JP2001015862A - Semiconductor laser device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser device which is equipped with an etching stop layer which a high etching-controllability and capable of preventing light absorption from an active layer. SOLUTION: At least, a first conductivity-type AlGaInP clad layer 104 whose lattice constant is between those of GaAs and GaP, a GaInAsP active layer 105, a second conductivity-type first AlGaInP clad layer 106 whose lattice constant is equal to that of the clad layer 104, a second conductivity-type GaInP etching stop layer 107, and a second conductivity-type second AlGaInP clad layer 108 whose lattice constant is equal to that of the clad layer 104 are successively laminated on a semiconductor substrate 101, where the lattice constant of the etching stop layer 107 is nearly equal to that of the first conductivity-type clad layer 104, and the band gap of the etching stop layer 107 is larger than that of the active layer 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor laser device used for an optical disk storage device or a light source for optical information processing, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In general, in an AlGaInP red laser, a current path is narrowed by etching in a stripe shape. In this etching process, etching is performed to a required depth with a good reproducibility and a uniform depth. It is difficult. Therefore, conventionally, an etching stop layer is generally provided, and the etching depth is controlled by utilizing the fact that the etching is stopped when the etching stop layer is exposed or the etching speed is reduced.

As the above-described etching stop layer, AlGaInP used as a cladding layer or GaInP having a high etching selectivity with respect to GaAs used as a current confinement layer is most effective. However, usually
Since the active layer of the visible semiconductor laser is made of GaInP, the light from the active layer is absorbed by the GaInP etching stop layer, which causes deterioration in characteristics during high-power operation. To solve this problem, the following structure of a semiconductor laser has been proposed.

FIG. 11 is a diagram showing an AlGaInP-based semiconductor laser disclosed in Japanese Patent Application Laid-Open No. 08-204277. The semiconductor laser of FIG. 11 has an n-type GaAs buffer layer 2 and an n-type AlGa
An InP cladding layer 3, an active layer 4 having a multiple quantum well structure, and a first cladding layer 5 made of p-type AlGaInP.
A, a p-type GaInP etching stop layer 9, a second cladding layer 5B made of p-type AlGaInP, and a p-type GaAs cap layer 6 are sequentially and epitaxially grown.

Then, a mask layer made of SiO _{2 is} formed on the stripe-shaped current path in the center of the epitaxial growth layer, and the trench is formed by etching using the mask layer as an etching mask. Here, etching is performed using a mixture of HCl, H ₂ O ₂ and H ₂ O or H ₂ SO _2.
4 and a mixture of H ₂ O ₂ and H ₂ O,
When the etching stop layer 9 is exposed, the etching is substantially stopped, and the depth of the groove 7 is defined at the position where the etching stop layer 9 is formed. Thereafter, an n-type GaAs current confinement layer 8 is formed in the trench 7 by selective MOCVD using the mask layer as a mask. Thereafter, a flattening layer is formed on the entire surface, and the surface is planarly etched to planarize the element surface. ,
The structure as shown in FIG. 11 is obtained.

In the semiconductor laser shown in FIG. 11, the band gap is made larger than that of the active layer 4 by causing the GaInP etching stop layer 9 to have a tensile strain. To avoid being absorbed by

[0007] FIG.
AlGaInP red semiconductor laser
FIG. The semiconductor laser shown in FIG.
On the substrate 11, for example, using a MOCVD apparatus,
1.5 μm n-type (Al_0.7Ga_{0. Three})_0.5In_0.5P crack
Layer 12, undoped Ga_0.5In_0.5P active layer 16, layer
0.25 μm thick first p-type (Al_0.7Ga_0.3)_0.5In
_0.5P cladding layer 13a, etching stop layer 17,
Second p-type (Al_0.7Ga_0.3)_0.5I
n_0.5P cladding layer 13b is formed sequentially
Have been.

Here, the etching stop layer 17 is
1 p-type (Al_0.7Ga_0.3)_0.5In_{0 .Five}P clad layer 13
a on the p-type Ga_0.57In_0.43P well layer (layer thickness is 1.7n
m), p-type (Al_0.7Ga_0.3)_0.5In_0.5P barrier layer (layer
Thickness 2 nm), p-type Ga_0.57In_0.43P well layer (layer thickness is
1.7 nm), p-type (Al_0.7Ga_0.3)_0.5In_0.5P Bali
Layer (layer thickness is 1 nm), p-type Ga_0.57In_0.43P well layer
(A layer thickness of 1.7 nm) is formed in order.
You.

[0009] In the semiconductor laser of FIG. 12, after the selective etching of the second p-type _{(Al 0.7 Ga 0.3) 0.5 In} 0.5 P clad layer 13b is formed in a mesa, the second p-type (Al _0.7 Ga _An n-type GaAs current block layer 14 is formed again by using the MOCVD apparatus in a portion where the _0.3 ) _0.5 In _0.5 P clad layer 13b is removed by etching. Further, a second mesa-shaped p-type (Al _0.7 Ga _0.3 )
_A p-type GaAs cap layer 15 is formed on the _0.5 In _0.5 P cladding layer 13 b and the n-type GaAs current blocking layer 14. An n-side electrode 18 is provided on the lowermost surface of the layer structure.
Is formed, and a p-side electrode 19 is formed on the uppermost surface.

In the semiconductor laser structure shown in FIG. 12, a sulfuric acid-based etching solution is used at the time of mesa etching.
It will stop at any of the _0.57 In _0.43 P well layers.

In the semiconductor laser structure shown in FIG. 12, a 0.5% tensile strain is introduced into the p-type Ga _0.57 In _0.43 P well layer of the etching stop layer 17, and the band gap wavelength is shortened by the quantum effect. Is becoming Accordingly, the light of the active layer 16 is not absorbed by the etching stop layer 17, and a semiconductor laser having good current characteristics at the time of high output operation can be obtained.

[0012]

As described above, FIG.
In the conventional AlGaInP-based semiconductor laser shown in FIG. 12, in order to prevent light from the GaInP active layer from being absorbed by the GaInP etching stop layer, a tensile strain is introduced into the etching stop layer to increase the band gap from the active layer. Is also bigger.

