JP3606933B2 - Semiconductor laser - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a semiconductor laser, and is particularly suitable as a semiconductor laser for ranging that constitutes the eyes of a robot, a laser radar system, and the like.
[0002]
[Prior art]
In recent years, a system that measures the distance between cars using a semiconductor laser and keeps the distance between cars constant, or issues an alarm or brakes when the vehicle ahead is approached too much has been studied. Yes. In such a system, it is necessary to detect an object 100 m ahead, and a semiconductor laser is required to output light of several tens of watts by pulse drive. The structure of this high-power semiconductor laser is shown in FIG. An n-GaAs layer 22 and an n-AlGaAs cladding layer 23 are stacked on the n-GaAs substrate 21, and an active layer 24, a p-AlGaAs cladding layer 25, and a p-GaAs layer 26 are stacked in a mesa shape thereon. . Here, an active layer is a layer that converts injected carriers by confining and recombining injected carriers. Further, an insulating film 27 and a p-type electrode 28 are formed. On the other hand, an n-type electrode 29 and an Au / Sn layer 30 are formed on the back surface of the n-GaAs substrate 21.
[0003]
In general, a high output pulse semiconductor laser of several tens of W class needs to have a stripe width of at least 100 μm or more as shown in FIG. On the other hand, the thickness of the active layer 24 needs to be about 0.1 μm for the purpose of confining carriers in a narrow region and reducing the threshold current. As described above, since the high-power pulsed semiconductor laser has a stripe width larger than the wavelength and a thickness of the active layer, light is not diffracted in the spreading direction (horizontal direction) of the active layer and active Since diffraction occurs in the thickness direction (vertical direction) of the layer, the beam shape has an elliptical shape spreading in the thickness direction (vertical direction) of the active layer, and the ellipticity ratio (the major axis of the beam cross section in FIG. 9). (H / W ratio of H to minor axis W) is about 2.5 to 3.2.
[0004]
An optical lens is used to condense the laser beam into a range having a desired divergence angle. From the viewpoint of ease of lens design and miniaturization of the system, the beam shape of the emitted laser beam is used. It is desirable that the shape be as close to a circle as possible, and an ellipticity ratio smaller than “2.5” is required.
[0005]
As a general method for obtaining a laser beam having a beam shape close to a circle, Japanese Patent Application Laid-Open No. 55-143092 discloses a low-power semiconductor laser in which a lens portion having a high refractive index is formed. However, there is a problem that a new process is required to form the lens portion in the semiconductor. Japanese Patent Laid-Open No. 4-151887 discloses a laser beam that does not require a lens portion and is capable of obtaining a laser beam having a nearly circular shape. In Japanese Patent Laid-Open No. 4-151877, in the same low-power semiconductor laser, light guide layers (confinement layers) having a lower refractive index than the active layer are formed above and below the active layer, and the width of the active layer is 0.5 μm or more , 1.5 μm or less. Here, the light guide layer is a layer that functions to confine and guide light generated in the active layer.
[0006]
[Problems to be solved by the invention]
However, the semiconductor laser disclosed in Japanese Patent Application Laid-Open No. 4-151877 is a laser having a beam shape close to a circle when used for a semiconductor laser of a low output (several tens of mW) class (stripe width; several μm to several tens of μm). Light can be obtained, but when used in a high-power pulsed semiconductor laser with a stripe width of 100 μm or more, a beam shape close to a circle is obtained by simply limiting the width of the active layer and sandwiching it between the light guide layers. It was found that it was not possible to obtain the laser beam.
[0007]
This is because, in general, in a low-power semiconductor laser (with a stripe width of less than 100 μm), the light emission start current (threshold current) changes, so that the thickness of the light guide layer cannot be made very large. Therefore, in order to change the beam shape, it is only possible to change the stripe width, change the width of the active layer, or add a carrier barrier layer on both sides of the active layer (Japanese Patent Laid-Open No. 61-79288). It was because it was thought that there was not. Since this light emission start current change was considered to occur even in a semiconductor laser having a stripe width of 100 μm or more, a high-power semiconductor laser having only an ellipticity of about 2.5 to 3.2 as described above can be obtained. It wasn't.
