JP3149879B2 - Semiconductor laser - Google Patents
Semiconductor laserInfo
- Publication number
- JP3149879B2 JP3149879B2 JP15884191A JP15884191A JP3149879B2 JP 3149879 B2 JP3149879 B2 JP 3149879B2 JP 15884191 A JP15884191 A JP 15884191A JP 15884191 A JP15884191 A JP 15884191A JP 3149879 B2 JP3149879 B2 JP 3149879B2
- Authority
- JP
- Japan
- Prior art keywords
- barrier
- layer
- semiconductor laser
- active layer
- cladding 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 - Fee Related
Links
Landscapes
- Semiconductor Lasers (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は活性層とｐ側クラッド層
との間に電子に対する障壁が設けられた半導体レーザに
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser having a barrier for electrons between an active layer and a p-side cladding layer.
【０００２】[0002]
【従来の技術】近年、ＡｌＧａＩｎＰを用いた可視光半
導体レーザが実用化されてきた。実用化されているＡｌ
ＧａＩｎＰ半導体レーザの発振波長は０．６７μｍ程度
である。これをＨｅ−Ｎｅガスレーザの０．６３３μｍ
まで短波長化する研究が盛んに進められている。短波長
化するには、半導体レーザの活性層のバンドギャップを
大きくすれば良い。しかし、この場合、活性層とクラッ
ド層のバンドギャップの差が小さくなり、キャリア、特
に電子の閉じ込めが悪くなり高温動作時の特性が悪化す
るという問題があった。そこで、活性層とｐ側クラッド
層との間に多重量子障壁を用いるという方法（エレクト
ロニクスレターズ１９８６年２２巻 １００８ページ、
１９９０年秋期応用物理学会、２７ｐ−Ｒ−２など）
や、Ａｌ組成の高いインナークラッド部を設ける方法
（特願平２−１５３４１２号）などが考えられている。2. Description of the Related Art In recent years, a visible light semiconductor laser using AlGaInP has been put to practical use. Practical Al
The oscillation wavelength of the GaInP semiconductor laser is about 0.67 μm. This was converted to a He—Ne gas laser of 0.633 μm.
Research on shortening the wavelength to that point is being actively pursued. To shorten the wavelength, the band gap of the active layer of the semiconductor laser may be increased. However, in this case, there is a problem that the difference in band gap between the active layer and the cladding layer becomes small, the confinement of carriers, especially electrons, becomes poor, and the characteristics at the time of high-temperature operation deteriorate. Therefore, a method of using a multiple quantum barrier between the active layer and the p-side cladding layer (Electronic Letters, 1986, Vol. 22, p. 1008,
(The 1990 Fall Society of Applied Physics, 27p-R-2, etc.)
And a method of providing an inner clad portion having a high Al composition (Japanese Patent Application No. 2-153412) has been considered.
【０００３】[0003]
【発明が解決しようとする課題】しかし、これらの方法
を用いても、十分に高い障壁を得ることができなかった
ために、キャリアの閉じ込めに関して、必ずしも満足の
ゆく効果を得ることができていない。本発明の課題は、
このような問題点を解消し、バンドギャップの高い量子
障壁を持つことができる半導体レーザを提供することに
ある。However, even with these methods, a sufficiently high barrier could not be obtained, so that satisfactory effects regarding the confinement of carriers could not always be obtained. The object of the present invention is to
An object of the present invention is to provide a semiconductor laser which can solve such a problem and has a quantum barrier having a high band gap.
【０００４】[0004]
【課題を解決するための手段】そのために本発明の半導
体レーザは、活性層とｐ側クラッド層との間に、引っ張
り応力が加わる材料による障壁が設けられ、その障壁が
多重障壁であって多重障壁の各障壁間に圧縮応力が加わ
る材料が用いられているものである。For this purpose, in the semiconductor laser of the present invention, a barrier made of a material to which a tensile stress is applied is provided between the active layer and the p-side cladding layer. A material to which a compressive stress is applied between the barriers is used.
