JPS6190436A - Chemical vapor growth apparatus - Google Patents

Abstract

PURPOSE:To contrive to make the film quality and film thickness in a hybrid film uniform by a method wherein the side wall of a partial tube is provided with a plurality of gas spouts at the part facing a supporting plate, and the tip side spout is positioned on the side of rotation outer periphery of the supporting plate, and the gas inlet side spout on the side of rotation center. CONSTITUTION:A substrate 6 is rotated around the first gas introduction tube 2 by rotating a rotary quartz plate 1 provided with the substrate 6. Silane and dimethyl zinc or diethyl zinc, raw material gases, mix with each other on the rotary plate 1, and a hybrid film of ZnO an SiO2 if formed on the substrate 6 through thermal decomposition and oxidation. The tip 3-3 of the second gas introduction tube 3 through which the raw material gas is introduced is located in the outer periphery 1-2 of the rotary plate 1, and a plurality of gas spouts 3-2 are provided in a part 3-4 extending from the tip 3-3 of a part 3-1 parallel with the supporting plate 1 to the root at the position 3-5 corresponding to the section from the outer periphery 1-2 of the rotary plate 1 to its center 1-1. Therefore, spout sections of larger amount of flow have larger areas of ZnO growth, whereas those of smaller amount of flow have smaller area of the growth; accordingly, the ratio of ZnO to SiO2 in the hybrid film can be made uniform.

Description

Translated fromJapanese

【発明の詳細な説明】（産業上の利用分野）本発明は薄膜特に混成膜の気相成長装置に関する。[Detailed description of the invention](Industrial application field)The present invention relates to a vapor phase growth apparatus for thin films, particularly hybrid films.

（従来の技術）薄膜の気相成長装置では例えば日本学術振興会編「薄膜
ハンドブック」（昭５８．１２．１０　）オーム社Ｐ２
１５図４．２２で示されているように一般に１系統のが
ス導入管を備えているが、Ｚｎ０Ｉ！：５ｉ０２との混
成膜のように比較的機しい反応を伴なう場合には、第２
図に示すように、２系統のガス導入管を備え装置が有用
であ・す、このことを本発明者らは実願昭５８−０７１
１４６号出願によって提案した。(Prior art) For thin film vapor phase growth equipment, for example, "Thin Film Handbook" edited by the Japan Society for the Promotion of Science (December 10, 1980) Ohmsha P2
15 As shown in Figure 4.22, one system of gas inlet pipe is generally provided, but Zn0I! : In cases where a relatively favorable reaction is involved, such as a hybrid film with 5i02, the second
As shown in the figure, a device equipped with two systems of gas introduction pipes is useful.
It was proposed by Application No. 146.

第２図において、１は回転石英板、２は第１．ガス導入
管、３は第２ガス導入管、４は石英板、５はヒータ、６
は回転石英板１上に載置された基板、７は回転石英板１
０回転方向を示している。In FIG. 2, 1 is a rotating quartz plate, 2 is a first . Gas introduction pipe, 3 is a second gas introduction pipe, 4 is a quartz plate, 5 is a heater, 6
7 is the substrate placed on the rotating quartz plate 1, and 7 is the rotating quartz plate 1.
The direction of 0 rotation is shown.

