JP2004296845A - Quantum well structure, semiconductor light emitting element, optical transmitting module, and optical transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the increase of net strain and the shifting of the light-emitting wavelength to the shorter wavelength side in a quantum well structure, and to improve on the interfacial roughness between a GaInNAs quantum well layer and barrier layers. <P>SOLUTION: The quantum well structure comprises a quantum well layer 104a, which contains In, N, and other group V elements and has a compression strain, and barrier layers, which are formed on the top and bottom sides of the quantum well layer 104a. In this quantum well structure, each of the barrier layers comprises a layer 104b, which contains In and P and adjoins the quantum well layer 104a, and a layer 104c, which has a tensile strain and is laminated on the layer 104b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a quantum well structure, a semiconductor light emitting device, an optical transmission module, and an optical transmission system.
[0002]
[Prior art]
Research and development using a mixed crystal semiconductor (nitrogen-based V-group mixed crystal semiconductor) material containing nitrogen and other V-group elements as V-group elements has been conducted as a semiconductor laser device for optical communication in the 1.3 μm band or 1.55 μm band. Has been done. For example, Patent Literature 1 discloses a GaInNAs-based semiconductor laser including nitrogen and arsenic as group V elements. By using such a nitrogen-based group V mixed crystal semiconductor material for the active layer, a long-wavelength semiconductor laser of 1.3 μm or 1.55 μm band can be formed on a GaAs substrate.
[0003]
However, since nitrogen having a small atomic radius has low miscibility with other Group V elements, it is difficult to obtain good crystal quality as the nitrogen addition amount is increased. For this reason, there has been a problem that the luminous efficiency decreases as the amount of added nitrogen increases. In order to solve this, it has been studied to reduce the amount of nitrogen added to the GaInNAs active layer. However, in order to obtain long-wavelength light emission of 1.3 μm or more with a GaInNAs material without increasing the amount of added nitrogen, it is necessary to increase the compressive strain of GaInNAs to 2% or more. When such GaInNAs is used for the quantum well structure, GaAs is usually used as the barrier layer.
[0004]
When a high-strain quantum well layer having a compressive strain of 2% or more is used as an active layer of a semiconductor laser, reliability of the semiconductor laser element becomes an important issue, and as a means for solving this, a strain compensation structure is being studied. . The strain compensation structure is a method of reducing the net strain (netstrain) of the entire quantum well structure by giving the barrier layer strain in the direction opposite to the strain of the quantum well layer. The GaInNAs well layer has a compressive strain, and as the strain compensation layer, GaNAs or GaAsP having a tensile strain is used.
[0005]
For example, Patent Literature 2 describes a semiconductor laser having a GaInNAsSb well layer and a GaNAs barrier layer. Non-Patent Document 1 reports a semiconductor laser having a GaInNAs well layer and a GaAsP strain compensation layer.
[0006]
Further, in the GaInNAs / GaAs quantum well structure and the GaInNAs / GaNAs quantum well structure, at the interface between the GaInNAs well layer and the GaAs or GaNAs barrier layer, interdiffusion of In and Ga occurs after annealing, and the interface roughness increases. (See Non-Patent Document 2).
[0007]
In order to improve the interface between the GaInNAs well layer and the barrier layer, Non-Patent Document 3 discloses that a GaInAs intermediate layer is provided between the GaInNAs well layer and the GaAs barrier layer. Non-Patent Document 2 reports that a GaInNAs diffusion preventing layer is provided between a GaInNAs well layer and a GaNAs barrier layer.
[0008]
Also, in Patent Document 3, Ga _x1 In _1-x1 N _y1 As _1-y1 (0 <x1 ≦ 1, 0 <y1 <1) Quantum Well Layer and Ga _x2 In _1-x2 As _y2 P _1-y2 (0 ≦ x2 ≦ 1, 0 ≦ y2 ≦ 1) A semiconductor element having a quantum well structure including a barrier layer has been proposed. Here, when 0 <x1 ≦ 0.5, 0.5 × x1 ≦ x2 ≦ 1.5 × x1 is satisfied, and when 0.5 <x1 ≦ 1, 0.5 × (1-x1) ≦ 1−x2 ≦ 1.5 × (1−x1) is satisfied. This suppresses the diffusion of In by reducing the concentration gradient of the In composition between the well layer and the barrier layer.
[0009]
[Patent Document 1]
JP-A-8-195522
[0010]
[Patent Document 2]
JP-A-2002-118329
[0011]
[Non-patent document 1]
Appl. Phys. Lett. , Vol. 78, p. 91 (2001)
[0012]
[Non-patent document 2]
Appl. Phys. Lett. , Vol. 80, p. 4720 (2002)
[0013]
[Non-Patent Document 3]
IEEE Photon. Technol. Lett. , Vol. 14, p. 896 (2002)
[0014]
[Patent Document 3]
JP 2001-251021A
[0015]
[Problems to be solved by the invention]
However, the GaInAs intermediate layer reported in Non-Patent Document 3 has an In composition of 32% and a high compressive strain of 2.3%. The GaInNAs diffusion preventing layer reported in Non-Patent Document 2 also has a high compressive strain amount of 1.84%.
[0016]
Therefore, the GaInAs intermediate layer or the GaInNAs diffusion preventing layer provided at the interface between the GaInNAs well layer and the barrier layer does not function as a strain compensation layer. When the thickness of the GaInNAs well layer is the same, the provision of a high-strain intermediate layer rather increases the net strain.
[0017]
In addition, in order to provide an intermediate layer with the same net strain, it is necessary to reduce the thickness of the GaInNAs quantum well layer, which causes a problem that the emission wavelength is shortened by the quantum effect.
[0018]
In Patent Document 3, when the GaInAsP barrier layer is lattice-matched with the GaAs substrate or has a tensile strain, the band gap of the barrier layer becomes larger than the band gap of GaAs. Since the level rises and the emission wavelength becomes shorter, the nitrogen composition must be increased in order to match the emission wavelength, and there is a problem that the crystallinity is reduced. On the other hand, when the GaInAsP barrier layer is made to have a compressive strain, a material in which the band gap of the barrier layer does not become larger than the band gap of GaAs can be used, but a strain compensation structure cannot be formed, and net The strain greatly increases.
