JP3626421B2 - Method and apparatus for forming metal oxide thin film - Google Patents

Description

【００４６】
表１から分かるように、燃焼室の温度を４００℃の試料でもっとも高い誘電率と低いリーク電流（特に上部電極に正電圧を印加（下部Ｒｕ電極からの電子注入に相当））が得られていることがわかる。これは燃焼室でｎブチル酢酸をあらかじめ燃焼し、基板上での熱発生を抑制して、膜厚方向に均一なＳＴＯ膜を形成することができた結果、界面の組成比が化学量論比からずれた低誘電率層がなくなったこと、またこの低誘電率層が酸素欠損を多く含んでいるために絶縁性が低いことにより流れるリーク電流が抑制されたためと考えられる。
【００４７】
以上説明したように、燃焼室で原料ガスと酸素とを混合して、予備加熱して原料ガス中の有機溶媒ガスをあらかじめ燃焼させてしまうことで、貴金属電極等が触媒となり、原料ガス中の有機溶媒ガスを基板近傍で燃焼し、基板温度を上昇させてしまう現象を抑制できる。
【００４８】
その結果、基板温度上昇にともなう薄膜と貴金属電極との界面付近での組成が化学量論比からずれてしまい、膜質が劣化してしまう現象を抑制できる。また、酸化剤が有機溶媒と優先的に反応せず、原料ガス中の有機金属化合物あるいは有機金属錯体と反応できるようになるので、該薄膜中の酸素欠損生成が抑制され、優れた膜質例えば絶縁性の高い薄膜を得ることができる。
【００４９】
本実施形態のようなコールドウォール型装置では、反応容器の壁面温度自体は耐熱性、強度確保の観点から３００℃以上に上げることは困難である。また、一般に液体原料供給系の気化器と反応容器の距離とが短いので、配管自体の加熱で原料ガスを昇温することは困難である。本実施形態のように、気化器と反応容器との間に燃焼室を設け、ここで原料ガスを昇温し、酸化剤との反応を十分に行うことで前項に記載されたような、貴金属電極上で組成が化学量論比からずれる、膜中に酸素欠損が多量に生成される等の問題を抑制できる。
【００５０】
（第２の実施形態）
本実施形態はＳＴＯのホットウォールバッチ型ＣＶＤ装置の多孔インジェクタ内にＣＶＤ原料ガスと酸素とを混合させて導入し、ＣＶＤ原料ガス中の有機溶媒と酸素をインジェクタ内で反応させて燃焼させるものである。
【００５１】
図５は、第２の実施形態に係わるホットウォール型ＣＶＤ装置の概略構成を示す模式図である。図５において、図２と同様な部位には同一符号を付し、その説明を省略する。
本装置は、図５に示すように、第１の実施形態と同様に、液体原料供給系２０１、反応容器２０２、排気系２０３から構成される。反応容器２０２は炉内に挿入された石英製の二重管（内管２０４と外管２０５）になっており、成膜に使われる原料ガスは内管２０４内に直接または多孔インジェクタ２０６を通して導入され、内管２０４と外管２０５の間を通って排気される。成膜が行われる基板は石英製のボート２０７上に移載されており、ボート２０７自体は反応容器の蓋を兼ねたボートエレベーター２０８上の保温筒２０９上に置かれている。上記保温筒２０９は内蔵ヒーターで自由に温度を変えられるように設計されている。ボートは炉の均熱領域に位置するようになっている。
【００５２】
ＳＴＯを成膜するために、本装置では、Ｓｒ（ＤＰＭ）_２の０．５Ｍ／Ｌ ＴＨＦ溶液を２ｓｃｃｍ、Ｔｉ（ＤＰＭ）_２（ｉ−ＯＣ_３Ｈ_７）_２の０．５Ｍ／Ｌ ＴＨＦ（Ｃ_４Ｈ_８Ｏ）溶液を１．８ｓｃｃｍ混合して、２６０℃設定の気化器１０７で気化させた。気化圧力は５ｋＰａである。
【００５３】
また、第１の実施形態と同様に、熱電対つきウエハーをボート２０７に載置して、触媒効果による熱発生を評価する場合には、ＴＨＦのみ４．８ｓｃｃｍを２６０℃に設定された気化器１０７で気化させた。キャリアガスであるアルゴンガスの流量は８００ｓｃｃｍである。アルゴンガスと混合された原料ガスはそのまま、または３ＳＬＭの酸素と混合され、多孔インジェクタ内に導入され、ウエハー２枚あたり一つ設けられた吹き出し口を通って基板２１０近傍まで輸送される。
【００５４】
上述した装置構成で第１の実施形態と同様に、熱電対つきＲｕ／ＳｉＯ_２ ／Ｓｉウエハーをボート２０７上に載置した後、炉温を５００℃に固定し、保温筒温度を変えて基板温度がどのように変化するかを評価した。また、比較例として酸素を下側から流し、原料ガスのみ多孔インジェクタを通して供給した場合を示した。その結果を図６に示す。
【００５５】
図６からわかるように、原料ガスのみ多孔インジェクタを通して供給した場合、Ｒｕつき基板の温度上昇は５０℃と第１の実施形態の枚葉式ＣＶＤ装置の場合と殆ど変らない結果が得られた。これに対して酸素と原料ガスを多孔インジェクタを通して供給した場合、特に保温筒の加熱を行わない場合でも、基板の温度上昇は３０℃と小さくなることがわかる。
【００５６】
更に保温筒自体を加熱していくと、基板温度の上昇幅は縮小していき、保温筒中心部の温度が４５０℃になった場合でほぼ温度上昇は観察されなくなった。
【００５７】
ホットウォール型ＣＶＤ装置の場合、原料ガスはインジェクタ内を輸送される過程で炉からの輻射で加熱されるため、酸素と原料ガスとを同じインジェクタで供給するだけでも酸素と有機溶媒の反応がおこり、結果として基板上での熱発生が抑制されたたものと考えられる。この場合でも、保温筒として自己加熱できる仕様のものを採用することで触媒反応を抑制する効果を高めることができる。
【００５８】
そこで、保温筒の自己加熱を採用するかわりに、ガスが炉体から受け取る熱による溶媒の燃焼反応をより促進するために、図７（ａ）〜（ｃ）に示すような３種類の多孔インジェクタを作製し、原料ガスと酸素とを同時に多孔インジェクタ内に流し、原料ガスと酸素が吹き出し口から基板に供給されるまでにインジェクタ内を流れる距離をかえることで有機溶媒の燃焼反応を促進することをこころみた。図７に示した３種類の多孔インジェクタによる基板温度上昇幅の違いを表２に示す。なお、表２では、図７（ａ），（ｂ），（ｃ）に示すインジェクタをそれぞれインジェクタＡ，インジェクタＢ、インジェクタＣとしている。
【００５９】
【表２】

【００６０】
原料ガスと酸素が一緒に流れる距離が長い方が基板温度上昇を抑制する効果が大きく、特に反応管内で一回折り返した形状（インジェクタＣ）の分散ノズルでは、基板温度上昇がほぼ０になることがわかる。従って表２より、インジェクタ形状を工夫してガスが流れる実効的距離を増やすことでも、貴金属つき基板上での熱発生をほぼ０にすることができることがわかる。
【００６１】
ホットウォール型装置では、有機溶媒を含んだ原料ガスと酸化剤とを混合して流すことで、反応容器による加熱がおこなわれ、有機溶媒を基板に到達する前に酸化剤と反応させて分解することができる。その結果、貴金属電極上で薄膜の組成が化学量論比からずれる、膜中に酸素欠損が多量に生成される等の問題を抑制できる。
【００６２】
（第３の実施形態）
本実施形態はＳＢＴ膜のホットウォール枚葉型ＣＶＤ装置に、本発明を適用した例である。本装置のガスインジェクタ内に原料ガスと酸素とを混合させて導入しホットウォールの炉温を制御することで、ＣＶＤ原料ガス中の有機溶媒と酸素を反応させて燃焼させるものである。
【００６３】
図８は、第３の実施形態に係わるホットウォール型枚葉ＣＶＤ装置の概略構成を示す模式図である。図８において、図２と同一な部分には同一符号を付し、その説明を省略する。
【００６４】
本装置は、図８に示すように、第１及び第２の実施形態と同様に、液体原料供給系３０１、反応容器３０２、排気系３０３よりなる。反応容器３０２は炉３１０内に挿入された石英管３０４であり、成膜に使われるガスは石英管３０４内に直接、またはインジェクタ３０５を通して導入され一旦石英管３０４上面にふきつけられた後、拡散により基板３０６に供給される。基板３０６は石英製のサセプタ３０７に移載され、ヒーター３０８によって加熱される。すなわち、本装置では基板加熱機構としてホットウォール方式の炉３１０と基板を直接加熱できるヒーターの２つの独立した機構を有することになる。
【００６５】
