JPH0621568A - Semiconductor laser device and its manufacture - Google Patents

Abstract

PURPOSE:To provide a semiconductor laser device and its manufacturing method wherein single mode oscillation is obtained by low operation current driving, and high reliability is realized, in the case of operation of high output larger than or equal to 100mW which is necessary for a light source of optical recording, solid-state laser pumping, etc. CONSTITUTION:On a conductivity type Ga1-BAlBAs layer turning to an optical guide layer 4, a Ga1-XAlXAs layer turning to an active layer except he vicinity of an end surface is formed. On the active layer 5, a Ga1-CAlCAs layer turning to a light confinement layer 6 of the conductivity type opposite to the optical guide layer 4 and a Ga1-DAlDAs layer turning to a protective layer 7 is formed. On the optical guide layer 4 in the vicinity of the end surface and the protective layer 7, a first clad layer 8 of Ga1-Y1AlY1As and a second clad layer 9 of Ga1-Y2 AlY2As which have the conductivity type opposite to the optical guide layer 4 are formed in order. Further on the second clad layer 9, a current block layer 19 of Ga1-ZAlZAs which has the conductivity type opposite to the layer 9 and is provided with a stripe type window 10a is formed. The stripe type window 10a is provided with a Ga1-Y3AlY3As layer 12 of the same conductivity as the clad layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device which is required as a light source for optical recording and excitation of a solid-state laser and which oscillates in a single mode at a high power operation of 100 mW or more, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in application fields such as optical disk memory, optical recording, and light source for solid-state laser excitation, there has been a demand for a semiconductor laser device having a low operating current drive and a single mode oscillation and high reliability during high output operation. Has been done. The reduction in operating current of the semiconductor laser device is realized by reducing the internal loss and the reflection loss. Particularly, it is important to reduce the internal loss, and FIG. 6 shows an example of a conventional semiconductor laser device having a low operating current (Japanese Patent Laid-Open No. 62-73687). n-type Ga _{0. 65} A on the n-type GaAs substrate 15 of the
l _0.35 As clad layer 16, GaAs active layer 17, and p-type Ga _0.75 Al _0.25 As first clad layer 18, and n-type due to current confinement in parts other than the stripe-shaped window 19a which becomes a current channel. Ga _0.51 Al _0.49 As current blocking layer 19 is formed. 20, p-type Ga _0.75 Al _{0. 25} As second clad layer formed by regrowth, 21 is a p-type GaAs contact layer.

In the structure of FIG. 6, the current injected from the p-type GaAs contact layer 21 is effectively confined in the window 19a, and laser oscillation occurs in the GaAs active layer 17 below the window 19a. At this time, n-type Ga _0.51 Al _0.49
The refractive index of the As current blocking layer 19 is p-type Ga _0.75 A
The refractive index is smaller than that of the l _0.25 As second cladding layer 20, and the laser light is also effectively confined in the window 19a. Also, the forbidden band width of the n-type Ga _{0. 51} Al _0.49 As current blocking layer 19, than the band gap of the GaAs active layer 17, sufficiently so large, the n-type with respect to the laser beam Ga
_{The 0.51} Al _0.49 As current blocking layer 19 becomes transparent, and a low operating current driven semiconductor laser with small internal loss can be obtained. Along with this, a semiconductor laser device having a high reliability is obtained by performing a light output operation of 30 mW. The oscillation wavelength of this semiconductor laser device is in the 870 nm band because the active layer 17 is GaAs.

[0004]

Since it is difficult to re-grow in the semiconductor laser device having the above-mentioned conventional structure, a p-type G laser diode is used.
a _0.75 Al _0.25 As Since the AlAs mixed crystal ratio of the first cladding layer 18 cannot be increased, there is a problem that the temperature characteristics are poor. Therefore, there is a problem that a laser in the visible region of 780 nm band cannot be easily realized. That is, when re-growth is performed on GaAlAs having a high AlAs mixed crystal ratio, the crystallinity of the re-growth interface deteriorates due to a problem of surface oxidation, and a defect occurs in the current-voltage characteristics. This is because it is necessary to lower the mixed crystal ratio to some extent. For easy fabrication, the AlAs mixed crystal ratio needs to be 0.3 or less, but since the confinement of carriers in the active layer is limited, a semiconductor laser device having excellent temperature characteristics cannot be obtained. In particular, the AlAs of the clad layer
Laser oscillation in the visible region, which requires a mixed crystal ratio of about 0.5,
In this case, it is difficult. Further, at the time of high output operation of 100 mW or more, it is difficult to obtain high reliability due to optical damage (COD) on the end face.

