JP6910168B2

JP6910168B2 - Silicon Carbide Single Crystal Ingot Manufacturing Equipment and Manufacturing Method

Info

Publication number: JP6910168B2
Application number: JP2017055636A
Authority: JP
Inventors: 弘志柘植; 藤本　辰雄; 辰雄藤本; 勝野　正和; 正和勝野; 正史中林; 佐藤　信也; 信也佐藤; 昌史牛尾
Original assignee: Showa Denko KK
Current assignee: Resonac Holdings Corp
Priority date: 2017-03-22
Filing date: 2017-03-22
Publication date: 2021-07-28
Anticipated expiration: 2037-03-22
Also published as: JP2018158857A

Description

本発明は、種結晶を用いた昇華再結晶法によって炭化珪素単結晶を成長させ、炭化珪素単結晶インゴットを製造するための製造装置及び製造方法に関する。 The present invention relates to a manufacturing apparatus and a manufacturing method for growing a silicon carbide single crystal by a sublimation recrystallization method using a seed crystal to manufacture a silicon carbide single crystal ingot.

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。
そして、このような炭化珪素単結晶の作製法の一つとして、昇華再結晶法(レーリー法)が知られている。この昇華再結晶法は、２０００℃を超える高温において原料の炭化珪素粉末を昇華させ、生成したその昇華ガス（原料ガス）を低温部に再結晶化させることにより、炭化珪素単結晶を製造する方法である。また、このレーリー法において、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インゴットの製造に利用されている。 A silicon carbide single crystal having a high thermal conductivity and a large bandgap is a useful material as a substrate for an electronic material used at a high temperature or an electronic material required to have a high withstand voltage.
The sublimation recrystallization method (Rayleigh method) is known as one of the methods for producing such a silicon carbide single crystal. This sublimation recrystallization method is a method for producing a silicon carbide single crystal by sublimating the raw material silicon carbide powder at a high temperature exceeding 2000 ° C. and recrystallizing the generated sublimation gas (raw material gas) in a low temperature portion. Is. Further, in this Rayleigh method, a method for producing a silicon carbide single crystal using a seed crystal composed of a silicon carbide single crystal is particularly called an improved Rayleigh method (Non-Patent Document 1), and is a bulk silicon carbide single crystal ingot. It is used in the manufacture of.

この改良レーリー法においては、種結晶を用いているために結晶の核形成過程を最適化することができ、また、不活性ガスによる雰囲気圧力を１０Paから１５kPa程度にすることにより、炭化珪素単結晶インゴットの製造の際に成長速度等の結晶成長条件の再現性を良くすることができる。このため、一般に、原料と種結晶との間で適切な温度差を設け、種結晶の上に炭化珪素単結晶を成長させることが行われている。また、得られた炭化珪素単結晶（炭化珪素単結晶インゴット）については、電子材料の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て利用されている。 In this improved Rayleigh method, since the seed crystal is used, the nucleation process of the crystal can be optimized, and the atmospheric pressure due to the inert gas is set to about 10 Pa to 15 kPa to make the silicon carbide single crystal. It is possible to improve the reproducibility of crystal growth conditions such as growth rate during the production of ingots. For this reason, in general, a silicon carbide single crystal is grown on the seed crystal by providing an appropriate temperature difference between the raw material and the seed crystal. Further, the obtained silicon carbide single crystal (silicon carbide single crystal ingot) is used after being subjected to processing such as grinding, cutting, and polishing in order to obtain a standard shape as a substrate for an electronic material.

ここで、図４を用いて、改良レーリー法の原理を説明する。
改良レーリー法に係る昇華再結晶法においては、炭化珪素原料３として炭化珪素結晶粉末〔通常、アチソン(Acheson)法で作製された炭化珪素結晶粉末を洗浄・前処理したものが使用される。〕が用いられ、また、上端に開口部を有して円筒状に形成された坩堝本体1aとこの坩堝本体1aの開口部を閉塞する坩堝上蓋1bとを備えた黒鉛製坩堝（以下、単に「坩堝」ともいう。）１が用いられ、この坩堝１にはその下部の原料装填部1cとその上部の結晶成長部1dとが構成される。前記坩堝１は、図示外の二重石英管内に設置され前記原料装填部1c内に炭化珪素原料３が装填され、また、前記結晶成長部1dの坩堝上蓋1bの内面に炭化珪素単結晶からなる種結晶２が設置される。そして、坩堝１内では、前記炭化珪素原料３が、アルゴン等の不活性ガス雰囲気中（10Pa〜15kPa）で２４００℃以上に加熱され、この加熱の際に、坩堝１内は原料装填部1c内の炭化珪素原料３側に比べて結晶成長部1d内の種結晶２側がやや低温になるように温度勾配が設定され、加熱されて炭化珪素原料３から昇華した炭化珪素の昇華ガスは、濃度勾配（温度勾配により形成される）により種結晶２方向へと拡散し、輸送され、そしてこの種結晶２の表面で再結晶し、結晶成長が進行して単結晶インゴット４が生成する。なお、図４中、符号５は断熱部材である。 Here, the principle of the improved Rayleigh method will be described with reference to FIG.
In the sublimation recrystallization method according to the improved Rayleigh method, silicon carbide crystal powder [usually, a silicon carbide crystal powder produced by the Acheson method is washed and pretreated is used as the silicon carbide raw material 3. ] Is used, and a graphite crucible with a crucible body 1a formed in a cylindrical shape with an opening at the upper end and a crucible top lid 1b that closes the opening of the crucible body 1a (hereinafter, simply " (Also referred to as "crucible") 1 is used, and the crucible 1 is composed of a raw material loading portion 1c below the crucible and a crystal growth portion 1d above the crucible. The crucible 1 is installed in a double quartz tube (not shown), the silicon carbide raw material 3 is loaded in the raw material loading portion 1c, and the inner surface of the crucible upper lid 1b of the crystal growth portion 1d is made of a silicon carbide single crystal. Seed crystal 2 is installed. Then, in the crucible 1, the silicon carbide raw material 3 is heated to 2400 ° C. or higher in an atmosphere of an inert gas such as argon (10 Pa to 15 kPa), and at the time of this heating, the inside of the crucible 1 is inside the raw material loading unit 1c. The temperature gradient is set so that the seed crystal 2 side in the crystal growth portion 1d is slightly lower than the silicon carbide raw material 3 side of the above, and the sublimation gas of silicon carbide that is heated and sublimated from the silicon carbide raw material 3 has a concentration gradient. (Formed by a temperature gradient) diffuses in two directions of the seed crystal, is transported, and recrystallizes on the surface of the seed crystal 2, and crystal growth proceeds to produce a single crystal ingot 4. In FIG. 4, reference numeral 5 is a heat insulating member.

ところで、炭化珪素単結晶基板の口径については、電子デバイスを作製するための基板として用いる際の製造コストをできるだけ下げるために、大口径化が求められている。そして、このために、炭化珪素単結晶基板を製造するためのインゴットについては、その大口径化と同時に、一つのインゴットから多数の基板を製造することができ、また、切断加工時や研削加工時の生産性をより高めることができるように、結晶成長により得られるインゴットの長尺化も求められている。 By the way, the diameter of the silicon carbide single crystal substrate is required to be increased in order to reduce the manufacturing cost as much as possible when it is used as a substrate for manufacturing an electronic device. For this reason, as for the ingot for manufacturing the silicon carbide single crystal substrate, at the same time as increasing the diameter, a large number of substrates can be manufactured from one ingot, and at the time of cutting or grinding. There is also a need to lengthen the ingot obtained by crystal growth so that the productivity of the ingot can be further increased.

しかるに、改良レーリー法においては、前記のような方法で結晶成長を行っているため、炭化珪素原料を結晶成長の途中で追加することが困難であり、大口径かつ長尺の炭化珪素単結晶インゴットを作製するためには、小口径のインゴットを結晶成長させる場合に比べて、不可避的に坩堝の原料装填部をより大きくし、この原料装填部内により多量の炭化珪素原料を装填する必要がある。 However, in the improved Rayleigh method, since the crystal growth is carried out by the method as described above, it is difficult to add the silicon carbide raw material in the middle of the crystal growth, and a large-diameter and long silicon carbide single crystal ingot. In order to produce the crucible, it is inevitably necessary to make the raw material loading portion of the crucible larger and load a larger amount of silicon carbide raw material into the raw material loading portion as compared with the case where a small-diameter ingot is crystal-grown.

