JP2525618B2 - Semiconductor laser - Google Patents
Semiconductor laserInfo
- Publication number
- JP2525618B2 JP2525618B2 JP21392787A JP21392787A JP2525618B2 JP 2525618 B2 JP2525618 B2 JP 2525618B2 JP 21392787 A JP21392787 A JP 21392787A JP 21392787 A JP21392787 A JP 21392787A JP 2525618 B2 JP2525618 B2 JP 2525618B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- semiconductor laser
- type
- semiconductor
- group compound
- 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 - Lifetime
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
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
- H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
- H01S5/2205—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers
- H01S5/2211—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers based on II-VI materials
-
- 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
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
- H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
- H01S5/223—Buried stripe structure
- H01S5/2231—Buried stripe structure with inner confining structure only between the active layer and the upper electrode
-
- 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
- H01S5/323—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
- H01S5/32308—Structure or shape of the active region; Materials used for the active region comprising PN junctions, e.g. hetero- or double- heterostructures in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser emitting light at a wavelength less than 900 nm
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、基本横モード発振をし、低閾値電流（以下
Ithと記す）において発振可能であり且つ高い信頼性を
有する半導体レーザの構造に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a fundamental transverse mode oscillation and a low threshold current (hereinafter
It is referred to as Ith) and is related to the structure of a semiconductor laser having high reliability.
従来の半導体レーザの構造は、膜厚方向にはAlxGa1-x
As/GaAsのダブヘテロ構造を用い、接合面平行方向には
活性層より小さな屈折率を有するAlxGa1-xAs系の半導体
層により電流狭窄及び光閉じ込め層を埋め込み形成する
ものであった。しかしこの従来技術では埋め込むAlxGa
1-xAs層の比抵抗が低いために、所望の発振領域以外に
電流の漏洩が起こりIthの低減には有効でない。従って
電流狭窄のためには発振領域のＰ−ｎ接合の順方向とは
逆方向の電圧がかかるようなＰ−ｎ接合を電流狭窄部に
おいて形成する必要があった。しかし、この場合活性層
直近に接合面ができ、且つキャリア濃度が高い場合には
Ｐ−ｎ接合の逆耐圧が弱いため活性層近傍で電流が漏れ
やすく、Ithの上昇及びそれによる高出力時のストライ
プ壁面の破壊など信頼性が低くなるという問題点を有し
ていた。このような問題点を解決するために、第34回応
用物理学会学術講演会予稿集、P715（1987年）講演番号
28P−ZH−８に、見られるような、リブ側面をII−VI族
化合物半導体によって埋め込む構造が考案された。この
従来技術ではII−VI族化合物半導体の１つであるZnSeを
用いている。ZnSeは107Ω・cm以上の高い比抵抗を有し
且つGaAs等のIII−Ｖ族化合物半導体より小さな屈折率
を持つ。従ってZnSe層は完全に電流の阻止層として機能
ししかも有効な光閉じ込め効果により基本横モードの発
振を制御可能でありIthが低く高出力動作まで安定して
発振可能であるというものであった。The structure of a conventional semiconductor laser is AlxGa 1- x in the thickness direction.
The current confinement and optical confinement layers were formed by embedding an Al / Ga1 - xAs semiconductor layer having a smaller refractive index than the active layer in the direction parallel to the junction plane, using the As / GaAs dub heterostructure. However, with this conventional technology, AlxGa embedded
Since the specific resistance of the 1- xAs layer is low, current leakage occurs outside the desired oscillation region, which is not effective in reducing Ith. Therefore, for current confinement, it was necessary to form a P-n junction in the current constriction portion in which a voltage in the direction opposite to the forward direction of the P-n junction in the oscillation region is applied. However, in this case, when a junction surface is formed in the immediate vicinity of the active layer and the reverse breakdown voltage of the P-n junction is weak when the carrier concentration is high, current easily leaks in the vicinity of the active layer, and Ith rises and the resulting high output power occurs. There was a problem that reliability was lowered, such as destruction of the stripe wall surface. In order to solve such a problem, the proceedings of the 34th JSAP Meeting, P715 (1987)
In 28P-ZH-8, a structure was devised as seen, in which the rib side surface was embedded with a II-VI group compound semiconductor. In this conventional technique, ZnSe, which is one of II-VI group compound semiconductors, is used. ZnSe has a high specific resistance of 10 7 Ω · cm or more and a smaller refractive index than III-V group compound semiconductors such as GaAs. Therefore, the ZnSe layer completely functions as a current blocking layer and can control the oscillation of the fundamental transverse mode by an effective optical confinement effect, and has a low Ith and can stably oscillate up to high output operation.
