JP2008239371A - Silicon carbide single crystal substrate and method for manufacturing the same - Google Patents
Silicon carbide single crystal substrate and method for manufacturing the same Download PDFInfo
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- 239000013078 crystal Substances 0.000 title claims abstract description 209
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 131
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 128
- 239000000758 substrate Substances 0.000 title claims abstract description 112
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 title abstract description 34
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 39
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 36
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 36
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 31
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 30
- 239000010703 silicon Substances 0.000 claims abstract description 30
- 230000004907 flux Effects 0.000 claims abstract description 19
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 29
- 239000002994 raw material Substances 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 7
- 239000007791 liquid phase Substances 0.000 claims description 6
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 3
- 238000005303 weighing Methods 0.000 claims description 2
- 239000012856 weighed raw material Substances 0.000 claims 1
- 239000000155 melt Substances 0.000 abstract description 41
- 239000010408 film Substances 0.000 description 12
- 239000000463 material Substances 0.000 description 10
- 230000003287 optical effect Effects 0.000 description 9
- 239000010409 thin film Substances 0.000 description 9
- 229910002804 graphite Inorganic materials 0.000 description 8
- 239000010439 graphite Substances 0.000 description 8
- 238000002441 X-ray diffraction Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 238000005092 sublimation method Methods 0.000 description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 5
- 229910052721 tungsten Inorganic materials 0.000 description 5
- 239000010937 tungsten Substances 0.000 description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 3
- 150000001342 alkaline earth metals Chemical class 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910018540 Si C Inorganic materials 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 238000000441 X-ray spectroscopy Methods 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- ARNWQMJQALNBBV-UHFFFAOYSA-N lithium carbide Chemical compound [Li+].[Li+].[C-]#[C-] ARNWQMJQALNBBV-UHFFFAOYSA-N 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
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Abstract
Description
本発明は、特に光デバイスや電子デバイスの基板材料として好適な、炭化珪素（ＳｉＣ
）単結晶基板とその製造方法に関する。
The present invention is particularly suitable for silicon carbide (SiC) as a substrate material for optical devices and electronic devices.
) A single crystal substrate and a method for manufacturing the same.
炭化珪素（ＳｉＣ）単結晶は、熱的および化学的に非常に安定な半導体材料であり、珪
素（Ｓｉ）に比べ、バンドギャップが２〜３倍、熱伝導率が約３倍、絶縁破壊電圧が約１
０倍、飽和電子速度が約２倍大きいという優れた特性を有している。このような優れた特
性から、炭化珪素単結晶はシリコンデバイスの限界を超えるパワーデバイスや、高温で動
作する耐環境デバイスの基板材料としての応用が期待されている。
Silicon carbide (SiC) single crystal is a thermally and chemically very stable semiconductor material, and has a band gap of 2 to 3 times, a thermal conductivity of about 3 times, and a dielectric breakdown voltage compared to silicon (Si). About 1
It has excellent characteristics of 0 times and saturation electron velocity about twice as large. Due to such excellent characteristics, silicon carbide single crystal is expected to be used as a substrate material for power devices exceeding the limits of silicon devices and environmental resistant devices operating at high temperatures.
炭化珪素は多くの結晶多形（ポリタイプ）が存在する。この結晶多形とは化学量論的に
は同じ組成でありながら原子の積層の周期が（Ｃ軸方向にのみ）異なる多くの結晶構造を
取るものである。代表的なポリタイプは２Ｈ，３Ｃ，４Ｈ，６Ｈ，１５Ｒである。Ｈは六
方晶、Ｃは立方晶、Ｒは菱面体構造を表している。数字は積層方向（Ｃ軸方向）の一周期
中に含まれるＳｉ−Ｃ単位層の数を意味する。現在、上市されている炭化珪素単結晶は３
Ｃと４Ｈ，６Ｈであり、なかでも４Ｈ炭化珪素単結晶は、バンドギャップと飽和電子速度
の特性が良いことから、光デバイスや電子デバイスの基板材料として実用化研究の中心的
な材料となっている。
Silicon carbide has many crystal polymorphs (polytypes). This crystal polymorph has many crystal structures having the same stoichiometric composition but different atomic period (only in the C-axis direction). Typical polytypes are 2H, 3C, 4H, 6H, 15R. H represents a hexagonal crystal, C represents a cubic crystal, and R represents a rhombohedral structure. The numbers mean the number of Si-C unit layers included in one cycle of the stacking direction (C-axis direction). There are currently 3 silicon carbide single crystals on the market.
C, 4H, and 6H. Among them, 4H silicon carbide single crystal has a good band gap and saturated electron velocity characteristics, and thus has become a central material for practical research as a substrate material for optical devices and electronic devices. Yes.
２Ｈ炭化珪素単結晶は、４Ｈ炭化珪素単結晶よりバンドギャップと飽和電子速度の特性
がより良いことが知られている。２Ｈ炭化珪素単結晶の基板材料を得ることができれば、
より高性能な光デバイスや電子デバイスが得られるものである。
It is known that 2H silicon carbide single crystal has better band gap and saturation electron velocity characteristics than 4H silicon carbide single crystal. If a substrate material of 2H silicon carbide single crystal can be obtained,
Higher performance optical devices and electronic devices can be obtained.
炭化珪素単結晶の成長方法としては、気相成長法の昇華法とＣＶＤ法、アチソン法、液
相成長法が知られている。気相成長法には昇華法とＣＶＤ法がある。昇華法は、閉ざされ
た黒鉛坩堝中で炭化珪素粉末を２０００℃以上の高温下で昇華させ、坩堝の低温部に設置
した種結晶基板上に再結晶化させる方法である。現在、上市されている４Ｈと６Ｈ炭化珪
素単結晶基板の多くは、この昇華法で製造されている。しかし、昇華法で成長させた単結
晶にはマイクロパイプ欠陥や積層欠陥の発生、結晶多形ができ易いという問題がある。Ｃ
ＶＤ法は原料をシランガスと炭化水素系ガスで供給するため、原料供給量が少なく厚い膜
が得られない。そのため、光デバイスや電子デバイスの基板材料として要求される、バル
ク単結晶を得ることが難しい。
As a method for growing a silicon carbide single crystal, a vapor phase sublimation method, a CVD method, an atchison method, and a liquid phase growth method are known. The vapor phase growth method includes a sublimation method and a CVD method. The sublimation method is a method in which silicon carbide powder is sublimated at a high temperature of 2000 ° C. or higher in a closed graphite crucible and recrystallized on a seed crystal substrate placed in a low temperature portion of the crucible. Many of the 4H and 6H silicon carbide single crystal substrates currently on the market are manufactured by this sublimation method. However, single crystals grown by the sublimation method have problems that micropipe defects and stacking faults are easily generated, and that crystal polymorphism is easily formed. C
In the VD method, since raw materials are supplied by silane gas and hydrocarbon gas, the raw material supply amount is small and a thick film cannot be obtained. Therefore, it is difficult to obtain a bulk single crystal that is required as a substrate material for optical devices and electronic devices.
