JP2580523B2 - Growth method of titanium diboride single crystal - Google Patents
Growth method of titanium diboride single crystalInfo
- Publication number
- JP2580523B2 JP2580523B2 JP5301310A JP30131093A JP2580523B2 JP 2580523 B2 JP2580523 B2 JP 2580523B2 JP 5301310 A JP5301310 A JP 5301310A JP 30131093 A JP30131093 A JP 30131093A JP 2580523 B2 JP2580523 B2 JP 2580523B2
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- Prior art keywords
- single crystal
- growth
- titanium diboride
- crystal
- titanium
- Prior art date
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、フローティング・ゾー
ン(ＦＺ)法による二ホウ化チタン単結晶の育成法に関す
る。The present invention relates to a method for growing a titanium diboride single crystal by a floating zone (FZ) method.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】二ホウ
化チタンは、現在、高温構造材や複合体の強化材として
の利用が検討されている。その単結晶の利用としては、
融点が高く、仕事関数及び蒸気圧が低いことから、長寿
命・高輝度電子放射材料として期待されている。この利
用には、純度の高い高品質大型単結晶が必要である。BACKGROUND OF THE INVENTION Titanium diboride is currently being studied for use as a reinforcing material for high temperature structural materials and composites. Use of the single crystal
Because of its high melting point, low work function and low vapor pressure, it is expected to be a long-life, high-brightness electron-emitting material. For this use, a high-quality large single crystal with high purity is required.
【０００３】高純度な二ホウ化チタン単結晶の育成法と
しては、育成温度が高く、不純物が蒸発により除去され
るＦＺ法が適している。しかしながら、融点における蒸
気圧が高いことから、安定な融帯移動による育成が行わ
れておらず、試料は多結晶化しているのが実情である。As a method for growing a high-purity titanium diboride single crystal, the FZ method in which a growing temperature is high and impurities are removed by evaporation is suitable. However, since the vapor pressure at the melting point is high, growth by stable movement of the melt zone has not been performed, and the fact is that the sample is polycrystalline.
【０００４】本発明は、上記従来技術の欠点を解消し、
再現性良く欠陥の少ない良質な大型二ホウ化チタン単結
晶を得る方法を提供することを目的とするものである。[0004] The present invention overcomes the above-mentioned disadvantages of the prior art,
It is an object of the present invention to provide a method for obtaining a large-sized titanium diboride single crystal with good reproducibility and few defects.
【０００５】[0005]
【課題を解決するための手段】前記課題を解決するた
め、本発明者らは、従来のＦＺ法による二ホウ化チタン
単結晶育成における育成上の問題点を調べた結果、次の
ことが判明した。In order to solve the above-mentioned problems, the present inventors have investigated the problems in the growth of titanium diboride single crystals by the conventional FZ method, and found the following. did.
【０００６】すなわち、二ホウ化チタン単結晶の育成温
度が２７９０℃と高く、蒸発が非常に激しく、その速度
は、例えば炭化チタン結晶の育成に比較すると約４０倍
激しいため、その蒸発物がワークコイルに付着し放電を
引き起こすこと、及び蒸発物が成長した結晶表面に付着
し、その部分から針状結晶が成長し、ヒートシンクとな
ることで単結晶化を阻害していることが判明した。That is, the growth temperature of a titanium diboride single crystal is as high as 2790 ° C., and the evaporation is very intense. The rate of the evaporation is about 40 times as intense as, for example, the growth of a titanium carbide crystal. It was found that they adhered to the coil to cause a discharge, and that the evaporates adhered to the grown crystal surface, and needle-like crystals grew from that portion, acting as a heat sink, thereby inhibiting single crystallization.
【０００７】そこで、結晶育成時の蒸発による問題を解
消するように、育成条件を検討した結果、蒸発速度は、
雰囲気圧を上げることにより抑制することが可能で、ま
た、育成速度を高速とすることで相対的に蒸発速度を下
げることができ、良質な二ホウ化チタン単結晶が得られ
ることが確認された。同時に、融帯組成を、Ｂ（ホウ
素）とＴｉ（チタン）との比（Ｂ／Ｔｉ）で２．１〜
３．１の範囲内となるように制御することで、育成温度
を下げることもでき、チタンの蒸発が抑制され、良質の
二ホウ化チタン単結晶を再現性よく育成することができ
ることが確認された。本発明は、これらの知見に基づい
て完成されたものである。 Therefore, the problem of evaporation during crystal growth is solved.