[0008]
Accordingly, an object of the present invention is to provide a semiconductor laser capable of obtaining a laser beam having a beam shape close to a circle in a high-power semiconductor laser having a stripe width of 100 μm or more.
[0009]
[Means for Solving the Problems]
The present inventors have found that the light confinement effect is determined by the total thickness of the light guide layer and the active layer.
[0010]
Accordingly, the invention described in claim 1 is a semiconductor laser having a stripe width of 100 μm or more, in which carriers are injected, and an active layer that generates light by recombining the injected carriers, and the active layer A light guide layer formed adjacent to the top and bottom of the layer, made of a material having a refractive index substantially lower than that of the active layer and confining the light generated in the active layer, and through the light guide layer A clad layer formed above and below the active layer and made of a material having a refractive index substantially lower than that of the light guide layer, and the total thickness of the active layer and the light guide layer is 1 The gist of the present invention is a semiconductor laser of not less than 0.5 μm and not more than 5.5 μm.
[0011]
The gist of a second aspect of the present invention is a semiconductor laser in which the thickness of the active layer in the first aspect of the invention is 0.05 μm or more and 0.15 μm or less.
The gist of the invention described in claim 3 is a semiconductor laser in which the active layer, the light guide layer, and the clad layer in the invention described in claim 1 or 2 are made of an AlGaAs-based material.
[0012]
According to a fourth aspect of the present invention, the active layer, the light guide layer, and the clad layer according to any one of the first to third aspects of the present invention are replaced with an InGaAlP-based material, an InGaAsP-based material, or an InGaAsSb-based material. The gist of the present invention is a semiconductor laser composed of any one of AlGaInN-based materials.
[0015]
The invention according to claim 5 is the first conductivity type first clad layer formed on one surface of the active layer, wherein the clad layer in the invention according to any one of claims 1 to 4 A second conductivity type second clad layer formed on the other surface of the active layer, further comprising a semiconductor substrate formed on the first clad layer side, and the first of the semiconductor substrate. The gist of the present invention is a semiconductor laser having a bottom electrode formed on the opposite side of the cladding layer and a top electrode formed on the second cladding layer and having a stripe width of 100 μm or more.
[0016]
According to a sixth aspect of the present invention, a first conductivity type semiconductor substrate having a lower surface electrode on a lower surface, and a first conductivity type first clad formed on an upper surface of the semiconductor substrate opposite to the lower surface electrode. A first light guide layer of a first conductivity type formed on the first cladding layer and made of an AlGaAs-based material having a refractive index substantially higher than that of the first cladding layer, and the first cladding layer. Is formed adjacent to the light guide layer, made of an AlGaAs-based material, has a refractive index substantially higher than that of the first light guide layer, and carriers are injected to recombine the injected carriers. An active layer for generating light in the second conductive type second light guide layer formed adjacent to the active layer and made of an AlGaAs-based material having a refractive index substantially lower than that of the active layer; Formed on the second light guide layer; A second conductivity type second cladding layer having a refractive index substantially lower than that of the light guide layer, and an upper surface electrode formed on the second cladding layer and having a stripe width of 100 μm or more, The gist of the present invention is a semiconductor laser in which the total thickness of the first light guide layer, the active layer, and the second light guide layer is 1.5 μm or more and 5.5 μm or less.
[0017]
[Action]
According to the first, fifth , and sixth aspects of the invention, when the thickness of the light guide layer is increased, the diffraction effect of light in the thickness direction (vertical direction) of the light guide layer is reduced and the beam is narrowed. Become. On the other hand, the diffraction effect in the spreading direction (horizontal direction) of the light guide layer does not change. As shown in FIG. 4, when the total thickness of the active layer and the light guide layer is 1.5 μm or more and 5.5 μm or less, the beam approaches a circular shape.
[0018]
According to the invention described in claim 2, in addition to the action of the invention described in claim 1, since the thickness of the active layer is set to 0.05 μm or more and 0.15 μm or less, carriers are limited to a narrow region of the active layer. Therefore, the threshold current does not increase and the light output does not decrease.
[0019]
According to the invention described in claim 3, in addition to the function of the invention described in claim 1 or 2, the active layer, the light guide layer, and the clad layer are made of AlGaAs-based material. Becomes smaller than “2.5”.
[0020]
According to invention of Claim 4, in addition to the effect | action of invention of any one of Claims 1-3, an active layer, a light guide layer, and a clad layer are made into InGaAlP type material, InGaAsP type material, Since the InGaAsSb material or the AlGaInN material is used, the ellipticity of the beam is smaller than “2.5”.
[0023]
【Example】
(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
[0024]
FIG. 2 is a perspective view of the high-power semiconductor laser of this embodiment, and FIG. 1 is a cross-sectional view of the high-power semiconductor laser. FIG. 3 shows an energy band diagram of a high-power semiconductor laser. This high-power semiconductor laser is pulse-driven.
[0025]
On an n-GaAs substrate 1 as a semiconductor substrate, an n-GaAs layer 2, an n-Al _0.4 Ga _0.6 As cladding layer 3 as a first cladding layer, and an n− as a first light guide layer. Al _0.2 Ga _0.8 As light guide layer 4, active layer 5 having an Al _0.2 Ga _0.8 As / GaAs multiple quantum well structure, and p-Al _0.2 Ga as a second light guide layer _{A 0.8} As light guide layer 6, a p-Al _0.4 Ga _0.6 As cladding layer 7 as a second cladding layer, and a p-GaAs layer 8 are sequentially stacked. In the active layer 5, Al _0.2 Ga _0.8 As and GaAs are alternately stacked, and five layers of Al _0.2 Ga _0.8 As and six layers of GaAs are formed. The clad layer 3, the light guide layer 4, the active layer 5, the light guide layer 6, the clad layer 7 and the GaAs layer 8 are mesa shapes. The front end face (front end face in FIG. 2) of the active layer 5 is coated with a low reflection film, and the rear end face is coated with a high reflection film.
[0026]
The thickness of the n-GaAs layer 2 is 500 nm (0.5 μm), the thickness of the n-Al _0.4 Ga _0.6 As cladding layer 3 is 1 μm, and the n-Al _0.2 Ga _0.8 As light guide layer The thickness of 4 is 0 to 2.25 μm. In the active layer 5, the thickness of one layer of Al _0.2 Ga _0.8 As is 7.5 nm (0.0075 μm), and there are five layers of Al _0.2 Ga _0.8 As. The total thickness of Al _0.2 Ga _0.8 As is 37.5 nm (= 7.5 nm × 5 layers). Further, the thickness of one layer of GaAs in the active layer 5 is 15 nm (0.015 μm), and since there are six layers of GaAs, the total thickness of GaAs is 90 nm (= 15 nm × 6 layers). Therefore, the thickness of the active layer 5 is 127.5 nm, that is, 0.1275 μm.
[0027]
The p-Al _0.2 Ga _0.8 As light guide layer 6 has a thickness of 0 to 2.25 μm, the p-Al _0.4 Ga _0.6 As cladding layer 7 has a thickness of 1 μm, and the p-GaAs layer 8. The thickness is 0.8 μm.
[0028]
In this embodiment, the thickness of the active layer 5 is 127.5 nm, and the total thickness of the active layer 5, the light guide layer 4, and the light guide layer 6 is 1.5 μm or more.
Further, the refractive index (average refractive index) of the active layer 5 is “3.6”, and the n-Al _0.2 Ga _0.8 As light guide layer 4 and the p-Al _0.2 Ga _0.8 As light are used. The refractive index of the guide layer 6 is “3.5”, and the refractive indexes of the n-Al _0.4 Ga _0.6 As cladding layer 3 and the p-Al _0.4 Ga _0.6 As cladding layer 7 are respectively “3.3”. As shown in FIG. 3, the light guide layers 4 and 6 are set so that the band gap is larger than that of the active layer 5.
[0029]
An insulating film 9 made of SiO ₂ is formed on the upper surfaces of the n-GaAs layer 2 and the mesa-shaped portion, and a window portion 13 without the insulating film 9 is formed on the upper surface of the mesa-shaped portion. Furthermore, a p-type electrode 10 as an upper surface electrode made of Cr / Au is formed thereon, and an ohmic contact is made with the p-GaAs layer 8. The width of the window 13, that is, the stripe width is 400 μm.
[0030]
An n-type electrode 11 as a bottom electrode made of AuGe / Ni / Au is formed on the back surface of the n-GaAs substrate 1 and is in ohmic contact with the n-GaAs substrate 1. Further, an Au / Sn layer 12 is formed on the surface of the n-type electrode 11, and this Au / Sn layer 12 is a bonding agent for bonding the semiconductor laser element and a Cu heat sink as a base.
[0031]
As shown in FIG. 2, the vertical and horizontal dimensions of this high-power semiconductor laser are 500 μm × 600 μm.
Next, a method for manufacturing this high-power semiconductor laser will be described.
[0032]
First, n-GaAs layer ₂ on the n-GaAs substrate _{1, n-Al 0.4 Ga 0.6} As cladding layer _{3, n-Al 0.2 Ga 0.8} As optical guide layer _{4, Al 0.2} Active layer 5 having a Ga _0.8 As / GaAs multiple quantum well structure, p-Al _0.2 Ga _0.8 As light guide layer 6, p-Al _0.4 Ga _0.6 As cladding layer 7, p- The GaAs layer 8 is sequentially deposited by MOCVD (Metal Organic Chemical Deposition). Thereafter, a mesa portion is formed by etching.
[0033]
Subsequently, an insulating film 9 made of SiO ₂ is formed on the upper surfaces of the n-GaAs layer 2 and the mesa-like portion by a plasma CVD method, and a window portion 13 is formed by opening a window by etching. Then, a p-type electrode 10 made of Cr / Au is formed on the insulating film 9 by electron beam evaporation, and heat treatment is performed at about 360 ° C. to obtain ohmic contact.
[0034]
Further, an n-type electrode 11 made of AuGe / Ni / Au is formed on the back surface of the n-GaAs substrate 1 by electron beam evaporation, and heat treatment is performed to obtain ohmic contact. Thereafter, the Au / Sn layer 12 is formed by an electron beam evaporation method. Finally, the end face is cleaved to form a semiconductor laser chip.
[0035]
By passing a pulse current between the p-type electrode 10 and the n-type electrode 11 of this laser, holes are transferred from the p-Al _0.4 Ga _0.6 As cladding layer 7 side to the n-Al _0.4 Ga. _{0. 6} Electrons are respectively injected into the active layer 5 from the As cladding layer 3 side, and light is emitted by recombination. The light emitted in this way is repeatedly reflected on the front and rear end faces of the cleavage, and is amplified and laser oscillated, and laser light is emitted from the front end face.
[0036]
In FIG. 4, the thickness of the active layer 5 is 127.5 nm, and the thicknesses of the n-Al _0.2 Ga _0.8 As light guide layer 4 and the p-Al _0.2 Ga _0.8 As light guide layer 6 are shown. The measurement result of the ellipticity of the beam (H / W in FIG. 9) when the total thickness of the active layer 5, the light guide layer 4, and the light guide layer 6 is changed by changing the height is shown. At this time, the film thickness of the light guide layer 4 and the film thickness of the light guide layer 6 are equal.
