JP4178901B2 - Semiconductor optical device and method of manufacturing semiconductor optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor optical device and a method for manufacturing the semiconductor optical device.
[0002]
[Prior art]
Semiconductor light emitting devices are used as light sources for optical communications and optical amplifiers. In the field of optical communication, a semiconductor modulation element is used for modulating light from a light source. The semiconductor light emitting device and the semiconductor modulation device include a plurality of semiconductor layers and a pair of electrodes. Each of the plurality of semiconductor layers is provided on the substrate and is made of a III-V group compound semiconductor. The pair of electrodes is used for supplying carriers to a plurality of semiconductor layers.
[0003]
[Problems to be solved by the invention]
The inventors have studied a semiconductor optical device composed of a III-V group compound semiconductor, and in particular, a quaternary III-V group compound semiconductor (hereinafter referred to as a quaternary III-V group compound semiconductor containing gallium element, indium element, arsenic element, and nitrogen element). Focuses on GaInNAs semiconductor). However, this quaternary III-V group compound semiconductor has an immiscible region in the phase diagram, which makes it difficult to grow a GaInNAs semiconductor. In the experiment, the inventors have investigated that a ternary III-V compound semiconductor (hereinafter referred to as a GaInNAsP semiconductor) containing a gallium element, an indium element, an arsenic element, a phosphorus element, and a nitrogen element grows more than a GaInNAs semiconductor. I found it easy.
[0004]
The inventors have been conducting research for manufacturing a semiconductor optical device including a GaInNAsP semiconductor. Specifically, the inventors are examining the production of a semiconductor optical device having a quantum well structure including a GaInNAsP semiconductor and a GaAs semiconductor. In this examination, the inventors may replace phosphorus atoms (P) and arsenic atoms (As) at the interface between the GaAs semiconductor and the GaInNAsP semiconductor when forming a junction between the GaAs semiconductor and the GaInNAsP semiconductor. I discovered that there is. Further investigation has found that this substitution can also occur at the interface between a semiconductor layer that contains arsenic as a group V and does not contain phosphorus, and a semiconductor layer that contains arsenic and phosphorus as a group V. .
[0005]
An object of the present invention is to provide a semiconductor optical device having a structure in which substitution of phosphorus atoms (P) and arsenic atoms (As) hardly occurs at an interface between two semiconductor layers, and a method for manufacturing the semiconductor optical device. To do.
[0006]
[Means for Solving the Problems]
  One aspect of the present invention relates to a semiconductor optical device. The semiconductor optical device includes a compound semiconductor portion and a GaAs substrate. The compound semiconductor portion includes first to fifth compound semiconductor layers. The first compound semiconductor layer is provided on the second compound semiconductor layer. Each of the first compound semiconductor layers includes one or more kinds of group III elements, arsenic elements, and phosphorus elements. The second compound semiconductor layer contains a gallium element, an indium element, a nitrogen element, an arsenic element, and a phosphorus element. The third compound semiconductor layer includes one or more kinds of group III elements, arsenic elements, and phosphorus elements. The fourth compound semiconductor layer is made of a GaInP semiconductor. The fifth compound semiconductor layer is made of a GaInP semiconductor. The GaAs substrate carries the first to fifth compound semiconductor layers. The fourth compound semiconductor layer is a cladding layer, the fifth compound semiconductor layer is a cladding layer, the second compound semiconductor layer is composed of a GaInNAsP semiconductor, and the first and third compound semiconductor layers are,Each of the first and third compound semiconductor layers is composed of any one of a GaNPAs semiconductor and an AlGaInAsP semiconductor, and each of the first and third compound semiconductor layers is larger than the band gap of the GaInNAsP semiconductor and the GaAs semiconductor. The layers are provided such that the second compound semiconductor layer forms a well layer and the first and third compound semiconductor layers form a quantum well structure that forms a barrier layer. The compound semiconductor layer is provided between the fourth compound semiconductor layer and the fifth compound semiconductor layer.
[0007]
According to still another aspect of the present invention, a semiconductor optical device includes a first conductivity type semiconductor part, a second conductivity type semiconductor part, and a compound semiconductor part. The compound semiconductor part is provided between the first conductive type semiconductor part and the second conductive type semiconductor part. The compound semiconductor portion includes first and second compound semiconductor layers. The first compound semiconductor layer is provided on the second compound semiconductor layer. Each of the first compound semiconductor layers includes one or more kinds of group III elements, arsenic elements, and phosphorus elements. The second compound semiconductor layer contains a gallium element, an indium element, a nitrogen element, an arsenic element, and a phosphorus element.
[0008]
According to still another aspect of the present invention, a semiconductor optical device includes a first conductivity type semiconductor part, a second conductivity type semiconductor part, first and second compound semiconductor layers, and a third compound semiconductor layer. With. The first conductivity type semiconductor part includes a plurality of first conductivity type semiconductor layers provided so as to form a multilayer reflective film. The second conductivity type semiconductor part includes a plurality of second conductivity type semiconductor layers provided so as to form a multilayer reflective film. The first and second compound semiconductor layers are provided between the first conductivity type semiconductor part and the second conductivity type semiconductor part. The second compound semiconductor layer is provided on the first compound semiconductor layer. The first compound semiconductor layer contains one or a plurality of types of group III elements, arsenic elements, and phosphorus elements. The second compound semiconductor layer contains a gallium element, an indium element, a nitrogen element, an arsenic element, and a phosphorus element.
[0009]
In the above semiconductor optical device, since the first and second compound semiconductor layers contain an arsenic element and a phosphorus element, phosphorus atoms (P) and arsenic are interposed between the first compound semiconductor layer and the second compound semiconductor layer. Substitution with atoms (As) hardly occurs.
[0010]
The semiconductor optical device according to the present invention can further include a third compound semiconductor layer containing one or more kinds of Group III elements, arsenic elements, and phosphorus elements. The first to third compound semiconductor layers constitute a quantum well structure. This semiconductor optical device has a quantum well structure having a sharp junction.
[0011]
In the semiconductor optical device according to the present invention, the third compound semiconductor layer can be composed of a GaInNAsP semiconductor.
[0012]
In the semiconductor optical device according to the present invention, each of the first compound semiconductor layers may be composed of a GaInAsP semiconductor, and the second compound semiconductor layer may be composed of a GaInNAsP semiconductor.
[0013]
A semiconductor optical device according to the present invention includes a third compound semiconductor layer containing one or more kinds of group III elements, arsenic elements, and phosphorus elements, a first conductivity type semiconductor portion, and a second conductivity type semiconductor portion. Can be further provided. The first conductive type semiconductor part and the second conductive type semiconductor part are made of a semiconductor material lattice-matched to the GaAs semiconductor. The third compound semiconductor layer includes one or more kinds of group III elements, arsenic elements, and phosphorus elements. The first to third compound semiconductor layers are provided so as to constitute a quantum well structure. In the quantum well structure, the second compound semiconductor layer constitutes a well layer and the first and third compound semiconductor layers constitute a barrier layer. The composition of the group III element, the arsenic element, and the phosphorus element in the first and third compound semiconductor layers is determined so that each of the first and third compound semiconductor layers has one of compressive strain and tensile strain. Has been. The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the second compound semiconductor layer is determined so that the second compound semiconductor layer has the other strain of compressive strain and tensile strain. .
