JPH07312459A - Optical semiconductor element - Google Patents
Optical semiconductor elementInfo
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- JPH07312459A JPH07312459A JP12573294A JP12573294A JPH07312459A JP H07312459 A JPH07312459 A JP H07312459A JP 12573294 A JP12573294 A JP 12573294A JP 12573294 A JP12573294 A JP 12573294A JP H07312459 A JPH07312459 A JP H07312459A
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- Prior art keywords
- film
- optical
- layer
- semiconductor
- semiconductor element
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Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、光通信システムなどに
用いられる光信号を直接増幅する為の高帯域半導体光増
幅器等である、端面に、保護性能を有しかつ無反射コー
ティングの光学膜などを持つ光半導体素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high bandwidth semiconductor optical amplifier or the like for directly amplifying an optical signal used in an optical communication system or the like, which has an end face having a protective performance and an antireflection coating optical film. The present invention relates to an optical semiconductor device having
【0002】[0002]
【従来の技術】従来、半導体光増幅器は、図7に示す様
に、基板100上形成された上下クラッド層105、1
06に挟まれた活性層102を含む半導体レーザ構造1
01を有し、そのへき開端面に反射防止(AR)コーテ
ィング103a、103bを施すことによって、電流1
04の注入で高い内部ゲインを与えた場合にもレーザ発
振が抑えられる様な構造を有している。2. Description of the Related Art Conventionally, as shown in FIG. 7, a semiconductor optical amplifier has an upper and lower cladding layers 105, 1 formed on a substrate 100.
Semiconductor laser structure 1 including an active layer 102 sandwiched between 06
01, and by applying antireflection (AR) coatings 103a and 103b to the cleaved end face,
The structure is such that laser oscillation can be suppressed even when a high internal gain is given by injection of 04.
【0003】このARコーティングの良否は半導体光増
幅器の性能を左右し、入力波長スペクトルに対するゲイ
ンの増減(ゲインリップル)を抑えるにはARコーティ
ングの反射率を低く抑える必要がある。ゲインリップル
を2dBとした場合の単一通過ゲインGとARコーティ
ングの反射率Rとの条件は GR<または≒0.1 で与えられる。例えば、ゲイン20dBとした場合の反
射率はR<または≒0.1%となる。The quality of the AR coating determines the performance of the semiconductor optical amplifier, and it is necessary to keep the reflectance of the AR coating low in order to suppress the gain increase / decrease (gain ripple) with respect to the input wavelength spectrum. The condition of the single pass gain G and the reflectance R of the AR coating when the gain ripple is 2 dB is given by GR <or ≈0.1. For example, when the gain is 20 dB, the reflectance is R <or ≈0.1%.
【0004】こうした反射率Rを低減し波長スペクトル
に対するゲインリップルを解消した光増幅器は、多波長
多重化信号の光増幅に有用であり、進行波型光増幅器と
称される。An optical amplifier which reduces the reflectance R and eliminates the gain ripple for the wavelength spectrum is useful for optical amplification of a multi-wavelength multiplexed signal and is called a traveling wave type optical amplifier.
【0005】ARコーティング103a、103bの形
成手段としては、通常、へき開端面に所望の屈折率を有
する誘電体膜をλ/4(λは光波長)の厚さで堆積して
いる。ここでの所望の屈折率は、用いる半導体材料、導
波路構造で異なるが、GaAs/AlGaAs系のレー
ザにおいては、最適屈折率の値はおおよそn≒1.85
である。As a means for forming the AR coatings 103a and 103b, a dielectric film having a desired refractive index is usually deposited on the cleaved end face in a thickness of λ / 4 (λ is a light wavelength). The desired refractive index here differs depending on the semiconductor material used and the waveguide structure, but in the laser of GaAs / AlGaAs system, the optimum refractive index value is approximately n≈1.85.
Is.
【0006】また、上記GaAs/AlGaAs系の半
導体レーザ素子は、その端面の界面準位の存在により、
レーザ光吸収による温度上昇が生じ、雰囲気の酸素によ
って端面の酸化が促進され、素子の破壊が生じる。その
ため、素子端面には保護性能を有する膜を積層する必要
があるが、一方、GaAsと保護膜材料との熱膨張係数
が違いすぎると、熱応力により半導体素子の活性層内に
転移が発生し、素子が劣化することもある。Further, the GaAs / AlGaAs semiconductor laser device has an interface level at its end face,
The temperature rises due to the absorption of the laser light, and the oxygen in the atmosphere promotes the oxidation of the end faces, resulting in the destruction of the device. Therefore, it is necessary to stack a film having a protective property on the end face of the device. On the other hand, if the thermal expansion coefficients of GaAs and the protective film material are too different, thermal stress causes dislocation in the active layer of the semiconductor device. However, the element may deteriorate.
【0007】従来、上記保護膜としては、GaAsと熱
膨張係数がほぼ等しいAl2O3が使用されていた。ま
た、AlNやSi3N4も、酸化防止の保護膜として光
ディスク等に使用されている。更に、高屈折率の材料と
低屈折率の材料との混合により屈折率を制御して、反射
防止コーティングを開示した例もある。その他、2層膜
以上の多層膜構成にした例もある。Conventionally, Al 2 O 3 having a thermal expansion coefficient substantially equal to that of GaAs has been used as the protective film. Further, AlN and Si 3 N 4 are also used in optical discs and the like as a protective film for preventing oxidation. Further, there is an example in which an antireflection coating is disclosed by controlling the refractive index by mixing a material having a high refractive index and a material having a low refractive index. In addition, there is also an example in which a multi-layer structure including two or more layers is used.
