JPH0567075B2

JPH0567075B2 -

Info

Publication number: JPH0567075B2
Application number: JP16315886A
Authority: JP
Inventors: Masaki Kajita; Mitsuharu Yoshida
Original assignee: Stanley Electric Co Ltd
Current assignee: Stanley Electric Co Ltd
Priority date: 1986-07-11
Filing date: 1986-07-11
Publication date: 1993-09-24
Also published as: JPS6318680A

Description

[Detailed description of the invention]

〓産業上の利用分野〓本発明は、発光ダイオード及びその製造方法に
関するものである。特に発光の外部取出し効率を
高めたものに係る。〓従来の技術〓従来のこの種の発光ダイオードの構造には第３
図、第４図に示すようなものがあり、第３図に示
すものの場合にはGaAs（ガリウム・珪素）基板
２０（ウエハ）上にGaAlAs（ガリウム・アルミ
ニウム・珪素）によるP2層２１、P1層２２、P0
層２３、Ｎ層２４を成長させ、前記P0層２３を
活性層とするダブルヘテロ構造として発光ダイオ
ードを得るものであり、このときにGaAs基板２
０は光を吸収し発光の外部取出し効率が低下する
ので、第４図に示すように前記GaAs基板２０を
発光ダイオード形成後に取去つたものもある。〓発明が解決しようとする問題点〓しかしながら、前記した従来のものは、第３図
のものは前記GaAs基板にその発光を吸収されて
暗い発光ダイオードしか得られないという問題点
を生ずるものであり、その問題点の解決を計つた
第４図のものでは明かるさの点の問題点は解決さ
れているが、基板を取去つたことでチツプが薄く
機械的強度に劣るものとなり、その後の組立工程
に支障を来たす新たな問題点を生ずるものであつ
た。〓問題点を解決するための手段〓本発明は前記した従来のものに生ずる問題点を
解決するための具体的手段として、GaP基板上に
複層のGaAsP層を配して成るウエハ上に、Ｐ層、
活性層、Ｎ層を有するGaAlAs層を成長し、該
GaAlAs層のGa_(1-X)とAl_(X)との関係（但し０≦Ｘ
≦１）を調整することで、前記活性層から前記
GaP基板側は光学的屈折率が前記活性層より段階
的に大きくなるように複層に成長させ、該
GaAlAsによりダブルヘテロ構造あるいはシング
ルヘテロ構造の発光部を形成することを特徴とす
る発光ダイオードの製造法を提供することで、前
記従来の問題点を解決するものである。〓実施例〓つぎに、本発明を図に示す一実施例に基づいて
詳細に説明する。第１図に符号１０で示すものは本発明の発光ダ
イオードに採用されるGaP基板１１上に二層の
GaAsP層を配して成るウエハであり、前記GaP
基板１１上に直接に成長されたGaAsP層は勾配
層１２であり、コンスタント層１３として更に上
層に配されたGaAsP層と前記GaP基板１１との
中間にあつて、前記の両層１１，１３間に生ずる
格子定数の不整合を緩和する。本発明においては、以上に説明したウエハ１０
上にGaAlAs層を成長させて発光ダイオードを形
成するものであり、先ず第２図に示すように、第
一層として前記ウエハ１０のGaAsP層であるコ
ンスタント層１３と発光ダイオードを構成する
GaAlAs層と格子定数の不整合を緩和するために
Ga（ガリウム）とAl（アルミニユウム）とを
Ga_(1-x)とAl_(x)との関係（但し０≦ｘ≦１）におい
て組成を変化させてP2層１を成長させて、更に
同様に前記の組成を変化させてP1層２、活性層
３、Ｎ層４と順次成長させて発光ダイオードを構
成するものであるが、このとき、前記ｘの値が、 P2層１＞P1層２＞活性層３となるように調整する。この様にしたことで、前記P1層２と活性層３
とＮ層４とでダブルヘテロ構造の発光ダイオード
が得られるものとなる。このときに前記GaとAl
との関係であるｘをP2層１＞P2層２＞活性層３
の様に調整したことは前記の各層の屈折率の関係
も、P2層１＞P1層２＞活性層３となり、しかも、
使用したウエハ１０における屈折率の関係もGaP
基板１１＞勾配層１２＞コンスタント層１３であ
り、更にコンスタト層１３＞P2層１であるので、
前記活性層３で発光し、前記GaP基板１１側に向
かう光は、第２図に矢印Ｒ１〜Ｒ４で示すように
効率良く結晶内を通過して外部に放射され、従来
例のもののようにウエハに吸収されることがな
い。また、Ｎ層側に発光する光は従来のものと同
様に、全ての光は外部に放散されるものであり、
ここでの詳細な説明は省略する。尚、この実施例では、前記ウエハ１０側がＰ型
半導体の例で説明を行つたが、実施に当たつては
これに制限されるものでなく、前記ウエハ１０が
Ｎ型の半導体であつても同様に実施できるもので
あるというまでもない。〓発明の効果〓以上の説明したように、本発明によりGaP基板
上に複層のGaAsP層を配して成るウエハ上に、
GaAlAs層のGa_(1-x)とAl_(x)との関係（但し０≦ｘ
≦１）を調整することで、前記GaP基板側が光学
的屈折率が段階的に大きくなるように複層に成長
させ、該複層のGaAlAs層によりダブルヘテロ構
造あるいはシングルヘテロ構造の発光部を形成し
て発光ダイオードを製造するようにしたことで、
透明なGaP基板が使用可能となり、従来例のもの
のように基板に発光の一部を吸収されて光の外部
取出し効率を減ずることもなく、また、前記基板
を取去り、前記外部取出し効率の向上を計る工程
も不要とし、強度も十分なものとして後の工程で
の取扱いも容易なものとして生産工程の効率向上
に大きな効果を奏するものである。〓Field of Industrial Application〓 The present invention relates to a light emitting diode and a method for manufacturing the same. In particular, the present invention relates to one that increases the efficiency of emitting light to the outside. 〓Conventional technology〓 The conventional structure of this type of light emitting diode has a third
In the case of the one shown in Figure 3, there is a P2 layer 21 and a P1 layer made of GaAlAs (gallium aluminum silicon) on a GaAs (gallium silicon) substrate 20 (wafer). 22, P0
The layer 23 and the N layer 24 are grown to obtain a light emitting diode as a double heterostructure with the P0 layer 23 as the active layer.
Since the GaAs substrate 20 absorbs light and reduces the efficiency of emitting light to the outside, as shown in FIG. 4, the GaAs substrate 20 is removed after forming the light emitting diode. 〓Problems to be Solved by the Invention〓 However, the conventional device described above, as shown in Fig. 3, has the problem that the GaAs substrate absorbs the emitted light, resulting in only a dark light emitting diode. The problem of brightness was solved in the one shown in Figure 4, which was designed to solve this problem, but by removing the substrate, the chip became thinner and had poorer mechanical strength, which made it difficult to use after that. This created a new problem that hindered the assembly process. 〓Means for solving the problems〓 The present invention is a specific means for solving the problems that occur in the conventional ones as described above. P layer,
