JP2005298253A

JP2005298253A - Manufacturing method of compound semiconductor single crystal

Info

Publication number: JP2005298253A
Application number: JP2004115439A
Authority: JP
Inventors: Shinji Yabuki; 伸司矢吹; Michinori Wachi; 三千則和地; Takuji Nagayama; 卓司長山
Original assignee: Hitachi Cable Ltd
Current assignee: Hitachi Cable Ltd
Priority date: 2004-04-09
Filing date: 2004-04-09
Publication date: 2005-10-27

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a compound semiconductor single crystal through an LEC method, whereby polycrystallization caused by concave shaping of a solid-liquid interface can be prevented and yield of the single crystal can be improved over the entire range, by placing baffles in a liquid sealant in a crucible in a posture effective for stirring. <P>SOLUTION: In the crucible 5 serving as a raw material container, the baffles 11 intended for stirring the liquid sealant are placed in the liquid sealant 6 in appropriate angles of inclination (installation angles of inclination θ) for stirring to prevent polycrystallization of the crystal. The installation angles of inclination θ are acute angles, preferably 30-60°, when each baffle plate 11 is slanted by rotating in a direction opposite to the direction of rotation of the crucible 5. From two to four baffles 11 are placed at even intervals in a circumferential direction, i.e. around the crystal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、液体封止チョクラルスキー法（ＬＥＣ法）を用いた化合物半導体単結晶の製造方法に係り、特に半絶縁性ＧａＡｓ単結晶の製造方法に好適なものに関する。 The present invention relates to a method for manufacturing a compound semiconductor single crystal using a liquid-sealed Czochralski method (LEC method), and particularly to a method suitable for a method for manufacturing a semi-insulating GaAs single crystal.

ＬＥＣ法によるＧａＡｓ単結晶の製造方法を図４によって説明する。 A method for producing a GaAs single crystal by the LEC method will be described with reference to FIG.

ＬＥＣ法によるＧａＡｓ単結晶製造装置１は、炉体部分（耐圧容器）であるチャンバー２と、結晶を引き上げる為の引上軸３と、原料の容器であるＰＢＮルツボ５と、このルツボを受ける為のルツボ軸４を有する構造となっている。 The GaAs single crystal manufacturing apparatus 1 by the LEC method receives a chamber 2 which is a furnace body part (pressure vessel), a pulling shaft 3 for pulling up a crystal, a PBN crucible 5 which is a raw material container, and the crucible. It has a structure having a crucible shaft 4.

結晶製造方法については、先ず原料の容器となるＰＢＮルツボ５に原料としてのＧａとＡｓ及びＡｓの揮発を防止するための三酸化硼素６を入れ、これをチャンバー２内にセットする。又、引上軸３の先端に結晶の元となる種結晶７を取り付ける。この種結晶７はＧａＡｓ融液と接する面を（１００）面としているのが一般的である。 Regarding the crystal manufacturing method, first, Ga, As, and boron trioxide 6 for preventing volatilization of As and As are introduced into a PBN crucible 5 serving as a material container, and this is set in the chamber 2. Further, a seed crystal 7 as a crystal base is attached to the tip of the pull-up shaft 3. In general, the seed crystal 7 has a (100) plane in contact with the GaAs melt.

チャンバー２に原料をセットした後、チャンバー２内を真空にし、不活性ガスを充填する。その後、チャンバー２内に設置してある抵抗加熱ヒータ８に通電し、チャンバー２内の温度を昇温させ、ＧａとＡｓを合成しＧａＡｓを作製する。その後、更に昇温させＧａＡｓを融液化させ、ＧａＡｓ融液９を作成する。 After setting the raw material in the chamber 2, the inside of the chamber 2 is evacuated and filled with an inert gas. Thereafter, the resistance heater 8 installed in the chamber 2 is energized, the temperature in the chamber 2 is increased, and Ga and As are synthesized to produce GaAs. Thereafter, the temperature is further raised to melt GaAs, and a GaAs melt 9 is prepared.

続いて、引上軸３、ルツボ軸４を回転方向が逆になるように回転させる。この状態で、引上軸３を先端に取り付けてある種結晶７がＧａＡｓ融液９に接触するまで下降させる。 Subsequently, the pull-up shaft 3 and the crucible shaft 4 are rotated so that the rotation directions are reversed. In this state, the pull-up shaft 3 is lowered until the seed crystal 7 attached to the tip contacts the GaAs melt 9.

続いて、抵抗加熱ヒータ８の設定温度を徐々に下げつつ引上軸３を一定の速度で上昇させることで、種結晶７から徐々に結晶径を太らせながら結晶肩部を形成する。肩部形成後、目標とする結晶外径となったならば、外径を一定に保つ為、外径を制御しつつＧａＡｓ単結晶１０の製造を行う。 Subsequently, by raising the pulling shaft 3 at a constant speed while gradually lowering the set temperature of the resistance heater 8, a crystal shoulder is formed while gradually increasing the crystal diameter from the seed crystal 7. If the target crystal outer diameter is reached after the shoulder formation, the GaAs single crystal 10 is manufactured while controlling the outer diameter in order to keep the outer diameter constant.

