JPH0587164B2 - - Google Patents
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- Publication number
- JPH0587164B2 JPH0587164B2 JP21677588A JP21677588A JPH0587164B2 JP H0587164 B2 JPH0587164 B2 JP H0587164B2 JP 21677588 A JP21677588 A JP 21677588A JP 21677588 A JP21677588 A JP 21677588A JP H0587164 B2 JPH0587164 B2 JP H0587164B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- dielectric
- lower electrode
- tio
- batio
- 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
- 239000010408 film Substances 0.000 claims description 64
- 239000003990 capacitor Substances 0.000 claims description 17
- 239000010409 thin film Substances 0.000 claims description 16
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 9
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 229910052763 palladium Inorganic materials 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 2
- 229910000510 noble metal Inorganic materials 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 6
- 238000009413 insulation Methods 0.000 description 6
- 239000012212 insulator Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 229910052594 sapphire Inorganic materials 0.000 description 3
- 239000010980 sapphire Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は誘電体膜中のピンホールによる電気的
短絡が無く、絶縁耐圧及びその分布に優れた高誘
電率薄膜キヤパシタの作製方法に関するものであ
る。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a high dielectric constant thin film capacitor which is free from electrical short circuits due to pinholes in the dielectric film and has excellent dielectric strength and its distribution. be.
（従来の技術）
電子部品及び集積回路における素子の小型・集
積化にともない、薄膜キヤパシタの需要は益々大
きくなつている。これらの薄膜キヤパシタでは小
面積かつ大容量の要求があり、そのためには従来
のSiO2やAL2O3に代わる誘電率がより大きい材
料が必要とされている。(Prior Art) As elements in electronic components and integrated circuits become smaller and more integrated, demand for thin film capacitors is increasing. These thin film capacitors are required to have a small area and a large capacity, which requires a material with a higher dielectric constant to replace the conventional SiO 2 and AL 2 O 3 .
BaTiO3に代表される強誘電体のペロブスカイ
ト型酸化物材料はバルクで数百から数千の誘電率
を有し、薄膜キヤパシタ材料として有望である。
1971年発行のプロシーデイング・オブ・アイ・イ
ー・イー・イー（Proceeding of the IEEE）第
59巻10号1440〜1447頁にRFマグネトロンスパツ
タ法によつて成膜したBaTiO3膜の誘電特性が報
告されており、約400の誘電率が得られている。
このとき、500〜1000℃の基板温度あるいは熱処
理温度で膜を結晶化させることによつて高い誘電
率を得ることができる。また、下部電極には高融
点金属であるPt−Ph合金が用いられ、高温での
電極の酸化を防いでいる。 Ferroelectric perovskite-type oxide materials represented by BaTiO 3 have a bulk dielectric constant of several hundred to several thousand, and are promising as thin-film capacitor materials.
Proceedings of the IEEE, published in 1971.
Vol. 59, No. 10, pp. 1440-1447 reports the dielectric properties of a BaTiO 3 film formed by the RF magnetron sputtering method, and a dielectric constant of about 400 is obtained.
At this time, a high dielectric constant can be obtained by crystallizing the film at a substrate temperature or heat treatment temperature of 500 to 1000°C. In addition, the lower electrode uses a Pt-Ph alloy, which is a high-melting point metal, to prevent the electrode from oxidizing at high temperatures.
（発明が解決しようとする課題）
前述のごとく、高温の基板温度あるいは熱処理
によつて高い誘電率のBaTiO3膜を作製すること
ができるが、膜の結晶化にともなうリーク電流の
増大、絶縁耐圧の低下および耐圧分布の分散の問
題が薄膜キヤパシタ素子としての実用化が進まな
い原因であつた。一般に膜の結晶化が進むと結晶
粒の形成によりリーク電流の増大、絶縁性の低下
が現れるのは知られている。(Problems to be Solved by the Invention) As mentioned above, a BaTiO 3 film with a high dielectric constant can be fabricated by using a high substrate temperature or heat treatment, but due to the crystallization of the film, the leakage current increases and the dielectric breakdown voltage increases. The problems of a decrease in the voltage and a dispersion of the breakdown voltage distribution have been the reasons why the practical application of thin film capacitor elements has not progressed. It is generally known that as the crystallization of a film progresses, leakage current increases and insulation properties deteriorate due to the formation of crystal grains.
