JP2000269602A - Semiconductor laser and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the semiconductor laser whose operation voltage is small, whose lateral mode is stable and which has high output. SOLUTION: A boundary face on an optical waveguide between a first conductivity-type current block layer 16 and a second conductivity-type embedded layer 17 are installed on a (111)B face facet of an optical waveguide side. Thus, a role of widening an effective current path without widening the width of an active layer 13 is displayed, and a rate that the bearing of the crystal growing face of the second conductivity-type buried layer 17 directly above the optical waveguide applied to the effective current path is a (100) face whose doping efficiency is satisfactory becomes more frequent in the growing process of the second conductivity-type embedded layer 17. Thus, effect that element resistance can be reduced can also be obtained since the doping efficiency of the second conductivity-type embedded layer 17 applied to the effective current path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor laser device, and more particularly to a long-wavelength high-power semiconductor laser device and a method of manufacturing the same, and more particularly to a low-resistance, high-output semiconductor laser device and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, an EDFA (Erbium Do) is used.
High power laser device for ped fiber amplifier (OTDR), Optical Time Do
2. Description of the Related Art In a long-wavelength high-power semiconductor laser such as a high-power laser device for a main reflector, it is desirable to reduce the element resistance in order to suppress heat generation when a large current is injected. For this reason, for example, a method of increasing the carrier concentration of the buried layer of the second conductivity type to reduce the element resistance has been adopted.

FIGS. 11 to 17 are views showing a method for manufacturing a conventional semiconductor laser device. 11 to 17 are shown in the order of steps.

First, (10) of the n-type InP substrate 11
On the 0) surface, a thermal chemical vapor deposition method (thermal CVD: Chemica
A SiO ₂ film having a thickness of 100 nm is deposited by 1 Vapor Phase Epitaxy, and a pair of 5.0 μm-wide SiO ₂ patterning masks 30 ′ having an opening region having a width of 2.4 μm in the <011> direction are formed by photolithography. Form.

[0005] Next, as shown in FIG. 11, SiO ₂ film 3
Metalorganic vapor phase epitaxy (MOVPE: Me)
tal-Organic Vapor Phase E
an n-type InP cladding layer 12 having a layer thickness of 0.1 μm and a carrier concentration of 1.0 × 10 ¹⁸ cm ⁻³ by a pitxy) method;
An active layer 13 composed of multiple quantum wells and a layer thickness of 0.15 μm
An optical waveguide layer 50 'composed of m and a p-type InP cladding layer 14 having a carrier concentration of 5.0 × 10 ¹⁷ cm ⁻³ is grown. The multiple quantum well active layer 13 has a wavelength composition of 1.13 μm.
m, carrier concentration 1.0 × 10 ¹⁸ cm ⁻³ , layer thickness 30 nm
N-type InGaAsP guide layer having a wavelength composition of 1.20 μm
m, an InGaAsP barrier layer having a layer thickness of 7.0 nm, and an I layer having a wavelength composition of 1.45 μm, a layer thickness of 4.0 nm, and a strain amount of 1.0%.
An nGaAsP strained quantum well layer having a wavelength composition of 1.13 μm,
It is composed of a p-type InGaAsP guide layer having a thickness of 30 nm, and the number of strain quantum well layers is three.

[0006] Next, as shown in FIG.
An m ₂ SiO ₂ film is deposited on the entire surface by thermal CVD. At this time, the SiO ₂ film on the side surface of the optical waveguide is thinner than the SiO ₂ film on the n-type InP substrate 11 and the top of the optical waveguide due to the difference in the plane orientation on which the deposit is attached.

Next, as shown in FIG. 13, the entire surface is etched with buffered hydrofluoric acid for about 6 minutes. In the SiO ₂ film 30 ′, only the SiO ₂ film on the side surface of the optical waveguide disappears due to the difference in film thickness between the flat portion and the side surface of the optical waveguide, and the semiconductor layer is exposed on the side surface of the optical waveguide. At this time, since the etching time is set so as to completely remove the SiO ₂ film on the side surface,
The SiO ₂ film immediately above the optical waveguide is also partially etched.

