JP2005179155A - METHOD FOR PRODUCING SiC SINGLE CRYSTAL - Google Patents

METHOD FOR PRODUCING SiC SINGLE CRYSTAL Download PDF

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JP2005179155A
JP2005179155A JP2003425643A JP2003425643A JP2005179155A JP 2005179155 A JP2005179155 A JP 2005179155A JP 2003425643 A JP2003425643 A JP 2003425643A JP 2003425643 A JP2003425643 A JP 2003425643A JP 2005179155 A JP2005179155 A JP 2005179155A
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single crystal
seed crystal
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JP4219800B2 (en
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Tsukuru Gunjishima
造 郡司島
Daisuke Nakamura
大輔 中村
Hiroyuki Kondo
宏行 近藤
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Denso Corp
Toyota Central R&D Labs Inc
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a SiC single crystal by which a high-quality SiC single crystal having a large length and a large diameter can be produced in a short time. <P>SOLUTION: The method for producing a SiC single crystal is carried out by disposing a SiC seed crystal 3 in a growing chamber 4 and growing a bulk SiC single crystal on the growing surface 35. The growing chamber 4 used has a main body 41 where the SiC source material is supplied, an upper lid 42 disposed on the top of the body 41, and a seed housing part 425 formed in the upper lid 42 and recessed outward the growing chamber 4 is used. The SiC seed crystal 3 is embedded in the seed housing part 425 in such a manner that the growing surface 35 opposes to the production source 43 of the SiC source material while the back face 36 in the opposite side to the growing surface 35 is disposed as retreated from the inner surface 421 of the upper lid 42 in the direction away from the production source 43 of the SiC source material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、ＳｉＣ種結晶上にＳｉＣ単結晶を成長させてなるＳｉＣ単結晶の製造方法に関する。   The present invention relates to a method for producing a SiC single crystal obtained by growing a SiC single crystal on a SiC seed crystal.

従来より、ＳｉＣ単結晶を利用するＳｉＣ半導体は、Ｓｉ半導体に代わる次世代パワーデバイスの候補材料として期待されている。高性能なＳｉＣパワーデバイスを実現するためには、高品質かつ大口径で長尺のＳｉＣ単結晶が求められている。
上記ＳｉＣ単結晶は、例えば昇華再析出法やＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）法等により、ＳｉＣ種結晶上にＳｉＣ単結晶を成長させることにより得ることができる。 Conventionally, SiC semiconductors using SiC single crystals have been expected as candidate materials for next-generation power devices that replace Si semiconductors. In order to realize a high-performance SiC power device, a high-quality, large-diameter and long SiC single crystal is required.
The SiC single crystal can be obtained by growing a SiC single crystal on a SiC seed crystal by, for example, a sublimation reprecipitation method or a CVD (Chemical Vapor Deposition) method.

ここで、図１９に、昇華再析出法によりＳｉＣ単結晶を作製する様子を示す。
同図に示すごとく、ＳｉＣ単結晶８０の作製は、例えば坩堝等の成長容器９内で行われる。この成長容器９は、一般に、ＳｉＣ原料粉末９３が供給される本体部９１と、ＳｉＣ種結晶８を保持するための台座９２５が一体的に形成された上蓋９２とを有する。
このような成長容器９内において、ＳｉＣ種結晶８は、ＳｉＣ単結晶８０を成長させるための成長面８５をＳｉＣ原料粉末９３側に向けた状態で上記台座９２５に固定される。そして、この状態で、ＳｉＣ原料粉末９３を加熱して昇華させると、ＳｉＣ種結晶８上にＳｉＣが結晶となって堆積する。このようにして、ＳｉＣ種結晶８上にＳｉＣ単結晶８０を得ることができる。また、このとき、ＳｉＣ単結晶８０の周辺においては、成長容器の内壁や上蓋９２の内表面等から多結晶８９が成長する。 Here, FIG. 19 shows a state in which a SiC single crystal is produced by a sublimation reprecipitation method.
As shown in the figure, the SiC single crystal 80 is produced in a growth vessel 9 such as a crucible. The growth vessel 9 generally has a main body portion 91 to which SiC raw material powder 93 is supplied and an upper lid 92 on which a pedestal 925 for holding the SiC seed crystal 8 is integrally formed.
In such a growth vessel 9, the SiC seed crystal 8 is fixed to the pedestal 925 with the growth surface 85 for growing the SiC single crystal 80 facing the SiC raw material powder 93 side. In this state, when SiC raw material powder 93 is heated and sublimated, SiC is deposited as crystals on SiC seed crystal 8. In this way, SiC single crystal 80 can be obtained on SiC seed crystal 8. At this time, in the vicinity of the SiC single crystal 80, the polycrystal 89 grows from the inner wall of the growth vessel, the inner surface of the upper lid 92, and the like.

ところが、上記のような方法により、ＳｉＣ種結晶８上へのＳｉＣの堆積をさらに続け、ＳｉＣ単結晶の大口径化や長尺化を図ろうとすると、図１９に示すごとく、成長結晶８０の先端部が先細りしてしまう。
良好な成長を継続し、長尺のＳｉＣ単結晶８０を得るためには、単結晶部分の周辺に成長する多結晶８９に比べて単結晶８０からの放熱性を相対的に高く保たなければならないが、ＳｉＣ単結晶８０の成長と共に成長容器９内の温度分布が変化するため、単結晶８０からの放熱性は相対的に低下していく。その結果、単結晶８０の成長速度が低下し、周辺多結晶８９の成長による単結晶部分の先細りや品質劣化が発生するという問題があった。 However, if the SiC single crystal is further deposited on the SiC seed crystal 8 by the above-described method to increase the diameter or length of the SiC single crystal, as shown in FIG. The part will taper off.
In order to continue good growth and obtain a long SiC single crystal 80, the heat dissipation from the single crystal 80 must be kept relatively high compared to the polycrystal 89 grown around the single crystal portion. Although the temperature distribution in the growth vessel 9 changes with the growth of the SiC single crystal 80, the heat dissipation from the single crystal 80 is relatively lowered. As a result, there is a problem that the growth rate of the single crystal 80 is lowered, and the single crystal portion is tapered and the quality is deteriorated due to the growth of the peripheral polycrystal 89.

これまでに開発されている、ＳｉＣ単結晶を長尺化させる方法としては、例えば下記の特許文献１〜３に開示されたものがある。
特許文献１においては、原料を収容する坩堝と種結晶を保持する支持部材とをそれぞれ独立に上下動かつ回転可能にして、原料の温度と単結晶の温度及びその温度差を単結晶の成長中に調整可能にした単結晶育成装置が提案されている。
また、特許文献２においては、種結晶の周りにガイドを設け、ガイド部と単結晶部が常に面一になるように、成長方向と逆方向に種結晶保持部を相対移動させることにより、周囲の多結晶の付着を防止できる単結晶製造装置が提案されている。
さらに、特許文献３においては、周辺に成長した多結晶を一旦除去し、再度成長行う方法が提案されている。 As a method for elongating a SiC single crystal that has been developed so far, for example, there are those disclosed in Patent Documents 1 to 3 below.
In Patent Document 1, a crucible for storing a raw material and a supporting member for holding a seed crystal can be moved up and down independently and rotated, and the temperature of the raw material, the temperature of the single crystal, and the temperature difference between them are being grown. There has been proposed a single crystal growth apparatus which can be adjusted to the above.
Further, in Patent Document 2, a guide is provided around the seed crystal, and by moving the seed crystal holding portion in a direction opposite to the growth direction so that the guide portion and the single crystal portion are always flush with each other, An apparatus for producing a single crystal capable of preventing the adhesion of polycrystals has been proposed.
Furthermore, Patent Document 3 proposes a method in which a polycrystal grown around is removed once and grown again.

しかしながら、特許文献１の方法においては、単結晶の周りに多結晶が生じることを実際上回避できず、単結晶の先細りが発生するおそれがある。また、支持部材の可動時に上記成長容器内に塵が発生し、成長結晶に悪影響を及ぼすおそれがある。また、特許文献２の方法においては、単結晶の周囲に可動部があるため、発生したカーボン微粒子などが成長中の結晶に混入しやすく、結晶品質を劣化させてしまうおそれがある。また、特許文献３の方法においては、周辺多結晶の成長による単結晶部の先細りに対してはある程度の効果があるが、単結晶部の放熱性は成長と共に悪くなり、成長速度が急激に低下するおそれがある。   However, in the method of Patent Document 1, it is practically impossible to avoid the formation of polycrystals around the single crystal, and the single crystal may be tapered. Further, when the support member is moved, dust is generated in the growth vessel, which may adversely affect the growth crystal. Further, in the method of Patent Document 2, since there is a movable part around the single crystal, the generated carbon fine particles and the like are likely to be mixed into the growing crystal, and the crystal quality may be deteriorated. Further, in the method of Patent Document 3, there is a certain effect on the taper of the single crystal part due to the growth of the peripheral polycrystal, but the heat dissipation of the single crystal part deteriorates with the growth, and the growth rate decreases rapidly. There is a risk.

特開平６−２９８５９４号公報JP-A-6-298594 特開２００１−２２６１９７号公報JP 2001-226197 A 特開平６−４８８９８号公報Japanese Patent Laid-Open No. 6-48898

本発明は、かかる従来の問題点に鑑みてなされたものであって、大口径及び長尺の、高品質なＳｉＣ単結晶を短時間で製造できるＳｉＣ単結晶の製造方法を提供しようとするものである。   The present invention has been made in view of such conventional problems, and intends to provide a method for producing a SiC single crystal capable of producing a large-diameter and long-sized high-quality SiC single crystal in a short time. It is.

本発明は、成長容器内にＳｉＣ種結晶を配置し、該ＳｉＣ種結晶の成長面上にバルク状のＳｉＣ単結晶を成長させて、ＳｉＣ単結晶を製造する方法において、
上記成長容器としては、ＳｉＣ原料が供給される本体部とその上部に配置される上蓋とを有し、該上蓋に上記成長容器の外部に向けて凹んだ種収容部を形成したものを用い、
上記ＳｉＣ種結晶としては、成長方向に２０ｍｍ以上の厚さを有するものを用い、該ＳｉＣ種結晶を、その上記成長面とＳｉＣ原料の発生源とが対向するよう上記種収容部に埋め込み、上記成長面と反対側の裏面を上記上蓋の内表面から上記ＳｉＣ原料の発生源と離れる方向に後退させて配置することを特徴とするＳｉＣ単結晶の製造方法にある（請求項１）。 The present invention provides a method for producing a SiC single crystal by arranging a SiC seed crystal in a growth vessel and growing a bulk SiC single crystal on a growth surface of the SiC seed crystal.
The growth vessel has a main body portion to which SiC raw material is supplied and an upper lid disposed on the main body portion, and uses a seed storage portion that is recessed toward the outside of the growth vessel on the upper lid.
As the SiC seed crystal, one having a thickness of 20 mm or more in the growth direction is used, and the SiC seed crystal is embedded in the seed container so that the growth surface and the source of the SiC raw material face each other. The SiC single crystal manufacturing method is characterized in that the rear surface opposite to the growth surface is disposed so as to recede from the inner surface of the upper lid in a direction away from the source of the SiC raw material.

次に、本発明の作用効果につき説明する。
本発明の製造方法においては、上記ＳｉＣ種結晶として成長方向に２０ｍｍ以上の厚さを有する比較的長尺のものを用いる。そのため、上記ＳｉＣ種結晶の上記成長面を上記成長容器内に露出させたまま、上記ＳｉＣ種結晶を上蓋の上記種収容部に埋め込んだ配置構成を容易かつ確実に実現することができる。 Next, the effects of the present invention will be described.
In the manufacturing method of the present invention, a relatively long one having a thickness of 20 mm or more in the growth direction is used as the SiC seed crystal. Therefore, it is possible to easily and reliably realize an arrangement configuration in which the SiC seed crystal is embedded in the seed accommodating portion of the upper lid while the growth surface of the SiC seed crystal is exposed in the growth vessel.

また、上記の埋め込んだ配置構成の実現により、上記ＳｉＣ種結晶は、その上記成長面と反対側の上記裏面を上記上蓋の内表面から後退させ、上記成長面の露出位置よりも低温となり易い位置に配置することができる。そのため、上記ＳｉＣ種結晶上に成長するＳｉＣ単結晶の熱を上記裏面を介して効率的に放出することができる。それ故、上記ＳｉＣ単結晶の成長中に上記ＳｉＣ種結晶の周囲に成長する多結晶の放熱性よりも、上記ＳｉＣ種結晶上に成長するＳｉＣ単結晶（以下、適宜成長結晶という）の放熱性を高くすることができる。したがって、上記ＳｉＣ単結晶の成長速度の低下を防止することができ、また、上記ＳｉＣ単結晶の先端に発生しうる先細りを防止することができる。
なお、上記ＳｉＣ単結晶の放熱性は、上記種収容部を外部に連通する開口部とした場合に、より一層向上させることができる。 Further, by realizing the embedded arrangement configuration, the SiC seed crystal has a position where the back surface opposite to the growth surface is retreated from the inner surface of the upper lid, and is likely to be at a lower temperature than the exposed position of the growth surface. Can be arranged. Therefore, the heat of the SiC single crystal grown on the SiC seed crystal can be efficiently released through the back surface. Therefore, the heat dissipation of the SiC single crystal grown on the SiC seed crystal (hereinafter referred to as “growth crystal” as appropriate) rather than the heat dissipation of the polycrystalline growing around the SiC seed crystal during the growth of the SiC single crystal. Can be high. Therefore, it is possible to prevent a decrease in the growth rate of the SiC single crystal, and it is possible to prevent tapering that may occur at the tip of the SiC single crystal.
In addition, the heat dissipation of the SiC single crystal can be further improved when the seed accommodating portion is an opening communicating with the outside.

また、本発明の製造方法において、上記ＳｉＣ種結晶は、その上記成長面と反対側の裏面を上記上蓋の内表面から上記ＳｉＣ原料の発生源と離れる方向に後退させて配置する。
そのため、上記ＳｉＣ種結晶の周囲に成長する多結晶が、上記ＳｉＣ種結晶上に成長する成長結晶に悪影響を及ぼして、上記ＳｉＣ単結晶の品質が劣化することを防止することができる。
特に、上記ＳｉＣ種結晶上に繰り返しＳｉＣ単結晶を成長させてＳｉＣ単結晶の長尺化や大口径化を図る場合には、上記ＳｉＣ種結晶上に成長した上記ＳｉＣ単結晶を再び上記ＳｉＣ種結晶として用い、該ＳｉＣ種結晶の上記裏面を上記上蓋の内表面から後退させるように配置して成長させることができる。このとき、上記ＳｉＣ種結晶は、その大部分を上記成長容器の内表面よりも後退させて配置することができるため、周囲にて成長する多結晶の影響をほとんど受けない。そのため、長尺又は大口径のＳｉＣ単結晶を高品質な状態で得ることができる。 Further, in the manufacturing method of the present invention, the SiC seed crystal is disposed with its back surface opposite to the growth surface retracted from the inner surface of the upper lid in a direction away from the SiC source generation source.
Therefore, it is possible to prevent the polycrystals grown around the SiC seed crystal from adversely affecting the grown crystals grown on the SiC seed crystal and deteriorating the quality of the SiC single crystal.
In particular, when a SiC single crystal is repeatedly grown on the SiC seed crystal to increase the length or diameter of the SiC single crystal, the SiC single crystal grown on the SiC seed crystal is again used as the SiC seed crystal. It can be used as a crystal and can be grown by arranging the back surface of the SiC seed crystal so as to recede from the inner surface of the upper lid. At this time, since most of the SiC seed crystal can be disposed so as to recede from the inner surface of the growth vessel, the SiC seed crystal is hardly affected by the polycrystals grown around. Therefore, a long or large diameter SiC single crystal can be obtained in a high quality state.

