JP3182889B2 - Ferroelectric device - Google Patents
Ferroelectric deviceInfo
- Publication number
- JP3182889B2 JP3182889B2 JP16786092A JP16786092A JP3182889B2 JP 3182889 B2 JP3182889 B2 JP 3182889B2 JP 16786092 A JP16786092 A JP 16786092A JP 16786092 A JP16786092 A JP 16786092A JP 3182889 B2 JP3182889 B2 JP 3182889B2
- Authority
- JP
- Japan
- Prior art keywords
- ferroelectric
- titanate
- film
- oxide
- ferroelectric film
- 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
Landscapes
- Formation Of Insulating Films (AREA)
- Semiconductor Integrated Circuits (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は強誘電体装置の構造に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a ferroelectric device.
【０００２】[0002]
【従来の技術】従来、強誘電体装置は、文献R.Womack a
nd D.Tolsch, Technical Digest of ISSCC 89,p.242(19
89).に示されているごとく、基体表面に形成された電極
上に強誘電体膜と電極とが形成されて成るのが通例であ
った。2. Description of the Related Art Conventionally, a ferroelectric device has been disclosed in R. Womack a
nd D. Tolsch, Technical Digest of ISSCC 89, p. 242 (19
89). In general, a ferroelectric film and an electrode are formed on an electrode formed on a substrate surface.
【０００３】[0003]
【発明が解決しようとする課題】しかし、上記従来技術
によると、強誘電体特性が劣化したり、リーク電流が大
きい等の課題があった。However, according to the above prior art, there have been problems such as deterioration of ferroelectric characteristics and large leakage current.
【０００４】本発明は、かかる従来技術の課題を解決
し、強誘電体特性の劣化の無い新しい強誘電体装置構造
を提供する事、およびリーク電流の小さい新しい強誘電
体装置構造を提供する事を目的とする。The present invention solves the problems of the prior art and provides a new ferroelectric device structure without deterioration of ferroelectric characteristics and a new ferroelectric device structure with small leakage current. With the goal.
【０００５】[0005]
【課題を解決するための手段】上記従来技術の課題を解
決し、上記目的を達成するために、本発明は、強誘電体
装置に関し、基体と、前記基体上に形成された第１の電
極と、前記第１の電極上に形成された第１の強誘電体膜
と、前記第１の強誘電体膜上に形成された種結晶と、前
記種結晶上に形成された第２の強誘電体膜と、前記第２
の強誘電体膜上に形成された第２の電極とを有すること
を特徴とする。また、上記構成において、前記種結晶
は、タングステン、モリブデンから選択されることを特
徴とする。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art and to achieve the above object, the present invention relates to a ferroelectric device, and relates to a base and a first electrode formed on the base. A first ferroelectric film formed on the first electrode, a seed crystal formed on the first ferroelectric film, and a second ferroelectric film formed on the seed crystal. A dielectric film;
And a second electrode formed on the ferroelectric film. In the above structure, the seed crystal is selected from tungsten and molybdenum.
【０００６】[0006]
【作用】緩衝層は強誘電体結晶のストイッキオメトリー
を得る作用と、強誘電体膜に流れる電流を抑制する作用
がある。The buffer layer has a function of obtaining stoichiometry of the ferroelectric crystal and a function of suppressing a current flowing through the ferroelectric film.
【０００７】[0007]
【実施例】以下、実施例により、本発明を詳述する。The present invention will be described below in detail with reference to examples.
