JP3267278B2 - Method for manufacturing semiconductor device - Google Patents
Method for manufacturing semiconductor deviceInfo
- Publication number
- JP3267278B2 JP3267278B2 JP25597299A JP25597299A JP3267278B2 JP 3267278 B2 JP3267278 B2 JP 3267278B2 JP 25597299 A JP25597299 A JP 25597299A JP 25597299 A JP25597299 A JP 25597299A JP 3267278 B2 JP3267278 B2 JP 3267278B2
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- JP
- Japan
- Prior art keywords
- thin film
- ferroelectric
- lower electrode
- ferroelectric thin
- forming
- Prior art date
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、主に不揮発性メモ
リ装置に使用される強誘電体キャパシタを有する半導体
装置及びその製造方法に関し、特に鉛を１成分として含
む強誘電体キャパシタに注目する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a ferroelectric capacitor mainly used for a nonvolatile memory device and a method of manufacturing the same, and particularly focuses on a ferroelectric capacitor containing lead as one component.
【０００２】[0002]
【従来の技術】従来、例えばジャーナル・オブ・アプラ
イド・フィジックス（Ｊｏｕｒｎａｌｏｆ Ａｐｐｌｉ
ｅｄ Ｐｈｙｓｉｃｓ）第６４巻、１４８４項〜１４９
３項に記載されていた様に、強誘電体メモリ装置等に使
用される強誘電体キャパシタには、組成比が一様な前駆
体薄膜を形成した後アニールし、強誘電体薄膜を形成し
ていた。2. Description of the Related Art Conventionally, for example, Journal of Applied Physics (Journal of Appli Physics)
Physics) Vol. 64, pp. 1484-149
As described in item 3, in a ferroelectric capacitor used in a ferroelectric memory device or the like, a precursor thin film having a uniform composition ratio is formed and then annealed to form a ferroelectric thin film. I was
【０００３】図２の断面構造図を基に従来例を説明す
る。A conventional example will be described with reference to the sectional structural view of FIG.
【０００４】すなわち、シリコン基板１０１上に下部電
極１０３を形成し、下部電極１０３上に酸化鉛を過剰に
含む、一様な組成比を持つ強誘電体薄膜の前駆体である
ＰＺＴ２００をスパッタ法により形成した後、ペロブス
カイト構造の強誘電相を得るため、５００℃から９００
℃の温度でアニールしていた。That is, a lower electrode 103 is formed on a silicon substrate 101, and PZT200, which is a precursor of a ferroelectric thin film having a uniform composition ratio and containing excess lead oxide, is formed on the lower electrode 103 by sputtering. After the formation, to obtain a ferroelectric phase having a perovskite structure, the temperature is increased from 500 ° C. to 900 ° C.
Annealed at a temperature of ° C.
【０００５】その後上部電極１１０を形成していた。After that, an upper electrode 110 was formed.
【０００６】この様に、スパッタ法に於て、強誘電体薄
膜を得るには、強誘電体の前駆体薄膜を形成した後に後
処理として５００℃から９００℃程度の温度で、酸素雰
囲気中で１時間程度アニールを行い完全な強誘電相、す
なわちペロブスカイト構造を得ていた。As described above, in order to obtain a ferroelectric thin film by sputtering, after forming a ferroelectric precursor thin film, post-processing is performed at a temperature of about 500 ° C. to 900 ° C. in an oxygen atmosphere. Annealing was performed for about one hour to obtain a complete ferroelectric phase, that is, a perovskite structure.
【０００７】また、従来ゾル−ゲル法に於いてもＰＺＴ
を形成する場合、Ｐｂ、チタン（Ｔｉ）、ジルコニウム
（Ｚｒ）の金属アルコキシドを化学量論組成のモル比で
均一溶液とし、これを下部電極上に塗布し、その後、７
００℃で焼成してはじめて強誘電相を得ることが出来
る。[0007] In the conventional sol-gel method, PZT
Is formed, a metal alkoxide of Pb, titanium (Ti), and zirconium (Zr) is made into a uniform solution in a molar ratio of the stoichiometric composition, and the solution is applied on the lower electrode.
A ferroelectric phase can be obtained only after firing at 00 ° C.
【０００８】[0008]
【発明が解決しようとする課題】しかし、従来Ｐｂを１
成分として含む強誘電体薄膜を形成する場合、この様に
して下部電極上に形成された強誘電体の前駆体薄膜は、
アニール時に蒸気圧の高いＰｂが前駆体薄膜表面から蒸
発し、強誘電体薄膜の厚さ方向にＰｂの濃度分布が出来
てしまい、化学量論的組成に非常に近い一様な強誘電性
薄膜が有する特性に比べ、強誘電体薄膜の特性が著しく
劣化してしまうという問題点を有していた。However, the conventional Pb is 1
When forming a ferroelectric thin film containing as a component, the ferroelectric precursor thin film thus formed on the lower electrode,
During annealing, Pb with a high vapor pressure evaporates from the surface of the precursor thin film, resulting in a Pb concentration distribution in the thickness direction of the ferroelectric thin film, and a uniform ferroelectric thin film very close to the stoichiometric composition. However, there is a problem that the characteristics of the ferroelectric thin film are significantly deteriorated as compared with the characteristics of the ferroelectric thin film.