アチソン法は、容器内に設けられた黒鉛電極の周りに珪砂とコークスを詰めて、黒鉛電
極に通電し２０００℃以上の高温とし、炭化珪素単結晶を得る方法である。アチソン法は
炭化珪素研磨材の製造技術として確立され産業に貢献している。しかし、光デバイスや電
子デバイスの基板材料としては、不純物が多く高純度品が得難いことと、大型の単結晶を
作ることができないという問題がある。
The Atchison method is a method in which silica graphite and coke are packed around a graphite electrode provided in a container, and the graphite electrode is energized to a high temperature of 2000 ° C. or higher to obtain a silicon carbide single crystal. The Atchison method has been established as a technology for manufacturing silicon carbide abrasives and contributes to the industry. However, as a substrate material for optical devices and electronic devices, there are problems that there are many impurities and it is difficult to obtain a high-purity product and that a large single crystal cannot be produced.
液相成長法は、黒鉛坩堝内で珪素もしくは珪素化合物を融解し、その融液中に黒鉛坩堝
から炭素を溶解させて炭化珪素単結晶を析出させる方法である。しかし、珪素融液中への
炭素の溶解量が小さいため大きな単結晶を得ることが困難であった。
The liquid phase growth method is a method in which silicon or a silicon compound is melted in a graphite crucible, and carbon is dissolved in the melt from the graphite crucible to precipitate a silicon carbide single crystal. However, since the amount of carbon dissolved in the silicon melt is small, it has been difficult to obtain a large single crystal.
前述した液相成長法の問題点を解決する方法として、珪素と炭素、少なくとも１種の遷
移金属を含む原料を黒鉛坩堝内で加熱溶融して融液を作り、この融液を冷却するか融液に
温度勾配を作り、種結晶基板上に炭化珪素単結晶を生成する方法が、特許文献１から３に
開示されている。特許文献１で得られているのは３Ｃ炭化珪素単結晶、特許文献２で得ら
れているのは６Ｈ炭化珪素単結晶である。融液を冷却する方法を温度降下法、融液に温度
勾配を作る方法を温度勾配法と称している。
As a method for solving the problems of the liquid phase growth method described above, a raw material containing silicon, carbon, and at least one transition metal is heated and melted in a graphite crucible to form a melt, and the melt is cooled or melted. Patent Documents 1 to 3 disclose a method for producing a silicon carbide single crystal on a seed crystal substrate by creating a temperature gradient in the liquid. Patent Document 1 obtains a 3C silicon carbide single crystal, and Patent Document 2 obtains a 6H silicon carbide single crystal. A method of cooling the melt is called a temperature drop method, and a method of creating a temperature gradient in the melt is called a temperature gradient method.
高品質の炭化珪素単結晶を安定に、また低コストで製造するには低温で成長させること
が必要である。前述の特許文献１〜３の実施例でも、結晶成長に必要な温度は１４５０℃
以上である。特許文献４には、アルカリ金属［特にリチウム（Ｌｉ）］フラックス中で珪
素と炭素の融液を作って反応させることで、６００℃〜１４００℃と低温で、２Ｈ炭化珪
素単結晶を成長させている。
In order to produce a high-quality silicon carbide single crystal stably and at low cost, it is necessary to grow it at a low temperature. Also in the above-described Examples of Patent Documents 1 to 3, the temperature necessary for crystal growth is 1450 ° C.
That's it. In Patent Document 4, a 2H silicon carbide single crystal is grown at a low temperature of 600 ° C. to 1400 ° C. by reacting a silicon and carbon melt in an alkali metal [especially lithium (Li)] flux. Yes.
非特許文献１と２に記載されている改良レーリー法（昇華法の一例）で得られる種結晶
面と成長結晶の関係は、６Ｈ種結晶のＣ面（０００−１）では４Ｈもしくは６Ｈの成長結
晶、４ＨＣ面種結晶では４Ｈが支配的な成長結晶である。Ｓｉ面（０００１）では４Ｈと
６Ｈの何れも６Ｈの成長結晶であり、１５Ｒがしばしば混在する。これらの関係から、４
Ｈ炭化珪素単結晶もしくは６Ｈ炭化珪素単結晶上に、２Ｈ炭化珪素単結晶を成長させるこ
とはできていなかった。
The relationship between the seed crystal plane obtained by the modified Rayleigh method (an example of the sublimation method) described in Non-Patent Documents 1 and 2 and the growth crystal is 4H or 6H growth on the C plane (000-1) of the 6H seed crystal. In crystal, 4HC plane seed crystal, 4H is the dominant growth crystal. On the Si plane (0001), both 4H and 6H are 6H growth crystals, and 15R is often mixed. From these relationships, 4
A 2H silicon carbide single crystal could not be grown on the H silicon carbide single crystal or the 6H silicon carbide single crystal.
特許文献４には、６Ｈ−ＳｉＣ結晶基板上もしくは４Ｈ−ＳｉＣ結晶基板上に２Ｈ−Ｓ
ｉＣ単結晶を製造することが好ましいとの記載があるが、６Ｈ−ＳｉＣ（４Ｈ−ＳｉＣ）
結晶基板のどの結晶面に製造するかの詳細な記載がなく、また実施例にも記載はない。特
許文献４の実施例では、種結晶上に２Ｈ−ＳｉＣを成長させたものではなく、Ｌｉフラッ
クス中に珪素と炭素の融液を作って反応させたものである。２Ｈ炭化珪素単結晶基板（膜
）を電子デバイスや光デバイスに用いるには、良質で大面積が要求されるだけでなく厚み
も必要である。種結晶基板上に形成された２Ｈ炭化珪素単結晶膜に電子デバイスを形成す
る場合、少なくとも１０μｍ程度の厚みは必要となってくる。３０μｍ厚以上の２Ｈ炭化
珪素単結晶膜が得られれば、電子デバイス形成後種結晶基板を研磨等で除去した後、電子
デバイスに個片化することで、２Ｈ炭化珪素単結晶基板上に形成された電子デバイスを得
ることができる。そのため、大面積で厚みの厚い２Ｈ炭化珪素単結晶基板を、工業的によ
り効率的でより安定的により低コストで生産できる技術検討が必要である。
In Patent Document 4, 2H—S is formed on a 6H—SiC crystal substrate or a 4H—SiC crystal substrate.
