JPH03114277A - Semiconductor light-emitting element - Google Patents

Semiconductor light-emitting element

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Publication number
JPH03114277A
JPH03114277A JP1250450A JP25045089A JPH03114277A JP H03114277 A JPH03114277 A JP H03114277A JP 1250450 A JP1250450 A JP 1250450A JP 25045089 A JP25045089 A JP 25045089A JP H03114277 A JPH03114277 A JP H03114277A
Authority
JP
Japan
Prior art keywords
layer
light
substrate
light emitting
semiconductor
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
Application number
JP1250450A
Other languages
Japanese (ja)
Other versions
JP3141888B2 (en
Inventor
Toshihide Izumitani
敏英 泉谷
Yasuo Oba
康夫 大場
Gokou Hatano
波多野 吾紅
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toshiba Corp filed Critical Toshiba Corp
Priority to JP25045089A priority Critical patent/JP3141888B2/en
Priority to US07/588,858 priority patent/US5103271A/en
Priority to DE69025842T priority patent/DE69025842T2/en
Priority to EP90310680A priority patent/EP0420691B1/en
Publication of JPH03114277A publication Critical patent/JPH03114277A/en
Priority to US07/819,976 priority patent/US5235194A/en
Priority to US08/058,221 priority patent/US5317167A/en
Application granted granted Critical
Publication of JP3141888B2 publication Critical patent/JP3141888B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To reduce the absorption of radiant light in a substrate even in case the title element is luminesced at a green region and to contrive the improvement of the luminance of the element by a method wherein a light-reflection layer consisting of alternately laminated films, whose compositions are different from one another, is formed between a luminous layer and the substrate. CONSTITUTION:In a semiconductor light-emitting element, which has a luminous layer consisting of P-N junction on a semiconductor substrate and in which a semiconductor forming the luminous layer is formed of InxGayAl1-x-yP (0<=x<=1, 0<=y<=1), a light-reflection layer consisting of alternately laminated films, whose compositions are different from one another, is formed between the luminous layer and the substrate. For example, a P-type GaAs buffer layer 12 and a P-type InGaP intermediate band gap layer 13 are grown and formed on a P-type GaAs substrate 11 and moreover, a light-reflection layer 14 consisting of a multiple structure of a P-type InAlP and a P-type InGaAlP is grown and formed on this layer 13. The layer 14 is formed at a laminate period in a degree of 1/2 of luminous wavelength for making high a reflectivity.

Description

【発明の詳細な説明】 [発明の目的コ (産業上の利用分野) 本発明は、■−V族化合物半導体を用いた半導体発光素
子に係わり、特に短波長(緑色)領域で発光する高輝度
の半導体発光素子に関する。
[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention relates to a semiconductor light emitting device using a ■-V group compound semiconductor, and particularly a high luminance device that emits light in a short wavelength (green) region. The present invention relates to a semiconductor light emitting device.

(従来の技術) 近年、情報処理技術の長足の進歩により、光通信用、光
媒体記録用及び表示用の光源として半導体発光素子の需
要が急増している。中でも情報の高密度化に伴い、現在
主流の赤色より短波長の緑色に光る高輝度の発光ダイオ
ード(以下LEDと略記する)の開発が益々強く望まれ
ている。
(Prior Art) In recent years, with the rapid progress of information processing technology, the demand for semiconductor light emitting devices as light sources for optical communication, optical media recording, and display has rapidly increased. In particular, with the increasing density of information, there is an increasing desire to develop high-intensity light emitting diodes (hereinafter abbreviated as LEDs) that emit green light with a shorter wavelength than the currently mainstream red color.

これまでGaP、GaAsという化合物半導体や、Al
GaAs、Ga1nAsP等の混晶半導体で黄色から近
赤外領域での発光が利用されている。しかし、比較的短
波長発光のGaPでは発光効率が低く、発光効率の良い
混晶半導体は本来赤外用であり、700nm程度の波長
が限界と考えられている。そこで、バンドギャップが1
.9〜2.4eV程度と発光波長の下限値がある程度低
く、直接遷移型のバンド構造で発光効率の高い材料とし
て、GaAs基板に格子整合したInGaAIPが最も
適していると考えられる。このような混晶半導体は、ペ
テロ接合を形成し発光効率を改善する場合にも都合がよ
い。
Until now, compound semiconductors such as GaP and GaAs, and Al
Mixed crystal semiconductors such as GaAs and Ga1nAsP are used to emit light in the yellow to near-infrared region. However, GaP, which emits light at a relatively short wavelength, has low luminous efficiency, and mixed crystal semiconductors with high luminous efficiency are originally intended for infrared light, and a wavelength of about 700 nm is considered to be the limit. Therefore, the band gap is 1
.. InGaAIP, which is lattice-matched to a GaAs substrate, is considered to be most suitable as a material with a relatively low lower limit value of the emission wavelength of about 9 to 2.4 eV, a direct transition type band structure, and high emission efficiency. Such a mixed crystal semiconductor is also convenient for forming a Peter junction and improving luminous efficiency.

