JP4833780B2 - Lid graphite crucible and silicon carbide single crystal growth apparatus - Google Patents

Lid graphite crucible and silicon carbide single crystal growth apparatus Download PDF

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JP4833780B2
JP4833780B2 JP2006255675A JP2006255675A JP4833780B2 JP 4833780 B2 JP4833780 B2 JP 4833780B2 JP 2006255675 A JP2006255675 A JP 2006255675A JP 2006255675 A JP2006255675 A JP 2006255675A JP 4833780 B2 JP4833780 B2 JP 4833780B2
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silicon carbide
graphite crucible
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弘志 柘植
昇 大谷
正和 勝野
辰雄 藤本
正史 中林
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Nippon Steel Corp
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本発明は、電子材料の基板に利用される大口径炭化珪素単結晶基板を作製するのに最適な蓋付き黒鉛坩堝及び結晶成長装置に関する。   The present invention relates to a graphite crucible with a lid and a crystal growth apparatus that are optimal for producing a large-diameter silicon carbide single crystal substrate used for a substrate of an electronic material.

高熱伝導率を持ち、バンドギャップの大きい炭化珪素単結晶は、高温で用いられる電子材料や、高耐圧の求められる電子材料の基板として有用な材料である。炭化珪素単結晶の作製法の一つに昇華再結晶法(レーリー法)がある。   A silicon carbide single crystal having high thermal conductivity and a large band gap is a useful material as a substrate for electronic materials used at high temperatures and electronic materials that require high breakdown voltage. One method for producing a silicon carbide single crystal is a sublimation recrystallization method (Rayleigh method).

昇華再結晶法は、2000℃を超える高温において炭化珪素粉末を昇華させ、その昇華ガスを低温部に再結晶化させることにより、炭化珪素結晶を製造する方法である。炭化珪素単結晶からなる種結晶を用いて、炭化珪素単結晶を製造する方法は、特に改良レーリー法と呼ばれ(非特許文献1)、バルク状の炭化珪素単結晶の製造に利用されている。改良レーリー法では、種結晶を用いているため結晶の核形成過程が制御でき、また不活性ガスにより雰囲気圧力を10Paから15kPa程度に制御することにより、結晶の成長速度等を再現性良くコントロールできる。一般に、原料と結晶の温度差を適切に制御して、炭化珪素単結晶の成長が行われている。得られた炭化珪素単結晶は基板としての規格の形状にするために、研削、切断、研磨といった加工が施され、電子材料の基板として利用される。   The sublimation recrystallization method is a method for producing a silicon carbide crystal by sublimating silicon carbide powder at a high temperature exceeding 2000 ° C. and recrystallizing the sublimation gas to a low temperature part. A method of manufacturing a silicon carbide single crystal using a seed crystal composed of a silicon carbide single crystal is called an improved Rayleigh method (Non-Patent Document 1), and is used for manufacturing a bulk silicon carbide single crystal. . The improved Rayleigh method uses a seed crystal to control the nucleation process of the crystal, and by controlling the atmospheric pressure from about 10 Pa to about 15 kPa with an inert gas, the crystal growth rate can be controlled with good reproducibility. . In general, a silicon carbide single crystal is grown by appropriately controlling a temperature difference between a raw material and a crystal. The obtained silicon carbide single crystal is subjected to processing such as grinding, cutting and polishing in order to obtain a standard shape as a substrate, and is used as a substrate for electronic materials.

炭化珪素単結晶はポリタイプと呼ばれる、いくつかの異なる結晶構造を有している。結晶成長中に異なるポリタイプが発生、成長すると、その部分で結晶欠陥が生じ、炭化珪素単結晶の電子デバイス用の基板としての品質が劣化する。そのため、ポリタイプの安定した炭化珪素単結晶成長方法が求められている。   Silicon carbide single crystals have several different crystal structures called polytypes. When different polytypes are generated and grow during crystal growth, crystal defects are generated in the portions, and the quality of the silicon carbide single crystal as a substrate for an electronic device is deteriorated. Therefore, there is a need for a polytype-stable silicon carbide single crystal growth method.

図1を用いて、改良レーリー法の原理を説明する。種結晶となる炭化珪素単結晶と原料となる炭化珪素結晶粉末(通常、アチソン(Acheson)法で作製された研磨材を洗浄・前処理したものが使用される)は、坩堝(通常黒鉛)の中に収納され、アルゴン等の不活性ガス雰囲気中(10Pa〜15kPa)で、原料を昇華させるために2000℃以上に加熱される。この際、原料粉末に比べ種結晶がやや低温になるように温度勾配が設定される。原料は昇華後、濃度勾配(温度勾配により形成される)により種結晶方向へ拡散、輸送される。単結晶成長は、種結晶に到着した原料ガスが種結晶上で再結晶化することにより実現される。   The principle of the improved Rayleigh method will be described with reference to FIG. The silicon carbide single crystal used as a seed crystal and the silicon carbide crystal powder used as a raw material (usually used after cleaning and pretreatment of an abrasive prepared by the Acheson method) are used for crucibles (usually graphite). It is stored in and heated to 2000 ° C. or higher in order to sublimate the raw material in an inert gas atmosphere such as argon (10 Pa to 15 kPa). At this time, the temperature gradient is set so that the seed crystal has a slightly lower temperature than the raw material powder. After sublimation, the raw material is diffused and transported in the direction of the seed crystal by a concentration gradient (formed by a temperature gradient). Single crystal growth is realized by recrystallization of the source gas that has arrived at the seed crystal on the seed crystal.

電子材料の基板として利用するために、口径の大きい結晶が求められている。口径の大きい結晶を成長させるためには、昇華再結晶を行うための坩堝も径の大きいものとすることが必要であり、原料の装填量を増やすために坩堝の高さも高くすることが必要である。   In order to be used as a substrate for an electronic material, a crystal having a large diameter is required. In order to grow a crystal with a large diameter, it is necessary that the crucible for performing sublimation recrystallization also has a large diameter, and it is necessary to increase the height of the crucible in order to increase the amount of raw material loaded. is there.

結晶成長用の坩堝は通常黒鉛材を加工して作製する。黒鉛坩堝に原料を装填し、種結晶を装着するために、坩堝は原料を装填する部分と、種結晶を装着する部分の少なくとも2つの部材から構成する必要がある。例えば、原料を装填する部分は円筒状の側壁と円盤状の底部から構成し、種結晶を装着する部分は円盤状の蓋として構成することができる。   A crucible for crystal growth is usually produced by processing a graphite material. In order to load a raw material into a graphite crucible and mount a seed crystal, the crucible needs to be composed of at least two members: a portion for loading the raw material and a portion for mounting the seed crystal. For example, the portion for loading the raw material can be constituted by a cylindrical side wall and a disc-shaped bottom portion, and the portion for mounting the seed crystal can be constituted by a disc-shaped lid.

坩堝が大きくなるに伴い、坩堝を一体物として製造した場合、原料を装填する作業や、種結晶を坩堝に固定する作業等において、坩堝が大きいために作業性が低下する問題がある。   As the crucible grows, when the crucible is manufactured as an integral product, there is a problem that workability is reduced due to the large crucible in the operation of loading raw materials, the operation of fixing the seed crystal to the crucible, and the like.

