JP2000307077A - Manufacture of thin film capacitor - Google Patents
Manufacture of thin film capacitorInfo
- Publication number
- JP2000307077A JP2000307077A JP11112589A JP11258999A JP2000307077A JP 2000307077 A JP2000307077 A JP 2000307077A JP 11112589 A JP11112589 A JP 11112589A JP 11258999 A JP11258999 A JP 11258999A JP 2000307077 A JP2000307077 A JP 2000307077A
- Authority
- JP
- Japan
- Prior art keywords
- oxide film
- forming
- dielectric constant
- high dielectric
- film layer
- 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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- Semiconductor Integrated Circuits (AREA)
- Semiconductor Memories (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、高集積度の半導体
装置に用いられる薄膜キャパシタの製造方法に関する。The present invention relates to a method for manufacturing a thin film capacitor used for a highly integrated semiconductor device.
【０００２】[0002]
【従来の技術】ＤＲＡＭ（Ｄｙｎａｍｉｃ Ｒａｎｄｏ
ｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｉｅｓ）をはじめとする
半導体記憶素子の集積度の向上に伴い、容量絶縁膜とし
て、シリコン酸化膜やシリコン窒化膜に代わり、（Ｂ
ａ，Ｓｒ）ＴｉＯ3をはじめとする高誘電率酸化物が盛
んに検討されている。2. Description of the Related Art DRAM (Dynamic Land)
With the improvement in the integration degree of semiconductor storage elements such as m Access Memories, instead of a silicon oxide film or a silicon nitride film as a capacitive insulating film, (B
High dielectric constant oxides such as a, Sr) TiO 3 have been actively studied.
【０００３】また、容量膜にこのような高誘電率酸化物
を使用する際に、従来まで用いられてきたポリシリコン
電極は、電極と高誘電率酸化物との界面が酸化する問い
得ような問題があって、このような容量絶縁膜を直ちに
使用することができない。In addition, when such a high dielectric constant oxide is used for a capacitor film, a polysilicon electrode which has been conventionally used may be oxidized at an interface between the electrode and the high dielectric constant oxide. There is a problem that such a capacitor insulating film cannot be used immediately.
【０００４】さらに、電極についてもＰｔ、Ｒｕ等の金
属電極や導電性のある金属酸化物、ＴｉＮなどの導電性
窒化物の使用の検討が盛んに行われている。特にＲｕ及
びＩｒは、微細なエッチングが比較的容易であることか
ら、その期待が特に大きい。[0004] Further, with respect to electrodes, the use of metal electrodes such as Pt and Ru, conductive metal oxides, and conductive nitrides such as TiN has been actively studied. In particular, since Ru and Ir are relatively easy to perform fine etching, their expectations are particularly high.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記材
料は、エッチングが容易である反面、酸化耐性が低い。
そのため、このような高誘電率酸化膜層を酸素プラズマ
やＮ2Ｏなどの酸化力の強い酸素源を使用して成膜する
場合、下部電極材のＲｕ及びＩｒの表面酸化による核生
成が原因になって、凸凹が生じ、高温下では表面エッチ
ング荒れが生じる。However, the above materials are easy to etch, but have low oxidation resistance.
Therefore, when such a high dielectric constant oxide film layer is formed using an oxygen source having a strong oxidizing power such as oxygen plasma or N 2 O, nucleation due to surface oxidation of Ru and Ir of the lower electrode material is caused. And unevenness occurs, and surface etching becomes rough at high temperatures.
【０００６】例えば、半導体基板上にＴｉ、ＴｉＮ、Ｒ
ｕをスパッタ法により積層した下部電極を形成する処理
と、その後、（Ｂａ，Ｓｒ）Ｔｉ高誘電率膜をＥＣＲ−
ＣＶＤ法により下部電極上に形成し、その際、成膜開始
と同時にＯ2プラズマが照射状態でＢＳＴを所定の膜厚
まで形成する処理とを順次行い、その後、上部電極をス
パッタ法で形成する処理を行って高誘電率薄膜キャパシ
タが得られる。For example, Ti, TiN, R
forming a lower electrode in which a lower electrode is laminated by sputtering, and then depositing a (Ba, Sr) Ti high dielectric constant film on an ECR-
A process of forming a BST to a predetermined thickness in a state of being irradiated with O 2 plasma at the same time as the start of film formation is performed sequentially on the lower electrode by a CVD method, and then an upper electrode is formed by a sputtering method. The processing is performed to obtain a high dielectric constant thin film capacitor.
【０００７】このようにして得られたキャパシタのリー
ク特性を図４に示す。図４によれば、駆動電圧１Ｖ印加
時にリーク電流がキャパシタ特性として十分な１×１０
-8Ａ／ｃｍ2以下の特性が得られておらず、このような
特性では、リーク特性不良であり、デバイスに適用した
時に、そのデバイスには、動作上の問題が生ずる。FIG. 4 shows the leakage characteristics of the capacitor thus obtained. According to FIG. 4, when the driving voltage of 1 V is applied, the leakage current is 1 × 10
Characteristics of -8 A / cm 2 or less have not been obtained, and such characteristics are poor in leak characteristics, and when applied to a device, there is a problem in operation of the device.
