JPH0279422A - Liquid phase epitaxial growth device and growth method - Google Patents

Abstract

PURPOSE:To thicken a GaAlAs growth layer by holding the growth face of the substrate of a compound semiconductor toward the bottom as a wafer holder, and providing a reservoir in a melt holder which can shift relatively to its wafer holder such that the fused liquid contacts with the lower exposed face of the substrate of a compound semiconductor. CONSTITUTION:Fused liquid 4 is prepared by adding GaAs by 6g, Al by 600mg, Zn by 600mg into Ga 100g. And it is maintained for about one hour at a temperature of 860-950 deg.C in the condition that the substrate 2 and the fused liquid 4 are separated. Thereafter, a wafer holder 1 is slid so as to bring the lower exposed face of the substrate 2 into contact with the upper face of the fused liquid 4, and then it is cooled at a temperature gradient of 0.5-3 deg.C/min. so as to epitaxially grow it, and at a temperature of 600-700 deg.C the growth is stopped. For the thickness of a GaAlAs epitaxial growth layer which is formed this way, the growth layer becomes thicker, the more the thickness of the fused liquid 4 increases.

Description

【発明の詳細な説明】 （イ）産業上の利用分野 本発明はＧａＡｌＡｓ液相エピタキ液相エピタキシャル
成長上ピタキシャル成長装置及び成長方法に関する。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a GaAlAs liquid phase epitaxial growth apparatus and a growth method.

（ロ）ＵＣ来の技術 従来より化合物半導体、とりわけＧａＡρＡｓの液相エ
ピタキシャル成長は特開昭６３−５１６２４号公報の如
くスライド法により行っており、第３図に示す様に下側
ホルダ（３１）に基板（−ノエハ”）　（３２）を配置
し、その上に融液（３４１（３４）を摺動移動させて基
板（３２）の上面と融液（３４）の下面とを接触させ、
徐冷してエピタキシャル成長させている。そして特にＧ
　ａ　ＡρＡｓ発光素子においては基板（３２）として
ＧａＡｓを用いていたが、Ｇ　＝ｉ　ＡＲＡｓ成長層は
特開昭６０−２０６１８４号公報に示されるように１５
〜４０μｍと成長ＰＪみが薄く、基板収汲中に割れ易い
など作業性ら悪く、発光効率も低くなることすらあった
。(b) Techniques from UC Conventionally, liquid phase epitaxial growth of compound semiconductors, especially GaAρAs, has been carried out by the sliding method as disclosed in Japanese Patent Application Laid-Open No. 63-51624. A substrate (-Noeha'') (32) is placed, and the melt (341 (34)) is slid onto it to bring the upper surface of the substrate (32) into contact with the lower surface of the melt (34),
It is grown epitaxially by slow cooling. And especially G
a In the AρAs light emitting device, GaAs was used as the substrate (32), but the G = i ARAs growth layer was
The growth projector was thin at ~40 μm, and the workability was poor, such as being easily broken during substrate collection, and the luminous efficiency was even low.

例えば、実験によると、９５０°Ｃから６００℃までエ
ピタキシャル成長させると、第２図の点線（Ｄ）の如く
融液（３４）の厚みが２．　Ｃ）ｎｍまでは融液の厚み
に従って成長層の厚みも大きくなるが、それ以りは成長
Ｊ帽の厚みが大きくならず、高々１００μｍしか厚くな
らない。しかもこの傾向はＡρＡｓの混晶比が大きくな
ればなる程顕著となこれに対しＧ　ａ　Ａ　ｌｌ　Ａ　
ｓ層が厚くなると基板が割れ難くなるのに加え、Ｑ　ａ
　ＡρＡｓ基板として発光層形成ベースを構成したり、
　Ｇ　ａ　Ａ　（ｌ　Ａ　ｓ変成層（混晶比の不安定な
領域：ＧａＡｌＡｓ　　ｇｒａｄｅｄ　Ｉａ７ｅｒ）か
ら充分離れた所に発光層を形成したりできるので発光効
率も高くなる０本発明はこのようなＧａＡｇＡｓ成長層
を厚くする成長装置及び方法を提供するものである。For example, according to experiments, when epitaxial growth is performed from 950°C to 600°C, the thickness of the melt (34) increases by 2.5 mm, as shown by the dotted line (D) in FIG. C) The thickness of the grown layer increases with the thickness of the melt up to nm, but beyond that the thickness of the grown J cap does not increase and becomes only 100 μm at most. Moreover, this tendency becomes more pronounced as the mixed crystal ratio of AρAs increases.
The thicker the s layer, the more difficult it is for the substrate to break, and the Q a
The light emitting layer formation base is configured as an AρAs substrate,
Since the light emitting layer can be formed at a sufficient distance from the GaA (l As metamorphic layer (region with unstable mixed crystal ratio: GaAlAs graded Ia7er)), the light emitting efficiency can be increased. A growth apparatus and method for thickening a growth layer are provided.