通常の結晶成長で採用されている減圧下で、炭化珪素が昇華して得られる昇華ガスの組成はSi、SiC2、Si2C等の組成を持ち、黒鉛坩堝と化学的な反応をしながら、種結晶部で再結晶し、結晶成長している(非特許文献1)。このことから、誘導加熱を用いて原料粉末を加熱するために利用している黒鉛坩堝は、結晶成長中に発生した昇華ガスによる化学反応に起因して侵食される。 The composition of the sublimation gas obtained by sublimation of silicon carbide under reduced pressure, which is used in normal crystal growth, has a composition such as Si, SiC 2 , Si 2 C, etc., while chemically reacting with the graphite crucible. In the seed crystal portion, recrystallization occurs and crystal growth occurs (Non-patent Document 1). For this reason, the graphite crucible used to heat the raw material powder using induction heating is eroded due to a chemical reaction caused by the sublimation gas generated during crystal growth.

昇華反応では固体がガスに変化するために、黒鉛坩堝内部の圧力は外部に比べて高くなる。このため、坩堝内外の圧力差に起因して、坩堝継ぎ手部分等の気密性の悪い部分で上記の化学反応が発生し、昇華ガスは黒鉛を侵食しながら坩堝の外側に流出する。   In the sublimation reaction, since the solid is changed to gas, the pressure inside the graphite crucible becomes higher than the outside. For this reason, due to the pressure difference between the inside and outside of the crucible, the above-described chemical reaction occurs in a portion having poor airtightness such as a crucible joint portion, and the sublimation gas flows out to the outside of the crucible while eroding the graphite.

長尺結晶を成長させるために、黒鉛坩堝を原料部分や種結晶装着部分等のいくつかの部分に分割して、結晶成長を行う方法は既に述べられている(特許文献1)。その中では、部分に分割した黒鉛を、坩堝として組み上げるために、(1)ねじ込み式、(2)すり合わせ式、(3)嵌め込み式等の形式が述べられている。   In order to grow a long crystal, a method for crystal growth by dividing a graphite crucible into several parts such as a raw material part and a seed crystal mounting part has already been described (Patent Document 1). Among them, in order to assemble the graphite divided into parts as a crucible, (1) screw-in type, (2) sliding type, (3) fitting type, etc. are described.

黒鉛坩堝は、誘導加熱を用いて高温にするために、その周囲を黒鉛の断熱材を用いて包んでいる。特許文献1にあるように、組み上げ式の坩堝とした場合、上記のように炭化珪素が昇華することに伴い、坩堝内部の圧力が上昇し、昇華ガスが坩堝内部から接続部を通じて流出する。流出した昇華ガスは、黒鉛坩堝周囲に配置した断熱材部分で再結晶し、断熱性を劣化させる。このために、誘導加熱により原料部分を昇華温度まで十分に加熱できないという問題が生じる。また、成長中に断熱材が劣化することで、坩堝内部の温度制御が難しくなり、ポリタイプの安定した加熱条件を得ることが難しくなるという問題も生じる。   The graphite crucible is wrapped with a graphite heat insulating material in order to increase the temperature using induction heating. As described in Patent Document 1, when an assembled crucible is used, the pressure inside the crucible rises as the silicon carbide sublimates as described above, and the sublimation gas flows out from the crucible through the connection portion. The sublimated gas that has flowed out is recrystallized at a heat insulating material portion arranged around the graphite crucible, and deteriorates the heat insulating property. For this reason, the problem that a raw material part cannot fully be heated to sublimation temperature by induction heating arises. In addition, since the heat insulating material deteriorates during growth, it becomes difficult to control the temperature inside the crucible, and it becomes difficult to obtain stable heating conditions of the polytype.

特に、75mm以上の口径の大きい炭化珪素単結晶を作製する際には、坩堝の口径が大きくなり、原料の装填量は増大する。それに伴い、昇華ガスの発生量は特許文献1の実施例の大きさのインゴットを作製する場合に比べて増大し、接合部を通じて外部に流出する昇華ガスの量も増える。流出した昇華ガスが断熱材部で再結晶化すると、断熱材が劣化し、結晶成長時の黒鉛坩堝の温度制御性が低下し、良質の大口径炭化珪素単結晶が得られないという問題が発生する。
特開平3-295898号公報 Yu. M. Tairov and V. F. Tsvetkov, Journal of Crystal Growth, 52 (1981) pp.146
In particular, when producing a silicon carbide single crystal having a large diameter of 75 mm or more, the diameter of the crucible becomes large and the amount of raw material charged increases. Accordingly, the amount of sublimation gas generated is increased as compared with the case of producing an ingot having the size of the embodiment of Patent Document 1, and the amount of sublimation gas flowing out through the joint portion is also increased. When the sublimated gas that flows out is recrystallized in the heat insulating material, the heat insulating material deteriorates, the temperature controllability of the graphite crucible during crystal growth deteriorates, and a problem arises in that a high-quality large-diameter silicon carbide single crystal cannot be obtained. To do.
JP-A-3-295898 Yu. M. Tairov and VF Tsvetkov, Journal of Crystal Growth, 52 (1981) pp.146

本発明では、種結晶を用いた改良型レーリー法を用いて炭化珪素単結晶を作製するのに適した組立て型の黒鉛坩堝を開示することで、黒鉛坩堝周囲の断熱材の劣化や、坩堝内部の圧力変動に起因した結晶欠陥の発生を抑制し、ポリタイプの安定した結晶成長を可能とし、高品質の炭化珪素単結晶が得られるようにすることを目的とする。   In the present invention, by disclosing an assembled graphite crucible suitable for producing a silicon carbide single crystal using an improved Rayleigh method using a seed crystal, deterioration of the heat insulating material around the graphite crucible, It is an object of the present invention to suppress the generation of crystal defects due to pressure fluctuations of the above, to enable stable crystal growth of a polytype, and to obtain a high-quality silicon carbide single crystal.

2以上の黒鉛坩堝部材を組立ててなる炭化珪素単結晶成長用蓋付き黒鉛坩堝であって、黒鉛坩堝の内径が75mm以上であり、少なくとも該黒鉛坩堝内に充填される炭化珪素原料から20mm以内に位置する2つの黒鉛坩堝部材の接続部は、一方の黒鉛坩堝部材に形成された雄ねじと、他方の黒鉛坩堝部材に形成された雌ねじとを螺合させた長さ5mm以上40mm以下のねじ部からなることを特徴とする蓋付き黒鉛坩堝を用いることで、ポリタイプの安定した結晶成長が可能となり、結晶性の良い炭化珪素単結晶が得られる。   A graphite crucible with a silicon carbide single crystal growth lid formed by assembling two or more graphite crucible members, wherein the graphite crucible has an inner diameter of 75 mm or more, and at least within 20 mm from the silicon carbide raw material filled in the graphite crucible The connecting portion between the two graphite crucible members positioned from a screw portion having a length of 5 mm or more and 40 mm or less in which a male screw formed on one graphite crucible member and a female screw formed on the other graphite crucible member are screwed together. By using a graphite crucible with a lid characterized by the above, stable crystal growth of a polytype becomes possible, and a silicon carbide single crystal with good crystallinity is obtained.