しかしながら、この種の半導体発光素子にあっては次の
ような問題があった。即ち、緑色等の短波長で発光する
LEDを作成する場合は、発光波長に対して基板のバン
ドギャップが狭いため、発光層から基板側に向かう放射
光の多くの部分は基板で吸収されてしまう。このため、
光取出し電極側から放射される光は発光層から直接光取
出し電極側に向かう光成分のみとなり、十分な輝度が取
れないという問題が生じる。なお、この混晶は抵抗が比
較的高く、しかも厚膜の成長が困難であるという理由か
ら、これまでGaAlAs系のLEDで採用してきた基
板除去の方法が利用できない。
However, this type of semiconductor light emitting device has the following problems. In other words, when creating an LED that emits light at a short wavelength such as green, the band gap of the substrate is narrow relative to the emission wavelength, so a large portion of the emitted light directed from the light emitting layer to the substrate side is absorbed by the substrate. . For this reason,
The light emitted from the light extraction electrode side is only a light component that goes directly from the light emitting layer to the light extraction electrode side, resulting in a problem that sufficient brightness cannot be obtained. Note that this mixed crystal has a relatively high resistance and it is difficult to grow a thick film, so the substrate removal method that has been used for GaAlAs-based LEDs cannot be used.

一方、発光層と光取出し側電極との間にはコンタクト層
が存在するが、このコンタクト層における放射光の吸収
も輝度を低下させる要因となる。コンタクト層として放
射光に対して透明な化合物半導体材料(例えばI nG
aA I P)を用いれば吸収は少なくなるが、このよ
うな半導体材料を発光層の上に厚く成長形成することは
容易ではない。
On the other hand, there is a contact layer between the light emitting layer and the light extraction side electrode, and the absorption of emitted light in this contact layer also becomes a factor in reducing the brightness. A compound semiconductor material transparent to synchrotron radiation (e.g. InG) is used as the contact layer.
Although absorption can be reduced by using aA I P), it is not easy to grow such a semiconductor material thickly on the light emitting layer.

(発明が解決しようとする課8) このように従来、緑色等の短波長で発光する半導体発光
素子においては、基板における放射光の吸収が大きく、
これが輝度を低下させる要因となっていた。
(Issue 8 to be solved by the invention) As described above, in conventional semiconductor light emitting devices that emit light at short wavelengths such as green, the absorption of emitted light in the substrate is large;
This was a factor in reducing brightness.

本発明は、上記事情を考慮してなされたもので、その目
的とするところは、InGaAIP等のバンドギャップ
の大きい化合物半導体を発光層として用い、緑色領域で
発光させる場合にも、基板における放射光の吸収を低減
することができ、輝度の向上をはかり得る半導体発光素
子を提供することにある。
The present invention has been made in consideration of the above circumstances, and its purpose is to use a compound semiconductor with a large band gap such as InGaAIP as a light emitting layer, and to emit light in the substrate even when emitting light in the green region. An object of the present invention is to provide a semiconductor light emitting device that can reduce absorption of light and improve brightness.

[発明の目的] (課題を解決するための手段) 本発明の骨子は、基板における放射光の吸収を防止する
ために、基板と発光層とめ間に放射光を反射させる光反
射層を形成し、光取出しの低効率という問題を光反射層
で基板側への光を取出し側に反射させる方法で解決する
ことにある。
[Objective of the Invention] (Means for Solving the Problems) The gist of the present invention is to form a light reflecting layer between the substrate and the light emitting layer to reflect the radiated light in order to prevent the absorption of the radiated light in the substrate. The object of the present invention is to solve the problem of low light extraction efficiency by using a light reflecting layer to reflect light directed toward the substrate toward the extraction side.

即ち本発明は、GaAs等のバンドギャップの小さい化
合物半導体基板上にpn接合からなる発光層を有し、該
発光層を形成する半導体をI n)(G ay A l
 1−x−y P (0≦x≦1,0≦y≦1)とした
半導体発光素子において、前記発光層と基板との間に、
異なる組成の交互積層膜からなる光反射層を形成するよ
うにしたものである。
That is, the present invention has a light emitting layer made of a pn junction on a compound semiconductor substrate with a small band gap such as GaAs, and the semiconductor forming the light emitting layer is
In the semiconductor light emitting device with 1-x-y P (0≦x≦1, 0≦y≦1), between the light emitting layer and the substrate,
A light reflecting layer is formed from alternately laminated films having different compositions.