Although it is described that it is preferable to produce an iC single crystal, 6H-SiC (4H-SiC)
There is no detailed description of which crystal plane of the crystal substrate is manufactured, and there is no description in the examples. In the example of Patent Document 4, 2H—SiC is not grown on a seed crystal, but a reaction is performed by forming a melt of silicon and carbon in a Li flux. In order to use a 2H silicon carbide single crystal substrate (film) for an electronic device or an optical device, not only high quality and a large area are required, but also a thickness is required. When an electronic device is formed on a 2H silicon carbide single crystal film formed on a seed crystal substrate, a thickness of at least about 10 μm is required. If a 2H silicon carbide single crystal film having a thickness of 30 μm or more is obtained, it is formed on the 2H silicon carbide single crystal substrate by removing the seed crystal substrate by polishing or the like after the formation of the electronic device and then separating it into electronic devices. Electronic devices can be obtained. Therefore, it is necessary to study the technology that can produce a 2H silicon carbide single crystal substrate having a large area and a large thickness, industrially more efficiently, more stably, and at a lower cost.
本願発明は、より安定的により効率的に、４Ｈもしくは６Ｈ炭化珪素単結晶基板上に２
Ｈ炭化珪素単結晶が形成された基板と、その製造方法を提供することを目的とする。
The present invention is more stable and more efficient on a 4H or 6H silicon carbide single crystal substrate.
It is an object of the present invention to provide a substrate on which an H silicon carbide single crystal is formed and a method for manufacturing the same.
本願発明の炭化珪素単結晶基板は、４Ｈ炭化珪素単結晶もしくは６Ｈ炭化珪素単結晶の
Ｃ面［（０００−１）面］に、２Ｈ炭化珪素単結晶が形成されることが好ましい。
In the silicon carbide single crystal substrate of the present invention, a 2H silicon carbide single crystal is preferably formed on the C plane [(000-1) plane] of a 4H silicon carbide single crystal or a 6H silicon carbide single crystal.
リチウムフラックス中に珪素と炭素を溶解した融液に、種結晶基板となる４Ｈもしくは
６Ｈ炭化珪素単結晶のＣ面［（０００−１）面］を浸漬させ、浸漬させた状態を所定の時
間保持した後に温度を降下させる温度降下法で、種結晶のＣ面［（０００−１）面］上に
ＬＰＥ（Ｌｉｑｕｉｄ Ｐｈａｓｅ Ｅｐｉｔａｘｉａｌ）成長で、２Ｈ炭化珪素単結晶
を成長させる。融液に温度勾配を作る温度勾配法で、種結晶基板のＣ面［（０００−１）
面］上に２Ｈ炭化珪素単結晶をＬＰＥ成長させることもできる。
A C-plane [(000-1) plane] of a 4H or 6H silicon carbide single crystal serving as a seed crystal substrate is immersed in a melt obtained by dissolving silicon and carbon in lithium flux, and the immersed state is maintained for a predetermined time. Then, a 2H silicon carbide single crystal is grown on the C-plane [(000-1) plane] of the seed crystal by LPE (Liquid Phase Epitaxial) growth by a temperature drop method in which the temperature is lowered. C-plane [(000-1) of seed crystal substrate by temperature gradient method to create temperature gradient in melt
2H silicon carbide single crystal can be grown on the surface].
融液の組成はモル比で、リチウム：珪素：炭素＝１．０：０．１〜１．０：０．１〜１
．０とすることができる。炭素の供給形態は黒鉛容器から供給される炭素や純炭素を添加
することができる。また、炭化リチウムの使用やメタンやプロパンガスのような炭化水素
ガスで供給することもできる。
The composition of the melt is molar ratio: lithium: silicon: carbon = 1.0: 0.1 to 1.0: 0.1-1
. It can be set to zero. Carbon supplied from a graphite container or pure carbon can be added as a form of supplying carbon. Further, lithium carbide can be used or a hydrocarbon gas such as methane or propane gas can be supplied.
フラックスのリチウムには、ナトリウム（Ｎａ）やカリウム（Ｋ）等のアルカリ金属や
、マグネシウム（Ｍｇ）やカルシウム（Ｃａ）等のアルカリ土類金属を不純物として含ん
でいても良いものである。これら不純物のアルカリ金属やアルカリ土類金属は、フラック
スとして機能するため含有量を特に規定する必要がない。リチウムに含まれる不純物のア
ルカリ金属やアルカリ土類金属を許容することで、安価なリチウムを使用することができ
、製造コストの低減が図れる。３Ｎ以上の純度を有する原料を用いることができる。
The lithium of the flux may contain an alkali metal such as sodium (Na) or potassium (K) or an alkaline earth metal such as magnesium (Mg) or calcium (Ca) as impurities. The content of these impurities, alkali metals and alkaline earth metals, does not need to be specified because they function as flux. By allowing the alkali metal or alkaline earth metal impurity contained in lithium, inexpensive lithium can be used, and the manufacturing cost can be reduced. A raw material having a purity of 3N or more can be used.
また、２Ｈ炭化珪素のＬＰＥ成長時にＮ型やＰ型元素をドープすることができる。２Ｈ
炭化珪素単結晶にドープするドーピング元素をフラックス中に含有させる事で、Ｎ型やＰ
型の２Ｈ炭化珪素単結晶を得ることができる。Ｎ型ドーピング材（元素）としては、窒素
（Ｎ）や燐（Ｐ）、Ｐ型ドーピング材としてはアルミニウム（Ａｌ）やホウ素（Ｂ）を選
択することができる。
Further, N-type or P-type elements can be doped during LPE growth of 2H silicon carbide. 2H
By adding a doping element to the silicon carbide single crystal in the flux, N-type and P
Type 2H silicon carbide single crystal can be obtained. Nitrogen (N) or phosphorus (P) can be selected as the N-type doping material (element), and aluminum (Al) or boron (B) can be selected as the P-type doping material.
