JPH0762235B2 - Method of manufacturing ferroelectric thin film - Google Patents
Method of manufacturing ferroelectric thin filmInfo
- Publication number
- JPH0762235B2 JPH0762235B2 JP62251038A JP25103887A JPH0762235B2 JP H0762235 B2 JPH0762235 B2 JP H0762235B2 JP 62251038 A JP62251038 A JP 62251038A JP 25103887 A JP25103887 A JP 25103887A JP H0762235 B2 JPH0762235 B2 JP H0762235B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- ferroelectric thin
- sputtering
- ferroelectric
- polarization
- 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.)
- Expired - Lifetime
Links
- 239000010409 thin film Substances 0.000 title claims description 30
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000000203 mixture Substances 0.000 claims description 11
- 238000004544 sputter deposition Methods 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 3
- 230000010287 polarization Effects 0.000 description 20
- 239000010408 film Substances 0.000 description 7
- 230000002269 spontaneous effect Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910020684 PbZr Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical group [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000005477 sputtering target Methods 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Radiation Pyrometers (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は焦電型赤外線検出素子、圧電素子、電気光学素
子に用いられる強誘電体薄膜の製造方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ferroelectric thin film used for a pyroelectric infrared detecting element, a piezoelectric element, and an electro-optical element.
従来の技術 強誘電体のエレクトロニクス分野における応用は、赤外
線検出素子、圧電素子、光変調素子、メモリー素子など
さまざまなものがある。近年の半導体技術の進歩による
電子部品の小型化にともない、強誘電体素子も薄膜化が
進みつつある。2. Description of the Related Art Ferroelectrics have various applications in the electronics field, such as infrared detection elements, piezoelectric elements, light modulation elements, and memory elements. Along with the recent miniaturization of electronic parts due to the progress of semiconductor technology, the thickness of ferroelectric elements is also becoming thinner.
ところで、強誘電体の自発分極Psの変化を出力として取
り出す、例えば焦電型赤外線検出素子や圧電素子等で
は、強誘電体材料のPsが一方向に揃っている時、最も大
きい出力が得られる。By the way, the change in the spontaneous polarization Ps of the ferroelectric substance is taken out as an output. For example, in a pyroelectric infrared detection element or a piezoelectric element, the largest output is obtained when the Ps of the ferroelectric material is aligned in one direction. .
発明が解決しようとする問題点 現在、赤外線検出素子や圧電素子等に用いられている強
誘電体磁器は多結晶体であり、結晶軸の配列に方向性は
無く、従って自発分極Psもでたら目に配列している。エ
ピタキシャル強誘電体薄膜、配向性強誘電体薄膜は結晶
の分極軸は揃っているが、電気的な自発分極Psは180゜
ドメインを作り交互に配列している。そこで、これら材
料を上述のようなエレクトロニクス素子として用いる場
合、材料に高電界（〜100kV/cm）を印加してPsの向きを
揃える分極処理が必要である。Problems to be Solved by the Invention Currently, the ferroelectric porcelain used for the infrared detection element, the piezoelectric element, etc. is a polycrystalline body, and there is no directionality in the arrangement of the crystal axes, so that the spontaneous polarization Ps also appears. Arranged in the eyes. The epitaxial ferroelectric thin film and the oriented ferroelectric thin film have the crystal polarization axes aligned, but the electric spontaneous polarization Ps forms 180 ° domains and is alternately arranged. Therefore, when these materials are used as an electronic device as described above, it is necessary to apply a high electric field (-100 kV / cm) to the materials to perform polarization treatment to align the Ps directions.
また、PbTiO3・PZT・PLZTなどの薄膜の作製に関しては
多くの報告があるが、それらの強誘電相の領域の薄膜に
ついて、その分極軸であるｃ軸に配向した薄膜、自発分
極までも一方向に配向した薄膜の製造方法については全
く解明されていない。In addition, although there are many reports on the production of thin films of PbTiO 3 , PZT, PLZT, etc., thin films oriented in the c-axis, which is the polarization axis, of these thin films in the region of the ferroelectric phase are also reported. The method of manufacturing a thin film oriented in the direction has not been clarified at all.
強誘電体材料に高電界を印加してPsを揃える方法では次
のような問題点が生じる。The following problems occur in the method of aligning Ps by applying a high electric field to the ferroelectric material.
（１）分極処理により絶縁破壊が生ずる場合があり、歩
留まりが下がる。(1) Dielectric breakdown may occur due to the polarization treatment, which lowers the yield.
（２）高分解能アレイ素子の様に多くの微小素子が高密
度に配列しているものでは、それらを均一に分極するこ
とが困難である。(2) It is difficult to uniformly polarize many minute elements arranged in high density such as a high resolution array element.
