JP2001102627A - AlGaInP BASED LIGHT EMITTING DIODE AND FABRICATION THEREOF - Google Patents
AlGaInP BASED LIGHT EMITTING DIODE AND FABRICATION THEREOFInfo
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＡｌＧａＩｎＰ系
発光ダイオード及びその製造方法に関する。[0001] 1. Field of the Invention [0002] The present invention relates to an AlGaInP-based light emitting diode and a method of manufacturing the same.
【０００２】[0002]
【従来の技術】最近、ＡｌＧａＩｎＰ系エピタキシャル
ウェハを用いた高輝度の赤色及び黄色の発光ダイオード
の需要が大幅に伸びている。主な用途は、交通用信号、
自動車のブレーキランプ、フォグランプ等である。2. Description of the Related Art Recently, demand for high-brightness red and yellow light-emitting diodes using an AlGaInP-based epitaxial wafer has been greatly increased. The main applications are traffic signals,
They are, for example, brake lights and fog lights of automobiles.
【０００３】図３は従来のＡｌＧａＩｎＰ系発光ダイオ
ードに用いられるエピタキシャルウェハの断面図であ
る。FIG. 3 is a sectional view of an epitaxial wafer used for a conventional AlGaInP-based light emitting diode.
【０００４】同図に示すエピタキシャルウェハは、ｎ型
ＧａＡｓ基板１上に、有機金属気相成長法（ＭＯＶＰＥ
法）によって、ｎ型ＧａＡｓバッファ層２と、Ｓｅ（ま
たはＳｉ）をドープしたｎ型ＡｌＧａＩｎＰクラッド層
３と、アンドープＡｌＧａＩｎＰ活性層４と、Ｚｎをド
ープしたｐ型ＡｌＧａＩｎＰクラッド層５と、Ｚｎをド
ープしたｐ型ＧａＰ電流拡散層（ウィンドウ層ともい
う。）６とを順次積層した構造となっている。An epitaxial wafer shown in FIG. 1 is formed on an n-type GaAs substrate 1 by metal organic chemical vapor deposition (MOVPE).
Method), an n-type GaAs buffer layer 2, an n-type AlGaInP cladding layer 3 doped with Se (or Si), an undoped AlGaInP active layer 4, a p-type AlGaInP cladding layer 5 doped with Zn, and a doped Zn And a p-type GaP current diffusion layer (also referred to as a window layer) 6.
【０００５】[0005]
【発明が解決しようとする課題】ところで、図３に示し
た従来のＡｌＧａＩｎＰ系発光ダイオードについては、
電流拡散層のｐ型ドーパントとして用いられているＺｎ
がヘテロ界面や隣接層に異常拡散するという問題があ
る。これは、 (1) 電流拡散層は電極からの電流をチップ横方向へ広げ
るには、高いｐ型キャリア濃度（約１×１０18ｃｍ-3以
上）が必要となるため、高濃度のＺｎをドーピングして
いる。The conventional AlGaInP-based light emitting diode shown in FIG.
Zn used as a p-type dopant for the current diffusion layer
Is abnormally diffused to a hetero interface or an adjacent layer. This is because (1) The current diffusion layer needs a high p-type carrier concentration (about 1 × 10 18 cm −3 or more) to spread the current from the electrode in the lateral direction of the chip. Doping.
【０００６】(2) 電流拡散層は前述した電流の拡散性を
向上させるため、５μｍ以上の厚膜成長が必要となり成
長時間が長くなる。(2) The current diffusion layer needs to grow a thick film of 5 μm or more in order to improve the above-described current diffusivity, and the growth time becomes long.
【０００７】(3) ＡｌＧａＩｎＰ系発光素子用エピタキ
シャルウェハは、不純物となる酸素濃度を低減させるた
めに一般的に６５０℃以上の高温で成長させる。(3) An AlGaInP-based epitaxial wafer is generally grown at a high temperature of 650 ° C. or higher in order to reduce the concentration of oxygen serving as an impurity.
【０００８】という上記(1) 〜(3) の三つのことが原因
となって、エピタキシャルウェハ中では成長中に受ける
熱をドライビングフォースとした、Ｚｎの拡散が非常に
起こりやすくなる。Due to the above three factors (1) to (3), diffusion of Zn in the epitaxial wafer becomes very likely to occur in the epitaxial wafer as a driving force by the heat received during the growth.
【０００９】また、Ｚｎは高濃度にドープされた電流拡
散層から、発光領域であるＡｌＧａＩｎＰクラッド層や
活性層へと拡散する。このＺｎの拡散が起こると、拡散
したＺｎが非発光再結合中心をつくり、発光ダイオード
の発光出力を劣化させることが知られている。[0009] Zn diffuses from the heavily doped current diffusion layer into the AlGaInP cladding layer or active layer, which is the light emitting region. It is known that when this diffusion of Zn occurs, the diffused Zn forms a non-radiative recombination center and deteriorates the luminous output of the light emitting diode.