As to consumption, as a result of considering the growth conditions, the rate of evaporation,
It can be suppressed by increasing the atmospheric pressure, or
In addition , it was confirmed that the evaporation rate could be relatively reduced by increasing the growth rate, and that a high-quality titanium diboride single crystal was obtained. At the same time, the melt zone composition was changed to B (Ho
Element) and Ti (titanium) in a ratio (B / Ti) of 2.1 to
The growth temperature is controlled by controlling the temperature to be within the range of 3.1.
Can be reduced , titanium evaporation is suppressed, and high quality
Titanium diboride single crystal can be grown with good reproducibility
Was confirmed. The present invention is based on these findings.
It was completed.
【０００８】すなわち、本発明は、フローティング・ゾ
ーン法により二ホウ化チタン単結晶を育成するに当たっ
て、雰囲気ガス圧を５気圧以上３０気圧以下とし、融帯
組成が、Ｂ（ホウ素）とＴｉ（チタン）との比（Ｂ／Ｔ
ｉ）で２．１〜３．１の範囲内となるようにして、育成
速度３〜１２ｃｍ／ｈで育成することを特徴とする良質
二ホウ化チタン単結晶の育成法を要旨としている。[0008] That is, the present invention is, hit the fostering titanium diboride single crystal by the floating zone method
Te, not more than 30 atm or more 5 atm atmospheric gas pressure, the melt zone
The composition has a ratio of B (boron) to Ti (titanium) (B / T
i) be kept within the range of 2.1 to 3.1 in, and the gist of the growth method of quality titanium diboride single crystal, characterized by growing at a growth rate 3~12cm / h.
【０００９】[0009]
【作用】以下に本発明を更に詳細に説明する。The present invention will be described below in more detail.
【００１０】まず、本発明において用いられる装置の一
例を図１に示す。図中、１と１′はそれぞれ上軸と下軸
の駆動部、２と２′はそれぞれ上軸と下軸、３と３′は
ホルダー、４はワークコイル、５は原料焼結棒、６は融
帯、７は単結晶、８は種結晶又は初期融帯形成用の焼結
棒である。First, FIG. 1 shows an example of an apparatus used in the present invention. In the figure, 1 and 1 'are the driving parts of the upper and lower shafts respectively, 2 and 2' are the upper and lower shafts respectively, 3 and 3 'are holders, 4 is a work coil, 5 is a raw material sintered rod, 6 Is a fusion zone, 7 is a single crystal, 8 is a seed crystal or a sintered rod for forming an initial fusion zone.
【００１１】試料の加熱は、ワークコイル４に高周波電
流を流すことにより、試料に誘導電流を生じさせ、その
ジュール熱により行う。このようにして、形成された融
帯６に上方より原料棒５を送り込み、下方より単結晶７
を育成する。The sample is heated by applying a high-frequency current to the work coil 4 to generate an induced current in the sample and using the Joule heat. The raw material rod 5 is fed from above into the melt zone 6 thus formed, and the single crystal 7 from below.
Nurture.
【００１２】次に本発明による単結晶育成の手順を示
す。まず、原料の二ホウ化チタン粉末とホウ素粉末(又
はチタン金属粉末)を所定比によく混合後、結合剤とし
て少量の樟脳を加え、ラバープレス(２０００kg／cm2)
により圧粉棒を作製する。この圧粉棒を真空中又は不活
性ガス中で千数百℃に加熱し、原料焼結棒を作製する。Next, the procedure for growing a single crystal according to the present invention will be described. First, after mixing titanium diboride powder and boron powder (or titanium metal powder) as raw materials in a predetermined ratio, a small amount of camphor is added as a binder, and a rubber press (2000 kg / cm 2 )
To produce a compacting rod. This powder bar is heated in vacuum or an inert gas to one hundred and several hundred degrees Celsius to produce a raw material sintered bar.
【００１３】得られた焼結棒５を上軸２にホルダー３を
介してセットし、下軸２′には種結晶(又は初期融帯形
成用の焼結棒)８をホルダーを介してセットする。両者
の５と８の間に初期融帯の組成を制御するためのホウ素
焼結体(又はチタン金属円盤)を挾む。次にホウ素焼結体
(又はチタン金属円盤)とその周辺を加熱により溶融さ
せ、融帯６を形成させ、上軸２と下軸２′を下方に移動
させて単結晶７を育成する。The obtained sintered rod 5 is set on the upper shaft 2 via the holder 3, and a seed crystal (or a sintered rod for forming an initial melt zone) 8 is set on the lower shaft 2 ′ via the holder. I do. A boron sintered body (or a titanium metal disk) for controlling the composition of the initial zone is sandwiched between 5 and 8 of the two. Next, the boron sintered body
(Or a titanium metal disk) and its periphery are melted by heating to form a fusion zone 6, and the upper shaft 2 and the lower shaft 2 'are moved downward to grow a single crystal 7.
