【考案の詳細な説明】 ［産業上の利用分野］ 本考案は、化合物半導体単結晶製造装置、特にガリウム
・ヒ素半導体単結晶製造装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a compound semiconductor single crystal manufacturing apparatus, and more particularly to a gallium arsenide semiconductor single crystal manufacturing apparatus.

［従来の技術］ ガリウム・ヒ素（ＧａＡｓ）半導体等、化合物半導体の
単結晶を成長させる場合は各種の方式が用いられるがそ
のうち一つに帯域溶融方式がある。[Prior Art] When growing a single crystal of a compound semiconductor such as a gallium arsenide (GaAs) semiconductor, various methods are used, and one of them is a zone melting method.

第４図はＧａＡｓ単結晶の成長に用いられる帯域溶融装
置の断面図を示すもので１は石英管、２は石英ボート、
３は溶融前のＧａＡｓ、４はＧａＡｓの融液帯、５は種
結晶、６はヒ素（Ａｓ）、７は高温炉、８は融液帯４を
形成する融液形成炉、９は固液界面の温度を制御する界
面制御炉、１０はＡｓ加熱する低温炉である。FIG. 4 shows a sectional view of a zone melting apparatus used for growing a GaAs single crystal, 1 is a quartz tube, 2 is a quartz boat,
Reference numeral 3 is GaAs before melting, 4 is a melt zone of GaAs, 5 is a seed crystal, 6 is arsenic (As), 7 is a high temperature furnace, 8 is a melt forming furnace for forming the melt zone 4, and 9 is a solid solution. An interface control furnace 10 that controls the temperature of the interface is a low temperature furnace that heats As.

同図において石英管１内の一端にＧａ２０００ｇと種結
晶５を入れた石英ボート２を配置し、他端にはＡｓ２２
００ｇを配置して石英管１内を５×１０^-6Torr以下の圧
力で１時間以上真空に吸引して封じ切り、ついで低温炉
１０の温度を６１０℃、高温炉７の温度を１２００℃に
すると低温炉１０側に配置されているＡｓが蒸発して石
英管１の内部圧力がＡｓの蒸気圧となりこの状態でＧａ
Ａｓの合成反応が行われる。次に融液形成炉８の温度を
１２６０℃に上昇させるとＧａＡｓの一部が溶融して融
液帯（融液ゾーン）４が形成される。In the figure, a quartz boat 2 containing Ga2000g and a seed crystal 5 is arranged at one end in a quartz tube 1, and As22 is arranged at the other end.
00g is placed and the inside of the quartz tube 1 is sucked into a vacuum at a pressure of 5 × 10 ⁻⁶ Torr or less for 1 hour or more to seal off, and then the temperature of the low temperature furnace 10 is set to 610 ° C. Then, As arranged on the low temperature furnace 10 side evaporates, and the internal pressure of the quartz tube 1 becomes the vapor pressure of As.
A synthetic reaction of As is performed. Next, when the temperature of the melt forming furnace 8 is raised to 1260 ° C., a part of GaAs is melted to form a melt zone (melt zone) 4.

第２図はＧａＡｓ溶融時の温度分布を示すもので横軸が
融液帯の位置Ｘ、縦軸が炉内温度（Ｔ℃）を示す。上述
の場合の温度特性は同図曲線Ａに示すようになり、この
時のＧａＡｓ融液帯幅は１００〜２００mm、成長速度は
２〜７mm／時で単結晶の成長が行われた。FIG. 2 shows the temperature distribution when GaAs is melted. The horizontal axis shows the melt zone position X, and the vertical axis shows the temperature in the furnace (T ° C.). The temperature characteristics in the above case are as shown by the curve A in the figure. At this time, the single crystal was grown at a GaAs melt zone width of 100 to 200 mm and a growth rate of 2 to 7 mm / hour.

