JP2001261485A - Device and method for producing single crystal - Google Patents
Device and method for producing single crystalInfo
- Publication number
- JP2001261485A JP2001261485A JP2000078603A JP2000078603A JP2001261485A JP 2001261485 A JP2001261485 A JP 2001261485A JP 2000078603 A JP2000078603 A JP 2000078603A JP 2000078603 A JP2000078603 A JP 2000078603A JP 2001261485 A JP2001261485 A JP 2001261485A
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- single crystal
- diameter
- rotation speed
- melt
- pulling
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- Crystals, And After-Treatments Of Crystals (AREA)
- Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は単結晶の製造装
置、特に引き上げ法（チョクラルスキー法）を適用した
Ｂｉ12ＧｅＯ20単結晶（以下、ＢＧＯと称す）の製造装
置及び単結晶の製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a single crystal, and more particularly to an apparatus and a method for producing a Bi 12 GeO 20 single crystal (hereinafter referred to as BGO) to which a pulling method (Czochralski method) is applied. It is about.
【０００２】[0002]
【従来の技術】従来からファラデー効果およびポッケル
ス効果を共に有する単結晶として、ＢＧＯが知られてい
る。一般に、ＢＧＯは引上げ法により製造されている。
図６は例えば特開平１−２３４３９９号公報に示された
単結晶育成炉の断面構造の模式図である。図６におい
て、１はＢＧＯ、２はＢＧＯ１の原料となる融液、３は
この融液２からＢＧＯ１を育成するための種結晶、４は
この種結晶３を先端に取り付けた引上げ軸、５は引上げ
軸４と同心円下に据付けた白金製るつぼ、６は白金製る
つぼ５を囲う耐火物、７は白金製アフターヒーター、８
は白金製アフターヒーター７を囲う耐火物、９は耐火物
６と耐火物８との間に設置されたスペーサ、１０は加熱
用の高周波コイル、１００は単結晶育成炉である。2. Description of the Related Art BGO is conventionally known as a single crystal having both the Faraday effect and the Pockels effect. Generally, BGO is manufactured by a pulling method.
FIG. 6 is a schematic view of a sectional structure of a single crystal growing furnace disclosed in, for example, Japanese Patent Application Laid-Open No. 1-234399. In FIG. 6, 1 is BGO, 2 is a melt used as a raw material of BGO1, 3 is a seed crystal for growing BGO1 from this melt 2, 4 is a pulling shaft having this seed crystal 3 attached to the tip, 5 is A platinum crucible installed concentrically with the pulling shaft 4, 6 is a refractory surrounding the platinum crucible 5, 7 is a platinum afterheater, 8
Is a refractory surrounding the platinum afterheater 7, 9 is a spacer installed between the refractory 6 and the refractory 8, 10 is a high-frequency coil for heating, and 100 is a single crystal growing furnace.
【０００３】次に動作について説明する。ＢＧＯ１の原
料となる純度９９．９７％の酸化ビスマス（Ｂｉ2Ｏ3）
と純度９９．９９％の二酸化ゲルマニウム（ＧｅＯ2）
とをＢｉ12ＧｅＯ20となる割合で混合し、白金製るつぼ
５に充填する。白金製るつぼ５は高周波コイル１０から
の高周波誘導加熱で１０００℃近くの高温に加熱される
ため、断熱性のある耐火物６で囲っている。Next, the operation will be described. Bismuth oxide (Bi 2 O 3 ) with a purity of 99.97%, which is a raw material for BGO1
And 99.99% pure germanium dioxide (GeO 2 )
Are mixed at a ratio of Bi 12 GeO 20 and filled in a crucible 5 made of platinum. Since the platinum crucible 5 is heated to a high temperature of about 1000 ° C. by high-frequency induction heating from the high-frequency coil 10, it is surrounded by a refractory 6 having heat insulation.
【０００４】白金製るつぼ５を介して高周波コイル１０
で加熱されたＢｉ12ＧｅＯ20は溶融し、融液２となる。
この融液２を９３０℃に維持しつつ、引上げ軸４の先端
に取り付けた種結晶３を前記融液２に浸し、種結晶３を
回転させながら引上げることによりＢＧＯ１が育成でき
る。A high-frequency coil 10 is connected via a platinum crucible 5.
The Bi 12 GeO 20 heated in the step is melted to form a melt 2.
While maintaining the melt 2 at 930 ° C., the seed crystal 3 attached to the tip of the pulling shaft 4 is immersed in the melt 2 and pulled up while rotating the seed crystal 3, whereby the BGO 1 can be grown.
【０００５】このような加熱方式の場合、通常炉内の温
度勾配が大きと、育成するＢＧＯ１の結晶品質は結晶育
成炉１００内の温度分布により大きく左右されるため
に、引上げたＢＧＯ１が冷却時に割れたり、結晶内に熱
歪みによる欠陥が発生してクラックの原因となる。[0005] In the case of such a heating method, since the temperature gradient in the normal furnace is large and the crystal quality of the grown BGO1 is greatly influenced by the temperature distribution in the crystal growing furnace 100, the pulled BGO1 is cooled during cooling. Cracks and defects due to thermal strain occur in the crystal, which cause cracks.
【０００６】これらを回避するため、白金製るつぼ５上
にスペーサ９を介して、白金製アフターヒーター７と断
熱性のある耐火物８を配置して結晶育成炉１００内の温
度勾配を小さくする方法が取られている。In order to avoid these problems, a method of reducing the temperature gradient in the crystal growing furnace 100 by disposing a platinum afterheater 7 and a refractory material 8 with heat insulation on a platinum crucible 5 via a spacer 9 via a spacer 9 is provided. Has been taken.
