JP3969206B2 - Production of PZT thin films by chemical vapor deposition - Google Patents

Description

【００１５】
溶媒量をできるだけ減らすには、Ｐｂ（ｄｐｍ）_２の溶解能の高い溶媒を使い、気化器圧力をできるだけ低くし、気化器温度をできるだけ高くすることが、望ましい。しかしＰｂ（ｄｐｍ）_２の低い蒸気圧と熱安定性を考慮すると、およそ２００〜２５０℃の範囲である。
【００１６】
Ｐｂ（ｄｐｍ）_２の飽和蒸気圧は、本発明者が気体飽和法により１３０〜１７０℃で測定した結果、次のクラウジウス−クラペイロン式で表される。
Ｌｏｇ_１０Ｐ＝−４４８０／Ｔ＋９．９４ Ｐ：Ｔｏｒｒ、Ｔ：Ｋ）
またＡｒ１気圧でのＰｂ（ｄｐｍ）_２の沸点をＴＧ−ＤＴＡで調べると３５０〜３５９℃であった。これは蒸気圧式の外挿から求めた値３６１℃と良く一致しているので、式の外挿は、信頼できる。そこでＰｂ（ｄｐｍ）_２の飽和蒸気圧を、上式から求めると、３．０Ｔｏｒｒ／２００℃、２４Ｔｏｒｒ／２５０℃となる。
【００１７】
気化器中の気体温度が完全に気化器温度になっていれば、２００℃の気化器圧力１０Ｔｏｒｒとした場合、（１０−３．０＝）７．０Ｔｏｒｒ分の溶媒があれば、原理上は全量が気体となりうる。すなわち最小必要溶媒量は、Ｐｂ（ｄｐｍ）_２の（７．０／３．０＝）２．４倍ｍｏｌ量である。表１の溶媒の分子量はＴＨＦの７２から酢酸ブチルの１１６の間にあるので簡単のため、分子量１００、密度０．８ｇ／ｃｍ^３で代表させる。Ｐｂ（ｄｐｍ）_２１ｍｏｌと溶媒２．４ｍｏｌの混合物の容積は、およそ
Ｐｂ（ｄｐｍ）_２分＋溶媒分＝（５７４／１．５２）＋（２４０／０．８）＝３７８＋３００＝６７８ｍｌ
である。すなわちＰｂ（ｄｐｍ）_２濃度は１／０．６７８＝１．４７ｍｏｌ／ｌとなる。これは平衡状態の場合であり、実際には達成されないので、より多くの溶媒とより高い気化器温度が必要となる。
【００１８】
以上のことから、Ｐｂ（ｄｐｍ）_２１ｍｏｌ／ｌ溶液は、気化器圧力１０Ｔｏｒｒ、気化器温度２５０℃程度で気化できると考えられる。Ｈｅ，Ａｒ，Ｎ_２などのイナートガスが共存すれば、より低い気化器温度で気化できる。また気化器圧力が５Ｔｏｒｒと低ければ、より低い気化器温度で気化できる。もちろん気化器の構造や使用方法で、詰まりや溶媒の先飛びを起こさない工夫は必要である。
表１のＴＨＦ、トルエン、酢酸ｎ−ブチル、シクロヘキサン、メチルシクロヘキサンであればＰｂ（ｄｐｍ）_２０．５ｍｏｌ／ｌ程度の溶液にできるので好都合である。
【００１９】
Ｔｉ（ＯｔＢｕ）_４は、融点４℃の室温で液体の化合物で、その物性はＺｒ（ＯｔＢｕ）_４に非常によく似ている。それぞれの物性を表２に記す。
【００２０】
【表２】

【００２１】
どちらも単量体であり、混合した場合、混じり合うだけで、会合することはない。物性も似ているので、完全に均一な混合液ができる。気化器直前の配管で混合しても、原料容器中で混合しても全く問題は起きない。また水分や酸素がなければ、気化器温度１５０℃でも熱分解することはない。
【００２２】
Ｚｒ（ＯｔＢｕ）_４とＴｉ（ＯｔＢｕ）_４とは、一つの原料容器中で所定の比で混合したものを使うのが好ましい。そうすれば、ＺｒとＴｉの混合均一性が良く、マスフローコントローラーが１基でよく、そのフロー制御の精度も少し低くても良いという利点がある。
Ｚｒ（ＯｔＢｕ）_４とＴｉ（ＯｔＢｕ）_４との混合比は、膜組成、成膜温度、Ｐｂ（ｄｐｍ）_２の共存などに影響されるので、あらかじめ実験により、求めておけばよい。
【００２３】
ＰｂＴｉＯ_３の下地層を形成後、ＰＺＴを成膜する場合には、上記Ｚｒ（ＯｔＢｕ）_４とＴｉ（ＯｔＢｕ）_４との混合物の入った原料容器Ａと、Ｔｉ（ＯｔＢｕ）_４の入った原料容器Ｂを、セットして使った方がよい。これであれば、マスフローコントローラーは、１基でもよく、かつ、Ｂ使用の場合でも、Ａ使用の場合でも、その精度は少し低くてもよい。