しかしながら、炭化珪素原料から生じた昇華ガスは、炭素と珪素の比が1対1では無く、炭素に比べて珪素の割合が多く、また、再結晶した後には組成比が1対1になることから、結晶成長に寄与しない余剰の珪素が発生し、この余剰の珪素が坩堝外部に漏出することが多々発生する。そして、この坩堝外部に漏出した余剰の珪素は、断熱部材で冷却されて析出し、若しくは、断熱部材と反応して反応生成物を形成し、断熱部材に劣化を引き起こしてその断熱性能を低下させる。 However, the sublimation gas generated from the silicon carbide raw material has a carbon-silicon ratio of not 1: 1 but a higher ratio of silicon than carbon, and the composition ratio becomes 1: 1 after recrystallization. Therefore, surplus silicon that does not contribute to crystal growth is generated, and this surplus silicon often leaks to the outside of the pit. Then, the excess silicon leaked to the outside of the crucible is cooled by the heat insulating member and precipitated, or reacts with the heat insulating member to form a reaction product, which causes deterioration of the heat insulating member and deteriorates its heat insulating performance. ..

そして、炭化珪素単結晶インゴットを製造する過程において、昇華ガスの漏出を完全に抑制することは困難である。この昇華ガスの漏出の多寡や漏出の状態は、断熱部材を形成する黒鉛材料の特性に起因する発熱分布、及び温度分布のバッチ毎の揺らぎ等に依存しており、バッチ毎の再現性が低くて制御することが困難であるからである。そのため、昇華ガスの漏出に伴う断熱部材の劣化に起因したバッチ間の変動を予想し、これを結晶成長条件にフィードバックすることが難しく、断熱部材の劣化のばらつきが昇華再結晶法による結晶成長状態のバッチ間のばらつきの原因になっており、また、結晶成長条件の最適化や再現性の確保を困難にし、結晶成長の歩留りを低下させる原因になっている。 Then, in the process of producing the silicon carbide single crystal ingot, it is difficult to completely suppress the leakage of the sublimation gas. The amount of leakage of the sublimation gas and the state of leakage depend on the heat generation distribution due to the characteristics of the graphite material forming the heat insulating member and the fluctuation of the temperature distribution for each batch, and the reproducibility for each batch is low. This is because it is difficult to control. Therefore, it is difficult to predict fluctuations between batches due to deterioration of the heat insulating member due to leakage of sublimation gas and feed this back to the crystal growth conditions, and the variation in deterioration of the heat insulating member is the crystal growth state by the sublimation recrystallization method. It causes variation between batches, makes it difficult to optimize crystal growth conditions and ensure reproducibility, and causes a decrease in crystal growth yield.

また、前述のように、昇華再結晶法では、炭化珪素原料が装填される原料装填部を高温にし、結晶を成長させる結晶成長部を相対的に低温に制御する必要があり、この温度差は成長速度等の結晶成長の良否を決める重要な因子である。原料装填部を結晶成長部よりも高温に維持する必要があるため、原料装填部の周囲の断熱部材は結晶成長部の周囲の断熱部材よりも高温に晒される。そして、断熱部材と漏出ガスとの反応は、温度が高ければ高いほど速く進行し断熱性能の劣化が促進され易くなる。その結果、坩堝の側方に位置する断熱部材は、原料装填部の側方に位置する部分が結晶成長部の側方に位置する部分に比べて断熱性能の劣化がより進み易くなり原料装填部の断熱が悪くなる。その結果、原料装填部の温度を結晶成長部よりも高温に制御された状態に維持して炭化珪素原料を適切に加熱することが困難になり、結晶成長の重要な因子である原料装填部内の炭化珪素原料側と結晶成長部内の種結晶側との間の温度差（温度勾配）を適切な値に制御することが難しいという問題がある。 Further, as described above, in the sublimation recrystallization method, it is necessary to raise the temperature of the raw material loading portion in which the silicon carbide raw material is loaded and control the crystal growth portion in which the crystal grows to a relatively low temperature. It is an important factor that determines the quality of crystal growth such as growth rate. Since the raw material loading portion needs to be maintained at a higher temperature than the crystal growth portion, the heat insulating member around the raw material loading portion is exposed to a higher temperature than the heat insulating member around the crystal growth portion. The reaction between the heat insulating member and the leaked gas proceeds faster as the temperature rises, and the deterioration of the heat insulating performance is likely to be promoted. As a result, in the heat insulating member located on the side of the crucible, the deterioration of the heat insulating performance is more likely to proceed than the portion where the portion located on the side of the raw material loading portion is located on the side of the crystal growth portion, and the raw material loading portion Insulation deteriorates. As a result, it becomes difficult to properly heat the silicon carbide raw material while maintaining the temperature of the raw material loading part at a higher temperature than the crystal growth part, and the inside of the raw material loading part, which is an important factor of crystal growth, becomes difficult. There is a problem that it is difficult to control the temperature difference (temperature gradient) between the silicon carbide raw material side and the seed crystal side in the crystal growth portion to an appropriate value.

従来においても、このような漏出ガスに起因した断熱部材の劣化に伴う断熱性能の低下の問題を解消するために、幾つかの提案がされている。
例えば、特許文献１においては、坩堝と断熱部材の間に空隙を設け、坩堝から漏出した漏出ガスが断熱部材で析出し、若しくは、反応生成物を形成しないようにする工夫が提案されている。この方法によると空隙を通して漏出ガスが系外に排出されるため、断熱部材の劣化が抑制される。
また、特許文献２においては、坩堝に対して断熱部材を移動させる方法が提案されている。この方法は、坩堝に対して断熱部材を移動させることにより、成長過程の結晶部分における温度分布を調整し、最適化を行っている。 Conventionally, some proposals have been made in order to solve the problem of deterioration of heat insulating performance due to deterioration of heat insulating member due to such leaked gas.
For example, Patent Document 1 proposes a device in which a gap is provided between the crucible and the heat insulating member so that the leaked gas leaked from the crucible does not precipitate at the heat insulating member or form a reaction product. According to this method, the leaked gas is discharged to the outside of the system through the voids, so that the deterioration of the heat insulating member is suppressed.
Further, Patent Document 2 proposes a method of moving the heat insulating member with respect to the crucible. In this method, the temperature distribution in the crystal part of the growth process is adjusted and optimized by moving the heat insulating member with respect to the crucible.

特開2011-219,295号公報Japanese Unexamined Patent Publication No. 2011-219,295 特開2011-219,287号公報Japanese Unexamined Patent Publication No. 2011-219,287

Yu. M. Tairov and V. F. Tsvetkov, Journal of Crystal Growth, 52 (1981) pp.146Yu. M. Tairov and V. F. Tsvetkov, Journal of Crystal Growth, 52 (1981) pp.146

しかしながら、特許文献１の方法では、坩堝から漏出したガスは依然として存在しており、その漏出ガスが断熱部材に付着して析出すること、若しくは、断熱部材の黒鉛材と反応生成物を形成することを完全には防止することができず、抑制はされても断熱部材の劣化が生じ、断熱部材の性能の低下が観察される。前記のように、特に高温になる原料装填部近傍に配置された断熱部材の劣化は、結晶成長部近傍に配置された断熱部材の劣化に比べて大きく、原料装填部内の原料と結晶成長部内で成長過程の結晶との間の温度差（温度勾配）を再現性良く制御することは難しい。 However, in the method of Patent Document 1, the gas leaked from the flatulence still exists, and the leaked gas adheres to and precipitates on the heat insulating member, or forms a reaction product with the graphite material of the heat insulating member. Can not be completely prevented, and even if it is suppressed, deterioration of the heat insulating member occurs, and deterioration of the performance of the heat insulating member is observed. As described above, the deterioration of the heat insulating member arranged in the vicinity of the raw material loading portion, which becomes particularly high, is larger than the deterioration of the heat insulating member arranged in the vicinity of the crystal growth portion, and in the raw material in the raw material loading portion and in the crystal growth portion. It is difficult to control the temperature difference (temperature gradient) between crystals in the growth process with good reproducibility.

また、特許文献２の方法では、成長している結晶部分の温度分布を変えることを目的としているため、原料装填部近傍での断熱部材の劣化を抑制することは難しい。また、断熱部材の移動方向が坩堝に対して上から下の方向に向かっており、上部である結晶成長部に新鮮な断熱部材が供給されることになってこの結晶成長部を高温にし、原料と結晶との間の温度差を低減させ易い。結晶成長中に原料と結晶との間の温度差（温度勾配）が小さくなると成長の駆動力が小さくなり、結晶成長が逆に抑制され易くなるという問題がある。 Further, since the method of Patent Document 2 aims to change the temperature distribution of the growing crystal portion, it is difficult to suppress the deterioration of the heat insulating member in the vicinity of the raw material loading portion. In addition, the moving direction of the heat insulating member is from the top to the bottom with respect to the crucible, and a fresh heat insulating member is supplied to the upper crystal growth part, so that the crystal growth part is heated to a high temperature and the raw material is used. It is easy to reduce the temperature difference between the crystal and the crystal. If the temperature difference (temperature gradient) between the raw material and the crystal becomes small during crystal growth, the driving force for growth becomes small, and there is a problem that crystal growth is conversely easily suppressed.