【００１０】さらに、Ｚｎによる非発光再結合中心の影
響は、連続通電することによりさらに顕著になり発光ダ
イオードの信頼性を著しく悪化させるという問題があっ
た。Further, the effect of the non-radiative recombination center due to Zn becomes more remarkable by continuous energization, and there is a problem that the reliability of the light emitting diode is remarkably deteriorated.
【００１１】そこで、本発明の目的は、上記課題を解決
し、高い出力が得られるＡｌＧａＩｎＰ系発光ダイオー
ド及びその製造方法を提供することにある。It is an object of the present invention to provide an AlGaInP-based light-emitting diode capable of solving the above-mentioned problems and obtaining a high output, and a method of manufacturing the same.
【００１２】[0012]
【課題を解決するための手段】上記目的を達成するため
に本発明のＡｌＧａＩｎＰ系発光ダイオードは、裏面に
電極を有するｎ型導電性のＧａＡｓウェハからなる基板
上に、ＡｌＧａＩｎＰ系材料からなるｎ型クラッド層
と、ｎ型クラッド層よりバンドギャップエネルギーが小
さいＡｌＧａＩｎＰ系材料からなる活性層と、活性層よ
りバンドギャップエネルギーが大きいｐ型ＡｌＧａＩｎ
Ｐ系材料からなるｐ型クラッド層と、ｐ型電流拡散層と
が順次積層され、ｐ型電流拡散層の表面の一部に電極が
設けられたＡｌＧａＩｎＰ系発光ダイオードにおいて、
ｐ型電流拡散層の上面及び側面のキャリア濃度がｐ型電
流拡散層の内部よりも高いものである。In order to achieve the above object, an AlGaInP-based light emitting diode according to the present invention is provided on an n-type conductive GaAs wafer having an electrode on the back surface on an n-type n-type GaAs wafer. A cladding layer, an active layer made of an AlGaInP-based material having a smaller band gap energy than the n-type cladding layer, and a p-type AlGaIn having a larger band gap energy than the active layer
In an AlGaInP-based light-emitting diode in which a p-type cladding layer made of a P-based material and a p-type current diffusion layer are sequentially laminated and an electrode is provided on a part of the surface of the p-type current diffusion layer,
The carrier concentration on the top and side surfaces of the p-type current diffusion layer is higher than inside the p-type current diffusion layer.
【００１３】上記構成に加え本発明のＡｌＧａＩｎＰ系
発光ダイオードは、ｐ型電流拡散層がＧａＰか、あるい
はＡｌＧａＡｓからなるのが好ましい。[0013] In addition to the above structure, in the AlGaInP-based light emitting diode of the present invention, the p-type current diffusion layer is preferably made of GaP or AlGaAs.
【００１４】上記構成に加え本発明のＡｌＧａＩｎＰ系
発光ダイオードは、ｐ型電流拡散層の上面及び側面の高
キャリア濃度化が、Ｚｎ添加で行われてもよい。In addition to the above structure, in the AlGaInP-based light emitting diode of the present invention, the carrier concentration on the upper surface and the side surface of the p-type current diffusion layer may be increased by adding Zn.
【００１５】上記構成に加え本発明のＡｌＧａＩｎＰ系
発光ダイオードは、ｐ型電流拡散層の上面及び側面のキ
ャリア濃度が１×１０18ｃｍ-3以上１×１０21ｃｍ-3以
下であるのが好ましい。In addition to the above structure, the AlGaInP-based light emitting diode of the present invention preferably has a carrier concentration of 1 × 10 18 cm −3 or more and 1 × 10 21 cm −3 or less on the top and side surfaces of the p-type current diffusion layer. .
【００１６】本発明のＡｌＧａＩｎＰ系発光ダイオード
の製造方法は、裏面に電極を有するｎ型導電性のＧａＡ
ｓウェハからなる基板上に、ＡｌＧａＩｎＰ系材料から
なるｎ型クラッド層と、ｎ型クラッド層よりバンドギャ
ップエネルギーが小さいＡｌＧａＩｎＰ系材料からなる
活性層と、活性層よりバンドギャップエネルギーが大き
いｐ型ＡｌＧａＩｎＰ系材料からなるｐ型クラッド層
と、ｐ型電流拡散層とを順次積層し、ｐ型電流拡散層の
表面の一部に電極を設けるＡｌＧａＩｎＰ系発光ダイオ
ードの製造方法において、ｐ型電流拡散層の上面及び側
面のキャリア濃度をｐ型電流拡散層の内部よりも高くす
るため、ｐ型電流拡散層を積層した後にｐ型電流拡散層
の半ばまで切り込みを入れた状態でＺｎを含むガス中で
熱処理するか、あるいはＺｎを含有するものを塗布して
熱処理した後にチップをフルカットするものである。The method for manufacturing an AlGaInP-based light-emitting diode of the present invention is directed to an n-type conductive GaAs having an electrode on the back surface.