本願発明の炭化珪素単結晶基板は、４Ｈ炭化珪素単結晶もしくは６Ｈ炭化珪素単結晶の
Ｃ面［（０００−１）面］の傾きが、８度以下であることが好ましい。
In the silicon carbide single crystal substrate of the present invention, the inclination of the C plane [(000-1) plane] of 4H silicon carbide single crystal or 6H silicon carbide single crystal is preferably 8 degrees or less.
ジャスト（０００−１）面であることが好ましいが、（０００−１）面より８度以下の
オフアングル面であれば、ジャスト面と同等の物理特性を持つ２Ｈ炭化珪素単結晶が得ら
れる。８度以下のオフアングル面まで使用できるため、種単結晶基板の加工が容易となり
、製造コストの低減が図れる。
Although it is preferably the just (000-1) plane, if it is an off-angle plane of 8 degrees or less from the (000-1) plane, a 2H silicon carbide single crystal having physical properties equivalent to the just plane can be obtained. Since an off-angle surface of 8 degrees or less can be used, the seed single crystal substrate can be easily processed, and the manufacturing cost can be reduced.
本願発明の炭化珪素単結晶基板は、２Ｈ炭化珪素単結晶が液相中でエピタキシャル成長
したＬＰＥ膜であることが好ましい。
The silicon carbide single crystal substrate of the present invention is preferably an LPE film in which a 2H silicon carbide single crystal is epitaxially grown in a liquid phase.
リチウムフラックス中に珪素と炭素を溶解した融液中に、４Ｈもしくは６Ｈ炭化珪素単
結晶の種単結晶基板を浸漬させた状態で、所定時間保持した後温度を下げるか温度勾配を
設けて、種単結晶基板上に２Ｈ炭化珪素単結晶をＬＰＥ成長させる。融液中で種単結晶基
板の位置や保持角度を一定とするため、種結晶基板保持治具を用いていることが好ましい
。種結晶基板の位置が不安定であると、温度勾配法で所定の温度差に制御できないため、
ＬＰＥ膜の成長速度等にばらつきが発生する危険性がある。種結晶基板のＣ面が坩堝の底
面と接触するような事になると、２Ｈ炭化珪素単結晶のＬＰＥ成長が阻害されることが考
えられる。
In a state in which a seed single crystal substrate of 4H or 6H silicon carbide single crystal is immersed in a melt obtained by dissolving silicon and carbon in lithium flux, the temperature is lowered or a temperature gradient is provided after holding for a predetermined time. A 2H silicon carbide single crystal is grown on a single crystal substrate by LPE. In order to make the position and holding angle of the seed single crystal substrate constant in the melt, it is preferable to use a seed crystal substrate holding jig. If the position of the seed crystal substrate is unstable, it cannot be controlled to a predetermined temperature difference by the temperature gradient method.
There is a risk of variations in the growth rate of the LPE film. If the C surface of the seed crystal substrate comes into contact with the bottom surface of the crucible, it is considered that LPE growth of the 2H silicon carbide single crystal is hindered.
種結晶基板保持治具は、融液と接触しているので、溶融リチウムに対し耐蝕性を有する
必要がある。タングステン（Ｗ）やタングステン基合金、モリブデン（Ｍｏ）基合金、炭
化珪素セラミックで製作することが好ましい。
Since the seed crystal substrate holding jig is in contact with the melt, it is necessary to have corrosion resistance against the molten lithium. It is preferable to manufacture with tungsten (W), tungsten base alloy, molybdenum (Mo) base alloy, or silicon carbide ceramic.
本願発明の炭化珪素単結晶基板は、２Ｈ炭化珪素単結晶の厚み（ＬＰＥ膜厚）が３０μ
ｍ以上であることが好ましい。
The silicon carbide single crystal substrate of the present invention has a 2H silicon carbide single crystal thickness (LPE film thickness) of 30 μm.
It is preferable that it is m or more.
２Ｈ炭化珪素単結晶の厚み（ＬＰＥ膜厚）が３０μｍ以上あると、電子デバイスや光デ
バイスを２Ｈ炭化珪素単結晶基板面に形成した後、種結晶基板部を研磨等で除去した後、
電子デバイスに個片化することで、２Ｈ炭化珪素単結晶のみで形成された基板上に、電子
デバイスや光デバイスを設けることができ、高性能化が期待できる。電子デバイスや光デ
バイス等を形成する間には、フォトリソ工程や製膜工程、ミリング工程等で、基板搬送や
治具への着脱など、数多く基板を取扱うものである。これら取扱い時に、基板が破損しな
いように、種結晶基板の除去は後工程に行うのが好ましい。
When the thickness of the 2H silicon carbide single crystal (LPE film thickness) is 30 μm or more, after the electronic device or the optical device is formed on the 2H silicon carbide single crystal substrate surface, the seed crystal substrate portion is removed by polishing,
By separating into individual electronic devices, electronic devices and optical devices can be provided on a substrate formed of only 2H silicon carbide single crystal, and high performance can be expected. During the formation of electronic devices, optical devices, etc., a large number of substrates are handled, such as substrate transportation and attachment / detachment to jigs, in a photolithography process, a film forming process, a milling process, and the like. It is preferable to remove the seed crystal substrate in a subsequent process so that the substrate is not damaged during handling.
本願発明の炭化珪素単結晶基板の製造方法は、リチウムと珪素、炭素の原料を秤量する
工程、４Ｈ炭化珪素単結晶もしくは６Ｈ炭化珪素単結晶の種結晶基板を作製する工程、秤
量した原料と種結晶基板を坩堝に入れ、坩堝を密封容器に密封する工程、密封容器を加熱
しリチウムフラックス中で珪素と炭素の融液を作製する工程、種結晶基板のＣ面［（００
０−１）面］に２Ｈ炭化珪素単結晶をＬＰＥ成長させる工程、密封容器冷却後炭化珪素単
結晶基板取り出す工程を有することが好ましい。
The method for producing a silicon carbide single crystal substrate of the present invention includes a step of weighing lithium, silicon, and carbon raw materials, a step of preparing a seed crystal substrate of 4H silicon carbide single crystal or 6H silicon carbide single crystal, and a weighted raw material and seed. Placing the crystal substrate in a crucible and sealing the crucible in a sealed container; heating the sealed container to produce a melt of silicon and carbon in lithium flux; and C-plane [(00
It is preferable to include a step of LPE growing a 2H silicon carbide single crystal on the (0-1) plane] and a step of taking out the silicon carbide single crystal substrate after cooling the sealed container.
