JPH0697076A - Vapor growth method of thin film - Google Patents

Abstract

PURPOSE:To make it possible to select a material according to a set substrate temperature and increase an operating efficiency of the material and further improve a quality of a thin film crystal, by growing a thin film using a plurality of materials having different decomposition temperature as the material for supplying the same element. CONSTITUTION:In a thin film growth, a plurality of material having different decomposition temperatures are used as the material for supplying the same element. For example, the material together with a hydrogen carrier is supplied from a piping 1 for supplying the material and a cleaning of a GaAs substrate 3 increased to a temperature of 700omicronC is performed by a heater 4. Then, (CH3)3Ga(TMG) is supplied and a GaAs buffer layer is grown. (CH3)3 In and TMG are supplied to the buffer layer and a P material is mixed with (CH3)3 CPH2 and CH3PH2 and is supplied at the ratio of V to III equal to 30. An InGaP growth film obtained in this manner is a mirror plane and has good electro-optic characteristics.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は薄膜成長のための有機金
属気相成長法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal organic chemical vapor deposition method for growing a thin film.

【０００２】[0002]

【従来の技術】たとえば、化合物薄膜の有機金属気相成
長法において基板温度は原料分子の分解のためと成長す
なわち、安定な結晶構造を作るために必要である。前者
と後者でそれぞれに適切な温度が存在する。両者の温度
が一致したときには、その温度に基板温度を設定すれば
良いが、一般には上記二つの温度は一致しない。この時
にはどちらかを犠牲にしなければならない。たとえば、
結晶構造すなわち膜質を重んずれば原料の供給比（III
−Ｖ族化合物の場合はＶ／III比）を著しく大きくしな
ければならず、多い方の原料の大半は膜成長に寄与しな
くては無駄になる、すなわち原料の使用効率が低くな
る。逆に原料の分解すなわち原料間の反応を重視すれば
結晶欠陥が多くなって膜質は必ずしも良くはならない。2. Description of the Related Art For example, in metalorganic vapor phase epitaxy of a compound thin film, the substrate temperature is necessary for decomposition of raw material molecules and for growth, that is, for forming a stable crystal structure. There is an appropriate temperature for each of the former and the latter. When the two temperatures match, the substrate temperature may be set to that temperature, but generally, the two temperatures do not match. At this time, either one must be sacrificed. For example,
If the crystal structure, that is, the film quality is emphasized, the feed ratio of the raw materials
In the case of a group-V compound, the V / III ratio) must be made extremely large, and most of the larger raw materials are wasted unless they contribute to film growth, that is, the raw material usage efficiency decreases. Conversely, if the decomposition of the raw materials, that is, the reaction between the raw materials is emphasized, the number of crystal defects increases and the film quality is not necessarily improved.

【０００３】したがって、これまで原料の分解や反応と
結晶成長の両者から見て最適の基板温度に設定すること
ができなかった。Therefore, it has been impossible to set the optimum substrate temperature in view of both decomposition and reaction of raw materials and crystal growth.

【０００４】[0004]

【発明が解決しようとする課題】上記のように結晶成長
から見て最適の基板温度に設定したときその温度に合っ
た分解温度の原料を選ぶことができなかった。As described above, when the optimum substrate temperature is set in view of crystal growth, it is impossible to select a raw material having a decomposition temperature suitable for the temperature.

【０００５】本発明の目的は設定基板温度に合わせて原
料を選び、原料の使用効率を上げると同時に薄膜結晶の
質も向上できる方法を提供することである。An object of the present invention is to provide a method capable of selecting a raw material according to a set substrate temperature, improving the use efficiency of the raw material, and at the same time improving the quality of a thin film crystal.

【０００６】[0006]

【課題を解決するための手段】本発明に係る薄膜の気相
成長法は上記問題点に鑑みてなされたものであり、同一
元素供給のための複数の原料を同時に用い、基板温度に
合わせて原料の混合比を変えて実質的な分解温度を制御
することを特徴とする。The vapor phase growth method of a thin film according to the present invention has been made in view of the above problems, and a plurality of raw materials for supplying the same element are used at the same time and are adjusted to the substrate temperature. It is characterized by controlling the substantial decomposition temperature by changing the mixing ratio of the raw materials.

