JP3472739B2 - Manufacturing method of semiconductor laser - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor laser, and more particularly to a digital versatile disk (DV).
D) A method for manufacturing a visible light semiconductor laser used as a light source for an optical disc such as a magneto-optical (MO) disc.

[0002]

2. Description of the Related Art In recent years, a high-density optical disk device using an AlGaInP-based visible light semiconductor laser as a light source has been actively developed, and it has been strongly desired to increase the output of the AlGaInP-based visible light semiconductor laser as a light source. There is. However, the AlGaInP-based material has the drawbacks of high thermal resistance and low end face instantaneous destruction light density (COD). Therefore, by increasing the band gap of the active layer near the end face, C
Several window structure semiconductor lasers that increase the OD density have been reported. For example, JP-A-3-208388
Issue, IEEE Journal of Quantum Electronics, 29 by Arimoto,
1874 (1993), Ueno et al., Japanese Journal of Applied Physics, 29, L1666 (1990). In all of these examples, the bandgap is increased by diffusing Zn impurities only in the window portion near the end face and disordering the natural superlattice or making the multiple quantum well (MQW) active layer mixed crystal. , Window structure is made. In these Zn diffusion type window structures, since it is necessary to increase the band gap only in the portion that becomes the window portion near the end face,
It is necessary to carry out selective diffusion of. Therefore, in all of these conventional examples, a selective diffusion mask is formed by forming a dielectric mask as a selective diffusion mask on the double hetero structure and then performing a heat treatment using a ZnO film or ZnAs ₂ as a diffusion source. . Further, these conventional Zn diffusion type window structures are manufactured by crystal growth three times.

FIG. 3 shows a conventional Zn diffusion type window structure A.
The manufacturing process figure of 1GaInP system visible light semiconductor laser is shown. In the conventional window structure AlGaInP-based visible light semiconductor laser, first, n-G is formed on the n-GaAs substrate 200.
The aAs buffer layer 170, the n-AlGaInP cladding layer 130, the MQW active layer 110, the p-AlGaInP inner cladding layer 120, the p-GaInP etching stopper layer 140, the p-AlGaInP outer cladding layer 150, and the p-GaInP heterobuffer layer 160 are sequentially formed. A double hetero structure is produced by crystal growth. afterwards,
As a Zn selective diffusion mask, a SiN _x film 230 is formed by patterning so as to remove a portion corresponding to the cavity end face, and a ZnO film 250 and a SiO ₂ film 220 are formed thereon. Next, heat treatment is performed at 600 ° C. to diffuse Zn only in the portion corresponding to the end face of the cavity to form the Zn diffusion region 2
40 to form a window structure (FIG. 3).
(A)). Then, the SiN _x film 230 and the ZnO film 25
0, after removing the SiO ₂ film 220, a stripe-shaped SiN _x film 230 is formed on the double hetero structure, and the p-GaInP etching stopper layer 140 is etched using the SiN _x film 230 as a mask to form the p- A
A ridge waveguide is formed in the 1GaInP outer cladding layer 150 (FIG. 3B). Next, the SiN _x film 230 on the cavity end face equivalent portion is removed (FIG. 3C), and n-GaA is formed on the outside of the ridge waveguide side and on the cavity end face equivalent portion.
The s block layer 180 is grown (FIG. 3D). Finally, after growing the p-GaAs contact layer 190 on the entire surface, the back surface of the substrate is polished to form electrodes (p electrode 290, n electrode 3).
00), cleavage, formation of an end face protective film, and the like, a conventional window structure AlGaInP-based visible light semiconductor laser as shown in FIG.

[0004]

However, these conventional examples have a problem that the steps are complicated as follows. That is, it is necessary to form a SiN _x film as a selective diffusion mask for Zn diffusion, a patterning process, and a SiN _x film for selective growth.
Further, a heat treatment process for Zn diffusion is required. Furthermore, Z
The Zn diffusion front position and the doping profile are changed by being subjected to the second thermal history of performing the second and third growth at the same temperature as that of the Zn diffusion heat treatment after the n diffusion heat treatment, and the characteristics are excellent. There is a problem that the device cannot be obtained with a high yield.

The object of the present invention is to provide a Zn-diffused window structure AlG having excellent characteristics easily without requiring a complicated process.
It is to provide an aInP-based visible light semiconductor laser device with a high yield.