[0019]
The present invention relates to a quantum well structure and a semiconductor light emitting device capable of suppressing an increase in the net strain of the quantum well structure, a short wavelength shift of the emission wavelength, and improving the interface roughness between the GaInNAs quantum well layer and the barrier layer. And an optical transmission module and an optical transmission system.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 includes a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and a barrier layer formed above and below the quantum well layer. In the constructed quantum well structure, the barrier layer is characterized in that a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain are laminated.
[0021]
According to a second aspect of the present invention, there is provided a quantum well structure including a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and barrier layers formed above and below the quantum well layer. Wherein the barrier layer is formed by laminating a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain. I have.
[0022]
According to a third aspect of the present invention, in the semiconductor light emitting device of the second aspect, the layer containing In and phosphorus (P) adjacent to the quantum well layer has a band gap energy equal to or less than that of GaAs. It is characterized by.
[0023]
According to a fourth aspect of the present invention, in the semiconductor light emitting device of the second aspect, a layer containing In and phosphorus (P) adjacent to the quantum well layer has a strain amount of ± 0.1% or less. Features.
[0024]
According to a fifth aspect of the present invention, in the semiconductor light emitting device of the second aspect, the barrier layer includes a composition gradient layer.
[0025]
According to a sixth aspect of the present invention, in the semiconductor light emitting device according to any one of the second to fifth aspects, the active layer has a multiple quantum well structure.
[0026]
According to a seventh aspect of the present invention, in the semiconductor light emitting device according to any one of the second to sixth aspects, the semiconductor light emitting device is a surface emitting semiconductor laser device.
[0027]
According to an eighth aspect of the present invention, in the semiconductor light emitting device according to any one of the second to seventh aspects, the layer containing In and phosphorus (P) adjacent to the quantum well layer is GaInAsP. It is characterized by:
[0028]
According to a ninth aspect of the present invention, there is provided an optical transmission module using the semiconductor light emitting device according to any one of the second to eighth aspects.
[0029]
According to a tenth aspect of the present invention, there is provided an optical transmission system using the optical transmission module according to the ninth aspect.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0031]
(1st Embodiment)
The quantum well structure according to the first embodiment of the present invention includes a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and barrier layers formed above and below the quantum well layer. In the quantum well structure described above, the barrier layer is formed by laminating a layer containing In and phosphorus (P) adjacent to the quantum well layer (a layer functioning as an intermediate layer) and a layer having a tensile strain. It is characterized by:
[0032]
It is known that a mixed crystal semiconductor containing nitrogen and another Group V element, that is, a nitrogen-based Group V mixed crystal semiconductor has a very large bowing parameter in relation to band gap energy and lattice constant. Therefore, in a region where the nitrogen composition is small, a phenomenon occurs in which the band gap energy decreases as the lattice constant decreases.
[0033]
GaN has a higher band gap energy than GaAs, but in a region of a low nitrogen composition, the band gap energy is lower than that of GaAs. As a result, a long-wavelength light emitting layer can be formed on the GaAs substrate.
[0034]
Also, the band gap energy can be reduced by adding In. Therefore, a nitrogen-based group V mixed crystal semiconductor containing In can emit light in a long wavelength band with a smaller nitrogen composition than that when In is not contained. Therefore, a decrease in luminous efficiency caused by an increase in the nitrogen composition can be suppressed. GaInNAs, GaInNAsP, GaInNAsSb, GaInNAsPSb, or the like can be used as a material of the quantum well layer containing In, nitrogen, and another group V element and having a compressive strain.
[0035]
However, since the lattice constant difference between InAs and GaAs is as much as 7.2%, the amount of compressive strain with respect to a GaAs substrate increases as the In composition increases. For example, in the GaInNAs quantum well layer in the 1.3 μm band, the amount of compressive strain is as large as 2.0 to 2.6%.
[0036]
In the quantum well structure of the present invention, the barrier layers formed above and below the quantum well layer have a layer containing In and phosphorus (P) adjacent to the quantum well layer (a layer functioning as an intermediate layer) and a tensile strain. And the layers are stacked.
[0037]
The layer having a tensile strain has a strain in a direction opposite to the compressive strain of the quantum well layer, and thus has a strain compensation structure that reduces the net strain (net strain) of the entire quantum well structure. Thereby, generation of dislocations can be suppressed, and the reliability of the quantum well structure can be improved. As a material of the layer having a tensile strain, it is possible to use GaAsP, GaNAs, GaNAsP, AlGaAsP, or the like. In addition, a small amount of In or Sb can be added to the material.
[0038]
Further, in the barrier layer, a layer adjacent to the quantum well layer (a layer functioning as an intermediate layer) contains In. Thereby, at the interface between the quantum well layer containing In and the barrier layer, interdiffusion between In of the quantum well layer and Ga on the barrier layer side can be suppressed. Therefore, the roughness of the interface between the quantum well layer and the barrier layer can be reduced.
[0039]
However, when In is included, the barrier layer adjacent to the quantum well layer has a large lattice constant. Therefore, when GaInAs or GaInNAs is provided at the interface as in the conventional example, there arises a problem that the net strain of the entire quantum well structure increases.
[0040]
Therefore, the present invention is characterized in that the barrier layer adjacent to the quantum well layer contains phosphorus (P) in addition to In. By adding P, the lattice constant of the mixed crystal semiconductor is reduced, so that the strain amount of the barrier layer adjacent to the quantum well layer can be reduced. Thereby, an increase in the net strain of the entire quantum well structure can be suppressed, and good reliability can be ensured.
[0041]
The layer (intermediate layer) containing In and phosphorus (P) adjacent to the quantum well layer is provided to suppress interdiffusion of In and Ga, and has a thin layer thickness of about 0.5 to 5 nm. Works well.
[0042]
The barrier layer has at least a two-layer structure of a layer (intermediate layer) containing In and phosphorus (P) adjacent to the quantum well layer and a layer having tensile strain. However, it is not always necessary to have two layers, and it may be formed by combining two or more multilayer structures having different mixed crystal compositions.
[0043]
The quantum well structure of the first embodiment can be used for a gain layer of an optical amplifier, a light absorption layer of a light receiving element, and a modulation layer of an optical modulator, in addition to the active layer of the light emitting element.