リチウムフラックス中で珪素と炭素の融液を作製する工程は、不活性ガス雰囲気のグロ
ーブボックス内で、種結晶基板保持治具に種結晶基板のＣ面が接触しない様に保持して坩
堝に入れる。次に、リチウムと珪素、炭素を秤量して坩堝に入れる。坩堝は、更に耐熱を
有する密封容器に入れ密封する。グローブボックスから密封容器を取り出し、電気炉を用
い加熱して融液を作る。加熱温度はリチウムの沸点（１３４７℃）以下とし、好ましくは
７００℃〜１０００℃である。電気炉で密封容器中の坩堝が加熱されると、リチウムが融
解してリチウムフラックスが形成され、次いでリチウムフラックス中に珪素と炭素が溶解
して、珪素と炭素の融液を得る。
The step of preparing a melt of silicon and carbon in a lithium flux is carried out in a crucible while holding the seed crystal substrate holding jig so that the C-plane of the seed crystal substrate does not contact in a glove box in an inert gas atmosphere. . Next, lithium, silicon, and carbon are weighed and put into a crucible. The crucible is further sealed in a sealed container having heat resistance. Remove the sealed container from the glove box and heat it using an electric furnace to make a melt. The heating temperature is not higher than the boiling point of lithium (1347 ° C.), preferably 700 ° C. to 1000 ° C. When the crucible in the sealed container is heated in an electric furnace, lithium is melted to form a lithium flux, and then silicon and carbon are dissolved in the lithium flux to obtain a silicon-carbon melt.
４Ｈ炭化珪素単結晶もしくは６Ｈ炭化珪素単結晶の種結晶基板を作製する工程は、２Ｈ
炭化珪素単結晶（膜）がＬＰＥ成長する種結晶基板の面を、Ｃ面［（０００−１）面］か
ら８度以下の面となる様に加工するものである。
The step of fabricating a 4H silicon carbide single crystal or 6H silicon carbide single crystal seed substrate is 2H
The surface of the seed crystal substrate on which the silicon carbide single crystal (film) grows by LPE is processed so as to be a surface of 8 degrees or less from the C plane [(000-1) plane].
種結晶基板のＣ面に２Ｈ炭化珪素単結晶をＬＰＥ成長させる工程は、種結晶基板を融液
に浸漬させて保持する工程、融液の温度を下げて２Ｈ炭化珪素単結晶を析出成長させる（
温度降下法）、もしくは融液に高温領域と低温領域を作り２Ｈ炭化珪素単結晶を析出成長
させる（温度勾配法）工程からなる。種結晶基板のＣ面と融液との接触時間は１〜１００
時間、好ましくは１０〜５０時間である。
The step of LPE growing the 2H silicon carbide single crystal on the C-plane of the seed crystal substrate is a step of immersing and holding the seed crystal substrate in the melt, and lowering the temperature of the melt to precipitate and grow the 2H silicon carbide single crystal (
A temperature drop method), or a step of forming a high temperature region and a low temperature region in the melt and precipitating and growing a 2H silicon carbide single crystal (temperature gradient method). The contact time between the C surface of the seed crystal substrate and the melt is 1 to 100.
Time, preferably 10 to 50 hours.
温度降下法で、種結晶基板のＣ面上に２Ｈ炭化珪素単結晶をＬＰＥ成長させるには、融
液温７００〜１０００℃で１〜１００時間保持した後、時間当たり０．１〜１００℃／Ｈ
ｒの一定速度で融液温を低下させる。６００〜８００℃まで融液温が下がったところで、
結晶成長を終了させる。その後、室温まで自然冷却して種結晶基板のＣ面に２Ｈ炭化珪素
単結晶が形成された炭化珪素単結晶基板を得る。成長初期段階で融液中の炭化珪素の過飽
和度を大きくして、種結晶基板が熔融するメルトバック現象を抑制するため、温度降下開
始時の融液温度の低下速度を大きくし、その後一定速度で融液温度を低下させるスーパー
冷却法（２段冷却法）を採用することもできる。
In order to grow 2H silicon carbide single crystal on the C-plane of the seed crystal substrate by the temperature drop method, the melt temperature is maintained at 700 to 1000 ° C. for 1 to 100 hours, and then 0.1 to 100 ° C./hour. H
The melt temperature is lowered at a constant rate of r. When the melt temperature falls to 600-800 ° C,
Terminate crystal growth. Thereafter, it is naturally cooled to room temperature to obtain a silicon carbide single crystal substrate having a 2H silicon carbide single crystal formed on the C-plane of the seed crystal substrate. In order to suppress the meltback phenomenon in which the seed crystal substrate melts by increasing the supersaturation degree of silicon carbide in the melt at the initial stage of growth, the rate of decrease in the melt temperature at the start of temperature drop is increased, and then a constant rate It is also possible to adopt a super cooling method (two-stage cooling method) that lowers the melt temperature.
温度勾配法で、種結晶基板のＣ面上に２Ｈ炭化珪素単結晶をＬＰＥ成長させるには、高
温領域の融液温度を８００℃以上とし、低温領域の融液温度を７００℃以上とし、高温領
域と低温領域の温度差を１０〜５００℃とする。坩堝の底部を高温領域に種結晶基板が融
液に接触する上部を低温領域とすることで、低温領域にある種結晶基板のＣ面に２Ｈ炭化
珪素単結晶を形成することができる。その後、室温まで自然冷却して種結晶基板のＣ面に
２Ｈ炭化珪素単結晶が形成された炭化珪素単結晶基板を得る。
In order to LPE grow a 2H silicon carbide single crystal on the C-plane of the seed crystal substrate by the temperature gradient method, the melt temperature in the high temperature region is set to 800 ° C. or higher, and the melt temperature in the low temperature region is set to 700 ° C. or higher. The temperature difference between the region and the low temperature region is 10 to 500 ° C. A 2H silicon carbide single crystal can be formed on the C-plane of the seed crystal substrate in the low temperature region by setting the bottom of the crucible to the high temperature region and the top where the seed crystal substrate contacts the melt as the low temperature region. Thereafter, it is naturally cooled to room temperature to obtain a silicon carbide single crystal substrate having a 2H silicon carbide single crystal formed on the C-plane of the seed crystal substrate.