【０００８】同様の問題は、酸化力の高いＮ2Ｏガスを
酸素源とする熱ＣＶＤ法を用いて形成した膜においても
確認されている。上記方法により製造した高誘電率薄膜
キャパシタをＳＥＭ観察、ＳＴＭ、ＥＤＸ測定等より検
討をしたところ、このようなリーク特性不良が生ずる原
因は、下部電極の表面荒れに起因していることが分かっ
た。The same problem has been confirmed in a film formed by a thermal CVD method using N 2 O gas having a high oxidizing power as an oxygen source. When the high dielectric constant thin film capacitor manufactured by the above method was examined by SEM observation, STM, EDX measurement, and the like, it was found that the cause of such a leak characteristic defect was caused by the surface roughness of the lower electrode. .
【０００９】この様な表面荒れが生ずる原因は、下部電
極最表面層に用いられた白金族元素であるＲｕの表面が
（Ｂａ，Ｓｒ）ＴｉＯ3高誘電率膜の成膜初期に酸化力
の強い酸素源により、表面酸化及びＲｕＯ4形成による
エッチングが生じたことによるものと考えられる。また
ＲｕＯ4などの形成は、チャンバーの汚染を引き起こす
ため、問題が非常に大きい。The reason for the occurrence of such surface roughness is that the surface of Ru, which is a platinum group element used for the outermost surface layer of the lower electrode, has an oxidizing power at the initial stage of forming a (Ba, Sr) TiO 3 high dielectric constant film. This is probably because the strong oxygen source caused etching by surface oxidation and formation of RuO 4 . Also, the formation of RuO 4 or the like is very problematic because it causes contamination of the chamber.
【００１０】本発明の目的は、下部電極材料の用いられ
た白金族元素であるＲｕ及びＩｒ表面の酸化による荒れ
の抑制が可能な薄膜キャパシタの製造方法を提供するこ
とにある。An object of the present invention is to provide a method of manufacturing a thin film capacitor capable of suppressing roughness due to oxidation of the surfaces of Ru and Ir, which are platinum group elements used for a lower electrode material.
【００１１】[0011]
【課題を解決するための手段】上記目的を達成するた
め、本発明による薄膜キャパシタの製造方法において
は、第１の酸化膜形成処理と、第２の酸化膜形成処理と
を有し、相対的に酸化力を変化させて白金族元素からな
る下部電極層上に高誘電率酸化膜層キャパシタを形成す
る薄膜キャパシタの製造方法であって、第１の酸化膜形
成処理は、酸化力を下げた雰囲気中で下部電極層上に第
１の高誘電率酸化膜層を形成する処理であり、第２の酸
化膜形成処理は、酸化力を上げた雰囲気中で、第１の高
誘電率酸化膜層上に、第２の高誘電率酸化膜層を形成す
る処理であり、次いで第２の高誘電率酸化膜層上に、上
部電極層を形成するものである。In order to achieve the above object, a method of manufacturing a thin film capacitor according to the present invention comprises a first oxide film forming process and a second oxide film forming process. A method of manufacturing a thin-film capacitor in which a high-dielectric-constant oxide film layer capacitor is formed on a lower electrode layer made of a platinum group element by changing the oxidizing force, wherein the first oxide film forming process reduces the oxidizing force. The first high dielectric constant oxide film is formed on the lower electrode layer in an atmosphere, and the second oxide film forming process is performed in an atmosphere having an increased oxidizing power. This is a process for forming a second high dielectric constant oxide film layer on the layer, and then forming an upper electrode layer on the second high dielectric constant oxide film layer.
【００１２】また、第１の酸化膜形成処理は、酸化力を
下げた雰囲気中で第１の高誘電率絶縁膜層を形成して、
下部電極材料表面の酸化による荒れ抑制する処理であ
り、第２の酸化膜形成処理は、酸化力を上げた雰囲気中
で第２の高誘電率酸化膜層を形成して第１の高誘電率絶
縁膜層の酸素欠損を補填する処理である。In the first oxide film forming process, the first high dielectric constant insulating film layer is formed in an atmosphere having reduced oxidizing power,
The second oxide film forming process is a process for forming a second high dielectric constant oxide film layer in an atmosphere having an increased oxidizing power to form a first high dielectric constant film. This is a process for filling oxygen vacancies in the insulating film layer.
【００１３】また、ＥＣＲ−ＣＶＤを用いる薄膜キャパ
シタの製造方法であって、第１の酸化膜形成処理は、Ｏ
2プラズマを未照射状態で第１の高誘電率酸化膜層を形
成する処理であり、第２の酸化膜形成処理は、Ｏ2プラ
ズマ照射状態で第２の高誘電率酸化膜層を形成する処理
である。In a method of manufacturing a thin film capacitor using ECR-CVD, the first oxide film forming process comprises the steps of:
(2) A process for forming a first high dielectric constant oxide film layer in a state where plasma is not irradiated, and a second oxide film forming process is for forming a second high dielectric constant oxide film layer in a state where O 2 plasma is irradiated. Processing.
