JP2003179306A - Semiconductor laser element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser element of high output by improving break down light output, and its manufacturing method. <P>SOLUTION: Both end surfaces of the semiconductor laser element in the length direction turn to a laser output side end surface 15 and a reflection side end surface 16, respectively. A lower part clad layer 2, an active layer 3, an upper part first clad layer 4 and an etching stop layer 5 are laminated in order on a substrate 1. On the etching stop layer 5, an upper part second clad layer 7 of a ridge type is formed along the element length direction. Current block layers 6 are formed on both sides of the second clad layer 7. A contact layer 8 is formed on the second clad layer 7 and the current block layers 6. Between the second clad layer 7 and the contact layer 8, current breaking layers 10a, 10b are formed in the vicinity of the laser output side end surface 15 and the reflection side end surface 16, respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a CD-R / RW.
The present invention relates to a semiconductor laser device used for an optical disk device such as a drive and a DVD-RAM drive, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In an optical recording apparatus, the recording speed has been improved, and for example, as a CD-R drive, a so-called 16x recording speed has been put to practical use. In such an optical recording apparatus having a high recording speed, it is necessary to instantly start up a high-output laser beam.
There is a ridge type semiconductor laser using a compound semiconductor as a laser that satisfies such required characteristics.

A semiconductor laser is a light emitting device in which light generated by recombination of electrons and holes is reflected inward on both end faces of the element, thereby causing laser oscillation. A protective film made of alumina or the like is formed on both end faces of the semiconductor laser element, that is, the laser emission side end face and the reflection side end face to protect them.

[0004]

However, in the manufacturing process of the semiconductor laser device, since the end face of the device is oxidized before the formation of the protective film, a large number of non-radiation re-emissions are formed on the laser emission side end face and the reflection side end face. Bonding centers are formed. At the time of laser emission, a current is injected into the entire element length from the laser emission side end face to the reflection side end face. At this time, non-radiative recombination occurs at the laser emission side end face and the reflection side end face to generate heat. When the band gap becomes smaller due to heat generation, absorption of laser light increases, and the temperature rises. By repeating this, the so-called COD (Catastrophical Optical) in which the end face of the laser element is melted
Damage) occurs and the semiconductor laser element is destroyed.

COD occurs at a certain level (destructive light output) as the light output of the semiconductor laser is increased. Therefore, the light output when the semiconductor laser device is used must be set lower than the destructive light output. Therefore, an object of the present invention is to provide a semiconductor laser device and a method for manufacturing the same, which can achieve a high output by improving the destructive light output.

[0006]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 for achieving the above object is a lower clad layer, an active layer and an upper first clad layer which are sequentially laminated on a compound semiconductor substrate. A ridge-shaped upper second cladding layer provided on the upper first cladding layer, a current blocking layer provided on a side of the upper second cladding layer, and an upper second cladding layer provided on the upper second cladding layer. Of the contact layer and the upper second clad layer and the contact layer in the vicinity of at least one of the laser emission side end surface and the reflection side end surface which are both end surfaces of the element in the longitudinal direction of the upper second clad layer. A semiconductor laser device, comprising: a current blocking layer made of an insulator provided therebetween.

According to the present invention, no current flows in the vicinity of the end facet on the laser emission side and / or the end face on the reflection side due to the current blocking layer which is an insulator. Therefore, non-radiative recombination does not occur and the temperature of the end face does not rise. As a result, the destruction light output of the semiconductor laser device can be improved, so that a high-output semiconductor laser device can be realized. The current blocking layer may be provided both in the vicinity of the laser emission side end face and in the vicinity of the reflection side end face, or may be provided only on either one. Further, when the current blocking layer is provided both near the laser emission side end face and near the reflection side end face, the lengths of the respective current blocking layers in the direction along the length direction of the element may be the same or different. May be. Since heat generation due to non-radiative recombination usually occurs remarkably on the laser emission side end face, the length of the current blocking layer may be longer on the laser emission side end face than on the reflection side end face. The current blocking layer may be provided only on the end face side on the emission side.