【０００９】そこで、本発明は従来のこの様な課題を解
決しようとするもので、その目的とするところは、アニ
ール後に於いて強誘電体薄膜の厚さ方向のＰｂ濃度分布
の変化を少なくし薄膜全体に於いて一様な組成、すなわ
ち化学量論的組成に非常に近い膜を形成し、強誘電体特
性の非常に良い膜を得る強誘電体薄膜の製造方法を提供
するところにある。Therefore, the present invention is to solve such a conventional problem, and an object of the present invention is to reduce the change in the Pb concentration distribution in the thickness direction of the ferroelectric thin film after annealing. It is an object of the present invention to provide a method for producing a ferroelectric thin film in which a film having a uniform composition in the whole thin film, that is, a film having a very close stoichiometric composition, is obtained to obtain a film having excellent ferroelectric characteristics.
【００１０】[0010]
【課題を解決するための手段】本発明の半導体装置の製
造方法は、 （１） 下部電極、上部電極、ならびに前記下部電極と
前記上部電極との間に鉛（Ｐｂ）が一成分として含まれ
る強誘電体薄膜を備えた強誘電体キャパシタを有する半
導体装置の製造方法であって、前記下部電極を形成する
工程と、前記下部電極上に前記強誘電体薄膜を高周波マ
グネトロンスパッタ法を用いて形成するスパッタ工程
と、前記強誘電体薄膜をアニールする工程と、前記上部
電極を形成する工程と、を有し、前記スパッタ工程が、
第一のガス圧力下で行われる第一のスパッタ工程と、前
記第一のガス圧力よりもガス圧の高い第二のガス圧力下
で行われる第二のスパッタ工程を備えることを特徴とす
る。 （２） 前記スパッタ工程では、前記第一のガス圧力か
ら前記第二のガス圧力まで、ガス圧力を連続的に増加さ
せて行われることを特徴とする。 （３） 下部電極、上部電極、ならびに前記下部電極と
前記上部電極との間に鉛（Ｐｂ）が一成分として含まれ
る強誘電体薄膜を備えた強誘電体キャパシタを有する半
導体装置の製造方法であって、前記下部電極を形成する
工程と、前記下部電極上に前記強誘電体薄膜を高周波マ
グネトロンスパッタ法を用いて形成するスパッタ工程
と、前記強誘電体薄膜をアニールする工程と、前記上部
電極を形成する工程と、を有し、前記スパッタ工程で
は、ガス圧力を一定に保ちながら、第一のＡｒ分圧か
ら、該第一のＡｒ分圧より高い第二のＡｒ分圧へＡｒ分
圧を増加させてデポジションが行われることを特徴とす
る。 （４） 下部電極、上部電極、ならびに前記下部電極と
前記上部電極との間に鉛（Ｐｂ）が一成分として含まれ
る強誘電体薄膜を備えた強誘電体キャパシタを有する半
導体装置の製造方法であって、前記下部電極を形成する
工程と、前記下部電極上に前記強誘電体薄膜を高周波マ
グネトロンスパッタ法を用いて形成するスパッタ工程
と、前記強誘電体薄膜をアニールする工程と、前記上部
電極を形成する工程と、を有し、前記スパッタ工程で
は、ターゲットと基板との距離を増加させながらデポジ
ションが行われることを特徴とする。 （５） 下部電極、上部電極、ならびに前記下部電極と
前記上部電極との間に鉛（Ｐｂ）が一成分として含まれ
る強誘電体薄膜を備えた強誘電体キャパシタを有する半
導体装置の製造方法であって、前記下部電極を形成する
工程と、前記下部電極上に、前記強誘電体薄膜の前駆体
材料を塗布する工程と、該前駆体材料を熱処理する工程
と、前記上部電極を形成する工程とを有し、前記下部電
極の形成後において、前記強誘電体薄膜の前駆体材料を
塗布する工程と該前駆体材料を熱処理する工程が複数回
繰り返し行われ、且つ、前記前駆体材料中の鉛の濃度が
前記下部電極側と比べて前記上部電極側で増加するよう
に形成することを特徴とする。According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: (1) a lower electrode, an upper electrode, and one component of lead (Pb) between the lower electrode and the upper electrode. A method of manufacturing a semiconductor device having a ferroelectric capacitor having a ferroelectric thin film, comprising: forming the lower electrode; and forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method. And a step of annealing the ferroelectric thin film, and a step of forming the upper electrode, wherein the sputtering step
It is characterized by comprising a first sputtering step performed under a first gas pressure and a second sputtering step performed under a second gas pressure having a gas pressure higher than the first gas pressure. (2) The sputtering is performed by continuously increasing the gas pressure from the first gas pressure to the second gas pressure. (3) A method of manufacturing a semiconductor device including a lower electrode, an upper electrode, and a ferroelectric capacitor including a ferroelectric thin film containing lead (Pb) as one component between the lower electrode and the upper electrode. A step of forming the lower electrode; a step of forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method; a step of annealing the ferroelectric thin film; And forming a partial pressure in the sputtering