本装置では、ＳｒＢｉ_２Ｔａ_２Ｏ_９膜を形成するために、液体原料としてＳｒ（ＤＰＭ）_２、Ｂｉ（ＤＰＭ）_３、Ｔａ（ＤＰＭ）（ＯＣ_２Ｈ_５）_４の０．１５Ｍ／ＬＴＨＦ溶液を用いる。総流量は０．３５ｓｃｃｍである、また比較のためにＴＨＦのみ０．３５ｓｃｃｍを供給することを試みた。気化器の設定温度は２４０℃、気化圧力は１ｋＰａであった。キャリアガスであるアルゴンガス流量は３００ｓｃｃｍである。アルゴンガスと混合された原料ガスは酸素ガスと混合、または単独でインジェクタ内に導入され、反応容器３０２に供給される。
【００６６】
上記装置構成で熱電対つきＰｔ／ＳｉＯ_２ ／Ｓｉウエハーをボート上に積載し、サセプタ温度を一定に保って、基板温度を５００℃に設定した。最初に炉の温度を２５０℃に保って、▲１▼インジェクタ３０５からＴＨＦと酸素とを一緒に供給する、▲２▼インジェクタからＴＨＦ、石英管内に直接酸素を供給するの二通りの方法で、基板温度の変化を評価した。その結果、▲１▼▲２▼いずれの場合も基板温度の上昇幅は約５０℃と大差なかった。
【００６７】
次に炉温を２５０℃から５００℃まで昇温していき、▲１▼▲２▼の条件について基板温度の上昇幅を評価した。その結果を図９に示す。図９からわかるように、ＴＨＦのみインジェクタを通して供給した場合、炉温を高めていってもＰｔつき基板の温度上昇はやや減少するにとどまる結果が得られた。これに対して酸素とＴＨＦをインジェクタを通して供給した場合、炉温度が３５０℃を超えた付近から基板の温度上昇幅が縮小していき、炉の温度が４５０℃になった場合でほぼ温度上昇は観察されなくなった。すなわち、酸素とＴＨＦがインジェクタ３０５内及び石英管３０４上面で燃焼反応をおこした結果として、Ｐｔつき基板上での熱発生が抑制されたものと考えられる。
【００６８】
上記▲１▼及び▲２▼の方法で既述の原料供給条件で６０ｎｍのＳＢＴ膜を作製し、電気特性を評価した。炉温としては４５０℃を採用した。基板温度は５００℃である。５００℃で成膜したＳＢＴ膜は非晶質になるので７００℃酸素１００％常圧雰囲気中で１０分熱処理を施して結晶化した。上部電極としてスパッタ法でＰｔ膜を形成、周知のフォトリソグラフィ技術及びＲＩＥ技術により、上部電極をパターニングした後、ダメージ除去として７００℃酸素雰囲気中１ｍｉｎ．のＲＴＡを行った。その結果図１０に示すような残留分極特性、図１１に示すような疲労特性が得られた。
【００６９】
本発明の方法（▲１▼）で、より対称性がよいヒステリシス曲線高い残留分極値、強い疲労耐性が得られていることがわかる。これは触媒効果を抑制したことにより、下部電極界面での欠陥発生が抑制され、上下電極界面の差が小さくなったためと考えられる。
【００７０】
ホットウォール型装置では、有機溶媒を含んだ原料ガスと酸化剤とを混合して流すことで、反応容器による加熱がおこなわれ、有機溶媒を基板に到達する前に酸化剤と反応させて分解することができる。その結果、貴金属電極上で薄膜の組成が化学量論比からずれる、膜中に酸素欠損が多量に生成される等の問題を抑制できる。
【００７１】
なお、本発明は、上記実施形態に限定されるものではない。例えば、気化器のキャリアガスとして酸素ガス、乃至は酸素アルゴン混合ガスを用いることも有効である。この場合、気化器下流での酸素分圧を高めることができるので、よりインジェクタ内や燃焼室内での効果的な溶媒燃焼を実現することができる。
また、酸化剤として、酸素以外のガスを用いることもできる。
その他、本発明は、その要旨を逸脱しない範囲で、種々変形して実施することが可能である。
【００７２】
【発明の効果】
以上説明したように本発明によれば、金属有機化合物、または金属有機錯体化合物を有機溶媒に溶解した溶液を気化した原料ガスと酸化剤とを混合して有機溶媒を燃焼させた後、被成膜基板に供給することによって、原料ガス中の有機溶媒ガスを基板近傍で燃焼し、基板温度を上昇させてしまう現象を抑制できる。その結果、基板温度上昇にともなう薄膜と貴金属電極との界面付近での組成が化学量論比からずれてしまい、膜質が劣化してしまう現象を抑制できる。また、酸化剤が有機溶媒と優先的に反応せず、原料ガス中の有機金属化合物あるいは有機金属錯体と反応できるようになるので、該薄膜中の酸素欠損生成が抑制され、優れた膜質例えば絶縁性の高い薄膜を得ることができる。
【図面の簡単な説明】
【図１】ＴＨＦの燃焼効率の温度依存性を示す特性図。
【図２】第１の実施形態に係わる枚葉型ＭＯＣＶＤ装置の概略構成を示す模式図。
【図３】燃焼室１０８の設定温度を気化温度と同じ２５０℃から４００℃まで変えていったときの、熱電対つきＲｕ／ＳｉＯ_２ ／Ｓｉ基板の温度の上昇幅を示す特性図。
【図４】燃焼室の温度が２５０℃、３５０℃、４００℃の３つの成膜条件で成膜されたＳＴＯ膜の（Ｂａ＋Ｓｒ）／Ｔｉ比の膜厚方向の組成プロファイルを示す図。
【図５】第２の実施形態に係わるホットウォール型ＣＶＤ装置の概略構成を示す模式図。
【図６】保温筒温度に対する基板温度の上昇幅を示す特性図。
【図７】第２の実施形態に係わる多孔インジェクタの概略構成を示す図。
【図８】第３の実施形態に係わるホットウォール型枚葉ＣＶＤ装置の概略構成を示す模式図。
【図９】保温筒温度に対する基板温度の上昇幅を示す特性図。
【図１０】残留分極特性を示す特性図。
【図１１】疲労特性を示す図。
【符号の説明】
１０１…液体原料供給系
１０２…反応容器
１０３…排気系
１０４…液体原料容器
１０５…ミキシングマニホールド
１０６…液体流量制御器
１０７…気化器
１０８…燃焼室
１０９…シャワーノズル
１１０…被成膜基板
１１１…サセプタ
１１２…ヒータ
１１３…メカニカル・ブースター・ポンプ
１１４…ドライ真空ポンプ[0001]
BACKGROUND OF THE INVENTION
In the present invention, a gas generated by vaporizing a solution in which a metal organic compound or a metal organic complex compound is dissolved in an organic solvent is supplied onto a film formation substrate, and film formation is performed by chemical vapor deposition. The present invention relates to a metal oxide thin film forming method and a film forming apparatus.
[0002]
[Prior art]
As electronic devices become smaller in size, not only can the functions of electronic devices be achieved with only a circuit configuration, but also the functions of the devices can be realized by utilizing the characteristics of materials such as functional thin films themselves. It is becoming advantageous. For example, an SRAM (Static Random Access read write Memory) that performs information storage operation with a combination of transistors, an EEPROM (Electrically Erasable and Programmable Read Only Memory), or a DRAM that performs an information storage operation with a combination of a transistor and a capacitor. It is very difficult to realize an integrated circuit such as Memory) by conventional MOS transistors and MOS capacitors as the cell area of these elements is reduced. In particular, in order to prevent the S / N ratio from being lowered even