JP2944312B2 - Method for manufacturing semiconductor laser device - 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 device having a refractive index waveguide structure.

[0002]

2. Description of the Related Art In recent years, semiconductor laser devices have been widely used as light sources for recording and reading in optical information processing systems such as optical disks and magneto-optical recording disks. Among them, in order to highly functional system, lattice matched to the GaAs substrate _{(Al x Ga 1-x)} 0. 5 In 0. 5 P crystal (0 ≦ x ≦ 1)
The refractive index guided semiconductor laser device, which is made to oscillate in a short wavelength region (600 nm band) by growing a laser diode, has attracted attention.

[0003] A refractive index guided semiconductor laser device generally has an element structure as shown in FIG. That is, on the first conductivity type GaAs substrate 1, a first conductivity type GaAs buffer layer 2, a first conductivity type GaInP buffer layer 3, a first conductivity type AlGaInP cladding layer 4, a GaInP active layer 5, a second conductivity type AlGaInP cladding. Layer 6, second conductivity type GaIn
A P intermediate layer 9 and a second conductivity type GaAs contact layer 10 are stacked in this order. The AlGaInP cladding layer 6, the GaInP intermediate layer 9, and the GaAs contact layer 10 form a stripe-shaped mesa portion 35. The first conductivity type GaAs current blocking layer 11 is formed so as to fill both sides of the stripe-shaped mesa portion 35. Is provided. Furthermore, Ga
An electrode 12 is provided on the As contact layer 10 and the GaAs current blocking layer 11, while an electrode 13 is provided on the back surface of the substrate 1.

A method for growing an AlGaInP crystal on a GaAs substrate includes composition / film thickness controllability, interface steepness, p
The MBE (Molecular Beam Epitaxy) method and the MOCVD (Metal Organic Chemical Vapor Deposition) method, which have excellent doping efficiency and safety, are expected.

[0005] The above-mentioned refractive index guided semiconductor laser device has an M
In the case of the BE method (excluding the MOMBE (organic metal molecular beam epitaxy) method; hereinafter, simply referred to as the “MBE method”), it is manufactured as follows. First, as shown in FIG. 7A, the first conductivity type GaAs substrate 1 is formed on the GaAs substrate 1 by the MBE method.
First conductivity type GaAs buffer layer 2, first conductivity type GaInP buffer layer 3, first conductivity type AlGaInP first cladding layer 4, GaInP active layer 5, second conductivity type AlGaInP second cladding layer 6, second conductivity type GaInP The intermediate layer 9 and the second conductivity type GaAs contact layer 10 are sequentially grown (first growth). Next, as shown in FIG. 2B, a resist 17 is patterned in a stripe pattern on the GaAs contact layer 10, and as shown in FIG. The GaInP intermediate layer 9 and the AlGaInP clad layer 6 are selectively etched partway. As a result, the mesa portion 35 protruding in a stripe shape is formed on the substrate 1. Next, after the resist 17 is removed, as shown in FIG.
A first conductivity type GaAs current blocking layer 11 is grown thereon.
(2nd growth). As a result, both sides of the mesa portion 35 are Ga.
It is filled with an As current blocking layer 11. At this time, GaAs
Unnecessary crystal 30 grows on contact layer 10. Therefore, as shown in FIG. 1E, the crystal 30 on the GaAs contact layer 10 is removed by photolithography using mask alignment. Finally, as shown in FIG.
The electrodes 12 and 13 are formed on the front and back sides of the device, respectively, to complete the fabrication.

On the other hand, in the case of MOCVD or MOMBE, selective growth can be performed when growing the GaAs current blocking layer 11 shown in FIG. That is, as shown in FIG. 8A, a dielectric film 16 such as SiO ₂ is formed on the mesa portion 35, and the MO film is formed as shown in FIG.
The GaAs current blocking layer 11 is grown thereon by the CVD method or the MOMBE method. In this case, Si
Unnecessary crystals do not grow on the O ₂ film 16. After this,
As shown in (c) and (d), the SiO ₂ film 16 was removed and the electrode 1 was removed.
2, 13 are formed. According to this step, the element can be manufactured by self-alignment.