そこで、本発明者らは、高周波誘導加熱を用いて大口径かつ長尺の炭化珪素単結晶インゴットを製造する場合に、坩堝の原料装填部内に装填した炭化珪素原料を再現性良く、かつ、効率良く昇華させることが可能な手段について鋭意検討した。その結果、結晶成長中に坩堝の外周側面に配置した断熱部材を坩堝に対して、下から上に移動させることにより、劣化が進み易い原料装填部周辺の断熱部材を経時的に新しい断熱部材と置き換えることにより、この原料装填部周辺での断熱部材の劣化を可及的に低減し、結晶成長中に原料装填部内の内壁面近傍の炭化珪素原料が断熱部材の断熱性能低下の影響を受け難くすることが可能であることを見出した。また、この結果、結晶成長中に原料と結晶との間の温度差を安定的に制御することができ、同時に、坩堝内における発熱分布のバッチ間変動を小さくすることができ、再現性良く制御して原料装填部内に装填された炭化珪素原料を昇華させることが可能になり、大口径かつ長尺の炭化珪素単結晶インゴットを再現性良く、かつ、効率良く製造することができることを見出した。 Therefore, the present inventors have good reproducibility and efficiency of the silicon carbide raw material loaded in the raw material loading portion of the crucible when producing a large-diameter and long silicon carbide single crystal ingot using high-frequency induction heating. We diligently examined the means that can be sublimated well. As a result, by moving the heat insulating member arranged on the outer peripheral side surface of the crucible from the bottom to the top with respect to the crucible during crystal growth, the heat insulating member around the raw material loading portion, which tends to deteriorate, becomes a new heat insulating member over time. By replacing it, the deterioration of the heat insulating member around the raw material loading portion is reduced as much as possible, and the silicon carbide raw material near the inner wall surface in the raw material loading portion is less likely to be affected by the deterioration of the heat insulating performance of the heat insulating member during crystal growth. Found that it is possible to do. Further, as a result, the temperature difference between the raw material and the crystal can be stably controlled during crystal growth, and at the same time, the variation of the heat generation distribution in the crucible between batches can be reduced, and the control can be performed with good reproducibility. It has been found that the silicon carbide raw material loaded in the raw material loading unit can be sublimated, and a large-diameter and long silicon carbide single crystal ingot can be produced with good reproducibility and efficiency.

本発明は、かかる知見に基づいて創案されたものであり、炭化珪素単結晶の成長中に坩堝の外周側面に配置した断熱部材が、坩堝からの漏出ガスにより劣化することの影響を可及的に低減し、結晶成長の全過程に亘って原料と結晶との間の温度差（温度勾配）を適切に維持することができる炭化珪素単結晶インゴットの製造装置を提供することを目的とするものである。
また、本発明は、坩堝の原料装填部に装填した炭化珪素原料を再現性良く、また、効率良く昇華させることができ、大口径かつ長尺の炭化珪素単結晶インゴットを製造するのに適した炭化珪素単結晶インゴットの製造方法を提供することを目的とするものである。 The present invention was devised based on such findings, and it is possible that the heat insulating member arranged on the outer peripheral side surface of the crucible deteriorates due to the leakage gas from the crucible during the growth of the silicon carbide single crystal. It is an object of the present invention to provide a silicon carbide single crystal ingot manufacturing apparatus capable of appropriately maintaining a temperature difference (temperature gradient) between a raw material and a crystal over the entire process of crystal growth. Is.
Further, the present invention can sublimate the silicon carbide raw material loaded in the raw material loading portion of the crucible with good reproducibility and efficiently, and is suitable for producing a large-diameter and long-length silicon carbide single crystal ingot. It is an object of the present invention to provide a method for producing a silicon carbide single crystal ingot.

すなわち、本発明の要旨は次の通りである。
(1) 炭化珪素原料が装填される原料装填部、及び炭化珪素単結晶インゴットが成長する結晶成長部を有する坩堝と、この坩堝の外周側面を取り囲むように配置される側面断熱部材とを備え、前記原料装填部内の炭化珪素原料を加熱して発生した昇華ガスを、前記結晶成長部の種結晶上に再結晶させる昇華再結晶法により、炭化珪素単結晶インゴットを製造する炭化珪素単結晶インゴットの製造装置において、
前記坩堝と側面断熱部材とを坩堝高さ方向に相対的に移動させる移動機構が設けられていると共に、前記側面断熱部材には、坩堝側方に位置して原料装填部及び結晶成長部を断熱する基断熱領域に加えて、坩堝高さ方向に少なくとも坩堝の原料装填部の高さ（L1）に相当する長さの延長断熱領域が設けられており、
炭化珪素単結晶インゴットの製造過程において、前記移動機構により坩堝と側面断熱部材とを相対的に移動させ、前記側面断熱部材の基断熱領域のうち、少なくとも原料装填部の側方に位置してこの原料装填部を断熱する原料対応断熱領域を延長断熱領域に更新可能にしたことを特徴とする炭化珪素単結晶インゴットの製造装置。
(2) 前記側面断熱部材には、坩堝の側方に位置する基断熱領域に加えて、坩堝の原料装填部及び結晶成長部の高さ（L2）に相当する長さの延長断熱領域が設けられており、炭化珪素単結晶インゴットの製造過程で、前記坩堝と側面断熱部材とを坩堝高さ方向に相対的に移動させ、前記基断熱領域の全てを前記延長断熱領域に更新可能にしたことを特徴とする前記(1)に記載の炭化珪素単結晶インゴットの製造装置。
(3) 前記側面断熱部材の延長断熱領域は、前記側面断熱部材の基断熱領域の下方側に位置し、坩堝に対して側面断熱部材を相対的に上昇させることにより、前記基断熱領域のうちの少なくとも前記原料対応断熱領域を延長断熱領域に更新する前記(1)又は(2)に記載の炭化珪素単結晶インゴットの製造装置。 That is, the gist of the present invention is as follows.
(1) It is provided with a raw material loading portion in which a silicon carbide raw material is loaded, a pit having a crystal growth portion in which a silicon carbide single crystal ingot grows, and a side heat insulating member arranged so as to surround the outer peripheral side surface of the pit. A silicon carbide single crystal ingot for producing a silicon carbide single crystal ingot by a sublimation recrystallization method in which the sublimation gas generated by heating the silicon carbide raw material in the raw material loading section is recrystallized on the seed crystal of the crystal growth section. In manufacturing equipment
A moving mechanism for relatively moving the crucible and the side surface heat insulating member in the crucible height direction is provided, and the side surface heat insulating member is located on the side of the crucible to insulate the raw material loading portion and the crystal growth portion. In addition to the basic heat insulating region, an extended heat insulating region having a length corresponding to at least the height (L1) of the raw material loading portion of the crucible is provided in the crucible height direction.
In the manufacturing process of the silicon carbide single crystal ingot, the crucible and the side heat insulating member are relatively moved by the moving mechanism, and the crucible and the side heat insulating member are located at least on the side of the raw material loading portion in the basic heat insulating region of the side heat insulating member. A silicon carbide single crystal ingot manufacturing apparatus characterized in that the raw material-compatible heat insulating region that insulates the raw material loading portion can be updated to an extended heat insulating region.
(2) In addition to the basic heat insulating region located on the side of the crucible, the side heat insulating member is provided with an extended heat insulating region having a length corresponding to the height (L2) of the raw material loading portion and the crystal growth portion of the crucible. In the process of manufacturing the silicon carbide single crystal ingot, the crucible and the side heat insulating member were relatively moved in the crucible height direction so that all of the basic heat insulating region could be updated to the extended heat insulating region. The silicon carbide single crystal ingot manufacturing apparatus according to (1) above.
(3) The extended heat insulating region of the side heat insulating member is located below the basic heat insulating region of the side heat insulating member, and is included in the basic heat insulating region by raising the side heat insulating member relative to the crucible. The silicon carbide single crystal ingot manufacturing apparatus according to (1) or (2) above, wherein at least the heat insulating region corresponding to the raw material is updated to an extended heat insulating region.