Each part of the semiconductor laser device can have the composition described in claim 2. That is, the compound semiconductor substrate may be a GaAs compound semiconductor substrate, and the lower cladding layer may be an Al _x1 Ga _(1-x1) As layer. The active layer may be a single layer of Al _y1 Ga _(1-y1) As, Al _y11 Ga _{(1-y1 1)} As and Al.
Composite layer with _y12 Ga _(1-y12) As or Al _y1 Ga
_It may be a composite layer of _(1-y1) As and GaAs. The active layer is MQW (Multi Quantum Well)
When it is an active layer, the active layer has a composite composition as described above.

The upper first cladding layer is made of Al _x2 Ga.
It may be a _(1-x2) As layer, and the ridge-shaped upper second cladding layer may be an Al _x3 Ga _(1-x3) As layer. The current blocking layer may be a single layer composed of an Al _y2 Ga _(1-y2) As layer, a lower layer composed of Al _y3 Ga _(1-y3) As and the contact layer disposed on the compound semiconductor substrate side. It may be a composite layer which is disposed on the side and includes an upper layer made of GaAs. The contact layer may be a GaAs layer.

Further, each part of the semiconductor laser device is
The composition described in 3 can also be taken. Sanawa
The compound semiconductor substrate is a GaAs compound semiconductor substrate
The lower cladding layer may be In_x1(Ga_y1
Al_(1-y1))_(1-x1)It may be a P layer. The active layer is
In_x2Ga_(1-x2)It may be a single layer of P, In_x3Ga
_(1-x3)P and In_x4(Ga_y4Al_(1-y4))_(1-x4)Compound with P
Ply or In_x5(Ga_y5Al _(1-y5))_(1-x5)P and I
n_x6(Ga_y6Al_(1-y6))_(1-x6)A composite layer with P,
Good. The active layer is MQW (Multi Quantum)
  Well) active layer, the active layer is as described above.
It has a complex composition.

The upper first cladding layer is made of In _x7 (Ga _y7
Al _(1-y7) ) _(1-x7) P layer, and the ridge-shaped upper second clad layer is In _x8 (Ga _y8 Al _(1-y8) ).
_It may be a _{(1-x 8)} P layer. The current blocking layer is G
aAs, Ga _y9 Al _(1-y9) As, In _x10 (Ga _y10 Al
_(1-y10) ) _(1-x10) P or a single layer of In _x11 Al _(1-x11) P may be used, and Ga _y9 Al _(1-y9) As is _provided on the compound semiconductor substrate side. , In _x10 ( _Gay10 Al
_(1-y10) ) _(1-x10) P, or In _x11 Al _(1-x11) P, which is disposed on the lower layer and the contact layer side, and GaA
It may be a composite layer including an upper layer made of s. The contact layer may be a GaAs layer.

The invention according to claim 4 is the semiconductor laser device according to any one of claims 1 to 3, wherein the current blocking layer is made of silicon oxide, silicon nitride, or aluminum oxide. A current blocking layer made of silicon oxide, silicon nitride, or aluminum oxide can satisfactorily block current. According to a fifth aspect of the present invention, a step of sequentially laminating a lower clad layer, an active layer, an upper first clad layer, and an upper second clad layer on a compound semiconductor substrate, and an insulator on the upper second clad layer Forming a strip-shaped mask layer, shaping the upper second cladding layer into a ridge shape using the mask layer, and forming a current blocking layer on a side of the ridge-shaped upper second cladding layer. A step of selectively growing, a step of removing the mask layer except a portion near at least one end portion in the longitudinal direction of the mask layer, and an ohmic contact with the upper second clad layer on the upper second clad layer. And a step of forming a contact layer.

By this manufacturing method, the semiconductor laser device according to the first aspect can be obtained. The remaining part of the mask layer, which is removed except for the vicinity of at least one of the laser emission side end face and the reflection side end face, becomes the current blocking layer. The upper second cladding layer may be shaped into a ridge by etching using the mask layer as a mask. In that case, the top first
An etching stop layer having resistance to the etching medium may be provided between the clad layer and the upper second clad layer to protect a layer below the etching stop layer from etching.