The present invention solves the above problems, improves the temperature characteristics, and can be easily manufactured even in the visible region.
It is an object of the present invention to provide a semiconductor laser device having a low operating current value, which has high reliability and oscillates in a single mode even when operating at a high output of 100 mW or more.

[0006]

In order to achieve the above object, a semiconductor laser device of the present invention comprises a Ga _{1 -B} Al _B As layer of one conductivity type which serves as an optical guide layer, except for the vicinity of the end face. A Ga _1-x Al _x As layer serving as an active layer, and a Ga _{1 -c} Al _c As layer serving as a light confining layer of a conductivity type opposite to the light guide layer and a protective layer on the active layer. Ga _1-D Al _D
There is an As layer, and Ga _{1 -Y 1} Al _{Y 1} of a conductivity type opposite to that of the light guide layer is provided on the light guide layer near the end face and the protection layer.
An As first clad layer and a Ga _{1 -Y2} Al _Y2 As second clad layer are provided in this order, and G having a striped window of the opposite conductivity type to the above second clad layer.
An a _1-Z Al _Z As current blocking layer is formed, and the striped window is provided with a Ga _{1 -Y 3} Al _{Y 3} As layer of the same conductivity type as the cladding layer.
Between X, Y1, Y2, Y3 and Z, Z>Y3> Y2
It has a structure in which the relationship of> X ≧ 0, Y1> Y2 is established.

[0007]

With this structure, the confinement of carriers in the active layer is determined by the Ga _{1 -Y1} Al _Y1 As first cladding layer having a high AlAs mixed crystal ratio, and the re-growth is Ga ₁ -Y2 having a low AlAs mixed crystal ratio. Since the growth is on the Al _Y2 As second clad layer, the regrowth can be easily performed. Further, by introducing a window structure having a material transparent to the laser beam oscillated in the end surface portion, deterioration of the end surface can be prevented and high reliability can be obtained even during high power operation of 100 mW or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a window according to an embodiment of the present invention.
It is a cross-sectional view of a C-shaped semiconductor laser device. Resonator active layer
Light is taken from the light guide layer below the active layer without exposing it to the end face.
Taking a window type semiconductor laser device as an example,
I raised it. 1A is a perspective view of the element, and FIG. 1B is FIG.
(A) Internal cross-sectional structure divided along A-A '
It is a drawing. On the n-type GaAs substrate 1, n-type Ga
An As buffer layer 2 is formed, and n-type G is formed on the As buffer layer 2.
a_0.6Al_0.4As clad layer 3, n-type Ga_{0. 7}Al_0.3
As (generally Ga_1-BAl_BLight guide layer (denoted by As)
4 on which Ga is removed only near the end face_0.92
Al_0.08As (generally Ga_1-XAl_X(Expressed as As)
The functional layer 5 is formed. Laser oscillation is generated in the active layer 5.
Then, it is guided by the light guide layer 4 and emitted from the end face. this
At this time, the active layer 5 is not exposed at the end face and the active layer 5 is not exposed at the end face.
COD does not occur due to the conductive layer 5. On the active layer 5,
Confine carriers and light in the active layer 5 and the light guide layer 4.
P-type Ga for_0.5Al_{0 .Five}As (generally Ga_1-CA
l_CThere is a light confinement layer 6 (denoted by As), on which
P-type Ga for regrowth_0.8Al_0.2As (generally G
a_1-DAl_DA protective layer 7 (denoted by As) is formed.
On the protective layer 7 inside and on the light guide layer 4 on the end face.
Is p-type Ga_0.6Al_0.4As (generally Ga_1-Y1Al
_Y1First clad layer 8, p-type Ga (represented by As)_0.8A
l_0.2As (generally Ga_1-Y2Al_Y2Represented by As)
The two-clad layer 9 is formed, and the current is confined due to the current confinement.
In the area other than the window 10a which becomes the flow channel, an n-type G
a_0.4Al_0.6As (generally Ga_{1- Z}Al_ZExpressed as As
The current blocking layer 10 is formed. 11 is
Ga_{0. 8}Al_0.2As protective layer, 12 is p-type Ga_0.6Al
_0.4As (generally Ga_1-Y3Al _Y3Represented by As) Third
The cladding layer 13 is a p-type GaAs contact layer
It