(4) 炭化珪素原料が装填される原料装填部、及び炭化珪素単結晶インゴットが成長する結晶成長部を有する坩堝と、この坩堝の外周側面を取り囲むように配置された側面断熱部材とを備えた製造装置を用いて、前記原料装填部内の炭化珪素原料を加熱して発生した昇華ガスを、前記結晶成長部の種結晶上に再結晶させる昇華再結晶法により、炭化珪素単結晶インゴットを製造するに際し、
前記坩堝と側面断熱部材とを坩堝高さ方向に相対的に移動させる移動機構を備えていると共に、前記側面断熱部材には、坩堝側方に位置して原料装填部及び結晶成長部を断熱する基断熱領域に加えて、坩堝高さ方向に少なくとも坩堝の原料装填部の長さ（L1）に相当する長さの延長断熱領域が設けられた製造装置を用い、
前記坩堝と側面断熱部材とを相対的に移動させ、前記側面断熱部材の基断熱領域のうち、少なくとも原料装填部の側方に位置してこの原料装填部を断熱する原料対応断熱領域を延長断熱領域に更新しながら炭化珪素単結晶インゴットを製造することを特徴とする炭化珪素単結晶インゴットの製造方法。
(5) 前記側面断熱部材は、坩堝側方に位置する基断熱領域に加えて、坩堝高さ方向に坩堝の原料装填部及び結晶成長部の長さ（L2）に相当する長さの延長断熱領域を有しており、坩堝と側面断熱部材とを坩堝高さ方向に相対的に移動させ、前記基断熱領域の全てを前記延長断熱領域に更新しながら炭化珪素単結晶インゴットを製造することを特徴とする前記(4)に記載の炭化珪素単結晶インゴットの製造方法。
(6) 前記側面断熱部材の延長断熱領域が、前記側面断熱部材の基断熱領域の下方側に位置しており、坩堝に対して側面断熱部材を相対的に上昇させ、前記基断熱領域のうちの少なくとも前記原料対応断熱領域を延長断熱領域に更新しながら炭化珪素単結晶インゴットを製造する前記(4)又は(5)に記載の炭化珪素単結晶インゴットの製造方法。
(7) 前記側面断熱部材を坩堝高さ方向に連続的に移動させ、前記基断熱領域のうちの少なくとも前記原料対応断熱領域を延長断熱領域に更新させる前記(4)〜(6)のいずれかに記載の炭化珪素単結晶インゴットの製造方法。 (4) A raw material loading portion in which a silicon carbide raw material is loaded, a pit having a crystal growth portion in which a silicon carbide single crystal ingot grows, and a side heat insulating member arranged so as to surround the outer peripheral side surface of the pit are provided. A silicon carbide single crystal ingot is produced by a sublimation recrystallization method in which the sublimation gas generated by heating the silicon carbide raw material in the raw material loading section is recrystallized on the seed crystal of the crystal growth section using a manufacturing apparatus. In the meantime
The crucible and the side heat insulating member are provided with a moving mechanism for relatively moving in the crucible height direction, and the side heat insulating member is located on the side of the crucible to insulate the raw material loading portion and the crystal growth portion. Using a manufacturing apparatus provided with an extended heat insulating region having a length corresponding to at least the length (L1) of the raw material loading portion of the crucible in the crucible height direction in addition to the basic heat insulating region.
The crucible and the side heat insulating member are relatively moved, and the raw material corresponding heat insulating region that is located at least on the side of the raw material loading portion and insulates the raw material loading portion in the basic heat insulating region of the side heat insulating member is extended heat insulating. A method for producing a silicon carbide single crystal ingot, which comprises producing a silicon carbide single crystal ingot while updating to a region.
(5) In addition to the basic heat insulating region located on the side of the crucible, the side heat insulating member is an extended heat insulating member having a length corresponding to the length (L2) of the raw material loading portion and the crystal growth portion of the crucible in the crucible height direction. It has a region, and the crucible and the side heat insulating member are relatively moved in the crucible height direction, and the silicon carbide single crystal ingot is manufactured while updating all of the basic heat insulating region to the extended heat insulating region. The method for producing a silicon carbide single crystal ingot according to (4) above.
(6) The extended heat insulating region of the side heat insulating member is located below the basic heat insulating region of the side heat insulating member, and the side heat insulating member is raised relative to the crucible to be included in the basic heat insulating region. The method for producing a silicon carbide single crystal ingot according to (4) or (5) above, wherein at least the heat insulating region corresponding to the raw material is updated to an extended heat insulating region.
(7) Any of the above (4) to (6), wherein the side heat insulating member is continuously moved in the crucible height direction, and at least the raw material corresponding heat insulating region in the basic heat insulating region is updated to the extended heat insulating region. The method for producing a silicon carbide single crystal ingot according to.

本発明の炭化珪素単結晶インゴットの製造装置によれば、坩堝の外周側面の断熱部材を更新させながら結晶成長の操業を行うことが可能となり、結晶成長中に坩堝外に漏出する原料ガスが坩堝の外周側面で断熱部材に析出し、坩堝の外周側面に対する断熱性能が低下し、坩堝内部の温度条件が変動することを可及的に低減でき、坩堝内部の温度分布の制御性を向上させることができる。
また、坩堝の外周側面の断熱部材における断熱性能低下の問題を回避することができるので、坩堝の原料装填部内の炭化珪素原料を効率的に加熱して昇華させることが可能になり、大口径かつ長尺の炭化珪素単結晶インゴットを製造する際の再現性が向上して歩留りが向上する。
更に、本発明の炭化珪素単結晶インゴットの製造方法によれば、高品質な炭化珪素単結晶インゴットの製造が可能になり、この高品質な炭化珪素単結晶インゴットを用いて電子材料用の炭化珪素単結晶基板を製造すれば、炭化珪素原料に対して製造される基板の歩留りが向上し、炭化珪素単結晶基板のコスト低減を図ることができる。 According to the silicon carbide single crystal ingot manufacturing apparatus of the present invention, it is possible to operate the crystal growth while updating the heat insulating member on the outer peripheral side surface of the crucible, and the raw material gas leaking to the outside of the crucible during the crystal growth is the crucible. It can be deposited on the heat insulating member on the outer peripheral side surface of the crucible, the heat insulating performance on the outer peripheral side surface of the crucible is lowered, the fluctuation of the temperature condition inside the crucible can be reduced as much as possible, and the controllability of the temperature distribution inside the crucible is improved. Can be done.
Further, since it is possible to avoid the problem of deterioration of the heat insulating performance of the heat insulating member on the outer peripheral side surface of the crucible, it becomes possible to efficiently heat and sublimate the silicon carbide raw material in the raw material loading portion of the crucible, resulting in a large diameter and a large diameter. Reproducibility and yield are improved when manufacturing a long silicon carbide single crystal ingot.
Further, according to the method for producing a silicon carbide single crystal ingot of the present invention, it is possible to produce a high-quality silicon carbide single crystal ingot, and the high-quality silicon carbide single crystal ingot can be used to produce silicon carbide for electronic materials. If the single crystal substrate is manufactured, the yield of the manufactured substrate with respect to the silicon carbide raw material can be improved, and the cost of the silicon carbide single crystal substrate can be reduced.

図１は、本発明の実施例に係る炭化珪素単結晶インゴットの製造装置全体を概念的に示す説明図である。FIG. 1 is an explanatory diagram conceptually showing the entire apparatus for manufacturing a silicon carbide single crystal ingot according to an embodiment of the present invention. 図２は、図１の坩堝に対する断熱部材の移動距離を説明するための説明図である。FIG. 2 is an explanatory diagram for explaining the moving distance of the heat insulating member with respect to the crucible of FIG. 図３は、図１の坩堝に対する断熱部材の移動方法を説明するための説明図である。FIG. 3 is an explanatory diagram for explaining a method of moving the heat insulating member with respect to the crucible of FIG. 図４は、改良レーリー法の原理を説明するための説明図である。FIG. 4 is an explanatory diagram for explaining the principle of the improved Rayleigh method.

以下、添付図面に示す実施例に基づいて、本発明の炭化珪素単結晶インゴットの製造装置、及びこの製造装置を用いて炭化珪素単結晶インゴットを製造する炭化珪素単結晶インゴットの製造方法の実施の形態を説明する。 Hereinafter, based on the examples shown in the attached drawings, the apparatus for producing a silicon carbide single crystal ingot of the present invention and the method for producing a silicon carbide single crystal ingot for producing a silicon carbide single crystal ingot using this manufacturing apparatus will be implemented. The form will be described.