step from the first Ar partial pressure to a second Ar partial pressure higher than the first Ar partial pressure while keeping the gas pressure constant. Is increased, and the deposition is performed. (4) A method of manufacturing a semiconductor device including a lower electrode, an upper electrode, and a ferroelectric capacitor including a ferroelectric thin film containing lead (Pb) as one component between the lower electrode and the upper electrode. A step of forming the lower electrode; a step of forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method; a step of annealing the ferroelectric thin film; And depositing while increasing the distance between the target and the substrate in the sputtering step. (5) Lead (Pb) is contained as one component between the lower electrode, the upper electrode, and the lower electrode and the upper electrode.
A method of manufacturing a semiconductor device having a ferroelectric capacitor provided with a ferroelectric thin film, comprising: forming the lower electrode; and applying a precursor material of the ferroelectric thin film on the lower electrode. And a step of heat-treating the precursor material; and a step of forming the upper electrode. After forming the lower electrode, a step of applying a precursor material for the ferroelectric thin film and the precursor The step of heat-treating the material is repeated a plurality of times, and the concentration of lead in the precursor material is reduced.
As it increases on the upper electrode side compared to the lower electrode side
Is formed .
【００１１】[0011]
【００１２】[0012]
【００１３】[0013]
【００１４】[0014]
【実施例】本発明の強誘電体薄膜の製造方法の第１の実
施例を図１（ａ）〜（ｅ）の製造工程断面図に基づき説
明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a method of manufacturing a ferroelectric thin film according to the present invention will be described with reference to FIGS.
【００１５】ここでは簡単のため、強誘電体特性を調べ
るための試料の製造方法について述べることにする。Here, for simplicity, a method of manufacturing a sample for examining ferroelectric characteristics will be described.
【００１６】勿論この製造方法を半導体装置にそのまま
応用すれば、強誘電体を用いた半導体メモリ装置を作る
ことが出来る。Of course, if this manufacturing method is applied to a semiconductor device as it is, a semiconductor memory device using a ferroelectric can be manufactured.
【００１７】第１の実施例では、強誘電体薄膜の製造方
法としてゾル−ゲル法を用いた。In the first embodiment, a sol-gel method was used as a method for producing a ferroelectric thin film.
【００１８】まず、図１（ａ）のように、ｎ型シリコン
基板１０１上に、化学的気相成長法により約５０００Å
の二酸化珪素膜１０２を、更にスパッタ法により約２０
００Åの白金（Ｐｔ）を下部電極１０３として順次形成
する。First, as shown in FIG. 1A, about 5000 ° C. is formed on an n-type silicon substrate 101 by a chemical vapor deposition method.
Silicon dioxide film 102 is further
Platinum (Pt) of 00 ° is sequentially formed as the lower electrode 103.
【００１９】次に、図１（ｂ）のように、５００Åの第
１の強誘電体前駆体薄膜１０４を塗布する。この強誘電
体前駆体薄膜１０４は、Ｐｂ、Ｚｒ、Ｔｉの金属アルコ
キシドを１．００：０．５２：０．４８のモル比で均一
溶液としたものである。Next, as shown in FIG. 1B, a first ferroelectric precursor thin film 104 of 500 ° is applied. This ferroelectric precursor thin film 104 is a uniform solution of metal alkoxides of Pb, Zr and Ti at a molar ratio of 1.00: 0.52: 0.48.
【００２０】この強誘電体前駆体薄膜１０４を下部電極
１０３上に塗布した後、酸素雰囲気中、２００℃で２０
分の仮焼成を行う。After this ferroelectric precursor thin film 104 is applied on the lower electrode 103, the thin film is heated at 200 ° C. in an oxygen atmosphere.
For a minute.
