JPH08253323A - Ferroelectric thin film, target for forming the same and production of ferroelectric thin film usint the same - Google Patents
Ferroelectric thin film, target for forming the same and production of ferroelectric thin film usint the sameInfo
- Publication number
- JPH08253323A JPH08253323A JP7079533A JP7953395A JPH08253323A JP H08253323 A JPH08253323 A JP H08253323A JP 7079533 A JP7079533 A JP 7079533A JP 7953395 A JP7953395 A JP 7953395A JP H08253323 A JPH08253323 A JP H08253323A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- ferroelectric thin
- target
- same
- forming
- 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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Links
- 239000010409 thin film Substances 0.000 title claims abstract description 45
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000000203 mixture Substances 0.000 claims abstract description 25
- 239000013078 crystal Substances 0.000 claims abstract description 11
- 239000000126 substance Substances 0.000 claims abstract description 10
- 239000000843 powder Substances 0.000 claims abstract description 8
- 238000004544 sputter deposition Methods 0.000 claims abstract description 7
- 229910052779 Neodymium Inorganic materials 0.000 claims abstract description 6
- 229910052772 Samarium Inorganic materials 0.000 claims abstract description 6
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [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 claims abstract description 3
- 239000000758 substrate Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 7
- 150000002500 ions Chemical class 0.000 abstract description 17
- 229910052726 zirconium Inorganic materials 0.000 abstract description 9
- 229910052688 Gadolinium Inorganic materials 0.000 abstract description 2
- 229910003781 PbTiO3 Inorganic materials 0.000 abstract 1
- 239000010408 film Substances 0.000 description 16
- 239000000463 material Substances 0.000 description 10
- 230000010287 polarization Effects 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 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
- 239000011812 mixed powder Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
Landscapes
- Radiation Pyrometers (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Inorganic Insulating Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は例えば焦電型赤外線検出
素子や圧電素子もしくは電気光学素子などに用いる強誘
電体薄膜及びその形成用ターゲット並びにそれを用いた
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 ferroelectric thin film for use in, for example, a pyroelectric infrared detecting element, a piezoelectric element or an electro-optical element, a target for forming the same, and a method of manufacturing a ferroelectric thin film using the same. Is.
【０００２】[0002]
【従来の技術】一般に強誘電体とは、電場がなくても物
質自体の中に自発分極が存在し、外部電場によってその
向きを反転できる性質を有する物質である。この性質を
利用して焦電型赤外線検出素子や圧電素子もしくは電気
光学素子などの種々の電子デバイスが製造されている。
例えば、焦電型赤外線検出素子は、強誘電体の自発分極
の温度変化を出力として取り出す応用例の１つである。2. Description of the Related Art Generally, a ferroelectric substance is a substance having a property that spontaneous polarization exists in the substance itself without an electric field and its direction can be reversed by an external electric field. Utilizing this property, various electronic devices such as a pyroelectric infrared detection element, a piezoelectric element, or an electro-optical element are manufactured.
For example, a pyroelectric infrared detection element is one of the application examples in which the temperature change of the spontaneous polarization of a ferroelectric substance is taken out as an output.
【０００３】近年、侵入警報機や火災報知器、医療用や
環境環視用の熱像解析装置等の多くの製品に利用されて
いる赤外線検出器の需要が増大し、安価で高性能な赤外
線センサーの開発が急がれている。In recent years, there has been an increasing demand for infrared detectors used in many products such as intrusion alarms, fire alarms, thermal image analyzers for medical and environmental observation, and inexpensive and high-performance infrared sensors. Development is urgent.