【０００５】[0005]
【作用】障壁層に引っ張り応力が加わる材料を用いるこ
とにより、そのバンドギャップを高くとることができ
る。これにより、キャリア、特に電子が活性層からクラ
ッド層へ溢れ出ることをより効果的に防止できる。ただ
し、この層に与えられるひずみ量と厚みは転移が生じな
いような値にすることが望ましい。そのために、障壁は
多層構造となっていて、障壁層と障壁層の間のバンドギ
ャップの低い部分に反対側の歪みをいれて、全体の歪み
を緩和させている。この構造によれば、障壁層一層当た
りの歪み量を大きくしても、すなわち、実効的なバリア
高さを高くしても、全体の歪み量を小さくすることがで
き都合がよい。The band gap can be increased by using a material to which a tensile stress is applied to the barrier layer. This makes it possible to more effectively prevent carriers, particularly electrons, from overflowing from the active layer to the cladding layer. However, it is desirable that the amount of strain and the thickness given to this layer be values that do not cause transition. For this purpose, the barrier has a multilayer structure, in which a strain on the opposite side is applied to a portion having a low band gap between the barrier layers, thereby relaxing the entire strain. According to this structure, even if the amount of strain per barrier layer is increased, that is, even if the effective barrier height is increased, the entire amount of strain can be advantageously reduced.
【０００６】[0006]
【実施例】図１は本発明の一実施例である半導体レーザ
の活性層付近のエネルギバンドダイヤグラムであり、実
線１は伝導帯レベルを表している。この半導体レーザ
は、基板としてＧａＡｓ基板が用いられており、活性層
２としてアンドープ（Ａｌ0. 2 Ｇａ0.8 ）0.5 Ｉｎ0.5
Ｐ、ｎ型クラッド層３としてｎ−（Ａｌ0.7 Ｇａ0.3 ）
0.5 Ｉｎ0.5 Ｐ、ｐ型クラッド層４としてｐ−（Ａｌ
0.7 Ｇａ0.3 ）0.5 Ｉｎ0.5 Ｐがそれぞれ用いられてい
る。多重量子障壁５には、障壁層６としてｐ−（Ａｌ
0.7 Ｇａ0.3 ）0.6 Ｉｎ0.4 Ｐ、井戸層７としてｐ−
（Ａｌ0.7 Ｇａ0.3 ）0.4 Ｉｎ0.6 Ｐが用いられてい
る。FIG. 1 is an energy band diagram near an active layer of a semiconductor laser according to an embodiment of the present invention, and a solid line 1 indicates a conduction band level. This semiconductor laser has a GaAs substrate is used as the substrate, an undoped (Al 0. 2 Ga 0.8) as an active layer 2 0.5 an In 0.5
P, n- (Al 0.7 Ga 0.3 ) as the n-type cladding layer 3
0.5 In 0.5 P, p- (Al
0.7 Ga 0.3 ) 0.5 In 0.5 P is used. In the multiple quantum barrier 5, p- (Al
0.7 Ga 0.3 ) 0.6 In 0.4 P, p-
(Al 0.7 Ga 0.3 ) 0.4 In 0.6 P is used.