しかし、Ｚｒ（ＯｔＢｕ）_４の入った原料容器ＣとＴｉ（ＯｔＢｕ）_４の入った原料容器Ｂがセットされた場合、ＰＺＴ成膜時には二つのマスフローコントローラーは高い精度が求められる。これは工業上避けるべきである。
【００２４】
本発明では、ＰＺＴ成膜の基板温度を４００〜５００℃とできる。Ｐｂ，Ｚｒ，Ｔｉ源が共に低温堆積可能な化合物であるので、このような低温でも良好な強誘電性を示す膜が得られる。
【００２５】
ＣＶＤ室の圧力は、０．００１〜１０Ｔｏｒｒである。好ましくは、０．０１〜３Ｔｏｒｒである。圧力が３Ｔｏｒｒより高いと、気化器圧力が１０Ｔｏｒｒ程度に高くならざるを得ない。その結果、Ｐｂ（ｄｐｍ）_２が気化しにくくなるので、濃度を下げ、多くの溶媒を使ったり、多くのキャリヤーガスを使ったり、より高温にせざるを得なくなる。高濃度の溶媒が存在すると、Ｐｂ／（Ｚｒ＋Ｔｉ）＝１のプロセスウィンドウが狭くなる。これらの欠点を除くためには、できるだけ低圧が好ましいが、あまり低くなると、成膜速度が低下する。
【００２６】
酸化ガスとしては、Ｏ_２，Ｏ_３，Ｎ_２Ｏ，ＮＯ_２などが使える。低温化にはこれらの種類の選択とプラズマなどのアシスト法を使うとよい。
【００２７】
ＰＬＺＴの場合も上記のことがそのまま当てはまる。Ｌａ原料としては、Ｌａ（ｄｐｍ）_３、Ｌａ（ｄｉｂｍ）_３［トリス（ジイソブチリルメタナート）ランタン］などが使える。低温化には、後者のが好ましい。また後者の方が種々の溶媒に良く溶けるので、少ない溶媒で供給気化できる。これらのＬａ化合物とＰｂ（ｄｐｍ）_２とを所定の比で混合し一つの原料容器から供給すれば、組成の精度や均一性がよく、マスフローコントローラーが１基で２原料を送れるなどの工業的利点がある。
【００２８】
【実施例】
ＰＺＴ薄膜の製造
原料容器１からＰｂ（ｄｐｍ）_２のシクロヘキサン溶液（濃度０．５ｍｏｌ／ｌ）をマスフローコントローラー１を通し、２４０℃の気化器１に送り、予熱したＡｒガス３００ｓｃｃｍとともに蒸発させ、ガス混合部に送った。原料容器２からＺｒ（ＯｔＢｕ）_４とＴｉ（ＯｔＢｕ）_４のモル比０．３５／０．６５の生の混合液０．１０ｍｌ／ｍｉｎをマスフローコントローラー２を通し、１４０℃の気化器２に送り、予熱したＡｒガス７０ｓｃｃｍとともに蒸発させ、ガス混合部に送った。２つの気化器の圧力は成り行きで５〜７Ｔｏｒｒであった。混合部からのＰｂ，Ｚｒ，Ｔｉ化合物のガスと、予熱したＯ_２ガス４００ｓｃｃｍをＣＶＤ室のシャワーヘッドに導入し、Ｐｔ／ＳｉＯ_２／Ｓｉ基板上に導いた。ＣＶＤ室圧力は、１．０Ｔｏｒｒで、基板温度は４８０℃であった。２０分成膜し２００〜２５０ｎｍの膜が得られた。ＸＲＤ分析より、膜は正方晶のペロブスカイトであった。膜の一部を溶解し、ＩＣＰ発光分光で組成分析を行った。Ｐｂ（ｄｐｍ）_２溶液の供給速度との関係を表３に示す。
【００２９】
【表３】

【００３０】
この結果から、Ｐｂ（ｄｐｍ）_２供給速度０．５０〜０．６０ｍｌ／ｍｉｎ間で、膜組成Ｐｂ／（Ｚｒ＋Ｔｉ）＝１．００〜１．０１が達成され、プロセスウィンドウが開いたことがわかる。またＺｒ／Ｔｉも０．３８〜０．３９と一定にできたことがわかる。
【００３１】
【発明の効果】
液体マスフローコントローラーと気化器を使った原料供給方式で、ＰＺＴ膜を成膜する際、膜組成Ｐｂ／（Ｚｒ＋Ｔｉ）＝１となるプロセスウィンドウが開き、Ｚｒ／Ｔｉが一定にできる。ＰＺＴやＰＬＺＴ膜の量産に有効である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing PZT and PLZT thin films by chemical vapor deposition (hereinafter referred to as CVD).