[0014]
Since a semiconductor junction having a sharp composition change can be obtained at the interface of the semiconductor layer between the first and third compound semiconductor layers and the second compound semiconductor layer, a good strained quantum well structure can be obtained. it can.
[0015]
In the semiconductor optical device according to the present invention, the first to third compound semiconductor layers are provided so as to constitute a quantum well structure. In the quantum well structure, the second compound semiconductor layer constitutes a well layer and the first and third compound semiconductor layers constitute a barrier layer. The composition of the group III element, arsenic element, and phosphorus element in the first and third compound semiconductor layers is such that the lattice constants of the semiconductors constituting each of the first and third compound semiconductor layers do not lattice match with the GaAs semiconductor. Has been determined. The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the second compound semiconductor layer is determined so that the lattice constant of the semiconductor constituting the second compound semiconductor layer does not lattice match with the GaAs semiconductor. ing. The average lattice constant of the semiconductor constituting the barrier layer and the semiconductor constituting the well layer substantially matches the lattice constant of the GaAs semiconductor.
[0016]
As a whole, the amount of strain is substantially canceled out in the quantum well structure portion, and the number of stacked layers of the well layer and the barrier layer is not restricted due to the strain in the quantum well structure portion.
[0017]
In the semiconductor optical device according to the present invention, the first and third compound semiconductor layers are composed of GaNPAs semiconductors. The second compound semiconductor layer is made of a GaInNAsP semiconductor.
[0018]
When the GaNPAs semiconductor is configured to have tensile strain, the band gap of the GaNPAs semiconductor can be reduced. This GaNPAs semiconductor acts to reduce the quantum effect in the quantum well structure. This makes it possible to shift the wavelength of the generated light to a long wavelength.
[0019]
In the semiconductor optical device according to the present invention, the first and second compound semiconductor layers are composed of GaPAs semiconductors. The third compound semiconductor layer is made of a GaInNAsP semiconductor. The band gap of the GaPAs semiconductor is larger than that of the GaAs semiconductor. In the GaPAs semiconductor, carriers are confined in the quantum well structure. Therefore, the temperature characteristics of the semiconductor optical device are improved.
[0020]
In the semiconductor optical device according to the present invention, the first to third compound semiconductor layers may be provided so as to constitute a quantum well structure. The well layer has one of compressive strain and tensile strain. The barrier layer has a strain of the other of the compressive strain and the tensile strain. The quantum well structure is configured such that the amount of strain in the well layer is substantially equal to the amount of strain in each barrier layer. In this semiconductor optical device, the strain amounts in the well layer and the barrier layer substantially cancel each other, and the number of well layers and barrier layers is not limited due to the strain stress.
[0021]
In the semiconductor optical device according to the present invention, it is preferable that the band gaps of the first and second compound semiconductor layers are larger than the band gaps of the GaInNAsP semiconductor and the GaAs semiconductor. Due to the larger band gap, the ability of the first and second compound semiconductor layers to confine carriers in the third compound semiconductor layer is improved. As a result, a semiconductor optical device with less temperature dependence is obtained. Each of the first and second compound semiconductor layers is preferably substantially lattice matched to the GaAs semiconductor. This semiconductor optical device can be obtained by using, for example, an AlGaInAsP semiconductor as each of the first and second compound semiconductor layers.
[0022]
In the semiconductor optical device according to the present invention, the first conductivity type semiconductor part includes a fourth compound semiconductor layer, and the second conductivity type semiconductor part includes a fifth compound semiconductor layer. Each of the fourth and fifth compound semiconductor layers is made of a GaInP semiconductor. In this semiconductor optical device, the band gap of the GaInP semiconductor can be made larger than the band gaps of the first and third compound semiconductor layers. Further, the refractive index of the GaInP semiconductor can be made smaller than the refractive indexes of the first and third compound semiconductor layers.
[0023]
The semiconductor optical device according to the present invention can further include a substrate on which the first to third compound semiconductor layers are mounted. The substrate can be a GaAs substrate or a Si substrate.
[0024]
A semiconductor optical device according to the present invention includes a first conductivity type semiconductor portion, a second conductivity type semiconductor portion, a semiconductor substrate having a pair of surfaces, a first electrode, a second electrode, and a third compound semiconductor layer. Can be further provided. On one surface of the pair of surfaces, a first conductivity type semiconductor portion, a second conductivity type semiconductor portion, and first to third compound semiconductor layers are provided. A second electrode is provided on the other surface of the pair of surfaces. In the present invention, the semiconductor optical device can constitute a semiconductor optical amplification element. In the present invention, the semiconductor optical device can constitute a semiconductor laser. Furthermore, in the present invention, the semiconductor optical device can constitute a semiconductor optical modulation element.
[0025]
The quantum well structure may be either an MQW structure or an SQW structure. By combining the first to third compound semiconductor layers, various quantum well structures having steep semiconductor junctions can be realized.
[0026]
  Yet another aspect of the present invention relates to a method of manufacturing a semiconductor optical device, the method comprising: (a) forming a first conductivity type GaInP cladding layer on a first conductivity type GaAs substrate; (B) forming a quantum well structure including a well layer and a barrier layer on the GaInP cladding layer; and (c) forming a second conductivity type GaInP cladding layer on the quantum well structure. . The well layer is made of a GaInNAsP semiconductor, and the barrier layer is,It is composed of either a GaNPAs semiconductor or an AlGaInAsP semiconductor. According to these steps, a quantum well structure having a steep semiconductor junction can be produced. The barrier layer is preferably composed of a GaNPAs semiconductor. The barrier layer is preferably made of a GaPAs semiconductor. Furthermore, the barrier layer is preferably made of an AlGaInAsP semiconductor.
[0027]
The above and other objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments of the present invention, which proceeds with reference to the accompanying drawings.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The knowledge of the present invention can be easily understood by considering the following detailed description with reference to the accompanying drawings shown as examples. Subsequently, embodiments of the semiconductor optical device of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals.
[0029]
Subsequently, a semiconductor light emitting element will be described as an example of a semiconductor optical device. Examples of the semiconductor light emitting element include a semiconductor laser element and a semiconductor optical amplifying element. The same structure as this semiconductor light emitting element can be applied to a semiconductor modulation element such as an electroabsorption modulation element.