Grow a GaAlAs layer with an active layer and an N layer, and
The relationship between Ga _(1-X) and Al _(X) in the GaAlAs layer (0≦X
By adjusting ≦1), from the active layer to the
The GaP substrate side is grown in multiple layers so that its optical refractive index becomes stepwise larger than that of the active layer.
The above-mentioned conventional problems are solved by providing a method for manufacturing a light emitting diode characterized in that a light emitting portion of a double heterostructure or a single heterostructure is formed of GaAlAs. Embodiment Next, the present invention will be described in detail based on an embodiment shown in the drawings. What is indicated by the reference numeral 10 in FIG.
This is a wafer formed by disposing a GaAsP layer, and the GaAsP layer is
The GaAsP layer grown directly on the substrate 11 is a gradient layer 12, which is located between the GaAsP layer disposed further above as a constant layer 13 and the GaP substrate 11, and between the two layers 11 and 13. Alleviates the lattice constant mismatch that occurs in In the present invention, the wafer 10 described above is
A light emitting diode is formed by growing a GaAlAs layer thereon, and as shown in FIG.
To alleviate the mismatch between GaAlAs layer and lattice constant
Ga (gallium) and Al (aluminum)
P2 layer 1 is grown by changing the composition in the relationship between Ga _(1-x) and Al _(x) (0≦x≦1), and P1 layer 2 is grown by changing the composition in the same manner. The active layer 3 and the N layer 4 are grown sequentially to form a light emitting diode. At this time, the value of x is adjusted so that P2 layer 1>P1 layer 2>active layer 3. By doing this, the P1 layer 2 and the active layer 3
A light emitting diode with a double hetero structure can be obtained by combining this and the N layer 4. At this time, the Ga and Al
The relationship x is P2 layer 1 > P2 layer 2 > active layer 3
By adjusting the above, the relationship of the refractive index of each layer becomes P2 layer 1>P1 layer 2>active layer 3, and furthermore,
The relationship between the refractive index of the wafer 10 used is also GaP.
Since substrate 11>gradient layer 12>constant layer 13, and furthermore, constant layer 13>P2 layer 1,
The light emitted from the active layer 3 and directed towards the GaP substrate 11 side efficiently passes through the crystal and is radiated to the outside as shown by arrows R1 to R4 in FIG. will not be absorbed into the In addition, all the light emitted from the N layer side is dissipated to the outside, as in the conventional case.
Detailed explanation here will be omitted. In this embodiment, the wafer 10 side is a P-type semiconductor, but the implementation is not limited to this, and even if the wafer 10 is an N-type semiconductor. Needless to say, it can be implemented in the same way. 〓Effects of the Invention〓 As explained above, according to the present invention, on a wafer formed by disposing multiple GaAsP layers on a GaP substrate,
The relationship between Ga _(1-x) and Al _(x) in the GaAlAs layer (0≦x
By adjusting ≦1), the GaP substrate side is grown as a multilayer so that the optical refractive index increases stepwise, and the multilayer GaAlAs layer forms a double heterostructure or single heterostructure light emitting part. By starting to manufacture light emitting diodes,
A transparent GaP substrate can now be used, and unlike conventional substrates, part of the emitted light is not absorbed by the substrate and the efficiency of light extraction to the outside is reduced, and the efficiency of light extraction to the outside can be improved by removing the substrate. It eliminates the need for a measuring process, has sufficient strength, and is easy to handle in subsequent processes, which has a great effect on improving the efficiency of the production process.