The step of partially removing the mask layer as described above is performed by forming a resist on the upper surface of the remaining portion of the mask layer and removing the portion where the resist is not formed by wet etching. You can When the upper second clad layer is shaped into a ridge by etching, the lower portion in the vicinity of the end portion in the width direction of the mask layer is also removed. That is, the mask layer is in a state of protruding in the width direction of the ridge-shaped upper second cladding layer. Then, the upper second
It is possible to form a current blocking layer on both sides of the clad layer so that the lower side of the protruding mask layer is filled with the current blocking layer. When the mask layer is etched in this state, the mask layer is etched only from the upper surface.
Only the portion where the resist is not formed on the upper surface can be removed.

In the conventional method of manufacturing a ridge type semiconductor laser, the mask layer is entirely removed after the current blocking layer is formed on the side of the upper second cladding layer. In the manufacturing method of the present invention, a part of the mask layer is left as described above to form a current blocking layer. Therefore, a high-power semiconductor laser device including a current blocking layer can be obtained without significantly increasing the number of steps from the conventional manufacturing method. The invention according to claim 6 is the method for manufacturing a semiconductor laser device according to claim 5, wherein the mask layer is made of silicon oxide, silicon nitride, or aluminum oxide.

According to the present invention, the semiconductor laser device according to the third aspect can be obtained. MOCVD (Metal
-Organic Chemical VaporDe
When the AlGaAs semiconductor laser device is formed by the position method, the current blocking layer can be selectively grown on both sides of the upper second cladding layer by using the mask layer made of silicon oxide. That is, the material forming the current blocking layer is not deposited on the mask layer.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view along the length direction of the ridge type semiconductor laser device according to the first embodiment of the present invention, showing the structure thereof. FIG. 2 is a schematic sectional view of the ridge-type semiconductor laser device of FIG. 1 in a direction orthogonal to the length direction. Figure 2 (a)
2 is a sectional view taken along line IIa-IIa in FIG. 1, and FIG.
IIb-IIb line sectional view of FIG. FIG. 1 is shown in FIG.
It is the II sectional view taken on the line of (b).

One end face in the length direction of this ridge type semiconductor laser device is a laser emission side end face 15, and the other end face is a reflection side end face 16. Board 1
A lower clad layer 2, an active layer 3, an upper first clad layer 4 and an etching stop layer 5 are sequentially stacked on the above. A ridge-shaped upper second clad layer 7 is formed on the etching stop layer 5 along the length direction of the element and at a substantially central portion in the width direction of the element. The current blocking layers 6 are formed on both sides of the upper second cladding layer 7. The current blocking layer 6 is formed along the side surface of the upper second cladding layer 7 and the upper surface of the etching stop layer 5. On the upper second clad layer 7 and the current blocking layer 6, a contact layer 8 which is in ohmic contact with the upper second clad layer 7 is formed.

Between the upper second cladding layer 7 and the contact layer 8, current blocking layers 10a and 10b are formed near the laser emitting side end face 15 and near the reflecting side end face 16, respectively. The current blocking layers 10a and 10b are not formed on the inner portions of the laser emission side end face 15 and the reflection side end face 16 respectively by a predetermined distance or more. That is, the contact layer 8 is in contact with the upper part of the upper second cladding layer 7 at a portion inward of the laser emission side end face 15 and the reflection side end face 16 by a predetermined distance or more.

The substrate 1 is, for example, an n-type GaAs compound semiconductor substrate. In this case, the lower clad layer 2 is
It can be composed of an n-type Al _x1 Ga _(1-x1) As layer.
The active layer 3 has n-type, p-type, or undoped conductivity type, and may be an Al _y1 Ga _(1-y1) As layer or two layers having different compositions. That is, Al _y11 Ga _(1-y11) As and Al _y12 Ga _(1-y12) As
MQW consisting of (y11 ≠ y12) (Multi Q
Quantum Well) active layer, or A
It may be an MQW active layer made of l _y1 Ga _(1-y1) As and GaAs.

