JPS63151696A - Method for growing crystal - Google Patents
Method for growing crystalInfo
- Publication number
- JPS63151696A JPS63151696A JP29713686A JP29713686A JPS63151696A JP S63151696 A JPS63151696 A JP S63151696A JP 29713686 A JP29713686 A JP 29713686A JP 29713686 A JP29713686 A JP 29713686A JP S63151696 A JPS63151696 A JP S63151696A
- Authority
- JP
- Japan
- Prior art keywords
- crystal
- growth
- impurity
- seed
- impurity concentration
- 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 63
- 238000000034 method Methods 0.000 title abstract description 14
- 239000012535 impurity Substances 0.000 claims abstract description 38
- 239000000126 substance Substances 0.000 claims abstract description 6
- 238000002109 crystal growth method Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 11
- 238000009826 distribution Methods 0.000 abstract description 10
- 239000007788 liquid Substances 0.000 abstract description 7
- 239000007791 liquid phase Substances 0.000 description 15
- 239000000203 mixture Substances 0.000 description 13
- 238000010586 diagram Methods 0.000 description 7
- 238000005204 segregation Methods 0.000 description 6
- 230000005486 microgravity Effects 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 4
- 239000003708 ampul Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000010453 quartz Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000007747 plating Methods 0.000 description 2
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000009828 non-uniform distribution Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
Abstract
Description
【発明の詳細な説明】
〔概要〕
結晶融液、または溶液の対流が発生しない微小重力環境
における結晶の成長方法において、成長結晶の利用率を
高くするために、その組成の不均一となる部分を最小と
することが重要である。そのために、種結晶の表面に不
純物となる物質、または不純物を含む物質を真空蒸着や
メッキ等により付着させ、成長に先立ってその一部をメ
ルトバックした後、結晶成長を開始することにより成長
結晶の組成の均一化をはかる方法を提起する。[Detailed Description of the Invention] [Summary] In a method for growing a crystal in a microgravity environment where convection of a crystal melt or solution does not occur, in order to increase the utilization rate of the growing crystal, a portion whose composition is non-uniform is provided. It is important to minimize the For this purpose, a substance that becomes an impurity or a substance containing an impurity is attached to the surface of the seed crystal by vacuum evaporation or plating, and a part of it is melted back before crystal growth, and then crystal growth is started. We propose a method for making the composition uniform.
本発明は液相成長法において、成長結晶の組成を均一化
する方法に関する。The present invention relates to a method for uniformizing the composition of a grown crystal in a liquid phase growth method.
液相成長法は化合物半導体の結晶成長に用いられる。The liquid phase growth method is used for crystal growth of compound semiconductors.
液相成長法において、結晶の融液、または溶液の組成と
、成長した結晶の組成は偏析により異なった値となる。In the liquid phase growth method, the composition of the crystal melt or solution and the composition of the grown crystal have different values due to segregation.
そのため、成長が進むにつれて液相中の組成が変化し、
これにともなって成長する結晶の組成も ′変わって
ゆく。すなわち、成長の始めと終りでは成長結晶の組成
が異なる。Therefore, as growth progresses, the composition in the liquid phase changes,
Along with this, the composition of the growing crystal also changes. That is, the composition of the grown crystal differs at the beginning and end of growth.
化合物半導体はその組成の変化により、格子定数や、エ
ネルギギャップ等が変化するため、組成の均一化はデバ
イス作成上桟めて重要である。Since the lattice constant, energy gap, etc. of a compound semiconductor change due to changes in its composition, uniformity of the composition is extremely important for device fabrication.
液相成長法では、前記のように偏析により液相中の組成
が変化し、成長する結晶の組成も変化する。In the liquid phase growth method, as described above, the composition in the liquid phase changes due to segregation, and the composition of the growing crystal also changes.
しかし、液相中に対流や浮力による攪拌がない微小重力
環境のような状態では、はぼ一定の組成をもった結晶を
成長させることができる。However, in conditions such as a microgravity environment where there is no agitation due to convection or buoyancy in the liquid phase, it is possible to grow crystals with a more or less constant composition.
すなわち、成長速度を融液中の不純物の拡散速度より大
きくすると、例えば偏析係数が１より小さい場合は、初
期に成長する結晶中の不純物濃度−は液相中の濃度に偏
析係数をかけたもので、液相中の濃度より小さくなり、
固液界面近くの液相中の不純物濃度は他の部分より高く
なる。In other words, if the growth rate is greater than the diffusion rate of impurities in the melt, for example if the segregation coefficient is less than 1, the impurity concentration in the initially growing crystal - is the concentration in the liquid phase multiplied by the segregation coefficient. , it becomes smaller than the concentration in the liquid phase,
The impurity concentration in the liquid phase near the solid-liquid interface is higher than in other parts.
このとき、対流による液相の攪拌が起これば、液相中の
不純物濃度は平均化される。そのために成長した結晶の
不純物濃度は徐々に高くなってゆく。At this time, if the liquid phase is stirred by convection, the impurity concentration in the liquid phase is averaged. Therefore, the impurity concentration of the grown crystal gradually increases.
