JPH0677607A - Semiconductor laser element and fabrication thereof - Google Patents

Abstract

PURPOSE:To permit efficient capturing of oscillation light by providing a current block layer closely to an optical guide layer in a window region, making the current block layer transparent for the oscillation light, thereby minimizing leakage current entering into the window region. CONSTITUTION:Oscillation light from a quantum well active layer 3 is guided in a p-buried guide layer 5 provided closely to a resonator surface 40 in a window region and then emitted from the right and left resonators 40. Since the p-buried guide layer 5 is transparent for the oscillation light and the oscillation light is not absorbed by the resonator surface 40, thermal fracture does not take place and stabilized operation is ensured upto high output. Furthermore, an n-current block layer 7 having different conductivity type is provided closely on the optical guide layer 5 in the window region in order to suppress leakage current entering into the window region effectively. The n-current block layer 7 does not absorb the oscillation light and thereby does not deteriorate the oscillation characteristics of laser element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-power semiconductor laser device required as a light source for an optical information processing system or a future inter-satellite optical communication system and a manufacturing method with high productivity.

[0002]

2. Description of the Related Art 50 in an oscillation wavelength band of 0.7 to 1.0 μm
A semiconductor laser device which has a high output of mW or more and stably operates in a single transverse mode has been desired in various fields. For example, in the field of optical information processing, a semiconductor laser device that stably operates with a single fundamental transverse mode output of 50 mW or more is required as a light source of an optical disk device. Further, as a light source for inter-satellite optical communication, there is a need in the future for a laser element that operates at a stable fundamental transverse mode output with a high output of 100 mW or more in the same wavelength band. Further, such a high-power laser is also attracting attention as a solid-state laser or a light source for exciting second harmonic light. AlGaAs ternary crystal is widely used as the material of the active region of the semiconductor used in this wavelength band. In the case of a laser device using this material as an active region, a large number of surface levels exist at the end face of the active layer exposed at the end face (cavity face) that forms the reflection surface of the resonator, and carriers of the Many non-radiative recombination. The carriers injected into the active layer near the cavity surface are lost by this recombination, and the carrier concentration is lower than that in the central portion. As a result, the active layer in the vicinity of the cavity surface becomes an absorption region for the maximum gain wavelength created by the high injected carrier density in the central portion, that is, the wavelength of the lasing laser light.
When the light density at the end face of the active layer increases to several megawatts per square centimeter during high-power operation, local heat generation in the absorption region eventually melts and destroys the cavity facet, causing the laser device to malfunction. It is generally known that Further, even if it is not destroyed in a short time, the oxidation reaction proceeds due to local heat generation at the end face of the active layer for a long time, which is a major cause of deterioration of device characteristics. In order to maintain a stable single transverse mode up to a high output, the width of the waveguide in the lateral direction must be a finite value of 5 to 6 μm or less, and in order to reduce the optical density of the end face of the active layer on the cavity surface. There is a limit. As described above, the surface level at the end face of the active layer has a significant influence on the high-power operation and the reliability during the high-power operation of the single transverse mode laser made of these materials.

The absorption of light on this resonator surface is reduced,
As a laser element that enables operation up to a higher output and stable operation at a high output, a laser element having a structure in the cavity direction called a window laser has been proposed and prototyped. This is a structure in which the energy gap of the semiconductor layer where the oscillation light is guided in the region near the cavity surface of the laser element is wider than the active layer, and the emission area of the cavity surface is transparent to the oscillation light. is there. As one specific manufacturing method thereof, there is known a method in which an active layer in a region forming a resonator surface is removed by etching, and a semiconductor having a wider energy gap than that of the active layer is crystal-grown therein. The oscillated light is emitted from the resonator surface through the embedded semiconductor layer (embedded guide layer), and the active layer is not exposed on the resonator surface. Therefore, it is possible to manufacture a semiconductor laser device that does not absorb light on the cavity surface and has a higher output and stable operation. Hereinafter, the region from which the active layer is removed is referred to as a window region, and the region having the active layer is referred to as a light emitting region.

