JPH0458438B2 - - Google Patents
Info
- Publication number
- JPH0458438B2 JPH0458438B2 JP14033787A JP14033787A JPH0458438B2 JP H0458438 B2 JPH0458438 B2 JP H0458438B2 JP 14033787 A JP14033787 A JP 14033787A JP 14033787 A JP14033787 A JP 14033787A JP H0458438 B2 JPH0458438 B2 JP H0458438B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- crystal
- ppm
- raw material
- cracks
- 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.)
- Expired
Links
- 239000013078 crystal Substances 0.000 claims description 27
- 239000002994 raw material Substances 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 6
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims description 3
- 239000000155 melt Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 2
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims 1
- 239000002253 acid Substances 0.000 claims 1
- 229910052744 lithium Inorganic materials 0.000 claims 1
- 229910052715 tantalum Inorganic materials 0.000 claims 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims 1
- 239000012535 impurity Substances 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000002109 crystal growth method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Description
〔産業上の利用分野〕
本発明は、タンタル酸リチウム単結晶（以下単
結晶という）を製造する方法に係り、特に育成し
た単結晶の不純物をコントロールすることにより
単結晶のクラツクを防止する単結晶の製造方法に
関する。
〔従来の技術〕
単結晶の製造はるつぼ内の多結晶原料を所定の
温度（例えば1670℃）まで昇温して溶融し、融液
を所定温度（例えば1650℃）まで降温してシード
付けを行なつた後、シードを回転させつつ引き上
げてネツク部、コーン部、ボデイ部を有する単結
晶を育成する。次回の単結晶の育成では前回残つ
た原料に前回育成した結晶の重量分を追加し再度
単結晶を育成を行なつている。
〔発明が解決しようとする問題点〕
上記方法で追加チヤージをしながら育成する方
法では、追加チヤージを繰り返すと回を重ねる毎
に単結晶のクラツクの発生率が高くなるという問
題点があり、その為原料の追加チヤージ数を少な
くする必要があつた。
本発明は上記の点に鑑み、育成後の単結晶のク
ラツクの発生を大幅に減少させ、クラツクを生じ
せしめる事なく原料の追加チヤージ回数を増やす
ための単結晶育成法を提供することを目的とする
ものである。
〔問題点を解決するための手段〕
本発明の単結晶の製造方法は、上記目的達成の
ため、るつぼ内に装入した原料を加熱溶融後種子
結晶を降下し融液に接触させ回転させながら引き
上げ単結晶を育成させる方法において、上記原料
のLi／Taモル比が0.91から0.97よりなる原料で、
Zrが200ppm以下、Alが80ppm以下、Caが20ppm
以下であることを特徴とする単結晶の製造方法で
ある。
〔作用〕
本発明において、発明者らはまず原料の追加チ
ヤージ数の不純物の関係及び単結晶クラツクとの
関係を詳細に調査した結果、表１のようにZrが
200ppm以上、Alが80ppm以上、Caが20ppm以上
になると、結晶のＺ軸方向にクラツクが入ること
が分かつた。クラツクの原因としては、結晶の育
成時の結晶の成長速度の速いＺ軸方向に、Zr、
Al、Caが取り込まれ転位や亜粒界などの結晶欠
陥が発生するためと考えられる。また原料の追加
チヤージ数が多くなる程、Zr、Al、Caが多くな
る傾向があつたが、ZrとAlは耐火物として使用
しているZrO2やAl2O3に混入するための考えら
れ、Caは追加チヤージにより不純物が濃縮され
るためと推定される。
[Industrial Application Field] The present invention relates to a method for producing a lithium tantalate single crystal (hereinafter referred to as a single crystal), and in particular, a method for producing a single crystal that prevents cracking of the single crystal by controlling impurities in the grown single crystal. Relating to a manufacturing method. [Prior art] To produce a single crystal, a polycrystalline raw material in a crucible is heated to a predetermined temperature (for example, 1670°C) and melted, and the melt is cooled to a predetermined temperature (for example, 1650°C) to seed. After this, the seed is pulled up while rotating to grow a single crystal having a neck portion, a cone portion, and a body portion. In the next single crystal growth, the weight of the previously grown crystal is added to the raw material left over from the previous time, and the single crystal is grown again. [Problems to be Solved by the Invention] In the above method of growing while performing additional charging, there is a problem that the occurrence of cracks in the single crystal increases each time the additional charging is repeated. Therefore, it was necessary to reduce the number of additional charges of raw materials. In view of the above points, an object of the present invention is to provide a single crystal growth method that can significantly reduce the occurrence of cracks in single crystals after growth and increase the number of additional charges of raw materials without causing cracks. It is something to do. [Means for Solving the Problems] In order to achieve the above object, the method for producing a single crystal of the present invention involves heating and melting the raw material charged in a crucible, and then lowering the seed crystal to contact with the melt while rotating. In the method of growing a pulled single crystal, the above raw material has a Li/Ta molar ratio of 0.91 to 0.97,