上記ＧａＡｓの単結晶を成長する場合、結晶が有転位結晶であるため転位集合防止のために、その固液界面形状は融液側に凸となる形状で行うのが一般的である。 When growing the GaAs single crystal, since the crystal is a dislocation crystal, in order to prevent dislocation aggregation, the shape of the solid-liquid interface is generally a convex shape on the melt side.

ところで、上記のＬＥＣ法によってＧａＡｓ単結晶の成長に際しては、結晶が多結晶化するのを防止して単結晶部分をできるだけ長くすることが好ましい。単結晶部分が長ければ、１本の材料からより多くのウェハをスライスすることができ、また引上げ炉の準備時間と準備回数を削減でき、さらには特性評価の回数も減らすことができる。また、引き上げに用いる消耗品（ルツボ、封止剤）費用の原価に対する割合を下げることができる。 By the way, when a GaAs single crystal is grown by the above LEC method, it is preferable to prevent the crystal from being polycrystallized and make the single crystal portion as long as possible. If the single crystal portion is long, more wafers can be sliced from one material, the preparation time and the number of preparations of the pulling furnace can be reduced, and the number of characterizations can be reduced. Moreover, the ratio with respect to the cost of the consumables (crucible, sealing agent) cost used for raising can be lowered.

上記の多結晶化の原因は主として２つあり、一つは固液界面形状が凹凸になり、その部分に熱応力が集中して転位が発生して起こるものであり、他の一つは結晶の表面荒れ、つまり結晶表面が輻射熱を受けて高温となり、Ａｓが解離して残されたＧａが表面を伝わって固液界面に達して起こるものである。 There are mainly two causes of the above-mentioned polycrystallization. One is that the solid-liquid interface shape is uneven, and thermal stress concentrates on that part, resulting in dislocations. The other is crystal Surface roughness of the crystal, that is, the crystal surface is heated to a high temperature due to radiant heat, and Ga left after dissociating As reaches the solid-liquid interface through the surface.

前者の原因の解消策としては、ヒータの発熱量の制御、ヒータやホットゾーンの形状等を改良する試みがなされており、また、後者の原因の解消策としては、単結晶の周りに筒や板を設けて輻射熱を遮ったり、筒や板或いは単結晶にガスを吹き付けることが試みられている。 As a solution for the former cause, attempts have been made to improve the control of the amount of heat generated by the heater, the shape of the heater and hot zone, etc. Attempts have been made to shield the radiant heat by providing a plate or to blow a gas onto a cylinder, plate or single crystal.

なお、固液界面形状の凹面化防止技術の見地から直接に論じられたものではないが、特開２０００−２８１５００号公報（特許文献１）には、２つの邪魔板で封止剤融液を攪拌することにより、炉内の雰囲気ガスと原料融液との間接的な接触頻度を高め、ＧａＡｓ単結晶中の炭素濃度として、高炭素濃度が要求される場合であっても、原料融液中の炭素濃度を目標値に設定するまでの時間を短縮することが開示されている。
特開２０００−２８１５００号公報（図５） Although not discussed directly from the standpoint of the technology for preventing the formation of a concave-convex solid-liquid interface shape, Japanese Patent Application Laid-Open No. 2000-281500 (Patent Document 1) discloses a sealant melt with two baffle plates. By stirring, the frequency of indirect contact between the atmospheric gas in the furnace and the raw material melt is increased, and even if a high carbon concentration is required as the carbon concentration in the GaAs single crystal, It is disclosed that the time required to set the carbon concentration of the target to the target value is shortened.
JP 2000-281500 A (FIG. 5)

上記のように、図４のＧａＡｓ単結晶成長における問題点の一つとして、転位の集合による結晶の多結晶化という問題がある。転位は結晶と融液の境界面である固液界面に垂直に伝播する性質があり、固液界面が融液側に凹面形状をしていると転位の集合が起こってしまう。よって、転位の集合を防止する為には、固液界面の形状を結晶成長中に常に融液側に凸となるように制御する必要がある。又、固液界面は熱流に対して垂直に形成される。よって、固液界面を凸化させるには、結晶の冷却を促進させ、熱の流れを固液界面→結晶中央部→結晶上部→結晶外部という流れにすれば良いことになる。 As described above, as one of the problems in the GaAs single crystal growth of FIG. 4, there is a problem that the crystal is polycrystallized due to dislocation aggregation. Dislocations have the property of propagating perpendicularly to the solid-liquid interface, which is the interface between the crystal and the melt. If the solid-liquid interface has a concave shape on the melt side, the dislocations are aggregated. Therefore, in order to prevent dislocation aggregation, it is necessary to control the shape of the solid-liquid interface so that it always protrudes toward the melt side during crystal growth. The solid-liquid interface is formed perpendicular to the heat flow. Therefore, in order to make the solid-liquid interface convex, it is sufficient to promote cooling of the crystal and change the flow of heat from the solid-liquid interface → the center of the crystal → the top of the crystal → the outside of the crystal.