An n-type cladding layer made of an AlGaInP-based material, an active layer made of an AlGaInP-based material having a smaller band gap energy than the n-type cladding layer, and a p-type AlGaInP-based material having a larger band gap energy than the active layer on a substrate made of an s wafer. In a method for manufacturing an AlGaInP-based light-emitting diode in which a p-type cladding layer made of a material and a p-type current diffusion layer are sequentially laminated and an electrode is provided on a part of the surface of the p-type current diffusion layer, an upper surface of the p-type current diffusion layer Then, in order to make the carrier concentration on the side surface higher than the inside of the p-type current diffusion layer, heat treatment is performed in a gas containing Zn with the p-type current diffusion layer being laminated and then cut into the middle of the p-type current diffusion layer. Alternatively, a chip containing Zn is applied and heat-treated, followed by full cutting of the chip.
【００１７】本発明によれば、電流拡散層のドープ量を
減少させ、ＧａＡｓウェハをハーフカットした状態で例
えばＺｎ等のｐ型ドーパントを拡散することにより、電
流拡散層の上面及び側面のみを高キャリア濃度にするこ
とができる。この結果、活性層側へのドーパントの拡散
が生じることなく電流拡散層を低抵抗化でき、薄い電流
拡散層でも十分な電流拡散と高光出力化とを実現するこ
とができる。According to the present invention, the doping amount of the current diffusion layer is reduced, and a p-type dopant such as Zn is diffused while the GaAs wafer is half-cut, so that only the upper surface and the side surfaces of the current diffusion layer are raised. The carrier concentration can be adjusted. As a result, the resistance of the current diffusion layer can be reduced without diffusion of the dopant to the active layer side, and sufficient current diffusion and high light output can be realized even with a thin current diffusion layer.
【００１８】すなわち、本発明は、上部電極をｐ型電極
として用いる標準的なＡｌＧａＩｎＰ系発光ダイオード
であって、電流拡散層の上面及び側面のみを内部に比べ
て高キャリア濃度とし、電流拡散層の内部を低キャリア
濃度とすることにより、効果的な電流拡散を図ると同時
にＺｎ等のｐ型ドーパントの電流拡散層から活性層への
拡散を抑え、高出力化を達成するものである。That is, the present invention relates to a standard AlGaInP-based light emitting diode in which the upper electrode is used as a p-type electrode, wherein only the upper surface and the side surface of the current diffusion layer have a higher carrier concentration than the inside, and the current diffusion layer has By setting the inside to a low carrier concentration, effective current diffusion is achieved, and at the same time, diffusion of a p-type dopant such as Zn from the current diffusion layer to the active layer is suppressed, thereby achieving high output.
【００１９】[0019]
【発明の実施の形態】以下、本発明の実施の形態を添付
図面に基づいて詳述する。Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
【００２０】図１は本発明のＡｌＧａＩｎＰ系発光ダイ
オードに用いられるエピタキシャルウェハの一実施の形
態を示す断面図である。なお、従来例と同様の部材には
共通の符号を用いた。FIG. 1 is a sectional view showing an embodiment of an epitaxial wafer used for an AlGaInP-based light emitting diode of the present invention. Note that common members are used for members similar to those in the conventional example.
【００２１】同図に示すエピタキシャルウェハは、ｎ型
ＧａＡｓ基板１の上に、ＭＯＶＰＥ法によって、ｎ型Ｇ
ａＡｓバッファ層２と、Ｓｅ（またはＳｉ）をドープし
たｎ型ＡｌＧａＩｎＰクラッド層（以下「ｎ型クラッド
層」という。）３と、アンドープＡｌＧａＩｎＰ活性層
（以下「活性層」という。）４と、Ｚｎをドープしたｐ
型ＡｌＧａＩｎＰクラッド層（以下「ｐ型クラッド層」
という。）５と、Ｚｎをドープしたｐ型ＧａＰ電流拡散
層（ウィンドウ層）６とを順次積層した構造を有してお
り、ｐ型電流拡散層６の上面６ａ及び側面６ｂのキャリ
ア濃度をｐ型電流拡散層６の内部６ｃよりも高くしたも
のである。The epitaxial wafer shown in FIG. 1 is formed on an n-type GaAs substrate 1 by MOVPE.
aAs buffer layer 2, n-type AlGaInP clad layer (hereinafter referred to as "n-type clad layer") 3 doped with Se (or Si), undoped AlGaInP active layer (hereinafter referred to as "active layer") 4, and Zn. Doped p
AlGaInP cladding layer (hereinafter referred to as “p-type cladding layer”)
That. ) 5 and a p-type GaP current diffusion layer (window layer) 6 doped with Zn are sequentially laminated, and the carrier concentration of the upper surface 6 a and the side surface 6 b of the p-type current diffusion layer 6 is determined by the p-type current This is higher than the inside 6c of the diffusion layer 6.
