JPH0373577A - Light emitting diode - Google Patents
Light emitting diodeInfo
- Publication number
- JPH0373577A JPH0373577A JP1210312A JP21031289A JPH0373577A JP H0373577 A JPH0373577 A JP H0373577A JP 1210312 A JP1210312 A JP 1210312A JP 21031289 A JP21031289 A JP 21031289A JP H0373577 A JPH0373577 A JP H0373577A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- type
- active layer
- ingaasp
- undoped
- 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
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 238000005253 cladding Methods 0.000 claims description 16
- 239000012535 impurity Substances 0.000 claims description 5
- 240000002329 Inga feuillei Species 0.000 claims 1
- 239000007791 liquid phase Substances 0.000 abstract description 5
- 239000000969 carrier Substances 0.000 abstract description 3
- 239000002019 doping agent Substances 0.000 abstract description 3
- 239000011701 zinc Substances 0.000 description 12
- 238000009792 diffusion process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 125000005842 heteroatom Chemical group 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Led Devices (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は発光ダイオードに関し、特にＩｎＰ基板上に形
成した、Ｉ ｎＰ／Ｉ ｎＧａＡｓＰダブルヘテロ型発
光ダイオードの構造に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light emitting diode, and more particularly to the structure of an InP/InGaAsP double hetero type light emitting diode formed on an InP substrate.
通信用に用いられるＩ ｎＰ／Ｉ ｎＧａＡｓＰダブル
へテロ型発光ダイオード（以下、素子と略記する）の中
で応答速度が速いことを特徴とする素子として、活性層
に５ Ｘ １０１ｇｃｍ−３以上の高濃度のＰ型ドーパ
ントを混入させて形成した素子がある。従来、上述の素
子は、第２図に示すようにＮ型ＩｎＰ基板１上に、濃度
がＩ Ｘ １０１８ｃｘｉ−’程度のＮ型ＩｎＰクラッ
ド層２と、濃度が５Ｘ１０１ｇＣａｌ−’以上のＺｎ（
亜鉛〉をドープしたＩ ｎＧａＡｓＰ活性Ａｓ上Ｐ型Ｉ
ｎＰクラッド層５及びＰ型ＩｎＧａＡｓＰキャップ層６
を形成した構造を有し、またこれらの各半導体層は液相
エピタキシャル成長によって形成していた。Among the InP/InGaAsP double hetero type light emitting diodes (hereinafter abbreviated as devices) used for communication, this device is characterized by a fast response speed, and is characterized by a high response speed of 5 x 101 gcm-3 or more in the active layer. There are devices formed by mixing a high concentration of P-type dopants. Conventionally, as shown in FIG. 2, the above-mentioned device has an N-type InP cladding layer 2 on an N-type InP substrate 1 with a concentration of about I x 1018cxi-' and a Zn(
Zinc doped I nGaAsP P-type I on active As
nP cladding layer 5 and P-type InGaAsP cap layer 6
Each of these semiconductor layers was formed by liquid phase epitaxial growth.
上述の従来の発光ダイオードは、ＩｎＧａＡｓＰ活性層
３に高濃度のＺｎを混入させているため、活性層形成後
の液相エピタキシャル成長中にＩｎＧａＡｓＰ活性層４
中のＺｎがＮ型ＩｎＰりラッド層２中に拡散し、Ｎ型Ｉ
ｎ９７９７１層２のうちのＩｎＧａＡｓＰ活性層４に近
い側の一部がＰ型に反転し、ＰＮ接合がＮ型ＩｎＰクラ
ッド層２中に形成される。この結果、ＩｎＧａＡｓＰ活
性層４中へのキャリアの閉じ込め効率が悪化し、素子の
発光効率が低下するという欠点があった。また、Ｚｎの
拡散をできるだけおさえるために活性層より上部のエピ
タキシャル層（Ｐ型クラッド層及びキャップ層〉の成長
をスパークリング法により短時間に終らせる方法もある
が、スパークリング法は、メルトの均一性が悪いために
、均一性の良いエピタキシャル層を得ることが困難であ
り、量産性に欠けていた。一方ＺｎのＮ型Ｉｎ９７９７
１層２への拡散を押えるために、Ｎ濃度を高濃度にする
方法もあるが、高濃度にドープされたＩｎＰ層は、表面
に凹凸となるいわゆるテラスが発生する。特に２ Ｘ
ｌ □ ｔａ備−、にドーピングされたＩｎＰ層のテラ
スの段差は大きい、そして、この凸部のＩｎＰはＩｎＰ
中のＰ（リン）が解離しやすく、例えばテラスの激しい
ＩｎＰクラッド層上に活性層を形成した場合、ＩｎＰ中
のＰが解離した部分より活性層中に転位が発生し、素子
の寿命に重大の支障をきたすという欠点があった。In the conventional light emitting diode described above, since a high concentration of Zn is mixed into the InGaAsP active layer 3, the InGaAsP active layer 4 is mixed during liquid phase epitaxial growth after forming the active layer.