[0006]

According to the present invention, a first conductivity type clad layer, an active layer having a bandgap smaller than that of the clad layer, and a second bandgap having a bandgap larger than that of the active layer are provided on a first conductivity type semiconductor substrate. A first crystal growth step of producing a double heterostructure by crystal growth, which includes at least a conductivity type clad layer and a second conductivity type semiconductor layer in which a diffusion rate of Zn is slower than that of the second conductivity type clad layer; A step of removing only a part corresponding to the light emitting end face of the two-conductivity type semiconductor layer, and a ZnO film on the entire surface of the double hetero structure,
A step of sequentially forming a dielectric film, a step of patterning the ZnO film and the dielectric film in a stripe shape, and a step of etching the double hetero structure by using the patterned ZnO film and the dielectric film as a mask to form a ridge conductor. A step of forming a waveguide and a second crystal growth step of selectively growing a current blocking layer using the patterned ZnO film and the dielectric film as a selective growth mask and simultaneously diffusing Zn of the ZnO film to form a window structure. A method for manufacturing a semiconductor laser, comprising at least: further,
It is also a feature of the present invention that it has a step of patterning / forming a dielectric film on the end face window portion to form an end face current non-injection portion, and is manufactured by two crystal growth steps.

A further manufacturing method of the present invention is a first conductivity type clad layer on a first conductivity type semiconductor substrate, an active layer having a band gap smaller than that of the clad layer, and a second conductivity type having a band gap larger than that of the active layer. A first crystal growth step of forming a double heterostructure by crystal growth, which includes at least a second-conductivity-type cladding layer and a second-conductivity-type semiconductor layer in which the diffusion rate of Zn is slower than that of the second-conductivity-type cladding layer; A step of removing only a part corresponding to the light emitting end face of the conductive type semiconductor layer, and ZnO on the entire surface of the double hetero structure.
A step of sequentially forming a film and a dielectric film, a step of patterning the ZnO film and the dielectric film in a stripe shape, and an etching of the double hetero structure using the patterned ZnO film and the dielectric film as a mask. A step of forming a ridge waveguide and a second crystal growth in which a current blocking layer is selectively grown using the patterned ZnO film and the dielectric film as a selective growth mask and at the same time Zn of the ZnO film is diffused to form a window structure. A step of exposing the surface of the light emitting end face portion of the second conductivity type cladding layer forming the ridge waveguide, and removing the ZnO film and the dielectric film, and then exposing the second conductivity type contact layer on the entire surface. And a third crystal growing step of growing a crystal.

In the above manufacturing method, the current blocking layer has a laminated structure of a first conductive type semiconductor layer, a high resistance semiconductor layer, a semi-insulating semiconductor layer, and a first conductive type semiconductor layer and a second conductive type semiconductor layer. A structure having a pn junction is used to form the semiconductor layer. In addition, specific semiconductor materials for the current blocking layer include GaAs, AlGaAs, and AlA.
s, AlInP, undoped AlInP, AlGaIn
It is preferable to use any one of P, undoped AlGaInP, and GaInP, or a combination of these semiconductors. Further, AlGaInP is used for the clad layer, a semiconductor layer in which the diffusion rate of Zn is slower than that of the clad layer, that is, GaAs for the contact layer or cap layer formed on the clad layer, SiO ₂ or SiN _{x for} the dielectric film, and a semiconductor substrate. For GaAs, and GaInP, AlGaInP, G for the active layer
It is preferable to use either aInAs or AlGaInAs.

(Operation) Zn of the first embodiment of the present invention
FIG. 1 is a manufacturing process diagram of a diffusion type window structure AlGaInP-based visible light semiconductor laser, and FIG. 2 is a manufacturing process diagram of a Zn diffusion type window structure AlGaInP-based visible light semiconductor laser according to a second embodiment of the present invention. FIG. 3 shows a manufacturing process diagram of the Zn diffusion type window structure AlGaInP-based visible light semiconductor laser of FIG. With reference to these drawings, the operation and effect of the semiconductor laser manufacturing method of the present invention will be described by taking the Zn diffusion window structure AlGaInP-based visible light semiconductor laser manufacturing method as an example.

