JPH0489398A - Production of lithium niobate single crystal - Google Patents
Production of lithium niobate single crystalInfo
- Publication number
- JPH0489398A JPH0489398A JP20089490A JP20089490A JPH0489398A JP H0489398 A JPH0489398 A JP H0489398A JP 20089490 A JP20089490 A JP 20089490A JP 20089490 A JP20089490 A JP 20089490A JP H0489398 A JPH0489398 A JP H0489398A
- Authority
- JP
- Japan
- Prior art keywords
- melt
- crystal
- single crystal
- crystal growth
- composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 103
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000000155 melt Substances 0.000 claims abstract description 43
- 230000012010 growth Effects 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 16
- XUCJHNOBJLKZNU-UHFFFAOYSA-M dilithium;hydroxide Chemical group [Li+].[Li+].[OH-] XUCJHNOBJLKZNU-UHFFFAOYSA-M 0.000 claims description 3
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 2
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Chemical compound O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 abstract description 11
- 239000011248 coating agent Substances 0.000 abstract 1
- 238000000576 coating method Methods 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 description 5
- 239000010955 niobium Substances 0.000 description 5
- 238000010587 phase diagram Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000004781 supercooling Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 229910019704 Nb2O Inorganic materials 0.000 description 2
- 230000010261 cell growth Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- 229910008641 Li2O—Nb2O5 Inorganic materials 0.000 description 1
- 229910003327 LiNbO3 Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、結晶成分近傍の組成を有する融液に浸した種
結晶の所定面に単結晶を育成させる単結晶の製造方法に
関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a single crystal in which a single crystal is grown on a predetermined surface of a seed crystal immersed in a melt having a composition close to that of the crystal components.
［従来の方法］
従来の単結晶を製造する方法としては、例えばＣ２法（
チョクラルスキー法）が知られている。この方法は、結
晶成分融液に浸した種結晶の所定面に単結晶を育成させ
つつ単結晶を引き上げる方法である。[Conventional method] As a conventional method for producing single crystals, for example, the C2 method (
Czochralski method) is known. This method is a method of pulling a single crystal while growing it on a predetermined surface of a seed crystal immersed in a crystal component melt.
ニオブ酸リチウムの状態図を第２図（Ｌｉ０２− Ｎｂ
２Ｏ５系；Ｊ、Ａｐｐｌ、Ｐｈｙｓ、４２．５ （１９
７１） Ｊ、Ｒ，Ｃａｒｒｕｔｈｅｒｓ ｅｔ ａｌ。Figure 2 shows the phase diagram of lithium niobate (Li02-Nb
2O5 system; J, Appl, Phys, 42.5 (19
71) J, R, Carruthers et al.
）及び第３ ｑ （ＬｉＣＯ３−Ｎｂ２Ｏ５系； Ｊ、
Ｃｒｙｓ、 Ｇｒｏｗ、 ３．４゜（１９６８） Ｐ
、 Ｌｅｎｎｅｒ ｅｔ ａｌ、 ）に示す。) and 3rd q (LiCO3-Nb2O5 system; J,
Crys, Grow, 3.4° (1968) P
, Lenner et al. ).
従来、育成されているニオブ酸リチウムは第２図中Ａ点
近傍の帯−溶融する組成のものである。この場合、秤量
ミスあるいは不純物汚染による組成的適冷のみ考慮すれ
ばよく、育成速度５０ｇ ／時間以上での育成が可能で
ある。Conventionally grown lithium niobate has a composition that melts in the band near point A in FIG. In this case, only compositional cooling due to weighing errors or impurity contamination needs to be taken into consideration, and growth at a growth rate of 50 g/hour or more is possible.
この組成は化学量論組成ＬｉＯ２，Ｎｂ２Ｏ５（モル比
）［第２図中Ｂ点］とは異なり、ニオブ（Ｎｂ）過剰型
となっている。そのためリチウム（Ｌｉ）原子があるべ
き格子点にＮｂが存在したり、空格子点が存在したりす
る等の格子欠陥がおこり、物理化学的緒特性の不安定性
が問題となっているため化学量論組成の単結晶の製造が
強く望まれている。This composition is different from the stoichiometric composition LiO2, Nb2O5 (molar ratio) [point B in FIG. 2], and has an excess of niobium (Nb). As a result, lattice defects such as the presence of Nb or the presence of vacancies occur at lattice points where lithium (Li) atoms should exist, resulting in instability of physicochemical properties, resulting in stoichiometric There is a strong desire to produce single crystals with a theoretical composition.
