JPS6067672A - Electric furnace - Google Patents

Abstract

PURPOSE:To obtain a small gaseous phase growing electric furnace having a steep temp. gradient, in an electric furnace having two or more of regions different in a temp. condition, by providing a forcibly cooling heat absorbing region between two regions. CONSTITUTION:A heat absorbing region C is provided between a high temp. region A heated by a heat generator 31 and a low temp. region B heated by a heat generator 32. A pipe 35 having an inlet 36 and an outlet 37 for supplying and discharging a cooling medium is provided in the spacer 33 interposed between the heat generators 31, 32 and a cooling fluid is forcibly sent into said pipe 35 by a pump. Because excessive heat flowing out from the region A is entirely absorbed with the region C and carried out of an electric furnace through the cooling fluid, influence upon the region B is eliminated and a steep temp. gradient is obtained. Because the length of the region C (the distance between the regions A, B) becomes short, the dimension of the electric furnace can be shortened to a large extent.

Description

【発明の詳細な説明】 本発明は気相成長用として要求されるきわめて急激な温
度勾配を含む温度分布を実現した電気炉に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric furnace that achieves a temperature distribution including an extremely steep temperature gradient required for vapor phase growth.

半導体、特にＧａＡｓに代表される■−ｖ族化合物半導
体の気相成長においては、少なくとも二つの温度条件の
異なる領域を持ち、さらにそれぞれの領域で一定の長さ
の平坦温度領域のある電気炉が必要である。すなわち、
■族元素と■族元素の塩化物を出発原料とするクロライ
ド法気相成長法では、■族元素をソースとして反応管内
の高温領域に設置し、この領域にキャリアガスと共に■
族元素の塩化物を送入して反応させ、反応管内の下流低
温領域に置かれた基板上に結晶を析出させるものである
。自とＡｓＣＪｓとを用いるＧａＡｓの成長では、＠ソ
ースおよび基板の温度はそれぞれ８５０℃および７５０
℃前後とするのが一般的である。′ｊだ、ＩＩＩ族元素
と塩化水素とを反応させて■１族元素の１！（化物を高
温に保たれた反応管上流部で作り、■族元素を水素化物
として供給して両者を反応させ、反応管内の下流低温領
域に置かれた基板上に結晶を析出させるハイドライド法
気相成長Ｃも二つの温度条件の異なる領域を用いるのが
一般的である。In the vapor phase growth of semiconductors, especially ■-V group compound semiconductors represented by GaAs, an electric furnace is used that has at least two regions with different temperature conditions, and each region has a flat temperature region of a constant length. is necessary. That is,
In the chloride vapor phase growth method, which uses group ■ elements and chlorides of group
A chloride of a group element is introduced and reacted, and crystals are deposited on a substrate placed in a downstream low-temperature region within the reaction tube. For GaAs growth using AsCJs and AsCJs, @source and substrate temperatures were 850°C and 750°C, respectively.
Generally, it is around ℃. 'j, by reacting a group III element with hydrogen chloride ■ 1 of the group 1 element! (A hydride method in which a compound is made in the upstream part of a reaction tube kept at a high temperature, a group III element is supplied as a hydride, the two are reacted, and crystals are precipitated on a substrate placed in a downstream low temperature region of the reaction tube. Phase growth C also generally uses two regions with different temperature conditions.

また、伽とＨＣＩ　、　ＡｇＨ，を用いるＧａＡｓの成
長では、自ソースおよび基板の温度はそれぞれ９００°
Ｃおよび７５０℃前後を用いるのが適当である。In addition, in the growth of GaAs using Ga, HCI, AgH, the temperature of the source and substrate is 900°, respectively.
It is appropriate to use temperatures around 750°C and 750°C.