【０００７】本例では融液２の液面からＢＧＯ１の引上
げ方向上方１０ｍｍまでの温度勾配を５０〜７５℃／ｃ
ｍに調整し、それに引続く１５０ｍｍに至るまでの温度
勾配を１０℃／ｃｍ以下に調整している。また、ＢＧＯ
１の引上げ速度は１ｍｍ／ｈ、回転速度は温度勾配によ
り８〜１０ｒｐｍの範囲にある一定値としている。In this example, the temperature gradient from the liquid surface of the melt 2 to 10 mm above the BGO 1 in the pulling direction is 50 to 75 ° C./c.
m, and the subsequent temperature gradient up to 150 mm is adjusted to 10 ° C./cm or less. Also, BGO
The pulling speed of 1 is 1 mm / h, and the rotating speed is a constant value in the range of 8 to 10 rpm depending on the temperature gradient.
【０００８】[0008]
【発明が解決しようとする課題】（１）従来技術の問題
点の説明 ＢＧＯ１を育成するに当り、育成するＢＧＯ１の直径と
白金製るつぼ５の直径、及びＢＧＯ１の引上げ速度や回
転速度等の育成条件の設定によっては下記のような問題
点が発生した。 １．回転速度が速すぎＢＧＯ１と融液２の境界面（以
下、固液界面）の状態が凹面の場合に、ＢＧＯ１内に数
〜数十μｍの気泡が混入し易い。 ２．更に凹面化が進むと単結晶の育成過程でＢＧＯ１と
融液２とが分断されることがある。 ３．逆に回転速度が遅すぎ固液界面が凸面の場合にＢＧ
Ｏ１内に変色した部分（以下、コアーと称す）が発生す
る。 ４．ＢＧＯ１の直径が大きくなると内部の熱放散が悪く
なり、歪み等の内部欠陥が発生する。 ５．１のような現象を解消するために種結晶の引き上げ
速度を一義的に遅くすると種結晶から目標直径に成長す
るまでに長時間要する。(1) Description of the problems of the prior art In growing BGO1, the diameter of the BGO1 to be grown, the diameter of the platinum crucible 5, and the growth speed and rotation speed of the BGO1 are raised. Depending on the setting of the conditions, the following problems occurred. 1. When the rotation speed is too high, when the state of the boundary surface between the BGO 1 and the melt 2 (hereinafter, the solid-liquid interface) is a concave surface, bubbles of several to several tens μm are easily mixed in the BGO 1. 2. When the concave surface is further advanced, the BGO 1 and the melt 2 may be separated during the process of growing the single crystal. 3. Conversely, if the rotation speed is too slow and the solid-liquid interface is convex,
A discolored portion (hereinafter referred to as a core) occurs in O1. 4. As the diameter of the BGO 1 increases, the internal heat dissipation deteriorates and internal defects such as distortion occur. If the pulling speed of the seed crystal is uniquely reduced to eliminate the phenomenon as described in 5.1, it takes a long time to grow from the seed crystal to the target diameter.
【０００９】（２）発明の目的の説明 この発明は、上記のような問題点を解消するためになさ
れたもので、ＢＧＯを安定に且つ、効率的に育成するこ
とができる単結晶の製造装置及び単結晶の製造方法を得
ることを目的する。(2) Description of the Object of the Invention The present invention has been made in order to solve the above problems, and has an apparatus for producing a single crystal capable of stably and efficiently growing BGO. And a method for producing a single crystal.
【００１０】[0010]
【課題を解決するための手段】この発明に係る単結晶の
製造装置は、充填した単結晶原料を加熱して融液を作る
単結晶育成炉と、前記単結晶育成炉に加熱用電力を供給
する加熱電源と、前記単結晶育成炉中の融液の液面に垂
直に接触させた軸をその中心軸周りに回転させながら軸
端面に被着した融液を単結晶として前記軸と共に引き上
げる引上げ機構と、この引き上げた単結晶の直径を算出
する直径算出手段と、前記算出された単結晶の直径に応
じて前記単結晶が目標直径に成長するまで単結晶の引上
げ速度と前記軸の回転速度、及び前記加熱電源の出力を
変化させる第１の制御手段と、前記単結晶が目標直径に
成長後、前記単結晶が目標長に達するまでは、前記引上
げ速度と前記回転速度を一定とし、前記供給する加熱用
電力のみを前記単結晶の直径の変化に応じて変化させる
第２の制御手段とを備えたものである。この発明に係る
単結晶の製造装置における第１の制御手段は、前記単結
晶の直径が所定値以下の場合は前記引き上げ速度と回転
速度を一定値に設定すると共に、前記加熱電源の出力を
一定値で下げ、また、前記単結晶の直径が前記所定値以
上で、且つ、前記目標直径以下の場合は前記引き上げ速
度と回転速度を前記単結晶の直径に逆比例して下げると
共に、前記加熱電源の出力を結晶直径の増加に伴って増
加するように制御するものである。この発明に係る単結
晶の製造装置における第２の制御手段は、前記引き上げ
速度と回転速度を、前記単結晶の直径が前記所定値以下
の場合よりも低い引き上げ速度と回転速度で一定値に設
定すると共に、前記加熱電源の出力を前記単結晶の直径
の変化に応じて制御するものである。According to the present invention, there is provided an apparatus for producing a single crystal, comprising: a single crystal growing furnace for heating a charged single crystal raw material to form a melt; and a heating power supply to the single crystal growing furnace. A heating power source, and pulling up the melt adhered to the shaft end face as a single crystal together with the shaft while rotating the shaft perpendicular to the liquid surface of the melt in the single crystal growing furnace around its central axis. A mechanism, diameter calculating means for calculating the diameter of the pulled single crystal, and a pulling speed of the single crystal and a rotation speed of the shaft until the single crystal grows to a target diameter according to the calculated diameter of the single crystal. And a first control means for changing the output of the heating power supply, after the single crystal has grown to a target diameter, until the single crystal reaches a target length, the pulling speed and the rotation speed are constant, Only the heating power to be supplied is It is obtained by a second control means for changing in response to changes in the diameter of the crystal. When the diameter of the single crystal is equal to or less than a predetermined value, the first control means in the apparatus for manufacturing a single crystal according to the present invention sets the pulling speed and the rotation speed to constant values, and keeps the output of the heating power supply constant. When the diameter of the single crystal is equal to or larger than the predetermined value and equal to or smaller than the target diameter, the pulling speed and the rotation speed are reduced in inverse proportion to the diameter of the single crystal, and the heating power Is controlled so as to increase as the crystal diameter increases. The second control means in the apparatus for producing a single crystal according to the present invention sets the pulling speed and the rotation speed to constant values at a lower pulling speed and a lower rotation speed than when the diameter of the single crystal is equal to or less than the predetermined value. In addition, the output of the heating power supply is controlled according to a change in the diameter of the single crystal.