化学量論組成の単結晶を育成するためには一１第２図と
して示した状態図より明らかなように融液組成がＬ１２
０ Ｎｂ２０５＝ ５８ ：４２ （モル比）である融
液（第２図Ｃ点）からの育成が必要となる。In order to grow a single crystal with a stoichiometric composition, the melt composition must be L12, as is clear from the phase diagram shown in Figure 2.
It is necessary to grow from a melt (point C in Fig. 2) with a molar ratio of 0 Nb205 = 58:42.
［発明が解決しようとする課題］
通常のＣ２法に従ってこの融液から結晶を育成すると、
融液組成は晶析率あるいは温度降下に従って徐々にＬｉ
過剰になり、結晶組成もそれに伴ない液相線勾配および
固相線勾配に従ってＬｉ過剰になる。[Problem to be solved by the invention] When crystals are grown from this melt according to the usual C2 method,
The melt composition gradually changes depending on the crystallization rate or temperature drop.
Li becomes excessive, and the crystal composition also becomes excessive according to the liquidus gradient and solidus gradient.
それを抑制するためには、融液組成が変わらないように
Ｎｂ過剰の結晶原料を補給する必要がある。In order to suppress this, it is necessary to replenish the crystal raw material with excess Nb so that the melt composition does not change.
また、融液組成と育成結晶組成とが大きく異なっている
ため、組成的過冷却が発生し易く、高品質な単結晶を得
ることは難しい。Furthermore, since the melt composition and the grown crystal composition are significantly different, compositional supercooling is likely to occur, making it difficult to obtain a high-quality single crystal.
組成的過冷却の発生を防ぐためには、結晶育成速度を遅
くする、融液界面の温度勾配を大きくする、融液界面の
結晶成長速度のミクロ的な変動を抑える等の手段が考え
られるが、例えば、融液界面の温度勾配を大きくすると
結晶にクラックが生じ易く、高品質な単結晶を得ること
は難しい。In order to prevent the occurrence of compositional supercooling, measures such as slowing the crystal growth rate, increasing the temperature gradient at the melt interface, and suppressing microscopic fluctuations in the crystal growth rate at the melt interface can be considered. For example, if the temperature gradient at the melt interface is increased, cracks are likely to occur in the crystal, making it difficult to obtain a high-quality single crystal.
［課題を解決するための手段１
本発明者は、化学量論組成近傍のニオブ酸リチウムの単
結晶を引き上げ法で製造する方法について鋭意検討した
結果、るつぼの周囲を特定の融液で包囲し、特定の初期
融液組成、結晶育成速度及び融液界面の温度勾配を選択
することにより、結晶育成融液を補給することなく、ク
ラックの発生および組成変動のほとんどない高品質の単
結晶が得られることを見出し、本発明に到達した。[Means for Solving the Problems 1] As a result of intensive study on a method for producing a single crystal of lithium niobate with a near stoichiometric composition by a pulling method, the present inventor discovered that the crucible is surrounded by a specific melt. By selecting a specific initial melt composition, crystal growth rate, and temperature gradient at the melt interface, high-quality single crystals with almost no cracks or compositional fluctuations can be obtained without replenishing the crystal growth melt. The present invention was achieved based on the discovery that
即ち、本発明の要旨は、ニオブ酸リチウム単結晶を引き
上げ法で育成する方法において、るつぼの周囲を結晶育
成融液中に混入することのない状態で結晶育成融液の近
傍組成を有する融液で包囲し、かつ結晶育成融液の初期
組成を酸化リチウム（Ｌｉ２Ｏ） ：酸化ニオブ（Ｎｂ
２Ｏ５）＝ ５４〜６０ ：４６〜４０（モル比）とし
、結晶の育成速度を０．１〜５ｇ／時間とし、融液界面
の温度勾配を２０〜６０°Ｃ／ｃｍとすることを特徴と
するニオブ酸リチウム単結晶の製造方法に存する。That is, the gist of the present invention is to provide a method for growing a lithium niobate single crystal by a pulling method, in which a melt having a composition close to that of the crystal growth melt is produced without mixing the surroundings of the crucible into the crystal growth melt. and the initial composition of the crystal growth melt is lithium oxide (Li2O):niobium oxide (Nb
2O5) = 54-60:46-40 (molar ratio), the crystal growth rate is 0.1-5 g/hour, and the temperature gradient at the melt interface is 20-60°C/cm. The present invention relates to a method for producing a lithium niobate single crystal.