【０００４】赤外線センサーは大きく分けて、量子型と
熱型の２種がある。前者は光電効果を利用したもので、
感度が良く、時定数が小さいが、波長依存性が大きく、
５μｍ以上の長波長では液体窒素温度以下に冷却しなけ
ればならないといった不便さがある。一方、後者の場合
は、物体から発する熱放射エネルギーを吸収して素子が
温度変化することを利用したもので、常温で動作するこ
と、波長依存性がないなどの利点がある。Infrared sensors are roughly classified into two types, a quantum type and a thermal type. The former uses the photoelectric effect,
Good sensitivity, small time constant, but large wavelength dependence,
With a long wavelength of 5 μm or more, there is the inconvenience of having to cool to below the liquid nitrogen temperature. On the other hand, in the latter case, the fact that the element changes in temperature by absorbing the heat radiation energy emitted from the object is utilized, and it has the advantages of operating at room temperature and having no wavelength dependence.
【０００５】熱型の赤外線センサーには、熱電対型、サ
ーミスタ型、ゴーレイ・セル型、さらに焦電型などがあ
る。この中でも焦電型の赤外線センサーは最も高感度で
あり主流を占めている。この焦電型の赤外線センサーは
赤外線を吸収することによって微弱な温度変化を発生さ
せ、これによって表面電荷が発生する効果を利用するも
のである。Thermal infrared sensors include thermocouple type, thermistor type, Golay cell type, and pyroelectric type. Of these, the pyroelectric infrared sensor has the highest sensitivity and occupies the mainstream. This pyroelectric infrared sensor utilizes an effect of generating a weak temperature change by absorbing infrared light and thereby generating a surface charge.
【０００６】上記のような焦電型の赤外線センサー等に
用いる焦電材料には、一般に次に示すような特性が要求
される。 （１）焦電係数γが高いこと （２）比誘電率εr が適度に小さいこと （３）体積比熱Ｃv が小さいこと （４）誘電損失 tanδが小さいことThe pyroelectric material used for the above pyroelectric infrared sensor or the like is generally required to have the following characteristics. (1) High pyroelectric coefficient γ (2) Reasonably small relative permittivity ε r (3) Small volume specific heat C v (4) Small dielectric loss tan δ
【０００７】実際に現在工業的に利用されている焦電材
料としては、ＬｉＴａＯ3 単結晶、Ｐｂ（Ｔｉ，Ｚｒ）
Ｏ3 やＰｂＴｉＯ3 系などのセラミックスが挙げられ
る。熱容量を小さくして赤外線吸収による温度変化を大
きくするため、素子は薄い方が好ましく、これらのバル
ク材料を薄板化して素子にしているのであるが、研磨加
工による薄板化は９０μｍが限界である。Pyroelectric materials that are actually industrially used at present include LiTaO 3 single crystal and Pb (Ti, Zr).
Ceramics such as O 3 and PbTiO 3 can be used. In order to reduce the heat capacity and increase the temperature change due to infrared absorption, it is preferable that the element is thin, and these bulk materials are thinned into the element, but the thinning by polishing is limited to 90 μm.
【０００８】赤外線センサーの性能向上と軽量化、及
び、高感度や高速応答を達成するために、焦電材料の薄
膜化の要求が急速に高まっている。これまで種々な強誘
電体材料の薄膜化が試みられている。これらの強誘電体
薄膜の組成はＰｂＴｉＯ3 系及びＰｂ（Ｔｉ，Ｚｒ）Ｏ
3 系についていえば、特開昭５９−１３８００４号、特
開昭６０−１３１７０３号および特開昭６０−１３１７
０４号公報にみられるようなＰｂサイトにＬａイオンを
置換した組成の（Ｐｂ，Ｌａ）ＴｉＯ3 および（Ｐｂ，
Ｌａ）（Ｚｒ，Ｔｉ）Ｏ3 、また特開平２−９４５０７
号にみられるようなＰｂサイトにＣａイオンを置換した
組成の（Ｐｂ，Ｃａ）（Ｚｒ，Ｔｉ）Ｏ3に限られる。[0008] In order to improve the performance of the infrared sensor, reduce its weight, and achieve high sensitivity and high-speed response, the demand for thinning the pyroelectric material is rapidly increasing. Until now, attempts have been made to reduce the thickness of various ferroelectric materials. The composition of these ferroelectric thin films is PbTiO 3 system and Pb (Ti, Zr) O.