[0037]
The following can be understood from FIG. That is, the ellipticity of the beam can be made smaller than “2.5” by setting the total thickness of the active layer 5, the light guide layer 4 and the light guide layer 6 to 1.5 μm or more. Furthermore, if the total thickness of the active layer 5, the light guide layer 4 and the light guide layer 6 is selected to be around 4.5 μm, a beam with an ellipticity ratio of “1”, that is, a nearly circular shape can be obtained. This is because when the film thickness of the light guide layer is increased, the light diffraction effect is reduced in the thickness direction (vertical direction) of the light guide layer and the beam is narrowed, whereas the light guide layer is expanded. This is because the diffraction effect in the (horizontal direction) does not change. As a result, as shown in FIG. 4, the ellipticity of the beam can be controlled from about “1” to about “3”. Further, by making the total thickness of the active layer 5, the light guide layer 4 and the light guide layer 6 equal to or less than 5.5 μm, the ellipticity of the beam can be made larger than 0.4. This is nothing but the interchange of vertical and horizontal with an ellipticity ratio of 2.5.
[0038]
In FIG. 4, the hatched area indicates the elliptic ratio of the high-power semiconductor laser (semiconductor laser without the light guide layer) shown in FIG. 8, and the elliptic ratio is about 2.5 to 3.2. is there.
[0039]
Here, by setting the thickness of the active layer 5 in the vicinity of 0.1 μm (between 0.1 ± 0.05 μm), the carriers can be confined in a narrow place and the carriers can be effectively recombined. The threshold current can be lowered, and the light output can be prevented from decreasing.
[0040]
Thus, in order to make the total film thickness of the active layer 5, the light guide layer 4 and the light guide layer 6 1.5 μm or more and to make the film thickness of the active layer 5 near 0.1 μm, this embodiment Then, the total thickness of the light guide layer 4 and the light guide layer 6 is set to 1.5 μm or more.
[0041]
The n-Al _0.2 Ga _0.8 As light guide layer 4 and the p-Al _0.2 Ga _0.8 As light guide layer 6 may have the same or different film thickness.
As described above, the semiconductor laser of this example has a stripe width for a large output of 400 μm, and has the light guide layers 4 and 6 having a refractive index lower than that of the active layer 5 above and below the active layer 5, The clad layers 3 and 7 having a refractive index lower than that of the light guide layers 4 and 6 are provided above and below the active layer 5 including the guide layers 4 and 6, and the total thickness of the active layer 5 and the light guide layers 4 and 6 is included. Was 1.5 μm or more. Therefore, when the thickness of the light guide layers 4 and 6 is increased, the light diffraction effect in the thickness direction (vertical direction) of the light guide layers 4 and 6 is reduced, and the beam is narrowed. On the other hand, the diffraction effect in the spreading direction (horizontal direction) of the light guide layers 4 and 6 does not change. Thus, the beam can be made close to a circle by setting the total thickness of the active layer 5 and the light guide layers 4 and 6 to 1.5 μm or more.
[0042]
Further, since the thickness of the active layer 5 is 0.1275 μm which is in the range of 0.05 to 0.15 μm, carriers are confined only in a narrow region of the active layer 5, which also causes the threshold current to be reduced. Increase and decrease in light output can be prevented.
[0043]
Further, the active layer 5, the light guide layers 4 and 6, and the clad layers 3 and 7 are made of an AlGaAs material. Therefore, the ellipticity of the beam can be made smaller than “2.5” by setting the total thickness of the active layer 5 and the light guide layers 4 and 6 to 1.5 μm or more. In this way, it is possible to obtain a beam shape close to a circle whose beam ellipticity is smaller than “2.5” while maintaining a high output, and it becomes easy to design and manufacture a lens for collecting light. This makes it possible to manufacture a laser having a beam shape suitable for the above requirements.