[0002]
[Prior art]
PbZr _1-y Ti _y O ₃ (0 <y <1, hereinafter referred to as PZT) or (Pb _1-x , La _x ) (Zr _1-y , Ti _y ) O ₃ (0 <x <1, 0 <y <1) (hereinafter referred to as PLZT) As a method for producing a thin film with high productivity, a CVD method is used. As the raw material supply system, there are a system in which each compound of Pb, Zr, Ti and La is vaporized and supplied as it is, and a system in which it is vaporized and supplied as a solution. The latter is more suitable for mass production.
[0003]
Pb supply in which the film composition becomes autonomous with Pb / (Zr + Ti) = 1 in the former type of CVD in which the respective compounds of Pb (dpm) ₂ , Zr (OtBu) ₄ , and Ti (OiPr) ₄ are vaporized and supplied as they are. The process window opens widely. Aratani et al, Jpn. J. et al. Appl. Phys. Vol. 40, 4126 (2001). Here, the process window refers to a region of a raw material supply rate and a ratio thereof where the film composition Pb / (Zr + Ti) = 1.0. For example, it refers to the range of the supply ratio in which the film composition Pb / (Zr + Ti) = 1.0 is maintained even if the supply ratio of the Pb raw material to the (Zr + Ti) raw material changes. If Pb / (Zr + Ti) deviates from 1.0, the ferroelectric properties are deteriorated. Therefore, it is difficult to adopt as a mass production process unless the process window is wide open.
However, it has been found that the solution vaporization method has a problem that the CVD rate is lowered and there is almost no process window because a large amount of solvent is present during CVD.
[0004]
Regarding this problem, Ozeki et al., Proceedings of the 49th Japan Society of Applied Physics, p511 (2002.3), Pb (dpm) ₂ / octane (0.1 mol / l), Zr (OtBu) ₄ / octane (0 0.1 mol / l), Ti (OiPr) ₄ / octane (0.1 mol / l) solution vaporization method, and the result of CVD at 500 and 600 ° C. As a result, the deposition amount is reduced and there is no process window Has been reported.
M.M. Miyake et al, Jpn. J. et al. Appl. Phys. Vol. 41,241 _{(2002), Pb (dpm) 2 /THF(0.05mol/l),Zr(dibm)} 4 /THF(0.1mol/l),Ti(OiPr) 2 (dpm) 2 / THF ( In the solution vaporization method using 0.1 mol / l), CVD was performed at 20 Torr and 550 ° C., but the presence of a process window is not described.
Otani et al., The 49th JSAP Meeting Proceedings p511 (2002. ₂ ), [Pb (methd) ₂ + Zr (methd) ₄ + Ti (mpd) (methd) ₂ ] / ethylcyclohexane (0.049,0 As a result of performing CVD at 3 Torr and 550 ° C. substrate temperature with a solution vaporization method using 0.03 mol / l), the Pb composition of the film was sensitively influenced by the Pb concentration of the solution, and the process window did not open I have announced that. Here, methodd is [1- (2-methoxy) ethoxy-2,2,6,6-tetramethyl-3,5-heptanedionate], and mpd is [2-methyl-2,4-pentanedioxy]. To express.
Y. -S. Park, Integrated Ferroelectrics, Vol. 39,231 (2001) is Pb (dpm) ₂ / heptane (0.05 mol / l), Zr (OiPr) ₂ (dpm) ₂ / heptane (0.05 mol / l), Ti (OiPr) ₂ (dpm) It discloses that the process window did not open as a result of CVD at 480 to 570 ° C. in a solution vaporization method using ₂ / heptane (0.05 mol / l).