The upper first cladding layer 4 is a p-type Al _x2 Ga layer.
It can be composed of a _(1-x2) As layer. The etching stop layer 5 may be composed of a p-type In _(1-Z) Ga _Z P layer and have resistance to an etching medium. Further, the current blocking layer 6 is made of n-type Al _y2 Ga.
_(1-y2) As layer, the ridge-shaped upper second cladding layer 7 may be formed of p-type Al _x3 Ga _(1-x3) As layer, and the contact layer 8 may be formed of p-type Al _x3 Ga _(1-x3) As layer. Type GaAs layer. Current blocking layers 10a, 10b
Is made of silicon oxide (SiO ₂ ).

An n-side electrode 12 and a p-side electrode 13 are formed on the lower surface of the substrate 1 and the upper surface of the contact layer 8, respectively. The n-side electrode 12 and the p-side electrode 13 are formed over the entire length from the laser emission side end face 15 to the reflection side end face 16. N-side electrode 1 on the device during laser emission
A current is passed through 2 and the p-side electrode 13. Therefore, in these electrode portions, the current flows over the entire area in the length direction of the element. However, in the vicinity of the laser emission side end surface 15 and the reflection side end surface 16, the current blocking layer 10 is formed.
Since a and 10b are present, no current flows. Therefore, the laser emission side end face 15 and the reflection side end face 1
In No. 6, non-radiative recombination does not occur even if the non-radiative recombination center is present. That is, according to the ridge type semiconductor laser having such a configuration, heat generation of the semiconductor laser element can be suppressed, and thus the destructive light output can be remarkably improved.
This makes it possible to increase the output of the semiconductor laser device.

Current blocking layer 1 in the direction along the length of the device
The lengths of 0a and 10b (hereinafter referred to as "laser emission side non-injection width" and "reflection side non-injection width", respectively) can be set arbitrarily. Even if the non-injection width on the laser emission side or the non-injection width on the reflection side is excessively increased as compared with the size of the element, the effect of suppressing non-radiative recombination is not improved. On the other hand, when the non-injection width on the laser emission side or the non-injection width on the reflection side is increased, the length of the region into which the current is injected is substantially reduced, resulting in an increase in the drive current. The size of the non-injection width on the laser emission side and the non-injection width on the reflection side can be set to an optimum size in consideration of these things.

The current blocking layer 10 on the laser emitting side end face 15 side
Both the current blocking layer 10b on the side of a and the end face 16 on the reflection side may be provided, or only one of them may be provided. When both the current blocking layers 10a and 10b are provided, the laser emission side non-injection width and the reflection side non-injection width may be the same or different.
The heat generated by the non-radiative recombination is usually generated by the end facet 1 on the laser emission side.
5, the laser emission side non-injection width may be made longer than the reflection side non-injection width, and the current blocking layer 10a may be provided only in the vicinity of the laser emission side end face 15.

The current blocking layers 10a and 10b may be made of silicon nitride or aluminum oxide. Even in this case, the current can be satisfactorily cut off, and heat generation in the vicinity of the laser emission side end face 15 and the reflection side end face 16 can be suppressed. FIG. 3 is a schematic perspective view showing a method of manufacturing the ridge type semiconductor laser device of FIGS. 1 and 2 in the order of steps. On the substrate 1, a lower clad layer 2, an active layer 3, an upper first clad layer 4, an etching stop layer 5,
And the upper second cladding layer 7 are sequentially formed (see FIG. 3).
(A)). These steps are carried out by MOCVD (Metal-
Organic Chemical Vapor Dep
position) method.

After that, on the surface of the upper second cladding layer 7,
A band-shaped mask layer 11 made of SiO ₂ is formed. Such a mask layer 11 is formed of Si by a sputtering method.
It can be obtained by forming an O ₂ film on the entire surface of the upper second cladding layer and then shaping it into a band shape by a photoetching method. Next, using the mask layer 11 as a mask, the upper second cladding layer 7 is etched into a ridge shape. This allows
The upper second cladding layer 7 below the mask layer 11 is also partially removed. That is, the mask layer 11 is in a state of protruding in the width direction from the ridge-shaped upper second cladding layer 7. Since the etching stop layer 5 has resistance to the etching medium, the layers below the etching stop layer 5 are not etched. This state is shown in FIG.