if the minimum processing size of the integrated circuit is reduced, it is necessary to continue to ensure a certain capacitance of the capacitor element, and a silicon oxide film as a capacitor dielectric film of the capacitor element Ta which expresses higher dielectric constant than silicon nitride film / silicon oxide film stack film (NO film) ₂ O ₅ , Ba _x Sr _1-x TiO ₃ (BST) and SrTiO ₃ (STO), PbZr _x Ti _1-x O ₃ (PZT), SrBi ₂ Ta ₂ O ₉ The adoption of a functional material thin film such as (SBT) has been studied, and a device having a completely new function such as FeRAM (Ferroelectric Random Access read Memory) using the ferroelectricity of PZT or SBT. Has begun to be proposed.
[0003]
Ta mentioned above ₂ O ₅ , BST, PZT, SBT, etc. are promising as capacitor dielectric films, but since all are metal oxides, it is possible to use doped polycrystalline silicon films that have been used as capacitor electrodes for NO films as electrodes. Can not. This is because when polycrystalline silicon is used as an electrode, a silicon oxide film formed by oxidizing the surface of the polycrystalline silicon during metal oxide film formation serves as a low dielectric constant layer. In addition, since BST, PZT, SBT, etc. have high film forming temperatures, Ta ₂ O ₅ Metal electrodes such as TiN and WN, which have been studied as film electrodes, are not suitable as electrodes because an insulating metal oxide is formed at the electrode dielectric interface. Therefore, when forming a capacitor element of a highly integrated semiconductor integrated circuit using a high (strong) dielectric film made of a metal oxide, platinum is hardly oxidized as an electrode material and is still a conductor even when oxidized. Adoption of noble metals such as ruthenium and iridium is essential.
[0004]
On the other hand, as a method for forming a PZT or BST capacitor dielectric film, the CVD method is most suitable in consideration of the fact that application to a three-dimensional capacitor is unavoidable in the progress of high integration. When these dielectric films are formed by a CVD method, an MOCVD method using an organic compound or an organic complex of the metal as a raw material is suitable. This is because there are few metal halides constituting these dielectric films exhibiting a higher vapor pressure than organic compounds of the same metal (for example, some organic complexes of Sr vaporize from around 200 ° C. In the case of a halide, heating at 300 ° C. or higher is necessary.) If the source gas contains halogen, the halogen is incorporated into the dielectric film during film formation, and the film quality (for example, withstand voltage) is deteriorated. Because it invites.
[0005]
On the other hand, organometallic complexes such as Sr, Pb, and Ti have a problem of causing thermal deterioration when stored at a high temperature (for example, 200 ° C. or higher) at which a sufficient vapor pressure is obtained. Accordingly, a liquid phase supply method is widely adopted in which a solution in which these organic compounds are dissolved in an organic solvent is prepared, the solution is weighed and transported at room temperature, and vaporized at once with a high-temperature vaporizer. In the liquid phase supply method, since most of the liquid piping is at room temperature, heat deterioration of the raw material is unlikely to occur, and the gas piping can be minimized, so heating to prevent recondensation of the gasified raw material is performed. There is an advantage that the number of special parts such as a high-temperature valve can be reduced and the number of special parts can be reduced.