[0030]
(First embodiment)
FIG. 1 is a perspective view showing a semiconductor light emitting device. The semiconductor light emitting device 1a includes a substrate 3, a first conductivity type semiconductor layer 5, a compound semiconductor portion 7a, a first second conductivity type semiconductor layer 9, a current blocking layer 11, and a second second conductivity type. A semiconductor layer 13, a third second conductivity type semiconductor layer 15, a first electrode 17, and a second electrode 19 are provided. The substrate 3 has a pair of surfaces 3a and 3b. One surface 3a faces the other surface 3b. The surface 3 a of the substrate 3 includes a first conductive semiconductor layer 5, a compound semiconductor portion 7 a, a first second conductive semiconductor layer 9, a current blocking layer 11, and a second second conductive semiconductor layer 13. And the third second conductivity type semiconductor layer 15. The compound semiconductor portion 7 a is provided between the first conductivity type semiconductor layer 5 and the second conductivity type semiconductor layer 9. A first electrode 17 is provided on the third second conductivity type semiconductor layer 15. A second electrode 19 is provided on the surface 3 b of the substrate 3.
[0031]
The current block layer 11 is provided on the second conductivity type semiconductor layer 9. The current block layer 11 has an opening 11a. The light emitting region of the compound semiconductor portion 7a appears in the opening 11a. In the embodiment shown in FIG. 1, the semiconductor light emitting device 1a is provided along an axis extending from one end surface 21a to the other end surface 21b. A compound semiconductor portion 7a appears in the opening 11a. The current blocking layer 11 acts as a barrier against carriers (either electrons or holes) from the second conductivity type semiconductor layer 15. Due to this barrier, the carriers pass through the opening 11a and reach the compound semiconductor portion 7a. That is, the opening 11a defines a region of the compound semiconductor portion 7a into which carriers are injected.
[0032]
The second conductivity type semiconductor layer 13 is provided on the light emitting region of the compound semiconductor portion 7 a and on the current blocking layer 11. Therefore, the opening 11a is filled with the second conductivity type semiconductor layer 13, and the second conductivity type semiconductor layer 13 provides a path from the second conductivity type semiconductor layer 15 to the compound semiconductor portion 7a.
[0033]
The second conductivity type semiconductor layer 15 is formed of a semiconductor to which a relatively high concentration of impurities is added and the band gap is small. Thereby, it is easy to obtain ohmic contact with the electrode 17. The second conductivity type semiconductor layer 15 functions as a contact layer.
[0034]
The electrode 17 is provided on the second conductivity type semiconductor layer 15. The electrode 17 is provided so as to provide carriers in the region of the opening 11 a of the current blocking layer 11. That is, the electrode 17 is located on the opening 11a, and in the embodiment shown in FIG. 1, is provided along the axis extending from the one end surface 21a to the other end surface 21b of the semiconductor light emitting element 1a. The electrode 19 is provided on the surface 3 b of the substrate 3.
[0035]
FIG. 2A shows the structure of the compound semiconductor portion. FIG. 2B is a diagram showing a band diagram of the compound semiconductor portion. Referring to FIG. 2A, the compound semiconductor portion 7a includes compound semiconductor layers 23a and 23b and compound semiconductor layers 24a to 24c. The compound semiconductor layer 23a is provided between the compound semiconductor layer 24a and the compound semiconductor layer 24b. The compound semiconductor layer 23b is provided between the compound semiconductor layer 24a and the compound semiconductor layer 24c. The compound semiconductor layers 23a and 23b are made of a semiconductor containing a gallium element, an indium element, a nitrogen element, an arsenic element, or a phosphorus element, such as a GaInNAsP semiconductor. Each of the compound semiconductor layers 24a to 24c is composed of a semiconductor containing one or more kinds of group III elements, arsenic elements, and phosphorus elements, such as GaInAsP semiconductors. In the semiconductor optical device 1a, both the compound semiconductor layers 24a to 24c and the compound semiconductor layers 23a and 23b contain an arsenic element and a phosphorus element. Therefore, in the junction between the compound semiconductor layers 24a to 24c and the compound semiconductor layers 23a and 23b, phosphorus Substitution of atoms (P) and arsenic atoms (As) is difficult to occur. Therefore, it is difficult to form a transition layer at the interface between these semiconductor layers. Therefore, a semiconductor junction having a sharp composition change at the interface can be obtained.
[0036]
Referring to FIG. 2B, the compound semiconductor portion 7a has a quantum well structure 27a. In the quantum well structure 27a, the band gap ΔE of the compound semiconductor layer 24b_B1Is the band gap ΔE of the compound semiconductor layers 23a and 23b._WThe band gap ΔE of the compound semiconductor layers 24a and 24c is smaller._B2, △ E_B3Is the band gap ΔE of the compound semiconductor layers 23a, 23b._WSmaller than. The compound semiconductor layers 23a and 23b function as well layers. The compound semiconductor layer 24b functions as a barrier layer. The compound semiconductor layers 24a and 24c function as an optical confinement layer or a barrier layer. Therefore, carriers (electrons and holes) from the first conductive type semiconductor layer 5 and the first second conductive type semiconductor layer 9 are confined in the quantum well structure 27a.
[0037]
2A, the quantum well structure 27a is provided between the first conductivity type semiconductor layer 5 and the first second conductivity type semiconductor layer 9. Referring to FIG. 2B, the refractive index n of the first conductivity type semiconductor layer 5 is obtained._CL1And the refractive index n of the second conductivity type semiconductor layer 9_CL2Is the refractive index n of the semiconductor layer in the quantum well structure 27a_B1, N_W, N_C2, N_C3Smaller than any of the above. Therefore, when the light generated in the quantum well structure 27a propagates along the quantum well structure 27, it is confined in a region between the first conductivity type semiconductor layer 5 and the first second conductivity type semiconductor layer 9. It is done. At this time, the first conductive semiconductor layer 5 and the second conductive semiconductor layer 9 can function as a cladding layer.
[0038]
Although FIG. 2A exemplarily shows a quantum well structure having a specific number of well layers and barrier layers, in the semiconductor optical device 1a, the quantum well structure 27a includes any number of well layers and It can be either an MQW structure with a barrier layer or an SQW structure. In these quantum well structures, a sharp semiconductor junction is obtained.
[0039]
Examples of the semiconductor material included in the semiconductor light emitting element 1a are shown below.
Substrate 3: n-type GaAs substrate
First conductivity type semiconductor layer 5:
n-type GaInP semiconductor,
Thickness 1.5 micrometers, carrier concentration 7 × 10¹⁷cm^-3
Compound semiconductor layers 23a and 23b:
Undoped Ga_0.86In_0.14N_0.04As_0.95P_0.01semiconductor
10 nanometers thick,
Compound semiconductor layers 24a-24c:
Undoped Ga_0.78In_0.22As_0.55P_0.45semiconductor
10 nanometers thick,
Second conductivity type semiconductor layer 9:
p-type GaInP semiconductor,
Thickness 1.5 micrometers, carrier concentration 7 × 10¹⁷cm^-3
Current blocking layer 11:
p-type AlGaInP semiconductor,
0.5 micrometer thick, carrier concentration 7 × 10¹⁷cm^-3
Second conductivity type semiconductor layer 13:
p-type GaInP semiconductor,
Thickness 1.0 micrometer, carrier concentration 7 × 10¹⁷cm^-3
Second conductivity type semiconductor layer 15:
p-type GaAs semiconductor,
200 nanometers thick, carrier concentration 1 × 10¹⁹cm^-3
In a preferred embodiment, a silicon substrate having a GaAs semiconductor layer on its main surface or a GaAs substrate can be used as the substrate 3. In this case, the compositions of the semiconductor layers 23a, 23b, 24a to 24c of the compound semiconductor portion 7a are determined so as to lattice match with the GaAs semiconductor. Here, the lattice matching of the semiconductor A with the semiconductor B means that the lattice parameter_A-A_B) / A_BIs in the range of −0.5 percent or more and +0.5 percent or less.