【００２１】その後、図１（ｃ）に示すようにそれぞれ
５００Åの第２から第６の強誘電体前駆体薄膜１０５、
１０６、１０７、１０８、１０９を同様にして形成す
る。Thereafter, as shown in FIG. 1 (c), the second to sixth ferroelectric precursor thin films 105
106, 107, 108, and 109 are formed in the same manner.
【００２２】但し第２から第６の強誘電体前駆体薄膜１
０５、１０６、１０７、１０８、１０９はＰｂ、Ｚｒ、
Ｔｉの金属アルコキシドを下記に示すモル比で均一溶液
としたものである。However, the second to sixth ferroelectric precursor thin films 1
05, 106, 107, 108 and 109 are Pb, Zr,
It is a uniform solution of Ti metal alkoxide in the following molar ratio.
【００２３】Pb : Zr : Ti 第2の強誘電体前駆体薄膜105 1.01:0.52:0.48 第3の強誘電体前駆体薄膜106 1.02:0.52:0.48 第4の強誘電体前駆体薄膜１０７ １．０３：０．５
２：０．４８ 第５の強誘電体前駆体薄膜108 1.04:0.52:0.48 第6の強誘電体前駆体薄膜109 1.05:0.52:0.48 すなわち、どんどん強誘電体前駆体薄膜が積み重なるに
つれ、Ｐｂ濃度を増加するようにした。Pb: Zr: Ti Second ferroelectric precursor thin film 105 1.01: 0.52: 0.48 Third ferroelectric precursor thin film 106 1.02: 0.52: 0.48 Fourth ferroelectric precursor thin film 107 03: 0.5
2: 0.48 Fifth ferroelectric precursor thin film 108 1.04: 0.52: 0.48 Sixth ferroelectric precursor thin film 109 1.05: 0.52: 0.48 That is, as the ferroelectric precursor thin films accumulate, the Pb concentration increases. Was increased.
【００２４】第６の強誘電体前駆体薄膜１０９形成後に
も仮焼成を行なった。Preliminary firing was also performed after the formation of the sixth ferroelectric precursor thin film 109.
【００２５】その後、酸素雰囲気中、７００℃で焼成を
１時間行うことにより、ＰＺＴの多結晶薄膜を形成する
ことが出来た。After that, baking was performed at 700 ° C. for 1 hour in an oxygen atmosphere, thereby forming a polycrystalline thin film of PZT.
【００２６】次に図１（ｄ）に示すように、上部電極１
１０として厚さ１０００ÅのＰｔをスパッタ法で形成し
た後、図１（ｅ）の様に、普通のフォトリソグラフィー
を用いて上部電極１１０のＰｔを１００μｍ角にパター
ニングした。Next, as shown in FIG.
After forming Pt with a thickness of 1000 ° by sputtering as 10, as shown in FIG. 1E, the Pt of the upper electrode 110 was patterned into a 100 μm square by using ordinary photolithography.
【００２７】図３に７００℃での焼成を行った前後のＰ
ｂ濃度の深さプロファイルを示す。FIG. 3 shows P before and after firing at 700 ° C.
4 shows a depth profile of b concentration.
【００２８】このように焼成後のＰｂ濃度の深さ分布
は、ほぼ一様となり化学量論的組成に非常に近いもので
あった。As described above, the depth distribution of the Pb concentration after firing was almost uniform and was very close to the stoichiometric composition.
【００２９】図４に示すように、この強誘電体薄膜の強
誘電体特性はソーヤ・タワー回路によるヒステリシスカ
ーブで測定された。測定は室温、５０Ｈｚの周波数で行
った。As shown in FIG. 4, the ferroelectric characteristics of this ferroelectric thin film were measured by a hysteresis curve using a Sawyer tower circuit. The measurement was performed at room temperature at a frequency of 50 Hz.
【００３０】残留分極３０μＣ／ｃｍ2、抗電界３０ｋ
Ｖ／ｃｍと良好な強誘電性特性が 得られた。Residual polarization 30 μC / cm 2 , coercive electric field 30 k
Good ferroelectric properties of V / cm were obtained.
【００３１】第１の実施例では、強誘電体前駆体薄膜の
塗布を６回行ったが、２回としてもよい。In the first embodiment, the ferroelectric precursor thin film is applied six times, but may be applied twice.
【００３２】その時は、１回目に塗布する強誘電体前駆
体薄膜のＰｂモル比に比べて２回目に塗布する強誘電体
前駆体薄膜のＰｂモル比を上げてやればよい。At this time, the Pb molar ratio of the ferroelectric precursor thin film applied second time may be increased as compared with the Pb molar ratio of the ferroelectric precursor thin film applied first.
【００３３】本発明の強誘電体薄膜の製造方法の第２の
実施例を図５（ａ）〜（ｄ）の製造工程断面図に基づき
説明する。A second embodiment of the method for producing a ferroelectric thin film according to the present invention will be described with reference to the sectional views of the production steps shown in FIGS.