従来の、複数の温度条件の異なる領域を持つ電気炉では
、相隣り合う設定温度条件の異なる２つの温度領域の間
の温度勾配はあまり大きくとることができない、二つの
温度領域間の距離合小さくし、温度差を大きくしようと
しても、高温領俄からの熱の影響のために低温領域の高
温領域に近い側は発熱体への久方パワーをいかに小さく
してもある温度以下にはならない。したがって、温度差
を大きくするためには二つの温度領域間の距離を遠ざけ
、さらに中間に両者間の熱的な相互作業を断つ、断熱領
域を設けることが必要である。In conventional electric furnaces that have multiple regions with different temperature conditions, the temperature gradient between two adjacent temperature regions with different set temperature conditions cannot be very large, and the distance between the two temperature regions is small. However, even if an attempt is made to increase the temperature difference, due to the influence of heat from the high-temperature region, the temperature on the side of the low-temperature region near the high-temperature region will not drop below a certain level no matter how small the power applied to the heating element is. Therefore, in order to increase the temperature difference, it is necessary to increase the distance between the two temperature regions and to provide an insulating region in the middle that cuts off thermal interaction between the two regions.

反応管の直径が６０　ｍｚ前後と小さく、したがって電
気炉の口径が小さい場合は比較的温度勾配が大きくとれ
るため電気炉長も小さくて済んだが、近年の半導体デバ
イスの需要増加に伴なう気相成長装置の大型化、大口径
化によってこの温度勾配を大きくできないのが重大な問
題となってきた。例えば、電気炉の口径が１８０＊ｒｔ
ｔ程度となると温度勾配を０・３℃／間以上とするのは
困州であるため、１５０℃の温度差をつけるには二つの
温度領域の間に５００ｍｙｔ以上の断熱領域が必要とな
る。このだめ電気炉の全長は２ｍ前後と長くなシ、こＪ
ｌ、に伴って反応管の寸法も無駄に長くなり、また基板
ローダ等の＋１に設備も大きなものとなって、装置全体
が大型化し、当然に高価なものとなってしまう。If the diameter of the reaction tube is small, around 60 mz, and the diameter of the electric furnace is small, the temperature gradient can be relatively large and the length of the electric furnace can be shortened, but with the recent increase in demand for semiconductor devices, the gas phase The inability to increase this temperature gradient has become a serious problem as growth apparatuses become larger and have larger diameters. For example, the diameter of the electric furnace is 180*rt
Since it is difficult to maintain a temperature gradient of 0.3°C or more when the temperature reaches about t, an adiabatic area of 500 myt or more is required between two temperature areas to create a temperature difference of 150°C. The total length of this electric furnace is around 2m, which is long.
1, the dimensions of the reaction tube become unnecessarily long, and additional equipment such as a substrate loader becomes large, making the entire apparatus large and naturally expensive.

不発開拡、従来の電気炉における上記の欠点を取り除き
、二つの温度領域間の距離を小さくしても十分大きな温
度差が得られる電気炉を提供することを目的とするもの
である。The object of this invention is to eliminate the above-mentioned drawbacks of conventional electric furnaces and to provide an electric furnace that can obtain a sufficiently large temperature difference even if the distance between two temperature regions is reduced.

すなわち、本発明は、二つ以上の温度条件の異なる領域
を有する電気炉において、発熱体にて加熱される設定温
度条件の異なる温度領域間に、冷却用流体の送入によシ
強制的に冷却する熱吸収領域を設けたことを特徴とする
電気炉である。That is, in an electric furnace having two or more regions with different temperature conditions, the present invention is capable of forcibly introducing a cooling fluid between the temperature regions heated by a heating element and having different set temperature conditions. This electric furnace is characterized by being provided with a heat absorption area for cooling.