一般に、長尺化や大口径化を図ると、ＳｉＣ単結晶は放熱性が低下し成長速度が遅くなったり、周囲の多結晶からの悪影響を受けやすく品質が劣化し易くなる。しかし、本発明においては、上記のごとく、上記ＳｉＣ種結晶の上記裏面を上記上蓋の内表面から後退させるように上記ＳｉＣ種結晶を配置しているため、上記ＳｉＣ種結晶及び該ＳｉＣ種結晶上に成長する上記ＳｉＣ単結晶の熱を上記成長容器の外部へ効率的に排出することができ、成長速度の低下を防止できる。それ故、大口径で長尺のＳｉＣ単結晶を短時間で製造できる。   In general, when the length is increased or the diameter of the SiC is increased, the heat dissipation of the SiC single crystal is reduced, the growth rate is slowed down, and the quality is easily deteriorated due to the bad influence from the surrounding polycrystals. However, in the present invention, as described above, since the SiC seed crystal is disposed so that the back surface of the SiC seed crystal is retracted from the inner surface of the upper lid, the SiC seed crystal and the SiC seed crystal are arranged on the SiC seed crystal. Thus, the heat of the SiC single crystal grown on the substrate can be efficiently discharged to the outside of the growth vessel, and the growth rate can be prevented from decreasing. Therefore, a large-diameter and long SiC single crystal can be produced in a short time.

また、本発明の製造方法においては、従来のごとく、上記成長容器内に可動部等の装置を設ける必要がない。そのため、摩擦や振動によって上記成長容器内に塵が発生することがほとんどない。それ故、成長結晶中に異物などが混入することを防止でき、高品質のＳｉＣ単結晶を作製することができる。
以上のごとく、本発明によれば、大口径及び長尺の、高品質なＳｉＣ単結晶を短時間で製造できるＳｉＣ単結晶の製造方法を提供することができる。 Moreover, in the manufacturing method of this invention, it is not necessary to provide apparatuses, such as a movable part, in the said growth container like the past. Therefore, dust is hardly generated in the growth vessel due to friction or vibration. Therefore, it is possible to prevent foreign matters from being mixed into the grown crystal, and a high-quality SiC single crystal can be produced.
As described above, according to the present invention, it is possible to provide a method for producing a SiC single crystal capable of producing a large-diameter and long-sized high-quality SiC single crystal in a short time.

本発明（請求項１）において、上記ＳｉＣ種結晶としては、その成長方向の厚みが２０ｍｍ以上のものを用いる。上記ＳｉＣ種結晶の厚みが２０ｍｍ未満の場合には、上記種収容部に埋め込み、上記裏面を上記上蓋の内表面から後退させて配置することが困難になる。その結果、上述の作用効果が得られなくなるおそれがある。   In the present invention (Invention 1), the SiC seed crystal having a thickness in the growth direction of 20 mm or more is used. When the thickness of the SiC seed crystal is less than 20 mm, it is difficult to dispose the SiC seed crystal in the seed accommodating portion and to place the back surface backward from the inner surface of the upper lid. As a result, the above-described effects may not be obtained.

また、上記成長容器は、その上記上蓋に、上記成長容器の外部に向けて凹んだ上記種収容部を有しており、上記ＳｉＣ種結晶をこの種収容部に埋め込んで配置する。上記ＳｉＣ種結晶の形状は、例えば円柱状、角柱状、及び直方体状等があり、上記上蓋の上記種収容部は、このＳｉＣ種結晶の形状に合わせて形成することができる。   Moreover, the said growth container has the said seed accommodation part recessed toward the exterior of the said growth container in the said upper cover, The said SiC seed crystal is embedded and arrange | positioned in this seed accommodation part. The shape of the SiC seed crystal includes, for example, a cylindrical shape, a prismatic shape, a rectangular parallelepiped shape, and the like, and the seed accommodating portion of the upper lid can be formed according to the shape of the SiC seed crystal.

また、上記成長容器の上記本体部には、上記ＳｉＣ原料が供給される。後述の昇華再析出法によりＳｉＣ単結晶を成長させる場合には、上記ＳｉＣ原料として、例えばＳｉＣ粉末等を供給することができる。また、後述のＣＶＤ法によりＳｉＣ単結晶を成長させる場合には、上記ＳｉＣ原料として、例えばケイ素を含有するケイ素含有ガスと炭素を含有する炭素含有ガスとを供給することができる。ケイ素含有ガスとしては例えばＳｉＨ4等があり、また炭素含有ガスとしては例えばＣ3Ｈ8等がある。 The SiC raw material is supplied to the main body of the growth vessel. When a SiC single crystal is grown by a sublimation reprecipitation method to be described later, for example, SiC powder or the like can be supplied as the SiC raw material. Moreover, when growing a SiC single crystal by the CVD method described later, for example, a silicon-containing gas containing silicon and a carbon-containing gas containing carbon can be supplied as the SiC raw material. Examples of the silicon-containing gas include SiH 4 , and examples of the carbon-containing gas include C 3 H 8 .

上記ＳｉＣ種結晶上にバルク上のＳｉＣ単結晶を成長させる方法としては、例えば昇華再析出法や、ＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）法などを利用することができる。
好ましくは、昇華再析出法がよい。この場合には、充分な成長高さが得られるため、より短時間で、大口径で長尺のＳｉＣ単結晶を得ることができる。 As a method for growing a SiC single crystal in bulk on the SiC seed crystal, for example, a sublimation reprecipitation method, a CVD (Chemical Vapor Deposition) method, or the like can be used.
The sublimation reprecipitation method is preferable. In this case, since a sufficient growth height can be obtained, a large-diameter and long SiC single crystal can be obtained in a shorter time.

また、本発明において、上記ＳｉＣ種結晶としては、本発明の製造方法により作製したＳｉＣ単結晶を用いることができる。即ち、上記ＳｉＣ種結晶の上記成長面上に上記ＳｉＣ単結晶を成長させてＳｉＣ単結晶を作製し、該ＳｉＣ単結晶を上記ＳｉＣ種結晶として再び用いて、その上記成長面上に上記ＳｉＣ単結晶を成長させることができる。このように繰り返してＳｉＣ単結晶を成長させることにより、上記ＳｉＣ単結晶のさらなる大口径化及び長尺化が可能になる。   In the present invention, the SiC single crystal produced by the production method of the present invention can be used as the SiC seed crystal. That is, the SiC single crystal is produced by growing the SiC single crystal on the growth surface of the SiC seed crystal, the SiC single crystal is again used as the SiC seed crystal, and the SiC single crystal is formed on the growth surface. Crystals can be grown. By repeatedly growing the SiC single crystal in this manner, the SiC single crystal can be further increased in diameter and length.

上記ＳｉＣ種結晶としては、例えば昇華再析出法等により成長したＳｉＣ単結晶から切断・成形・研磨して作製された単結晶基板等を用いることができる。
上記ＳｉＣ種結晶において、上記ＳｉＣ単結晶の成長に用いる上記成長面は、化学洗浄等により付着物を除去し、ＲＩＥ（Ｒｅａｃｔｉｖｅ Ｉｏｎ Ｅｔｃｈｉｎｇ）及び犠牲酸化等により切断や研磨に伴う加工変質層を除去しておくことが好ましい。このように、付着物や加工変質層を除去しておくことにより、成長結晶内に上記種結晶から欠陥が継承されるのを防止することができ、高品質のＳｉＣ単結晶を作製することができる。 As the SiC seed crystal, for example, a single crystal substrate produced by cutting, shaping, and polishing from a SiC single crystal grown by a sublimation reprecipitation method or the like can be used.
In the SiC seed crystal, the growth surface used for the growth of the SiC single crystal removes deposits by chemical cleaning or the like, and removes a damaged layer due to cutting or polishing by RIE (Reactive Ion Etching) and sacrificial oxidation. It is preferable to keep it. Thus, by removing the deposits and the work-affected layer, it is possible to prevent defects from being inherited from the seed crystal in the grown crystal, and to produce a high-quality SiC single crystal. it can.

次に、上記ＳｉＣ種結晶の側面部の少なくとも一部には、該側面部を覆う保護材が配設されていることが好ましい（請求項２）。
この場合には、上記成長容器の内側において、該成長容器の内表面から成長する多結晶が上記ＳｉＣ種結晶に悪影響を及ぼして該ＳｉＣ種結晶から成長するＳｉＣ単結晶に転位が発生することを防止できる。また、上記保護材が上記ＳｉＣ種結晶の側面における上記成長容器の外側に位置する部分に配設されている場合には、上記成長容器の外側において、上記ＳｉＣ種結晶からＳｉＣが昇華してしまうことを防止することができる。 Next, it is preferable that a protective material covering the side surface portion is disposed on at least a part of the side surface portion of the SiC seed crystal.
In this case, inside the growth vessel, the polycrystal grown from the inner surface of the growth vessel has an adverse effect on the SiC seed crystal, and dislocation occurs in the SiC single crystal grown from the SiC seed crystal. Can be prevented. Moreover, when the said protective material is arrange | positioned in the part located in the outer side of the said growth container in the side surface of the said SiC seed crystal, SiC will sublime from the said SiC seed crystal in the outer side of the said growth container. This can be prevented.

また、上記保護材は、上記ＳｉＣ種結晶の側面のみならず、上記ＳｉＣ種結晶における上記成長面と反対側の上記裏面に配設することもできる。この場合には、上記ＳｉＣ種結晶の裏面からＳｉＣが昇華してしまうことを防止できる。   Moreover, the said protective material can also be arrange | positioned not only on the side surface of the said SiC seed crystal but on the said back surface on the opposite side to the said growth surface in the said SiC seed crystal. In this case, it is possible to prevent SiC from sublimating from the back surface of the SiC seed crystal.

また、上記保護材としては黒鉛よりなるものを用いることができる。この場合には、上記保護材は、上記ＳｉＣ種結晶上にＳｉＣ単結晶を成長させるときの例えば１８００℃〜２５００℃という高い温度においても安定に存在できる。また、上記保護材としては、例えば黒鉛よりなる板を上記ＳｉＣ種結晶に貼付することにより配設することができる。また、上記保護材としては、黒鉛粉末を分散させたフェノール樹脂等を上記ＳｉＣ種結晶に塗布し焼成して、膜状の黒鉛を形成させることによっても配設することができる。   Moreover, what consists of graphite can be used as said protective material. In this case, the protective material can exist stably even at a high temperature of, for example, 1800 ° C. to 2500 ° C. when the SiC single crystal is grown on the SiC seed crystal. Moreover, as said protective material, it can arrange | position by sticking the board which consists of graphite, for example to the said SiC seed crystal. The protective material can also be disposed by applying a phenol resin or the like in which graphite powder is dispersed to the SiC seed crystal and baking it to form filmy graphite.

また、上記ＳｉＣ種結晶と、上記保護材とは一体的に接合されていることが好ましい（請求項３）。
この場合には、上記ＳｉＣ種結晶と上記保護材との接着性が高まり、上記ＳｉＣ種結晶の放熱性を向上させることができる。また、上記ＳｉＣ種結晶と上記保護材とが一体的に接合されていない場合には、上記ＳｉＣ種結晶と上記保護材との間でＳｉＣの昇華再析出が起き、上記ＳｉＣ種結晶上に成長する上記ＳｉＣ単結晶に欠陥が発生するおそれがある。上記ＳｉＣ種結晶と上記保護材とは、例えば接着剤等を用いて一体的に接合させることができる。
また、上記ＳｉＣ種結晶と上記保護材との間に、後述の応力緩衝材を配設する場合には、上記ＳｉＣ種結晶と上記保護材とを、上記応力緩衝材を介して一体的に接合させることができる。 Further, it is preferable that the SiC seed crystal and the protective material are integrally joined.
In this case, the adhesion between the SiC seed crystal and the protective material is enhanced, and the heat dissipation of the SiC seed crystal can be improved. Further, when the SiC seed crystal and the protective material are not integrally joined, SiC sublimation reprecipitation occurs between the SiC seed crystal and the protective material, and grows on the SiC seed crystal. There is a risk of defects occurring in the SiC single crystal. The SiC seed crystal and the protective material can be integrally joined using, for example, an adhesive.
In addition, when a stress buffer material described later is disposed between the SiC seed crystal and the protective material, the SiC seed crystal and the protective material are integrally bonded via the stress buffer material. Can be made.

また、上記保護材と上記ＳｉＣ種結晶との間には、両者の間にはたらく熱応力を緩和するための応力緩衝材が配設されていることが好ましい（請求項４）。
また、上記保護材と上記上蓋との間には、両者の間に働く熱応力を緩和するための応力緩衝材が配設されていることが好ましい（請求項５）。
この場合には、上記ＳｉＣ種結晶と上記保護材との熱膨張差や、上記保護材と上記成長容器の上蓋との熱膨張差に起因した応力を緩衝することができる。即ち、上記応力緩衝材は、熱膨張差に起因した応力を歪みとして吸収することができる。そのため、上記ＳｉＣ種結晶に応力がほとんどかからない状態でＳｉＣ単結晶を成長させることができ、格子面の反りやマクロ欠陥の発生を防止することができる。このような応力緩衝材としては、例えば一定の柔軟性を有するものを用いることができる。具体的には、後述するごとく、例えば一定の引張強度又は／及びヤング率を有するものを用いることができる。 Moreover, it is preferable that a stress buffering material for relaxing thermal stress acting between the protective material and the SiC seed crystal is disposed between the protective material and the SiC seed crystal.
Further, it is preferable that a stress buffer material for relaxing thermal stress acting between the protective material and the upper lid is disposed between the protective material and the upper lid.
In this case, it is possible to buffer the stress caused by the difference in thermal expansion between the SiC seed crystal and the protective material and the difference in thermal expansion between the protective material and the upper lid of the growth vessel. That is, the stress buffer material can absorb the stress caused by the difference in thermal expansion as strain. Therefore, a SiC single crystal can be grown in a state where stress is hardly applied to the SiC seed crystal, and lattice warpage and macro defects can be prevented. As such a stress buffer material, for example, a material having a certain flexibility can be used. Specifically, as described later, for example, a material having a certain tensile strength and / or Young's modulus can be used.

上記応力緩衝材は、その引張強度が１０ＭＰａ以下であることが好ましい。上記応力緩衝材の引張強度が１０ＭＰａを越える場合には、上記応力緩衝材と、上記ＳｉＣ種結晶や上記保護材との間の熱膨張差に起因して応力が発生し、この応力が成長中のＳｉＣ単結晶に加えられることにより、得られるＳｉＣ単結晶の品質が劣化するおそれがある。
また、上記応力緩衝材は、そのヤング率が５ＧＰａ以下であることが好ましい。上記応力緩衝材のヤング率が５ＧＰａを越える場合には、上記応力緩衝材と、上記ＳｉＣ種結晶や上記保護材との間の熱膨張差に起因して発生する応力により、得られるＳｉＣ単結晶の品質が劣化するおそれがある。 The stress buffer material preferably has a tensile strength of 10 MPa or less. When the tensile strength of the stress buffer material exceeds 10 MPa, stress is generated due to a difference in thermal expansion between the stress buffer material and the SiC seed crystal or the protective material. When added to the SiC single crystal, the quality of the obtained SiC single crystal may be deteriorated.
The stress buffer material preferably has a Young's modulus of 5 GPa or less. When the Young's modulus of the stress buffer material exceeds 5 GPa, the SiC single crystal obtained by the stress generated due to the difference in thermal expansion between the stress buffer material and the SiC seed crystal or the protective material The quality of the product may deteriorate.