【００３４】第２の実施例では、強誘電体薄膜の製造方
法として高周波マグネトロンスパッタ法を用いた。In the second embodiment, a high-frequency magnetron sputtering method was used as a method for manufacturing a ferroelectric thin film.
【００３５】まず、図５（ａ）のように、第１の実施例
と同様にして、シリコン基板１０１上に二酸化珪素膜１
０２、下部電極１０３を形成する。First, as shown in FIG. 5A, a silicon dioxide film 1 is formed on a silicon substrate 101 in the same manner as in the first embodiment.
02, the lower electrode 103 is formed.
【００３６】次に、図５（ｂ）のように、２５００Åの
第１の強誘電体薄膜５０４を高周波マグネトロンスパッ
タ法により形成する。Next, as shown in FIG. 5B, a first ferroelectric thin film 504 of 2500 ° is formed by a high-frequency magnetron sputtering method.
【００３７】この時ターゲットにＰｂ1.1Ｚｒ0.5Ｔｉ
0.5Ｏ3を用いた。At this time, the target was Pb 1.1 Zr 0.5 Ti
0.5 O 3 was used.
【００３８】基板温度３００℃、Ａｒ：Ｏ2＝９：１の
雰囲気ガスとし、２０ｍＴｏｒｒ、パワー３００Ｗとし
た。The substrate temperature was 300 ° C., the atmosphere gas was Ar: O 2 = 9: 1, the pressure was 20 mTorr, and the power was 300 W.
【００３９】次に図５（ｃ）に示すように、ガス圧力だ
けを２５ｍＴｏｒｒに増加してイン・シチュでスパッタ
デポジションを行ない、５００Åの第２の強誘電体薄膜
５０５を形成した。Next, as shown in FIG. 5 (c), only the gas pressure was increased to 25 mTorr, and a sputter deposition was performed in situ to form a second ferroelectric thin film 505 of 500 °.
【００４０】同じターゲットを用いても雰囲気ガスの圧
力だけを変化させることにより、デポジションされた薄
膜の組成比を変化させることは可能である。Even when the same target is used, it is possible to change the composition ratio of the deposited thin film by changing only the pressure of the atmospheric gas.
【００４１】上に示した今のスパッタ条件に於いては、
圧力を増加させることによりＰｂ濃度を増加させること
が出来る。Under the current sputtering conditions shown above,
The Pb concentration can be increased by increasing the pressure.
【００４２】スパッタ直後の強誘電体薄膜５０４、５０
５は完全な強誘電相すなわちペロブスカイト構造を示さ
ない。Ferroelectric thin films 504 and 50 immediately after sputtering
No. 5 does not show a perfect ferroelectric phase, that is, a perovskite structure.
【００４３】すなわち、ペロブスカイト構造と強誘電相
を示さないパイロクロア相の混合状態となっている。That is, a mixed state of a perovskite structure and a pyrochlore phase not exhibiting a ferroelectric phase is obtained.
【００４４】そこで、次に酸素雰囲気中、７５０℃で１
時間アニールを行い多結晶の完全な強誘電体相を形成す
る。Then, next, at 750.degree.
Perform time annealing to form a complete polycrystalline ferroelectric phase.
【００４５】最後に図５（ｄ）に示すように、第１の実
施例と同様にして、１００μｍ角のＰｔからなる上部電
極１１０を形成した。Finally, as shown in FIG. 5D, an upper electrode 110 of 100 μm square made of Pt was formed in the same manner as in the first embodiment.
【００４６】図６に７５０℃でのアニールを行った前後
のＰｂ濃度の深さプロファイルを示す。FIG. 6 shows a depth profile of the Pb concentration before and after annealing at 750 ° C.
【００４７】このようにアニール後のＰｂ濃度の深さ分
布は、ほぼ一様となり化学量論的組成に非常に近いもの
であった。As described above, the depth distribution of the Pb concentration after annealing was almost uniform and very close to the stoichiometric composition.
【００４８】又、ターゲットにＰｂ1.1Ｚｒ0.5Ｔｉ0.5
Ｏ3.1を用い、実施例２と同様の方法を用いて強誘電体
膜を製造した場合にもアニール後のＰｂの濃度の深さ分
布はほぼ一様となった。The target was Pb 1.1 Zr 0.5 Ti 0.5
Also in the case where a ferroelectric film was manufactured using O3.1 and using the same method as in Example 2, the depth distribution of the Pb concentration after annealing was almost uniform.
【００４９】この強誘電体薄膜の残留分極は５０μＣ／
ｃｍ2、抗電界は３５ｋＶ／ｃｍと良好な強誘電性特性
が得られた。The remanent polarization of this ferroelectric thin film is 50 μC /
cm 2 and a coercive electric field of 35 kV / cm, indicating good ferroelectric properties.