図１は、本発明の実施例に係る炭化珪素単結晶インゴットの製造装置の全体が示されており、この製造装置において、二重石英管13内には黒鉛製坩堝１（以下、「坩堝」と略称する。）とこの坩堝１を取り囲むように覆う黒鉛製の断熱部材５とが配設されている。そして、前記坩堝１は、開口部を有して円筒状（上端開口筒状）に形成された黒鉛製の坩堝本体1aとその上端の開口部を閉塞する黒鉛製の坩堝上蓋1bとで構成されて、その下部が原料装填部1cになっていると共にその上部が結晶成長部1dとなっている。また、前記原料装填部1c内には炭化珪素原料（以下、単に「原料」という場合がある。）３が装填されており、また、前記坩堝上蓋1bの内面には炭化珪素単結晶からなる種結晶２が取り付けられている。更に、坩堝１を取り囲むように覆う断熱部材５は、坩堝１の側面を覆う側面断熱部材５aと、坩堝１の下面を覆う断熱部材5bと、坩堝１の上面（すなわち、坩堝上蓋1bの上面）を覆う断熱部材5cとで構成されており、前記側面断熱部材1aは、坩堝１、断熱部材1b、及び断熱部材5cに対して相対的に移動可能なように分離されている。 FIG. 1 shows the entire manufacturing apparatus for a silicon carbide single crystal ingot according to an embodiment of the present invention. In this manufacturing apparatus, a graphite crucible 1 (hereinafter, “crucible”) is contained in a double quartz tube 13. (Abbreviated as) and a graphite heat insulating member 5 that surrounds and covers the crucible 1. The crucible 1 is composed of a graphite crucible body 1a having an opening and formed in a cylindrical shape (upper end opening tubular shape) and a graphite crucible top lid 1b that closes the upper end opening. The lower part is the raw material loading part 1c, and the upper part is the crystal growth part 1d. Further, a silicon carbide raw material (hereinafter, may be simply referred to as “raw material”) 3 is loaded in the raw material loading unit 1c, and a seed made of silicon carbide single crystal is loaded on the inner surface of the crucible upper lid 1b. Crystal 2 is attached. Further, the heat insulating member 5 that covers the crucible 1 so as to surround the crucible 1 includes a side heat insulating member 5a that covers the side surface of the crucible 1, a heat insulating member 5b that covers the lower surface of the crucible 1, and an upper surface of the crucible 1 (that is, the upper surface of the crucible upper lid 1b). The side heat insulating member 1a is separated from the crucible 1, the heat insulating member 1b, and the heat insulating member 5c so as to be relatively movable.

この実施例において、前記坩堝１、断熱部材1b、及び断熱部材5cは坩堝支持体10の上に配置されており、また、坩堝の外周側面を覆う断熱部材5aは断熱部材支持機構11の上に配置されおり、この断熱部材支持機構11には側面断熱部材5aを坩堝１に対して上下方向に移動させる駆動機構12が設けられている。
なお、この図１において、符号６は坩堝上蓋1b上面を覆う断熱部材5cに形成されている切欠き孔であり、符号13は二重石英管を示し、符号14は真空排気装置を示し、符号15はArガス配管を示し、符号16はArガス用マスフローコントローラを示し、符号17は発熱部材として機能する前記坩堝１を発熱させるための高周波誘導加熱用のワークコイルを示し、このワークコイル17には高周波電流を流すための図示外の高周波電源が取り付けられている。 In this embodiment, the crucible 1, the heat insulating member 1b, and the heat insulating member 5c are arranged on the crucible support 10, and the heat insulating member 5a covering the outer peripheral side surface of the crucible is placed on the heat insulating member support mechanism 11. The heat insulating member support mechanism 11 is provided with a drive mechanism 12 for moving the side heat insulating member 5a in the vertical direction with respect to the crucible 1.
In FIG. 1, reference numeral 6 is a notch hole formed in the heat insulating member 5c covering the upper surface of the coil upper lid 1b, reference numeral 13 indicates a double quartz tube, and reference numeral 14 indicates a vacuum exhaust device. Reference numeral 15 indicates an Ar gas pipe, reference numeral 16 indicates a mass flow controller for Ar gas, and reference numeral 17 indicates a work coil for high-frequency induction heating for heating the vacuum 1 functioning as a heat generating member. Is equipped with a high-frequency power supply (not shown) for passing high-frequency current.

この製造装置において、二重石英管13内部は、真空排気装置14により高真空排気（10^-3Pa以下）することができ、かつArガス配管15とArガス用マスフローコントローラ16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ようになっている。そして、坩堝１の温度の計測は、坩堝１の上下部を覆う黒鉛製の断熱部材５の中央部にそれぞれ光路を設け、坩堝１の上部（坩堝上蓋1b）及び下部〔坩堝本体1a下部の原料装填部1cの底壁部（坩堝底壁部）〕からの光を取り出し、二色温度計を用いて行われ、坩堝１下部の温度から原料温度を判断し、また、坩堝１上部の温度から種結晶２の温度を判断している。 In this manufacturing apparatus, the inside of the double quartz tube 13 ^{can be highly evacuated (10 -3} Pa or less) by the vacuum exhaust device 14, and inside by using the Ar gas pipe 15 and the mass flow controller 16 for Ar gas. The pressure of the atmosphere can be controlled by Ar gas. Then, the temperature of the crucible 1 is measured by providing optical paths in the central portion of the graphite heat insulating member 5 that covers the upper and lower parts of the crucible 1, and the upper part (crucible upper lid 1b) and the lower part [raw material of the lower part of the crucible body 1a]. Light from the bottom wall of the loading section 1c (crucible bottom wall)] is taken out and performed using a two-color thermometer to determine the raw material temperature from the temperature at the bottom of the crucible 1 and from the temperature at the top of the crucible 1. The temperature of the seed crystal 2 is determined.

ここで、種結晶２上に炭化珪素単結晶の結晶成長させるためには、坩堝１内部の上下方向に温度勾配を形成し、原料装填部1cの温度を高くし、原料３と種結晶２との間に所定の温度勾配が形成されるように、結晶成長部1d側の温度を相対的に低くする必要がある。しかしながら、前述の通り、昇華再結晶法を用いた結晶成長においては、昇華ガスが坩堝１から漏れ出してこの坩堝１の外周側面に配置された側面断熱部材5aで析出し、若しくは、反応生成物を形成して断熱部材の断熱性能低下を引き起こすが、この断熱性能低下は、より高温の原料装填部近傍で大きく、このことに起因して原料と結晶との間の温度差が小さくなって結晶成長に悪影響を与える。 Here, in order to grow the silicon carbide single crystal on the seed crystal 2, a temperature gradient is formed in the vertical direction inside the pit 1, the temperature of the raw material loading portion 1c is raised, and the raw material 3 and the seed crystal 2 are formed. It is necessary to make the temperature on the crystal growth portion 1d side relatively low so that a predetermined temperature gradient is formed between the two. However, as described above, in the crystal growth using the sublimation recrystallization method, the sublimation gas leaks from the pit 1 and is precipitated by the side heat insulating member 5a arranged on the outer peripheral side surface of the pit 1, or the reaction product. The heat insulating performance of the heat insulating member deteriorates due to the fact that the heat insulating performance deteriorates significantly in the vicinity of the raw material loading portion at a higher temperature, and as a result, the temperature difference between the raw material and the crystal becomes smaller and the crystal grows. It adversely affects growth.

そこで、この実施例においては、図１〜図３に示すように、前記坩堝１と側面断熱部材5aとを坩堝高さ方向に相対的に移動させる移動機構12が設けられていると共に、側面断熱部材5aには、坩堝１の側方に位置して原料装填部1c及び結晶成長部1dを断熱する基断熱領域Ａbに加えて、坩堝高さ方向に少なくとも坩堝１の原料装填部1cの長さ（L1）に相当する長さの延長断熱領域Ａeが設けられており、これによって、炭化珪素単結晶インゴットの製造過程において、前記移動機構12により、坩堝１と側面断熱部材5aとを相対的に移動させ、坩堝側方に位置して原料装填部1c及び結晶成長部1dを断熱する側面断熱部材5aの基断熱領域Ａbのうち、少なくとも原料装填部1cの側方に位置してこの原料装填部1cを断熱する原料対応断熱領域部分を延長断熱領域Ａeで更新しつつ結晶成長を行うことができるようになっている。 Therefore, in this embodiment, as shown in FIGS. 1 to 3, a moving mechanism 12 for relatively moving the crucible 1 and the side heat insulating member 5a in the crucible height direction is provided, and side heat insulation is provided. In addition to the basic heat insulating region Ab that is located on the side of the crucible 1 and insulates the raw material loading portion 1c and the crystal growth portion 1d, the member 5a has at least the length of the raw material loading portion 1c of the crucible 1 in the crucible height direction. An extended heat insulating region Ae having a length corresponding to (L1) is provided, whereby the crucible 1 and the side heat insulating member 5a are relatively separated by the moving mechanism 12 in the manufacturing process of the silicon carbide single crystal ingot. Of the basic heat insulating region Ab of the side heat insulating member 5a that is moved and is located on the side of the crucible to insulate the raw material loading portion 1c and the crystal growth portion 1d, the raw material loading portion is located at least on the side of the raw material loading portion 1c. It is possible to carry out crystal growth while updating the portion of the heat insulating region corresponding to the raw material that insulates 1c with the extended heat insulating region Ae.