また、上記応力緩衝材としては、柔軟性黒鉛シートを用いることができる。柔軟性黒鉛シートは、該柔軟性黒鉛シートを構成している結晶粒子のｃ軸が厚さ方向に配向しているため、１〜１０ＭＰａという低い引張強度を示すことができる。そのため、この場合には、上記ＳｉＣ種結晶と上記保護材との間、又は上記保護材と上記上蓋との間に生じる熱応力を充分に緩衝することができる。
また、上記柔軟性黒鉛シートは、上記ＳｉＣ単結晶を成長させる際の例えば１８００℃〜２５００℃という高い温度においても安定に存在できるため、上記応力緩衝材として適している。 Moreover, a flexible graphite sheet can be used as the stress buffer material. The flexible graphite sheet can exhibit a tensile strength as low as 1 to 10 MPa because the c-axis of the crystal particles constituting the flexible graphite sheet is oriented in the thickness direction. Therefore, in this case, the thermal stress generated between the SiC seed crystal and the protective material or between the protective material and the upper lid can be sufficiently buffered.
Further, the flexible graphite sheet is suitable as the stress buffer because it can exist stably even at a high temperature of, for example, 1800 ° C. to 2500 ° C. when the SiC single crystal is grown.

また、上記応力緩衝材は、その厚みが０．０１〜３．０ｍｍであることが好ましい。応力緩衝材の厚みが０．０１ｍｍ未満の場合には、上記ＳｉＣ種結晶と上記保護材との間、又は上記保護材と上記上蓋との間の熱膨張差に起因する応力を充分に緩衝することができないおそれがある。一方、３．０ｍｍ越える場合には、上記ＳｉＣ種結晶の冷却効率が悪くなり、成長速度が遅くなるおそれがある。   Moreover, it is preferable that the thickness of the said stress buffer material is 0.01-3.0 mm. When the thickness of the stress buffer material is less than 0.01 mm, the stress due to the difference in thermal expansion between the SiC seed crystal and the protective material or between the protective material and the upper lid is sufficiently buffered. There is a risk that it will not be possible. On the other hand, if it exceeds 3.0 mm, the cooling efficiency of the SiC seed crystal is deteriorated, and the growth rate may be slow.

また、上記ＳｉＣ種結晶として、ｃ面よりオフセット角度６０°以内の面を上記成長面として露出させたものを用いることが好ましい（請求項６）
この場合には、上記ＳｉＣ種結晶は、略ｃ軸方向（＜０００１＞方向）に成長し、所謂ｃ面成長を行うことができる。そして、このようにｃ面成長をおこなうことにより、積層欠陥の少ないＳｉＣ単結晶を作製することができる。 Further, it is preferable to use a SiC seed crystal in which a surface within an offset angle of 60 ° from the c-plane is exposed as the growth surface.
In this case, the SiC seed crystal grows substantially in the c-axis direction (<0001> direction) and can perform so-called c-plane growth. And by performing c-plane growth in this way, a SiC single crystal with few stacking faults can be produced.

また、上記ＳｉＣ種結晶として、ｃ面と略垂直な面を上記成長面として露出させたものを用いることが好ましい（請求項７）。
この場合には、上記ＳｉＣ種結晶はｃ軸と略垂直な方向に成長し、所謂ａ面成長を行うことができる。そして、このようにａ面成長をおこなうことにより、マイクロパイプ欠陥や螺旋転位の少ないＳｉＣ単結晶を作製することができる。また、本発明においては、上記のごとく、上記ＳｉＣ種結晶を上記種収容部に埋め込んで配置するため、この場合には、略＜１−１００＞軸又は略＜１１−２０＞軸方向に長尺なＳｉＣ単結晶を作製することができる。また、このようなＳｉＣ単結晶は、そのｃ面側から見るとｃ面が大口径化したものとなる。 Further, it is preferable to use a SiC seed crystal in which a plane substantially perpendicular to the c-plane is exposed as the growth plane.
In this case, the SiC seed crystal grows in a direction substantially perpendicular to the c-axis and can perform so-called a-plane growth. And by performing a-plane growth in this way, a SiC single crystal with few micropipe defects and screw dislocations can be produced. Further, in the present invention, as described above, the SiC seed crystal is embedded in the seed accommodating portion, and in this case, the SiC seed crystal is long in the direction of about <1-100> axis or about <11-20> axis. A long SiC single crystal can be produced. In addition, such a SiC single crystal has a larger c-plane diameter when viewed from the c-plane side.

具体的には、図２２に示すごとく、ＳｉＣ単結晶は、その主要な面方位として｛０００１｝面（ｃ面）と、｛０００１｝面に垂直な｛１−１００｝面（ａ面）及び｛１１−２０｝面（ａ面）とを有している。そして、一般的には、ＳｉＣ種結晶上にＳｉＣ単結晶を成長させる際には、｛０００１｝面（ｃ面）又は｛０００１｝面からオフセット角度１０°以内の面を種結晶の成長面として露出するＳｉＣ種結晶を用いてＳｉＣ単結晶を成長させるという、所謂ｃ面成長が行われる。ところが、このようなｃ面成長を行って得られる成長結晶（ｃ面成長結晶）中には、＜０００１＞方向と略平行な方向にマイクロパイプ欠陥や螺旋転位等の欠陥が非常に多く発生する。
上記のごとく、上記ＳｉＣ種結晶をｃ軸（＜０００１＞方向）と略垂直な方向に成長させるという、所謂ａ面成長を行うことにより、マイクロパイプ欠陥や螺旋転位が少なく、略＜１−１００＞軸又は略＜１１−２０＞軸方向に長尺なＳｉＣ単結晶が得られる。このようなＳｉＣ単結晶は、上記のごとく、そのｃ面側から見るとｃ面が大口径化したものとなる。 Specifically, as shown in FIG. 22, the SiC single crystal has a {0001} plane (c plane) as a main plane orientation, a {1-100} plane (a plane) perpendicular to the {0001} plane, and And {11-20} plane (a-plane). In general, when a SiC single crystal is grown on a SiC seed crystal, the {0001} plane (c plane) or a plane within an offset angle of 10 ° from the {0001} plane is used as the seed crystal growth plane. So-called c-plane growth is performed in which a SiC single crystal is grown using the exposed SiC seed crystal. However, in a growth crystal (c-plane growth crystal) obtained by performing such c-plane growth, a very large number of defects such as micropipe defects and screw dislocations are generated in a direction substantially parallel to the <0001> direction. .
As described above, by performing so-called a-plane growth in which the SiC seed crystal is grown in a direction substantially perpendicular to the c-axis (<0001> direction), there are few micropipe defects and screw dislocations, and approximately <1-100. A SiC single crystal elongated in the> axis or substantially <11-20> axis direction is obtained. As described above, such a SiC single crystal has a larger c-plane diameter when viewed from the c-plane side.

また、上記ａ面成長を繰り返しおこなうことにより、ＳｉＣ単結晶中の欠陥や転位を一層低減させることができる。また、上記ａ面成長を繰り返し行うことにより、ｃ面（｛０００１｝面）をさらに大口径化させることができる。即ち、上記ＳｉＣ種結晶を略＜１−１００＞方向（又は略＜１１−２０＞方向）に成長させてＳｉＣ単結晶を作製し、該ＳｉＣ単結晶を種結晶として用いて、略＜１１−２０＞方向（又は略＜１−１００＞方向）に成長させることにより、｛０００１｝面（ｃ面）の大口径化を図ることができる。   Further, by repeating the a-plane growth, defects and dislocations in the SiC single crystal can be further reduced. Further, by repeatedly performing the a-plane growth, the c-plane ({0001} plane) can be further enlarged. That is, the SiC seed crystal is grown in a substantially <1-100> direction (or a substantially <11-20> direction) to produce a SiC single crystal, and the SiC single crystal is used as a seed crystal. By growing in the 20> direction (or substantially <1-100> direction), the {0001} plane (c plane) can be increased in diameter.

また、上記のごとく、ｃ面と略垂直な面を上記成長面として露出させたＳｉＣ種結晶を成長させて得られるＳｉＣ単結晶、即ちａ面成長を行って得られるＳｉＣ単結晶から、｛０００１｝面又は｛０００１｝面からオフセット角度６０℃以内の面を成長面として露出させたＳｉＣ種結晶を作製し、該ＳｉＣ種結晶上にさらにＳｉＣ単結晶を成長させることが好ましい。
この場合には、大口径化したｃ面を有し、かつ螺旋転位、マイクロパイプ欠陥、及び積層欠陥の少ない高品質のＳｉＣ単結晶を得ることができる。
即ち、ａ面成長においては、上記のごとく螺旋転位やマイクロパイプ欠陥を低減させることができるが、＜１−１００＞方向（又は＜１１−２０＞方向）と略平行な向きに積層欠陥が発生する。上記のごとく、ａ面成長を行って螺旋転位やマイクロパイプ欠陥を低減させた後に、ｃ面成長（略＜０００１＞方向への成長）を行うことにより、螺旋転位及びマイクロパイプ欠陥がほとんどなく、さらに積層欠陥もほとんどない高品質なＳｉＣ単結晶を得ることができる。積層欠陥は、略＜０００１＞方向への成長にはほとんど発生しないからである。 Further, as described above, from a SiC single crystal obtained by growing a SiC seed crystal having a plane substantially perpendicular to the c-plane exposed as the growth plane, that is, a SiC single crystal obtained by performing a-plane growth, {0001 } Surface or {0001} surface, it is preferable to produce a SiC seed crystal with a surface within an offset angle of 60 ° C. exposed as a growth surface, and to further grow a SiC single crystal on the SiC seed crystal.
In this case, a high-quality SiC single crystal having a large-diameter c-plane and having few screw dislocations, micropipe defects, and stacking faults can be obtained.
That is, in the a-plane growth, the screw dislocations and micropipe defects can be reduced as described above, but stacking faults are generated in a direction substantially parallel to the <1-100> direction (or <11-20> direction). To do. As described above, after performing a-plane growth to reduce screw dislocations and micropipe defects, by performing c-plane growth (growth in a substantially <0001> direction), there are almost no screw dislocations and micropipe defects. Furthermore, a high-quality SiC single crystal having almost no stacking faults can be obtained. This is because the stacking fault hardly occurs in the growth in the substantially <0001> direction.

なお、本明細書、特許請求の範囲、及び図面において、｛０００１｝、｛１−１００｝、及び｛１１−２０｝は、所謂結晶面の面指数を表している。上記面指数において、「−」記号は通常数字の上に付されるが、本明細書及び図面においては、書類作成の便宜のため数字の左側に付した。また、＜０００１＞、＜１−１００＞、及び＜１１−２０＞は、結晶内の方向を表し、「−」記号の取り扱いについては、上記面指数と同様である。   In the present specification, claims, and drawings, {0001}, {1-100}, and {11-20} represent plane indices of so-called crystal planes. In the above surface index, the “-” symbol is usually added on the number, but in the present specification and drawings, it is added on the left side of the number for the convenience of document preparation. Further, <0001>, <1-100>, and <11-20> represent directions in the crystal, and the handling of the “−” symbol is the same as the above-described plane index.

次に、上記ＳｉＣ種結晶は、螺旋転位密度が１００個／ｃｍ2以上の領域を少なくとも一部に有することが好ましい（請求項８）。
この場合には、螺旋転位密度が１００個／ｃｍ2以上の領域を有する上記ＳｉＣ種結晶を、ｃ軸方向（＜０００１＞方向）と略垂直な方向に成長させることにより、螺旋転位密度が１００個／ｃｍ2以上の領域と螺旋転位密度が１００個／ｃｍ2未満の領域とを有するＳｉＣ単結晶を作製することができる。螺旋転位はｃ軸方向と略垂直な方向にはほとんど継承されないからである。そして、このＳｉＣ単結晶から螺旋転位密度が１００個／ｃｍ2以上の領域と、螺旋転位密度が１００個／ｃｍ2未満の領域とを含み、かつｃ面からオフセット角度６０°以内の面が露出するように新たにＳｉＣ種結晶を切り出すことにより、後述の転位制御種結晶を作製することができる。また、本発明においては、上記のごとく、上記ＳｉＣ種結晶を上記成長容器の上記種収容部に埋め込み、成長容器の内表面から後退させて配置するため、上記のごとく、ｃ軸方向（＜０００１＞方向）と略垂直な方向に成長させることにより、＜０００１＞方向と略垂直な方向に長尺なＳｉＣ単結晶を得ることができる。したがって、該ＳｉＣ単結晶から切り出して得られる上記転位制御種結晶を大口径のものにすることができる。 Then, the SiC seed crystal, screw dislocation density is preferably has at least in part 100 / cm 2 or more regions (claim 8).
In this case, by growing the SiC seed crystal having a region with a screw dislocation density of 100 / cm 2 or more in a direction substantially perpendicular to the c-axis direction (<0001> direction), the screw dislocation density is 100. A SiC single crystal having a region of at least pieces / cm 2 and a region having a screw dislocation density of less than 100 pieces / cm 2 can be produced. This is because the screw dislocation is hardly inherited in the direction substantially perpendicular to the c-axis direction. The SiC single crystal includes a region having a screw dislocation density of 100 / cm 2 or more and a region having a screw dislocation density of less than 100 / cm 2 , and a surface within an offset angle of 60 ° from the c-plane is exposed. As described above, a dislocation control seed crystal described later can be produced by newly cutting a SiC seed crystal. Further, in the present invention, as described above, the SiC seed crystal is embedded in the seed container of the growth vessel and is disposed so as to recede from the inner surface of the growth vessel. Therefore, as described above, the c-axis direction (<0001 > Direction), a long SiC single crystal can be obtained in a direction substantially perpendicular to the <0001> direction. Therefore, the dislocation control seed crystal obtained by cutting from the SiC single crystal can have a large diameter.

以下、上記転位制御種結晶について説明する。
上記転位制御種結晶は、｛０００１｝面よりオフセット角度６０°以内の面を成長面として有し、成長中のＳｉＣ単結晶に螺旋転位を螺旋転位密度１００個／ｃｍ2以上で発生することができる螺旋転位発生可能領域を、上記成長面上の５０％以下の領域に有すると共に、上記成長面上における上記螺旋転位発生可能領域以外の領域には、上記成長面上に露出している螺旋転位が螺旋転位密度１００個／ｃｍ2未満である低密度螺旋転位領域を有する。
そして、該転位制御種結晶の上記成長面上にＳｉＣ単結晶を成長させるときにおいては、該ＳｉＣ単結晶の成長途中の表面である途中表面に、平坦なｃ面ファセットが形成され、かつ該ｃ面ファセットと、上記成長面上の上記螺旋転位発生可能領域をｃ軸方向又は上記成長面に垂直な方向において上記途中表面に投影した領域とが、少なくとも一部で重なるようにＳｉＣ単結晶を成長させることが好ましい（請求項９）。 Hereinafter, the dislocation control seed crystal will be described.
The dislocation control seed crystal has a plane with an offset angle of 60 ° or less from the {0001} plane as a growth plane, and screw dislocations are generated in the growing SiC single crystal at a screw dislocation density of 100 pieces / cm 2 or more. A region having a screw dislocation generation potential that can be generated in a region of 50% or less on the growth surface, and a region other than the region capable of generating the screw dislocation on the growth surface is exposed on the growth surface. Has a low density screw dislocation region having a screw dislocation density of less than 100 / cm 2 .
Then, when the SiC single crystal is grown on the growth surface of the dislocation control seed crystal, a flat c-plane facet is formed on the intermediate surface, which is the surface during the growth of the SiC single crystal, and the c The SiC single crystal is grown so that the surface facet and the region in which the screw dislocation generation region on the growth surface is projected onto the intermediate surface in the c-axis direction or the direction perpendicular to the growth surface overlap at least partially. (Claim 9).