本発明は上記の従来技術の問題を解決し、リー
ク電流が少なく、絶縁耐圧とその分布に優れた高
誘電率薄膜キヤパシタを提供することを目的とす
る。 It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a high dielectric constant thin film capacitor with low leakage current and excellent dielectric strength and its distribution.
（課題を解決するための手段）
本発明は基板上に下部電極膜が形成され、該下
部電極膜上に絶縁体膜が形成され、該絶縁体膜上
に誘電体膜が形成され、該誘電体膜上に上部電極
膜が形成される構造において、下部電極膜が高融
点貴金属のPtまたはPdの少なくとも一方を主成
分とし、絶縁体膜がTiO2あるいはTa2O5のうち
の１以上からなることを特徴とする薄膜キヤパシ
タと、TiまたはTaの少なくとも一方を含み、Pt
またはPdの１以上を主成分とする下部電極上に
誘電体膜を形成する際、または形成後、少なくと
も該下部電極を所定の温度下におくことを特徴と
する薄膜キヤパシタの製造方法である。(Means for Solving the Problems) In the present invention, a lower electrode film is formed on a substrate, an insulating film is formed on the lower electrode film, a dielectric film is formed on the insulating film, and the dielectric film is formed on the lower electrode film. In a structure in which an upper electrode film is formed on a body film, the lower electrode film is mainly composed of at least one of Pt or Pd, which is a high melting point noble metal, and the insulating film is made of one or more of TiO 2 or Ta 2 O 5 . A thin film capacitor comprising at least one of Ti or Ta, Pt
Alternatively, there is a method for manufacturing a thin film capacitor, characterized in that at least the lower electrode is placed at a predetermined temperature during or after forming a dielectric film on the lower electrode containing one or more of Pd as a main component.
（実施例）
以下、本発明の一実施例について図面を参照し
て説明する。第１図は本実施例の薄膜キヤパシタ
の構造図で、サフアイア基板１上に下部電極とし
てPd膜２が形成され、Pd膜上に絶縁体層のTiO2
膜３が形成され、TiO2膜上に誘導体のBaTiO3膜
４が形成され、その上に上部電極のAl膜５が形
成されている。(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a structural diagram of the thin film capacitor of this example, in which a Pd film 2 is formed as a lower electrode on a sapphire substrate 1, and an insulating layer of TiO 2 is formed on the Pd film.
A film 3 is formed, a dielectric BaTiO 3 film 4 is formed on the TiO 2 film, and an Al film 5 as an upper electrode is formed thereon.
まず、DCスパツタ法による10原子％のTiを含
むPd膜をサフアイア基板に0.3μm成膜した。
BaTiO3膜は高周波マグネトロンスパツタ法で
0.5μmの膜厚のものを作製した。化学量論組成の
粉末ターゲツトを用い、Ar−O2混合ガスで、基
板温度600℃で行つた。このBaTiO3成膜の間に
Pd膜中のTiはPd膜とBaTiO3膜との界面に拡散
し、そこで酸化してTiO2の絶縁体層が形成され
る。上部電極には0.5μmのAlをDCスパツタ法に
より成膜した。本キヤパシタの有効面積は３×５
mm2である。 First, a 0.3 μm thick Pd film containing 10 atomic % Ti was deposited on a sapphire substrate using the DC sputtering method.
BaTiO 3 film is made by high frequency magnetron sputtering method.
A film with a thickness of 0.5 μm was fabricated. A powder target with a stoichiometric composition was used, an Ar-O 2 mixed gas was used, and the substrate temperature was 600°C. During this BaTiO 3 film formation
Ti in the Pd film diffuses to the interface between the Pd film and the BaTiO 3 film, where it is oxidized to form a TiO 2 insulator layer. A 0.5 μm Al film was formed on the upper electrode by DC sputtering. The effective area of this capacitor is 3×5
mm2 .