【００１４】このとき、下軸２′の移動速度、すなわ
ち、結晶育成速度は、育成中常に一定に保持する。その
移動速度範囲は３〜１２cm／hとする必要がある。好ま
しくは、６cm／h以上９cm／h以下である。この育成速度
により相対的に蒸発速度を下げることができる。At this time, the moving speed of the lower shaft 2 ', that is, the crystal growing speed is kept constant during the growing. The moving speed range must be 3 to 12 cm / h. Preferably, it is 6 cm / h or more and 9 cm / h or less. With this growth rate, the evaporation rate can be relatively reduced.
【００１５】育成速度と結晶性の関係を、ヘリウム雰囲
気圧１１気圧の下で定比組成の原料棒を用いて調べた。
その結果、３cm／h以下の育成速度では結晶表面に針状
結晶が成長し安定な融帯移動(育成)が行えなかった。せ
いぜい２cmの結晶が得られる程度であった。一方、１２
cm以上の育成速度では結晶に粒界が多数入り、単結晶と
はならなかった。したがって、育成速度は３〜１２cm／
hとし、６〜９cm/ｈが再現性が良く好ましい速度であ
る。The relationship between the growth rate and the crystallinity was examined using a raw material rod having a stoichiometric composition under a helium atmosphere pressure of 11 atm.
As a result, at a growth rate of 3 cm / h or less, needle-like crystals grew on the crystal surface, and stable fusion zone movement (growth) could not be performed. At most 2 cm of crystals could be obtained. On the other hand, 12
At a growth rate of cm or more, the crystal had many grain boundaries and did not become a single crystal. Therefore, the growth speed is 3 to 12 cm /
As h, 6 to 9 cm / h is a preferable speed with good reproducibility.
【００１６】上軸２の移動速度、すなわち、原料棒の融
帯への供給速度は、原料棒の密度が低いので、それを補
償して原料棒とほぼ同じ直径をもつ単結晶が育成される
ように設定する。The moving speed of the upper shaft 2, that is, the feeding speed of the raw material rods to the fusible zone is low, so that the density of the raw material rods is compensated, and a single crystal having substantially the same diameter as the raw material rods is grown. Set as follows.
【００１７】雰囲気としては、この結晶の育成では放電
が起こり易いので、イオン化ポテンシャルの最も大きい
ヘリウムガスを用いるのが好ましい。これは、高周波ワ
ークコイル部分で発生する放電を防止するためである。
アルゴンガスも可能である。更に蒸発速度は、雰囲気圧
の−０.７乗に比例するので、通常の雰囲気圧である数
気圧より高く設定することが肝要である。As an atmosphere, it is preferable to use a helium gas having the highest ionization potential because discharge is likely to occur in the growth of the crystal. This is to prevent discharge generated in the high-frequency work coil portion.
Argon gas is also possible. Further, since the evaporation rate is proportional to the atmosphere pressure to the power of -0.7, it is important to set the evaporation rate higher than the normal atmosphere pressure, which is several atmospheres.
【００１８】すなわち、育成する結晶の長さにも依存す
るが、安定に５〜６cmの結晶を育成するには、５気圧程
度でも可能ではあるが、１０気圧以上の圧力が好まし
い。一方、３０気圧以上では結晶に粒界が入り結晶性が
低下するので、雰囲気圧は５〜３０気圧の範囲とする。
雰囲気圧の制御により蒸発速度を１／３から２／３に抑
制することができる。That is, although it depends on the length of the crystal to be grown, it is possible to stably grow a crystal of 5 to 6 cm at a pressure of about 5 atm, but a pressure of 10 atm or more is preferable. On the other hand, if the pressure is 30 atm or more, grain boundaries enter the crystal and the crystallinity deteriorates. Therefore, the atmospheric pressure is in the range of 5 to 30 atm.
By controlling the atmospheric pressure, the evaporation rate can be suppressed from 1/3 to 2/3.
【００１９】原料については、蒸発速度を相対的に低下
させるために、育成速度を高くすることから、単結晶化
が容易なように、高純度原料を使用するのが好ましい。
特に、タングステンのような蒸気圧の低い不純物を含ま
ない原料を使用するのが好ましい。蒸気圧の高い不純物
は、多量に含まれない限り、育成時に、蒸発により完全
に除去され、育成に障害を与えることはない。[0019] The starting material, in order to relatively decrease the rate of evaporation, since increasing the growth rate, as single crystallization is easy, it is preferable to use high purity materials.