【０００８】図１は、本発明の一実施例を示す強誘電体
装置の断面図である。すなわち、シリコン等の半導体基
板１０１等の表面に形成したシリコン酸化膜やシリコン
窒化膜等から成る絶縁膜１０２等から成る基体表面に形
成した白金等の導電体から成る電極１０３の表面にチタ
ン酸ストロンチュウム、酸化マグネシュウム、アルミ
ナ、酸化チタン、酸化タンタル、あるいは酸化ニオブ等
から成る緩衝層１０３をスパッタ法やＣＶＤ法等により
１０ｎｍ〜１００ｎｍ厚さ程度形成し、該緩衝層１０３
上にチタン酸ジルコニュウム鉛、チタン酸ジルコニュウ
ム・ランタン鉛、チタン酸ジルコニュウム鉄・鉛、チタ
ン酸バリュウム、チタン酸ビスマスあるいはチタン酸ゲ
ルマニュウム鉛等から成る強誘電体膜１０５をスパッタ
法やＣＶＤ法等で２０ｎｍ〜３０ｎｍ厚さ程度形成し、
該強誘電体膜１０５上に白金等の導電体から成る電極１
０６を形成し、強誘電体装置となしたものである。尚、
本実施例の場合、緩衝層１０３には強誘電体膜１０５と
格子定数が類似した材料を用いる必要があるが、必ずし
もチタン酸ストロンチュウム、酸化マグネシュウム、ア
ルミナ、酸化チタン、酸化タンタル、あるいは酸化ニオ
ブ等のごとき絶縁体である必要はなく、タングステンや
モリブデン等の金属体であっても良い。本例ではペロブ
スカイト結晶構造をとりがちな強誘電体を例示したの
で、該ペロブスカイト結晶構造の格子定数と類似した格
子定数を持つ絶縁体を例示したもので、緩衝層１０３の
必要条件は強誘電体膜１０５を酸素欠損等が無く、スト
イッキオメトリーの良好な膜と成すための種結晶である
事である。この様に強誘電体膜１０５を酸素欠損等が無
く、ストイッキオメトリーの良好な膜と成すと、強誘電
体膜１０５の強誘電体特性の劣化を防止でき、且つリー
ク電流を減少する事ができる。但し、緩衝層１０３に絶
縁体を用いる事は、リーク電流を減少するのに有効であ
る。FIG. 1 is a sectional view of a ferroelectric device showing one embodiment of the present invention. That is, strontium titanate is formed on the surface of an electrode 103 made of a conductor such as platinum formed on a surface of a base made of an insulating film 102 made of a silicon oxide film or a silicon nitride film formed on a surface of a semiconductor substrate 101 made of silicon or the like. A buffer layer 103 made of, for example, titanium, magnesium oxide, alumina, titanium oxide, tantalum oxide, or niobium oxide is formed to a thickness of about 10 nm to 100 nm by a sputtering method, a CVD method, or the like.
A ferroelectric film 105 made of lead zirconium titanate, zirconium titanate / lanthanum lead, zirconium iron titanate / lead, barium titanate, bismuth titanate, germanium lead titanate, or the like is formed to a thickness of 20 nm by sputtering or CVD. About 30 nm thick,
An electrode 1 made of a conductor such as platinum is formed on the ferroelectric film 105.
No. 06 is formed to form a ferroelectric device. still,
In the case of this embodiment, it is necessary to use a material having a lattice constant similar to that of the ferroelectric film 105 for the buffer layer 103; however, strontium titanate, magnesium oxide, alumina, titanium oxide, tantalum oxide, or oxide It does not need to be an insulator such as niobium, but may be a metal such as tungsten or molybdenum. In this example, a ferroelectric substance which tends to have a perovskite crystal structure is illustrated. Therefore, an insulator having a lattice constant similar to the lattice constant of the perovskite crystal structure is illustrated. It is a seed crystal for forming the film 105 without oxygen deficiency or the like and excellent in stoichiometry. By forming the ferroelectric film 105 without oxygen deficiency or the like and having good stoichiometry, deterioration of the ferroelectric characteristics of the ferroelectric film 105 can be prevented and leakage current can be reduced. Can be. However, using an insulator for the buffer layer 103 is effective in reducing leakage current.
【０００９】図２は、本発明の他の実施例を示す強誘電
体装置の断面図である。すなわち、シリコン等の半導体
基板２０１等の表面に形成したシリコン酸化膜やシリコ
ン窒化膜等から成る絶縁膜２０２等から成る基体表面に
形成した白金等の導電体から成る電極２０３の表面にチ
タン酸ジルコニュウム鉛、チタン酸ジルコニュウム・ラ
ンタン鉛、チタン酸ジルコニュウム鉄・鉛、チタン酸バ
リュウム、チタン酸ビスマスあるいはチタン酸ゲルマニ
ュウム鉛等から成る強誘電体膜２０４をスパッタ法やＣ
ＶＤ法等で２０ｎｍ〜３０ｎｍ厚さ程度形成し、該強誘
電体膜２０４上にチタン酸ストロンチュウム、酸化マグ
ネシュウム、アルミナ、酸化チタン、酸化タンタル、あ
るいは酸化ニオブ等から成る緩衝層２０５をスパッタ法
やＣＶＤ法等により１０ｎｍ〜１００ｎｍ厚さ程度形成
し、該緩衝層２０５上に白金等の導電体から成る電極２
０６を形成し、強誘電体装置となしたものである。尚、
本実施例の緩衝層２０５はリーク電流の低減を図るため
のものであるので、絶縁体である必要はあるが、必ずし
もチタン酸ストロンチュウム、酸化マグネシュウム、ア
ルミナ、酸化チタン、酸化タンタル、あるいは酸化ニオ
ブ等のみならず酸化シリコンや窒化シリコン等のその他
の絶縁膜であっても良く、更に、該緩衝層２０５は強誘
電体膜２０４の側面にまで延在して形成されても良い。FIG. 2 is a sectional view of a ferroelectric device showing another embodiment of the present invention. That is, zirconium titanate is formed on a surface of an electrode 203 made of a conductor such as platinum formed on a surface of a base made of an insulating film 202 made of a silicon oxide film or a silicon nitride film formed on a surface of a semiconductor substrate 201 made of silicon or the like. A ferroelectric film 204 made of lead, zirconium titanate / lanthanum lead, zirconium iron / lead titanate, barium titanate, bismuth titanate or germanium lead titanate is formed by sputtering or C
A buffer layer 205 made of strontium titanate, magnesium oxide, alumina, titanium oxide, tantalum oxide, niobium oxide, or the like is formed on the ferroelectric film 204 by a sputtering method. An electrode 2 made of a conductor such as platinum is formed on the buffer layer 205 to a thickness of about 10 nm to 100 nm by, for example,
No. 06 is formed to form a ferroelectric device. still,
The buffer layer 205 of this embodiment is intended to reduce the leak current, and therefore needs to be an insulator, but is not necessarily strontium titanate, magnesium oxide, alumina, titanium oxide, tantalum oxide, or oxidized oxide. Not only niobium but also other insulating films such as silicon oxide and silicon nitride may be used. Further, the buffer layer 205 may be formed to extend to the side surface of the ferroelectric film 204.