[0005]
As described above, there is still no report that a process window has been opened in a method of manufacturing a PZT film by CVD using a solution vaporization method.
[0006]
Zr raw materials used in the solution vaporization method are Zr (dpm) ₄ , Zr (OiPr) ₂ (dpm) ₂ , Zr (OiPr) (dpm) ₃ , Zr (divm) ₄ , Zr (methd) _4, etc. However, it has been found that there is a problem that incorporation of Zr into the film by CVD is unstable. The Zr / Ti ratio of the PZT film needs to be controlled to a predetermined value because it determines the crystal type of the PZT film and the ferroelectric characteristics.
If the Zr uptake is unstable, the Zr / Ti ratio is affected, which is a problem.
[0007]
A method of manufacturing a thin film at a substrate temperature of 500 ° C. or lower, preferably 450 ° C. or lower, since a highly integrated and multi-layered semiconductor device can be obtained by making a PZT nonvolatile memory at a temperature lower than the Al wiring can withstand. Is disclosed in Japanese Patent Laid-Open No. 2000-58526. However, this embodiment is not a solution vaporization method but a method using no solvent at all.
[0008]
The liquid raw material of Zr (OtBu) ₄ or Ti (OiPr) ₄ is preferable for mass production because it can send a large amount of gas by supplying it with a liquid mass flow controller and a vaporizer rather than bubbling. A method of vaporizing and supplying raw liquid alkoxide with a liquid mass flow controller and a vaporizer is industrialized with Si (OEt) ₄ and Ta (OEt) ₅ . However, in order to maintain the ratio of Zr (OtBu) ₄ and Ti (OiPr) _{4 at} a predetermined value with high accuracy, it is necessary to control their supply amounts with high accuracy with the respective liquid mass flow controllers. Is not easy. Instead of using two liquid mass flow controllers, Zr (OtBu) ₄ and Ti (OiPr) ₄ may be mixed at a predetermined ratio in one raw material container. This method cannot be used because a precipitate is formed.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a raw material system and a supply system that can facilitate the mass production of a PZT film because a method using a liquid mass flow controller and a vaporizer is preferable. Another object of the present invention is to provide a method in which the amount of solvent is reduced as much as possible so that the process window can be easily opened, the Zr / Ti ratio can be maintained at a predetermined value, and a film can be formed even at a low temperature of 500 ° C.
[0010]
[Means for Solving the Problems]
The present inventor uses only Pb (dpm) ₂ as a solution, and other Zr and Ti raw materials use raw volatile alkoxides, and Ti (OtBu) ₄ which does not react with Zr (OtBu) ₄ as a Ti source. ₄ is used, a mixed solution having a predetermined Zr / Ti ratio can be formed in one raw material container, a Pb (dpm) ₂ solution is vaporized by the vaporizer 1, and a mixed solution of Zr (OtBu) ₄ and Ti (OtBu) _{4 is} used. When the gas was vaporized in the vaporizer 2 and then combined with gas, it was found that CVD can be performed without causing an unfavorable reaction and a process window is opened, and the present invention has been completed.
[0011]
The present invention relates to a method for producing a PZT thin film by chemical vapor deposition, in which a bis (β-diketonate) lead solution is vaporized by a vaporizer 1 and Zr (OtBu) ₄ and Ti ( OtBu) ₄ is mixed in a predetermined ratio with the vaporizer 2, the gas from the two vaporizers and the oxidant are mixed, led to the CVD chamber, and the substrate temperature is 400 to 500 ° C. This is a method for producing a PZT thin film characterized by forming a film.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Examples of bis (β-diketonato) lead used in the present invention include Pb (dpm) ₂ , [bis (2,2,6,6-tetramethyl-3,5-octanedionate) lead], bis (2, 2,6-trimethyl-3,5-heptanedionate) lead, bis (6-ethyl-2,2-dimethyl-3,5-octanedionate) lead, Pb (methd) ₂ , and the like. Pb (dpm) ₂ that is easily available and has the highest thermal stability is preferable.
[0013]
In order to minimize the amount of solvent entering the CVD chamber, the solvent of the bis (β-diketonate) lead solution used in the present invention has a high solubility, such as Zr (OtBu) ₄ or Ti (OtBu) ₄ . It must be difficult to react.