[0044]
(Second embodiment)
The semiconductor light emitting device according to the second embodiment of the present invention includes a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and barrier layers formed above and below the quantum well layer. In the semiconductor light emitting device having the quantum well structure as an active layer, the barrier layer includes a layer containing In and phosphorus (P) adjacent to the quantum well layer (a layer functioning as an intermediate layer) and a layer having a tensile strain. Are laminated. That is, the quantum well structure described in the first embodiment is used for the active layer of the semiconductor light emitting device.
[0045]
Accordingly, since the active layer has a strain compensation structure, the net strain of the entire quantum well structure can be reduced, and the reliability of the semiconductor light emitting device can be improved.
[0046]
Further, since the barrier layer adjacent to the quantum well layer contains In, at the interface between the barrier layer and the quantum well layer containing In, the In of the quantum well layer and the Ga on the barrier layer side are in contact with each other. Mutual diffusion can be suppressed. Therefore, the roughness of the interface between the quantum well layer and the barrier layer can be reduced. Therefore, the light emission characteristics of a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain can be improved.
[0047]
Further, since the interface between the quantum well layer and the barrier layer can be formed steeply, the amount of short wavelength shift of the active layer due to annealing is reduced. Therefore, in order to obtain the same emission wavelength, the amount of strain or the amount of nitrogen added to the quantum well layer can be reduced. Therefore, the reliability or the luminous efficiency can be further improved.
[0048]
Further, in the present invention, the barrier layer adjacent to the quantum well layer contains phosphorus (P) in addition to In, so that the strain amount of the barrier layer adjacent to the quantum well layer can be reduced. Therefore, the barrier layer adjacent to the quantum well layer can reduce the increase in the net strain of the entire quantum well structure and the roughness of the interface between the quantum well layer and the barrier layer as compared with the conventional structure.
[0049]
(Third embodiment)
According to the third embodiment of the present invention, in the semiconductor light emitting device of the second embodiment, the band gap energy of the layer containing In and phosphorus (P) adjacent to the quantum well layer (the layer functioning as an intermediate layer) is: It is characterized by being equal to or lower than the band gap energy of GaAs.
[0050]
By setting the bandgap energy of the layer containing In and phosphorus (P) adjacent to the quantum well layer to be equal to or smaller than the bandgap energy of GaAs, the bandgap energy of the layer having a tensile strain is higher than that of GaAs. Even if it is large, it is possible to suppress an increase in the quantum level of the quantum well layer. Therefore, the quantum well active layer having the strain compensation structure can be formed while suppressing the short wavelength shift of the emission wavelength.
[0051]
When the layer containing In and phosphorus (P) adjacent to the quantum well layer is formed of, for example, GaInAsP, it is necessary to reduce the compressive strain in order to make the band gap energy of GaInAsP equal to or less than the band gap energy of GaAs. However, even in this case, since the amount of compressive strain can be reduced as compared with the GaInAs intermediate layer and the GaInNAs diffusion preventing layer shown in the conventional example, there is an effect of suppressing an increase in net strain.
[0052]
For example, Ga _0.65 In _0.35 N _0.01 As _0.99 Is a quantum well layer, and a layer having a thickness of 2 nm is formed as a layer adjacent to the quantum well layer. _0.8 In _0.2 As _0.8 P _0.2 Using GaAs as a layer having a tensile strain. _0.85 P _0.15 Consider the case where is used. Ga _0.8 In _0.2 As _0.8 P _0.2 Have a bandgap energy slightly smaller than GaAs. On the other hand, GaAs _0.85 P _0.15 Has a tensile strain of 0.53% and a band gap energy of about 100 meV higher than that of GaAs.
[0053]
When the quantum well layer thickness is 4 to 10 nm, the conduction band quantum level is Ga _0.65 In _0.35 N _0.01 As _0.99 Is a quantum well layer, and the value is almost the same as that of a quantum well structure using GaAs as a barrier layer. Therefore, even when the band gap energy of the layer having the tensile strain is larger than that of GaAs, the short wavelength shift of the emission wavelength is suppressed by setting the band gap energy of the layer adjacent to the quantum well layer to the band gap energy of GaAs or less. can do.
[0054]
Note that Ga adjacent to the quantum well layer _0.8 In _0.2 As _0.8 P _0.2 Is 0.73%. This value can be reduced to half or less of the compressive strain of 1.8 to 2.3% of the GaInAs intermediate layer and the GaInNAs diffusion preventing layer shown in the conventional example.
[0055]
(Fourth embodiment)
According to the fourth embodiment of the present invention, in the semiconductor light emitting device of the second embodiment, the strain amount of a layer containing In and phosphorus (P) adjacent to the quantum well layer (a layer functioning as an intermediate layer) is ±. 0.1% or less.
[0056]
As the In composition increases, the lattice constant of the mixed crystal increases. On the other hand, as the P composition increases, the lattice constant of the mixed crystal decreases. Therefore, by controlling the composition of In and P in the layer containing In and phosphorus (P) adjacent to the quantum well layer, the layer has a lattice constant almost equal to that of the GaAs substrate, that is, the strain amount is ± 0.1%. The following layers can be formed.
[0057]
Therefore, in the fourth embodiment, the quantum well layer has a compressive strain, the barrier layer includes a layer having a tensile strain, and a layer having a strain amount of ± 0.1% or less is formed between them. Structure. For this reason, since the layer having the strain in the reverse direction does not directly contact, dislocation is hardly generated at the interface, and the reliability of the semiconductor light emitting device can be further improved.
[0058]
When, for example, GaInAsP is used as the layer containing In and phosphorus (P) adjacent to the quantum well layer, the band gap energy of GaInAsP lattice-matched to the GaAs substrate becomes larger than that of GaAs. Therefore, if the entire barrier layer is made of lattice-matched GaInAsP as in Patent Document 3, the band discontinuity with the quantum well layer becomes large, and the emission wavelength shifts to a short wavelength due to the quantum effect.
[0059]
However, in the present invention, the barrier layer is formed by laminating a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain outside the layer. By reducing the layer thickness of the layer adjacent to the quantum well layer to 0.5 to 2 nm and making the band gap energy of the layer having a tensile strain outside the layer smaller than the band gap energy of the layer adjacent to the quantum well layer. In addition, it is possible to reduce the short wavelength shift of the quantum well layer.