【００２２】本ＡｌＧａＩｎＰ系発光ダイオードは、上
部電極をｐ型電極として用いる標準的なＡｌＧａＩｎＰ
系発光ダイオードであって、ｐ型電流拡散層６の上面６
ａ及び側面６ｂのみをｐ型電流拡散層６の内部６ｃに比
べて高キャリア濃度とし、内部６ｃを低キャリア濃度と
することにより、効果的な電流拡散を図ることができる
と共に、Ｚｎ等のｐ型ドーパントがｐ型電流拡散層６か
ら活性層４へ拡散するのを抑え、高出力化を達成するこ
とができる。The present AlGaInP-based light-emitting diode is a standard AlGaInP light-emitting device using an upper electrode as a p-type electrode.
Based light emitting diode, the upper surface 6 of the p-type current diffusion layer 6.
a and the side surface 6b have a higher carrier concentration than the inside 6c of the p-type current diffusion layer 6 and a low carrier concentration in the inside 6c. It is possible to suppress the diffusion of the p-type dopant from the p-type current diffusion layer 6 into the active layer 4 and achieve high output.
【００２３】このようなＡｌＧａＩｎＰ系発光ダイオー
ドは、裏面に電極を有するｎ型導電性のＧａＡｓウェハ
からなる基板１上に、ｎ型ＧａＡｓバッファ層２と、ｎ
型クラッド層３と、活性層４と、ｐ型クラッド層５と、
ｐ型電流拡散層６とを順次積層し、ｐ型電流拡散層６を
積層した後にｐ型電流拡散層６の半ばまで切り込みを入
れた状態でＺｎを含むガス中で熱処理するか、あるいは
Ｚｎを含有するものを塗布して熱処理した後にＧａＡｓ
ウェハをフルカットし、ｐ型電流拡散層６の表面の一部
に電極を形成することにより得られる。Such an AlGaInP-based light emitting diode comprises an n-type GaAs buffer layer 2 and an n-type GaAs buffer layer 2 on a substrate 1 made of an n-type conductive GaAs wafer having electrodes on the back surface.
Type clad layer 3, active layer 4, p-type clad layer 5,
The p-type current diffusion layer 6 is sequentially laminated, and after the p-type current diffusion layer 6 is laminated, a heat treatment is performed in a gas containing Zn in a state in which the p-type current diffusion layer 6 is cut into the middle, or GaAs after coating and heat treatment
It can be obtained by fully cutting the wafer and forming an electrode on a part of the surface of the p-type current diffusion layer 6.
【００２４】[0024]
【実施例】（実施例）図１に示すような構造の発光波長
６２０ｎｍ付近の赤色発光ダイオード用エピタキシャル
ウェハを作製した。エピタキシャル構造や成長方法等
は、ｐ型電流拡散層６のＺｎ濃度以外は基本的に後述す
る比較例と同様であり、成長したエピタキシャルウェハ
のｐ型電流拡散層（厚さ約４μｍ）６の半ばまで切り込
みを入れた状態でＤＥＺ雰囲気中、６５０℃で熱処理
し、ｐ型電流拡散層６の上面６ａ及び側面６ｂを内部６
ｃに比べて高キャリア濃度とした。EXAMPLE An epitaxial wafer for a red light emitting diode having a light emission wavelength of about 620 nm having a structure as shown in FIG. 1 was produced. The epitaxial structure, the growth method, and the like are basically the same as those of the comparative example described later except for the Zn concentration of the p-type current diffusion layer 6, and the middle of the p-type current diffusion layer (thickness: about 4 μm) 6 of the grown epitaxial wafer. The upper surface 6a and the side surface 6b of the p-type current diffusion layer 6 are heat treated at 650 ° C.
The carrier concentration was higher than that of c.
【００２５】図２は成長したエピタキシャル層中の深さ
方向のＺｎの濃度分布をＳＩＭＳで測定した結果を示す
図である。同図において横軸は深さ軸であり、縦軸はＺ
ｎ濃度軸である。FIG. 2 is a view showing the result of measuring the concentration distribution of Zn in the depth direction in the grown epitaxial layer by SIMS. In the figure, the horizontal axis is the depth axis, and the vertical axis is Z
It is an n concentration axis.
【００２６】同図より成長したエピタキシャル層中の、
深さ方向のＺｎ濃度が低いため、従来例で見られたよう
なＺｎの異常な拡散は見られなかった。In the epitaxial layer grown from FIG.
Since the Zn concentration in the depth direction was low, abnormal diffusion of Zn as in the conventional example was not observed.
【００２７】さらに、このエピタキシャルウェハをフル
カットした後で、従来例と同様に発光ダイオードチップ
を作製し、発光特性を調べた結果、発光出力は１．４ｍ
Ｗであり、順方向動作電圧（２０ｍＡ通電時）は１．８
Ｖであった。Further, after the epitaxial wafer was fully cut, a light emitting diode chip was manufactured in the same manner as in the conventional example, and the light emitting characteristics were examined. As a result, the light emitting output was 1.4 m.
