンネル電流検知用ＳＴＭプローブであ
る。このカンチレバー型圧電素子は、上電極７４ｂと下
電極７４ａとを短絡させ、中電極７４に電圧を印加する
と逆圧電効果により屈曲運動を始める。FIG. 3 is a cross-sectional view of the cantilever type piezoelectric element of Example 2, in which 74a is a lower electrode and 75b is AlN.
The piezoelectric thin film, 75a is a ZnO piezoelectric thin film, 74 is a middle electrode, 74b is an upper electrode, 74c is a tunnel current extraction line, and 76 is a tunnel current detection STM probe. In this cantilever type piezoelectric element, when the upper electrode 74b and the lower electrode 74a are short-circuited and a voltage is applied to the middle electrode 74, the bending movement starts due to the inverse piezoelectric effect.
【００１６】通常ＳＴＭにこのカンチレバー型圧電素子
を用いる場合には、トンネル電流検知用ＳＴＭプローブ
７６でトンネル電流を検知するが、トンネル電流として
は、例えば、１ｐＡから１０ｎＡとかなり低い電流を検
知する必要がある。この為、中電極７４、トンネル電流
検知用ＳＴＭマイクロティップ７６及びトンネル電流引
き出し線７４ｃは、等電位にするのが一般的である。上
記の結線方法の場合は、圧電素子を駆動する電圧によっ
て中電極７４からのリーク電流がトンネル電流検知用Ｓ
ＴＭプローブ７６にのらない為、通常この方法が用いら
れる。しかし、上電極７４ｂとトンネル電流引き出し線
７４ｃとの電位差が異なるので、この間の表面リークが
問題となる。例えば、カンチレバー型圧電素子を駆動す
るのに、通常±１．５Ｖの直流電圧が（上−下）電極と
中電極間にかけられる。この場合、１０ｐＡ程度のトン
ネル電流値がモニター出来るようにするには、最低でも
駆動電圧によるリーク電流が０．５ｐＡ程度に納まるよ
うにしなければならない。この場合には、上電極７４ｂ
とトンネル電流引き出し線７４ｃの直流抵抗として３Ｔ
Ω以上の高抵抗値が必要となる。これに対し、本発明の
カンチレバー型圧電素子においては、圧電層にＡｌＮが
用いられている為、この高抵抗値を容易に達成すること
が出来る。When this cantilever type piezoelectric element is normally used in the STM, the tunnel current is detected by the STM probe 76 for detecting the tunnel current, but as the tunnel current, it is necessary to detect a considerably low current of 1 pA to 10 nA. There is. Therefore, the middle electrode 74, the tunnel current detection STM microtip 76, and the tunnel current extraction line 74c are generally set to the same potential. In the case of the above wiring method, the leak current from the middle electrode 74 is changed to the tunnel current detection S by the voltage for driving the piezoelectric element.
This method is usually used because it does not fit on the TM probe 76. However, since the potential difference between the upper electrode 74b and the tunnel current lead-out line 74c is different, surface leakage during this time becomes a problem. For example, to drive a cantilever type piezoelectric element, a direct current voltage of ± 1.5 V is usually applied between the (upper-lower) electrode and the middle electrode. In this case, in order to be able to monitor the tunnel current value of about 10 pA, the leak current due to the driving voltage must be at least about 0.5 pA. In this case, the upper electrode 74b
And 3T as the DC resistance of the tunnel current lead wire 74c
A high resistance value of Ω or more is required. On the other hand, in the cantilever type piezoelectric element of the present invention, since AlN is used for the piezoelectric layer, this high resistance value can be easily achieved.
【００１７】表２は、実施例２のカンチレバー型圧電素
子と、比較例２の圧電層にＺｎＯのみを用いた従来のカ
ンチレバー型圧電素子との比較を示したものである。表
２から、実施例２の本発明のカンチレバー型圧電素子に
よれば、従来のＺｎＯのみのカンチレバー型圧電素子に
比べ、圧電性による駆動の絶対変位量は低下するけれど
も、ＳＴＭ作動時においてリーク電流が少なく、且つ経
時変化も少ない優れたカンチレバー型圧電素子が得られ
る。更に、本発明のカンチレバー型圧電素子は、所望の
固有振動数並びに変位量を必要とする場合には、カンチ
レバー型圧電素子の長さを変えたり、圧電層を形成する
圧電体薄膜の厚さを変える等の設計により随時対応する
ことが出来る。Table 2 shows a comparison between the cantilever type piezoelectric element of Example 2 and the conventional cantilever type piezoelectric element of Comparative Example 2 using only ZnO for the piezoelectric layer. From Table 2, according to the cantilever type piezoelectric element of the present invention of Example 2, although the absolute displacement amount of driving by piezoelectricity is reduced as compared with the conventional cantilever type piezoelectric element only of ZnO, the leakage current during STM operation is small. It is possible to obtain an excellent cantilever-type piezoelectric element which has a small amount and a small change with time. Further, the cantilever-type piezoelectric element of the present invention, when the desired natural frequency and the amount of displacement are required, the length of the cantilever-type piezoelectric element is changed or the thickness of the piezoelectric thin film forming the piezoelectric layer is changed. It can be dealt with at any time by changing the design.