これに対して、微小重力下では対流を生じないため、液
相中の不純物分布の不均一を解消させる力は拡散だけで
ある。On the other hand, since no convection occurs under microgravity, diffusion is the only force that eliminates the non-uniform distribution of impurities in the liquid phase.
そのため、成長速度を不純物の拡散速度より速くすれば
、固液界面の不純物濃度は実効的な偏析係数が１になる
まで高くなり、成長した結晶の成長方向での不純物分布
は均一となる。Therefore, if the growth rate is made faster than the impurity diffusion rate, the impurity concentration at the solid-liquid interface increases until the effective segregation coefficient becomes 1, and the impurity distribution in the growth direction of the grown crystal becomes uniform.
微小重力環境を長時間得るためにはスペースシャトル等
の軌道飛行船を使う必要がある。そのために使用できる
電力や時間が限られるので不純物濃度の一定な部分をよ
り多く取ることが必要となってくる。In order to obtain a microgravity environment for a long time, it is necessary to use an orbital airship such as the space shuttle. Since the power and time that can be used for this are limited, it is necessary to take a larger portion of the impurity concentration at a constant level.
しかし、従来の微小重力環境下の成長では、成、長初期
において、固液界面の不純物濃度が一定になるまでは成
長結晶中の不純物濃度は変化していることになり、成長
結晶の利用率が低下する。However, in conventional growth under a microgravity environment, the impurity concentration in the growing crystal changes during the early stages of growth and growth until the impurity concentration at the solid-liquid interface becomes constant, and the utilization rate of the growing crystal increases. decreases.
上記問題点の解決は、成長初期にあたる材料部分の不純
物濃度を他の部分と変えることにより、成長方向の不純
物濃度分布を一定にすることにより達成される。The above problem can be solved by making the impurity concentration distribution in the growth direction constant by changing the impurity concentration in the material portion at the initial stage of growth from that in other portions.
すなわち、成長結晶に導入する不純物を含む物質を種結
晶の表面に付着させ、核種結晶を結晶融液と接触させて
その一部をメルトバックした後、結晶成長を開始する本
発明による結晶成長方法により達成される。That is, the crystal growth method according to the present invention involves attaching a substance containing impurities to be introduced into a growing crystal to the surface of a seed crystal, bringing the nuclide crystal into contact with a crystal melt to melt back a portion of the crystal, and then starting crystal growth. This is achieved by
本発明は成長初期にあたる材料部分の不純物濃度を他の
部分と変えることにより、固液界面近くの液相中の不純
物濃度を速く平衡濃度に達するようにして、成長結晶の
成長方向不純物濃度分布が一定の部分を多く取れるよう
にしたものである。In the present invention, the impurity concentration in the liquid phase near the solid-liquid interface quickly reaches the equilibrium concentration by changing the impurity concentration in the material part at the initial stage of growth from that in other parts, thereby improving the impurity concentration distribution in the growth direction of the growing crystal. It is designed so that a large amount of a certain portion can be taken.
本発明をブリッジマン成長法に実施した例を第１図を用
いて説明する。An example in which the present invention is applied to the Bridgman growth method will be explained with reference to FIG.
ブリッジマン成長法は化合物半導体結晶を得るために多
く用いられている。この方法は空間的に温度勾配をもっ
た炉中を、結晶溶液が徐々に通過して結晶成長を行うも
ので、変形ゾーンメルチイブとも呼ばれ、本来はメルト
の先端に自然発生した結晶槓より成長が行われるが、最
近は確実な単結晶を得るために種結晶が用いられるよう
になった。The Bridgman growth method is often used to obtain compound semiconductor crystals. In this method, a crystal solution gradually passes through a furnace with a spatial temperature gradient to grow crystals, and is also called a deformation zone melt. Seed crystals have recently been used to obtain reliable single crystals.
第１図（ｌｊ、（２）は本発明を説明する図で、それぞ
れ成長方向の距離に対する種結晶と成長材料の配置と、
不純物濃度の関係を示す図である。FIG. 1 (lj, (2)) is a diagram explaining the present invention, and shows the arrangement of the seed crystal and the growth material with respect to the distance in the growth direction, and
FIG. 3 is a diagram showing the relationship between impurity concentrations.
第１図（１＞において、成長材料１として、例えばガリ
ウム砒素（ＧａＡｓ、）を用い、不純物（例えばＴｅ）
の濃度を一定（１，２Ｘ１０”ｃｍ−”）にする。In FIG. 1 (1>), for example, gallium arsenide (GaAs) is used as the growth material 1, and impurities (for example, Te) are used.
The concentration of is kept constant (1.2 x 10"cm-").
種結晶２の表面に不純物となる物質（Ｔｅ）を薄着、ま
たはメッキにより付着し、厚さ０．１ μｍの不純物
層３を形成する。An impurity substance (Te) is deposited on the surface of the seed crystal 2 by thin deposition or plating to form an impurity layer 3 having a thickness of 0.1 μm.
