JPS6114195A - Vertical gaseous phase growth device for thermally decomposing organometal - Google Patents

Abstract

PURPOSE:To grow a good-quality epitaxial crystal having uniformity throughout a large area with a simple structure by spouting a gaseous material radially and spirally from a specified introducing port into the reaction chamber of a vertical gaseous phase growth device for thermally decomposing an organometal. CONSTITUTION:A gaseous material is spouted from the introducing port 21 of a gaseous material introducing pipe 22 whose spouting direction diverges from the rotational axis of symmetry and which is inclined downward into the reaction chamber of a vertical gaseous phase growth device for thermally decomposing an organometal to cross the reaction chamber wall 23, and a violent spiral flow 24 is generated in the reaction chamber. The freshness of the gaseous material at the upper part of the reaction chamber is kept, and the sharpness of changes in composition and impurity concn. is ensured. The material is uniformly supplied onto the surface 25 of a substrate. Consequently, an epitaxial crystal having excellent uniformity in composition and film thickness is grown with good controllability and reproducibility.

Description

【発明の詳細な説明】 〔発明の属する技術分野〕 本発明は、有機金属熱分解法縦型気相成長装置において
、−切の可動部を有することなく反応室内へ渦流状に原
料気体を導入することにより成長するエピタキシャル層
の組成及び膜厚の均一性。[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a vertical vapor phase growth apparatus using an organometallic pyrolysis method, in which raw material gas is introduced into a reaction chamber in a swirling manner without having any moving parts. uniformity of the composition and thickness of the epitaxial layer grown by

制御性、界面における組成変化の急峻性、ならびに結晶
性の向上を目的とした反応室形状を改良した有機金属熱
分解縦型気相成長装置に関するものである。This invention relates to an organometallic pyrolysis vertical vapor phase growth apparatus in which the shape of the reaction chamber has been improved for the purpose of improving controllability, steepness of compositional changes at interfaces, and crystallinity.

〔従来技術と問題点〕[Conventional technology and problems]

有機金属熱分解気相成長法は、原理的に優れた組成比と
膜厚の制御性を有し、今後、重要性が増大すると思われ
る超高速素子、可視半導体レーザー用化合物半導体の成
長技術として注目されつつある。しかし、上記の原理的
に優れた特性を大面積の基板結晶にて実現し、半導体素
子の高性能化。Metal-organic pyrolysis vapor phase epitaxy has excellent composition ratio and film thickness controllability in principle, and is used as a growth technology for compound semiconductors for ultra-high-speed devices and visible semiconductor lasers, which are expected to become increasingly important in the future. It is gaining attention. However, by realizing the above-mentioned theoretically excellent characteristics using a large-area substrate crystal, the performance of semiconductor devices has been improved.

低価格化を計る場合、次のいくつかの問題点を生じる。When trying to lower prices, the following problems arise.

第１の問題としては、大面積を有する基板結晶表面への
均一な原料供給が困難になることであり、第２には、反
応室の大型化に伴ない反応室内における原料気体交換時
間の短縮化が困難となることにより接合界面での組成及
び不純物濃度分布の急峻性劣化が生じることである。中
でも、第３の熱対流の問題は有機金属熱分解法の結晶成
長機構に直接関連しており重大なものである。一般的に
、縦型有機金属熱分解気相成長法は、反応室内のカーボ
ンサセプター上の基板結晶を高周波誘導加熱装置によっ
て加熱し、上方より導入した各種原料の混合気体の基板
表面での熱分解により結晶成長を行うものである。しか
し、このような構造をもつ例えば第２図に示す様な反応
室で−は、導入管Ｉを通り導入口（２）より導入された
原料気体の流れ１騰は基板結晶Ｉに垂直に吹き付けられ
、基板結晶Ｉによる加熱との相乗効果により再び上昇し
、上方より供給される新鮮な混合気体の温度上昇を引き
起こす。すなわち、良好な結晶成長は原料気体の基板表
面のみにおける反応により達成されるが、激しい熱対流
による反応室内原料気体の加熱は、気相中での望ましく
ない反応を助長し、その結果、表面モホロジー、結晶性
の劣化を引き起こすすしかも、この効果は反応室形状、
基板温度により大きく影響をうけ、反応室、基板の大型
化に伴ない顕著になる傾向があるので特に重大である。The first problem is that it becomes difficult to uniformly supply raw materials to the substrate crystal surface, which has a large area, and the second problem is that the time for exchanging raw material gas in the reaction chamber is shortened as the reaction chamber becomes larger. As a result, the composition and impurity concentration distribution at the bonding interface become steeper. Among these, the third problem of thermal convection is directly related to the crystal growth mechanism of the organometallic pyrolysis method and is a serious one. Generally, in the vertical metal-organic pyrolysis vapor phase growth method, a substrate crystal on a carbon susceptor in a reaction chamber is heated by a high-frequency induction heating device, and a mixed gas of various raw materials introduced from above is pyrolyzed on the substrate surface. Crystal growth is performed by However, in a reaction chamber with such a structure, for example as shown in Figure 2, the flow of raw material gas introduced from the inlet (2) through the inlet pipe I is blown perpendicularly to the substrate crystal I. The temperature rises again due to the synergistic effect with the heating by the substrate crystal I, causing an increase in the temperature of the fresh mixed gas supplied from above. That is, although good crystal growth is achieved by the reaction of the raw material gas only on the substrate surface, heating of the raw material gas in the reaction chamber by intense thermal convection promotes undesirable reactions in the gas phase, resulting in changes in surface morphology. However, this effect is caused by the shape of the reaction chamber,
This is particularly important because it is greatly affected by the substrate temperature and tends to become more pronounced as the reaction chamber and substrate become larger.