以下図面を用いて本発明の実施例を詳しく説明する。第
１図（ａ）は通常の二つの温度条件の異なる領域を持つ
電気炉であり、発熱体１１で加熱される高温領域（温度
ＴＩ）と、発熱体１２で加熱される低温領域（温度Ｔ、
あるいはＴ、）とがある。両者の温度差ΔＴ＝Ｔｓ　−
Ｔ鵞が小さい場合は第１図（ｂ）に示した温度分布の実
線のように必要な温度分布が得られるが、低温領域をＴ
３とさらに低くしようとしても、同図破線に示したよう
に平坦な温度領域が得られない。これは、初めに述べた
ようＫ、高温領域からの熱が低温領域へ流れてくるため
である。Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1(a) shows an ordinary electric furnace having two regions with different temperature conditions: a high temperature region (temperature TI) heated by a heating element 11, and a low temperature region (temperature T) heated by a heating element 12. ,
Or T, ). Temperature difference between the two ΔT=Ts −
If T is small, the necessary temperature distribution as shown in the solid line of the temperature distribution shown in Figure 1(b) can be obtained, but if the low temperature region is
Even if an attempt is made to lower the temperature to 3, a flat temperature region cannot be obtained as shown by the broken line in the figure. This is because, as mentioned at the beginning, heat from the high temperature region flows to the low temperature region.

第２図（ａ）　Ｕ十分に大きな温度差を得るために、二
つの温度条件の異なる領域間の距離を大きくし、さらに
中間に相互の熱的影響を減少させる断熱領域２３を設け
たものである。この方法によって第２図（ｂ）に示した
ように必要な温度分布を得ることが可能となるが、電気
炉の長さは口径の増加に伴って急激に長くなる。仁のこ
とが多くの問題を引き起こすのはすでに述べた通シであ
る。Figure 2 (a) U In order to obtain a sufficiently large temperature difference, the distance between two regions with different temperature conditions is increased, and an insulating region 23 is provided in the middle to reduce mutual thermal influence. be. Although this method makes it possible to obtain the necessary temperature distribution as shown in FIG. 2(b), the length of the electric furnace increases rapidly as the diameter increases. It is the above-mentioned Toushi that causes many problems with Jin.

第３図（ａ）は本発明の一実施例を示す。本発明は、要
するに電気炉内の必要な部分を積極的に強制冷却して温
度分布を制御しようとするものである。FIG. 3(a) shows an embodiment of the present invention. In short, the present invention attempts to control the temperature distribution by actively forced cooling of necessary portions within the electric furnace.

従来の電気炉には加熱するだめの発熱体のみが設けられ
ており、この発熱体の発生熱量を制御して所要の温度分
布をｊ予ており、冷却に関しては発熱体のない部分を設
けてそこが自然に冷却されるのを利用したり、発熱体外
側の断熱材の量を変えたりしていたにすぎなかったため
、その冷却能力は小さなものであり、急激な温度勾配を
得ることは不可能であった。これに対し、本発明では冷
却用つた熱を外部に取り出せるので、急激な温度勾配を
含め、温度分布の自由度が飛曜的に大きくなる。Conventional electric furnaces are equipped with only a heating element for heating, and the amount of heat generated by this heating element is controlled to achieve the desired temperature distribution.For cooling, a section without a heating element is provided. The only way to do this was to take advantage of the natural cooling of the heating element or change the amount of insulation on the outside of the heating element, so its cooling capacity was small and it was impossible to obtain a sharp temperature gradient. It was possible. In contrast, in the present invention, the heat used for cooling can be taken out to the outside, so the degree of freedom in temperature distribution, including rapid temperature gradients, is dramatically increased.