成長装置（例えば石英アンプル）内に、種結晶２、不純
物層３、成長材料１の順に並べて配置する。石英アンプ
ルを所定の温度勾配５°Ｃ／ｃｍをもった炉中に入れ、
成長材料１を所定の熔融温度１２３８℃に保って溶液と
し、炉中を成長材料１より種結晶２の方向に石英アンプ
ルを徐々に移動させることにより、所定の速度で温度降
下させて種結晶から、結晶を成長してゆく。A seed crystal 2, an impurity layer 3, and a growth material 1 are arranged in this order in a growth apparatus (for example, a quartz ampoule). Place the quartz ampoule in a furnace with a predetermined temperature gradient of 5°C/cm,
The growth material 1 is kept at a predetermined melting temperature of 1238°C to form a solution, and by gradually moving the quartz ampoule in the furnace from the growth material 1 toward the seed crystal 2, the temperature is lowered at a predetermined rate and the seed crystal is removed. , growing crystals.
第１図（２）は、成長方向の距離に対する種結晶と、不
純物層と、成長材料との不純物濃度分布を模式第２図は
成長結晶の成長方向の不純物分布を示す図である。FIG. 1(2) is a diagram showing the impurity concentration distribution of the seed crystal, the impurity layer, and the growth material with respect to the distance in the growth direction, and FIG. 2 is a diagram showing the impurity distribution in the growth direction of the grown crystal.
この図は、成長速度１ ｃｍ／ｈ 、偏析係数０．３、
拡散係数５ Ｘ １０−５ｃｍ２／ｓｅｃとして、成長
結晶の成長方向の不純物分布を計算により求めたもので
ある。This figure shows a growth rate of 1 cm/h, a segregation coefficient of 0.3,
The impurity distribution in the growth direction of the grown crystal was calculated using a diffusion coefficient of 5×10 −5 cm 2 /sec.
図において、（ａ）は種結晶に不純物を付着しない従来
例による場合で、成長した結晶は成長初期において約１
ｍｍにわたって濃度が変化している。In the figure, (a) is a conventional example in which impurities are not attached to the seed crystal, and the grown crystal has approximately 1
The concentration varies over mm.
これに対して、（ｂ）は本発明による場合で、種結晶を
約１ｃｍメルトバックした後に成長したもので、この場
合の濃度の変化している部分は従来例の約半分の０．５
ｃｍとなった。On the other hand, (b) is the case according to the present invention, which grew after the seed crystal was melted back by about 1 cm, and the part where the concentration changed in this case was 0.5 cm, which is about half of the conventional example.
cm.
実施例においては、ブリ・ノジマン成長法について説明
したが、他の液相成長法についても本発明は同様の効果
を有する。In the examples, the Bry-Nodjman growth method has been described, but the present invention has similar effects with other liquid phase growth methods.
以上詳細に説明したように本発明によれば、成長初期に
おける不純物濃度分布が変動する部分を少なくできるの
で、均一な濃度分布をもった部分をより多（得ることが
できる。As described in detail above, according to the present invention, it is possible to reduce the portion where the impurity concentration distribution fluctuates in the early stage of growth, thereby making it possible to obtain more portions having a uniform concentration distribution.
第１図（１）、（２）は本発明を説明する図で、それぞ
れ成長方向の距離に対する種結晶と成長材料の配置と、
不純物濃度の関係を示す図、
第２図は成長結晶の成長方向の不純物分布を示す図であ
る。
図において、
１は成長材料、
２は種結晶、
３は種結晶に付着した不純物層FIGS. 1 (1) and (2) are diagrams explaining the present invention, and show the arrangement of the seed crystal and the growth material with respect to the distance in the growth direction, respectively, and
FIG. 2 is a diagram showing the relationship between impurity concentrations. FIG. 2 is a diagram showing the impurity distribution in the growth direction of a grown crystal. In the figure, 1 is the growth material, 2 is the seed crystal, and 3 is the impurity layer attached to the seed crystal.
Claims (1)
に付着させ、該種結晶を結晶融液、または溶液と接触さ
せてその一部をメルトバックした後、該種結晶と該結晶
融液、または溶液界面より徐々に結晶成長を開始するこ
とを特徴とする結晶成長方法。A substance containing impurities to be introduced into the growing crystal is attached to the surface of the seed crystal, and the seed crystal is brought into contact with a crystal melt or solution to melt back a part of it, and then the seed crystal and the crystal melt, Or a crystal growth method characterized by starting crystal growth gradually from the solution interface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29713686A JPS63151696A (en) | 1986-12-12 | 1986-12-12 | Method for growing crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29713686A JPS63151696A (en) | 1986-12-12 | 1986-12-12 | Method for growing crystal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63151696A true JPS63151696A (en) | 1988-06-24 |
Family
ID=17842674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29713686A Pending JPS63151696A (en) | 1986-12-12 | 1986-12-12 | Method for growing crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63151696A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5406905A (en) * | 1993-05-28 | 1995-04-18 | Simco/Ramic Corporation | Cast dopant for crystal growing |
-
1986
- 1986-12-12 JP JP29713686A patent/JPS63151696A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5406905A (en) * | 1993-05-28 | 1995-04-18 | Simco/Ramic Corporation | Cast dopant for crystal growing |
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