また、黒鉛坩堝部材同士の全ての接続部は、一方の黒鉛坩堝部材に形成された雄ねじと、他方の黒鉛坩堝部材に形成された雌ねじとを螺合させたねじ部からなる蓋付き黒鉛坩堝を用いることで、ポリタイプの安定した結晶成長が可能となり、結晶性の良い炭化珪素単結晶が得られる。   Further, all the connecting portions between the graphite crucible members are made of a graphite crucible with a lid formed by a screw portion in which a male screw formed on one graphite crucible member and a female screw formed on the other graphite crucible member are screwed together. By using it, stable crystal growth of a polytype becomes possible, and a silicon carbide single crystal with good crystallinity can be obtained.

さらに、前記該黒鉛坩堝内に充填される炭化珪素原料から20mm以内に位置する接続部以外の少なくとも1箇所の接続部のねじ部の長さが、炭化珪素原料から20mm以内に位置する接続部のねじ部の長さより短いも前記の蓋付き黒鉛坩堝を用いることで、ポリタイプの安定した結晶成長が可能となり、結晶性の良い炭化珪素単結晶が得られる。   Further, the length of the threaded portion of at least one connecting portion other than the connecting portion located within 20 mm from the silicon carbide raw material filled in the graphite crucible is a connecting portion located within 20 mm from the silicon carbide raw material. By using the above graphite crucible with a lid, which is shorter than the length of the threaded portion, stable polytype crystal growth becomes possible, and a silicon carbide single crystal with good crystallinity can be obtained.

前記の蓋付き黒鉛坩堝を少なくとも用いてなる炭化珪素単結晶成長装置を用いることで、ポリタイプの安定した結晶成長が可能となり、結晶性の良い炭化珪素単結晶が得られる。   By using a silicon carbide single crystal growth apparatus using at least the above graphite crucible with a lid, stable crystal growth of a polytype becomes possible, and a silicon carbide single crystal with good crystallinity is obtained.

本発明における蓋付き黒鉛坩堝は、黒鉛坩堝部材を少なくとも2以上用いて組立てることによって形成する。ここで、2つの黒鉛坩堝部材をつなぎ合わせた部分が接続部である。黒鉛坩堝を形成する黒鉛坩堝部材の構成については特に制限されず、適宜設計可能であるが、例えばその一例を示せば蓋部、側壁部及び底部の各黒鉛坩堝部材を組立てて黒鉛坩堝を形成するようにしてもよい。或いは、上記側壁部を更に炭化珪素原料が装填される原料側壁部と結晶が成長する成長空間側壁部とに分割するようにしてもよい。また、黒鉛坩堝内に充填される炭化珪素原料から20mm以内に位置する接続部とは、2つの黒鉛坩堝部材に形成された雄ねじと雌ねじとが螺合した箇所(ねじ部)から黒鉛坩堝内に充填される炭化珪素原料までの最短距離が20mm以内である接続部を言う。   The graphite crucible with a lid in the present invention is formed by assembling using at least two graphite crucible members. Here, the portion where two graphite crucible members are joined together is the connection portion. The structure of the graphite crucible member for forming the graphite crucible is not particularly limited and can be designed as appropriate. For example, the graphite crucible member is assembled by assembling the graphite crucible members of the lid portion, the side wall portion, and the bottom portion. You may do it. Or you may make it divide | segment the said side wall part into the raw material side wall part with which a silicon carbide raw material is further loaded, and the growth space side wall part in which a crystal grows. In addition, the connection portion located within 20 mm from the silicon carbide raw material filled in the graphite crucible means that the male screw and the female screw formed on the two graphite crucible members are screwed into the graphite crucible. The shortest distance to the silicon carbide raw material to be filled is a connection portion within 20 mm.

本発明によれば、組立て型黒鉛坩堝を用いて、種結晶を用いた改良型レーリー法により、結晶成長中に黒鉛坩堝の周囲を取り囲む黒鉛断熱材の劣化を抑制することができ、成長中の坩堝内部の温度制御性を向上させることができる。その結果、ポリタイプの安定した成長を行うことが可能となり、特に大口径のインゴットの製造歩留まり及びこれから得られる炭化珪素単結晶基板の製造歩留まりを大幅に改善することができる。   According to the present invention, it is possible to suppress deterioration of the graphite heat insulating material surrounding the periphery of the graphite crucible during crystal growth by an improved Rayleigh method using a seed crystal using an assembled graphite crucible. The temperature controllability inside the crucible can be improved. As a result, it is possible to perform stable growth of the polytype, and in particular, it is possible to greatly improve the production yield of large-diameter ingots and the production yield of silicon carbide single crystal substrates obtained therefrom.

黒鉛坩堝を組立て型の坩堝として構成することで、坩堝の原材料コストの削減が図れると共に、作業性を向上させることができる。例えば、原料を装填する部分を一体として作製した場合には、原料を装填する部分(原料装填部)の黒鉛が削り取られて無駄になってしまう。一方で、本発明によれば、黒鉛坩堝を組立て型として構成することで、例えば原料装填部を側壁部と底部とに分けて作製し、2つの部材を組み合わせて原料装填部を構成することができる。側壁部の円筒部を作製するためにくりぬかれた円筒内部の黒鉛部材は、径の小さい部材の原材料として活用できる。その結果、黒鉛原材料の利用効率を向上させることができ、坩堝のコストの低減が行える。特に口径が75mm以上の口径の大きい結晶を作製する際には、成長を行うための黒鉛坩堝も大きいため、一体物として黒鉛坩堝を作製すると黒鉛原材料の利用効率が低下するが、組立て型として構成することで利用効率の向上が図れる。   By configuring the graphite crucible as an assembly-type crucible, the raw material cost of the crucible can be reduced and workability can be improved. For example, in the case where the part to be charged with the raw material is manufactured as one body, the graphite in the part to be loaded with the raw material (raw material loading part) is scraped off and is wasted. On the other hand, according to the present invention, by configuring the graphite crucible as an assembly mold, for example, the raw material loading portion can be divided into a side wall portion and a bottom portion, and the raw material loading portion can be configured by combining two members. it can. The graphite member inside the cylinder hollowed out to produce the cylindrical portion of the side wall portion can be used as a raw material for a member having a small diameter. As a result, the utilization efficiency of the graphite raw material can be improved, and the cost of the crucible can be reduced. In particular, when producing a crystal with a large diameter of 75 mm or more, the graphite crucible for growth is also large, so if the graphite crucible is produced as an integral piece, the utilization efficiency of the graphite raw material decreases, but it is configured as an assembly type By doing so, the utilization efficiency can be improved.

以下、図を基に本発明による実施の形態を説明する。図2に本発明が開示する炭化珪素単結晶成長のための坩堝の構造を示す。この例では、坩堝は、蓋部、成長空間側壁部、原料側壁部、及び底部の4つの黒鉛坩堝部材からなる。
図2は一つの例であり、本発明では、黒鉛坩堝部材の個数を、2個、3個もしくは5個以上に分割することも含む。
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows the structure of a crucible for growing a silicon carbide single crystal disclosed in the present invention. In this example, the crucible includes four graphite crucible members, which are a lid, a growth space side wall, a raw material side wall, and a bottom.
FIG. 2 shows an example, and the present invention includes dividing the number of graphite crucible members into two, three, or five or more.

