JPS625674A - Semiconductor light emitting diode - Google Patents
Semiconductor light emitting diodeInfo
- Publication number
- JPS625674A JPS625674A JP60145039A JP14503985A JPS625674A JP S625674 A JPS625674 A JP S625674A JP 60145039 A JP60145039 A JP 60145039A JP 14503985 A JP14503985 A JP 14503985A JP S625674 A JPS625674 A JP S625674A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- active layer
- light
- light emitting
- diameter
- 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.)
- Pending
Links
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Abstract
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明は、光通信システムの光源として有効な、半導体
発光ダイオード(以下LEDと呼ぶ)、特に半導体基板
面に垂直な方向に光を取出す面発光型LEDに関する。Detailed Description of the Invention (Industrial Application Field) The present invention relates to a semiconductor light emitting diode (hereinafter referred to as an LED), which is effective as a light source for an optical communication system, and in particular to a semiconductor light emitting diode (hereinafter referred to as an LED) that emits light in a direction perpendicular to a semiconductor substrate surface. Regarding light-emitting LEDs.
(従来技術とその問題点)
光通信システムの光源としてLEDは、今後増々重要と
なる。このようなLEDでは、発光輝度が高く光ファイ
バーへの光入力が大きいことが重要である。それには、
発光領域の発光効率とともに、光ファイバーへの結合効
率が問題°となる。光通信用ファイバーとして一般的な
グレーデッドインデックスファイバーにLEDの光を結
合させる場合結合効率11eはファイバーのコア径Df
、ファイバーの開口数NA、LEDの発光径Daと次式
の関係で表わされる。(Prior art and its problems) LEDs will become increasingly important as light sources for optical communication systems in the future. For such LEDs, it is important that the luminance is high and the light input to the optical fiber is large. For that,
In addition to the luminous efficiency of the light emitting region, the coupling efficiency to the optical fiber becomes an issue. When coupling LED light to a graded index fiber, which is commonly used as an optical communication fiber, the coupling efficiency 11e is determined by the fiber core diameter Df.
, the numerical aperture NA of the fiber, the emission diameter Da of the LED, and the following equation.
ric;Nup2(i)2 (1)即ち、L
EDの発光径Daが小さいほど結合効率が大きい。従っ
て、発光径をできるだけ小さくすることが望ましい。ric;Nup2(i)2 (1), that is, L
The smaller the emission diameter Da of the ED, the higher the coupling efficiency. Therefore, it is desirable to make the emission diameter as small as possible.
従来より発光径を小さくするためにいくつかの電流狭窄
手段が用いられてきた(光通信素子工学。Several current confinement methods have been used to reduce the emission diameter (optical communication device engineering).
工学図書。(1983)P128〜P134)。一般的
な構造は、酸化膜により電流を狭窄したり、表面近傍に
設けた拡散領域によるpn接合で電流を狭窄した構造で
ある。これら素子表面近傍で電流狭窄を行なう構造では
、電流が、活性層に達するまで、及び活性層内で横方向
に拡がるため発光径が電流狭窄径より数pm大きくなる
とともに発光強度の半径方向の分布に著しいだれが生じ
た。そのため発光径を小さくするには、電流狭窄径をそ
れ以上に数pm以上小さくしなければならないという問
題がある。さらに発光径が小さくなる程発光強度分布の
だれの影響が大きくなり結合効率は(1)式の関係から
大きくずれて発光径を小さくしても結合効率は向上しな
いという問題がある。Engineering books. (1983) P128-P134). A typical structure is one in which the current is constricted by an oxide film or by a pn junction formed by a diffusion region provided near the surface. In these structures where current confinement is performed near the element surface, the current spreads laterally until it reaches the active layer and within the active layer, so the emission diameter becomes several pm larger than the current confinement diameter, and the radial distribution of emission intensity changes. A significant sore occurred. Therefore, in order to reduce the emission diameter, there is a problem in that the current confinement diameter must be further reduced by several pm or more. Furthermore, as the emission diameter becomes smaller, the influence of the drop in the emission intensity distribution becomes larger, and the coupling efficiency deviates greatly from the relationship expressed by equation (1), so that there is a problem that the coupling efficiency does not improve even if the emission diameter is made smaller.