Zn diffusion type window structure AlG of the present invention
In the method of manufacturing an aInP-based visible light semiconductor laser, p-GaI is used as a Zn selective diffusion mask instead of the SiN _x film selective diffusion mask used in the conventional method of manufacturing an AlGaInP-based visible light semiconductor laser of Zn diffusion type window structure.
A p-GaAs contact layer or a p-GaAs cap layer formed on the p-AlGaInP clad layer via the nP heterobuffer layer is used. GaAs is AlG
The Zn diffusion rate is 10 times or more slower than that of aInP. Therefore, the diffusion depth of Zn can be controlled by etching the portion of the p-GaAs contact layer (or the p-GaAs cap layer) corresponding to the cavity end face and controlling the thickness thereof, which corresponds to the cavity end face having a small layer thickness. It is possible to diffuse Zn only in the portion to the n-AlGaInP cladding layer. This eliminates the need for the SiN _x film forming and patterning process to be the Zn selective diffusion mask. Further, in the method for manufacturing a Zn diffusion window structure AlGaInP-based visible light semiconductor laser of the present invention, a ZnO film serving as a diffusion source, S
The iO ₂ film is used for Zn diffusion and at the same time used as a selective growth mask. This is possible by combining heat treatment for Zn diffusion and selective growth. Both the heat treatment temperature for Zn diffusion and the selective growth temperature are about 600 ° C. Therefore, the Zn diffusion front (Zn diffusion depth) can be controlled by the thickness of the p-GaAs contact layer (or p-GaAs cap layer). This eliminates the need for a heat treatment step for Zn diffusion and a step of forming a SiN _x film selective growth mask after Zn diffusion, as in the conventional method for manufacturing a Zn diffusion type window structure AlGaInP-based visible light semiconductor laser. Becomes Further, the Zn diffusion type window structure AlGa according to the first embodiment of the present invention is used.
The InP-based visible light semiconductor laser is manufactured by two growth processes, that is, growth of a double hetero structure and selective growth of a current block layer (which also serves as heat treatment for Zn diffusion).
Therefore, the conventional Zn diffusion type window structure AlGaI
As in the method for manufacturing an nP-based visible light semiconductor laser, the Zn diffusion heat treatment is performed, and then the selective growth of the current blocking layer is performed.
-No double thermal history of full-face growth of GaAs contact layer. Therefore, the Zn diffusion front position and the doping profile can be easily controlled, and the occurrence of defective elements can be prevented. Also, in the Zn diffusion type window structure AlGaInP-based visible light semiconductor laser of the second embodiment of the present invention, since the selective growth of the current block layer and the heat treatment for Zn diffusion are combined, a double hetero structure is formed. Crystal growth, selective growth of the current blocking layer, and overall growth of the p-GaAs contact layer.
The thermal history after Zn diffusion is only the entire surface growth of the p-GaAs contact layer, though it is produced by the single growth.
As in the conventional method for manufacturing a Zn diffusion type window structure AlGaInP-based visible light semiconductor laser, the Zn diffusion heat treatment is performed, and then the current block layer is selectively grown and p-GaAs is grown.
It does not undergo the double thermal history of contact layer overgrowth. Therefore, the Zn diffusion front position and the doping profile are easier to control as compared with the conventional method of manufacturing the AlGaInP-based visible light semiconductor laser of Zn diffusion type window structure, and the occurrence of defective elements can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a manufacturing process diagram of a window structure AlGaInP-based visible light semiconductor laser according to a first embodiment of the present invention. The first embodiment of the present invention will be described below with reference to these drawings.

Although a metal organic chemical vapor deposition (MOVPE) method is used as the growth method and an AlGaInP-based crystal material is used as the crystal material, the same applies to other crystal growth methods and crystal materials. Hereinafter, the device manufacturing steps will be sequentially described. An n-GaAs substrate 200 is used as the semiconductor substrate of the present invention. Each semiconductor layer is formed on this semiconductor substrate by M
Crystals are sequentially grown by the OVPE method to form a double hetero structure. The structure of the double hetero structure is as follows. An n-GaAs buffer layer 170 having a thickness of 0.3 μm,
N- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P with a thickness of 1.5 μm
Cladding layer 130, MQW active layer 110, thickness 0.3 μ
m p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 1
20, p-Ga _0.5 In _0.5 P etching stopper layer 140 having a thickness of 0.01 μm, p- (Al having a thickness of 1.2 μm
_0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 150, n-Ga
_0.5 In _0.5 P heterobuffer layer 160, thickness 0.5 μm
P-GaAs contact layer 190 of FIG. Next, a dielectric film is formed on the p-GaAs contact layer 190 except for the portion corresponding to the cavity end face, and this dielectric film is used as an etching mask to etch the portion of the p-GaAs corresponding to the cavity end face. Contact layer 190 has a thickness of 0.3
Remove μm. Then, after removing the dielectric film, the ZnO film 250 and the SiO ₂ film 220 are sputtered to form p-GaAs.
It is formed on the contact layer 190 (FIG. 1A), and [-110] for forming a ridge waveguide for controlling the transverse mode.
Direction, the ZnO film 250, SiO is etched by using a stripe-shaped mask having a stripe width of 5 μm.
_{2 The} film 220 is patterned into stripes (see FIG. 1).
(B)). This stripe-patterned Z
Using the nO film 250 and the SiO ₂ film 220 as an etching mask, the p-GaAs contact layer 190 and p-Ga _0.5
In _0.5 P hetero buffer layer 160, p- (Al _0.7 Ga
_0.3 ) _0.5 In _0.5 P Clad layer 150 is etched,
A mesa stripe is formed (FIG. 1 (c)). Then, the striped ZnO film 250 and the SiO ₂ film 2 are further formed.
N-GaAs block layer 1 using 20 as a selective growth mask
80 is selectively grown on both sides of the mesa stripe at a growth temperature of 600 ° C. (FIG. 1D). At that time, Zn in the ZnO film 250 is n- (Al _0.7 Ga _0.3 ) in the portion where the p-GaAs contact layer 190 corresponding to the cavity end face is partially removed.
_{Diffuses into the 0.5} In _0.5 P clad layer 130. on the other hand,
The Zn diffusion front in the portion other than the cavity end face equivalent portion is
A Zn diffusion region 240 in the p-GaAs contact layer 190 is formed. Next, the ZnO film 250, SiO ₂
The film 220 is removed. Then, in order to manufacture the end face current non-injection structure, the SiO ₂ film 220 is newly formed and patterned in a portion corresponding to the end face (window portion) of the resonator. Then, the back surface of the substrate is polished, and the p-electrode 290 is formed by p-G
aAs contact layer 190, n-GaAs block layer 1
80, and formed over the SiO ₂ film 220, and n−
An n-electrode 300 is formed on the back surface of the GaAs substrate. After this,
The Zn diffusion window structure semiconductor laser of the present invention shown in FIG. 1E can be manufactured through the cleavage step and the end face protective film forming step (the end face protective film is not shown).

The semiconductor laser of the present embodiment has a characteristic as a window structure semiconductor laser which is not humble as compared with the conventional one, and C
High output was obtained until OD did not occur and thermal saturation occurred.

(Second Embodiment) Next, the second embodiment of the present invention will be described.
FIG. 2 is a manufacturing process drawing of the window structure AlGaInP-based visible light semiconductor laser of the above embodiment. The second embodiment of the present invention will be described below with reference to FIG.

Although a metal organic vapor phase epitaxy (MOVPE) method is used as the growth method and an AlGaInP system is used as the crystal material, the same applies to other crystal growth methods and crystal materials. First, the device manufacturing steps will be sequentially described. The semiconductor substrate of the present invention includes an n-GaAs substrate 20.
0 is used. On this n-GaAs substrate, the semiconductor layers are sequentially crystal-grown by the MOVPE method to form a double hetero structure. The structure of the double hetero structure is as follows. An n-GaAs buffer layer 170 having a thickness of 0.3 μm,
N- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P with a thickness of 1.5 μm
Cladding layer 130, MQW active layer 110, thickness 0.3 μ
m p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 1
20, p-Ga _0.5 In _0.5 P etching stopper layer 140 having a thickness of 0.01 μm, p- (Al having a thickness of 1.2 μm
_0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 150, n-Ga
_0.5 In _0.5 P heterobuffer layer 160, thickness 0.5 μm
P-GaAs cap layer 210 of FIG. Next, the portion of the p-GaAs cap layer 210 corresponding to the cavity end face is removed with a thickness of 0.3 μm using a mask. Then, a ZnO film 250 and a SiO ₂ film 220 are formed by sputtering (FIG. 2A), and a stripe width of 5 μm extending in the [−110] direction for forming a ridge waveguide for controlling the transverse mode.
ZnO film 250, Si using a striped mask of m
The O ₂ film 220 is patterned in a stripe shape (FIG. 2B). This striped ZnO film 250, Si
Using the O ₂ film 220 as an etching mask, p-GaAs
The cap layer _{210, p-Ga 0.5 In 0.5} P hetero buffer layer _{160, p- (Al 0.7 Ga 0} .3) 0.5 In 0.5 P cladding layer 150 is etched to form a mesa stripe (FIG. 2 (c)). And Zn in stripes
Using the O film 250 and the SiO ₂ film 220 as a selective growth mask,
The n-GaAs block layer 180 is selectively grown on both sides of the mesa stripe at a growth temperature of 600 ° C. (FIG. 2D). At that time, the p-GaAs cap layer 21 corresponding to the cavity end face is formed.
In the portion where 0 is partially removed, the p-GaAs cap layer 2
Since the thickness of 10 is thin, Zn of the ZnO film 250 is n−.
(Al _0.7 Ga _{0 .3)} diffused to in _0.5 an In _0.5 P cladding layer 130, Zn diffusion front is in the p-GaAs contact layer 190 in a portion other than the cavity end face corresponding portions, Z
An n diffusion region 240 is formed. Next, in order to fabricate a structure for injecting no current into the end surface, Zn is n
-(Al _0.7 Ga _0.3 ) _0.5 In _0.5 P The ZnO film 250 and the SiO ₂ film 220 on the upper end face diffused into the clad layer 130 are removed, and the remaining ZnO film 250 and the SiO ₂ film 2 are removed.
20 as an etching mask, p− of the end face Zn diffusion part
GaAs cap layer 210 and p-Ga _0.5 In _0.5 P
The hetero buffer layer 160 is removed. Then, after removing the ZnO film 250 and the SiO ₂ film 220, a p-GaAs contact layer 190 having a thickness of 3 μm is grown on the entire surface. After that, the back surface of the n-GaAs substrate is polished to form a p-electrode 290 on the p-GaAs contact layer 190, and n-Ga is formed.
An n-electrode 300 is formed on the back surface of the As substrate. After that, the Zn diffusion window structure semiconductor laser of the present invention shown in FIG. 2E can be manufactured through a cleavage step and an end face protective film forming step (the end face protective film is not shown).

Also in the case of the second embodiment, the characteristics as the window structure semiconductor laser are not humble as compared with the conventional one, and C
High output was obtained until OD did not occur and thermal saturation occurred.

[0017] Also in the above-described one embodiment, the active layer is MQW active layer _{(e.g., (Al 0. 7 Ga 0.3)} 0.5 In
_{A structure in which a 0.5} P barrier layer and a Ga _0.5 In _0.5 P well layer are alternately laminated can be used. However, a periodic composition fluctuation of In and Ga during crystal growth, that is, a so-called natural superlattice is generated. Formed active layer, eg undoped G
a _0.5 In _0.5 P natural superlattice active layer, (Al _z Ga _{1 -z} )
_It may be a _0.5 In _0.5 P natural superlattice active layer (0 <z ≦ 0.2). As the active layer material, GaInP, AlGaI
nP, GaInAs, AlGaInAs, etc. can be used. Further, another active layer material, for example, a crystal material of an infrared semiconductor laser may be used.

Although n-GaAs was used for the current blocking layer, n-AlGaAs, n-AlAs, and n-AlIn were used.
P, n-AlGaInP, n-GaInP, high-resistance semiconductor layer undoped AlInP, undoped AlGa
InP, a semiconductor layer formed of a combination of these semiconductor layers, or a semiconductor layer having a pn junction may be used.

[0019]

According to the manufacturing method of the present invention, since Zn is diffused during growth of the block layer, a Zn diffusion type window structure semiconductor laser can be easily manufactured without requiring a complicated process. In addition, Z is more than the block layer
By controlling the thickness of a portion of the semiconductor layer having a low n-diffusion rate (corresponding to the GaAs contact layer and the GaAs cap layer of the embodiment) corresponding to the cavity end face, the diffusion depth of Zn diffused to the cavity end is controlled. Can be controlled easily. Furthermore, Z
After n-diffusion, there is no regrowth step at a temperature similar to or higher than that during Zn diffusion, or the number of regrowths is smaller than before, so the Zn diffusion front position and doping profile can be controlled. A semiconductor laser that can be easily manufactured and has excellent characteristics can be manufactured with a high yield.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a Zn diffusion window structure AlGaInP-based visible light semiconductor laser according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a Zn diffusion type window structure AlGaInP-based visible light semiconductor laser according to a second embodiment of the present invention.

FIG. 3 Conventional Zn diffusion type window structure AlGa
FIG. 6 is a manufacturing process diagram of an InP-based visible light semiconductor laser.