しかしながら、本発明者等の知見によれば、従来技術の場合、結晶エッジ部付近において、液体封止剤の相対温度が結晶より低いことが原因で、熱流が固液界面→結晶側面→液体封止剤という流れが発生し、これにより結晶エッジ部付近の固液界面形状が凹面化し、強いては転位集合による結晶の多結晶が発生する。液体封止剤の相対温度が結晶より低くなる理由として、通常、液体封止剤の材料としては三酸化硼素を用いるのが一般的であるが、三酸化硼素の特徴として熱伝導率が低い、粘性が高いがため熱伝達も悪い、ということが理由として挙げられる。 However, according to the knowledge of the present inventors, in the case of the prior art, the heat flow is close to the crystal edge part because the relative temperature of the liquid sealant is lower than the crystal, so that the heat flow is solid-liquid interface → crystal side face → liquid seal. A flow called a stop agent is generated, whereby the solid-liquid interface shape in the vicinity of the crystal edge becomes concave, and thus a polycrystal of crystals due to dislocation aggregation is generated. As a reason why the relative temperature of the liquid sealant is lower than the crystal, it is common to use boron trioxide as the material of the liquid sealant, but the thermal conductivity is low as a feature of boron trioxide. The reason is that heat transfer is also poor because of its high viscosity.

そこで、本発明の目的は、上記課題を解決し、ルツボ内の液体封止剤中に攪拌を目的とした邪魔板なる部材を配置することで、固液界面の凹面化による多結晶化を防ぎ、全域単結晶の生産歩留りを向上し得るＬＥＣ法による化合物半導体単結晶の製造方法を提供することにある。 Accordingly, an object of the present invention is to solve the above-mentioned problems and to prevent polycrystallization due to the concave surface of the solid-liquid interface by disposing a baffle plate for the purpose of stirring in the liquid sealant in the crucible. Another object of the present invention is to provide a method for producing a compound semiconductor single crystal by the LEC method capable of improving the production yield of the whole area single crystal.

なお、上記液体封止剤における熱伝達の悪さの問題は、ルツボ内の液体封止剤中に攪拌を目的とした邪魔板を配置して、液体封止剤を攪拌することが有効な解決策となると考えられ、特許文献１はこれに近似した邪魔板をもつものであるが、そもそも特許文献１は固液界面形状を凸面化させることとは別の観点から記述されており、また邪魔板を傾斜して配置することについては全く記載がない。本発明は、ルツボ内の液体封止剤中に攪拌に効果的な姿態で邪魔板を配置して、固液界面の凹面化による多結晶化を防ぎ、全域単結晶の生産歩留りを向上させることにある。 The problem of poor heat transfer in the liquid sealant is an effective solution to stir the liquid sealant by arranging a baffle plate for stirring in the liquid sealant in the crucible. Patent Document 1 has a baffle plate similar to this, but Patent Document 1 is originally described from a viewpoint different from making the solid-liquid interface shape convex. There is no description at all about the arrangement. The present invention arranges a baffle plate in a liquid sealing agent in a crucible in an effective form for stirring, prevents polycrystallization due to the concave surface of the solid-liquid interface, and improves the production yield of the whole area single crystal. It is in.

上記目的を達成するため、本発明は、次のように構成したものである。 In order to achieve the above object, the present invention is configured as follows.

請求項１の発明に係る化合物半導体単結晶の製造方法は、耐圧容器内の加熱されたルツボをルツボ軸で支え、ルツボに原料融液、液体封止剤を収納し、ルツボを回転させつつ、原料融液に種結晶を接触させてこれを引き上げることにより単結晶を育成する化合物半導体単結晶の製造方法（ＬＥＣ法）において、上記ルツボの内壁面と単結晶の外周との間における液体封止剤中に、液体封止剤の攪拌を目的として複数枚の邪魔板を縦形に配置し、その各邪魔板を、平面内で見て、ルツボの回転方向と逆方向にルツボ半径線から鋭角だけ傾け、この傾けた邪魔板の存在により上記ルツボの回転に伴って液体封止剤を攪拌しつつ、単結晶を引き上げることを特徴とする。 In the method for producing a compound semiconductor single crystal according to the invention of claim 1, the heated crucible in the pressure vessel is supported by the crucible shaft, the raw material melt and the liquid sealant are accommodated in the crucible, and the crucible is rotated. In a compound semiconductor single crystal manufacturing method (LEC method) for growing a single crystal by bringing a seed crystal into contact with a raw material melt and pulling it up, liquid sealing between the inner wall of the crucible and the outer periphery of the single crystal In the agent, a plurality of baffle plates are arranged vertically for the purpose of stirring the liquid sealant, and each baffle plate is viewed in a plane and only an acute angle from the crucible radius line in the direction opposite to the crucible rotation direction. The single crystal is pulled up while the liquid sealant is stirred with the rotation of the crucible by the presence of the inclined baffle plate.