As for the three systems, JP-A-59-138004, JP-A-60-131703, and JP-A-60-1317.
(Pb, La) TiO 3 and (Pb,
La) (Zr, Ti) O 3 , and JP-A-2-94507.
(Pb, Ca) (Zr, Ti) O 3 having a composition in which Ca ions are substituted for Pb sites as shown in No.
【０００９】また製法については、スパッタ法による成
膜の報告が多く、この場合は、これらの組成の酸化物粉
末もしくは焼結体、あるいは陽イオンの金属で構成され
たターゲットを用いて、基板加熱、または成膜後アニー
ルして製造するのが一般的である。Regarding the manufacturing method, there are many reports of film formation by the sputtering method. In this case, the substrate is heated by using an oxide powder or a sintered body of these compositions or a target composed of a cation metal. Or, it is generally manufactured by annealing after film formation.
【００１０】[0010]
【発明が解決しようとする課題】ところで、焦電薄膜の
組成に関する研究においては、膜成長と材料性能に直接
影響を及ぼすことから重要である。しかしながら、上述
のような種々の従来技術のＰｂＴｉＯ3 およびＰｂ（Ｔ
ｉ，Ｚｒ）Ｏ3 の薄膜形成技術においては、焦電係数、
誘電率、誘電損失の個々については、ある程度は改善さ
れたものの、未だ全てについては満足した特性を発揮す
る薄膜は得られていない。By the way, research on the composition of a pyroelectric thin film is important because it directly affects film growth and material performance. However, various prior art PbTiO 3 and Pb (T
In the thin film forming technique of i, Zr) O 3 , the pyroelectric coefficient,
Although each of the dielectric constant and the dielectric loss has been improved to some extent, a thin film that exhibits satisfactory properties has not yet been obtained for all of them.
【００１１】本発明は上記のような状況の下で、これま
でにない新しい組成のＰｂＴｉＯ3系及びＰｂ（Ｔｉ，
Ｚｒ）Ｏ3 系の強誘電体薄膜とその形成用ターゲット並
びにそれを用いた強誘電体薄膜の製造方法を提案するこ
とによって、優れたセンサー性能を発揮できる焦電材料
を提供することを目的とする。Under the above-mentioned circumstances, the present invention provides a new composition of PbTiO 3 and Pb (Ti,
It is an object of the present invention to provide a pyroelectric material that can exhibit excellent sensor performance by proposing a Zr) O 3 -based ferroelectric thin film, a target for forming the same, and a method for manufacturing a ferroelectric thin film using the same. To do.
【００１２】[0012]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明による強誘電体薄膜およびその形成用ター
ゲット並びにそれを用いた強誘電体薄膜の製造方法は、
以下の構成としたものである。In order to achieve the above object, a ferroelectric thin film, a target for forming the same, and a method of manufacturing a ferroelectric thin film using the same according to the present invention are
It has the following configuration.
【００１３】即ち、本発明による強誘電体薄膜は、Ｐｂ
ＴｉＯ3 のＰｂイオンサイトの一部をＮｄイオン、Ｓｍ
イオンまたはＧｄイオンのいずれかで置換して組成（Ｐ
ｂxＬｎy ）Ｔｉz Ｏ3 （但し、ＬｎはＮｄ、Ｓｍ、Ｇ
ｄのうちのいずれか１つであり、０．７０≦ｘ＜１、
０．９≦ｘ＋ｙ≦１、０．９５≦ｚ≦１、ｗ＝０）を有
するか、もしくはＰｂ（Ｔｉ，Ｚｒ）Ｏ3 のＰｂイオン
サイトの一部をＮｄイオン、ＳｍイオンまたはＧｄイオ
ンのいずれかで置換して組成（Ｐｂx Ｌｎy ）（Ｔｉz
Ｚｒw ）Ｏ3 （但し、ＬｎはＮｄ、Ｓｍ、Ｇｄのうちの
いずれか１つであり、０．７０≦ｘ＜１、０．９≦ｘ＋
ｙ≦１、０．５≦ｚ≦１、ｚ＋ｗ＝１）を有することを
特徴とする。また、これらは、室温において正方晶系の
結晶構造を有し、＜００１＞軸の方向に結晶成長させる
ことを特徴とする。That is, the ferroelectric thin film according to the present invention is Pb.