冷却後炭化珪素単結晶基板取り出す工程は、密封容器を室温まで冷却した後電気炉から
密封容器を取り出し、次に密封容器から坩堝を取り出して、エタノールや水で残留リチウ
ム等を除去し、坩堝から２Ｈ炭化珪素単結晶が形成された種結晶基板とその他の珪素と炭
素の混合生成物を取り出す工程と、これら種結晶基板と混合生成物を塩酸で処理する工程
、Ｘ線回折装置等で生成された結晶を測定する工程を含むものである。
After cooling, the step of taking out the silicon carbide single crystal substrate is to cool the sealed container to room temperature, then remove the sealed container from the electric furnace, then remove the crucible from the sealed container, remove residual lithium etc. with ethanol or water, The seed crystal substrate on which the 2H silicon carbide single crystal is formed and the other step of taking out the mixed product of silicon and carbon, the step of treating the seed crystal substrate and the mixed product with hydrochloric acid, the X-ray diffractometer, etc. And a step of measuring the obtained crystals.
種結晶基板となる４Ｈもしくは６Ｈ炭化珪素単結晶のＣ面［（０００−１）面］に、２
Ｈ炭化珪素単結晶を低温度で３０μｍ以上の厚みでＬＰＥ成長させることができ、工業的
により効率的でより安定的により低コストで生産できるようになった。
On the C plane [(000-1) plane] of the 4H or 6H silicon carbide single crystal to be the seed crystal substrate, 2
The H silicon carbide single crystal can be grown by LPE at a low temperature at a thickness of 30 μm or more, and can be produced industrially more efficiently, more stably and at a lower cost.
以下本願発明を、図面を参照しながら実施例に基づいて詳細に説明する。 Hereinafter, the present invention will be described in detail based on examples with reference to the drawings.
図１に、用いた炭化珪素単結晶成長装置の概要で、抵抗加熱式の電気炉１５にステンレ
ス製の密封容器１４を設置した状態を示す。電気炉内で密封容器内の融液を加熱、保温、
冷却を行い炭化珪素単結晶を成長させた。
FIG. 1 shows an outline of the silicon carbide single crystal growth apparatus used, in which a stainless steel sealed
Cooling was performed to grow a silicon carbide single crystal.
アルゴンガス雰囲気下のグローブボックス内で、リチウム：珪素：炭素＝０．１６３：
０．０７５：０．１２４のモル比で秤量し、総量約４．７２（ｇ）をタングステン製の坩
堝１３に詰め、ステンレス製の密封容器１４の内底面に配した。純度９９．９％以上のリ
チウムと珪素、炭素を用いた。種結晶基板１１は、約１５ｍｍ×約１０ｍｍ×約０．４ｍ
ｍ厚の大きさの６Ｈ炭化珪素単結晶で、種結晶基板保持治具１６に取り付けた。融液と接
する面がＣ面［（０００−１）面］のジャスト面とした。
In a glove box under an argon gas atmosphere, lithium: silicon: carbon = 0.163:
Weighed at a molar ratio of 0.075: 0.124, a total amount of 4.72 (g) was packed in a
An m-thick 6H silicon carbide single crystal was attached to the seed crystal
密封された密封容器１４をグローブボックスより取り出し、電気炉１５内に密封容器１
４を設置した。電気炉１５の温度を上げ坩堝１２を９００℃としリチウムを融解させてリ
チウムフラックス作製した。リチウムフラックス中に珪素と炭素を熔解させるため９００
℃で２時間保持し珪素と炭素の融液を得た後、７００℃まで１０℃／時間の速度で融液の
温度を下げ、６Ｈ炭化珪素単結晶のＣ面［（０００−１）面］に２Ｈ炭化珪素単結晶を成
長させた。７００℃から室温までは炉冷した。
The sealed
4 was installed. The temperature of the
After obtaining a silicon and carbon melt at 2 ° C. for 2 hours, the melt temperature was lowered to 700 ° C. at a rate of 10 ° C./hour, and the C plane of the 6H silicon carbide single crystal [(000-1) plane] A 2H silicon carbide single crystal was grown. The furnace was cooled from 700 ° C. to room temperature.
室温迄冷却された密封容器１４を開け、坩堝１３を取り出した後エタノールと水を用い
て残留リチウムの除去処理を行い、坩堝から２Ｈ炭化珪素単結晶が形成された種結晶基板
とその他の珪素と炭素の混合生成物を取り出し、塩酸処理を行い炭化珪素単結晶基板を得
た。
The sealed
得られた炭化珪素単結晶基板の評価結果を、図２から図４に示す。図２は基板の断面と
表面のＳＥＭ写真、図３に基板のＸ線回折結果、図４に基板以外の混合生成物のＸ線回折
結果を示す。
The evaluation results of the obtained silicon carbide single crystal substrate are shown in FIGS. 2 shows a cross-sectional and surface SEM photograph of the substrate, FIG. 3 shows the X-ray diffraction result of the substrate, and FIG. 4 shows the X-ray diffraction result of the mixed product other than the substrate.
図２ａ）は、種結晶基板（６Ｈ炭化珪素単結晶）のＣ面側の断面部のＳＥＭ写真である
。図２ａ）の写真で、下向きの矢印領域が種結晶基板の６Ｈ炭化珪素単結晶で、上向きと
左向きの矢印で囲まれる領域が本実施例で得られた、約３３μｍ厚の２Ｈ炭化珪素単結晶
ＬＰＥ膜である。上向きと右向きの矢印で囲まれる領域は、２Ｈ炭化珪素単結晶ＬＰＥ膜
ではなく雑晶となっている。図２ｂ）は表面部のＳＥＭ写真である。図２ａ）と図２ｂ）
から、種結晶基板のＣ面側の一部分ではあるが、ＬＰＥ成長した２Ｈ炭化珪素単結晶の薄
膜が形成されていることが確認できた。該部分をＥＤＳ（Ｅｎｅｒｇｙ Ｄｉｓｐｅｒｓ
ｉｖｅ Ｘ−ｒａｙ Ｓｐｅｃｔｔｒｏｓｃｏｐｙ）で分析した結果（データは省略）、
珪素（Ｓｉ）と炭素（Ｃ）から形成されていることが確認できた。
FIG. 2 a) is an SEM photograph of the cross section on the C-plane side of the seed crystal substrate (6H silicon carbide single crystal). In the photograph of FIG. 2a), the downward arrow region is a 6H silicon carbide single crystal of the seed crystal substrate, and the region surrounded by the upward and leftward arrows is obtained in this example, and the 2H silicon carbide single crystal having a thickness of about 33 μm is obtained. LPE membrane. The region surrounded by the upward and rightward arrows is not a 2H silicon carbide single crystal LPE film but a miscellaneous crystal. FIG. 2b) is a SEM photograph of the surface portion. 2a) and 2b)
From this, it was confirmed that a thin film of 2H silicon carbide single crystal grown by LPE was formed, although it was a part of the C-plane side of the seed crystal substrate. The portion is divided into EDS (Energy Dispersers
ive X-ray Spectroscopy) (data not shown),
It was confirmed that the film was formed from silicon (Si) and carbon (C).