（：）　＋１題を解決するための手段 本発明はウェハホルダとして化合物半導体の基板の成長
面を下方（引力方向）に向けて保持できる様に構成し、
そのウェハホルダと相対的に摺動できるメルトホルダは
化合物半導体の基板の下方露出面に融液（メルト）が接
するよう融液溜を設けたものである。(:) +1 Means for solving the problem The present invention is configured as a wafer holder so that the growth surface of a compound semiconductor substrate can be held downward (in the direction of attraction).
A melt holder that can slide relative to the wafer holder is provided with a melt reservoir so that the melt comes into contact with the lower exposed surface of the compound semiconductor substrate.

また本発明はＧａＡ、９Ａｓ又はＧａＡｓの基板の下面
にＧａを主体とする厚さ２．０ｍ以上の融液を接触させ
て徐冷しＧ　ａ　ＡｇＡｓ層を成長させるものである。Further, in the present invention, a GaAgAs layer is grown by bringing a Ga-based melt with a thickness of 2.0 m or more into contact with the lower surface of a GaA, 9As, or GaAs substrate and slowly cooling the melt.

（ホ）作　用 これによりＧ　ａ　ＡｇＡ　ｓ　ｆｍは１００μｍ以上
の厚みに成長する。この理由は明確ではないが表１夜中
において結晶種がＧａ液に対し軽く、上方に移動しやす
く、これによってＧ　ａ　ＡρＡｓ成長別界面に必要な
混晶比の結晶種が補充されやすいものと推測される。(e) Effect As a result, GaAgAs fm grows to a thickness of 100 μm or more. The reason for this is not clear, but it is assumed that the crystal seeds in Table 1 are lighter than the Ga liquid during the night and move upwards, which makes it easier to replenish the crystal seeds with the required mixed crystal ratio at the interface for each Ga AρAs growth. be done.

（へ）実施例 第１図は本発明実施例の液相エピタキシャル成長装置の
模式図で、（１）はＧ　ａ　ＡｇＡｓ又はＧ　ｉｌ’Ｌ
Ａｓの化合物半導体からなる基板（２）を収納するウェ
ハホルダで、基板（２）の下側を成長面とし、その下側
面を露出するよう四部が設けてあり、この凹部にＧａ液
液等粘着材料で基板（２）が貼１寸しである。（３）は
ウェハホルダ＋１１と相対的に１８動できるように積層
されたメルトホルダで、これらのホルダ（＋１１３＋は
共に黒鉛製スライドボート等からなる。そしてメルトホ
ルダ（３）はエピタキシャル成長時に基板（２）の下方
露出部に融液（４）が接触するように融液溜（四部）を
有し、この融液溜の深さは後述する様に２．０ｆｆｌｌ
Ｉ＋以上ある。従ってメルトホルダ（３）を上下２層と
し、準備された融液の一部をエピタキシャル成長に用い
る場合も、エピタキシャル成長に直接寄与する融液の励
みが２゜Ｃ）ｍ＋以上となる様に構成する。(f) Example FIG. 1 is a schematic diagram of a liquid phase epitaxial growth apparatus according to an example of the present invention.
A wafer holder that stores a substrate (2) made of an As compound semiconductor.The lower side of the substrate (2) is used as a growth surface, and four parts are provided to expose the lower side. The board (2) is 1 inch thick. (3) is a melt holder stacked so that it can move relative to the wafer holder +11, and these holders (+113+ are both made of graphite slide boats, etc.).The melt holder (3) is placed under the substrate (2) during epitaxial growth. A melt reservoir (4 parts) is provided so that the melt (4) comes into contact with the exposed part, and the depth of this melt reservoir is 2.0 ffll as described later.
There is more than I+. Therefore, even when the melt holder (3) has two layers, upper and lower, and a part of the prepared melt is used for epitaxial growth, it is constructed so that the excitation of the melt that directly contributes to epitaxial growth is 2°C)m+ or more.

この様な構成において、ＧａＡｓの基板（２）にＡｇＡ
ｓの混晶比０．６〜０．７のＧａＡｌＡｓ層を成長させ
る時のエピタキシャル成長工程を説明する。まず、融液
（４）はＧａ１００ｇにＧａＡＳを６ｇ、Ａ＃を６００
ｍｇ、Ｚｎを６００ｍｇ混入して準備する。そして基板
（２）と融液（４）を分離した状態で８６０〜９５０℃
の所定の温度で約１時間保持する。その後ウェハホルダ
（１１を摺動させて基板（２）の下方露出面と融液（４
）上面とを接触させ、必要とあればメルトバックして、
そのｆ＆０゜５〜３　”／Ｉ＋１１　ｍの所定の温度勾
配で徐冷することによりエピタキシャル成長させ、６０
０−７００℃の所定の温度に達したところで成長をやめ
る。In such a configuration, AgA is applied to the GaAs substrate (2).
The epitaxial growth process for growing a GaAlAs layer with an s mixed crystal ratio of 0.6 to 0.7 will be described. First, melt (4) contains 100 g of Ga, 6 g of GaAS, and 600 g of A#.
Prepare by mixing 600 mg of Zn. Then, the substrate (2) and the melt (4) were heated to 860 to 950°C in a state where they were separated.
The sample is maintained at a predetermined temperature for about 1 hour. Thereafter, the wafer holder (11) is slid to connect the lower exposed surface of the substrate (2) with the melt (4).
) Contact the top surface, melt back if necessary,
Epitaxial growth was performed by slow cooling at a predetermined temperature gradient of f&0°5~3''/I+11 m.
Growth stops when a predetermined temperature of 0-700°C is reached.

