JPH0484482A - Semiconductor laser element and its manufacture - Google Patents

Abstract

PURPOSE:To get high output properties by relatively decreasing the carrier concentration at the vicinity on the side where a second waveguide layer contacts with an active layer and relatively increasing the carrier concentration at the vicinity on the reverse side. CONSTITUTION:On a substrate 1 are stacked a buffer layer 2, a light waveguide layer 3, an active layer 4, a light waveguide layer 5, an etch stop layer 6, a waveguide layer 7, and a cap layer 8. For the light waveguide layer 5, the p-type impurities concentration is set so that the carrier concentration may be 1-10<17>cm<-3> usually, and for the light waveguide layer 7, p-type impurity concentration is increased relatively and is set so that the carrier concentration may be high at 5X10<17>-10<18>cm<-3>. The impurities diffuse from the light waveguide layer 7 to the active layer 4, and by the concentration of these diffused impurities, ordered array structure occurring in the undoped layer 4 vanishes. Therefore, in this part, the band gap of the active layer comes to show the value in the case of disordered array structure. Moreover, by using quantum well structure for the active layer, the band gap difference with the inside becomes large.

Description

[Detailed description of the invention]

[Industrial Application Field J] The present invention relates to a short-wavelength semiconductor laser device that is effective as a light source for information terminal equipment, etc., and a method for manufacturing the same. [Prior art] A semiconductor laser using a conventional quaternary mixed crystal AΩGaInP is described in Applied Physics Letters Vol. 54, No. 139.
Pages 1 to 1393 (1989) (Appl, Phy
s, Lett, , 54° 1.989 PP1391~
1393), an undoped GaInP layer is used as an active layer, a p-type AQ GaInP layer and an n-type AQGaI
The nP layer is used as an optical waveguide layer. [Problems to be Solved by the Invention] The above-mentioned conventional technology states that a semiconductor laser using AΩGaInP achieves an optical output of about 50 mW in continuous operation at room temperature, but it states that a high output of 60 mW or more cannot be obtained. There was a problem. An object of the present invention is to provide a semiconductor laser device having high output characteristics. Another object of the present invention is to provide a method for manufacturing a semiconductor laser device having high output characteristics.

[Means to solve the problem]