Then, on both sides of the upper second cladding layer 7,
The current block layer 6 is formed by the MOCVD method (FIG. 3).
(C)). At this time, the current block layer 6 selectively grows on the side surface of the ridge-shaped upper second cladding layer 7 and on the etching stop layer 5. That is, the material forming the current blocking layer 6 is not deposited on the mask layer 11. Further, the lower portion of the protruding mask layer 11 is filled with the current block layer 6.

After that, the mask layer 11 is removed by etching, leaving the vicinity of both ends in the length direction of the mask layer 11. The rest of the mask layer 11 is the current blocking layers 10a and 10b.
Becomes This state is shown in FIG. This step can be performed using a photoetching method. That is, of the mask layer 11, a resist is formed on the upper surface of the portion to be left, the portion where the resist is not formed is removed by etching, and then the resist is removed to obtain the current blocking layers 10a and 10b. be able to.

Further, MO is formed on the current blocking layer 6, the upper second cladding layer 7 and the current blocking layers 10a and 10b.
The contact layer 8 made of p-type GaAs is formed by the CVD method (FIG. 3E). Finally, an n-side electrode and a p-side electrode (not shown) are formed on the lower surface of the substrate 1 and the upper surface of the contact layer 8 to complete the ridge type semiconductor laser device. The above description is based on one ridge type semiconductor laser device (chip) as a unit. However, film formation is performed in a state in which regions corresponding to a plurality of chips are closely arranged on one large substrate 1 and cleavage is performed. Can be cut into individual chips.

According to such a semiconductor laser device manufacturing method, the current blocking layers 10a and 10b are formed by using the mask layer 11 used in the conventional semiconductor laser manufacturing method.
Can be formed. That is, in the conventional manufacturing method, the mask layer 11 is completely removed after the current blocking layer 6 is formed, but according to the manufacturing method of the present invention, the mask layer 11 is partially removed and the remaining part is left. Current blocking layer 10
a and 10b. Therefore, with such a manufacturing method, a high-power semiconductor laser device having the current blocking layers 10a and 10b can be obtained without significantly increasing the number of steps as compared with the conventional manufacturing method.

According to the above-described manufacturing method, the step of partially removing the mask layer 11 (FIG. 3D) is performed after the lower portion of the protruding mask layer 11 is filled with the current block layer 6. When the mask layer 11 is etched in this state, the mask layer 11 is etched only from the upper surface, so that only the portion where the resist is not formed can be satisfactorily removed. The mask layer 11 may be made of silicon nitride or aluminum oxide. In this case, a semiconductor laser device having the current blocking layers 10a and 10b composed of silicon nitride or aluminum oxide, which can obtain a semiconductor laser device, is an example of AlGaAs system.
It may be InGaAlP type. That is, the substrate 1
Can be composed of a GaAs compound semiconductor substrate,
The lower clad layer 2 is made of In _x1 (Ga _y1 Al _(1-y1) ).
It can be composed of a _(1-x1) P layer. The active layer 3 is In
_x2 Ga _(1-x2) P single layer, In _x3 Ga _(1-x3) P and In
_x4 ( _{Gay4Al (1-y4)} ) _(1-x4) P composite layer, or I
_{n x5 (Ga y5 Al (1} -y5)) (1-x5) P and In _x6 (Ga _y6 A
l _(1-y6) ) _(1-x6) P and a composite layer.

The upper first cladding layer 4 is made of In _x7 (Ga _y7
Al _(1-y7) ) _(1-x7) P layer, and the second upper cladding layer 7 is composed of In _x8 (Ga _y8 Al _(1-y8) ) _(1-x8)
It can be composed of P layers. The current blocking layer 6 is G
aAs, Ga _y9 Al _(1-y9) As, In _x10 (Ga _y10 Al
_(1-y10) ) _(1-x10) P, or In _x11 Al _(1-x11) P. The contact layer 8 is
It can be composed of a GaAs layer.