ガス導入の径路は図示していないが、第１ガス導入管２
の噴出孔２−２より、原料ガスとして、酸素、シラン及
び輸送ガスとしてアルゴン又は窒素を反応室へ導入し、
第２ガス導入管３ａの噴出孔３＆−２よシ原料ガスとし
てジメチル亜鉛又はジエチル亜鉛及び輸送ガスとして同
じょうにアルがン又は窒素を回転石英板１の上面に直接
あたるように反応室へ噴出する。原料ガスのシラン、ツ
メチル亜鉛又はジエチル亜鉛は回転石英板１上で混合し
、熱分解し、酸化し、回転石英板ｌの上におかれた基板
６上にＺｎＯとＳ　ｒ　Ｏ２の混成膜が形成される。回
転石英板１は矢印７の方向に回転させであるので基板６
は第１ガス導入管２を中心として公転する。このように
して酸素とシランとの反応に比べて、酸素との反応が激
しいジメチル亜鉛又はジエチル亜鉛を酸素とちがった第
２ガス導入ＶＳａで反応室内に導入し、直接基板６にあ
たるように噴出するから、形成されるＺｎＯと５Ｉ０２
との混成膜内のＺｎＯとＳ　＋　０２の混成比を自由に
変化させることができ、安定なＺｎＯとＳ　ｒ　０２と
の混成膜が得られる。Although the gas introduction path is not shown, the first gas introduction pipe 2
Introducing oxygen, silane as a raw material gas, and argon or nitrogen as a transport gas into the reaction chamber from the nozzle 2-2,
Through the ejection holes 3 & -2 of the second gas introduction pipe 3a, dimethylzinc or diethylzinc as a raw material gas and arganese or nitrogen as a transport gas are ejected into the reaction chamber so as to directly hit the upper surface of the rotating quartz plate 1. do. The raw material gases silane, trimethylzinc or diethylzinc are mixed on a rotating quartz plate 1, thermally decomposed and oxidized, and a composite film of ZnO and SrO2 is formed on a substrate 6 placed on the rotating quartz plate 1. It is formed. Since the rotating quartz plate 1 is rotated in the direction of the arrow 7, the substrate 6
revolves around the first gas introduction pipe 2. In this way, dimethylzinc or diethylzinc, which reacts more strongly with oxygen than the reaction between oxygen and silane, is introduced into the reaction chamber by the second gas introduction VSa, which is different from oxygen, and is ejected so as to directly hit the substrate 6. From, ZnO and 5I02 are formed.
The mixture ratio of ZnO and S + 02 in the hybrid film can be freely changed, and a stable hybrid film of ZnO and S r 02 can be obtained.

（発明が解決しようとする問題点）しかし原料ガスとしてのジメチル亜鉛又はジエチル亜鉛
は酸素との反応がはげしいので、第２ガス導入管３の噴
出口３ａ−２から噴出される原料ガスが方接基板回転石
英板１上におかれた基板６にあたった部分にほとんど成
長し、この原料がスの流速により、ＺｎＯとＳ　ｒ　０
２の混成比に大きく依存し、安定な混成膜を得るために
は、との原料ガスの流速を大きくする必要がある。この
ため、輸送ガスのアルゴン又は窒素の流量を犬きぐする
必要となシ、第２ガス導入管３ａの噴出孔３ａ−２から
噴出するガス流量は、第３図に示すように先端部３ａ−
３の噴出孔から噴出するガス流量が大きくなっていて、
このため、基板６上に形成されるＺｎＯとＳ　ｒ　０２
の混成膜中のＺｎＯとＳｉＯ□との混成比は、第４図に
示すように、回転石英板の回転の中心はどＺｎＯのしめ
る割合が大きく々シ分布が不均一となシ、形成される混
成膜の膜質膜厚の分布が不均一となる欠点があった。(Problem to be Solved by the Invention) However, since dimethylzinc or diethylzinc as a raw material gas reacts violently with oxygen, the raw material gas ejected from the spout 3a-2 of the second gas introduction pipe 3 is Most of the growth occurs on the part that hits the substrate 6 placed on the substrate rotating quartz plate 1, and due to the flow rate of this raw material, ZnO and S r 0
In order to obtain a stable hybrid film, it is necessary to increase the flow rate of the raw material gas. Therefore, it is not necessary to carefully control the flow rate of the transport gas argon or nitrogen, and the flow rate of the gas ejected from the ejection hole 3a-2 of the second gas introduction pipe 3a is adjusted as shown in FIG.
The gas flow rate ejected from the nozzle no. 3 is increasing,
Therefore, ZnO and S r 02 formed on the substrate 6
The mixture ratio of ZnO and SiO However, there is a drawback that the distribution of film quality and thickness of the hybrid film becomes non-uniform.

第２図は、第２ガス導入管３の回転石英板ｌと平行な部
分３−１の複数の噴出孔３−２の各噴出孔よシ噴出され
るガス流量を表わすグラフであり、横軸には、第２ガス
導入管３ａの平行な部分３ａ−１の先端３ａ−３から導
入口側根元３ａ−４への距離Ｘを示し、縦軸は各噴出孔
より噴出されるガス流量ｆを示すもので、先端３ａ−３
、すなわち回転石英板の回転の中心はどガス流量が多く
、周辺になるほど少なくなる傾向を表わしている。第４
図は、基板上に形成されるＺｎＯと５ｉ０２の混成膜中
にしめる回転石英板の回転の半径方向のＺｎＯの分布を
示すグラフであシ、横軸は、基板回転石英板ｌの回、転
中心の近傍からの半径方向距離ｙであり縦軸はＺｎＯと
５ｔＯ２の混成膜中に占めるＺｎＯの割合Ｎを示してい
るが、図からｚｒＩＯの割合が距離により変化する傾向
を示すことがわかる。FIG. 2 is a graph showing the gas flow rate ejected from each of the plurality of ejection holes 3-2 in the portion 3-1 parallel to the rotating quartz plate l of the second gas introduction pipe 3, and the horizontal axis shows the distance X from the tip 3a-3 of the parallel portion 3a-1 of the second gas introduction pipe 3a to the inlet side root 3a-4, and the vertical axis represents the gas flow rate f ejected from each ejection hole. As shown, the tip 3a-3
That is, the gas flow rate tends to be large at the center of rotation of the rotating quartz plate, and decrease toward the periphery. Fourth
The figure is a graph showing the distribution of ZnO in the radial direction of rotation of a rotated quartz plate, which is contained in a composite film of ZnO and 5i02 formed on a substrate.The horizontal axis is the center of rotation of the rotated quartz plate l. The vertical axis indicates the radial distance y from the vicinity of , and the vertical axis indicates the proportion N of ZnO in the composite film of ZnO and 5tO2, and it can be seen from the figure that the proportion of zrIO tends to change depending on the distance.

この発明は以上のべた、混成膜の膜質、膜厚分布の不均
一となる欠点を除去し、混成膜内の膜質、膜厚分布の均
一性の優れた装置を提供することを目的とする。It is an object of the present invention to eliminate the above-mentioned drawbacks of non-uniform film quality and film thickness distribution of a hybrid film, and to provide an apparatus with excellent uniformity of film quality and film thickness distribution within the hybrid film.

（問題点を解決するための手段）この発明は、ジメチル亜鉛やジエチル亜鉛などの第２ガ
スを導入する第２ガス導入管において、石英板などの支
持板などの支持板と水平に配置した部分管を設け、その
側壁の支持板に面した部分に複数の噴出口を設け、先端
側の噴出口を支持板の回転外周側に位置づけ、且つガス
導入口側の噴出口を支持板の回転中心側に位置づけたも
のである。(Means for Solving the Problems) This invention provides a second gas introduction pipe for introducing a second gas such as dimethylzinc or diethylzinc, in which a portion is disposed horizontally with a support plate such as a support plate such as a quartz plate. A pipe is provided, and a plurality of jet ports are provided on the side wall facing the support plate, and the jet port on the tip side is positioned on the rotational outer circumferential side of the support plate, and the jet port on the gas inlet side is located at the center of rotation of the support plate. It is positioned on the side.

（作用）このような構成によって、例えばＺｎＯ成分を成長させ
るべき面積が大きい外周はどガス流量が多くなシ、成長
させるべき面積が小さいほどガス流量が少なくなり、例
えばＺｎＯとＳｉＯ□との混合比が均一に分布するとと
Ｘなる。(Function) With such a configuration, for example, the gas flow rate is high at the outer periphery where the area where the ZnO component is to be grown is large, and the gas flow rate is low as the area where the ZnO component is to be grown is small. If the ratio is uniformly distributed, then it becomes X.

（実施例）第１図は、この発明の実施例を示す斜視図であって、装
置の主要部を説明するために一部を切断しである。第２
図と同一部分には、同一符合を付しである。第１図にお
いて、１は回転石英板、２は第１ガス導入管、３は第２
ガス導入管、４は石英板、５はヒータ、６は回転石英板
１上に載置された基板、２は回転石英板Ｊの回転方向を
示している。(Embodiment) FIG. 1 is a perspective view showing an embodiment of the present invention, with a portion cut away to explain the main parts of the device. Second
The same parts as in the figures are given the same reference numerals. In Fig. 1, 1 is a rotating quartz plate, 2 is a first gas introduction pipe, and 3 is a second gas introduction pipe.
4 is a quartz plate, 5 is a heater, 6 is a substrate placed on the rotating quartz plate 1, and 2 is the direction of rotation of the rotating quartz plate J.

第２図に示した従来のＺｎＯとＳ＋０２の混成膜を形成
する化学気相成長装置と同様に、回転石英板ｌ上に基板
６をおき、回転石英板１を矢印２方向に回転させて、第
１ガス導入管２を中心に基板６を回転させる。中央部に
ある第１ガス導入管２より原料ガスとしての酸素、ンラ
ン及び輸送ガスとしてアルゴン又は窒素を導入し、第２
ガス導入管３より原料ガスとしてのツメチル亜鉛又はジ
エチル亜鉛及び輸送ガスとして同様にアルゴン又は窒素
を回転石英板１に直接あたるように噴出する。原料ガス
のンラン及びツメチル亜鉛又はジエチル亜鉛は、回転石
英板１上で混合し、熱分解し、酸化し、回転石英板Ｊ上
におかれた基板６上１ｃＺｎｏとＳ　ｒ　０２の混成膜
が形成される。第２ガス導入管３は回転石英板１と平行
に配置されその外周より中心に向って配置された平行部
３−１を有し、第２ガス導入管３の先端部３−３が回転
石英板ｌの外周部１−２に位置し、第２ガス導入管３の
ガス噴出口３−２は平行部３−１の先端部３−３より根
元部３−４に至たる部分で回転石英板１の外周部１−２
から中心部ノーＩＫあたる部分３−５に対応して設けら
れている。Similar to the conventional chemical vapor deposition apparatus for forming a ZnO and S+02 hybrid film shown in FIG. The substrate 6 is rotated around the first gas introduction pipe 2. Oxygen and nitrogen as raw material gases and argon or nitrogen as transport gas are introduced from the first gas introduction pipe 2 located in the center, and the second
From the gas introduction pipe 3, dimethylzinc or diethylzinc as a raw material gas and argon or nitrogen as a transport gas are ejected so as to directly hit the rotating quartz plate 1. The raw material gas Nran and methylzinc or diethylzinc are mixed on the rotating quartz plate 1, thermally decomposed and oxidized, and a hybrid film of 1cZno and Sr02 is formed on the substrate 6 placed on the rotating quartz plate J. be done. The second gas introduction pipe 3 is arranged parallel to the rotating quartz plate 1 and has a parallel part 3-1 arranged from the outer periphery toward the center. The gas outlet 3-2 of the second gas introduction pipe 3 is located on the outer circumference 1-2 of the plate 1, and the gas outlet 3-2 of the parallel portion 3-1 is made of rotary quartz at a portion from the tip 3-3 to the root 3-4. Outer periphery 1-2 of plate 1
It is provided corresponding to the part 3-5 corresponding to the center part No IK.

原料ガスであるジエチル亜鉛及びツメチル亜鉛の第２ガ
ス導入管３の噴出孔３−２から噴出されるガス流量は従
来と同様に第３図に示すように先端部３−３の方になる
ほど大きく々る。本実施例では、第２ガス導入管３の先
端３−３が基板回転板の外周部１−２に位置しているた
め、基板回転石英板の外周部１−２はどガス流量が多く
、中心部１−１になるほど少なくなる傾向を表わしてい
る。回転石英板２の中心部１−１の円周が外周部１−２
の円周にくらべて小さく、ガス流量が多い部分では、Ｚ
ｎＯを成長する部分の面積が犬きくなり、ガス流量の少
ない部分ではり０を成長する部分の面積が小さくなる結
果、基板６上に形成されるＺｎＯと８１０２の混成膜中
のＺｎＯと５ＩＯ２との混成比は、第５図に示すように
分布を均一にすることができる。As in the conventional case, the gas flow rate of the raw material gases diethylzinc and dimethylzinc ejected from the ejection hole 3-2 of the second gas introduction pipe 3 increases toward the tip 3-3 as shown in FIG. That's it. In this embodiment, since the tip 3-3 of the second gas introduction pipe 3 is located at the outer circumferential portion 1-2 of the substrate rotating quartz plate, the gas flow rate is large at the outer circumferential portion 1-2 of the substrate rotating quartz plate. This shows a tendency for the number to decrease toward the center 1-1. The circumference of the center 1-1 of the rotating quartz plate 2 is the outer periphery 1-2.
In areas where the gas flow rate is large and is small compared to the circumference of
As a result, the area of the part where nO is grown becomes smaller, and the area of the part where beam 0 is grown becomes smaller in the part where the gas flow rate is low. The mixing ratio of can make the distribution uniform as shown in FIG.

第５図は基板６上に形成されるＺ−ｎｏとＳｉＯの混成
膜中にしめる半径方向のＺｎＯの分布を示すグラフであ
る。横軸は回転石英板１の中心を基準点として、半径方
向すなわち第４図に示すｙの方向の　　　　　　・１き
ょシｙを示し、縦軸はＺｎＯとＳ　ｉＯ２の混成膜中に
占めるＺｎＯの割合Ｎを示す。ＺｎＯとＳ＋０２の混成
膜中のＺｎＯの占める分布は均一となる。FIG. 5 is a graph showing the distribution of ZnO in the radial direction in the composite film of Z-no and SiO formed on the substrate 6. As shown in FIG. The horizontal axis shows the radial direction, that is, the direction of y shown in FIG. The ratio N is shown. The distribution of ZnO in the composite film of ZnO and S+02 becomes uniform.

（発明の効果）以上詳細に説明したように本発明によれば、例えばＺｎ
ＯとＳ　ＩＯ２との混成膜を形成する化学気相成長装置
において、原料ガスである例えばツメチル亜鉛又はジエ
チル亜鉛を導入する第２ガス導入管の先端部が回転支持
板の外周部に位置し、第２のガス導入管のガス噴出口は
第２ガス導入管が回転支持板と平行部で先端部より根元
に至たる部分で基板回転石英板の外周部から中心部にあ
たる位置に複数個設けられたのでガス流量が多い噴出孔
の部分はどこの噴出孔からでる原料ガスが直接あたる。(Effects of the Invention) As explained in detail above, according to the present invention, for example, Zn
In a chemical vapor deposition apparatus for forming a hybrid film of O and SIO2, the tip of a second gas introduction pipe for introducing a raw material gas such as dimethylzinc or diethylzinc is located at the outer periphery of the rotating support plate, A plurality of gas ejection ports of the second gas introduction pipe are provided at positions where the second gas introduction pipe is parallel to the rotating support plate and extends from the tip to the root, from the outer periphery to the center of the substrate rotating quartz plate. Therefore, the part of the nozzle where the gas flow rate is high is directly hit by the source gas coming out of any nozzle.

この噴出孔によりＺｎＯを成長させる部分の面積が犬き
くなり、ガス流量が少ない噴出孔の部分はど面積が小さ
くなるという、ガス流量と成長する面積が比例関係とな
っているため、基板上に形成されるＺｎＯと５１０２の
混成膜中のＺｎＯとＳ　ｒ　０２の混成比を均一にする
ことが期待できる。Because of the proportional relationship between the gas flow rate and the area where ZnO grows, the area of the part where ZnO is grown becomes smaller due to the nozzle, and the area of the nozzle where the gas flow rate is low is small. It can be expected that the mixture ratio of ZnO and S r 02 in the formed composite film of ZnO and 5102 can be made uniform.