【０００７】この実施例によると、大きなバンドギャッ
プを持つ材料を用いて障壁層６が形成されているため、
活性層２からｐ側クラッド層４へのキャリアの溢れだし
を効果的に防止できる。しかし一方では、この材料はＧ
ａＡｓ基板との格子整合がとれておらず引っ張り応力が
加わっているため、たとえ各障壁層６の厚みが臨界膜厚
以下でも、何も対策を施さなければ転位が入る可能性が
ある。そこで、この実施例では、井戸層７に障壁層６と
反対向きの歪みが加わるような、すなわち圧縮応力が加
わるような材料が用いられており、障壁層６と井戸層７
の平均の格子定数が基板のそれに対して格子整合してい
る。したがって、転位は発生しない。また、従来のよう
に格子整合のとれる範囲内で障壁を高くするためにＡｌ
を多く含む材料を用いると、ｐ型不純物（通常は亜鉛）
のドーピングが難しいが、本実施例のように比較的Ａｌ
組成を低くしたまま障壁を高くするとドーピングが容易
となる。障壁層６と井戸層７の層厚の設計において留意
する点は、転位の発生防止のために各層の厚みをその層
の歪みに対する臨界膜厚以下することと、その範囲で電
子に対する障壁の効果が可能な限り大きくなるようにす
ることである。According to this embodiment, since the barrier layer 6 is formed using a material having a large band gap,
The overflow of carriers from the active layer 2 to the p-side cladding layer 4 can be effectively prevented. But on the other hand, this material is G
Since the lattice matching with the aAs substrate is not achieved and tensile stress is applied, even if the thickness of each barrier layer 6 is less than the critical film thickness, dislocation may occur if no measures are taken. Therefore, in this embodiment, a material is used in which strain is applied to the well layer 7 in a direction opposite to that of the barrier layer 6, that is, a compressive stress is applied.
Is lattice-matched to that of the substrate. Therefore, no dislocation occurs. Also, in order to increase the barrier within a range where lattice matching can be achieved as in the conventional case, Al
If a material containing a large amount of is used, p-type impurities (usually zinc)
Is difficult to dope, but relatively
Doping is facilitated by increasing the barrier while keeping the composition low. The points to keep in mind in designing the thickness of the barrier layer 6 and the well layer 7 are that the thickness of each layer is set to be equal to or less than the critical thickness with respect to the strain of the layer in order to prevent the occurrence of dislocation, and the effect of the barrier on electrons in that range. Is to be as large as possible.
【０００８】この半導体レーザの各層の形成は有機金属
気相合成法（ＯＭＶＰＥ法）を用いて行うことができ
る。その際に特に注意すべき点は、ｐドーパント（通常
は亜鉛）の拡散により多重量子障壁が壊れないように成
長条件を決めることである。発明者による実験では、亜
鉛とＩＩＩ族の原料供給比を１として７００℃でＯＭＶ
ＰＥ成長した場合、７０オングストローム程度の構造は
壊れずに残っており問題がなかった。Each layer of the semiconductor laser can be formed by using a metal organic chemical vapor synthesis (OMVPE) method. At this time, it should be particularly noted that the growth conditions are determined so that the multiple quantum barrier is not broken by the diffusion of the p dopant (usually, zinc). In an experiment by the inventor, OMV was performed at 700 ° C. with the feed ratio of zinc and group III being 1.
In the case of PE growth, a structure of about 70 Å remained unbroken and had no problem.
【０００９】なお、本実施例では、障壁層６としてｐ−
（Ａｌ0.7 Ｇａ0.3 ）0.6 Ｉｎ０．４ Ｐ、井戸層７と
してｐ−（Ａｌ０．７ Ｇａ0.3 ）0.4 Ｉｎ0.6 Ｐがそ
れぞれ用いられているが、一般的に示すと、障壁層６を
ｐ−（Ａｌa Ｇａ1-a ）b Ｉｎ1-b Ｐ、井戸層７をｐ−
（Ａｌc Ｇａ1-c ）d Ｉｎ1-d Ｐとしたとき、１≧ｂ＞
０．５≧ｄ≧０を満足させれば本発明の効果がある。な
お、添字ａおよびｃについては、通常は１≧ａ≧ｃ≧０
であるが、歪み量が十分に大きい場合は、ａ＜ｃとなっ
てもよい。また、各障壁層および各井戸層の組成比（添
字ａ，ｂ，ｃ，ｄ）は互いに異なっていてもよい。転位
が入らないようにする条件は、これらの定数にあわせて
実験で求めれば良い。In this embodiment, the barrier layer 6 is p-type.
(Al 0.7 Ga 0.3 ) 0.6 In 0.4 P and p- (Al 0.7 Ga 0.3 ) 0.4 In 0.6 P are used for the well layer 7, respectively. -(Al a Ga 1-a ) b In 1-b P, and the well layer 7 is p-
When (Al c Ga 1-c ) d In 1-d P, 1 ≧ b>
If 0.5 ≧ d ≧ 0 is satisfied, the effect of the present invention is obtained. Note that the subscripts a and c are usually 1 ≧ a ≧ c ≧ 0.
However, when the distortion amount is sufficiently large, a <c may be satisfied. Further, the composition ratios (subscripts a, b, c, d) of each barrier layer and each well layer may be different from each other. Conditions for preventing dislocations may be determined by experiments in accordance with these constants.
【００１０】上記の実施例では電子に対する障壁が多重
量子障壁であるが、必ずしも量子障壁である必要はな
い。量子効果のない多重障壁として、例えば、厚みが７
０オングストロームの（Ａｌ0.7 Ｇａ0.3 ）0.57Ｉｎ
0.43Ｐからなる障壁層を３層有し、これらの障壁層の間
に障壁層よりもバンドギャップの小さい厚みが５０オン
グストロームの（Ａｌ0.7 Ｇａ0.3 ）0.52Ｉｎ0.48Ｐか
らなる層を介在させたものなどが考えられる。In the above embodiment, the barrier against electrons is a multiple quantum barrier, but it need not be a quantum barrier. As a multiple barrier having no quantum effect, for example, a thickness of 7
0 Å (Al 0.7 Ga 0.3 ) 0.57 In
Three barrier layers made of 0.43 P, and a layer made of (Al 0.7 Ga 0.3 ) 0.52 In 0.48 P having a thickness of 50 angstroms and a smaller band gap than the barrier layers is interposed between these barrier layers. And so on.
【００１１】また、障壁は単層で形成してもよい。例え
ば、厚み１００オングストロームのＡｌ0.57Ｉｎ0.43Ｐ
の１層からなる障壁を活性層とｐ側クラッド層との間に
設けてもよい。The barrier may be formed as a single layer. For example, 100 Å thick Al 0.57 In 0.43 P
May be provided between the active layer and the p-side cladding layer.
【００１２】なお、上述した実施例は、すべてＡｌＧａ
ＩｎＰを活性層とする半導体レーザであるが、本発明の
半導体レーザはこれに限定されるものではない。例え
ば、ＧａＩｎＡｓを活性層とする半導体レーザにおいて
は、ＡｌＧａＩｎＡｓＰおよびＡｌＧａＩｎＡｓを用い
た障壁層とこれらの各層を隔てるバンドギャップの小さ
い層の組み合わせにより、多重障壁を作ることができ
る。It should be noted that all of the above-described embodiments are of AlGa
Although the semiconductor laser uses InP as an active layer, the semiconductor laser of the present invention is not limited to this. For example, in a semiconductor laser using GaInAs as an active layer, a multi-barrier can be formed by a combination of a barrier layer using AlGaInAsP and AlGaInAs and a layer having a small band gap separating these layers.
【００１３】[0013]
【発明の効果】以上説明したように、本発明の半導体レ
ーザによれば、障壁層に引っ張り応力が加わる材料を用
いることにより障壁を高め、キャリア、特に電子が活性
層からｐ側クラッド層へ溢れ出ることを防止できる。し
たがって、高い環境温度の中で動作させても特性の劣化
が生じにくい。As described above, according to the semiconductor laser of the present invention, the barrier is increased by using a material to which a tensile stress is applied to the barrier layer, and carriers, particularly electrons, overflow from the active layer to the p-side cladding layer. It can be prevented from leaving. Therefore, even if the device is operated at a high environmental temperature, the characteristics are hardly deteriorated.
【図１】本発明の一実施例である半導体レーザの活性層
付近のエネルギバンドダイヤグラムる。FIG. 1 is an energy band diagram near an active layer of a semiconductor laser according to an embodiment of the present invention.