原料側壁部と底部とをつなぐ接続部3は、原料に直接接する部分(原料からの距離が0mm)である。このように、接続部が原料から20mm以内にある場合には、この接続部の温度は原料部分とほぼ同程度の温度に加熱されている。このため、非特許文献1にあるように、炭化珪素昇華ガスと黒鉛坩堝は化学的な反応を起こし、昇華ガスとの化学反応により接続部を構成する黒鉛坩堝部材が侵食され易くなる。その結果、結晶成長時に坩堝内部で発生する昇華ガスが、坩堝内外の圧力差に起因して接続部3を通って坩堝の外側に流出し、坩堝外側に配置した断熱材の部分で炭化珪素が再結晶化して、断熱材の劣化を引き起こすおそれがある。このため、成長中の温度制御性が悪くなり、ポリタイプの安定した成長が得られなくなる。   The connecting portion 3 that connects the raw material side wall and the bottom is a portion that directly contacts the raw material (the distance from the raw material is 0 mm). As described above, when the connecting portion is within 20 mm from the raw material, the temperature of the connecting portion is heated to substantially the same temperature as the raw material portion. For this reason, as described in Non-Patent Document 1, the silicon carbide sublimation gas and the graphite crucible cause a chemical reaction, and the graphite crucible member constituting the connection portion is easily eroded by the chemical reaction with the sublimation gas. As a result, the sublimation gas generated inside the crucible during crystal growth flows out of the crucible through the connection part 3 due to the pressure difference between the inside and outside of the crucible, and silicon carbide is formed at the portion of the heat insulating material arranged outside the crucible. Recrystallization may cause deterioration of the heat insulating material. For this reason, the temperature controllability during growth deteriorates, and stable growth of the polytype cannot be obtained.

特に、75mm以上の口径の大きい炭化珪素単結晶を作製する際には、坩堝の口径が大きくなると同時に原料の装填量も増大し、昇華ガスの発生量は増大する。その結果、原料から20mm以内の距離にある接続部を通じて、坩堝内部から外部へ流出する昇華ガスの量が増大し、断熱材の劣化を引き起こし、ポリタイプの安定した成長が得られなくなる。   In particular, when a silicon carbide single crystal having a large diameter of 75 mm or more is produced, the diameter of the crucible increases and the amount of raw material charged increases, and the amount of sublimation gas generated increases. As a result, the amount of sublimation gas flowing out from the inside of the crucible through the connecting portion within a distance of 20 mm from the raw material increases, causing deterioration of the heat insulating material, and stable growth of the polytype cannot be obtained.

本発明者らは、口径が75mm以上の大口径の炭化珪素単結晶を作製する際に利用する内径が75mm以上の組立て型の黒鉛坩堝において、原料からの距離が20mm以内の接続部を5mm以上の長さ(深さ)のねじ部によって形成することで、接続部の気密性を向上させ、この部分から坩堝外部に流出する昇華ガスの量を少なくし、断熱材の劣化を少なくすることができることを見出した。この結果、温度制御性が良く、ポリタイプの安定した成長条件を得ることができ、結晶性の良い炭化珪素単結晶が得られる。この接続部のねじ部の長さが40mmより長い場合にも、昇華ガスが坩堝外部に流出し難いという効果は得られるが、ねじを締める作業の効率性が悪くなることと、40mmの長さがあれば、上記の効果が飽和することから、接続部を形成するねじ部の長さは5mm以上40mm以下が適切である。また、現状で目標とされている結晶の口径が150mm程度であることや、作業性を考えると、原料部の内径は200mm以下であることが好ましい。   The inventors of the present invention have an assembly type graphite crucible having an inner diameter of 75 mm or more used for producing a large-diameter silicon carbide single crystal having a diameter of 75 mm or more. It is possible to improve the airtightness of the connection part by reducing the amount of sublimation gas flowing out from this part to the outside of the crucible and to reduce the deterioration of the heat insulating material. I found out that I can do it. As a result, the temperature controllability is good, the stable growth conditions of the polytype can be obtained, and a silicon carbide single crystal with good crystallinity can be obtained. Even if the length of the threaded portion of this connection is longer than 40 mm, the effect that the sublimation gas does not easily flow out of the crucible can be obtained, but the efficiency of tightening the screw becomes worse, and the length of 40 mm If there is, the above effect is saturated, so the length of the threaded portion forming the connecting portion is suitably 5 mm or more and 40 mm or less. In addition, considering the current target crystal diameter of about 150 mm and workability, the raw material portion preferably has an inner diameter of 200 mm or less.

接続部が、原料から20mmより遠いところにある場合には、この接続部の温度は原料部分に比べて低い。このため、昇華ガスと黒鉛坩堝の化学的な反応は温度の指数関数で減少し、昇華ガスとの化学反応により接続部を構成する黒鉛坩堝部材が侵食される程度は低減され、坩堝外部へ流出するガスの量は少ない。その結果、周囲を囲む断熱材の劣化も小さく、温度制御性に問題が生じることは無く、ポリタイプの比較的安定した成長条件を得ることができる。そこで、原料から20mmより遠い接続部は、すり合わせ式、嵌め込み式、ねじ式等のつなぎ方で接続することができる。   In the case where the connecting portion is farther than 20 mm from the raw material, the temperature of the connecting portion is lower than that of the raw material portion. For this reason, the chemical reaction between the sublimation gas and the graphite crucible decreases with an exponential function of temperature, and the degree of erosion of the graphite crucible member constituting the connection portion due to the chemical reaction with the sublimation gas is reduced and flows out of the crucible. The amount of gas to be produced is small. As a result, the deterioration of the heat insulating material surrounding the surroundings is small, there is no problem in temperature controllability, and a relatively stable growth condition of the polytype can be obtained. Therefore, the connection part farther than 20 mm from the raw material can be connected by a connecting method such as a sliding type, a fitting type, a screw type, or the like.

例えば、図2に示した接続部1や接続部2が原料から20mm以内の距離にある場合には、上記の原料からの距離が20mm以内にある接続部3と同様の理由により、この接続部から坩堝外部への昇華ガスの流出を防ぐために、その接続部は、長さは5mm以上40mm以下のねじ部で形成することが適切である。   For example, when the connecting portion 1 and the connecting portion 2 shown in FIG. 2 are within a distance of 20 mm from the raw material, this connecting portion is for the same reason as the connecting portion 3 whose distance from the raw material is within 20 mm. In order to prevent the sublimation gas from flowing out of the crucible to the outside of the crucible, it is appropriate to form the connecting portion with a screw portion having a length of 5 mm or more and 40 mm or less.

接続部が、ねじ部で形成されていない場合、例えば、黒鉛坩堝部材をすり合わせや嵌め込み方式で坩堝を構成した場合、結晶成長時に生じる昇華反応により坩堝内部の圧力が上昇すると、この内部の圧力上昇を緩和するために、継ぎ手部分で黒鉛坩堝部材同士が移動し隙間を形成し、坩堝内外部の圧力を同じにするような動きが生じる。結晶成長中に坩堝部材が動くと、坩堝内部の温度分布が変化し、ポリタイプの安定した成長が得られなくなる。また、隙間が生じることで、隙間が生じた瞬間に坩堝内部の圧力が大きく変動し、安定な結晶成長が行えない。   When the connecting part is not formed of a threaded part, for example, when the crucible is configured by fitting or fitting a graphite crucible member, if the pressure inside the crucible rises due to a sublimation reaction that occurs during crystal growth, the internal pressure rises. In order to alleviate this, the graphite crucible members move at the joint portion to form a gap, and a movement occurs to make the pressure inside and outside the crucible the same. If the crucible member moves during crystal growth, the temperature distribution inside the crucible changes, and stable growth of the polytype cannot be obtained. Further, since the gap is generated, the pressure inside the crucible greatly fluctuates at the moment when the gap is generated, and stable crystal growth cannot be performed.

