JPH0141269B2 - - Google Patents
Info
- Publication number
- JPH0141269B2 JPH0141269B2 JP59060217A JP6021784A JPH0141269B2 JP H0141269 B2 JPH0141269 B2 JP H0141269B2 JP 59060217 A JP59060217 A JP 59060217A JP 6021784 A JP6021784 A JP 6021784A JP H0141269 B2 JPH0141269 B2 JP H0141269B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- quantum well
- gaas
- algaas
- active layer
- 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.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/32—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures
- H01S5/3211—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/32—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures
- H01S5/3211—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities
- H01S5/3215—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures characterised by special cladding layers, e.g. details on band-discontinuities graded composition cladding layers
Landscapes
- Semiconductor Lasers (AREA)
Description
【発明の詳細な説明】
技術分野
本発明は半導体レーザ装置に係り、特に発振閾
値電流を低減し、動作電流を小さくすることが出
来る層構造をもつ量子井戸型レーザ装置に関す
る。DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a semiconductor laser device, and particularly to a quantum well laser device having a layered structure that can reduce the oscillation threshold current and reduce the operating current.
従来技術
活性層を非常に薄くし、量子効果が出るような
厚みまで活性層を薄くした量子井戸型レーザは、
ダブルヘテロ構造のレーザに比べて、発振閾値電
流が低くなる利点を有する。Conventional technology Quantum well lasers have an extremely thin active layer that is thin enough to produce quantum effects.
It has the advantage that the oscillation threshold current is lower than that of a double heterostructure laser.
第１図に従来の量子井戸型レーザ装置を示して
おり、１がGaAs基板であり、その上に順次ｎ―
GaAsバツフア層２、ｎ―AlGaAsクラツド層３、
グレーデツド・コンポジシヨン（graded
composition）層４、活性層５、グレーデツド・
コンポジシヨン層６、ｐ―AlGaAsクラツド層
７、ｐ―GaAsコンタクト層８が備えられてい
る。 Figure 1 shows a conventional quantum well laser device, in which 1 is a GaAs substrate, on which n-
GaAs buffer layer 2, n-AlGaAs cladding layer 3,
graded composition
composition) layer 4, active layer 5, graded
A composition layer 6, a p-AlGaAs cladding layer 7, and a p-GaAs contact layer 8 are provided.
解決すべき問題点
厚みが数100Å以下の極めて薄い活性層をもつ
量子井戸型レーザにおいて、その発振閾値電流に
関する特性は、量子井戸を構成するヘテロ界面の
性質に大きく依存する。即ち、界面近傍で非発光
中心の多い場合は、レーザの活性層に注入された
電流のうち、非発光再結合する割合が多くなり、
閾値電流密度Jthは高くなつてしまう。ところで、
GaAs―AlGaAsヘテロ構造の場合を例にとると、
AlGaAs層の上にGaAsをエピタキシヤル成長さ
せた場合、その逆の場合に比べてヘテロ界面近傍
での特性のよくないことが判つている。したがつ
て第１図の量子井戸構造は、前記２つのヘテロ構
造、すなわち、GaAs上のAlGaAsと、AlGaAs
上のGaAsの２つのヘテロ構造を併せた構造であ
るため、必ず一方のヘテロ界面の特性がよくない
という問題があつた。Problems to be Solved In quantum well lasers that have an extremely thin active layer with a thickness of several hundred angstroms or less, the characteristics related to the oscillation threshold current greatly depend on the properties of the heterointerface that constitutes the quantum well. In other words, if there are many non-radiative centers near the interface, a large proportion of the current injected into the active layer of the laser will be recombined non-radiatively.
The threshold current density J th becomes high. by the way,
Taking the case of GaAs-AlGaAs heterostructure as an example,
It has been found that when GaAs is epitaxially grown on an AlGaAs layer, the properties near the heterointerface are poorer than when vice versa. Therefore, the quantum well structure in FIG. 1 consists of the two heterostructures, namely AlGaAs on GaAs and AlGaAs
Since the structure is a combination of the two GaAs heterostructures described above, there was a problem that one of the heterostructures always had poor characteristics.