The above purpose is to (1) place (A Q xGal-X
LIn, -mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and X is a value in the range of 0≦x≦0.5). an active layer and a bandcap disposed on both sides of the active layer that is larger than the bandcap of the active layer;
Gax-Y)mInt-mP (However, m represents the above meaning, y is a value in the range of O<y≦1, and
one of the optical waveguide layers is an optical waveguide layer doped with a p-type impurity, and the other is an optical waveguide layer doped with an n-type impurity. In a certain semiconductor laser device, the optical waveguide layer provided on the side closer to the substrate with respect to the active layer is a first optical waveguide layer, and the optical waveguide layer provided on the side farther from the substrate with respect to the active layer. is a second optical waveguide layer, the carrier concentration is relatively low near the side of the second optical waveguide layer in contact with the active layer, and the carrier concentration is relatively low near the opposite side. (2) In the semiconductor laser device described in 1 above, the carrier concentration near the side of the second optical waveguide layer in contact with the active layer is 1×
]0"7~5X1x1017~5x1017cmcm-
A semiconductor laser device characterized in that it is in the range of (
3) In the semiconductor laser device according to 1 or 2 above, the carrier concentration near the side of the second optical waveguide layer opposite to the side in contact with the active layer is in the range of 5×1017 to 1×10111C-3. Characteristic semiconductor laser device,
(4) In the semiconductor laser device according to 1.2 or 3 above, an impurity of the second optical waveguide layer is formed on the top of the second optical waveguide layer near at least one of the cavity end faces of the semiconductor laser device. A semiconductor laser device characterized by providing a semiconductor layer containing impurities of different conductivity types, (5) 4 above.
In the semiconductor laser device described above, the vicinity of the cavity end face of the semiconductor laser device has a length of 10 to 10 mm from the end face.
(6) A semiconductor laser device according to any one of 1 to 5 above, characterized in that the value of m is 0.51. , (7) the semiconductor laser device according to any one of 1 to 6 above, characterized in that the active layer has a single quantum well structure; (8) the semiconductor laser device according to 7 above. , a semiconductor laser device characterized in that the thickness of the single quantum well layer is in the range of 10 to 30 nm; (9) a semiconductor laser device as described in 7 or 8 above, wherein the single quantum well structure has a quantum well structure; The barrier layer is (A Q zGa, z) mIn
, -mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and 2 is a value in the range of O<Z≦0.5). (10) A semiconductor laser device according to any one of 1 to 6 above, wherein the active layer has a multiple quantum well structure; (11) 10 above. (12) The semiconductor laser device as described in 1o or 11 above, wherein the thickness of each quantum well layer of the multi-quantum well structure is in the range of 3 to 15 nm. In the above, the quantum barrier layer of the multi-quantum well structure is (A Q zGal-z) *In1-+++P
(However, m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and 2 is O<z≦0
．． (13) In the semiconductor laser device according to any one of 1 to 12 above, the P-type impurity is Z
A semiconductor laser element (1) characterized by being at least one element selected from the group consisting of n, Mg, and Be.
4) In the semiconductor laser device according to any one of 1 to 12 above, the second optical waveguide layer is an optical waveguide layer doped with a p-type impurity, and the second optical waveguide layer is an optical waveguide layer doped with an n-type impurity. This is achieved by a semiconductor laser device in which a semiconductor layer is disposed, and the n-type impurity doped into the n-type semiconductor layer is at least one element selected from the group consisting of Se and Si. The other purpose is (15) to place (A Q yGa on the substrate)
x-yLInl-mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and y is a value in the range of O<y≦1),
A first step of forming a first optical waveguide layer having impurities of the first conductivity type, on the first optical waveguide layer, (A Q x Ga,
-X)mIJ -1jp (However, m represents the above meaning, X is a value in the range of 0≦x≦0.5, and X〈y
a second step of forming an active layer having a bandgap smaller than that of the first optical waveguide layer;
ax -y) mInx -mP (where m and y represent the above meanings), a third step of forming a second optical waveguide layer having a desired concentration of impurities of the second conductivity type; A fourth step of etching the vicinity of the resonator end face where the optical waveguide layer No. 2 is formed to the vicinity of the active layer, and having impurities of the second conductivity type at a concentration higher than the desired concentration in the etched portion (A Q yGa , -y) mIn, -mP
(16) A method for manufacturing a semiconductor laser device, comprising a fifth step of forming a layer consisting of (m and y have the above meanings) as part of a second optical waveguide layer.
In the method for manufacturing a semiconductor laser device according to Paragraph 15 above,
Formation of the first optical waveguide layer, formation of the active layer, formation of the second optical waveguide layer, and formation of the layer having a carrier concentration higher than the desired concentration are all carried out at 600°C to 75°C.
(17) In the method for manufacturing a semiconductor laser device as described in 15 or 16 above, the impurity of the second conductivity type is P. (18) In the method for manufacturing a semiconductor laser device as described in 17 above, after the fifth step, Se is added on the second optical waveguide layer. , a method for manufacturing a semiconductor laser device, comprising the step of forming an n-type semiconductor layer using a hydrogen compound of at least one element selected from the group consisting of Si as a dopant; , (A QyGa, -y) m■n
1-mp (where m is M determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and y is 0
<y≦1) and has impurities of the first conductivity type. )mIr+1-
mP (However, m represents the above meaning, and X is 0≦x
forming an active layer having a bandgap smaller than the bandgap of the first optical waveguide layer; On the layer, (A Q yGax −Y ) mIn
i - mP (however, m and y represent the above meanings)
a layer having a second conductivity type impurity at a desired concentration, and a layer having an impurity at a concentration higher than the desired concentration on the layer, and a second layer having a portion having a different carrier concentration.
(20) A method for manufacturing a semiconductor laser device as described in 19 above, including the steps of forming the first optical waveguide layer and forming the active layer. The formation of the two layers of the second optical waveguide layer is achieved by a method for manufacturing a semiconductor laser device characterized in that both of the two layers of the second optical waveguide layer are grown by crystal growth at a temperature in the range of 600°C to 750°C.