The Zn inside diffuses into the N-type InP layer 2, and the Zn becomes the N-type I
A part of the n97971 layer 2 on the side closer to the InGaAsP active layer 4 is inverted to P type, and a PN junction is formed in the N type InP cladding layer 2. As a result, the efficiency of confining carriers in the InGaAsP active layer 4 deteriorates, resulting in a disadvantage that the light emitting efficiency of the device decreases. In addition, in order to suppress the diffusion of Zn as much as possible, there is a method in which the growth of the epitaxial layer (P-type cladding layer and cap layer) above the active layer is completed in a short time using the sparkling method. This made it difficult to obtain an epitaxial layer with good uniformity and lacked mass productivity.On the other hand, Zn N-type In9797
In order to suppress the diffusion into layer 1 and layer 2, there is a method of increasing the N concentration, but a highly doped InP layer produces uneven surfaces, ie, so-called terraces. Especially 2X
The step of the terrace of the InP layer doped with l □ ta is large, and the InP of this convex part is InP
P (phosphorus) in the InP is easily dissociated, and for example, if an active layer is formed on an InP cladding layer with severe terraces, dislocations will occur in the active layer from the parts where P in InP has dissociated, which will be critical to the life of the device. It had the disadvantage of causing problems.
本発明は上述の問題点を解決し、量産性に富み、発光効
率の良い発光ダイオードを得ることを目的として、いる
。The present invention aims to solve the above-mentioned problems and provide a light-emitting diode that can be easily mass-produced and has good luminous efficiency.
本発明の発光ダイオードは、Ｎ型ＩｎＰ基板上にＮ型Ｉ
ｎＰクラッド層と、アンドープでかつ活性層と同じ組成
をもつＩｎＧａＡｓＰ層、不純物濃度が５ Ｘ Ｉ Ｑ
１８ｃ１１−３以上のＰ型ＩｎＧａＡｓＰ活性層、Ｐ
型ＩｎＰクラッド層およびＰ型ＩｎＧａＡｓＰキャップ
層を順次積層した構造を有している。The light emitting diode of the present invention has an N-type I on an N-type InP substrate.
An nP cladding layer, an undoped InGaAsP layer with the same composition as the active layer, and an impurity concentration of 5
P-type InGaAsP active layer of 18c11-3 or higher, P
It has a structure in which an InP type cladding layer and a P type InGaAsP cap layer are sequentially laminated.
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図に、本発明の第１の実施例の素子の断面図を示す
。FIG. 1 shows a sectional view of a device according to a first embodiment of the present invention.
本発明の第１の実施例の素子は、Ｎ型ＩｎＰ基板１上に
厚さ１μｍ、濃度Ｉ Ｘ １０ ”ｃｍ’″ＳのＮ型Ｉ
ｎ９７９７１層２、厚さ０．３μｍのアンドープのＩ
ｎＧａＡｓＰ層３、厚さ０．３．ｃｚｍ、不純物濃度１
×１０１９ｃｍ−５のＰ型Ｉ ｎＧａＡｓＰ活性層４、
厚さ１μｍ、不純物濃度５ Ｘ Ｉ Ｏ”ＣＩ＋−’の
Ｐ型ＩｎＰクラッド層５、及び厚さ１．５μｍ、不純物
濃度５ Ｘ Ｉ Ｏ１８ｃｍ−’のＰ型ＩｎＧａＡｓＰ
キャップ層６を順次形成し、さらに円形領域Ｍを除いた
Ｐ型ＩｎＧａＡｓＰキャップ層６の表面に酸化膜７を形
成し、続いて、その上に全面！＠（Ｐ側電極）８を形成
し、また少なくとも円形領域Ｍの下に対応する円形領域
Ｎを除いたＮ型ＩｎＰ基板１の表面にＮ側電極Ｐを形成
した構造を有している。The device of the first embodiment of the present invention has an N-type I layer on an N-type InP substrate 1 with a thickness of 1 μm and a concentration of I x 10 "cm'"S.
n97971 layer 2, undoped I with a thickness of 0.3 μm
nGaAsP layer 3, thickness 0.3. czm, impurity concentration 1
×1019 cm-5 P-type InGaAsP active layer 4,
A P-type InP cladding layer 5 with a thickness of 1 μm and an impurity concentration of 5 X I O"CI+-', and a P-type InGaAsP with a thickness of 1.5 μm and an impurity concentration of 5 X I O 18 cm-'
A cap layer 6 is sequentially formed, and then an oxide film 7 is formed on the surface of the P-type InGaAsP cap layer 6 except for the circular region M, and then the entire surface is covered with the oxide film 7! @(P-side electrode) 8 is formed, and the N-side electrode P is formed on the surface of the N-type InP substrate 1 excluding at least the circular region N corresponding to the bottom of the circular region M.