しかし前述の従来技術においても、GaAs及びGaAlAs等
のIII−Ｖ族化合物半導体は格子定数が5.653であり、Zn
Se層の格子定数が5.667であり、0.25％の格子定数不整
合が存在していた。従って、僅かではあるが残留応力が
残る、あるいは転移等の欠陥が発生し、長期寿命試験を
行なうと、駆動動作電流が徐々に上昇していく、あるい
は、数1000時間の間に破壊が生ずるといった信頼性に関
する問題点を有していた。However, even in the above-mentioned conventional technique, III-V group compound semiconductors such as GaAs and GaAlAs have a lattice constant of 5.653, and
The lattice constant of the Se layer was 5.667, and there was a lattice constant mismatch of 0.25%. Therefore, a slight residual stress remains, or a defect such as dislocation occurs, and when a long-term life test is performed, the driving operation current gradually increases, or breakdown occurs within several thousand hours. It had a problem with reliability.
そこで本発明はこのような問題点を解決するもので、
その目的とするところは、発振領域以外への電流の漏洩
を完全に遮断し、しかも有効な光閉じ込め効果により、
基本横モードの発振を制御可能であり、Ithが低く高出
力動作まで安定して発振可能であり、且つ、長寿命で、
高信頼性を有する半導体レーザを提供するところにあ
る。Therefore, the present invention solves such a problem,
The purpose is to completely shut off the leakage of current to areas other than the oscillation region, and by the effective optical confinement effect,
It can control the oscillation of the basic transverse mode, has a low Ith, can stably oscillate up to high output operation, and has a long life,
An object is to provide a semiconductor laser having high reliability.
III−Ｖ族化合物半導体より成る活性層及びクラッド
層で、構成されるダブルヘテロ接合型半導体レーザの前
記活性層直上のクラッド層の中間の深さまでエッチング
除去されたリブが形成され、該リブの両端はII−VI族化
合物より成る半導体層で埋め込まれている半導体レーザ
において、前記II−VI族化合物半導体層の少なくとも一
部の層平面中に、組成の異なるII−VI族化合物半導体層
が交互に複数回、順次積層して成る層を含んでいること
を特徴としている。Ribs are formed by etching to a depth midway between the clad layers directly above the active layer of the double heterojunction semiconductor laser composed of an active layer and a clad layer made of a III-V group compound semiconductor, and both ends of the ribs are formed. In a semiconductor laser embedded with a semiconductor layer made of a II-VI group compound, II-VI group compound semiconductor layers having different compositions are alternately arranged in at least a part of the plane of the II-VI group compound semiconductor layer. It is characterized in that it includes a layer formed by sequentially laminating a plurality of times.
本発明の上記の構成によれば、例えばZnSxSe1-x（０
≦ｘ≦１）とZnSySe1-y層（０≦ｙ≦1,x≠ｙ）を数Å〜
数10Åの周期で交互に複数回積層すると、積層界面に格
子不整合による歪みエネルギーが集中するため、界面準
位の形成が抑制される。その結果、II−VI族化合物半導
体の埋め込み層、例えばZnSeとIII−Ｖ族化合物半導体
の間に、このような積層構造をした層を挟むと、格子不
整合による転移等の発生あるいは残留応力の緩和といっ
た、現象がおこり、長期間半導体レーザを駆動しても劣
化が見られなくなる。According to the above configuration of the present invention, for example, ZnSxSe 1- x (0
≤ x ≤ 1) and ZnSySe 1- y layer (0 ≤ y ≤ 1, x ≠ y)
When the layers are laminated alternately a plurality of times with a period of several tens of Å, strain energy due to lattice mismatch is concentrated at the laminated interface, so that the formation of the interface state is suppressed. As a result, when a layer having such a laminated structure is sandwiched between a buried layer of a II-VI group compound semiconductor, for example, ZnSe and a III-V group compound semiconductor, dislocation or the like due to lattice mismatch or residual stress is generated. A phenomenon such as relaxation occurs, and deterioration is not seen even when the semiconductor laser is driven for a long time.