【0008】[0008]
【発明が解決しようとしている課題】しかし、上記従来
例のAl2O3単層では、Al2O3の屈折率が小さい
(1.63〜1.66)ので、Rを0.1%以下にする
ことは無理である。また、AlN、Si3N4は屈折率
が大きい(2.0〜2.2)ので、それぞれの単層で
は、Rを0.1%以下にはできない。更に、GaAsと
の熱膨張係数の違いにより、半導体レーザ活性層内に格
子欠陥を生じさせる問題がある。However, in the Al 2 O 3 single layer of the above conventional example, the refractive index of Al 2 O 3 is small (1.63 to 1.66), so that R is 0.1% or less. It is impossible to do this. Further, since AlN and Si 3 N 4 have large refractive indexes (2.0 to 2.2), R cannot be 0.1% or less in each single layer. Further, there is a problem that a lattice defect occurs in the semiconductor laser active layer due to the difference in thermal expansion coefficient from GaAs.
【0009】高屈折率の材料と低屈折率の材料との混合
層の場合は、その組み合わせにおいて酸化物を使用する
と、遊離酸素による端面への影響があり、非酸化物を使
用すると、保護性能の他にGaAsとの熱膨張係数の問
題を解決しなければならない。更に、Rを0.1%以下
にするには、GaAs/AlGaAs系のレーザでは、
最適屈折率の値が約1.85であるため、混合層の屈折
率nを1.80≦n≦1.90の範囲にしなければなら
ない。In the case of a mixed layer of a material having a high refractive index and a material having a low refractive index, when an oxide is used in the combination, the end surface is affected by free oxygen, and when a non-oxide is used, the protective performance is improved. Besides, the problem of thermal expansion coefficient with GaAs must be solved. Furthermore, in order to reduce R to 0.1% or less, in a GaAs / AlGaAs laser,
Since the value of the optimum refractive index is about 1.85, the refractive index n of the mixed layer must be within the range of 1.80 ≦ n ≦ 1.90.
【0010】多層膜構成の場合は、各層に用いる材料の
屈折率、保護性能、熱膨張係数等を考慮する必要があ
る。例えば、素子端面側の第1の薄膜にAl2O3、第
2の薄膜にAlNあるいはSi3N4を用いた2層膜の
場合、膜厚制御によりRを低く設計でき、また比較的耐
久性能も良いが、それでもまだ充分でない。これは、素
子に接しているAl2O3からの遊離酸素の影響が皆無
でないこと、またAl2O3はGaAsとの密着性に問
題があり、多層にして膜厚が厚くなると、レーザ素子端
面から剥離が生じること等の理由による。In the case of a multilayer film structure, it is necessary to consider the refractive index, protective performance, thermal expansion coefficient, etc. of the material used for each layer. For example, in the case of a two-layer film using Al 2 O 3 for the first thin film and AlN or Si 3 N 4 for the second thin film on the device end face side, R can be designed to be low by controlling the film thickness, and the durability is comparatively low. Good performance, but still not enough. This is the influence of free oxygen from the Al 2 O 3 in contact with the element is not nil, and Al 2 O 3 has a problem in adhesion to the GaAs, the thickness in the multilayer is increased, the laser device This is due to reasons such as peeling from the end faces.
【0011】よって、本発明の目的は、Al2O3、A
lN、Si3N4などを用いながら上記課題を解決し
た、端面に光学膜を持つ光半導体素子を提供することに
ある。Therefore, the object of the present invention is to provide Al 2 O 3 , A
An object of the present invention is to provide an optical semiconductor element having an optical film on the end face, which solves the above-mentioned problems while using 1N, Si 3 N 4, etc.
【0012】[0012]
【課題を解決するための手段】本発明においては、Ga
As/AlGaAs系の半導体レーザ素子の端面保護膜
兼光学膜などとして、高耐久性と0.1%以下の反射率
を実現した素子などを提供する。In the present invention, Ga
Provided is an element that realizes high durability and a reflectance of 0.1% or less as an end face protective film / optical film of an As / AlGaAs semiconductor laser device.
【0013】即ち、本発明の半導体光増幅器では、入出
力端面に反射防止の光学膜を施した半導体レーザ構造を
有する半導体光増幅器において、該光学膜は、2層の誘
電体薄膜の組み合わせからなり、該半導体レーザ構造端
面側の第1の薄膜は、AlN、Si3N4から選ばれる少
なくとも1種の材料と、Al2O3の材料との膜からな
り、該AlN、Si3N4から選ばれる少なくとも1種の
材料の組成濃度は、半導体レーザ構造端面側が大きく、
膜厚方向に徐々に組成濃度が減少し、かつAl2O3の組
成濃度は、半導体レーザ構造端面側が小さく、膜厚方向
に徐々に組成濃度が増加し、平均屈折率が1.90より
大きい傾斜組成膜であり、第2の薄膜はAl2O3の材料
からなることを特徴とする。That is, in the semiconductor optical amplifier of the present invention, in the semiconductor optical amplifier having a semiconductor laser structure in which an antireflection optical film is applied to the input / output end face, the optical film is composed of a combination of two dielectric thin films. a first thin film of the semiconductor laser structure end face side, AlN, and at least one material selected from Si 3 N 4, made from the membrane of a material of the Al 2 O 3, the AlN, the Si 3 N 4 The composition concentration of at least one material selected is large on the end face side of the semiconductor laser structure,
The composition concentration gradually decreases in the film thickness direction, and the composition concentration of Al 2 O 3 is small on the end face side of the semiconductor laser structure, the composition concentration gradually increases in the film thickness direction, and the average refractive index is larger than 1.90. It is a graded composition film, and the second thin film is made of a material of Al 2 O 3 .