【００１１】この発明に係る単結晶の製造方法は、加熱
された単結晶育成炉中の融液を軸の端部に被着させ、そ
の軸をその中心周りに所定の回転速度で回転させながら
引上げ機構により前記融液を単結晶として引き上げる
時、前記単結晶の単位時間当たりの重量増加分から前記
単結晶の直径を算出する第１の工程と、前記単結晶が所
定の直径に成長後、目標直径に成長するまで前記単結晶
の引上げ速度と回転速度、及び前記単結晶育成炉の加熱
量を前記単結晶の直径に応じて変化させる第２の工程
と、前記単結晶が目標直径に成長後、前記単結晶が目標
長に達するまでは、前記引上げ速度と回転速度を一定と
して融液を前記引上げ機構で引き上げ、前記単結晶育成
炉の加熱量のみを前記単結晶の直径の変化に応じて変化
させる第３の工程とを備えものである。この発明に係る
単結晶の製造方法における第２の工程では、前記単結晶
の直径が所定値以下の場合は前記引き上げ速度と回転速
度を一定値に設定すると共に、前記加熱電源の出力を一
定値で下げ、また、前記単結晶の直径が前記所定値以上
で、且つ、前記目標直径以下の場合は前記引き上げ速度
と回転速度を前記単結晶の直径に逆比例して下げると共
に、前記加熱電源の出力を結晶直径の増加にとなって増
加するように制御するものである。この発明に係る単結
晶の製造方法における前記第３の工程では、前記引き上
げ速度と回転速度を、前記第２の工程において単結晶の
直径が所定値以下の場合よりも低い引き上げ速度と回転
速度で一定値に設定すると共に、前記加熱電源の出力を
前記単結晶の直径の変化に応じて制御するものである。In the method for producing a single crystal according to the present invention, a melt in a heated single crystal growing furnace is applied to an end of a shaft, and the shaft is rotated around a center thereof at a predetermined rotation speed. A first step of calculating the diameter of the single crystal from a weight increase per unit time of the single crystal when the melt is pulled up as a single crystal by a pulling mechanism; and A second step of changing the pulling speed and rotation speed of the single crystal until the diameter of the single crystal grows, and the heating amount of the single crystal growing furnace according to the diameter of the single crystal, and after the single crystal has grown to a target diameter. Until the single crystal reaches the target length, the melt is pulled up by the pulling mechanism while keeping the pulling speed and the rotation speed constant, and only the heating amount of the single crystal growing furnace is changed according to the change in the diameter of the single crystal. And the third step of changing Is Emono. In the second step of the method for producing a single crystal according to the present invention, when the diameter of the single crystal is equal to or less than a predetermined value, the pulling speed and the rotation speed are set to constant values, and the output of the heating power supply is set to a constant value. When the diameter of the single crystal is equal to or larger than the predetermined value and equal to or smaller than the target diameter, the pulling speed and the rotation speed are reduced in inverse proportion to the diameter of the single crystal, and the heating power supply is reduced. The output is controlled so as to increase as the crystal diameter increases. In the third step of the method for producing a single crystal according to the present invention, the pulling speed and the rotation speed are set at a lower pulling speed and a lower rotation speed than when the diameter of the single crystal is equal to or less than a predetermined value in the second step. In addition to setting the constant value, the output of the heating power supply is controlled according to the change in the diameter of the single crystal.
【００１２】[0012]
【発明の実施の形態】実施の形態１． （１）構成の詳細な説明 本実施の形態の詳細な動作説明を行う前に、本発明の概
要について説明する。ＢＧＯ１と融液２の境界面（以
下、固液界面）の状態が凹面の場合にＢＧＯ１内に気泡
が混入し易く、さらに凹面化が進むとＢＧＯ１と融液２
が分断してしまい、逆に固液界面が凸面の場合はコアー
が発生することが、これまでのＢＧＯ１の製造結果から
分かってきた。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 (1) Detailed Description of Configuration Before giving a detailed description of the operation of the present embodiment, an overview of the present invention will be described. When the state of the boundary surface between BGO 1 and melt 2 (hereinafter, the solid-liquid interface) is concave, air bubbles easily enter BGO 1, and when the surface is further concaved, BGO 1 and melt 2
Is broken, and conversely, when the solid-liquid interface is a convex surface, a core is generated from the results of the production of BGO1.
【００１３】そこで、固液界面の状態は融液２の対流と
密接な関係にあり、白金製るつぼ５を加熱することで発
生する白金製るつぼ５内での融液２の自然対流とＢＧＯ
１の回転速度による融液２の強制対流とが打消し合うよ
うに制御すれば、固液界面の状態を平面に出来ることが
分かった。また、ＢＧＯ１の直径が大きくなると内部の
熱放散が悪くなり、熱歪みを生じる。この現象を回避す
る為、引上げ速度を遅くすれば良いことが分かった。さ
らに、加熱用の高周波コイル１０への供給電力を適正値
に減少させることでＢＧＯ１の成長を加速できることが
分かった。本発明の単結晶育成装置は引上げ法を適用し
てＢＧＯ１を育成するに当り、上記の結果を踏まえ、育
成時のＢＧＯ１の直径に応じてＢＧＯ１の引上げ速度と
回転速度及び加熱用の高周波コイル１０への供給電力を
コンピュータ制御で自動的に変化させることにより、固
液界面の状態を平面に維持できるようにした。Therefore, the state of the solid-liquid interface is closely related to the convection of the melt 2 and the natural convection of the melt 2 in the platinum crucible 5 generated by heating the platinum crucible 5 and the BGO.