このように上記転位制御種結晶上にＳｉＣ単結晶を成長させた場合には、上記螺旋転位発生可能領域から成長中のＳｉＣ単結晶中に螺旋転位が発生すると共に、その少なくとも一部が成長中のＳｉＣ単結晶の上記ｃ面ファセット内に位置するように、上記ＳｉＣ単結晶が成長する。その結果、上記ＳｉＣ単結晶中に異種多形結晶や異方位結晶が形成されることを防止することができる。また、成長中にランダムに螺旋転位が発生することを防止することができる。それ故、上記ＳｉＣ単結晶の品質をさらに向上させることができる。   When the SiC single crystal is grown on the dislocation control seed crystal as described above, the screw dislocation is generated in the growing SiC single crystal from the region where the screw dislocation can be generated, and at least a part of the crystal is growing. The SiC single crystal grows so as to be located in the c-plane facet of the SiC single crystal. As a result, it is possible to prevent the formation of different polymorphic crystals or differently oriented crystals in the SiC single crystal. Further, it is possible to prevent the occurrence of random screw dislocations during the growth. Therefore, the quality of the SiC single crystal can be further improved.

上記螺旋転位発生可能領域は、螺旋転位を螺旋転位密度１００個／ｃｍ2以上で発生できる領域である。
上記螺旋転位発生領域から発生する螺旋転位が１００個／ｃｍ2未満の場合には、成長中のＳｉＣ単結晶に異種多形や異方位結晶が形成されるおそれがある。
また、上記螺旋転位発生可能領域は、上記転位制御種結晶における上記成長面上の５０％以下の領域にある。上記螺旋転位発生可能領域が５０％を越える場合には、成長後に得られる上記ＳｉＣ単結晶中に多くの螺旋転位が形成され、ＳｉＣ単結晶の品質が劣化するおそれがある。好ましくは、上記螺旋転位発生可能領域は、上記成長面上の３０％以下であることがよい。より好ましくは、１０％以下である。 The region capable of generating screw dislocations is a region in which screw dislocations can be generated at a screw dislocation density of 100 / cm 2 or more.
When screw dislocations generated from the screw dislocation generation region is less than 100 / cm 2, there is a possibility that different polymorphs or differently oriented crystal is formed SiC growing single crystal.
Further, the region capable of generating the screw dislocation is in a region of 50% or less on the growth surface in the dislocation control seed crystal. When the region where the screw dislocation can be generated exceeds 50%, many screw dislocations are formed in the SiC single crystal obtained after growth, and the quality of the SiC single crystal may be deteriorated. Preferably, the region where the screw dislocation can be generated is 30% or less on the growth surface. More preferably, it is 10% or less.

また、上記螺旋転位発生可能領域は、上記転位制御種結晶の端部に形成されていることが好ましい。
この場合には、上記螺旋転位発生可能領域から成長中のＳｉＣ単結晶中に発生する螺旋転位の位置を、上記ＳｉＣ単結晶の端部にすることができる。そして、この場合には、上記ＳｉＣ単結晶において、螺旋転位が発生したＳｉＣ単結晶の端部を切除することにより、螺旋転位がほとんどないＳｉＣ単結晶を作製することができる。
なお、螺旋転位が発生した部分は切除せずに、成長後の上記ＳｉＣ単結晶をそのままＳｉＣ半導体等に用いることもできる。 Further, the region capable of generating the screw dislocation is preferably formed at an end portion of the dislocation control seed crystal.
In this case, the position of the screw dislocation generated in the growing SiC single crystal from the region capable of generating the screw dislocation can be the end of the SiC single crystal. In this case, in the SiC single crystal, an SiC single crystal having almost no screw dislocations can be produced by cutting off the end of the SiC single crystal in which the screw dislocations are generated.
The grown SiC single crystal can be used as it is for a SiC semiconductor or the like without cutting away the portion where the screw dislocation has occurred.

また、上記転位制御種結晶は、上記成長面上に露出している螺旋転位が螺旋転位密度１００個／ｃｍ2未満である低密度螺旋転位領域を有している。
上記低密度螺旋転位領域の螺旋転位密度が１００個／ｃｍ2を越える場合には、成長後に得られる上記ＳｉＣ単結晶中に、多くの螺旋転位が形成され、上記ＳｉＣ単結晶の品質が低下するおそれがある。好ましくは、上記低密度螺旋転位領域は、螺旋転位密度が１０個／ｃｍ2未満であることがよい。より好ましくは１個／ｃｍ2未満がよい。最も好ましくは０個／ｃｍ2がよい。 Further, the dislocation control seed crystal, screw dislocations exposed on the growth surface has a low density screw dislocation region is less than screw dislocation density of 100 / cm 2.
When the screw dislocation density in the low density screw dislocation region exceeds 100 / cm 2 , many screw dislocations are formed in the SiC single crystal obtained after growth, and the quality of the SiC single crystal is deteriorated. There is a fear. Preferably, the low-density screw dislocation regions, screw dislocation density may be preferably less than 10 / cm 2. More preferably, it is less than 1 piece / cm 2 . Most preferably, 0 piece / cm 2 is good.

また、上記転位制御種結晶の上記成長面は、｛０００１｝面よりオフセット角度６０°以内の面である。６０°を越える場合には、上記ＳｉＣ単結晶の上記途中表面に、ｃ面ファセットが形成されないおそれがある。また、上記ＳｉＣ単結晶に積層欠陥が発生し、ＳｉＣ単結晶の品質が低下するおそれがある。   The growth surface of the dislocation control seed crystal is a surface having an offset angle of 60 ° or less from the {0001} plane. If it exceeds 60 °, c-plane facets may not be formed on the intermediate surface of the SiC single crystal. In addition, stacking faults may occur in the SiC single crystal, and the quality of the SiC single crystal may be reduced.

また、上記螺旋転位発生可能領域は、例えばＳｉＣ種結晶の成長面上に、機械加工、研削加工、及びイオン注入処理等の表面処理を施し、その結晶構造に部分的に乱れを生じさせることにより形成することもできる。   In addition, the above-described region where the screw dislocation can be generated is, for example, by subjecting the growth surface of the SiC seed crystal to surface treatment such as machining, grinding, and ion implantation to partially disturb the crystal structure. It can also be formed.

次に、上記ＳｉＣ種結晶上に成長したＳｉＣ単結晶を、上記ＳｉＣ種結晶の上記成長面と略平行な方向に切断して取り外し、該ＳｉＣ種結晶上に再びＳｉＣ単結晶を成長させることが好ましい（請求項１０）
この場合には、上記ＳｉＣ種結晶から連続的に高品質なＳｉＣ単結晶を得ることができる。
一般に、ＳｉＣの単結晶成長においては、成長中に成長結晶（ＳｉＣ単結晶）に異種多形が混入し、成長結晶の品質を著しく劣化させるおそれがある。そのため、種結晶上に成長した成長結晶をスライスして新たに種結晶を作製すると、該種結晶中に、成長結晶に混入した異種多結晶が含まれ種結晶として用いることができないおそれがある。
そこで、上記のごとく、上記ＳｉＣ種結晶上に成長したＳｉＣ単結晶を、上記ＳｉＣ種結晶の上記成長面と略平行な方向に切断して取り外し、該ＳｉＣ種結晶上に再びＳｉＣ単結晶を成長させると、たとえ成長中に異種多結晶が発生したとしても、成長したＳｉＣ単結晶は取り外されるため、繰り返しＳｉＣ単結晶の成長を行うことができる。即ち、上記ＳｉＣ種結晶を繰り返し使い回すことが可能になる。 Next, the SiC single crystal grown on the SiC seed crystal is cut and removed in a direction substantially parallel to the growth surface of the SiC seed crystal, and the SiC single crystal is grown again on the SiC seed crystal. Preferred (Claim 10)
In this case, a high-quality SiC single crystal can be obtained continuously from the SiC seed crystal.
In general, in SiC single crystal growth, different types of polymorphs may be mixed into the growth crystal (SiC single crystal) during growth, and the quality of the growth crystal may be significantly degraded. For this reason, when a seed crystal is newly produced by slicing the grown crystal grown on the seed crystal, the seed crystal may contain a heterogeneous polycrystal mixed in the grown crystal and cannot be used as the seed crystal.
Therefore, as described above, the SiC single crystal grown on the SiC seed crystal is cut and removed in a direction substantially parallel to the growth surface of the SiC seed crystal, and the SiC single crystal is grown again on the SiC seed crystal. Then, even if different types of polycrystals are generated during the growth, the grown SiC single crystal is removed, so that the SiC single crystal can be repeatedly grown. That is, the SiC seed crystal can be used repeatedly.

また、一般に厚みが１ｍｍ程度の薄い種結晶を、成長容器の台座に保持して成長させる場合においては、種結晶は台座の熱応力を受けて品質が劣化するため、これを種結晶として繰り返し使い回すことは困難である。しかし、本発明においては、上記のごとく、２０ｍｍ以上の厚さを有するＳｉＣ種結晶を、上記種収容部に埋め込み、上記ＳｉＣ原料の発生源と離れる方向に後退させて配置して成長を行っている。そのため、台座の熱応力をほとんど受けることはなく、ＳｉＣ種結晶の品質はほとんど劣化しないため、上記のごとくＳｉＣ種結晶を使い回すことができる。   In general, when a thin seed crystal having a thickness of about 1 mm is grown on a growth vessel pedestal, the quality of the seed crystal deteriorates due to the thermal stress of the pedestal. Therefore, this seed crystal is repeatedly used as a seed crystal. It is difficult to turn. However, in the present invention, as described above, the SiC seed crystal having a thickness of 20 mm or more is embedded in the seed accommodating portion, and is retracted and disposed in a direction away from the source of the SiC raw material. Yes. Therefore, the thermal stress of the pedestal is hardly received, and the quality of the SiC seed crystal is hardly deteriorated. Therefore, the SiC seed crystal can be reused as described above.

また、上記ＳｉＣ種結晶上に成長した上記ＳｉＣ単結晶には、そのＳｉＣ種結晶側に、上記ＳｉＣ種結晶から継承されたｃ面に平行な積層欠陥が含まれる場合がある。
したがって、上記ＳｉＣ種結晶から継承されたｃ面に平行な積層欠陥を完全に排出するため、上記ＳｉＣ種結晶上に成長した上記ＳｉＣ単結晶のうち、積層欠陥を含まない高品質な部分のみを取り外し、積層欠陥が含まれる部分をＳｉＣ種結晶側に残して新たなＳｉＣ種結晶として用いることが好ましい。即ち、上記ＳｉＣ種結晶上に成長した上記ＳｉＣ単結晶を取り外す際に、積層欠陥が含まれる成長高さ以上でＳｉＣ単結晶を取り外し、積層欠陥が含まれる成長高さ以下の部分をＳｉＣ種結晶に残し、該種結晶を再びＳｉＣ種結晶として利用することが好ましい。この場合には、再度成長を行って得られるＳｉＣ単結晶は全領域において積層欠陥を含まない高品質なものとなり、歩留まりが向上する。なお、上記の成長高さは、上記ＳｉＣ単結晶における上記ＳｉＣ種結晶の成長面からの高さである。 Further, the SiC single crystal grown on the SiC seed crystal may include a stacking fault parallel to the c-plane inherited from the SiC seed crystal on the SiC seed crystal side.
Therefore, in order to completely discharge the stacking faults parallel to the c-plane inherited from the SiC seed crystal, only the high-quality portion that does not include the stacking fault is included in the SiC single crystal grown on the SiC seed crystal. It is preferable to remove and use a new SiC seed crystal, leaving a portion including stacking faults on the SiC seed crystal side. That is, when removing the SiC single crystal grown on the SiC seed crystal, the SiC single crystal is removed at a growth height that includes a stacking fault or higher, and a portion that is less than the growth height that includes a stacking fault is removed from the SiC seed crystal. It is preferable to use the seed crystal again as the SiC seed crystal. In this case, the SiC single crystal obtained by performing the growth again has a high quality that does not include stacking faults in the entire region, and the yield is improved. The growth height is a height from the growth surface of the SiC seed crystal in the SiC single crystal.

（実施例１）
次に、本発明の実施例につき、図１〜図６を用いて説明する。
本例は、成長容器内に２０ｍｍ以上の厚さを有するＳｉＣ種結晶を配置し、該ＳｉＣ種結晶の成長面上にバルク状のＳｉＣ単結晶を成長させてＳｉＣ単結晶を製造する例である。 Example 1
Next, an embodiment of the present invention will be described with reference to FIGS.
In this example, an SiC seed crystal having a thickness of 20 mm or more is disposed in a growth vessel, and a bulk SiC single crystal is grown on the growth surface of the SiC seed crystal to produce an SiC single crystal. .

まず、以下のようにして、厚さ２０ｍｍ以上のＳｉＣ種結晶を準備する。具体的には、ｃ面を成長面として露出する種結晶を準備し、該種結晶を成長させた後、２０ｍｍ以上厚みで切り出してＳｉＣ種結晶を作製する。
種結晶の成長には、図１に示すごとく、成長容器２として、ＳｉＣ原料粉末２３が供給される本体部２１と、該本体部２１から取り外し可能な上蓋２２とを有する坩堝を用いた。本体部２１は、ＳｉＣ原料粉末２３や、種結晶、ＳｉＣ単結晶等を出し入れするために、その上部を開口させてあり、上蓋２２はこの開口部分を塞ぐように配置される。また、上蓋２２は、周囲よりも突出した台座２２５を有しており、種結晶はこの台座２２５に配置される。 First, an SiC seed crystal having a thickness of 20 mm or more is prepared as follows. Specifically, a seed crystal that exposes the c-plane as a growth surface is prepared, and after the seed crystal is grown, it is cut out with a thickness of 20 mm or more to produce a SiC seed crystal.
For the growth of the seed crystal, as shown in FIG. 1, a crucible having a main body portion 21 to which the SiC raw material powder 23 was supplied and an upper lid 22 removable from the main body portion 21 was used as the growth container 2. The main body 21 has an upper portion opened to take in and out the SiC raw material powder 23, seed crystal, SiC single crystal and the like, and the upper lid 22 is disposed so as to close the opening. The upper lid 22 has a pedestal 225 that protrudes from the periphery, and the seed crystal is disposed on the pedestal 225.

まず、本体部内の底部にＳｉＣ原料粉末２３を配置した。また、種結晶１を上蓋２２の台座２２５に接着剤により固定し、この上蓋２２を本体部２３の開口部分に配置した。このとき、ＳｉＣ原料粉末２３と種結晶１の成長面１５とが対向するように、成長面１５の反対側の面と台座２２５とを接着剤により固定した。種結晶１の厚みは、１ｍｍである。
次いで、成長容器２を減圧不活性雰囲気中で温度２１００〜２４００℃に加熱した。このとき、ＳｉＣ原料粉末２３側の温度を種結晶１側の温度よりも２０〜２００℃高く設定した。これにより、図２に示すごとく、成長容器２内のＳｉＣ原料粉末２３が加熱により昇華し、このＳｉＣ原料粉末２３よりも低温の種結晶１上にＳｉＣが堆積し、ＳｉＣ単結晶１０を得た（昇華再析出法）。 First, the SiC raw material powder 23 was arrange | positioned at the bottom part in a main-body part. The seed crystal 1 was fixed to the base 225 of the upper lid 22 with an adhesive, and the upper lid 22 was disposed in the opening portion of the main body 23. At this time, the surface opposite to the growth surface 15 and the base 225 were fixed with an adhesive so that the SiC raw material powder 23 and the growth surface 15 of the seed crystal 1 face each other. The thickness of the seed crystal 1 is 1 mm.
Next, the growth vessel 2 was heated to a temperature of 2100 to 2400 ° C. in a vacuum inert atmosphere. At this time, the temperature on the SiC raw material powder 23 side was set 20 to 200 ° C. higher than the temperature on the seed crystal 1 side. As a result, as shown in FIG. 2, SiC raw material powder 23 in growth vessel 2 is sublimated by heating, and SiC is deposited on seed crystal 1 at a temperature lower than that of SiC raw material powder 23 to obtain SiC single crystal 10. (Sublimation reprecipitation method).