以下、本発明の詳細な説明する。The present invention will be explained in detail below.
本発明において育成するニオブ酸リチウム単結晶は、化
学量論組成、即ちＬｉ０２Ｎｂ２０５＝ ５０ ： ５
０ （モル比）、近傍の組成を有するものである。The lithium niobate single crystal grown in the present invention has a stoichiometric composition, that is, Li02Nb205 = 50:5.
0 (molar ratio).
このような組成を有するニオブ酸リチウム単結晶は、第
２図から明らかなように、Ｌｉ０２Ｎｂ２０６：５８：
４２（モル比）の組成を有する融液から育成される。As is clear from FIG. 2, the lithium niobate single crystal having such a composition is Li02Nb206:58:
It is grown from a melt having a composition of 42 (molar ratio).
この融液から結晶成長を行うと、結晶の成長に伴ない融
液組成は徐々に変化し、その結果育成する結晶組成も変
化する。When crystal growth is performed from this melt, the composition of the melt gradually changes as the crystal grows, and as a result, the composition of the grown crystal also changes.
本発明においては、結晶の生産性、結晶組成の変化、歩
留り等を考慮して、結晶を育成させる内るつぼ内の融液
組成はＬｉ０２Ｎｂ２０ｓ ＝ ５４〜５８ ：４６〜
４２（モル比）とする。融液組成が帯−溶融組成に近い
ほど結晶の高歩留、高生産性が期待できるが、結晶組成
は化学量論組成からずれる。この組成領域であれば、育
成結晶の組成の変化は比較的少ない。In the present invention, in consideration of crystal productivity, changes in crystal composition, yield, etc., the composition of the melt in the inner crucible in which crystals are grown is Li02Nb20s = 54-58:46-
42 (molar ratio). The closer the melt composition is to the band-melt composition, the higher the yield and productivity of crystals can be expected, but the crystal composition deviates from the stoichiometric composition. In this composition range, there is relatively little change in the composition of the grown crystal.
本発明においては、るつぼを少なくとも２重に構成し、
内側るつぼの周囲を結晶育成融液に混入することのない
状態で融液で包囲する。これにより、ホイドの発生等欠
陥の発生が大幅に減少するので好ましい。通常、２重る
つぼを用い、内るつぼと外るつぼの間を融液で満たず。In the present invention, the crucible is configured in at least two layers,
The inner crucible is surrounded by the melt without being mixed with the crystal growth melt. This is preferable because it greatly reduces the occurrence of defects such as the formation of hoids. Usually, a double crucible is used, and the space between the inner and outer crucibles is not filled with melt.
各るつぼ間を満たす融液は、内るつぼ内の結晶育成融液
の汚染等を防止するため、結晶育成融液と同一組成ある
いはその近傍の組成を有するものが用いられる。通常、
融点が１１６０〜１２５０°Ｃの範囲であり、結晶育成
融液の融点より３０°Ｃ以上高くない組成であるもの、
例えばＬｉ２ＯＮｂ２Ｏ５＝ ３６〜６０ ：６４〜４
０（モル比）の組成のものが用いられる。The melt filling between each crucible has the same composition as the crystal growth melt or a composition close to that of the crystal growth melt in order to prevent contamination of the crystal growth melt in the inner crucible. usually,
The composition has a melting point in the range of 1160 to 1250°C and is not higher than the melting point of the crystal growth melt by 30°C or more,
For example, Li2ONb2O5 = 36-60:64-4
A composition having a composition of 0 (molar ratio) is used.
このようにるつぼの周囲を融液で包囲すると、結晶育成
融液表面の温度分布及び温度の時間的変化が緩やかにな
るため、結晶成長のミクロ的な変動が減少し、欠陥発生
が大幅に減少すると思われる。この効果は、抵抗加熱炉
より高周波加熱炉を用いた場合に顕著に現われる。Surrounding the crucible with melt in this way slows down the temperature distribution on the surface of the crystal growth melt and the temporal changes in temperature, reducing microscopic fluctuations in crystal growth and greatly reducing the occurrence of defects. It seems that it will. This effect is more pronounced when a high-frequency heating furnace is used than a resistance heating furnace.