(作用) 本発明では、■−v族化合物半導体としては比較的バン
ドギャップの大きいInGaAIPからなる発光層と、
バンドギャップの小さいGaAs等からなる化合物半導
体基板との間に光反射層を設けることにより、発光層か
ら基板側に向かう放射光を光取出し側に反射させること
ができ、これにより光吸収の最大の原因であるバンドギ
ャップの狭いGaAs基板による吸収が避けられる。従
って、素子外部への光取出し効率が向上し、これまで困
難であった実用レベルの輝度の緑色LEDが実現可能と
なる。
(Function) In the present invention, ■ a light-emitting layer made of InGaAIP, which has a relatively large bandgap as a group V compound semiconductor;
By providing a light reflection layer between the compound semiconductor substrate made of GaAs or the like with a small bandgap, the emitted light directed from the light emitting layer toward the substrate side can be reflected to the light extraction side, thereby maximizing the light absorption. Absorption by the narrow bandgap GaAs substrate, which is the cause, can be avoided. Therefore, the efficiency of extracting light to the outside of the element is improved, and it becomes possible to realize a green LED with a practical level of brightness, which has been difficult until now.

ここで、光反射層としては異なる組成の多層膜(交互積
層膜)を用いるが、この交互積層の周期は発光波長程度
にする。反射率を高くする観点からは、交互積層の周期
を発光波長λに対して、λ/2.λ/8,2λ等にする
のが望ましい。また、コンタクト層における光吸収を低
減する目的で、コンタクト層のバンドギャップを大きく
し放射光に対して透明にすれば、光取出し効率のさらな
る向上をはかることが可能である。ところが、バンドギ
ャップの大きなコンタクト層を形成する代わりに、バン
ドギャップは小さくても間接遷移型半導体材料を用いる
ことによりて、光吸収を少なくして且つ発光層上への成
長を容易にすることが可能である。
Here, a multilayer film (alternately laminated film) having different compositions is used as the light reflecting layer, and the period of this alternately laminated film is set to be approximately the wavelength of light emission. From the viewpoint of increasing the reflectance, the period of alternate lamination should be set to λ/2. It is desirable to set it to λ/8, 2λ, etc. Further, in order to reduce light absorption in the contact layer, if the band gap of the contact layer is increased to make it transparent to emitted light, it is possible to further improve the light extraction efficiency. However, instead of forming a contact layer with a large band gap, it is possible to reduce light absorption and facilitate growth on the light emitting layer by using an indirect transition type semiconductor material even though the band gap is small. It is possible.

(実施例) 以下、本発明の詳細を図示の実施例によって説明する。(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

第1図は1本発明の一実施例に係わるLEDの概略構造
を示す断面図であり、基板と発光層との間に光反射層を
設け、基板による光吸収を回避したものである。
FIG. 1 is a sectional view showing a schematic structure of an LED according to an embodiment of the present invention, in which a light reflecting layer is provided between a substrate and a light emitting layer to avoid light absorption by the substrate.

図中11はp−GaAs基板であり、この基板11上に
はp−GaAsバッファ層12及びp−1nGaP中間
バンドギャップ層13が成長形成され、さらにこの中間
バンドギャップ層13上にp−InAIPとp −1n
 G a A I Pの多層構造からなる光反射層14
が成長形成されている。光反射層14上には、p−1n
^IPクラッド層15.InGaAIP活性層16及び
n−1nAIPクラッド層17から構成されるダブルへ
テロ構造の発光層が成長形成され、この発光層上にn−
1nAIPコンタクト層18が成長形成されている。な
お、図中21はp側電極(光取出し側電極)、22はn
側電極を示している。
In the figure, 11 is a p-GaAs substrate, on which a p-GaAs buffer layer 12 and a p-1nGaP intermediate bandgap layer 13 are grown, and further on this intermediate bandgap layer 13, p-InAIP and p-InAIP are grown. p −1n
Light reflecting layer 14 consisting of a multilayer structure of G.A.I.P.
is growing and forming. On the light reflecting layer 14, p-1n
^IP cladding layer 15. A double heterostructure light-emitting layer consisting of an InGaAIP active layer 16 and an n-1nAIP cladding layer 17 is grown, and n-
A 1nAIP contact layer 18 is grown. In the figure, 21 is the p-side electrode (light extraction side electrode), and 22 is the n-side electrode.
The side electrode is shown.