W, and the forward operating voltage (at the time of applying 20 mA) is 1.8.
V.
【００２８】（比較例）図３に示した従来構造の発光波
長６２０ｎｍ付近の赤色発光ダイオード用エピタキシャ
ルウェハを作製した。(Comparative Example) An epitaxial wafer for a red light emitting diode having a light emission wavelength of about 620 nm having a conventional structure shown in FIG. 3 was produced.
【００２９】ｎ型ＧａＡｓ基板１上にＭＯＶＰＥ法で、
ｎ型（Ｓｅドープ）ＧａＡｓバッファ層２と、ｎ型（Ｓ
ｅドープ）（Ａｌ0.7 Ｇａ0.3 ）0.5 Ｉｎ0.5 Ｐクラッ
ド層３と、アンドープ（Ａｌ0.15Ｇａ0.85）0.5 Ｐ活性
層４と、ｐ型（Ｚｎドープ）（Ａｌ0.7 Ｇａ0.3 ）0.5
Ｉｎ0.5 ＩｎＰクラッド層５とを順次成長させ、そのｐ
型（Ｚｎドープ）（Ａｌ0.7 Ｇａ0.3 ）0.5 Ｉｎ0.5 Ｉ
ｎＰクラッド層５の上に厚さ１０μｍのｐ型電流拡散層
６をＭＯＶＰＥ法で成長させた。ｐ型ＡｌＧａＩｎＰク
ラッド層５までのＭＯＶＰＥ成長は、成長温度７００
℃、成長圧力５０ｔｏｒｒ、各層２〜５の成長速度は
０．３〜１．０ｎｍ／ｓｅｃ、Ｖ／III 比は２００〜４
００で行った。On the n-type GaAs substrate 1, the MOVPE method is used.
n-type (Se-doped) GaAs buffer layer 2 and n-type (S
e-doped) (Al 0.7 Ga 0.3 ) 0.5 In 0.5 P cladding layer 3, undoped (Al 0.15 Ga 0.85 ) 0.5 P active layer 4, p-type (Zn-doped) (Al 0.7 Ga 0.3 ) 0.5
An In 0.5 InP clad layer 5 is sequentially grown, and its p
Type (Zn-doped) (Al 0.7 Ga 0.3 ) 0.5 In 0.5 I
A 10 μm-thick p-type current diffusion layer 6 was grown on the nP cladding layer 5 by MOVPE. MOVPE growth up to the p-type AlGaInP cladding layer 5 has a growth temperature of 700
° C, a growth pressure of 50 torr, a growth rate of each layer 2 to 5 of 0.3 to 1.0 nm / sec, and a V / III ratio of 200 to 4
00.
【００３０】ｐ型電流拡散層６は、Ｖ／III 比５０、成
長速度１ｎｍ／ｓｅｃで成長させた。ｐ型クラッド層５
のＺｎ濃度は５×１０17ｃｍ-3、ｐ型電流層６のＺｎ濃
度は１×１０18ｃｍ-3である。The p-type current diffusion layer 6 was grown at a V / III ratio of 50 and a growth rate of 1 nm / sec. p-type cladding layer 5
Is 5 × 10 17 cm −3 , and the Zn concentration of the p-type current layer 6 is 1 × 10 18 cm −3 .
【００３１】図４は成長したエピタキシャル層中の深さ
方向のＺｎの濃度分布を２次イオン分析（ＳＩＭＳ）で
測定した結果を示す図であり、横軸が深さ軸であり、縦
軸がＺｎ濃度軸である。FIG. 4 is a graph showing the results of measurement of the Zn concentration distribution in the depth direction in the grown epitaxial layer by secondary ion analysis (SIMS). The horizontal axis is the depth axis, and the vertical axis is the vertical axis. It is a Zn concentration axis.
