JPH05226322A - Manufacture of oriented ferroelectric thin film - Google Patents
Manufacture of oriented ferroelectric thin filmInfo
- Publication number
- JPH05226322A JPH05226322A JP2420592A JP2420592A JPH05226322A JP H05226322 A JPH05226322 A JP H05226322A JP 2420592 A JP2420592 A JP 2420592A JP 2420592 A JP2420592 A JP 2420592A JP H05226322 A JPH05226322 A JP H05226322A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- ferroelectric thin
- ferroelectric
- ferroelectric substance
- electric field
- 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
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Landscapes
- Local Oxidation Of Silicon (AREA)
- Semiconductor Memories (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、不揮発メモリ素子、キ
ャパシタ、光変調素子、圧電素子、焦電型赤外線センサ
などに用いられる配向性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 an oriented ferroelectric thin film used for a nonvolatile memory element, a capacitor, a light modulation element, a piezoelectric element, a pyroelectric infrared sensor and the like.
【０００２】[0002]
【従来の技術】近年の半導体技術の進歩により、様々な
電子部品は小型化、集積化が大いに進んでいる。これに
伴い、不揮発メモリ素子、キャパシタ、光変調素子、圧
電素子、焦電型赤外線センサなどに応用されている強誘
電体素子も、小型化、薄膜化が期待されている。2. Description of the Related Art Due to recent advances in semiconductor technology, various electronic components have been greatly miniaturized and integrated. Along with this, it is expected that the ferroelectric elements applied to non-volatile memory elements, capacitors, optical modulators, piezoelectric elements, pyroelectric infrared sensors, etc. will be made smaller and thinner.
【０００３】上記不揮発メモリ素子、圧電素子、焦電型
赤外線センサなどの強誘電体素子では、強誘電体の自発
分極Ｐsの変化を出力として利用しており、Ｐsが一方向
に揃って配向しているときＰsの変化が最大となるた
め、このとき最も大きい出力が得られる。In the ferroelectric element such as the nonvolatile memory element, the piezoelectric element, and the pyroelectric infrared sensor, the change in the spontaneous polarization Ps of the ferroelectric substance is used as an output, and Ps is aligned in one direction. Since the change in Ps is maximum during the above, the largest output is obtained at this time.
【０００４】例えば、最も実用化されているＰＺＴ、Ｐ
ｂＴｉＯ3（チタン酸鉛）、ＢａＴｉＯ3（チタン酸バリ
ウム）等の酸化物強誘電体の結晶構造は、室温で正方晶
のペロブスカイト構造であり、自発分極Ｐsは（００
１）方向に向いている。したがって、これらの酸化物強
誘電体薄膜では、半導体などの基板に垂直に（００１）
方向を配向させる技術が重要となっている。また、強誘
電体薄膜中に何らかの欠陥があると、電界印加時にリー
クを生じたり、電極から電子の注入が起こり耐久性の劣
化を引き起こすので、欠陥のない膜質の良好な強誘電体
薄膜を半導体などの基板に形成することが重要な技術と
なっている。For example, the most practically used PZT, P
The crystal structure of oxide ferroelectrics such as bTiO 3 (lead titanate) and BaTiO 3 (barium titanate) is a tetragonal perovskite structure at room temperature, and the spontaneous polarization Ps is (00
1) Face the direction. Therefore, in these oxide ferroelectric thin films, (001) is perpendicular to a substrate such as a semiconductor.
Techniques for orienting directions are important. Also, if there is any defect in the ferroelectric thin film, leakage will occur when an electric field is applied, or electrons will be injected from the electrodes, which will deteriorate the durability. It is an important technology to form it on a substrate such as.
【０００５】従来、これらの強誘電体薄膜の形成法の一
例として、反応性高周波スパッタリング法が知られてい
る。この形成法では、アルゴン、酸素等のガスをスパッ
タチャンバ内に導入してグロー放電を発生させ、アルゴ
ンイオンによってターゲットからスパッタされたＰＺＴ
等を、高温に保たれた基板上で酸素と反応させることに
よって酸化物強誘電体薄膜を形成している。Conventionally, a reactive high frequency sputtering method has been known as an example of a method for forming these ferroelectric thin films. In this forming method, a gas such as argon or oxygen is introduced into the sputtering chamber to generate a glow discharge, and PZT sputtered from the target by argon ions.