ここで、中間バンドギャップ層13は、バッファ層12
と光反射層14との間の大きなバンドギャップ差による
オーミック接合の阻害を防止するものである。光反射層
14は反射率を高くするために、発光波長の1/2程度
の積層周期にした。また、コンタクト層18のバンドギ
ャップは活性層16のバンドギャップよりも大きく、発
光波長に対して透明となるようにした。
Here, the intermediate bandgap layer 13 is the buffer layer 12
This prevents the ohmic junction from being inhibited due to a large band gap difference between the light reflecting layer 14 and the light reflecting layer 14. In order to increase the reflectance of the light reflecting layer 14, the lamination period was set to about 1/2 of the emission wavelength. Further, the band gap of the contact layer 18 is larger than that of the active layer 16, so that it is transparent to the emission wavelength.

次に、上記素子の製造方法について具体的に説明する。Next, a method for manufacturing the above element will be specifically explained.

各半導体層は有機金属化学気相成長法(MOCV D法
)により成長させた。原料にはメチル系■族有機金属と
してのトリメチルインジウム(TMI)   トリメチ
ルガリウム(TMG)、及びトリメチルアルミニウム(
TMA)を用い、V放水素化物としてのアルシン(AS
H3)及びフォスフイン(PH3)を用い、水素をキャ
リアガスとて石英製反応管に反応性ガスを輸送してSi
Cコーティングしたグラファイトサセプタ上に設置した
基板に結晶を成長させた。反応管内部の圧力は083〜
1気圧であり、基板温度は700℃程度に外部より高周
波加熱される。基板にはZnドープ、キャリア濃度3X
10180Il−3のp−GaAsを用いた。
Each semiconductor layer was grown by metal organic chemical vapor deposition (MOCVD). The raw materials include trimethylindium (TMI), trimethylgallium (TMG), and trimethylaluminum (TMI) as methyl group II organic metals.
Arsine (AS) as a V-hydrogen
Si
Crystals were grown on a substrate placed on a C-coated graphite susceptor. The pressure inside the reaction tube is 083~
The pressure is 1 atm, and the substrate temperature is externally heated by high frequency to about 700°C. Substrate is Zn doped, carrier concentration 3X
10180Il-3 p-GaAs was used.

基板の面方位は(100)である。The plane orientation of the substrate is (100).

始めにp−GaAs基板11上にp−CaAs(Znド
ープ、  3 X 10”cm−’)バッファ層12を
2pm、p −I n、、、Gao、s P  (Zn
ドープ、  3 X 101B101Ba中間バンドギ
ャップ層13を0.5μm成長させる。後者は、GaA
sとInAIPのバンドギャップの中間のバンドギャッ
プになる層であり、大きなバンドギャップ差による接合
の非オーム性を防止する。この上にp−In0.、AI
。、、Pと p −I no、5 G ao、2 A 1 。、3 
Pの交互積層からなる光反射層14を5μm形成する。
First, a p-CaAs (Zn-doped, 3 x 10"cm-') buffer layer 12 is formed on a p-GaAs substrate 11 with a thickness of 2 pm, p-I n,..., Gao, s P (Zn
A doped, 3×101B101Ba intermediate bandgap layer 13 is grown to 0.5 μm. The latter is GaA
This layer has a band gap between that of InAIP and InAIP, and prevents non-ohmic properties of the junction due to a large band gap difference. On top of this, p-In0. , A.I.
. ,,P and p-I no, 5 Gao, 2 A 1 . ,3
A light reflecting layer 14 made of alternately laminated layers of P is formed to a thickness of 5 μm.

この部分は、Znドープ、キャリア濃度I X 10”
cab−’であり放射光を効率良く反射するために半導
体内の波長の約172の積層周期の1000人で交互積
層する。
This part is Zn-doped and has a carrier concentration of I x 10"
cab-', and in order to efficiently reflect the emitted light, 1000 layers are alternately stacked at a stacking period of about 172 wavelengths within the semiconductor.

次いで、光反射層14上にp− Ino、s A 1o、5  P  (Znドープ、I
XlX1018a’、2um)クラッド層15.アンド
ープIno、5GaO125A I 0.25P (0
,5μm)活性層15.n−1n、、5 A1..5 
P (Seドープ。
Next, p-Ino, sA 1o, 5P (Zn doped, I
XlX1018a', 2um) cladding layer 15. Undoped Ino, 5GaO125A I 0.25P (0
, 5 μm) active layer 15. n-1n, 5 A1. .. 5
P (Se doped.