[0060]
For example, Ga _0.65 In _0.35 N _0.01 As _0.99 Is a quantum well layer, and a layer having a thickness of 1 nm is formed as a layer adjacent to the quantum well layer. _0.7 In _0.3 As _0.4 P _0.6 Using GaN as a layer having a tensile strain _0.01 As _0.89 P _0.1 Consider the case where is used. Ga _0.7 In _0.3 As _0.4 P _0.6 Has a composition substantially lattice-matched with GaAs, and the conduction band edge position is higher by 300 meV than GaAs. On the other hand, GaN _0.01 As _0.89 P _0.1 Has a tensile strain of 0.55%, and the conduction band edge position is about 80 meV lower than that of GaAs. The conduction band quantum level when the quantum well layer thickness is 8 nm is Ga _0.65 In _0.35 N _0.01 As _0.99 Is only about 4 meV as compared with the case of a quantum well structure using GaAs as a barrier layer and GaAs as a barrier layer. Therefore, even when the band gap energy of the layer adjacent to the quantum well layer is larger than that of GaAs, a short wavelength shift of the emission wavelength can be suppressed by reducing the thickness of the layer adjacent to the quantum well layer.
[0061]
As a material of the layer having a tensile strain, GaAsP, GNAs, AlGaAsP, or the like can be used in addition to GANAsP described in the example.
[0062]
(Fifth embodiment)
The fifth embodiment of the present invention is characterized in that, in the semiconductor light emitting device of the second embodiment, the barrier layer includes a gradient composition layer.
[0063]
For example, in the barrier layer, a layer containing In and phosphorus (P) adjacent to the quantum well layer is made a composition gradient layer, or a composition gradient layer is placed between a layer containing In and phosphorus (P) and a layer having tensile strain. Can also be provided.
[0064]
In the case where the layer containing In and phosphorus (P) adjacent to the quantum well layer is a composition gradient layer, strain is continuously generated between the quantum well layer having compressive strain and the barrier layer having tensile strain. It becomes possible to laminate while changing. Similarly, also when a composition gradient layer is provided between a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain, the strain is continuously changed at the interface between them. Can be stacked. This eliminates a sharp change in the lattice constant in the stacked structure, so that dislocation is less likely to occur at the interface, and the reliability is further improved.
[0065]
(Sixth embodiment)
The sixth embodiment of the present invention is characterized in that in the semiconductor light emitting device of any of the second to fifth embodiments, the active layer has a multiple quantum well structure.
[0066]
In a multiple quantum well structure in which quantum well layers having high strain are stacked in multiple layers, lattice relaxation is more likely to occur as the number of wells increases. In the present invention, the barrier layer adjacent to the quantum well layer contains phosphorus (P) in addition to In, thereby reducing the amount of compressive strain of the barrier layer adjacent to the quantum well layer and providing a layer having tensile strain. This forms a distortion compensation structure. Therefore, the net strain of the entire quantum well structure can be reduced, and a semiconductor light emitting device having high reliability can be realized even if a multiple quantum well structure in which quantum well layers having high strain are stacked in multiple layers is used for the active layer. it can.
[0067]
(Seventh embodiment)
In the seventh embodiment of the present invention, the semiconductor light emitting device of any one of the second to sixth embodiments is a surface emitting semiconductor laser device (a pair of multilayer mirrors and a pair of multilayer mirrors). (A surface-emitting type semiconductor laser device including a cavity structure).
[0068]
The surface-emitting type semiconductor laser has a longer resonator length and a smaller gain region than the end-face type semiconductor laser. Therefore, in order to improve the laser characteristics such as the threshold current, the maximum light output, and the temperature characteristics, it is necessary to increase the number of quantum well active layers and increase the gain of the active layers.
[0069]
The active layer of the present invention has a strain compensation structure by imparting tensile strain to the barrier layer. In the barrier layer, a layer containing In and phosphorus (P) adjacent to the quantum well layer reduces the amount of compressive strain. Thereby, lattice relaxation can be suppressed, and the number of quantum wells can be increased. Therefore, it is possible to realize a surface emitting semiconductor laser which oscillates at a low threshold current, has a high maximum optical output, and has good temperature characteristics.
[0070]
(Eighth embodiment)
The eighth embodiment of the present invention is characterized in that, in the semiconductor light emitting device of any of the second to seventh embodiments, the layer containing In and phosphorus (P) adjacent to the quantum well layer is GaInAsP. And
[0071]
Group III elements include Al in addition to Ga and In. However, if an Al-containing layer is provided at the interface with the nitrogen-containing quantum well layer, chemically active Al and nitrogen are easily bonded, and nitrogen segregates at the interface. Therefore, the flatness of the interface between the quantum well layer and the barrier layer is deteriorated. Therefore, it is preferable that the layer containing In and phosphorus (P) adjacent to the quantum well layer does not contain Al.
[0072]
Further, as group V elements, there are Sb and N in addition to As and P, and these elements can be included. However, the addition of Sb increases the lattice constant. Therefore, in order to suppress an increase in the amount of compressive strain, it is desirable to reduce the Sb composition.
[0073]
Further, when nitrogen is added, the position of the conduction band edge is greatly reduced, so that the confinement of electrons in the quantum well layer is reduced. Therefore, when adding the N composition, it is desirable to add a trace amount.
[0074]
Therefore, as a material system of the barrier layer adjacent to the quantum well layer of the present invention, GaInAsP is a mixed crystal semiconductor composed of the least number of elements.
[0075]
(Ninth embodiment)
The optical transmission module according to the ninth embodiment of the present invention is characterized in that any one of the second to eighth semiconductor light emitting elements is used.
[0076]
The semiconductor light emitting devices of the second to eighth embodiments have a high luminous efficiency and a highly reliable quantum well active layer, and therefore have a low operating current and high reliability. In the ninth embodiment, by using this semiconductor light emitting element for an optical transmission module, an optical transmission module with low power consumption and high reliability can be configured.
[0077]
(Tenth embodiment)
The optical transmission system according to the tenth embodiment of the present invention is characterized in that the optical transmission module according to the ninth embodiment is used. In the tenth embodiment, by using an optical transmission module with low power consumption and high reliability, the power consumption of the optical transmission system can be reduced and a highly reliable optical transmission system can be configured.
[0078]
【Example】
Hereinafter, examples of the present invention will be described.
[0079]
(First embodiment)
FIGS. 1A and 1B are views showing a semiconductor laser device according to a first embodiment of the present invention. FIG. 1B is a diagram showing details of the quantum well active layer 104 in the semiconductor laser device of FIG. 1A.