[0007]

When an index guided semiconductor laser device is manufactured by the MBE method, as described above, the unnecessary crystal 30 (FIG. 7) on the mesa portion 35 (GaAs contact layer 10) is used. (d), it is necessary to perform photolithography using mask alignment.
Here, there is a problem that performing this photolithography requires appropriate skill. Since the surface of the crystal 30 is not flat, the crystal 30 is removed by etching.
The surface shape of the GaAs contact layer 10 is not flat.
Therefore, formation of the electrode 12 is hindered. Further, at the time of mounting, the adhesion between the electrode 12 and the mounting table is deteriorated, so that there is a problem that heat dissipation is reduced and contact resistance is increased. As a result, the manufactured device had poor characteristics, a large variation in drive voltage among the devices, and a sudden deterioration of the device, resulting in poor reliability.

On the other hand, when a refractive index guided semiconductor laser device is manufactured by MOCVD or MOMBE,
Although the mesa portion 35 becomes flat, the GaAs contact layer 10
The GaAs current blocking layer 11 grows in a raised state in the vicinity of both sides. For this reason, the surface of the element is not flat, which hinders the formation of the electrode 12 as in the case of the MBE method. In addition, the adhesion between the electrode 12 and the mount base is deteriorated, so that there is a problem that heat dissipation is reduced and contact resistance is increased.

Here, in the case of the MOCVD method, there is a means for performing so-called growth three times to flatten the element surface.
That is, as shown in FIG.
The element surface can be flattened by further growing the second conductivity type GaAs second contact layer 19 on the 0 and GaAs current blocking layers 11 (third growth). However, in this case, since the second GaAs contact layer 19 is thick, heat dissipation is rather poor. Further, since the growth is performed three times, there is a problem that the operation efficiency of the growth apparatus is reduced.

Incidentally, the present applicant has recently provided an etching stop layer made of an oxide film (dielectric film) when manufacturing a refractive index guided semiconductor laser device by the MBE method, thereby flattening the device surface. Process was proposed. In this process, first, as shown in FIG.
The first conductivity type GaAs buffer layer 2, the first conductivity type GAInP buffer layer 3, the first conductivity type AlGaInP first cladding layer 4, Ga
InP active layer 5, second conductivity type AlGaInP second cladding layer 6, GaInP etching stop layer 7, second conductivity type Al
A third GaInP cladding layer 8, a second conductivity type GaInP intermediate layer 9, and a second conductivity type GaAs contact layer 10 are sequentially grown (first growth). Next, an oxide film 14 is deposited as an etching stop layer on the second conductivity type GaAs contact layer 10, and a resist 17 is patterned on the oxide film 14 in a stripe shape. Next, as shown in FIG. 2B, the oxide film 14 is selectively etched using the resist 17 as a mask. Next, as shown in FIG. 2C, after removing the resist 17, the GaAs contact layer 10, the GaInP intermediate layer 9, and the AlGaInP clad layer 8 are partially etched using the oxide film 14 as a mask. Thus, the protruding mesa portion 36 is formed on the substrate 1. Thereafter, as shown in FIG. 4D, the etching is selectively performed up to the upper part of the GaInP etching stop layer 7. Next, as shown in FIG.
A first conductivity type current blocking layer 11 is grown thereon (second
Second growth). Thus, both sides of the mesa portion 36 are filled with the first conductivity type current element layer 11. At this time, a GaAs polycrystal (unnecessary crystal) 15 grows on the oxide film 14. Next, as shown in FIG. 2F, a resist 18 is applied thereon by a spinner. At this time, a thick resist is applied on the flat first conductivity type current blocking layer 11, but a very thin resist is applied on the protruding GaAs polycrystal 15. Next, as shown in FIG.
Ashing is performed on the entire surface of the substrate for a limited time to leave the resist on the first conductivity type current blocking layer 11 while completely removing the resist on the GaAs polycrystalline layer 15. Next, FIG.
As shown in FIG. 3B, the GaAs polycrystal 15 is selectively etched down to the oxide film 14 using the remaining resist 18 as a mask. After removing the remaining resist 18, as shown in FIG. 11 (i), the oxide film 14 is removed by etching, and electrodes 12 and 13 are formed on the front side and the back side of the device. In this case, a refractive index guided semiconductor laser device having a flat surface can be manufactured. However, since the oxide film (dielectric film) 14 is provided instead of the semiconductor layer to stop the etching, a step of depositing the oxide film 14 and a step of patterning the oxide film 14 in a stripe pattern must be provided. As a result, the number of steps is increasing. For this reason, there is a problem that much work time (man-hours) is required.