【００１４】また、熱ＣＶＤを用いる薄膜キャパシタの
製造方法であって、第１の酸化膜形成処理は、Ｏ2ガス
を用いて第１の高誘電率酸化膜層を形成する処理であ
り、第２の酸化膜形成処理は、酸化力の高いＮ2Ｏガス
を用いて第２の高誘電率酸化膜層を形成する処理であ
る。In the method of manufacturing a thin film capacitor using thermal CVD, the first oxide film forming process is a process of forming a first high dielectric constant oxide film layer using O 2 gas. The second oxide film forming process is a process of forming a second high dielectric constant oxide film layer using N 2 O gas having high oxidizing power.
【００１５】また、第２の高誘電率酸化膜層は、第１の
高誘電率酸化膜の成膜後、大気に暴露することなく、所
望の膜厚まで形成する処理である。The second high-dielectric-constant oxide film layer is a process for forming the first high-dielectric-constant oxide film to a desired thickness after exposing the first high-dielectric-constant oxide film without exposing it to the atmosphere.
【００１６】また、第１の高誘電率絶縁膜層の形成時間
は１〜１５秒の範囲である。The formation time of the first high dielectric constant insulating film layer is in the range of 1 to 15 seconds.
【００１７】また、第２の高誘電率酸化膜層は、複数の
層の積層である。The second high-dielectric-constant oxide film layer is a laminate of a plurality of layers.
【００１８】Ｒｕ及びＩｒのような白金族元素を用いた
下部電極上に、酸化力を上げた雰囲気中で高誘電率酸化
膜層を形成した場合、下部電極の酸化による表面荒れが
生じるため、良好なリーク特性が得られないという問題
が生じる。When a high-dielectric-constant oxide film layer is formed on a lower electrode using a platinum group element such as Ru and Ir in an atmosphere having an increased oxidizing power, surface roughening due to oxidation of the lower electrode occurs. There is a problem that good leak characteristics cannot be obtained.
【００１９】また、Ｒｕ及びＩｒ下部電極上に酸化力を
下げた雰囲気中で単層の高誘電率酸化膜層を形成した場
合、高誘電率酸化膜中に多大な酸素欠損が生じるため、
良好なリーク特性を有するキャパシタが形成できないと
いう問題が生じる。Further, when a single high-dielectric-constant oxide film layer is formed on an Ru or Ir lower electrode in an atmosphere having reduced oxidizing power, a large amount of oxygen vacancies are generated in the high-dielectric-constant oxide film.
There is a problem that a capacitor having good leak characteristics cannot be formed.
【００２０】このように、キャパシタのリーク特性と高
誘電率酸化膜層の成膜初期に生じるＲｕ，Ｉｒ等の下部
電極の表面荒れとには、密接な関係があることが明らか
になったことから、本発明においては、高誘電率酸化膜
層の成膜初期に酸化力の低い層を形成する処理を追加し
たものである。As described above, it has been found that there is a close relationship between the leakage characteristics of the capacitor and the surface roughness of the lower electrode such as Ru and Ir generated at the initial stage of forming the high dielectric constant oxide film layer. Therefore, in the present invention, a process for forming a layer having low oxidizing power at the initial stage of forming a high dielectric constant oxide film layer is added.
【００２１】すなわち、酸化力を下げた雰囲気中で第１
の高誘電率絶縁膜層を形成することにより、下部電極材
料であるＲｕ及びＩｒ表面の酸化による荒れが抑制さ
れ、ついで、酸化力を上げた雰囲気中で第２の高誘電率
酸化膜層を形成することにより、第１の高誘電率絶縁膜
層の酸素欠損が補填され、酸素欠損によるリーク特性不
良は生じない。That is, in an atmosphere with reduced oxidizing power, the first
By forming the high dielectric constant insulating film layer of the above, roughness due to oxidation of the surface of Ru and Ir as the lower electrode material is suppressed, and then the second high dielectric constant oxide film layer is formed in an atmosphere having an increased oxidizing power. With the formation, oxygen vacancies in the first high-dielectric-constant insulating film layer are compensated for, and a leak characteristic defect due to oxygen vacancies does not occur.
【００２２】[0022]
【発明の実施の形態】以下に本発明による薄膜キャパシ
タの製造方法の実施形態を図によって説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a thin film capacitor according to the present invention will be described below with reference to the drawings.
【００２３】（実施形態１）図１は、本発明の第一の実
施形態を説明するための薄膜キャパシタの製造工程を工
程順に示す図である。図１（ａ）において、単結晶シリ
コン基板１０１上に、Ｔｉ、ＴｉＮ、Ｒｕ膜からなる下
部電極層１０２を化学気相成長法（ＣＶＤ法）或いはス
パッタ法を用いて順次形成する。(Embodiment 1) FIG. 1 is a diagram showing a manufacturing process of a thin film capacitor for explaining a first embodiment of the present invention in the order of steps. In FIG. 1A, a lower electrode layer 102 made of a Ti, TiN, or Ru film is sequentially formed on a single crystal silicon substrate 101 by using a chemical vapor deposition method (CVD method) or a sputtering method.