Part of the Pb ion site of TiO 3 is Nd ion, Sm
Composition by substituting with either ion or Gd ion (P
b x Ln y) Ti z O 3 ( where, Ln is Nd, Sm, G
any one of d, 0.70 ≦ x <1,
0.9 ≦ x + y ≦ 1, 0.95 ≦ z ≦ 1, w = 0), or a part of the Pb ion site of Pb (Ti, Zr) O 3 is replaced with Nd ion, Sm ion or Gd ion. The composition was replaced with any (Pb x Ln y) (Ti z
Zr w ) O 3 (where Ln is any one of Nd, Sm and Gd, and 0.70 ≦ x <1 and 0.9 ≦ x +
y ≦ 1, 0.5 ≦ z ≦ 1, z + w = 1). Further, these have a tetragonal crystal structure at room temperature, and are characterized by crystal growth in the <001> axis direction.
【００１４】また本発明による強誘電体薄膜形成用ター
ゲットは、上記の化学組成、もしくはこれに３０モル％
以下のＰｂＯを含む化学組成を有することを特徴とし、
さらに本発明による強誘電体薄膜の製造方法は、上記の
ターゲットを粉末もしくは焼結体とし、そのターゲット
を用いて、スパッタリング法によりペロブスカイト構造
を有する強誘電体薄膜を基板上に堆積することを特徴と
する。Further, the target for forming a ferroelectric thin film according to the present invention has the above chemical composition or 30 mol% thereof.
Characterized by having the following chemical composition containing PbO:
Furthermore, the method for producing a ferroelectric thin film according to the present invention is characterized in that the above target is a powder or a sintered body, and the target is used to deposit a ferroelectric thin film having a perovskite structure on a substrate by a sputtering method. And
【００１５】[0015]
【作用】上記のように本発明による強誘電体薄膜は、Ｐ
ｂＴｉＯ3 またはＰｂ（Ｔｉ，Ｚｒ）Ｏ3 のＰｂイオン
サイトの一部をＮｄイオン、ＳｍイオンまたはＧｄイオ
ンのいずれかで置換することにより、キュリー温度が下
がり、室温における焦電係数は増加し、かつ＜００１＞
軸の方向に結晶成長させることにより比誘電率が減少
し、よって性能評価指数が大きくなり、焦電センサー素
子として極めて優れた特性を発揮できる。As described above, the ferroelectric thin film according to the present invention has P
By substituting part of the Pb ion site of bTiO 3 or Pb (Ti, Zr) O 3 with either Nd ion, Sm ion or Gd ion, the Curie temperature is lowered and the pyroelectric coefficient at room temperature is increased, And <001>
By growing the crystal in the axial direction, the relative permittivity is reduced, the performance evaluation index is increased, and extremely excellent characteristics as a pyroelectric sensor element can be exhibited.
【００１６】また本発明による強誘電体薄膜形成用ター
ゲットは、ＰｂＴｉＯ3 またはＰｂ（Ｔｉ，Ｚｒ）Ｏ3
のＰｂイオンサイトの一部をＮｄイオン、Ｓｍイオンま
たはＧｄイオンのいずれかで置換した組成、もしくはこ
れに３０モル％以下のＰｂＯを含む組成としたことで、
所定の化学量論組成の強誘電体薄膜の形成が可能とな
る。The target for forming a ferroelectric thin film according to the present invention is PbTiO 3 or Pb (Ti, Zr) O 3.