However, since the etching stop layer in which the tensile strain is introduced has a different lattice constant from the substrate, it is necessary to set the thickness of the etching stop layer to be equal to or less than the critical film thickness. Can not do it. In particular, the emission wavelength of the active layer is 633 nm.
When the wavelength becomes short, the amount of strain is increased to 1% or more or several nm to shorten the etching stop layer.
Must be formed, and in this case, the thickness of the etching stop layer becomes 5 nm or less. If the thickness of the etching stop layer is too thin, there is a problem that the etching proceeds to the active layer by partially over-etching due to the in-plane distribution of the etching rate or the like.

When AlGaInP is used as the material of the etching stop layer, the band gap can be easily made larger than that of the active layer by lattice matching with the GaAs substrate, but the etching selectivity with the AlGaInP cladding layer becomes smaller. As a result, there is a problem that the controllability of the etching depth is reduced.

It is an object of the present invention to provide a semiconductor laser device having an etching stop layer which has high etching controllability and does not cause light absorption from an active layer, and a method of manufacturing the same.

[0016]

In order to achieve the above object, according to the present invention, there is provided an AlGaInP cladding of a first conductivity type having at least a lattice constant between GaAs and GaP on a semiconductor substrate. Layer, a GaInAsP active layer, a first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type, a GaInP etching stop layer of the second conductivity type, and a first conductivity type. A second conductivity type second AlGaInP cladding layer having the same lattice constant as the cladding layer is sequentially laminated, and the lattice constant of the etching stop layer is substantially equal to the lattice constant of the first conductivity type cladding layer, and The band gap of the etching stop layer is larger than the band gap of the active layer.

According to a second aspect of the present invention, at least a first conductivity type having a lattice constant between GaAs and GaP is provided on a GaAs or GaP substrate via a buffer layer for eliminating lattice mismatch. An AlGaInP cladding layer, a GaInAsP active layer, and a first AlGaI of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type.
An nP cladding layer, a second conductivity type GaInP etching stop layer, and a second conductivity type second AlGaInP cladding layer having the same lattice constant as the first conductivity type cladding layer are sequentially laminated. The lattice constant of the layer is substantially equal to the lattice constant of the cladding layer of the first conductivity type, and the band gap of the etching stop layer is larger than the band gap of the active layer.

According to a third aspect of the present invention, there is provided the semiconductor laser device according to the first or second aspect.
Between the AlGaInP cladding layer of the conductivity type and the GaInAsP active layer, the GaInAsP active layer and the first of the second conductivity type.
One or both of the AlGaInP cladding layer and the GaI layer having a larger band gap than the active layer.
An optical waveguide layer made of nP is provided.

According to a fourth aspect of the present invention, there is provided the semiconductor laser device according to any one of the first to third aspects, wherein the GaInP etching stop layer has both sides of a stripe-shaped current path interposed therebetween. A current confinement layer is buried therein.

According to a fifth aspect of the present invention, in the semiconductor laser device of the fourth aspect, the current confinement layer has a larger band gap than the active layer, and has a larger band gap than the second conductivity type AlGaInP clad layer. It is characterized by a small refractive index.

According to a sixth aspect of the present invention, there is provided a semiconductor device comprising at least a first conductivity type AlGaInP cladding layer having a lattice constant between GaAs and GaP,
An InAsP active layer, a first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type, a GaInP etching stop layer of the second conductivity type, and a cladding layer of the first conductivity type. A step of sequentially stacking a second AlGaInP cladding layer of the second conductivity type having the same lattice constant, and a step of etching the second AlGaInP cladding layer of the second conductivity type in a stripe shape up to an etching stop layer to form a ridge stripe structure. Forming,
Selectively embedding a first-conductivity-type current constriction layer on both sides of a second-conductivity-type second cladding layer etched in a stripe shape; a second-conductivity-type etching stop layer; Laminating a second conductivity type contact layer on the current confinement layer.

According to a seventh aspect of the present invention, there is provided a semiconductor device, comprising: a first conductivity type AlGaInP cladding layer having a lattice constant between GaAs and GaP;
aInAsP active layer, a first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type, a GaInP etching stop layer of the second conductivity type, and a current confinement layer of the first conductivity type Sequentially forming a current confining layer, etching the current confining layer in a stripe shape up to the etching stop layer to form a groove, and forming a groove on the exposed second conductive type etching stop layer and the first conductive type current confinement layer. And laminating a second AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first configuration example of a semiconductor laser device according to the present invention. The semiconductor laser device of FIG. 1 includes a semiconductor substrate (for example, GaAs or GaP substrate) 101 on which at least a first conductivity type (for example, n-type) Al having a lattice constant between GaAs and GaP.
GaInP cladding layer 104, GaInAsP active layer 105, and first AlGa of the second conductivity type (for example, p-type) having the same lattice constant as cladding layer 104 of the first conductivity type.
InP cladding layer 106, second conductivity type GaInP etching stop layer 107, and second conductivity type second Al having the same lattice constant as first conductivity type cladding layer 104.
A GaInP cladding layer 108 is sequentially laminated.

Here, the lattice constant of the etching stop layer 107 is substantially equal to the lattice constant of the cladding layer 104 of the first conductivity type, and the band gap of the etching stop layer 107 is larger than the band gap of the active layer 105. ing.

FIG. 2 is a diagram showing a more specific configuration example of the semiconductor laser device of FIG. The semiconductor laser device of FIG. 2 is different from the semiconductor laser device of FIG.
A buffer layer 103 for eliminating lattice mismatch is provided between the first conductive type AlGaInP clad layer 104 and the first conductive type AlGaInP clad layer 104.

FIG. 3 shows components of the semiconductor laser device shown in FIGS. 1 and 2.
It is a figure which shows a body example. Referring to FIG.
The n-type GaAs substrate 101 has n-type GaAs
s_yP_1-yThe composition gradient layer 102 is laminated. Note that n
Type GaAs_yP_1-yThe composition gradient layer 102 is formed by the VPE method.
Grown while gradually changing the composition y from 1 to 0.6
I have. And n-type GaAs_yP_1-yOn the composition gradient layer 102
Has n-type GaAs _0.6P_0.4Buffer layer 103, n-type A
lGaInP cladding layer 104, undoped GaAsP
Active layer 105, first p-type AlGaInP cladding layer 1
06, p-type GaInP etching stop layer 107,
2 p-type AlGaInP cladding layer 108, p-type GaI
nP spike prevention layer 109, p-type GaAsP contact
The layers 110 are sequentially stacked by MOCVD. n
Type GaAs_yP_1-yFormed on the composition gradient layer 102
The lattice constant of the laminated structure is n-type GaAs_0.6P_0.4Bag
The composition is lattice-matched to the far layer 103.