請求項２の発明は、請求項１記載の化合物半導体単結晶の製造方法において、上記邪魔板をルツボ半径線から傾ける設置傾斜角θを３０°〜６０°の範囲に設定することを特徴とする。 According to a second aspect of the present invention, in the method for producing a compound semiconductor single crystal according to the first aspect, an installation inclination angle θ for inclining the baffle plate from the crucible radius line is set in a range of 30 ° to 60 °. .

請求項３の発明は、請求項１又は２記載の化合物半導体単結晶の製造方法において、上記邪魔板を２〜４枚周方向に等間隔で設けることを特徴とする。 According to a third aspect of the present invention, in the method for producing a compound semiconductor single crystal according to the first or second aspect, 2 to 4 baffle plates are provided at equal intervals in the circumferential direction.

＜発明の要点＞
本発明は、上記課題を解決するために、ＬＥＣ法による例えばＧａＡｓ単結晶の製造方法において、原料容器たるルツボ内の液体封止剤中に、液体封止剤の攪拌を目的とした邪魔板なる部材を、攪拌に適切な傾斜角（設置傾斜角θ）で配置して、結晶の多結晶化をなくすものである。攪拌に適切な設置傾斜角θは、各邪魔板をルツボの回転方向と逆方向に回転させて傾ける場合は鋭角、好ましくは３０°〜６０°の範囲であり、邪魔板は結晶を取り囲む周方向に２〜４枚等間隔で設けられる。 <Key points of the invention>
In order to solve the above-described problems, the present invention provides a baffle plate for the purpose of stirring a liquid sealing agent in a liquid sealing agent in a crucible serving as a raw material container in a method for producing, for example, a GaAs single crystal by the LEC method. The members are arranged at an inclination angle suitable for stirring (installation inclination angle θ) to eliminate crystal polycrystallization. The installation inclination angle θ suitable for stirring is an acute angle when each baffle plate is tilted by rotating it in the direction opposite to the rotation direction of the crucible, preferably 30 ° to 60 °, and the baffle plate surrounds the crystal. 2 to 4 are provided at equal intervals.

上記の手段をとった理由は下記の通りである。 The reason why the above measures are taken is as follows.

結晶エッジ部付近で発生する固液界面形状の凹面化を防止するためには、結晶側面から液体封止剤への放熱量を低減する必要がある。結晶側面から液体封止剤への放熱量を低減するには、結晶側面の温度に対して液体封止剤の温度を高く、若しくは液体封止剤と結晶との相対温度差を低減してやれば良い。 In order to prevent the solid-liquid interface shape from becoming concave near the crystal edge, it is necessary to reduce the amount of heat released from the crystal side surface to the liquid sealant. In order to reduce the amount of heat released from the crystal side surface to the liquid sealant, the temperature of the liquid sealant should be higher than the temperature of the crystal side surface, or the relative temperature difference between the liquid sealant and the crystal should be reduced. .

従来技術の問題点にも記載したが、液体封止剤は熱伝導率が低く、粘性が高い材料である。よって、抵抗加熱ヒータに近いルツボ側壁近傍で加熱された液体封止剤の熱が、ルツボ中央に近い結晶エッジ部付近に伝わりにくい状態となっている。 As described in the problems of the prior art, the liquid sealant is a material having low thermal conductivity and high viscosity. Therefore, the heat of the liquid sealant heated in the vicinity of the crucible side wall near the resistance heater is not easily transmitted to the vicinity of the crystal edge near the center of the crucible.

そこで、本発明では、液体封止剤に強制的に対流を起こさせ熱伝達率を向上させることによって結晶エッジ部付近の液体封止剤の温度を上昇させるべく、結晶とルツボの間の液体封止剤内にルツボの回転を利用した液体封止剤の攪拌を目的とした邪魔板を設置する手段をとった。その攪拌に適切な設置傾斜角θは、各邪魔板をルツボの回転方向と逆方向に回転させて傾ける場合は鋭角、好ましくは３０°〜６０°の範囲であり、邪魔板は結晶を取り囲む周方向に２〜４枚等間隔で設けられる。これにより、結晶エッジ部の液体封止剤の温度を効果的に上昇させることができ、固液界面→結晶側面→液体封止剤という熱流の抑制が図れ、結晶エッジ部付近の固液界面形状が凹面化防止、強いては転位集合による結晶の多結晶抑制が可能となる。 Therefore, in the present invention, the liquid seal between the crystal and the crucible is increased in order to raise the temperature of the liquid sealant near the crystal edge by forcibly causing convection in the liquid sealant and improving the heat transfer coefficient. A means for installing a baffle plate for the purpose of stirring the liquid sealant using the rotation of the crucible in the stopper was taken. The installation inclination angle θ suitable for the stirring is an acute angle when each baffle plate is tilted by rotating it in the direction opposite to the direction of rotation of the crucible, preferably 30 ° to 60 °. The baffle plate surrounds the crystal. Two to four sheets are provided at equal intervals in the direction. As a result, the temperature of the liquid sealant at the crystal edge can be effectively increased, the heat flow of the solid-liquid interface → crystal side face → liquid sealant can be suppressed, and the shape of the solid-liquid interface near the crystal edge However, it is possible to prevent the formation of a concave surface and to suppress polycrystals of crystals due to dislocation aggregation.