【００３２】同図より、ｐ型電流拡散層６のＺｎがｎ型
ＡｌＧａＩｎＰクラッド層３、活性層４の発光領域に大
量に拡散していることが分る。また、このエピタキシャ
ルウェハを加工して、発光ダイオードチップを作製し
た。チップの大きさは３００μｍ角で、チップ下面全体
にｎ型電極を形成し、チップ上面に直径約１５０μｍの
円形のｐ型電極を形成した。ｎ型電極は、金ゲルマニウ
ム、ニッケル、金をそれぞれ厚さ６０ｎｍ、１０ｎｍ、
５００ｎｍの順に蒸着させたものである。ｐ型電極は、
金亜鉛、ニッケル、金をそれぞれ厚さ６０ｎｍ、１０ｎ
ｍ、１０００ｎｍの順に蒸着させたものである。このチ
ップを図示しないステム上に載せ、発光ダイオードの発
光特性を調べた結果、発光出力は０．６ｍＷであり、順
方向動作電圧（２０ｍＷ通電時）は１．９Ｖであった。It can be seen from the figure that Zn in the p-type current diffusion layer 6 is diffused in a large amount into the light-emitting regions of the n-type AlGaInP cladding layer 3 and the active layer 4. The epitaxial wafer was processed to produce a light emitting diode chip. The size of the chip was 300 μm square, an n-type electrode was formed on the entire lower surface of the chip, and a circular p-type electrode having a diameter of about 150 μm was formed on the upper surface of the chip. The n-type electrode is made of gold germanium, nickel, and gold, each having a thickness of 60 nm, 10 nm,
These are deposited in the order of 500 nm. The p-type electrode is
Gold, zinc, nickel and gold are each 60 nm thick, 10 n
m and 1000 nm in that order. The chip was mounted on a stem (not shown), and the light emitting characteristics of the light emitting diode were examined. As a result, the light emitting output was 0.6 mW, and the forward operating voltage (when 20 mW was applied) was 1.9 V.
【００３３】ここで、ｐ型電流拡散層６の上面６ａ及び
側面６ｂを高キャリア濃度にする他の方法として、Ｚｎ
を含むものを塗布する方法や、直接イオン注入する等の
方法を用いてもよい。また、ｐ型電流拡散層６の半ばま
でエピタキシャルウェハをハーフカットする工程は、ダ
イシングで行う代わりにエッチングによって行ってもよ
い。Here, as another method for increasing the carrier concentration on the upper surface 6a and the side surface 6b of the p-type current diffusion layer 6, Zn is used.
May be applied, or a method such as direct ion implantation may be used. The step of half-cutting the epitaxial wafer to the middle of the p-type current diffusion layer 6 may be performed by etching instead of dicing.
【００３４】従来、電流を十分に拡散させ、高い発光効
率を達成するためには、ｐ型電流拡散層６はかなりの厚
さが必要であった。例えば、下記の論文にはＧａＰ層を
数十μｍの堆積させて電流拡散を図っていることが記載
されている。Conventionally, the p-type current diffusion layer 6 needs a considerable thickness in order to sufficiently diffuse the current and achieve high luminous efficiency. For example, the following article describes that a GaP layer is deposited with a thickness of several tens of μm to achieve current diffusion.
【００３５】“Ｔｗｏｆｏｌｄ ｅｆｆｉｃｉｅｎｃｙ
ｉｍｐｒｏｖｅｍｅｎｔ ｉｎ ｈｉｇｈ ｐｅｒｆ
ｏｒｍａｎｃｅ ＡｌＧａＩｎＰ ｌｉｇｈｔ−ｅｍｉ
ｔｔｉｎｇ ｄｉｏｄｅｓ ｉｎ ｔｈｅ ５５５−６
２０ ｎｍ ｓｐｅｃｔｒａｌｒｅｇｉｏｎ ｕｓｉｎ
ｇ ａ ｔｈｉｃｋ ＧａＰ”Ａｐｐｌ．Ｐｈｙｓ．Ｌ
ｅｔｔ．６１（９），３１ Ａｕｇｕｓｔ １９９２ｐ
ｐ．１０４５−１０４７ しかし、ＭＯＶＰＥ法でｐ型電流拡散層６を厚く成長さ
せるためには、多大な成長時間と原料とを消費すること
になる。このような消費を避けるために、上述の論文で
述べられているように、ＧａＰ層だけを別の成長速度の
速い成長法で積層するのは二度手間になるという問題が
ある。"Twofold efficiency"
improvement in high perf
ormance AlGaInP light-emi
tinging diodes in the 555-6
20 nm spectral region usin
gathick GaP "Appl.Phys.L
ett. 61 (9), 31 August 1992p
p. 1045-1047 However, in order to grow the p-type current diffusion layer 6 thickly by the MOVPE method, a large amount of growth time and materials are consumed. In order to avoid such consumption, as described in the above-mentioned paper, there is a problem that it is troublesome to stack only the GaP layer by another growth method with a high growth rate.
【００３６】そこで本発明を用いれば、従来より薄い電
流拡散層でも十分な電流拡散効果が得られるため、素子
の製造にかかる時間や費用を格段に減少させることがで
きる。また、電流拡散層内部のＺｎ濃度を低くすること
ができるので、電流拡散層から活性層へのＺｎの拡散を
抑えることができ、結果的に従来に比べて発光出力や信
頼性の高い発光ダイオードを得ることができる。Therefore, according to the present invention, a sufficient current spreading effect can be obtained even with a current spreading layer thinner than the conventional one, so that the time and cost required for manufacturing the device can be significantly reduced. Further, since the Zn concentration in the current diffusion layer can be reduced, the diffusion of Zn from the current diffusion layer to the active layer can be suppressed, and as a result, a light emitting diode having higher light emission output and higher reliability than the conventional one can be obtained. Can be obtained.