In the semiconductor laser device of FIG. 3, the p-type GaInP etching stop layer 1
Thus, a ridge stripe structure having a stripe width of 5 μm is formed. In this etching, the p-type GaAsP contact layer 110 is formed by a sulfuric acid-based etchant using the SiO ₂ layer as a mask.
Chemical etching is selectively performed up to the P-spike prevention layer 109, and then the p-type GaInP spike-prevention layer 109 is removed with hydrochloric acid.
P-type AlGaInP cladding layer 108
The P etching stop layer 107 is selectively etched. Since the GaInP is hardly etched by the sulfuric acid-based etchant, the etching is almost stopped when the p-type GaInP etching stop layer 107 is exposed. Further, a p-type GaInP etching stop layer 1
07 has a composition that is lattice-matched to the n-type GaAs _0.6 P _0.4 buffer layer 103, so that the layer thickness is, for example, 5
It can be formed as thick as 0 nm. Therefore, p-type Ga
The etching depth is not over-etched beyond the InP etching stop layer 107, and the etching depth is p-type Ga.
It is possible to uniformly control the position of the InP etching stop layer 107.

Then, except for the top of the ridge stripe, the SiO ₂ insulating layer 111 is covered,
The current is confined in the ridge stripe region having a width of 5 μm.

In FIG. 3, reference numeral 112 denotes a p-side electrode formed on the front surface of the device, and 113 denotes an n-side electrode formed on the back surface of the device.

In FIG. 3, the GaAsP active layer 105
Has the same composition as the n-type GaAs _0.6 P _0.4 buffer layer 103, and has a band gap wavelength of about 650 nm. p-type GaInP etching stop layer 1 lattice-matched to n-type GaAs _0.6 P _0.4 buffer layer 103
The band gap wavelength of 07 is 560 nm, which is shorter than that of the non-doped GaAsP active layer 105. Therefore, the p-type GaInP etching stop layer 10
7 does not absorb the light emitted from the active layer 105,
Deterioration of output characteristics can be suppressed even during high output operation.

FIG. 4 is a diagram showing a second configuration example of the semiconductor laser device according to the present invention. The semiconductor laser device of FIG. 4 is the same as the semiconductor laser device of the first configuration example described above except that the AlGaInP cladding layer 104 of the first conductivity type is
between the aInAsP active layer 105 and / or the GaInAsP active layer 105 and the second conductive type first AlGaInP cladding layer 106 (both in the example of FIG. 4); Also, optical waveguide layers 201 and 203 made of GaInP having a large band gap are provided.

The semiconductor laser device shown in FIG.
P is an active layer 105, and GaInP is an optical waveguide layer 201,
The cladding layers 104 and 10 are made of AlGaInP.
The SCH structure is 6. The optical waveguide layers 201 and 203 having a high light density are made of a semiconductor material containing no Al. Therefore, the surface state density caused by Al can be reduced, and the end face degradation can be suppressed. Thereby, COD can be suppressed and the maximum light output of the laser can be improved.

FIG. 5 is a diagram showing a third configuration example of the semiconductor laser device according to the present invention. The semiconductor laser device of FIG. 5 is different from the semiconductor laser device of the first configuration example or the second configuration example described above in that the current constriction layers 204 are provided on both sides of the GaInP etching stop layer 107 with a stripe-shaped current path therebetween. Is embedded. Note that the example of FIG. 5 shows a second configuration example, that is, a case where the present invention is applied to the semiconductor laser device of FIG.

Here, the current confinement layer 204 is formed of the active layer 10
5, and has a smaller refractive index than the AlGaInP cladding layers 106 and 108 of the second conductivity type.

In the semiconductor laser device shown in FIG.
N-type GaAs on the side of the ripe_0.6P_{0 .Four}Current confinement layer 204
Embedded on the outside of the ridge stripe
No current flows due to the pnpn structure. Therefore,
Current can be concentrated in the ridge stripe area
You.

In the semiconductor laser device of the example shown in FIG.
The n-type GaAs _0.6 P _0.4 current confinement layer 204 is the active layer 105
The upper optical waveguide layer 2
03 absorbs light that has leaked out to the p-type AlGaInP cladding layer 106 side. Therefore, waveguide loss occurs outside the ridge stripe, and light is confined in the ridge stripe. Therefore, a semiconductor laser of a refractive index guided type having a stable transverse mode can be operated in a single mode even at a high output.

Further, since the n-type GaAs _0.6 P _0.4 current confinement layer 204 is embedded in the device, it is not necessary to form an SiO ₂ insulating film on the device surface. Thereby, the heat radiation characteristics can be improved as compared with the above-described structures shown in FIGS. And p-type GaAs
Since the contact area between the sP contact layer 110 and the p-side electrode 112 can be increased, the contact resistance can be reduced,
The operating voltage of the semiconductor laser can be reduced.

A method of manufacturing a semiconductor laser device having a structure in which a current constriction layer 204 is embedded on both sides of a GaInP etching stop layer 107 with a stripe-shaped current path interposed therebetween, as shown in FIG. An example of a manufacturing process can be employed. That is, the semiconductor substrate 101
A first conductivity type AlGaInP cladding layer 104 having a lattice constant of at least between GaAs and GaP.
, A GaInAsP active layer 105, and a second conductivity type first layer having the same lattice constant as the first conductivity type cladding layer 104.
AlGaInP cladding layer 106 and second conductivity type G
successively stacking an aInP etching stop layer 107 and a second AlGaInP cladding layer 108 of the second conductivity type having the same lattice constant as the cladding layer 104 of the first conductivity type; A step of forming a ridge stripe structure by stripping the cladding layer to the etching stop layer 107 to form a ridge stripe structure; and forming a first conductivity type on both sides of the striped second cladding layer of the second conductivity type. A step of selectively embedding the current confinement layer 204 and a step of laminating a second conductivity type contact layer 109 on the second conductivity type etching stop layer 107 and the first conductivity type current confinement layer 204. A manufacturing method can be adopted.