つぎにPd膜上に直接成膜した場合と本方法に
より成膜した場合のBaTiO3膜の特性の違いにつ
いて述べる。第２図ａはPd膜上に直接成膜した
BaTiO3膜の、ｂは本方法により作製した
BaTiO3膜の絶縁破壊強度のヒストグラムであ
る。絶縁破壊強度は１×10-4Ａ／cm2の電流が流れ
たときの電界強度と定義した。絶縁破壊強度は本
方法の方が約３倍も大きく、その分布にもばらつ
きがなく優れた絶縁特性を示している。 Next, we will discuss the differences in the characteristics of the BaTiO 3 film when it is deposited directly on the Pd film and when it is deposited using this method. Figure 2a shows the film formed directly on the Pd film.
Of the BaTiO 3 film, b was prepared by this method.
This is a histogram of dielectric breakdown strength of BaTiO 3 film. The dielectric breakdown strength was defined as the electric field strength when a current of 1×10 −4 A/cm 2 flows. The dielectric breakdown strength of this method is approximately three times higher, and its distribution is consistent, indicating excellent insulation properties.
本方法において、TiO2膜を形成するためには
400℃以上の基板温度で誘電体膜を成膜する必要
があるが、Pd膜の耐熱性を考慮すると1000℃以
下であることが望ましい。 In this method, in order to form a TiO 2 film,
Although it is necessary to form the dielectric film at a substrate temperature of 400°C or higher, the temperature is preferably 1000°C or lower considering the heat resistance of the Pd film.
また、TiO2が形成されない300℃で誘電体膜を
成膜した後、酸素を含む大気圧の雰囲気において
500℃の温度で熱処理を行うことによりTiO2膜の
形成ができ、絶縁特性に優れた高誘電率薄膜キヤ
パシタを作製できた。従つて、絶縁体層の形成方
法として、該誘電体成膜後に酸素を含む大気圧の
雰囲気における500℃以上1000℃以下の温度での
熱処理を行つてもよい。 In addition, after forming the dielectric film at 300°C, where TiO 2 is not formed, it is deposited in an atmosphere containing oxygen at atmospheric pressure.
By performing heat treatment at a temperature of 500°C, we were able to form a TiO 2 film and create a high dielectric constant thin film capacitor with excellent insulation properties. Therefore, as a method for forming the insulator layer, heat treatment may be performed at a temperature of 500° C. or more and 1000° C. or less in an oxygen-containing atmosphere at atmospheric pressure after forming the dielectric film.
さらに、300℃で誘電体膜を成膜した後、４×
10-4Torrの酸素ガスECRプラズマ中で300℃の温
度て熱処理を行うことによりTiO2膜の形成がで
き、絶縁特性に優れた高誘電率薄膜キヤパシタを
作製できた。従つて、絶縁体層の形成方法とし
て、該誘電体成膜後に酸素プラズマ雰囲気での
300℃以上1000℃以下の温度での熱処理を行つて
もよい。なおこれらの熱処理は10分〜120分程度
の範囲で行なうことができる。 Furthermore, after forming a dielectric film at 300℃,
A TiO 2 film was formed by heat treatment at a temperature of 300°C in an oxygen gas ECR plasma of 10 -4 Torr, and a high dielectric constant thin film capacitor with excellent insulation properties was fabricated. Therefore, as a method for forming an insulator layer, after forming the dielectric film, it is necessary to form the dielectric layer in an oxygen plasma atmosphere.
Heat treatment may be performed at a temperature of 300°C or higher and 1000°C or lower. Note that these heat treatments can be performed for about 10 minutes to 120 minutes.
Tiの代わりにTaを、あるいはPdの代わりにPt
を用いた場合においてもまたTi，PdとPtを同時
に含む場合であつても本実施例と同じ条件で同様
の優れた絶縁特性が得られた。Ti，Taの添加量
は５〜50原子％の範囲で可能である。この範囲外
では絶縁層が薄すぎたり、または誘電体膜の実質
的な誘電率が低下する。 Ta instead of Ti or Pt instead of Pd
Even when Ti, Pd, and Pt were used at the same time, the same excellent insulation properties were obtained under the same conditions as in this example. The amount of Ti and Ta added can range from 5 to 50 atomic percent. Outside this range, the insulating layer will be too thin or the substantial dielectric constant of the dielectric film will decrease.