In particular, it is preferable to use a raw material that does not contain impurities having a low vapor pressure, such as tungsten. High vapor pressure impurities, unless contained in a large amount, at the time of development, is completely removed by evaporation, not Rukoto harm to development.
【００２０】更に、融帯組成の結晶性への影響を調べ
た。定比組成を持つ原料棒を用いると、育成中定比組成
より少しチタン過剰な組成で蒸発するので、融帯組成
(Ｂ／Ｔi原子比)は常に２.３(±０.１)になった。すな
わち、この組成(Ｂ／Ｔi＝２.３)の融液より蒸発する蒸
発物は定比組成(Ｂ／Ｔi＝２)となっていた。Further, the influence of the melt zone composition on the crystallinity was examined. When a raw material rod having a stoichiometric composition is used, it evaporates with a titanium excess composition during the growth, so
(B / Ti atomic ratio) was always 2.3 (± 0.1). That is, the evaporant evaporating from the melt having this composition (B / Ti = 2.3) had a stoichiometric composition (B / Ti = 2).
【００２１】融帯組成は、原料棒の組成で制御する。融
帯組成をよりホウ素過剰(Ｂ／Ｔi＞２.３)にすると育成
温度(加熱電力)が下がり、再現性よく良質な結晶が得ら
れる。しかしながら、融帯組成がＢ／Ｔi＝３.１になる
と、融帯直上に形成される傘状のものが大きくなり(ワ
ークコイルを原料棒が通過しなくなり)育成が困難にな
る。その際の原料焼結棒の組成(原子比Ｂ／Ｔi)は２.２
である。The composition of the melt zone is controlled by the composition of the raw material rod. When the melt zone composition is made more boron-excess (B / Ti> 2.3), the growth temperature (heating power) decreases, and a good-quality crystal with good reproducibility can be obtained. However, when the composition of the melt zone is B / Ti = 3.1, the umbrella-shaped material formed immediately above the melt zone becomes large (the raw material rod does not pass through the work coil), and it becomes difficult to grow. At that time, the composition (atomic ratio B / Ti) of the raw material sintered rod was 2.2.
It is.
【００２２】一方、原料棒組成をチタン過剰（Ｂ／Ｔｉ
＜２）とし、融帯組成をより定比に近付ける（すなわ
ち、Ｂ／Ｔｉ＜２．３）と、育成温度が高くなり、チタ
ンの蒸発が増加するため、育成上好ましくない。融帯組
成がＢ／Ｔｉ＜２．１の領域では、良質結晶育成の再現
性が悪い。したがって、融帯組成は、Ｂ／Ｔｉ＝２．１
〜３．１とする。On the other hand, if the composition of the raw material rod is excessive titanium (B / Ti
If the melt zone composition is set closer to the constant ratio (that is, B / Ti <2.3), the growth temperature increases , and the evaporation of titanium increases, which is not preferable for growth. In the region where the melt zone composition is B / Ti <2.1, the reproducibility of growing good quality crystals is poor. Therefore, the melt zone composition is B / Ti = 2.1
To 3.1 .
【００２３】次に本発明の実施例を示す。Next, an embodiment of the present invention will be described.
【００２４】市販の二ホウ化チタン粉末に結合剤として
樟脳を少量加え、直径１０mmのゴム袋に詰め円柱形にし
た。これを２０００kg／cm2のラバープレスを行い圧粉
体を得た。この圧粉体を真空中、１８００℃で加熱し、
直径９mm、長さ１２cm程度の焼結棒を得た。密度は約５
８％であった。A small amount of camphor was added as a binder to commercially available titanium diboride powder, and the mixture was packed in a rubber bag having a diameter of 10 mm to form a cylinder. This was subjected to a rubber press of 2000 kg / cm 2 to obtain a green compact. This green compact is heated at 1800 ° C. in vacuum,
A sintered rod having a diameter of 9 mm and a length of about 12 cm was obtained. The density is about 5
8%.