【００１０】図３は、本発明のその他の実施例を示す強
誘電体装置の断面図である。すなわち、シリコン等の半
導体基板３０１等の表面に形成したシリコン酸化膜やシ
リコン窒化膜等から成る絶縁膜３０２等から成る基体表
面に、チタン酸ジルコニュウム鉛、チタン酸ジルコニュ
ウム・ランタン鉛、チタン酸ジルコニュウム鉄・鉛、チ
タン酸バリュウム、チタン酸ビスマスあるいはチタン酸
ゲルマニュウム鉛等から成る強誘電体膜３０４をスパッ
タ法やＣＶＤ法等で１０ｎｍ〜１５ｎｍ厚さ程度形成
し、該強誘電体膜３０４上にチタン酸ストロンチュウ
ム、酸化マグネシュウム、アルミナ、酸化チタン、酸化
タンタル、あるいは酸化ニオブ等から成る緩衝層３０５
をスパッタ法やＣＶＤ法等により１０ｎｍ〜１００ｎｍ
厚さ程度形成し、該緩衝層３０５上チタン酸ジルコニュ
ウム鉛、チタン酸ジルコニュウム・ランタン鉛、チタン
酸ジルコニュウム鉄・鉛、チタン酸バリュウム、チタン
酸ビスマスあるいはチタン酸ゲルマニュウム鉛等から成
る強誘電体膜３０６をスパッタ法やＣＶＤ法等で１０ｎ
ｍ〜１５ｎｍ厚さ程度形成し、該強誘電体膜３０６上に
白金等の導電体から成る電極３０７を形成し、強誘電体
装置となしたものである。FIG. 3 is a sectional view of a ferroelectric device according to another embodiment of the present invention. That is, zirconium lead titanate, zirconium / lanthanum lead titanate, zirconium titanate iron, etc. are formed on the surface of a base made of an insulating film 302 made of a silicon oxide film or a silicon nitride film formed on the surface of a semiconductor substrate 301 made of silicon or the like. Forming a ferroelectric film 304 made of lead, barium titanate, bismuth titanate or lead germanium titanate to a thickness of about 10 to 15 nm by a sputtering method, a CVD method or the like, and forming a titanic acid film on the ferroelectric film 304; Buffer layer 305 made of strontium, magnesium oxide, alumina, titanium oxide, tantalum oxide, niobium oxide, or the like
From 10 nm to 100 nm by sputtering, CVD, etc.
A ferroelectric film 306 formed to a thickness of about 300 nm on the buffer layer 305 and made of lead zirconium titanate, lead zirconium titanate / lanthanum titanate, iron lead zirconium titanate, barium titanate, bismuth titanate or germanium lead titanate. 10n by sputtering, CVD, etc.
An electrode 307 made of a conductor such as platinum is formed on the ferroelectric film 306 so as to form a ferroelectric device.