従来、以上の諸問題の改善手段として、均一性向上９表
面モホロジー改善を目的とする反応室形状の工夫、拡散
板の採用、さらに積極的手段として基板への回転導入等
が試みられてきており一応の効果は認められているＯし
かし、これらの対策は明確な理論に裏付けられたもので
はなく、半経験的なものであり、しかも、原料気体の全
流量。In the past, attempts have been made to improve the above-mentioned problems by changing the shape of the reaction chamber to improve uniformity and improve surface morphology, using a diffusion plate, and, as a proactive measure, introducing rotation into the substrate. However, these measures are not backed by a clear theory and are semi-empirical, and furthermore, the total flow rate of the raw material gas has been confirmed to be effective.

基板温度等の成長条件に効果が大きく左右されることが
知られている。中でも、結晶性１表面モホロジーへの強
い影響が懸念される熱対流の問題については、有効な対
策は見い出されていなかった。It is known that the effect greatly depends on growth conditions such as substrate temperature. In particular, no effective countermeasures have been found for the problem of thermal convection, which is feared to have a strong influence on crystalline 1 surface morphology.

以上のごとく、有機金属熱分解法が、今後、高性能・低
価格半導体素子作製用の中心的結晶成長手段として確立
するために熱対流を含む諸問題のより積極的、かつ、根
本的解決法の確立が強く望まれていた。As described above, in order to establish the organometallic pyrolysis method as a central crystal growth method for the production of high-performance, low-cost semiconductor devices in the future, it is possible to find more proactive and fundamental solutions to various problems including thermal convection. There was a strong desire for the establishment of

〔発明の目的〕[Purpose of the invention]

本発明は、以上の様な従来装置の欠点を除き、比較的簡
単な構造で、良質かつ、大面積にわたり良好な均一性を
有するエピタキシャル結晶を再現よく成長可能な気相成
長装置を提供するものである０ 〔発明の概要〕 即ち、本発明は、縦型気相成長装置において渦流状に原
料気体を導入することを目的とした形状の導入口を備え
ることにより、反応室上部に強制。、□１〜つ、。〜、
１２ヤ７，２ワ　１゛長を実現するものである。The present invention eliminates the above-mentioned drawbacks of conventional devices and provides a vapor phase growth device that has a relatively simple structure, can grow epitaxial crystals of good quality and good uniformity over a large area with good reproducibility. 0 [Summary of the Invention] That is, the present invention provides a vertical vapor phase growth apparatus with an inlet having a shape intended to introduce a raw material gas in a vortex shape so that the raw material gas is forced into the upper part of the reaction chamber. ,□1~tsu,. ~,
It achieves a length of 12 years, 7 years, 2 years, and 1 inch.