I X 10I10l8’、  2 p m )クラッ
ド層17からなるダブルへテロ構造を形成する。その後
、発光波長に対して透明なn−1no、5 AIo、5
 pコンタクト層(Seドープ、  3 X 1010
18a’) 18を5μm成長させる。最後に、基板1
1の裏面及びコンタクト層18の上面にIn電極21゜
22を装着することによって、緑色領域で発光するLE
Dが完成することになる。
I x 10I10l8', 2 p m ) A double heterostructure consisting of the cladding layer 17 is formed. After that, n-1no,5 AIo,5 which is transparent to the emission wavelength
p contact layer (Se doped, 3 x 1010
18a') Grow 18 to 5 μm. Finally, board 1
By attaching In electrodes 21 and 22 to the back surface of the contact layer 1 and the top surface of the contact layer 18, an LE that emits light in the green region
D will be completed.

かくして製造されたLEDにおいては、ダブルへテロ構
造部からなる発光層で発生した光はn側電極(光取出し
側電極)22側及び基板11側に向かうことになる。基
板11側に向かう放射光は光反射層14で効率良く反射
され、光取出し電極22側に向かう。このため、基板1
1による光吸収を防止することができ、光反射層14の
ない場合と比べて著しく輝度の向上した50mcd程度
の緑色LEDが実現できた。また、光取出し側の電極(
コンタクト層18)を高濃度にドープし易いn型とする
ことにより、電流の狭窄の少ない良好な素子が実現可能
になる。
In the LED manufactured in this way, light generated in the light emitting layer consisting of the double heterostructure section is directed toward the n-side electrode (light extraction side electrode) 22 side and the substrate 11 side. The emitted light directed toward the substrate 11 side is efficiently reflected by the light reflection layer 14 and directed toward the light extraction electrode 22 side. For this reason, the substrate 1
It was possible to prevent the light absorption caused by the light reflection layer 14, and to realize a green LED of approximately 50 mcd, which has significantly improved brightness compared to the case without the light reflection layer 14. In addition, the electrode on the light extraction side (
By making the contact layer 18) n-type, which can be easily doped with a high concentration, a good element with less current confinement can be realized.

このように本実施例によれば、特別な基板を持ちいずと
も、高品質で安価なGaAsという比較的バンドギャッ
プの狭い基板上に、光吸収を抑える多層構造の光反射層
14を形成し、さらにInGaAIPからなる発光層(
15〜17)を成長させることにより、緑色領域で発光
する高輝度のLEDを作成することができた。
As described above, according to this embodiment, the light reflection layer 14 having a multilayer structure that suppresses light absorption can be formed on a high-quality and inexpensive GaAs substrate with a relatively narrow band gap, without using a special substrate. , and a light-emitting layer made of InGaAIP (
15 to 17), it was possible to create a high-intensity LED that emits light in the green region.

このような方法で比較的低コストで緑色LEDが量産で
きることは、デイスプレィ、光通信等の情報産業への貢
献が極めて大である。
The fact that green LEDs can be mass-produced at relatively low cost using such a method will greatly contribute to information industries such as displays and optical communications.

なお、この実施例では多層構造を持つ光反射層の交互積
層の周期を発光波長の約172とじたが2/1 、1/
l 、 1/4 、1/8にすることも同様に効果が大
きく、光反射層自体の厚さも3μm程度でも十分である
。また、コンタクト層も発光波長に対して透明な組成1
層であればよい。
In this example, the period of alternately laminated light reflecting layers having a multilayer structure was set to about 172 of the emission wavelength, but the period was set to 2/1, 1/
Similarly, setting the thickness to l, 1/4, or 1/8 has a great effect, and a thickness of about 3 μm for the light-reflecting layer itself is also sufficient. In addition, the contact layer also has a composition 1 that is transparent to the emission wavelength.
Any layer is fine.

第2図乃至第5図は、それぞれ本発明の他の実施例の概
略構造を示す断面図である。
FIGS. 2 to 5 are cross-sectional views showing schematic structures of other embodiments of the present invention.

第2図の実施例は先に説明した第1図の実施例において
、最後に成長させるコンタクト層を発光波長に対して透
明な組成のn−n−1nGaAIP(ドープ、3X10
”cm−’、5.czm)としたものである。このコン
タクト層28の組成はI n、、4Ga、、A 1..
4Pであり、1nAIPと比較して成長が容易である。
The embodiment shown in FIG. 2 differs from the embodiment shown in FIG.
"cm-', 5.czm). The composition of this contact layer 28 is In, 4Ga, A 1..
It is 4P and easier to grow than 1nAIP.