又、活性層にプロトン照射による高抵抗領域を設は電流
を狭窄する構造がある。この場合発光強度分布のだれは
小さくなるが、活性層の発光領域の周囲をプロトン照射
による損傷層で囲まれているため、キャリヤが損傷層で
非発光に失なわれ発光部の発光効率が著しく低下すると
いう問題があった。Further, there is a structure in which a high resistance region is provided in the active layer by proton irradiation to constrict the current. In this case, the drop in the emission intensity distribution becomes smaller, but since the light emitting region of the active layer is surrounded by a damaged layer due to proton irradiation, carriers are lost in the damaged layer to non-emissive states, and the luminous efficiency of the light emitting part is significantly reduced. There was a problem with the decline.
(発明の目的)
本発明はこのような従来の欠点を除去し、発光効率を損
なうことなく結合効率を高め光ファイバーへの光入力の
高いLEDを実現するものである。(Object of the Invention) The present invention eliminates such conventional drawbacks, increases coupling efficiency without impairing luminous efficiency, and realizes an LED with high light input to an optical fiber.
(発明の構成)
本発明によれば、活性層を有するダブルヘテロ積層構造
を備えた半導体発光ダイオードにおいて直径30pm以
下の円板状に限定された活性層を有し、この円板状の活
性層全体を発光領域とし、この活性層に接する2つのヘ
テロ積層界面のうち、主光取り出し口に近い方の界面と
、この活性層側面のなす角度が鋭角であることを特徴と
する半導体発光ダイオードである。(Structure of the Invention) According to the present invention, a semiconductor light emitting diode having a double-hetero laminated structure having an active layer has an active layer limited to a disk shape with a diameter of 30 pm or less, and the disk-shaped active layer A semiconductor light-emitting diode characterized in that the entire area is a light-emitting region, and the angle between the side surface of the active layer and the interface closer to the main light extraction port among two hetero-laminated interfaces in contact with the active layer is an acute angle. be.
(発明の作用、原理) 第1図は本発明の作用、原理を示す図である。(Operation, principle of invention) FIG. 1 is a diagram showing the operation and principle of the present invention.
n型半導体基板11上に、n型半導体クラッド層12、
n型半導体活性層13、p型半導体クラッド層14が順
に形成されており、活性層は、直径約30pm以下の円
板状活性層領域13に限定されている。円板状活性層領
域13の直上部のp型クラッド層表面には、p型電極1
5が全面に形成されており、円板状活性層領域13全体
が発光領域となるようにしている。n型半導体基板11
の表面に設けられた光取出し窓16から出力光を取出す
。On the n-type semiconductor substrate 11, an n-type semiconductor cladding layer 12,
An n-type semiconductor active layer 13 and a p-type semiconductor cladding layer 14 are formed in this order, and the active layer is limited to a disk-shaped active layer region 13 having a diameter of about 30 pm or less. A p-type electrode 1 is provided on the surface of the p-type cladding layer directly above the disk-shaped active layer region 13.
5 is formed on the entire surface, so that the entire disk-shaped active layer region 13 becomes a light emitting region. n-type semiconductor substrate 11
Output light is extracted from a light extraction window 16 provided on the surface of the.
本発明では、活性層が円板状に限定されているため、こ
の円板状領域13に限定され電流が注入され、均一に発
光を生じる。その結果半径方向の発光強度分布は非常に
鋭い矩形状となり、従来みられていた分布のだれは、な
くなる。その結果光ファイバーとの結合効率は著しく改
善される。発明者の実験結果によれば、従来発光径が約
30μm以下では、発光径を小さくしても結合効率の増
加は、大きくなく、飽和した。これは、発光径が小さく
なるにつれて、電流波がりによる発光分布のだれの影響
が大きくなり、有効に結合されなくなるためである。本
発明により、結合効率は、著しく改善されることが実験
により明らかとなった。In the present invention, since the active layer is limited to a disk shape, current is injected only to this disk-shaped region 13, and light is emitted uniformly. As a result, the emission intensity distribution in the radial direction becomes a very sharp rectangular shape, and the droop in the distribution that was conventionally seen disappears. As a result, the coupling efficiency with optical fibers is significantly improved. According to the inventor's experimental results, conventionally, when the emission diameter is about 30 μm or less, the increase in coupling efficiency is not large even if the emission diameter is made small, and the coupling efficiency is saturated. This is because as the diameter of the emitted light becomes smaller, the influence of the current wave on the emitted light distribution becomes greater, and the emitted light is no longer effectively coupled. Experiments have revealed that the present invention significantly improves binding efficiency.