本発明においては、融液界面の温度勾配を２０〜６０°
Ｃ／ｃｍとする。融液界面の温度勾配は、組成的過冷却
を抑えるという観点から考えると大きいほうが望ましい
が、６０°Ｃ／ａｍを越えると結晶育成中の結晶自身に
加わる歪みのために結晶にクラックが発生し、２０°Ｃ
／ｃｍより小さいと結晶形状を制御できなくなる。In the present invention, the temperature gradient at the melt interface is set to 20 to 60°.
C/cm. A large temperature gradient at the melt interface is desirable from the perspective of suppressing compositional supercooling, but if it exceeds 60°C/am, cracks will occur in the crystal due to strain applied to the crystal itself during crystal growth. , 20°C
If it is smaller than /cm, the crystal shape cannot be controlled.
本発明においては、結晶育成速度を０．１〜５ｇ／時間
とする。結晶育成速度は、組織的過冷却を抑えるという
観点から考えると遅い方が望ましいが、０．１ｇ／時間
よりも遅いと結晶育成に長時間装してしまうため有効に
育成させることができず、５ｇ／時間より速いとセル成
長が起きてクラックが発生したり、多結晶が育成してし
まう。In the present invention, the crystal growth rate is 0.1 to 5 g/hour. A slower crystal growth rate is desirable from the perspective of suppressing structural supercooling, but if it is slower than 0.1 g/hour, crystal growth will take a long time and cannot be grown effectively. If it is faster than 5 g/hour, cell growth will occur and cracks will occur, or polycrystals will grow.
また、本発明においては、結晶育成が進むと融液が減少
し、融液の温度勾配が大きくなりすぎ、結晶にクラック
が発生することがあるが、これは、加熱炉等を調節して
温度勾配を小さくすることにより解決できる。温度勾配
を調整しない場合でも、本発明によれば３０％近い歩留
りで単結晶を育成することが可能である。In addition, in the present invention, as crystal growth progresses, the melt decreases and the temperature gradient of the melt becomes too large, which may cause cracks in the crystal. This can be solved by reducing the slope. Even when the temperature gradient is not adjusted, according to the present invention, it is possible to grow single crystals with a yield of nearly 30%.
本発明において、引き上げ法としては特に限定されず、
例えば、ＣＺ法、キロプラス法等が挙げられる。In the present invention, the pulling method is not particularly limited,
Examples include the CZ method and the kiloplus method.
［実施例Ｊ
以下、本発明を実施例により更に詳細に説明するが、本
発明はその要旨を越えない限り実施例に限定されるもの
ではない。[Example J Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples unless the gist thereof is exceeded.
実施例１
第１図に示すように、１１０ＫＨｚの高周波誘導加熱炉
内に直径８０ｍｍ、高さ８０ｍｍ、厚さ１ｍｍの白金（
Ｐｔ）製るつぼを設置し、更にその内側に直径７０ｍｍ
、高さ５０ｍｍ、厚さ１ｍｍのｐｔ製るつぼを設置した
。Example 1 As shown in Fig. 1, a platinum (diameter 80 mm, height 80 mm, thickness 1 mm) was placed in a 110 KHz high frequency induction heating furnace.
A crucible made of Pt) was installed, and a diameter of 70 mm was placed inside it.
A PT crucible with a height of 50 mm and a thickness of 1 mm was installed.
外るつぼには、酸化リチウム（Ｌｉ２Ｏ）３６モル％、
酸化−１−ｔ フ（ＶＸ Ｎｂ２Ｏ５）６４モル％（７
）原料を６５０ｇ、内るつぼにはＬｉ２Ｏ５７モル％、
Ｎｂ２Ｏ５４３モル％の原料を５４０ｇ入れ、１２２０
°Ｃまで加熱してＬｉ２Ｏ及びＮｂ２Ｏ５を融解した。In the outer crucible, 36 mol% of lithium oxide (Li2O),
Oxidation-1-t fu(VX Nb2O5) 64 mol% (7
) 650g of raw materials, 57 mol% of Li2O in the inner crucible,
Add 540g of raw material containing 43 mol% of Nb2O, and
Heating to °C melted Li2O and Nb2O5.