他の層は、全て先の実施例と同じものである。All other layers are the same as in the previous example.

第3図の実施例は、発光層をダブルへテロ構造ではな(
p  I nO,5A 1o、s P (Znドープ、
  5 X 1017cmづ、2om>35とn −I
 n、、、 Ga、、2.A 1..25P  (S 
eドープ。
In the embodiment shown in FIG. 3, the light-emitting layer is not a double heterostructure (
p I nO,5A 1o,s P (Zn doped,
5 x 1017cm, 2om>35 and n-I
n, , Ga, 2. A1. .. 25P (S
e-dope.

2 X 10”cg+−’、  2 p m ) 36
からなるシングルへテロ構造としたものである。この場
合、構造がより簡素化しているので比較的容易に吸収損
失のないLEDが作成できた。コンタクト層28は、第
2図の実施例と同様にInAIPと比較して成長の容易
なn−1nGaAIPとした。
2 x 10"cg+-', 2pm) 36
It has a single heterostructure consisting of. In this case, since the structure was simpler, an LED without absorption loss could be produced relatively easily. The contact layer 28 was made of n-1nGaAIP, which is easier to grow than InAIP, as in the embodiment shown in FIG.

第4図の実施例は、第1図の実施例におけるコンタクト
層の代わりに、n−GaAIAs(Seドープ、  5
XIO180m−3,3μm) コンタクト層48を採
用した例である。このコンタクト層48は、Gao、2
A to、8 AsとA1組成を多くし、GaAsより
もバンドギャップを広いものとした。この組成では、間
接遷移型となり吸収係数も小さく、発光波長に対する吸
収係数は5 X 102cm−’程度とGaAsの1/
100に過ぎない。つまり、コンタクト層48のバンド
ギャップは発光波長に相当するバンドギャップよりも小
さいが間接遷移型としているので、該層48における光
吸収を極めて少なくすることができる。
The embodiment of FIG. 4 uses n-GaAIAs (Se-doped, 5
This is an example in which a contact layer 48 (XIO180m-3, 3 μm) is used. This contact layer 48 has Gao,2
The A to, 8 As and A1 compositions were increased to make the band gap wider than that of GaAs. With this composition, it becomes an indirect transition type and the absorption coefficient is small, and the absorption coefficient for the emission wavelength is about 5 x 102 cm-', which is 1/1 of that of GaAs.
It's only 100. In other words, since the contact layer 48 has an indirect transition type, although the band gap is smaller than the band gap corresponding to the emission wavelength, light absorption in the contact layer 48 can be extremely reduced.

この実施例の場合、コンタクト層48を成長速度の早い
GaAlAsにすることにより素子の作成が容易になり
低コスト化がはかれる。この方法でも十分に輝度の高い
LEDが作成できた。また、必要に応じてこの層の一部
を取り去り、さらに吸収を減少させることも可能である
In this embodiment, by forming the contact layer 48 using GaAlAs, which has a high growth rate, the device can be easily manufactured and the cost can be reduced. Even with this method, an LED with sufficiently high brightness could be produced. It is also possible to remove part of this layer to further reduce absorption if desired.

第5図の実施例は、光反射層の組成を変えた例であり、
1000人の周期の共にSeドープ、2X 1018c
ar−3のp−Gao、3 A l。、、Asとp−G
 a O,2A I o、s A Sの多層構造からな
る光反射層54を用いたものである。発光層の構造は、
第1図の実施例と全く同じである。GaAlAs層も交
互積層することにより効率の高い反射層を形成できる。
The example shown in FIG. 5 is an example in which the composition of the light reflecting layer is changed,
Se-doped with 1000 cycles, 2X 1018c
ar-3 p-Gao, 3A l. ,, As and p-G
A light reflecting layer 54 having a multilayer structure of a O, 2 A I o, and S A S is used. The structure of the light emitting layer is
This is exactly the same as the embodiment shown in FIG. A highly efficient reflective layer can also be formed by alternately stacking GaAlAs layers.

ここではさらにコンタクト層48をn−GaAlAsと
することにより厚い膜の成長に向かないI nA I 
Pの成長を極カ避けることができるため、さらに製造コ
ストの低下をもたらす。また、GaAlAsのバンドギ
ャップがInGaAIPより小さ(GaAsよりも大き
いことから、光反射層54と基板11との間に中間バン
ドギャップ層を形成する必要がなくなる利点もある。
Here, the contact layer 48 is made of n-GaAlAs, which is not suitable for growing a thick film.
Since the growth of P can be avoided to a large extent, manufacturing costs are further reduced. Furthermore, since the bandgap of GaAlAs is smaller than that of InGaAIP (larger than that of GaAs), there is an advantage that there is no need to form an intermediate bandgap layer between the light reflective layer 54 and the substrate 11.