[0006]
In the metal oxide thin film such as BST, STO, PZT, etc., which are formed by MOCVD method with the raw material supplied by the liquid phase supply method, in the region near the interface with the noble metal as the lower electrode, an excessive oxide of Ti or Zr As a result of precipitation, the insulating properties are deteriorated. Further, in the case of SBT, the Bi deposition amount decreases and the Ta deposition amount increases, and the insulating property is deteriorated.
[0007]
Further, in the metal oxide thin film in the vicinity of the interface, there is a problem that oxygen deficiency occurs and the composition ratio deviates from the stoichiometric ratio. Such oxygen vacancies have a problem of acting as a donor and causing a decrease in insulation and acceleration of film fatigue. In addition, since a poor film is formed at the interface, there are problems that the dielectric constant decreases when the film is thinned, and the insulation property is drastically lowered, making it difficult to thin the dielectric film. .
[0008]
[Problems to be solved by the invention]
As described above, when the metal oxide thin film is formed on the noble metal electrode by the MOCVD method using the liquid phase supply method, the composition ratio of the thin film near the interface with the noble metal electrode is deviated from the stoichiometric ratio. was there. When the composition ratio deviates from the stoichiometric ratio, there is a problem in that it is difficult to reduce the thickness of the dielectric film due to deterioration of insulating properties and reduction of dielectric constant.
[0009]
The object of the present invention is to suppress the deviation from the stoichiometric ratio of the composition ratio in the vicinity of the interface with the noble metal film when the metal oxide thin film is formed on the noble metal electrode by the MOCVD method using the liquid phase supply method. Then, it is providing the film-forming method and film-forming apparatus of the metal oxide thin film which can be thinned.
[0010]
[Means for Solving the Problems]
[Constitution]
The present invention is configured as follows to achieve the above object.
[0011]
(1) A method for forming a metal oxide thin film according to the present invention includes a chemical vapor phase using a gas obtained by vaporizing a solution of a metal organic compound or a metal organic complex compound dissolved in an organic solvent as a main source gas. In a method for forming a metal oxide thin film in which a metal oxide thin film is formed on a deposition target substrate by a growth method, the source gas and an oxidant are mixed before the source gas reaches the deposition target substrate. By mixing and preheating, at least a part of the organic solvent in the gas is decomposed.
[0012]
Preferred embodiments of the present invention are described below.
A noble metal film or a compound film containing a noble metal as a main component exists in at least a part of the surface layer of the deposition target substrate.
The preheating temperature is 320 ° C. or higher.
[0013]
(2) A film forming apparatus according to the present invention includes a vaporizer that vaporizes a solution in which a metal organic compound or a metal organic complex compound is dissolved in an organic solvent to generate a gas, and the gas generated in the vaporizer and the oxidation A combustion chamber that mixes the agent and decomposes at least a part of the organic solvent in the gas by a heating mechanism, and a gas is supplied from the combustion chamber to the inside, and the chemical is deposited on the deposition target substrate installed inside the combustion chamber. And a reaction chamber in which a film is formed by a vapor deposition method.
[0014]
(3) A film forming apparatus according to the present invention vaporizes a solution in which a metal organic compound or a metal organic complex compound is dissolved in an organic solvent to generate a gas, and transports the gas generated by the vaporizer However, a transport path for mixing the oxidizing agent, a heating mechanism for heating the transport path to decompose at least a part of the organic solvent in the gas in the transport path, and at least one of the organic solvents by the heating mechanism. And a reaction chamber for forming a film by a chemical vapor deposition method on a deposition target substrate provided therein and supplied with a gas whose portion is decomposed. As the heating mechanism, it is preferable to use a furnace for heating the reaction vessel from the outside.
[0015]
[Action]
The present invention has the following operations and effects by the above configuration.
[0016]
By burning the organic solvent gas in the raw material gas in advance, the noble metal electrode or the like becomes a catalyst, and the organic solvent gas in the raw material gas is burned in the vicinity of the substrate to increase the substrate temperature. As a result, it is possible to suppress a phenomenon in which the composition near the interface between the thin film and the noble metal electrode with a rise in substrate temperature deviates from the stoichiometric ratio and the film quality deteriorates. In addition, since the oxidizing agent does not react preferentially with the organic solvent and can react with the organometallic compound or organometallic complex in the raw material gas, generation of oxygen vacancies in the thin film is suppressed, and excellent film quality such as insulation is achieved. A thin film with high properties can be obtained.
[0017]
By preheating at 320 ° C. or higher, the organic solvent can be started to burn. Moreover, since it cannot be made higher than 600 degreeC with most film-forming apparatuses, combustion temperature will be 600 degrees C or less. Note that if the combustion temperature is equal to or higher than the film formation temperature, thin film growth occurs on the inner wall. Therefore, the combustion temperature is more preferably lower than the film formation temperature.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
(Cause of the problem)
According to the earnest study of the present inventors, when a metal oxide thin film is formed on a noble metal electrode by the MOCVD method using a liquid phase supply method, the composition ratio in the vicinity of the interface with the noble metal film deviates from the stoichiometric ratio. The cause of the problem was found as follows.
[0019]
Precious metals such as ruthenium and platinum have a strong catalytic effect, and when the system temperature is set to a temperature range of about 400 ° C. to 600 ° C. in the state where the precious metal serving as a catalyst, the organic material serving as a fuel, and the oxidizing agent coexist, It has the property of explosively accelerating combustion. As a result, a large amount of heat is generated due to the combustion of the organic matter. As a result of intensive studies, heat generation due to the catalytic effect of the noble metal continues until a dielectric film is formed on the surface of the noble metal to a thickness of about 5 nm, and then calms down when the dielectric film is formed to a thickness of 5 nm or more.
[0020]
Ba _x Sr _1-x TiO ₃ (BST) or PbZr _x Ti _1-x O ₃ In a multi-component metal oxide thin film such as (PZT), the control of the composition is very important in controlling the film characteristics. In order to form a multi-component metal oxide thin film on a three-dimensional structure with good step coverage using CVD, a reaction rate-limiting condition in which the supply rate of each metal raw material is sufficiently higher than the deposition rate of each metal However, since the deposition rate of each metal is a function of the deposition temperature under the reaction rate-determining conditions, changing the deposition temperature while keeping the supply rate of each metal material constant changes the film composition. Resulting in.
[0021]
Ba _x Sr _1-x TiO ₃ , SrTiO ₃ (STO) and PbZr _x Ti _1-x O ₃ In this CVD film, the deposition amount of Ti and Zr tends to increase as the film formation temperature is increased. When heat is generated by a catalytic reaction, heat is generated only on the noble metal electrode. Therefore, the amount of increase in the substrate temperature depends on the coverage of the noble metal electrode on the substrate, and a Ti or Zr excess dielectric film is formed. Thus, the excessive amount of Ti or Zr itself tends to have a distribution on the substrate.