第３図（ａ）において、発熱体３１で加型Ｓさｔｒ、る
高温領域Ａと、発熱体３２で加熱される低温領域Ｂとの
間に熱吸収領域Ｃを設ける。具体的にシ、シ、両売−１
ｈ体３１　、３２間に介在させたスペーサ３３内に冷却
用流体を給排する入口３６、出口３７をもつバイブ３５
を設け、この巾に冷却用流体をポンプ等で９．；ｌｉ制
的に送入するものである。冷却用流体としでし、１−水
、油、窒素ガスなどを用いる。このようにすると高温領
域から流れ出る余分な熱は、すべて熱吸収領域で吸収さ
れ、冷却用流体を通して電気炉外−％　、ｉｌｌげｉす
るのて、低温領域への影響がなくなり、第３トイｌ　（
＋））に示すように急激な温度勾配が得らノ；、る。木
４ら明によれば、先に述べた口径１８０ｍｍの炉でも、
１５０’Ｃの温度差を５０間の熱吸収領域で実現でき、
電気炉の寸法を大幅に短縮することが可能でちる。以上
のように、不発ｌ３ＡＶＣよって大口径でかつ急激な温
度勾配を持つ電気炉が得られるため、電気炉本体の寸法
がｌト貞（たＡだけでたｌとＪ〕Ｉｙ　ｌにリイ曲醐（
・へ周辺装置を含め気相成長装置全体の犬＠な小型化、
低価格化が可能となる。また、小型化、低価格化のみで
なく、従来得られなかった５℃４？ｌといった大きな温
度勾配を利用することによって新たな応用が可能になる
などの効果を有するものである。In FIG. 3(a), a heat absorption region C is provided between a high temperature region A heated by a heating element 31 and a low temperature region B heated by a heating element 32. In FIG. Specifically, shi, shi, ryouri-1
A vibrator 35 having an inlet 36 and an outlet 37 for supplying and discharging cooling fluid into a spacer 33 interposed between the h bodies 31 and 32.
9. Provide cooling fluid to this width using a pump, etc. ;It shall be sent on a li basis. As a cooling fluid, 1-water, oil, nitrogen gas, etc. are used. In this way, all the excess heat flowing out from the high temperature area is absorbed in the heat absorption area, and is passed through the cooling fluid to the outside of the electric furnace, so that it has no effect on the low temperature area, and the third toilet (
As shown in +)), a sharp temperature gradient cannot be obtained. According to Ki 4 Ramei, even with the furnace with a diameter of 180 mm mentioned earlier,
A temperature difference of 150'C can be achieved in a heat absorption area of 50°C,
It is possible to significantly shorten the dimensions of the electric furnace. As mentioned above, since an electric furnace with a large diameter and a steep temperature gradient can be obtained using unexploded 13AVC, the dimensions of the electric furnace body can be changed to (
- Miniaturization of the entire vapor phase growth equipment including peripheral equipment,
This makes it possible to lower prices. In addition to being smaller and lower in price, we have also achieved a temperature of 5℃4, which was previously unobtainable. This has the effect of making new applications possible by utilizing a large temperature gradient such as 1.

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

（ｂ）はその温度分布図である。 ３１は高温領域用発熱体、３２は低温領域用発熱体、３
３はスペーサ、３４は断熱材、３５は冷却用流体の流れ
るパイプ、３６は冷却用流体の入口、３７は同出口、Ａ
は高温領域、Ｂは低温領域、Ｃは熱吸収領域である。 特許出願人　日本電気株式会社 第１図　− （ｂ） 距離 第２図 （ｂ） 距離 第３図 （ｂ） （−一−１−一一ノー一） ＡＣＢ　距離(b) is the temperature distribution map. 31 is a heating element for high temperature region, 32 is a heating element for low temperature region, 3
3 is a spacer, 34 is a heat insulating material, 35 is a pipe through which cooling fluid flows, 36 is an inlet for cooling fluid, 37 is an outlet thereof, A
is a high temperature region, B is a low temperature region, and C is a heat absorption region. Patent applicant NEC Corporation Figure 1 - (b) Distance Figure 2 (b) Distance Figure 3 (b) (-1-1-11-no-1) ACB distance

Claims (1)

【特許請求の範囲】[Claims] （す二つ以上の温度条件のｎなる領域を有する電気炉に
おいて、発熱体で加熱される設定温度条件の異なる互い
に面接した二つの温度領域の中間に、冷却用流体を送入
して強制的に冷却する熱吸収領域を設けたことを特徴と
する電気炉。(In an electric furnace having n regions with two or more temperature conditions, a cooling fluid is forced into the middle of two temperature regions facing each other with different set temperature conditions heated by a heating element. An electric furnace characterized by having a heat absorption area for cooling.