なお、本発明は上述した各実施例に限定されるものでは
ない。いずれの実施例においても電極の形、数、配置、
また基板の面方位、さらに半導体層の厚さは、仕様に応
じて適宜変更可能である。また、発光層部分の構造もペ
テロ構造に限らずホモ接合も可能である。InGaP中
間バンドギャップ層は、GaAs基板と発光層のInG
aAsPとの大きなバンドギャップ差によるオーミック
接合の阻害を防止する目的で形成するものであり、両者
の中間のバンドギャップを持つ他の半導体も同様に利用
できる。さらにバッファ層側とクラッド側で組成を変え
濃度勾配を付ける方法も有効である。
Note that the present invention is not limited to the embodiments described above. In any embodiment, the shape, number, arrangement of electrodes,
Furthermore, the surface orientation of the substrate and the thickness of the semiconductor layer can be changed as appropriate depending on specifications. Further, the structure of the light-emitting layer portion is not limited to the Peter structure, and a homojunction is also possible. The InGaP intermediate bandgap layer consists of a GaAs substrate and an InG light emitting layer.
It is formed for the purpose of preventing the ohmic junction from being inhibited due to the large band gap difference with aAsP, and other semiconductors having a band gap between the two can be used in the same way. Furthermore, it is also effective to change the composition on the buffer layer side and the cladding side to create a concentration gradient.

実施例ではクラッド層にInAIPを用いたが、発光波
長に対して透明な組成の1nGaAIFとすることも可
能である。また、各層の格子整合性を改善するため、或
いはバンドギャップを選択するために、sbを混合した
り、GaAs層やGaAlAs層にPやInを混合して
もよく、その逆に1nGaAIPをInGaPとしても
よい。その他、本発明の要旨を逸脱しない範囲で、種々
変形して実施することができる。
In the embodiment, InAIP was used for the cladding layer, but it is also possible to use 1nGaAIF, which has a composition transparent to the emission wavelength. Furthermore, in order to improve the lattice matching of each layer or to select the band gap, sb may be mixed, P or In may be mixed into the GaAs layer or GaAlAs layer, or vice versa, 1nGaAIP may be mixed with InGaP. Good too. In addition, various modifications can be made without departing from the gist of the present invention.

[発明の効果] 以上詳述したように本発明によれば、基板と発光層との
間に放射光を反射させる光反射層を形成し、先取出しの
低効率という問題を光反射層で基板側への光を取出し側
に反射させる方法で解決しているので、基板における放
射光の吸収を低減することができ、輝度の向上をはかり
得る半導体発光素子を実現することができる。
[Effects of the Invention] As detailed above, according to the present invention, a light reflection layer that reflects emitted light is formed between the substrate and the light emitting layer, and the problem of low efficiency of pre-extraction can be solved by forming the light reflection layer on the substrate with the light reflection layer. Since the problem is solved by a method of reflecting the light toward the side toward the output side, it is possible to reduce the absorption of the emitted light in the substrate, and it is possible to realize a semiconductor light-emitting device that can improve the brightness.