And the like are reacted with oxygen on a substrate kept at a high temperature to form an oxide ferroelectric thin film.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上記の
従来の方法では、基板に対して垂直に十分に配向した強
誘電体薄膜が得られていなかった。また、良好な強誘電
特性を発現させるために、成膜後に酸素雰囲気中で熱処
理を施す方法が提案されているが、この方法は、処理温
度、処理時間、酸素ガス圧力、使用する基板の種類等微
妙な条件が必要とされ、また、この後熱処理を施した後
でも、配向性や膜質の点で、十分な強誘電体薄膜はいま
だ得られておらず、バルクに比べて強誘電特性、耐久性
は非常に劣っているのが現状である。However, in the above-mentioned conventional method, a ferroelectric thin film which is sufficiently oriented perpendicular to the substrate has not been obtained. In addition, a method has been proposed in which heat treatment is performed in an oxygen atmosphere after film formation in order to exhibit good ferroelectric properties. This method involves treatment temperature, treatment time, oxygen gas pressure, and type of substrate used. Delicate conditions are required, and even after this heat treatment, sufficient ferroelectric thin film has not yet been obtained in terms of orientation and film quality. At present, the durability is very poor.
【０００７】本発明は、上記事情に鑑み、良質な膜質
で、基板に対して十分に配向した、良好な強誘電性を有
する配向性強誘電体薄膜の製造方法を提供することを目
的とする。In view of the above circumstances, it is an object of the present invention to provide a method for producing an oriented ferroelectric thin film which has a good film quality, is sufficiently oriented with respect to a substrate, and has good ferroelectricity. ..
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するた
め、強誘電体薄膜を形成した後、前記強誘電体薄膜に電
界を印加した状態で熱処理を施すことにより、配向性強
誘電体薄膜を製造する。In order to solve the above problems, after forming a ferroelectric thin film, a heat treatment is applied to the ferroelectric thin film in a state of applying an electric field to form an oriented ferroelectric thin film. To manufacture.
【０００９】[0009]
【作用】本発明によれば、強誘電体薄膜の後熱処理中に
印加する電界の効果により、強誘電体薄膜の各構成原子
が安定な格子位置に移動するため、膜質も良質であり、
かつ基板に対して十分に配向した良好な強誘電性を有す
る配向性強誘電体薄膜を製造することが可能になる。According to the present invention, each constituent atom of the ferroelectric thin film moves to a stable lattice position by the effect of the electric field applied during the post-heat treatment of the ferroelectric thin film, so that the film quality is good.
In addition, it becomes possible to manufacture an oriented ferroelectric thin film which is well oriented with respect to the substrate and has good ferroelectricity.
【００１０】[0010]
【実施例】以下、本発明の一実施例を図面を参照して説
明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
【００１１】図１は本発明の配向性強誘電体薄膜の製造
方法に用いられる熱処理装置の一例を示している。図１
において、１は酸素雰囲気を保ち熱処理を行うためのチ
ャンバ、２は赤外線をチャンバ１内に導入するための石
英製窓、３は加熱用赤外線ランプ、４は赤外線を効率良
く集光させるための赤外線ミラー、５は強誘電体薄膜に
電界を印加できる構造に形成した強誘電体薄膜素子、６
は強誘電体薄膜素子５を赤外線の集光位置に保持するた
めの石英製基板ホルダ、７はチャンバ１内を真空排気す
るための排気口、８はチャンバ１内に酸素ガスを導入す
るためのガス導入口である。FIG. 1 shows an example of a heat treatment apparatus used in the method for producing an oriented ferroelectric thin film of the present invention. Figure 1
In the figure, 1 is a chamber for carrying out a heat treatment while keeping an oxygen atmosphere, 2 is a quartz window for introducing infrared rays into the chamber 1, 3 is an infrared lamp for heating, and 4 is infrared rays for efficiently collecting infrared rays. Mirrors 5 are ferroelectric thin film elements formed in a structure capable of applying an electric field to the ferroelectric thin film, 6
Is a quartz substrate holder for holding the ferroelectric thin film element 5 at a position where infrared rays are focused, 7 is an exhaust port for evacuating the chamber 1, and 8 is for introducing oxygen gas into the chamber 1. It is a gas inlet.
【００１２】図２は強誘電体薄膜を形成した強誘電体薄
膜素子５の膜構造を示した概略図である。図２におい
て、９は（１００）面でへき開したＭｇＯ（酸化マグネ
シウム）基板、１０は第１のＰｔ（白金）電極、１１は
強誘電体薄膜であるＰＺＴ薄膜、１２は第２のＰｔ（白
金）電極である。FIG. 2 is a schematic view showing the film structure of a ferroelectric thin film element 5 having a ferroelectric thin film formed thereon. In FIG. 2, 9 is a MgO (magnesium oxide) substrate cleaved at the (100) plane, 10 is a first Pt (platinum) electrode, 11 is a PZT thin film that is a ferroelectric thin film, and 12 is a second Pt (platinum). ) An electrode.