図３は、ＬＰＥ成長薄膜のＸ線回折結果である。用いた単結晶Ｘ線回折装置は、リガク
製Ｒ−ＡＸＩＳ ＲＡＰＩＤ２（２はローマ数字）である。種結晶基板の６Ｈ炭化珪素単
結晶の回折ピークは３５．７２４°で、ＬＰＥ薄膜の回折ピークは３５．６４３°と異な
った位置にあることが判る。
FIG. 3 is an X-ray diffraction result of the LPE grown thin film. The single crystal X-ray diffractometer used is R-AXIS RAPID2 (2 is a Roman numeral) manufactured by Rigaku. It can be seen that the diffraction peak of the 6H silicon carbide single crystal of the seed crystal substrate is 35.724 °, and the diffraction peak of the LPE thin film is at a position different from 35.643 °.
図４は、基板以外の混合生成物を、ω／２θでスキャンしたＸ線回折結果である。用い
た粉末Ｘ線回折装置は、リガク製ＲＩＮＴ２０００である。図４に示すように、強い２Ｈ
炭化珪素単結晶の回折ピークデータと、弱い３Ｃ炭化珪素単結晶の回折ピークデータが得
られた。
FIG. 4 is an X-ray diffraction result obtained by scanning a mixed product other than the substrate at ω / 2θ. The powder X-ray diffractometer used is RINT2000 manufactured by Rigaku. As shown in FIG. 4, strong 2H
Diffraction peak data of a silicon carbide single crystal and weak 3C silicon carbide single crystal were obtained.
図２から図４に示した結果から、種結晶基板である６Ｈ炭化珪素単結晶基板のＣ面に形
成されたＬＰＥ成長薄膜は、２Ｈ炭化珪素単結晶であると確認できた。
From the results shown in FIGS. 2 to 4, it was confirmed that the LPE grown thin film formed on the C-plane of the 6H silicon carbide single crystal substrate as the seed crystal substrate was a 2H silicon carbide single crystal.
本実施例は、融液の原料配合比と種結晶基板、炉内温度以外は実施例１と同じである。
アルゴンガス雰囲気下のグローブボックス内で、リチウム：珪素：炭素＝０．１４０：０
．０６０：０．０８０のモル比で秤量し、総量約３．６２（ｇ）をタングステン製の坩堝
１３に詰め、ステンレス製の密封容器１４の内底面に配した。純度９９．９％以上のリチ
ウムと珪素、炭素を用いた。種結晶基板１１は、約１５ｍｍ×約１０ｍｍ×約０．４ｍｍ
厚の大きさの４Ｈ炭化珪素単結晶で、種結晶基板保持治具に取り付けた。融液と接する面
がＣ面［（０００−１）面］のジャスト面とした。
This example is the same as Example 1 except for the raw material mixture ratio of the melt, the seed crystal substrate, and the furnace temperature.
In a glove box under an argon gas atmosphere, lithium: silicon: carbon = 0.140: 0
. A molar ratio of 060: 0.080 was weighed, and a total amount of 3.62 (g) was packed in a
A 4H silicon carbide single crystal having a large thickness was attached to a seed crystal substrate holding jig. The surface in contact with the melt was the just surface of the C surface [(000-1) surface].
密封容器１４を電気炉１５内に設置し、電気炉１５の温度を上げ坩堝１３を９２５℃に
加熱して、リチウムを融解させリチウムフラックスを作製した。リチウムフラックス中に
珪素と炭素を熔解させるため９２５℃で２時間保持し珪素と炭素の融液を得た。９２５℃
から９００℃までは１０℃／時間の速度で融液の温度を下げ、９００℃から７５０℃まで
は３℃／時間の速度で融液の温度を下げた後、７００℃から室温までは炉冷した。
The sealed
From 900 ° C. to 900 ° C., the temperature of the melt is lowered at a rate of 10 ° C./hour, from 900 ° C. to 750 ° C., the temperature of the melt is lowered at a rate of 3 ° C./hour, and then from 700 ° C. to room temperature is cooled in the furnace. did.
得られた炭化珪素単結晶基板の評価結果を、図５に示す。図５ａ）は種結晶基板（４Ｈ
炭化珪素単結晶）のＣ面側の断面部を４５度の角度から観察したＳＥＭ写真である。図５
ａ）の写真で、下向きの矢印領域が種結晶基板の４Ｈ炭化珪素単結晶で、上向きの矢印領
域が本実施例で得られた約３３μｍ厚の２Ｈ炭化珪素単結晶である。図５ｂ）は表面部の
ＳＥＭ写真である。実施例１と同様に、ＬＰＥ成長薄膜が形成されていることが判る。デ
ータは省略するが、Ｘ線回折結果からＬＰＥ成長薄膜は２Ｈ炭化珪素単結晶であることが
確認できた。
The evaluation result of the obtained silicon carbide single crystal substrate is shown in FIG. FIG. 5a) shows a seed crystal substrate (4H).
It is the SEM photograph which observed the cross-section part by the side of C side of (silicon carbide single crystal) from a 45-degree angle. FIG.
In the photograph a), the downward arrow region is a 4H silicon carbide single crystal of a seed crystal substrate, and the upward arrow region is a 2H silicon carbide single crystal of about 33 μm thickness obtained in this example. FIG. 5b) is an SEM photograph of the surface portion. It can be seen that an LPE-grown thin film is formed as in Example 1. Although the data is omitted, it was confirmed from the X-ray diffraction results that the LPE-grown thin film was a 2H silicon carbide single crystal.
本実施例は、種結晶基板のＣ面が８度のオフアングル面である以外は、実施例２と同じ
である。データは省略するが、種結晶基板のＣ面から８度のオフアングル面上に形成され
た、約５０μｍ厚のＬＰＥ成長薄膜は２Ｈ炭化珪素単結晶であることが確認できた。
This example is the same as Example 2 except that the C-plane of the seed crystal substrate is an off-angle plane of 8 degrees. Although data is omitted, it was confirmed that the LPE grown thin film of about 50 μm thickness formed on the off-angle plane of 8 degrees from the C plane of the seed crystal substrate was a 2H silicon carbide single crystal.