［考案が解決しようとする課題］ 上述したように第４図に示す装置を用いてＧａＡｓ単結
晶の成長を行なわせた結果温度特性は第３図曲線Ａに示
すようになり温度勾配が比較的大きいことが示されてい
るが、これは融液形成炉８の熱が界面制御炉９の方へ流
れたため固液界面近傍における温度勾配が大きくなった
ためで、これにより融液の対流が増大して固液界面が融
液側へ凹凸となり良好なＧａＡｓ単結晶の成長を防げる
現象が生じた。[Problems to be Solved by the Invention] As a result of growing a GaAs single crystal by using the apparatus shown in FIG. 4 as described above, the temperature characteristic is as shown by the curve A in FIG. 3 and the temperature gradient is relatively large. Although it is shown that the temperature is large, this is because the heat of the melt forming furnace 8 flows toward the interface control furnace 9 and the temperature gradient near the solid-liquid interface becomes large, which increases the convection of the melt. As a result, the solid-liquid interface became uneven toward the melt, and a phenomenon that prevented good growth of GaAs single crystal occurred.

本考案の目的は、融液形成炉より界面制御炉へ流れる熱
の移動を防止し、固液界面を安定にして高純度単結晶の
成長を行わせる化合物半導体単結晶製造装置を提供する
ことにある。An object of the present invention is to provide a compound semiconductor single crystal production apparatus which prevents the heat flowing from the melt forming furnace to the interface control furnace and stabilizes the solid-liquid interface to grow a high-purity single crystal. is there.

［課題を解決するための手段］ 本考案は融液形成炉と界面制御炉との間に、融液形成炉
より界面制御炉へ放射される熱移動を防止して固液界面
を安定化させ単結晶を高純度に成長させる熱輻射遮蔽板
が設けてあることを特徴としており、高品質の単結晶が
得られるようにして目的の達成を計っている。[Means for Solving the Problems] The present invention stabilizes the solid-liquid interface by preventing heat transfer from the melt forming furnace to the interface controlling furnace between the melt forming furnace and the interface controlling furnace. It is characterized by the provision of a heat radiation shielding plate for growing a single crystal with high purity, and the aim is to achieve a high quality single crystal.

［作用］ 本考案の化合物半導体単結晶製造装置では帯域溶融装置
を用いてＧａＡｓの単結晶を成長させる場合、ＧａＡｓ
の融液ゾーンを形成する融液形成炉と融液ゾーンと接す
る固液界面の温度を制御する界面制御炉との間に熱輻射
遮蔽板を取付け、融液形成炉から界面制御炉へ放射され
る熱移動を防止するようにしているので、固液界面にお
ける温度傾斜が緩やかとなり、高純度の単結晶を安定に
成長させることができる。[Operation] In the compound semiconductor single crystal production apparatus of the present invention, when a GaAs single crystal is grown using the zone melting apparatus,
The heat radiation shield plate is installed between the melt forming furnace that forms the melt zone and the interface control furnace that controls the temperature of the solid-liquid interface in contact with the melt zone, and is radiated from the melt forming furnace to the interface control furnace. Since the heat transfer is prevented, the temperature gradient at the solid-liquid interface becomes gentle and a high-purity single crystal can be stably grown.

［実施例］ 以下、本考案の一実施例について図を用いて説明する。
第１図は本考案の化合物半導体単結晶製造装置の一実施
例を示す断面図、第２図は第１図を側方よりみた側面断
面図である。これらの図は第４図の場合と殆ど同一のも
のであるが異なるのは熱輻射遮蔽板１１が設けられてい
る点にある。[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of the compound semiconductor single crystal manufacturing apparatus of the present invention, and FIG. 2 is a side sectional view of FIG. 1 seen from the side. Although these figures are almost the same as the case of FIG. 4, the difference is that the heat radiation shielding plate 11 is provided.