次いで、このＳｉＣ単結晶１０を立方体状に成形し、図３に示すごとく、ｃ面を成長面３５として露出させてＳｉＣ種結晶３を作製した。その厚みは３０ｍｍであった。   Next, the SiC single crystal 10 was formed into a cubic shape, and as shown in FIG. 3, the c-plane was exposed as a growth surface 35 to produce a SiC seed crystal 3. Its thickness was 30 mm.

続いて、図３及び図４に示すような成長容器４を用いて、上記ＳｉＣ種結晶３を成長させる。
同図に示すごとく、成長容器４は、ＳｉＣ原料粉末４３が供給される本体部４１と上蓋４２とからなる坩堝である。上蓋４２は、本体部４１から取り外し可能になっており、本体部４１の上部の開口部分を塞ぐ上蓋の役割を果たしている。また、上蓋４２は、その略中央に、成長容器４の外部に向けて凹んだ種収容部４２５としての開口部を有しており、ＳｉＣ種結晶は、この開口部４２５に配置される。 Subsequently, the SiC seed crystal 3 is grown using a growth vessel 4 as shown in FIGS.
As shown in the figure, the growth vessel 4 is a crucible including a main body 41 and an upper lid 42 to which SiC raw material powder 43 is supplied. The upper lid 42 is detachable from the main body 41 and serves as an upper lid that closes the upper opening of the main body 41. Further, the upper lid 42 has an opening portion as a seed accommodating portion 425 that is recessed toward the outside of the growth vessel 4 at substantially the center thereof, and the SiC seed crystal is disposed in the opening portion 425.

まず、上記のようにして作製したＳｉＣ種結晶３の成長面（ｃ面）以外の面に、黒鉛板よりなる保護材３８を接着剤で貼付した。
次いで、保護材３８を貼付したＳｉＣ種結晶３を、その成長面３５とＳｉＣ原料粉末４３とが対向するように、成長容器４における上蓋４２の開口部４２５に埋め込んで配置した。このとき、ＳｉＣ種結晶３は、その上記成長面３５と反対側の裏面３６を上記上蓋４２の内表面４２１からＳｉＣ原料の発生源、即ち本体部４１内のＳｉＣ原料粉末４３と離れる方向に後退させて配置した。
次に、成長容器４を加熱して、上記と同様の昇華再析出法によりＳｉＣ種結晶３上にＳｉＣ原料を堆積させて、図４に示すごとくＳｉＣ単結晶３０を得た。 First, the protective material 38 which consists of a graphite plate was affixed on the surface other than the growth surface (c surface) of the SiC seed crystal 3 produced as described above with an adhesive.
Next, the SiC seed crystal 3 to which the protective material 38 was attached was embedded and arranged in the opening 425 of the upper lid 42 in the growth vessel 4 so that the growth surface 35 and the SiC raw material powder 43 faced each other. At this time, the SiC seed crystal 3 recedes from the inner surface 421 of the upper lid 42 with the back surface 36 opposite to the growth surface 35 in a direction away from the source of SiC raw material, that is, the SiC raw material powder 43 in the main body 41. Arranged.
Next, the growth vessel 4 was heated, and a SiC raw material was deposited on the SiC seed crystal 3 by the same sublimation reprecipitation method as described above to obtain a SiC single crystal 30 as shown in FIG.

続いて、上記のようにして得られたＳｉＣ単結晶３０を成形し、これを種結晶として用いてさらにＳｉＣ単結晶を成長させる。
即ち、図５に示すごとく、上記にて得られたＳｉＣ単結晶３０を立方体状に成形し、そのｃ面を成長面５５として露出させてＳｉＣ種結晶５を作製した。その厚み（高さ）は６０ｍｍであった。
このＳｉＣ種結晶５の成長面５５（ｃ面）以外の面に、上記と同様にして黒鉛板よりなる保護材５８を接着剤を用いて貼付し、図５に示すごとく、このＳｉＣ種結晶５を成長容器４における上蓋４２の開口部４２５に埋め込んで配置した。このとき、同図に示すごとく、ＳｉＣ種結晶５は、上記成長面５５の反対側の裏面５６が上蓋４２の内表面４２１からＳｉＣ原料粉末４３と離れる方向に後退するよう配置した。そして、成長容器４を加熱して、図６に示すごとく、上記と同様の昇華再析出法によりＳｉＣ種結晶５上にＳｉＣ原料を堆積させて、ＳｉＣ単結晶５０を得た。 Subsequently, the SiC single crystal 30 obtained as described above is formed, and this is used as a seed crystal to further grow a SiC single crystal.
That is, as shown in FIG. 5, the SiC single crystal 30 obtained above was formed into a cubic shape, and the c-plane was exposed as a growth surface 55 to produce a SiC seed crystal 5. Its thickness (height) was 60 mm.
A protective material 58 made of a graphite plate is attached to a surface other than the growth surface 55 (c-plane) of the SiC seed crystal 5 using an adhesive in the same manner as described above, and as shown in FIG. Was embedded in the opening 425 of the upper lid 42 in the growth vessel 4. At this time, as shown in the figure, the SiC seed crystal 5 was arranged so that the back surface 56 opposite to the growth surface 55 was retracted from the inner surface 421 of the upper lid 42 in a direction away from the SiC raw material powder 43. Then, the growth vessel 4 was heated, and as shown in FIG. 6, a SiC raw material was deposited on the SiC seed crystal 5 by the same sublimation reprecipitation method as described above to obtain a SiC single crystal 50.

本例においては、上記のごとく、ＳｉＣ種結晶からＳｉＣ単結晶を作製し、該ＳｉＣ単結晶を上記ＳｉＣ単結晶として再び用いてＳｉＣ単結晶の成長を繰り替えし行うことにより、ＳｉＣ単結晶の長尺化を図ることができた。また、ＳｉＣ単結晶を繰り返して成長させたときの平均の成長速度は、第１回目の単結晶の成長時とほとんど変わらなかった。即ち、ＳｉＣ単結晶を繰り替えし成長させても成長速度の低下はほとんどなく、短期間で長尺のＳｉＣ単結晶を作製することができた。
また、成長結晶の先細りがなかったことから、ＳｉＣ種結晶からは熱が効率的に放熱されていたと考えられる。また、ＳｉＣ単結晶を成長方向と平行にスライスし、透過光学顕微鏡にて観察を行って結晶性を評価した結果、カーボンインクルージョンやクラック等の発生は観察されず、高品質であった。 In this example, as described above, a SiC single crystal is produced from an SiC seed crystal, and the SiC single crystal is reused as the SiC single crystal to repeat the growth of the SiC single crystal. We were able to plan scale. Moreover, the average growth rate when the SiC single crystal was repeatedly grown was almost the same as that during the first single crystal growth. That is, even if the SiC single crystal was repeatedly grown, the growth rate was hardly reduced, and a long SiC single crystal could be produced in a short period of time.
Moreover, since there was no taper of a growth crystal, it is thought that the heat | fever was efficiently thermally radiated from the SiC seed crystal. Moreover, as a result of slicing the SiC single crystal parallel to the growth direction and observing with a transmission optical microscope and evaluating the crystallinity, the occurrence of carbon inclusions and cracks was not observed, and the quality was high.

また、本例においては、例えば図３及び図４に示すごとく、ＳｉＣ種結晶３の側面部に、該側面部を覆う保護材３８を配設した。
そのため、成長容器４の内側において、該成長容器４の内表面から成長する多結晶がＳｉＣ種結晶３に悪影響を及ぼして該ＳｉＣ種結晶３から成長するＳｉＣ単結晶３０に転位が発生することを防止でき、上記のごとく高品質のＳｉＣ単結晶を得ることができた。 In this example, as shown in FIGS. 3 and 4, for example, a protective material 38 covering the side surface portion is disposed on the side surface portion of the SiC seed crystal 3.
Therefore, inside the growth vessel 4, the polycrystal grown from the inner surface of the growth vessel 4 has an adverse effect on the SiC seed crystal 3, and dislocation occurs in the SiC single crystal 30 grown from the SiC seed crystal 3. As described above, a high-quality SiC single crystal could be obtained.

また、本例においては、例えば図３及び図４に示すごとく、ＳｉＣ種結晶３の側面における成長容器４の外側に位置する部分にも保護材４を配設した。即ち、開口部４２５にＳｉＣ種結晶３を埋め込んで配置したことにより、ＳｉＣ種結晶３における成長容器４の外側に露出した部分にも、その側面に保護材４を配設してある。また、ＳｉＣ種結晶３の裏面３６にも保護材４を配設してある。そのため、成長容器４の外側において、ＳｉＣ種結晶からＳｉＣが昇華してしまうことを防止できた。   In this example, as shown in FIGS. 3 and 4, for example, the protective material 4 is also disposed on the side surface of the SiC seed crystal 3 that is located outside the growth vessel 4. That is, since the SiC seed crystal 3 is embedded in the opening 425 and disposed, the protective material 4 is disposed on the side surface of the SiC seed crystal 3 exposed to the outside of the growth vessel 4. A protective material 4 is also provided on the back surface 36 of the SiC seed crystal 3. Therefore, it was possible to prevent SiC from sublimating from the SiC seed crystal outside the growth vessel 4.

（実施例２）
実施例１においては、ｃ軸方向に繰り返し成長させてＳｉＣ単結晶の長尺化を図ったが、本例は、ＳｉＣ種結晶をｃ軸と垂直な方向（ａ面方向）に繰り返し成長させてＳｉＣ単結晶のｃ面の大口径化を図った例である。
まず、ＳｉＣ単結晶から、成長面として｛１−１００｝面を露出した、厚み３０ｍｍのＳｉＣ種結晶を切り出した。 (Example 2)
In Example 1, the SiC single crystal was elongated by repeatedly growing in the c-axis direction. However, in this example, the SiC seed crystal was repeatedly grown in the direction perpendicular to the c-axis (a-plane direction). This is an example in which the diameter of the c-plane of the SiC single crystal is increased.
First, a SiC seed crystal having a thickness of 30 mm, with the {1-100} plane exposed as a growth surface, was cut out from the SiC single crystal.

続いて、図７に示すごとく、上記にて準備したＳｉＣ種結晶６の成長面６５（｛１−１００｝面）以外の面に、黒鉛板よりなる保護材６８を接着剤を用いて貼付した。
次いで、実施例１と同様の成長容器４を準備し、上記ＳｉＣ種結晶６は、成長容器４における上蓋４２の開口部４２５に埋め込み、その成長面６５と反対側の裏面６６を上蓋４２の内表面４２１からＳｉＣ原料粉末４３と離れる方向に後退させて配置した。そして、図８に示すごとく、成長容器４を加熱して、実施例１と同様に昇華再析出法によりＳｉＣ種結晶６上にＳｉＣ原料を堆積させてＳｉＣ単結晶６０を得た。 Subsequently, as shown in FIG. 7, a protective material 68 made of a graphite plate was attached to a surface other than the growth surface 65 ({1-100} surface) of the SiC seed crystal 6 prepared above using an adhesive. .
Next, the same growth vessel 4 as in Example 1 is prepared, and the SiC seed crystal 6 is embedded in the opening 425 of the upper lid 42 in the growth vessel 4, and the back surface 66 on the opposite side of the growth surface 65 is placed inside the upper lid 42. The surface 421 was disposed so as to recede in a direction away from the SiC raw material powder 43. Then, as shown in FIG. 8, the growth vessel 4 was heated and the SiC raw material was deposited on the SiC seed crystal 6 by the sublimation reprecipitation method in the same manner as in Example 1 to obtain the SiC single crystal 60.

次いで、上記のようにして得られたＳｉＣ単結晶６０を立方体状に成形し、図９に示すごとく、｛１１−２０｝面を成長面６１５として露出するＳｉＣ種結晶６１を作製した。このＳｉＣ種結晶６１の成長面６１５（｛１１−２０｝面）以外の面に、上記と同様に保護材６８を貼付した。そして、図９に示すごとく、この｛１１−２０｝面を成長面６１５として露出するＳｉＣ種結晶６１を、成長容器４における上蓋４２の開口部４２５に埋め込んで、ＳｉＣ種結晶６１における成長面６１５と反対側の裏面６１６が上蓋４２の内表面４２１からＳｉＣ原料粉末４３と離れる方向に後退するようにこれを配置した。そして、成長容器４を加熱して、図１０に示すごとく上記と同様の昇華再析出法によりＳｉＣ種結晶６１上にＳｉＣ原料を堆積させて、ＳｉＣ単結晶６２を得た。   Next, SiC single crystal 60 obtained as described above was formed into a cubic shape, and as shown in FIG. 9, SiC seed crystal 61 exposing {11-20} plane as growth surface 615 was produced. A protective material 68 was attached to a surface other than the growth surface 615 ({11-20} surface) of the SiC seed crystal 61 in the same manner as described above. Then, as shown in FIG. 9, the SiC seed crystal 61 that exposes the {11-20} plane as the growth surface 615 is embedded in the opening 425 of the upper lid 42 in the growth vessel 4 to grow the growth surface 615 in the SiC seed crystal 61. This was arranged so that the back surface 616 opposite to the inner surface 421 of the upper lid 42 was retracted in the direction away from the SiC raw material powder 43. Then, the growth vessel 4 was heated, and an SiC raw material was deposited on the SiC seed crystal 61 by the same sublimation reprecipitation method as described above, as shown in FIG.

次いで、上記のようにして得られたＳｉＣ単結晶６２を立方体状に成形し、図１１に示すごとく、｛０００１｝面を成長面６３５と露出させたＳｉＣ種結晶６３を作製した。このＳｉＣ種結晶６３の成長面６３５（｛０００１｝面）以外の面に、上記と同様にして黒鉛板よりなる保護材６８を接着剤を用いて貼付し、このＳｉＣ種結晶６３を、成長容器４における上蓋４２の開口部４２５に埋め込み、その成長面６３５と反対側の裏面６３６が上蓋４２の内表面４２１からＳｉＣ原料粉末４３と離れる方向に後退するように配置した。そして、成長容器４を加熱して、図１２に示すごとく、上記と同様の昇華再析出法によりＳｉＣ種結晶６３上にＳｉＣ原料を堆積させて、ＳｉＣ単結晶６４を得た。   Next, the SiC single crystal 62 obtained as described above was formed into a cubic shape, and as shown in FIG. 11, a SiC seed crystal 63 having the {0001} plane exposed from the growth surface 635 was produced. A protective material 68 made of a graphite plate is attached to a surface other than the growth surface 635 ({0001} surface) of the SiC seed crystal 63 in the same manner as described above, and the SiC seed crystal 63 is attached to the growth container. 4 is embedded in the opening 425 of the upper lid 42, and the rear surface 636 opposite to the growth surface 635 is disposed so as to recede from the inner surface 421 of the upper lid 42 in a direction away from the SiC raw material powder 43. Then, the growth vessel 4 was heated, and as shown in FIG. 12, a SiC raw material was deposited on the SiC seed crystal 63 by the same sublimation reprecipitation method as described above to obtain a SiC single crystal 64.