It was found that the state of the solid-liquid interface can be made flat by controlling so that the forced convection of the melt 2 at the rotation speed of 1 cancels out. In addition, when the diameter of the BGO 1 increases, the internal heat dissipation deteriorates, and thermal distortion occurs. To avoid this phenomenon, it was found that the pulling speed should be reduced. Furthermore, it was found that the growth of BGO1 can be accelerated by reducing the power supplied to the heating high-frequency coil 10 to an appropriate value. In growing the BGO1 by applying the pulling method, the single crystal growing apparatus of the present invention takes into account the above results, and based on the diameter of the BGO1 at the time of growing, the pulling speed and rotation speed of the BGO1 and the high-frequency coil 10 for heating. The state of the solid-liquid interface can be maintained flat by automatically changing the supply power to the computer under computer control.
【００１４】以下この発明の実施の形態１を添付図面に
従って説明する。図１は本実施の形態に係る単結晶製造
装置の構成を示すブロック図である。図１において、１
００は結晶育成炉であり、その内部の構成は図６に示し
た従来の結晶育成炉と同様であるのでその説明は省略す
る。２０は結晶育成炉１００内の高周波コイル１０に電
力を供給する高周波加熱電源、２１は高周波加熱電源２
０の電力を制御するための電源制御機構、４は図示しな
い回転機構によりＢＧＯ１を回転させながら引上げる引
上げ軸、２２は引上げ軸４によって引き上げられるＢＧ
Ｏ１の重さを測定する重量測定機構、２３は引上げ軸４
の回転速度制御機構、２４は引上げ軸４の引上げ速度制
御機構、２５は電源制御機構２１、重量測定機構２２、
回転速度制御機構２３、及び引上げ速度制御機構２４を
集中管理するコンピュータ、２６は前記各機構２１〜２
４とコンピュータ２５を接続する通信ケーブルである。Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a single crystal manufacturing apparatus according to the present embodiment. In FIG. 1, 1
Reference numeral 00 denotes a crystal growing furnace, the internal configuration of which is the same as that of the conventional crystal growing furnace shown in FIG. Reference numeral 20 denotes a high-frequency heating power supply for supplying power to the high-frequency coil 10 in the crystal growth furnace 100, and reference numeral 21 denotes a high-frequency heating power supply 2.
A power control mechanism for controlling the power of 0, a pull-up shaft 4 for pulling up while rotating the BGO 1 by a rotating mechanism (not shown), and a BG 22 pulled up by the pull-up shaft 4
A weight measuring mechanism for measuring the weight of O1;
, A pulling speed control mechanism for the pulling shaft 4, a power control mechanism 21, a weight measuring mechanism 22,
A computer 26 for centrally managing the rotation speed control mechanism 23 and the pulling speed control mechanism 24,
4 is a communication cable for connecting the computer 4 to the computer 25.
【００１５】（２）動作の詳細な説明 （２−１）白金製るつぼ５内の融液２の対流についての
説明 ＢＧＯ１の原料を白金製るつぼ５に充填し、９５０℃ま
で加熱するとＢＧＯ１の原料は溶融して融液２となる。
この融液２は白金製るつぼ５の壁面が加熱されているの
で、図２（ａ）に示すように、融液２は白金製るつぼ５
の壁面から中央部に流れる自然対流となっている。この
融液２に引上げ軸４に取付けた種結晶３を浸し、引上げ
軸４を高速に回転させると、図２（ｂ）に示すように、
白金製るつぼ５内においては融液２の自然対流よりも種
結晶３の回転で生じる融液２の強制対流が勝り、融液２
は白金製るつぼ５の中央部から壁面に流れる状態とな
る。(2) Detailed Description of Operation (2-1) Explanation of Convection of Melt 2 in Platinum Crucible 5 The raw material of BGO1 is charged into a platinum crucible 5 and heated to 950 ° C. Melts into a melt 2.
Since the wall of the platinum crucible 5 of this melt 2 is heated, as shown in FIG.
The natural convection flows from the wall to the center. When the seed crystal 3 attached to the pulling shaft 4 is immersed in the melt 2 and the pulling shaft 4 is rotated at a high speed, as shown in FIG.
In the platinum crucible 5, the forced convection of the melt 2 generated by the rotation of the seed crystal 3 exceeds the natural convection of the melt 2 and the melt 2
Flows from the central portion of the platinum crucible 5 to the wall surface.
【００１６】（２−２）固液界面の形状と融液の対流の
相関についての説明 次に、ＢＧＯ１を育成時の固液界面の形状と融液２の対
流３０の相関について図３で説明する。図３（ａ）は自
然対流が強制対流よりも勝っている場合で、低温の融液
２は白金製るつぼ５の中央より底部に流れ込み、そして
底部より壁面に沿って上昇してからＢＧＯ１の中心部を
かすめ再び白金製るつぼ５の中央に流れ込むため、白金
製るつぼ５と同心円にあるＢＧＯ１の中心部は外周部よ
り白金製るつぼ５の中央に向けて固化が進むため、固液
界面は凸面になる。図３（ｂ）は自然対流と強制対流が
平衡状態の場合で、融液２の表面温度が一定になるので
ＢＧＯ１の中心部と外周部の固化が同時に進むため、固
液界面は平面になる。図３（ｃ）は自然対流よりも強制
対流が勝る場合で、高温の融液２が白金製るつぼ５の壁
面から中央へ沸き上がるため、ＢＧＯ１の中心部は外周
部より固化が遅れ、固液界面は凹面になる。(2-2) Explanation of Correlation between Shape of Solid-Liquid Interface and Convection of Melt Next, the correlation between the shape of the solid-liquid interface and convection 30 of melt 2 when growing BGO 1 will be described with reference to FIG. I do. FIG. 3 (a) shows a case where natural convection is stronger than forced convection, in which the low-temperature melt 2 flows from the center of the platinum crucible 5 to the bottom and rises along the wall surface from the bottom before the center of the BGO 1. The center of the BGO 1 which is concentric with the platinum crucible 5 is solidified from the outer peripheral portion toward the center of the platinum crucible 5 because the portion flows into the center of the platinum crucible 5 again. Become. FIG. 3B shows a case in which natural convection and forced convection are in an equilibrium state, and since the surface temperature of the melt 2 is constant, the solidification of the center and the outer periphery of the BGO 1 proceeds simultaneously, so that the solid-liquid interface becomes flat. . FIG. 3 (c) shows a case where forced convection is superior to natural convection. Since the high-temperature melt 2 boils from the wall surface of the platinum crucible 5 to the center, the solidification of the center of the BGO 1 is delayed from that of the outer periphery, and the solid-liquid interface Becomes concave.