[Brief explanation of drawings]

第１図は本発明で用いるウエハを示す断面図、
第２図は本発明による発光ダイオードを示す断面
図、第３図及び第４図は従来例を示す断面図であ
る。１……P2層、２……P1層、３……活性層、４
……Ｎ層、１０……ウエハ、１１……GaP基板、
１２……勾配層、２３……コンスタント層。 FIG. 1 is a cross-sectional view showing a wafer used in the present invention;
FIG. 2 is a sectional view showing a light emitting diode according to the present invention, and FIGS. 3 and 4 are sectional views showing a conventional example. 1...P2 layer, 2...P1 layer, 3...active layer, 4
...N layer, 10...wafer, 11...GaP substrate,
12... Gradient layer, 23... Constant layer.

Claims

[Claims] 1. A wafer consisting of multiple GaAsP layers arranged on a GaP substrate has a P layer, an active layer, and an N layer.
A GaAlAs layer is grown, and the Ga _(1-X) of the GaAlAs layer is
By adjusting the relationship with Al _(X) (0≦X≦1), a multilayer structure of GaAlAs is formed so that the optical refractive index from the active layer to the GaP substrate side becomes stepwise larger than that of the active layer. 1. A method for manufacturing a light emitting diode, which comprises growing a layer to form a double heterostructure or single heterostructure light emitting section using the GaAlAs. 2 A wafer consisting of multiple GaAsP layers arranged on a GaP substrate has a P layer, an active layer, and an N layer.
The side from the active layer to the GaP substrate has a multilayer GaAlAs layer whose optical refractive index is stepwise larger than that of the active layer, and the GaAlAs layer has a double heterostructure or a single heterostructure. A light emitting diode characterized by being a light emitting part.