【００２４】本発明による薄膜キャパシタの製造方法に
おいては、第１の酸化膜形成処理と、第２の酸化膜形成
処理とを順次行い、第１の高誘電率酸化膜層を白金族元
素を用いた下部電極層上に形成し、次いでその上に第２
の高誘電率酸化膜層を積層する。各処理においては、相
対的に酸化力を変化させて成膜し、上、下部電極間に、
電気的特性に優れた高誘電率酸化膜キャパシタを形成す
るものである。In the method for manufacturing a thin film capacitor according to the present invention, a first oxide film forming process and a second oxide film forming process are sequentially performed, and the first high dielectric constant oxide film layer is formed using a platinum group element. Formed on the lower electrode layer, and then a second
Are stacked. In each process, the film is formed by changing the oxidizing power relatively, and between the upper and lower electrodes,
This is to form a high dielectric constant oxide film capacitor having excellent electric characteristics.
【００２５】図１（ｂ）において、第１の酸化膜形成処
理は、酸化力を下げた雰囲気中で下部電極１０２上に第
１の高誘電率酸化膜層１０３を形成する処理である。こ
の実施形態においては、第１の高誘電率酸化膜層１０３
である（Ｂａ，Ｓｒ）ＴｉＯ 3膜をＥＣＲ−ＣＶＤ法に
よるＯ2プラズマ未照射状態で１５秒間のＯ2ガスの供給
のみで形成する。In FIG. 1B, a first oxide film forming process is performed.
The reason is that the first electrode is placed on the lower electrode 102 in an atmosphere having reduced oxidizing power.
This is a process for forming one high dielectric constant oxide film layer 103. This
In the embodiment, the first high dielectric constant oxide film layer 103
(Ba, Sr) TiO ThreeECR-CVD method for film
OTwoO for 15 seconds without plasma irradiationTwoGas supply
Only formed with.
【００２６】第２の酸化膜形成処理は、酸化力を上げた
雰囲気中で、第１の高誘電率酸化膜層１０３上に、第２
の高誘電率酸化膜層１０４を形成する処理である。In the second oxide film forming process, the second oxide film is formed on the first high dielectric oxide film layer 103 in an atmosphere having an increased oxidizing power.
This is a process for forming the high dielectric constant oxide film layer 104 of FIG.
【００２７】この実施形態においては、図１（ｃ）に示
すように、第１の高誘電率酸化膜１０３の成膜後、Ｏ2
プラズマ照射状態で第２の高誘電率酸化膜層１０４であ
る（Ｂａ，Ｓｒ）ＴｉＯ3膜を、ＥＣＲ−ＣＶＤ法によ
るＯ2プラズマ照射状態で第１の高誘電率酸化膜１０３
の成膜後、大気に暴露することなく、所望の膜厚まで形
成した。In this embodiment, as shown in FIG. 1C, after the first high dielectric oxide film 103 is formed, O 2
Plasma irradiation state is a second high dielectric constant oxide layer 104 (Ba, Sr) a TiO 3 film, the first high dielectric constant oxide film O 2 plasma irradiation state by ECR-CVD method 103
After the film formation, a film was formed to a desired thickness without exposing the film to the atmosphere.
【００２８】最後に、図１（ｄ）に示すように、上部電
極層１０５であるＲｕ膜を化学気相成長法（ＣＶＤ法）
或いはスパッタ法により形成して、図示の積層構造の薄
膜キャパシタを得た。Finally, as shown in FIG. 1D, the Ru film as the upper electrode layer 105 is formed by a chemical vapor deposition (CVD) method.
Alternatively, a thin film capacitor having a laminated structure as shown in the figure was obtained by sputtering.
【００２９】図２は、上記実施形態により得られた薄膜
キャパシタ（実施例１）と、第１の高誘電率酸化膜層を
形成する処理を行わない従来法によって形成した薄膜キ
ャパシタ（従来例１）との電流−電圧特性を比較した図
である。FIG. 2 shows a thin film capacitor obtained by the above embodiment (Example 1) and a thin film capacitor formed by a conventional method without performing a process of forming a first high dielectric constant oxide film layer (Conventional Example 1). FIG. 7 is a diagram comparing current-voltage characteristics of FIG.
【００３０】従来例１によるときには、駆動電圧が１Ｖ
以下においてもリーク電流密度が大きく、このような薄
膜キャパシタを用いたデバイスは、動作上問題があるの
に対し、本実施形態による薄膜キャパシタ（実施例１）
によるときには、印加される駆動電圧が１．５Ｖにおい
てもリーク電流密度が１×１０-8Ａ／ｃｍ2以下の良好
なリーク特性を得ることができた。According to the conventional example 1, the driving voltage is 1 V
Also in the following, the leakage current density is large, and a device using such a thin film capacitor has a problem in operation. On the other hand, the thin film capacitor according to the present embodiment (Example 1)
In this case, good leak characteristics having a leak current density of 1 × 10 −8 A / cm 2 or less were obtained even when the applied driving voltage was 1.5 V.
【００３１】本実施形態によるときには、第１の高誘電
率絶縁膜層をＯ2プラズマ未照射状態のＯ2ガス供給のみ
で形成する処理を採用しているので、ＲｕのＯ2プラズ
マによるエッチング荒れが抑制され、薄膜キャパシタ
は、良好なリーク特性を示すという利点が得られる。[0031] When according to the present embodiment, because it uses a process of forming a first high-k insulating layer only by the O 2 gas supply of the O 2 plasma unirradiated state, rough etching by O 2 plasma Ru Is suppressed, and the thin film capacitor has an advantage of exhibiting good leak characteristics.