本発明者らは、好ましくは黒鉛坩堝部材の接続部を全てねじ部で形成することにより、結晶成長中に坩堝部材が移動することに起因した坩堝内部の温度分布や圧力の変化を抑制することが可能であり、より確実にポリタイプの安定した成長を行うことができることを見出した。   The present inventors preferably suppress all changes in temperature distribution and pressure inside the crucible due to the movement of the crucible member during crystal growth by forming all the connecting portions of the graphite crucible member with screw portions. It was found that it is possible to perform stable growth of polytypes more reliably.

原料から20mm以内に位置する接続部以外の少なくとも1箇所の接続部を形成するねじ部の長さを、原料から20mm以内に位置する接続部のねじ部の長さより短くすることで、原料部から20mm以内の接続部に比べて、原料部から20mmより遠いところにある接続部の気密性を下げることができる。原料部に近い接続部から坩堝外部に流出するガスは、炭化珪素昇華ガスを多く含んでおり、坩堝外部に流出した際に、周囲の断熱材を劣化させる。一方で、原料部から20mmより遠いところにある接続部から坩堝外部に流出するガスは、結晶装置内に充填されている不活性ガスによって薄められているために、炭化珪素昇華ガスの成分が少なくなっている。このため、原料から20mmより遠いところにある接続部から坩堝内部のガスを流出させても、周囲の断熱材の劣化は原料部から20mm以内にある接続部からの流出に比べれば程度が軽い。   By making the length of the screw part that forms at least one connection part other than the connection part located within 20 mm from the raw material shorter than the length of the screw part of the connection part located within 20 mm from the raw material, Compared with a connection part within 20 mm, the airtightness of the connection part farther than 20 mm from the raw material part can be lowered. The gas flowing out of the crucible from the connection part close to the raw material part contains a large amount of silicon carbide sublimation gas, and when it flows out of the crucible, the surrounding heat insulating material is deteriorated. On the other hand, the gas flowing out of the crucible from the connection part farther than 20 mm from the raw material part is diluted with an inert gas filled in the crystal device, so that the silicon carbide sublimation gas component is small. It has become. For this reason, even if the gas inside the crucible is caused to flow out from the connection part farther than 20 mm from the raw material, the deterioration of the surrounding heat insulating material is lighter than that from the connection part within 20 mm from the raw material part.

このことから、本発明者らは、原料から20mm以内に位置する接続部以外の少なくとも1箇所の接続部を形成するねじ部の長さを、原料から20mm以内に位置する接続部を形成するねじ部の長さより短くすることで、原料から遠い接続部からガスを意図的に坩堝外部に少量流出させ、坩堝内外の圧力差を低下させ、原料に近い接続部から流出するガスの量を少なくすることができ、このことにより、周囲の断熱材の劣化を抑制することができ、成長中の温度制御性を向上させることができ、ポリタイプの安定した結晶成長が得られることを見出した。   From this, the present inventors have determined the length of the screw part forming at least one connection part other than the connection part located within 20 mm from the raw material, and the screw forming the connection part located within 20 mm from the raw material. By making it shorter than the length of the part, a small amount of gas is intentionally flown out of the crucible from the connection part far from the raw material, the pressure difference inside and outside the crucible is reduced, and the amount of gas flowing out from the connection part close to the raw material is reduced It has been found that this makes it possible to suppress deterioration of the surrounding heat insulating material, improve temperature controllability during growth, and obtain stable polytype crystal growth.

上記の黒鉛坩堝やそれを用いた結晶製造装置を用いて作製した炭化珪素単結晶インゴットは、単一ポリタイプからなる高品質のインゴットとなる。また、このインゴットを切断、研磨して作製した炭化珪素単結晶基板は欠陥が少なく、電子材料用の基板として有用である。   A silicon carbide single crystal ingot produced using the above graphite crucible or a crystal production apparatus using the graphite crucible becomes a high quality ingot made of a single polytype. In addition, a silicon carbide single crystal substrate manufactured by cutting and polishing the ingot has few defects and is useful as a substrate for an electronic material.

以下に、本発明の実施例について述べる。
まず、実施例で用いる単結晶成長装置全体について図3を用いて簡単に説明する。結晶成長は、炭化珪素結晶粉末2を昇華させ、種結晶として用いた炭化珪素単結晶1上で再結晶化させることにより行われる。二重石英管5は、真空排気装置11により高真空排気(10-3Pa以下)することができ、かつ高純度Arガス配管9と高純度Arガス用マスフローコントローラ10を用いて、内部雰囲気をArガスにより圧力制御することができる。また、二重石英管5の外周には、ワークコイル8が設置されており、高周波電流を流すことにより黒鉛製坩堝3を加熱し、原料及び種結晶を所望の温度に加熱することができる。坩堝温度の計測は、坩堝上下部を覆うフェルトの中央部に直径2〜4mmの光路を設け坩堝上部及び下部からの光を取り出し、二色温度計を用いて行う。坩堝下部の温度を原料温度、坩堝上部の温度を種温度とする。
Examples of the present invention will be described below.
First, the entire single crystal growth apparatus used in the examples will be briefly described with reference to FIG. Crystal growth is performed by sublimating the silicon carbide crystal powder 2 and recrystallizing it on the silicon carbide single crystal 1 used as a seed crystal. The double quartz tube 5 can be highly evacuated (10 -3 Pa or less) by the evacuation device 11, and the internal atmosphere can be changed using the high purity Ar gas pipe 9 and the mass flow controller 10 for high purity Ar gas. The pressure can be controlled by Ar gas. A work coil 8 is provided on the outer periphery of the double quartz tube 5, and the graphite crucible 3 can be heated by flowing a high-frequency current to heat the raw material and the seed crystal to a desired temperature. The temperature of the crucible is measured using a two-color thermometer by providing an optical path with a diameter of 2 to 4 mm at the center of the felt covering the upper and lower parts of the crucible and extracting light from the upper and lower parts of the crucible. The temperature at the bottom of the crucible is the raw material temperature, and the temperature at the top of the crucible is the seed temperature.

結晶成長は以下のように行った。種結晶を取り付け、原料を装填した黒鉛製坩堝3は、二重石英管5の内部に、黒鉛の支持棒6により設置した。黒鉛製坩堝3の周囲には、熱シールドのための黒鉛製断熱材7を設置した。その後に、石英管の内部を真空排気し、ワークコイルに電流を流し、原料温度を2000℃まで上げた。その後、雰囲気ガスとして高純度Arガスを流入させ、石英管内圧力を約80kPaに保ちながら、原料温度を目標温度である2400℃まで上昇させた。成長圧力である1.3kPaには30分かけて減圧し、その後、結晶成長を開始した。所定の成長時間の間、原料温度を目標温度に保持し、その後、4時間かけてワークコイルに流す電流の値を0とした。   Crystal growth was performed as follows. A graphite crucible 3 to which a seed crystal was attached and a raw material was loaded was set inside a double quartz tube 5 by a support rod 6 made of graphite. Around the graphite crucible 3, a graphite heat insulating material 7 for heat shield was installed. Thereafter, the inside of the quartz tube was evacuated, current was passed through the work coil, and the raw material temperature was raised to 2000 ° C. Thereafter, high-purity Ar gas was introduced as the atmospheric gas, and the raw material temperature was raised to the target temperature of 2400 ° C. while maintaining the pressure in the quartz tube at about 80 kPa. The growth pressure was reduced to 1.3 kPa over 30 minutes, and then crystal growth was started. During the predetermined growth time, the raw material temperature was maintained at the target temperature, and then the value of the current passed through the work coil was set to 0 over 4 hours.