Next, as shown in FIG. 14, a photoresist 40 is applied by photolithography so as to cover the entire surface of the optical waveguide. At this time, the photoresist 40
Is SiO ₂ on the n-type InP substrate and on top of the optical waveguide.
The film 30 'is in close contact with the semiconductor layer on the side surface of the optical waveguide.

Next, as shown in FIG. 15, etching is performed for 9 minutes using buffered hydrofluoric acid. The SiO ₂ film 30 ′ in the flat region on the n-type InP substrate is removed by side etching.

[0010] Thereafter, as shown in FIG.
The SiO ₂ film 30 ′ is formed on the top of the optical waveguide by stripping
Is obtained.

[0011] Next, as shown in FIG. 17, SiO ₂ film 3
The p-type InP current blocking layer 15 having a layer thickness of 0.6 μm and a carrier concentration of 6.0 × 10 ¹⁷ cm ^-3 and a layer thickness of 0.6 μm and a carrier concentration of 3.0 × 10 ^{18 are} obtained by MOVPE using 0 ′ as a selective growth mask. An n-type InP current blocking layer 16 of cm ^-3 is selectively grown.

[0012] Next, as shown in FIG. 18, SiO ₂ film 3
After removing 0 ′ with buffered hydrofluoric acid, the doping concentration was set to 1.0 × 10 ¹⁸ cm to reduce the device resistance.
A p-type InP buried layer 17 having a layer thickness of 3.0 μm and a high concentration of ⁻³ μm;
¹⁸ cm ^-3 p-type InGaAs contact layer and MOVP
The entire surface is grown by the E method. After that, a p-side electrode 19 and an n-side electrode 20 are formed.

According to the above manufacturing method, a current confinement structure having a pnpn thyristor structure is formed, and a semiconductor laser device capable of effectively injecting a current into an active layer is obtained.

[0014]

In a semiconductor laser device as shown in the above-mentioned conventional example, even if the doping amount of impurities is increased in order to increase the carrier concentration of the p-type InP buried layer, the effective carrier concentration remains unchanged. There is a problem that the element resistance cannot be sufficiently reduced without increasing.

That is, in the case of a selective buried growth type semiconductor laser device utilizing an edge glow region as shown in the conventional example, the n-type InP block layer 16 has a shape in which the (111) B surface protrudes above the optical waveguide. Therefore, n
There has been a problem that the interval between the type InP block layers, that is, the width of the effective current path may be reduced (FIG. 18).

In the p-type InP buried layer 17,
A p-type InP buried layer 17 immediately above the active layer corresponding to the effective current path grows on the (111) B plane, and the (111) B
Since the surface is less likely to form dangling bonds during crystal growth and has lower doping efficiency than the (100) plane, the p-type InP buried layer 17 in the region immediately above the optical waveguide corresponding to the effective current path is made of, for example, n-type InP. There is a problem that the carrier concentration may be relatively lower than that of the p-type InP buried layer 17 on the block layer 16.

Due to the above two problems, regarding the reduction of the resistance of the effective current path for suppressing heat generation at the time of injecting a large current,
Not enough.

As a method of solving the above problem, for example, a method of widening the width of the optical waveguide to increase the width of the top of the optical waveguide can be considered. There is a concern that the coupling efficiency to the fiber is greatly deteriorated due to the disturbance.

An object of the present invention is to provide a semiconductor laser device in which the effective current path is widened in order to solve the above problem.

Another object of the present invention is to increase the effective carrier concentration of the p-type InP buried layer corresponding to the effective current path, thereby suppressing heat generation even when a large current is injected with low resistance. Another object of the present invention is to hand-mirror a high-power semiconductor laser device whose lateral mode is controlled.