〔発明の実施例〕[Embodiments of the invention]

以下、本発明の実施例を図面参照の上説明する０第１図
は、本発明に系る渦流状に原料気体を導入することを目
的とした原料導入口を有する反応室の上部を示すもので
ある０この反応室では、導入口−）が反応室の回転対称
軸から離れた場所に位置し、しかも、導入Ｉｒｌに）に
よって決定される噴出方向が斜め下方、かつ、回転対称
軸からはずれた方向、すなわち、反応室壁に）と斜めに
交差する方向であることを特徴としている。このような
反応室では、軸はずれの方向に激しく噴出した気流によ
り激しい渦流（財）が内部に発生する。このような、反
応室上部の渦流は、反応室内を隈なく吹きはらうことに
より、反応室上部の原料気体を常に新鮮に保ち、組成及
び不純物濃度変化の急峻性を確保し、同時に、基板表面
に）への均一な原料供給を実現する。又、従来、効果的
な対策が存在しなかった熱対流の問題についても、原料
気体の渦流による強制対流の発生が有効な対策となるこ
とは融液からの引き上げ成長法の例から容易に類推され
る。Hereinafter, embodiments of the present invention will be described with reference to the drawings.0 Figure 1 shows the upper part of a reaction chamber having a raw material inlet for the purpose of introducing raw material gas in a swirling manner according to the present invention. 0 In this reaction chamber, the inlet port -) is located at a location away from the axis of rotational symmetry of the reaction chamber, and the ejection direction determined by the inlet Irl) is diagonally downward and off the axis of rotational symmetry. It is characterized in that it is a direction diagonally intersecting the direction of the reaction chamber wall (i.e., the direction of the reaction chamber wall). In such a reaction chamber, a violent vortex is generated inside the reaction chamber due to the airflow violently ejected in an off-axis direction. The vortex flow at the top of the reaction chamber keeps the raw material gas at the top of the reaction chamber fresh by blowing it all over the inside of the reaction chamber, ensuring a steep change in composition and impurity concentration, and at the same time keeping the raw material gas at the top of the reaction chamber fresh. ) to achieve a uniform supply of raw materials. In addition, it can be easily inferred from the example of the pulling growth method from melt that the generation of forced convection by the vortex flow of the raw material gas is an effective countermeasure for the problem of thermal convection, for which there was no effective countermeasure in the past. be done.

〔発明の効果〕〔Effect of the invention〕

以Ｅを要約するに、本発明によれば、有機金属熱分解気
相成長法の優れた特性を大面積結晶基板にて実現し、半
導体素子の高性能化、低価格化を計る際のいくつかの問
題点が容ｉに解決可能であり、本−明は、今後の化合物
半導体素子の開発にとり、極めて重要なものである。In summary, according to the present invention, the excellent characteristics of the metal-organic pyrolysis vapor phase epitaxy method can be realized on a large-area crystal substrate, and several advantages can be achieved in improving the performance and lowering the cost of semiconductor devices. These problems can be easily solved, and the present invention is extremely important for the future development of compound semiconductor devices.

なお、本発明は２個以上の原料導入口を備えた反応室へ
も適用可能である。Note that the present invention is also applicable to a reaction chamber equipped with two or more raw material inlets.

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

第１図は本発明の一実施例に係る反応室上部の模式図、
第２図は従来使用されてきた縦型気相成長装置の反応室
上部の模式図である。 （１１）＃４・！−・・導入管、α紳ト・・・・・導入
口。 α■←・・・・・導入された原料気体の流れ。 ａ４に）・・・・・・グラファイトサセプタ上の基板結
晶。 ａＩト・・・・・反ろ管理。 代理人　弁理士　則　近　憲　佑 （ほか１名） 第１図 第２図 一ζζへ−FIG. 1 is a schematic diagram of the upper part of the reaction chamber according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the upper part of the reaction chamber of a conventionally used vertical vapor phase growth apparatus. (11) #4・! −・・Introduction pipe, α shaft・・・Introduction port. α■←・・・Flow of introduced raw material gas. a4)...Substrate crystal on graphite susceptor. aI to... reverse management. Agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 1 ζζ

Claims (1)

【特許請求の範囲】[Claims] 　渦流状に原料気体を導入することを目的とした形状の
導入口を有することを特徴とする反応室を備えた有機金
属熱分解縦型気相成長装置。A vertical vapor phase growth apparatus for organometallic pyrolysis comprising a reaction chamber characterized by having an inlet shaped to introduce a raw material gas in a swirling manner.