By substituting a part of the Pb ion site of Nd ion, Sm ion, or Gd ion, or a composition containing 30 mol% or less of PbO,
It is possible to form a ferroelectric thin film having a predetermined stoichiometric composition.
【００１７】さらに本発明による強誘電体薄膜の製造方
法によれば、上記のターゲットを粉末または焼結体と
し、そのターゲットを用いてスパッタリング法によりペ
ロブスカイト構造を有する強誘電体薄膜を基板上に堆積
させることで、前記のように極めて優れた特性を有する
強誘電体薄膜を容易に製造することが可能となる。Further, according to the method of manufacturing a ferroelectric thin film of the present invention, the target is powder or a sintered body, and the target is used to deposit a ferroelectric thin film having a perovskite structure on a substrate by a sputtering method. By doing so, it becomes possible to easily manufacture a ferroelectric thin film having extremely excellent characteristics as described above.
【００１８】なお上記のように３０モル％以下のＰｂＯ
を含ませるのは、成膜条件によっては、例えば基板を加
熱しながら成膜するような条件では、膜からＰｂＯが揮
発して欠損しやすくなり、これを防ぐために成膜中に過
剰のＰｂ成分が供給できるように配慮したものである。
なお、ターゲット中の過剰のＰｂＯ量が３０モル％を越
えると、Ｐｂ成分の供給量が多すぎて良質の膜が得られ
ない。As described above, PbO of 30 mol% or less is used.
Depending on the film forming conditions, for example, under the condition that the film is formed while heating the substrate, PbO volatilizes easily from the film and is likely to be lost. To prevent this, excessive Pb component during film formation is included. Are designed to be supplied.
If the amount of excess PbO in the target exceeds 30 mol%, the amount of Pb component supplied is too large to obtain a good quality film.
【００１９】[0019]
【実施例】以下、本発明による強誘電体薄膜及びその形
成用ターゲット並びにそれを用いた強誘電体薄膜の製造
方法を、実施例に基づいて具体的に説明する。EXAMPLES The ferroelectric thin film, the target for forming the same, and the method for manufacturing a ferroelectric thin film using the same according to the present invention will be specifically described below based on examples.
【００２０】〔実施例１〜１２〕先ず、｛１００｝面に
沿ってへき開研磨した酸化マグネシウム単結晶基板上に
下部電極として０．２μｍの白金膜をエピタキシャル形
成させた。この下部電極を形成させた基板上に、（Ｐ
ｂ，Ｌｎ）ＴｉＯ3 または（Ｐｂ，Ｌｎ）（Ｔｉ，Ｚ
ｒ）Ｏ3 の組成を有し、ＬｎとしてＮｄ、ＳｍまたはＧ
ｄのいずれか１つをそれぞれ異なる割合で含む数種の強
誘電体薄膜を以下に述べる手順で高周波マグネトロンス
パッタリング法で作製した。Examples 1 to 12 First, a 0.2 μm platinum film was epitaxially formed as a lower electrode on a magnesium oxide single crystal substrate cleaved and polished along the {100} plane. On the substrate on which this lower electrode is formed, (P
b, Ln) TiO 3 or (Pb, Ln) (Ti, Z
r) has a composition of O 3 and has Nd, Sm, or G as Ln.
Several kinds of ferroelectric thin films containing any one of d in different ratios were produced by the high frequency magnetron sputtering method by the procedure described below.
【００２１】ターゲット原料には、目的としている膜組
成と同じ組成の原料を軽く焼結させた粉末とＰｂＯ粉末
をモル比で９０：１０または８５：１５または８０：２
０の割合で配合して混合した粉末を用い、この混合粉末
を無酸素銅製のターゲット皿に敷き詰め表面を平にしな
がら押し固めてターゲットとした。そのターゲットの組
成を下記表１に示す。As the target raw material, a powder obtained by lightly sintering a raw material having the same composition as the target film composition and PbO powder are used in a molar ratio of 90:10 or 85:15 or 80: 2.