[Explanation of symbols]

110 MQW active layer 120 p-AlGaInP inner clad layer 130 n-AlGaInP clad layer 140 p-GaInP etching stopper layer 150 p-AlGaInP outer clad layer 160 p-GaInP hetero buffer layer 170 n-GaAs buffer layer 180 n-GaAs block layer 190 p-GaAs contact layer 200 n-GaAs substrate 210 p-GaAs cap layer 220 SiO ₂ film 230 SiN _x film 240 Zn diffusion region 250 ZnO film 290 p electrode 300 n electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-145553 (JP, A) JP-A-2000-31596 (JP, A) JP-A-4-84482 (JP, A) JP-A-9-275241 (JP, A) JP-A 1-166590 (JP, A) JP-A 10-290043 (JP, A) JP-A 2000-22262 (JP, A) JP-A 5-167186 (JP, A) Japanese Patent Laid-Open No. 9-23037 (JP, A) Japanese Patent Laid-Open No. 2-203585 (JP, A) Japanese Patent Laid-Open No. 5-152671 (JP, A) Japanese Patent Laid-Open No. 12-323788 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H01S 5/00-5/50

Claims (7)

(57) [Claims] 1. A first conductive type clad layer, an active layer, a second conductive type clad layer, and a second conductive type having a slower diffusion rate of Zn than the second conductive type clad layer on a first conductive type semiconductor substrate. A first crystal growth step of forming a double hetero structure including at least a semiconductor layer of the second conductivity type by crystal growth; a step of removing only a part or all of a portion corresponding to the light emitting end face of the second conductivity type semiconductor layer; ZnO all over the structure
A step of sequentially forming a film and a dielectric film, a step of patterning the ZnO film and the dielectric film in a stripe shape, and an etching of the double hetero structure using the patterned ZnO film and the dielectric film as a mask. A step of forming a ridge waveguide and a second crystal growth in which a current blocking layer is selectively grown using the patterned ZnO film and the dielectric film as a selective growth mask and at the same time Zn of the ZnO film is diffused to form a window structure. A method for manufacturing a semiconductor laser, comprising at least a step. 2. The method includes at least a step of patterning and forming a dielectric film on an end face window portion to form an end face current non-injection portion, and the step is performed by two crystal growth steps. 1. The method for manufacturing a semiconductor laser according to 1. 3. A first conductivity type clad layer, an active layer, a second conductivity type clad layer, and a second conductivity type having a slower diffusion rate of Zn than the second conductivity type clad layer on a first conductivity type semiconductor substrate. A first crystal growth step of forming a double hetero structure including at least a semiconductor layer of the second conductivity type by crystal growth; a step of removing only a part or all of a portion corresponding to the light emitting end face of the second conductivity type semiconductor layer; ZnO all over the structure
A step of sequentially forming a film and a dielectric film, a step of patterning the ZnO film and the dielectric film in a stripe shape, and an etching of the double hetero structure using the patterned ZnO film and the dielectric film as a mask. A step of forming a ridge waveguide and a second crystal growth in which a current blocking layer is selectively grown using the patterned ZnO film and the dielectric film as a selective growth mask and at the same time Zn of the ZnO film is diffused to form a window structure. A step of exposing the surface of the light emitting end face portion of the second conductivity type cladding layer forming the ridge waveguide, and removing the ZnO film and the dielectric film, and then exposing the second conductivity type contact layer on the entire surface. 3. A method for manufacturing a semiconductor laser, comprising at least a third crystal growing step of growing a crystal. 4. The method of manufacturing a semiconductor laser according to claim 1, wherein the clad layer is AlGaInP, and the semiconductor layer in which the diffusion rate of Zn is slower than that of the clad layer is GaAs. 5. The method for manufacturing a semiconductor laser according to claim 1, wherein the dielectric film is SiO ₂ or SiN _x. 6. The current blocking layer is GaA of the first conductivity type.
s, a first conductivity type AlGaAs, a first conductivity type AlAs, a first conductivity type AlInP, an undoped AlInP, a first conductivity type AlGaInP, an undoped AlGaInP, a first conductivity type GaInP, or a semiconductor layer of any of these semiconductors. It is a combination, It is characterized by the above-mentioned.
6. The method for manufacturing a semiconductor laser according to any one of 5 above. 7. The semiconductor substrate is GaAs and the active layer is GaI.
nP, AlGaInP, GaInAs, or AlG
It contains any of aInAs, The claim 1 characterized by the above-mentioned.
7. The method for manufacturing a semiconductor laser according to any one of 6.