According to this example of the manufacturing process, a semiconductor laser device as shown in FIG. 5 can be manufactured. In this example of the manufacturing process, the second conductive type second cladding layer 108 and the first conductive type current confinement layer 204 are
A contact layer 109 of the second conductivity type is formed. Therefore, the contact area between the second conductivity type (p-side) electrode and the second conductivity type (p-type) contact layer 109 can be increased, so that the contact resistance can be reduced and the operating voltage of the semiconductor laser can be reduced. Can be.

FIG. 6 is a diagram showing a specific example of a manufacturing process example of the semiconductor laser device of FIG. In the manufacturing process example of FIG. 6, first, an n-type GaAs _y P
_{A 1-y} composition gradient layer 102 is formed. Note that n-type GaAs _y
The P _{1 -y} composition gradient layer 102 has a composition y of 1 by the VPE method.
It grows while gradually changing from 0.6 to 0.6. And n
N-type GaAs on the GaAs _y P _1-y composition gradient layer 102
_0.6 P _0.4 buffer layer 103, n-type AlGaInP cladding layer 104, GaInP lower optical waveguide layer 201, GaIn
AsP active layer 105, GaInP upper optical waveguide layer 203,
First p-type AlGaInP cladding layer 106, p-type Ga
InP etching stop layer 107, second p-type AlG
The aInP cladding layer 108 and the p-type GaInP spike prevention layer 109 are sequentially stacked by MOCVD (FIG. 6).
(a)). The lattice constant of the stacked structure formed on the n-type GaAs _y P _1-y composition gradient layer 102 is n-type GaAs _0.6 P
_{0.4 The} composition is lattice matched to the buffer layer 103.

Next, using the SiO ₂ mask layer 301 as a mask, chemical etching is performed from the surface of the p-type GaInP anti-spike layer 109 to the p-type GaInP etching stop layer 107 to form a ridge stripe structure having a stripe width of 5 μm (FIG. b)). Etching is p-type Ga
The InP spike prevention layer 109 is removed with hydrochloric acid, and a second p-type AlGaIn is further removed with a sulfuric acid-based etchant.
The P cladding layer 108 is selectively etched down to the p-type GaInP etching stop layer 107. Since the GaInP is hardly etched by the sulfuric acid-based etchant, the etching is almost stopped when the p-type GaInP etching stop layer 107 is exposed. Furthermore, p-type Ga
The InP etching stop layer 107 is made of n-type GaAs
_Since the composition is lattice-matched to the _0.6 P _0.4 buffer layer 103, the layer thickness can be formed as large as 50 nm, for example. Therefore, the etching depth can be uniformly controlled at the position of the p-type GaInP etching stop layer 107 without being over-etched beyond the p-type GaInP etching stop layer 107.

Next, on both sides of the second p-type AlGaInP cladding layer 108 etched in a stripe shape, n
Type GaAs _0.6 P _0.4 current confinement layer 204 is formed (FIG. 6).
(c)). The n-type GaAs _0.6 P _0.4 current confinement layer 204
Can be formed by MOCVD selective growth using the SiO ₂ mask layer 301 used as an etching mask as a mask for selective growth.

Next, after removing the SiO ₂ mask layer 301, the p-type GInP etching stop layer 107 and the n-type GaAs _0.6 P _0.4
The aAsP contact layer 110 is formed, and the element surface is almost flattened (FIG. 6D).

Finally, a p-side electrode 112 is formed on the entire front surface of the device.
Is formed, and an n-side electrode 113 is further formed on the back surface side of the substrate (FIG. 6E).

GaIn lattice matched to GaAs _0.6 P _0.4
The band gap wavelength of AsP is from 560 nm to 650 nm.
nm. For example, when obtaining a red laser beam of 630 nm, Ga _0.95 In _0.05 As
_0.5 P _0.5 may be used as the active layer 105. p-type Ga
Since the band gap of the InP etching stop layer 107 is larger than the band gap of the GaInAsP active layer 105, the p-type GaInP etching stop layer 1
07 does not absorb the light emitted from the active layer 105 and can suppress the deterioration of the output characteristics even at the time of high output operation.

FIG. 7 is a diagram showing a fourth configuration example of the semiconductor laser device according to the present invention. The semiconductor laser device of FIG. 7 has a semiconductor substrate (for example, a GaAs or GaP substrate).
A first conductivity type AlGaInP cladding layer 104 having at least a lattice constant between GaAs and GaP, a GaInAsP active layer 105, and a second conductivity type having the same lattice constant as the first conductivity type cladding layer 104 are formed on the substrate 101. A first conductive type AlGaInP cladding layer 106, a second conductive type GaInP etching stop layer 107, and a first conductive type current confinement layer 204 are sequentially stacked, and the current confinement layer 204 is striped to the etching stop layer 107. A groove portion is formed by etching in the same manner, and a second conductive type cladding layer 104 having the same lattice constant as the first conductive type cladding layer 104 is formed on the exposed second conductive type etching stop layer 107 and the first conductive type current confinement layer 204. 2nd conductivity type second AlGaInP
The cladding layer 108 is formed by lamination.

FIG. 8 is a diagram showing a more specific configuration example of the semiconductor laser device of FIG. In the example of FIG. 8, in the semiconductor laser device of FIG. 7, between the AlGaInP cladding layer 104 of the first conductivity type and the GaInAsP active layer 105,
GaInAsP active layer 105 and first Al of second conductivity type
Optical waveguide layers 201 and 203 made of GaInP having a band gap larger than that of the active layer 105 are provided on one or both of the GaInP cladding layers 106 (both in the example of FIG. 8). Also, p-type GaIn
P etching stop layer 107 and n-type GaAs _0.6 P
_{0.4 On the} current confinement layer 204, a second p-type AlGaIn
P cladding layer 108, p-type GaInP spike prevention layer 1
09 and a p-type GaAsP contact layer 110 are sequentially laminated.

The p-side electrode 11 is formed on the entire front surface of the device.
2, and an n-side electrode 113 is formed on the back surface of the substrate.