【００１３】図２の強誘電体薄膜素子５は、（１００）
面でへき開したＭｇＯ基板９上に、第１のＰｔ電極１０
が１００ｎｍの膜厚で、その上に強誘電体薄膜であるＰ
ＺＴ薄膜１１が５００ｎｍの膜厚で、さらにその上に第
２のＰｔ電極１２が１００ｎｍの膜厚で、それぞれ順次
にスパッタ法により成膜され、作製されている。ここ
で、第１のＰｔ電極１０と第２のＰｔ電極１２との間に
は、電界を印加できるようになっている。The ferroelectric thin film element 5 shown in FIG.
On the MgO substrate 9 cleaved at the surface, the first Pt electrode 10
Has a film thickness of 100 nm, and a ferroelectric thin film P
The ZT thin film 11 having a film thickness of 500 nm and the second Pt electrode 12 having a film thickness of 100 nm thereon are sequentially formed by the sputtering method to be manufactured. Here, an electric field can be applied between the first Pt electrode 10 and the second Pt electrode 12.
【００１４】なお、第１のＰｔ電極１０、ＰＺＴ薄膜１
１、第２のＰｔ電極１２の成膜方法は、真空蒸着法、化
学気相成長法（ＣＶＤ法）などを用いても良い。The first Pt electrode 10 and the PZT thin film 1
As the film forming method of the first and second Pt electrodes 12, a vacuum vapor deposition method, a chemical vapor deposition method (CVD method) or the like may be used.
【００１５】本発明の配向性強誘電体薄膜の製造方法
は、上記図２に示す強誘電体薄膜素子５等の作製の際
に、次のように用いられる。すなわち、図１の熱処理装
置において、まずチャンバ１内の石英製基板ホルダ６に
強誘電体薄膜が成膜された強誘電体薄膜素子５を取り付
け、チャンバ１内を排気口７から真空ポンプ（図示せ
ず）により真空排気し、その後ガス導入口８から酸素ガ
スを導入する。このとき、導入酸素ガス量と排気速度と
の関係によって、ガス圧力を調整できるようにし、熱処
理中の一定のガス圧力を保つ。The method of manufacturing the oriented ferroelectric thin film of the present invention is used as follows when manufacturing the ferroelectric thin film element 5 shown in FIG. That is, in the heat treatment apparatus of FIG. 1, first, the ferroelectric thin film element 5 on which the ferroelectric thin film is formed is attached to the quartz substrate holder 6 in the chamber 1, and the inside of the chamber 1 is vacuum pumped from the exhaust port 7 (see FIG. Vacuum exhaust is performed by (not shown), and then oxygen gas is introduced from the gas inlet 8. At this time, the gas pressure can be adjusted according to the relationship between the amount of introduced oxygen gas and the exhaust speed, and a constant gas pressure is maintained during the heat treatment.
【００１６】そして上記の状態で、強誘電体薄膜素子５
の第１のＰｔ電極１０と第２のＰｔ電極１２との間に２
〜５Ｖの電界を印加する。このとき、加熱用赤外線ラン
プ３からの赤外線を石英製窓２を介して、赤外線反射ミ
ラー４によりチャンバ１内の強誘電体薄膜素子５に集光
させ、強誘電体薄膜素子５の温度を６００〜７００℃に
保持する。このように、成膜後の熱処理の際に電界を印
加することにより、強誘電体薄膜の配向性を向上させ
る。In the above state, the ferroelectric thin film element 5
Between the first Pt electrode 10 and the second Pt electrode 12 of
An electric field of ~ 5V is applied. At this time, the infrared rays from the heating infrared lamp 3 are focused on the ferroelectric thin film element 5 in the chamber 1 by the infrared reflection mirror 4 through the quartz window 2, and the temperature of the ferroelectric thin film element 5 is set to 600. Hold at ~ 700 ° C. Thus, the orientation of the ferroelectric thin film is improved by applying the electric field during the heat treatment after the film formation.
【００１７】なお、強誘電体薄膜素子５を加熱するため
の方法としては、この実施例では赤外線ランプを用いて
いるが、これだけではなく、抵抗加熱ヒータによるもの
など、強誘電体薄膜素子５を上記の温度に加熱できる方
法であれば良い。In this embodiment, an infrared lamp is used as a method for heating the ferroelectric thin film element 5, but the method is not limited to this. Any method capable of heating to the above temperature may be used.