【0014】また、本発明の光半導体素子では、端面に
光学膜を施した光半導体素子において、該光学膜は、2
層の誘電体薄膜の組み合わせからなり、該光半導体素子
端面側の第1の薄膜は、窒化アルミニウム、窒化シリコ
ンから選ばれる少なくとも1種の材料と、酸化アルミニ
ウムの材料との膜からなり、該窒化アルミニウム、窒化
シリコンから選ばれる少なくとも1種の材料の組成濃度
は、光半導体素子端面側が大きく、膜厚方向に徐々に組
成濃度が減少し、かつ酸化アルミニウムの組成濃度は、
光半導体素子端面側が小さく、膜厚方向に徐々に組成濃
度が増加し、第2の薄膜は酸化アルミニウムの材料から
なることを特徴とする。Further, in the optical semiconductor element of the present invention, in the optical semiconductor element having an end face provided with an optical film, the optical film is 2
The first thin film on the end face side of the optical semiconductor element is made of a combination of at least one material selected from aluminum nitride and silicon nitride and a material of aluminum oxide. The composition concentration of at least one material selected from aluminum and silicon nitride is large on the end face side of the optical semiconductor element, gradually decreases in the film thickness direction, and the composition concentration of aluminum oxide is
The optical semiconductor element is characterized in that the end face side is small, the composition concentration gradually increases in the film thickness direction, and the second thin film is made of a material of aluminum oxide.
【0015】[0015]
【実施例1】まず、本発明の光学膜材料を用いた半導体
光増幅器の実施例を斜視図である図1に示す。基本構造
となる半導体レーザ構造は、リッジ型レーザ1が用いら
れていて、へき開面は、傾斜組成膜2を含む2層の光学
膜材料2、3から成る。次に、半導体レーザデバイスの
構成と作製方法について説明する。Example 1 First, FIG. 1 is a perspective view showing an example of a semiconductor optical amplifier using the optical film material of the present invention. A ridge type laser 1 is used as a semiconductor laser structure as a basic structure, and a cleavage plane is composed of two layers of optical film materials 2 and 3 including a gradient composition film 2. Next, the structure and manufacturing method of the semiconductor laser device will be described.
【0016】図2において、21はn型GaAs基板、
22はn型AlxGa1−xAsクラッド層(Al混晶
比x=0.3)、23はGaAs活性層、24はp型A
lxGa1−xAs(x=0.3)クラッド層、25は
p+キャップ層である。これらのエピタキシャル膜は分
子線エピタキシャル(MBE)法或いは有機金属熱分解
(MO−CVD)法などによって堆積、形成される。こ
の後、フォトリソグラフィによるリッジ部のパターニン
グ後、反応性イオンビームエッチング(RIBE)法に
よって、幅2〜3μm、深さ0.3〜0.4μmのリッ
ジ部を形成する。更に、SiNx膜26を堆積した後、
キャップ部25からの電流注入を可能とする窓開けを行
い、上面及び下面にAu膜を堆積しアロイ化を行ってオ
ーミック電極27、28の形成を行う。In FIG. 2, 21 is an n-type GaAs substrate,
22 is an n-type Al x Ga 1-x As clad layer (Al mixed crystal ratio x = 0.3), 23 is a GaAs active layer, and 24 is p-type A
1 x Ga 1-x As (x = 0.3) cladding layer, and 25 is a p + cap layer. These epitaxial films are deposited and formed by a molecular beam epitaxy (MBE) method or a metal organic thermal decomposition (MO-CVD) method. Then, after patterning the ridge portion by photolithography, a ridge portion having a width of 2 to 3 μm and a depth of 0.3 to 0.4 μm is formed by a reactive ion beam etching (RIBE) method. Further, after depositing the SiN x film 26,
A window is opened to allow current injection from the cap portion 25, an Au film is deposited on the upper and lower surfaces and alloyed to form ohmic electrodes 27 and 28.
【0017】上記のプロセスが終了したレーザウエハ
は、バー状あるいはチップ状にへき開され、へき開端面
に上記の光学膜材料構成によるコーティング処理が行わ
れる。The laser wafer which has undergone the above process is cleaved into a bar shape or a chip shape, and the cleaved end face is subjected to coating treatment with the above optical film material constitution.
【0018】コーティングの層構成を示す図3におい
て、2、3は、本実施例の傾斜組成膜2を含む2層の光
学膜である。半導体レーザ端面側の傾斜組成膜2を構成
するAlN、Si3N4から選ばれる少くとも1種の材料
は、非酸化物であり、環境雰囲気からの酸素や水分から
半導体端面を保護する性能が高い保護膜となる。また、
同じく傾斜組成膜2を構成するAl2O3は、熱膨張係数
(5.60×10-6deg-1)がGaAsの値(5.7
3×10-6deg-1)に近く、熱応力に起因する半導体
素子の劣化の生じることがない材料である。In FIG. 3 showing the layer structure of the coating, reference numerals 2 and 3 denote two-layer optical films including the gradient composition film 2 of this embodiment. At least one material selected from AlN and Si 3 N 4 forming the gradient composition film 2 on the semiconductor laser end face side is a non-oxide, and has a property of protecting the semiconductor end face from oxygen and moisture from the ambient atmosphere. It becomes a high protective film. Also,
Similarly, Al 2 O 3 forming the gradient composition film 2 has a coefficient of thermal expansion (5.60 × 10 −6 deg −1 ) of GaAs (5.7).
It is a material close to 3 × 10 −6 deg −1 ) and does not cause deterioration of the semiconductor element due to thermal stress.