Zr is 200ppm or less, Al is 80ppm or less, Ca is 20ppm
This is a method for producing a single crystal characterized by the following. [Function] In the present invention, the inventors first investigated in detail the relationship between impurities and the number of additional charges in the raw material and the relationship with single crystal cracks, and as a result, as shown in Table 1, Zr
It was found that cracks appear in the Z-axis direction of the crystal when the concentration exceeds 200 ppm, Al exceeds 80 ppm, and Ca exceeds 20 ppm. The cause of the crack is that Zr,
This is thought to be because crystal defects such as dislocations and subgrain boundaries occur due to the incorporation of Al and Ca. There was also a tendency for Zr, Al, and Ca to increase as the number of additional charges of raw materials increased, but it is thought that Zr and Al are mixed into ZrO 2 and Al 2 O 3 used as refractories. , Ca is presumed to be due to impurities being concentrated by additional charging.
上記のように本発明によれば、育成後の単結晶
のクラツクの発生を大幅に減少させ、さらに単結
晶にクラツクの発生する直前まで原料の追加チヤ
ージをすることができ、単結晶育成歩留の大幅な
向上および原価低減が達成できる。
As described above, according to the present invention, it is possible to significantly reduce the occurrence of cracks in single crystals after growth, and additionally charge the raw material until just before cracks occur in the single crystal, thereby increasing the single crystal growth yield. A significant improvement in performance and cost reduction can be achieved.
第１図は本発明に係り実験的に得られた原料追
加チヤージ回数と、Zr、Al、Caの不純物濃度の
相関図である。
FIG. 1 is a correlation diagram between the number of additional charges of raw materials and the impurity concentrations of Zr, Al, and Ca, which were experimentally obtained according to the present invention.
Claims (1)
晶を降下し融液に接触させ回転させながら引き上
げタンタル酸リチウム単結晶を育成させる方法に
おいて、Li／Taモル比が0.91から0.97よりなるタ
ンタル酸リチウム単結晶用原料で、Zrを200ppm
以下、Alを80ppm以下、Caを20ppm以下にする
ことを特徴とするタンタル酸リチウム単結晶の製
造方法。1 In a method of filling a crucible with raw materials, heating and melting the seed crystal, lowering the seed crystal, bringing it into contact with the melt, and pulling it up while rotating to grow a lithium tantalate single crystal, tantalum acid having a Li/Ta molar ratio of 0.91 to 0.97 is used. Raw material for lithium single crystal with 200ppm Zr
The following describes a method for producing a lithium tantalate single crystal, which is characterized by reducing Al to 80 ppm or less and Ca to 20 ppm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14033787A JPS63303895A (en) | 1987-06-04 | 1987-06-04 | Production of lithium tantalate single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14033787A JPS63303895A (en) | 1987-06-04 | 1987-06-04 | Production of lithium tantalate single crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63303895A JPS63303895A (en) | 1988-12-12 |
| JPH0458438B2 true JPH0458438B2 (en) | 1992-09-17 |
Family
ID=15266481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14033787A Granted JPS63303895A (en) | 1987-06-04 | 1987-06-04 | Production of lithium tantalate single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63303895A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4046884A1 (en) | 2021-02-17 | 2022-08-24 | Toyota Jidosha Kabushiki Kaisha | Collision avoidance assist apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4924817B2 (en) * | 2007-02-22 | 2012-04-25 | 住友金属鉱山株式会社 | Lithium tantalate substrate and manufacturing method thereof |
-
1987
- 1987-06-04 JP JP14033787A patent/JPS63303895A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4046884A1 (en) | 2021-02-17 | 2022-08-24 | Toyota Jidosha Kabushiki Kaisha | Collision avoidance assist apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63303895A (en) | 1988-12-12 |
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