[0040]
Since the compound semiconductor layers 23a and 23b are made of a semiconductor containing a gallium element, an indium element, a nitrogen element, an arsenic element, and a phosphorus element, the range in which the band gap and the lattice constant can be changed independently is wide.
[0041]
Although the semiconductor light emitting device has been described with reference to FIGS. 1, 2A and 2B, when the semiconductor light emitting device is a Fabry-Perot type semiconductor laser device, the one end surface 21a and the other end surface 21b are formed. The reflectance is determined so that the one end face 21a and the other end face 21b constitute an optical resonator of the semiconductor laser element. When the semiconductor light emitting device is a DFB type semiconductor laser device, a diffraction grating 53 is provided on the substrate 3 so as to be optically coupled to the compound semiconductor portion 7a. When the semiconductor light emitting element is a semiconductor optical amplifying element, the reflectance of the one end face 21a is determined to be a very small value, for example, 1% or less, and the reflectance of the other end face 21b is one end face 21a. It is determined to be relatively larger than the reflectance. In these semiconductor light emitting devices, the compound semiconductor portion functions as an active layer that generates light in response to injected carriers. In the semiconductor light emitting device, the structure of the active layer is configured such that the photoluminescence spectrum of the compound semiconductor portion includes a desired emission wavelength.
[0042]
The structure of the semiconductor optical device shown in FIG. 1, FIG. 2 (a) and FIG. 2 (b) can also be used as a semiconductor modulation element such as an electroabsorption type modulation element. The semiconductor modulation element receives light at one end surface 21a and emits the modulated light from the other end surface. In these semiconductor modulation elements, the compound semiconductor portion acts as an active layer that modulates incident light in response to an applied electric field. In the semiconductor modulation element, the structure of the active layer is configured such that the photoluminescence wavelength of the compound semiconductor portion is slightly different from the wavelength of incident light.
[0043]
From these semiconductor optical devices, the light L as shown in FIG._aIs provided.
[0044]
In a semiconductor optical device comprising an optical confinement layer (barrier layer) composed of a GaAs semiconductor and a GaInP semiconductor layer adjacent to the optical confinement layer, arsenic atoms and phosphorus atoms are present at the interface between the GaInP semiconductor layer and the GaAs semiconductor layer. Substitution may occur. In the embodiment, an n-type GaInP semiconductor layer is used as the first conductive type semiconductor layer 5, and a p-type GaInP semiconductor layer is used as the second conductive type semiconductor layer 9. The first conductivity type semiconductor layer 5 uses a semiconductor layer containing phosphorus element, and the optical confinement layer (barrier layer) uses a semiconductor layer containing phosphorus element and arsenic element. According to experiments conducted by the inventors, the substitution of arsenic atoms and phosphorus atoms is suppressed even at the interface between the first conductivity type semiconductor layer 5 and the optical confinement layer, and a good quality interface is obtained. It has become clear.
[0045]
Further, according to the experiment by the inventors, it has been clarified that carrier recombination is suppressed on the surface of the semiconductor layer constituting the compound semiconductor portion 7a. The inventors consider that in the semiconductor optical device 1a, the compound semiconductor layers 23a, 23b, and 24a to 24c contain a phosphorus (P) element, so that carrier recombination is suppressed.
[0046]
In a preferred semiconductor light emitting device, the band gaps of the first and third compound semiconductor layers are preferably larger than the band gaps of the GaInNAsP semiconductor and the GaAs semiconductor. Due to the larger band gap, the ability of the first and third compound semiconductor layers to confine carriers in the second compound semiconductor layer is improved. As a result, a semiconductor optical device with less temperature dependence is obtained. Each of the first and third compound semiconductor layers is preferably substantially lattice matched to the GaAs semiconductor. This semiconductor optical device can be obtained by using, for example, an AlGaInAsP semiconductor as each of the first and third compound semiconductor layers. Here, the fact that the semiconductor A substantially lattice matches with the semiconductor B indicates that the lattice parameter (a_A-A_B) / A_BIs in the range of −0.5 percent or more and +0.5 percent or less.
[0047]
(Second embodiment)
Subsequently, a semiconductor light emitting device according to another embodiment will be described. Each of FIG. 3A to FIG. 3D is a drawing showing a strained quantum well structure. These quantum well structures contain strain. 3A to 3D, the tip of the arrow indicates inward (→ ←) indicates compression strain, and the tip of the arrow indicates outward (← →) indicates tensile strain. The length of the arrow indicates the magnitude of the distortion. In the semiconductor optical devices 1b to 1e, the first conductivity type semiconductor layer 5 and the second conductivity type semiconductor layer 9 are lattice-matched to the GaAs semiconductor.
[0048]
FIG. 3A shows the semiconductor optical device 1b. In the semiconductor optical device 1b, the compound semiconductor portion 7b is provided such that the compound semiconductor layers 29a, 29b, and 31a to 31c constitute the quantum well structure 27b. In the quantum well structure 7b, the compound semiconductor layers 29a and 29b constitute a well layer, and the compound semiconductor layers 31a to 31c constitute a barrier layer. The composition of the group III element, the arsenic element, and the phosphorus element in the compound semiconductor layers 31a to 31c is determined so that each of the compound semiconductor layers 31a to 31c has a tensile strain. The composition of gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the compound semiconductor layers 29a and 29b is determined so that the compound semiconductor layers 29a and 29b have compressive strain. In the quantum well structure 27b, the magnitude of the compressive strain is larger than the magnitude of the tensile strain. This quantum well structure has an advantage that the number of well layers and barrier layers and the limitation due to strain stress on the thickness can be relaxed. The quantum well structure 27b can be realized by a combination of a GaInNAsP semiconductor and a GaNPAs semiconductor, for example. For example, the composition of the GaInNAsP semiconductor is Ga_0.7In_0.3N_0.017As_0.982P_0.001It is.