【0019】この両方の材料を混合、しかも傾斜組成と
することにより、傾斜組成膜2の平均屈折率nを1.9
0より大きくし、かつ、第2層膜3を低屈折率のAl2
O3とするこにとより、端面反射率を0.1%以下にで
きる。更に、Al2O3からの遊離酸素の端面への影響
を、端面側の組成濃度について、AlN、Si3N4から
選ばれる少くとも1種の材料の組成濃度を大きくAl2
O3の組成濃度を小さくすることにより、防止でき、か
つ、傾斜組成膜2の平均熱膨張係数をGaAsに近い値
(5〜7×10-6deg-1)にすることができる。ま
た、素子端面との密着性も、端面側のAl2O3濃度が小
さいので問題がない。The average refractive index n of the graded composition film 2 is 1.9 by mixing both materials and making them a graded composition.
And the second layer film 3 is made of Al 2 having a low refractive index.
By using O 3 , the end face reflectance can be set to 0.1% or less. Further, Al 2 O the impact on the end face of the free oxygen from 3, the composition concentration of the end face, AlN, Si 3 at least selected from N 4 increases the composition concentration of one material Al 2
By reducing the composition concentration of O 3, the composition can be prevented and the average thermal expansion coefficient of the graded composition film 2 can be set to a value close to GaAs (5 to 7 × 10 −6 deg −1 ). Further, there is no problem with the adhesion to the device end face because the Al 2 O 3 concentration on the end face side is low.
【0020】各材料の半導体レーザ素子端面への傾斜組
成膜2の積層は、スパッタ法や電子ビーム蒸着法等の通
常の真空製膜法が適用できる。AlNの場合は、AlN
をターゲットとして、スパッタガスをArあるいはAr
+N 2の混合ガス等を用いたスパッタ法や、AlNを蒸
発源とした電子ビーム蒸着法で製膜できる。Si3N4
の場合も同様に、Si3N4をターゲットとして、Ar
あるいはAr+N2をスパッタガスに用いたスパッタ
法、Si3N4を蒸発源とした電子ビーム蒸着法て製膜で
きる。Inclined set of each material to the end face of the semiconductor laser device
The stacking of the film formation 2 is performed by a sputtering method, an electron beam evaporation method, or the like.
The usual vacuum film forming method can be applied. In the case of AlN, AlN
The target is Ar and the sputtering gas is Ar or Ar.
+ N TwoOf AlN and the sputtering method using mixed gas of
The film can be formed by the electron beam evaporation method used as the source. SiThreeNFour
Similarly, in the case ofThreeNFourTarget, Ar
Or Ar + NTwoSputtering using as a sputtering gas
Law, Si3NFourElectron beam evaporation method using
Wear.
【0021】AlNとSi3N4の混合物は、上記のそ
れぞれのターゲットを用いた同時スパッタ法や、あらか
じめ、AlNとSi3N4を焼結して形成したターゲッ
トを用いる方法、AlNとSi3N4の混合物を蒸発源
とした電子ビーム蒸着法で製膜できる。[0021] Mixtures of AlN and Si 3 N 4 is the simultaneous sputtering and using each target of the advance, a method using a target formed by sintering AlN and Si 3 N 4, AlN and Si 3 The film can be formed by an electron beam evaporation method using a mixture of N 4 as an evaporation source.
【0022】Al2O3は、Al2O3をターゲットと
して、ArあるいはAr+O2をスパッタガスに用いた
り、Alをターゲットとして、Ar+O2をスパッタガ
スとして用いたスパッタ法や、Al2O3を用いた電子
ビーム蒸着法が簡便である。As Al 2 O 3 , a sputtering method using Al 2 O 3 as a target and Ar or Ar + O 2 as a sputtering gas, an Al target as Ar + O 2 as a sputtering gas, or Al 2 O 3 is used. The electron beam evaporation method used is simple.
【0023】図4は、本発明の実施例の傾斜組成膜2の
スパッタ法による製膜法及び製膜装置を簡略的に示す図
である。61は、AlN、Si3N4から選ばれる少な
くとも1種の材料から成るターゲット、62はAl2O
3から成るターゲット、63は端面に傾斜組成膜2を含
む反射防止膜を積層する半導体素子、64は半導体素子
63のホルダー基板、65は半導体素子63の移動方
向、66は隔壁板である。FIG. 4 is a diagram schematically showing a film forming method and a film forming apparatus for the gradient composition film 2 by the sputtering method according to the embodiment of the present invention. 61 is a target made of at least one material selected from AlN and Si 3 N 4 , and 62 is Al 2 O.
3 is a target, 63 is a semiconductor element in which an antireflection film including the gradient composition film 2 is laminated on the end face, 64 is a holder substrate of the semiconductor element 63, 65 is a moving direction of the semiconductor element 63, and 66 is a partition plate.
【0024】2つのターゲットを同時にスパッタできる
2元同時スパッタ装置を用いて、半導体素子63を移動
或は回転可能な状態で、ターゲット61に近い方から、
矢印65に示す方向に移動して製膜する。製膜は、移動
に従って、ターゲット61の材料組成が徐々に減少し、
ターゲット62の材料(Al2O3)組成が徐々に増加
する。Using a binary simultaneous sputtering apparatus capable of simultaneously sputtering two targets, the semiconductor element 63 can be moved or rotated, and the semiconductor element 63 can be moved from the side closer to the target 61.
The film is formed by moving in the direction indicated by arrow 65. In the film formation, the material composition of the target 61 gradually decreases as it moves,
The material (Al 2 O 3 ) composition of the target 62 gradually increases.