上記のごとく、本例においては、まず、成長面としてａ面（｛１１−２０｝面及び｛１−１００｝面）を露出させてＳｉＣの成長を行っている。これは所謂ａ面成長であり、このａ面成長を繰り返し行うことにより、得られるＳｉＣ単結晶のｃ面の大口径化を図ることができる。また、螺旋転位やマイクロパイプ欠陥のほとんどないＳｉＣ単結晶を得ることができる。
また、本例においては、ａ面成長を繰り返した後、さらにｃ面成長を行っている。そのため、螺旋転位やマイクロパイプ欠陥に加えて、積層欠陥のほとんどないＳｉＣ単結晶６４を得ることができる。また、ＳｉＣ単結晶６４は、図１２に示すごとく、大口径で長尺のものとすることができる。 As described above, in this example, first, SiC is grown by exposing the a-plane ({11-20} plane and {1-100} plane) as the growth plane. This is so-called a-plane growth, and by repeating this a-plane growth, the diameter of the c-plane of the obtained SiC single crystal can be increased. In addition, an SiC single crystal having almost no screw dislocations or micropipe defects can be obtained.
In this example, after repeating a-plane growth, c-plane growth is further performed. Therefore, it is possible to obtain SiC single crystal 64 having almost no stacking faults in addition to screw dislocations and micropipe defects. Further, as shown in FIG. 12, the SiC single crystal 64 can have a large diameter and a long length.

また、実施例１と同様に、本例においてもＳｉＣ単結晶の平均の成長速度は通常の単結晶成長時とかわず、ＳｉＣ単結晶を繰り返して成長させても成長速度の低下はほとんどおこらなかった。その結果、大口径かつ長尺のＳｉＣ単結晶を短時間で作製することができた。
また、成長結晶の先細りがなかったことから、ＳｉＣ種結晶からは熱が効率的に放熱されていたと考えられる。また、ＳｉＣ単結晶を成長方向と平行にスライスし、透過光学顕微鏡にて観察を行って結晶性を評価した結果、カーボンインクルージョンやクラック等の発生は観察されず、高品質であった。 As in Example 1, in this example, the average growth rate of the SiC single crystal was not different from that in the normal single crystal growth, and the growth rate was hardly lowered even when the SiC single crystal was repeatedly grown. . As a result, a large-diameter and long SiC single crystal could be produced in a short time.
Moreover, since there was no taper of the growth crystal, it is considered that heat was efficiently radiated from the SiC seed crystal. Moreover, as a result of slicing the SiC single crystal parallel to the growth direction and observing with a transmission optical microscope and evaluating the crystallinity, the occurrence of carbon inclusions and cracks was not observed, and the quality was high.

（実施例３）
本例は、成長面に螺旋転位発生可能領域を有する転位制御種結晶を作製し、該転位制御種結晶を用いて、ＳｉＣ単結晶を作製する例である。
以下、本例について図１３〜図１７を用いて説明する。まず、以下のようにして上記転位制御種結晶を準備する。
具体的には、まず図１３に示すごとく、＜０００１＞方向と略平行な面（｛１−１００｝面）を成長面７１５として露出した、厚さ３０ｍｍのＳｉＣ種結晶７１を準備した。
このＳｉＣ種結晶７１は、ｃ面成長により作製された４Ｈ多形のＳｉＣ単結晶より、＜０００１＞方向と平行な面である｛１−１００｝面を露出するようにして切り出されて作製されたものである。ＳｉＣ種結晶７１は、その内部に螺旋転位７９を螺旋転位密度１００個／ｃｍ2以上有している。 (Example 3)
In this example, a dislocation control seed crystal having a region capable of generating a screw dislocation on the growth surface is produced, and an SiC single crystal is produced using the dislocation control seed crystal.
Hereinafter, this example will be described with reference to FIGS. First, the dislocation control seed crystal is prepared as follows.
Specifically, as shown in FIG. 13, an SiC seed crystal 71 having a thickness of 30 mm was prepared in which a plane ({1-100} plane) substantially parallel to the <0001> direction was exposed as a growth plane 715.
This SiC seed crystal 71 is produced by cutting a 4H polymorphic SiC single crystal produced by c-plane growth so that the {1-100} plane, which is a plane parallel to the <0001> direction, is exposed. It is a thing. The SiC seed crystal 71 has therein screw dislocations 79 having a density of 100 screw dislocations / cm 2 or more.

次に、実施例２と同様の成長容器を準備し、実施例２と同様に該成長容器における上蓋の開口部に上記ＳｉＣ単結晶７１を埋め込み、その裏面を上蓋の内表面から後退させて配置し、昇華再析出法によりＳｉＣ種結晶７１上にＳｉＣ単結晶を成長させた（図７〜図１０参照）。なお、ＳｉＣ種結晶の成長面以外の面には、実施例２と同様に予め黒鉛よりなる保護材を貼付しておく。このようにして、図１４に示すごとく、上記ＳｉＣ種結晶７１を＜１−１００＞方向に成長させて、さらに、図１５に示すごとく、＜１１−２０＞方向に成長させてＳｉＣ単結晶７２を作製した。   Next, a growth vessel similar to that of Example 2 was prepared, and the SiC single crystal 71 was embedded in the opening of the upper lid in the growth vessel, and the rear surface thereof was set back from the inner surface of the upper lid, as in Example 2. Then, a SiC single crystal was grown on the SiC seed crystal 71 by the sublimation reprecipitation method (see FIGS. 7 to 10). In addition, a protective material made of graphite is attached in advance to the surface other than the growth surface of the SiC seed crystal in the same manner as in Example 2. In this way, the SiC seed crystal 71 is grown in the <1-100> direction as shown in FIG. 14, and further grown in the <11-20> direction as shown in FIG. Was made.

このＳｉＣ単結晶７２は、上記ＳｉＣ種結晶７１以外の領域には、螺旋転位７９をほとんど含有していない。続いて、このＳｉＣ単結晶７２より、その｛０００１｝面から８°傾いた面が成長面として露出するように種結晶を切り出し、図１６に示すごとく、これを転位制御種結晶７とした。
このとき、ＳｉＣ種結晶７１の少なくとも一部が残るように上記転位制御種結晶７を切り出すことにより、転位制御種結晶７は、図１６に示すごとく、上記螺旋転位発生可能領域７５として、螺旋転位密度１００個／ｃｍ2以上で螺旋転位を露出する領域を有すると共に、螺旋転位密度１００個／ｃｍ2未満の低密度螺旋転位領域７６を有するものとなる。また、螺旋転位発生可能領域７５は、上記転位制御種結晶７における端部の成長面上の約２５％の領域に形成されていた。 This SiC single crystal 72 contains almost no screw dislocations 79 in a region other than the SiC seed crystal 71. Subsequently, a seed crystal was cut out from the SiC single crystal 72 so that a surface inclined by 8 ° from the {0001} plane was exposed as a growth surface, and this was used as a dislocation control seed crystal 7 as shown in FIG.
At this time, the dislocation control seed crystal 7 is cut out so that at least a part of the SiC seed crystal 71 remains, so that the dislocation control seed crystal 7 becomes a screw dislocation generation region 75 as shown in FIG. It has a region where the screw dislocation is exposed at a density of 100 / cm 2 or more, and a low density screw dislocation region 76 having a screw dislocation density of less than 100 / cm 2 . Further, the screw dislocation generation possible region 75 was formed in a region of about 25% on the growth surface at the end of the dislocation control seed crystal 7.

本例においては、上記のごとく、まず、実施例１及び実施例２と同様の、上蓋に種収容部を有した成長容器を用い、該種収容部に上記ＳｉＣ種結晶を埋め込み、上蓋の内表面からＳｉＣ原料の発生源と離れる方向に後退させて配置し、ａ面成長を行ってＳｉＣ単結晶を作製した。そのため、ｃ面が大口径のＳｉＣ単結晶を得ることができ、さらに上記のごとく、該ＳｉＣ単結晶から種結晶を切り出すことにより、大口径の転位制御種結晶を得ることができた。   In this example, as described above, first, a growth vessel having a seed container in the upper lid, as in Examples 1 and 2, was used, and the SiC seed crystal was embedded in the seed container, The SiC single crystal was produced by performing a-plane growth by arranging it so as to recede from the surface in a direction away from the source of the SiC raw material. Therefore, a SiC single crystal having a large c-plane diameter can be obtained, and as described above, a large-diameter dislocation-controlled seed crystal can be obtained by cutting a seed crystal from the SiC single crystal.

次に、上記転位制御種結晶７を用いて、ＳｉＣ単結晶を作製する。
図１７に示すごとく、螺旋転位制御結晶７は、｛０００１｝面よりオフセット角度６０°以内の面を上記成長面７７として有し、成長中の上記ＳｉＣ単結晶７０に螺旋転位７９を螺旋転位密度１００個／ｃｍ2以上で発生することができる螺旋転位発生可能領域７５を、上記成長面７７上の５０％以下の領域に有すると共に、上記成長面７７上における上記螺旋転位発生可能領域７７以外の領域には、上記成長面７７上に露出している螺旋転位が螺旋転位密度１００個／ｃｍ2未満である低密度螺旋転位領域７６を有する。 Next, a SiC single crystal is produced using the dislocation control seed crystal 7.
As shown in FIG. 17, the screw dislocation control crystal 7 has a surface within an offset angle of 60 ° from the {0001} plane as the growth surface 77, and the screw dislocation density of the screw dislocation 79 is formed in the growing SiC single crystal 70. 100 pieces / cm screw dislocation generation region 75 can be generated by two or more, which has 50% or less area on the growth surface 77, other than the screw dislocation generation region 77 on the growth surface 77 The region has a low density screw dislocation region 76 in which screw dislocations exposed on the growth surface 77 are less than 100 screw dislocation density / cm 2 .

そして、該転位制御種結晶７の上記成長面上に上記ＳｉＣ単結晶を成長させるときにおいては、上記転位制御種結晶７の成長途中の表面である途中表面７０３に、平坦なｃ面ファセット７０５が形成され、かつ該ｃ面ファセット７０５と、上記成長面７７上の上記螺旋転位発生可能領域７５をｃ軸方向又は上記成長面７７に垂直な方向において上記途中表面７０３に投影した領域とが、少なくとも一部で重なるようにＳｉＣ単結晶７０を成長させる。   When the SiC single crystal is grown on the growth surface of the dislocation control seed crystal 7, a flat c-plane facet 705 is formed on the intermediate surface 703 that is a surface in the middle of the growth of the dislocation control seed crystal 7. The c-plane facet 705 formed and at least a region obtained by projecting the helical dislocation generation region 75 on the growth surface 77 onto the intermediate surface 703 in the c-axis direction or the direction perpendicular to the growth surface 77 is at least The SiC single crystal 70 is grown so as to partially overlap.

上記転位制御種結晶上へのＳｉＣ単結晶の成長は、昇華再析出法によりおこなう。また、成長容器としては、図１に示すものと同様の、上蓋２２に周囲よりも突出した台座２２５を有した成長容器２を用いた（図１及び図２参照）。   The growth of the SiC single crystal on the dislocation control seed crystal is performed by a sublimation reprecipitation method. Further, as the growth vessel, the growth vessel 2 having a pedestal 225 projecting from the surroundings on the upper lid 22 was used, as shown in FIG. 1 (see FIGS. 1 and 2).

具体的には、まず、図１７に示すごとく、成長容器の上蓋２２の台座２２５に上記転位制御種結晶７を配置した。このとき、該転位制御種結晶７を、その上記成長面７７とＳｉＣ原料の発生源とが対向するように配置した。
次いで、実施例１と同様に、昇華再析出法により転位制御種結晶７の成長面７７上に、ＳｉＣを堆積させ、ＳｉＣ単結晶７０を成長させた（昇華再析出法）。 Specifically, as shown in FIG. 17, the dislocation control seed crystal 7 was first placed on the base 225 of the upper lid 22 of the growth vessel. At this time, the dislocation control seed crystal 7 was arranged so that the growth surface 77 and the source of the SiC raw material faced each other.
Next, similarly to Example 1, SiC was deposited on the growth surface 77 of the dislocation control seed crystal 7 by the sublimation reprecipitation method to grow the SiC single crystal 70 (sublimation reprecipitation method).

このとき、図１７に示すごとく、成長中のＳｉＣ単結晶７０の途中表面７０３には、｛０００１｝面と略平行なｃ面ファセット７０５が形成される。上記転位制御種結晶７は、｛０００１｝面より８°傾いた面を成長面７７としているため、成長と共に形成されるｃ面ファセット１０５は、途中表面７０３の端部に形成される。
一方、上記転位制御種結晶７の上記螺旋転位発生可能領域７５からは、成長中のＳｉＣ単結晶７０中に螺旋転位７９が継承される。 At this time, as shown in FIG. 17, c-plane facets 705 substantially parallel to the {0001} plane are formed on the intermediate surface 703 of the growing SiC single crystal 70. Since the dislocation control seed crystal 7 has a growth surface 77 that is inclined by 8 ° from the {0001} plane, the c-plane facet 105 formed along with the growth is formed at the end of the intermediate surface 703.
On the other hand, the screw dislocation generation region 75 of the dislocation control seed crystal 7 inherits the screw dislocation 79 in the growing SiC single crystal 70.

本例においては、上記のごとく、螺旋転位発生可能領域７５を転位制御種結晶７の端部に形成し、｛０００１｝面からオフセット角度８°の面を成長面としたことにより、成長と共に形成されるｃ面ファセット７０５と、上記成長面７７上の上記螺旋転位発生可能領域７５をｃ軸方向又は上記成長面７７に垂直な方向において上記途中表面７０３に投影した領域とが、少なくとも一部で重なるようにＳｉＣ単結晶７０が成長する。なお、図１７においては、上記螺旋転位発生可能領域７５をｃ軸方向において途中表面７０３に投影した領域を矢印ａで示し、上記成長面７７に垂直な方向において途中表面７０３に投影した領域を矢印ｂで示した。   In the present example, as described above, the spiral dislocation generation possible region 75 is formed at the end of the dislocation control seed crystal 7 and is formed along with the growth by forming a plane having an offset angle of 8 ° from the {0001} plane. At least a portion of the c-plane facet 705 that is projected onto the intermediate surface 703 in the c-axis direction or the direction perpendicular to the growth surface 77. SiC single crystal 70 grows so as to overlap. In FIG. 17, an area where the spiral dislocation generation possible region 75 is projected onto the intermediate surface 703 in the c-axis direction is indicated by an arrow a, and an area projected onto the intermediate surface 703 in the direction perpendicular to the growth surface 77 is indicated by an arrow. Indicated by b.

そのため、図１７に示すごとく、ＳｉＣ単結晶７０の成長中においては、常にｃ面ファセット７０５内には螺旋転位７９（または貫通欠陥）が存在し続け、４Ｈ多形のステップ供給源として機能した。
その結果、本例において得られたＳｉＣ単結晶７０には、異種多形結晶の二次元核生成が発生することなく、異方位結晶が生じることはなかった。 Therefore, as shown in FIG. 17, during the growth of the SiC single crystal 70, the screw dislocations 79 (or threading defects) always existed in the c-plane facet 705 and functioned as a 4H polymorphic step source.
As a result, in the SiC single crystal 70 obtained in this example, two-dimensional nucleation of heterogeneous polymorphic crystals did not occur, and different orientation crystals did not occur.

また、本例においては、螺旋転位７９は、螺旋転位発生可能領域７５とｃ面ファセット７０５との間の局所的な領域に発生しており、低密度螺旋転位領域７６からは螺旋転位はほとんど継承されていなかった。
そのため、本例において得られたＳｉＣ単結晶７０は、螺旋転位が少なく、高品質でＳｉＣ半導体などの用途に適したものであった。 In this example, the screw dislocation 79 is generated in a local region between the screw dislocation generation region 75 and the c-plane facet 705, and the screw dislocation is almost inherited from the low density screw dislocation region 76. Was not.
Therefore, the SiC single crystal 70 obtained in this example has few screw dislocations and is high quality and suitable for applications such as SiC semiconductors.