FIG. 9 is a process for fabricating the semiconductor laser device of FIG.
It is a figure showing an example. In the example of FIG. 9, first, n-type GaAs
n-type GaAs on the s substrate 101_yP_1-yComposition gradient layer 10
Form 2 Note that n-type GaAs_yP_1-yComposition gradient layer 1
02 gradually increases the composition y from 1 to 0.6 by the VPE method
Grow while changing to And n-type GaAs_yP_1-yset
N-type GaAs is formed on the graded layer 102_0.6P_0.4Buffer layer
103, n-type AlGaInP cladding layer 104, GaI
nP lower optical waveguide layer 201, multiple quantum well active layer 105,
GaInP upper optical waveguide layer 203, first p-type AlGaI
nP cladding layer 106, p-type GaInP etching
Layer 107, n-type GaAs_0.6P_0.4Current confinement layer 204
Are sequentially laminated by MOCVD (FIG. 9A). n-type
GaAs _yP_1-yLaminated structure formed on composition gradient layer 102
The lattice constant of the structure is n except for the multiple quantum well active layer 105.
Type GaAs_0.6P_0.4A set lattice-matched to the buffer layer 103
It has become. The multiple quantum well active layer 105 is made of GaAs
s_0.6P_0.4With a layer thickness of 8 nm having a compressive strain of 1%
Ga_0.75In_0.25As_0.3P_0.7Is a well layer and has a layer thickness of 5n.
Ga of m_0.7In_0.3P is configured as a barrier layer
You. The number of wells is, for example, three layers.

Next, using the SiO ₂ mask layer 501 as a mask, chemical etching is performed from the surface of the n-type GaAs _0.6 P _0.4 current confinement 204 to the p-type GaInP etching stop layer 107 to form a groove having a stripe width of 5 μm (FIG. b)). In the etching, the n-type GaAs _0.6 P _0.4 current confinement layer 204 is p-type with a mixed solution of sulfuric acid, hydrogen peroxide and water.
The etching is selectively performed up to the GaInP etching stop layer 107. Since the GaInP is hardly etched by the sulfuric acid-based etchant, the etching is almost stopped when the p-type GaInP etching stop layer 107 is exposed. Further, since the p-type GaInP etching stop layer 107 has a composition that lattice-matches with the n-type GaAs _0.6 P _0.4 buffer layer 103, the layer thickness is, for example, 50 μm.
It can be formed as thick as nm. Therefore, p-type GaI
The etching depth does not exceed the nP etching stop layer 107 and the etching depth is p-type GaI.
It can be controlled uniformly at the position of the nP etching stop layer 107.

Next, after removing the SiO ₂ mask layer 501, a second p-type AlGaInP cladding is formed on the p-type GaInP etching stop layer 107 and the n-type GaAs _0.6 P _0.4 current confinement layer 204 which are exposed by etching. Layer 108, p-type GaInP spike prevention layer 109, p-type G
The aAsP contact layers 110 are sequentially laminated (FIG. 9).
(c)).

Finally, a p-side electrode 112 is formed on the entire front side of the device, and an n-side electrode 113 is formed on the back side of the substrate (FIG. 9D).

The band gap wavelength of the quantum well layer is 635.
nm, which is longer than the band gap wavelength of the p-type GaInP etching stop layer 107. Therefore, the p-type GaInP etching stop layer 10
7 does not absorb the light emitted by the active layer, so that the output characteristics can be prevented from deteriorating even during high-output operation.

Further, n-type GaAs _0.6 P
_{Since the 0.4} current confinement layer 204 is formed, a pnpn structure is formed outside the groove, and no current flows. Therefore, the current can be concentrated on the groove.

The n-type GaAs _0.6 P _0.4 current confinement layer 2
Since the band gap of the active layer 105 is smaller than that of the active layer 105, the layer 04 absorbs the light leaking from the upper optical waveguide layer 203 toward the p-type AlGaInP clad layer 106. Therefore, waveguide loss occurs outside the groove, and light is confined inside the groove. Therefore, a semiconductor laser of a refractive index guided type having a stable transverse mode can be operated in a single mode even at a high output.

Then, the p-type GaAsP contact layer 11
Since the contact area between 0 and the p-side electrode 112 can be increased,
The contact resistance can be reduced, and the operating voltage of the semiconductor laser can be reduced.

Further, in the method of manufacturing the semiconductor laser device shown in FIG. 9, a similar structure can be formed by reducing the number of times of crystal growth by one as compared with the manufacturing method shown in FIG. . Therefore, the manufacturing process is simplified.
That is, in the method of manufacturing the semiconductor laser device shown in FIG. 6, the stacked structure above the buffer layer 103 for alleviating the lattice mismatch is performed by three crystal growths. That is, FIG.
In the method of manufacturing the semiconductor laser device shown in FIG. 1, the first growth of stacking up to the second AlGaInP cladding layer 108 of the second conductivity type, and the second cladding layer 108 of the second conductivity type etched in a stripe shape. On both sides of the first conductive type current confinement layer 204 is selectively buried, and a second conductive type current confinement layer 204 is formed on the second conductive type second cladding layer 108 and the first conductive type current confinement layer 204. The stacked structure is constituted by three crystal growths including the third growth in which the conductive contact layer 110 is stacked. On the other hand, according to the manufacturing method of the semiconductor laser device shown in FIG. 9, since the current confinement layer 204 can be formed by one growth, the same structure can be formed by reducing the number of times of crystal growth by one. Can be. Therefore, the manufacturing process can be simplified.

After the etching, the surface of the laminated structure is made of Al.
The material does not contain. Therefore, the influence of surface oxidation is reduced, and even if regrowth is performed thereon, it is possible to suppress a decrease in crystallinity at the interface. That is, the current confinement layer 20
4 is etched in a stripe pattern to the GaInP etching stop layer 107, the outermost surface becomes GaInP. Then, the current confinement layer 204 is made of GaInP, GaIn
When formed of a material containing no Al, such as AsP or GaAsP, the surface to be regrown is a material containing no Al. Therefore, the influence of the surface oxidation is reduced, and the second AlGaInP cladding layer 10 of the second conductivity type is formed thereon.
Even when regrowth of No. 8, a decrease in the crystallinity at the interface can be suppressed.