ここで、側面断熱部材5aにおいて、その基断熱領域Ａbに延設する延長断熱領域Ａeの長さ(L)については、少なくとも坩堝１の原料装填部1cの長さ(L1)の分があればよく、その長さの上限については特に制限はないが、原料装填部1c及び結晶成長部1dの長さ（L2）に相当する長さを超えてあまり長くすると、有効に機能しない断熱領域が生じて不経済であり、結晶成長条件の再現性や断熱材のコストの観点からは、好ましくは原料装填部1c及び結晶成長部1dの長さ（L2）に相当する長さ（すなわち、基断熱領域Ａbの長さ）、あるいはこの基断熱領域Ａbの長さに加えて、基断熱領域Ａbの全体が確実に延長断熱領域Ａeで更新されるように若干の余裕を持たせた長さとするのがよい。 Here, in the side heat insulating member 5a, the length (L) of the extended heat insulating region Ae extending to the basic heat insulating region Ab is at least as long as the length (L1) of the raw material loading portion 1c of the pit 1. Often, the upper limit of the length is not particularly limited, but if it is made too long beyond the length (L2) corresponding to the length (L2) of the raw material loading portion 1c and the crystal growth portion 1d, a heat insulating region that does not function effectively occurs. It is uneconomical, and from the viewpoint of reproducibility of crystal growth conditions and cost of heat insulating material, it is preferable to have a length corresponding to the length (L2) of the raw material loading part 1c and the crystal growing part 1d (that is, the basic heat insulating region). The length of Ab), or in addition to the length of this basic heat insulating region Ab, the length should be set with some allowance so that the entire basic heat insulating region Ab is surely updated by the extended heat insulating region Ae. good.

そして、前記移動機構12による坩堝１と側面断熱部材5aとの間の相対的な移動は、側面断熱部材の延長断熱領域をその基断熱領域の下方側に延設し、坩堝１及び／又は側面断熱部材5aを移動させることにより、坩堝に対して側面断熱部材が相対的に上昇するように移動させて更新するのがよく、これによって原料装填部1cの側方に位置する基断熱領域Ａbの原料対応断熱領域部分を先に延長断熱領域Ａeで更新することができ、原料装填部1c内の炭化珪素原料３側と結晶成長部1d内の種結晶２側との間の温度差（温度勾配）をより確実に適切な値に制御することができる。 Then, the relative movement between the crucible 1 and the side heat insulating member 5a by the moving mechanism 12 extends the extended heat insulating region of the side heat insulating member to the lower side of the basic heat insulating region, and the crucible 1 and / or the side surface thereof. By moving the heat insulating member 5a, it is preferable to move and update the side heat insulating member so that the side heat insulating member rises relative to the crucible, whereby the basic heat insulating region Ab located on the side of the raw material loading portion 1c The heat insulating region corresponding to the raw material can be updated in the extended heat insulating region Ae first, and the temperature difference (temperature gradient) between the silicon carbide raw material 3 side in the raw material loading portion 1c and the seed crystal 2 side in the crystal growth portion 1d. ) Can be controlled to an appropriate value more reliably.

ここで、上記移動機構12により坩堝１と側面断熱部材5aとの間を相対的に移動させる方法について、図２及び図３に基づいて、側面断熱部材5aを坩堝１に対して下から上に移動させる場合を例にして以下に更に詳細に説明する。
図３において、結晶成長中に側面断熱部材5aをその移動開始位置(P_S)から移動終了位置(P_F)まで移動させるが、この際に側面断熱部材5aがその基断熱領域Ａbの下方側に長さ(L)の延長断熱領域Ａeを有すると、この延長断熱領域Ａeは、側面断熱部材5aが上昇する間に上昇し、図３(a)の位置から図３(b)の位置まで移動し、側面断熱部材5aの基断熱領域Ａbについて下から長さ(L)の分だけ更新することになり、この長さ(L)は面断熱部材5aの移動距離に相当する。 Here, regarding a method of relatively moving between the crucible 1 and the side heat insulating member 5a by the moving mechanism 12, the side heat insulating member 5a is moved from bottom to top with respect to the crucible 1 based on FIGS. 2 and 3. The case of moving the crucible will be described in more detail below.
3, but is moved crystal growth during the movement start position side heat insulating member 5a from (P _S) to the movement end position (P _F), the side surface heat insulating member 5a when this is the lower side of the base insulation region Ab When a length (L) extended heat insulating region Ae is provided, the extended heat insulating region Ae rises while the side heat insulating member 5a rises from the position of FIG. 3 (a) to the position of FIG. 3 (b). It moves and updates the basic heat insulating region Ab of the side heat insulating member 5a by the length (L) from the bottom, and this length (L) corresponds to the moving distance of the surface heat insulating member 5a.

そして、この際に側面断熱部材5aを移動させる方法については、間欠的に移動を行うと、基断熱領域Ａbが延長断熱領域Ａeで更新される速度が変化することになり、坩堝側面から放出される熱量が基断熱領域Ａbにおいて不連続的に変化することになる。その結果、原料と種結晶側との間の温度差（温度勾配）に不連続な変化が誘発され、結晶成長の間に温度勾配の状態が変化し、形成される炭化ケイ素単結晶インゴットに欠陥の導入や異種ポリタイプの発生が起こり易くなる。このため、側面断熱部材5aは連続的に移動させることが好ましい。 As for the method of moving the side heat insulating member 5a at this time, if the side heat insulating member 5a is moved intermittently, the speed at which the basic heat insulating region Ab is updated in the extended heat insulating region Ae changes, and the side heat insulating member 5a is released from the crucible side surface. The amount of heat generated will change discontinuously in the basic adiabatic region Ab. As a result, a discontinuous change is induced in the temperature difference (temperature gradient) between the raw material and the seed crystal side, the state of the temperature gradient changes during crystal growth, and the silicon carbide single crystal ingot formed is defective. And the occurrence of heterogeneous polytypes are likely to occur. Therefore, it is preferable that the side heat insulating member 5a is continuously moved.

また、結晶成長の全成長時間をかけて側面断熱部材5aを連続的に移動させる際の速度の設定については、坩堝１内に形成される前記温度勾配等に応じて、複数考えられる。例えば、制御のし易さから、一定速度で移動させることも有効であり、この場合には、移動速度を例えば移動距離／全成長時間（L／h）に設定することができる。また、漏出ガスによる断熱部材の劣化は、結晶成長中に蓄積され、その後半でより断熱性能の低下が生じるので、この断熱部材において断熱性能が低下する傾向を考慮して、例えば、結晶成長の前半の速度を比較的遅くし、後半の速度を比較的速くしたり、また、前半と後半の中間で中間の速度を採用したり、更には、結晶成長の開始から終了までの間に連続して速度を速める速度勾配を設けることも可能である。装置の形状を勘案して、移動速度を０．５mm/h以上１０mm/h以下の範囲に設定するのが好ましい。 Further, there are a plurality of possible settings for the speed at which the side heat insulating member 5a is continuously moved over the entire growth time of crystal growth, depending on the temperature gradient and the like formed in the crucible 1. For example, it is effective to move at a constant speed from the viewpoint of ease of control. In this case, the moving speed can be set to, for example, moving distance / total growth time (L / h). Further, the deterioration of the heat insulating member due to the leaked gas is accumulated during the crystal growth, and the heat insulating performance is further deteriorated in the latter half. Therefore, in consideration of the tendency that the heat insulating performance is lowered in this heat insulating member, for example, the crystal growth The speed of the first half is relatively slow, the speed of the second half is relatively high, the middle speed is adopted between the first half and the second half, and further, it is continuous from the start to the end of crystal growth. It is also possible to provide a speed gradient to increase the speed. Considering the shape of the device, it is preferable to set the moving speed in the range of 0.5 mm / h or more and 10 mm / h or less.