【００１８】[0018]
【表２】 [Table 2]
【００１９】実施例３ 次に、本発明の第二の発明の圧電薄膜素子を適用したカ
ンチレバー型圧電素子の別の実施例について述べる。本
実施例の場合は、圧電体層の構成が異なる以外は実施例
２と同様の構成を有する。図４に本実施例のカンチレバ
ー型圧電素子の断面図を示したが、実施例２とは異な
り、下圧電体層７５ａを、圧電性の高いＺｎＯの０．５
μｍの圧電薄膜を用いて形成し、上圧電体層７５ｂを、
抵抗率の高いＡｌＮの０．５μｍの圧電薄膜を使用して
形成されている。上記の実施例３において得られたカン
チレバー型圧電素子も、実施例２と同様の方法で評価し
たところ、実施例２のカンチレバー型圧電素子と等価な
優れた性能が得られた。 Embodiment 3 Next, another embodiment of the cantilever type piezoelectric element to which the piezoelectric thin film element of the second invention of the present invention is applied will be described. This example has the same configuration as that of Example 2 except that the configuration of the piezoelectric layer is different. FIG. 4 shows a cross-sectional view of the cantilever type piezoelectric element of the present embodiment. Unlike the second embodiment, the lower piezoelectric layer 75a is formed of ZnO 0.5 having high piezoelectricity.
The upper piezoelectric layer 75b is formed by using a piezoelectric thin film of μm,
It is formed by using a 0.5 μm piezoelectric thin film of AlN having a high resistivity. The cantilever-type piezoelectric element obtained in Example 3 was evaluated in the same manner as in Example 2, and as a result, excellent performance equivalent to that of the cantilever-type piezoelectric element in Example 2 was obtained.
【００２０】[0020]
【発明の効果】以上説明した様に、本発明の圧電薄膜素
子は、抵抗率及び絶縁耐圧が高く、且つ経時変化がない
優れた特性を有する。又、本発明の圧電薄膜素子は、耐
久性に優れ、実用価値が高い。更に、本発明のカンチレ
バー型圧電素子によれば、良好なＳＴＭ像が得られ実用
価値が高い。As described above, the piezoelectric thin film element of the present invention has high resistivity and withstand voltage, and has excellent characteristics that it does not change with time. Moreover, the piezoelectric thin film element of the present invention has excellent durability and high practical value. Further, according to the cantilever type piezoelectric element of the present invention, a good STM image can be obtained, and the practical value is high.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の圧電薄膜素子の概念図である。FIG. 1 is a conceptual diagram of a piezoelectric thin film element of the present invention.
【図２】本発明のカンチレバー型圧電素子の製造工程を
示す図である。FIG. 2 is a diagram showing a manufacturing process of the cantilever type piezoelectric element of the present invention.
【図３】本発明のカンチレバー型圧電素子の断面概念図
である。FIG. 3 is a conceptual sectional view of a cantilever type piezoelectric element of the present invention.
【図４】本発明のカンチレバー型圧電素子の斜視図であ
る。FIG. 4 is a perspective view of a cantilever type piezoelectric element of the present invention.
１、７１、８１：Ｓｉ基板 ２、７４ａ：下電極 ３、５、７５ｂ、８３：ＡｌＮ圧電体薄膜 ４、７５ａ、８４：ＺｎＯ圧電体薄膜 ６、７４ｂ：上電極 １０：圧電体層 ７３：シリコン窒化膜 ７４：中電極 ７４ｃ：トンネル電流引き出し電極 ７５：下圧電体層 ７５´：上圧電体層 ７６：トンネル電流検知用ＳＴＭプローブ ８２：トンネル電流検知用マイクロティップ 1, 71, 81: Si substrate 2, 74a: lower electrode 3, 5, 75b, 83: AlN piezoelectric thin film 4, 75a, 84: ZnO piezoelectric thin film 6, 74b: upper electrode 10: piezoelectric layer 73: silicon Nitride film 74: Middle electrode 74c: Tunnel current extraction electrode 75: Lower piezoelectric layer 75 ': Upper piezoelectric layer 76: STM probe for tunnel current detection 82: Microtip for tunnel current detection
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成５年１２月２２日[Submission date] December 22, 1993
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】図面の簡単な説明[Name of item to be corrected] Brief description of the drawing
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の圧電薄膜素子の概念図である。FIG. 1 is a conceptual diagram of a piezoelectric thin film element of the present invention.