発明の目的
本発明は、上記従来の問題を解決し、量子井戸
型レーザ装置の発振電流閾値Jthを低減すること
をを目的とする。OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to reduce the oscillation current threshold J th of a quantum well laser device.
問題点解決の手段
本発明においては、量子井戸型レーザ装置にお
いて、活性層と基板の間に存在するエピタキシヤ
ル層の一部に、レーザ構造を構成する元素と同じ
種類の元素の組合せから成る超格子構造のエピタ
キシヤル層を設ける。その構成により活性層を構
成するヘテロ界面の特性が改善され、Jthが低減
する。Means for Solving Problems In the present invention, in a quantum well laser device, a superimposed layer consisting of a combination of the same types of elements as those constituting the laser structure is added to a part of the epitaxial layer between the active layer and the substrate. An epitaxial layer with a lattice structure is provided. This configuration improves the properties of the heterointerface that constitutes the active layer, and reduces J th .
発明の実施例
第２図は、第１図と同等な量子井戸型レーザ装
置であり、各部の番号は純一しているので特に説
明しない。本実施例においては、３のｎ―
AlGaAsクラツド層の一部にAlGaAsとGaAsの
超格子構造９（この例では５周期）を設けてい
る。ここでは、GaAsが150Å、AlGaAsが150Å
の繰返しの周期をもつ超格子構造９を備える。こ
の様子を第３図にAlの組成比で図示しており、
また第４図にバンドギヤツプ図で示している。こ
のように超格子構造９を入れてやることによつて
活性層５のヘテロ界面が非常に改善される。超格
子構造９を入れた場合、入れない時と比べて閾値
電流Jthが２割程度改善される。第１図、第２図
のそれぞれ本発明を実施していない場合と、実施
している場合のレーザ層構造により、ブロードエ
リアレーザを作製したところ、Jthは従来の第１
図の場合500A／cm2であつたのに対して、本発明
を実施した第２図の場合400A／cm2であつた。な
お、上記各々のレーザウエハは、MBE法を用い
て成長した。主な成長条件は、成長温度；710℃、
成長速度；1.5μm／ｈ（AlGaAsに対して）、ｎ型
ドーパント；Si，ｐ型ドーパント；Beである。Embodiment of the Invention FIG. 2 shows a quantum well type laser device equivalent to that in FIG. 1, and since the numbers of each part are the same, no particular explanation will be given. In this example, 3 n-
A superlattice structure 9 (5 periods in this example) of AlGaAs and GaAs is provided in a part of the AlGaAs cladding layer. Here, GaAs is 150 Å and AlGaAs is 150 Å.
The superlattice structure 9 has a repeating period of . This situation is illustrated in Figure 3 using the Al composition ratio.
It is also shown in a band gap diagram in FIG. By introducing the superlattice structure 9 in this manner, the heterointerface of the active layer 5 is greatly improved. When the superlattice structure 9 is included, the threshold current J th is improved by about 20% compared to when it is not included. When broad area lasers were fabricated using the laser layer structures shown in FIGS. 1 and 2 in which the present invention was not implemented and with the present invention implemented, J th
In the case shown in the figure, it was 500 A/cm 2 , whereas in the case shown in FIG. 2 in which the present invention was implemented, it was 400 A/cm 2 . Note that each of the above laser wafers was grown using the MBE method. The main growth conditions are growth temperature; 710℃;
Growth rate: 1.5 μm/h (for AlGaAs), n-type dopant: Si, p-type dopant: Be.
以上、実施例を示したが、本発明において活性
層の界面がきれいになりJthが低下する理由とし
て次のことが考えられる。 Examples have been shown above, but the following may be considered as the reason why the interface of the active layer becomes clean and J th decreases in the present invention.
(1) 第１図に示す従来の場合、基板１に何らかの
欠陥とか転位とか不純物とかがあり、エピタキ
シヤル成長においてそれが上の方にずつと波及
してくる可能性がある。ところが、第２図のよ
うに途中に超格子層９を入れると、該層に欠陥
等がトラツプされるか、または横に逃がされる
ため上まで波及してこない。(1) In the conventional case shown in FIG. 1, there is a possibility that there are some defects, dislocations, impurities, etc. in the substrate 1, which will gradually spread upward during epitaxial growth. However, when a superlattice layer 9 is inserted in the middle as shown in FIG. 2, defects etc. are trapped in this layer or are allowed to escape laterally, so that they do not spread upward.