【００２５】この焼結棒を図１に示すＦＺ育成炉の上軸
にホルダーを介して固定し、下軸には二ホウ化チタン焼
結体を固定した。両者の間に０.１g程度のホウ素焼結体
を挾み、融帯組成を制御した。育成炉に７気圧のアルゴ
ンを充填した後、高周波コイル(内径１６mm、３巻２段)
によりホウ素焼結体とその周辺部を溶かし初期融帯を形
成し、９cm／hの育成速度で下方に移動させ、全長６c
m、直径０.９cmの単結晶を育成した。融帯組成はＢ／Ｔ
i＝２.３であった。This sintered rod was fixed to the upper shaft of the FZ growth furnace shown in FIG. 1 via a holder, and the titanium diboride sintered body was fixed to the lower shaft. About 0.1 g of a boron sintered body was sandwiched between the two to control the melt zone composition. After filling the growth furnace with 7 atmospheres of argon, a high-frequency coil (inner diameter 16 mm, 3 turns, 2 stages)
Melts the boron sintered body and its surroundings to form an initial melt zone, and moves downward at a growth rate of 9 cm / h to obtain a total length of 6 c
A single crystal having a diameter of 0.9 cm and a diameter of 0.9 cm was grown. Melt zone composition is B / T
i = 2.3.
【００２６】単結晶の粒界密度については、結晶棒終端
部から(１０１０)面を切り出し、鏡面研磨の後、エッチ
ング(硝酸：塩酸＝１：３の液で１分程度)して測定し
た。その結果、結晶は厚さ１mmの多結晶の皮で囲まれる
が、その中に粒界は全く含まない良質な単結晶であっ
た。The grain boundary density of the single crystal was measured by cutting out the (1010) plane from the end of the crystal rod, polishing it to a mirror surface, and etching (about 1 minute with a liquid of nitric acid: hydrochloric acid = 1: 3). As a result, the crystal was a high-quality single crystal surrounded by a 1 mm-thick polycrystalline skin, but without any grain boundaries.
【００２７】[0027]
【発明の効果】以上説明したように、本発明によれば、
亜粒界を含まない良質な大型二ホウ化チタン単結晶が得
られる。As described above, according to the present invention,
A high-quality large titanium diboride single crystal containing no subgrain boundaries can be obtained.
【図１】本発明に用いられる単結晶育成装置の一例を示
す説明図である。FIG. 1 is an explanatory view showing an example of a single crystal growing apparatus used in the present invention.
１ 上軸駆動部 １′ 下軸駆動部 ２ 上軸 ２′ 下軸 ３ ホルダー ３′ ホルダー ４ ワークコイル ５ 原料焼結棒 ６ 融帯 ７ 単結晶 ８ 種結晶又は初期融帯形成用の焼結棒 DESCRIPTION OF SYMBOLS 1 Upper shaft drive part 1 'Lower shaft drive part 2 Upper shaft 2' Lower shaft 3 Holder 3 'Holder 4 Work coil 5 Raw material sintering rod 6 Fusion zone 7 Single crystal 8 Seed crystal or sintering rod for initial fusion zone formation
Claims (2)
化チタン単結晶を育成するに当たって、雰囲気ガス圧を
５気圧以上３０気圧以下とし、融帯組成が、Ｂ（ホウ
素）とＴｉ（チタン）との比（Ｂ／Ｔｉ）で２．１〜
３．１の範囲内となるようにして、育成速度３〜１２ｃ
ｍ／ｈで育成することを特徴とする良質二ホウ化チタン
単結晶の育成法。1. A against the growing titanium diboride single crystal by the floating zone method, the ambient gas pressure of less than 5 atm 30 atm, is melt zone composition, B (Hou
Element) and Ti (titanium) in a ratio (B / Ti) of 2.1 to
3.1 so that the growth rate is 3 to 12c.
growth method of quality titanium diboride single crystal, characterized by growing at m / h.
ウムガスを用いる請求項１に記載の方法。2. The method according to claim 1, wherein an argon gas or a helium gas is used as the atmosphere gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5301310A JP2580523B2 (en) | 1993-11-05 | 1993-11-05 | Growth method of titanium diboride single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5301310A JP2580523B2 (en) | 1993-11-05 | 1993-11-05 | Growth method of titanium diboride single crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0891995A JPH0891995A (en) | 1996-04-09 |
| JP2580523B2 true JP2580523B2 (en) | 1997-02-12 |
Family
ID=17895314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5301310A Expired - Lifetime JP2580523B2 (en) | 1993-11-05 | 1993-11-05 | Growth method of titanium diboride single crystal |
Country Status (1)
| Country | Link |
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| JP (1) | JP2580523B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4515674B2 (en) * | 2001-09-11 | 2010-08-04 | 独立行政法人物質・材料研究機構 | Boride single crystal and substrate for semiconductor formation |
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1993
- 1993-11-05 JP JP5301310A patent/JP2580523B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
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| JPH0891995A (en) | 1996-04-09 |
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