Here, in order to obtain stable single transverse mode oscillation, the AlAs mixed crystal ratio of the current block layer 10 is set to p-type G.
It is set higher than the AlAs mixed crystal ratio of the a _0.6 Al _0.4 As third cladding layer 12 by 10% or more. If the AlAs mixed crystal ratio of the current blocking layer 10 is similar to that of the cladding layer,
Since there is a decrease in the refractive index within the stripe due to the plasma effect, the waveguide becomes an antiguide waveguide, and a single transverse mode oscillation cannot be obtained. In other words, AlA of the current blocking layer 10
When the s crystal ratio is lower than that of the third clad layer 12, the transverse mode becomes completely unstable, and even the target low operating current cannot be achieved. In the present embodiment, as shown in FIG. 1, the AlAs mixed crystal ratio of the current blocking layer 10 is set to p-type Ga.
_{It is set to 0.6} , which is about 0.2 higher than the AlAs mixed crystal ratio of the _0.6 Al _0.4 As third clad layer 12.

In this structure, the current injected from the p-type GaAs contact layer 13 is confined in the window 10a, and the Ga _0.92 Al _0.08 As active layer 5 below the window 10a.
Laser oscillation occurs. Here, p-type Ga _0.5 Al _0.5
The AlAs mixed crystal ratio of the As optical confinement layer 6 is A of the active layer 5.
It is sufficiently higher than the 1As mixed crystal ratio, effectively confining carriers in the active layer 5 and enabling laser oscillation in the visible region.
The refractive index of Ga _0.4 Al _0.6 As current blocking layer 10 of n-type, Ga _{0 .6} Al _0.4 of p-type internal current channel
Since the refractive index is sufficiently smaller than the refractive index of the As third cladding layer 12, the laser light is confined in the window 10a due to this refractive index difference, and a single transverse mode laser light is obtained.

The re-growth is performed by n-type Ga _0.7 Al _0.3 As optical guide layer 4 having an AlAs mixed crystal ratio of 0.3 or less and p-type Ga.
_0.8 Al _0.2 As protective layer 7 and p-type Ga _0.8 Al _0.2 As
Since it is grown on the second cladding layer 9, there is no problem of surface oxidation.

P type Ga _0.8 Al _0.2 As protective layer 7 and p
The layer thickness of the Ga _0.8 Al _0.2 As second clad layer 9 of the mold is preferably 0.05 μm or less, which has almost no effect on the light distribution, and is 0.01 μm in this embodiment. As described above, oscillation in the visible region is possible by specially forming the regrown semiconductor layer.

Since the forbidden band width of the n-type Ga _0.4 Al _0.6 As current blocking layer 10 is larger than the forbidden band width of the Ga _0.92 Al _0.08 As active layer 5, there is no light absorption by the current blocking layer 10. The loss of the waveguide can be greatly reduced, and the operating current can be reduced.

In this structure, since there is no light absorption by the current blocking layer 10, the laser light is n-type Ga _0.4 Al _0.6 A.
It spreads to the lower part of the s-current blocking layer 10, the spectrum is likely to be multimode, and a low-noise laser can be easily obtained.

Generally, A in the above chemical formula
lAs mixed crystal ratio, between X, Y1, Y2, Y3 and Z,
The relations of Z>Y3>Y2> X ≧ 0 and Y1> Y2 may be established.

FIG. 2 is a manufacturing process diagram of a semiconductor laser device according to an embodiment of the present invention. As shown in FIG. 2A, an n-type GaAs buffer layer 2, an n-type Ga _0.6 Al _0.4 As clad layer 3, and an n-type GaAs buffer layer 2 are formed on the n-type GaAs substrate 1 by MOCVD or MBE. Ga _0.7 A
l _0.3 As light guide layer 4, Ga _0.92 Al _0.08 As active layer 5, p-type Ga _0.5 Al _0.5 As light confinement layer 6, and p-type Ga _0.8 Al _0.2 As protective layer 7 are formed. This protective layer 7
Is necessary to protect the upper portion of the p-type Ga _0.5 Al _0.5 As optical confinement layer 6 through which current flows from surface oxidation. Figure 2
The conductivity type of the active layer is not particularly described, but may be p-type, n-type, or of course undoped.