【0025】傾斜組成膜2の各々の材料の組成は、各タ
ーゲット61、62に投入する電力や、スパッタガス
圧、スパッタガス種、基板間距離等で決まる各々の製膜
速度と、半導体素子63の移動速度、隔壁板66の高
さ、各ターゲット61、62の配置等で制御可能であ
る。そして、傾斜組成膜2の平均屈折率nをあらかじめ
測定しておいて、nが1.90より大きいとき、傾斜組
成膜2に続く第2層目3をAl2O3で製膜すると、反射
率Rを0.1%以下にすることが可能となる。The composition of each material of the gradient composition film 2 is determined by the power supplied to the targets 61 and 62, the sputtering gas pressure, the sputtering gas species, the distance between the substrates, and the like, and the semiconductor element 63. Can be controlled by the moving speed, the height of the partition plate 66, the arrangement of the targets 61 and 62, and the like. Then, the average refractive index n of the gradient composition film 2 is measured in advance, and when n is larger than 1.90, when the second layer 3 following the gradient composition film 2 is formed of Al 2 O 3 , it is reflected. The rate R can be made 0.1% or less.
【0026】例えば、第1層目の傾斜組成膜2の平均屈
折率nが2.2、第2層目3をAl2O3(屈折率1.6
3〜1.66)とした場合、Rが0.1%以下を満たす
ためには、第1層目の膜厚は480〜620Å、第2層
目の膜厚は750〜950Åの範囲が望ましい。第1層
目のnが2.0のときは、第1層目の膜厚は600〜8
00Å、第2層目の膜厚は500〜800Åの範囲が望
ましい。第1層目のnが1.95のときは、第1層目の
膜厚は650〜950Å、第2層目の膜厚は250〜7
50Åの範囲が望ましい。第1層目のnが1.91のと
きは、第1層目の膜厚は680〜1100Å、第2層目
の膜厚は100〜620Åの範囲が望ましい。For example, the average refractive index n of the gradient composition film 2 of the first layer is 2.2, and the average refractive index n of the second layer 3 is Al 2 O 3 (refractive index 1.6.
3 to 1.66), in order to satisfy R of 0.1% or less, the thickness of the first layer is preferably 480 to 620Å and the thickness of the second layer is preferably 750 to 950Å. . When n of the first layer is 2.0, the thickness of the first layer is 600 to 8
The film thickness of 00Å and the second layer is preferably in the range of 500 to 800Å. When n of the first layer is 1.95, the thickness of the first layer is 650 to 950Å and the thickness of the second layer is 250 to 7
A range of 50Å is desirable. When n of the first layer is 1.91, the thickness of the first layer is preferably 680 to 1100Å, and the thickness of the second layer is preferably 100 to 620Å.
【0027】こうして、半導体レーザ端面に傾斜組成膜
2を形成した半導体光増幅器は、ゲインリップルの測定
により、反射率0.1%以下を実現できる。図1に示す
ように、半導体光増幅器を、閾値電流より少し小さい定
電流注入状態とし、外部からレンズあるいは光ファイバ
によって光波4を入力させ、半導体光増幅器に結合させ
ることにより、増幅光波5を得ることができる。この様
にして、内部ゲイン20〜30dBを達成している。Thus, the semiconductor optical amplifier having the graded composition film 2 formed on the end face of the semiconductor laser can achieve a reflectance of 0.1% or less by measuring the gain ripple. As shown in FIG. 1, the semiconductor optical amplifier is set to a constant current injection state that is slightly smaller than the threshold current, the optical wave 4 is input from the outside by a lens or an optical fiber, and is coupled to the semiconductor optical amplifier to obtain an amplified optical wave 5. be able to. In this way, the internal gain of 20 to 30 dB is achieved.
【0028】[0028]
【実施例2】図5は上記例のデバイスを、波長多重送受
信システムに適用した場合のシステム概念図である。同
図において、10は上記の光増幅器、11は送信部、1
2は受信部、13、14はそれぞれ合波・分波器、15
は伝送光ファイバである。こうした構成により、波長8
30nmおよび840nmの信号を多重化し、光増幅器
10で高ゲイン、低リップルで増幅し、100Mbps
以上の伝送速度でクロストークのない信号の授受が可能
となる。Second Embodiment FIG. 5 is a system conceptual diagram when the device of the above example is applied to a wavelength division multiplexing transmission / reception system. In the figure, 10 is the above optical amplifier, 11 is a transmitter, and 1
2 is a receiver, 13 and 14 are multiplexers / demultiplexers, and 15
Is a transmission optical fiber. With this configuration, the wavelength of 8
The signals of 30 nm and 840 nm are multiplexed, amplified by the optical amplifier 10 with high gain and low ripple, and 100 Mbps.
It is possible to exchange signals without crosstalk at the above transmission rates.
【0029】以上述べたように、光通信システムなどに
用いられる光信号を、直接、増幅するための高帯域半導
体光増幅器が得られるが、その入出力端面の保護膜兼反
射防止膜の傾斜組成膜2を含む2層膜を、実例として、
以下に詳細に記述する。As described above, a high-bandwidth semiconductor optical amplifier for directly amplifying an optical signal used in an optical communication system or the like can be obtained. The gradient composition of the protective film / antireflection film on the input / output end face thereof is obtained. As an example, a two-layer film including the film 2 is used.
The details are described below.
【0030】[0030]
【実例1−3】図4に示すような2元同時スパッタも可
能な高周波スパッタ装置において、ターゲット61は1
25mmφのSi3N4、ターゲット62は同サイズの
Al2O3を使用した。到達真空度は5×10−6to
rr以下、スパッタ電力は100W〜1KW、スパッタ
ガス圧は1〜10×10−3torr、スパッタガス種
はArを用いた。[Example 1-3] In the high frequency sputtering apparatus capable of performing two-way simultaneous sputtering as shown in FIG.