【００３２】上記の実施形態においては、第１の高誘電
率絶縁膜層の形成を１５秒間で行なったが、１０ｓｅｃ
〜６０ｓｅｃの範囲で検討した結果、同様の効果が得ら
れた。但し、時間が長くなるほど誘電特性が小さくなる
傾向が見られるため、第１の高誘電率絶縁膜層の形成時
間は、１〜１５秒程度の範囲内で行うのが望ましい。In the above embodiment, the formation of the first high-dielectric-constant insulating film layer was performed in 15 seconds.
As a result of studying in the range of 範 囲 60 sec, a similar effect was obtained. However, since the dielectric property tends to decrease as the time becomes longer, it is desirable that the formation time of the first high dielectric constant insulating film layer is set within a range of about 1 to 15 seconds.
【００３３】（実施形態２）前実施形態１では、高誘電
率酸化膜層の形成にＥＣＲ−ＣＶＤ法を適用した例を示
した。本発明は、熱ＣＶＤ法を適用することもできる。
以下、実施形態１と同じ図１を用いて、この実施形態の
構成を説明する。(Embodiment 2) In Embodiment 1, an example in which the ECR-CVD method is applied to the formation of a high dielectric constant oxide film layer has been described. In the present invention, a thermal CVD method can be applied.
Hereinafter, the configuration of this embodiment will be described with reference to FIG.
【００３４】まず、図１（ａ）に示すように、単結晶シ
リコン基板１０１上にＴｉ、ＴｉＮ、Ｒｕ膜からなる下
部電極層１０２を化学気相成長法（ＣＶＤ法）或いはス
パッタ法により順次形成する。この実施形態において
は、熱ＣＶＤ法を用い、Ｏ2ガスを供給しつつ第１の高
誘電率酸化膜層を形成する処理を行い、第２の高誘電率
酸化膜層の形成は、酸化力の高いＮ2Ｏガスを用いて行
うものである。First, as shown in FIG. 1A, a lower electrode layer 102 made of a Ti, TiN, or Ru film is sequentially formed on a single crystal silicon substrate 101 by a chemical vapor deposition method (CVD method) or a sputtering method. I do. In this embodiment, a process of forming a first high dielectric constant oxide film layer is performed by using a thermal CVD method while supplying O 2 gas, and the second high dielectric constant oxide film layer is formed by an oxidizing power. This is performed using N 2 O gas having a high density.
【００３５】この実施形態においては、第１の酸化膜形
成処理として、熱ＣＶＤ法を用い、酸素源としてＯ2／
Ａｒ＝１／１ガスを供給し、図１（ｂ）に示すように第
１の高誘電率酸化膜層１０３である（ＢＡ，Ｓｒ）Ｔｉ
Ｏ3膜を１５秒間形成した。In this embodiment, thermal CVD is used as the first oxide film forming process, and O 2 /
Ar = 1/1 gas is supplied, and as shown in FIG. 1B, (BA, Sr) Ti which is the first high-dielectric-constant oxide film layer 103 is formed.
An O 3 film was formed for 15 seconds.
【００３６】そして、第２の酸化膜形成処理として、熱
ＣＶＤ法を用い、酸素源としてＮ2Ｏ／Ａｒ＝１／１ガ
スを供給し、第１の高誘電率酸化膜層の成膜後、大気暴
露することなく、図１（Ｃ）に示すように第２の高誘電
率酸化膜層１０４である（ＢＡ，Ｓｒ）ＴｉＯ3膜を所
望の膜厚まで形成した。最後に図１（ｄ）に示すよう
に、上部電極層１０５であるＲｕ膜を化学気相成長法
（ＣＶＤ法）或いはスパッタ法により形成して、図示の
積層構造の薄膜キャパシタを得た。Then, as a second oxide film forming process, a thermal CVD method is used, N 2 O / Ar = 1/1 gas is supplied as an oxygen source, and after the first high dielectric constant oxide film layer is formed. Then, without exposure to the air, a (BA, Sr) TiO 3 film as the second high dielectric constant oxide film layer 104 was formed to a desired thickness as shown in FIG. Finally, as shown in FIG. 1D, a Ru film serving as the upper electrode layer 105 was formed by a chemical vapor deposition method (CVD method) or a sputtering method to obtain a thin film capacitor having a laminated structure as shown.
【００３７】図３は、この実施形態２によって得られた
薄膜キャパシタ（実施例２）と、酸素源としてＮ2Ｏ／
Ａｒ＝１／１ガスのみで形成する従来法で形成した薄膜
キャパシタ（従来例２）との電流−電圧特性を比較した
図である。FIG. 3 shows a thin film capacitor obtained in the second embodiment (Example 2) and N 2 O /
FIG. 9 is a diagram comparing current-voltage characteristics with a thin film capacitor formed by a conventional method (conventional example 2) formed only with Ar = 1/1 gas.