Still another object of the present invention is to provide a long-wavelength band high-power semiconductor laser device having a small absorption loss.

[0022]

In order to achieve the above object, a semiconductor laser device according to the present invention comprises a metalorganic vapor phase using a dielectric mask having a striped window formed on a semiconductor substrate of a first conductivity type. An optical waveguide formed by sequentially stacking a first conductivity type cladding layer, an active layer having a multiple quantum well structure, and a second conductivity type cladding layer selectively formed by a growth method; (11) on the side of the optical waveguide
1) a second conductivity type current block layer made of at least a second conductivity type semiconductor and selectively grown by a metal organic chemical vapor deposition method in a region excluding a partial region of the B surface; A first conductivity type current blocking layer made of the first conductivity type semiconductor formed on the entire surface of the optical waveguide and the first conductivity type current blocking layer, at least a second conductivity type buried layer made of the second conductivity type semiconductor, It is characterized by having.

Also, it is assumed that the boundary surface of the first conductivity type current blocking layer and the second conductivity type buried layer on the optical waveguide is on the (111) B surface of the second conductivity type cladding layer on the side surface of the optical waveguide. Features.

It is preferable to use a strained quantum well in the multiple quantum well structure.

In the method of manufacturing a semiconductor laser device according to the present invention, the step of selectively growing the current block layer includes the steps of forming an optical waveguide including an active layer by metalorganic vapor phase epitaxy, and forming a SiO 2 layer over the entire surface by thermal CVD. _{By using} the step of depositing the _two films and the thickness difference of the SiO ₂ film between the top and the side of the optical waveguide, the (100) plane at the top of the optical waveguide and the (111) on the side of the optical waveguide are used. A) forming a SiO ₂ film only in a part of the B-plane, forming a current blocking layer using the SiO ₂ film as a growth inhibiting film,
Forming a buried layer on the entire surface after removing the _two films.

As described above, in the long-wavelength band high-power semiconductor laser device according to the present invention, in particular, the boundary surface of the first conductive type current blocking layer and the second conductive type buried layer on the optical waveguide is located on the side of the optical waveguide. (111) B of the second conductivity type cladding layer
It has a structure on a surface.

As described above, since the boundary between the first conductivity type current blocking layer and the second conductivity type buried layer is on the side face of the optical waveguide, the distance between the first conductivity type current blocking layers, that is, the effective current path width is reduced. Plays the role of being able to be wider. Furthermore, in the process of growing the buried layer of the second conductivity type, the crystal growth plane orientation of the buried layer of the second conductivity type immediately above the optical waveguide corresponding to the effective current path has poor doping efficiency (11).
1) The area of the (100) plane having higher doping efficiency than the B plane is increased. Thereby, the effect that the element resistance can be reduced as compared with the conventional example is synergistically obtained. As a result of reducing the element resistance, heat generation at the time of injecting a large current can be suppressed, and deterioration of optical output can be suppressed.
Therefore, the semiconductor laser device of the present invention has an effect that low resistance and high output can be obtained.

[0028]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a semiconductor laser device according to an embodiment of the present invention.

In order to clarify the above and other objects, features and advantages of the present invention, an embodiment of a semiconductor laser device of the present invention will be described below in detail with reference to the drawings.

The embodiment of the semiconductor laser device of the present invention is the same as that of the first conductive type clad layer 1 on the first conductive type substrate 11.
2, an optical waveguide composed of the InGaAsP active layer 13 and the second conductivity type cladding layer 14 is selectively formed, and the second conductivity type current blocking layer 15, the first conductivity type current blocking layer 16,
The second conductive type buried layer 17 is formed, and the boundary surface between the first conductive type current blocking layer 16 and the second conductive type buried layer 17 is formed on the side face of the second conductive type clad layer 14 on the facet on the side face of the optical waveguide layer. It has a certain configuration.