[0022]
In BST, STO, and PZT films, Ti and Zr-excess films have low dielectric constants, and excessive Ti and Zr oxides precipitate, resulting in deterioration of insulation. Since this catalytic reaction does not occur when the metal oxide thin film is formed to have a thickness of 5 nm or more, a BST film or a PZT film having a low dielectric constant and low insulating film of about 5 nm at the interface is obtained.
[0023]
The case of PZT, BST, and STO film has been described above, but SrBi ₂ Ta ₂ O ₉ In this case, it is known that the decrease in Bi deposition amount and the increase in Ta deposition amount are caused by heat generation by catalytic reaction.
[0024]
In addition, in a situation where a catalytic reaction is occurring, oxygen gas is preferentially used for solvent combustion, so that not enough oxygen for metal oxide formation is supplied, and the dielectric film is not supplied. Oxygen vacancies are easily formed.
[0025]
As explained above, the composition ratio of the metal oxide thin film deviates from the stoichiometric ratio in the vicinity of the interface with the noble metal film because of the heat generation due to the combustion of the solvent in the source gas due to the catalytic effect of the noble metal. Heat generation can be suppressed by removing the solvent from the source gas. However, as long as the liquid phase supply is used, it is difficult to use no solvent, and it is also difficult to separate and remove only the solvent from the gasified raw material.
[0026]
Therefore, the present inventors focused on the temperature difference between the vaporization temperature and the film formation temperature, preheated in a state in which the source gas sent from the vaporizer and the oxidizing agent were mixed, and burned before the solvent reached the substrate. Tried to let you. As a result, it was confirmed that the catalytic effect of the noble metal was suppressed and a high-quality dielectric film could be formed.
[0027]
The result of examining the combustion temperature of THF (tetrahydrofuran) often used as an organic solvent is shown in FIG. In FIG. 1, after flowing a mixed gas of THF and oxygen through a quartz tube heated to a constant temperature, the temperature dependence of the combustion efficiency of THF is analyzed by analyzing with a quadrupole mass spectrometer (Quadrupole Mass Spectrometer). The results of the investigation are shown. As the pressure, two conditions of 1 Torr and 10 Torr were examined. 1 Torr corresponds to the pressure during the actual film formation of the reaction vessel, and 10 Torr corresponds to the pressure in the piping when the source gas is transported to the reaction vessel.
[0028]
As can be seen from FIG. 1, the combustion of THF starts at around 300 ° C., and almost 100% is combusted at 450 ° C. or higher. Further, the combustion efficiency is pressure dependent, and at 10 Torr, the combustion efficiency is 20% or more at 320 ° C. or more. From this, it can be seen that in order to efficiently burn THF, it is efficient to burn it during transportation in a pipe up to a high-pressure reaction tube, and the combustion temperature is preferably 320 ° C. or higher. .
[0029]
Moreover, it is preferable that combustion temperature is 600 degrees C or less. This upper limit of the combustion temperature arises because it is difficult to make the gas higher than 600 ° C. as an apparatus configuration. However, if the temperature is higher than the film formation temperature, thin film growth occurs on the inner wall of the pipe and causes dust, so it is more preferable to set the combustion temperature lower than the film formation temperature.
[0030]
That is, by using this method, the heat generation on the noble metal electrode can be suppressed by mixing the solvent in the raw material gas with the oxidizing agent and burning it by preheating, and as a result, BST, PZT, etc. The composition ratio deviates from the stoichiometric ratio in the vicinity of the noble metal electrode interface of the dielectric film, and the generation of a large amount of oxygen vacancies in the film can be suppressed. As a result, a high-quality compound thin film, for example, a high dielectric film can be stably formed and the film thickness can be reduced. If this dielectric thin film is used as a capacitor element of a semiconductor integrated circuit, it is possible to manufacture an ultrathin capacitor having an extremely high accumulated charge capability, and to manufacture a memory element having a high degree of integration.
[0031]
Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
In this embodiment, a combustion chamber in which an organic solvent and oxygen are reacted and burnt is provided between a vaporizer of a BST single wafer type MOCVD apparatus and a reaction vessel.
[0032]
FIG. 2 is a schematic diagram showing a schematic configuration of the single wafer MOCVD apparatus according to the first embodiment of the present invention.
[0033]
As shown in FIG. 2, this apparatus mainly includes a liquid source supply system 101, a reaction vessel 102, and an exhaust system 103. The liquid material supply system 101 includes a Ba, Sr, Ti liquid material container 104 pressurized with He gas, a mixing manifold 105 for mixing these liquid materials at a desired ratio, and the mixed materials at a constant speed. A liquid flow rate controller 106 to be transported and a vaporizer 107 for vaporizing the raw material whose flow rate is controlled by the liquid flow rate controller 106. Note that the total liquid flow rate supplied from the liquid flow rate controller 106 to the vaporizer 107 was 0.2 sccm.
[0034]
The liquid raw material stored in the liquid raw material container 104 is Ba (DPM). ₂ ・ Tetraglyme, Sr (DPM) ₂ ・ Tetraglyme, TiO (DPM) ₂ Of 0.15 M / L n-butylacetic acid (CH ₃ COOC ₄ H ₉ ) Solution was used. DPM is C ₁₁ H ₁₉ O ₂ , Tetraglyme is C ₆ H ₁₄ O ₂ It is.
[0035]
The exhaust system 103 includes a mechanical booster pump (MBP) 113 and a dry vacuum pump (DRP) 114.
[0036]
The vaporization conditions in the vaporizer 107 were a set temperature of 250 ° C. and a vaporization pressure of 2 kPa. The raw material gas vaporized in the vaporizer 107 is mixed with the carrier gas Ar and introduced into the combustion chamber 108 through a pipe heated to 250 to 260 ° C.
[0037]
In the combustion chamber 108, oxygen and source gas are mixed and heated while passing through a narrow tube set to a desired temperature. The raw material gas exiting the combustion chamber 108 is introduced into the reaction vessel 102 through a pipe heated to 260 to 270 ° C. and a shower nozzle 109. In the combustion chamber 108, the temperature is set so that at least a part of the organic solvent in the raw material gas burns.
[0038]
In the shower nozzle 109, oxygen can be mixed with the source gas as required. A deposition target substrate 110 on which a dielectric film is deposited is placed on a susceptor 111 made of aluminum nitride and heated by a heater 112. A thermocouple is attached to the susceptor 111, and feedback control using a thermocouple indication value and temperature control using electric power supplied to the heater 112 are possible.
[0039]
The following tests were conducted to observe the catalytic effect of noble metals.