本実施例の場合は熱輻射遮蔽板１１を設けたことにより
融液形成炉８から界面制御炉９へ放射される輻射熱が遮
断される結果、温度特性は第３図曲線Ｂに示すようにな
り、固液界面Ｘ_０における温度傾斜が０．５℃／cmと同
図曲線Ａの場合の１℃／cmに比べて１／２に減少し、固
液界面が融液側に凸面となり、高純度単結晶を得ること
ができた。この場合得られたＧａＡｓ単結晶はＧａ、Ａ
ｓの量等第４図の場合と同一条件において４．１kgであ
って種結晶側及び結晶尾部とも転位密度が１０^４cm^-2以
下の低転位結晶を得ることができた。In the case of the present embodiment, by providing the heat radiation shield plate 11, the radiant heat radiated from the melt forming furnace 8 to the interface control furnace 9 is cut off, so that the temperature characteristic becomes as shown by the curve B in FIG. The temperature gradient at the solid-liquid interface X ₀ is 0.5 ° C / cm, which is 1/2 of 1 ° C / cm in the case of the curve A in the figure, and the solid-liquid interface becomes convex on the melt side. A pure single crystal could be obtained. The GaAs single crystal obtained in this case is Ga, A
Under the same conditions as in FIG. 4, the amount of s was 4.1 kg, and a low dislocation crystal having a dislocation density of 10 ⁴ cm ⁻² or less on both the seed crystal side and the crystal tail could be obtained.

尚熱輻射遮蔽板の材質としては断熱材が用いられるが、
この他炭化ケイ素（ＳｉＣ）、酸化アルミニウム（Ａｌ
_２Ｏ_３）、アジ化アルミニウム（ＡｌＮ）等のセラミッ
クスを用いてもよい。A heat insulating material is used as the material of the heat radiation shielding plate,
In addition, silicon carbide (SiC), aluminum oxide (Al
₂ O ₃ ), ceramics such as aluminum azide (AlN) may be used.

又、水冷機能付きの冷却板を用いるのが最も良く固液界
面付近の温度勾配を殆ど零とすることができ、極めて安
定な界面を形成することができる。Further, it is best to use a cooling plate having a water cooling function, since the temperature gradient near the solid-liquid interface can be made almost zero, and an extremely stable interface can be formed.

［考案の効果］ 以上述べたように本考案によれば次のような効果が得ら
れる。[Effect of the Invention] As described above, according to the present invention, the following effects can be obtained.

(1)熱輻射遮蔽板を用いることによりＧａＡｓ単結晶成
長時における固液界面を安定化させ高純度の単結晶を得
ることができる。(1) By using a heat radiation shield plate, the solid-liquid interface can be stabilized during the growth of GaAs single crystal, and a high-purity single crystal can be obtained.

(2)水平ブリッジマン方式（ＨＢ方式）や温度傾斜方式
（ＧＦ方式）に比べ結晶の長さ方向に均一な濃度を有す
るドーパント分布を得ることができ、各ウエハ間の特性
のバラツキを低減することができる。(2) As compared with the horizontal Bridgman method (HB method) and the temperature gradient method (GF method), it is possible to obtain a dopant distribution having a uniform concentration in the crystal length direction, and reduce variations in characteristics between wafers. be able to.

(3)クローム（Ｃｒ）をドープした結晶のように偏析係
数の小さなドーパントを使用する場合は特に有効に適用
することができる。(3) It can be applied particularly effectively when a dopant having a small segregation coefficient is used such as a crystal doped with chrome (Cr).

第１図は本考案の化合物半導体単結晶製造装置の一実施
例を示す帯域溶融装置の断面図、第２図は第１図の側面
断面図、第３図は温度分布特性図、第４図は従来装置の
断面図である。 １：石英管、 ２：石英ボート、 ３：ＧａＡｓ、 ４：融液ゾーン、 ５：種結晶、 ６：Ａｓ、 ７：高温炉、 ８：融液形成炉、 ９：界面制御炉、 １０：低温炉、 １１：熱輻射遮蔽板。FIG. 1 is a sectional view of a zone melting apparatus showing an embodiment of the compound semiconductor single crystal production apparatus of the present invention, FIG. 2 is a side sectional view of FIG. 1, FIG. 3 is a temperature distribution characteristic diagram, and FIG. FIG. 4 is a cross-sectional view of a conventional device. 1: Quartz tube, 2: Quartz boat, 3: GaAs, 4: Melt zone, 5: Seed crystal, 6: As, 7: High temperature furnace, 8: Melt forming furnace, 9: Interface control furnace, 10: Low temperature Furnace, 11: heat radiation shielding plate.