According to this structure, the distance between the first conductivity type current blocking layers 16, ie, the effective current path, can be widened, and the second conductivity type buried layer 17 immediately above the optical waveguide corresponding to the effective current path. The region where the crystal growth plane orientation of (1) is a (100) plane having good doping efficiency increases, and the second conductivity type buried layer 17 corresponding to the effective current path is formed.
Doping efficiency increases, and the device resistance can be reduced. Therefore, heat generation at the time of injection of a large current can be suppressed, and a high-output semiconductor laser device with small light output saturation can be obtained.

[0033]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

Next, a first embodiment of the method for manufacturing a semiconductor laser device according to the present invention will be described in detail with reference to FIGS.

FIGS. 2 to 8 are sectional views showing the steps of a first embodiment of the method for manufacturing a semiconductor laser device according to the present invention. This drawing is a cross-sectional view taken along the line AA in FIG. 1 and is shown in FIGS.

First, referring to FIG. 2, first, an n-type I
A layer thickness of 10 is formed on the (100) plane of the nP substrate 11 by thermal CVD.
A pair of 5.0 μm-wide SiO ₂ patterning masks 3 is formed by depositing a 0 nm SiO ₂ film and providing an opening region having a width of 2.4 μm in the <011> direction by photolithography.
0 is formed. Next, MO is applied to the opening region of the SiO ₂ film 30.
Layer thickness 0.15μ by VPE (metal organic chemical vapor deposition) method
m, an n-type InP cladding layer 12 having a carrier concentration of 1.0 × 10 ¹⁸ cm ⁻³ , an active layer 13 composed of multiple quantum wells,
An optical waveguide 50 composed of a p-type InP cladding layer 14 having a layer thickness of 1.0 μm and a carrier concentration of 5.0 × 10 ¹⁷ cm ^−3.
Grow. The multiple quantum well active layer 13 has a wavelength composition of 1.
13 μm, carrier concentration 1.0 × 10 ¹⁸ cm ⁻³ , layer thickness 3
0 nm n-type InGaAsP guide layer and wavelength composition 1.
An InGaAsP barrier layer having a thickness of 20 μm and a thickness of 7.0 nm, a wavelength composition of 1.45 μm, a thickness of 4.0 nm, and a strain amount of 1.
0% InGaAsP strained quantum well layer and a wavelength composition 1.1
It is made of a p-type InGaAsP guide layer having a thickness of 3 μm and a thickness of 30 nm, and the number of strain quantum well layers is three.

Next, with reference to FIGS. 3 to 7, a description will be given of a process of forming a growth blocking film for a current blocking layer, which is a feature of the present invention.

As shown in FIG. 3, a 450 nm thick Si
O_TwoThe films 30a, 30b, 30c are formed on the entire surface by thermal CVD.
Deposit. At this time, the orientation of the
Therefore, the SiO on the side surface of the optical waveguide 50_TwoThe membrane 30c is
SiO on n-type InP substrate 11 _TwoFilm 30b and optical waveguide
SiO on top of road 50_TwoIt is thinner than the film 30a.

Next, as shown in FIG. 4, the entire surface is etched with buffered hydrofluoric acid for 5 minutes and 30 seconds. This etching is, unlike the conventional example, since the shorter etching time, if the SiO ₂ film thickness, the film thickness difference between the SiO ₂ film 30c of SiO ₂ film 30b and the waveguide side of the flat portion, the light The SiO ₂ film disappears only in a part of the side surface of the waveguide, that is, in a part of the optical waveguide slope (region a in FIG. 4), and the p-type InP clad layer 14 is exposed.

Next, as shown in FIG. 5, using a stepper exposure apparatus, a photoresist 4 is applied to cover the entire surface of the optical waveguide.
Cover with 0. At this time, the photoresist 40 and the p-type I
The nP cladding layer 14 is in close contact with the region a on the (111) B plane.