[0049]
FIG. 3B shows the semiconductor optical device 1c. In the semiconductor optical device 1c, the compound semiconductor portion 7c is provided such that the compound semiconductor layers 33a, 33b, and 35a to 35c constitute the quantum well structure 27c. In the quantum well structure 27c, the compound semiconductor layers 33a and 33b constitute a well layer and the compound semiconductor layers 35a to 35c constitute a barrier layer. The composition of the group III element, the arsenic element, and the phosphorus element in the compound semiconductor layers 35a to 35c is determined so that each of the compound semiconductor layers 35a to 35c has tensile strain. The composition of gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the compound semiconductor layers 33a and 33b is determined so that the compound semiconductor layers 33a and 33b have compressive strain. In the quantum well structure 27c, the magnitude of the compressive strain is smaller than the magnitude of the tensile strain. This quantum well structure has an advantage that the number of well layers and barrier layers and the limitation due to strain stress on the thickness can be relaxed. The quantum well structure 27c can be realized by a combination of a GaInNAsP semiconductor and a GaNPAs semiconductor. For example, the composition of the GaInNAsP semiconductor is Ga_0.7In_0.3N_0.017As_0.982P_0.001It is.
[0050]
FIG. 3C shows the semiconductor optical device 1d. In the semiconductor optical device 1d, the compound semiconductor portion 7d is provided such that the compound semiconductor layers 37a, 37b, and 39a to 39c constitute the quantum well structure 27d. In the quantum well structure 7d, the compound semiconductor layers 37a and 37b constitute a well layer, and the compound semiconductor layers 39a to 39c constitute a barrier layer. The composition of the group III element, the arsenic element, and the phosphorus element in the compound semiconductor layers 39a to 39c is determined so that each of the compound semiconductor layers 39a to 39c has a compressive strain. The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the compound semiconductor layers 37a and 37b is determined so that the compound semiconductor layers 37a and 37b have tensile strain. In the quantum well structure 27d, the compositions of both semiconductor layers are determined so that the magnitude of the compressive strain is approximately equal to the magnitude of the tensile strain. The quantum well structure 27d can be realized by, for example, a combination of a GaInNAsP semiconductor and a GaInAsP semiconductor. The quantum well structure 27d has the following advantages. Since the distortion of the entire quantum well active layer crystal is compensated, the crystal quality is hardly deteriorated and the reliability of the optical device is improved. In addition, since the well layer has tensile strain, it is easy to increase the wavelength and the light emission efficiency can be improved. Furthermore, since the distortion of the whole quantum well active layer crystal is compensated, there are no restrictions on the number and thickness of the well layers and the barrier layers.
[0051]
FIG. 3D shows the semiconductor optical device 1e. In the semiconductor optical device 1e, the compound semiconductor portion 7e is provided so that the compound semiconductor layers 41a, 41b, and 43a to 43c constitute the quantum well structure 27e. In the quantum well structure 7e, the compound semiconductor layers 41a and 41b constitute a well layer, and the compound semiconductor layers 43a to 43c constitute a barrier layer. The composition of the group III element, the arsenic element, and the phosphorus element in the compound semiconductor layers 43a to 43c is determined so that each of the compound semiconductor layers 43a to 43c has a tensile strain. The composition of gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the compound semiconductor layers 41a and 41b is determined so that the compound semiconductor layers 41a and 41b have compressive strain. In the quantum well structure 27d, the compositions of both semiconductor layers are determined so that the magnitude of the compressive strain is approximately equal to the magnitude of the tensile strain. The quantum well structure 27e can be realized by a combination of a GaInNAsP semiconductor and a GaNPAs semiconductor, for example. The quantum well structure 27e has the following advantages. Since the distortion of the entire quantum well active layer crystal is compensated, the crystal quality is hardly deteriorated and the reliability of the optical device is improved. In addition, since the well layer has a compressive strain, the wavelength is not easily shortened and the light emission efficiency can be improved. Furthermore, since the distortion of the whole quantum well active layer crystal is compensated, there are no restrictions on the number and thickness of the well layers and the barrier layers.
[0052]
In the quantum well structures 7b and 7c, the strain remains in the quantum well structure without being canceled as a whole. Depending on the strain, the oscillation mode of the semiconductor laser element varies. For example, in a compressive strain quantum well structure, the semiconductor laser element oscillates in a TE mode. In the tensile strained quantum well structure, the semiconductor laser element oscillates in the TM mode.
[0053]
In the quantum well structures 27d and 27e, since the strain cancels out as a whole of the quantum well structure, the number of well layers and barrier layers is not limited due to the strained quantum well structure. Therefore, a large gain can be obtained as a semiconductor light emitting device. In addition, the temperature characteristics of the semiconductor light emitting device are improved. Furthermore, the semiconductor light emitting device can be operated at a higher temperature and a higher output can be obtained.
[0054]
(Third embodiment)
Subsequently, a semiconductor light emitting device according to still another embodiment will be described. 4 (a) and 4 (b) are diagrams schematically showing crystal lattices of main semiconductor layers constituting a semiconductor optical device. In the following description, an embodiment in which the substrate 3 is a semiconductor substrate will be described.
[0055]
FIG. 4A shows a semiconductor 3c for a semiconductor substrate such as a GaAs semiconductor substrate, a semiconductor material 45 for a well layer of a quantum well structure, and a semiconductor material 47 for a barrier layer. The semiconductor material 3c has a lattice constant d₀have. The semiconductor material 45 has a lattice constant d₁have. The semiconductor 47 has a lattice constant d₂have. Lattice constant d₀Is the lattice constant d₁Larger, lattice constant d₂Smaller than.
[0056]
FIG. 4B shows a semiconductor 3c for a semiconductor substrate such as a GaAs semiconductor substrate, a semiconductor 49 for a well layer of a quantum well structure, and a semiconductor 51 for a barrier layer. The semiconductor material 3c has a lattice constant d₀have. The semiconductor material 49 has a lattice constant d._Threehave. The semiconductor material 51 has a lattice constant d_Fourhave. Lattice constant d₀Is the lattice constant d_FourLarger, lattice constant d_ThreeSmaller than.
[0057]
The quantum well structure has a well layer (compound semiconductor layers 23a and 23b in FIG. 2) composed of a semiconductor material 45 (or semiconductor material 49) and a barrier layer (FIG. 2) composed of a semiconductor material 47 (or semiconductor material 51). Compound semiconductor layers 24a to 24c). The first conductive semiconductor layer (reference numeral 5 in FIG. 1) and the second conductive semiconductor layer (reference numeral 9 in FIG. 1) are lattice-matched to the GaAs semiconductor. However, the composition of the group III element, arsenic element, and phosphorus element in the first and second compound semiconductor layers is such that the semiconductor constituting each of the compound semiconductor layers (compound semiconductor layers 24a to 24c in FIG. 2) is a GaAs semiconductor. It is determined not to match the lattice. The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the compound semiconductor layer (compound semiconductor layers 23a and 23b in FIG. 2) is such that the semiconductor constituting the third compound semiconductor layer is lattice matched to the GaAs semiconductor. Decided not to.