あるいは、コンタクト電極と例えばZnSeの間に、前述
の積層構造を挟むと、電極金属の熱膨張係数とZnSeの熱
膨張係数の違いによる残留応力を積層領域が緩和し、こ
れも半導体レーザの長期信頼性を向上させる。Alternatively, if the above-mentioned laminated structure is sandwiched between the contact electrode and ZnSe, for example, the residual stress due to the difference between the thermal expansion coefficient of the electrode metal and the thermal expansion coefficient of ZnSe is relaxed by the laminated region, which also contributes to the long-term reliability of the semiconductor laser. Improve sex.
（実施例１） 第１図は本発明の実施例における半導体レーザの主要
断面図である。（102）のｎ型GaAs単結晶基板上に（10
3）のｎ型GaAsバッファ層、（104）の、ｎ型AlGaAsクラ
ッド層、（105）のGaAsあるいはAlGaAs活性層と（106）
の逆メサ形状リブ型に形成された、Ｐ型AlGaAsクラッド
層、及び（111）のＰ型GaAsコンタクト層からなり、リ
ブ両端は（107）の厚さ50ÅのZnSxSe1-x（０≦ｘ≦１）
と（108）の厚さ50ÅのZnSySe1-y（０≦ｙ≦1,x≠ｙ）
を交互に順次50周期積層された、超格子薄膜（109）と
（110）のZnSe層によって埋め込まれている。具体的な
（107）と（108）の組み合わせは、例えば、ZnSe/ZnS
0.1Se0.0ZnSe/ZnS0.12Se0.88あるいはZnS0.05Se0.95/Zn
S0.2Se0.8などが選ばれる。コンタクト層上面のZnSe及
び超格子薄膜の部分はエッチング工程によって除去され
（111）のＰ型オーミック電極が形成される。（101）の
ｎ型オーミック電極が形成され（111）と（101）の間に
電流を順方向に流すことにより（105）の活性層に電荷
注入が起こり、キャリア再結合の発光が共振器端面間で
増幅されて、レーザ光が発振される。その場合（109）
の超格子薄膜及び（110）のZnSeは107Ω・cm以上の比抵
抗を有しており、注入電流はリブ直下以外を流れること
はほとんどない。レーザ発振はリブ直下の活性層のみで
起こり、むだな電流が流れないので、Ithは低く、15〜2
0mAが得られた。また、（109）の超格子構造は、GaAlAs
とZnSeの格子不整合を緩和し、残留応力あるいは転移等
の欠陥を生成しない。(Embodiment 1) FIG. 1 is a main sectional view of a semiconductor laser according to an embodiment of the present invention. (10) on an n-type GaAs single crystal substrate (10
(3) n-type GaAs buffer layer, (104) n-type AlGaAs cladding layer, (105) GaAs or AlGaAs active layer, and (106)
ZnSxSe 1- x (0 ≤ x ≤ 50 Å with a thickness of (107) at both ends consisting of a P-type AlGaAs clad layer and a (111) P-type GaAs contact layer formed in the reverse mesa shape rib type of 1)
And ZnSySe 1- y (0 ≦ y ≦ 1, x ≠ y) with a thickness of 50Å of (108)
Are embedded alternately by superlattice thin films (109) and (110), which are sequentially laminated for 50 cycles. The specific combination of (107) and (108) is, for example, ZnSe / ZnS.
0.1 Se 0.0 ZnSe / ZnS 0.12 Se 0.88 or ZnS 0.05 Se 0.95 / Zn
S 0.2 Se 0.8 etc. are selected. The ZnSe and superlattice thin film portions on the upper surface of the contact layer are removed by an etching process to form a (111) P-type ohmic electrode. An n-type ohmic electrode of (101) is formed, and a current is passed in the forward direction between (111) and (101) to cause charge injection into the active layer of (105), resulting in light emission of carrier recombination on the cavity end face. The laser light is oscillated by being amplified between them. In that case (109)
The superlattice thin film of (1) and ZnSe of (110) have a specific resistance of 10 7 Ω · cm or more, and the injected current hardly flows except under the rib. Laser oscillation occurs only in the active layer just below the rib, and no unnecessary current flows, so Ith is low and 15 to 2
0 mA was obtained. Also, the (109) superlattice structure is GaAlAs
It relaxes the lattice mismatch between ZnSe and ZnSe and does not generate defects such as residual stress or dislocation.
第７図は本発明の実施例における半導体レーザの長期
駆動試駆の結果を示す図である。光出力を5mWと一定と
し環境温度を70℃にして測定している。FIG. 7 is a diagram showing a result of a long-term drive test drive of the semiconductor laser in the example of the present invention. The light output is fixed at 5 mW and the ambient temperature is 70 ℃.