【図２】本発明のカンチレバー型圧電素子の製造工程を
示す図である。FIG. 2 is a diagram showing a manufacturing process of the cantilever type piezoelectric element of the present invention.
【図３】本発明のカンチレバー型圧電素子の断面概念図
である。FIG. 3 is a conceptual sectional view of a cantilever type piezoelectric element of the present invention.
【図４】本発明のカンチレバー型圧電素子の断面概念図
である。FIG. 4 is a conceptual sectional view of a cantilever type piezoelectric element of the present invention.
【図５】本発明のカンチレバー型圧電素子の斜視図であ
る。FIG. 5 is a perspective view of a cantilever type piezoelectric element of the present invention.
【符号の説明】 １、７１、８１：Ｓｉ基板 ２、７４ａ：下電極 ３、５、７５ｂ、８３：ＡｌＮ圧電体薄膜 ４、７５ａ、８４：ＺｎＯ圧電体薄膜 ６、７４ｂ：上電極 １０：圧電体層 ７３：シリコン窒化膜 ７４：中電極 ７４ｃ：トンネル電流引き出し電極 ７５：下圧電体層 ７５´：上圧電体層 ７６：トンネル電流検知用ＳＴＭプローブ ８２：トンネル電流検知用マイクロティップ[Description of Reference Signs] 1, 71, 81: Si substrate 2, 74a: Lower electrode 3, 5, 75b, 83: AlN piezoelectric thin film 4, 75a, 84: ZnO piezoelectric thin film 6, 74b: Upper electrode 10: Piezoelectric Body layer 73: Silicon nitride film 74: Middle electrode 74c: Tunnel current extraction electrode 75: Lower piezoelectric layer 75 ': Upper piezoelectric layer 76: STM probe for tunnel current detection 82: Microtip for tunnel current detection
───────────────────────────────────────────────────── フロントページの続き (72)発明者 岡村 好真 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 高松 修 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 柳沢 芳浩 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 中山 優 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshimasa Okamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Osamu Takamatsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Yoshihiro Yanagisawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yu Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.
Claims (2)
膜からなる圧電体層及び上電極の３層構成で形成される
圧電薄膜素子において、圧電体層が窒化アルミ薄膜及び
酸化亜鉛薄膜からなる積層膜で形成されていることを特
徴とする圧電薄膜素子。1. A piezoelectric thin film element having a three-layer structure of at least a lower electrode, a piezoelectric layer made of a piezoelectric thin film, and an upper electrode on a substrate surface, wherein the piezoelectric layer is a laminate of an aluminum nitride thin film and a zinc oxide thin film. A piezoelectric thin film element formed of a film.
体層、中電極、上部圧電体層及び上電極の５層構成で形
成される圧電薄膜素子において、下部圧電体層が窒化ア
ルミ薄膜及び酸化亜鉛薄膜からなる積層膜又は酸化亜鉛
薄膜で形成され、且つ上部圧電体層が窒化アルミ薄膜及
び酸化亜鉛薄膜からなる積層膜又は窒化アルミ薄膜で形
成されていることを特徴とする圧電薄膜素子。2. In a piezoelectric thin film element having a five-layer structure of at least a lower electrode, a lower piezoelectric layer, a middle electrode, an upper piezoelectric layer and an upper electrode on a substrate surface, the lower piezoelectric layer is an aluminum nitride thin film and an oxide film. A piezoelectric thin film element formed by a laminated film made of a zinc thin film or a zinc oxide thin film, and the upper piezoelectric layer being formed by a laminated film made of an aluminum nitride thin film and a zinc oxide thin film or an aluminum nitride thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5193003A JPH0786656A (en) | 1993-07-09 | 1993-07-09 | Piezoelectric thin film element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5193003A JPH0786656A (en) | 1993-07-09 | 1993-07-09 | Piezoelectric thin film element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0786656A true JPH0786656A (en) | 1995-03-31 |
Family
ID=16300596
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5193003A Pending JPH0786656A (en) | 1993-07-09 | 1993-07-09 | Piezoelectric thin film element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0786656A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1365457A2 (en) * | 2002-05-24 | 2003-11-26 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film type actuator and method for manufacturing the same |
| WO2012105514A1 (en) * | 2011-01-31 | 2012-08-09 | 株式会社ミクニ | Pressure sensor element |
-
1993
- 1993-07-09 JP JP5193003A patent/JPH0786656A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1365457A2 (en) * | 2002-05-24 | 2003-11-26 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film type actuator and method for manufacturing the same |
| EP1365457A3 (en) * | 2002-05-24 | 2006-02-01 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive film type actuator and method for manufacturing the same |
| WO2012105514A1 (en) * | 2011-01-31 | 2012-08-09 | 株式会社ミクニ | Pressure sensor element |
| JP2012159374A (en) * | 2011-01-31 | 2012-08-23 | Iwate Industrial Research Center | Pressure sensor element |
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