【００１７】（２−３）ＢＧＯの製造についての説明 直径１００ｍｍ、深さ１００ｍｍの白金製るつぼ５を用
いて、直径４５ｍｍ、重量１５００ｇのＢＧＯ１を製造
する場合の動作について、図４の制御フローチャートに
従って説明する。結晶育成炉１００内の白金製るつぼ５
にＢＧＯ１の原料を充填し、高周波加熱電源２０の出力
を徐々に増加させながら高周波コイル１０に供給するよ
うに、コンピュータ２５から電源制御機構２１に指令を
出す。白金製るつぼ５を９５０℃まで加熱するとＢＧＯ
１の原料は完全に溶融され、融液２が得られる（ステッ
プＳ１）。次に、融液２の液面温度が種付け温度に適し
た９３０℃になるようにコンピュータ２５から電源制御
機構２１に指令を出して高周波加熱電源２０の出力を制
御する（ステップＳ２）。次に、この融液２に直径３ｍ
ｍの種結晶３を浸す（ステップＳ３）。この時、融液２
は前記の図２（ａ）の自然対流である。(2-3) Description of Production of BGO The operation of producing BGO 1 having a diameter of 45 mm and a weight of 1500 g using a platinum crucible 5 having a diameter of 100 mm and a depth of 100 mm will be described with reference to the control flowchart of FIG. explain. Platinum crucible 5 in crystal growing furnace 100
Is supplied from the computer 25 to the power supply control mechanism 21 so as to supply the high frequency coil 10 with the raw material of the BGO 1 and gradually increase the output of the high frequency heating power supply 20. When the platinum crucible 5 is heated to 950 ° C, BGO
The raw material 1 is completely melted to obtain a melt 2 (step S1). Next, a command is issued from the computer 25 to the power supply control mechanism 21 to control the output of the high-frequency heating power supply 20 so that the liquid surface temperature of the melt 2 becomes 930 ° C. suitable for the seeding temperature (step S2). Next, a diameter of 3 m
The m seed crystals 3 are immersed (step S3). At this time, melt 2
Is the natural convection shown in FIG.
【００１８】次に、ＢＧＯ１の重量を重量測定機構２２
からコンピュータ２５に読込み、単位時間当りの重量増
加分からＢＧＯ１の直径ｄを算出する（ステップＳ
４）。ＢＧＯ１の直径ｄが１０ｍｍ以下の場合と１０ｍ
ｍを越え４５ｍｍ未満の場合、及び目標直径の４５ｍｍ
に到達後ではそれぞれ異なる制御に分岐する（ステップ
Ｓ５、Ｓ６）。Next, the weight of the BGO 1 is measured by the weight measuring mechanism 22.
To the computer 25, and calculates the diameter d of the BGO 1 from the weight increase per unit time (step S
4). When the diameter d of BGO1 is 10 mm or less and 10 m
m and less than 45 mm, and 45 mm of the target diameter
After that, control branches to different controls (steps S5 and S6).
【００１９】ＢＧＯ１の直径ｄが目標直径に達さず、１
０ｍｍ以下の場合は、引上げ軸４の回転速度が２０ｒｐ
ｍになるようにコンピュータ２５から回転速度制御機構
２３に指令を出す（ステップＳ７）。回転速度が２０ｒ
ｐｍでは自然対流が強制対流に勝っており、固液界面は
凸面である（図３（ａ）参照）。本単結晶製造装置は種
結晶３の直径が１０ｍｍで自然対流と強制対流が平衡状
態になるが、ＢＧＯ１を安定に育成させるために固液界
面は凸面を維持している。同時に引上げ速度が２ｍｍ／
ｈになるようにコンピュータ２５から引上げ速度制御機
構２４に指令を出す（ステップＳ７）。融液２が固化す
る際に放出する潜熱により融液２や結晶育成炉１００内
雰囲気の温度が上昇しないよう高周波加熱電源２０から
高周波コイル１０に与える出力を一定値で下げて行くこ
とで（ステップＳ８）、種結晶３の直径は徐々に大きく
なってくる。When the diameter d of BGO1 does not reach the target diameter, 1
0 mm or less, the rotation speed of the pulling shaft 4 is 20 rpm
A command is issued from the computer 25 to the rotation speed control mechanism 23 so that the rotation speed becomes m (step S7). Rotation speed is 20r
At pm, natural convection exceeds forced convection, and the solid-liquid interface is convex (see FIG. 3A). In the present single crystal production apparatus, natural convection and forced convection are in an equilibrium state when the diameter of the seed crystal 3 is 10 mm, but the solid-liquid interface maintains a convex surface in order to stably grow BGO1. At the same time, the pulling speed is 2mm /
A command is issued from the computer 25 to the pull-up speed control mechanism 24 so as to reach h (step S7). The output from the high-frequency heating power supply 20 to the high-frequency coil 10 is reduced at a constant value so that the temperature of the melt 2 and the atmosphere in the crystal growth furnace 100 does not increase due to the latent heat released when the melt 2 solidifies (step S8) The diameter of the seed crystal 3 gradually increases.