The semiconductor laser device having the configuration shown in FIGS. 7 and 8 can be modified as shown in FIG. That is, in the semiconductor laser device of FIG. 10, the n-type AlInP current confinement layer 601 and the n-type GaAs are formed on the p-type GaInP etching stop layer 107 in the configuration example of FIG.
It is different from the semiconductor laser device shown in FIG. 8 in that the P cap layer 602 is laminated. The method for manufacturing the semiconductor laser device shown in FIG. 10 is the same as the process shown in FIG.

In the semiconductor laser device shown in FIG.
The band gap of the InP current confinement layer 601 is
It is larger than 5. Therefore, light guided in the laser element is not absorbed by the n-type AlInP current confinement layer 601. Therefore, the external differential quantum efficiency of the semiconductor laser can be increased as compared with the structure shown in FIG.

The n-type AlInP current confinement layer 601 has a refractive index of p-type AlGaInP cladding layers 106 and 108.
Is bigger than. Therefore, the light distribution becomes asymmetric outside the groove, and the effective refractive index is lower than that inside the groove. Therefore, a real refractive index difference can be formed in the lateral direction, and the lateral mode can be stabilized.

The n-type GaAsP cap layer 602 functions to prevent the surface of the n-type AlInP current confinement layer 601 from being exposed to air and oxidized.

As described above, in the semiconductor laser device of FIG. 7, FIG. 8 or FIG. 10, the first conductivity type AlGaInP cladding layer 104 having a lattice constant between GaAs and GaP is formed on the semiconductor substrate 101. , GaInA
an sP active layer 105 and a first AlGaIn of the second conductivity type having the same lattice constant as the cladding layer 104 of the first conductivity type.
P cladding layer 106, second conductivity type GaInP etching stop layer 107, first conductivity type current confinement layer 20
4), a step of forming a groove by etching the current constriction layer 204 in a stripe shape up to the etching stop layer 107, and a step of exposing the exposed second conductive type etching stop layer 107 and the first conductive type current. Constriction layer 20
A second conductive type second AlGaInP cladding layer 108 having the same lattice constant as the first conductive type cladding layer 104 is laminated on the first conductive type cladding layer 104.

In the semiconductor laser device of the first, second, third, and fourth configuration examples described above, the first conductive type first A
lGaInP cladding layer 106 and second conductive type second A
An etching stop layer 107 made of GaInP is provided between the substrate and the 1GaInP cladding layer. When chemical etching is performed using a sulfuric acid-based or a mixture of hydrochloric acid and phosphoric acid, the etching rate of AlInP is almost stopped when the GaInP etching stop layer 107 is exposed because the etching rate of GaInP is at least one digit lower than that of AlGaInP. It is possible to do. When chemical etching is performed using a mixture of sulfuric acid, hydrogen peroxide, and water, GaAsP and AlGaAsP are etched, but GaInP is hardly etched. Therefore, the etching of GaAsP and AlGaAsP can be stopped at the GaInP etching stop layer 107.

The GaInP etching stop layer 1
The lattice constant of 07 is set to be substantially the same as that of the cladding layers 106 and 108. Therefore, the layer thickness is several tens nm.
It can be formed as thick as above. Therefore, over-etching beyond the etching stop layer 107 does not occur. Therefore, the etching can be reliably stopped, and the reproducibility and uniformity of the etching depth can be improved.

The lattice constants of the cladding layers 106 and 108 are set so as to be the lattice constant between GaAs and GaP. Ga for lattice matching with normal GaAs
The bandgap wavelength of the InP bulk is 655 nm. In contrast, by bringing the lattice constant closer to the GaP side, the band gap wavelength can be shortened. For example, GaIn lattice matched to GaAs _0.8 P _0.2
The bandgap wavelength of P is 604 nm and GaAs
The band gap wavelength of GaInP lattice-matched to _0.6 P _0.4 is 560 nm. Therefore, the active layer 105 is
nAsP, and the laser oscillation wavelength is 630-80 nm for the red laser.
When the thickness is 660 nm, the band gap of the GaInP etching stop layer 107 is
Larger than. Thus, the etching stop layer 1
07 does not absorb the light emitted from the active layer 105 and can suppress the deterioration of the output characteristics even at the time of high output operation.

In particular, GaAs as the semiconductor substrate 101
Alternatively, when an AlGaInP cladding layer 104 having a lattice constant between GaAs and GaP is formed on a GaP substrate via a buffer layer for eliminating lattice mismatch, G
A GaAsP epitaxial substrate having a GaAsP composition gradient layer formed on an aAs or GaP substrate by a VPE method can be purchased and used. Therefore, there is no need to epitaxially grow a buffer layer for alleviating lattice mismatch on the GaAsP epi-substrate, which facilitates crystal growth. That is, as a method for eliminating lattice mismatch, for example, GaAs
GaAs _y by VPE method on s substrate or GaP substrate
A P _{1 -y} composition gradient layer is formed, and a constant composition G
There is a method of forming an aAsP thick film. Such GaAs
The sP epi substrate is used for visible LEDs and can be purchased. When a purchased GaAsP epi-substrate is used, it is not necessary to epitaxially grow a buffer layer for alleviating lattice mismatch, so that a laser structure can be relatively easily crystal-grown on a GaAsP thick film.

Alternatively, a buffer layer for alleviating lattice distortion may be formed on a GaAs substrate or a GaP substrate by MBE or MOCVD, and a laser structure may be continuously grown thereon. As a buffer layer for relaxing lattice strain, not only a compositionally graded layer but also a strained superlattice buffer layer or a low-temperature buffer layer can be used. By using these, a stacked structure having a low dislocation density and a flat structure can be formed with one crystal growth apparatus.

Further, in the semiconductor laser device of the second configuration example shown in FIG. 4, between the AlGaInP cladding layer 104 of the first conductivity type and the GaInAsP active layer 105,
GaInAsP active layer 105 and first Al of second conductivity type
Optical waveguide layers 201 and 203 made of GaInP having a band gap larger than that of the active layer 105 are provided on one or both of the GaInP cladding layers 106 (both in the example of FIG. 4). GaInP having a lattice constant between GaAs and GaP is GaInAsP.
The band gap is larger and the refractive index is lower than that of the active layer 105. In addition, the AlGaInP cladding layer 10
The band gap is smaller and the refractive index is larger than that of 4,106. Therefore, an SCH structure is formed. Active layer 10
5 is a GaInAsP material, and optical waveguide layers 201 and 203 are G
Since the aInP material is used, the optical waveguide region having a high light density is made of a semiconductor material containing no Al. Therefore, the surface state density caused by Al can be reduced, and the end face degradation can be suppressed. Therefore, it is possible to suppress COD and improve the maximum light output of the red semiconductor laser.