(2) 基板１上にエピタキシヤル成長するAlGaAs
のエピタキシヤルの表面レイヤーは必ずしもフ
ラツトではなく、ミクロ的にはいろいろ凸凹が
ある。このため第１図のようにエピタキシヤル
成長したのでは活性層５の界面が凸凹になる。
ところが、第２図のように超格子層９を入れる
と凸凹が該層で緩和され、活性層５の界面がフ
ラツト化される。(2) AlGaAs grown epitaxially on substrate 1
The epitaxial surface layer is not necessarily flat, but has various microscopic irregularities. For this reason, when epitaxial growth is performed as shown in FIG. 1, the interface of the active layer 5 becomes uneven.
However, when a superlattice layer 9 is inserted as shown in FIG. 2, the irregularities are alleviated by the superlattice layer 9, and the interface of the active layer 5 is made flat.
以上２つの理由が従来活性層の界面の特性が悪
く、本発明においてこれが改善される理由と思わ
れる。 The above two reasons are thought to be the reasons why the interface characteristics of the conventional active layer are poor and are improved in the present invention.
以上本発明について詳細に説明したが、本発明
はこれに限るものではなく、種々変形可能であ
り、例えばGaAs―AlGaAs系のみならずInGaAs
―InP系、AlGaInAs―GaAs系等他の系にも本発
明を適用できる。また、超格子構造は先に示した
５周期に限るものでなく、例えば超格子層を１層
介在させるだけでもかなりの効果が期待される。 Although the present invention has been described in detail above, the present invention is not limited to this, and can be modified in various ways, for example, not only GaAs-AlGaAs but also InGaAs
The present invention can also be applied to other systems such as -InP system and AlGaInAs-GaAs system. Further, the superlattice structure is not limited to the five periods shown above, and a considerable effect can be expected even if, for example, only one superlattice layer is interposed.
発明の効果
本発明によれば、以上述べたように、量子井戸
型レーザ装置において、発振閾値電流を従来より
低減し、動作電流を小さくすることができ、きわ
めて有益である。Effects of the Invention According to the present invention, as described above, in a quantum well laser device, the oscillation threshold current can be lowered compared to the conventional one, and the operating current can be made smaller, which is extremely beneficial.
第１図は従来の量子井戸型レーザ装置の構造を
示す図、第２は本発明の量子井戸型レーザ装置の
構造を示す図、第３図は本発明の量子井戸型レー
ザ装置の構造の要部の組成（Alの組成比ｘ）を
示す図、第４図は本発明の量子井戸型レーザ装置
のバンドギヤツプによる説明図。
１……（GaAs）基板、２……（ｎ―GaAs）
バツフア層、３……（ｎ―AlGaAs）クラツド
層、４……グレーデツド・コンポジシヨン層、５
……活性層、６……グレーデツド・コンポジシヨ
ン層、７……（ｐ―AlGaAs）クラツド層、８…
…（ｐ―GaAs）コンタクト層。
FIG. 1 is a diagram showing the structure of a conventional quantum well laser device, FIG. 2 is a diagram showing the structure of the quantum well laser device of the present invention, and FIG. 3 is a diagram showing the main structure of the quantum well laser device of the present invention. FIG. 4 is an explanatory diagram of the bandgap of the quantum well laser device of the present invention. 1...(GaAs) substrate, 2...(n-GaAs)
Buffer layer, 3... (n-AlGaAs) cladding layer, 4... Graded composition layer, 5
...Active layer, 6...Graded composition layer, 7...(p-AlGaAs) clad layer, 8...
...(p-GaAs) contact layer.