[0044]
Furthermore, by using an AlGaAs-based material, a laser having an oscillation wavelength of 0.8 μm band can be obtained.
As described above, in general, in a low-power semiconductor laser (stripe width of less than 100 μm), the thickness of the light guide layer cannot be made too large due to the problem that the emission start current (threshold current) changes. In order to change the beam shape, it is only necessary to change the stripe width, change the width of the active layer, or add a carrier barrier layer on both sides of the active layer (Japanese Patent Laid-Open No. 61-79288). It was thought. Since this light emission start current change was considered to occur even in a semiconductor laser having a stripe width of 100 μm or more, a high-power semiconductor laser having only an ellipticity of about 2.5 to 3.2 as described above can be obtained. It wasn't. However, the present inventors have found that in a semiconductor laser having a stripe width of 100 μm or more, the threshold current (light emission start current) hardly changes even when the thickness of the light guide layer is changed. It has been found that the shape of the beam can be controlled by actively changing the thickness of the guide layer and the thickness of the active layer. And it discovered that the shape of a beam could be made smaller than "2.5" by making the sum total of the thickness of the optical guide layer and an active layer into 1.5 micrometers or more.
( Reference example)
Next, a reference example will be described focusing on differences from the first embodiment.
[0045]
As shown in FIGS. 5 and 6, the high-power semiconductor laser of this reference example is provided with the n-Al _0.2 Ga _0.8 As light guide layer 4 only under the active layer 5, and the light guide layer is formed on the active layer 5. Not provided. As a result, electrons as carriers are injected from the n-Al _0.4 Ga _0.6 As cladding layer 3 into the active layer 5 through the n-Al _0.2 Ga _0.8 As light guide layer 4 and holes as carriers are p- Implanted directly into the active layer 5 from the Al _0.4 Ga _0.6 As cladding layer 7. Therefore, the distance that the electrons and holes as carriers reach the active layer 5 is shorter for the holes than for the electrons. Accordingly, the overall resistance is reduced, the heat generation of the element is suppressed, and the reliability is improved. Also in this case, the elliptical ratio is more than “2.5” as in the first embodiment by setting the total film thickness of the active layer 5 and the n-Al _0.2 Ga _0.8 As light guide layer 4 to 1.5 μm or more. Even a small beam shape can be obtained.
[0046]
The present invention is not limited to the above embodiments, for example, the stripe width in above embodiment was 400 [mu] m, the stripe width can be applied to any or more semiconductor lasers 100 [mu] m. In addition to the pulse-driven semiconductor laser, it may be used for a DC-driven (CW) semiconductor laser. Furthermore, in the above embodiment , the active layer, the light guide layer, and the clad layer are made of AlGaAs-based materials, but other materials such as InGaAlP, InGaAsP, InGaAsSb, and AlGaInN-based materials may also be used. In this case, by setting the total thickness of the active layer 5 and the light guide layer to 2.5 μm or more and 5.5 μm or less, the ellipticity of the beam can be set to approximately “2” or less. A laser with an oscillation wavelength corresponding to the material can be obtained.
[0047]
Further, in the above embodiment , the description has been made using the mesa type semiconductor laser, but as shown in FIG. 7, it may be a non-mesa type semiconductor laser.
[0048]
【The invention's effect】
As described above in detail, according to the first, sixth , and seventh aspects of the present invention, a laser beam having a large output and a beam shape close to a circle can be obtained.
[0049]
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, an increase in threshold current and a decrease in light output can be prevented. According to the third and fourth aspects of the invention, in addition to the effect of the first aspect of the invention, the ellipticity of the beam can be made smaller than “2.5”.
[0050]
According to the invention described in claim 5 , in addition to the effect of the invention described in claim 1, heat generation of the element can be suppressed and reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a high-power semiconductor laser according to a first embodiment.