特に、本発明の製造装置を用いて、成長高さが４０mm以上１００mm以下の炭化珪素単結晶インゴットを製造した場合には、坩堝１内に装填した炭化珪素原料３を再現性良く昇華させることができ、また、結晶成長中の結晶成長速度の変動が小さくなって高品質の炭化珪素単結晶を製造することができる。このため、電子材料用途に好適な炭化珪素単結晶を効率良く作製することが可能になり、炭化珪素単結晶インゴットをより安価に製造することができる。 In particular, when a silicon carbide single crystal ingot having a growth height of 40 mm or more and 100 mm or less is produced using the production apparatus of the present invention, the silicon carbide raw material 3 loaded in the crucible 1 can be sublimated with good reproducibility. In addition, the fluctuation of the crystal growth rate during crystal growth is reduced, and a high-quality silicon carbide single crystal can be produced. Therefore, it becomes possible to efficiently produce a silicon carbide single crystal suitable for use as an electronic material, and it is possible to produce a silicon carbide single crystal ingot at a lower cost.

以下、上記の図１〜図３に示した実施例の炭化珪素インゴットの製造装置を用いて、炭化珪素インゴットを製造した際の製造例について説明する。
〔製造例１〕
側面断熱部材については、延長断熱領域の長さが坩堝の原料装填部及び結晶成長部の高さ（L2）に相当する長さ（移動距離：Ｌ）を有する構造とした。
坩堝の原料装填部内には、アチソン法により作製された炭化珪素結晶粉末からなる炭化珪素原料２．６kgを充填し、また、坩堝の坩堝上蓋には、種結晶として、口径１０５mmの(0001)面を有する４Ｈポリタイプの炭化珪素単結晶ウェハを配置した。 Hereinafter, a manufacturing example when the silicon carbide ingot is manufactured by using the silicon carbide ingot manufacturing apparatus of the examples shown in FIGS. 1 to 3 will be described.
[Manufacturing Example 1]
The side heat insulating member has a structure in which the length of the extended heat insulating region has a length (moving distance: L) corresponding to the height (L2) of the raw material loading portion and the crystal growth portion of the crucible.
The raw material loading part of the crucible is filled with 2.6 kg of a silicon carbide raw material made of silicon carbide crystal powder produced by the Achison method, and the crucible top lid of the crucible is a (0001) surface having a diameter of 105 mm as a seed crystal. A 4H polytype silicon carbide single crystal wafer having a crucible was placed.

このようにして準備された坩堝を、図１に示すように、二重石英管の内部に設置し、原料温度を目標温度である２３００℃まで上昇させた後、二重石英管内のＡrの圧力を成長圧力１．３kPaまで３０分かけて減圧し、原料を昇華させて種結晶の表面で炭化珪素単結晶を成長させる結晶成長を開始させ、加熱を１４０時間継続して炭化珪素単結晶インゴットを製造した。
側面断熱部材については、この結晶成長を行っている１４０時間に亘り、坩堝に対して上方に連続的に移動をさせ、また、その移動速度については、前半の７０時間で移動距離Ｌ(L2)の１／３が移動するように設定し、後半の７０時間で移動距離Ｌ(L2)の２／３が移動するように設定した。 As shown in FIG. 1, the crucible prepared in this way is installed inside the double quartz tube, the raw material temperature is raised to the target temperature of 2300 ° C., and then the pressure of Ar in the double quartz tube is reached. The pressure was reduced to a growth pressure of 1.3 kPa over 30 minutes, the raw material was sublimated to start crystal growth in which a silicon carbide single crystal was grown on the surface of the seed crystal, and heating was continued for 140 hours to form a silicon carbide single crystal ingot. Manufactured.
The side heat insulating member is continuously moved upward with respect to the crucible for 140 hours during this crystal growth, and the moving speed is the moving distance L (L2) in the first 70 hours. 1/3 of the movement was set to move, and 2/3 of the movement distance L (L2) was set to move in the latter 70 hours.

この炭化珪素単結晶インゴットの製造を１０回繰り返して行ったところ、平均で口径１０５mm及びインゴット高さ５５mmの炭化珪素単結晶インゴットが得られた。結晶の高さの変動は±５％以内であって、結晶成長を再現性良く行うことができた。また、Ｘ線回折及びラマン散乱により分析したところ、そのうち８回の結晶成長において、狙いの４Ｈポリタイプの結晶であってマイクロパイプ等の結晶欠陥が少なく、極めて高品質であることが確認された。また、それ以外の２回の結晶成長では、その前半成長部分に異種ポリタイプ（6H等）が認められた。 When the production of this silicon carbide single crystal ingot was repeated 10 times, a silicon carbide single crystal ingot having an average diameter of 105 mm and an ingot height of 55 mm was obtained. The variation in crystal height was within ± 5%, and crystal growth could be performed with good reproducibility. Further, as a result of analysis by X-ray diffraction and Raman scattering, it was confirmed that the target 4H polytype crystal had few crystal defects such as micropipes and was extremely high quality in eight crystal growths. .. In the other two crystal growths, a heterogeneous polytype (6H, etc.) was observed in the first half of the crystal growth.

本発明を適用することにより、製造されるインゴット高さのばらつきを低減できることを確認し、また、側面断熱部材の劣化に伴って結晶成長を繰り返すたびに発生する坩堝内部の温度勾配の変動を低減できることを確認した。複数回の結晶成長を繰り返す際に坩堝内部の温度勾配を再現性良く実現させることにより、結晶品質の劣化の原因である異種ポリタイプが混入する頻度を顕著に低減することができ、結晶成長の歩留り向上を達成することができた。更に、本発明を適用することで、電子デバイスを作製するための基板を製造する上で必要な良質の４Ｈ炭化珪素単結晶を歩留り良く製造できることが判明した。 By applying the present invention, it has been confirmed that the variation in the height of the manufactured ingot can be reduced, and the variation in the temperature gradient inside the crucible that occurs every time the crystal growth is repeated due to the deterioration of the side heat insulating member is reduced. I confirmed that I could do it. By realizing the temperature gradient inside the crucible with good reproducibility when repeating crystal growth multiple times, the frequency of mixing of different polytypes, which is the cause of deterioration of crystal quality, can be significantly reduced, and crystal growth can occur. We were able to achieve an improvement in yield. Furthermore, it has been found that by applying the present invention, it is possible to produce a high-quality 4H silicon carbide single crystal necessary for producing a substrate for producing an electronic device with a high yield.

〔製造例２〕
側面断熱部材の延長断熱領域の長さを坩堝の原料装填部の高さ（L1）に相当する長さ（移動距離：Ｌ）とし、坩堝の原料装填部内には炭化珪素原料５．０kgを充填し、また、種結晶として口径１５５mmの(0001)面を有する４Ｈポリタイプの炭化珪素単結晶ウェハを用い、更に、結晶成長時間を１６０時間とすると共に、移動速度を全体の１６０時間で移動距離Ｌ(L1)を移動するように設定したこと以外については、上記製造例１の場合とした。 [Manufacturing Example 2]
The length of the extended heat insulating region of the side heat insulating member is set to the length (moving distance: L) corresponding to the height (L1) of the raw material loading portion of the crucible, and 5.0 kg of silicon carbide raw material is filled in the raw material loading portion of the crucible. Further, a 4H polytype silicon carbide single crystal wafer having a (0001) plane with a diameter of 155 mm is used as a seed crystal, the crystal growth time is set to 160 hours, and the moving speed is set to the total moving distance of 160 hours. Except for the fact that L (L1) was set to move, the case of Production Example 1 was used.

製造例１の場合と同様にこの炭化珪素単結晶インゴットの製造を１０回繰り返して行ったところ、平均で口径１５５mm及びインゴット高さ６５mm（高さ変動±５％以内）の炭化珪素単結晶インゴットが得られた。また、Ｘ線回折及びラマン散乱により分析したところ、そのうち８回の結晶成長において、狙いの４Ｈポリタイプの結晶であってマイクロパイプ等の結晶欠陥が少なく、極めて高品質であることが確認された。また、それ以外の２回の結晶成長では、その前半成長部分に異種ポリタイプ（6H等）が認められた。
また、製造例１の場合と同様に、インゴット高さのばらつき低減、結晶成長毎の温度勾配変動の低減、及び坩堝内部の温度勾配の良好な再現性を確認することができ、また、異種ポリタイプ混入頻度の低減、結晶成長の歩留り向上、及び良質な４Ｈ炭化珪素単結晶の歩留り向上を確認することができた。 When this silicon carbide single crystal ingot was manufactured 10 times in the same manner as in Production Example 1, a silicon carbide single crystal ingot having an average diameter of 155 mm and an ingot height of 65 mm (within a height variation of ± 5%) was obtained. Obtained. Further, as a result of analysis by X-ray diffraction and Raman scattering, it was confirmed that the target 4H polytype crystal had few crystal defects such as micropipes and was extremely high quality in eight crystal growths. .. In the other two crystal growths, a heterogeneous polytype (6H, etc.) was observed in the first half of the crystal growth.
Further, as in the case of Production Example 1, it is possible to confirm the reduction of the variation in the ingot height, the reduction of the temperature gradient fluctuation for each crystal growth, and the good reproducibility of the temperature gradient inside the crucible. It was confirmed that the frequency of type mixing was reduced, the crystal growth yield was improved, and the yield of high-quality 4H silicon carbide single crystal was improved.