【００３８】従来例２による薄膜キャパシタによれば、
駆動電圧が１Ｖ以下においてもリーク電流密度が大き
く、このため、デバイス動作上問題があるのに対し、実
施例２による薄膜キャパシタは、実施例１と同様に印加
される駆動電圧が１，５Ｖにおいてもリーク電流密度が
１×１０-8Ａ／ｃｍ2以下の良好なリーク特性が得ら
れ、リーク特性の大幅な改善効果が見られた。According to the thin film capacitor according to Conventional Example 2,
Even when the driving voltage is 1 V or less, the leakage current density is large, which causes a problem in device operation. On the other hand, the thin film capacitor according to the second embodiment has a driving voltage of 1.5 V as in the first embodiment. Also, good leak characteristics having a leak current density of 1 × 10 −8 A / cm 2 or less were obtained, and a significant effect of improving the leak characteristics was observed.
【００３９】本実施形態２によれば、第１の高誘電率絶
縁膜層１０３を酸化力の低いＯ2／Ａｒ＝１／１ガスの
供給のみで形成する処理を行っているので、酸化力の強
いＮ 2Ｏ／Ａｒ＝１／１ガスにより、Ｒｕ下部電極の表
面酸化による荒れが抑制され、薄膜キャパシタは良好な
リーク特性を示すという利点が得られる。According to the second embodiment, the first high dielectric constant
The edge layer 103 is made of O having a low oxidizing power.Two/ Ar = 1/1 gas
Because of the process of forming only by supply, strong oxidizing power
I N TwoO / Ar = 1/1 gas allows Ru lower electrode surface
Roughness due to surface oxidation is suppressed, and thin film capacitors
The advantage of exhibiting a leak characteristic is obtained.
【００４０】上記の実施形態においては、第１の高誘電
率絶縁膜層１０３の形成を１５秒間で行なったが、第１
の実施形態と同様に、第１の高誘電率絶縁膜層１０３の
形成時間は、１〜１５秒程度の範囲内で短時間の方が望
ましい。In the above embodiment, the formation of the first high dielectric constant insulating film layer 103 was performed in 15 seconds.
Similarly to the above embodiment, it is preferable that the formation time of the first high-dielectric-constant insulating film layer 103 is short within a range of about 1 to 15 seconds.
【００４１】以上のように、本発明においては、酸化力
を下げた雰囲気中で第１の高誘電率絶縁膜層形成するこ
とにより、白金族元素材料を用いた下部電極表面の酸化
による荒れが抑制され、ついで、酸化力を上げた雰囲気
中で第２の高誘電率酸化膜層を形成することにより、第
１の高誘電率絶縁膜層の酸素欠損が補填され、酸素欠損
によるリーク特性不良は生じない。As described above, in the present invention, by forming the first high dielectric constant insulating film layer in an atmosphere having reduced oxidizing power, roughness of the lower electrode surface using a platinum group element material due to oxidation is reduced. Then, the second high-dielectric-constant oxide film layer is formed in an atmosphere having an increased oxidizing power to compensate for oxygen vacancies in the first high-dielectric-constant insulating film layer and to cause a leak characteristic defect due to the oxygen deficiency. Does not occur.
【００４２】また、上記２つの実施形態においては、下
部電極層としてＴｉ、ＴｉＮ、Ｒｕの積層構造について
述べたが、下部電極最表面層がＲｕ及びＩｒのような白
金族元素で形成されていれば、同様の効果が得られる。In the above two embodiments, the laminated structure of Ti, TiN, and Ru has been described as the lower electrode layer. A similar effect can be obtained.
【００４３】また、上記２つの実施形態においては、高
誘電率酸化膜に（Ｂａ，Ｓｒ）ＴｉＯ3を用いた例を述
べたが、本発明は、高誘電率酸化膜層が化学式ＡＢＯ3
で表され、それぞれＡとしてＢａ、Ｓｒ、Ｐｂ、Ｃａ、
Ｌａ、Ｌｉ、Ｋのうち少なくても１種類以上、Ｂとして
Ｔｉ、Ｚｒ、Ｔａ、Ｎｂ、Ｍｇ、Ｆｅ、Ｚｎ、Ｗのうち
少なくても１種類以上を含むものであればよい。Further, in the above two embodiments, an example in which (Ba, Sr) TiO 3 is used for the high dielectric constant oxide film has been described. However, in the present invention, the high dielectric constant oxide film layer has the chemical formula ABO 3
Where A is Ba, Sr, Pb, Ca,
What is necessary is just to include at least one or more of La, Li, and K and B as at least one or more of Ti, Zr, Ta, Nb, Mg, Fe, Zn, and W.