（実施例４）
本例は、成長面に螺旋転位発生可能領域を有する転位制御種結晶上に、ＳｉＣ単結晶を繰り返し作製する例である。
以下、本例について、図１８及び図１９を用いて説明する。
まず、上記実施例３と同様にして、ＳｉＣ種結晶として転位制御種結晶７を準備した。この転位制御種結晶７は、｛０００１｝面よりオフセット角度８°の面を成長面７７として有し、螺旋転位発生可能領域７５として、螺旋転位密度１００個／ｃｍ2以上で螺旋転位を露出する領域を有すると共に、螺旋転位密度１００個／ｃｍ2未満の低密度螺旋転位領域７６を有するものである。また、螺旋転位発生可能領域７５は、転位制御種結晶７における端部の成長面上の約２５％の領域に形成されている。また、本例においては、転位制御種結晶７の厚みは３０ｍｍである。
この転位制御種結晶７の成長面７７以外の面には、黒鉛板よりなる保護材７８を接着剤にて貼付した。 (Example 4)
In this example, a SiC single crystal is repeatedly formed on a dislocation control seed crystal having a region capable of generating a screw dislocation on the growth surface.
Hereinafter, this example will be described with reference to FIGS.
First, in the same manner as in Example 3, a dislocation control seed crystal 7 was prepared as an SiC seed crystal. This dislocation control seed crystal 7 has a plane with an offset angle of 8 ° from the {0001} plane as a growth plane 77, and exposes screw dislocations as a screw dislocation generation region 75 at a screw dislocation density of 100 pieces / cm 2 or more. And a low density screw dislocation region 76 having a screw dislocation density of less than 100 / cm 2 . Further, the screw dislocation generation possible region 75 is formed in a region of about 25% on the growth surface at the end of the dislocation control seed crystal 7. In this example, the thickness of the dislocation control seed crystal 7 is 30 mm.
A protective material 78 made of a graphite plate was attached to the surface other than the growth surface 77 of the dislocation control seed crystal 7 with an adhesive.

また、図１８に示すごとく、実施例１と同様の上蓋に種収容部４２５としての開口部を有する成長容器を準備し、成長容器の本体部には、ＳｉＣ原料粉末を供給した。
次いで、保護材７８を貼付した転位制御種結晶７を、実施例１と同様に、成長容器における上蓋４２の開口部４２５に埋め込んで配置した。このとき、転位制御種結晶７は、その成長面７７と反対側の裏面７１１を上蓋４２の内表面４２１からＳｉＣ原料の発生源、即ち本体部内のＳｉＣ原料粉末と離れる方向に後退させて配置した。
次に、成長容器を加熱して、実施例１と同様の昇華再析出法により、転位制御種結晶７上にＳｉＣ原料を堆積させて、ＳｉＣ単結晶７０を成長させた。
本例においては、実施例３と同様に、螺旋転位発生可能領域７５を転位制御種結晶７の端部に形成し、｛０００１｝面からオフセット角度８°の面を成長面としたことにより、成長と共に形成されるｃ面ファセット７０５と、上記成長面７７上の上記螺旋転位発生可能領域７５をｃ軸方向又は上記成長面７７に垂直な方向において上記途中表面７０３に投影した領域とが、少なくとも一部で重なるようにＳｉＣ単結晶７０が成長する。なお、図１８においては、螺旋転位発生可能領域７５をｃ軸方向において途中表面７０３に投影した領域を矢印ａで示し、上記成長面７７に垂直な方向において途中表面７０３に投影した領域を矢印ｂで示してある。 Further, as shown in FIG. 18, a growth vessel having an opening as a seed accommodating portion 425 on an upper lid similar to that in Example 1 was prepared, and SiC raw material powder was supplied to the main body of the growth vessel.
Next, the dislocation control seed crystal 7 to which the protective material 78 was attached was embedded in the opening 425 of the upper lid 42 in the growth vessel in the same manner as in Example 1. At this time, the dislocation control seed crystal 7 is disposed with the back surface 711 opposite to the growth surface 77 set back from the inner surface 421 of the upper lid 42 in a direction away from the source of SiC raw material, that is, the SiC raw material powder in the main body. .
Next, the growth vessel was heated, and an SiC raw material was deposited on the dislocation control seed crystal 7 by the sublimation reprecipitation method similar to that of Example 1, thereby growing the SiC single crystal 70.
In this example, as in Example 3, the screw dislocation generation possible region 75 is formed at the end of the dislocation control seed crystal 7, and the surface having an offset angle of 8 ° from the {0001} plane is used as the growth surface. A c-plane facet 705 formed along with growth, and a region obtained by projecting the helical dislocation generation possible region 75 on the growth surface 77 onto the intermediate surface 703 in the c-axis direction or the direction perpendicular to the growth surface 77. SiC single crystal 70 grows so as to partially overlap. In FIG. 18, a region where the screw dislocation generation possible region 75 is projected onto the intermediate surface 703 in the c-axis direction is indicated by an arrow a, and a region projected onto the intermediate surface 703 in the direction perpendicular to the growth surface 77 is indicated by the arrow b. It is shown by.

そのため、実施例３と同様に、ＳｉＣ単結晶７０の成長中においては、常にｃ面ファセット７０５内には螺旋転位７９（または貫通欠陥）が存在し続け、４Ｈ多形のステップ供給源として機能した。それ故、異方位結晶や螺旋転位が非常に少なく、高品質なＳｉＣ単結晶を得ることができた。   Therefore, similarly to Example 3, during the growth of the SiC single crystal 70, the screw dislocations 79 (or threading defects) always existed in the c-plane facet 705 and functioned as a 4H polymorphic step source. . Therefore, it was possible to obtain a high-quality SiC single crystal with very few different orientation crystals and screw dislocations.

続いて、図１９に示すごとく、転位制御種結晶７上に成長したＳｉＣ単結晶を、転位制御種結晶７の成長面７７と略平行な方向に切断して取りはずした。
そして、ＳｉＣ単結晶を取り外した後の転位制御種結晶７を用いて、その成長面７７上に再びＳｉＣ単結晶を成長させた。
このようにして、ＳｉＣ種結晶としての転位制御種結晶７上にＳｉＣ単結晶を繰り返し成長させることができ、また得られたＳｉＣ単結晶は非常に高品質なものであった。なお、図１９においては、切断して取り外したＳｉＣ単結晶を点線で表してある。 Subsequently, as shown in FIG. 19, the SiC single crystal grown on the dislocation control seed crystal 7 was removed by cutting in a direction substantially parallel to the growth surface 77 of the dislocation control seed crystal 7.
Then, the SiC single crystal was again grown on the growth surface 77 by using the dislocation control seed crystal 7 after the SiC single crystal was removed.
In this way, the SiC single crystal can be repeatedly grown on the dislocation control seed crystal 7 as the SiC seed crystal, and the obtained SiC single crystal has a very high quality. In FIG. 19, the SiC single crystal cut and removed is indicated by a dotted line.

また、本例においては、図１９に示すごとく、転位制御種結晶７上に成長したＳｉＣ単結晶をすべて切断して取り外したが、成長したＳｉＣ単結晶のうちの一部をＳｉＣ種結晶側に残して切断し、これを新たな種結晶として用いることもできる。   Further, in this example, as shown in FIG. 19, all of the SiC single crystal grown on the dislocation control seed crystal 7 was cut and removed, but a part of the grown SiC single crystal was moved to the SiC seed crystal side. It can also be cut off and used as a new seed crystal.

（実施例５）
本例においては、保護材とＳｉＣ種結晶との間に、両者の間に働く熱応力を緩和するための応力緩衝材を配設した例につき、図２０を用いて説明する。
まず、ＳｉＣ単結晶から、厚み３０ｍｍのＳｉＣ種結晶８を切り出した。図２０に示すごとく、上記にて準備したＳｉＣ種結晶８の側面及び成長面８５と反対側の裏面８６に、応力緩衝材８７として柔軟性黒鉛シートを接着剤を用いて貼付した。さらに、ＳｉＣ種結晶８の側面と保護材とで応力緩衝材８７を挟むように、応力緩衝材８７に保護材８８を接着剤で貼付した。また、ＳｉＣ種結晶８の成長面８５と反対側の裏面８６にも、応力緩衝材８７を挟むように保護材８８を貼付した。 (Example 5)
In this example, an example in which a stress buffer material for relaxing thermal stress acting between the protective material and the SiC seed crystal is disposed will be described with reference to FIG.
First, a SiC seed crystal 8 having a thickness of 30 mm was cut out from the SiC single crystal. As shown in FIG. 20, a flexible graphite sheet as a stress buffer material 87 was attached to the side surface of the SiC seed crystal 8 prepared above and the back surface 86 opposite to the growth surface 85 using an adhesive. Further, a protective material 88 was attached to the stress buffer material 87 with an adhesive so that the stress buffer material 87 was sandwiched between the side surface of the SiC seed crystal 8 and the protective material. In addition, a protective material 88 was attached to the back surface 86 opposite to the growth surface 85 of the SiC seed crystal 8 so as to sandwich the stress buffer material 87.

次いで、図２０に示すごとく、実施例１と同様の上蓋４２に開口部４２５を有する成長容器４を準備し、応力緩衝材８７及び保護材８８を貼付したＳｉＣ種結晶８を、上蓋４２の開口部４２５に埋め込んで配置した。このとき、ＳｉＣ種結晶８は、その成長面８５と反対側の裏面８６を上蓋４２の内表面４２１からＳｉＣ原料の発生源、即ち本体部内のＳｉＣ原料粉末４３と離れる方向に後退させて配置した。次に、成長容器４を加熱して、上記と同様の昇華再析出法によりＳｉＣ種結晶８上にＳｉＣ原料を堆積させて、図２０に示すごとくＳｉＣ単結晶８０を得た。   Next, as shown in FIG. 20, the growth vessel 4 having the opening 425 is prepared in the upper lid 42 similar to that of the first embodiment, and the SiC seed crystal 8 to which the stress buffer material 87 and the protective material 88 are pasted is It was embedded in the part 425. At this time, the SiC seed crystal 8 is disposed such that the back surface 86 opposite to the growth surface 85 is set back from the inner surface 421 of the upper lid 42 in a direction away from the source of SiC raw material, that is, the SiC raw material powder 43 in the main body. . Next, the growth vessel 4 was heated, and a SiC raw material was deposited on the SiC seed crystal 8 by the same sublimation reprecipitation method as described above to obtain a SiC single crystal 80 as shown in FIG.

本例においては、保護材８８とＳｉＣ種結晶８との間に応力緩衝材８７を配設した。そのため、ＳｉＣ種結晶８と保護材８８との熱膨張差に起因した応力を緩衝することができる。そのため、ＳｉＣ種結晶８に応力がほとんどかからない状態でＳｉＣ単結晶８０を成長させることができ、格子面の反りやマクロ欠陥の発生を防止することができる。そのため、非常に高品質なＳｉＣ単結晶８０を得ることができた。   In this example, a stress buffer material 87 is disposed between the protective material 88 and the SiC seed crystal 8. Therefore, the stress resulting from the difference in thermal expansion between SiC seed crystal 8 and protective material 88 can be buffered. Therefore, SiC single crystal 80 can be grown in a state where stress is hardly applied to SiC seed crystal 8, and the occurrence of lattice plane warpage and macro defects can be prevented. Therefore, a very high quality SiC single crystal 80 could be obtained.

上記の例においては、応力緩衝材を種結晶と保護材との間に配設したが、図２１に示すごとく、応力緩衝材８７を保護材８８と上蓋４２との間に配設することもできる。
この場合には、保護材８８と上蓋４２との熱膨張差に起因した応力を緩衝することができる。そのため、ＳｉＣ種結晶に応力がほとんどかからない状態でＳｉＣ単結晶を成長させることができ、高品質なＳｉＣ単結晶を得ることができる。 In the above example, the stress buffer material is disposed between the seed crystal and the protective material. However, as shown in FIG. 21, the stress buffer material 87 may be disposed between the protective material 88 and the upper lid 42. it can.
In this case, the stress resulting from the difference in thermal expansion between the protective material 88 and the upper lid 42 can be buffered. Therefore, a SiC single crystal can be grown in a state where stress is hardly applied to the SiC seed crystal, and a high-quality SiC single crystal can be obtained.

（比較例１）
次に、成長容器の上蓋に一体的に形成した台座上にＳｉＣ種結晶を配置して、該ＳｉＣ種結晶上にＳｉＣ単結晶を繰り返し成長させた例について説明する。
本例においては、図２３に示すごとく、成長容器９１として、ＳｉＣ原料粉末９３が供給される本体部９１１と、該本体部９１１から取り外し可能な上蓋９１２とを有する坩堝を用いた。本体部９１１は、ＳｉＣ原料粉末９３や、種結晶、ＳｉＣ単結晶等を出し入れするために、その上部を開口させてあり、上蓋９１２はこの開口部分を塞ぐように配置される。また、上蓋９１２は、周囲よりも突出した台座９１３を有しており、種結晶はこの台座９１３に配置される。 (Comparative Example 1)
Next, an example will be described in which an SiC seed crystal is disposed on a pedestal formed integrally with the upper lid of the growth vessel, and an SiC single crystal is repeatedly grown on the SiC seed crystal.
In this example, as shown in FIG. 23, a crucible having a main body 911 to which SiC raw material powder 93 is supplied and an upper lid 912 that can be removed from the main body 911 is used as the growth container 91. The main body 911 has an opening at the top thereof for taking in and out the SiC raw material powder 93, seed crystal, SiC single crystal and the like, and the upper lid 912 is disposed so as to close the opening. The upper lid 912 has a pedestal 913 protruding from the periphery, and the seed crystal is arranged on the pedestal 913.

上記成長容器９１の本体部９１１内にＳｉＣ原料粉末９３を配置した。また、成長面９５としてｃ面を露出した種結晶９を上蓋９１２の台座９１３に接着剤を用いて固定し、この上蓋９１２を本体部９１１の開口部分に配置した。このとき、ＳｉＣ原料粉末９３と種結晶９の成長面９５とが対向するように、種結晶９は、成長面９５の反対側の面と台座９１３とを接着剤により固定した。   SiC raw material powder 93 was placed in the main body 911 of the growth vessel 91. The seed crystal 9 with the c-plane exposed as the growth surface 95 was fixed to the pedestal 913 of the upper lid 912 using an adhesive, and the upper lid 912 was disposed in the opening of the main body 911. At this time, the seed crystal 9 fixed the surface opposite to the growth surface 95 and the base 913 with an adhesive so that the SiC raw material powder 93 and the growth surface 95 of the seed crystal 9 face each other.

次いで、成長容器９１を減圧不活性雰囲気中で温度２１００〜２４００℃に加熱した。このとき、ＳｉＣ原料粉末９３側の温度を種結晶９側の温度よりも２０〜２００℃高く設定した。これにより、図２３に示すごとく、成長容器９１内のＳｉＣ原料粉末９３が加熱により昇華し、このＳｉＣ原料粉末９３よりも低温の種結晶９上にＳｉＣが堆積し、ＳｉＣ単結晶９０が成長した（昇華再析出法）。
さらに成長を続けると、ＳｉＣ原料粉末９３が昇華により枯渇したため、原料を交換し改めて同じ時間だけ昇華再析出法による成長を行った。 Next, the growth vessel 91 was heated to a temperature of 2100 to 2400 ° C. in a vacuum inert atmosphere. At this time, the temperature on the SiC raw material powder 93 side was set 20 to 200 ° C. higher than the temperature on the seed crystal 9 side. Accordingly, as shown in FIG. 23, SiC raw material powder 93 in growth vessel 91 is sublimated by heating, SiC is deposited on seed crystal 9 at a temperature lower than SiC raw material powder 93, and SiC single crystal 90 is grown. (Sublimation reprecipitation method).
As the growth continued, the SiC raw material powder 93 was depleted by sublimation, so that the raw material was replaced and growth was performed again by the sublimation reprecipitation method for the same time.