曲線（701）は本発明の実施例における半導体レーザ
の5mW出力にするための駆動電流の時間変化を示す。500
0時間までほとんど変化がない。A curve (701) shows the change over time of the drive current for making the semiconductor laser 5 mW output in the example of the present invention. 500
There is almost no change until 0 hours.
（702）は従来例の格子定数に不整合のある半導体層
で埋め込みを行なった半導体レーザの5mW出力にするた
めの、駆動電流の時間変化を示す。このように従来例で
は時間と共に駆動電流が上昇し劣化の速度が速い。(702) shows the time change of the drive current for making the output of the semiconductor laser embedded with a semiconductor layer having a mismatch in the lattice constant of the conventional example 5 mW. As described above, in the conventional example, the driving current increases with time, and the deterioration speed is high.
（実施例２） 第２図は、本発明の他の実施例における半導体レーザ
の主要断面図である。（202）のｎ型GaAs単結晶基板上
に（203）のｎ型GaAsバッファ層、（204）のｎ型AlGaAs
クラッド層、（205）のGaAsあるいはAlGaAs活性層と（2
06）の逆メサ形状リブ型に形成されたＰ型AlGaAsクラッ
ド層及び（211）のＰ型GaAsコンタクト層からなり、リ
ブ両端は（210）の、ZnSe層とその上には、（207）の厚
さ50Åの、ZnSxSe1-x（０≦ｘ≦１）と（208）の厚さ50
ÅのZnSySe1-y,x≠ｙ）を交互に順次50周期積層された
超格子薄膜（109）によって埋め込まれている。（210）
と（209）の埋め込み層は、（211）のコンタクト層の上
部のみエッチング工程によって除去されており、その後
（211）のＰ型オーミック電極、（201）のｎ型オーミッ
ク電極が形成される。Ｐ型オーミック電極金属、例え
ば、AuZn等の熱膨張係数は大きく、Ｐ電極化をヒートシ
ンクに、ダイボンドする際、大きな熱歪みを残したが、
第２図の、構造では、（209）の超格子構造が熱歪エネ
ルギーを吸収する。本実施例においても実施例１と同様
に低閾値、高信頼性の半導体レーザが製造できる。(Embodiment 2) FIG. 2 is a main sectional view of a semiconductor laser according to another embodiment of the present invention. (203) n-type GaAs buffer layer on (202) n-type GaAs single crystal substrate, (204) n-type AlGaAs
Clad layer, (205) GaAs or AlGaAs active layer and (2
It consists of a P-type AlGaAs cladding layer formed in the reverse mesa-shaped rib type of (06) and a P-type GaAs contact layer of (211), and both ends of the rib are (210), and ZnSe layer and (207) are formed on it. ZnSxSe 1- x (0 ≤ x ≤ 1) and (208) thickness 50 with a thickness of 50Å
Å ZnSySe 1- y, x ≠ y) are alternately embedded in a superlattice thin film (109) stacked for 50 cycles. (210)
The buried layers of (209) and (209) are removed by an etching process only on the upper part of the contact layer of (211), and then a P-type ohmic electrode of (211) and an n-type ohmic electrode of (201) are formed. P-type ohmic electrode metal, such as AuZn, has a large coefficient of thermal expansion, and a large thermal strain was left when die-bonding a P-electrode to a heat sink.
In the structure of FIG. 2, the superlattice structure of (209) absorbs thermal strain energy. Also in this embodiment, a semiconductor laser having a low threshold and high reliability can be manufactured as in the first embodiment.