Examples that meet these requirements include THF, toluene, butyl acetate, cyclohexane, methylcyclohexane, and ethylcyclohexane. Table 1 shows the mass (unit: g) of Pb (dpm) ₂ dissolved in 1 L of various solvents at room temperature.
[0014]
[Table 1]

[0015]
In order to reduce the amount of the solvent as much as possible, it is desirable to use a solvent having high Pb (dpm) ₂ solubility, lower the vaporizer pressure as much as possible, and raise the vaporizer temperature as much as possible. However, considering the low vapor pressure and thermal stability of Pb (dpm) ₂ , the range is approximately 200 to 250 ° C.
[0016]
The saturated vapor pressure of Pb (dpm) ₂ is expressed by the following Clausius-Clapeyron equation as a result of measurement by the present inventors at 130 to 170 ° C. by the gas saturation method.
Log ₁₀ P = −4480 / T + 9.94 P: Torr, T: K)
Further, when the boiling point of Pb (dpm) ₂ at Ar 1 atmosphere was examined by TG-DTA, it was 350 to 359 ° C. Since this agrees well with the value 361 ° C. obtained from the extrapolation of the vapor pressure equation, the extrapolation of the equation is reliable. Accordingly, when the saturated vapor pressure of Pb (dpm) ₂ is determined from the above equation, they are 3.0 Torr / 200 ° C. and 24 Torr / 250 ° C.
[0017]
If the gas temperature in the vaporizer is completely equal to the vaporizer temperature, when the vaporizer pressure is 10 Torr at 200 ° C., if there is a solvent for (10−3.0 =) 7.0 Torr, in principle The whole amount can be gaseous. That is, the minimum required amount of solvent is (7.0 / 3.0 =) 2.4 times the mol amount of Pb (dpm) ₂ . Since the molecular weight of the solvent in Table 1 is between 72 in THF and 116 in butyl acetate, it is represented by a molecular weight of 100 and a density of 0.8 g / cm ³ for simplicity. The volume of the mixture of 1 mol of Pb (dpm) ₂ and 2.4 mol of solvent is approximately Pb (dpm) ₂ minutes + solvent content = (574 / 1.52) + (240 / 0.8) = 378 + 300 = 678 ml
It is. That is, the Pb (dpm) ₂ concentration is 1 / 0.678 = 1.47 mol / l. This is an equilibrium case and is not achieved in practice, so more solvent and higher vaporizer temperatures are required.
[0018]
From the above, it is considered that the Pb (dpm) ₂ 1 mol / l solution can be vaporized at a vaporizer pressure of 10 Torr and a vaporizer temperature of about 250 ° C. If inert gases such as He, Ar, and N ₂ coexist, vaporization can be performed at a lower vaporizer temperature. If the vaporizer pressure is as low as 5 Torr, vaporization can be performed at a lower vaporizer temperature. Of course, the structure and usage of the vaporizer must be devised to prevent clogging and solvent jumping.
The THF, toluene, n-butyl acetate, cyclohexane, and methylcyclohexane shown in Table 1 are convenient because a solution of about 0.5 mol / l Pb (dpm) ₂ can be obtained.
[0019]
Ti (OtBu) ₄ is a liquid compound at room temperature with a melting point of 4 ° C., and its physical properties are very similar to Zr (OtBu) ₄ . Each physical property is shown in Table 2.
[0020]
[Table 2]

[0021]
Both are monomers, and when mixed, they only mix and do not associate. Since the physical properties are similar, a completely uniform mixture can be obtained. There is no problem at all even if it is mixed in the pipe immediately before the vaporizer or mixed in the raw material container. If there is no moisture or oxygen, thermal decomposition will not occur even at a vaporizer temperature of 150 ° C.
[0022]
Zr (OtBu) ₄ and Ti (OtBu) ₄ are preferably mixed in a predetermined ratio in one raw material container. If it does so, there exists an advantage that the mixing uniformity of Zr and Ti is good, one mass flow controller may be sufficient, and the precision of the flow control may be a little low.
The mixing ratio of Zr (OtBu) ₄ and Ti (OtBu) ₄ is influenced by the film composition, the film forming temperature, the coexistence of Pb (dpm) ₂ , and so forth, and may be obtained beforehand through experiments.
[0023]
When forming a PZT film after forming an underlayer of PbTiO ₃ , a raw material container A containing a mixture of Zr (OtBu) ₄ and Ti (OtBu) ₄ and a raw material containing Ti (OtBu) ₄ It is better to set and use the container B. In this case, the number of mass flow controllers may be one, and the accuracy may be a little lower when B is used or when A is used.