【００３７】[0037]
【発明の効果】以上要するに本発明によれば、次のよう
な優れた効果を発揮する。In summary, according to the present invention, the following excellent effects are exhibited.
【００３８】高い出力が得られるＡｌＧａＩｎＰ系発光
ダイオード及びその製造方法の提供を実現することがで
きる。It is possible to provide an AlGaInP-based light emitting diode capable of obtaining a high output and a method of manufacturing the same.
【図１】本発明のＡｌＧａＩｎＰ系発光ダイオードに用
いられるエピタキシャルウェハの一実施の形態を示す断
面図である。FIG. 1 is a sectional view showing an embodiment of an epitaxial wafer used for an AlGaInP-based light emitting diode of the present invention.
【図２】成長したエピタキシャル層中の深さ方向のＺｎ
の濃度分布をＳＩＭＳで測定した結果を示す図である。FIG. 2 shows Zn in the depth direction in a grown epitaxial layer.
FIG. 4 is a diagram showing the result of measuring the concentration distribution of the sample by SIMS.
【図３】従来のＡｌＧａＩｎＰ系発光ダイオードに用い
られるエピタキシャルウェハの断面図である。FIG. 3 is a cross-sectional view of an epitaxial wafer used for a conventional AlGaInP-based light emitting diode.
【図４】成長したエピタキシャル層中の深さ方向のＺｎ
の濃度分布を２次イオン分析で測定した結果を示す図で
ある。FIG. 4 shows Zn in a depth direction in a grown epitaxial layer.
FIG. 4 is a diagram showing the results of measuring the concentration distribution of the sample by secondary ion analysis.
１ ｎ型ＧａＡｓ基板 ２ ｎ型ＧａＡｓバッファ層 ３ Ｓｅドープｎ型ＡｌＧａＩｎＰクラッド層（ｎ型ク
ラッド層） ４ アンドープＡｌＧａＩｎＰ活性層（活性層） ５ ｐ型ＡｌＧａＩｎＰクラッド層（ｐ型クラッド層） ６ ｐ型ＧａＰ電流拡散層（ｐ型電流拡散層）Reference Signs List 1 n-type GaAs substrate 2 n-type GaAs buffer layer 3 Se-doped n-type AlGaInP cladding layer (n-type cladding layer) 4 undoped AlGaInP active layer (active layer) 5 p-type AlGaInP cladding layer (p-type cladding layer) 6 p-type GaP Current spreading layer (p-type current spreading layer)
フロントページの続き (72)発明者 金田 直樹 茨城県土浦市木田余町3550番地 日立電線 株式会社アドバンスリサーチセンタ内 Ｆターム(参考） 5F041 AA04 CA34 CA53 CA57 CA65 CA73 FF01 Continuation of the front page (72) Inventor Naoki Kaneda 3550 Kida Yomachi, Tsuchiura-shi, Ibaraki Hitachi Cable, Ltd. Advanced Research Center F-term (reference) 5F041 AA04 CA34 CA53 CA57 CA65 CA73 FF01
Claims (5)
ｓウェハからなる基板上に、ＡｌＧａＩｎＰ系材料から
なるｎ型クラッド層と、該ｎ型クラッド層よりバンドギ
ャップエネルギーが小さいＡｌＧａＩｎＰ系材料からな
る活性層と、該活性層よりバンドギャップエネルギーが
大きいｐ型ＡｌＧａＩｎＰ系材料からなるｐ型クラッド
層と、ｐ型電流拡散層とが順次積層され、該ｐ型電流拡
散層の表面の一部に電極が設けられたＡｌＧａＩｎＰ系
発光ダイオードにおいて、上記ｐ型電流拡散層の上面及
び側面のキャリア濃度が上記ｐ型電流拡散層の内部より
も高いことを特徴とするＡｌＧａＩｎＰ系発光ダイオー
ド。1. An n-type conductive GaAs having an electrode on a back surface.
An n-type cladding layer made of an AlGaInP-based material, an active layer made of an AlGaInP-based material having a smaller band gap energy than the n-type clad layer, and a p-type having a larger band gap energy than the active layer on a substrate made of an s wafer. In the AlGaInP-based light-emitting diode, in which a p-type cladding layer made of an AlGaInP-based material and a p-type current spreading layer are sequentially laminated and an electrode is provided on a part of the surface of the p-type current spreading layer, An AlGaInP-based light-emitting diode, wherein the carrier concentration of the upper surface and the side surface of the layer is higher than the inside of the p-type current diffusion layer.
はＡｌＧａＡｓからなる請求項１に記載のＡｌＧａＩｎ
Ｐ系発光ダイオード。2. The AlGaIn according to claim 1, wherein the p-type current diffusion layer is made of GaP or AlGaAs.
P-based light emitting diode.