又、邪魔板を複数枚設置する様にしたのは、液体封止剤の温度の対称性を取りやすくする為にとった手段である。ちなみに液体封止剤の温度の対称性が悪いと、結晶にスリップが発生したり、部分的な転位増殖、多結晶の発生要因となる。 In addition, a plurality of baffle plates are installed in order to make it easy to achieve temperature symmetry of the liquid sealant. Incidentally, when the temperature symmetry of the liquid sealant is poor, slipping occurs in the crystal, causing partial dislocation growth and polycrystal generation.

本発明によれば、ＬＥＣ法による例えばＧａＡｓ単結晶の製造方法において、原料容器たるルツボ内の液体封止剤中に、液体封止剤の攪拌を目的として複数枚の邪魔板を、攪拌に適切な傾斜角（設置傾斜角θ）で配置し、その設置傾斜角θとして、各邪魔板をルツボの回転方向と逆方向に鋭角、好ましくは３０°〜６０°の範囲で傾けているので、攪拌を効果的に行うことができ、固液界面の凹面化による多結晶化を防ぎ、全域単結晶の生産歩留りを向上することができる。 According to the present invention, in a method for producing, for example, GaAs single crystal by the LEC method, a plurality of baffle plates are appropriately used for stirring in the liquid sealing agent in a crucible serving as a raw material container for the purpose of stirring the liquid sealing agent. Since the baffle plates are inclined at an acute angle, preferably in the range of 30 ° to 60 °, in the direction opposite to the rotation direction of the crucible, the stirring angle is set as the installation inclination angle θ. Thus, polycrystallization due to the concave surface of the solid-liquid interface can be prevented, and the production yield of the single crystal in the entire region can be improved.

以下、本発明を図示の実施の形態に基づいて説明する。 Hereinafter, the present invention will be described based on the illustrated embodiments.

本発明の製造方法を実施する成長装置の構成は、液体封止剤を攪拌する手段を除き、図４について上述したところと同一である。すなわち、この化合物半導体単結晶成長装置は、原料融液を収容するＰＢＮルツボ５と、このＰＢＮルツボ５を受ける為のルツボ軸４と、ルツボ５内の原料融液及び液体封止剤を加熱すべくルツボ５の周囲を取り巻いて設置された抵抗加熱ヒータ８としてのグラファイトヒータと、上記原料融液に接触させた種結晶７を支持し、上記原料融液９から成長する結晶を引き上げる引上軸３とを有する。 The structure of the growth apparatus for carrying out the production method of the present invention is the same as that described above with reference to FIG. 4 except for the means for stirring the liquid sealant. That is, this compound semiconductor single crystal growth apparatus heats the PBN crucible 5 containing the raw material melt, the crucible shaft 4 for receiving the PBN crucible 5, the raw material melt and the liquid sealant in the crucible 5. A graphite heater as a resistance heater 8 installed around the periphery of the crucible 5 and a pulling shaft for supporting the seed crystal 7 brought into contact with the raw material melt and pulling up the crystal grown from the raw material melt 9. 3.

上記ルツボ５の内壁面と化合物半導体単結晶１０の外周との間における液体封止剤６中には、液体封止剤の攪拌を目的として複数枚、ここでは３枚の長方形の邪魔板１１が縦形に配置されている。これらの邪魔板１１は、邪魔板から上方に延在する取付部材１２を介して、ヒータ８の外周囲に配置した断熱部材１３の頂部に取り付けられている。 In the liquid sealant 6 between the inner wall surface of the crucible 5 and the outer periphery of the compound semiconductor single crystal 10, a plurality of, here, three rectangular baffle plates 11 are provided for the purpose of stirring the liquid sealant. It is arranged vertically. These baffle plates 11 are attached to the top of a heat insulating member 13 disposed on the outer periphery of the heater 8 via an attachment member 12 extending upward from the baffle plate.