[0058]
In a preferred embodiment, when the barrier layer and the well layer have substantially the same thickness, the lattice constant d of the semiconductor material constituting the barrier layer_AAnd lattice constant d of the semiconductor material constituting the well layer_BArithmetic mean of_AV= (D_A+ D_B) Is the lattice constant d of the GaAs semiconductor._GaAsIs substantially the same as Here, the substantial coincidence is −0.005 ≦ (d_AV-D_GaAs) / D_GaAsIt means ≦ + 0.005. The strain is substantially canceled as a whole in the quantum well structure, and the number of well layers and barrier layers is not restricted due to the strain in the quantum well structure.
[0059]
In a preferred semiconductor optical device, the barrier layer is composed of a GaNPAs semiconductor. The well layer is composed of a GaInNAsP semiconductor, and in this combination, the quantum level in the GaInNAsP well layer is shifted with low energy compared to a quantum well structure in which the barrier layer is composed of a GaAs semiconductor. This makes it possible to use a 1.5 micrometer wavelength band that cannot be realized by the quantum well structure of GaInNAsP well layer / GaAs barrier layer. The 1.5 micrometer wavelength band is an important band in the field of optical communications.
[0060]
In another suitable semiconductor optical device, the barrier layer is composed of a GaPAs semiconductor. The well layer is composed of a GaInNAsP semiconductor. The band gap of the GaPAs semiconductor is larger than that of the GaAs semiconductor. In the GaPAs semiconductor, carriers are confined in the quantum well structure. Therefore, the temperature characteristics of the semiconductor optical device are improved.
[0061]
(Fourth embodiment)
FIG. 5 is a perspective view showing a semiconductor light emitting device according to another embodiment. The semiconductor light emitting device 1f has a structure of a vertical optical resonator surface emitting laser device. The semiconductor light emitting device 1f includes a substrate 60, a first semiconductor portion 62, a first conductivity type semiconductor layer 64, a compound semiconductor portion 66, a fourth second conductivity type semiconductor layer 68, and a fifth second. Conductive semiconductor layer 70, current blocking layer 72, fifth second conductive semiconductor layer 74, second semiconductor portion 76, sixth second conductive semiconductor layer 78, and first electrode 80. And a second electrode 82. Examples of the substrate 60 include semiconductor substrates such as a GaAs substrate and a silicon substrate. The substrate 60 has a pair of surfaces 60a and 60b. One surface 60a faces the other surface 60b. The surface 60a of the substrate 60 includes a first semiconductor part 62, a first conductive semiconductor layer 64, a compound semiconductor part 66, a fourth second conductive semiconductor layer 68, and a fifth second conductive semiconductor. The layer 70, the current blocking layer 72, the fifth second conductivity type semiconductor layer 74, the second semiconductor portion 76, and the sixth second conductivity type semiconductor layer 78 are mounted. The first semiconductor unit 62 and the second semiconductor unit 76 constitute an optical resonator.
[0062]
The compound semiconductor unit 66 is located between the first semiconductor unit 62 and the second semiconductor unit 76. The compound semiconductor portion 66 is provided between the first conductivity type semiconductor layer 64 and the second conductivity type semiconductor layer 68. The compound semiconductor portion 66 has any of the forms shown in FIGS. 2A, 2B, 3A to 3D, 4A, and 4B. be able to. The compound semiconductor unit 66 is provided so as to generate light in a predetermined wavelength band.
[0063]
The main surface of the second conductivity type semiconductor layer 68 has a first region 68a and a second region 68b. The first region 68a is provided so as to surround the periphery of the second region 68b. A fourth second conductive semiconductor layer 70, a current blocking layer 72, and a fifth second conductive semiconductor layer 74 are provided on the second region 68b.
[0064]
The main surface of the second conductivity type semiconductor layer 74 has a first region 74a and a second region 74b. The first region 74a is provided so as to surround the periphery of the second region 74b. A second semiconductor portion 76 is provided on the second region 74b. The area of the second region 74b is smaller than the area of the second region 68b.
[0065]
The current blocking layer 72 is provided on the fifth second conductivity type semiconductor layer 70, and has an opening 72 a on the light emitting region of the compound semiconductor portion 66. The main surface of the second conductivity type semiconductor layer 70 has a first region 70a and a second region 70b. The first region 70a is provided so as to surround the second region 70b. A current blocking layer 72 is provided on the first region 70a. On the second region 70b, an opening 72a of the current blocking layer 72 is provided. The second conductivity type semiconductor layer 70 appears in the opening 72a. A current path semiconductor layer 73 is provided on the second conductivity type semiconductor layer 70. The current path semiconductor layer 73 is located in the opening 72 a, and the second conductivity type semiconductor layer 74 is provided on the current block layer 72 and the current path semiconductor layer 73. The current blocking layer 72 acts as a barrier against carriers (either electrons or holes) from the second conductivity type semiconductor layer 74. Due to this barrier, the carriers pass through the opening 72 a and reach the compound semiconductor portion 66. That is, the opening 72a defines a region of the compound semiconductor portion 66 into which carriers are injected. The current blocking layer selectively oxidizes a part of the AlAs semiconductor layer having the second conductivity type from the periphery of the mesa toward the inside of the mesa.₂O_ThreeIt is formed by forming an insulating layer in a donut shape. As a result, the opening 72a of the current blocking layer is formed as an AlAs semiconductor layer having the second conductivity type that can be electrically conducted.
[0066]
The second conductivity type semiconductor layer 74 is provided on the second conductivity type semiconductor unit 70 and the current blocking layer 72. The opening 72 a may be filled with the second conductivity type semiconductor layer 74. At this time, the second conductivity type semiconductor layer 74 is routed from the second semiconductor portion 76 to the second conductivity type semiconductor layer 70. Is provided.
[0067]
The second conductivity type semiconductor layer 78 is formed of a semiconductor to which a relatively high concentration of impurities is added and the band gap is small. Therefore, it is easy to obtain ohmic contact with the electrode 17. The second conductivity type semiconductor layer 78 functions as a contact layer.
[0068]
The electrode 80 is provided on the second conductivity type semiconductor layer 78. The electrode 80 is provided so that a carrier can be provided to the second semiconductor portion 76. That is, the electrode 80 is located on the opening 72a. A second electrode 82 is provided on the surface 60 b of the substrate 60.
[0069]
FIG. 6A shows the structure of the first semiconductor portion. The first semiconductor unit 62 includes a plurality of semiconductor layers 62a and a plurality of semiconductor layers 62b. The semiconductor layers 62a and the semiconductor layers 62b are alternately arranged. The refractive index of the semiconductor layer 62a is different from the refractive index of the semiconductor layer 62b. Therefore, the semiconductor unit 62 constitutes a diffraction grating.
[0070]
FIG. 6B shows the structure of the second semiconductor portion. The second semiconductor unit 76 includes a plurality of semiconductor layers 76a and a plurality of semiconductor layers 76b. The semiconductor layers 76a and the semiconductor layers 76b are alternately arranged. The refractive index of the semiconductor layer 76a is different from the refractive index of the semiconductor layer 76b. Therefore, the semiconductor unit 76 constitutes a diffraction grating.