Next, as shown in FIG. 6, etching is performed for 7 minutes using buffered hydrofluoric acid, and the SiO ₂ film 30b in the flat region on the n-type InP substrate and the region below point a on the side surface of the optical waveguide are etched. a SiO ₂ film is removed by a side etching. The SiO ₂ film 30d above the region a is a
Since the photoresist and the p-type InP cladding layer 14 are in close contact with each other in the region, buffered hydrofluoric acid does not enter and remains.

Thereafter, as shown in FIG.
Then, a structure in which the SiO ₂ film 30d is formed on the top of the optical waveguide and a part of the side surface of the optical waveguide is obtained.

Next, as shown in FIG. 8, SiO ₂ film 30
Using the d as a selective growth mask, a p-type InP current blocking layer 15 having a layer thickness of 0.6 μm and a carrier concentration of 6.0 × 10 ¹⁷ cm ⁻³ and a layer thickness of 0.6 μm and a carrier concentration of 3.0 × 10 ^{18 were} obtained by MOVPE. An n-type InP current blocking layer 16 of cm ^-3 is selectively grown.

FIG. 9 is a sectional view showing a semiconductor laser device manufactured according to the first embodiment of the method for manufacturing a semiconductor laser device of the present invention.

As shown in FIG. 9, in this embodiment, SiO 2
After ₂ film 30d is removed by buffered hydrofluoric acid, p layer thickness 3.0 [mu] m, carrier concentration 7.0 × 10 ¹⁷ cm ^-3
The entire InP buried layer 17 is grown by MOVPE. At this time, the growth plane orientation of the p-type InP buried layer 17 immediately above the optical waveguide corresponding to the effective current path is n-type I-type.
Since the distance between the nP current blocking layers 16 is wide, the ratio of the (100) plane having good doping efficiency increases. Thereby, the effective carrier concentration of the p-type InP buried layer 17 corresponding to the effective current path can be increased.
By increasing the effective carrier concentration, the effective current path can be reduced in resistance, and even when a large current is injected, light output saturation due to heat generation of the element can be suppressed, and high output can be obtained.

The semiconductor laser device manufactured as described above is cut into a cavity length of 1200 μm, and 4
% Low-reflection coating and 95% high-reflection coating on the rear end face, and junction-down fusion to AlN heat sink. After measuring the laser characteristics, the device resistance at the time of 500 mA injection was 1.8 V. 0.3V can be reduced compared with the example, and the maximum light output is 300
mW, which is about 20 mW higher than the conventional example.

In the above-described embodiment, the present invention is applied to a long-wavelength band high-power semiconductor laser device. However, lowering the resistance is a very important factor in all semiconductor laser devices. In addition, the present invention can be applied to general semiconductor lasers for forming an optical waveguide layer, a current blocking layer, and a buried layer by selective growth. Also,
Although the through-width of the selective growth mask has been described as being 2.4 μm, it goes without saying that the active layer structure can be made wider by preventing the formation of higher-order modes.

Next, a second embodiment of the present invention will be described.

FIG. 10 is a sectional view showing a second embodiment of the semiconductor laser device of the present invention. The feature of this embodiment is that the carrier concentration of the p-type InP cladding layer 14 is reduced. Here, the OTD of 1.55 μm band
The high-power laser for R (optical fiber fault point detector) will be described in detail.