（３）半導体デバイス上に強誘電体薄膜を形成した集積
化デバイスでは、分極処理そのものが不可能な場合があ
る。(3) In an integrated device in which a ferroelectric thin film is formed on a semiconductor device, polarization treatment itself may not be possible.
問題点を解決するための手段 化学式がPb（Zr1-xTix）O3である強誘電体薄膜をスパッ
タリング法により作製する際、スパッタリングターゲッ
トとして組成式｛（１−Ｙ）Pb（Zr1-xTix）03＋Y Pb
0｝において、Ｙが0.05〜0.4の範囲にある材料を用い
て、スパッタリングする。Means for Solving Problems When a ferroelectric thin film whose chemical formula is Pb (Zr 1-x Ti x ) O 3 is prepared by a sputtering method, a composition formula {(1-Y) Pb (Zr 1 -x Ti x ) 0 3 + Y Pb
In 0}, sputtering is performed using a material having Y in the range of 0.05 to 0.4.
作用 上記のような製造方法による強誘電体薄膜においては、
Psが既に一方向に揃った自然分極が得られ、分極処理を
おこなう必要が無く、歩留まり良く、高性能の強誘電体
薄膜が実現できる。Action In the ferroelectric thin film produced by the above manufacturing method,
A natural polarization in which Ps is already aligned in one direction is obtained, and it is not necessary to perform polarization treatment, and it is possible to realize a high-performance ferroelectric thin film with high yield.
実施例 （100）でへき開し鏡面研磨したMgO単結晶を基板とし、
下部電極として膜厚0.2μｍのPt薄膜をスパッタリング
により形成した。スパッタガスはAr−O2混合ガスであ
る。ついで、強誘電体薄膜Pb（Zr1-XTiX）O3（PZT）を
１〜４μｍ成長させた。方法は高周波マグネトロンスパ
ッタ法で、ArとO2の混合ガスを用い、スパッタリングタ
ーゲットは、｛（１−Ｙ）・PbZr1-XTiO3＋Y.PbO｝の粉
末である。表１に代表的なスパッタリング条件を示す。Using the MgO single crystal cleaved and mirror-polished in Example (100) as a substrate,
As the lower electrode, a Pt thin film having a film thickness of 0.2 μm was formed by sputtering. The sputtering gas is an Ar-O 2 mixed gas. Then, a ferroelectric thin film Pb (Zr 1-X Ti X ) O 3 (PZT) was grown to 1 to 4 μm. The method is a high frequency magnetron sputtering method, a mixed gas of Ar and O 2 is used, and the sputtering target is powder of {(1-Y) · PbZr 1-X TiO 3 + Y.PbO}. Table 1 shows typical sputtering conditions.
ついでこの薄膜上に上部電極を設けて、誘電特性を測定
した。 Then, an upper electrode was provided on this thin film, and the dielectric properties were measured.
第１図に、組成の異なるPZT薄膜のＸ線回折パターンを
示す。ペロブスカイト構造の（001）と（100）反射、及
びその高次の反射のみ観察される。また（001）反射の
強度が（100）のそれと比べて著しく大きいのでｃ軸配
向膜であることがわかる。ｃ軸配向率αを次の式で定義
する。FIG. 1 shows X-ray diffraction patterns of PZT thin films having different compositions. Only the (001) and (100) reflections of the perovskite structure and their higher orders are observed. Further, since the intensity of (001) reflection is significantly higher than that of (100), it can be seen that the film is a c-axis oriented film. The c-axis orientation rate α is defined by the following formula.
α＝I(001)/｛I(001)＋I(100)｝ ここでI(001)、およびI(100)はそれぞれ（001）と（10
0）反射の回折強度を表す。なお、組成はＸ線マイクロ
アナライザーで解析した結果、ターゲットとほぼ同じで
あった。α = I (001) / {I (001) + I (100) } where I (001) and I (100) are (001) and (10
0) Indicates the diffraction intensity of reflection. The composition was almost the same as the target as a result of analysis with an X-ray microanalyzer.
ｃ軸配向率α及び結晶性はスパッタリング条件である成
膜速度・スパッタリングガス・ガス圧・基板温度・ター
ゲットにより変化することが明確となった。It has been clarified that the c-axis orientation rate α and the crystallinity change depending on the sputtering conditions such as film formation rate, sputtering gas, gas pressure, substrate temperature, and target.
第２図はｃ軸配向率αと成膜速度との関係を示す。図よ
り成膜速度が速くなるとｃ軸配向率αは低下する。ター
ゲットのPbOの量:Yは、0.2〜0.3のとき、ｃ軸配向率α
及びI(001)はほぼ最大となる。また、基板温度:Tが575
〜650℃のとき、ｃ軸配向率αは高い値を示す。第３図
は、ガス圧を変えたときｃ軸配向率α及びI(001)の変化
の様子を示す。但し基板温度:T＝600℃のときである。FIG. 2 shows the relationship between the c-axis orientation rate α and the film formation rate. As shown in the figure, the c-axis orientation rate α decreases as the deposition rate increases. Target PbO amount: When Y is 0.2 to 0.3, c-axis orientation rate α
And I (001) are almost maximum. Also, the substrate temperature: T is 575
When the temperature is up to 650 ° C, the c-axis orientation rate α shows a high value. FIG. 3 shows how the c-axis orientation rate α and I (001) change when the gas pressure is changed. However, when the substrate temperature: T = 600 ° C.
ガス圧が増加すると、ｃ軸配向率αは低下するととも
に、組成Pb/Ti比も低下することが明確になった。した
がって、連続して同じターゲットを使用する場合、徐々
にガス圧を下げていくことがストイキオメトリな薄膜を
作製する重要な要素となる。It became clear that as the gas pressure increases, the c-axis orientation rate α decreases and the composition Pb / Ti ratio also decreases. Therefore, when the same target is continuously used, gradually decreasing the gas pressure is an important factor for producing a stoichiometric thin film.
以上の結果をもとにして、組成0.46＜ｘ＜１の範囲でｃ
軸配向率αが97％以上のPZT薄膜が得られるようになっ
た。Based on the above results, c in the range of composition 0.46 <x <1
A PZT thin film having an axial orientation rate α of 97% or more can be obtained.
次に、ｃ軸配向率が高いPZT薄膜の焦電係数：γ及び誘
電率：εを測定した。第４図に組成Ｘと焦電係数及び誘
電率との関係を示す。誘電率はそれぞれの組成でセラミ
クスと同等の値を示した。分極処理をしなくても焦電電
流が検出され、焦電係数は4.5x10-8C/cm2K程度の大きな
値が測定できた。この焦電係数の値は、200℃で100kV/c
m印加して分極処理を行ったPbTiO3セラミクス（γ＝1.8
x10-8C/cm2K）とくらべてかなり大きい。このことは分
極Psが既に一方向に揃った自然分極が得られていること
を意味している。なおPZTは組成が0.46＜Ｘ＜１の範囲
で結晶構造は正方晶系で、ｃ軸が分極軸である。また、
分極処理（200℃で100kV/cm210分印加）を行なった後測
定した結果、配向率が高い場合、分極処理前後で焦電係
数及び誘電率の値はほとんど変化しなかった。Next, the pyroelectric coefficient: γ and the dielectric constant: ε of the PZT thin film having a high c-axis orientation rate were measured. FIG. 4 shows the relationship between the composition X and the pyroelectric coefficient and dielectric constant. The permittivity of each composition showed the same value as that of ceramics. Pyroelectric current was detected even without polarization treatment, and a large pyroelectric coefficient of 4.5x10 -8 C / cm 2 K could be measured. The value of this pyroelectric coefficient is 100 kV / c at 200 ° C.
PbTiO 3 ceramics (γ = 1.8
x10 -8 C / cm 2 K). This means that the natural polarization in which the polarization Ps is already aligned in one direction has already been obtained. The composition of PZT is tetragonal in the composition range of 0.46 <X <1, and the c-axis is the polarization axis. Also,
As a result of measurement after polarization treatment (applying 100 kV / cm 2 for 10 minutes at 200 ° C.), when the orientation ratio was high, the values of pyroelectric coefficient and dielectric constant hardly changed before and after the polarization treatment.
以上述べたとおり、本実施例で作製したPZT薄膜では、
薄膜作製時に十分にｃ軸に配向しておれば分極処理を行
わなくても自発分極が揃っている。As described above, in the PZT thin film produced in this example,
If the film is sufficiently oriented along the c-axis during thin film production, spontaneous polarization is uniform even without polarization treatment.
本実施例で作製した強誘電体薄膜をデバイスとして利用
する場合、全く分極処理を行わなくても大きな出力が取
り出せる。これは焦電型赤外線センサばかりでなく圧電
素子、電気光学素子等においても有用である。When the ferroelectric thin film produced in this example is used as a device, a large output can be obtained without any polarization treatment. This is useful not only in the pyroelectric infrared sensor but also in piezoelectric elements, electro-optical elements and the like.
発明の効果 本発明によれば、製造される強誘電体薄膜は、分極処理
が不要であり、また特性も優れていて、作製も容易であ
るから、実用的にきわめて有効である。EFFECTS OF THE INVENTION According to the present invention, the ferroelectric thin film to be manufactured does not require polarization treatment, has excellent characteristics, and is easy to manufacture. Therefore, it is practically very effective.
第１図は発明の一実施例における強誘電体薄膜のＸ線回
折パターンを示す図、第２図は本発明の一実施例に於け
る強誘電体薄膜のｃ軸配向率と成膜速度との関係を示す
グラフ、第３図はｃ軸配向率及び（001）強度とガス圧
との関係を示す図、第４図は組成と焦電係数及び誘電率
の関係を示す図である。FIG. 1 is a diagram showing an X-ray diffraction pattern of a ferroelectric thin film in one embodiment of the invention, and FIG. 2 is a c-axis orientation ratio and a film formation rate of the ferroelectric thin film in one embodiment of the present invention. FIG. 3 is a graph showing the relationship between the c-axis orientation ratio and (001) intensity and gas pressure, and FIG. 4 is a graph showing the relationship between composition, pyroelectric coefficient and dielectric constant.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ０１Ｊ 1/02 Ｙ 8803−2Ｇ Ｈ０１Ｌ 41/187 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI technical display location G01J 1/02 Y 8803-2G H01L 41/187
Claims (3)
薄膜をスパッタリング法により作製する際、スパッタリ
ングターゲットとして組成式｛（１−Ｙ）Pb（Zr1-xT
ix）03＋Y Pb0｝において、Ｙが0.05〜0.4の範囲にある
材料を用いることを特徴とする強誘電体薄膜の製造方
法。1. When a ferroelectric thin film having a chemical formula of Pb (Zr 1-x Ti x ) O 3 is prepared by a sputtering method, a composition formula {(1-Y) Pb (Zr 1-x T
i x ) 0 3 + Y Pb0}, wherein a material in which Y is in the range of 0.05 to 0.4 is used.
する際、基板温度を550〜675゜Ｃの範囲にして作製する
事を特徴とする特許請求の範囲第１項記載の強誘電体薄
膜の製造方法。2. The method for producing a ferroelectric thin film according to claim 1, wherein the substrate temperature is set in the range of 550 to 675 ° C. when the ferroelectric thin film is produced by sputtering. Method.
する際、スパッタリングガス圧を3Paより低くすること
を特徴とする特徴とする特許請求の範囲第１項記載の強
誘電体薄膜の製造方法。3. The method for producing a ferroelectric thin film according to claim 1, wherein the sputtering gas pressure is lower than 3 Pa when the ferroelectric thin film is produced by sputtering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62251038A JPH0762235B2 (en) | 1987-10-05 | 1987-10-05 | Method of manufacturing ferroelectric thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62251038A JPH0762235B2 (en) | 1987-10-05 | 1987-10-05 | Method of manufacturing ferroelectric thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0196368A JPH0196368A (en) | 1989-04-14 |
| JPH0762235B2 true JPH0762235B2 (en) | 1995-07-05 |
Family
ID=17216691
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62251038A Expired - Lifetime JPH0762235B2 (en) | 1987-10-05 | 1987-10-05 | Method of manufacturing ferroelectric thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0762235B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2614353B2 (en) * | 1990-08-13 | 1997-05-28 | シャープ株式会社 | Method for producing ferroelectric composite oxide containing Pb |
| JP2688872B2 (en) * | 1992-03-30 | 1997-12-10 | アネルバ株式会社 | Method for producing PZT thin film and sputtering apparatus |
| US5814923A (en) * | 1994-12-27 | 1998-09-29 | Seiko Epson Corporation | Piezoelectric thin-film device, process for producing the same, and ink jet recording head using said device |
| JP4866379B2 (en) * | 2008-02-27 | 2012-02-01 | 日信工業株式会社 | Brake hydraulic pressure control device for bar handle vehicle |
| JP2010084160A (en) * | 2008-09-29 | 2010-04-15 | Fujifilm Corp | Film deposition method of lead-containing perovskite-type oxide film, piezoelectric device, and liquid ejecting device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59121119A (en) * | 1982-12-28 | 1984-07-13 | Matsushita Electric Ind Co Ltd | Production of thin film of ferroelectric material |
| JPS61292384A (en) * | 1985-06-19 | 1986-12-23 | Toyota Motor Corp | Piezoelectric ceramic compound |
-
1987
- 1987-10-05 JP JP62251038A patent/JPH0762235B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0196368A (en) | 1989-04-14 |
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