【００１１】尚、本実施例の場合、緩衝層３０５には強
誘電体膜３０６あるいは３０４と格子定数が類似した材
料を用いる必要があるが、必ずしもチタン酸ストロンチ
ュウム、酸化マグネシュウム、アルミナ、酸化チタン、
酸化タンタル、あるいは酸化ニオブ等のごとき絶縁体で
ある必要はなく、タングステンやモリブデン等の金属体
であっても良い。本例ではペロブスカイト結晶構造をと
りがちな強誘電体を例示したので、該ペロブスカイト結
晶構造の格子定数と類似した格子定数を持つ絶縁体を例
示したもので、緩衝層３０５の必要条件は強誘電体膜３
０６を酸素欠損等が無く、ストイッキオメトリーの良好
な膜と成すための種結晶である事である。この様に強誘
電体膜３０６を酸素欠損等が無く、ストイッキオメトリ
ーの良好な膜と成すと、強誘電体膜３０６の強誘電体特
性の劣化を防止でき、且つリーク電流を減少する事がで
きる。但し、緩衝層３０５に絶縁体を用いる事は、リー
ク電流を減少するのに有効である。In this embodiment, the buffer layer 305 must be made of a material having a lattice constant similar to that of the ferroelectric film 306 or 304. However, strontium titanate, magnesium oxide, alumina, oxide Titanium,
It is not necessary to be an insulator such as tantalum oxide or niobium oxide, but may be a metal body such as tungsten or molybdenum. In this example, a ferroelectric which tends to have a perovskite crystal structure is illustrated, and therefore, an insulator having a lattice constant similar to the lattice constant of the perovskite crystal structure is illustrated. Membrane 3
No. 06 is a seed crystal for forming a film free of oxygen deficiency or the like and excellent in stoichiometry. As described above, when the ferroelectric film 306 is formed without oxygen deficiency and has good stoichiometry, deterioration of the ferroelectric characteristics of the ferroelectric film 306 can be prevented and leakage current can be reduced. Can be. However, using an insulator for the buffer layer 305 is effective in reducing the leak current.
【００１２】[0012]
【発明の効果】本発明により、強誘電体特性の劣化の無
い強誘電体装置、およびリーク電流の小さい強誘電体装
置を提供する事ができる効果がある。According to the present invention, it is possible to provide a ferroelectric device having no deterioration in ferroelectric characteristics and a ferroelectric device having a small leak current.
【図面の簡単な説明】[Brief description of the drawings]
【図１】 本発明の一実施例を示す強誘電体装置の断面
図である。FIG. 1 is a sectional view of a ferroelectric device showing one embodiment of the present invention.
【図２】 本発明の他の実施例を示す強誘電体装置の断
面図である。FIG. 2 is a sectional view of a ferroelectric device according to another embodiment of the present invention.
【図３】 本発明のその他の実施例を示す強誘電体装置
の断面図である。FIG. 3 is a sectional view of a ferroelectric device according to another embodiment of the present invention.
１０１、２０１、３０１・・・半導体基板 １０２、２０２、３０２・・・絶縁膜 １０３、１０６、２０３、２０６、３０３、３０７・・
・電極 １０４、２０５、３０５・・・緩衝層 １０５、２０４、３０４、３０６・・・強誘電体膜101, 201, 301 ... semiconductor substrate 102, 202, 302 ... insulating film 103, 106, 203, 206, 303, 307 ...
-Electrodes 104, 205, 305: Buffer layer 105, 204, 304, 306: Ferroelectric film
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 21/822 H01L 27/04 H01L 27/10 - 27/115 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) H01L 21/822 H01L 27/04 H01L 27/10-27/115
Claims (2)
ンから選択されることを特徴とする強誘電体装置。 2. The method according to claim 1, wherein the seed crystal is tungsten, molybdenum or tungsten.
A ferroelectric device selected from the group consisting of:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16786092A JP3182889B2 (en) | 1992-06-25 | 1992-06-25 | Ferroelectric device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16786092A JP3182889B2 (en) | 1992-06-25 | 1992-06-25 | Ferroelectric device |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11180754A Division JP2000082784A (en) | 1999-06-25 | 1999-06-25 | Ferroelectric device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0613542A JPH0613542A (en) | 1994-01-21 |
| JP3182889B2 true JP3182889B2 (en) | 2001-07-03 |
Family
ID=15857433
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16786092A Expired - Lifetime JP3182889B2 (en) | 1992-06-25 | 1992-06-25 | Ferroelectric device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3182889B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2755174B2 (en) * | 1994-06-21 | 1998-05-20 | 日本電気株式会社 | Ferroelectric capacitor and memory cell structure |
| JP2703206B2 (en) * | 1994-09-30 | 1998-01-26 | 三星電子株式会社 | Ferroelectric capacitor and method of manufacturing the same |
| KR100747369B1 (en) | 1999-09-30 | 2007-08-07 | 로무 가부시키가이샤 | Nonvolatile memory |
| KR100455287B1 (en) * | 2002-02-28 | 2004-11-06 | 삼성전자주식회사 | Capacitor for semiconductor device, manufacturing method thereof and electronic device employing the capacitor |
| JP2006278664A (en) * | 2005-03-29 | 2006-10-12 | Toyobo Co Ltd | Multilayer dielectric film for thin film capacitor and its deposition process |
| JP2007251210A (en) * | 2007-06-20 | 2007-09-27 | Texas Instr Inc <Ti> | Capacitor and method of forming the same |
-
1992
- 1992-06-25 JP JP16786092A patent/JP3182889B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0613542A (en) | 1994-01-21 |
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