First, (10) of the n-type InP substrate 11
On the 0) plane, a 100-nm thick SiO_TwoMembrane
Deposited in the <011> direction by photolithography
And a pair of 5.0 μm in width provided with an opening area of 2.4 μm in width
SiO_TwoA patterning mask 30 is formed. next,
SiO_TwoA layer thickness of 0.3 is applied to the opening region of the film by the MOVPE method.
μm, carrier concentration 1.0 × 10¹⁸cm^-3N-type InP
Cladding layer 12 and active layer 13 composed of multiple quantum wells
And a layer thickness of 0.5 μm and a carrier concentration of 2.0 × 10 ¹⁷cm
^-3Optical waveguide composed of p-type InP cladding layer 14
Grow 50. The multiple quantum well active layer 13 has a wavelength composition
1.13 μm, carrier concentration 1.0 × 10 ¹⁸cm^-3,layer
30 nm thick n-type InGaAsP guide layer and wavelength composition
1.20 μm, 7.0 nm thick InGaAsP barrier
Layer, wavelength composition 1.50 μm, layer thickness 4.0 nm, strain amount
1.0% InGaAsP strained quantum well layer and wavelength composition
1.13 μm p-type InGaAsP guide with 30 nm thickness
And the number of strained quantum well layers is three. Next
Next, the optical waveguide 50 is directly connected to the optical waveguide 50 in the same manner as in the first embodiment.
The upper portion and a part of the side surface of the optical waveguide 50 are made of SiO._TwoShape the membrane
And a p-type InP current blocking layer 1 formed by MOVPE.
5 (layer thickness 1.5 μm, carrier concentration 6.0 × 10¹⁷cm
^-3) And n-type InP current blocking layer 16 (layer thickness 1.5
μm, carrier concentration 3.0 × 10¹⁸cm^-3Select growth)
I do. Next, the SiO_TwoRemove membrane with buffered hydrofluoric acid
After removal, the p-type InP buried layer 17 (layer thickness 3.0 μm)
m, carrier concentration 7.0 × 10¹⁷cm^-3) To MOVPE
The entire surface is grown by the method. At this time, it corresponds to the effective current path.
Of the p-type InP buried layer 17 immediately above the optical waveguide
Plane orientation is SiO_Two(111) B surface due to wide width of film
, The ratio of the (100) plane is larger. Growth surface
When the azimuth is the (100) plane, compared to the (111) B plane
High doping efficiency
Wear. This reduces the resistance of the effective current path,
Even when an input current flows, heat generation can be suppressed. Next
The p-type InGaAs contact layer 18 (having a thickness of 0.3 μm)
m, carrier concentration 5.0 × 10¹⁸cm^-3) To MOVPE
The entire surface is grown by the method. Finally, the p-side electrode 19 and the n-side electrode
Semiconductor laser device having pole 20 formed therein and having the structure of the present invention
The installation is completed.

Here, when the oscillation wavelength is in the long wavelength band such as the 1.55 μm band, compared with the short wavelength band such as the 1.3 μm band, the absorption between the valence bands in the p-type InP layer (IVBA:
Interval Band Absorbt
ion) becomes stronger. For this reason, if the carrier concentration is high, the absorption loss increases, the device characteristics deteriorate, and high output characteristics cannot be obtained. Literature (The Effect o
f Interval Band Absor
ption on the ThermalBehav
ior of InGaAsP Lasers, IE
EE J Quantum Electronic
s. , Vol. QE-19, pp947-952,
According to 1983), the IVBA in the 1.55 μm band is p
When the carrier concentration of the type InP layer is 1.0 × 10 ¹⁸ cm ⁻³ , the value is as large as about 25 cm ⁻¹ .

According to the present embodiment, since the carrier concentration of the p-type InP cladding layer 14 near the active layer where the seeping of the light field is large is as low as 3.0 × 10 ¹⁷ cm ⁻³ , the absorption loss is reduced. Semiconductor laser device with a small size is obtained. In the case of this embodiment, about 3.0 cm ^-1 is compared with the conventional example.
Absorption loss was reduced.

The produced semiconductor laser device was cut to a cavity length of 900 μm, a low-reflection film coating of 6% was applied to the emission end face, and a high-reflection film coating of 95% was applied to the rear end face. After the attachment, the laser characteristics were measured. As a result, the internal loss was extremely small at 5.0 cm ^-1, and excellent characteristics were obtained. The optical output at an injection current of 1 A was 380 mW.