【０００７】「即ち、（１）薄膜成長において同一元素
供給のための原料として分解温度の異なる複数の原料を
用いることを特徴とする薄膜の気相成長法。（２）III
−Ｖ族化合物の気相成長法により形成する薄膜膜質向上
のために、Ｖ族化合物について分解温度が比較的に高い
Ｖ族元素化合物と低いＶ族元素化合物とを混合しその高
い側の温度で分解させることにより分解温度が比較的に
高い分解生成物と分解温度の低い原料から供給されるＶ
族元素の化学種を用いることを特徴とする上記１項に記
載の薄膜の気相成長法。（３）III−Ｖ族化合物の薄膜
成長を行うに際しＶ族元素の原料としてＴＢＰとＭＭＰ
を供給して行うことを特徴とする上記（２）項に記載の
III−Ｖ族化合物の薄膜の気相成長法。（４）III−Ｖ族
化合物の薄膜成長に際しＶ族元素の原料としてＴＢＰと
ＰＨ₃を供給して行うことを特徴とする上記（２）項に
記載のIII−Ｖ族化合物の薄膜の気相成長法。」を含む
ものである。That is, (1) a vapor phase epitaxy method for thin films, characterized in that a plurality of raw materials having different decomposition temperatures are used as raw materials for supplying the same element in the thin film growth. (2) III
In order to improve the quality of the thin film formed by the vapor phase growth method of the group V compound, the group V compound having a relatively high decomposition temperature and the group V compound having a low decomposition temperature are mixed with each other at a temperature on the higher side thereof. V that is supplied from a decomposition product having a relatively high decomposition temperature and a raw material having a low decomposition temperature due to decomposition
2. The vapor phase epitaxy method for a thin film as described in the above item 1, wherein the chemical species of the group element is used. (3) TBP and MMP as raw materials of the group V element when performing thin film growth of the group III-V compound
The above-mentioned item (2) is characterized in that
Vapor phase growth method for thin films of III-V compounds. (4) (2) above, characterized in that by supplying TBP and PH ₃ as a raw material of group V element upon film growth of group III-V compound vapor of a thin film of Group III-V compound according to claim Growth method. Is included.

【０００８】[0008]

【作用】本発明は上記の方法を用いることにより原料の
使用効率を高め、かつ結晶の質の良好な膜を得ることが
できる。According to the present invention, by using the above method, it is possible to enhance the use efficiency of the raw material and obtain a film having good crystal quality.

【０００９】[0009]

【実施例】以下、本発明の実施例について図面を参照し
て詳細に説明する。Embodiments of the present invention will now be described in detail with reference to the drawings.

【００１０】図１に本発明の一実施例のＩｎ_0.5Ｇａ_0.5
Ｐ成長のための有機金属気相成長装置を概略の断面図で
示す。図中、１は原料供給のための配管、２はステンレ
スで水冷式の気相成長装置、３は気相成長が施される基
板、４は基板を載置するサセプタ、５は排気管である。
まず、１からアルシン（ＡｓＨ₃）を水素キャリアとと
もに４０ｓｃｃｍ供給し、ヒーター４によって７００℃
に昇温したＧａＡｓ（００１）基板３のクリーニングを
行う。その後、トリメチルガリウム（（ＣＨ₃）₃Ｇａ：
ＴＭＧ）を０．２ｓｃｃｍ供給してＧａＡｓバッファ層
を０．５μｍ成長する。その上にトリメチルインジウム
（（ＣＨ₃）₃Ｉｎ：ＴＭＩ）とＴＭＧをそれぞれ０．２
４ｓｃｃｍおよび０．２０ｓｃｃｍ、Ｐ原料はターシャ
リブチルフォスフィン（（ＣＨ₃）₃ＣＰＨ₂：ＴＢＰ）
とモノメチルフォスフィン（ＣＨ₃ＰＨ₂：ＭＭＰ）を
１：２の割合で混合し、III族原料の３０倍（Ｖ／III比
＝３０）供給した。成長圧力は１００Ｔｏｒｒ、使用後
の廃ガスは５から排気した。Ｉｎ_0.5Ｇａ_0.5Ｐは５μｍ
成長した。鏡面で、良好な電気的光学的特性が得られ
た。一方、ＴＢＰ単独で用いた時にはＶ／III比＝１５
０以上、ＭＭＰ単独で用いた時にはＶ／III比＝３５０
以上それぞれ用いないと鏡面は得られなかった。FIG. 1 shows In _0.5 Ga _{0.5 according to} one embodiment of the present invention.
FIG. 1 is a schematic sectional view showing an organometallic vapor phase epitaxy apparatus for P growth. In the figure, 1 is a pipe for supplying a raw material, 2 is a stainless steel water-cooled vapor phase growth apparatus, 3 is a substrate on which vapor phase growth is performed, 4 is a susceptor for mounting the substrate, and 5 is an exhaust pipe. .
First, arsine (AsH ₃ ) was supplied from 1 at 40 sccm together with a hydrogen carrier, and was heated to 700 ° C. by the heater 4.
The GaAs (001) substrate 3 whose temperature has been raised to is cleaned. After that, trimethylgallium ((CH ₃ ) ₃ Ga:
TMG) is supplied at 0.2 sccm to grow a GaAs buffer layer at 0.5 μm. On top of that, trimethylindium ((CH ₃ ) ₃ In: TMI) and TMG were each added to 0.2
4 sccm and 0.20 sccm, P source is tert-butyl phosphine ((CH ₃ ) ₃ CPH ₂ : TBP)
And monomethylphosphine (CH ₃ PH ₂ : MMP) were mixed at a ratio of 1: 2, and supplied 30 times as much as the group III raw material (V / III ratio = 30). The growth pressure was 100 Torr, and the waste gas after use was exhausted from 5. In _0.5 Ga _0.5 P is 5 μm
grown. On the mirror surface, good electro-optical characteristics were obtained. On the other hand, when TBP is used alone, V / III ratio = 15
0 or more, V / III ratio = 350 when used alone with MMP
A mirror surface could not be obtained without using each of the above.

【００１１】Ｉｎ_0.5Ｇａ_0.5Ｐの成長はＧａＡｓバッフ
ァ層までの手順は同じで、７５０℃の基板にＴＭＩを
０．２４ｓｃｃｍ、ＴＭＡを０．１１ｓｃｃｍそれぞれ
供給した。Ｐ原料はＴＢＰとフォスフィン（ＰＨ₃）を
１：３の割合で混合し、Ｖ／III比＝４０で供給した。
その結果、５μｍの成長膜は鏡面で、良好な電気的光学
的特性を示した。一方、ＴＢＰ単独で用いた時にはＶ／
III比＝２５０以上、ＰＨ₃単独で用いた時にはＶ／III
比＝４００以上それぞれ用いないと鏡面は得られなかっ
た。In _0.5 Ga _0.5 P, the procedure up to the GaAs buffer layer was the same, and TMI of 0.24 sccm and TMA of 0.11 sccm were supplied to the substrate at 750 ° C. As the P raw material, TBP and phosphine (PH ₃ ) were mixed at a ratio of 1: 3 and supplied at a V / III ratio = 40.
As a result, the grown film having a thickness of 5 μm was a mirror surface and showed good electro-optical characteristics. On the other hand, when using TBP alone, V /
III ratio = 250 or more, V / III when PH ₃ alone is used
A mirror surface could not be obtained unless the ratio was 400 or more.

【００１２】上の結果はThe above result is

【表１】 および[Table 1] and

【表２】 に纏めて示す。これらの表からＶ族原料を単独に用いる
より混合して用いることにより極めて少量のＶ族原料で
良好な膜が得られることが明らかである。すなわち、Ｖ
族原料の使用効率を極めて増大することができる。[Table 2] Shown together. From these tables, it is clear that a good film can be obtained with an extremely small amount of group V raw material by using a mixture of group V raw materials rather than using them individually. That is, V
The use efficiency of the group raw material can be greatly increased.

【００１３】また、基板温度を変えて成長したが膜の特
性からＩｎ_0.5Ｇａ_0.5ＰとＩｎ_0.5Ａｌ_0.5Ｐで最適な温
度はそれぞれ７００℃と７５０℃であった。Although the growth was carried out while changing the substrate temperature, the optimum temperatures for In _0.5 Ga _0.5 P and In _0.5 Al _0.5 P were 700 ° C. and 750 ° C., respectively, due to the characteristics of the film.

【００１４】このように膜の種類にしたがって膜特性を
最良にするための基板温度が存在し、その温度で最も原
料を有効に使うためには原料の性質を適切に選ぶ必要が
ある。この理由を以下に述べる。As described above, there is a substrate temperature for optimizing film characteristics depending on the type of film, and it is necessary to properly select the properties of the raw material in order to use the raw material most effectively at that temperature. The reason for this will be described below.

【００１５】Ｉｎ_0.5Ｇａ_0.5ＰやＩｎ_0.5Ａｌ_0.5Ｐの成
長はＶ族原料よりIII族原料は分解し易く、III族元素は
蒸気圧が低いのでIII族原料の供給で律速されている
が、膜の質はＶ族原料の性質と供給量に依存する。すな
わち、膜の成長反応は非平衡状態でおこなわれるので活
性な化学種が要求される。しかし、出来た膜を劣化させ
ないためには膜表面の解離（Ｉｎ_0.5Ｇａ_0.5Ｐ，Ｉｎ
_0.5Ａｌ_0.5Ｐ→Ｉｎ，Ｇａ，Ａｌ，Ｐ₂，Ｐ₄）をさせな
いようにＰ₂やＰ₄の分圧を増して熱平衡からずらす必要
がある。Ｐを含む活性な化学種は実施例の場合ではＰＨ
_n（ｎ＝０，１，２）である。すなわち、膜中の欠陥や
不純物を少なくするためには一定分圧以上のＰＨ_n（ｎ
＝０，１，２）と同時にＰ₂やＰ₄の存在が必要である。
これらの化学種が必要であることは発明者が初めて見出
だし、本発明はこの原理に基づいている。In the growth of In _0.5 Ga _0.5 P and In _0.5 Al _0.5 P, the group III raw material is more easily decomposed than the group V raw material, and the vapor pressure of the group III element is low. The quality of the membrane depends on the nature and feed rate of the Group V raw material. That is, since the film growth reaction is carried out in a non-equilibrium state, active chemical species are required. However, in order to prevent deterioration of the formed film, dissociation of the film surface (In _0.5 Ga _0.5 P, In
_0.5 Al _0.5 P → In, Ga, Al, P ₂ , P ₄ ) It is necessary to increase the partial pressure of P ₂ and P ₄ so as not to cause thermal equilibrium. The active species including P is PH in the case of the embodiment.
_n (n = 0, 1, 2). That is, in order to reduce defects and impurities in the film, PH _n (n
= 0, 1, 2) and the presence of P ₂ and P ₄ is required at the same time.
The need for these species was first discovered by the inventor and the present invention is based on this principle.

【００１６】ＰＨ₃，ＭＭＰ，ＴＢＰ，の５０％分解す
る温度はそれぞれ８５０℃、６００℃、４５０℃であ
り、これらを混合した場合、分解温度の低い原料はきわ
めて効率良くＰ₂やＰ₄を供給でき、一方分解温度の高い
原料はきわめて効率良くＰＨ_n（ｎ＝０，１，２）を供
給することができる。単独の原料を用いて両機能を持た
せようとすると大量の原料が必要になる。したがって、
複数の原料によって機能を分担させると供給量は著しく
減少させることができる。ただし、Ｐ原料の混合比と総
量は基板温度によって決める必要がある。The temperatures at which 50% of PH ₃ , MMP, and TBP are decomposed are 850 ° C., 600 ° C., and 450 ° C., respectively, and when these are mixed, the raw materials having a low decomposition temperature are very efficient in converting P ₂ and P ₄ . On the other hand, a raw material having a high decomposition temperature can supply PH _n (n = 0, 1, 2) very efficiently. A large amount of raw material is required to provide both functions by using a single raw material. Therefore,
When the functions are shared by a plurality of raw materials, the supply amount can be significantly reduced. However, it is necessary to determine the mixing ratio and the total amount of the P raw material depending on the substrate temperature.

【００１７】本発明を適用できる半導体はIII−Ｖ族化
合物半導体以外、例えばII−VI族化合物半導体や、Ｓｉ
Ｇｅ等のIV−IV族化合物半導体化合物でも可能である。
II−VI族化合物半導体、例えばＺｎＳｅ単結晶を形成す
る際、ジメチル亜鉛、ジメチルセレンと水素化セレンを
使用することができる。Semiconductors to which the present invention can be applied are other than III-V group compound semiconductors, such as II-VI group compound semiconductors and Si.
It is also possible to use a IV-IV group compound semiconductor compound such as Ge.
When forming a II-VI group compound semiconductor, for example, a ZnSe single crystal, dimethyl zinc, dimethyl selenium, and selenium hydride can be used.

【００１８】[0018]

【発明の効果】以上説明したように本発明による成長法
にしたがえば、原料の使用効率をきわめて高くでき、し
かも良好な膜特性を得ることができる。As described above, according to the growth method of the present invention, the use efficiency of the raw material can be extremely increased and good film characteristics can be obtained.

【図面の簡単な説明】[Brief description of drawings]

【図１】有機金属気相成長法に用いる装置の概略を示す
断面図。FIG. 1 is a sectional view showing an outline of an apparatus used for a metal organic chemical vapor deposition method.

【符号の説明】 １ 原料供給用配管 ２ 気相成長装置 ３ 気相成長が施される基板 ４ サセプタ ５ 排気管[Explanation of symbols] 1 raw material supply pipe 2 vapor growth apparatus 3 substrate on which vapor phase growth is performed 4 susceptor 5 exhaust pipe

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 気相成長によって薄膜成長を行うに際
し、同一元素供給のための原料として分解温度の異なる
複数の原料を用いることを特徴とする薄膜の気相成長
法。1. A vapor phase epitaxy method for a thin film, wherein a plurality of raw materials having different decomposition temperatures are used as raw materials for supplying the same element when the thin film is grown by vapor phase epitaxy. 【請求項２】 III−Ｖ族化合物の気相成長法により形
成する薄膜膜質向上のために、Ｖ族化合物について分解
温度が比較的に高いＶ族元素化合物と低いＶ族元素化合
物とを混合しその高い側の温度で分解させることにより
分解温度が比較的に高いＶ族元素化合物から生ずる分解
生成物と分解温度の低い原料から供給されるＶ族元素の
化学種を用いることを特徴とする請求項１に記載の薄膜
の気相成長法。2. A group V compound having a relatively high decomposition temperature and a group V compound having a relatively low decomposition temperature are mixed in order to improve the quality of a thin film formed by a vapor phase growth method of a group III-V compound. Claims characterized in that a decomposition product produced from a group V element compound having a relatively high decomposition temperature by decomposing at a temperature on the higher side and a chemical species of the group V element supplied from a raw material having a lower decomposition temperature are used. Item 2. A vapor phase growth method for a thin film according to item 1. 【請求項３】 III−Ｖ族化合物の薄膜成長を行うに際
しＶ族元素の原料としてＴＢＰとＭＭＰを供給して行う
ことを特徴とする請求項２に記載のIII−Ｖ族化合物の
薄膜の気相成長法。3. The vapor deposition of the thin film of the III-V group compound according to claim 2, wherein TBP and MMP are supplied as raw materials of the V group element when the thin film of the III-V group compound is grown. Phase growth method. 【請求項４】 III−Ｖ族化合物の薄膜成長に際しＶ族
元素の原料としてＴＢＰとＰＨ₃を供給して行うことを
特徴とする請求項２に記載のIII−Ｖ族化合物の薄膜の
気相成長法。4. The vapor phase of the thin film of the group III-V compound according to claim 2, wherein TBP and PH ₃ are supplied as raw materials of the group V element during the growth of the thin film of the group III-V compound. Growth method.