The Japanese Journal of Applied Physics
Al of Applied Physics, Vol. 17 (1978), p. 865, Applied Physics Letters (Applied Physics)
Letters) 40 (1982) 1029,
Electronics Letters (Electronics)
An example of a window laser can be found in Letters, 20 (1984), p. 530. In these examples, the formation of the double hetero structure and the buried growth of the window region where the active layer was removed by etching were performed by the liquid phase epitaxial growth method. Since the liquid phase epitaxial growth method is a growth method in a thermal equilibrium state, it is easily affected by the surface state of the semiconductor to be grown. After removing the active layer by etching, the surface of the AlGaAs cladding layer is exposed to the atmosphere. Al easily oxidizes, and since the formed oxide film is thermally stable, liquid phase epitaxial growth method is effective on an AlGaAs layer whose aluminum composition exceeds 0.3 after being exposed to the air once and oxidized. It is generally known that it is difficult to grow a semiconductor layer having excellent crystallinity. Therefore, none of these conventional window laser devices have the expected high output characteristics and poor reproducibility of characteristics, and it is difficult to improve productivity.

On the other hand, in recent years, a metal organic chemical vapor deposition method has been put into practical use as a new growth method for semiconductor laser crystals. Metal-organic vapor phase epitaxy is a non-thermal equilibrium growth method,
By raising the growth temperature, a semiconductor layer having good crystallinity can be grown on the AlGaAs layer having an oxidized aluminum composition exceeding 0.3. Furthermore, compared to the liquid phase epitaxial growth method, the composition of the growth layer and the layer thickness are more controllable, and since film formation with a large area and high uniformity is possible, it has excellent ability to mass-produce laser elements with uniform characteristics. There is. Further, a semiconductor thin film having a layer thickness of 0.01 μm or less, which has been difficult to produce by the conventional liquid phase epitaxial growth method, can be formed relatively easily. Therefore, by introducing a quantum well structure in the active layer, It is also possible to improve the performance of the laser device by reducing the temperature and improving the temperature characteristics. IE
EE, Journal of Quantum Electronics (IEEE JOURNAL OF QUANTU
Volume 25 (1989) 14
On page 95, there is described a window laser device using metalorganic vapor phase epitaxy for the first time for buried growth for removing the active layer in the window region. However, in this example, the double hetero structure including the active layer was formed by the liquid phase epitaxial method.

Proceedings of the 50th Annual Meeting of the Applied Physics Society of Japan, 28p-ZG-10, 3rd volume, 899 pages (198)
9) describes a window laser device in which all semiconductor layers including an active layer having a quantum well structure are manufactured by a metal organic chemical vapor deposition method. FIG. 8 shows the sectional structure diagram.
Oscillation light from the MQW (multiple quantum well) active layer 105 is emitted from the resonator surface 40 through the n-guide layer 104 and the p-embedded guide layer 110 in the window region. Ga provided close to the upper part of the MQW active layer 105
The As n-light absorption current narrowing layer 108 limits the current to the stripe-shaped oscillation region and controls the transverse mode of the oscillation light. Also, the p-cap layer 112 in the window region
An oxide film (SiO ₂ ) 120 is formed on the top of the film to narrow the leakage current to the window region. The manufacturing method is as follows. First, a double hetero structure including an MQW active layer 105 on an n-GaAs substrate 101, an n-light absorption current narrowing layer 108,
After the n-etching mask layer 109 is uniformly grown, the MQW active layer 105 in the window region and the n-light absorption current narrowing layer 108 in the light emitting region are removed by wet etching. Next, the p-embedded guide layer 110, the p-embedded cladding layer 111, and the p-cap layer 112 are uniformly grown by regrowth. After forming the oxide film 120 in the window region, the pn electrodes 150 and 151 are formed and cleaved in the window region to form the cavity surface 40, thus completing the laser device.

[0007]

In the conventional laser structure, the leakage current to the window region is narrowed by the oxide film 120 formed on the p-cap layer 112.
However, since the oxide film 120 and the p-embedded guide layer 110 in the window region are separated by a distance of 1 μm or more, the effect of current narrowing is insufficient, and current leakage from the adjacent light emitting region is large. Especially, there is a possibility that current may leak remarkably through the p-cap layer 112 having a low electric resistance. Due to the reactive current not contributing to this oscillation, the threshold current was increased and the conversion efficiency was decreased, and a sufficiently high output characteristic was not obtained. Further, there is a possibility that reliability may be deteriorated due to heat generation in the window region due to the reactive current.

Further, in the conventional example, lateral mode control is performed by utilizing light absorption by the n-light absorption current narrowing layer 108 of GaAs. However, the light absorbed by GaAs causes a loss, which causes an increase in the oscillation threshold current and a decrease in the oscillation efficiency. Furthermore, due to the deterioration of the output characteristics due to heat generation due to absorption, the sufficiently high output operation expected as a window laser could not be obtained.

[0009]

(1) According to the present invention,
A semiconductor laser device using AlGaAs as a main material and a quantum well as an active layer, which is transparent to oscillation light and scatters oscillation light from the active layer remarkably in a region near a cavity surface including a laser cavity surface. An optical guide layer is formed instead of the active layer so as to guide the light without any action, and a current block layer, which is transparent to oscillated light and has a conductivity type different from that of the adjacent clad layer, is provided close to the optical guide layer. A semiconductor laser device characterized by the above is obtained.

(2) Further, according to the present invention, the lateral mode control structure of a semiconductor laser device is characterized in that a GaInP layer is provided on a side surface of a clad layer having a ridge shape. The device is obtained.

(3) Further, according to the present invention, there is provided a method of manufacturing a semiconductor laser using AlGaAs as a main raw material by a metal organic chemical vapor deposition method, wherein an active layer and a layer thickness of 0.5 μ above the active layer.
A double hetero semiconductor multilayer structure having a cladding layer of m or less is uniformly formed on a GaAs substrate, and the active layer in a region forming a resonator surface is removed by etching. The semiconductor laser device according to (1) above, wherein a semiconductor layer including a current blocking layer having a conductivity type different from that of the cladding layer is grown, and the current blocking layer on the active layer is removed by etching. A method of manufacturing is obtained.

(4) According to the present invention, when the current blocking layer is removed by etching, it is exposed above the active layer and the optical guide layer in the regions with and without the active layer. The method for manufacturing a semiconductor laser device according to the above (3) is obtained in which the layer thickness up to the surface of the semiconductor layer is the same.

(5) Further, according to the present invention, a GaInP layer which is thin enough not to disturb the electric field distribution of the oscillated light is provided under the active layer, and when the active layer is removed by etching, the GaInP layer is removed. Ga with an etching solution having an etching rate slower than that of the AlGaAs layer
The method of manufacturing a semiconductor laser device according to the above (3) or (4) is characterized in that etching is stopped in the InP layer.

[0014]

According to the present invention, by providing the current blocking layer in the vicinity of the light guide layer in the window region, the leakage current flowing into the window region can be minimized. Furthermore, since the current blocking layer is transparent to the oscillated light, there is no light loss even if it is provided close to the light guide layer, and the oscillated light can be extracted efficiently. Further, since the quantum well structure is adopted for the active layer, the oscillation threshold current is low, and device characteristics excellent in temperature characteristics can be expected.

Further, according to the present invention, the GaInP layer which does not absorb the oscillation light and has a low refractive index is provided on the side surface of the clad layer having the ridge shape, so that there is no light absorption in the lateral mode control. A refractive index guiding structure can be formed, and a window laser device having a low oscillation threshold current and high conversion efficiency can be obtained.

Further, according to the present invention, the thickness of the clad layer on the active layer is set to 0.5 μm or less at the time of forming the double hetero structure, so that in the etching for removing the active layer in the window region, It is possible to suppress variations in etching depth due to variations in layer thickness and etching rate to improve processing accuracy. As a result, it is possible to improve the uniformity of the oscillation characteristics of the completed laser device. Further, after removing the active layer, a current blocking layer that is transparent to oscillated light is formed in the vicinity of the light guide layer, whereby leakage current to the window region can be effectively prevented. In addition, it is possible to form a window region without loss of oscillation light. Further, by removing the current blocking layer formed on the active layer by etching, a structure in which current is injected only into the active layer in the light emitting region can be formed.

According to the method of manufacturing a window laser of the present invention, the center of the active layer and the light guide layer is used as a reference,
When the clad layer is processed into a ridge shape to form a lateral mode control structure by making the semiconductor layer thickness to the surface of the light emitting region and the window region the same, the center of the active layer and the bottom of the ridge in the light emitting region are formed. And the distance between the center of the light guide layer and the bottom of the mesa in the window region become the same in one etching, so that the effective refractive index in the lateral direction in both regions can be made substantially the same value. Therefore, a stable transverse mode control structure can be easily formed by the same design and manufacturing method as a laser device having no window structure.

Further, according to the present invention, GaI is formed under the active layer.
When a thin layer of nP is provided and the active layer in the window region is removed, the etching rate of the GaInP layer is AlGaA.
By using an etching solution slower than that of the s layer, the etching speed decreases when the etching depth reaches the GaInP layer, so that the etching depth can be accurately controlled without largely depending on time. Further, the AlGaAs layer having a layer thickness distribution within the wafer surface can be completely removed by lengthening the etching time within a time in which the GaInP layer is not completely removed by etching. As a result, it is possible to improve the in-plane uniform characteristics of the element characteristics, and it is possible to manufacture the window laser element with a high yield.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the Al according to claim 1 according to the present invention.
FIG. 3 is a cross-sectional view showing an example of the structure of a high-power semiconductor laser device whose main raw material is GaAs. The quantum well active layer 3 is composed of two layers of GaAs having a thickness of 0.008 μm as shown in FIG. 1b.
The quantum well layers 21 and 23 emit light having a wavelength in the 0.83 μm band which is widely used in optical disk devices. As shown in FIG. 1 a, the oscillation light of the quantum well active layer 3 is guided through the p-embedded guide layer (aluminum composition 0.37) 5 provided in the window region near the resonator surface 40, and the left and right resonator surfaces are guided. It is emitted from 40. p-embedded guide layer 5
Is transparent to the oscillated light, and the oscillated light is not absorbed by the resonator surface 40, so that it can operate stably up to a high output without being destroyed by heat generation. Further, the centers of the quantum well active layer 3 and the p-buried guide layer 5 coincide with each other at the boundary between the light emitting region and the window region, and the oscillation light in the light emitting region is guided in the window region without being largely scattered. Also p-
Cladding layer (aluminum composition 0.42) 4, 6 and 8
An n-current blocking layer 7 having the same aluminum composition and different conductivity type is provided in the vicinity of a 0.3 μm position on the optical guide layer 5 in the window region to effectively prevent the leakage current flowing into the window region. Can be suppressed to
At the same time, since the n-current blocking layer 7 does not absorb the oscillation light, it does not deteriorate the oscillation characteristics of the laser element.

FIG. 2 shows an embodiment of the structure of the high power semiconductor laser device according to the second aspect of the present invention. Figure 2a
Is processed into a ridge shape on the p-cladding layer side of the laser device having the structure illustrated in FIG. 1, and the side surface of the ridge is n-Ga.
It has a structure in which the InP layer 25 is embedded. The width of the ridge is 4 μm. The n-GaInP layer 25 squeezes the current in the ridge region and at the same time does not absorb the oscillation light of 0.83 μm, and has a lower refractive index than the p-cladding layers 4, 6 and 8, so that the actual refractive index guiding is achieved. The transverse mode control structure of is formed and high conversion efficiency is obtained. FIG. 2b shows a cross-sectional structural view of the light emitting region.

FIG. 3 and FIG. 4 show an embodiment of a method of manufacturing a high power laser device using AlGaAs as a main raw material according to the third aspect of the present invention. First, as shown in FIG. 3a, an n-clad layer (aluminum composition 0.42) 2 having a layer thickness of 1.5 μm, a quantum well active layer 3, a layer thickness of 0. 4 μm
The double-hetero structure of the p-cladding layer (aluminum composition 0.42) 4 is uniformly grown. Growth temperature is 760 ℃
Is. As shown in FIG. 1b, the quantum well active layer 3 has a barrier layer (aluminum composition of 0.
3) 22 is a GaAs quantum well 2 with a layer thickness of 0.008 μm
It has a two-layer quantum well structure in which it is sandwiched between 1 and 23, and the outside is further sandwiched between guide layers (aluminum composition 0.3) 20 and 24 having a layer thickness of 0.06 μm. Next, in order to form the window region, a stripe-shaped resist mask having a width of 900 μm is formed in the <0-11> direction on the p-clad layer 4 by using a photolithography technique. A phosphoric acid-based etching solution (H ₂ PO ₄ : H ₂ O ₂ : H ₂ O =
By 1: 1: 5), the quantum well active layer 3 is completely removed by etching at room temperature of 20 ° C. for about 10 seconds.

This etching is performed to a depth of 0.03 μm in the n-clad layer 2 as shown in FIG. By over-etching to the position shown in FIG. 6, the center of the quantum well active layer 3 and the center of the p-embedded guide layer 5 coincide with each other when the p-embedded guide layer 5 is formed by the next crystal growth. The light coupling efficiency at the boundary between the light emitting region and the window region can be increased to 90% or more.

FIG. 3b is a diagram showing the state after etching. On top of this, as shown in FIG.
-Embedded guide layer (aluminum composition 0.37) 5,
A p-first buried clad layer (aluminum composition 0.42) 6 having a layer thickness of 0.3 μm and an n-current blocking layer (aluminum composition 0.42) 7 having a layer thickness of 0.3 μm were similarly formed by metal organic chemical vapor deposition. grow up. The growth temperature is 800 ° C. Then, using lithography technology, <0-11>
Direction, a stripe-shaped window of resist is formed on the light emitting region, and etching is performed to a depth of 0.3 μm from the surface of the n-current blocking layer 7 with a phosphoric acid-based etching solution. By this etching, the n-current blocking layer 7 is removed in the light emitting region, and a current is injected into the quantum well active layer 3. At the same time, a structure in which no current flows is formed in the window region.

FIG. 4d shows the view after etching.
On this, as shown in FIG. 4e, a p-second layer having a layer thickness of 0.7 μm is formed.
Buried clad layer (aluminum composition 0.42) 8,
The p-cap layer (GaAs) 9 having a layer thickness of 0.5 μm was grown again by the metal organic chemical vapor deposition method to complete the window laser structure. Next, on the p-cap layer 9, S having a thickness of 0.3 μm is formed.
The iO ₂ film 30 is formed by ion beam sputtering, and <0-
After opening a window with a width of 50 μm in the 1-1> direction, both pn electrodes 50 and 51 are formed on the entire surface, and in the window region <
The resonator face 40 was formed by cleavage in the 0-11> direction. FIG. 4f shows the completed window laser device.

FIG. 5 shows an embodiment of a method for manufacturing a high-power laser device according to claim 4 of the present invention. In the method of manufacturing the laser device illustrated in FIGS. 3 and 4, when the n-current blocking layer 7 in the light emitting region is removed by etching, the p-first buried cladding layer 6 is further overetched to a depth of 0.1 μm. To do. Due to this over-etching, the layer thickness from the center of the quantum well active layer 3 to the surface of the light emitting region and the layer thickness from the center of the p-embedded guide layer 5 to the surface of the window region, which are indicated by t in FIG. Will be the same. As shown in FIG. 5b, a p-second buried clad layer (aluminum composition 0.42) 8 having a layer thickness of 0.7 μm and a p layer having a layer thickness of 0.5 μm are formed thereon.
The cap layer 9 is grown again by metalorganic vapor phase epitaxy.
Even after the growth, the layer thickness from the center of the quantum well active layer 3 and the p-buried guide layer 5 to the surfaces of the light emitting region and the window region is 2.1 μm, which is almost the same. A ridge having a width of 4 μm is formed on the p-cladding layer side by photolithography and wet etching to <0-1-
After being formed in the 1> direction, an n-GaInP layer 25 was embedded in the side surface of the ridge by a metal organic chemical vapor deposition method to prepare a lateral mode control structure. The pn electrodes 50 and 51 are formed and cleaved in the <0-11> direction in the window region to form the resonator surface 4
Formed 0. FIG. 5c shows the finished laser device.

FIG. 7 shows an embodiment of a method of manufacturing a high power semiconductor laser device according to the fifth aspect of the present invention. When forming the double hetero structure, an n-GaInP etching stop layer 10 having a layer thickness of 0.001 μm is provided in the n-clad layer 2 having a thickness of 0.03 μm below the quantum well active layer 3 as shown in FIG. 7A. . When the active layer in the window region is removed, an aqueous solution of bromic acid is used as an etching solution, so that GaInP
Since the etching rate is slow in the layer, the etching depth does not largely depend on the etching time, and the etching depth can be always kept in the thin n-GaInP etching stop layer 10 as shown in FIG. 7b. In addition, by extending the etching time until the n-GaInP etching stop layer 10 is completely removed by etching,
The influence of the layer thickness of the p-cladding layer 4 on the P layer etching stop 10 and the in-plane non-uniformity of etching can be suppressed to a small level. As a result, it is possible to perform accurate and uniform etching processing within the wafer surface, and it is possible to improve the productivity of laser elements.

[0027]

FIG. 9 shows current-light output characteristics of the window laser device manufactured according to the embodiment shown in FIG. No coating was applied to the cavity surface. The oscillation threshold current was 0.05 A, the conversion efficiency on one side was 0.55 W / A, and the maximum optical output was 0.34 W. The present invention enables a low threshold current, high efficiency, and high output operation, which were not obtained in the conventional example. Further, the uniformity of the oscillation characteristics within the wafer surface was also good.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a high-power semiconductor laser device which is an embodiment of the invention described in claim 1.