【００２０】また、ＢＧＯ１の直径ｄが１０ｍｍを越
え、目標直径の４５ｍｍ未満の場合はＢＧＯ１の直径ｄ
に逆比例して回転速度を２０ｒｐｍから１０ｒｐｍに下
げる（ステップＳ６，９）。これは、ＢＧＯ１の直径ｄ
が約１０ｍｍで固液界面が平面（図３（ｂ）参照）にな
るが、直径ｄの増加に伴い自然対流より強制対流が勝
り、固液界面が凹面（図３（ｃ）参照）になるのを避け
るためである。また、ＢＧＯ１の直径ｄが大きくなるに
つれて内部の熱放散が悪くなるが、従来の技術で説明し
た通り、引上げ軸方向の温度勾配が大きいためＢＧＯ１
の中心部と外周部との温度差がさらに大きくなり熱歪み
を生じる。この熱歪みを回避するため、温度差が緩和す
る時間を設ける意味でＢＧＯ１の直径ｄに逆比例して引
上げ速度を２ｍｍ／ｈから１ｍｍ／ｈに下げる（ステッ
プＳ９）。回転速度と引上げ速度の制御と同期して、高
周波加熱電源２０の出力をＢＧＯ１の直径ｄの二次関数
でＰＩＤ制御することで（ステップＳ１０）、固液界面
の面積増加に比例して増加する潜熱の影響をなくし、Ｂ
ＧＯ１の成長を加速できる。If the diameter d of the BGO1 exceeds 10 mm and is less than the target diameter of 45 mm, the diameter d of the BGO1
The rotation speed is reduced from 20 rpm to 10 rpm in inverse proportion to (steps S6 and S9). This is the diameter d of BGO1
Is about 10 mm, the solid-liquid interface becomes flat (see FIG. 3 (b)), but as the diameter d increases, forced convection exceeds natural convection and the solid-liquid interface becomes concave (see FIG. 3 (c)). This is to avoid Further, as the diameter d of the BGO 1 increases, the internal heat dissipation deteriorates. However, as described in the related art, the temperature gradient in the direction of the pulling axis is large, so that the BGO 1 has a large temperature gradient.
The temperature difference between the central part and the outer peripheral part becomes larger, and thermal distortion occurs. In order to avoid this thermal distortion, the pulling speed is reduced from 2 mm / h to 1 mm / h in inverse proportion to the diameter d of the BGO 1 in order to provide time for the temperature difference to relax (step S9). By performing PID control of the output of the high-frequency heating power supply 20 with a quadratic function of the diameter d of the BGO 1 in synchronization with the control of the rotation speed and the pulling speed (step S10), the output increases in proportion to the increase in the area of the solid-liquid interface. Eliminate the effect of latent heat, B
The growth of GO1 can be accelerated.
【００２１】目標直径の４５ｍｍに到達後の場合は引上
げ速度は１ｍｍ／ｈで、回転速度は１０ｒｐｍで一定制
御とするが（ステップＳ１１）、高周波加熱電源２０の
出力は目標直径と重量からの算出直径値との差分による
ＰＩＤ制御を行うことで、直径４５±１ｍｍを維持でき
る（ステップＳ１２）。目標重量の１５００ｇに到達す
るまで、６０秒周期で前記の直径に応じた制御処理（ス
テップＳＳ４〜Ｓ１２）を繰り返す（ステップＳ１
３）。目標重量の１５００ｇに到達した後は（ステップ
Ｓ１３）、１時間で引上げ速度を１ｍｍ／ｈから３ｍｍ
／ｈに、回転速度を１０ｒｐｍから１３ｒｐｍに増加さ
せ、高周波加熱電源２０の出力を一定値で増加させるこ
とで、ＢＧＯ１と融液２を切り離す（ステップＳ１
４）。ここで、引上げ速度と回転速度を１時間かけて変
化させる目的は結晶のねじれ防止と、ＢＧＯ１の脱落防
止のためである。ＢＧＯ１の単位時間当りの重量増加分
が零になることで、ＢＧＯ１と融液２を切り離されたこ
とが分かる。ＢＧＯ１と融液２とが切り離されたことを
確認後、高周波加熱電源２０の出力を一定値で減少させ
（ステップＳ１５）、約１２０時間で室温まで戻す。室
温になったＢＧＯ１を結晶育成炉１００から取出して、
ＢＧＯ１の製造が完了する。実施の形態１の単結晶の製
造装置を用い、目標直径における種結晶の回転速度を７
ｒｐｍから１４ｒｐｍまでの８つの回転速度条件で単結
晶を育成した結果を図５の表に示す。表に示す通り、目
標直径での回転速度が１０±１ｒｐｍでは固液界面形状
が平面であり、育成結果として、回転速度９ｒｐｍでは
コアーが少なく、気泡がない。回転速度１０ｒｐｍでは
コアーがなく、気泡が少ない。回転速度１１ｒｐｍでは
コアーがなく、気泡が少ない。依って、目標直径での回
転速度が１０±１ｒｐｍでの育成結果は適正である。After reaching the target diameter of 45 mm, the pulling speed is 1 mm / h, the rotation speed is 10 rpm, and constant control is performed (step S11). However, the output of the high-frequency heating power supply 20 is calculated from the target diameter and weight. By performing the PID control based on the difference from the diameter value, the diameter can be maintained at 45 ± 1 mm (step S12). Until the target weight of 1500 g is reached, the control process (steps SS4 to S12) corresponding to the diameter is repeated in a cycle of 60 seconds (step S1).
3). After reaching the target weight of 1500 g (step S13), the pulling speed is increased from 1 mm / h to 3 mm in one hour.
/ H, the rotation speed is increased from 10 rpm to 13 rpm, and the output of the high frequency heating power supply 20 is increased at a constant value, thereby separating the BGO 1 and the melt 2 (step S1).