[0080]
Referring to FIG. 1A, on an n-type GaAs substrate 101, an n-type AlGaAs cladding layer 102, a GaAs lower optical waveguide 103, a quantum well active layer 104, a GaAs upper optical waveguide layer 105, and a p-type AlGaAs cladding layer 106. , A p-type GaAs contact layer 107 are sequentially stacked. A p-side electrode 108 is formed on the surface of the p-type GaAs contact layer 107, and an n-side electrode 109 is formed on the back surface of the n-type GaAs substrate 101.
[0081]
The feature of the semiconductor laser device of the first embodiment lies in the quantum well structure used for the active layer 104. That is, referring to FIG. 1B, the quantum well active layer 104 has a structure in which GaInNAs is used as the quantum well layer 104a and the upper and lower sides thereof are sandwiched by barrier layers. Here, the barrier layer includes a GaInAsP intermediate layer 104b and a GaAsP layer 104c.
[0082]
Here, the thickness of the GaInNAs quantum well layer 104a was 8 nm, the thickness of the GaAsP layer 104c was 20 nm, and the thickness of the GaInAsP intermediate layer 104b was 2 nm.
[0083]
The GaInNAs quantum well layer 104a has a band gap energy of 1.3 μm band, and is a semiconductor laser device oscillating in 1.3 μm band. The GaInNAs quantum well layer 104a has a larger lattice constant than the GaAs substrate and has a high compressive strain of 2.3%.
[0084]
On the other hand, the GaAsP layer 104c has a tensile strain of 0.3%. Therefore, the GaInNAs quantum well layer 104a has a strain compensation structure that alleviates the high compressive strain. Thereby, the strain relaxation of the GaInNAs quantum well layer 104a is suppressed, and the reliability of the semiconductor laser device is improved.
[0085]
Further, the GaInAsP intermediate layer 104b provided between the GaInNAs quantum well layer 104a and the GaAsP layer 104c contains In, and is an interface between the GaInNAs quantum well layer 104a containing In and the GaAsP layer 104c not containing In. , Thereby suppressing the interdiffusion between In and Ga. Thus, the roughness of the interface between the GaInNAs quantum well layer 104a and the GaAsP layer 104c is reduced, and the luminous efficiency of the GaInNAs quantum well layer 104a is improved.
[0086]
Further, since the interface between the GaInNAs quantum well layer 104a and the barrier layer can be formed steeply, the amount of short wavelength shift of the oscillation wavelength due to annealing is reduced. Therefore, to obtain the same emission wavelength, the amount of nitrogen added to the GaInNAs quantum well layer 104a can be reduced, so that the emission efficiency can be further improved.
[0087]
Further, the present invention is characterized in that the GaInAsP intermediate layer 104b contains P in addition to In. By adding P, the amount of compressive strain of the GaInAsP intermediate layer 104b can be reduced as compared with the case where P is not added.
[0088]
FIGS. 2A, 2B, and 2C are diagrams showing an energy diagram and a strain amount profile at a conduction band edge position of the quantum well structure.
[0089]
FIG. 2A is a diagram showing a conduction band diagram and a strain profile of a conventional quantum well active layer. A GaInAs quantum well layer having a thickness of 8 nm is sandwiched between a GaInAs intermediate layer 2 nm and a GaAsP layer. It is a case where it is provided. In the structure of FIG. 2A, a GaInNAs quantum well layer having a compressive strain of 2.3% and a GaInAs layer having a compressive strain of 2.0% are laminated, so that the high compressive strain region is as thick as 12 nm in total. . Therefore, the critical thickness is exceeded, and dislocations occur in the quantum well structure.
[0090]
FIG. 2B is a diagram showing a conduction band diagram and a strain profile of another conventional quantum well active layer. A GaInAs intermediate layer 2 nm is interposed between a GaInNAs quantum well layer having a thickness of 4 nm. , A GaAsP layer. In FIG. 2B, the high compressive strain region has a total thickness of 8 nm, which is smaller than the critical film thickness. However, since the thickness of the GaInNAs quantum well layer is as thin as 4 nm, the quantum level of the conduction band becomes high, and a problem arises that the emission wavelength shifts to a short wavelength even with GaInNAs having the same composition.
[0091]
On the other hand, FIG. 2C is a diagram showing a conduction band diagram and a strain amount profile of the quantum well active layer of the first embodiment. The GaInNAs quantum well layer having a thickness of 8 nm has a GaInAsP intermediate layer of 2 nm. Thus, a GaAsP layer is provided. Here, since the GaInAsP intermediate layer contains P, the amount of compressive strain can be reduced as compared with GaInAs having the same In composition. Therefore, unlike the structure of FIG. 2A, the occurrence of dislocation can be suppressed by reducing the net strain. Further, unlike the structure of FIG. 2B, it is not necessary to reduce the thickness of the GaInNAs quantum well layer, so that a short wavelength shift of the emission wavelength can be suppressed.
[0092]
The compressive strain of the GaInAs intermediate layer can be reduced by reducing the In composition of the intermediate layer. However, when the In composition is reduced, the effect of suppressing the interdiffusion of Ga and In at the quantum well interface decreases. In order to suppress the interdiffusion between Ga and In, it is necessary to make the In composition of the intermediate layer and the In composition of the quantum well layer as close as possible. Therefore, the conventional structure cannot reduce the amount of compressive strain of the intermediate layer while suppressing the interdiffusion of Ga and In. According to the present invention, the net strain can be reduced without impairing the effect of suppressing the interdiffusion between Ga and In, and the reliability of the semiconductor laser can be improved.
[0093]
(Second embodiment)
FIG. 3 is a view showing a surface emitting semiconductor laser device according to a second embodiment of the present invention. Referring to FIG. 3, on an n-type GaAs substrate 101, an n-type GaAs / AlGaAs distributed Bragg reflector (DBR) 301 is laminated. Here, the n-type GaAs / AlGaAs DBR 301 is composed of an n-type GaAs high refractive index layer and an n-type Al _0.9 Ga _0.1 As low-refractive-index layers are alternately laminated with a layer thickness of １ ／ of the wavelength in the medium. On the n-type GaAs / AlGaAs DBR 301, a GaAs lower spacer layer 302, a multiple quantum well active layer 303, a GaAs upper spacer layer 304, a p-type AlAs layer 305, and a p-type GaAs / AlGaAs DBR 306 are sequentially stacked.