（実施例３） 第３図は、本発明の他の実施例における半導体レーザ
の主要断面図である。（302）のｎ型単結晶基板上に（3
03）のｎ型GaAsバッファ層、（304）のｎ型AlGaAsクラ
ッド層、（305）のGaAsあるいはAlGaAs活性層と（306）
の逆メサ形状リブ型に、形成されたＰ型AlGaAsクラッド
層、及び（310）のＰ型GaAsコンタクト層からなり、リ
ブ両端は、（307）のZnSxSe1-x/ZnSySe1-y超格子薄膜と
（308）のZnSe層及び（309）のZnSxSe1-x/ZnSySe1-y超
格子薄膜を順次積層した層によって埋込まれている。
（307），（309）の超格子構造は、厚さ50ÅのZnSxSe1-
x（０≦ｘ≦１）と厚さ50Åの、ZnSySe1-y（０≦ｙ≦1,
x≠ｙ）を交互に順次50周期積層された超格子薄膜とな
っている。（307），（308），（309）の埋め込み層
は、（310）のコンタクト層の上部のみエッチング工程
によって除去されており、その後（311）のＰ型オーミ
ック電極、（301）のｎ型オーミック電極が形成され
る。実施例１及び実施例２の場合と同様に、格子不整合
による欠陥及び電極による、残留応用を緩和して、低閾
値、高信頼性の半導体レーザを製造できる。(Embodiment 3) FIG. 3 is a main sectional view of a semiconductor laser according to another embodiment of the present invention. On the (302) n-type single crystal substrate (3
(03) n-type GaAs buffer layer, (304) n-type AlGaAs cladding layer, (305) GaAs or AlGaAs active layer, and (306)
The reverse mesa-shaped rib type of P-type AlGaAs clad layer and (310) P-type GaAs contact layer formed on both ends of the rib are (307) ZnSxSe 1- x / ZnSySe 1- y superlattice thin film. And (308) ZnSe layer and (309) ZnSxSe 1- x / ZnSySe 1- y superlattice thin film are embedded in this order.
The superlattice structures of (307) and (309) are ZnSxSe 1- with a thickness of 50Å.
ZnSySe 1- y (0 ≦ y ≦ 1, x (0 ≦ x ≦ 1) and thickness 50Å)
It is a superlattice thin film in which x ≠ y) are alternately laminated for 50 cycles. The buried layers of (307), (308), and (309) are removed only by etching on the upper part of the contact layer of (310), and then the P-type ohmic electrode of (311) and the n-type ohmic electrode of (301). Electrodes are formed. As in the case of the first and second embodiments, it is possible to manufacture a low threshold and high reliability semiconductor laser by mitigating residual application due to defects due to lattice mismatch and electrodes.
次に第４図に基づいて本発明の実施例における半導体
レーザの製造工程を示す。Next, the manufacturing process of the semiconductor laser in the embodiment of the present invention will be described with reference to FIG.
（402）のｎ型GaAs単結晶基板上に、有機金属化合物
を原料とする熱分解化学気相成長法（以下MOCVD法と記
す）により（403）のｎ型GaAsバッファ層、（404）のｎ
型AlGaAsクラッド層、（405）のGaAsあるいはAlGaAs活
性層（406）のＰ型AlGaAsクラッド層、（407）のＰ型Ga
Asコンタクト層が順次積層される（第４図（ｂ））。次
に通常のフォト工程によって、ストライプ状のリブを、
形成する（第４図（ｃ））。次に（408）のZnSxSe1-x/Z
nSySe1-y超格子構造をMOCVD法により作成する。ジメチ
ルジンク（DMZn）とジメチルセレン（DMSe）の付加体及
び水素化セレン（H2Se）と水素化イオウ（H2S）を原料
とし、H2SeとH2Sの流量の制御によって組成の異なる50
Åの極薄膜を50周期交互に積層し、その後、（409）のZ
nSe層を連続して、埋め込み成長する（第４図
（ｄ））。次に再度、フォト工程により、リブの上の埋
め込み層をエッチングする（第４図（ｄ））。次に（41
0）のＰ型オーミック電極、（401）のｎ型オーミック電
極を形成する（第４図（ｆ））。The n-type GaAs buffer layer of (403) and the n-type of (404) are formed on the n-type GaAs single crystal substrate of (402) by thermal decomposition chemical vapor deposition (hereinafter referred to as MOCVD) using an organic metal compound as a raw material.
-Type AlGaAs cladding layer, (405) GaAs or AlGaAs active layer (406) P-type AlGaAs cladding layer, (407) P-type Ga
As contact layers are sequentially laminated (FIG. 4 (b)). Next, by a normal photo process, striped ribs,
It is formed (FIG. 4 (c)). Then (408) ZnSxSe 1- x / Z
nSySe 1- y superlattice structure is prepared by MOCVD method. Dimethyl zinc (DMZn) and dimethyl selenium (DMSe) adducts and hydrogenated selenium (H 2 Se) and hydrogenated sulfur (H 2 S) were used as raw materials, and the composition was controlled by controlling the flow rates of H 2 Se and H 2 S. Different 50
Å Ultra thin films are alternately laminated for 50 cycles, and then (409) Z
The nSe layer is continuously buried and grown (FIG. 4 (d)). Next, the buried layer on the rib is etched again by the photo process (FIG. 4 (d)). Then (41
A P-type ohmic electrode (0) and an n-type ohmic electrode (401) are formed (FIG. 4 (f)).