[0071]
The semiconductor light emitting element 1f is a light L having a predetermined wavelength within a wavelength band in which the reflection spectrum of the diffraction grating of the semiconductor unit 62, the reflection spectrum of the diffraction grating of the semiconductor unit 76, and the emission spectrum of the compound semiconductor unit 66 overlap._bCan be generated.
[0072]
Examples of the semiconductor material included in the semiconductor light emitting device 1f are shown below.
Substrate 60: n-type GaAs substrate
First semiconductor part 62;
n-type AlAs semiconductor / n-type GaAs semiconductor 22.5 periods
115 nm thickness / 90 nm thickness,
Carrier concentration 1 × 10¹⁸cm^-3/ 1 × 10¹⁸cm^-3
Semiconductor layer 64:
Undoped Al_0.5Ga_0.5As semiconductor,
175 nanometer thickness
Compound semiconductor part 66:
Undoped GaInNAsP semiconductor / Undoped GaInAsP semiconductor
10 nanometers thick / 10 nanometers thick
Semiconductor layer 68:
Undoped Al_0.5Ga_0.5As semiconductor,
175 nanometer thickness
Second conductivity type semiconductor layer 70:
p-type GaAs semiconductor,
30 nanometers thick, carrier concentration 7 × 10¹⁷cm^-3
Current blocking layer 72:
p-type Al₂O_Three,
30 nanometers thick
Current path semiconductor layer 73:
p-type AlAs semiconductor,
30 nanometers thick,
Second conductivity type semiconductor layer 74:
p-type GaAs semiconductor,
30 nanometers thick, carrier concentration 7 × 10¹⁷cm^-3
Second semiconductor unit 76:
p-type Al_0.1Ga_0.9As semiconductor / n-type GaAs semiconductor 20 periods
Thickness 110nm / 90nm,
Carrier concentration 7 × 10¹⁷cm^-3/ 7 × 10¹⁷cm^-3
Contact layer 78;
p-type GaAs semiconductor
60 nanometers thick, carrier concentration 1 × 10¹⁹cm^-3
In a preferred embodiment, a silicon substrate having a GaAs semiconductor layer on its main surface or a GaAs substrate can be used as the substrate 3.
[0073]
(Fifth embodiment)
Subsequently, a method for manufacturing a semiconductor optical device will be described. As shown in FIG. 7A, a GaAs semiconductor substrate 90 is prepared. The GaAs semiconductor substrate 90 has a pair of surfaces 90a and 90b. The front surface 90a faces the back surface 90b.
[0074]
Referring to FIG. 7B, an n-type III-V group compound semiconductor layer 92 is formed on the main surface 90a of the n-type GaAs semiconductor substrate 90. The compound semiconductor layer 92 is composed of an n-type GaInP semiconductor layer lattice-matched to a GaAs semiconductor. Next, the compound semiconductor portion 94 is formed on the n-type compound semiconductor layer 92. The n-type compound semiconductor layer 92 and the compound semiconductor portion 94 are epitaxially grown by, for example, a metal organic chemical vapor deposition method (OMVPE method) or a molecular beam epitaxy method (MBE method).
[0075]
The formation of the compound semiconductor portion 94 will be described with reference to FIGS. 8 (a) to 8 (d). The compound semiconductor unit 94 includes an undoped GaInNAsP semiconductor layer and an undoped GaInAsP semiconductor layer. As shown in FIG. 8A, an undoped GaInAsP semiconductor layer 94a is grown on the n-type GaInP semiconductor layer 92. At the interface between the GaInP semiconductor layer 92 and the GaInAsP semiconductor layer 94a, substitution between adjacent (P) and arsenic (As) is suppressed, so that a sharp junction can be obtained. Next, as shown in FIG. 8B, an undoped GaInNAsP semiconductor layer 94b is grown on the GaInAsP semiconductor layer 94a. Since the substitution of adjacent (P) and arsenic (As) is suppressed at the interface between the GaInAsP semiconductor layer 94a and the GaInNAsP semiconductor layer 94b, a steep junction can be obtained. This growth step is repeated until the desired semiconductor layer stack is obtained. Thereby, the compound semiconductor part 94 is obtained.
[0076]
However, when the compound semiconductor portion is composed of an undoped GaInNAsP semiconductor layer and an undoped GaAs semiconductor layer, an undoped GaAs semiconductor layer 95a is grown on the n-type GaInP semiconductor layer 92 as shown in FIG. . Since the substitution of phosphorus (P) and arsenic (As) occurs at the interface between the GaInP semiconductor layer 92 and the GaAs semiconductor layer 95a, a transition layer 97a is formed between the GaInP semiconductor layer 92 and the GaAs semiconductor layer 95a. . Next, as shown in FIG. 8D, an undoped GaInNAsP semiconductor layer 95b is grown on the GaAs semiconductor layer 95a. Since substitution of phosphorus (P) and arsenic (As) occurs at the interface between the GaAs semiconductor layer 95a and the GaInNAsP semiconductor layer 95b, the transition layer 97b is formed between the GaInP semiconductor layer and the GaInAsP semiconductor layer. The composition and thickness of the transition layers 97a and 97b are not controlled.
[0077]
Subsequently, as shown in FIG. 9A, a p-type III-V group compound semiconductor layer 96 composed of a p-type GaInP semiconductor layer lattice-matched to a GaAs semiconductor is epitaxially grown on the compound semiconductor portion 94. Next, an n-type compound semiconductor layer 98 such as an AlGaInP semiconductor layer for a current blocking layer is epitaxially grown on the p-type compound semiconductor layer 96.
[0078]
As shown in FIG. 9B, the mask layer 100 is formed on the p-type compound semiconductor layer 98. The mask layer 100 includes an opening 100a for defining a current passage region. After the mask layer 100 is formed, the p-type compound semiconductor layer 98 is selectively etched with respect to the p-type compound semiconductor layer 96 using a phosphoric acid-based etchant to form a current blocking layer 98a having an opening 98b. To do. The opening 98b extends along a predetermined axis. In the opening 98b, the p-type compound semiconductor layer 96 is exposed.
[0079]
As shown in FIG. 10A, a III-V group compound semiconductor layer 102 such as a p-type GaInP semiconductor layer is epitaxially grown on the current blocking layer 98 a and the p-type compound semiconductor layer 96. Next, the contact layer 104 is epitaxially grown on the III-V compound semiconductor layer 102.
[0080]
An anode electrode 106 is formed on the contact layer 104. The anode electrode 106 extends in the same direction as the opening 98b of the current blocking layer 98a. On the back surface 90 b of the substrate 90, the cathode electrode 108 is formed. The semiconductor optical device 1g is obtained through these steps.
[0081]
In the semiconductor light emitting device described above, according to the knowledge of the inventors, phosphorus is added to the light emitting region and the vicinity thereof, so that the surface recombination current is reduced.