【００５０】第２の実施例では、スパッタ中にガス圧力
を２段階に分けてデポジションを行ったが、コンピュー
タ制御により、ガス圧力を連続的に増加させ、それにと
もなって強誘電体薄膜中のＰｂ濃度を徐々に、増加させ
ることも可能である。In the second embodiment, the deposition was performed by dividing the gas pressure into two stages during sputtering. However, the gas pressure was continuously increased by computer control, and accordingly, the deposition in the ferroelectric thin film was performed. It is also possible to gradually increase the Pb concentration.
【００５１】また、全ガス圧力を一定に保ちながら、Ａ
ｒ分圧を増加させることによっても強誘電体薄膜中のＰ
ｂ濃度を増加させることもできるし、ターゲットとシリ
コン基板の距離を増加させることによっても、強誘電体
薄膜中のＰｂ濃度を増加させることが可能である。Further, while keeping the total gas pressure constant, A
The partial pressure of P in the ferroelectric thin film can be increased by increasing the
The Pb concentration in the ferroelectric thin film can be increased by increasing the b concentration, or by increasing the distance between the target and the silicon substrate.
【００５２】第２の実施例において、アニールを行なっ
てから上部電極１１０を形成したが、上部電極１１０を
形成した後、アニールを行なってもよい。In the second embodiment, the upper electrode 110 is formed after annealing is performed. However, the annealing may be performed after the upper electrode 110 is formed.
【００５３】第１及び第２の実施例に於いて、シリコン
基板を用いたがマグネシア（ＭｇＯ）、サファイア等他
の基板を用いても良い。In the first and second embodiments, a silicon substrate is used, but another substrate such as magnesia (MgO) or sapphire may be used.
【００５４】また、強誘電体薄膜として、ＰＺＴすなわ
ちＰｂ（ＺｒXＴｉ1-X）Ｏ3、Ｘ＝０．４８、０．５を
用いて説明したが、他の組成比を持つＰＺＴであっても
よいし、ランタン（Ｌａ）をドーピングしたＰＬＺＴで
も勿論良いし、カルシウム（Ｃａ）、バリウム（Ｂ
ａ）、マグネシウム（Ｍｇ）、ナイオビウム（Ｎｂ）、
ストロンチウム（Ｓｒ）等がドーピングされていても勿
論良い。Further, PZT, that is, Pb (Zr x Ti 1 -x) O 3 , where X = 0.48 and 0.5 is used as the ferroelectric thin film, but PZT having another composition ratio is used. PLZT doped with lanthanum (La) may of course be used, and calcium (Ca), barium (B
a), magnesium (Mg), niobium (Nb),
Of course, strontium (Sr) or the like may be doped.
【００５５】[0055]
【発明の効果】本発明の強誘電体薄膜の製造方法は、以
上説明したように下部電極と上部電極の間に鉛（Ｐｂ）
を１成分として含む強誘電体薄膜が挟まれた構造を持つ
強誘電体薄膜の製造方法に於いて、前記下部電極上に前
記強誘電体の前駆体薄膜を前記下部電極側で鉛の濃度を
低濃度に、前記上部電極側で鉛の濃度を高濃度に形成す
ることによって、アニールを行い完全な強誘電相を得た
後のＰｂ組成比の上下方向のずれを極力無くす事によ
り、強誘電体特性の良好な薄膜を得ることが出来る効果
を有する。As described above, the method of manufacturing a ferroelectric thin film according to the present invention uses lead (Pb) between the lower electrode and the upper electrode.
In a method of manufacturing a ferroelectric thin film having a structure in which a ferroelectric thin film containing as one component is sandwiched, a precursor thin film of the ferroelectric is placed on the lower electrode, and a concentration of lead is reduced on the lower electrode side. By forming a high concentration of lead on the side of the upper electrode to a low concentration, annealing is performed to obtain a complete ferroelectric phase, thereby minimizing the vertical shift of the Pb composition ratio, thereby reducing ferroelectricity. This has the effect that a thin film having good body characteristics can be obtained.
【００５６】更に、この強誘電体薄膜の製造方法を用い
れば、不揮発性メモリや、光スイッチ、キャパシタ、赤
外線センサ、超音波センサ、薄膜圧電振動子として利用
できるといった効果を有する。Further, the use of the method for manufacturing a ferroelectric thin film has an effect that it can be used as a nonvolatile memory, an optical switch, a capacitor, an infrared sensor, an ultrasonic sensor, and a thin film piezoelectric vibrator.
【図１】本発明の強誘電体薄膜の製造方法の第１実施例
を示す製造工程断面図である。FIG. 1 is a sectional view showing a manufacturing process of a first embodiment of a method for manufacturing a ferroelectric thin film according to the present invention.
【図２】従来の強誘電体薄膜の製造方法を説明するため
の断面構造図である。FIG. 2 is a sectional structural view for explaining a conventional method for manufacturing a ferroelectric thin film.
【図３】本発明の第１実施例の強誘電体薄膜のＰｂ濃度
の表面からの深さ依存性を示すグラフである。FIG. 3 is a graph showing the dependence of the Pb concentration of the ferroelectric thin film of the first embodiment of the present invention on the depth from the surface.
【図４】本発明の第１実施例の強誘電体薄膜の強誘電体
特性を示す図である。FIG. 4 is a diagram showing ferroelectric characteristics of the ferroelectric thin film according to the first embodiment of the present invention.
【図５】本発明の強誘電体薄膜の製造方法の第２実施例
を示す製造工程断面図である。FIG. 5 is a sectional view of a manufacturing process showing a second embodiment of the method for manufacturing a ferroelectric thin film of the present invention.
【図６】本発明の第２実施例の強誘電体薄膜のＰｂ濃度
の表面からの深さ依存性を示すグラフである。FIG. 6 is a graph showing the dependence of the Pb concentration of the ferroelectric thin film of the second embodiment of the present invention on the depth from the surface.
１０１ シリコン基板 １０２ 二酸化珪素膜 １０３ 下部電極 １０４ 第１の強誘電体前駆体薄膜 １０５ 第２の強誘電体前駆体薄膜 １０６ 第３の強誘電体前駆体薄膜 １０７ 第４の強誘電体前駆体薄膜 １０８ 第５の強誘電体前駆体薄膜 １０９ 第６の強誘電体前駆体薄膜 １１０ 上部電極 ２００ ＰＺＴ ５０４ 第１の強誘電体薄膜 ５０５ 第２の強誘電体薄膜 Reference Signs List 101 silicon substrate 102 silicon dioxide film 103 lower electrode 104 first ferroelectric precursor thin film 105 second ferroelectric precursor thin film 106 third ferroelectric precursor thin film 107 fourth fourth ferroelectric precursor thin film 108 Fifth Ferroelectric Precursor Thin Film 109 Sixth Ferroelectric Precursor Thin Film 110 Upper Electrode 200 PZT 504 First Ferroelectric Thin Film 505 Second Ferroelectric Thin Film
Claims (5)
電極と前記上部電極との間に鉛（Ｐｂ）が一成分として
含まれる強誘電体薄膜を備えた強誘電体キャパシタを有
する半導体装置の製造方法であって、 前記下部電極を形成する工程と、 前記下部電極上に前記強誘電体薄膜を高周波マグネトロ
ンスパッタ法を用いて形成するスパッタ工程と、 前記強誘電体薄膜をアニールする工程と、 前記上部電極を形成する工程と、を有し、 前記スパッタ工程が、第一のガス圧力下で行われる第一
のスパッタ工程と、前記第一のガス圧力よりもガス圧の
高い第二のガス圧力下で行われる第二のスパッタ工程を
備えることを特徴とする半導体装置の製造方法。1. Manufacturing of a semiconductor device having a lower electrode, an upper electrode, and a ferroelectric capacitor including a ferroelectric thin film containing lead (Pb) as one component between the lower electrode and the upper electrode. A method of forming the lower electrode, a sputtering step of forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method, and a step of annealing the ferroelectric thin film; A step of forming an upper electrode, wherein the sputtering step is a first sputtering step performed under a first gas pressure, and a second gas pressure having a gas pressure higher than the first gas pressure. A method for manufacturing a semiconductor device, comprising: a second sputtering step performed below.
圧力から前記第二のガス圧力まで、ガス圧力を連続的に
増加させて行われることを特徴とする請求項１記載の半
導体装置の製造方法。2. The manufacturing of a semiconductor device according to claim 1, wherein the sputtering is performed by continuously increasing the gas pressure from the first gas pressure to the second gas pressure. Method.
電極と前記上部電極との間に鉛（Ｐｂ）が一成分として
含まれる強誘電体薄膜を備えた強誘電体キャパシタを有
する半導体装置の製造方法であって、 前記下部電極を形成する工程と、 前記下部電極上に前記強誘電体薄膜を高周波マグネトロ
ンスパッタ法を用いて形成するスパッタ工程と、 前記強誘電体薄膜をアニールする工程と、 前記上部電極を形成する工程と、を有し、 前記スパッタ工程では、ガス圧力を一定に保ちながら、 第一のＡｒ分圧から、該第一のＡｒ分圧より高い第二の
Ａｒ分圧へＡｒ分圧を増加させてデポジションが行われ
ることを特徴とする半導体装置の製造方法。3. Manufacturing of a semiconductor device having a lower electrode, an upper electrode, and a ferroelectric capacitor including a ferroelectric thin film containing lead (Pb) as one component between the lower electrode and the upper electrode. A method of forming the lower electrode, a sputtering step of forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method, and a step of annealing the ferroelectric thin film; Forming an upper electrode. In the sputtering step, the gas pressure is kept constant, and the Ar pressure is changed from the first Ar partial pressure to a second Ar partial pressure higher than the first Ar partial pressure. A method of manufacturing a semiconductor device, wherein deposition is performed by increasing a partial pressure.
電極と前記上部電極との間に鉛（Ｐｂ）が一成分として
含まれる強誘電体薄膜を備えた強誘電体キャパシタを有
する半導体装置の製造方法であって、 前記下部電極を形成する工程と、 前記下部電極上に前記強誘電体薄膜を高周波マグネトロ
ンスパッタ法を用いて形成するスパッタ工程と、 前記強誘電体薄膜をアニールする工程と、 前記上部電極を形成する工程と、を有し、 前記スパッタ工程では、ターゲットと基板との距離を増
加させながらデポジションが行われることを特徴とする
半導体装置の製造方法。4. Manufacture of a semiconductor device having a lower electrode, an upper electrode, and a ferroelectric capacitor including a ferroelectric thin film containing lead (Pb) as one component between the lower electrode and the upper electrode. A method of forming the lower electrode, a sputtering step of forming the ferroelectric thin film on the lower electrode by using a high-frequency magnetron sputtering method, and a step of annealing the ferroelectric thin film; Forming an upper electrode, wherein in the sputtering step, deposition is performed while increasing a distance between a target and a substrate.
電極と前記上部電極との間に鉛（Ｐｂ）が一成分として
含まれる強誘電体薄膜を備えた強誘電体キャパシタを有
する半導体装置の製造方法であって、 前記下部電極を形成する工程と、 前記下部電極上に、前記強誘電体薄膜の前駆体材料を塗
布する工程と、 該前駆体材料を熱処理する工程と、 前記上部電極を形成する工程とを有し、 前記下部電極の形成後において、前記強誘電体薄膜の前
駆体材料を塗布する工程と該前駆体材料を熱処理する工
程が複数回繰り返し行われ、且つ、前記前駆体材料中の鉛の濃度が前記下部電極側と
比べて前記上部電極側で増加するように形成すること を
特徴とする半導体装置の製造方法。5. A lower electrode, an upper electrode, and lead (Pb) as a component between the lower electrode and the upper electrode.
A method of manufacturing a semiconductor device having a ferroelectric capacitor provided with a ferroelectric thin film included therein , comprising: a step of forming the lower electrode; and coating a precursor material of the ferroelectric thin film on the lower electrode. A step of heat-treating the precursor material; and a step of forming the upper electrode. A step of applying the precursor material for the ferroelectric thin film after the formation of the lower electrode, and The step of heat-treating the body material is performed a plurality of times, and the concentration of lead in the precursor material is lower than that of the lower electrode.
A method of manufacturing a semiconductor device, wherein the semiconductor device is formed so as to increase on the upper electrode side .
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|---|---|---|---|
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24585591 | 1991-09-25 | ||
| JP3-245855 | 1991-09-25 | ||
| JP25597299A JP3267278B2 (en) | 1991-09-25 | 1999-09-09 | Method for manufacturing semiconductor device |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24090892A Division JP3182909B2 (en) | 1991-09-25 | 1992-09-09 | Method of manufacturing ferroelectric capacitor and method of manufacturing ferroelectric memory device |
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| JP2000082787A JP2000082787A (en) | 2000-03-21 |
| JP3267278B2 true JP3267278B2 (en) | 2002-03-18 |
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| CN108572488A (en) * | 2017-12-08 | 2018-09-25 | 北京航空航天大学 | A kind of photoswitch based on electrolysis screw type ferroelectric liquid crystals |
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| JP3944372B2 (en) * | 2001-09-21 | 2007-07-11 | 株式会社東芝 | Piezoelectric thin film vibrator and frequency variable resonator using the same |
| JP4663216B2 (en) * | 2003-06-10 | 2011-04-06 | ルネサスエレクトロニクス株式会社 | Semiconductor memory device and manufacturing method thereof |
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Cited By (2)
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| CN108572488A (en) * | 2017-12-08 | 2018-09-25 | 北京航空航天大学 | A kind of photoswitch based on electrolysis screw type ferroelectric liquid crystals |
| CN108572488B (en) * | 2017-12-08 | 2021-07-06 | 北京航空航天大学 | Optical switch based on electrolytic spiral ferroelectric liquid crystal |
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