A film formation substrate whose temperature can be measured by a thermocouple (not shown) is placed on the susceptor while keeping the input power to the heater 112 constant under the condition that the temperature of the susceptor 111 is 550 ° C. Argon gas was allowed to flow from the shower nozzle at a flow rate of 1 SLM, and the pressure in the reaction vessel 102 was maintained at 1 Pa. As a result, the substrate temperature reached 500 ° C. In this state, even when oxygen was passed through the shower nozzle 109, no temperature change of the deposition target substrate 110 was observed. The deposition target substrate is SiO on a Si substrate. ₂ And Ru are sequentially stacked.
[0040]
Next, n-butylacetic acid gas and oxygen gas vaporized by the vaporizer 107 were mixed in the combustion chamber 108 and introduced into the reaction vessel through the shower nozzle 109. Ru / SiO with thermocouple when the set temperature of the combustion chamber 108 is changed from 250 ° C. to 400 ° C. which is the same as the vaporization temperature ₂ FIG. 3 shows the increase in the temperature of the / Si substrate.
[0041]
It was confirmed that when the combustion chamber temperature was set to 250 ° C., the same as that of the vaporizer, the substrate temperature increased by about 50 ° C. due to the catalytic effect as compared with the case where n-butylacetic acid was not introduced. On the other hand, when the temperature of the combustion chamber 108 is further increased to a temperature of 320 ° C. or higher, the temperature increase range of the deposition target substrate 110 becomes smaller, and the temperature of the combustion chamber 108 is 400 ° C. The rise was almost zero.
[0042]
Therefore, instead of a thermocouple substrate, Ru / SiO ₂ / Si substrate is introduced, the substrate temperature is controlled to 500 ° C., the BST raw material is introduced and vaporized into the vaporizer 107, and the temperature of the combustion chamber 108 is about 250 ° C., 350 ° C., 400 ° C. A 20 nm STO film was deposited.
[0043]
FIG. 4 shows the results obtained by measuring the composition profiles of Ba, Sr, and Ti atoms in the film thickness direction by Auger electron spectroscopy for these samples and obtaining the (Ba + Sr) / Ti ratio for each sample. When the temperature of the combustion chamber 108 is 250 ° C., a phenomenon in which the (Ba + Sr) / Ti composition ratio deviates from 1 in the stoichiometric ratio and rapidly decreases at the Ru interface is observed, but the temperature of the combustion chamber 108 is increased. It can be seen that the drop in the (Ba + Sr) / Ti composition ratio at the Ru interface decreases as the process proceeds.
[0044]
Table 1 shows the electrical characteristics of a planar capacitor formed by forming a Ru film as an upper electrode on an STO film obtained under three film formation conditions and processing by a normal photolithography technique and an RIE technique.
[0045]
[Table 1]

[0046]
As can be seen from Table 1, the sample with a combustion chamber temperature of 400 ° C. has the highest dielectric constant and low leakage current (particularly, a positive voltage is applied to the upper electrode (corresponding to electron injection from the lower Ru electrode)). I understand that. This is because n-butylacetic acid is burned in advance in the combustion chamber, and heat generation on the substrate is suppressed, and a uniform STO film can be formed in the film thickness direction. This is considered to be because the low dielectric constant layer deviated from this point disappeared, and because the low dielectric constant layer contained many oxygen vacancies, the leakage current flowing due to the low insulating property was suppressed.
[0047]
As described above, the source gas and oxygen are mixed in the combustion chamber, preheated, and the organic solvent gas in the source gas is burned in advance, so that the noble metal electrode or the like becomes a catalyst, The phenomenon that the organic solvent gas is burned in the vicinity of the substrate and the substrate temperature is raised can be suppressed.
[0048]
As a result, it is possible to suppress a phenomenon in which the composition near the interface between the thin film and the noble metal electrode with a rise in substrate temperature deviates from the stoichiometric ratio and the film quality deteriorates. In addition, since the oxidizing agent does not react preferentially with the organic solvent and can react with the organometallic compound or organometallic complex in the raw material gas, generation of oxygen vacancies in the thin film is suppressed, and excellent film quality such as insulation is achieved. A thin film with high properties can be obtained.
[0049]
In the cold wall type apparatus as in this embodiment, it is difficult to raise the wall temperature of the reaction vessel to 300 ° C. or more from the viewpoint of heat resistance and strength. Moreover, since the distance between the vaporizer of the liquid source supply system and the reaction vessel is generally short, it is difficult to raise the temperature of the source gas by heating the piping itself. As in the present embodiment, a combustion chamber is provided between the vaporizer and the reaction vessel, where the temperature of the raw material gas is raised and the reaction with the oxidizing agent is sufficiently performed, as described in the previous section, Problems such as the composition deviating from the stoichiometric ratio on the electrode and the generation of a large amount of oxygen vacancies in the film can be suppressed.
[0050]
(Second Embodiment)
In the present embodiment, a CVD source gas and oxygen are mixed and introduced into a porous injector of an STO hot wall batch type CVD apparatus, and an organic solvent and oxygen in the CVD source gas are reacted in the injector and burned. is there.
[0051]
FIG. 5 is a schematic diagram showing a schematic configuration of a hot wall type CVD apparatus according to the second embodiment. 5, parts that are the same as those in FIG. 2 are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 5, this apparatus includes a liquid source supply system 201, a reaction vessel 202, and an exhaust system 203, as in the first embodiment. The reaction vessel 202 is a quartz double tube (an inner tube 204 and an outer tube 205) inserted into the furnace, and a raw material gas used for film formation is introduced directly into the inner tube 204 or through a porous injector 206. And exhausted between the inner tube 204 and the outer tube 205. The substrate on which the film is formed is transferred onto a quartz boat 207, and the boat 207 itself is placed on a heat retaining cylinder 209 on a boat elevator 208 that also serves as a lid of the reaction vessel. The heat retaining cylinder 209 is designed so that the temperature can be freely changed by a built-in heater. The boat is located in the soaking area of the furnace.
[0052]
In order to form an STO film, this apparatus uses Sr (DPM) ₂ 2 sccm of 0.5 M / L THF solution of Ti (DPM) ₂ (I-OC ₃ H ₇ ) ₂ 0.5M / L THF (C ₄ H ₈ O) The solution was mixed at 1.8 sccm and vaporized by the vaporizer 107 set at 260 ° C. The vaporization pressure is 5 kPa.