本実施例は、種結晶基板のＣ面角度と融液の原料配合比、炉内温度の冷却速度を変えた
ものである。アルゴンガス雰囲気下のグローブボックス内で、リチウム：珪素：炭素＝０
．３５：０．２０：０．２０のモル比で秤量し、総量約１０．４（ｇ）をタングステン製
の坩堝１３に詰め、ステンレス製の密封容器１４の内底面に配した。純度９９．９％以上
のリチウムと珪素、炭素を用いた。種結晶基板１１は、約１５ｍｍ×約１０ｍｍ×約０．
４ｍｍ厚の大きさの４Ｈ炭化珪素単結晶で、種結晶基板保持治具に取り付けた。融液と接
する面がＣ面［（０００−１）面］のジャスト面とした。密封容器１４を電気炉１５内に
設置し、電気炉１５の温度を上げ坩堝１３を９２５℃に加熱して、リチウムを融解させリ
チウムフラックスを作製した。リチウムフラックス中に珪素と炭素を熔解させるため９２
５℃で２時間保持し珪素と炭素の融液を得た。９２５℃から９００℃までは５℃／時間の
速度で融液の温度を下げ、９００℃から７５０℃までは３℃／時間の速度で融液の温度を
下げた後、７００℃から室温までは炉冷した。データは省略するが、種結晶基板のＣ面上
に形成された、約７０μｍ厚のＬＰＥ成長薄膜は２Ｈ炭化珪素単結晶であることが確認で
きた。
In the present embodiment, the C-plane angle of the seed crystal substrate, the raw material blending ratio of the melt, and the cooling rate of the furnace temperature are changed. Lithium: silicon: carbon = 0 in a glove box under an argon gas atmosphere
. A molar ratio of 35: 0.20: 0.20 was weighed, and a total amount of about 10.4 (g) was packed in a
A 4H silicon carbide single crystal having a thickness of 4 mm was attached to a seed crystal substrate holding jig. The surface in contact with the melt was the just surface of the C surface [(000-1) surface]. The sealed
The mixture was kept at 5 ° C. for 2 hours to obtain a silicon-carbon melt. The temperature of the melt is lowered at a rate of 5 ° C./hour from 925 ° C. to 900 ° C., the temperature of the melt is lowered at a rate of 3 ° C./hour from 900 ° C. to 750 ° C., and then from 700 ° C. to room temperature. The furnace was cooled. Although data is omitted, it was confirmed that the LPE grown thin film with a thickness of about 70 μm formed on the C-plane of the seed crystal substrate was a 2H silicon carbide single crystal.
１１ 種結晶基板、１２ 融液、
１３ 坩堝、１４ 密封容器、
１５ 電気炉、１６ 種結晶基板保持治具。
11 seed crystal substrate, 12 melt,
13 crucibles, 14 sealed containers,
15 Electric furnace, 16 seed crystal substrate holding jig.
Claims (5)
炭化珪素単結晶が形成されたことを特徴とする炭化珪素単結晶基板。 2H silicon carbide single crystal or 6H silicon carbide single crystal C plane [(000-1) plane]
A silicon carbide single crystal substrate in which a silicon carbide single crystal is formed.
、８度以下であることを特徴とする請求項１に記載の炭化珪素単結晶基板。 2. The silicon carbide single crystal substrate according to claim 1, wherein the inclination of the C plane [(000-1) plane] of the 4H silicon carbide single crystal or 6H silicon carbide single crystal is 8 degrees or less.
る請求項１に記載の炭化珪素単結晶基板。 2. The silicon carbide single crystal substrate according to claim 1, wherein the 2H silicon carbide single crystal is an LPE film epitaxially grown in a liquid phase.
項１もしくは３に記載の炭化珪素単結晶基板。 4. The silicon carbide single crystal substrate according to claim 1, wherein the 2H silicon carbide single crystal has a thickness (LPE film thickness) of 30 μm or more. 5.
素単結晶の種結晶基板を作製する工程、秤量した原料と種結晶基板を坩堝に入れ、坩堝を
密封容器に密封する工程、密封容器を加熱しリチウムフラックス中で珪素と炭素の融液を
作製する工程、種結晶基板のＣ面［（０００−１）面］に２Ｈ炭化珪素単結晶をＬＰＥ成
長させる工程、密封容器冷却後炭化珪素単結晶基板取り出す工程を有することを特徴とす
る炭化珪素単結晶基板の製造方法。 A step of weighing lithium, silicon, and carbon raw materials, a step of preparing a 4H silicon carbide single crystal or 6H silicon carbide single crystal seed crystal substrate, placing the weighed raw material and seed crystal substrate in a crucible, and sealing the crucible in a sealed container A step of heating a sealed container to produce a silicon-carbon melt in lithium flux, a step of LPE growing a 2H silicon carbide single crystal on the C-plane [(000-1) plane] of the seed crystal substrate, sealing A method for producing a silicon carbide single crystal substrate comprising a step of taking out a silicon carbide single crystal substrate after cooling the container.
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|---|---|---|---|---|
| JP2000001398A (en) * | 1998-06-09 | 2000-01-07 | Fuji Electric Co Ltd | Production of silicon carbide semiconductor substrate |
| JP2003282451A (en) * | 2002-03-22 | 2003-10-03 | National Institute Of Advanced Industrial & Technology | METHOD OF FORMATION SiC MONOCRYSTALLINE THIN FILM |
| WO2006070749A1 (en) * | 2004-12-28 | 2006-07-06 | Matsushita Electric Industrial Co., Ltd. | METHOD FOR PRODUCING SILICON CARBIDE (SiC) SINGLE CRYSTAL AND SILICON CARBIDE (SiC) SINGLE CRYSTAL OBTAINED BY SUCH METHOD |
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| JP2000001398A (en) * | 1998-06-09 | 2000-01-07 | Fuji Electric Co Ltd | Production of silicon carbide semiconductor substrate |
| JP2003282451A (en) * | 2002-03-22 | 2003-10-03 | National Institute Of Advanced Industrial & Technology | METHOD OF FORMATION SiC MONOCRYSTALLINE THIN FILM |
| WO2006070749A1 (en) * | 2004-12-28 | 2006-07-06 | Matsushita Electric Industrial Co., Ltd. | METHOD FOR PRODUCING SILICON CARBIDE (SiC) SINGLE CRYSTAL AND SILICON CARBIDE (SiC) SINGLE CRYSTAL OBTAINED BY SUCH METHOD |
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