[0094]
A mesa structure is formed by etching the surface of the above-mentioned laminated structure into a cylindrical shape until the n-type GaAs / AlGaAs DBR 301 is reached. Then, the AlAs layer 305 is selectively oxidized from the side of the mesa structure to form AlO _x An insulating region 307 is formed.
[0095]
A ring-shaped p-side electrode 108 is formed on the surface of the mesa structure except for the light extraction region. On the back surface of the n-type GaAs substrate 101, an n-side electrode 109 is formed.
[0096]
FIG. 4A is a diagram showing in detail a stacked structure of a multiple quantum well active layer in a surface emitting semiconductor laser device according to a second embodiment of the present invention. In FIG. 4A, reference numeral 303a denotes an 8 nm-thick GaInNAs quantum well layer. The amount of compressive strain of the GaInNAs quantum well layer 303a is 2.3%. A GaInAsP intermediate layer 303b having a thickness of 2 nm is provided adjacent to the GaInNAs quantum well layer 303a, and a GaAsP strain compensation layer 303c having a thickness of 27 nm is stacked outside the intermediate layer 303b. The tensile strain of the GaAsP strain compensation layer 303c was set to 0.4%. The number of quantum well layers was three.
[0097]
FIG. 4B is a diagram illustrating an energy diagram at a conduction band edge position of the multiple quantum well active layer. The multiple quantum well active layer according to the second embodiment is characterized in that the band gap energy of the GaInAsP intermediate layer 303b is set to be equal to or less than the band gap energy of GaAs.
[0098]
The GaAsP strain compensation layer 303c is larger than the band gap energy of GaAs. Therefore, in the case of the GaInNAs quantum well layer / GaAsP barrier layer, the emission wavelength is shifted by several tens of nm shorter than the structure of the GaInNAs quantum well layer / GaAs barrier layer. However, in the structure of FIG. 4, a GaInAsP intermediate layer 303b having a band gap energy equal to or lower than the band gap energy of GaAs is provided. This suppresses an increase in the quantum level.
[0099]
FIG. 8 is a diagram showing the relationship between the conduction band quantum level (ground level) and the well width. 8, a black square indicates a quantum level in the quantum well structure shown in FIG. 4, and a dotted line indicates a quantum level in the case of a GaInNAs quantum well layer / GaAs barrier layer. The conduction band edge of the GaInAsP intermediate layer was 30 meV lower than GaAs, and the conduction band edge of the GaAsP strain compensation layer was 100 meV higher than GaAs.
[0100]
As shown in FIG. 8, even when a GaAsP strain compensation layer having a higher energy barrier than GaAs is used, a quantum level almost equivalent to that of the GaInNAs / GaAs quantum well structure can be obtained by inserting a GaInAsP intermediate layer of 2 nm. ing. Therefore, a short wavelength shift of the emission wavelength can be suppressed.
[0101]
FIG. 4C shows a strain amount profile of the multiple quantum well active layer. When the band gap energy of GaInAsP is lower than the band gap energy of GaAs, the lattice constant becomes larger than that of GaAs, resulting in compressive strain. For example, Ga _0.8 In _0.2 As _0.8 P _0.2 Is used for the intermediate layer, the band gap energy is slightly smaller than that of GaAs, and the amount of compressive strain is 0.73%. Therefore, Ga not containing P _0.8 In _0.2 The amount of compressive strain can be reduced by half compared to the amount of compressive strain of As (1.43%). Thus, the net strain can be reduced from 0.2% to 0.14%.
[0102]
(Third embodiment)
The surface emitting semiconductor laser device according to the third embodiment of the present invention is similar to the structure shown in FIG. The third embodiment differs from the second embodiment in the structure of the multiple quantum well active layer.
[0103]
FIG. 5A is a diagram showing in detail a stacked structure of a multiple quantum well active layer in the surface emitting semiconductor laser device of the third embodiment. In FIG. 5A, reference numeral 501a denotes an 8 nm-thick GaInNAs quantum well layer. A GaInAsP intermediate layer 501b having a thickness of 1 nm is provided adjacent to the GaInNAs quantum well layer 501a, and a GaAsP strain compensation layer 501c having a layer thickness of 27 nm is stacked outside the intermediate layer 501b. The number of quantum well layers was three.
[0104]
FIG. 5B shows a strain amount profile of the multiple quantum well active layer. The amount of compressive strain of the GaInNAs quantum well layer 501a is set to 2.3%, and GaN _0.009 As _0.89 P _0.1 The strain compensation layer 501c has a tensile strain of 0.5%. The GaInAsP intermediate layer 501b is characterized in that it has a mixed crystal composition substantially lattice-matched with the GaAs substrate.
[0105]
As a composition that is substantially lattice-matched with the GaAs substrate, for example, Ga _0.7 In _0.3 As _0.4 P _0.6 There is. The In composition of the GaInNAs quantum well layer 501a is about 0.3 to 0.35. _0.7 In _0.3 As _0.4 P _0.6 The intermediate layer 501b has a value close to the In composition of the GaInNAs quantum well layer 501a. Thereby, interdiffusion between Ga and In can be suppressed at the interface of the GaInNAs quantum well layer 501a.
[0106]
In the structure shown in FIG. 5B, the net strain is reduced to + 0.1% by the distortion compensation structure. In addition, since the non-strained intermediate layer 501b is provided between the GaInNAs quantum well layer 501a having a compressive strain and the GaNasP strain compensation layer 501c having a tensile strain, the layer having the strain in the opposite direction comes into direct contact. And dislocation generation at the interface is suppressed. Thereby, the reliability of the semiconductor laser device can be further improved.
[0107]
FIG. 5C is a diagram showing an energy diagram at the conduction band edge position of the multiple quantum well active layer 501. Ga lattice-matched to the GaAs substrate _0.7 In _0.3 As _0.4 P _0.6 Is about 300 meV higher than that of GaAs. Therefore, as shown in FIG. 5C, in the GaInAsP intermediate layer 501b, the energy barrier of electrons becomes high. Also, GaN _0.009 As _0.89 P _0.1 The conduction band edge position of the strain compensation layer 501c is lower than GaAs by 80 meV.