邪魔板１１は、長さＤ×高さＨの長方形の耐熱性板材から成る。その長さＤは、ルツボ５の内壁面と単結晶１０の外周との間の間隔Ｇにほぼ等しい。また、高さＨは、液体封止剤（三酸化硼素）６の層厚さより高く、従って図３に示すように、液体封止剤６内に深く配置した場合でも、液体封止剤６から上に露出した状態になる。 The baffle plate 11 is made of a rectangular heat-resistant plate material of length D × height H. The length D is substantially equal to the distance G between the inner wall surface of the crucible 5 and the outer periphery of the single crystal 10. Further, the height H is higher than the layer thickness of the liquid sealant (boron trioxide) 6. Therefore, even when the liquid sealant 6 is disposed deeply as shown in FIG. It will be exposed above.

上記３枚の邪魔板１１は、図２に示すように、平面内で見て、邪魔板の設置位置におけるルツボ半径線Ｌに対し、ルツボの回転方向Ｋと逆方向に鋭角θだけ回転させて傾けられている。換言すれば、このルツボ半径線Ｌからのずれ角を邪魔板１１の設置傾斜角θとした場合、その角度θはルツボ５の回転方向Ｋが、時計回りであるか、反時計回りであるかによって次のようになる。 As shown in FIG. 2, the three baffle plates 11 are rotated by an acute angle θ in the direction opposite to the crucible rotation direction K with respect to the crucible radius line L at the baffle plate installation position as viewed in a plane. Tilted. In other words, when the deviation angle from the crucible radius line L is set as the installation inclination angle θ of the baffle plate 11, the angle θ indicates whether the rotation direction K of the crucible 5 is clockwise or counterclockwise. It becomes as follows.

０°＜θ＜９０°（時計回り）
９０°＜θ＜１８０°（反時計回り）
かかる邪魔板の設置傾斜角θとする理由は、上記角度範囲を取ることによって、ルツボ側壁で加熱された液体封止剤６を、ルツボ５の回転を利用して、ルツボ中央、つまりは結晶エッジ部付近へ向かう流れを効率良く発生させることが可能となり、強いては結晶エッジ部の液体封止剤の温度上昇が可能となるからである。 0 ° <θ <90 ° (clockwise)
90 ° <θ <180 ° (counterclockwise)
The reason for the installation inclination angle θ of the baffle plate is that the liquid sealing agent 6 heated on the side wall of the crucible is taken into the center of the crucible using the rotation of the crucible 5, that is, the crystal edge. This is because the flow toward the vicinity of the portion can be efficiently generated, and the temperature of the liquid sealant at the crystal edge portion can be increased.

本発明の効果を確認するため、以下のように実施例及び比較例について試作を行った。ここでは、試作例として、φ６サイズ（直径６インチ）のＧａＡｓ単結晶をＬＥＣ法により成長した。試作の方法を図１を用いて説明する。 In order to confirm the effect of the present invention, trial manufacture was carried out for the examples and comparative examples as follows. Here, as a prototype, a GaAs single crystal of φ6 size (diameter 6 inches) was grown by the LEC method. A prototype method will be described with reference to FIG.

図１のＬＥＣ法によるＧａＡｓ単結晶製造装置１を用いて、先ず原料の容器となるＰＢＮルツボ５にＧａを１２０００ｇ、Ａｓを１３０００ｇ、及びＡｓの揮発を防止するための三酸化硼素６を２０００ｇ入れ、これをチャンバー２内にセットした。又、引上軸３の先端に結晶の元となる種結晶７を取り付けた。なお、この種結晶７はＧａＡｓ融液と接する面を（１００）面とした。 First, 12,000 g of Ga, 13000 g of As, and 2000 g of boron trioxide 6 for preventing volatilization of As are placed in a PBN crucible 5 serving as a raw material container using the GaAs single crystal manufacturing apparatus 1 by the LEC method shown in FIG. This was set in the chamber 2. Further, a seed crystal 7 as a crystal source was attached to the tip of the pulling shaft 3. The seed crystal 7 has a (100) plane in contact with the GaAs melt.

又、本発明の特徴である上記邪魔板１１を、ＰＢＮルツボ５内の液体封止剤６中に挿入するよう配置した。邪魔板１１の材質には、ルツボの材質と同様のＰＢＮを用いた。 Further, the baffle plate 11 which is a feature of the present invention is disposed so as to be inserted into the liquid sealant 6 in the PBN crucible 5. As the material of the baffle plate 11, the same PBN as the material of the crucible was used.

チャンバー２に原料をセットした後、チャンバー２内を真空にし、不活性ガスを充填し、その後チャンバー２内に設置してある抵抗加熱ヒータ８に通電してチャンバー２内の温度を昇温させ、ＧａとＡｓを合成しＧａＡｓを作製する。その後、更に昇温させＧａＡｓを融液化させ、ＧａＡｓ融液９とした。 After setting the raw material in the chamber 2, the chamber 2 is evacuated and filled with an inert gas, and then the resistance heater 8 installed in the chamber 2 is energized to raise the temperature in the chamber 2, Ga and As are synthesized to produce GaAs. Thereafter, the temperature was further raised to melt GaAs to obtain a GaAs melt 9.