【００１８】このようにして作製した強誘電体薄膜素子
５は、ＰＺＴ薄膜１１において容易に分極し、膜質も酸
素欠損などがなく良好なものとなり、自発分極Ｐsも大
きくなり、分極反転の耐久性も向上した。The ferroelectric thin film element 5 thus manufactured is easily polarized in the PZT thin film 11, the film quality is good with no oxygen deficiency, the spontaneous polarization Ps is large, and the durability of polarization reversal is high. Also improved.
【００１９】[0019]
【発明の効果】以上のように、本発明の配向性強誘電体
薄膜の製造方法によれば、強誘電体薄膜に電界を印加し
た状態で熱処理を施すことにより、良質な膜質で、かつ
基板に対して十分に配向した、良好な強誘電特性を有す
る強誘電体薄膜を得ることができ、ゆえに、高性能な強
誘電体素子を提供することが可能となる。As described above, according to the method for producing an oriented ferroelectric thin film of the present invention, the ferroelectric thin film is heat-treated in the state where an electric field is applied. It is possible to obtain a ferroelectric thin film that is sufficiently oriented with respect to the above and has good ferroelectric characteristics, and thus it is possible to provide a high-performance ferroelectric element.
【図１】本発明の配向性強誘電体薄膜の製造方法に用い
られる熱処理装置の一例の模式図である。FIG. 1 is a schematic view of an example of a heat treatment apparatus used in a method for producing an oriented ferroelectric thin film of the present invention.
【図２】本発明の製造方法により製造される配向性強誘
電体薄膜を有する強誘電体薄膜素子の膜構造を示した概
略図である。FIG. 2 is a schematic view showing a film structure of a ferroelectric thin film element having an oriented ferroelectric thin film manufactured by the manufacturing method of the present invention.
１ チャンバ ２ 赤外線導入用石英製窓 ３ 加熱用赤外線ランプ ４ 赤外線反射ミラー ５ 強誘電体薄膜素子 ６ 基板ホルダ ７ 排気口 ８ ガス導入口 ９ ＭｇＯ（酸化マグネシウム）基板 １０ 第１のＰｔ（白金）電極 １１ ＰＺＬ薄膜 １２ 第２のＰｔ（白金）電極 DESCRIPTION OF SYMBOLS 1 Chamber 2 Infrared introduction quartz window 3 Heating infrared lamp 4 Infrared reflection mirror 5 Ferroelectric thin film element 6 Substrate holder 7 Exhaust port 8 Gas introduction port 9 MgO (magnesium oxide) substrate 10 First Pt (platinum) electrode 11 PZL thin film 12 Second Pt (platinum) electrode
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｌ 41/24 9274−4Ｍ Ｈ０１Ｌ 41/22 Ｚ (72)発明者 大谷 昇 大阪府大阪市阿倍野区長池町22番22号 シ ャープ株式会社内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification number Internal reference number FI Technical indication location H01L 41/24 9274-4M H01L 41/22 Z (72) Inventor Noboru Otani Mayor Abeno Ward, Osaka City, Osaka Prefecture 22-22 Ikemachi Sharp Co., Ltd.
Claims (1)
体薄膜に電界を印加した状態で熱処理を施すことを特徴
とする配向性強誘電体薄膜の製造方法。1. A method for producing an oriented ferroelectric thin film, which comprises forming a ferroelectric thin film and then subjecting the ferroelectric thin film to a heat treatment while an electric field is applied.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2420592A JPH05226322A (en) | 1992-02-12 | 1992-02-12 | Manufacture of oriented ferroelectric thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2420592A JPH05226322A (en) | 1992-02-12 | 1992-02-12 | Manufacture of oriented ferroelectric thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05226322A true JPH05226322A (en) | 1993-09-03 |
Family
ID=12131816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2420592A Pending JPH05226322A (en) | 1992-02-12 | 1992-02-12 | Manufacture of oriented ferroelectric thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05226322A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5645760A (en) * | 1994-06-14 | 1997-07-08 | Sharp Kabushiki Kaisha | Polymeric compounds, and liquid crystal element using the same |
| JP2010199265A (en) * | 2009-02-25 | 2010-09-09 | Seiko Epson Corp | Method for manufacturing liquid ejecting head and method for manufacturing actuator device |
-
1992
- 1992-02-12 JP JP2420592A patent/JPH05226322A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5645760A (en) * | 1994-06-14 | 1997-07-08 | Sharp Kabushiki Kaisha | Polymeric compounds, and liquid crystal element using the same |
| US5702642A (en) * | 1994-06-14 | 1997-12-30 | Sharp Kabushiki Kaisha | Polymeric compounds, and liquid crystal element using the same |
| JP2010199265A (en) * | 2009-02-25 | 2010-09-09 | Seiko Epson Corp | Method for manufacturing liquid ejecting head and method for manufacturing actuator device |
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