この様にして形成されたＧａＡρＡｓエピタキシャル成
長層の厚みは、第２図に実線（Ａ）で示す如く融；は（
４）の厚みがＪゾくなればなる程成長層が厚くなった。The thickness of the GaAρAs epitaxial growth layer formed in this way is as shown by the solid line (A) in FIG.
The more the thickness of 4) becomes J, the thicker the growth layer becomes.

ウェハの取扱い易さ、エピタキシャル成長層の結晶均一
性から、（、’ｔａＨ−、ＡρＸＡｓの混晶比Ｘが比較
的高い場合、例えば０．６Ｋｘ、ｐｏ、８では融液厚み
は３〜７−がよい。−方混晶比が低くなると成長しやす
くなるが、同図破線（［））に示す如く、発光素子とし
て実用的な低混晶比ｘ＝０．４５〜０．５０において１
００μｍ以」−の成長層のＪヴみを得るには、Ｍ液の）
％（さは２．０ｍ以上必要である。Considering the ease of handling the wafer and the crystal uniformity of the epitaxially grown layer, (,'taH-, When the mixed crystal ratio X of Aρ Good. The lower the negative mixed crystal ratio, the easier the growth will be, but as shown by the broken line ([) in the figure, at a low mixed crystal ratio x = 0.45 to 0.50, which is practical for light emitting devices, 1
To obtain a JV of a growth layer of 00 μm or more, use M solution)
% (The height must be at least 2.0 m.

また、先の高混晶比の例において、Ｍ液の上下に基板（
２）を配置すると、上側に配置した基板において成長層
の厚みは第２図−転鎖線（Ｃ）の如く、融滴下面に基板
をおいた時にみられた成長層Ｊヴの飽和現象はなくなっ
たが成長の厚さの仲ひは鈍くなった。In addition, in the above example of a high mixed crystal ratio, the substrates (
2), the thickness of the growth layer on the upper substrate becomes as shown in Figure 2 - dashed line (C), and the saturation phenomenon of the growth layer JV that was observed when the substrate was placed on the lower surface of the molten drop disappeared. However, the relationship between the thickness of growth has slowed down.

（ト）音用の効果 以上の如くにより、成長しにくいとされたＧ　ａＡＱＡ
ｓＪＭを充分な厚みとすることができたので、ウェハの
取板が容易となり、また混晶比等が結晶特性が安定する
まで成長させることができるので発光効率５０〜７５％
の発光ダイオードを得ることができた。(g) GaAQA, which is said to be difficult to grow due to more than just its sound effects.
Since we were able to make the sJM sufficiently thick, it was easy to remove the wafer, and the mixed crystal ratio etc. could be grown until the crystal properties were stabilized, resulting in a luminous efficiency of 50 to 75%.
We were able to obtain a light emitting diode.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明実施例の液相エピタキシャル成長装置の
模式図、第２図はエピタキシやル成尺層ダ、（４）・・
・融液。Fig. 1 is a schematic diagram of a liquid phase epitaxial growth apparatus according to an embodiment of the present invention, and Fig. 2 is a schematic diagram of a liquid phase epitaxial growth apparatus according to an embodiment of the present invention.
- Melt liquid.

Claims (1)

【特許請求の範囲】 １）化合物半導体の基板を下方に露出させて収納保持す
るウェハホルダと、該ウェハホルダと摺動自在に組合わ
され、エピタキシャル成長時に前記基板の下方露出部に
融液が接触する様融液溜を具備したメルトホルダとを具
備してなる液相エピタキシャル成長装置。 ２）ＧａＡｌＡｓ又はＧａＡｓの基板の下面にＧａを主
体とする厚さ２．０ｍｍ以上の融液を接触させた後徐冷
してＧａＡｌＡｓ層を液相エピタキシャル成長させる事
を特徴とする液相エピタキシャル成長方法。[Scope of Claims] 1) A wafer holder that accommodates and holds a compound semiconductor substrate exposed downward, and a wafer holder that is slidably combined with the wafer holder so that the melt contacts the downwardly exposed portion of the substrate during epitaxial growth. A liquid phase epitaxial growth apparatus comprising a melt holder equipped with a liquid reservoir. 2) A liquid phase epitaxial growth method, characterized in that a GaAlAs layer is grown by liquid phase epitaxial growth by bringing a Ga-based melt with a thickness of 2.0 mm or more into contact with the lower surface of a GaAlAs or GaAs substrate and then slowly cooling the liquid.