特に発光径が約30pm以下でその改善量は約1゜5〜
2倍と顕著で、径が小さくなる程、改善量が大きかった
。Especially when the emission diameter is about 30 pm or less, the improvement is about 1°5~
It was twice as remarkable, and the smaller the diameter, the greater the improvement.
さらに、従来の、例えばプロトン照射型LEDとは異な
り、活性層発光領域の周囲は、欠陥領域で囲まれていな
いため、発光効率の低下を伴なわない。Furthermore, unlike conventional, for example, proton irradiation type LEDs, the active layer light emitting region is not surrounded by defective regions, so that there is no reduction in light emitting efficiency.
さらに、活性層13と、クラッド層12の界面と、活性
層13の側面のなす角度θを、鋭角としたことにより、
一層の高出力化が得られた。これは、前記界面と側面の
なす角が、直角か、それに近いと、活性層内の水平面方
向へ進む光が、側面で反射され再び活性層の水平面方向
に進む割合が高くなるため、水平面方向の光増巾が強く
なる。そのため、本来必要とする活性層に垂直な方向へ
の光強度が低下するという問題が生じる。これに対し、
本発明では、この角度を鋭角としているため、活性層内
の水平面方向へ進む光が、活性層側面で反射しても、再
び活性層内を水平面方向に進む割合は、著しく小さくな
るため、水平面方向の光増巾が小さくなり、活性層に垂
直な方向への光強度を向上させることができる。さらに
、活性層側面で反射した光は、主光取り出し口である基
板11の方向へ進むので、出力光として利用でき、一層
の高出力化が得られる。Furthermore, by setting the angle θ between the interface between the active layer 13 and the cladding layer 12 and the side surface of the active layer 13 to be an acute angle,
Even higher output was obtained. This is because if the angle between the interface and the side surface is a right angle or close to it, the proportion of light that travels in the horizontal direction within the active layer is reflected at the side surface and travels back to the horizontal direction of the active layer. The light amplification width becomes stronger. Therefore, a problem arises in that the originally required light intensity in the direction perpendicular to the active layer is reduced. On the other hand,
In the present invention, since this angle is an acute angle, even if light traveling in the horizontal direction within the active layer is reflected from the side surface of the active layer, the proportion of light traveling in the horizontal direction within the active layer again becomes extremely small. The light amplification in the direction becomes small, and the light intensity in the direction perpendicular to the active layer can be improved. Furthermore, since the light reflected on the side surface of the active layer travels toward the substrate 11, which is the main light extraction port, it can be used as output light, resulting in even higher output.
(実施例) 第2図は、本発明の、実施例を示す図である。(Example) FIG. 2 is a diagram showing an embodiment of the present invention.
n型InP基板11上に、n型InP層12.n型In
GaAsP活性層13.P型InP層14.P型InG
aAsPコンタクト層17を順に、例えば液相エピタキ
シャル法により形成する。続いてn型InGaAsP活
性層13.P型InP層14及びP型InGaAsPコ
ンタクト層17を、活性層13の直径が30μm以下に
なるように、円形メサ状に残し、他をBrメタノール等
の化学エツチングにより除去する。ここで、エツチング
の深さを活性層13とn型InP層12の界面から、P
コンタクト層17の表面までの距離より20〜50%程
度大きい値にすることにより、活性層13の側面と、前
記界面のなす角度を45度前後と鋭角にすることができ
る。メサの周囲に5i02膜18を形成し、P型InG
aAsP :7ンタクト層17表面に、TiPt膜を形
成し、P型電極15とする。On the n-type InP substrate 11, an n-type InP layer 12. n-type In
GaAsP active layer 13. P-type InP layer 14. P-type InG
The aAsP contact layer 17 is sequentially formed by, for example, liquid phase epitaxial method. Subsequently, an n-type InGaAsP active layer 13. The P-type InP layer 14 and the P-type InGaAsP contact layer 17 are left in a circular mesa shape so that the diameter of the active layer 13 is 30 μm or less, and the rest are removed by chemical etching using Br-methanol or the like. Here, the depth of etching is determined from the interface between active layer 13 and n-type InP layer 12 to P
By making the value approximately 20 to 50% larger than the distance to the surface of the contact layer 17, the angle between the side surface of the active layer 13 and the interface can be made acute to about 45 degrees. A 5i02 film 18 is formed around the mesa, and a P-type InG film 18 is formed around the mesa.
aAsP:7 A TiPt film is formed on the surface of the contact layer 17 to form a P-type electrode 15.
n型InP基板11を厚さ約1100pに研磨した後、
円形メサと同心円状に、直径約10011mの光取出し
窓16を除き他にAnGeNi膜を形成し、n型電極1
8を形成する。After polishing the n-type InP substrate 11 to a thickness of about 1100p,
An AnGeNi film is formed concentrically with the circular mesa except for the light extraction window 16 with a diameter of approximately 10011 m, and an n-type electrode 1 is formed.
form 8.