25 mmφ Si 3 N 4 and the target 62 used Al 2 O 3 of the same size. The ultimate vacuum is 5 × 10 −6 to
rr or less, the sputtering power was 100 W to 1 kW, the sputtering gas pressure was 1 to 10 × 10 −3 torr, and the sputtering gas species was Ar.
【0031】半導体レーザデバイス63を基板ホルダー
64に設置して、基板ホルダー64を矢印65に示す方
向にゆっくり回転させながら、Si3N4とAl2O3
の傾斜組成膜2を半導体レーザの端面に積層した。次
に、半導体レーザデバイス63を、ターゲット62上に
なるように配置して、ターゲット61上のシャッターを
閉じる、あるいは、ターゲット61への投入電力を0に
して、Al2O3のみを続けて積層し、2層膜の反射防止
膜を形成した。The semiconductor laser device 63 is placed on the substrate holder 64, and Si 3 N 4 and Al 2 O 3 are slowly rotated while the substrate holder 64 is rotated in the direction shown by the arrow 65.
The gradient composition film 2 was laminated on the end face of the semiconductor laser. Next, the semiconductor laser device 63 is arranged so as to be on the target 62, and the shutter on the target 61 is closed, or the input power to the target 61 is set to 0 and only Al 2 O 3 is continuously laminated. Then, a two-layer antireflection film was formed.
【0032】更に、Si3N4ターゲット61とAl2
O3ターゲット62への投入スパッタ電力Pを変えるこ
とで、3種類の傾斜組成膜を積層した。各傾斜組成膜2
の平均屈折率n、膜厚d1、Al2O3膜3の膜厚d2、
反射率Rを表1に示す。また、2層膜の第1層目の傾斜
組成膜2をXPS(軟X線光電子分光法)により膜厚方
向に分析した。測定した元素の測定軌道は、Si2p、A
l2pである。実例1の測定結果を、横軸にレーザ端面か
らの距離、縦軸にSi2p、Al2pから換算したSi3N
4、Al2O3の量からのSi3N4の組成比をとっ
て、図6に示す。Further, the Si 3 N 4 target 61 and the Al 2
By changing the input sputtering power P to the O 3 target 62, three types of gradient composition films were laminated. Each gradient composition film 2
Average refractive index n, film thickness d 1 , film thickness d 2 of Al 2 O 3 film 3,
The reflectance R is shown in Table 1. Further, the first gradient composition film 2 of the two-layer film was analyzed in the film thickness direction by XPS (soft X-ray photoelectron spectroscopy). The measured trajectories of the measured elements are Si 2p , A
l 2p . The measurement result of Example 1 is the distance from the laser end face on the horizontal axis, and Si 3 N converted from Si 2p and Al 2p on the vertical axis.
4 , the composition ratio of Si 3 N 4 from the amount of Al 2 O 3 is shown in FIG.
【0033】耐久性能は、半導体レーザの出力を20m
Wとし、70°Cの環境下に5000時間放置した時の
半導体レーザへの注入電流値の変化により評価した。注
入電流値がほぼ0に低下した場合と、注入電流値が初期
値の2倍以上必要になった場合を素子の故障とみなし、
その故障数によって、◎印:故障数、全品の5%以下、
○印:故障数、全品の10%以下、△印:故障数、全品
の10%超とする。The durability performance is 20 m when the output of the semiconductor laser is
It was evaluated by the change of the injection current value to the semiconductor laser when it was set to W and left to stand in an environment of 70 ° C. for 5000 hours. When the injection current value is reduced to almost 0 and when the injection current value is required to be more than twice the initial value, it is regarded as an element failure,
Depending on the number of failures, ◎: Number of failures, 5% or less of all products,
◯: Number of failures, 10% or less of all products, Δ: Number of failures, more than 10% of all products.
【0034】なお、比較例1として半導体レーザデバイ
スを隔壁板66の上方の位置に設置して、基板ホルダー
を回転させないで積層したSi3N4とAl2O3の混
合膜を第1層とし次にAl2O3膜を続いて積層した2
層膜の結果も表1に示す。この比較例1の第1層のXP
Sの測定結果も図6に表す。As Comparative Example 1, the semiconductor laser device was installed above the partition plate 66, and the mixed film of Si 3 N 4 and Al 2 O 3 laminated without rotating the substrate holder was used as the first layer. Next, an Al 2 O 3 film was successively laminated 2
The results of the layer film are also shown in Table 1. XP of the first layer of Comparative Example 1
The measurement result of S is also shown in FIG.
【0035】[0035]
【表1】 以上の結果、Si3N4とAl2O3との傾斜組成膜2
を第1層としAl2O3膜を第2層3とする反射防止膜
は、端面反射率0.1%以下を達成でき、かつ耐久性能
も比較例1の混合膜を第1層とする構成の反射防止膜よ
り向上することがわかった。[Table 1] As a result of the above, the gradient composition film 2 of Si 3 N 4 and Al 2 O 3
Is the first layer, and the Al 2 O 3 film is the second layer 3. The antireflection film can achieve end face reflectance of 0.1% or less, and has the durability performance of the mixed film of Comparative Example 1 as the first layer. It was found that the antireflection film having the structure is improved.
【0036】[0036]
【実例4−6】実例1〜3におけるSi3N4ターゲッ
トの代わりにAlNターゲットを用いた以外、同様な手
順で、AlNとAl2O3の傾斜組成膜2を積層し次に
Al2O3膜3を続いて積層した2層膜の結果を実例4
〜6として表2に示す。比較例2は、比較例1と同様に
して、AlNとAl2O3の混合膜を第1層とし次にA
l2O3膜を続いて積層した2層膜の結果も表2に示
す。[Illustrative 4-6] except for using an AlN target instead the Si 3 N 4 target in examples 1-3, in a similar procedure, AlN and Al 2 graded composition layer 2 of the O 3 stacked next Al 2 O Example 4 shows the result of a two-layer film in which three films 3 are successively laminated.