（実施例４） 第５図は本発明の他の実施例を示す半導体レーザの構
造図である。第５図（ｂ）は共振端面近傍の断面図を、
第５図（ｃ）は中央部での断面図を示す。第６図に第５
図の構造を達成する為の製造工程を示す。以下第６図を
用いて本発明を説明する。(Embodiment 4) FIG. 5 is a structural diagram of a semiconductor laser showing another embodiment of the present invention. FIG. 5 (b) is a sectional view in the vicinity of the resonance end face,
FIG. 5 (c) shows a sectional view at the central portion. No. 5 in FIG.
7 shows a manufacturing process for achieving the structure of the drawing. The present invention will be described below with reference to FIG.
ｎ型GaAs基板（602）にｎ型GaAsバッファ層（603）,n
型AlGaAsクラッド層（604）,GaAsあるいはAlGaAsの活性
層（605）,P型AlGaAsクラッド層（606）,P型GaAsコンタ
クト層、（607）より成るダブルヘテロ構造をMOCVD法を
用いて連続して形成する（第６図（ａ））。次いで通常
の、フォト工程によりエッチング用の、レジストマスク
（608）を、形成する、（第６図（ｂ））。レジストマ
スク（608）の形状は第６図（ｃ）の斜線で示す様な形
状である。続いてレジストマスクをエッチング用のマス
クとしてＰ型GaAsコンタクト層（607）及びＰ型AlGaAク
ラッド層（606）の、一部をエッチングし、その後にレ
ジストマスク（608）を除去する（第６図（ｄ））。次
に（609）のZnSxSe1-x/ZnSySe1-y、超格子構造（609）
を実施例１と同様の手順でMOCVD法により形成し、次に
連続してZnSe層（610）で埋め込み成長する（第６図
（ｅ））。続いてフォト工程及び埋め込み層のエッチン
グを行なう。エッチング後の素子の上面図を第６図
（ｇ）に示す。斜線部がII−VI族化合物半導体層であり
電流狭窄の効果を有する。中央部の、ストライプはエッ
チングにより、Ｐ型GaAsコンタクト層（607）が、露出
している部分である。以後Ｐ側電極（611）及びｎ側電
極（601）を形成して半導体レーザとなる。本実施例に
より形成される導波路は、II−VI族化合物半導体による
ためレーザ発振光の吸収は生じない。従って接合に平行
な方向に複素屈折率の実数部により形成される屈折率差
が生じ屈折率導波路となる。共振器端面近傍では上記屈
折率導波路の幅と電流注入幅を同程度として屈折率導波
機構としているので、安定な単一横モード発振が可能で
あり且つ、非点隔差の極めて小さなレーザ発振が得られ
る。また共振器中央部では導波路幅が十分に広く、利得
導波機構となり縦モードはマルチ化し、戻り光雑音の少
ない低雑音レーザが可能となる。更に（506）の超格子
薄膜が前記実施例と同様の働きをして、高い信頼性の半
導体レーザが得られる。An n-type GaAs buffer layer (603), n on an n-type GaAs substrate (602)
-Type AlGaAs clad layer (604), GaAs or AlGaAs active layer (605), P-type AlGaAs clad layer (606), P-type GaAs contact layer, and double heterostructure consisting of (607) are continuously formed by MOCVD method. It is formed (Fig. 6 (a)). Next, a resist mask (608) for etching is formed by a usual photo process (FIG. 6 (b)). The shape of the resist mask (608) is as shown by the diagonal lines in FIG. 6 (c). Then, using the resist mask as an etching mask, a part of the P-type GaAs contact layer (607) and the P-type AlGaA cladding layer (606) is etched, and then the resist mask (608) is removed (Fig. 6 ( d)). Then (609) ZnSxSe 1- x / ZnSySe 1- y, superlattice structure (609)
Are formed by the MOCVD method in the same procedure as in Example 1, and subsequently, a ZnSe layer (610) is continuously embedded and grown (FIG. 6 (e)). Subsequently, a photo process and etching of the buried layer are performed. A top view of the element after etching is shown in FIG. The shaded area is the II-VI group compound semiconductor layer and has the effect of current confinement. The stripe at the center is a portion where the P-type GaAs contact layer (607) is exposed by etching. After that, the P-side electrode (611) and the n-side electrode (601) are formed to form a semiconductor laser. Since the waveguide formed in this example is made of a II-VI group compound semiconductor, absorption of laser oscillation light does not occur. Therefore, a refractive index difference formed by the real part of the complex refractive index is generated in the direction parallel to the junction to form a refractive index waveguide. In the vicinity of the end face of the resonator, the width of the above-mentioned refractive index waveguide and the current injection width are set to be approximately the same to form a refractive index guiding mechanism, so that stable single transverse mode oscillation is possible and laser oscillation with an extremely small astigmatic difference is possible. Is obtained. In addition, the waveguide width is sufficiently wide in the central part of the resonator, which serves as a gain guiding mechanism, and the longitudinal modes are multi-modulated, and a low-noise laser with little return optical noise becomes possible. Further, the superlattice thin film of (506) functions in the same manner as in the above embodiment, and a highly reliable semiconductor laser can be obtained.
以上述べたように本発明によれば次のような効果を有
する。As described above, the present invention has the following effects.
（１） 埋め込み層に含まれる超格子薄膜は格子不整合
による転移等の欠陥や、残留応力を緩和するため、長時
間レーザ発振を駆動させても劣化することがほとんどな
い高信頼性の半導体レーザを得ることができる。(1) Since the superlattice thin film contained in the buried layer alleviates defects such as transition due to lattice mismatch and residual stress, it is a highly reliable semiconductor laser which hardly deteriorates even when laser oscillation is driven for a long time. Can be obtained.
（２） 埋め込みのII−VI族化合物半導体は極めて高い
比抵抗を有するため、発振領域以外への漏れ電流がほと
んどなく低いIthで発振可能であり従って半導体レーザ
の発熱が少なく、ヒートシンクへの実装等、半導体レー
ザの製造が、容易となる。同時に集積化レーザあるいは
光・電気集積素子（OEIC）等の基本構造として適してい
る。(2) Since the embedded II-VI group compound semiconductor has an extremely high specific resistance, there is almost no leakage current to regions other than the oscillation region and it is possible to oscillate at a low Ith, so the semiconductor laser generates less heat and is mounted on a heat sink, etc. Manufacturing of a semiconductor laser becomes easy. At the same time, it is suitable as a basic structure for integrated lasers or optical / electrical integrated devices (OEICs).
（３） 半導体レーザを構成する半導体層が全て、MOCV
D法により、製造可能であり、Znの拡散、あるいはイオ
ンの打ち込み等の生産性の悪い工程を必要としない。従
って広い面積にわたって均一な特性の半導体層を形成で
き、量産性にすぐれ、従ってコストの低い半導体レーザ
を供給できる。(3) All semiconductor layers composing the semiconductor laser are MOCV
It can be manufactured by the D method, and does not require a process with low productivity such as Zn diffusion or ion implantation. Therefore, it is possible to form a semiconductor layer having uniform characteristics over a wide area and to provide a semiconductor laser having excellent mass productivity and low cost.
（４） 埋め込みのII−VI族化合物半導体は発振領域を
構成するIII−Ｖ族化合物半導体と比べて小さな屈折率
を有するため複素屈折率実部による導波機構が可能であ
り、安定した基本横モードと低い非点収差を実現でき
る。(4) Since the embedded II-VI group compound semiconductor has a smaller refractive index than the III-V group compound semiconductor constituting the oscillation region, a waveguide mechanism with a complex refractive index real part is possible, and a stable basic lateral A mode and low astigmatism can be realized.
（５） 共振器中央部で幅の広いリブを形成すれば縦モ
ード多重発振となり戻り光雑音の極めて低い半導体レー
ザの製造が可能である。(5) If a wide rib is formed at the center of the resonator, longitudinal mode multiple oscillation occurs, and a semiconductor laser with extremely low return optical noise can be manufactured.