【００４４】例えばＳｒＴｉＯ3、（Ｓｒ，Ｃａ）Ｔｉ
Ｏ3、（Ｂａ，Ｓｒ，Ｃａ）ＴｉＯ3、ＰｂＴｉＯ3、Ｐ
ｂ（Ｚｒ，Ｔｉ）Ｏ3、（Ｐｂ，Ｌａ）（Ｚｒ，Ｔｉ）
Ｏ3、Ｐｂ（Ｍｇ，Ｎｂ）Ｏ3、Ｐｂ（Ｍｇ，Ｗ）Ｏ3、
Ｐｂ（Ｚｎ，Ｎｂ）Ｏ3ＬｉＴａＯ3、ＬｉＮｂＯ3、Ｋ
ＴａＯ3、ＫＮｂＯ3など、或は化学式（Ｂｉ2Ｏ2）（Ａ
ｍ-１ＢｍＯ3ｍ＋１）（ｍ＝１，２，３，４，５）で表
され、それぞれＡとしてＢａ、Ｓｒ、Ｐｂ、Ｃａ、Ｋ、
Ｂｉのうち１種類以上、ＢとしてＮｂ、Ｔａ、Ｔｉ、Ｗ
の少なくとも１種類以上を含むもの、例えばＢｉ4Ｔｉ3
Ｏ12、ＳｒＢｉ2Ｔａ2Ｏ9、ＳｒＢｉ2Ｎｂ2Ｏ9、或は上
記化学式とは異なる化学組成をもつＴａ2Ｏ 5についても
同様の効果が得られる。For example, SrTiOThree, (Sr, Ca) Ti
OThree, (Ba, Sr, Ca) TiOThree, PbTiOThree, P
b (Zr, Ti) OThree, (Pb, La) (Zr, Ti)
OThree, Pb (Mg, Nb) OThree, Pb (Mg, W) OThree,
Pb (Zn, Nb) OThreeLiTaOThree, LiNbOThree, K
TaOThree, KNbOThreeOr the chemical formula (BiTwoOTwo) (A
m-1BmOThreem + 1) (m = 1, 2, 3, 4, 5)
And A, Ba, Sr, Pb, Ca, K,
One or more of Bi, B is Nb, Ta, Ti, W
Including at least one or more of, for example, BiFourTiThree
O12, SrBiTwoTaTwoO9, SrBiTwoNbTwoO9Or above
Ta having a chemical composition different from the above chemical formulaTwoO FiveAbout
Similar effects can be obtained.
【００４５】また、以上の実施形態では（Ｂａ，Ｓｒ）
ＴｉＯ3が２層構造について述べたが、第１の高誘電率
酸化膜層が形成されていれば、上層である第２の高誘電
率酸化膜層は、複数の層の積層で構成されている場合に
も同様の効果が得られる。In the above embodiment, (Ba, Sr)
Although TiO 3 has been described as having a two-layer structure, if the first high-dielectric-constant oxide film layer is formed, the second high-dielectric-constant oxide film layer, which is an upper layer, is formed by laminating a plurality of layers. The same effect can be obtained even if there is.
【００４６】[0046]
【発明の効果】以上のように、本発明によるときには、
酸化力の下げた雰囲気中で第１の高誘電率絶縁膜層を形
成することにより、下部電極材料であるＲｕ及びＩｒ表
面の酸化による荒れを抑制することが可能となる。As described above, according to the present invention,
By forming the first high-dielectric-constant insulating film layer in an atmosphere having reduced oxidizing power, it is possible to suppress roughness of Ru and Ir surfaces, which are lower electrode materials, due to oxidation.
【００４７】また酸化力を上げた雰囲気中で第２の高誘
電率酸化膜層を形成することにより、第１の高誘電率絶
縁膜層の酸素欠損が補填され、酸素欠損によるリーク特
性不良は生じない。また本発明によれば、複数層からな
る高誘電率酸化膜の形成をＣＶＤ装置内で連続して行な
うことができる効果を有する。Further, by forming the second high dielectric constant oxide film layer in an atmosphere having an increased oxidizing power, oxygen deficiencies in the first high dielectric constant insulating film layer are compensated for, and leak characteristics failure due to oxygen vacancies is reduced. Does not occur. Further, according to the present invention, there is an effect that the formation of a high-dielectric-constant oxide film having a plurality of layers can be continuously performed in a CVD apparatus.
【図１】（ａ）〜（ｄ）は、本発明による薄膜キャパシ
タの製造方法を製造工程順に示すである。1A to 1D show a method of manufacturing a thin film capacitor according to the present invention in the order of manufacturing steps.
【図２】実施例１の薄膜キャパシタと、従来例１の薄膜
キャパシタとの電流−電圧特性を比較した図である。FIG. 2 is a diagram comparing the current-voltage characteristics of the thin film capacitor of Example 1 and the thin film capacitor of Conventional Example 1;
【図３】実施例２の薄膜キャパシタと、従来例２の薄膜
キャパシタとの電流−電圧特性を比較した図である。FIG. 3 is a diagram comparing current-voltage characteristics of a thin film capacitor of Example 2 and a thin film capacitor of Conventional Example 2;
【図４】従来法によって得られたキャパシタのリーク特
性を示す図である。FIG. 4 is a diagram showing a leakage characteristic of a capacitor obtained by a conventional method.
１０１ シリコン基板 １０２ 下部電極層 １０３ 第１の高誘電率絶縁膜層 １０４ 第２の高誘電率絶縁膜層 １０５ 上部電極層 Reference Signs List 101 silicon substrate 102 lower electrode layer 103 first high dielectric constant insulating film layer 104 second high dielectric constant insulating film layer 105 upper electrode layer
Claims (7)
形成処理とを有し、相対的に酸化力を変化させて白金族
元素からなる下部電極層上に高誘電率酸化膜層キャパシ
タを形成する薄膜キャパシタの製造方法であって、 第１の酸化膜形成処理は、酸化力を下げた雰囲気中で下
部電極層上に第１の高誘電率酸化膜層を形成する処理で
あり、 第２の酸化膜形成処理は、酸化力を上げた雰囲気中で、
第１の高誘電率酸化膜層上に、第２の高誘電率酸化膜層
を形成する処理であり、次いで第２の高誘電率酸化膜層
上に、上部電極層を形成することを特徴とする薄膜キャ
パシタの製造方法。A first oxide film forming process and a second oxide film forming process, wherein a high dielectric constant oxide film is formed on a lower electrode layer made of a platinum group element by relatively changing oxidizing power. A method for manufacturing a thin film capacitor for forming a layer capacitor, wherein a first oxide film forming process is a process of forming a first high dielectric constant oxide film layer on a lower electrode layer in an atmosphere having reduced oxidizing power. Yes, the second oxide film forming process is performed in an atmosphere having an increased oxidizing power.