Next, as shown in FIG. 2B, the active layer 5, the optical confinement layer 6 and the protective layer 7 on the end face are removed by etching, and then p-type Ga _0.6 Al is formed by MOCVD or MBE. _0.4 As first cladding layer 8, p-type Ga _0.8 Al _0.2 As second cladding layer 9, n-type Ga _0.4
Al _0.6 As current blocking layer 10 and Ga _0.8 Al _0.2 A
The s protective layer 11 is formed. At this time, when Zn is used as a dopant in regrowth of the p-type semiconductor layer,
Zn active region (especially when active region has quantum well structure)
Since the influence of diffusion during growth on the characteristics may be considered, the carrier concentration should be at least 1 at the regrowth interface.
It must be 0 ¹⁸ cm ^-3 or less.

Subsequently, as shown in FIG. 2C, the stripe-shaped window 10a is formed by photolithography.
It is formed by etching. As an etching method, first, an n-type Ga is used as an etchant that is not very selective with respect to an AlAs mixed crystal ratio such as tartaric acid or sulfuric acid.
Etching is performed up to the middle of the _0.4 Al _0.6 As current blocking layer 10. Furthermore, AlAs such as hydrofluoric acid type and phosphoric acid type
Only the n-type Ga _0.4 Al _0.6 As current blocking layer 10 is selectively etched using an etchant that selectively etches the semiconductor layer having a high mixed crystal ratio. That is, the p-type Ga _0.8 Al _0.2 As second cladding layer 9 also functions as an etching stop layer. Therefore, variations due to etching are small, and a high yield can be obtained.

Here, the stripe shape is preferably a forward mesa shape rather than an inverted mesa shape. In the case of the inverted mesa shape, crystal growth is more difficult than in the case of the normal mesa shape, and there is a possibility that the yield may be reduced due to the deterioration of the characteristics.

With respect to the thickness of the current blocking layer 10, if the thickness of the current blocking layer 10 is thin, light absorption of laser light will occur in the p-type GaAs contact layer 13 on the upper side. 0.4 μm is necessary.

Finally, as shown in FIG. 2D, MOCV
P-type Ga by D method or MBE method_0.6Al_0.4A
s Third cladding layer 12, p-type GaAs contact layer 1
3 to form n-type GaAs substrate 1 and p-type GaA
An electrode 14 is formed on each of the s contact layers 13.
At this time, the AlAs mixed crystal is present in the stripe in which the current flows.
Low ratio p-type Ga_0.8Al_0.2As on the second clad layer 9
Since it is the re-growth, it can be easily grown. At this time,
Zn as a dopant in regrowth of p-type semiconductor layer
If used, Zn is spread over the stripe region during growth.
At least,
A carrier concentration of 10 at the regrowth interface ¹⁸cm^-3The following
Need to

FIG. 3 is a current-light output characteristic diagram of the semiconductor laser device in one embodiment of the present invention. For comparison,
The characteristics of the conventional semiconductor laser device are also shown. In the semiconductor laser device of the present invention, the end face deterioration does not occur, and
A light output of 0 mW or more can be obtained.

FIG. 4 shows the relationship between spectral characteristics and structural parameters in one embodiment of the present invention. Active layer thickness (d
a), in a wide range of the first cladding layer thickness (dp),
It can be seen that multimode oscillation is obtained. Since there is no light absorption by the current blocking layer, multimode oscillation is obtained even in a region where da and dp are thin. Since dp may be thin, a low-noise semiconductor laser device can be obtained in a state where leakage current to the outside of the stripe is small, and since da can be thin, a low-noise semiconductor laser device capable of high-output operation. Moreover, since da may be thin, a semiconductor laser device capable of high-power operation with low noise can be realized.