FIG. 4 is a schematic sectional view in the direction orthogonal to the length direction of the ridge type semiconductor laser device according to the second embodiment of the present invention, showing the structure thereof. Figure 4 (a)
4 shows a cross section in the vicinity of the laser emission side end face 15, and FIG.
(B) has shown the cross section near the central part of the length direction of an element. Portions having the same configurations as those of the semiconductor laser device according to the embodiment shown in FIGS. The lower clad layer 22 and the active layer 2 are formed on the substrate 21.
3, the upper first cladding layer 24, and the etching stop layer 5 are sequentially stacked. Upper first cladding layer 24
An upper second clad layer 27 having a ridge shape is formed on the upper part of the element along the length direction of the element, and at a substantially central portion in the width direction of the element. The current blocking layers 26 are formed on both sides of the upper second cladding layer 27. Current blocking layer 26
Is formed along the side surface of the upper second clad layer 27 and the upper surface of the etching stop layer 5, and is arranged on the lower layer 26a disposed on the substrate 21 side and on the lower layer 26a (the side far from the substrate 21). And an upper layer 26b. A contact layer 28 that makes ohmic contact with the upper second cladding layer 27 is formed on the upper second cladding layer 27 and the current blocking layer 26.

Upper second cladding layer 27 and contact layer 2
8 and the vicinity of the laser emission side end face 15 (see FIG.
Current blocking layers 10a and 10b are formed in the vicinity of (a). The current blocking layers 10a and 10b are not formed on the inner portions of the laser emission side end face 15 and the reflection side end face 16 respectively by a predetermined distance or more. That is, the contact layer 28 is in contact with the upper part of the upper second cladding layer 27 at a portion inside the laser emitting side end face 15 and the reflecting side end face 16 by a predetermined distance or more.

The substrate 21 is, for example, an n-type GaAs compound.
It consists of a semiconductor substrate. In this case, the lower clad layer 22
Is n-type In_x1(Ga_y1Al_(1-y1))_(1-x1)Consists of P layer
can do. The active layer 23 has n-type conductivity and p-type.
Type or undoped, In_x2Ga_(1-x2)P layer
May consist of two layers of different composition
May be. That is, In_x5(Ga_y5Al_(1-y5))
_(1-x5)P and In_x6(Ga_y6Al_(1-y6))_(1-x6)P (y5
≠ y6) and MQW (Multi Quantu)
m Well) active layer, or In_x3Ga
_(1-x3)P and In_x4(Ga _y4Al_(1-y4))_(1-x4)From P
The MQW active layer may be

The upper first cladding layer 24 is a p-type In
It can be composed of a _x7 ( _{Gay7Al (1-y7)} ) _(1-x7) P layer. Further, the conductivity type of the current block layer 26 may be n-type, and the lower layer 26a may be made of Ga _y9 Al _(1-y9) A.
It may be an s-layer, or In _x10 (Ga _y10 A
l _(1-y10) ) _(1-x10) P layer, or In _x11 A
It may be an l _(1-x11) P layer. The upper layer 26b is Ga
It can be composed of an As layer. Ridge-shaped upper second
The clad layer 27 is made of p-type In _x8 (Ga _y8 Al _(1-y8) ).
_(1-x8) P layer, the contact layer 28
Can be composed of a p-type GaAs layer.

The current blocking layers 10a and 10b, even in the semiconductor laser device made of such InGaAsP-based material, have the same effect as in the semiconductor laser device made of the AlGaAs-based material (first embodiment). Can be played. The semiconductor laser of the second embodiment can also be obtained by the same manufacturing method as the semiconductor laser of the first embodiment. In this case, if the current block layer 26 made of a 3 (4) element mixed crystal such as AlGaAs is formed on both sides of the upper second cladding layer 27 shaped like a ridge by the MOCVD method, the mask layer 11 is not formed. The material forming the current blocking layer 26 is also deposited on the upper surface. Therefore, such a situation can be avoided by forming a thin layer of a ternary mixed crystal material as the lower layer 26a and then forming an upper layer 26b of GaAs. That is, with such a configuration, the current blocking layer 26 can be favorably selectively grown on both sides of the upper second cladding layer 27, and the current blocking layer 26 having a required thickness can be obtained.