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

第1図は本発明の一実施例を説明するためのもので、ダ
ブルへテロ構造の発光層。 InGaAIP/InAIFの交互積層膜からなる光反
射層及びInAIPコンタクト層を持つLEDの素子構
造を示す断面図、第2図乃至第5図はそれぞれ本発明の
他の実施例を説明するためのもので、第2図はコンタク
ト層をInGaAIPにした素子構造を示す断面図、第
3図はシングルへテロ構造の発光層を持つ素子構造を示
す断面図、第4図はコンタクト層をGaA 】Asにし
た素子構造を示す断面図、第5図は光反射層をGaA 
IAsの多層構造とした素子構造を示す断面図である。 11− p −G a A s基板 12・・・p−GaAsバッファ層 13・・・p−InGaP中間バンドギャップ層14−
1nAIP/InGaAIPの多層構造(光反射層15
−−− p −I n A I Pクラッド層16−p
 −I n G a A I P活性層17−= n 
−1n A I Pクララド層18・・・n−1nAI
Pコンタクト層21.22・・・電極 28・・・n−InGaAIPコンタクト層35−p 
−1n A I P層
FIG. 1 is for explaining one embodiment of the present invention, and shows a light emitting layer with a double heterostructure. 2 to 5 are cross-sectional views showing the element structure of an LED having a light reflection layer and an InAIP contact layer made of alternately laminated films of InGaAIP/InAIF, and are for explaining other embodiments of the present invention, respectively. , Fig. 2 is a cross-sectional view showing a device structure with a contact layer made of InGaAIP, Fig. 3 is a cross-sectional view showing a device structure with a single heterostructure light emitting layer, and Fig. 4 is a cross-sectional view showing a device structure with a contact layer made of GaA]As. A cross-sectional view showing the device structure, FIG. 5 shows a light reflecting layer made of GaA.
FIG. 2 is a cross-sectional view showing an element structure having a multilayer structure of IAs. 11-p-GaAs substrate 12...p-GaAs buffer layer 13...p-InGaP intermediate bandgap layer 14-
1nAIP/InGaAIP multilayer structure (light reflective layer 15
--- p -I n A I P cladding layer 16-p
-InGaAIP active layer 17-=n
-1n AI P Clarado layer 18...n-1nAI
P contact layer 21.22...electrode 28...n-InGaAIP contact layer 35-p
-1n AIP layer

Claims (2)

【特許請求の範囲】[Claims] (1)半導体基板上にpn接合からなる発光層を有し、
該発光層を形成する半導体をIn_XGa_YAl_1
_−_X_−_YP(0≦x≦1、0≦y≦1)とした
半導体発光素子において、前記発光層と基板との間に、
異なる組成の交互積層膜からなる光反射層を形成してな
ることを特徴とする半導体発光素子。
(1) Having a light emitting layer made of a pn junction on a semiconductor substrate,
The semiconductor forming the light emitting layer is In_XGa_YAl_1
In the semiconductor light emitting device with ___X_-_YP (0≦x≦1, 0≦y≦1), between the light emitting layer and the substrate,
A semiconductor light emitting device characterized by forming a light reflecting layer consisting of alternately laminated films of different compositions.
(2)前記発光層と光取出し側電極との間に、前記発光
層における放射光のエネルギーに相当するバンドギャッ
プより小さいバンドギャップを有する、間接遷移型半導
体からなるコンタクト層を形成したことを特徴とする請
求項1記載の半導体発光素子。
(2) A contact layer made of an indirect transition type semiconductor having a band gap smaller than a band gap corresponding to the energy of emitted light in the light emitting layer is formed between the light emitting layer and the light extraction side electrode. The semiconductor light emitting device according to claim 1.
JP25045089A 1989-09-28 1989-09-28 Semiconductor light emitting device Expired - Lifetime JP3141888B2 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP25045089A JP3141888B2 (en) 1989-09-28 1989-09-28 Semiconductor light emitting device
US07/588,858 US5103271A (en) 1989-09-28 1990-09-27 Semiconductor light emitting device and method of fabricating the same
DE69025842T DE69025842T2 (en) 1989-09-28 1990-09-28 Semiconductor light emitting device and method of manufacturing the same
EP90310680A EP0420691B1 (en) 1989-09-28 1990-09-28 Semiconductor light-emitting device and method of fabricating the same
US07/819,976 US5235194A (en) 1989-09-28 1992-01-13 Semiconductor light-emitting device with InGaAlP
US08/058,221 US5317167A (en) 1989-09-28 1993-05-10 Semiconductor light-emitting device with InGaAlp

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP25045089A JP3141888B2 (en) 1989-09-28 1989-09-28 Semiconductor light emitting device

Publications (2)

Publication Number Publication Date
JPH03114277A true JPH03114277A (en) 1991-05-15
JP3141888B2 JP3141888B2 (en) 2001-03-07

Family

ID=17208060

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Link
JP (1) JP3141888B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5537433A (en) * 1993-07-22 1996-07-16 Sharp Kabushiki Kaisha Semiconductor light emitter
JP2012190985A (en) * 2011-03-10 2012-10-04 Stanley Electric Co Ltd Semiconductor light-emitting element and manufacturing method for the same
JP2014027310A (en) * 2013-11-01 2014-02-06 Toshiba Corp Light-emitting element

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5537433A (en) * 1993-07-22 1996-07-16 Sharp Kabushiki Kaisha Semiconductor light emitter
JP2012190985A (en) * 2011-03-10 2012-10-04 Stanley Electric Co Ltd Semiconductor light-emitting element and manufacturing method for the same
JP2014027310A (en) * 2013-11-01 2014-02-06 Toshiba Corp Light-emitting element

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