Further, in the semiconductor laser device shown in FIG. 5, on the GaInP etching stop layer 107,
Current constriction layers 204 are buried on both sides of the stripe-shaped current path. Therefore, the current can be narrowed in the vicinity of the active layer 105. Therefore, the spread of the current in the horizontal direction can be suppressed, and the threshold current can be reduced.

By using a material having a different refractive index or absorption coefficient from the cladding layer as the current confinement layer 204, an effective refractive index difference can be formed in the lateral direction. Thereby, a rib waveguide for confining light in the current path can be formed. Accordingly, a semiconductor laser of a refractive index guided type having a stable transverse mode can be operated in a single mode even at a high output.

[0072]

As described above, according to the first aspect of the present invention, at least GaAs is formed on the semiconductor substrate.
Conductivity type AlG having a lattice constant between Ga and GaP
aInP cladding layer, GaInAsP active layer,
A first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the conductivity type;
aInP etching stop layer and second AlG of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type
aInP cladding layer is sequentially laminated, the lattice constant of the etching stop layer is substantially equal to the lattice constant of the cladding layer of the first conductivity type, and the band gap of the etching stop layer is larger than the band gap of the active layer. Since GaInP having high etching selectivity is used for the etching stop layer and is substantially lattice-matched with the cladding layer, the thickness of the etching stop layer can be increased. Therefore, the controllability of stopping the etching is enhanced. Further, the band gap wavelength of the GaInP etching stop layer is set to 620 nm.
Since the wavelength can be shortened as follows, light of a red laser having a wavelength of 630 to 680 nm is not absorbed. Therefore, it is possible to reduce the characteristic deterioration during the high output operation.

According to the second aspect of the present invention, Ga
An AlGaInP cladding layer of a first conductivity type having a lattice constant between GaAs and GaP, a GaInAsP active layer, and a first conductive layer on an As or GaP substrate via a buffer layer for eliminating lattice mismatch. AlG of the second conductivity type having the same lattice constant as the cladding layer of the first type
an aInP cladding layer, a second conductivity type GaInP etching stop layer, and a second conductivity type second AlGaInP cladding layer having the same lattice constant as the first conductivity type cladding layer are sequentially laminated. The lattice constant of the layer is substantially equal to the lattice constant of the cladding layer of the first conductivity type, and the band gap of the etching stop layer is larger than the band gap of the active layer. In addition, GaAs or G
A GaAsP epitaxial substrate in which a GaAsP composition gradient layer is formed on an aP substrate by a VPE method can be purchased and used. Therefore, there is no need to epitaxially grow a buffer layer for alleviating lattice mismatch on the GaAsP epi-substrate, which facilitates crystal growth.

Alternatively, a buffer layer for alleviating lattice distortion may be formed on a GaAs or GaP substrate by MBE or MOCVD, and an LD laminated structure may be continuously grown on the buffer layer. In this case,
A stacked structure can be formed with one crystal growth apparatus.

According to the third aspect of the present invention, in the semiconductor laser device according to the first or second aspect, the first conductivity type AlGaInP cladding layer and the GaIn
An optical waveguide layer made of GaInP having a larger band gap than the active layer is provided between the AsP active layer and one or both of the GaInAsP active layer and the first AlGaInP clad layer of the second conductivity type. The GaInAsP material is used for the active layer and the GaInP material is used for the optical waveguide layer. The optical waveguide region with high optical density is made of a semiconductor material that does not contain Al, so that the surface state density caused by Al is reduced. As a result, end face deterioration can be suppressed. Therefore, in addition to the effects of claims 1 and 2, COD
And the maximum light output of the red semiconductor laser can be improved.

According to a fourth aspect of the present invention, in the semiconductor laser device according to any one of the first to third aspects, the GaInP etching stop layer has
A current confinement layer is buried on both sides of the stripe-shaped current path, and by burying the current confinement layer inside, a current can be confined near the active layer. Therefore, in addition to the functions and effects of the first, second, and third aspects, the spread of the current in the horizontal direction can be suppressed, and the threshold current can be reduced.

Since the current confinement layer has a different refractive index or absorption coefficient from the cladding layer, it forms a rib waveguide for confining light in a current path. Therefore, the transverse mode becomes a stable refractive index waveguide type, and can be operated in a single mode even at a high output.

According to a fifth aspect of the present invention, in the semiconductor laser device according to the fourth aspect, the current confinement layer has a band gap larger than that of the active layer, and has a second band gap.
The refractive index is smaller than that of the conductive type AlGaInP cladding layer. By making the band gap of the current confinement layer larger than that of the active layer, light absorption in the current confinement layer can be suppressed. Therefore, in addition to the effect of the fourth aspect, the external differential quantum efficiency of the semiconductor laser is increased, and higher output operation is possible.

According to the invention of claim 6, on the semiconductor substrate, at least a first conductivity type AlGaInP cladding layer having a lattice constant between GaAs and GaP, a GaInAsP active layer, and a first conductive type. AlGaI of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type
sequentially stacking an nP cladding layer, a second conductivity type GaInP etching stop layer, and a second conductivity type second AlGaInP cladding layer having the same lattice constant as the first conductivity type cladding layer; Second AlGa of conductivity type
A step of forming a ridge stripe structure by striping the InP cladding layer up to the etching stop layer to form a ridge stripe structure; and forming a current constriction of the first conductivity type on both sides of the striped second cladding layer of the second conductivity type. A step of selectively embedding the layer and a step of laminating a contact layer of the second conductivity type on the etching stop layer of the second conductivity type and the current confinement layer of the first conductivity type. It becomes possible to manufacture the semiconductor laser devices of items 4 and 5. At this time, since the contact area between the p-side electrode and the p-type contact layer can be increased, the contact resistance can be reduced. Therefore, the operating voltage of the device can be reduced.