FIG. 5 shows the relationship between the stripe width (width of the window 10a) and the operating current value. In the structure of the present invention, when the stripe width is narrowed, the operating current value is further reduced. Here, in the case where the stripe width is narrowed in the structure of the present invention, the light seeping out to the current block layer is relatively increased as compared with the light inside the stripe, so that the multimode property of the spectrum is further improved. ,Become stronger. That is, narrowing the stripe width results in lower noise.

In all of the above embodiments, if the active layer has a quantum well structure, the operating current value can be further reduced, and a higher output can be achieved. Here, the quantum well structure includes all structures having a quantum effect. Single quantum well structure (SQW), multiple quantum well structure (MQ
W), and all of the cases where the separate confinement structure (SCH structure) is formed.

In the above embodiments, the substrate is n-type and only the n-type current blocking layer is used. However, the substrate may be p-type and p-type current blocking layer may be used. . This is because the AlAs mixed crystal ratio of the current blocking layer is high, so that the diffusion of electrons is suppressed and the carriers can be blocked by the p-type semiconductor layer.

[0028]

As described above, according to the present invention, a Ga _{1 -B} Al _B As layer of one conductivity type that serves as an optical guide layer is formed on the Ga _{1 -X} Al _X As layer that serves as an active layer except in the vicinity of the end face. There is a layer, and on the active layer, a Ga _1-C Al _C As layer that becomes an optical confinement layer of a conductivity type opposite to the light guide layer and a Ga _1-D layer that becomes a protective layer are provided.
There is an Al _D As layer, and Ga ₁ -Y _{1 having} a conductivity type opposite to that of the light guide layer is provided on the light guide layer near the end face and the protection layer.
Al _Y1 As first clad layer, Ga _1-Y2 Al _Y2 As second clad layer sequentially, with comprising, Ga ₁ on said second cladding layer, having a stripe-like window in the conductivity type opposite to this _-Z Al _Z As current blocking layer is formed,
The striped window is provided with a Ga _{1 -Y 3} Al _Y3 As layer having the same conductivity type as the cladding layer, and Z> Y3 between the AlAs mixed crystal ratios, X, Y1, Y2, Y3 and Z. >
Due to the structure satisfying the relations of Y2> X ≧ 0 and Y1> Y2, it has excellent temperature characteristics, can be easily manufactured even in the visible region, and has high reliability with single mode oscillation during high output operation of 100 mW or more. A semiconductor laser device having a low operating current value can be provided.

That is, the existence of the optical confinement layer having a high AlAs mixed crystal ratio and the first cladding layer effectively confine carriers in the active layer, and all the re-growth results in growth into a semiconductor layer having a low AlAs mixed crystal ratio. A semiconductor laser device in the visible region can be easily manufactured.

Further, since the selective etching method by the difference in AlAs mixed crystal ratio can be used for the etching for forming the stripe-shaped window, the variation in etching is reduced and a high yield can be obtained.

Further, since the AlAs mixed crystal ratio of the current block layer is set higher than the AlAs mixed crystal ratio of the cladding layer, oscillation occurs in a single transverse mode, and laser light is absorbed by the current block layer. Therefore, low operating current driving is realized, and by introducing a window structure in the cavity end face portion, an optical output operation of 100 mW or more becomes possible.

Since the reduction of the operating current value leads to the reduction of the heat generation amount in the active layer and the heat generation amount of the laser mount portion, the high output operation of 300 mW or more is also possible. In addition, a small and lightweight heat sink can be used,
As an example thereof, the laser package, which is conventionally made of metal, can be realized by using the semiconductor laser device of the present invention, and the pickup of an optical disk or the like can be greatly downsized and the cost can be reduced.

In the present invention, all the crystal growth steps are carried out by MO.
Since the CVD method is used, a desired semiconductor laser can be manufactured with a high yield.

[Brief description of drawings]

FIG. 1A is a perspective view of a semiconductor laser device according to an embodiment of the present invention. FIG. 1B is a sectional view taken along the line AA ′ of the semiconductor laser device of FIG.

FIG. 2 is a process perspective view showing a method of manufacturing the semiconductor laser device of FIG.

FIG. 3 is a current-light output characteristic diagram of the semiconductor laser device of FIG.

FIG. 4 is a diagram showing a relationship between spectral characteristics and structural parameters of the semiconductor laser device of FIG.