Forming a second high dielectric constant oxide film layer on the first high dielectric oxide film layer, and then forming an upper electrode layer on the second high dielectric constant oxide film layer. Of manufacturing a thin film capacitor.
た雰囲気中で第１の高誘電率絶縁膜層を形成して、下部
電極材料表面の酸化による荒れ抑制する処理であり、 第２の酸化膜形成処理は、酸化力を上げた雰囲気中で第
２の高誘電率酸化膜層を形成して第１の高誘電率絶縁膜
層の酸素欠損を補填する処理であることを特徴とする請
求項１に記載の薄膜キャパシタの製造方法。2. The first oxide film forming process is a process of forming a first high-dielectric-constant insulating film layer in an atmosphere having reduced oxidizing power and suppressing roughness of the surface of the lower electrode material due to oxidation. The second oxide film forming process is a process for forming a second high dielectric constant oxide film layer in an atmosphere having an increased oxidizing power to compensate for oxygen vacancies in the first high dielectric constant insulating film layer. The method for manufacturing a thin film capacitor according to claim 1, wherein:
の製造方法であって、 第１の酸化膜形成処理は、Ｏ2プラズマを未照射状態で
第１の高誘電率酸化膜層を形成する処理であり、 第２の酸化膜形成処理は、Ｏ2プラズマ照射状態で第２
の高誘電率酸化膜層を形成する処理であることを特徴と
する請求項１に記載の薄膜キャパシタの製造方法。3. A method for manufacturing a thin film capacitor using ECR-CVD, wherein the first oxide film forming process is a process for forming a first high dielectric constant oxide film layer in a state where O 2 plasma is not irradiated. There, the second oxide film forming process, first in an O 2 plasma irradiation state 2
2. The method for manufacturing a thin film capacitor according to claim 1, wherein the high dielectric constant oxide film layer is formed.
方法であって、 第１の酸化膜形成処理は、Ｏ2ガスを用いて第１の高誘
電率酸化膜層を形成する処理であり、 第２の酸化膜形成処理は、酸化力の高いＮ2Ｏガスを用
いて第２の高誘電率酸化膜層を形成する処理であること
を特徴とする請求項１に記載の薄膜キャパシタの製造方
法。4. A method of manufacturing a thin film capacitor using thermal CVD, wherein the first oxide film forming process is a process of forming a first high dielectric constant oxide film layer using O 2 gas. 2. The method for manufacturing a thin film capacitor according to claim 1, wherein the second oxide film forming process is a process of forming a second high dielectric constant oxide film layer using N 2 O gas having high oxidizing power. .
電率酸化膜の成膜後、大気に暴露することなく、所望の
膜厚まで形成する処理であることを特徴とする請求項３
または４に記載の薄膜キャパシタの製造方法。5. The method according to claim 1, wherein the second high-dielectric-constant oxide film layer is a process for forming the first high-dielectric-constant oxide film to a desired film thickness without exposing it to the air after forming the first high-dielectric-constant oxide film. Claim 3
Or the method of manufacturing a thin film capacitor according to 4.
１〜１５秒の範囲であることを特徴とする請求項３また
は４に記載の薄膜キャパシタの製造方法。6. The formation time of the first high dielectric constant insulating film layer is as follows:
5. The method according to claim 3, wherein the time is in the range of 1 to 15 seconds.
積層であることを特徴とする請求項１に記載の薄膜キャ
パシタの製造方法。7. The method according to claim 1, wherein the second high-dielectric-constant oxide film layer is a laminate of a plurality of layers.
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|---|---|---|---|
| JP11112589A JP2000307077A (en) | 1999-04-20 | 1999-04-20 | Manufacture of thin film capacitor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11112589A JP2000307077A (en) | 1999-04-20 | 1999-04-20 | Manufacture of thin film capacitor |
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|---|---|
| JP2000307077A true JP2000307077A (en) | 2000-11-02 |
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ID=14590533
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6790677B2 (en) | 2002-03-01 | 2004-09-14 | Fujitsu Limited | Method of forming a ferroelectric film and fabrication process of a semiconductor device having a ferroelectric film |
-
1999
- 1999-04-20 JP JP11112589A patent/JP2000307077A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6790677B2 (en) | 2002-03-01 | 2004-09-14 | Fujitsu Limited | Method of forming a ferroelectric film and fabrication process of a semiconductor device having a ferroelectric film |
| US6852551B2 (en) | 2002-03-01 | 2005-02-08 | Fujitsu Limited | Method of forming a ferroelectric film and fabrication process of a semiconductor device having a ferroelectric film |
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