(実施例1)
次に、本発明で開示した黒鉛坩堝を利用して、炭化珪素単結晶を製造した実施例について説明する。図4にあるように、蓋部、側壁部、及び底部の3つの黒鉛坩堝部材からなる黒鉛坩堝を組立てて作製した。坩堝の外形は120mm、原料が装填される部分の内径は75mmとした。底部と側壁部とをつなぐ接続部2は、底部に形成された雄ねじと側壁部に形成された雌ねじとを螺合させた長さ5mmのねじ部で形成した。上記雄ねじと雌ねじはJIS規格に則り、径が100mm、ピッチが1mmとした。尚、この接続部2は原料から20mm以内に位置する。
一方、接続部1は原料から20mm以上離れた部分に配置した。接続部1は嵌め込み式とした。
(Example 1)
Next, an example in which a silicon carbide single crystal is manufactured using the graphite crucible disclosed in the present invention will be described. As shown in FIG. 4, a graphite crucible composed of three graphite crucible members of a lid part, a side wall part, and a bottom part was assembled and produced. The outer diameter of the crucible was 120 mm, and the inner diameter of the portion charged with the raw material was 75 mm. The connecting part 2 connecting the bottom part and the side wall part was formed by a thread part having a length of 5 mm in which a male screw formed on the bottom part and a female screw formed on the side wall part were screwed together. The male screw and female screw were 100 mm in diameter and 1 mm in pitch according to JIS standards. The connecting portion 2 is located within 20 mm from the raw material.
On the other hand, the connecting part 1 was arranged at a part separated by 20 mm or more from the raw material. The connecting part 1 is a fitting type.

まず、種結晶として口径75mmの(0001)面を有した4Hポリタイプの炭化珪素単結晶ウェハを用意し、蓋部に取り付けた。側壁部と底部とを互いにねじで組み合わせ、その内部にアチソン法により作製された炭化珪素結晶原料粉末を装填した。最後に、種結晶を取り付けた蓋部を側壁部に嵌め込むことにより、炭化珪素単結晶成長用坩堝を組み上げた。この坩堝を、上に述べたように、支持台の上に載せ、50時間結晶成長を行った。   First, a 4H polytype silicon carbide single crystal wafer having a (0001) plane with a diameter of 75 mm was prepared as a seed crystal, and attached to the lid. The side wall portion and the bottom portion were combined with each other with a screw, and the silicon carbide crystal raw material powder produced by the Atchison method was loaded therein. Finally, a silicon carbide single crystal growth crucible was assembled by fitting a lid portion to which a seed crystal was attached into the side wall portion. As described above, this crucible was placed on a support base and crystal growth was performed for 50 hours.

得られた結晶の口径は77mm程度で高さは30mm程度であった。成長速度は約0.6mm/時であった。こうして得られた炭化珪素単結晶をX線回折及びラマン散乱を用いて分析したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶であることが確認された。この炭化珪素単結晶インゴットを研削、切断、研磨して炭化珪素単結晶基板を作製したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶の基板が作製できた。炭化珪素単結晶基板上に電子デバイスを作製する場合、基板に存在する欠陥が電子デバイスの特性に影響を与えるため、本発明により得られた欠陥の少ない高品質の炭化珪素単結晶基板は、電子デバイスを作製するための基板として有用である。   The diameter of the obtained crystal was about 77 mm and the height was about 30 mm. The growth rate was about 0.6 mm / hour. When the silicon carbide single crystal thus obtained was analyzed using X-ray diffraction and Raman scattering, it was confirmed that the silicon carbide single crystal was a high-quality silicon carbide single crystal consisting of a single polytype of 4H and having few defects. When this silicon carbide single crystal ingot was ground, cut, and polished to produce a silicon carbide single crystal substrate, a high-quality silicon carbide single crystal substrate consisting of a single polytype of 4H was produced. When producing an electronic device on a silicon carbide single crystal substrate, defects existing in the substrate affect the characteristics of the electronic device. Therefore, the high-quality silicon carbide single crystal substrate obtained by the present invention has few defects. It is useful as a substrate for manufacturing a device.

(実施例2)
図5にあるように、蓋部、成長空間側壁部、原料側壁部、及び底部の4つの黒鉛坩堝部材からなる坩堝を組立てて作製した。坩堝の外形は130mm、原料が装填される部分の内径は110mmとした。底部と原料側壁部とをつなぐ接続部3は、底部に形成された雄ねじと原料側壁部に形成された雌ねじとを螺合させた長さ15mmのねじ部で形成した。上記雄ねじと雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。原料側壁部と成長空間側壁部とをつなぐ接続部2は原料から15mm離れた部分に配置した。接続部2は長さ10mmのねじ部で形成した。上記雄ねじと雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。成長空間側壁部と蓋部とをつなぐ接続部1は原料から20mm以上離れた位置に配置した。接続部1は長さ5mmのねじ部で形成した。上記雄ねじと雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。
(Example 2)
As shown in FIG. 5, a crucible composed of four graphite crucible members including a lid, a growth space side wall, a raw material side wall, and a bottom was assembled. The outer diameter of the crucible was 130 mm, and the inner diameter of the portion charged with the raw material was 110 mm. The connecting portion 3 that connects the bottom and the raw material side wall was formed by a 15 mm long screw portion in which a male screw formed on the bottom and a female screw formed on the raw material side wall were screwed together. The male screw and female screw were compliant with JIS standards and had a diameter of 115 mm and a pitch of 1 mm. The connecting portion 2 connecting the raw material side wall and the growth space side wall was disposed at a portion 15 mm away from the raw material. The connection part 2 was formed by a screw part having a length of 10 mm. The male screw and female screw were compliant with JIS standards and had a diameter of 115 mm and a pitch of 1 mm. The connecting portion 1 connecting the growth space side wall portion and the lid portion was disposed at a position separated from the raw material by 20 mm or more. The connecting part 1 was formed by a thread part having a length of 5 mm. The male screw and female screw were compliant with JIS standards and had a diameter of 115 mm and a pitch of 1 mm.

まず、種結晶として口径76mmの(0001)面を有した4Hポリタイプの炭化珪素単結晶ウェハを用意し、蓋部に取り付けた。次に、種結晶を取り付けた蓋部と成長空間側壁部とを互いにねじで組み合わせて固定した。原料側壁部と底部とについても互いにねじで組み合わせ、その内部にCVD法により作製された高純度炭化珪素結晶原料粉末を装填した。最後に、原料側壁部と成長空間側壁部とを互いにねじで組み合わせて固定することで、炭化珪素単結晶成長用坩堝を組み上げた。この坩堝を、上に述べたように、支持台の上に載せ、60時間結晶成長を行った。   First, a 4H polytype silicon carbide single crystal wafer having a (0001) plane with a diameter of 76 mm was prepared as a seed crystal, and attached to the lid. Next, the lid portion to which the seed crystal was attached and the growth space side wall portion were fixed together by screws. The raw material side wall portion and the bottom portion were also combined with each other with screws, and high purity silicon carbide crystal raw material powder produced by a CVD method was loaded therein. Finally, the silicon carbide single crystal growth crucible was assembled by fixing the raw material side wall portion and the growth space side wall portion together with screws. As described above, this crucible was placed on a support base and crystal growth was performed for 60 hours.

得られた結晶の口径は80mm程度で、高さは50mm程度であった。成長速度は約0.8mm/時であった。こうして得られた炭化珪素単結晶をX線回折及びラマン散乱を用いて分析したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶であることが確認された。この炭化珪素単結晶インゴットを研削、切断、研磨して炭化珪素単結晶基板を作製したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶の基板が作製できた。炭化珪素単結晶基板上に電子デバイスを作製する場合、基板に存在する欠陥が電子デバイスの特性に影響を与えるため、本発明により得られた欠陥の少ない高品質の炭化珪素単結晶基板は、電子デバイスを作製するための基板として有用である。   The diameter of the obtained crystal was about 80 mm, and the height was about 50 mm. The growth rate was about 0.8 mm / hour. When the silicon carbide single crystal thus obtained was analyzed using X-ray diffraction and Raman scattering, it was confirmed that the silicon carbide single crystal was a high-quality silicon carbide single crystal consisting of a single polytype of 4H and having few defects. When this silicon carbide single crystal ingot was ground, cut, and polished to produce a silicon carbide single crystal substrate, a high-quality silicon carbide single crystal substrate consisting of a single polytype of 4H was produced. When producing an electronic device on a silicon carbide single crystal substrate, defects existing in the substrate affect the characteristics of the electronic device. Therefore, the high-quality silicon carbide single crystal substrate obtained by the present invention has few defects. It is useful as a substrate for manufacturing a device.

(実施例3)
図5にあるように、蓋部、成長空間側壁部、原料側壁部、及び底部の4つの黒鉛坩堝部材からなる坩堝を組立てて作製した。坩堝の外形は150mm、原料が装填される部分の内径は130mmとした。底部と原料側壁部とをつなぐ接続部3は、底部に形成された雄ねじと原料側壁部に形成された雌ねじとを螺合させた長さ20mmのねじ部で形成した。上記雄ねじと雌ねじはJIS規格に則り、径が140mm、ピッチが1mmとした。原料側壁部と成長空間側壁部とをつなぐ接続部2は原料から20mm離れた部分に配置した。接続部2は長さ40mmのねじ部で形成した。雄ねじと雌ねじはJIS規格に則り、径が140mm、ピッチが2mmとした。成長空間側壁部と蓋部とをつなぐ接続部1は原料から20mm以上離れた位置に配置した。接続部1は長さ10mmのねじ部で形成した。雄ねじと雌ねじはJIS規格に則り、径が140mm、ピッチが1mmとした。
(Example 3)
As shown in FIG. 5, a crucible composed of four graphite crucible members including a lid, a growth space side wall, a raw material side wall, and a bottom was assembled. The outer diameter of the crucible was 150 mm, and the inner diameter of the portion charged with the raw material was 130 mm. The connecting portion 3 connecting the bottom and the raw material side wall was formed by a screw portion having a length of 20 mm in which a male screw formed on the bottom and a female screw formed on the raw material side wall were screwed together. The male screw and female screw were compliant with JIS standards and had a diameter of 140 mm and a pitch of 1 mm. The connecting portion 2 connecting the raw material side wall and the growth space side wall was disposed at a portion 20 mm away from the raw material. The connection part 2 was formed by a screw part having a length of 40 mm. The male screw and female screw were compliant with JIS standards, with a diameter of 140 mm and a pitch of 2 mm. The connecting portion 1 connecting the growth space side wall portion and the lid portion was disposed at a position separated from the raw material by 20 mm or more. The connecting part 1 was formed by a screw part having a length of 10 mm. The male screw and female screw were compliant with JIS standards, with a diameter of 140 mm and a pitch of 1 mm.

まず、種結晶として口径102mmの(0001)面を有した4Hポリタイプの炭化珪素単結晶ウェハを用意し、蓋部に取り付けた。次に、種結晶を取り付けた蓋部と成長空間側壁部とを互いにねじで組み合わせて固定した。原料側壁部と底部とを互いにねじで組み合わせ、その内部にアチソン法により作製された炭化珪素結晶原料粉末を装填した。最後に、原料側壁部と成長空間側壁部とを互いにねじで組み合わせて固定することで、炭化珪素単結晶成長用坩堝をくみ上げた。この坩堝を、上に述べたように、支持台の上に載せ、60時間結晶成長を行った。   First, a 4H polytype silicon carbide single crystal wafer having a (0001) face with a diameter of 102 mm was prepared as a seed crystal, and attached to the lid. Next, the lid portion to which the seed crystal was attached and the growth space side wall portion were fixed together by screws. The raw material side wall portion and the bottom portion were combined with each other by screws, and the silicon carbide crystal raw material powder produced by the Atchison method was loaded therein. Finally, the silicon carbide single crystal growth crucible was lifted by fixing the raw material side wall portion and the growth space side wall portion with screws. As described above, this crucible was placed on a support base and crystal growth was performed for 60 hours.

得られた結晶の口径は105mm程度で高さは40mm程度であった。成長速度は約0.7mm/時であった。こうして得られた炭化珪素単結晶をX線回折及びラマン散乱を用いて分析したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶であることが確認された。この炭化珪素単結晶インゴットを研削、切断、研磨して炭化珪素単結晶基板を作製したところ、4Hの単一ポリタイプからなる欠陥の少ない高品質の炭化珪素単結晶の基板が作製できた。炭化珪素単結晶基板上に電子デバイスを作製する場合、基板に存在する欠陥が電子デバイスの特性に影響を与えるため、本発明により得られた欠陥の少ない高品質の炭化珪素単結晶基板は、電子デバイスを作製するための基板として有用である。   The diameter of the obtained crystal was about 105 mm and the height was about 40 mm. The growth rate was about 0.7 mm / hour. When the silicon carbide single crystal thus obtained was analyzed using X-ray diffraction and Raman scattering, it was confirmed that the silicon carbide single crystal was a high-quality silicon carbide single crystal consisting of a single polytype of 4H and having few defects. When this silicon carbide single crystal ingot was ground, cut, and polished to produce a silicon carbide single crystal substrate, a high-quality silicon carbide single crystal substrate consisting of a single polytype of 4H was produced. When producing an electronic device on a silicon carbide single crystal substrate, defects existing in the substrate affect the characteristics of the electronic device. Therefore, the high-quality silicon carbide single crystal substrate obtained by the present invention has few defects. It is useful as a substrate for manufacturing a device.

(比較例)
次に、比較例について説明する。実施例2と同様に、図5にあるように、蓋部、成長空間側壁部、原料側壁部、及び底部の4つの黒鉛坩堝部材を組立てて坩堝を作製した。坩堝の外形は130mm、原料を充填する部分の内径は110mmとした。底部と原料側壁部とをつなぐ接続部3は、長さ4mmのねじ部で形成した。雄ねじ及び雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。原料側壁部と成長空間側壁部とをつなぐ接続部2は原料から15mm離れた部分に配置した。接続部2は長さ4mmのねじ部で形成した。雄ねじ及び雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。成長空間側壁部と蓋部とをつなぐ接続部1は原料から20mm以上離れた位置に配置した。接続部1は長さ4mmのねじ部で形成した。雄ねじ及び雌ねじはJIS規格に則り、径が115mm、ピッチが1mmとした。
(Comparative example)
Next, a comparative example will be described. As in Example 2, as shown in FIG. 5, four graphite crucible members of a lid, a growth space side wall, a raw material side wall, and a bottom were assembled to produce a crucible. The outer diameter of the crucible was 130 mm, and the inner diameter of the portion filled with the raw material was 110 mm. The connection part 3 connecting the bottom part and the raw material side wall part was formed by a thread part having a length of 4 mm. The male screw and female screw had a diameter of 115 mm and a pitch of 1 mm in accordance with JIS standards. The connecting portion 2 connecting the raw material side wall and the growth space side wall was disposed at a portion 15 mm away from the raw material. The connection part 2 was formed by a thread part having a length of 4 mm. The male screw and female screw had a diameter of 115 mm and a pitch of 1 mm in accordance with JIS standards. The connecting portion 1 connecting the growth space side wall portion and the lid portion was disposed at a position separated from the raw material by 20 mm or more. The connection part 1 was formed by a thread part having a length of 4 mm. The male screw and female screw had a diameter of 115 mm and a pitch of 1 mm in accordance with JIS standards.

まず、種結晶として口径76mmの(0001)面を有した4Hポリタイプの炭化珪素単結晶ウェハを用意し、蓋部に取り付けた。次に、種結晶を取り付けた蓋部と成長空間側壁部とを互いにねじで組み合わせて固定した。原料側壁部と底部とを互いにねじで組み合わせ、その内部にCVD法により作製された高純度炭化珪素結晶原料粉末を装填した。最後に、原料側壁部と成長空間側壁部とを互いにねじで組み合わせて固定することで、炭化珪素単結晶成長用坩堝をくみ上げた。この坩堝を、上に述べたように、支持台の上に載せ、60時間結晶成長を行った。   First, a 4H polytype silicon carbide single crystal wafer having a (0001) plane with a diameter of 76 mm was prepared as a seed crystal, and attached to the lid. Next, the lid portion to which the seed crystal was attached and the growth space side wall portion were fixed together by screws. The raw material side wall portion and the bottom portion were combined with each other with screws, and high purity silicon carbide crystal raw material powder produced by a CVD method was loaded therein. Finally, the silicon carbide single crystal growth crucible was lifted by fixing the raw material side wall portion and the growth space side wall portion with screws. As described above, this crucible was placed on a support base and crystal growth was performed for 60 hours.

得られた結晶の口径は80mm程度で高さは15mm程度であった。成長速度は約0.25mm/時であった。原料側壁部の周囲に配置した断熱材には炭化珪素が再結晶しており、断熱性の劣化が観察された。また、得られた炭化珪素結晶をX線回折及びラマン散乱を用いて分析したところ、4Hや6H等のポリタイプが混在しており、結晶性の劣化が観察された。この炭化珪素単結晶インゴットを研削、切断、研磨して炭化珪素単結晶基板を作製しても結晶性が悪いために、電子材料用の基板としては役に立たない。   The diameter of the obtained crystal was about 80 mm and the height was about 15 mm. The growth rate was about 0.25 mm / hour. Silicon carbide was recrystallized in the heat insulating material arranged around the raw material side wall, and deterioration of the heat insulating property was observed. Moreover, when the obtained silicon carbide crystal was analyzed using X-ray diffraction and Raman scattering, polytypes such as 4H and 6H were mixed, and deterioration of crystallinity was observed. Even if this silicon carbide single crystal ingot is ground, cut, and polished to produce a silicon carbide single crystal substrate, the crystallinity is poor, so that it is not useful as a substrate for electronic materials.

改良レーリー法の原理を説明する図Diagram explaining the principle of the improved Rayleigh method 本発明の単結晶成長用坩堝を説明する図The figure explaining the crucible for single crystal growth of this invention 本実施例の単結晶成長装置を説明する図The figure explaining the single-crystal growth apparatus of a present Example 本実施例の単結晶成長用坩堝を説明する図The figure explaining the crucible for single crystal growth of a present Example 本実施例の単結晶成長用坩堝を説明する図The figure explaining the crucible for single crystal growth of a present Example

符号の説明Explanation of symbols

1 種結晶(炭化珪素単結晶)
2 炭化珪素結晶粉末原料
3 黒鉛製坩堝
4 黒鉛製坩堝蓋
5 二重石英管
6 支持棒
7 黒鉛製フェルト(断熱材)
8 ワークコイル
9 高純度Arガス配管
10 高純度Arガス用マスフローコントローラ
11 真空排気装置
1 seed crystal (silicon carbide single crystal)
2 Silicon carbide crystal powder raw material
3 Graphite crucible
4 Graphite crucible lid
5 Double quartz tube
6 Support rod
7 Graphite felt (insulation)
8 Work coil
9 High purity Ar gas piping
10 Mass flow controller for high purity Ar gas
11 Vacuum exhaust system

Claims (4)

2以上の黒鉛坩堝部材を組立ててなる炭化珪素単結晶成長用蓋付き黒鉛坩堝であって、黒鉛坩堝の内径が75mm以上であり、少なくとも該黒鉛坩堝内に充填される炭化珪素原料から20mm以内に位置する2つの黒鉛坩堝部材の接続部は、一方の黒鉛坩堝部材に形成された雄ねじと、他方の黒鉛坩堝部材に形成された雌ねじとを螺合させた長さ5mm以上40mm以下のねじ部からなることを特徴とする蓋付き黒鉛坩堝。   A graphite crucible with a silicon carbide single crystal growth lid formed by assembling two or more graphite crucible members, wherein the graphite crucible has an inner diameter of 75 mm or more, and at least within 20 mm from the silicon carbide raw material filled in the graphite crucible The connecting portion between the two graphite crucible members positioned from a screw portion having a length of 5 mm or more and 40 mm or less in which a male screw formed on one graphite crucible member and a female screw formed on the other graphite crucible member are screwed together. A graphite crucible with a lid. 黒鉛坩堝部材同士の全ての接続部は、一方の黒鉛坩堝部材に形成された雄ねじと、他方の黒鉛坩堝部材に形成された雌ねじとを螺合させたねじ部からなる請求項1記載の蓋付き黒鉛坩堝。   2. The lid according to claim 1, wherein all the connecting portions between the graphite crucible members are formed by screwing a male screw formed on one graphite crucible member and a female screw formed on the other graphite crucible member. Graphite crucible. 前記該黒鉛坩堝内に充填される炭化珪素原料から20mm以内に位置する接続部以外の少なくとも1箇所の接続部のねじ部の長さが、炭化珪素原料から20mm以内に位置する接続部のねじ部の長さよりも短い請求項2記載の蓋付き黒鉛坩堝。   The length of the threaded portion of the connecting portion other than the connecting portion located within 20 mm from the silicon carbide raw material filled in the graphite crucible is the threaded portion of the connecting portion located within 20 mm from the silicon carbide raw material. 3. The graphite crucible with a lid according to claim 2, wherein the graphite crucible is shorter than the length of the graphite crucible. 請求項1〜3のいずれかに記載の蓋付き黒鉛坩堝を少なくとも用いてなる炭化珪素単結晶成長装置。   A silicon carbide single crystal growth apparatus using at least the graphite crucible with a lid according to any one of claims 1 to 3.
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