[Effect]

Experiments have revealed that the p-type impurity doped into the AQ GaInP optical waveguide layer has the property of easily diffusing toward the active layer depending on the crystal growth conditions. FIG. 7(a) shows a portion corresponding to the crystal growth cross-sectional structure in the vicinity of the cavity end face of a semiconductor laser device according to an embodiment of the present invention, and a portion corresponding to the crystal growth cross-sectional structure inside the cavity end face is shown. The operation will be explained with reference to FIG. 7(b). In both FIG. 7(a) and FIG. 7(b), a buffer layer 2 is provided on the substrate 1.
, optical waveguide layer 3, active layer 4, optical waveguide layer 5, etch stop layer 6, optical waveguide layer 7. A cap layer 8 is laminated. The optical waveguide layer 5 has a normal p-type impurity concentration and a carrier concentration of 1.
~5 x 1017 cm-'', and the optical waveguide layer 7 has a relatively high p-type impurity concentration so that the carrier concentration is 5 x 1017-I x 1 x 1017 to 5 x 1
017cmall-". 7th
In figure (a), n-type GaA
An s-block layer 9 is provided, and a contact layer 11 is provided thereon, but in FIG. 7(b), the contact layer 11 is provided without providing a block layer. In the part shown in FIG. 7(a), impurities diffuse from the optical waveguide layer 7 toward the active layer 4, and the ordered structure generated in the undoped active layer 4 disappears due to the concentration of the diffused impurities. This was revealed by electron microscopy.9
Therefore, in this part, the bandgap of the active layer shows the value in the case of a disordered structure. FIG. 8 shows the results of measuring the photoluminescence spectrum corresponding to the active layer after removing the portions shown in FIG. 7(a) and FIG. 7(b) by etching down to the etch stop layer 6. be. The spectrum (A) of the part shown in Figure 7(a) shows a peak wavelength of about 645 nm, while the spectrum (B) of the part shown in Figure 7(b) shows a peak wavelength of about 645 nm.
) showed a peak wavelength of 666 nm. This also means that in the part shown in Figure 7(a), the active layer receives impurity diffusion and has a disordered arrangement structure, and in the part shown in Figure 7(b), which corresponds to the inside of the resonator, there is no active layer. It can be seen that the ordered structure is maintained in the layers. The bandgap of the active layer near the cavity end face is approximately 60 me■ larger than the inside, and for laser light guided to the internal active layer! This has the effect of forming an lS structure. In addition, by using a quantum well structure in the active layer, the AQ composition becomes mixed crystal near the cavity end face due to impurity diffusion, which further increases the band gap difference with the inside, at least 100
~200 meV or more. [Example] Example 1 A perspective view of a semiconductor laser device according to an example of the present invention is shown in FIG. 1, and a manufacturing method thereof will be explained. In FIG. 1, first, an n-GaAs substrate 1 (thickness 100 μm, no=I
n-GaAs buffer layer 2 (thickness 0.5μm, no=2X10111am-') on
, n-(AA yGax-y) a, 5zIna, *s
P optical waveguide layer 3 (thickness 1.0 μm, no=I
×1017~5×1017cman-”, y=0.7)
, undoped (AlfxGa1-x)o, 511no,
*sP active layer 4 (thickness 0.06 μm, x=o), p-(
A Q yGax-y)o, 511n. , 49P optical waveguide layer 5 (thickness 0.3 μm, n^=5×1017 cm−”,
y = 0, 7), P-(AF *Ga1-x
)o, 511n. , 49P engineering stop layer 6 (thickness 0
．． 005+μm, n p, = 8 x 10”cxn
-3,X=0),p-(ARyGam,F)Q,5LI
n0.49P optical waveguide layer 7 (thickness O, 7 μm, n^=~
lXl0111an-” y=0.7), p-Ga,
,,□Ino,4. P cap layer 8 (thickness 0.1 μm,
n^=IX 1016α-3) is sequentially grown epitaxially by metal organic chemical vapor deposition (MOCVD). Next, a Sin insulating film (thickness: 0.2 μm) was deposited. A striped pattern with a width of 5 μm is produced using photolithography. At this time, the direction of the stripes is formed in the <110> direction of the substrate. Using the pattern of the SiO□ insulating film as a mask and using a sulfuric acid solution as an etchant, the cap layer 8 and optical waveguide layer 7 are etched away down to the etch stop layer 6 to form a mesa-shaped ridge stripe as shown in the first m. Fabricate the structure. Then, in order to further process the 5in2 insulating film mask, photolithography is applied to the length Q shown in Figure 1 from the cavity end face of the semiconductor laser.
The portion of the 5 in 2 insulating film mask corresponding to the area is removed by etching. In this embodiment, the length Q is 50 μm, but any length within the range of 1 to 100 μm may be used. Furthermore, with the insulating film mask pattern left as described above, a hydrogen compound of Se is used as a dopant as an n-type impurity by MOCVD, and an n-GaAs block layer 9 is formed.
(thickness 1.0μm, no=4×101@C!D-
”). A hydrogen compound of Si may be used as the dopant. At this time, the impurity diffusion region 10 is grown only in the vicinity of the cavity end face.
(shaded area) is formed. Next, after removing the 5IO2 insulating film mask by etching, the p-GaAs contact layer 1
1 (thickness 3 μm, nA = 1 × 1018a, -3) as MO
Buried growth is performed using the CV method. After this, p electrode 12