A powder mixed and mixed at a ratio of 0 was used, and this mixed powder was spread on a target dish made of oxygen-free copper and pressed while flattening the surface to obtain a target. The composition of the target is shown in Table 1 below.
【００２２】 [0022]
【００２３】図１は本実施例で用いたプレーナーマグネ
トロンスパッタ装置の概略構成を示すもので、図におい
て１はアノード、２はカソードであり、そのカソード上
のターゲット設置面２ａ上にターゲット３を設置し、そ
の上方の基板ホルダ４に前記の下部電極を形成した酸化
マグネシウム単結晶基板５を固定してスパッタリングを
行った。そのときの雰囲気ガスはＡｒ９０％とＯ2 １０
％の混合気体で、全圧は１Ｐａとした。またターゲット
３と基板５との距離は１０ｃｍに設定し、基板５をヒー
タ６により６００℃まで加熱してから厚みが約２．５μ
ｍの薄膜を作製した。なお図１中、７ａ・７ｂはガス流
入口および排出口、８は永久磁石、９は冷却水出入口を
示す。FIG. 1 shows a schematic structure of a planar magnetron sputtering apparatus used in this embodiment. In the figure, 1 is an anode, 2 is a cathode, and a target 3 is installed on a target installation surface 2a on the cathode. Then, the magnesium oxide single crystal substrate 5 having the lower electrode formed thereon was fixed to the substrate holder 4 above it, and sputtering was performed. At that time, the atmosphere gas was Ar 90% and O 2 10
%, And the total pressure was 1 Pa. The distance between the target 3 and the substrate 5 is set to 10 cm, and the thickness of the substrate 5 is about 2.5 μm after the substrate 5 is heated to 600 ° C. by the heater 6.
A thin film of m was prepared. In FIG. 1, 7a and 7b are gas inlets and outlets, 8 is a permanent magnet, and 9 is a cooling water inlet / outlet.
【００２４】上記のようにして作製した薄膜の組成を、
Ｘ線マイクロアナライザーで測定した結果、ターゲット
と同じ組成であることがわかった。また作製した薄膜の
Ｘ線回析測定から、得られた膜は強く（００１）配向し
ており、００１回析ピークの強度Ｉ001 と１００回析ピ
ークの強度Ｉ100 から次式を用いて（００１）配向率を
算出した。 （００１）配向率＝Ｉ001 ／（Ｉ001 ＋Ｉ100 ） さらに、電子線回析より回析図形がスポットになってい
ることからエピタキシャル成長していることがわかっ
た。The composition of the thin film produced as described above is
As a result of measurement with an X-ray microanalyzer, it was found that the composition was the same as that of the target. The X-ray diffraction measurement of the prepared thin film revealed that the obtained film had a strong (001) orientation, and the intensity of the 001 diffraction peak was I 001 and the intensity of the 100 diffraction peak was I 100 , using the following equation ( 001) The orientation rate was calculated. (001) Orientation ratio = I 001 / (I 001 + I 100 ) Furthermore, it was found from electron beam diffraction that the diffraction pattern was a spot, indicating that epitaxial growth was performed.