〔比較製造例１〕
比較製造例１においては、製造例１の場合と同じ側面断熱部材を用い、側面断熱部材を上方に移動させること無く、製造例１の場合と同様にして結晶成長を行った。 [Comparative Manufacturing Example 1]
In Comparative Production Example 1, the same side heat insulating member as in Production Example 1 was used, and crystal growth was carried out in the same manner as in Production Example 1 without moving the side heat insulating member upward.

製造例１の場合と同様にこの炭化珪素単結晶インゴットの製造を１０回繰り返して行ったところ、平均で口径１０５mm及びインゴット高さ５１mm（高さ変動±１０％以内）の炭化珪素単結晶インゴットが得られ、再現性に劣っており、また、インゴット高さが低くて歩留りに劣っていた。また、Ｘ線回折及びラマン散乱により分析したところ、そのうち６回の結晶成長において、狙いの４Ｈポリタイプの結晶であってマイクロパイプ等の結晶欠陥が少ない高品質であることが確認されたが、それ以外の４回の結晶成長ではその前半成長部分に異種ポリタイプ（6H等）が認められた。また、製造例１の場合とは異なり、インゴット高さのばらつきが多く、結晶成長の再現性に劣っていた。また、結晶成長毎のばらつきに起因した坩堝内部の温度勾配の変動が認められ、異種ポリタイプの発生の頻度が高く、結晶成長の歩留りが低かった。 When the production of this silicon carbide single crystal ingot was repeated 10 times in the same manner as in the case of Production Example 1, a silicon carbide single crystal ingot having an average diameter of 105 mm and an ingot height of 51 mm (within a height variation of ± 10%) was obtained. It was obtained and was inferior in reproducibility, and the ingot height was low and the yield was inferior. Further, as a result of analysis by X-ray diffraction and Raman scattering, it was confirmed that the target 4H polytype crystal was of high quality with few crystal defects such as micropipes in 6 crystal growths. In the other four crystal growths, heterogeneous polytypes (6H, etc.) were observed in the first half of the crystal growth. Further, unlike the case of Production Example 1, there were many variations in the height of the ingot, and the reproducibility of crystal growth was inferior. In addition, fluctuations in the temperature gradient inside the crucible due to variations in each crystal growth were observed, the frequency of occurrence of heterogeneous polytypes was high, and the yield of crystal growth was low.

１…黒鉛製坩堝（坩堝）、1a…坩堝本体、1b…坩堝上蓋、1c…原料装填部、1d…結晶成長部、２…種結晶、３…炭化珪素原料（原料）、４…、５,5b,5c…断熱部材、5a…側面断熱部材、６…切欠き孔、10…坩堝支持体、11…断熱部材支持機構、12…駆動機構、13…二重石英管、14…真空排気装置、15…Arガス配管、16…Arガス用マスフローコントローラ、17…ワークコイル。 1 ... Graphite crucible (crucible), 1a ... Crucible body, 1b ... Crucible top lid, 1c ... Raw material loading part, 1d ... Crystal growth part, 2 ... Seed crystal, 3 ... Silicon carbide raw material (raw material), 4 ... 5, 5b, 5c ... Insulation member, 5a ... Side insulation member, 6 ... Notch hole, 10 ... Crucible support, 11 ... Insulation member support mechanism, 12 ... Drive mechanism, 13 ... Double quartz tube, 14 ... Vacuum exhaust device, 15 ... Ar gas piping, 16 ... Ar gas mass flow controller, 17 ... work coil.

Claims

A raw material loading portion on which a silicon carbide raw material is loaded, a pit having a crystal growth portion on which a silicon carbide single crystal ingot grows, and a side heat insulating member arranged so as to surround the outer peripheral side surface of the pit are provided, and the raw material loading is provided. In a silicon carbide single crystal ingot manufacturing apparatus that manufactures a silicon carbide single crystal ingot by a sublimation recrystallization method in which the sublimation gas generated by heating the silicon carbide raw material in the part is recrystallized on the seed crystal of the crystal growth part. ,
A moving mechanism for relatively moving the crucible and the side surface heat insulating member in the crucible height direction is provided, and the side surface heat insulating member is located on the side of the crucible to insulate the raw material loading portion and the crystal growth portion. In addition to the basic heat insulating region, an extended heat insulating region having a length corresponding to at least the height (L1) of the raw material loading portion of the crucible is provided in the crucible height direction.
In the manufacturing process of the silicon carbide single crystal ingot, the crucible and the side heat insulating member are relatively moved by the moving mechanism, and the crucible and the side heat insulating member are located at least on the side of the raw material loading portion in the basic heat insulating region of the side heat insulating member. The raw material-compatible heat insulating area that insulates the raw material loading part can be updated to the extended heat insulating area .
The extended heat insulating region of the side heat insulating member is located below the basic heat insulating region of the side heat insulating member, and by raising the side heat insulating member relative to the crucible, the influence of deterioration due to the gas leaking from the crucible An apparatus for producing a silicon carbide single crystal ingot, which comprises updating at least the raw material-corresponding heat insulating region of the basic heat insulating region to an extended heat insulating region.

In addition to the basic heat insulating region located on the side of the crucible, the side heat insulating member is provided with an extended heat insulating region having a length corresponding to the height (L2) of the raw material loading portion and the crystal growth portion of the crucible. In the process of manufacturing the silicon carbide single crystal ingot, the crucible and the side heat insulating member are relatively moved in the crucible height direction, and the entire basic heat insulating region can be renewed to the extended heat insulating region. The apparatus for producing a silicon carbide single crystal ingot according to claim 1.

A manufacturing apparatus including a raw material loading portion in which a silicon carbide raw material is loaded, a pit having a crystal growth portion in which a silicon carbide single crystal ingot grows, and a side heat insulating member arranged so as to surround the outer peripheral side surface of the pit. When producing a silicon carbide single crystal ingot by a sublimation recrystallization method in which the sublimation gas generated by heating the silicon carbide raw material in the raw material loading portion is recrystallized on the seed crystal of the crystal growth portion.
The crucible and the side heat insulating member are provided with a moving mechanism for relatively moving in the crucible height direction, and the side heat insulating member is located on the side of the crucible to insulate the raw material loading portion and the crystal growth portion. Using a manufacturing apparatus provided with an extended heat insulating region having a length corresponding to at least the length (L1) of the raw material loading portion of the crucible in the crucible height direction in addition to the basic heat insulating region.
The crucible and the side heat insulating member are relatively moved, and the raw material corresponding heat insulating region that is located at least on the side of the raw material loading portion and insulates the raw material loading portion in the basic heat insulating region of the side heat insulating member is extended heat insulating. Manufacture silicon carbide single crystal ingot while updating to region ,
The extended heat insulating region of the side heat insulating member is located below the basic heat insulating region of the side heat insulating member, raises the side heat insulating member relative to the crucible, and is affected by deterioration due to gas leaking from the crucible. A method for producing a silicon carbide single crystal ingot, which comprises updating at least the raw material-corresponding heat insulating region of the basic heat insulating region to an extended heat insulating region .

In addition to the basic heat insulating region located on the side of the crucible, the side heat insulating member has an extended heat insulating region having a length corresponding to the length (L2) of the raw material loading portion and the crystal growth portion of the crucible in the crucible height direction. The crucible and the side heat insulating member are relatively moved in the crucible height direction, and the silicon carbide single crystal ingot is manufactured while updating the entire basic heat insulating region to the extended heat insulating region. The method for producing a silicon carbide single crystal ingot according to claim 3.

The method for producing a silicon carbide single crystal ingot according to claim 3 or 4 , wherein the crucible and the side heat insulating member are relatively moved over a total growth time.

The method for producing a silicon carbide single crystal ingot according to any one of claims 3 to 5 , wherein the speed at which the crucible and the side heat insulating member are relatively moved is 0.5 mm / h or more and 10 mm / h or less. ..

The carbide according to any one of claims 3 to 6 , wherein the side heat insulating member is continuously moved in the crucible height direction, and at least the raw material corresponding heat insulating region in the basic heat insulating region is renewed to the extended heat insulating region. A method for manufacturing a silicon single crystal ingot.