内るつぼ内の融液を融点近くまで降温し、ＬｉＮｂＯ３
の種結晶（１１１）方位を浸した。このとき、融液界面
の温度勾配は４０°Ｃ／ｃｍであった。ネッキング及び
肩出し後、結晶回転数２０ｒｐｍ、結晶育成速度１．２
ｇ／時間、直径３２ｍｍで結晶育成を行った。The temperature of the melt in the inner crucible is lowered to near the melting point, and LiNbO3
The seed crystal (111) orientation was immersed. At this time, the temperature gradient at the melt interface was 40°C/cm. After necking and shoulder lifting, crystal rotation speed 20 rpm, crystal growth rate 1.2
Crystal growth was performed at a rate of 32 mm in diameter.
結晶を１３０ｇ育成した後、結晶を融液表面から１０ｍ
ｍ離し、約２４時間かけて冷却して結晶を取り出した。After growing 130g of crystals, grow the crystals 10m from the melt surface.
The crystals were taken out after cooling for about 24 hours.
得られた結晶は、ボイドやクラックのない単結晶であり
、示差熱天秤分析法により、キュリー温度測定を行った
ところ、Ｔｃ ＝ １１９３−１２００°Ｃであり、組
成に換算すると、Ｌｉ２ＯＮｂ２０５＝ ４９．８〜５
０：５０．２〜５０（モル比）であり、はぼ一定の組成
で育成されていた。The obtained crystal was a single crystal with no voids or cracks, and when the Curie temperature was measured by differential thermal balance analysis, it was found to be Tc = 1193-1200°C, and when converted to a composition, Li2ONb205 = 49. 8-5
The ratio was 0:50.2 to 50 (molar ratio), and it was grown with a nearly constant composition.
比較例１
直径６０ｍｍ、高さ５０ｍｍ、厚さ１ｍｍのｐｔ製るつ
ぼを１個使用し、Ｌｉ２Ｏ５７モル％、Ｎｂ２Ｏ，４３
モル％の原料を３１０ｇ融解したこと以外は、実施例１
と同様にして結晶育成を行った。Comparative Example 1 Using one PT crucible with a diameter of 60 mm, a height of 50 mm, and a thickness of 1 mm, Li2O57 mol%, Nb2O,43
Example 1 except that 310 g of the raw material of mol % was melted.
Crystals were grown in the same manner.
結晶を７３ｇ育成した後、結晶を融液表面から１０ｍｍ
離し、約２４時間かけて冷却して結晶を取り出した。After growing 73g of crystals, place the crystals 10mm from the melt surface.
It was separated, cooled for about 24 hours, and the crystals were taken out.
得られた結晶には、全面にボイドが発生しており、また
、ボイドを起点としたクラックも発生していた。In the obtained crystal, voids were generated all over the surface, and cracks were also generated starting from the voids.
比較例２
結晶育成速度を１０ｇ／時間としたこと以外は実施例１
と同様にして結晶を育成した。Comparative Example 2 Example 1 except that the crystal growth rate was 10 g/hour
Crystals were grown in the same manner.
得られた結晶は、セル成長が原因と思われるクラックが
全面に発生していた。The obtained crystal had cracks all over it, which were thought to be caused by cell growth.
参考例１
結晶育成量を２６０ｇとしたこと以外は実施例１と同様
にして結晶を育成した。Reference Example 1 Crystals were grown in the same manner as in Example 1 except that the amount of crystal growth was 260 g.
得られた結晶は、初期の約１６０ｇは透明なボイドのな
い結晶であったが、それ以降育成された結晶は白色をし
たセラミック状であった。これは、結晶育成量が多くな
って融液の温度勾配が大きくなりすぎたことに起因して
いる。About 160 g of the obtained crystals were initially transparent without voids, but the crystals grown thereafter were white and ceramic-like. This is because the amount of crystal growth has increased and the temperature gradient of the melt has become too large.