又例えばＺｎＯとＳ　ｉ　Ｏ２の混成膜中のＺｒ、０と
Ｓ　ｉ　Ｏ２の割合が膜厚白物−にできる利点がある−
のでこの混成膜を拡散源とするＺｎ拡散に本発明による
ものを利用することができるという効果がある。Also, for example, there is an advantage that the ratio of Zr, 0 and SiO2 in a composite film of ZnO and SiO2 can be adjusted to a uniform film thickness.
Therefore, the present invention has the advantage that it can be used for Zn diffusion using this composite film as a diffusion source.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の１実施例を示す一部切断斜視図、第２
図は従来の装置を説明する一部切断斜視図、第３図は第
２ガス導入管から噴出されるガス量の傾向を示すグラフ
、第４図は従来の装置での成長する混成膜中のＺｎｏＯ
分布グラフ、第５図は本発明の実施例で成長する混成膜
中のＺｎＯの分布グラフ。Ｉ・・回転石英板、２・・・第１ガス導入管、３・・・
第２ガス導入管、４・・石英板、５・・・ヒータ、６・
・・基板、７・・・回転方向を示す矢印。特許出願人　沖電気工業株式会社第１図第２図第３図第４図ＯＶ　　ｙ；ｐ＋、ｙｆｆｓ＊’、よ１）第５図ｙ１、事件の表示昭和５９年　特　許　願第２１１４８８号２、発明の名
称化学気相成長装置３、補正をする者事件との関係　　　　　　特　許　出　願　人住　所（
〒１０５）　　東京都港区虎ノ門１丁目７番１２号５、
補正の対象　明細書中「発明の詳細な説明」の欄６、補
正の内容（１）　　明細書第２頁第７行に「反応を伴なう」とあ
るのを「反応速度の差を伴う」と補正する。（２）　　同書第４頁第１４行目に「第２図は、」とあ
るのを「第３図は、」と補正する。（３）　　同書第５頁第１７行目に「石英板などの支持
板などの支持板」とあるのを「石英板などの支持板」と補正する。（４）同書第９頁第１３行及び第１４行に「部分はどこ
の噴出孔からでる原料ガスが直接あたる。この噴出孔に
よりＺｎＯを成長させる」とあるのを「部分はどこの噴出孔からでる原料ガスが直接あたり、
ＺｎＯを成長させる」と補正する。以上FIG. 1 is a partially cutaway perspective view showing one embodiment of the present invention, and FIG.
The figure is a partially cutaway perspective view explaining the conventional device, FIG. 3 is a graph showing the tendency of the amount of gas ejected from the second gas introduction pipe, and FIG. ZnoO
Distribution graph: FIG. 5 is a distribution graph of ZnO in a composite film grown in an example of the present invention. I... Rotating quartz plate, 2... First gas introduction pipe, 3...
2nd gas introduction pipe, 4...quartz plate, 5... heater, 6...
... Board, 7... Arrow indicating the direction of rotation. Patent Applicant: Oki Electric Industry Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 OV y;p+,yffs*', 1) Figure 5 y 1. Indication of the incident 1982 Patent Application No. 211488 2. Name of the invention Chemical vapor deposition device 3. Relationship with the case of the person making the amendment Patent application Person's address (
105) 1-7-12-5 Toranomon, Minato-ku, Tokyo.
Subject of amendment Column 6 of “Detailed Description of the Invention” in the specification, contents of amendment (1) In the 7th line of page 2 of the specification, the phrase “accompanied by a reaction” was replaced with “accompanied by a difference in reaction rate.” ” he corrected. (2) On page 4, line 14 of the same book, the phrase ``Figure 2 is'' has been amended to ``Figure 3 is''. (3) On page 5, line 17 of the same book, the phrase "support plate such as a quartz plate" is amended to read "support plate such as a quartz plate." (4) On page 9, lines 13 and 14 of the same book, it says, "The part is directly hit by the raw material gas coming out of which nozzle. ZnO is grown by this nozzle." The raw material gas coming out of the
"Grow ZnO". that's all

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]　薄膜を成長させるべき基板が搭載されるものであって
回転可能な支持板と、当該支持板の中心部で当該支持板
とほぼ垂直に配置された部分管を有し且つ第１ガスを反
応室へ導入する複数の噴出口を当該部分管の側壁に備え
た第１ガス導入管と、前記支持板とほぼ水平に配置され
た部分管を有し且つ第２ガスを前記反応室へ導入する複
数の噴出口を当該部分管の側壁に備えた第２ガス導入管
とを含む気相成長装置において、前記第２ガス導入管の
ガス導入側の噴出口を、前記支持板の回転中心側に位置
づけ、且つ前記第２ガス導入管の先端側の噴出口を、前
記支持板の回転外周側に位置づけてあることを特徴とし
た気相成長装置。The device has a rotatable support plate on which a substrate on which a thin film is to be grown, and a partial tube arranged substantially perpendicular to the support plate at the center of the support plate, and supplies a first gas to a reaction chamber. a first gas introduction pipe having a plurality of jet ports on the side wall of the partial pipe for introducing the gas into the reaction chamber; In a vapor phase growth apparatus including a second gas introduction pipe having an ejection port on a side wall of the partial tube, the ejection port on the gas introduction side of the second gas introduction pipe is positioned on the rotation center side of the support plate. , and a vapor phase growth apparatus characterized in that the ejection port on the tip side of the second gas introduction pipe is positioned on the rotational outer peripheral side of the support plate.