その結果、二回目の成長時の成長速度は、一回目の成長速度と比較して極端に遅くなった。また、図２３に示すごとく、本例にて得られたＳｉＣ単結晶９０は、その先端部９０５が先細りしていた。これは成長と共に、単結晶９０からの放熱性が低下したためと考えられる。
また、得られたＳｉＣ単結晶９０を成長方向にスライスし、透過光学顕微鏡にて観察を行って結晶性を評価したところ、継ぎ足し界面にカーボンインクルージョンが観察され、また先端部９０５には、微小なクラックが発生していた。これは、ＳｉＣ単結晶９０の周囲に成長した多結晶９９がＳｉＣ単結晶９０に悪影響を及ぼしたためであると考えられる。なお、図２３においては、ＳｉＣ単結晶の周囲に成長した多結晶９９を２種類のハッチングを用いて表しており、縦線と横線との格子で示した部分は１回目の成長時に発生した多結晶であり、斜め線の格子で表された部分は２回目の成長時に発生した多結晶９９である。 As a result, the growth rate during the second growth was extremely slow compared to the first growth rate. Further, as shown in FIG. 23, the tip portion 905 of the SiC single crystal 90 obtained in this example was tapered. This is considered to be because the heat dissipation from the single crystal 90 decreased with the growth.
Further, when the obtained SiC single crystal 90 was sliced in the growth direction and observed with a transmission optical microscope to evaluate the crystallinity, carbon inclusion was observed at the added interface, and the tip 905 had a minute amount. Cracks have occurred. This is presumably because the polycrystal 99 grown around the SiC single crystal 90 had an adverse effect on the SiC single crystal 90. In FIG. 23, the polycrystal 99 grown around the SiC single crystal is represented by using two types of hatching, and the portion indicated by the lattice of the vertical line and the horizontal line is the polycrystal generated during the first growth. The portion of the crystal, which is represented by the diagonal line lattice, is the polycrystal 99 generated during the second growth.

実施例１にかかる、上蓋に種結晶を配置するための台座を有する成長容器の概略を示す説明図。Explanatory drawing which shows the outline of the growth container concerning Example 1 which has the base for arrange | positioning a seed crystal to an upper cover. 実施例１にかかる、上蓋に種結晶を配置するための台座を有する成長容器を用いて、種結晶上にＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that a SiC single crystal is grown on a seed crystal using the growth container which has the base for arrange | positioning a seed crystal to an upper cover concerning Example 1. FIG. 実施例１にかかる、成長容器の上蓋に形成された種収容部に、ＳｉＣ種結晶を上蓋の内表面から後退させるように配置した様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal was arrange | positioned in the seed accommodating part formed in the upper cover of the growth container concerning Example 1 so that it might reverse | retreat from the inner surface of an upper cover. 実施例１にかかる、成長容器の上蓋の種収容部に配置したＳｉＣ種結晶上に第１回目のＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC single crystal of the 1st time is grown on the SiC seed crystal arrange | positioned at the seed accommodating part of the upper cover of the growth container concerning Example 1. FIG. 実施例１にかかる、第１回目の成長後に得られたＳｉＣ単結晶を種結晶とし、該種結晶を成長容器の上蓋の種収容部に、上蓋の内表面から後退させるように配置した様子を示す説明図。The SiC single crystal obtained after the first growth according to Example 1 was used as a seed crystal, and the seed crystal was disposed in the seed container of the upper lid of the growth vessel so as to be retracted from the inner surface of the upper lid. FIG. 実施例１にかかる、ＳｉＣ種結晶上に第２回目のＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that the 2nd time SiC single crystal is grown on the SiC seed crystal concerning Example 1. FIG. 実施例２にかかる、成長面として｛１１−２０｝面を露出したＳｉＣ種結晶を成長容器の上蓋に形成された種収容部に、上蓋の内表面から後退させるように配置した様子を示す説明図。The description which shows a mode that the SiC seed crystal which exposed {11-20} surface as a growth surface concerning Example 2 was arrange | positioned in the seed accommodating part formed in the upper cover of the growth container so that it might reverse | retreat from the inner surface of an upper cover. Figure. 実施例２にかかる、ＳｉＣ種結晶を＜１１−２０＞方向に成長させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal concerning Example 2 is made to grow in a <11-20> direction. 実施例２にかかる、＜１１−２０＞方向に成長させて得られるＳｉＣ単結晶の｛１−１００｝面を成長面として露出させ、これを種結晶とし、該ＳｉＣ種結晶を成長容器の上蓋に形成された種収容部に、上蓋の内表面から後退させるように配置した様子を示す説明図。The {1-100} plane of the SiC single crystal obtained by growing in the <11-20> direction according to Example 2 is exposed as a growth surface, which is used as a seed crystal, and the SiC seed crystal is used as an upper lid of the growth vessel. Explanatory drawing which shows a mode that it arrange | positioned in the seed accommodating part formed in this so that it might reverse | retreat from the inner surface of an upper cover. 実施例２にかかる、ＳｉＣ種結晶を＜１−１００＞方向に成長させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal concerning Example 2 is made to grow in a <1-100> direction. 実施例２にかかる、＜１１−２０＞方向及び＜１−１００＞方向に成長させたＳｉＣ単結晶の｛０００１｝面を成長面として露出させ、これを種結晶とし、該ＳｉＣ種結晶を成長容器の上蓋に形成された種収容部に、上蓋の内表面から後退させるように配置した様子を示す説明図。The SiC single crystal grown in the <11-20> direction and the <1-100> direction according to Example 2 is exposed as a growth surface, which is used as a seed crystal, and the SiC seed crystal is grown. Explanatory drawing which shows a mode that it arrange | positioned in the seed accommodating part formed in the upper cover of the container so that it might reverse | retreat from the inner surface of an upper cover. 実施例２にかかる、ＳｉＣ種結晶を＜０００１＞方向に成長させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal concerning Example 2 is made to grow in a <0001> direction. 実施例３にかかる、螺旋転位を含有するＳｉＣ種結晶を示す説明図。FIG. 6 is an explanatory view showing an SiC seed crystal containing screw dislocations according to Example 3; 実施例３にかかる、ＳｉＣ種結晶をａ面成長（１回目）させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal concerning Example 3 carries out a surface growth (1st time). 実施例３にかかる、ＳｉＣ種結晶をａ面成長（２回目）させる様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal concerning Example 3 carries out a surface growth (2nd time). 実施例３にかかる、転位制御種結晶を示す説明図。FIG. 6 is an explanatory view showing a dislocation control seed crystal according to Example 3. 実施例３にかかる、転位制御種結晶を用いてＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that a SiC single crystal is grown using the dislocation control seed crystal concerning Example 3. FIG. 実施例４にかかる、成長容器の上蓋に形成された種収容部に、ＳｉＣ種結晶をとして転位制御種結晶を配置し、該転位制御種結晶上にＳｉＣ単結晶を成長させるた様子を示す説明図。Explanation showing a state in which a dislocation control seed crystal is disposed as a SiC seed crystal in a seed container formed on the upper lid of the growth vessel according to Example 4 and a SiC single crystal is grown on the dislocation control seed crystal. Figure. 実施例４にかかる、転位制御種結晶上に成長したＳｉＣ種結晶を切断して取り外した様子を示す説明図。Explanatory drawing which shows a mode that the SiC seed crystal which grew on the dislocation control seed crystal concerning Example 4 was cut | disconnected and removed. 実施例５にかかる、ＳｉＣ種結晶と保護材との間に応力緩衝材を配設して、ＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that a stress buffer material is arrange | positioned between the SiC seed crystal and protective material concerning Example 5, and a SiC single crystal is grown. 実施例５にかかる、保護材と上蓋との間に応力緩衝材を配設して、ＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that a stress buffer material is arrange | positioned between a protective material and an upper cover concerning Example 5, and a SiC single crystal is grown. ＳｉＣ単結晶の主要な面方位を示す説明図。Explanatory drawing which shows the main surface orientation of a SiC single crystal. 比較例にかかる、ＳｉＣ種結晶上に連続してＳｉＣ単結晶を成長させる様子を示す説明図。Explanatory drawing which shows a mode that a SiC single crystal grows continuously on the SiC seed crystal concerning a comparative example.

符号の説明Explanation of symbols

３ ＳｉＣ種結晶
３５ 成長面
３０ ＳｉＣ単結晶
３８ 保護材
４ 成長容器
４１ 本体部
４２ 上蓋
４２５ 種収容部（開口部） DESCRIPTION OF SYMBOLS 3 SiC seed crystal 35 Growth surface 30 SiC single crystal 38 Protective material 4 Growth container 41 Main body part 42 Upper lid 425 Seed accommodating part (opening part)

Claims (10)

成長容器内にＳｉＣ種結晶を配置し、該ＳｉＣ種結晶の成長面上にバルク状のＳｉＣ単結晶を成長させて、ＳｉＣ単結晶を製造する方法において、
上記成長容器としては、ＳｉＣ原料が供給される本体部とその上部に配置される上蓋とを有し、該上蓋に上記成長容器の外部に向けて凹んだ種収容部を形成したものを用い、
上記ＳｉＣ種結晶としては、成長方向に２０ｍｍ以上の厚さを有するものを用い、該ＳｉＣ種結晶を、その上記成長面とＳｉＣ原料の発生源とが対向するよう上記種収容部に埋め込み、上記成長面と反対側の裏面を上記上蓋の内表面から上記ＳｉＣ原料の発生源と離れる方向に後退させて配置することを特徴とするＳｉＣ単結晶の製造方法。 In a method for producing a SiC single crystal by arranging a SiC seed crystal in a growth vessel and growing a bulk SiC single crystal on a growth surface of the SiC seed crystal,
The growth vessel has a main body portion to which SiC raw material is supplied and an upper lid disposed on the main body portion, and uses a seed storage portion that is recessed toward the outside of the growth vessel on the upper lid.
As the SiC seed crystal, one having a thickness of 20 mm or more in the growth direction is used, and the SiC seed crystal is embedded in the seed container so that the growth surface and the source of the SiC raw material face each other. A method for producing a SiC single crystal, wherein the rear surface opposite to the growth surface is disposed so as to recede from the inner surface of the upper lid in a direction away from the source of the SiC raw material. 請求項１において、上記ＳｉＣ種結晶の側面部の少なくとも一部には、該側面部を覆う保護材が配設されていることを特徴とするＳｉＣ単結晶の製造方法。   The method for producing a SiC single crystal according to claim 1, wherein a protective material covering the side surface portion is disposed on at least a part of the side surface portion of the SiC seed crystal. 請求項２において、上記ＳｉＣ種結晶と、上記保護材とは一体的に接合されていることを特徴とするＳｉＣ単結晶の製造方法。   3. The method for producing a SiC single crystal according to claim 2, wherein the SiC seed crystal and the protective material are integrally joined. 請求項２又は３において、上記保護材と上記ＳｉＣ種結晶との間には、両者の間にはたらく熱応力を緩和するための応力緩衝材が配設されていることを特徴とするＳｉＣ単結晶の製造方法。   4. The SiC single crystal according to claim 2, wherein a stress buffering material for relaxing thermal stress acting between the protective material and the SiC seed crystal is disposed between the protective material and the SiC seed crystal. Manufacturing method. 請求項２〜４のいずれか一項において、上記保護材と上記上蓋との間には、両者の間に働く熱応力を緩和するための応力緩衝材が配設されていることを特徴とするＳｉＣ単結晶の製造方法。   The stress buffer material for relieving the thermal stress which acts between both in the said protective material and the said upper cover is arrange | positioned in any one of Claims 2-4. A method for producing a SiC single crystal. 請求項１〜５のいずれか１項において、上記ＳｉＣ種結晶として、ｃ面よりオフセット角度６０°以内の面を上記成長面として露出させたものを用いることを特徴とするＳｉＣ単結晶の製造方法。   6. The method for producing a SiC single crystal according to claim 1, wherein the SiC seed crystal is one in which a surface within an offset angle of 60 degrees from the c-plane is exposed as the growth surface. . 請求項１〜５のいずれか１項において、上記ＳｉＣ種結晶として、ｃ面と略垂直な面を上記成長面として露出させたものを用いることを特徴とするＳｉＣ単結晶の製造方法。   6. The method for producing a SiC single crystal according to claim 1, wherein the SiC seed crystal is one in which a surface substantially perpendicular to the c-plane is exposed as the growth surface. 請求項７において、上記ＳｉＣ種結晶は、螺旋転位密度が１００個／ｃｍ2以上の領域を少なくとも一部に有することを特徴とするＳｉＣ単結晶の製造方法。 In claim 7, the SiC seed crystal, manufacturing method of SiC single crystal screw dislocation density is characterized by having at least a portion of 100 / cm 2 or more regions. 請求項１〜５のいずれか１項において、上記ＳｉＣ種結晶として、｛０００１｝面よりオフセット角度６０°以内の面を上記成長面として有し、成長中の上記ＳｉＣ単結晶に螺旋転位を螺旋転位密度１００個／ｃｍ2以上で発生することができる螺旋転位発生可能領域を、上記成長面上の５０％以下の領域に有すると共に、上記成長面上における上記螺旋転位発生可能領域以外の領域には、上記成長面上に露出している螺旋転位が螺旋転位密度１００個／ｃｍ2未満である低螺旋転位密度領域を有する転位制御種結晶を用い、該転位制御種結晶の上記成長面上に上記ＳｉＣ単結晶を成長させるときにおいては、該ＳｉＣ単結晶の成長途中の表面である途中表面に、平坦なｃ面ファセットが形成され、かつ該ｃ面ファセットと、上記成長面上の上記螺旋転位発生可能領域をｃ軸方向又は上記成長面に垂直な方向において上記途中表面に投影した領域とが、少なくとも一部で重なるようにＳｉＣ単結晶を成長させることを特徴とするＳｉＣ単結晶の製造方法。 6. The SiC seed crystal according to claim 1, wherein the SiC seed crystal has a plane having an offset angle of 60 ° or less from the {0001} plane as the growth plane, and spiral dislocations are formed on the growing SiC single crystal. The dislocation density generation region capable of being generated at a dislocation density of 100 / cm 2 or more is included in a region of 50% or less on the growth surface, and the region other than the region capable of generating the screw dislocation on the growth surface. Uses a dislocation control seed crystal having a low screw dislocation density region in which the screw dislocations exposed on the growth surface are less than 100 screw dislocation densities / cm 2 , and on the growth surface of the dislocation control seed crystal. When the SiC single crystal is grown, a flat c-plane facet is formed on the intermediate surface, which is a surface in the middle of the growth of the SiC single crystal, and the c-plane facet is formed on the growth surface. A SiC single crystal is grown such that a region in which a screw dislocation generation region is projected onto the intermediate surface in the c-axis direction or a direction perpendicular to the growth surface overlaps at least partially. Production method. 請求項１〜９のいずれか１項において、上記ＳｉＣ種結晶上に成長したＳｉＣ単結晶を、上記ＳｉＣ種結晶の上記成長面と略平行な方向に切断して取り外し、該ＳｉＣ種結晶上に再びＳｉＣ単結晶を成長させることを特徴とするＳｉＣ単結晶の製造方法。   The SiC single crystal grown on the SiC seed crystal according to any one of claims 1 to 9, is cut and removed in a direction substantially parallel to the growth surface of the SiC seed crystal, and the SiC single crystal is removed on the SiC seed crystal. A method for producing a SiC single crystal, wherein the SiC single crystal is grown again.
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