続いて、引上軸３を１０ｒｐｍ、ルツボ軸４を回転方向を逆として２０ｒｐｍで回転させた。尚、当試作ではルツボの回転方法は時計回りに設定した。この状態で、引上軸３を先端に取り付けてある種結晶７がＧａＡｓ融液９に接触するまで下降させ、続いて、抵抗加熱ヒータ８の設定温度を徐々に下げつつ、引上軸３を１０mm／ｈの速度で上昇させることで、ＧａＡｓ単結晶１０の成長試作を行なった。 Subsequently, the pull-up shaft 3 was rotated at 10 rpm, and the crucible shaft 4 was rotated at 20 rpm with the rotation direction being reversed. In this prototype, the crucible rotation method was set clockwise. In this state, the pull-up shaft 3 is lowered until the seed crystal 7 attached to the tip comes into contact with the GaAs melt 9, and then the set temperature of the resistance heater 8 is gradually lowered while the pull-up shaft 3 is moved. The growth trial manufacture of the GaAs single crystal 10 was performed by raising at a speed of 10 mm / h.

又、本発明の効果を確認するため、邪魔板１１の設置傾斜角θを４５°に固定した状態で、邪魔板１１の設置枚数を０〜５枚と変更して試作を実施した。 In addition, in order to confirm the effect of the present invention, the prototype was implemented by changing the number of baffle plates 11 to be set to 0 to 5 with the installation inclination angle θ of the baffle plate 11 fixed at 45 °.

又、邪魔板１１の設置枚数を３枚に固定して、それら邪魔板１１の設置傾斜角θを０°から３０°おきに１８０°まで変えて試作を実施した。 Further, the number of the baffle plates 11 installed was fixed to 3, and the trial was carried out by changing the installation inclination angle θ of the baffle plates 11 from 0 ° to 180 ° every 30 °.

以上２通りの試作例について、各設定毎に１０ロットの結晶成長を実施し、結晶の単結晶化率を比較した。ここで、結晶の単結晶化率とは、結晶のウェハ取得可能な理想有効長に対して、結晶外観で多結晶でない単結晶部分の有効長の割合を示す指標である。 With respect to the above two prototypes, 10 lots of crystal growth were carried out for each setting, and the single crystallization ratios of the crystals were compared. Here, the single crystallization rate of a crystal is an index indicating the ratio of the effective length of a single crystal portion that is not polycrystalline in terms of crystal appearance to the ideal effective length that can be obtained for a crystal wafer.

試作の結果を下記表１、表２に示す。

表１の結果から判るように、邪魔板１１を用いた場合の方が結晶の単結晶化率が高い結果となった。又、邪魔板１１の設置枚数が２枚以上の場合に歩留りが大幅に向上しており、４枚設置以降は歩留りが頭打ちの状態となった。当結果から本発明の請求項３の効果が確認できた。 The results of the trial production are shown in Tables 1 and 2 below.

As can be seen from the results in Table 1, when the baffle plate 11 was used, the single crystal crystallization rate was higher. Further, the yield was greatly improved when the number of the baffle plates 11 installed was 2 or more, and the yield reached a peak after the installation of 4 sheets. From this result, the effect of claim 3 of the present invention was confirmed.

又、表２の結果から、ルツボ回転方向が時計回りの場合、邪魔板１１の設置傾斜角θが０°＜θ＜９０°の範囲にあるときに歩留りが向上しており、当特許の効果が確認出来た。当結果はルツボ回転方向が時計回り時の結果であるが、反時計回りの場合は、邪魔板設置角度が軸対称の関係にあるので同様の結果が得られるのは明白である。 Further, from the results of Table 2, when the crucible rotation direction is clockwise, the yield is improved when the installation inclination angle θ of the baffle plate 11 is in the range of 0 ° <θ <90 °. Was confirmed. This result is the result when the crucible rotation direction is clockwise, but when it is counterclockwise, it is clear that the same result can be obtained because the baffle plate installation angle is in an axisymmetric relationship.

上記試作結果から本発明の請求項２で規定した条件が最適であると判断できる。 From the result of the trial production, it can be determined that the conditions defined in claim 2 of the present invention are optimal.

このように本発明の効果として、結晶エッジ部付近での固液界面形状を効果的に凸化することができ、結晶に発生する転位の集合が低減され、単結晶の収率向上がはかれるようになった。 As described above, as an effect of the present invention, the solid-liquid interface shape in the vicinity of the crystal edge portion can be effectively convexed, the number of dislocations generated in the crystal is reduced, and the yield of the single crystal can be improved. Became.