第１図は本発明の半導体レーザの一実施例を示す主要断
面図。 第２図は本発明の半導体レーザの一実施例を示す主要断
面図。 第３図は本発明の半導体レーザの一実施例を示す主要断
面図。 第４図（ａ）〜（ｆ）は本発明の半導体レーザの一実施
例を示す製造工程図。 第５図（ａ）〜（ｃ）は本発明の半導体レーザの一実施
例を示す構造図。（ａ）は上面図、（ｂ）はＡ−Ａ′に
おける断面図、（ｃ）はＢ−Ｂ′における断面図。 第６図（ａ）〜（ｇ）は本発明の半導体レーザの一実施
例を示す製造工程図。 第７図は本発明の半導体レーザの一実施例と従来例の駆
動電流と駆動時間の関係を示す図。 （101），（201），（301），（401），（501），（60
1）……ｎ型オーミック電極 （102），（202），（302），（402），（502），（60
2）……ｎ型GaAs基板 （103），（203），（303），（403），（503），（60
3）……ｎ型GaAsバッファ層 （104），（204），（304），（404），（504），（60
4）……ｎ型AlGaAsクラッド層 （105），（205），（305），（405），（505），（60
5）……活性層 （106），（206），（306），（406），（508），（60
6）……Ｐ型AlGaAsクラッド層 （111），（211），（310），（407），（509），（60
7）……Ｐ型GaAsコンタクト層 （112），（212），（311），（410），（510），（61
1）……Ｐ型オーミック電極 （701）……本発明の半導体レーザの特性曲線 （702）……従来の半導体レーザの特性曲線FIG. 1 is a main sectional view showing an embodiment of the semiconductor laser of the present invention. FIG. 2 is a main sectional view showing an embodiment of the semiconductor laser of the present invention. FIG. 3 is a main sectional view showing an embodiment of the semiconductor laser of the present invention. FIGS. 4A to 4F are manufacturing process diagrams showing an embodiment of the semiconductor laser of the present invention. 5 (a) to 5 (c) are structural views showing an embodiment of the semiconductor laser of the present invention. (A) is a top view, (b) is a sectional view taken along the line AA ', and (c) is a sectional view taken along the line BB'. 6 (a) to 6 (g) are manufacturing process diagrams showing an embodiment of the semiconductor laser of the present invention. FIG. 7 is a diagram showing the relationship between the driving current and the driving time of an example of the semiconductor laser of the present invention and a conventional example. (101), (201), (301), (401), (501), (60
1) N-type ohmic electrode (102), (202), (302), (402), (502), (60)
2) ... n-type GaAs substrate (103), (203), (303), (403), (503), (60
3) ... n-type GaAs buffer layer (104), (204), (304), (404), (504), (60
4) n-type AlGaAs cladding layer (105), (205), (305), (405), (505), (60)
5) ... Active layers (106), (206), (306), (406), (508), (60
6) P-type AlGaAs cladding layers (111), (211), (310), (407), (509), (60)
7) P-type GaAs contact layers (112), (212), (311), (410), (510), (61)
1) P-type ohmic electrode (701) ... characteristic curve of semiconductor laser of the present invention (702) ... characteristic curve of conventional semiconductor laser
Claims (1)
びクラッド層で構成される、ダブルヘテロ接合型半導体
レーザの前記活性層直上のクラッド層の中間の深さまで
エッチング除去されたリブが形成され、該リブの両端は
II−VI族化合物半導体より成る半導体層で埋め込まれて
いる半導体レーザにおいて、前記II−VI族化合物半導体
層中の少なくとも一部の層平面中に、組成の異なるII−
VI族化合物半導体層が交互に複数回、順次積層して成る
層を含んでいることを特徴とする半導体レーザ。1. A rib, which is composed of an active layer and a cladding layer made of a III-V compound semiconductor, is formed by etching to a depth intermediate to the cladding layer directly above the active layer of a double heterojunction semiconductor laser. , Both ends of the rib
In a semiconductor laser embedded with a semiconductor layer made of a II-VI group compound semiconductor, II-VI group compound semiconductor layers having different composition II-
A semiconductor laser comprising a layer in which a group VI compound semiconductor layer is alternately laminated a plurality of times in sequence.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21392787A JP2525618B2 (en) | 1987-08-27 | 1987-08-27 | Semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21392787A JP2525618B2 (en) | 1987-08-27 | 1987-08-27 | Semiconductor laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6457692A JPS6457692A (en) | 1989-03-03 |
| JP2525618B2 true JP2525618B2 (en) | 1996-08-21 |
Family
ID=16647348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21392787A Expired - Lifetime JP2525618B2 (en) | 1987-08-27 | 1987-08-27 | Semiconductor laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2525618B2 (en) |
-
1987
- 1987-08-27 JP JP21392787A patent/JP2525618B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6457692A (en) | 1989-03-03 |
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