（発明の効果）
本発明は以上説明したように、薄膜キヤパシタ
の下部電極と誘電体膜との界面に誘電率が20〜40
の良質のTiO2やTa2O5の絶縁層を形成したので、
リーク電流が少なく、絶縁特性に優れた高誘電率
薄膜キヤパシタを提供することができる。(Effects of the Invention) As explained above, the present invention has a dielectric constant of 20 to 40 at the interface between the lower electrode of the thin film capacitor and the dielectric film.
Since we formed an insulating layer of high quality TiO 2 or Ta 2 O 5 ,
A high dielectric constant thin film capacitor with low leakage current and excellent insulation properties can be provided.
第１図は本発明における実施例の薄膜キヤパシ
タの断側面図、第２図ａ，ｂは絶縁破壊強度のヒ
ストグラムを示す図。
１はサフアイア基板、２はPd下部電極膜、３
はTiO2絶縁体膜、４はBaTiO3誘電体膜、５は
Al上部電極。
FIG. 1 is a cross-sectional side view of a thin film capacitor according to an embodiment of the present invention, and FIGS. 2a and 2b are diagrams showing histograms of dielectric breakdown strength. 1 is sapphire substrate, 2 is Pd lower electrode film, 3
is TiO 2 insulator film, 4 is BaTiO 3 dielectric film, 5 is
Al upper electrode.
Claims (1)
膜上に絶縁体膜が形成され、該絶縁体膜上に誘電
体膜が形成され、該誘電体膜上に上部電極膜が形
成される構造において、下部電極膜が高融点貴金
属のPtまたはPdの少なくとも一方を主成分とし、
絶縁体膜がTiO2あるいはTa2O5のうちの１以上
からなることを特徴とする薄膜キヤパシタ。 ２ TiまたはTaの少なくとも一方を含み、Ptま
たはPdの１以上を主成分とする下部電極上に誘
電体膜を形成する際、または形成後、少なくとも
該下部電極を所定の温度下におくことを特徴とす
る薄膜キヤパシタの製造方法。[Claims] 1. A lower electrode film is formed on a substrate, an insulating film is formed on the lower electrode film, a dielectric film is formed on the insulating film, and an upper electrode film is formed on the dielectric film. In the structure in which the electrode film is formed, the lower electrode film contains at least one of Pt or Pd, which is a high melting point noble metal, as a main component,
A thin film capacitor characterized in that the insulating film is made of one or more of TiO 2 and Ta 2 O 5 . 2. When forming a dielectric film on a lower electrode containing at least one of Ti or Ta and having one or more of Pt or Pd as a main component, or after forming the dielectric film, at least place the lower electrode under a predetermined temperature. Characteristic method for manufacturing thin film capacitors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21677588A JPH0265111A (en) | 1988-08-30 | 1988-08-30 | Thin-film capacitor and manufacture thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21677588A JPH0265111A (en) | 1988-08-30 | 1988-08-30 | Thin-film capacitor and manufacture thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0265111A JPH0265111A (en) | 1990-03-05 |
| JPH0587164B2 true JPH0587164B2 (en) | 1993-12-15 |
Family
ID=16693701
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21677588A Granted JPH0265111A (en) | 1988-08-30 | 1988-08-30 | Thin-film capacitor and manufacture thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0265111A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04159680A (en) * | 1990-10-24 | 1992-06-02 | Seiko Instr Inc | Ferroelectric body thin-film element |
| JP2912457B2 (en) * | 1991-02-01 | 1999-06-28 | 日本板硝子株式会社 | Thin film capacitors |
| US5471364A (en) * | 1993-03-31 | 1995-11-28 | Texas Instruments Incorporated | Electrode interface for high-dielectric-constant materials |
| US5933316A (en) * | 1993-08-02 | 1999-08-03 | Motorola Inc. | Method for forming a titanate thin film on silicon, and device formed thereby |
-
1988
- 1988-08-30 JP JP21677588A patent/JPH0265111A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0265111A (en) | 1990-03-05 |
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