[0053]
Similarly to the first embodiment, when a wafer with a thermocouple is mounted on the boat 207 and heat generation due to the catalytic effect is evaluated, a vaporizer in which 4.8 sccm of THF is set at 260 ° C. Vaporized at 107. The flow rate of argon gas as the carrier gas is 800 sccm. The raw material gas mixed with the argon gas is directly or mixed with oxygen of 3SLM, introduced into the porous injector, and transported to the vicinity of the substrate 210 through one blowout port provided for every two wafers.
[0054]
As with the first embodiment, Ru / SiO with a thermocouple is used in the apparatus configuration described above. ₂ After the / Si wafer was placed on the boat 207, the furnace temperature was fixed at 500 ° C., and how the substrate temperature was changed by changing the temperature of the insulation cylinder was evaluated. Further, as a comparative example, the case where oxygen was supplied from the lower side and only the source gas was supplied through the porous injector was shown. The result is shown in FIG.
[0055]
As can be seen from FIG. 6, when only the source gas was supplied through the porous injector, the temperature rise of the Ru-attached substrate was 50 ° C., which was almost the same as the case of the single wafer CVD apparatus of the first embodiment. On the other hand, when oxygen and source gas are supplied through a porous injector, it can be seen that the temperature rise of the substrate is as small as 30 ° C. even when the heat insulating cylinder is not heated.
[0056]
Further, when the heat insulating cylinder itself was heated, the increase in the substrate temperature was reduced, and when the temperature at the center of the heat insulating cylinder reached 450 ° C., the temperature increase was hardly observed.
[0057]
In the case of a hot wall type CVD apparatus, the source gas is heated by radiation from the furnace while it is transported through the injector, so that even if oxygen and source gas are supplied from the same injector, the reaction between oxygen and organic solvent occurs. As a result, it is considered that heat generation on the substrate was suppressed. Even in this case, the effect of suppressing the catalytic reaction can be enhanced by adopting a specification that can be self-heated as the heat insulating cylinder.
[0058]
Therefore, in order to further promote the combustion reaction of the solvent by the heat received by the gas from the furnace body instead of adopting the self-heating of the heat insulating cylinder, three kinds of porous injectors as shown in FIGS. To promote the combustion reaction of the organic solvent by changing the distance that the source gas and oxygen flow through the injector before the source gas and oxygen are supplied to the substrate from the outlet I tried. Table 2 shows the difference in the substrate temperature rise by the three types of porous injectors shown in FIG. In Table 2, the injectors shown in FIGS. 7A, 7B, and 7C are referred to as an injector A, an injector B, and an injector C, respectively.
[0059]
[Table 2]

[0060]
The longer the distance in which the source gas and oxygen flow together, the greater the effect of suppressing the substrate temperature rise. In particular, in the case of a dispersion nozzle having a shape that is folded once in the reaction tube (injector C), the substrate temperature rise is almost zero. I understand. Therefore, it can be seen from Table 2 that heat generation on the substrate with the noble metal can be reduced to almost zero even by devising the injector shape and increasing the effective distance through which the gas flows.
[0061]
In a hot wall type apparatus, a raw material gas containing an organic solvent and an oxidant are mixed and flowed, whereby heating by the reaction vessel is performed, and the organic solvent is reacted with the oxidant and decomposed before reaching the substrate. be able to. As a result, it is possible to suppress problems such as the composition of the thin film deviating from the stoichiometric ratio on the noble metal electrode and the generation of a large amount of oxygen vacancies in the film.
[0062]
(Third embodiment)
This embodiment is an example in which the present invention is applied to an SBT film hot wall single-wafer CVD apparatus. The raw material gas and oxygen are mixed and introduced into the gas injector of this apparatus, and the furnace temperature of the hot wall is controlled to cause the organic solvent and oxygen in the CVD raw material gas to react and burn.
[0063]
FIG. 8 is a schematic diagram showing a schematic configuration of a hot wall type single wafer CVD apparatus according to the third embodiment. In FIG. 8, the same parts as those in FIG.
[0064]
As shown in FIG. 8, this apparatus includes a liquid source supply system 301, a reaction vessel 302, and an exhaust system 303, as in the first and second embodiments. A reaction vessel 302 is a quartz tube 304 inserted into a furnace 310, and a gas used for film formation is introduced directly into the quartz tube 304 or through an injector 305 and once wiped onto the upper surface of the quartz tube 304, and then diffused. It is supplied to the substrate 306. The substrate 306 is transferred to a quartz susceptor 307 and heated by a heater 308. In other words, this apparatus has two independent mechanisms, ie, a hot wall type furnace 310 and a heater that can directly heat the substrate as the substrate heating mechanism.
[0065]
In this device, SrBi ₂ Ta ₂ O ₉ Sr (DPM) as a liquid raw material to form a film ₂ , Bi (DPM) ₃ , Ta (DPM) (OC ₂ H ₅ ) ₄ Of 0.15 M / L THF. The total flow rate is 0.35 sccm, and for comparison, an attempt was made to supply only 0.35 sccm of THF. The set temperature of the vaporizer was 240 ° C., and the vaporization pressure was 1 kPa. The flow rate of argon gas as the carrier gas is 300 sccm. The source gas mixed with the argon gas is mixed with oxygen gas or introduced into the injector alone and supplied to the reaction vessel 302.
[0066]
Pt / SiO with thermocouple in the above device configuration ₂ / The Si wafer was loaded on the boat, the susceptor temperature was kept constant, and the substrate temperature was set to 500 ° C. First, the furnace temperature is maintained at 250 ° C., and (1) THF and oxygen are supplied together from the injector 305, (2) THF and oxygen are supplied directly from the injector into the quartz tube, Changes in the substrate temperature were evaluated. As a result, in either case (1) or (2), the increase in the substrate temperature was not much different from about 50 ° C.
[0067]
Next, the furnace temperature was raised from 250 ° C. to 500 ° C., and the increase in the substrate temperature was evaluated under the conditions (1) and (2). The result is shown in FIG. As can be seen from FIG. 9, when only THF was supplied through the injector, the temperature rise of the Pt-attached substrate was only slightly reduced even when the furnace temperature was increased. On the other hand, when oxygen and THF are supplied through the injector, the temperature rise of the substrate is reduced from the vicinity where the furnace temperature exceeds 350 ° C., and the temperature rise is approximately when the furnace temperature reaches 450 ° C. No longer observed. That is, it is considered that heat generation on the substrate with Pt was suppressed as a result of the combustion reaction of oxygen and THF in the injector 305 and the upper surface of the quartz tube 304.
[0068]
A 60 nm SBT film was produced by the above methods (1) and (2) under the above-described raw material supply conditions, and the electrical characteristics were evaluated. As the furnace temperature, 450 ° C. was adopted. The substrate temperature is 500 ° C. Since the SBT film formed at 500 ° C. became amorphous, it was crystallized by heat treatment for 10 minutes in an atmosphere of 700 ° C. and 100% oxygen and atmospheric pressure. A Pt film is formed by sputtering as the upper electrode. After patterning the upper electrode by a well-known photolithography technique and RIE technique, damage removal is performed in a 700 ° C. oxygen atmosphere for 1 min. RTA was performed. As a result, remanent polarization characteristics as shown in FIG. 10 and fatigue characteristics as shown in FIG. 11 were obtained.
[0069]
It can be seen that with the method of the present invention (1), a hysteresis curve with better symmetry, a high remanent polarization value, and a strong fatigue resistance are obtained. This is considered to be because the occurrence of defects at the lower electrode interface was suppressed and the difference between the upper and lower electrode interfaces was reduced by suppressing the catalytic effect.
[0070]
In a hot wall type apparatus, a raw material gas containing an organic solvent and an oxidant are mixed and flowed, whereby heating by the reaction vessel is performed, and the organic solvent is reacted with the oxidant and decomposed before reaching the substrate. be able to. As a result, it is possible to suppress problems such as the composition of the thin film deviating from the stoichiometric ratio on the noble metal electrode and the generation of a large amount of oxygen vacancies in the film.
[0071]
The present invention is not limited to the above embodiment. For example, it is also effective to use oxygen gas or oxygen-argon mixed gas as the carrier gas for the vaporizer. In this case, since the oxygen partial pressure downstream of the vaporizer can be increased, more effective solvent combustion in the injector and the combustion chamber can be realized.
A gas other than oxygen can also be used as the oxidizing agent.
In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.
[0072]
【The invention's effect】
As described above, according to the present invention, after mixing a raw material gas obtained by vaporizing a solution in which a metal organic compound or a metal organic complex compound is dissolved in an organic solvent and an oxidizing agent, By supplying to the film substrate, it is possible to suppress the phenomenon that the organic solvent gas in the source gas is burned in the vicinity of the substrate and the substrate temperature is raised. As a result, it is possible to suppress a phenomenon in which the composition near the interface between the thin film and the noble metal electrode with a rise in substrate temperature deviates from the stoichiometric ratio and the film quality deteriorates. In addition, since the oxidizing agent does not react preferentially with the organic solvent and can react with the organometallic compound or organometallic complex in the raw material gas, generation of oxygen vacancies in the thin film is suppressed, and excellent film quality such as insulation is achieved. A thin film with high properties can be obtained.
[Brief description of the drawings]
FIG. 1 is a characteristic diagram showing the temperature dependence of the combustion efficiency of THF.
FIG. 2 is a schematic diagram showing a schematic configuration of a single wafer MOCVD apparatus according to the first embodiment.
FIG. 3 shows Ru / SiO with a thermocouple when the set temperature of the combustion chamber 108 is changed from 250 ° C. to 400 ° C. which is the same as the vaporization temperature. ₂ FIG. 6 is a characteristic diagram showing the temperature rise of the Si substrate.
FIG. 4 is a view showing a composition profile in the film thickness direction of (Ba + Sr) / Ti ratio of an STO film formed under three film formation conditions of a combustion chamber temperature of 250 ° C., 350 ° C., and 400 ° C.
FIG. 5 is a schematic diagram showing a schematic configuration of a hot wall type CVD apparatus according to a second embodiment.
FIG. 6 is a characteristic diagram showing an increase width of a substrate temperature with respect to a temperature keeping cylinder temperature.
FIG. 7 is a view showing a schematic configuration of a multi-hole injector according to a second embodiment.
FIG. 8 is a schematic diagram showing a schematic configuration of a hot wall type single wafer CVD apparatus according to a third embodiment.
FIG. 9 is a characteristic diagram showing an increase width of the substrate temperature with respect to the temperature of the heat insulating cylinder.
FIG. 10 is a characteristic diagram showing remanent polarization characteristics.
FIG. 11 is a diagram showing fatigue characteristics.
[Explanation of symbols]
101 ... Liquid raw material supply system
102 ... Reaction vessel
103 ... exhaust system
104 ... Liquid raw material container
105 ... Mixing manifold
106: Liquid flow controller
107 ... Vaporizer
108 ... Combustion chamber
109 ... Shower nozzle
110 ... Substrate to be deposited
111 ... susceptor
112 ... Heater
113 ... Mechanical booster pump
114 ... Dry vacuum pump

Claims (10)

A metal oxide thin film is formed on a deposition substrate by chemical vapor deposition using a gas obtained by vaporizing a solution in which a metal organic compound or a metal organic complex compound is dissolved in an organic solvent as a main source gas. In the method for forming a metal oxide thin film,
Before the source gas reaches the deposition target substrate, the source gas and an oxidant are mixed and preheated to decompose at least a part of the organic solvent in the gas. A method for forming a metal oxide thin film. 2. The method for forming a metal oxide thin film according to claim 1, wherein a noble metal film or a compound film containing a noble metal as a main component is present on at least a part of a surface layer of the deposition target substrate. The method for forming a metal oxide thin film according to claim 2, wherein the temperature of the preheating is 320 ° C. or higher. A vaporizer for generating a gas by vaporizing a solution of a metal organic compound or a metal organic complex compound dissolved in an organic solvent;
A combustion chamber that mixes the gas generated in the vaporizer and the oxidant, and decomposes at least a part of the organic solvent in the gas by a heating mechanism;
A film forming apparatus comprising: a reaction chamber in which a gas is supplied from the combustion chamber and a film is formed by a chemical vapor deposition method on a deposition target substrate disposed inside. A vaporizer for generating a gas by vaporizing a solution of a metal organic compound or a metal organic complex compound dissolved in an organic solvent;
A transport path for mixing the oxidant while transporting the gas generated in this vaporizer,
A heating mechanism for heating the transport path to decompose at least a part of the organic solvent in the gas in the transport path;
A gas in which at least a part of the organic solvent is decomposed by this heating mechanism is supplied, and a reaction chamber for forming a film by a chemical vapor deposition method is provided on a deposition target substrate installed inside. A film forming apparatus characterized by the above. 6. The film forming apparatus according to claim 5, wherein a heating furnace for heating the reaction chamber is used as the heating mechanism. The film forming apparatus according to claim 6, wherein the transport path is disposed in the reaction chamber. The film forming apparatus according to claim 7, wherein a gas obtained by decomposing at least a part of an organic solvent in the gas is directly supplied into the reaction chamber from the transport path. The film forming apparatus according to claim 7, wherein the transport path and the reaction chamber are made of quartz. The film forming apparatus according to claim 7, wherein the transport path has a folded portion.

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