Are shown in Table 2 as ~ 6. In Comparative Example 2, as in Comparative Example 1, a mixed film of AlN and Al 2 O 3 was used as the first layer, and then A
Table 2 also shows the results of the two-layer film in which the l 2 O 3 film was successively laminated.
【0037】[0037]
【表2】 以上の結果、AlNとAl2O3との傾斜組成膜2を第
1層としAl2O3膜3を第2層とする反射防止膜は、
端面反射率0.1%以下を達成でき、かつ耐久性能も比
較例2の混合膜を第1層とする構成の反射防止膜より向
上することがわかった。[Table 2] As a result, the antireflection film having the gradient composition film 2 of AlN and Al 2 O 3 as the first layer and the Al 2 O 3 film 3 as the second layer is
It was found that the end face reflectance of 0.1% or less can be achieved, and the durability performance is also improved as compared with the antireflection film having the mixed film of Comparative Example 2 as the first layer.
【0038】[0038]
【実例7−9】実施例1〜3におけるSi3N4ターゲ
ットの代わりに、Si3N4:AlN=50:50の混
合焼結体ターゲットSi3N4−AlNを用いた以外、
同様な手順で、Si3N4−AlNとAl2O3の傾斜
組成膜2を積層し次にAl2O3膜3を続いて積層した
2層膜の結果を実施例7〜9として表3に示す。比較例
3は、比較例1と同様にして、Si3N4とAlNとA
l2O3の混合膜を第1層とし次にAl2O3膜を続い
て積層した2層膜の結果も表3に示す。[Illustrative 7-9] Instead the Si 3 N 4 target in Examples 1~3, Si 3 N 4: AlN = 50: except that a 50 mixed sintered body target Si 3 N 4 -AlN of
The results of the two-layer film in which the gradient composition film 2 of Si 3 N 4 -AlN and Al 2 O 3 was laminated by the same procedure and then the Al 2 O 3 film 3 was subsequently laminated are shown as Examples 7 to 9. 3 shows. Comparative Example 3 is similar to Comparative Example 1, and Si 3 N 4 , AlN and A
Table 3 also shows the results of a two-layer film in which the mixed film of l 2 O 3 was used as the first layer, and then the Al 2 O 3 film was subsequently laminated.
【0039】[0039]
【表3】 以上の結果、Si3N4とAlNの混合材料と、Al2
O3との傾斜組成膜2を第1層としAl2O3膜3を第
2層とする反射防止膜は、端面反射率0.1%以下を達
成でき、かつ耐久性能も比較例3の混合膜を第1層とす
る構成の反射防止膜より向上することがわかった。[Table 3] As a result, the mixed material of Si 3 N 4 and AlN and Al 2
The antireflection film having the gradient composition film 2 with O 3 as the first layer and the Al 2 O 3 film 3 as the second layer can achieve end face reflectance of 0.1% or less, and has durability performance of Comparative Example 3 as well. It was found that the mixed film was improved compared to the antireflection film having the first layer.
【0040】[0040]
【発明の効果】以上説明したように、本発明によれば、
半導体レーザ構造などの光半導体素子の端面に、特定の
材料からなる傾斜組成膜を含む2層の光学膜材料を積層
することにより、水分や酸素による端面酸化を押さえら
れる。更に、半導体レーザなどの素子と2層膜の熱膨張
係数の違いによる素子の劣化を押さえることにより、耐
久性能を向上させると共に、傾斜組成膜を含む2層膜の
それぞれの膜厚、屈折率等を適宜選ぶことにより、端面
反射率を0.1%以下にすることが可能になる。As described above, according to the present invention,
By stacking two layers of optical film material including a gradient composition film made of a specific material on the end surface of an optical semiconductor element such as a semiconductor laser structure, end surface oxidation due to moisture or oxygen can be suppressed. Furthermore, by suppressing deterioration of the element such as a semiconductor laser due to the difference in thermal expansion coefficient between the element and the two-layer film, durability performance is improved, and the film thickness and refractive index of the two-layer film including the gradient composition film are improved. It is possible to reduce the end face reflectance to 0.1% or less by properly selecting.
【図1】本発明の光学膜材料を用いた半導体光増幅器の
斜視図。FIG. 1 is a perspective view of a semiconductor optical amplifier using an optical film material of the present invention.
【図2】本発明の光学膜材料を用いた半導体レーザデバ
イスの断面図。FIG. 2 is a sectional view of a semiconductor laser device using the optical film material of the present invention.
【図3】本発明の光学膜材料を用いた半導体レーザデバ
イスの縦断面図。FIG. 3 is a longitudinal sectional view of a semiconductor laser device using the optical film material of the present invention.
【図4】本発明の光学膜材料を積層する製膜装置の簡略
図。FIG. 4 is a simplified diagram of a film forming apparatus for laminating the optical film material of the present invention.
【図5】光通信システムにより、波長多重化伝送を行う
例のブロック図。FIG. 5 is a block diagram of an example of performing wavelength division multiplexing transmission by an optical communication system.
【図6】本発明の傾斜組成膜のXSP測定による組成分
布例。FIG. 6 shows an example of composition distribution of the graded composition film of the present invention measured by XSP.
【図7】従来例を示す図。FIG. 7 is a diagram showing a conventional example.