Claims (1)
じ込め層（クラツド層）で活性層に隣接する部分
が傾斜型組成をもつ構造の半導体レーザにおい
て、 該傾斜型組成をもつ構造と基板との間に存在す
るエピタキシヤル層の一部にレーザ構造を構成す
る元素と同じ種類の元素の組み合せからなる超格
子構造のエピタキシヤル層を有することを特徴と
する量子井戸型レーザ装置。[Scope of Claims] 1. A semiconductor laser having a structure in which an active layer has a quantum well structure and a portion of an optical confinement layer (cladding layer) adjacent to the active layer has a graded composition, wherein: A quantum well laser device characterized in that a part of the epitaxial layer existing between the structure and the substrate has an epitaxial layer with a superlattice structure consisting of a combination of elements of the same type as the elements constituting the laser structure. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6021784A JPS60202981A (en) | 1984-03-28 | 1984-03-28 | Semiconductor laser device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6021784A JPS60202981A (en) | 1984-03-28 | 1984-03-28 | Semiconductor laser device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60202981A JPS60202981A (en) | 1985-10-14 |
| JPH0141269B2 true JPH0141269B2 (en) | 1989-09-04 |
Family
ID=13135772
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6021784A Granted JPS60202981A (en) | 1984-03-28 | 1984-03-28 | Semiconductor laser device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60202981A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2708744B2 (en) * | 1986-11-20 | 1998-02-04 | 三洋電機株式会社 | Semiconductor laser |
| JPH01236670A (en) * | 1988-03-17 | 1989-09-21 | Nec Corp | Semiconductor element |
| JPH02174178A (en) * | 1988-12-26 | 1990-07-05 | Sharp Corp | Semiconductor laser element |
-
1984
- 1984-03-28 JP JP6021784A patent/JPS60202981A/en active Granted
Non-Patent Citations (5)
| Title |
|---|
| APPL. PHY. LETT. 40 3 EXTREMELY LOW THRESHOLD ALGA AS GRADED-INDEX WAVEGUIDE SEPARATE-CONFINEMENT HETEROSTORUCTURE LASERS GROWN BY MOLECULAR BEAM EPITAXY=1982 * |
| APPLIED DHYSICS LETTERS=1981 * |
| APPLIED PHYSICS LETTERS=1981 * |
| APPLIED PHYSICS LETTERS=1984 * |
| COLLECTED PAPERS 2ND INTERNATIONAL SYMPOSIUM ON MOLECULAR BEAM EPITAXY AND RELATED CLEAN SURFACE TECHNIQUES=1982 * |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60202981A (en) | 1985-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6815731B2 (en) | Light emitting semiconductor device with GaInNAs active layers and GaAs spacer layers | |
| EP0232431B1 (en) | Semiconductor device | |
| JP2933051B2 (en) | Multiple quantum well structure optical semiconductor device and method of manufacturing the same | |
| JP4084506B2 (en) | Manufacturing method of semiconductor light emitting device | |
| JP3768790B2 (en) | Quantum dot structure and semiconductor device apparatus having the same | |
| JPH0141269B2 (en) | ||
| JPS60260181A (en) | Semiconductor luminescent device | |
| JPH0677592A (en) | Semiconductor laser element | |
| JPH0473610B2 (en) | ||
| JPH05160504A (en) | Semiconductor laser device | |
| JPH05267797A (en) | Light-emitting semiconductor diode | |
| US5302847A (en) | Semiconductor heterostructure having a capping layer preventing deleterious effects of As-P exchange | |
| JP4199835B2 (en) | Semiconductor light emitting device and method for manufacturing semiconductor light emitting device | |
| JP3828962B2 (en) | Semiconductor light emitting device | |
| JPH0541560A (en) | Semiconductor laser element | |
| JPH07120838B2 (en) | Semiconductor light emitting device | |
| JP2876543B2 (en) | Semiconductor device and manufacturing method thereof | |
| JP3279308B2 (en) | Nitride semiconductor light emitting device | |
| JPH1093194A (en) | Nitride semiconductor light-emitting element | |
| JP2000068585A (en) | Semiconductor laser | |
| JPH0467353B2 (en) | ||
| JP2967719B2 (en) | Semiconductor crystal growth method and semiconductor device | |
| JPH0632334B2 (en) | Semiconductor laser | |
| JP4068535B2 (en) | Semiconductor laser device, optical semiconductor device and manufacturing method thereof | |
| JPH01214083A (en) | Semiconductor laser device and its manufacture |