[0108]
When the barrier layer is formed by increasing the thickness of the GaInAsP intermediate layer 501b, the conduction band edge discontinuity with the GaInNAs quantum well layer 501a increases, so that the conduction band quantum level increases and the emission wavelength becomes shorter. A shift occurs. However, in the structure shown in FIG. 5, the thickness of the GaInAsP intermediate layer 501b having a high energy barrier is made as thin as 1 nm, and a GaNAsP strain compensation layer 501c is provided outside the GaInAsP intermediate layer 501b as a barrier layer. Thereby, an increase in the quantum level can be suppressed.
[0109]
FIG. 9 is a diagram showing the relationship between the conduction band quantum level (ground level) and the well width. In FIG. 9, white circles indicate quantum levels in the quantum well structure shown in FIG. 5, and dotted lines indicate quantum levels in the case of a GaInNAs quantum well layer / GaAs barrier layer. As shown in FIG. 9, even when the GaInAsP intermediate layer 501b having a high energy barrier is provided, a quantum level substantially equal to that of the GaInNAs / GaAs quantum well structure is obtained. Therefore, a short wavelength shift of the emission wavelength can be suppressed.
[0110]
(Fourth embodiment)
The surface emitting semiconductor laser device according to the fourth embodiment of the present invention is similar to the structure shown in FIG. The fourth embodiment is different from the surface emitting semiconductor laser devices shown in the second and third embodiments in the structure of the multiple quantum well active layer.
[0111]
FIG. 6A is a diagram showing in detail a stacked structure of a multiple quantum well active layer in a surface emitting semiconductor laser device according to a fourth embodiment of the present invention. In FIG. 6A, reference numeral 601a denotes a GaInNAs quantum well layer having a thickness of 8 nm. The amount of compressive strain of the GaInNAs quantum well layer 601a is 2.3%. A GaInAsP composition gradient layer 601b having a thickness of 2 nm is provided adjacent to the GaInNAs quantum well layer 601a, and a GaAsP strain compensation layer 601c having a thickness of 27 nm is further stacked outside the GaInAsP composition gradient layer 601b. The tensile strain amount of the GaAsP strain compensation layer 601c was set to 0.4%. The number of quantum well layers was three.
[0112]
FIG. 6B shows a strain amount profile of the multiple quantum well active layer. Ga _1-x In _x As _1-y P _y In the composition gradient layer 601b, both the In composition x and the As composition y are gradually changed, and the strain amount is continuously changed. This eliminates a sharp change in the lattice constant at the interface, thereby suppressing the generation of dislocations at the interface of the quantum well layer and improving the reliability of the semiconductor laser.
[0113]
(Fifth embodiment)
FIG. 7 is a diagram illustrating an optical transmission system according to a fifth embodiment of the present invention. In the optical transmission system of FIG. 7, an optical signal generated by the optical transmission module 701 is transmitted to the optical reception module 702 through the quartz optical fiber 704. In FIG. 7, two lines of an optical transmission module 701, an optical fiber 704, and an optical reception module 702 are provided so that bidirectional communication can be performed. The optical transmitting module 701 and the optical receiving module 702 are integrated in one package and constitute an optical transmitting / receiving device 703.
[0114]
The fifth embodiment is characterized in that the semiconductor laser device of any one of the first to fourth embodiments is used as the light source of the optical transmission module 701. As described above, the above semiconductor laser suppresses the interdiffusion of In and Ga at the interface between the GaInNAs quantum well layer and the barrier layer, thereby reducing the roughness of the interface and reducing the roughness of the GaInNAs quantum well layer. The luminous efficiency is improved. Therefore, the operating current of the semiconductor laser can be reduced, and the power consumption of the optical transmission module can be reduced.
[0115]
Further, by reducing the net strain of the quantum well active layer having the strain compensation structure and improving the reliability of the semiconductor laser, a highly reliable optical transmission module can be configured.
[0116]
Thereby, the power consumption of the optical transmission system can be reduced, and a highly reliable optical transmission system can be configured.
[0117]
【The invention's effect】
As described above, according to the first aspect of the invention, a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and a barrier layer formed above and below the quantum well layer are provided. In the quantum well structure having the structure described above, the barrier layer is formed by stacking a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain, and the barrier layer has a quantum well structure. When the layer adjacent to the well layer contains In, the interdiffusion between In of the quantum well layer and Ga on the barrier layer side can be suppressed, and the roughness of the interface between the quantum well layer and the barrier layer can be reduced. Furthermore, since the barrier layer adjacent to the quantum well layer contains phosphorus (P) at the same time, the amount of compressive strain is reduced, and the increase in netstrain of the entire quantum well structure can be suppressed. Further, the barrier layer includes a layer having a tensile strain, and can constitute a strain compensation structure to improve the reliability of the quantum well structure.
[0118]
According to the second aspect of the present invention, a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and a barrier layer formed above and below the quantum well layer is provided. In a semiconductor light emitting device having a well structure as an active layer, the barrier layer is formed by laminating a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having tensile strain. In the configuration, since the active layer has a strain compensation structure, the reliability of the semiconductor light emitting device can be improved.
[0119]
Further, since the roughness of the interface between the quantum well layer and the barrier layer can be reduced, the light emission characteristics of the quantum well layer can be improved. In addition, since the interface between the quantum well layer and the barrier layer can be formed steeply, the amount of short wavelength shift of the active layer due to annealing is reduced, and in order to obtain the same emission wavelength, the amount of strain or the amount of added nitrogen of the quantum well layer is reduced. Can be reduced. Therefore, the reliability or the luminous efficiency can be further improved.
[0120]
Furthermore, since the barrier layer adjacent to the quantum well layer contains phosphorus (P) in addition to In, the amount of strain in the barrier layer adjacent to the quantum well layer can be reduced, and the net strain of the entire quantum well structure can be reduced. There is no increase.
[0121]
According to the third aspect of the present invention, in the semiconductor light emitting device according to the second aspect, the layer containing In and phosphorus (P) adjacent to the quantum well layer has a band gap energy equal to or less than that of GaAs. Therefore, even when the band gap energy of the layer having a tensile strain is larger than the band gap energy of GaAs, a short wavelength shift of the emission wavelength can be suppressed, and a highly efficient active layer can be formed.