4). Here, the purpose of changing the pulling speed and the rotation speed over one hour is to prevent the crystal from twisting and to prevent the BGO 1 from falling off. When the weight increase per unit time of BGO1 becomes zero, it can be understood that BGO1 and melt 2 are separated. After confirming that the BGO 1 and the melt 2 have been separated, the output of the high-frequency heating power supply 20 is reduced at a constant value (step S15), and the temperature is returned to room temperature in about 120 hours. The room temperature BGO1 is taken out of the crystal growing furnace 100,
The manufacture of BGO1 is completed. The rotation speed of the seed crystal at the target diameter is set to 7 using the single crystal manufacturing apparatus of the first embodiment.
The results of growing a single crystal under eight rotation speed conditions from rpm to 14 rpm are shown in the table of FIG. As shown in the table, when the rotation speed at the target diameter is 10 ± 1 rpm, the shape of the solid-liquid interface is flat, and as a result of the growth, at a rotation speed of 9 rpm, there are few cores and no bubbles. At a rotation speed of 10 rpm, there is no core and there are few bubbles. At a rotation speed of 11 rpm, there is no core and there are few bubbles. Therefore, the growth result when the rotation speed at the target diameter is 10 ± 1 rpm is appropriate.
【００２２】しかし、回転速度が８ｒｐｍ以下ではコア
ーが大きく、また、回転速度が１２ｒｐｍ以上では気泡
の混入が多くなり、ＢＧＯ１と融液２とが分断されるこ
とがあり育成結果は適正ではない。However, when the rotation speed is 8 rpm or less, the core is large, and when the rotation speed is 12 rpm or more, the inclusion of bubbles increases, and the BGO 1 and the melt 2 may be separated from each other.
【００２３】[0023]
【発明の効果】以上のように、この発明によればＢＧＯ
の育成過程におけるＢＧＯと融液の分断はもちろん、気
泡の混入、コアー、熱歪み等の欠陥を回避してＢＧＯの
高品質化やＢＧＯ製造における歩留まりの向上と製造時
間の短縮が図れるので、生産性が大幅に改善できるとい
う効果がある。As described above, according to the present invention, BGO
In addition to the separation of BGO and the melt during the growth process of BGO, it is possible to improve the quality of BGO, improve the yield in BGO production and shorten the production time by avoiding defects such as mixing of bubbles, cores, and thermal distortion. The effect is that the performance can be greatly improved.
【図１】 この発明の実施の形態１による単結晶育成装
置の構成ブロック図である。FIG. 1 is a configuration block diagram of a single crystal growing apparatus according to a first embodiment of the present invention.
【図２】 白金製るつぼ内の融液の対流の説明図であ
る。FIG. 2 is an explanatory diagram of convection of a melt in a platinum crucible.
【図３】 白金製るつぼ内の融液の対流と固液界面との
相関の説明図である。FIG. 3 is an explanatory diagram of a correlation between a convection of a melt in a platinum crucible and a solid-liquid interface.
【図４】 この発明の実施の形態１における制御フロー
チャートである。FIG. 4 is a control flowchart according to the first embodiment of the present invention.
【図５】 本実施の形態における結晶の育成条件と育成
結果を表した表である。FIG. 5 is a table showing growth conditions and growth results of crystals in the present embodiment.
【図６】 従来の単結晶育成炉の断面構造の模式図であ
る。FIG. 6 is a schematic view of a cross-sectional structure of a conventional single crystal growing furnace.
１ ＢＧＯ、２ 融液、３ 種結晶、４ 引上げ軸、５
白金製るつぼ、６、８ 耐火物、７ 白金製アフター
ヒーター、９ スペーサ、１０ 高周波コイル、２０
高周波加熱電源、２１ 電源制御機構、２２ 重量読取
り機構、２３回転速度制御機構、２４ 引上げ速度制御
機構、２５ コンピュータ、２６ 通信ケーブル、１０
０ 結晶育成炉。1 BGO, 2 melt, 3 seed crystal, 4 pulling axis, 5
Platinum crucible, 6, 8 refractory, 7 platinum after heater, 9 spacer, 10 high frequency coil, 20
High frequency heating power supply, 21 power supply control mechanism, 22 weight reading mechanism, 23 rotation speed control mechanism, 24 pulling speed control mechanism, 25 computer, 26 communication cable, 10
0 Crystal growth furnace.
Claims (6)
る単結晶育成炉と、前記単結晶育成炉に加熱用電力を供
給する加熱電源と、前記単結晶育成炉中の融液の液面に
垂直に接触させた軸をその中心軸周りに回転させながら
軸端面に被着した融液を単結晶として前記軸と共に引き
上げる引上げ機構と、この引き上げた単結晶の直径を算
出する直径算出手段と、前記算出された単結晶の直径に
応じて前記単結晶が目標直径に成長するまで単結晶の引
上げ速度と前記軸の回転速度、及び前記加熱電源の出力
を変化させる第１の制御手段と、前記単結晶が目標直径
に成長後、前記単結晶が目標長に達するまでは、前記引
上げ速度と前記回転速度を一定とし、前記供給する加熱
用電力のみを前記単結晶の直径の変化に応じて変化させ
る第２の制御手段とを備えたことを特徴とする単結晶の
製造装置。1. A single crystal growth furnace for heating a charged single crystal raw material to form a melt, a heating power supply for supplying electric power for heating to the single crystal growth furnace, and a heating power supply for the melt in the single crystal growth furnace. A pull-up mechanism that pulls up the melt adhered to the shaft end surface as a single crystal together with the shaft while rotating the shaft perpendicular to the liquid surface around its central axis, and a diameter calculator that calculates the diameter of the pulled single crystal. First control means for changing a pulling speed of the single crystal, a rotation speed of the shaft, and an output of the heating power source until the single crystal grows to a target diameter according to the calculated diameter of the single crystal. After the single crystal has grown to the target diameter, until the single crystal reaches the target length, the pulling speed and the rotation speed are kept constant, and only the supplied heating power is used to change the diameter of the single crystal. Second control means that changes according to An apparatus for producing a single crystal, comprising:
径が所定値以下の場合は前記引き上げ速度と回転速度を
一定値に設定すると共に、前記加熱電源の出力を一定値
で下げ、また、前記単結晶の直径が前記所定値以上で、
且つ、前記目標直径以下の場合は前記引き上げ速度と回
転速度を前記単結晶の直径に逆比例して下げると共に、
前記加熱電源の出力を結晶直径の増加に伴って増加する
ように制御することを特徴とする請求項１に記載の単結
晶の製造装置。2. The method according to claim 1, wherein when the diameter of the single crystal is equal to or less than a predetermined value, the first control means sets the pulling speed and the rotation speed to constant values, and lowers the output of the heating power supply at a constant value. Further, the diameter of the single crystal is not less than the predetermined value,
And, when the diameter is equal to or less than the target diameter, while reducing the pulling speed and the rotation speed in inverse proportion to the diameter of the single crystal,
The apparatus for producing a single crystal according to claim 1, wherein the output of the heating power supply is controlled so as to increase as the crystal diameter increases.