Therefore, an object of the present invention is to provide a so-called double growth and self-aligned semiconductor laser device having a flat surface without providing a dielectric film for stopping etching, and therefore, it is possible to easily manufacture a semiconductor laser device. It is an object of the present invention to provide a method of manufacturing a semiconductor laser device capable of improving radiation, reducing contact resistance, and improving device characteristics and reliability.

[0012]

In order to achieve the above object, a method of manufacturing a semiconductor laser device according to the present invention comprises a first conductive type clad layer, an active layer, A two-conductivity-type cladding layer, a second-conductivity-type contact layer, an etching stop layer made of (Al _x Ga _1-x ) As, and having an Al mixed crystal ratio lower than that of the etching stop layer (Al _y Ga _{1 -x} ). _y ) a step of sequentially growing an As cap layer, and providing a resist in a stripe shape on the cap layer by performing photolithography, and using the resist as a mask, a predetermined etching solution is used to remove the second conductive type from the cap layer. A step of forming a striped mesa portion on the substrate by etching halfway through the cladding layer, and removing the resist, and then growing a first conductivity type current blocking layer on the substrate. A step of filling both sides of the mesa portion with the current blocking layer, a step of applying a resist on the substrate, and ashing the resist until a portion of the current blocking layer deposited on the mesa portion is exposed And, using the resist remaining on the substrate as a mask, a portion of the current blocking layer deposited on the mesa portion and the cap layer immediately below the current blocking layer using a predetermined etching solution, as the etching stop layer. A step of selectively etching until the above, and after removing the remaining resist, removing the etching stop layer exposed on the mesa portion using a predetermined etching solution to expose the second conductive type contact layer. The method is characterized by including a step of causing the step to be performed.

Further, according to the method of manufacturing a semiconductor laser device of the present invention, an n-type (Al _p Ga _{1 -p} ) ₀ .0 is formed on an n-type GaAs semiconductor substrate.
₅ and an In _{0. 5} P clad _{layer, (Al q Ga 1-q} ) 0. 5 In 0. 5 P active layer and, p-type _{(Al r Ga 1-r)} 0. 5 In 0. 5 P cladding layer And the p-type
_{(AlsGa 1- s) 0. 5} In 0. 5 and P intermediate layer, and a p-type GaAs first contact layer, and the _{(Al x Ga 1-x)} As etching stop _{layer, (Al y Ga 1-y} ) As A step of growing a cap layer so as to satisfy all the conditions of q <p, rr> 0.2 s <0.2 y <x; and performing photolithography to form the (Al _y Ga _1-y ) As cap layer. A resist is provided in the form of a stripe on the top, and using the resist as a mask, a predetermined etching solution is used to form the above (Aly _).
Ga _1-y) p-type from As cap layer _{(Al r Ga 1-r)} 0. 5 In 0. 5 A
a step of forming a striped mesa portion on the substrate by etching halfway through the s-cladding layer, and after removing the resist, growing a p-type GaAs second contact layer on the substrate; A step of filling both sides of the mesa portion with the second contact layer, applying a resist on the substrate, and ashing the resist until the portion of the second contact layer deposited on the mesa portion is exposed; Using the resist remaining on the substrate as a mask, a predetermined etchant to remove the portion of the second contact layer deposited on the mesa portion and the cap layer immediately below, A step of selectively etching up to the layer, and an etching exposed to the mesa portion using a predetermined etching solution after removing the remaining resist. A step of removing the contact stop layer to expose the first contact layer.

Further, it is desirable that the Al mixed crystal ratio x of the etching stop layer made of (Al _x Ga _1-x ) As be in the range of 0.4 ≦ x ≦ 1.0.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a semiconductor laser device according to the present invention will be described in detail with reference to embodiments.

FIGS. 1 to 3 show steps of a method for manufacturing a semiconductor laser device according to the first embodiment. In this manufacturing method, the refractive index guided semiconductor laser device shown in FIG. This semiconductor laser device has a first conductivity type GaAs buffer layer 2, a first conductivity type GaInP buffer layer 3, a first conductivity type AlGaInP first cladding layer 4, a GaInP active layer 5 on a first conductivity type GaAs substrate 1. Second conductivity type AlGaIn
A P-type second cladding layer 6, a GaInP etching stop layer 7, a second conductivity type AlGaInP third cladding layer 8, a second conductivity type GaInP intermediate layer 9, and a second conductivity type GaAs contact layer 10 are provided in this order. The AlGaInP third cladding layer 8, the GaInP intermediate layer 9, and the GaAs contact layer 10 form a stripe-shaped mesa (4 μm in width). Embed both sides of this striped mesa,
A first conductivity type GaAs current blocking layer 11 is provided. Further, an electrode 12 is provided on the GaAs contact layer 10 and the GaAs current blocking layer 11, while an electrode 13 is provided on the back surface of the substrate 1.

The semiconductor laser device is manufactured as follows. First, as shown in FIG.
A first conductivity type GaAs buffer layer 2 (0.5 μm thick) and a first conductivity type GaAs buffer layer 3 are formed on a conductivity type GaAs substrate 1.
(Thickness: 0.5 μm), first conductivity type AlGaInP first cladding layer 4 (thickness: 1 μm), GaInP active layer 5 (thickness: 0.66 μm)
m), the second conductivity type AlGaInP second cladding layer 6 (having a thickness of 0.3 mm).
2 μm), GaInP etching stop layer 7 (thickness 80
Å), the second conductive type AlGaInP third cladding layer 8 (having a thickness of 0.3 mm).
8 μm), the second conductive type GaInP intermediate layer 9 (0.05 μm thick).
m), the second conductivity type GaAs contact layer 10 (0.5 μm thick)
_{m), (Al 0. 5} Ga 0. 5) As the etching stop layer 31 (thickness 200 Å), is grown GaAs cap layer 32 (thickness 0.1 [mu] m) in order (first time growth). The gist of the present invention is that, instead of the oxide film 14 used in the manufacturing method (FIGS. 9 to 11) previously proposed by the present applicant, an (Al _x Ga _{1 -x} ) As etching stop layer (x = 0. 5) Use 31. By using the etching stop layer 31 made of a semiconductor,
The step of depositing the oxide film (dielectric film) 14 or forming a pattern in a stripe pattern can be omitted. The provision of the (Al _y Ga _1-y ) As cap layer (y = 0) 32 having a lower Al composition ratio than that of the etching stop layer 31 prevents the etching stop layer 31 from being oxidized. To do that. Next, a resist 17 is pattern-formed in a stripe shape having a width of 4 μm by photolithography. Subsequently, as shown in FIG. (B), the resist 17 as a mask, using a GaAs selective etchant ammonia based or based sulfate, GaAs cap layer _{32, (Al 0. 5 Ga} 0. 5) A
s etching stop layer 31, GaAs contact layer 10
Is etched all at once. Next, as shown in FIG. 3 (c), a GaInP intermediate layer 9 and an AlGaInP third etchant are sequentially used using a hydrochloric acid-based or bromine-based etchant and a sulfuric acid-based or phosphoric acid-based etchant.
The cladding layer 8 is etched until the GaInP etching stop layer 7 is exposed. Thereby, the GaInP substrate 1
The above-mentioned stripe-shaped mesas are formed thereon. After that, the resist 17 is removed. Next, as shown in FIG. 2D, the first conductivity type GaAs current blocking layer 11 (thickness: 1.35 μm) is formed thereon by MBE.
Is grown (second growth). At this time, an unnecessary crystal 30 having a projection shape grows on the GaAs cap layer 32. Next, as shown in FIG.
8 is applied by a spinner. At this time, the flat GaAs
Although a thick resist is applied on the current blocking layer 11, the resist is hardly applied on the crystal 30 projecting in a ridge stripe shape. Next, as shown in FIG. 2F, the entire surface of the resist 18 is slightly ashed (O ₃ -UV ashing or O ₂ plasma ashing) for a limited time, so that the resist is formed on the GaAs current blocking layer 11. On the other hand, the resist on the crystal 30 is completely removed. Next, as shown in FIG.
8 as a mask, the ammonia-based _{(Al 0. 5 Ga 0.} 5) As
The crystal 30 and the GaAs cap layer 32 are removed using a selective etchant. In this case, just below _{(Al 0. 5 Ga 0.} 5) A
s The etching stop layer 31 is not etched. To ensure etching selectivity, (AlxGa
_1- x) The mixed crystal ratio x of the As etching stop layer is set to 0.4 ≦ x ≦
This is because it is set to 1. Thereafter, as shown in FIG. 2H, all the remaining resist 18 is removed. Next, as shown in FIG. 3 (i), using a HF-based _{etchant, (Al 0. 5 Ga 0} . 5) As the etching stop layer 31
Is removed. Finally, the electrodes 12 on the front and back sides of the device
13 is formed to complete the fabrication.

As described above, according to this manufacturing method, a refractive index guided semiconductor laser device having a flat surface can be easily formed without growing a dielectric film for etching stop by growing twice and self-aligning. Can be manufactured. Since the surface of the semiconductor laser device is flat, a good electrode 12 can be manufactured, and the electrode 12 and the mount base can be properly brought into close contact with each other during mounting. Moreover, the third growth (thick contact layer growth) was not performed,
Since the growth is performed twice, the heat dissipation can be increased and the contact resistance can be reduced. When the device was actually fabricated, the threshold current was 40 mA, and the differential quantum efficiency was 60
%, A single transverse mode, and a good current-light output characteristic linearly increasing up to a light output of 20 mW. In addition, the fluctuation of the drive voltage between the elements was reduced, and the reliability was improved.

FIGS. 4 to 6 show steps of a method for manufacturing a semiconductor laser device according to a second embodiment of the present invention. In this manufacturing method, a refractive index guided semiconductor laser device shown in FIG. This semiconductor laser device utilizes a valence band barrier between AlGaInP and GaAs as a means for blocking current, and in order to constitute this valence band barrier,
The conductivity type of the substrate 21 is n-type. That is, this semiconductor laser device is formed on an n-type GaAs substrate 21 by n-type GaAs.
Buffer layer 22, n-type GaInP buffer layer 23, n-type Al
GaInP first cladding layer 24, GaInP active layer 5, p-type AlGaInP second cladding layer 26, GaInP etching stop layer 7, p-type AlGaInP third cladding layer 28, p
GaInP intermediate layer 29, p-type GaAs first contact layer 2
10 are provided in order. The p-type AlGaInP third cladding layer 28, the p-type GaInP intermediate layer 29, and the p-type GaAs contact layer 210 constitute a stripe-shaped mesa (4 μm in width). A p-type GaAs second contact layer 211 is provided so as to fill both sides of the stripe-shaped mesa. Further, the electrode 12 is provided on the p-type GaAs first contact layer 210 and the second GaAs contact layer 211, while the electrode 13 is provided on the back surface of the substrate 21.

In this semiconductor laser device, the first conductivity type is n-type and the second conductivity type is p-type in the steps 1 to 3 of the first embodiment.
The current blocking layer 11 is formed by replacing the p-type (corresponding to the second conductivity type) GaAs second contact layer 211. First, as shown in FIG. 4A, an n-type GaAs buffer layer 22 (0.5 μm thick) and an n-type GaInP buffer layer 23 (thickness 0.5μ
m), n-type AlGaInP first cladding layer 24 (1 μm thick),
GaInP active layer 5 (0.06 μm thickness), p-type AlGaInP second cladding layer 26 (0.2 μm thickness), GaInP etching stop layer 7 (80 ° thick), p-type AlGaInP third cladding layer 28 (thickness 0.8 [mu] m), p-type GaInP intermediate layer 29 (thickness 0.05 .mu.m), p-type GaAs first contact layer 210 (thickness: _{0.5μm), (Al 0. 5} Ga 0. 5) As the etching stop layer 3
1 (200 mm thick), GaAs cap layer 32 (0.1 μm thick)
m) are grown in order (first growth). 'Next, a resist 17 is pattern-formed in a stripe shape having a width of 4 μm by photolithography. continue,
As shown in FIG. (B), the resist 17 as a mask, using a GaAs selective etchant ammonia based or based sulfate, GaAs cap layer _{32, (Al 0. 5 Ga} 0. 5) A
s etching stop layer 31, GaAs contact layer 21
Etch 0 at a time. Next, as shown in FIG. 3C, the hydrochloric acid-based or bromine-based etchant and the sulfuric acid-based or phosphoric acid-based etchant are used in this order to form the GaInP intermediate layer 29 and the AlGaInP
The third cladding layer 28 is formed of the GaInP etching stop layer 7
Etch until is exposed. As a result, GaInP
The above-mentioned stripe-shaped mesas are formed on the substrate 21. After that, the resist 17 is removed. (D) Then, as shown in FIG. 3D, the p-type GaAs second contact layer 211 (thickness: 1.35
μm) (second growth). At this time, an unnecessary crystal 33 having a projection shape grows on the GaAs cap layer 32. 'Next, as shown in FIG. 5E, a resist 18 is applied thereon by a spinner. At this time, the flat Ga
Although a thick resist is applied on the As second contact layer 211, the crystal 33 protruding in a ridge stripe shape is formed.
Almost no resist is applied on top. Next, as shown in FIG. 3F, the entire surface of the resist 18 is slightly ashed for a limited time to leave the resist on the GaAs second contact layer 211, while the crystal 3
3 completely remove the resist. 'Next, as shown in FIG. (G), the remaining resist 18 as a mask, the ammonia-based _{(Al 0. 5 Ga 0.} 5) A
The crystal 33 and the GaAs cap layer 32 are removed by using a selective etchant. In this case, just below _{(Al 0. 5 Ga 0.} 5)
The As etching stop layer 31 is not etched. To ensure etching selectivity, (Al _x
Ga _1-x ) The mixed crystal ratio x of the As etching stop layer is 0.4 ≦≦
This is because x ≦ 1. Thereafter, as shown in FIG. 2H, all the remaining resist 18 is removed. 'Next, as shown in FIG. 6 (i), using a HF-based _{etchant, (Al 0. 5 Ga 0} . 5) As the etching stop layer 3
Remove one. Finally, the electrodes 1 on the front and back sides of the device
The fabrication is completed by forming 2,13.

As described above, according to this manufacturing method, the first
As in the embodiment, a refractive index guided semiconductor laser device having a flat surface can be easily manufactured by growing twice and self-aligning without providing a dielectric film for stopping etching. Since the surface of the semiconductor laser device is flat, a good electrode 12 can be manufactured, and the electrode 12 and the mount base can be properly brought into close contact with each other during mounting. Moreover, since the third growth (thick contact layer growth) is not performed, the growth is limited to the second growth.
Heat dissipation can be increased and contact resistance can be reduced. Actually, the semiconductor laser device manufactured in the second embodiment exhibits a threshold current of 45 mA, a differential quantum efficiency of 50% per one side, a single transverse mode, and a good current which linearly increases up to an optical output of 10 mW. Light output characteristics were shown. Further, as in the case of the semiconductor laser device manufactured in the first embodiment, the fluctuation of the driving voltage between the devices was reduced, and the reliability was improved. Since the GaInP etching stop layer 7 is as thin as 80 °, it does not affect the valence band barrier of AlGaInP and GaAs.

In the first and second embodiments,
Although the clad layer of the semiconductor laser device is made of AlGaInP and the active layer is made of GaInP, a double heterostructure is manufactured, but an AlGaInP-based semiconductor having another composition may be used. For example, the cladding layer may be made of an AlInP ternary mixed crystal. Further, the active layer may be made of AlGaInP quaternary mixed crystal. Further, a layer having a quantum well structure or a superlattice structure may be used as the active layer, and a guide layer is provided between the clad layer and the active layer to form an SCH (separate confinement heterostructure) structure. Is also good.

[0023]

As is clear from the above, according to the method of manufacturing a semiconductor laser device of the present invention, a flat surface can be formed without growing a dielectric film for etching stop by growing twice and self-aligning. It is possible to easily manufacture a semiconductor laser device having a refractive index waveguide. Since this semiconductor laser device has a flat surface,
Thus, the electrode 12 and the mounting table can be properly brought into close contact with each other at the time of mounting. And the third growth
Since (growth of a thick contact layer) is not performed and growth is performed twice, heat dissipation can be increased and contact resistance can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing the semiconductor laser device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a method for manufacturing the semiconductor laser device according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a method for manufacturing a semiconductor laser device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a method for manufacturing a semiconductor laser device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a method for manufacturing a semiconductor laser device according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a method for manufacturing a semiconductor laser device by a conventional MBE method.

FIG. 8 is a diagram illustrating a method for manufacturing a semiconductor laser device by a conventional MOCVD method.

FIG. 9 is a diagram illustrating a method of manufacturing a semiconductor laser device previously proposed by the present applicant.

FIG. 10 is a diagram illustrating a method of manufacturing a semiconductor laser device previously proposed by the present applicant.

FIG. 11 is a diagram illustrating a method of manufacturing a semiconductor laser device previously proposed by the present applicant.

FIG. 12 is a diagram illustrating a method for manufacturing a semiconductor laser device by a conventional MOCVD method (growth three times).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 First conductivity type GaAs substrate 2 First conductivity type GaAs buffer layer 3 First conductivity type GaInP buffer layer 4 First conductivity type AlGaInP first cladding layer 5 GaInP active layer 6 Second conductivity type AlGaInP second cladding layer 7 GaInP etching Stop layer 8 Second conductivity type AlGaInP third cladding layer 9 Second conductivity type GaInP intermediate layer 10 Second conductivity type GaAs contact layer 11 First conductivity type GaAs current blocking layer 12, 13 Electrode 14 Oxide film 15 GaAs polycrystal 16 Dielectric Body film 17, 18 Resist film 19 Second conductivity type GaAs second contact layer 21 n-type GaAs substrate 22 n-type GaAs buffer layer 23 n-type GaInP buffer layer 24 n-type AlGaInP first cladding layer 26 p-type AlGaInP second cladding layer 28 p-type AlGaInP third cladding layer 29 p-type GaInP intermediate layer 30, 33 GaAs crystal _{31 (Al 0. 5 Ga 0} . 5) As etching stop layer 32 GaAs cap layer 35, 36, 40, 240 Mesa section 210 p-type GaAs first contact layer 211 p-type GaAs second contact layer

Continued on the front page (72) Inventor Yasuo Suga 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Kentaro Tani 22-22 Nagaikecho, Abeno-ku, Osaka-shi Osaka Prefecture Inside Sharp Corporation (56 References JP-A-4-303987 (JP, A) JP-A-4-147687 (JP, A) JP-A-2-156588 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB (Name) H01S 3/18

Claims (3)

(57) [Claims] 1. A first conductive type clad layer, an active layer, a second conductive type clad layer, a second conductive type contact layer, and (Al _x Ga _1-x ) on a first conductive type semiconductor substrate. Sequentially growing an etching stop layer made of As and an (Al _y Ga _1-y ) As cap layer having an Al mixed crystal ratio lower than that of the etching stop layer; and performing stripes on the cap layer by performing photolithography. Forming a stripe-shaped mesa portion on the substrate by etching the cap layer from the cap layer to the middle of the second conductivity type cladding layer using a predetermined etching solution with the resist as a mask. Removing the resist, growing a first conductivity type current blocking layer on the substrate, filling both sides of the mesa portion with the current blocking layer, and coating the substrate with a resist. Ashing the resist until the portion of the current blocking layer deposited on the mesa is exposed, and using a predetermined etchant with the resist remaining on the substrate as a mask. A step of selectively etching the portion of the current blocking layer deposited on the mesa portion and the cap layer immediately below until the etching stop layer is reached, after removing the remaining resist, A step of removing the etching stop layer exposed in the mesa portion by using the etching solution to expose the second conductivity type contact layer. 2. An n-type (Al _p GaAs) substrate is formed on an n-type GaAs semiconductor substrate.
_{1-p) 0. 5 In} 0. 5 and P clad _{layer, (Al q Ga 1-q} ) 0. 5 In 0. 5
And P active layer, p-type _{(Al r Ga 1-r)} 0. 5 In 0. 5 and P cladding layer, p-type _{(AlsGa 1- s) 0. 5} In 0. 5 P and the intermediate layer, p-type GaAs
A first contact layer, and the _{(Al x Ga 1-x)} As etching stop layer, the _{(Al y Ga 1-y)} As cap layer, q <p, rr> 0.2 s <0.2 y <x and growing to meet all the requirements made by performing a photolithography resist provided on the (Al _y Ga _1-y) a stripe shape as cap layer, using the resist as a mask, using a predetermined etchant Above
_{(Al y Ga 1-y)} p -type from As cap layer _{(Al r Ga 1-r)} 0. 5 In
_0.5 by etching halfway As cladding layer, forming a stripe-shaped mesa portion on the substrate, after removing the resist, to grow a p-type GaAs second contact layer on the substrate Filling the two sides of the mesa with the second contact layer, applying a resist on the substrate, and exposing portions of the second contact layer deposited on the mesa in the second contact layer. Ashing step, and using a resist remaining on the substrate as a mask, a portion of the second contact layer deposited on the mesa portion and a cap layer immediately below, using a predetermined etching solution, A step of selectively etching up to the etching stop layer, and after removing the remaining resist, is exposed to the mesa portion using a predetermined etching solution. And the etching stop layer is removed, a method of manufacturing a semiconductor laser device comprising the step of exposing the first contact layer. 3. The etching stop layer comprising (Al _x Ga _1-x ) As, wherein an Al composition ratio x of the etching stop layer is in a range of 0.4 ≦ x ≦ 1.0. A method for manufacturing a semiconductor laser device according to claim 2.