JPH05229827A - Method for forming ferroelectric film - Google Patents

Method for forming ferroelectric film

Info

Publication number
JPH05229827A
JPH05229827A JP3185592A JP3185592A JPH05229827A JP H05229827 A JPH05229827 A JP H05229827A JP 3185592 A JP3185592 A JP 3185592A JP 3185592 A JP3185592 A JP 3185592A JP H05229827 A JPH05229827 A JP H05229827A
Authority
JP
Japan
Prior art keywords
film
crystal
ferroelectric film
substrate
crystal grains
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.)
Pending
Application number
JP3185592A
Other languages
Japanese (ja)
Inventor
Kazuya Ishihara
数也 石原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Priority to JP3185592A priority Critical patent/JPH05229827A/en
Publication of JPH05229827A publication Critical patent/JPH05229827A/en
Priority to US08/321,470 priority patent/US5443030A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To obtain a ferroelectric film having improved film quality by depositing a film of a Pb-containing composition on a substrate and heating with a lamp at a prescribed temperature, thereby converting the deposited film to a perovskite crystal structure. CONSTITUTION:A Pb-containing film 1 having a prescribed composition such as PZT (PbZrxTi1-xO3) is deposited on a substrate by sputtering process or a sol-gel process. Light is radiated exclusively to the film 1 on the substrate using a halogen lamp, etc., and the film is heated at 550-650 deg.C for about 1min. The film is converted to a perovskite crystal structure to form a ferroelectric film 1'. A number of crystal nuclei 2 are formed in the film 1' by the quick- heating procedure and crystal grains 3 are grown on the nuclei. The crystal grains 3 are soon brought into contact with each other and the growth of the crystal is stopped while the crystal diameter is still small to get a ferroelectric film 1' containing crystal grains 3 having optimum diameters. In contrast with the above process, the crystal nuclei 12 in the film 11 are excessively grown in the case of heating with an electric furnace to get a heat-treated ferroelectric film 11' having too large crystal grains 13 to keep the film from cracking.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】この発明は、強誘電体膜形成方法
に関し、より詳しくは、Ｐbを組成に含む強誘電体膜を
形成する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a ferroelectric film, and more particularly to a method for forming a ferroelectric film containing Pb in its composition.

【０００２】[0002]

【従来の技術】Ｐbを組成に含む強誘電体膜としては、
ＰＺＴ(ＰbＺrxＴi1-xＯ3)、ＰＬＺＴ((Ｐb1-xＬax)(Ｚ
ryＴi1-y)1-x/4Ｏ3)などが知られている。従来、この種
の強誘電体膜を形成する場合、まず、スパッタリング法
またはゾルゲル法により、Ｐbを含む所定の組成を有す
る膜を基板に堆積する。この後、この基板をボートにセ
ットして電気炉に入れて、不活性ガス中で温度５５０〜
６５０℃,数時間程度の熱処理を行う。これにより、堆
積した膜(非晶質)をペロブスカイト型結晶構造に変化さ
せて強誘電性を持たせ、強誘電体膜を形成している。2. Description of the Related Art As a ferroelectric film containing Pb in its composition,
PZT (PbZr x Ti 1-x O 3), PLZT ((Pb 1-x La x) (Z
r y Ti 1-y ) 1-x / 4 O 3 ) and the like are known. Conventionally, when forming this type of ferroelectric film, first, a film having a predetermined composition containing Pb is deposited on a substrate by a sputtering method or a sol-gel method. After that, the substrate is set in a boat and put in an electric furnace, and the temperature is set to 550 in an inert gas.
Heat treatment is performed at 650 ° C. for several hours. As a result, the deposited film (amorphous) is changed to a perovskite type crystal structure to have ferroelectricity and a ferroelectric film is formed.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、従来の
形成方法は、上記熱処理を電気炉を用いて行っているの
で、上記基板およびボートを昇温して安定させるため
に、どうしても３０分間程度の時間がかかる。このた
め、図１(b)に示すように、堆積した膜１１中に存在し
ている結晶核１２が過度に成長して、熱処理後に強誘電
体膜１１′中の結晶粒１３が大きくなり過ぎるという問
題がある。このように膜中の結晶粒１３が大きくなり過
ぎた場合、ストレスが発生して強誘電体膜１１′にクラ
ックが生じたり、導電性が高くなって半導体素子の誘電
体膜として適用できなくなったりする。However, in the conventional forming method, since the heat treatment is performed using an electric furnace, in order to raise the temperature of the substrate and the boat and stabilize them, a time of about 30 minutes is inevitable. Takes. Therefore, as shown in FIG. 1 (b), the crystal nuclei 12 existing in the deposited film 11 grow excessively and the crystal grains 13 in the ferroelectric film 11 'become too large after the heat treatment. There is a problem. When the crystal grains 13 in the film become too large in this way, stress is generated and cracks occur in the ferroelectric film 11 ', or the conductivity is so high that it cannot be applied as a dielectric film of a semiconductor element. To do.

【０００４】また、上記強誘電体膜の組成の中では、Ｐ
bの蒸気圧が最も高くなっており、図２(b)に示すよう
に、上記長時間の熱処理中にＰb成分がＰbＯの状態で膜
１１中から多量に蒸発する(図には、堆積後の組成と熱
処理後の組成を示している。)。このため、堆積する膜
１１に予め１０〜２０mol％の過剰のＰb成分を加えてお
かねばならず、しかも、上記ＰbＯの蒸発によって強誘
電体膜１１′中にピンホールが生じて膜質が損なわれる
という問題がある。In the composition of the ferroelectric film, P
The vapor pressure of b is the highest, and as shown in FIG. 2 (b), a large amount of Pb component evaporates from the film 11 in the state of PbO during the heat treatment for a long time (in the figure, after the deposition, The composition and the composition after heat treatment are shown.). Therefore, 10 to 20 mol% of excess Pb component must be added to the deposited film 11 in advance, and the evaporation of PbO causes pinholes in the ferroelectric film 11 'to deteriorate the film quality. There is a problem.

【０００５】そこで、この発明の目的は、Ｐbを組成に
含む強誘電体膜を適正寸法の結晶粒を有する状態に形成
でき、しかも、熱処理中のＰbＯの蒸発を抑えて、予め
過剰のＰb成分を加えておく必要を無くすとともにピン
ホール発生量を低減できる強誘電体膜形成方法を提供す
ることにある。Therefore, an object of the present invention is to form a ferroelectric film containing Pb in its composition in a state having crystal grains of an appropriate size, and to suppress the evaporation of PbO during heat treatment, thereby preliminarily producing an excessive Pb component. Another object of the present invention is to provide a method for forming a ferroelectric film, which eliminates the need to add the above and reduces the amount of pinholes generated.

【０００６】[0006]

【課題を解決するための手段】上記目的を達成するた
め、この発明の強誘電体膜形成方法は、Ｐbを含む所定
の組成を有する膜を基板に堆積した後、所定の温度で熱
処理を行って、上記堆積した膜をペロブスカイト型結晶
構造に変化させて強誘電体膜を形成する強誘電体膜形成
方法において、上記熱処理をランプ加熱によって行うこ
とを特徴としている。In order to achieve the above object, in the method for forming a ferroelectric film of the present invention, a film having a predetermined composition containing Pb is deposited on a substrate, and then heat treatment is performed at a predetermined temperature. Then, in the ferroelectric film forming method of forming the ferroelectric film by changing the deposited film into a perovskite type crystal structure, the heat treatment is performed by lamp heating.

【０００７】[0007]

【作用】ランプ加熱、すなわちハロゲンランプなどを用
いて対象物に光を照射する加熱法によれば、基板に堆積
した膜のみを、約１分間程度で急速に加熱することがで
きる。このように急速に加熱した場合、膜中に従来に比
して多数の結晶核が形成され、結晶粒はこの核をシード
(種子)として成長する結果、結晶粒同士がぶつかり合っ
て粒径が小さい状態で成長が止まる。したがって、強誘
電体膜が適正寸法の結晶粒を有する状態に形成される。
また、熱処理が短時間で行なわれることから、熱処理の
前後で膜中のＰb量がほとんど一定に保たれる。したが
って、予め過剰のＰb成分を加えておく必要が無くなる
とともに、ピンホールの発生量が減少して膜質が良くな
る。According to the lamp heating, that is, the heating method of irradiating the object with light using a halogen lamp or the like, only the film deposited on the substrate can be rapidly heated in about 1 minute. When heated rapidly like this, a larger number of crystal nuclei are formed in the film than in the past, and the crystal grains seed these nuclei.
As a result of growing as a (seed), the crystal grains collide with each other and the growth stops in a state where the grain size is small. Therefore, the ferroelectric film is formed in a state of having crystal grains of appropriate size.
Further, since the heat treatment is performed in a short time, the amount of Pb in the film is kept almost constant before and after the heat treatment. Therefore, it is not necessary to add an excessive Pb component in advance, and the amount of pinholes generated is reduced to improve the film quality.

【０００８】[0008]

【実施例】以下、この発明の強誘電体膜形成方法を実施
例により詳細に説明する。EXAMPLES The ferroelectric film forming method of the present invention will be described in detail below with reference to examples.

【０００９】Ｐbを組成に含む強誘電体膜として、ＰＺ
Ｔ(ＰbＺrxＴi1-xＯ3)膜またはＰＬＺＴ((Ｐb1-xＬax)
(ＺryＴi1-y)1-x/4Ｏ3)膜を形成するものとする。 まず、スパッタリング法またはゾルゲル法により、上
記組成を有する膜を基板に堆積する。このとき、堆積す
る膜の組成は、化学量論的組成比とする。 次に、図１(a)に示すように、上記堆積した膜(参照数
字１で表す。)に対して、ハロゲンランプを用いて光を
照射して(ランプ加熱)、温度５５０〜６５０℃,１分間
の熱処理を行う。これにより、基板に堆積した膜(非晶
質)１のみを加熱して、ペロブスカイト型結晶構造に変
化させて強誘電体膜１′を形成する。このように急速に
加熱した場合、図１(a)に示すように、膜１中に従来に
比して多数の結晶核２が形成され、結晶粒はこの核をシ
ード(種子)として成長する。この結果、結晶粒同士がぶ
つかり合って粒径が小さい状態で成長が止まる。したが
って、強誘電体膜１′を適正寸法の結晶粒３を有する状
態に形成することができる。また、熱処理を短時間で行
えることから、図２(a)に示すように、堆積後と熱処理
後とで、膜１,１′中のＰb量をほとんど一定に保つこと
ができる。したがって、工程で述べたように、堆積す
る膜１の組成は、化学量論的組成比とするだけで済む。
しかも、ピンホールの発生量を減少させて、膜質を良く
することができる。As a ferroelectric film containing Pb in its composition, PZ
T (PbZr x Ti 1-x O 3) film or PLZT ((Pb 1-x La x)
A (Zr y Ti 1-y ) 1-x / 4 O 3 ) film is formed. First, a film having the above composition is deposited on a substrate by a sputtering method or a sol-gel method. At this time, the composition of the deposited film is a stoichiometric composition ratio. Next, as shown in FIG. 1 (a), the deposited film (denoted by reference numeral 1) is irradiated with light using a halogen lamp (lamp heating) to obtain a temperature of 550 to 650 ° C. Heat treatment is performed for 1 minute. As a result, only the film (amorphous) 1 deposited on the substrate is heated to change into a perovskite type crystal structure and a ferroelectric film 1'is formed. When heated rapidly in this way, as shown in FIG. 1 (a), a larger number of crystal nuclei 2 are formed in the film 1 than in the conventional case, and the crystal grains grow using these nuclei as seeds. . As a result, the crystal grains collide with each other and the growth stops in the state where the grain size is small. Therefore, the ferroelectric film 1'can be formed in a state having the crystal grains 3 of appropriate size. Further, since the heat treatment can be performed in a short time, as shown in FIG. 2A, the amount of Pb in the films 1 and 1'can be kept almost constant after the deposition and after the heat treatment. Therefore, as described in the process, the composition of the film 1 to be deposited only needs to be a stoichiometric composition ratio.
Moreover, the quality of the film can be improved by reducing the amount of pinholes generated.

【００１０】[0010]

【発明の効果】以上より明らかなように、この発明の強
誘電体膜形成方法は、基板に堆積した膜の熱処理をラン
プ加熱によって行っているので、急速加熱によって多数
の結晶核を形成する結果、強誘電体膜を適正寸法の結晶
粒を有する状態に形成することができる。しかも、熱処
理を短時間で行えるので、熱処理の前後で膜中のＰb量
をほとんど一定に保つことができる。したがって、予め
過剰のＰbＯ成分を加える必要が無くなるとともに、ピ
ンホールの発生量を減少させて膜質を良くすることがで
きる。As is apparent from the above, in the ferroelectric film forming method of the present invention, the heat treatment of the film deposited on the substrate is performed by the lamp heating, so that a large number of crystal nuclei are formed by the rapid heating. The ferroelectric film can be formed in a state having crystal grains of appropriate size. Moreover, since the heat treatment can be performed in a short time, the amount of Pb in the film can be kept almost constant before and after the heat treatment. Therefore, it is not necessary to add an excessive PbO component in advance, and the amount of pinholes generated can be reduced to improve the film quality.

【図面の簡単な説明】[Brief description of drawings]

【図１】 この発明の一実施例の強誘電体膜形成方法お
よび従来の強誘電体膜形成方法を説明する図である。FIG. 1 is a diagram illustrating a ferroelectric film forming method according to an embodiment of the present invention and a conventional ferroelectric film forming method.

【図２】 上記実施例および従来の強誘電体膜形成方法
により形成した強誘電体膜の組成を示す図である。FIG. 2 is a diagram showing a composition of a ferroelectric film formed by the above-mentioned embodiment and a conventional ferroelectric film forming method.

【符号の説明】[Explanation of symbols]

１,１１ 堆積膜 １′,１１′ 強誘電体膜 ２,１２ 結晶核 ３,１３ 結晶粒 1,11 Deposited film 1 ', 11' Ferroelectric film 2,12 Crystal nuclei 3,13 Crystal grains

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 Ｐbを含む所定の組成を有する膜を基板
に堆積した後、所定の温度で熱処理を行って、上記堆積
した膜をペロブスカイト型結晶構造に変化させて強誘電
体膜を形成する強誘電体膜形成方法において、 上記熱処理をランプ加熱によって行うことを特徴とする
強誘電体膜形成方法。1. A ferroelectric film is formed by depositing a film having a predetermined composition containing Pb on a substrate and then performing heat treatment at a predetermined temperature to change the deposited film into a perovskite type crystal structure. A method of forming a ferroelectric film, wherein the heat treatment is performed by heating a lamp.
JP3185592A 1992-01-08 1992-02-19 Method for forming ferroelectric film Pending JPH05229827A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP3185592A JPH05229827A (en) 1992-02-19 1992-02-19 Method for forming ferroelectric film
US08/321,470 US5443030A (en) 1992-01-08 1994-10-11 Crystallizing method of ferroelectric film

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3185592A JPH05229827A (en) 1992-02-19 1992-02-19 Method for forming ferroelectric film

Publications (1)

Publication Number Publication Date
JPH05229827A true JPH05229827A (en) 1993-09-07

Family

ID=12342667

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3185592A Pending JPH05229827A (en) 1992-01-08 1992-02-19 Method for forming ferroelectric film

Country Status (1)

Country Link
JP (1) JPH05229827A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100339608B1 (en) * 1998-12-30 2002-10-25 주식회사 하이닉스반도체 PZT thin film formation method of semiconductor device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100339608B1 (en) * 1998-12-30 2002-10-25 주식회사 하이닉스반도체 PZT thin film formation method of semiconductor device

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