透明部の結晶を実施例１と同様にして組成分析したとこ
ろ、ＬｉｚＯＮｂ２Ｏ５＝ ４９．８〜５０ ： ５０
．２〜５０（モル比）であり、はぼ一定の組成で育成さ
れていた。When the crystal in the transparent part was analyzed for composition in the same manner as in Example 1, LizONb2O5 = 49.8-50:50
．． 2 to 50 (molar ratio), and was grown with a nearly constant composition.
単結晶育成の歩留りは約３０％であった。The yield of single crystal growth was about 30%.
［発明の効果］
本発明によると、結晶育成融液の補給をすることなく、
クラックがなく均質な化学量論組成近傍４゜
のニオブ酸リチウムの単結晶を得ることができるため工
業的に有用である。[Effect of the invention] According to the present invention, without replenishing the crystal growth melt,
This method is industrially useful because it is possible to obtain a single crystal of lithium niobate with a homogeneous stoichiometric composition of 4° without cracks.
第１図は、本発明の実施例で使用した高周波誘導加熱炉
の概略断面図である。第１図中、１は育成した単結晶、
２は内るつぼ、３は外るつぼ、４は単結晶育成融液、５
はるつぼ間の融液、６は種結晶、７はヒーター、８はア
フターヒーター、９は耐火物を示す。
第２図は、Ｌｉ２Ｏ−Ｎｂ２Ｏ５系のニオブ酸リチウム
の状態図（Ｊ、 Ａｐｐｌ、 Ｐｈｙｓ、 ４２．５（
１９７１） Ｊ、 Ｒ，Ｃａｒｒｕｔｈｅｒｓｅｔａｌ
、）である。
第３図は、Ｌｉ２ＣＯ３−Ｎｂ２Ｏ５系のニオブ酸リチ
ウムの状態図（Ｊ、 Ｃｒｙｓ、 Ｇｒｏｗ、 ３．４
．、（１９６８） Ｐ、 Ｌｅｎｎｅｒ ｅｔａｌ、）
である。FIG. 1 is a schematic sectional view of a high frequency induction heating furnace used in an example of the present invention. In Figure 1, 1 is the grown single crystal;
2 is an inner crucible, 3 is an outer crucible, 4 is a single crystal growth melt, 5
The melt between the crucibles, 6 a seed crystal, 7 a heater, 8 an after-heater, and 9 a refractory. Figure 2 shows the phase diagram of Li2O-Nb2O5 system lithium niobate (J, Appl, Phys, 42.5 (
1971) J, R, Carruthersetal
, ). Figure 3 shows the phase diagram of Li2CO3-Nb2O5-based lithium niobate (J, Crys, Grow, 3.4
．． , (1968) P., Lenner et al.
It is.
Claims (1)
方法において、るつぼの周囲を結晶育成融液中に混入す
ることのない状態で結晶育成融液の近傍組成を有する融
液で包囲し、かつ結晶育成融液の初期組織を酸化リチウ
ム（Ｌｉ＿２Ｏ）：酸化ニオブ（Ｎｂ＿２Ｏ＿５）＝５
４〜６０：４６〜４０（モル比）とし、結晶の育成速度
を０．１〜５ｇ／時間とし、融液界面の温度勾配を２０
〜６０℃／ｃｍとすることを特徴とするニオブ酸リチウ
ム単結晶の製造方法。(1) In a method of growing a lithium niobate single crystal by a pulling method, the crucible is surrounded by a melt having a composition close to that of the crystal growth melt without being mixed into the crystal growth melt, and The initial structure of the crystal growth melt is lithium oxide (Li_2O):niobium oxide (Nb_2O_5) = 5
4-60:46-40 (molar ratio), crystal growth rate 0.1-5 g/hour, temperature gradient at the melt interface 20
A method for producing a lithium niobate single crystal, characterized in that the temperature is 60° C./cm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20089490A JPH0489398A (en) | 1990-07-27 | 1990-07-27 | Production of lithium niobate single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20089490A JPH0489398A (en) | 1990-07-27 | 1990-07-27 | Production of lithium niobate single crystal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0489398A true JPH0489398A (en) | 1992-03-23 |
Family
ID=16432026
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20089490A Pending JPH0489398A (en) | 1990-07-27 | 1990-07-27 | Production of lithium niobate single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0489398A (en) |
-
1990
- 1990-07-27 JP JP20089490A patent/JPH0489398A/en active Pending
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