Then, an n-electrode 13 is deposited and cut into an element shape by interosseous scribing. The resonator length is in the range of 400 μm. Note that FIG. 2(a) is a cross-sectional view of a portion near the resonator end face of this element, and FIG. 2(b) is a cross-sectional view of a position at a distance of a length Q or more from the resonator end face. According to this embodiment, the threshold current is 30 in continuous operation at room temperature.
Optical output 80~1 while maintaining basic transverse mode at ~50mA
A maximum optical output of 00 mW could be obtained. Furthermore, the optical loss could be suppressed within the range of 20 to 50 an-1. Embodiment 2 Another embodiment of the present invention will be described with reference to FIG. A device was fabricated in the same manner as in Example 1, but unlike in Example 1, the stripe direction of the device was fabricated in the <110> direction of the substrate, resulting in an inverted mesa-shaped ridge stripe structure as shown in FIG. In this example as well, the same effects as in Example 1 were obtained. Embodiment 3 Still another embodiment of the present invention will be described with reference to FIG. A device is manufactured in the same manner as in Example 1, but the active layer has a single quantum well structure. Same as Example 1. The optical waveguide layer 3 is grown by the MOCVD method, and then a single quantum well SCH (Separate Confin) is grown.
elementHeterostructure) structure [undoped CAQzGal-2)0.0In0.41P
Layer guide layer (thickness 15 nm, z=0.4), undoped (A Q xGal-x). , b□Ino, 49P quantum well layer (thickness 15 nm, x = o) - undoped (Al
1zGa, -z). , 5iIn. , 49P guide layer (thickness 15 nm, z=0.4)] was grown as the active layer 4, and then p-(AnyGal-y)o, 5zIn
o, 4qP optical waveguide M5 (thickness 0.3 μm, y==0.7
, nΔ=5×1017an-3), p-(AQaG
al-a) o, 5xIno, 4sP (thickness 5 nm, O≦a
≦0.4) After growing the etch stop layer 6, a device is cut out using the same manufacturing process as in Example 1. The etch stop layer 6 is made of p-AQ bGal-bAs (thickness 5
layer m, 0≦b≦1). According to this embodiment, the threshold current is 15 in continuous operation at room temperature.
Maximum optical output 100-1 in basic transverse mode at ~30mA
Obtained 50 mW. Example 4 A device is manufactured in the same manner as in Example 3, but the active layer has a multiple quantum well structure [undoped (A Q zGa□-2). ,5
11nl+, 49P quantum barrier layer (thickness 5 layers m, z=0.
4) 4 layers and undoped (AQxG
aj, -X) 11.511n0.4IP (thickness 5 layers m,
x=o) layer]. This example also has a threshold current of 15 to 30 in continuous operation at room temperature.
Maximum light output 100-150m in basic transverse mode at mA
I got a W. Embodiment 5 Still another embodiment of the present invention will be described with reference to FIGS. 5 and 6. In the same manner as in Example 1, but in place of the optical waveguide layer 7, p-(A Q yG81-F)o, s x I
n. ,4. P optical waveguide layer 5 (nA=5 x 1017c
xr-'', y=0.7), and after growing up to the cap layer 8, a mask is formed by photolithography to form a striped pattern.At this time, the portion corresponding to the striped part near the cavity end face is also grown. Sex Stop, II
Etch up to F6. After this, the mask is removed and the p-type (AΩyGa1-y)
a, gxlno, *mP buried layer 16 (thickness 0.8 μm
, y=0.7, n ^= 8 x 1017 (!It-
') to grow. The buried layer 16 is an n-type (A Q yGal-y)o,
s□Ino, 4sP (no= 2 X 101san-
3) is fine. After this, n-GaA
The s-block layer 9 is selectively grown by MOCVD. Next, the 5i02 mask is removed, and the buried layer 16 is selectively etched away using an etchant using the n-GaAs block layer 9 as a mask. Through the above steps, the buried layer 16 remains only in the stripe portion below the n-GaAs block layer 9 at the end face of the resonator. Thereafter, it is cut into the shape of an element using the same manufacturing process as in Example 1. The same effects as in Example 1 could be obtained in this example as well. (Effects of the Invention) The semiconductor laser device according to the present invention has a window structure in the vicinity of the cavity end face where the band gap is at least 70 to 90 meV larger than the active layer inside the cavity. We were able to avoid edge destruction, which is a major factor limiting the power output to below 50 mW, and were able to increase the maximum optical output to 60 to 100 mW.Furthermore, by using a single or multiple quantum well structure in the active layer, , the bandgap of the window structure optical waveguide near the cavity end face can be made 100 to 200 meV or more higher than that of the internal active layer, and the maximum optical output can be made 100 to 150 mW.
was able to improve. Furthermore, such a semiconductor laser device could be manufactured using a commonly used manufacturing technique without requiring particularly high skill.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a semiconductor laser device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the vicinity of the resonator end face and the internal structure, and FIGS. 3, 4, and 5 The figure is a perspective cross-sectional view showing a semiconductor laser device according to another embodiment of the present invention, FIG. 6 is a vertical cross-sectional view taken along the line AA' in FIG. . FIG. 8 is a structural diagram of the vicinity and inside of a resonator end face of a striped structure of a semiconductor laser device according to an embodiment of the present invention.
8 is a diagram showing a photoluminescence spectrum from the active layer in the portion shown in FIG. 7. FIG.