It should be noted that the present invention is not limited to the above embodiments, and it is clear that the embodiments can be appropriately modified within the scope of the technical idea of the present invention.

[0055]

As described above, according to the present invention, the effective current path can be widened and the carrier concentration of the p-type InP buried layer corresponding to the effective current path can be increased. It is possible to reduce heat generation during large current injection. Therefore, there is an effect that a high output can be realized in a long wavelength band high output semiconductor laser device.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an embodiment of the present invention.

FIG. 2 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 3 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 4 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 5 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 6 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 7 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 8 is a sectional view showing a first embodiment of a method for manufacturing a semiconductor laser device of the present invention.

FIG. 9 is a sectional view showing a configuration of a first example of the semiconductor laser device of the present invention.

FIG. 10 is a sectional view showing the configuration of a second embodiment of the semiconductor laser device of the present invention.

FIG. 11 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 12 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 13 is a sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 14 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 15 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 16 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 17 is a sectional view illustrating a method for manufacturing a conventional semiconductor laser device.

FIG. 18 is a cross-sectional view illustrating a configuration of a conventional semiconductor laser device.

[Explanation of symbols]

Reference Signs List 11 n-type InP substrate 12 n-type InP cladding layer 13 InGaAsP active layer 14 p-type InP cladding layer 15 p-type InP current blocking layer 16 n-type InP current blocking layer 17 p-type InP burying layer 18 p-InGaAs cap layer 19 p side top portion and side surface of the electrode 20 n-side electrode 30 SiO ₂ growth inhibiting film 30 'SiO ₂ film (conventional example) 30a SiO ₂ film top portion 30b SiO ₂ film of the flat portion 30c SiO ₂ film side portion 30d SiO ₂ film of the Part of part 40 Photoresist 50 Optical waveguide 50 'Optical waveguide (conventional example)

Claims (6)

[Claims] 1. A first conductivity type cladding layer and a multiple quantum well selectively formed by a metal organic chemical vapor deposition method on a first conductivity type semiconductor substrate using a dielectric mask having windows opened in stripes. An optical waveguide in which an active layer having a structure and a second conductivity type cladding layer are sequentially laminated; and a region excluding a partial region of a (100) plane on the top of the optical waveguide and a (111) B plane on a side surface of the optical waveguide. A second conductivity type current block layer made of at least a second conductivity type semiconductor, selectively grown by metal organic chemical vapor deposition, and a first conductivity type semiconductor formed on the second conductivity type current block layer A first conductivity type current block layer; and a second conductivity type buried layer made of at least a second conductivity type semiconductor on the entire upper surface of the optical waveguide and the first conductivity type current block layer. Semiconductor laser The equipment. 2. A boundary between the current block layer of the first conductivity type and the buried layer of the second conductivity type on the optical waveguide is (1) of the second conductivity type clad layer on the side surface of the optical waveguide.
11) The semiconductor laser device according to claim 1, wherein the semiconductor laser device is located on a surface B. 3. The semiconductor laser device according to claim 1, wherein said first conductivity type semiconductor is n-type, and said second conductivity type semiconductor is p-type. 4. The semiconductor laser device according to claim 1, wherein a strained quantum well is used for said multiple quantum well structure. 5. The semiconductor laser device according to claim 1, wherein said semiconductor laser device is applied to a semiconductor laser device having a long wavelength band and high output. 6. The step of selectively growing a current blocking layer includes: a step of forming an optical waveguide including an active layer by a metal organic chemical vapor deposition method; a step of depositing an SiO ₂ film over the entire surface by thermal CVD; Utilizing the difference in the thickness of the SiO ₂ film between the top and the side of the waveguide, the (100)
Forming a SiO ₂ film on the surface and only in a part of the (111) B plane on the side surface of the optical waveguide; forming a current blocking layer using the SiO ₂ film as a growth inhibiting film; Forming a buried layer on the entire surface after removing the _two films, and a method of manufacturing a semiconductor laser device.