キャリア濃度化が、Ｚｎ添加で行われた請求項１に記載
のＡｌＧａＩｎＰ系発光ダイオード。3. The AlGaInP-based light emitting diode according to claim 1, wherein the carrier concentration on the upper surface and the side surface of the p-type current diffusion layer is increased by adding Zn.
ャリア濃度が１×１０18ｃｍ-3以上１×１０21ｃｍ-3以
下である請求項１に記載のＡｌＧａＩｎＰ系発光ダイオ
ード。4. The AlGaInP-based light emitting diode according to claim 1, wherein the carrier concentration on the upper surface and the side surface of the p-type current diffusion layer is 1 × 10 18 cm −3 or more and 1 × 10 21 cm −3 or less.
ｓウェハからなる基板上に、ＡｌＧａＩｎＰ系材料から
なるｎ型クラッド層と、該ｎ型クラッド層よりバンドギ
ャップエネルギーが小さいＡｌＧａＩｎＰ系材料からな
る活性層と、該活性層よりバンドギャップエネルギーが
大きいｐ型ＡｌＧａＩｎＰ系材料からなるｐ型クラッド
層と、ｐ型電流拡散層とを順次積層し、該ｐ型電流拡散
層の表面の一部に電極を設けるＡｌＧａＩｎＰ系発光ダ
イオードの製造方法において、上記ｐ型電流拡散層の上
面及び側面のキャリア濃度を上記ｐ型電流拡散層の内部
よりも高くするため、上記ｐ型電流拡散層を積層した後
に上記ｐ型電流拡散層の半ばまで切り込みを入れた状態
でＺｎを含むガス中で熱処理するか、あるいはＺｎを含
有するものを塗布して熱処理した後にＧａＡｓウェハを
フルカットすることを特徴とするＡｌＧａＩｎＰ系発光
ダイオードの製造方法。5. An n-type conductive GaAs having an electrode on a back surface.
An n-type cladding layer made of an AlGaInP-based material, an active layer made of an AlGaInP-based material having a smaller band gap energy than the n-type clad layer, and a p-type having a larger band gap energy than the active layer on a substrate made of an s wafer. In the method for manufacturing an AlGaInP-based light-emitting diode, a p-type cladding layer made of an AlGaInP-based material and a p-type current spreading layer are sequentially laminated and an electrode is provided on a part of the surface of the p-type current spreading layer. In order to make the carrier concentration on the upper surface and the side surface of the diffusion layer higher than the inside of the p-type current diffusion layer, Zn is formed in such a state that the p-type current diffusion layer is laminated and then cut into the middle of the p-type current diffusion layer. Heat-treating in a gas containing Zn, or applying Zn-containing material and then heat-treating the GaAs wafer Method of manufacturing an AlGaInP light-emitting diode according to claim.
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| JP27953099A JP3674412B2 (en) | 1999-09-30 | 1999-09-30 | AlGaInP light emitting diode and method for manufacturing the same |
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Cited By (5)
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| CN100377373C (en) * | 2003-05-27 | 2008-03-26 | 夏普株式会社 | Light-emitting diode and its manufacturing method |
| CN100421273C (en) * | 2005-09-26 | 2008-09-24 | 日立电线株式会社 | Epitaxial wafer for led and light emitting diode |
| CN100440553C (en) * | 2005-06-23 | 2008-12-03 | 华南师范大学 | GaN-based LED extension sheet and its preparation method |
| CN104218125A (en) * | 2013-05-31 | 2014-12-17 | 山东浪潮华光光电子股份有限公司 | A method for white LED growth and the white LED prepared by utilizing the growth method |
| CN109742203A (en) * | 2019-01-14 | 2019-05-10 | 江西兆驰半导体有限公司 | A kind of iii-nitride light emitting devices |
-
1999
- 1999-09-30 JP JP27953099A patent/JP3674412B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100377373C (en) * | 2003-05-27 | 2008-03-26 | 夏普株式会社 | Light-emitting diode and its manufacturing method |
| CN100440553C (en) * | 2005-06-23 | 2008-12-03 | 华南师范大学 | GaN-based LED extension sheet and its preparation method |
| CN100421273C (en) * | 2005-09-26 | 2008-09-24 | 日立电线株式会社 | Epitaxial wafer for led and light emitting diode |
| CN104218125A (en) * | 2013-05-31 | 2014-12-17 | 山东浪潮华光光电子股份有限公司 | A method for white LED growth and the white LED prepared by utilizing the growth method |
| CN104218125B (en) * | 2013-05-31 | 2017-11-17 | 山东浪潮华光光电子股份有限公司 | A kind of growing method of white light LEDs and the white light LEDs prepared using the growing method |
| CN109742203A (en) * | 2019-01-14 | 2019-05-10 | 江西兆驰半导体有限公司 | A kind of iii-nitride light emitting devices |
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|---|---|
| JP3674412B2 (en) | 2005-07-20 |
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