Claims (1)

[Claims] 1. On the substrate, (AlfxGa_1_-x)_mIn_
1_-_mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, x
(AlyGa_1_-y)_mIn_1_- _mP (where m represents the above meaning, y is a value in the range of 0<y≦1, and is a value in the relationship x<y), the optical waveguide layer In a semiconductor laser device, one of which is an optical waveguide layer doped with a p-type impurity, and the other is an optical waveguide layer doped with an n-type impurity, the above-mentioned active layer is provided on a side closer to the substrate with respect to the active layer. When the optical waveguide layer is a first optical waveguide layer and the optical waveguide layer provided on the side farther from the substrate with respect to the active layer is a second optical waveguide layer, the activation of the second optical waveguide layer A semiconductor laser device characterized in that the carrier concentration is relatively low near the side in contact with a layer, and the carrier concentration is relatively high near the opposite side. 2. In the semiconductor laser device according to claim 1, the carrier concentration near the side of the second optical waveguide layer in contact with the active layer is 1 x 10^1^7 to 5 x 10^1^7 cm^-. ^
3. A semiconductor laser device characterized in that the range is 3. 3. The semiconductor laser device according to claim 1 or 2,
The carrier concentration near the side of the second optical waveguide layer opposite to the side in contact with the active layer is 5×10^1^7 to 1×10^1
A semiconductor laser device characterized in that the diameter is in the range of ^8cm^-^3. 4. The semiconductor laser device according to claim 1, 2 or 3, wherein an impurity of the second optical waveguide layer and an upper part of the second optical waveguide layer near at least one of the cavity end faces of the semiconductor laser device A semiconductor laser device comprising a semiconductor layer containing impurities of different conductivity types. 5. The semiconductor laser device according to claim 4, wherein the vicinity of the resonator end face of the semiconductor laser device has a length ranging from 10 to 100 μm from the end face. 6. The semiconductor laser device according to claim 1, wherein the value of m is 0.51. 7. The semiconductor laser device according to claim 1, wherein the active layer has a single quantum well structure. 8. The semiconductor laser device according to claim 7, wherein the single quantum well layer has a thickness in the range of 10 to 30 nm. 9. The semiconductor laser device according to claim 7 or 8,
The quantum barrier layer of the single quantum well structure is (AlzGa_
1_-z)_mIn_1_-_mP (where, m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, and z is a value in the range of 0<z≦0.5 ) A semiconductor laser device comprising: 10. The semiconductor laser device according to claim 1, wherein the active layer has a multiple quantum well structure. 11. The semiconductor laser device according to claim 10, wherein the thickness of each quantum well layer of the multiple quantum well structure is 3.
A semiconductor laser device characterized in that the wavelength is in the range of 15 nm to 15 nm. 12. In the semiconductor laser device according to claim 10 or 11, the quantum barrier layer having the multiple quantum well structure has (Alz
Ga_1_-Z)_mIn_1_-_mP (however, m
is a value determined so that the lattice constant of the semiconductor is substantially the same as the lattice constant of the substrate, and z is a value in the range of 0<z≦0.5). . 13. In the semiconductor laser device according to any one of claims 1 to 12, the p-type impurity is Zn, Mg, Be.
A semiconductor laser element characterized by being at least one element selected from the group consisting of: 14. The semiconductor laser device according to claim 1, wherein the second optical waveguide layer is an optical waveguide layer doped with a p-type impurity, and the second optical waveguide layer is an optical waveguide layer doped with a p-type impurity.