However, when the raw material container C containing Zr (OtBu) ₄ and the raw material container B containing Ti (OtBu) ₄ are set, the two mass flow controllers are required to have high accuracy during the PZT film formation. This should be avoided industrially.
[0024]
In the present invention, the substrate temperature for PZT film formation can be set to 400 to 500 ° C. Since the Pb, Zr, and Ti sources are both compounds that can be deposited at a low temperature, a film showing good ferroelectricity can be obtained even at such a low temperature.
[0025]
The pressure in the CVD chamber is 0.001 to 10 Torr. Preferably, it is 0.01 to 3 Torr. If the pressure is higher than 3 Torr, the vaporizer pressure must be increased to about 10 Torr. As a result, Pb (dpm) ₂ is less likely to be vaporized, so the concentration must be lowered, a large amount of solvent, a large amount of carrier gas, or a higher temperature must be used. In the presence of a high concentration of solvent, the process window of Pb / (Zr + Ti) = 1 is narrowed. In order to eliminate these drawbacks, a low pressure is preferable as much as possible. However, if the pressure is too low, the film formation rate decreases.
[0026]
As the oxidizing gas, O ₂ , O ₃ , N ₂ O, NO ₂ or the like can be used. For lowering the temperature, it is better to select these types and use an assist method such as plasma.
[0027]
The same applies to PLZT. As the La raw material, La (dpm) ₃ , La (divm) ₃ [Tris (diisobutyrylmethanate) lanthanum] and the like can be used. The latter is preferred for lowering the temperature. Further, since the latter is more soluble in various solvents, it can be supplied and vaporized with less solvent. If these La compounds and Pb (dpm) ₂ are mixed in a predetermined ratio and supplied from one raw material container, the composition accuracy and uniformity are good, and the mass flow controller can send two raw materials in one unit. There are advantages.
[0028]
【Example】
Manufacture of PZT thin film A cyclohexane solution of Pb (dpm) ₂ (concentration 0.5 mol / l) is sent from the raw material container 1 to the vaporizer 1 at 240 ° C. through the mass flow controller 1 and evaporated together with 300 sccm of preheated Ar gas. It was sent to the mixing section. A raw mixture 0.10 ml / min of Zr (OtBu) ₄ and Ti (OtBu) _{4 in} a molar ratio of 0.35 / 0.65 is sent from the raw material container 2 to the vaporizer 2 at 140 ° C. through the mass flow controller 2. Then, it was evaporated together with a preheated Ar gas of 70 sccm and sent to the gas mixing section. The pressure in the two vaporizers was 5-7 Torr on the way. Pb, Zr, Ti compound gas from the mixing section and 400 sccm of preheated O ₂ gas were introduced into the shower head in the CVD chamber and led onto the Pt / SiO ₂ / Si substrate. The CVD chamber pressure was 1.0 Torr and the substrate temperature was 480 ° C. The film was formed for 20 minutes, and a film having a thickness of 200 to 250 nm was obtained. From XRD analysis, the film was tetragonal perovskite. A part of the film was dissolved, and composition analysis was performed by ICP emission spectroscopy. Table 3 shows the relationship with the supply rate of the Pb (dpm) ₂ solution.
[0029]
[Table 3]

[0030]
From this result, it can be seen that the film composition Pb / (Zr + Ti) = 1.00 to 1.01 was achieved between the Pb (dpm) ₂ supply rate of 0.50 to 0.60 ml / min, and the process window was opened. . It can also be seen that Zr / Ti can be kept constant at 0.38 to 0.39.
[0031]
【The invention's effect】
When a PZT film is formed by a raw material supply method using a liquid mass flow controller and a vaporizer, a process window in which the film composition Pb / (Zr + Ti) = 1 is opened, and Zr / Ti can be made constant. This is effective for mass production of PZT and PLZT films.

Claims (1)

In a method for producing a PZT thin film by chemical vapor deposition, a bis (β-diketonato) lead solution is vaporized by a vaporizer 1 and Zr (OtBu) contained in one raw material container. ₄ And Ti (OtBu) ₄ The gas mixture from the two vaporizers and the oxidant are mixed, led to the CVD chamber, and formed on a substrate having a substrate temperature of 400 to 500 ° C. A process for producing a PZT thin film characterized by the above.