上記実施例では、ＧａＡｓ単結晶をＬＥＣ法により製造する方法を例にして説明したが、ＧａＡｓ以外の他の化合物半導体単結晶をＬＥＣ法により製造する方法についても適用することが可能である。 In the above embodiment, the method of manufacturing a GaAs single crystal by the LEC method has been described as an example. However, the present invention can also be applied to a method of manufacturing a compound semiconductor single crystal other than GaAs by the LEC method.

本発明の化合物半導体単結晶の製造方法を実施するための化合物半導体単結晶製造装置の概略構成図である。It is a schematic block diagram of the compound semiconductor single crystal manufacturing apparatus for enforcing the manufacturing method of the compound semiconductor single crystal of this invention. 本発明の製造方法において邪魔板を液体封止剤内に設置した状態を示す概略平面図である。It is a schematic plan view which shows the state which installed the baffle plate in the liquid sealing agent in the manufacturing method of this invention. 本発明の実施形態に係る図２のＡ−Ａ′縦断面図である。FIG. 3 is a vertical cross-sectional view taken along the line AA ′ of FIG. 2 according to the embodiment of the present invention. 従来の化合物半導体単結晶の製造装置の概略構成図である。It is a schematic block diagram of the manufacturing apparatus of the conventional compound semiconductor single crystal.

符号の説明Explanation of symbols

１化合物半導体単結晶製造装置（ＧａＡｓ単結晶製造装置）
２チャンバー
３引上軸
４ルツボ軸
５ルツボ（ＰＢＮルツボ）
６液体封止剤（三酸化硼素）
７種結晶
８ヒータ（抵抗加熱ヒータ）
９原料融液（ＧａＡｓ融液）
１０化合物半導体単結晶（ＧａＡｓ単結晶）
１１邪魔板
１２取付部材
１３断熱部材
Ｄ長さ
Ｈ高さ
Ｇ間隔
Ｋルツボの回転方向
Ｌルツボ半径線
θ 設置傾斜角 1 Compound semiconductor single crystal manufacturing equipment (GaAs single crystal manufacturing equipment)
2 Chamber 3 Pulling shaft 4 Crucible shaft 5 Crucible (PBN crucible)
6 Liquid sealant (boron trioxide)
7 Seed crystal 8 Heater (resistance heater)
9 Raw material melt (GaAs melt)
10 Compound semiconductor single crystal (GaAs single crystal)
11 baffle plate 12 mounting member 13 heat insulating member D length H height G interval K crucible rotation direction L crucible radius line θ installation inclination angle

Claims

耐圧容器内の加熱されたルツボをルツボ軸で支え、ルツボに原料融液、液体封止剤を収納し、ルツボを回転させつつ、原料融液に種結晶を接触させて、これを引き上げることにより単結晶を育成する化合物半導体単結晶の製造方法において、
上記ルツボの内壁面と単結晶の外周との間における液体封止剤中に、液体封止剤の攪拌を目的として複数枚の邪魔板を縦形に配置し、
その各邪魔板を、平面内で見て、ルツボの回転方向と逆方向にルツボ半径線から鋭角だけ傾け、
この傾けた邪魔板の存在により上記ルツボの回転に伴って液体封止剤を攪拌しつつ、単結晶を引き上げることを特徴とする化合物半導体単結晶の製造方法。 By supporting the heated crucible in the pressure vessel with the crucible shaft, storing the raw material melt and liquid sealant in the crucible, rotating the crucible, bringing the seed crystal into contact with the raw material melt, and pulling it up In a method for producing a compound semiconductor single crystal for growing a single crystal,
In the liquid sealant between the inner wall surface of the crucible and the outer periphery of the single crystal, a plurality of baffle plates are arranged vertically for the purpose of stirring the liquid sealant,
Each of the baffle plates is viewed in a plane, and is inclined at an acute angle from the crucible radius line in the direction opposite to the crucible rotation direction,
A method for producing a compound semiconductor single crystal, wherein the single crystal is pulled up while stirring the liquid sealant as the crucible rotates due to the presence of the inclined baffle plate.

請求項１記載の化合物半導体単結晶の製造方法において、
上記邪魔板をルツボ半径線から傾ける設置傾斜角θを３０°〜６０°の範囲に設定することを特徴とする化合物半導体単結晶の製造方法。 In the manufacturing method of the compound semiconductor single crystal of Claim 1,
A method for producing a compound semiconductor single crystal, wherein an installation inclination angle θ for inclining the baffle plate from a crucible radial line is set in a range of 30 ° to 60 °.

請求項１又は２記載の化合物半導体単結晶の製造方法において、
上記邪魔板を２〜４枚周方向に等間隔で設けることを特徴とする化合物半導体単結晶の製造方法。 In the manufacturing method of the compound semiconductor single crystal of Claim 1 or 2,
2. A method for producing a compound semiconductor single crystal, comprising providing 2 to 4 baffle plates at equal intervals in a circumferential direction.