[0082]
In the semiconductor laser device in which strain (compression or tensile strain) is applied to the quantum well structure, the following laser characteristics are improved. The gain and differential gain of the semiconductor laser element can be increased, the threshold current can be decreased, the light emission efficiency can be increased, high temperature operation is possible, and the oscillation mode can be controlled.
[0083]
Various semiconductor optical devices can be obtained by combining GaInNAsP semiconductors with other III-V group compound semiconductors.
[0084]
While the principles of the invention have been illustrated and described in the preferred embodiments, it will be appreciated by those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles. For example, although a single semiconductor light emitting element has been described in the present embodiment, a semiconductor optical device can also include a plurality of semiconductor light emitting elements. The semiconductor optical device can be an optical integrated device. The optical integrated device can include a semiconductor modulation device and a semiconductor light emitting device. Moreover, although the semiconductor optical device provided with the semiconductor substrate was described in the embodiment, the present invention is not limited to this. Furthermore, in the embodiments, the semiconductor light emitting device and the semiconductor modulation device including the semiconductor substrate have been described. However, the present invention can be applied to a light receiving device such as a waveguide type semiconductor light receiving device, and is not limited thereto. In addition, the present invention is not limited to the above embodiment, and can be applied to other semiconductor materials, for example. Therefore, the present invention is not limited to the specific configuration disclosed in the present embodiment. We therefore claim all modifications and changes that come within the scope and spirit of the following claims.
[0085]
【The invention's effect】
As described above in detail, according to the present invention, there is provided a semiconductor optical device having a structure in which substitution of phosphorus atoms (P) and arsenic atoms (As) hardly occurs at the interface between two semiconductor layers, and a method for manufacturing the same. Is done.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a semiconductor light emitting device.
FIG. 2 (a) is a drawing showing the structure of a compound semiconductor portion. FIG. 2B is a diagram showing a band diagram of the compound semiconductor portion.
3 (a) to 3 (d) are drawings showing a strained quantum well structure. FIG.
FIGS. 4A and 4B are diagrams schematically showing crystal lattices of main semiconductor layers constituting a semiconductor optical device. FIGS.
FIG. 5 is a perspective view showing a semiconductor light emitting element according to another embodiment.
FIG. 6A is a drawing showing a structure of a first semiconductor portion. FIG. 6B shows the structure of the second semiconductor portion.
7 (a) and 7 (b) are drawings showing a method of manufacturing a semiconductor optical device.
FIGS. 8A and 8B are diagrams showing a procedure for growing a compound semiconductor portion of a semiconductor optical device. FIGS. FIG. 8C and FIG. 8D are drawings showing a procedure for growing a compound semiconductor portion of a semiconductor optical device.
FIG. 9A and FIG. 9B are drawings showing a method of manufacturing a semiconductor optical device.
FIGS. 10A and 10B are diagrams showing a method of manufacturing a semiconductor optical device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a, 1b ... Semiconductor light emitting element, 3 ... Substrate, 5 ... 1st conductivity type semiconductor layer, 7a ... Compound semiconductor part, 9 ... 2nd conductivity type semiconductor layer, 11 ... Current block layer, 11a ... Opening part, 13 ... 1st Two-conductivity-type semiconductor layer, 15 ... second-conductivity-type semiconductor layer, 17 ... first electrode, 19 ... second electrode, 23a, 23b, 24a-24c ... compound semiconductor layer, 60 ... substrate, 62 ... first Semiconductor part 64 ... 1st conductivity type semiconductor layer 66 ... Compound semiconductor part 68 ... 4th 2nd conductivity type semiconductor layer, 70 ... 5th 2nd conductivity type semiconductor layer, 72 ... Current block layer, 73 ... Current path semiconductor layer, 74 ... fifth second conductivity type semiconductor layer, 76 ... second semiconductor part, 78 ... sixth second conductivity type semiconductor layer, 80 ... first electrode, 82 ... second electrode ,

Claims (5)

A first compound semiconductor layer containing one or more types of Group III elements, arsenic elements, and phosphorus elements;
A second compound semiconductor layer containing a gallium element, an indium element, a nitrogen element, an arsenic element, and a phosphorus element ;
A third compound semiconductor layer containing one or more types of group III elements, arsenic elements, and phosphorus elements;
A fourth compound semiconductor layer composed of a GaInP semiconductor;
A fifth compound semiconductor layer composed of a GaInP semiconductor;
A GaAs substrate on which the first to fifth compound semiconductor layers are mounted;
The fourth compound semiconductor layer is a cladding layer;
The fifth compound semiconductor layer is a cladding layer;
The second compound semiconductor layer is composed of a GaInNAsP semiconductor,
The first and third compound semiconductor layers are composed of either a GaNPAs semiconductor or an AlGaInAsP semiconductor,
The band gap of each of the first and third compound semiconductor layers is larger than the band gaps of GaInNAsP semiconductor and GaAs semiconductor,
The first to third compound semiconductor layers form a quantum well structure in which the second compound semiconductor layer forms a well layer and the first and third compound semiconductor layers form a barrier layer. Provided,
The first to third compound semiconductor layers are semiconductor optical devices provided between the fourth compound semiconductor layer and the fifth compound semiconductor layer. A first semiconductor portion including a plurality of first conductivity type semiconductor layers provided to form a multilayer reflective film;
A second semiconductor portion including a plurality of second conductivity type semiconductor layers provided so as to form a multilayer reflective film;
The semiconductor optical device according to claim 1, wherein the first to fifth compound semiconductor layers are provided between the first semiconductor portion and the second semiconductor portion. The composition of the group III element, arsenic element, and phosphorus element in the first and third compound semiconductor layers is such that each of the first and third compound semiconductor layers has one of compressive strain and tensile strain. Has been determined as
The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the second compound semiconductor layer is determined so that the second compound semiconductor layer has the other strain of compressive strain and tensile strain. The semiconductor optical device according to claim 1, wherein the semiconductor optical device is provided. The composition of the group III element, the arsenic element, and the phosphorus element in the first and third compound semiconductor layers is such that the semiconductor constituting each of the first and third compound semiconductor layers has a lattice constant of a GaAs semiconductor. Has been determined to be inconsistent,
The composition of the gallium element, indium element, nitrogen element, arsenic element, and phosphorus element in the second compound semiconductor layer is such that the lattice constant of the semiconductor constituting the second compound semiconductor layer does not lattice match with the GaAs semiconductor. Has been determined
3. The semiconductor optical device according to claim 1, wherein an average lattice constant of the semiconductor constituting the barrier layer and the semiconductor constituting the well layer substantially coincides with the lattice constant of the GaAs semiconductor. device. Forming a first conductivity type GaInP cladding layer on a first conductivity type GaAs substrate;
Forming a quantum well structure including a well layer and a barrier layer on the GaInP cladding layer;
Forming a second conductivity type GaInP cladding layer on the quantum well structure,
The well layer is made of a GaInNAsP semiconductor,
The method for manufacturing a semiconductor optical device, wherein the barrier layer is composed of either a GaNPAs semiconductor or an AlGaInAsP semiconductor.

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