FIG. 2 is a perspective view of a high-power semiconductor laser according to a first embodiment.
FIG. 3 is an energy band diagram of the high-power semiconductor laser according to the first embodiment.
FIG. 4 is a graph showing the relationship between the total thickness of the active layer and the light guide layer and the ellipticity ratio.
FIG. 5 is a cross-sectional view of a high-power semiconductor laser according to a reference example .
FIG. 6 is an energy band diagram of a high-power semiconductor laser according to a reference example .
FIG. 7 is a perspective view of a high-power semiconductor laser according to another embodiment.
FIG. 8 is a perspective view of a conventional high-power semiconductor laser.
FIG. 9 is a cross-sectional view showing a cross section of a beam.
[Explanation of symbols]
N-GaAs substrate as 1 ... semiconductor _{substrate, 3 ... n-Al 0.4 Ga} 0.6 As cladding layer as a first clad layer, 4 ... _{n-Al 0.2} as the first light guide layer Ga _0.8 As light guide layer, 5... Active layer, 6... P- _Al.sub.0.2 Ga _0.8 As light guide layer as second light guide layer, 7... P- as second clad layer Al _0.4 Ga _0.6 As cladding layer, 10... P-type electrode as upper surface electrode, 11... N-type electrode as lower surface electrode

Claims (6)

A semiconductor laser having a stripe width of 100 μm or more,
An active layer in which carriers are injected and light is generated by recombining the injected carriers;
A light guide layer formed adjacent to the upper and lower sides of the active layer and made of a material having a refractive index substantially lower than that of the active layer to confine the light generated in the active layer;
A cladding layer formed above and below the active layer via the light guide layer, and made of a material having a refractive index substantially lower than that of the light guide layer;
A semiconductor laser characterized in that the total thickness of the active layer and the light guide layer is 1.5 μm or more and 5.5 μm or less. 2. The semiconductor laser according to claim 1, wherein the thickness of the active layer is 0.05 μm or more and 0.15 μm or less. 3. The semiconductor laser according to claim 1, wherein the active layer, the light guide layer, and the cladding layer are made of an AlGaAs-based material. The active layer, the light guide layer, and the cladding layer are made of any one of an InGaAlP-based material, an InGaAsP-based material, an InGaAsSb-based material, and an AlGaInN-based material. The semiconductor laser according to any one of the above. The clad layer includes a first conductivity type first clad layer formed on one surface of the active layer and a second conductivity type second clad layer formed on the other surface of the active layer. Become
Further, a semiconductor substrate formed on the first cladding layer side, a bottom electrode formed on the opposite side of the semiconductor substrate from the first cladding layer, and a 100 μm layer formed on the second cladding layer. The semiconductor laser according to claim 1, further comprising an upper surface electrode having the above stripe width. A first conductivity type semiconductor substrate having a bottom electrode on the bottom surface;
A first clad layer of a first conductivity type formed on the upper surface of the semiconductor substrate opposite to the lower electrode;
A first light guide layer of a first conductivity type formed on the first cladding layer and made of an AlGaAs-based material having a refractive index substantially higher than that of the first cladding layer;
It is formed adjacent to the first light guide layer and is made of an AlGaAs-based material. The refractive index is substantially higher than that of the first light guide layer. Carriers are injected and the injected carriers are recycled. An active layer that generates light when combined;
A second light guide layer of a second conductivity type formed adjacent to the active layer and made of an AlGaAs-based material having a refractive index substantially lower than that of the active layer;
A second clad layer of a second conductivity type formed on the second light guide layer and having a refractive index substantially lower than that of the second light guide layer;
A top electrode formed on the second cladding layer and having a stripe width of 100 μm or more, and a total thickness of the first light guide layer, the active layer, and the second light guide layer The semiconductor laser is characterized by having a thickness of 1.5 μm or more and 5.5 μm or less.

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