[0122]
According to the fourth aspect of the present invention, in the semiconductor light emitting device according to the second aspect, the layer containing In and phosphorus (P) adjacent to the quantum well layer has a strain amount of ± 0.1% or less. This is characterized in that a layer having a strain in the opposite direction does not come into direct contact, so that dislocation is less likely to occur at the interface, and the reliability of the semiconductor light emitting element can be further improved.
[0123]
Further, even when the band gap energy of the layer adjacent to the quantum well layer is larger than that of GaAs, a short wavelength shift of the emission wavelength can be suppressed by reducing the thickness of the layer adjacent to the quantum well layer.
[0124]
According to the fifth aspect of the present invention, in the semiconductor light emitting device described in the second embodiment, since the barrier layer includes the composition gradient layer, a steep change in the lattice constant in the stacked structure is eliminated, and the interface is not changed. Dislocation generation can be suppressed, and the reliability can be further improved.
[0125]
According to a sixth aspect of the present invention, in the semiconductor light emitting device according to any one of the second to fifth aspects, the active layer has a multiple quantum well structure. By reducing the amount of compressive strain in the barrier layer adjacent to the substrate and forming a strain compensation structure, high reliability can be achieved even if a multiple quantum well structure in which quantum well layers with high strain are stacked in multiple layers is used for the active layer. Semiconductor light emitting device having the following.
[0126]
According to a seventh aspect of the present invention, in the semiconductor light emitting element according to any one of the second to sixth aspects, the semiconductor light emitting element is a surface emitting semiconductor laser element, and the pair of multilayer films In a surface-emitting type semiconductor laser device including a resonator structure sandwiched between reflectors, the resonator structure includes the quantum well structure of the present invention as an active layer, thereby suppressing lattice relaxation and increasing the number of quantum wells. Therefore, a surface emitting semiconductor laser which oscillates at a low threshold current, has a high maximum light output, and has good temperature characteristics can be realized.
[0127]
According to an eighth aspect of the present invention, in the semiconductor light emitting device according to any one of the second to seventh aspects, the layer containing In and phosphorus (P) adjacent to the quantum well layer is made of GaInAsP. Therefore, the interface flatness between the quantum well layer and the barrier layer is good, the amount of compressive strain can be reduced, and a barrier layer with good electron confinement in the quantum well layer can be formed.
[0128]
According to the ninth aspect of the present invention, the semiconductor light emitting device according to any one of the second to eighth aspects is used, so that an optical transmission module with low power consumption and high reliability is provided. Can be.
[0129]
According to the tenth aspect of the present invention, since the optical transmission module according to the ninth aspect is used, the power consumption of the optical transmission system can be reduced, and a highly reliable optical transmission system can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a semiconductor laser according to a first embodiment.
FIG. 2 is a diagram illustrating an energy diagram and a strain amount profile at a conduction band edge position of a quantum well structure.
FIG. 3 is a diagram showing a surface emitting semiconductor laser according to a second embodiment.
FIG. 4 is a diagram showing a laminated structure, a strain profile, and a conduction band diagram of a multiple quantum well active layer according to a second embodiment.
FIG. 5 is a diagram showing a stacked structure, a conduction band diagram, and a strain amount profile of a multiple quantum well active layer according to a third embodiment.
FIG. 6 is a diagram showing a laminated structure and a strain profile of a multiple quantum well active layer according to a fourth embodiment.
FIG. 7 is a configuration diagram of an optical transmission system according to a fifth embodiment.
FIG. 8 is a diagram showing the relationship between the conduction band quantum level and the well width in the multiple quantum well active layer of the second embodiment.
FIG. 9 is a diagram showing the relationship between the conduction band quantum level and the well width in the multiple quantum well active layer of the third embodiment.
[Explanation of symbols]
101 n-type GaAs substrate
102 n-type AlGaAs cladding layer
103 GaAs lower optical waveguide layer
104 Quantum well active layer
105 GaAs upper optical waveguide layer
106 p-type AlGaAs upper cladding layer
107 p-type GaAs contact layer
108 p-side electrode
109 n-side electrode
104a GaInNAs quantum well layer
104b GaInAsP intermediate layer
104c GaAsP strain compensation layer
301 n-type GaAs / AlGaAs lower DBR
302 GaAs lower spacer layer
303 Multiple quantum well active layer
304 GaAs upper spacer layer
305 AlAs layer
306 p-type GaAs / AlGaAs upper DBR
307 AlO _x Insulation area
303a GaInNAs quantum well layer
303b GaInAsP intermediate layer
303c GaAsP strain compensation layer
501a GaInNAs quantum well layer
501b GaInAsP intermediate layer
501c GaNAsP strain compensation layer
601a GaInNAs quantum well layer
601b GaInAsP composition gradient layer
601c GaAsP strain compensation layer
701 Optical transmission module
702 Optical receiving module
703 Optical transceiver
704 quartz optical fiber

Claims (10)

In a quantum well structure including a quantum well layer containing In, nitrogen, and another group V element and having a compressive strain, and barrier layers formed above and below the quantum well layer, the barrier layer is a quantum well layer A layer containing In and phosphorus (P) and a layer having a tensile strain, which are adjacent to each other, are laminated. In a semiconductor light emitting device including a quantum well layer including In, nitrogen and another group V element and having a compressive strain, and a barrier layer formed above and below the quantum well layer and having a quantum well structure as an active layer, The semiconductor light emitting device according to claim 1, wherein the barrier layer is formed by laminating a layer containing In and phosphorus (P) adjacent to the quantum well layer and a layer having a tensile strain. 3. The semiconductor light emitting device according to claim 2, wherein the layer containing In and phosphorus (P) adjacent to the quantum well layer has a band gap energy equal to or smaller than that of GaAs. 3. The semiconductor light emitting device according to claim 2, wherein the layer containing In and phosphorus (P) adjacent to the quantum well layer has a strain of ± 0.1% or less. 3. The semiconductor light emitting device according to claim 2, wherein the barrier layer includes a composition gradient layer. The semiconductor light emitting device according to any one of claims 2 to 5, wherein the active layer has a multiple quantum well structure. The semiconductor light emitting device according to claim 2, wherein the semiconductor light emitting device is a surface emitting semiconductor laser device. 8. The semiconductor light emitting device according to claim 2, wherein the layer containing In and phosphorus (P) adjacent to the quantum well layer is GaInAsP. 9. An optical transmission module, comprising the semiconductor light emitting device according to claim 2. An optical transmission system using the optical transmission module according to claim 9.

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