と回転速度を、前記単結晶の直径が前記所定値以下の場
合よりも低い引き上げ速度と回転速度で一定値に設定す
ると共に、前記加熱電源の出力を前記単結晶の直径の変
化に応じて制御することを特徴とする請求項１に記載の
単結晶の製造装置。3. The second control means sets the pulling speed and the rotation speed to constant values at a lower pulling speed and a lower rotation speed than when the diameter of the single crystal is equal to or less than the predetermined value. The apparatus for producing a single crystal according to claim 1, wherein an output of a power supply is controlled according to a change in a diameter of the single crystal.
端部に被着させ、その軸をその中心周りに所定の回転速
度で回転させながら引上げ機構により前記融液を単結晶
として引き上げる時、前記単結晶の単位時間当たりの重
量増加分から前記単結晶の直径を算出する第１の工程
と、前記単結晶が所定の直径に成長後、目標直径に成長
するまで前記単結晶の引上げ速度と回転速度、及び前記
単結晶育成炉の加熱量を前記単結晶の直径に応じて変化
させる第２の工程と、前記単結晶が目標直径に成長後、
前記単結晶が目標長に達するまでは、前記引上げ速度と
回転速度を一定として融液を前記引上げ機構で引き上
げ、前記単結晶育成炉の加熱量のみを前記単結晶の直径
の変化に応じて変化させる第３の工程とを備えことを特
徴とする単結晶の製造方法。4. A melt in a heated single crystal growing furnace is applied to an end of a shaft, and the melt is pulled by a pulling mechanism while rotating the shaft around a center thereof at a predetermined rotation speed. A first step of calculating a diameter of the single crystal from an increase in weight per unit time of the single crystal, and after growing the single crystal to a predetermined diameter, until the single crystal grows to a target diameter. A second step of changing a pulling speed and a rotation speed, and a heating amount of the single crystal growing furnace according to a diameter of the single crystal, and after the single crystal grows to a target diameter,
Until the single crystal reaches the target length, the melt is pulled up by the pulling mechanism while keeping the pulling speed and the rotation speed constant, and only the heating amount of the single crystal growing furnace is changed according to the change in the diameter of the single crystal. And a third step of producing the single crystal.
が所定値以下の場合は前記引き上げ速度と回転速度を一
定値に設定すると共に、前記加熱電源の出力を一定値で
下げ、また、前記単結晶の直径が前記所定値以上で、且
つ、前記目標直径以下の場合は前記引き上げ速度と回転
速度を前記単結晶の直径に逆比例して下げると共に、前
記加熱電源の出力をを結晶直径の増加に伴って増加する
ように制御することを特徴とする請求項４に記載の単結
晶の製造方法。5. In the second step, when the diameter of the single crystal is equal to or less than a predetermined value, the pulling speed and the rotation speed are set to constant values, and the output of the heating power source is reduced by a constant value. When the diameter of the single crystal is equal to or larger than the predetermined value and equal to or smaller than the target diameter, the pulling speed and the rotation speed are reduced in inverse proportion to the diameter of the single crystal, and the output of the heating power source is reduced. The method for producing a single crystal according to claim 4, wherein the control is performed so as to increase as the diameter increases.
と回転速度を、前記第２の工程において単結晶の直径が
所定値以下の場合よりも低い引き上げ速度と回転速度で
一定値に設定すると共に、前記加熱電源の出力を前記単
結晶の直径の変化に応じて制御することを特徴とする請
求項４に記載の単結晶の製造方法。6. In the third step, the pulling speed and the rotation speed are set to constant values at a lower pulling speed and rotation speed than when the diameter of the single crystal is equal to or less than a predetermined value in the second step. The method for producing a single crystal according to claim 4, wherein the output of the heating power source is controlled according to a change in the diameter of the single crystal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000078603A JP2001261485A (en) | 2000-03-21 | 2000-03-21 | Device and method for producing single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000078603A JP2001261485A (en) | 2000-03-21 | 2000-03-21 | Device and method for producing single crystal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001261485A true JP2001261485A (en) | 2001-09-26 |
Family
ID=18595991
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000078603A Pending JP2001261485A (en) | 2000-03-21 | 2000-03-21 | Device and method for producing single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001261485A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005054549A1 (en) * | 2003-12-04 | 2005-06-16 | Shin-Etsu Handotai Co., Ltd. | Silicon single crystal manufacturing system, silicon single crystal manufacturing method, and silicon single crystal |
| KR102064617B1 (en) | 2013-09-30 | 2020-01-09 | 에스케이실트론 주식회사 | Ingot growing controller and ingot growing control method for it |
-
2000
- 2000-03-21 JP JP2000078603A patent/JP2001261485A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005054549A1 (en) * | 2003-12-04 | 2005-06-16 | Shin-Etsu Handotai Co., Ltd. | Silicon single crystal manufacturing system, silicon single crystal manufacturing method, and silicon single crystal |
| KR102064617B1 (en) | 2013-09-30 | 2020-01-09 | 에스케이실트론 주식회사 | Ingot growing controller and ingot growing control method for it |
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