5 is a diagram showing the relationship between the operating current value and the stripe width of the semiconductor laser device of FIG.

FIG. 6 is a sectional view of a conventional semiconductor laser device.

[Explanation of symbols]

1 n-type GaAs substrate (one conductivity type semiconductor substrate) 2 n-type GaAs buffer layer 3 n-type Ga _0.6 Al _0.4 As clad layer 4 n-type Ga _0.7 Al _0.3 As optical guide layer (one conductivity-type Ga _1-B Al _B As optical guide layer) 5 Ga _0.92 Al _0.08 As active layer (Ga _1-X Al _X As
Active layer) 6 p-type Ga _0.5 Al _0.5 As optical confinement layer (reverse conductivity Ga _{1 -C} Al _C As optical confinement layer) 7 p-type Ga _0.8 Al _0.2 As protective layer (reverse conductivity G
a _1-D Al _D As protective layer) 8 p-type Ga _0.6 Al _0.4 As first clad layer (reverse conductivity type Ga _1-Y1 Al _Y1 As first clad layer) 9 p-type Ga _0.8 Al _0.2 As first Two clad layers (reverse conductivity type Ga ₁ -Y ₂ Al _{Y 2} As second clad layer) 10 n type Ga _0.4 Al _0.6 As current blocking layer (one conductivity type Ga ₁ -Z Al _Z As current blocking layer) 10 a stripe Window 11 Ga _0.8 Al _0.2 As protective layer 12 p-type Ga _0.6 Al _0.4 As third cladding layer (reverse conductivity Ga _{1 -Y 3} Al _{Y 3} As third cladding layer) 13 p-type GaAs contact layer 14 electrode

Front page continuation (72) Inventor Kunio Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (3)

[Claims] 1. A device formed on a semiconductor substrate of one conductivity type.
Conductive Ga_1-BAl_BAs light guide layer and its light guide
Ga formed on the layer excluding the vicinity of the end face _1-XAl_X
As active layer and a reverse conductive layer formed on the active layer in sequence.
Electric type Ga_1-CAl_CAs optical confinement layer and Ga_1-DAl_D
The As protective layer and the protective layer and the protective layer are formed.
Inverse conduction sequentially formed on the light guide layer
Electric type Ga_1-Y1Al_Y1As first clad layer and Ga_1-Y2
Al_Y2As second clad layer and on the second clad layer
One conductivity type Ga having a striped window_1-ZAl_ZAs
In the area including the current blocking layer and the stripe-shaped window
Reverse conductivity type Ga formed_1-Y3Al_Y3As third clad
And a layer, at least AlAs mixed crystal ratio, X, Y1, Y
2, between Y3 and Z, Z> Y3> Y2> X ≧ 0, Y
A semiconductor laser characterized in that a relation of 1> Y2 is established.
The device. 2. The semiconductor laser device according to claim 1, wherein the Ga _1-x Al _x As active layer is an active layer having a quantum well structure. 3. One conductivity type G on a one conductivity type semiconductor substrate.
a _1-B Al _B As optical guide layer, Ga _1-X Al _X As active layer,
Reverse conductivity type Ga _{1 -C} Al _C As optical confinement layer and Ga
A step of sequentially forming a _1-D Al _D As protective layer by an epitaxial growth method, a step of etching the end face portions of the protective layer, the light confinement layer and the active layer, and a step of exposing the end face portion of the light guide layer by etching. And a reverse conductivity type Ga ₁ -Y ₁ Al _{Y 1} As first clad layer, a reverse conductivity type Ga ₁ -Y ₂ Al _{Y 2} As second clad layer, and a _single conductivity type G on the protective layer.
a _1-Z Al _Z As current blocking layers are sequentially stacked by an epitaxial growth method, only the current blocking layers are selectively etched in a stripe shape, and a region including a portion selectively etched in a stripe shape is reversed. At least forming a conductive type Ga _{1 -Y 3} Al _{Y 3} As third cladding layer by an epitaxial growth method.
Between the mixed crystal ratios X, Y1, Y2, Y3 and Z, Z> Y
A method of manufacturing a semiconductor laser device, wherein the relations of 3>Y2> X ≧ 0 and Y1> Y2 are established.