【００２５】次に、電気特性を測定するために、上記の
ように（００１）配向した膜の表面に約０．２μｍの白
金膜を上部電極として形成させた。そして分極処理をし
ないで得られた膜の焦電特性を測定した結果、焦電流が
観測された。このことから、アズグローン（as-grown）
膜の状態で自発分極の向きが揃っており、バルク結晶の
ように分極処理するこなく、そのまま赤外線センサーと
して利用できることがわかった。さらに焦電係数γと比
誘電率εr 及び誘電損失 tanδを測定し、これらの測定
値から膜の性能評価指数γ／ｃv （εr tanδ）1/2 を
算出した。以上の結果を下記表２にまとめて示す。Next, in order to measure the electrical characteristics, a platinum film of about 0.2 μm was formed as an upper electrode on the surface of the (001) oriented film as described above. Then, as a result of measuring the pyroelectric property of the film obtained without polarization treatment, a pyroelectric current was observed. From this, as-grown
It was found that the direction of spontaneous polarization is uniform in the state of the film, and it can be used as it is as an infrared sensor without being subjected to polarization treatment as in bulk crystals. Further, the pyroelectric coefficient γ, the relative dielectric constant ε r and the dielectric loss tan δ were measured, and the performance evaluation index γ / cv (ε r tan δ) 1/2 of the film was calculated from these measured values. The above results are summarized in Table 2 below.
【００２６】 なお上記表中の単位は、キュリー温度〔℃〕、焦電係数
〔×10-8C/cm2K〕、性能評価指数〔×10-9Ccm/J 〕であ
る。[0026] The units in the above table are Curie temperature [° C.], pyroelectric coefficient [× 10 −8 C / cm 2 K], and performance evaluation index [× 10 −9 Ccm / J].
【００２７】〔比較例１〜３〕上記実施例に対する比較
例として従来の強誘電体薄膜の組成と特性を下記表３に
示す。Comparative Examples 1 to 3 Table 3 below shows the composition and characteristics of a conventional ferroelectric thin film as a comparative example to the above examples.
【００２８】 [0028]
【００２９】上記の表３と本発明による前記の表２との
対比から明らかなように、本発明の組成を有する薄膜
は、従来の組成の薄膜と比較して特性が格段に向上した
極めて優れた焦電材料であることがわかる。As is clear from the comparison between Table 3 above and Table 2 according to the present invention, the thin film having the composition of the present invention is extremely excellent in the characteristics as compared with the thin film of the conventional composition. It can be seen that it is a pyroelectric material.
【００３０】[0030]
【発明の効果】以上説明したように本発明は、本発明の
強誘電体薄膜は、バルク結晶のように分極処理すること
なく、またセラミックスなどのように切断研磨加工も必
要とせず、得られた薄膜が、従来に比較して大きな性能
評価指数を有するなど焦電材料としての電気特性に格段
に優れるものである。また、本発明による強誘電体薄膜
形成用ターゲットおよび強誘電体薄膜の製造方法によれ
ば、高感度、高速応答を可能とする焦電センサー材料と
して工業的に極めて価値の高い強誘電体薄膜を容易に製
造することができる等の効果がある。As described above, the present invention can be obtained without the ferroelectric thin film of the present invention being polarized like the bulk crystal and the cutting and polishing process like the ceramics. The thin film has a large performance evaluation index as compared with the conventional thin film and is remarkably excellent in electrical characteristics as a pyroelectric material. Further, according to the target for forming a ferroelectric thin film and the method for manufacturing a ferroelectric thin film according to the present invention, a ferroelectric thin film industrially extremely valuable as a pyroelectric sensor material capable of high sensitivity and high speed response is obtained. It has an effect that it can be easily manufactured.
【図１】本発明の実施例で用いたスパッタ装置の概略構
成を示す縦断面図。FIG. 1 is a vertical sectional view showing a schematic configuration of a sputtering apparatus used in an example of the present invention.