1. A semiconductor laser device, wherein a semiconductor laser device is provided with an n-type semiconductor layer, and an n-type impurity doped into the n-type semiconductor layer is at least one element selected from the group consisting of Se and Si. 15. On the substrate, (AlyGa_1_-y)_mIn_
1_-_mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, y
is a value in the range of 0<y≦1), a first step of forming a first optical waveguide layer having a first conductivity type impurity;
On the first optical waveguide layer, (AlxGa_1_-x)_m
In_1_-_mP (where m represents the above meaning, x is a value in the range of 0≦x≦0.5, and is a value in the relationship x<y), and the first optical waveguide A second step of forming an active layer with a bandcap smaller than the bandcap of the layer, on the active layer, (AlyGa_1_-
y) a third step of forming a second optical waveguide layer made of _mIn_1_-_mP (where m and y represent the above meanings) and having a desired concentration of second conductivity type impurities; A fourth step of etching the vicinity of the resonator end face where the optical waveguide layer is formed to the vicinity of the active layer, and having a second conductivity type impurity in the etched portion at a concentration higher than the desired concentration (AlyGa_1_-_y)_mIn_1_ −＿
A method for manufacturing a semiconductor laser device, comprising a fifth step of forming a layer made of mP (where m and y have the above meanings) as part of a second optical waveguide layer. 16. The method for manufacturing a semiconductor laser device according to claim 15, wherein the formation of the first optical waveguide layer, the formation of the active layer, the formation of the second optical waveguide layer, and the steps of forming the carrier concentration higher than the desired concentration are performed. 1. A method for manufacturing a semiconductor laser device, characterized in that each layer is formed by crystal growth at a temperature in the range of 600° C. to 750° C. 17. The method of manufacturing a semiconductor laser device according to claim 15 or 16, wherein the second conductivity type impurity is a p-type impurity. 18. The method for manufacturing a semiconductor laser device according to claim 17, wherein after the fifth step, a hydrogen compound of at least one element selected from the group consisting of Se and Si is placed on the second optical waveguide layer. 1. A method for manufacturing a semiconductor laser device, comprising the step of forming an n-type semiconductor layer using as a dopant. 19. On the substrate, (AlyGa_1_-y)_mIn_
1_-_mP (where m is a value determined so that the lattice constant of this semiconductor is substantially the same as the lattice constant of the substrate, y
is a value in the range of 0<y≦1), a step of forming a first optical waveguide layer having a first conductivity type impurity, on the first optical waveguide layer, (AlxGa_1_-x); _mIn
_1_-_mP (where m represents the above meaning, x
is a value in the range of 0≦x≦0.5, and is a value in the relationship x<y), forming an active layer having a band gap smaller than the band gap of the first optical waveguide layer. On the process and the active layer, (AlyGa_1_-y)_
mIn_1_-_mP (where m and y represent the above meanings), a layer having a second conductivity type impurity at a desired concentration, and a layer having an impurity at a concentration higher than the desired concentration on the layer; 1. A method for manufacturing a semiconductor laser device, comprising the step of forming a second optical waveguide layer having portions having different carrier concentrations. 20. In the method for manufacturing a semiconductor laser device according to claim 19, the formation of the first optical waveguide layer, the formation of the active layer, and the formation of the two layers of the second optical waveguide layer are all performed in step 6.
A method for manufacturing a semiconductor laser device, characterized in that crystal growth is performed at a temperature in the range of 00°C to 750°C.