1,10 リッジ型半導体光増幅器 2 第1層目の傾斜組成膜 3 第2層目の膜 4 入力光 5 増幅光波 11 送信部 12 受信部 13 合波器 14 分波器 15 伝送光ファイバ 21 基板 22,24 クラッド層 23 活性層 25 キャップ層 26 絶縁層 27,28 電極 61,62 ターゲット 63 半導体素子 64 ホルダー基板 65 半導体素子の移動方向 66 隔壁板 1, 10 Ridge-type semiconductor optical amplifier 2 Gradient composition film of the first layer 3 Film of the second layer 4 Input light 5 Amplified light wave 11 Transmitter 12 Receiver 13 Combiner 14 Demultiplexer 15 Transmission optical fiber 21 Substrate 22, 24 Clad layer 23 Active layer 25 Cap layer 26 Insulating layer 27, 28 Electrode 61, 62 Target 63 Semiconductor element 64 Holder substrate 65 Moving direction of semiconductor element 66 Partition plate
Claims (2)
半導体レーザ構造を有する半導体光増幅器において、該
光学膜は、2層の誘電体薄膜の組み合わせからなり、該
半導体レーザ構造端面側の第1の薄膜は、AlN、Si
3N4から選ばれる少なくとも1種の材料と、Al2O3の
材料との膜からなり、該AlN、Si3N4から選ばれる
少なくとも1種の材料の組成濃度は、半導体レーザ構造
端面側が大きく、膜厚方向に徐々に組成濃度が減少し、
かつAl2O3の組成濃度は、半導体レーザ構造端面側が
小さく、膜厚方向に徐々に組成濃度が増加し、平均屈折
率が1.90より大きい傾斜組成膜であり、第2の薄膜
はAl2O3の材料からなることを特徴とする半導体光増
幅器。1. A semiconductor optical amplifier having a semiconductor laser structure having an input / output end face provided with an antireflection optical film, wherein the optical film is composed of a combination of two dielectric thin films, and the semiconductor laser structure end face side is provided. The first thin film is AlN, Si
It is composed of a film of at least one material selected from 3 N 4 and Al 2 O 3 , and the composition concentration of at least one material selected from AlN and Si 3 N 4 is such that the end face side of the semiconductor laser structure is Large, composition concentration gradually decreases in the film thickness direction,
In addition, the composition concentration of Al 2 O 3 is small on the end face side of the semiconductor laser structure, the composition concentration gradually increases in the film thickness direction, and the average refractive index is a graded composition film larger than 1.90. A semiconductor optical amplifier comprising a material of 2 O 3 .
いて、該光学膜は、2層の誘電体薄膜の組み合わせから
なり、該光半導体素子端面側の第1の薄膜は、窒化アル
ミニウム、窒化シリコンから選ばれる少なくとも1種の
材料と、酸化アルミニウムの材料との膜からなり、該窒
化アルミニウム、窒化シリコンから選ばれる少なくとも
1種の材料の組成濃度は、光半導体素子端面側が大き
く、膜厚方向に徐々に組成濃度が減少し、かつ酸化アル
ミニウムの組成濃度は、光半導体素子端面側が小さく、
膜厚方向に徐々に組成濃度が増加し、第2の薄膜は酸化
アルミニウムの材料からなることを特徴とする光半導体
素子。2. An optical semiconductor element having an end face provided with an optical film, wherein the optical film comprises a combination of two layers of dielectric thin films, and the first thin film on the end face side of the optical semiconductor device is aluminum nitride or nitride. It is composed of a film of at least one material selected from silicon and a material of aluminum oxide. The composition concentration of at least one material selected from aluminum nitride and silicon nitride is large on the end face side of the optical semiconductor element and in the film thickness direction. The composition concentration gradually decreases, and the composition concentration of aluminum oxide is small on the end face side of the optical semiconductor element,
An optical semiconductor element, wherein the composition concentration gradually increases in the film thickness direction, and the second thin film is made of a material of aluminum oxide.
Priority Applications (1)
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JP12573294A JPH07312459A (en) | 1994-05-16 | 1994-05-16 | Optical semiconductor element |
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JP12573294A JPH07312459A (en) | 1994-05-16 | 1994-05-16 | Optical semiconductor element |
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JPH07312459A true JPH07312459A (en) | 1995-11-28 |
Family
ID=14917421
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Country Status (1)
Country | Link |
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JP (1) | JPH07312459A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003086352A (en) * | 2001-09-10 | 2003-03-20 | Semiconductor Energy Lab Co Ltd | Light emitting device and electronic device |
WO2004015168A1 (en) * | 2002-08-09 | 2004-02-19 | Ube Industries, Ltd. | Material coated with thin ceramic film having graded composition and method for production thereof |
US8735192B2 (en) | 2005-12-16 | 2014-05-27 | Sharp Kabushiki Kaisha | Nitride semiconductor light emitting device and method of fabricating nitride semiconductor laser device |
US9660413B2 (en) | 2006-03-08 | 2017-05-23 | Sharp Kabushiki Kaisha | Nitride semiconductor light emitting device |
-
1994
- 1994-05-16 JP JP12573294A patent/JPH07312459A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003086352A (en) * | 2001-09-10 | 2003-03-20 | Semiconductor Energy Lab Co Ltd | Light emitting device and electronic device |
WO2004015168A1 (en) * | 2002-08-09 | 2004-02-19 | Ube Industries, Ltd. | Material coated with thin ceramic film having graded composition and method for production thereof |
US7494693B2 (en) | 2002-08-09 | 2009-02-24 | Ube Industries, Ltd. | Ceramic thin film coating material having slope constitution and process for the production thereof |
US8735192B2 (en) | 2005-12-16 | 2014-05-27 | Sharp Kabushiki Kaisha | Nitride semiconductor light emitting device and method of fabricating nitride semiconductor laser device |
US9660413B2 (en) | 2006-03-08 | 2017-05-23 | Sharp Kabushiki Kaisha | Nitride semiconductor light emitting device |
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