１ アノード ２ カソード ３ ターゲット ４ 基板ホルダ ５ 基板 1 Anode 2 Cathode 3 Target 4 Substrate holder 5 Substrate
Claims (3)
り、＜００１＞軸の方向に結晶成長させた下記化学式
（Ｉ）で表される組成を有することを特徴とする強誘電
体薄膜。 （Ｐｂx Ｌｎy ）（Ｔｉz Ｚｒw ）Ｏ3 ・・・・・（Ｉ） 但し、 ＬｎはＮｄ、Ｓｍ、Ｇｄのうちの１つ ｘ、ｙ、ｚ、ｗは、 ０．７０≦ｘ＜１、０．９≦ｘ＋ｙ≦１、０．９５≦ｚ
≦１、ｗ＝０ または、 ０．７０≦ｘ＜１、０．９≦ｘ＋ｙ≦１、０．５≦ｚ≦
１、ｚ＋ｗ＝１1. A ferroelectric thin film having a tetragonal crystal structure at room temperature and having a composition represented by the following chemical formula (I) grown in the <001> axis direction. (Pb x Ln y) (Ti z Zr w) O 3 ····· (I) where, Ln is Nd, Sm, 1 single x, y, z, w of Gd is, 0.70 ≦ x <1, 0.9 ≦ x + y ≦ 1, 0.95 ≦ z
≦ 1, w = 0 or 0.70 ≦ x <1, 0.9 ≦ x + y ≦ 1, 0.5 ≦ z ≦
1, z + w = 1
ることを特徴とする強誘電体薄膜形成用ターゲット。 （１−α）（Ｐｂx Ｌｎy ）（Ｔｉz Ｚｒw ）Ｏ3 ＋α・ＰｂＯ・・（II） 但し、 ＬｎはＮｄ、Ｓｍ、Ｇｄのうちの１つ ｘ、ｙ、ｚ、ｗ、αは、 ０．７０≦ｘ＜１、０．９≦ｘ＋ｙ≦１、０．９５≦ｚ
≦１、ｗ＝０、０≦α≦０．３ または、 ０．７０≦ｘ＜１、０．９≦ｘ＋ｙ≦１、０．５≦ｚ≦
１、ｚ＋ｗ＝１、０≦α≦０．３2. A target for forming a ferroelectric thin film, which has a composition represented by the following chemical formula (II). (1-α) (Pb x Ln y) (Ti z Zr w) O 3 + α · PbO ·· (II) where, Ln is Nd, Sm, one of Gd x, y, z, w , α Is 0.70 ≦ x <1, 0.9 ≦ x + y ≦ 1, 0.95 ≦ z
≦ 1, w = 0, 0 ≦ α ≦ 0.3 or 0.70 ≦ x <1, 0.9 ≦ x + y ≦ 1, 0.5 ≦ z ≦
1, z + w = 1, 0 ≦ α ≦ 0.3
ーゲットを粉末もしくは焼結体とし、そのターゲットと
して用いてスパッタリング法によりペロブスカイト構造
を有する強誘電体薄膜を基板上に堆積することを特徴と
する強誘電体薄膜の製造方法。3. A ferroelectric thin film forming target according to claim 2, which is a powder or a sintered body, is used as a target to deposit a ferroelectric thin film having a perovskite structure on a substrate by a sputtering method. A method for manufacturing a ferroelectric thin film, which is characterized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7079533A JPH08253323A (en) | 1995-03-10 | 1995-03-10 | Ferroelectric thin film, target for forming the same and production of ferroelectric thin film usint the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7079533A JPH08253323A (en) | 1995-03-10 | 1995-03-10 | Ferroelectric thin film, target for forming the same and production of ferroelectric thin film usint the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08253323A true JPH08253323A (en) | 1996-10-01 |
Family
ID=13692638
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7079533A Withdrawn JPH08253323A (en) | 1995-03-10 | 1995-03-10 | Ferroelectric thin film, target for forming the same and production of ferroelectric thin film usint the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08253323A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6121647A (en) * | 1996-06-26 | 2000-09-19 | Tdk Corporation | Film structure, electronic device, recording medium, and process of preparing ferroelectric thin films |
-
1995
- 1995-03-10 JP JP7079533A patent/JPH08253323A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6121647A (en) * | 1996-06-26 | 2000-09-19 | Tdk Corporation | Film structure, electronic device, recording medium, and process of preparing ferroelectric thin films |
| US6387712B1 (en) | 1996-06-26 | 2002-05-14 | Tdk Corporation | Process for preparing ferroelectric thin films |
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