１…伝導帯レベル ２…活性層 ３…ｎ型クラッド層 ４…ｐ型クラッド層 ５…多重量子障壁 ６…障壁層 ７…井戸層 DESCRIPTION OF SYMBOLS 1 ... Conduction band level 2 ... Active layer 3 ... N-type cladding layer 4 ... P-type cladding layer 5 ... Multiple quantum barrier 6 ... Barrier layer 7 ... Well layer
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01S 5/00 - 5/50 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. 7 , DB name) H01S 5/00-5/50
Claims (2)
対する障壁が設けられている半導体レーザにおいて、前
記障壁に引っ張り応力が加わる材料が用いられており、
前記障壁が多重障壁であってその多重障壁の各障壁間に
圧縮応力が加わる材料が用いられていることを特徴とす
る半導体レーザ。1. A semiconductor laser in which a barrier to electrons is provided between an active layer and a p-side cladding layer, wherein a material which applies a tensile stress to the barrier is used.
A semiconductor laser, wherein the barrier is a multi-barrier, and a material to which a compressive stress is applied between the barriers is used.
り、前記多重障壁の障壁層の材料がｐ−（ＡｌaＧ
ａ1-a）bＩｎ1-bＰ、障壁層間の材料がｐ−（ＡｌcＧａ
1-c）dＩｎ1-dＰ、ただし、１≧ｂ＞０．５≧ｄ≧０で
あることを特徴とする請求項１に記載の半導体レーザ。2. The material of the active layer is AlGaInP, and the material of the barrier layer of the multi-barrier is p- (Al a G
a 1-a ) b In 1-b P, and the material between the barrier layers is p- (Al c Ga
1-c ) d In 1-d P, where 1 ≧ b> 0.5 ≧ d ≧ 0, wherein the semiconductor laser according to claim 1.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15884191A JP3149879B2 (en) | 1991-02-01 | 1991-06-28 | Semiconductor laser |
| US07/892,805 US5274656A (en) | 1991-06-12 | 1992-06-08 | Semiconductor laser |
| EP92109831A EP0518320B1 (en) | 1991-06-12 | 1992-06-11 | Semiconductor laser |
| CA002071025A CA2071025C (en) | 1991-06-12 | 1992-06-11 | Semiconductor laser |
| DE69227403T DE69227403T2 (en) | 1991-06-12 | 1992-06-11 | Semiconductor laser |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1198091 | 1991-02-01 | ||
| JP3-11980 | 1991-02-01 | ||
| JP15884191A JP3149879B2 (en) | 1991-02-01 | 1991-06-28 | Semiconductor laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH053367A JPH053367A (en) | 1993-01-08 |
| JP3149879B2 true JP3149879B2 (en) | 2001-03-26 |
Family
ID=26347510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15884191A Expired - Fee Related JP3149879B2 (en) | 1991-02-01 | 1991-06-28 | Semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3149879B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200484295Y1 (en) * | 2015-09-01 | 2017-08-23 | 이대원 | Brassiere pad cover |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0606821A1 (en) * | 1993-01-11 | 1994-07-20 | International Business Machines Corporation | Modulated strain heterostructure light emitting devices |
| JP2536713B2 (en) * | 1993-02-08 | 1996-09-18 | 日本電気株式会社 | AlGaInP semiconductor laser device |
| US5600667A (en) * | 1993-04-05 | 1997-02-04 | Matsushita Electric Industrial Co., Ltd. | Semiconductor laser device |
| JPH07235733A (en) * | 1993-12-27 | 1995-09-05 | Sanyo Electric Co Ltd | Semiconductor laser element |
-
1991
- 1991-06-28 JP JP15884191A patent/JP3149879B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200484295Y1 (en) * | 2015-09-01 | 2017-08-23 | 이대원 | Brassiere pad cover |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH053367A (en) | 1993-01-08 |
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