最後にP電極15上に金メッキ層19を形成する。Finally, a gold plating layer 19 is formed on the P electrode 15.
(発明の効果)
本発明によりLEDの出力光の光ファイバーへの結合効
率が著しく改善し、ファイバー人カパワーが、従来に比
べ、2〜3倍以上向上した。(Effects of the Invention) According to the present invention, the coupling efficiency of the output light of the LED to the optical fiber has been significantly improved, and the fiber power has been improved by more than 2 to 3 times compared to the conventional method.
第1図は、本発明の原理を、第2図は、実施例をそれぞ
れ示す図である。
図中13は活性層、12.14はクラッド層をそれぞれ
示す。FIG. 1 is a diagram showing the principle of the present invention, and FIG. 2 is a diagram showing an embodiment. In the figure, 13 indicates an active layer, and 12 and 14 indicate a cladding layer, respectively.
Claims (1)
光ダイオードにおいて、直径30μm以下の円板状に限
定された活性層を有し、この円板状の活性層全体を発光
領域とし、この活性層に接する2つのヘテロ積層界面の
うち、主光取り出し口に近い方の界面と、この活性層側
面とのなす角度が鋭角であることを特徴とする半導体発
光ダイオード。In a semiconductor light-emitting diode with a double-hetero laminated structure having an active layer, the active layer is limited to a disk shape with a diameter of 30 μm or less, and the entire disk-shaped active layer is used as a light emitting region. A semiconductor light-emitting diode characterized in that, of two contacting hetero-laminated interfaces, the angle between the interface closer to the main light extraction port and the side surface of the active layer is an acute angle.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60145039A JPS625674A (en) | 1985-07-01 | 1985-07-01 | Semiconductor light emitting diode |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP60145039A JPS625674A (en) | 1985-07-01 | 1985-07-01 | Semiconductor light emitting diode |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS625674A true JPS625674A (en) | 1987-01-12 |
Family
ID=15375979
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP60145039A Pending JPS625674A (en) | 1985-07-01 | 1985-07-01 | Semiconductor light emitting diode |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS625674A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5349211A (en) * | 1992-03-26 | 1994-09-20 | Nec Corporation | Semiconductor infrared emitting device with oblique side surface with respect to the cleavage |
JP2007227980A (en) * | 2007-06-08 | 2007-09-06 | Nichia Chem Ind Ltd | Nitride semiconductor light emitting element and method of manufacturing light emitting element |
US7511311B2 (en) | 2002-08-01 | 2009-03-31 | Nichia Corporation | Semiconductor light-emitting device, method for manufacturing the same, and light-emitting apparatus including the same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57143880A (en) * | 1981-03-02 | 1982-09-06 | Fujitsu Ltd | Semiconductor light emitting element and its manufacture |
-
1985
- 1985-07-01 JP JP60145039A patent/JPS625674A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57143880A (en) * | 1981-03-02 | 1982-09-06 | Fujitsu Ltd | Semiconductor light emitting element and its manufacture |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5349211A (en) * | 1992-03-26 | 1994-09-20 | Nec Corporation | Semiconductor infrared emitting device with oblique side surface with respect to the cleavage |
US7511311B2 (en) | 2002-08-01 | 2009-03-31 | Nichia Corporation | Semiconductor light-emitting device, method for manufacturing the same, and light-emitting apparatus including the same |
US8035118B2 (en) | 2002-08-01 | 2011-10-11 | Nichia Corporation | Semiconductor light-emitting device, method for manufacturing the same, and light-emitting apparatus including the same |
US8330179B2 (en) | 2002-08-01 | 2012-12-11 | Nichia Corporation | Semiconductor light-emitting device, method for manufacturing the same, and light-emitting apparatus including the same |
US8742438B2 (en) | 2002-08-01 | 2014-06-03 | Nichia Corporation | Semiconductor light-emitting device, method for manufacturing the same, and light-emitting apparatus including the same |
JP2007227980A (en) * | 2007-06-08 | 2007-09-06 | Nichia Chem Ind Ltd | Nitride semiconductor light emitting element and method of manufacturing light emitting element |
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