According to the seventh aspect of the present invention, at least a first conductivity type AlGaInP cladding layer having a lattice constant between GaAs and GaP, a GaInAsP active layer, The first AlGaI of the second conductivity type having the same lattice constant as the cladding layer of the conductivity type
a step of sequentially laminating an nP cladding layer, a second conductivity type GaInP etching stop layer, and a first conductivity type current confinement layer, and forming a groove by etching the current confinement layer in a stripe shape up to the etching stop layer. And a second AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type on the exposed etching stop layer of the second conductivity type and the current confinement layer of the first conductivity type. And the same structure can be formed by reducing the number of times of crystal growth by one as compared with the manufacturing method according to the sixth aspect. Therefore, the manufacturing process is simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first configuration example of a semiconductor laser device according to the present invention.

FIG. 2 is a diagram showing a more specific configuration example of the semiconductor laser device of FIG. 1;

FIG. 3 is a diagram showing a specific example of the semiconductor laser device of FIGS. 1 and 2;

FIG. 4 is a diagram showing a second configuration example of the semiconductor laser device according to the present invention.

FIG. 5 is a diagram showing a third configuration example of the semiconductor laser device according to the present invention.

6 is a diagram showing a specific example of a manufacturing process example of the semiconductor laser device of FIG. 5;

FIG. 7 is a diagram showing a fourth configuration example of the semiconductor laser device according to the present invention.

8 is a diagram showing a more specific configuration example of the semiconductor laser device of FIG. 7;

FIG. 9 is a diagram illustrating an example of a manufacturing process of the semiconductor laser device of FIG. 8;

FIG. 10 is a diagram showing a modification of the semiconductor laser device having the configuration example of FIGS. 7 and 8;

FIG. 11 is a view showing a conventional semiconductor laser.

FIG. 12 is a view showing a conventional semiconductor laser.

[Explanation of symbols]

Reference Signs List 1 n-type GaAs substrate 2 n-type buffer layer 3 n-type AlGaInP cladding layer 4 multiple quantum well active layer 5 p-type AlGaInP cladding layer 5A first cladding layer 5B second cladding layer 6 p-type GaAs cap layer 7 groove 8n Type GaAs current confinement layer 9 nGaInP etching stop layer 11 n-type GaAs substrate 12 n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 13 a first p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 13 b 2 p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 14 n-type GaAs current blocking layer 15 p-type GaAs cap layer 16 undoped Ga _0.5 In _0.5 P active layer 17 etching stopper layer 18 n-side electrode 19 p-side electrode Reference Signs List 101 semiconductor substrate 102 composition gradient layer 103 buffer layer 104 first conductivity type cladding layer 1 5 active layer 106 first second conductivity type cladding layer 107 etch stop layer 108 second second conductivity type cladding layer 109 spike preventing layer 110 contact layer 111 SiO ₂ insulating layer 112 p-side electrode 113 n-side electrode 201 lower photoconductive Wave layer 203 Upper optical waveguide layer 204 Current confinement layer 301 SiO ₂ mask layer 501 SiO ₂ mask layer 601 Current confinement layer 602 Cap layer

Continued on the front page (72) Inventor Naoto Shakuya 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 5F073 AA13 AA20 AA45 AA53 AA74 BA06 CA07 CA17 CB02 CB07 CB08 EA28

Claims (7)

[Claims] At least GaAs is formed on a semiconductor substrate.
Conductivity type AlG having a lattice constant between Ga and GaP
aInP cladding layer, GaInAsP active layer,
A first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the conductivity type;
aInP etching stop layer and second AlG of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type
aInP cladding layers are sequentially stacked, the lattice constant of the etching stop layer is substantially equal to the lattice constant of the first conductivity type cladding layer, and the band gap of the etching stop layer is larger than the band gap of the active layer. A semiconductor laser device characterized by the above-mentioned. 2. At least a Ga or GaP substrate is provided on a GaAs or GaP substrate via a buffer layer for eliminating lattice mismatch.
A of the first conductivity type having a lattice constant between As and GaP
an lGaInP cladding layer, a GaInAsP active layer,
A first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type, a GaInP etching stop layer of the second conductivity type, and having the same lattice constant as the cladding layer of the first conductivity type. Second A of second conductivity type
1GaInP cladding layers are sequentially laminated, the lattice constant of the etching stop layer is substantially equal to the lattice constant of the cladding layer of the first conductivity type, and the band gap of the etching stop layer is larger than the band gap of the active layer. A semiconductor laser device characterized by the above-mentioned. 3. The semiconductor laser device according to claim 1, wherein GaInAsP is located between the first conductivity type AlGaInP cladding layer and the GaInAsP active layer.
A semiconductor characterized in that an optical waveguide layer made of GaInP having a larger band gap than the active layer is provided on one or both of the active layer and the first AlGaInP clad layer of the second conductivity type. Laser device. 4. The semiconductor laser device according to claim 1, wherein a current confinement layer is embedded on both sides of the GaInP etching stop layer with a stripe-shaped current path interposed therebetween. A semiconductor laser device. 5. The semiconductor laser device according to claim 4, wherein the current confinement layer has a larger band gap than the active layer and has a smaller refractive index than the AlGaInP cladding layer of the second conductivity type. Semiconductor laser device. 6. At least GaAs is formed on a semiconductor substrate.
Conductivity type AlGa having a lattice constant between Ga and GaP
An InP cladding layer, a GaInAsP active layer, a first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type, and a Ga of the second conductivity type.
An InP etching stop layer and a second AlGa of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type.
A step of sequentially laminating an InP cladding layer; a step of forming a second ridge stripe structure by etching the second AlGaInP cladding layer of the second conductivity type up to an etching stop layer; and a step of forming a second ridge stripe structure. Selectively embedding a first-conduction-type current confinement layer on both sides of the second-conductivity-type second cladding layer; Laminating a two-conductivity-type contact layer. 7. At least GaAs is formed on a semiconductor substrate.
Conductivity type AlG having a lattice constant between Ga and GaP
aInP cladding layer, GaInAsP active layer,
A first AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the conductivity type;
a step of sequentially laminating an aInP etching stop layer and a current confinement layer of a first conductivity type; a step of forming a groove by etching the current confinement layer in a stripe shape to an etching stop layer; Laminating a second AlGaInP cladding layer of the second conductivity type having the same lattice constant as the cladding layer of the first conductivity type on the etching stop layer and the current confinement layer of the first conductivity type. A method for manufacturing a semiconductor laser device, comprising: