JPH1126382A - Manufacture of gallium nitride compound semiconductor thin film - Google Patents
Manufacture of gallium nitride compound semiconductor thin filmInfo
- Publication number
- JPH1126382A JPH1126382A JP17672097A JP17672097A JPH1126382A JP H1126382 A JPH1126382 A JP H1126382A JP 17672097 A JP17672097 A JP 17672097A JP 17672097 A JP17672097 A JP 17672097A JP H1126382 A JPH1126382 A JP H1126382A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- gas
- gallium nitride
- compound semiconductor
- semiconductor thin
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は窒化ガリウム系化合
物半導体薄膜の製造方法に関する。The present invention relates to a method for manufacturing a gallium nitride-based compound semiconductor thin film.
【０００２】[0002]
【従来の技術】最近、窒化ガリウム系化合物半導体を用
いた青色、緑色発光デバイスが注目されている。このよ
うな発光デバイスを作製するために、ｎ型不純物をドー
プしたｎ型半導体薄膜とｐ型不純物をドープしたｐ型半
導体薄膜とを積層し、ｐｎ接合を形成する方法が一般的
に用いられている。2. Description of the Related Art Recently, blue and green light emitting devices using a gallium nitride-based compound semiconductor have attracted attention. In order to manufacture such a light emitting device, a method of laminating an n-type semiconductor thin film doped with an n-type impurity and a p-type semiconductor thin film doped with a p-type impurity to form a pn junction is generally used. I have.
【０００３】そして、このようなｐｎ接合を形成する窒
化ガリウム系化合物半導体薄膜を成長させる方法とし
て、有機金属気相成長法が良く知られている。この方法
は、サファイアやＳｉＣ等からなる基板が設置された反
応管内に、ＩＩＩ族原料ガスとして有機金属化合物ガス
（トリメチルガリウム（以下、「ＴＭＧ」という。）や
トリメチルアルミニウム（以下、「ＴＭＡ」という。）
等）を、Ｖ族原料ガスとしてアンモニアを供給し、基板
温度をおよそ９００℃〜１１００℃の高温で保持して、
基板上に窒化ガリウム系化合物半導体薄膜を成長させ、
必要に応じて他の不純物ガスを同時に供給しながらｎ
型、あるいはｐ型半導体薄膜を成長させる方法である。
ｎ型不純物としてはケイ素（Ｓｉ）が良く知られてい
る。ｐ型不純物としては、亜鉛（Ｚｎ）やマグネシウム
（Ｍｇ）等が良く知られている。有機金属化合物は、こ
れらの有機金属化合物が収容されたシリンダ内に導入さ
れたキャリアガスである微量の水素中に、バブリング等
により蒸発あるいは昇華させる（以下、単に「バブリン
グ」という。）ことによりガス化させ、さらに反応管に
効率よく供給するための水素や窒素などのキャリアガス
によって輸送される。As a method for growing a gallium nitride-based compound semiconductor thin film forming such a pn junction, a metal organic chemical vapor deposition method is well known. In this method, an organic metal compound gas (trimethyl gallium (hereinafter, referred to as “TMG”) or trimethyl aluminum (hereinafter, referred to as “TMA”) is used as a group III source gas in a reaction tube in which a substrate made of sapphire, SiC, or the like is installed. .)
), While supplying ammonia as a group V source gas and maintaining the substrate temperature at a high temperature of about 900 ° C to 1100 ° C,
Growing a gallium nitride based compound semiconductor thin film on a substrate,
While simultaneously supplying other impurity gases as necessary, n
This is a method of growing a type or p-type semiconductor thin film.
Silicon (Si) is well known as an n-type impurity. As the p-type impurity, zinc (Zn), magnesium (Mg), and the like are well known. The organic metal compound is vaporized or sublimated by bubbling or the like (hereinafter, simply referred to as “bubbling”) in a trace amount of hydrogen, which is a carrier gas introduced into a cylinder containing the organic metal compound, (hereinafter simply referred to as “bubbling”). And transported by a carrier gas such as hydrogen or nitrogen for efficient supply to the reaction tube.
【０００４】従来、窒化ガリウム（以下、「ＧａＮ」と
いう。）を成長させるときのキャリアガスとしては、特
開昭６３−１８８９３８号公報や特開平４−２０９５７
７号公報において開示されているように、水素または窒
素が一般に用いられている。また、従来、窒化ガリウム
系化合物半導体薄膜を成長させるための有機金属気相成
長装置においては、上記２件の公報において開示されて
いるように、薄膜成長面を上向き、または斜め上向きに
保持した基板上に窒化ガリウム系化合物半導体薄膜を成
長させている。Conventionally, as a carrier gas for growing gallium nitride (hereinafter referred to as "GaN"), Japanese Patent Application Laid-Open No. 63-188938 and Japanese Patent Application Laid-Open No. 4-20957 have been used.
As disclosed in Japanese Patent Publication No. 7, hydrogen or nitrogen is generally used. Conventionally, in a metalorganic chemical vapor deposition apparatus for growing a gallium nitride-based compound semiconductor thin film, as disclosed in the above two publications, a substrate having a thin film growth surface held upward or obliquely upward. A gallium nitride-based compound semiconductor thin film is grown thereon.
【０００５】一方、本発明者は特願平８−７２７２１号
において、薄膜成長面を下向きに保持した基板上に窒化
ガリウム系化合物半導体等の薄膜を面内均一に成長する
ことができる有機金属気相成長装置を提案した。本有機
金属気相成長装置によれば、９００〜１１００℃の高温
を必要とする窒化ガリウム系化合物半導体を成長させる
場合においても基板表面への原料供給が効率良くなされ
るという優れた効果が得られる。On the other hand, the present inventor has disclosed in Japanese Patent Application No. 8-72721 an organometallic compound capable of uniformly growing a thin film such as a gallium nitride-based compound semiconductor on a substrate having a thin film growth surface held downward. A phase growth device was proposed. According to the present organometallic vapor phase epitaxy apparatus, an excellent effect of efficiently supplying a raw material to a substrate surface can be obtained even when growing a gallium nitride-based compound semiconductor requiring a high temperature of 900 to 1100 ° C. .
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、本発明
者はさらに研究を重ねた結果、上記薄膜成長面を下向き
に保持した基板上に窒化ガリウム系化合物半導体薄膜を
成長させる有機金属気相成長装置において、一般式がＡ
ｌｘＧａ１−ｘＮ（０≦ｘ≦１）で表される窒化ガリウ
ム系化合物半導体薄膜を成長させる際にキャリアガスと
して水素ガスまたは窒素ガスを用いると、表面が平坦で
且つ結晶性の良好な薄膜が得られないという問題がある
ことを見出すに至った。However, as a result of further studies, the present inventor has found that a metal-organic vapor phase epitaxy apparatus for growing a gallium nitride-based compound semiconductor thin film on a substrate having the above-mentioned thin film growth surface held downward. And the general formula is A
When a hydrogen gas or a nitrogen gas is used as a carrier gas when growing a gallium nitride-based compound semiconductor thin film represented by lxGa1-xN (0 ≦ x ≦ 1), a thin film having a flat surface and good crystallinity can be obtained. I found that there was a problem of not being able to do it.
【０００７】そして、このようにして成長させた窒化ガ
リウム系化合物半導体薄膜を用いて光デバイスを作製す
ると、成長した積層構造の界面の平坦性が悪いために十
分なデバイス特性が得られないという問題がある。When an optical device is manufactured using the gallium nitride-based compound semiconductor thin film thus grown, sufficient device characteristics cannot be obtained due to poor flatness of the interface of the grown laminated structure. There is.
【０００８】そこで、本発明は、有機金属気相成長法に
より、薄膜成長面を下向きに保持した基板上に良好な表
面平坦性と優れた結晶性とを有する窒化ガリウム系化合
物半導体薄膜を成長させることのできる窒化ガリウム系
化合物半導体薄膜の製造方法を提供することを目的とす
る。Accordingly, the present invention provides a method for growing a gallium nitride-based compound semiconductor thin film having good surface flatness and excellent crystallinity on a substrate having a thin film growth surface held downward by a metal organic chemical vapor deposition method. It is an object of the present invention to provide a method for producing a gallium nitride-based compound semiconductor thin film that can be used.
【０００９】[0009]
【課題を解決するための手段】この課題を解決するため
に、本発明の窒化ガリウム系化合物半導体薄膜の製造方
法は、有機金属気相成長法により、反応管内において薄
膜成長面を下向きにして保持された基板上に、一般式が
ＡｌｘＧａ１−ｘＮ（０≦ｘ≦１）で表される窒化ガリ
ウム系化合物半導体薄膜を成長させるもので、水素が２
％以上且つ５０％未満の濃度で混合された窒素をベース
とする混合ガスをキャリアガスに用いて原料ガスを反応
管内へ輸送するようにしたものである。In order to solve this problem, a method of manufacturing a gallium nitride-based compound semiconductor thin film according to the present invention comprises a metalorganic vapor phase epitaxy method in which a thin film growth surface is held downward in a reaction tube. A gallium nitride-based compound semiconductor thin film represented by the general formula AlxGa1-xN (0 ≦ x ≦ 1) is grown on the substrate.
The raw material gas is transported into the reaction tube using a mixed gas based on nitrogen mixed at a concentration of not less than 50% and less than 50% as a carrier gas.
【００１０】これにより、薄膜成長面を下向きに保持し
た基板上に良好な表面平坦性と優れた結晶性とを有する
窒化ガリウム系化合物半導体薄膜を成長させることが可
能になる。This makes it possible to grow a gallium nitride-based compound semiconductor thin film having good surface flatness and excellent crystallinity on a substrate whose thin film growth surface is held downward.
【００１１】[0011]
【発明の実施の形態】本発明の請求項１に記載の発明
は、有機金属気相成長法により、反応管内において薄膜
成長面を下向きにして保持された基板上に、一般式がＡ
ｌｘＧａ１−ｘＮ（０≦ｘ≦１）で表される窒化ガリウ
ム系化合物半導体薄膜を成長させる窒化ガリウム系化合
物半導体薄膜の製造方法であって、水素が２％以上且つ
５０％未満の濃度で混合された窒素をベースとする混合
ガスをキャリアガスに用いて原料ガスを反応管内へ輸送
するようにしたものであり、薄膜成長面を下向きに保持
した基板上に良好な表面平坦性と優れた結晶性とを有す
る窒化ガリウム系化合物半導体薄膜を成長させることが
できるという作用を有する。BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention relates to a method in which a general formula is represented by A on a substrate held by a metalorganic chemical vapor deposition method with a thin film growth surface facing down in a reaction tube.
A method for producing a gallium nitride-based compound semiconductor thin film for growing a gallium nitride-based compound semiconductor thin film represented by lxGa1-xN (0 ≦ x ≦ 1), wherein hydrogen is mixed at a concentration of 2% or more and less than 50%. The raw material gas is transported into the reaction tube using a mixed gas based on nitrogen as a carrier gas, and has good surface flatness and excellent crystallinity on a substrate with the thin film growth surface held downward. Gallium nitride based compound semiconductor thin film having the following characteristics:
【００１２】本発明の請求項２に記載の発明は、請求項
１記載の発明において、窒化ガリウム系化合物半導体薄
膜にｎ型不純物がドープされているものであり、良好な
表面平坦性と優れた結晶性とを有するｎ型の窒化ガリウ
ム系化合物半導体薄膜を成長させることができるという
作用を有する。According to a second aspect of the present invention, in the first aspect of the present invention, the gallium nitride-based compound semiconductor thin film is doped with an n-type impurity, and has a good surface flatness and excellent properties. This has the effect that an n-type gallium nitride-based compound semiconductor thin film having crystallinity can be grown.
【００１３】以下、本発明の実施の形態について、図１
〜図３を用いて説明する。 （実施の形態１）図１は本発明の一実施の形態において
用いられる有機金属気相成長装置の主要部を示す概略図
である。Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a schematic diagram showing a main part of a metal organic chemical vapor deposition apparatus used in an embodiment of the present invention.
【００１４】図１に示す有機金属気相成長装置におい
て、一方端にガス導入口１ａが、他方端にガス排出口１
ｂが開口された反応管１内の上部には、基板２の薄膜成
長面を下向きに保持する基板ホルダ３が配設されてい
る。反応管１の外部で且つ基板ホルダ３の近傍にはヒー
タ４が設置されており、基板２および基板ホルダ３はヒ
ータ４によって加熱される。In the organometallic vapor phase epitaxy apparatus shown in FIG. 1, a gas inlet 1a is provided at one end and a gas outlet 1 is provided at the other end.
A substrate holder 3 for holding the thin film growth surface of the substrate 2 downward is provided in the upper part of the reaction tube 1 where b is opened. A heater 4 is provided outside the reaction tube 1 and near the substrate holder 3, and the substrate 2 and the substrate holder 3 are heated by the heater 4.
【００１５】ガス導入口１ａには、反応管１内にキャリ
アガスおよび原料ガスを導入するためのガス配管が接続
されている。ガス配管は、主キャリアガスである窒素ガ
スおよび水素ガスが流れる第１の配管７ａおよび第２の
配管７ｂと、第２の配管７ｂから２つに分岐してＴＭＧ
およびＴＭＡを取り込むための水素ガスである副キャリ
アガスが流れる第３の配管７ｃおよび第４の配管７ｄ
と、アンモニアが流れる第５の配管７ｅと、モノシラン
（ＳｉＨ4）ガスが流れる第６の配管７ｆとからなる。
これらの第１〜第６の配管７ａ〜７ｆ上には、ガス流量
を制御する流量制御器５ａ〜５ｆがそれぞれ設置されて
いる。また、第３の配管７ｃ上にはＴＭＧが収容された
シリンダ８ｃが、第４の配管７ｄ上にはＴＭＡが収容さ
れたシリンダ８ｄがそれぞれ設置されている。そして、
第１〜第６の配管７ａ〜７ｆは反応管１に向かって順次
相互に合流されており、最終的に１本のガス配管となっ
てガス導入口１ａに接続されている。A gas pipe for introducing a carrier gas and a source gas into the reaction tube 1 is connected to the gas inlet 1a. The gas pipe is divided into a first pipe 7a and a second pipe 7b through which a nitrogen gas and a hydrogen gas, which are main carrier gases, flow, and a second pipe 7b.
Pipe 7c and fourth pipe 7d through which a secondary carrier gas, which is a hydrogen gas for taking in TMA and TMA, flows
And a fifth pipe 7e through which ammonia flows, and a sixth pipe 7f through which monosilane (SiH 4 ) gas flows.
On these first to sixth pipes 7a to 7f, flow controllers 5a to 5f for controlling a gas flow rate are provided, respectively. A cylinder 8c containing TMG is provided on the third pipe 7c, and a cylinder 8d containing TMA is provided on the fourth pipe 7d. And
The first to sixth pipes 7a to 7f are sequentially merged with each other toward the reaction pipe 1, and are finally connected to the gas inlet 1a as one gas pipe.
【００１６】このような有機金属気相成長装置では、原
料ガスである有機金属化合物ガスは、流量制御器５ｃ，
５ｄによって流量を制御された水素ガスである副キャリ
アガスをＩＩＩ族原料であるＴＭＧ、ＴＭＡがそれぞれ
収容されたシリンダ８ｃ，８ｄ内に導入してバブリング
させることによって、これらＴＭＧ、ＴＭＡが気化、含
有されて生成される。そして、これら有機金属化合物ガ
スは、流量制御器５ｅによって流量を制御されたアンモ
ニアとともに、流量制御器５ａ，５ｂによって流量を制
御された窒素ガスおよび水素ガスの混合ガスからなる主
キャリアガスによって効率良く反応管１に供給される。
その後、ＩＩＩ族原料である有機金属化合物ガスとV族
原料ガスであるアンモニアとが反応した後、加熱された
基板２上に、一般式がＡｌｘＧａ１−ｘＮ（０≦ｘ≦
１）で表される窒化ガリウム系化合物半導体薄膜が形成
される。なお、原料ガスの残りは排気ガス６としてガス
排出口１ｂから排出される。In such an organometallic vapor phase epitaxy apparatus, an organometallic compound gas as a source gas is supplied to a flow controller 5c,
The subcarrier gas, which is a hydrogen gas whose flow rate is controlled by 5d, is introduced into the cylinders 8c, 8d containing the group III raw materials, TMG and TMA, respectively, and bubbled, so that the TMG and TMA are vaporized and contained. Is generated. These organometallic compound gases are efficiently mixed with ammonia whose flow rate is controlled by the flow rate controller 5e and a main carrier gas composed of a mixed gas of nitrogen gas and hydrogen gas whose flow rates are controlled by the flow rate controllers 5a and 5b. It is supplied to the reaction tube 1.
Then, after the organometallic compound gas as the group III raw material reacts with the ammonia as the group V raw material gas, the general formula AlxGa1-xN (0 ≦ x ≦
A gallium nitride-based compound semiconductor thin film represented by 1) is formed. The remainder of the source gas is exhausted from the gas outlet 1b as the exhaust gas 6.
【００１７】また、ｎ型不純物のドープされた窒化ガリ
ウム系化合物半導体薄膜を成長させる場合には、ｎ型不
純物であるＳｉが含まれたモノシラン（ＳｉＨ4）ガス
を流量制御器５ｆによって所定量流し、ＴＭＧ、ＴＭ
Ａ、アンモニアなどの原料ガスとともに反応管１に供給
する。When a gallium nitride-based compound semiconductor thin film doped with an n-type impurity is grown, a predetermined amount of monosilane (SiH 4 ) gas containing Si as an n-type impurity is flowed by a flow controller 5f. , TMG, TM
A and the raw material gas such as ammonia are supplied to the reaction tube 1.
【００１８】このように、本実施の形態におけるキャリ
アガスは、有機金属化合物のバブリングに用いられる副
キャリアガスと、原料ガスを効率良く反応管に供給する
ための主キャリアガスとからなる。そして、全キャリア
ガス中の水素ガスの濃度を１０％としてＧａＮ薄膜を成
長する場合には、例えば、ＴＭＧのバブリングに用いら
れる副キャリアガスとして水素ガスを１０ｃｃ／分、原
料を効率良く供給するための主キャリアガスとして窒素
ガスを９リットル／分、水素ガスを０．９９リットル／
分で流す。As described above, the carrier gas in the present embodiment is composed of the subcarrier gas used for bubbling the organometallic compound and the main carrier gas for efficiently supplying the raw material gas to the reaction tube. When a GaN thin film is grown with the concentration of hydrogen gas in all carrier gases being 10%, for example, hydrogen gas is supplied at 10 cc / min as a subcarrier gas used for bubbling TMG to efficiently supply a raw material. 9 l / min, hydrogen gas 0.99 l / min as main carrier gas
Pour in minutes.
【００１９】次に、このような有機金属気相成長装置を
用いた窒化ガリウム系化合物半導体薄膜の成膜工程を説
明する。Next, the step of forming a gallium nitride-based compound semiconductor thin film using such a metal organic chemical vapor deposition apparatus will be described.
【００２０】まず、良く洗浄したサファイアからなる基
板２を反応管１内の基板ホルダ３に設置する。そして、
水素ガスを流しながら基板２の温度を１１００℃に１０
分間保ち、表面に付着している有機物等の汚れや水分を
取り除くためのクリーニングを行う。First, a substrate 2 made of sapphire that has been thoroughly cleaned is placed on a substrate holder 3 in a reaction tube 1. And
The temperature of the substrate 2 was raised to 1100 ° C. while flowing hydrogen gas.
Hold for a minute and perform cleaning to remove dirt and moisture such as organic substances attached to the surface.
【００２１】次に、基板温度を６００℃にまで降下さ
せ、この状態で主キャリアガスとして水素ガスを１０リ
ットル／分、ＴＭＡの含有された原料ガスを生成するた
めの副キャリアガスを５ｃｃ／分、アンモニアを５リッ
トル／分で流しながら、ＡｌＮ層を５００オングストロ
ームの膜厚で成長させる。Next, the substrate temperature is lowered to 600 ° C., and in this state, hydrogen gas is used as a main carrier gas at a rate of 10 liters / minute, and a subcarrier gas for generating a source gas containing TMA is supplied at a rate of 5 cc / minute. The AlN layer is grown to a thickness of 500 angstroms while flowing ammonia at 5 liters / minute.
【００２２】次に、ＴＭＡ用の副キャリアガスのみを止
めて基板温度を１０５０℃まで上昇させた後、窒素ガス
と水素ガスとからなる混合ガスである主キャリアガスを
後述の流量で、新たにＩＩＩ族原料であるＴＭＡ用とＴ
ＭＧ用の副キャリアガスを併せて１０ｃｃ／分で流しな
がら、窒化ガリウム系化合物半導体薄膜を２μｍの膜厚
で成長させる。Next, after stopping only the sub-carrier gas for TMA and raising the substrate temperature to 1050 ° C., the main carrier gas, which is a mixed gas of nitrogen gas and hydrogen gas, is newly added at a flow rate described later. Group III raw materials for TMA and T
A gallium nitride-based compound semiconductor thin film is grown to a thickness of 2 μm while flowing a subcarrier gas for MG at 10 cc / min.
【００２３】このようにして窒化ガリウム系化合物半導
体薄膜を成長させた後、ＴＭＡ用とＴＭＧ用の副キャリ
アガスとアンモニアを止めて、窒素ガスと水素ガスをそ
のままの流量で流しながら室温まで冷却した後、基板２
上に上記薄膜の形成されたウェハーを反応管１から取り
出す。After the gallium nitride-based compound semiconductor thin film was grown in this manner, the subcarrier gas for TMA and TMG and ammonia were stopped, and cooled to room temperature while flowing nitrogen gas and hydrogen gas at the same flow rates. Later, substrate 2
The wafer having the thin film formed thereon is taken out of the reaction tube 1.
【００２４】ここで、本発明者は、以上のような窒化ガ
リウム系化合物半導体薄膜の成膜において、全キャリア
ガス中の水素ガスの濃度をそれぞれ２％、２０％、４５
％として成長させた３種類の窒化ガリウム系化合物半導
体薄膜の試料を作製し、これをそれぞれ実験例１，２，
３とした。水素ガスの濃度を２％とした場合には、主キ
ャリアガスとして、窒素ガスを９．９８リットル／分、
水素ガスを０．０１リットル／分、ＩＩＩ族原料用の副
キャリアガスを１０ｃｃ／分で流した。水素ガス濃度を
２０％とした場合には、主キャリアガスとして、窒素ガ
スを８．０リットル／分、水素ガスを１．９９リットル
／分、ＩＩＩ族原料用の副キャリアガスを１０ｃｃ／分
で流した。水素ガス濃度を４５％とした場合には、主キ
ャリアガスとして、窒素ガスを５．５リットル／分、水
素ガスを４．４９リットル／分、ＩＩＩ族原料用の副キ
ャリアガスを１０ｃｃ／分で流した。Here, the inventor of the present invention has set the concentration of hydrogen gas in all carrier gases to 2%, 20%, and 45% in the formation of the gallium nitride-based compound semiconductor thin film as described above.
% Of gallium nitride-based compound semiconductor thin films were grown, and the samples were prepared as Experimental Examples 1, 2, and 2, respectively.
It was set to 3. When the concentration of hydrogen gas is 2%, 9.98 l / min of nitrogen gas is used as the main carrier gas.
Hydrogen gas was flowed at 0.01 liter / min, and subcarrier gas for group III raw material was flowed at 10 cc / min. When the hydrogen gas concentration is 20%, as a main carrier gas, nitrogen gas is 8.0 liter / min, hydrogen gas is 1.99 liter / min, and a subcarrier gas for group III raw material is 10 cc / min. Shed. When the hydrogen gas concentration is set to 45%, the main carrier gas is 5.5 liters / minute of nitrogen gas, 4.49 liters / minute of hydrogen gas, and 10 cc / minute of subcarrier gas for Group III raw material. Shed.
【００２５】また、このような窒化ガリウム系化合物半
導体薄膜を成長させる工程において、主キャリアガスと
して水素ガスを９．９９リットル／分で流す以外は前述
と同様にして、全キャリアガス中の水素濃度を１００％
にして窒化ガリウム系化合物半導体薄膜を成長させた。
このようにして得られた試料を比較例１とした。In the step of growing such a gallium nitride-based compound semiconductor thin film, the hydrogen concentration in all carrier gases is the same as described above except that hydrogen gas is flowed at 9.99 liters / minute as the main carrier gas. 100%
Thus, a gallium nitride-based compound semiconductor thin film was grown.
The sample thus obtained was used as Comparative Example 1.
【００２６】さらに、このような窒化ガリウム系化合物
半導体薄膜を成長させる工程において、主キャリアガス
として窒素ガスを９．９９リットル／分で流す以外は前
述とと同様にして、全キャリアガス中の水素濃度を１％
にして窒化ガリウム系化合物半導体薄膜を成長させた。
このようにして得られた試料を比較例２とした。Further, in the step of growing such a gallium nitride-based compound semiconductor thin film, the hydrogen in the entire carrier gas is the same as described above except that a nitrogen gas is flowed at 9.99 l / min as a main carrier gas. 1% concentration
Thus, a gallium nitride-based compound semiconductor thin film was grown.
The sample thus obtained was designated as Comparative Example 2.
【００２７】そして、実験例１〜３、比較例１，２の試
料における窒化ガリウム系化合物半導体薄膜の評価を行
った。なお、評価方法として、光学顕微鏡による窒化ガ
リウム系化合物半導体薄膜の表面観察、および窒化ガリ
ウム系化合物半導体薄膜の二結晶Ｘ線回折ロッキングカ
ーブの半値幅の測定とした。The gallium nitride-based compound semiconductor thin films of the samples of Experimental Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated. As the evaluation method, the surface of the gallium nitride-based compound semiconductor thin film was observed with an optical microscope, and the half-width of a double crystal X-ray diffraction rocking curve of the gallium nitride-based compound semiconductor thin film was measured.
【００２８】図２は、本発明の実施の形態２における窒
化ガリウム系化合物半導体薄膜成長時の全キャリアガス
中の水素濃度と二結晶Ｘ線ロッキングカーブの半値幅の
関係を示すグラフである。ここで、二結晶Ｘ線ロッキン
グカーブの半値幅は窒化ガリウム系化合物半導体薄膜の
結晶性を示す指標であり、半値幅の値が小さいほど窒化
ガリウム系化合物半導体薄膜の結晶性が良好である。FIG. 2 is a graph showing the relationship between the hydrogen concentration in all carrier gases and the half-width of a two-crystal X-ray rocking curve when growing a gallium nitride-based compound semiconductor thin film according to the second embodiment of the present invention. Here, the half width of the two-crystal X-ray rocking curve is an index indicating the crystallinity of the gallium nitride-based compound semiconductor thin film, and the smaller the value of the half width, the better the crystallinity of the gallium nitride-based compound semiconductor thin film.
【００２９】図２から分かるように、キャリアガス中の
水素濃度を１％あるいは１００％とした比較例１および
比較例２の試料においては、二結晶Ｘ線ロッキングカー
ブの半値幅はそれぞれ約８分、約１６分であり、水素濃
度を２％から４５％とした本実施の形態における実験例
１，２，３の試料の二結晶Ｘ線ロッキングカーブの半値
幅の値がいずれも６分以下であることと比較して、大き
な違いが認められた。As can be seen from FIG. 2, in the samples of Comparative Example 1 and Comparative Example 2 in which the hydrogen concentration in the carrier gas was 1% or 100%, the half width of the double crystal X-ray rocking curve was about 8 minutes. Approximately 16 minutes, and the values of the half widths of the double crystal X-ray rocking curves of the samples of Experimental Examples 1, 2, and 3 in this embodiment in which the hydrogen concentration was 2% to 45% were 6 minutes or less. There was a big difference compared to what was.
【００３０】また、窒化ガリウム系化合物半導体薄膜試
料の表面状態を光学顕微鏡で観察したところ、比較例１
および比較例２の試料において凹凸が顕著であったのに
対し、実験例１，２，３の試料の表面は非常に平坦で、
凹凸がほとんど認められなかった。When the surface condition of the gallium nitride-based compound semiconductor thin film sample was observed with an optical microscope, Comparative Example 1 was obtained.
And the sample of Comparative Example 2 had remarkable unevenness, whereas the surfaces of the samples of Experimental Examples 1, 2, and 3 were very flat.
Almost no irregularities were observed.
【００３１】したがって、窒素をベースとした全キャリ
アガス中における有機金属化合物のバブリングに用いる
水素キャリアガスをも含めた水素濃度を２％以上５０％
未満とすることにより、良好な表面平坦性と優れた結晶
性とを有する窒化ガリウム系化合物半導体薄膜を得るこ
とができる。Therefore, the hydrogen concentration including the hydrogen carrier gas used for the bubbling of the organometallic compound in all the nitrogen-based carrier gases should be 2% to 50%.
By setting it to less than 1, a gallium nitride-based compound semiconductor thin film having good surface flatness and excellent crystallinity can be obtained.
【００３２】（実施の形態２）本発明における他の実施
の形態は、図１に示す有機金属気相成長装置を用いて窒
化ガリウム系化合物半導体を成長させる工程において、
ＩＩＩ族原料用の副キャリアガスとともに、ｎ型不純物
としてＳｉ源である１０ｐｐｍのＳｉＨ4ガスを５ｃｃ
／分で流す以外は前述の実施の形態１と同様にして、ｎ
型不純物をドープした窒化ガリウム系化合物半導体薄膜
を２μｍの膜厚で成長させるものである。(Embodiment 2) Another embodiment of the present invention relates to a process of growing a gallium nitride-based compound semiconductor using the metal organic chemical vapor deposition apparatus shown in FIG.
5 cc of a 10 ppm SiH 4 gas as a Si source as an n-type impurity together with a subcarrier gas for a group III raw material
Except that the flow rate is n / min.
A gallium nitride-based compound semiconductor thin film doped with a type impurity is grown to a thickness of 2 μm.
【００３３】ここで、実施の形態１と同様にして、全キ
ャリアガス中の水素ガスの濃度を２％、２０％、４５％
として成長させた３種類のｎ型不純物をドープした窒化
ガリウム系化合物半導体薄膜の試料を作製し、それぞれ
実験例４，５，６とした。Here, in the same manner as in the first embodiment, the concentration of hydrogen gas in all carrier gases is set to 2%, 20%, 45%
Samples of gallium nitride-based compound semiconductor thin films doped with three types of n-type impurities grown as described above were prepared, and were set as Experimental Examples 4, 5, and 6, respectively.
【００３４】また、このような窒化ガリウム系化合物半
導体薄膜を成長させる工程において、主キャリアガスと
して水素ガスを９．９９リットル／分で流す以外は同様
にして、全キャリアガス中の水素濃度を１００％にして
ｎ型不純物をドープした窒化ガリウム系化合物半導体薄
膜を成長させた。このようにして得られた試料を比較例
３とした。In the step of growing such a gallium nitride-based compound semiconductor thin film, the hydrogen concentration in the entire carrier gas is reduced to 100 in the same manner except that hydrogen gas is flowed at 9.99 liters / minute as the main carrier gas. %, And a gallium nitride-based compound semiconductor thin film doped with an n-type impurity was grown. The sample thus obtained was designated as Comparative Example 3.
【００３５】さらに、このような窒化ガリウム系化合物
半導体薄膜を成長させる工程において、主キャリアガス
として窒素ガスを９．９９リットル／分で流す以外は同
様にして、全キャリアガス中の水素濃度を１％にしてｎ
型不純物をドープした窒化ガリウム系化合物半導体薄膜
を成長させた。このようにして得られた試料を比較例４
とした。Further, in the step of growing such a gallium nitride-based compound semiconductor thin film, the hydrogen concentration in the entire carrier gas is reduced to 1 in the same manner except that nitrogen gas is flowed at 9.99 liter / min as a main carrier gas. % And n
A gallium nitride-based compound semiconductor thin film doped with a p-type impurity was grown. The sample thus obtained was used as a comparative example 4
And
【００３６】そして、実験例４，５，６、比較例３，４
の試料におけるｎ型不純物のドープされた窒化ガリウム
系化合物半導体薄膜の評価を行った。なお、評価方法と
して、実施の形態１の場合と同様に、光学顕微鏡による
窒化ガリウム系化合物半導体薄膜の表面観察、および窒
化ガリウム系化合物半導体薄膜の二結晶Ｘ線回折ロッキ
ングカーブの半値幅の測定とした。Then, Experimental Examples 4, 5, 6 and Comparative Examples 3, 4
The gallium nitride-based compound semiconductor thin film doped with an n-type impurity in the sample No. was evaluated. Note that, as in the case of Embodiment 1, the surface of the gallium nitride-based compound semiconductor thin film was observed with an optical microscope, and the half-width of the double crystal X-ray diffraction rocking curve of the gallium nitride-based compound semiconductor thin film was measured as in the evaluation method. did.
【００３７】図３は、本発明の実施の形態３における、
ｎ型の窒化ガリウム系化合物半導体薄膜成長時の全キャ
リアガス中における水素濃度と二結晶Ｘ線ロッキングカ
ーブの半値幅との関係を示すグラフ。FIG. 3 shows Embodiment 3 of the present invention.
4 is a graph showing the relationship between the hydrogen concentration in all carrier gases and the half-width of a two-crystal X-ray rocking curve during the growth of an n-type gallium nitride-based compound semiconductor thin film.
【００３８】図３に示すように、キャリアガス中の水素
濃度を１％あるいは１００％とした上記比較例３および
比較例４においては、二結晶Ｘ線ロッキングカーブの半
値幅はそれぞれ約９分、約１７分であり、水素濃度を２
％から４５％とした本実施の形態における実験例４，
５，６の試料の二結晶Ｘ線ロッキングカーブの半値幅の
値がいずれも６分以下であることと比較して、大きな違
いが認められた。なお、これらの傾向は、図２に示され
る実験例１，２，３並びに比較例１および比較例２の傾
向とほぼ同様であった。As shown in FIG. 3, in Comparative Examples 3 and 4 in which the hydrogen concentration in the carrier gas was 1% or 100%, the half width of the X-ray rocking curve was about 9 minutes, respectively. It takes about 17 minutes and the hydrogen concentration is 2
Experimental Example 4 in the present embodiment in which
A big difference was recognized as compared with the value of the half width of the double crystal X-ray rocking curve of each of the samples 5 and 6 being 6 minutes or less. These tendencies were almost the same as those of Experimental Examples 1, 2, 3 and Comparative Examples 1 and 2 shown in FIG.
【００３９】また、窒化ガリウム系化合物半導体薄膜試
料の表面状態を光学顕微鏡で観察したところ、比較例３
および比較例４の試料において凹凸が顕著であったのに
対し、実験例４，５，６における試料の表面は非常に平
坦で、凹凸がほとんど認められなかった。これらの傾向
についても、実験例１，２，３並びに比較例１および比
較例２の傾向と同様である。The surface state of the gallium nitride-based compound semiconductor thin film sample was observed with an optical microscope.
While the sample of Comparative Example 4 had remarkable unevenness, the surfaces of the samples of Experimental Examples 4, 5, and 6 were very flat, and almost no unevenness was observed. These tendencies are similar to those of Experimental Examples 1, 2, 3 and Comparative Examples 1 and 2.
【００４０】したがって、ｎ型不純物がドープされた場
合においても、窒素をベースとした全キャリアガス中に
おける有機金属化合物のバブリングに用いる水素キャリ
アガスをも含めた水素濃度を２％以上５０％未満とする
ことにより、良好な表面平坦性と優れた結晶性とを有す
る窒化ガリウム系化合物半導体薄膜を得ることができ
る。Therefore, even when the n-type impurity is doped, the hydrogen concentration including the hydrogen carrier gas used for bubbling the organometallic compound in all the nitrogen-based carrier gas is set to 2% or more and less than 50%. By doing so, a gallium nitride-based compound semiconductor thin film having good surface flatness and excellent crystallinity can be obtained.
【００４１】なお、薄膜成長面を下向きに保持した基板
上に窒化ガリウム系化合物半導体薄膜を成長させる有機
金属気相成長装置において、窒素をベースとするキャリ
アガスに水素を混合させることにより窒化ガリウム系化
合物半導体薄膜の表面平坦性と結晶性が改善される原因
は、以下のようなものであると想定される。In a metalorganic vapor phase epitaxy apparatus for growing a gallium nitride-based compound semiconductor thin film on a substrate whose thin film growth surface is held downward, a gallium nitride-based compound semiconductor thin film is formed by mixing hydrogen with a nitrogen-based carrier gas. The causes of the improvement in the surface flatness and crystallinity of the compound semiconductor thin film are assumed to be as follows.
【００４２】すなわち、水素をキャリアガスとした場合
には、窒化ガリウム系化合物半導体薄膜の成長初期段階
における核形成密度が低いために、窒化ガリウム系化合
物半導体は三次元的に成長し平坦な膜になりにくい傾向
がある。一方、窒素をベースとするキャリアガスを用い
ると、成長初期段階における成長核形成が促進されると
考えられる。したがって、この窒素をベースとするキャ
リアガス中の水素濃度を調節することにより基板表面へ
の原料輸送効率が増大し、二次元的な横方向成長が促進
され平坦な膜が得られるというものである。That is, when hydrogen is used as the carrier gas, the nucleation density in the initial stage of the growth of the gallium nitride-based compound semiconductor thin film is low. It tends to be difficult. On the other hand, it is considered that the use of a nitrogen-based carrier gas promotes the growth nucleation in the initial stage of growth. Therefore, by adjusting the hydrogen concentration in the nitrogen-based carrier gas, the efficiency of transporting the raw material to the substrate surface is increased, two-dimensional lateral growth is promoted, and a flat film is obtained. .
【００４３】[0043]
【発明の効果】以上のように、本発明によれば、水素が
２％以上且つ５０％未満の濃度で混合された窒素をベー
スとする混合ガスをキャリアガスに用いて原料ガスを反
応管内へ輸送することとしているので、薄膜成長面を下
向きに保持した基板上に良好な表面平坦性と優れた結晶
性とを有する窒化ガリウム系化合物半導体薄膜を成長さ
せることができるという有効な効果が得られる。As described above, according to the present invention, a source gas is introduced into a reaction tube by using a nitrogen-based mixed gas in which hydrogen is mixed at a concentration of 2% or more and less than 50% as a carrier gas. Since the transport is performed, an effective effect that a gallium nitride-based compound semiconductor thin film having good surface flatness and excellent crystallinity can be grown on a substrate having the thin film growth surface held downward can be obtained. .
【００４４】また、本発明によれば、このような窒化ガ
リウム系化合物半導体薄膜を用いてヘテロ構造や量子井
戸構造を有する発光ダイオードやレーザダイオード等の
光デバイスを作製すれば、デバイス特性が十分に発揮さ
れた光デバイスを製造できるという有効な効果が得られ
る。According to the present invention, if an optical device such as a light emitting diode or a laser diode having a heterostructure or a quantum well structure is manufactured using such a gallium nitride-based compound semiconductor thin film, the device characteristics can be sufficiently improved. An effective effect that the produced optical device can be manufactured can be obtained.
【図１】本発明の実施の形態１において用いられる有機
金属気相成長装置の主要部を示す概略図FIG. 1 is a schematic diagram showing a main part of a metal organic chemical vapor deposition apparatus used in Embodiment 1 of the present invention.
【図２】本発明の実施の形態２における窒化ガリウム系
化合物半導体薄膜成長時の全キャリアガス中における水
素濃度と二結晶Ｘ線ロッキングカーブの半値幅との関係
を示すグラフFIG. 2 is a graph showing the relationship between the hydrogen concentration in all carrier gases and the half-width of a two-crystal X-ray rocking curve when growing a gallium nitride-based compound semiconductor thin film according to a second embodiment of the present invention.
【図３】本発明の実施の形態３における、ｎ型の窒化ガ
リウム系化合物半導体薄膜成長時の全キャリアガス中に
おける水素濃度と二結晶Ｘ線ロッキングカーブの半値幅
との関係を示すグラフFIG. 3 is a graph showing the relationship between the hydrogen concentration in all carrier gases and the half-width of a two-crystal X-ray rocking curve during growth of an n-type gallium nitride-based compound semiconductor thin film according to a third embodiment of the present invention.
１ 反応管 １ａ ガス導入口 １ｂ ガス排出口 ２ 基板 ３ 基板ホルダ ４ ヒータ ５ａ，５ｂ，５ｃ，５ｄ，５ｅ，５ｆ 流量制御器 ６ 排気ガス ７ａ 第１の配管 ７ｂ 第２の配管 ７ｃ 第３の配管 ７ｄ 第４の配管 ７ｅ 第５の配管 ７ｆ 第６の配管 ８ｃ，８ｄ シリンダ DESCRIPTION OF SYMBOLS 1 Reaction tube 1a Gas inlet 1b Gas outlet 2 Substrate 3 Substrate holder 4 Heater 5a, 5b, 5c, 5d, 5e, 5f Flow controller 6 Exhaust gas 7a First pipe 7b Second pipe 7c Third pipe 7d Fourth pipe 7e Fifth pipe 7f Sixth pipe 8c, 8d Cylinder
Claims (2)
いて薄膜成長面を下向きにして保持された基板上に、一
般式がＡｌｘＧａ１−ｘＮ（０≦ｘ≦１）で表される窒
化ガリウム系化合物半導体薄膜を成長させる窒化ガリウ
ム系化合物半導体薄膜の製造方法であって、 水素が２％以上且つ５０％未満の濃度で混合された窒素
をベースとする混合ガスをキャリアガスに用いて原料ガ
スを前記反応管内へ輸送することを特徴とする窒化ガリ
ウム系化合物半導体薄膜の製造方法。A gallium nitride-based compound represented by the general formula AlxGa1-xN (0≤x≤1) on a substrate held by a metalorganic vapor phase epitaxy method with a thin film growth surface facing down in a reaction tube. A method of manufacturing a gallium nitride-based compound semiconductor thin film for growing a compound semiconductor thin film, comprising using a nitrogen-based mixed gas containing hydrogen at a concentration of 2% or more and less than 50% as a carrier gas, A method for producing a gallium nitride-based compound semiconductor thin film, wherein the thin film is transported into the reaction tube.
ｎ型不純物がドープされていることを特徴とする請求項
１記載の窒化ガリウム系化合物半導体薄膜の製造方法。2. The method for producing a gallium nitride-based compound semiconductor thin film according to claim 1, wherein said gallium nitride-based compound semiconductor thin film is doped with an n-type impurity.
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| JP17672097A JP3424507B2 (en) | 1997-07-02 | 1997-07-02 | Method of manufacturing gallium nitride based compound semiconductor thin film |
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| JP17672097A JP3424507B2 (en) | 1997-07-02 | 1997-07-02 | Method of manufacturing gallium nitride based compound semiconductor thin film |
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| JP3424507B2 JP3424507B2 (en) | 2003-07-07 |
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| JP17672097A Expired - Fee Related JP3424507B2 (en) | 1997-07-02 | 1997-07-02 | Method of manufacturing gallium nitride based compound semiconductor thin film |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008277841A (en) * | 2003-08-28 | 2008-11-13 | Hitachi Cable Ltd | Method for manufacturing for group iii-v nitride based semiconductor substrate |
| JP2013012683A (en) * | 2011-06-30 | 2013-01-17 | Sharp Corp | Nitride semiconductor light-emitting element and manufacturing method of the same |
| CN108400205A (en) * | 2017-02-06 | 2018-08-14 | 日亚化学工业株式会社 | The manufacturing method of nitride semiconductor luminescent element |
-
1997
- 1997-07-02 JP JP17672097A patent/JP3424507B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008277841A (en) * | 2003-08-28 | 2008-11-13 | Hitachi Cable Ltd | Method for manufacturing for group iii-v nitride based semiconductor substrate |
| JP2013012683A (en) * | 2011-06-30 | 2013-01-17 | Sharp Corp | Nitride semiconductor light-emitting element and manufacturing method of the same |
| US9070805B2 (en) | 2011-06-30 | 2015-06-30 | Sharp Kabushiki Kaisha | Nitride semiconductor light-emitting device and method for producing the same |
| US9530932B2 (en) | 2011-06-30 | 2016-12-27 | Sharp Kabushiki Kaisha | Nitride semiconductor light-emitting device and method for producing the same |
| CN108400205A (en) * | 2017-02-06 | 2018-08-14 | 日亚化学工业株式会社 | The manufacturing method of nitride semiconductor luminescent element |
| CN108400205B (en) * | 2017-02-06 | 2023-02-28 | 日亚化学工业株式会社 | Method for manufacturing nitride semiconductor light emitting element |
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| Publication number | Publication date |
|---|---|
| JP3424507B2 (en) | 2003-07-07 |
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