FIG. 2 is a diagram showing a structure of a high-power semiconductor laser device which is an embodiment of the invention described in claim 2;

FIG. 3 is a diagram showing a method of manufacturing a high-power semiconductor laser device which is an embodiment of the invention described in claim 3.

FIG. 4 is a diagram showing a method of manufacturing a high-power semiconductor laser device which is an embodiment of the invention described in claim 3;

FIG. 5 is a diagram showing a method of manufacturing a high-power semiconductor laser device which is an embodiment of the invention described in claim 4.

FIG. 6 is a diagram showing a state of etching an active layer in a window region in a semiconductor laser which is an embodiment of the invention described in claim 3;

FIG. 7 is a diagram showing a state of etching an active layer in a window region in a semiconductor laser which is an embodiment of the invention described in claim 5;

FIG. 8 is a diagram showing a structure of a conventional high-power semiconductor laser device.

FIG. 9 is a diagram showing an effect of the embodiment of FIG.

[Explanation of symbols]

1 n-GaAs substrate 2 n-clad layer (aluminum composition 0.42) 3 quantum well active layer 4 p-clad layer (aluminum composition 0.42) 5 p-embedded guide layer (aluminum composition 0.3
7) 6 p-first buried cladding layer (aluminum composition 0.42) 7 n-current blocking layer (aluminum composition 0.4)
2) 8 p-second embedded cladding layer (aluminum composition 0.42) 9 p-cap layer (GaAs) 10 n-GaInP etching stop layer 20,24 guide layer (aluminum composition 0.3) 21,23 GaAs quantum well Layer 22 Barrier layer (aluminum composition 0.3) 25 n-GaInP layer 30 SiO ₂ film 40 Resonator surface 50 n-electrode 51 p-electrode 101 n-GaAs substrate 102 n-buffer layer 103 n-clad layer 104 n- Guide layer 105 MQW active layer 106 p-cladding layer 107 p-ILA layer 108 n-photoabsorption current narrowing layer (GaAs) 109 n-etching mask layer 110 p-embedded guide layer 111 p-embedded cladding layer 112 p-cap Layer 120 Oxide film 150 n-electrode 151 p-electrode

Claims (5)

[Claims] 1. A semiconductor laser device using AlGaAs as a main material and a quantum well as an active layer, wherein the semiconductor laser device is transparent to oscillated light in a region near a cavity surface including a laser cavity surface. An optical guide layer is formed instead of the active layer to guide the oscillated light without significantly scattering it, and further, a current block layer that is transparent to the oscillated light and has a conductivity type different from that of the adjacent clad layer is the optical guide layer. A semiconductor laser device characterized in that it is provided close to the. 2. The semiconductor laser device according to claim 1, wherein a GaInP layer is provided on a side surface of the clad layer having a ridge shape. 3. AlGaAs is used as a main material, a quantum well is used as an active layer, and in a region near a cavity surface including a laser cavity surface, it is transparent to the oscillation light and the oscillation light from the active layer is significantly scattered. An optical guide layer is formed instead of the active layer so as to guide the light without any action.In addition, a current block layer that is transparent to oscillation light and has a conductivity type different from that of the adjacent clad layer is close to the optical guide layer. In the method of manufacturing a provided semiconductor laser device, a double hetero semiconductor multilayer structure having an active layer and a clad layer having a layer thickness of 0.5 μm or less above it is uniformly formed on a GaAs substrate to form a cavity surface. After removing the active layer in the region to be etched by etching, a semiconductor layer including a current blocking layer which is transparent to the oscillated light and has a conductivity type different from that of the adjacent clad layer is grown. A method of manufacturing a semiconductor laser device, wherein the current blocking layer on the active layer is removed by etching. 4. When removing the current blocking layer by etching, the layer thickness up to the surface of the semiconductor layer exposed above in the region with and without the active layer with respect to the center of the active layer and the light guide layer, respectively. 4. The method for manufacturing a semiconductor laser device according to claim 3, wherein the same are set. 5. A GaInP layer, which is thin enough not to disturb the electric field distribution of the oscillated light, is provided close to the active layer, and the GaInP layer is removed when the active layer is removed by etching.
5. The method of manufacturing a semiconductor laser device according to claim 3, wherein the etching is stopped in the GaInP layer by using an etching solution having an etching rate slower than that of the AlGaAs layer.