本素子は、上下を反対にして、Ｎ型ＩｎＰ基板側を上に
してヒートシンクにマウントして使用する。したがって
電流は電極８よりＰ型Ｉ ｎＧａＡｓＰキャップ層６、
Ｐ型ＩｎＰクラッド層５、Ｐ型ＴｎＧａＡｓＰ活性層４
、アンドープＩｎＧａＡｓＰ層３、Ｎ型Ｉｎ９７９７１
層２、及びＮ型基板１を経て電極９へ流れることとなる
。−方Ｐ型Ｉ ｎＧａＡｓＰ活性層４で発生した光は、
Ｎ型Ｉｎ９７９７１層２、Ｎ型ＩｎＰ基板１を経て、円
形領域Ｎより外部へ放射されることとなる。This device is used by being turned upside down and mounted on a heat sink with the N-type InP substrate side facing up. Therefore, the current flows from the electrode 8 to the P-type InGaAsP cap layer 6,
P-type InP cladding layer 5, P-type TnGaAsP active layer 4
, undoped InGaAsP layer 3, N-type In97971
It will flow to the electrode 9 via the layer 2 and the N-type substrate 1. - The light generated in the P-type InGaAsP active layer 4 is
The light passes through the N-type In97971 layer 2 and the N-type InP substrate 1, and is radiated to the outside from the circular region N.
ここで、上述の素子における各半導体層２゜３．４，５
．６は液相エピタキシャル成長によって形成されたもの
であるが、成長中にＩ ｎＧａＡｓＰ活性Ａｓ中のＰ型
ドーパントであるＺｎがアンドープＩｎＧａＡｓＰ層３
に拡散する。従来、このＰＮ接合と活性層の間の距離は
０．４μｍ程度であったが、本実施例では、活性層４を
０．３μｍとし、アンドープのＩｎＧａＡｓＰ層３を０
．３μｍ設けることにより、０．０１μｍ以下と大幅に
縮小することができ、この結果活性層中のキャリアの閉
じ込め効率が向上し、素子の発光効率は従来の約１．２
倍に向上した。Here, each semiconductor layer 2°3.4,5
．． 6 is formed by liquid phase epitaxial growth, and during the growth, Zn, which is a P-type dopant in InGaAsP active As, forms an undoped InGaAsP layer 3.
spread to. Conventionally, the distance between this PN junction and the active layer was about 0.4 μm, but in this example, the active layer 4 was set to 0.3 μm, and the undoped InGaAsP layer 3 was set to 0.3 μm.
．． By providing 3 μm, the size can be significantly reduced to 0.01 μm or less, and as a result, the carrier confinement efficiency in the active layer is improved, and the luminous efficiency of the device is reduced to approximately 1.2 μm compared to the conventional one.
improved twice.
次に、本発明の第２の実施例の素子について説明する。Next, a device according to a second embodiment of the present invention will be explained.
第３図は、本発明第２の実施例の素子の断面図である。FIG. 3 is a sectional view of a device according to a second embodiment of the present invention.
同図に示すように第２の実施例の素子は、第１の実施例
に対し、Ｐ型Ｉ ｎＧａＡｓＰ活性層４の層厚が０．１
μｍ、アンドープＩｎＧａＡｓＰ層３の層厚が０．５μ
ｍと薄くしたこと、さらにＮ側電極９をＮ型１ｎＰ基板
１の表面全面に形成したことの他は第１の実施例と同様
の素子構造となっている。すなわち、第１の実施例の素
子は、いわゆる面発光ダイオードであったのに対し、こ
の第２の実施例の素子は、光が活性層端面１０より直接
外部に放射される端面発光ダイオードである。As shown in the figure, in the device of the second embodiment, the layer thickness of the P-type InGaAsP active layer 4 is 0.1% different from that of the first embodiment.
μm, and the layer thickness of the undoped InGaAsP layer 3 is 0.5 μm.
The device structure is the same as that of the first embodiment except that the thickness is made as thin as m and that the N-side electrode 9 is formed over the entire surface of the N-type 1nP substrate 1. That is, while the element of the first embodiment was a so-called surface emitting diode, the element of the second embodiment is an edge emitting diode in which light is emitted directly to the outside from the end face 10 of the active layer. .
以上説明したように、本発明の素子は、高濃度のＰ型Ｉ
ｎＧａＡｓＰ活性層とＮ型ＩｎＰクラッド層との境界
にアンドープでかつ活性層と同じ組成のＸ ｎＧａＡｓ
Ｐ層を設け、この活性層厚と、アンドープＩｎＧａＡｓ
Ｐ層厚は、Ｚｎの濃度による拡散距離の関係から、最適
化し、液相エピタキシャル成長中にＰ型活性層中のＺｎ
がアンドープＩｎＧａＡｓＰ層へ拡散した後、有効な活
性層厚をもつ構造とすることにより、Ｎ型ＩｎＰクラッ
ド層中へのＺｎの拡散を押えることができる。As explained above, the device of the present invention has a high concentration of P-type I
Undoped X nGaAs having the same composition as the active layer is placed at the boundary between the nGaAsP active layer and the N-type InP cladding layer.
A P layer is provided, and the active layer thickness and undoped InGaAs
The P layer thickness is optimized from the relationship between the diffusion distance depending on the Zn concentration, and the Zn in the P-type active layer is
After diffusion of Zn into the undoped InGaAsP layer, by creating a structure with an effective active layer thickness, diffusion of Zn into the N-type InP cladding layer can be suppressed.
この結果、活性層中へのキャリアの閉じ込め効率が向上
し、従来の素子より発光効率を向上できる効果がある。As a result, the efficiency of confining carriers in the active layer is improved, which has the effect of improving luminous efficiency compared to conventional elements.
また、本構造によれば、成長速度の遅いオーバーシード
法による均一性の高い成長法を用いることができ、量産
性の点からも優れた効果が得られる。Further, according to the present structure, it is possible to use a highly uniform growth method using an overseeding method with a slow growth rate, and an excellent effect can be obtained from the viewpoint of mass production.
第１図及び第３図は本発明の一実施例の素子断面図、第
２図は従来の素子の断面図の一部である０図中において
、
１・・・Ｎ型ＩｎＰ基板、２・・・Ｎ型ＩｎＰクラッド
層、３・・・アンドープＩｎＧａＡｓＰ層、４・・・Ｐ
型ＩｎＧａＡｓＰ活性層、５−Ｐ型ＩｎＰクラッド層、
６・・・Ｐ型ＩｎＧａＡｓＰキャップ層、７・・・酸化
膜、８・・・Ｐ側電極、９・・・Ｎ側電極を示す。1 and 3 are cross-sectional views of a device according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of a conventional device. ...N-type InP cladding layer, 3...Undoped InGaAsP layer, 4...P
type InGaAsP active layer, 5-P type InP cladding layer,
6... P-type InGaAsP cap layer, 7... Oxide film, 8... P-side electrode, 9... N-side electrode.
Claims (1)
濃度が５×１０＾１＾８ｃｍ＾−＾３以上のＰ型ＩｎＧ
ａＡｓＰ活性層およびＰ型ＩｎＰクラッド層、ＩｎＧａ
ＡｓＰキャップ層を順次積層した構造を有する発光ダイ
オードにおいて、Ｐ型ＩｎＧａＡｓＰ活性層とＮ型Ｉｎ
Ｐクラッド層の間に、アンドープでかつ活性層と同じ組
成を有するＩｎＰＧａＡｓＰ層を設けた構造であること
を特徴とする発光ダイオード。An N-type InP cladding layer on an N-type InP substrate and a P-type InG with an impurity concentration of 5 x 10^1^8 cm^-^3 or more
aAsP active layer and P-type InP cladding layer, InGa
In a light emitting diode having a structure in which AsP cap layers are sequentially stacked, a P-type InGaAsP active layer and an N-type In
A light emitting diode characterized in that it has a structure in which an undoped InPGaAsP layer having the same composition as the active layer is provided between P cladding layers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1210312A JPH0373577A (en) | 1989-08-14 | 1989-08-14 | Light emitting diode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1210312A JPH0373577A (en) | 1989-08-14 | 1989-08-14 | Light emitting diode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0373577A true JPH0373577A (en) | 1991-03-28 |
Family
ID=16587330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1210312A Pending JPH0373577A (en) | 1989-08-14 | 1989-08-14 | Light emitting diode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0373577A (en) |
-
1989
- 1989-08-14 JP JP1210312A patent/JPH0373577A/en active Pending
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