As in the first embodiment of the present invention, also in the semiconductor laser device mainly made of AlGaAs material, the current blocking layer 6 is composed of the lower layer made of ternary mixed crystal and the upper layer made of GaAs. With the configuration, the above effects can be obtained. In addition, various changes can be made within the scope of the matters described in the claims.

[0039]

EXAMPLE FIG. 5 shows various samples of the semiconductor laser device having the structure shown in FIG. This is a summary of the results of measuring the current. In all samples, the non-injection width on the laser emission side and the non-injection width on the reflection side were set to the same value. The non-injection width on the horizontal axis of FIG. 5 is the laser emission side non-injection width (reflection side non-injection width).
And The drive current is a value at a temperature of 85 ° C. and a power of 100 mW.

The destructive light output increases with the increase of the non-injection width in the range of the non-injection width of 40 μm or less, but hardly changes when the non-injection width exceeds 40 μm.
When it exceeds μm, it starts to decrease. On the other hand, the drive current increases almost linearly as the non-injection width increases. More specifically, the increase rate of the drive current is smaller in the range where the non-injection width is smaller than 40 μm than in the range where the non-injection width is larger than 40 μm. From the above, for example, 4
A preferred non-injection width is 20-40 μm (eg, 30 μm) when aiming for a destructive light output of greater than 00 mW.

[Brief description of drawings]

FIG. 1 is a schematic sectional view along a length direction of a device showing a structure of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of the ridge type semiconductor laser device of FIG. 1 in a direction orthogonal to the length direction.

FIG. 3 is a schematic perspective view showing a method of manufacturing the ridge-type semiconductor laser device of FIGS. 1 and 2 in the order of steps.

FIG. 4 is a schematic sectional view in the direction orthogonal to the length direction of the ridge type semiconductor laser device according to the second embodiment of the present invention, showing the structure thereof.

FIG. 5 is a characteristic diagram showing the relationship between the non-injection width and the destructive light output and drive current.

[Explanation of symbols]

1,21 substrate 2,22 Lower clad layer 3,23 Active layer 4,24 Upper first cladding layer 5 Etching stop layer 6,26 Current blocking layer 26a lower layer 26b Upper layer 7,27 Upper second cladding layer 8,28 Contact layer 10a, 10b Current blocking layer 15 Laser emission side end face 16 Reflective end face

Continued front page    F-term (reference) 5F073 AA09 AA74 AA87 BA05 CA04                       CA05 CA14 CB02 DA05 EA24                       EA28

Claims (6)

[Claims] 1. A lower clad layer, an active layer, and an upper first clad layer, which are sequentially stacked on a compound semiconductor substrate, a ridge-shaped upper second clad layer provided on the upper first clad layer, and A current blocking layer provided on a side of the upper second clad layer, a contact layer provided on the upper second clad layer, and a laser emission side that is both end faces of the element in the longitudinal direction of the upper second clad layer. A semiconductor laser device comprising a current blocking layer made of an insulator provided between the upper second cladding layer and the contact layer in the vicinity of at least one of the end face and the reflection-side end face. 2. The compound semiconductor substrate is a GaAs compound semiconductor substrate, the lower cladding layer is an Al _x1 Ga _(1-x1) As layer, and the active layer is a single layer of Al _y1 Ga _(1-y1) As. Layer, Al _y11 G
a _(1-y11) As and Al _{y1 2} Ga _(1-y12) As composite layer,
Or a composite layer of Al _y1 Ga _(1-y1) As and GaAs, the upper first clad layer is an Al _x2 Ga _(1-x2) As layer, and the ridge-shaped upper second clad layer is Al. _x3 Ga
_(1-x3) As layer, wherein the current block layer is a single layer made of Al _y2 Ga _(1-y2) As, or Al _y3 G that is arranged on the compound semiconductor substrate side.
2. The semiconductor layer according to claim 1, wherein the contact layer is a GaAs layer, which is a composite layer including a lower layer made of a _(1-y3) As and an upper layer made of GaAs and arranged on the contact layer side. Laser device. 3. The compound semiconductor substrate is a GaAs compound semiconductor.
Is a conductor board, The lower clad layer is In_x1(Ga_y1Al_(1-y1))
_(1-x1)P layer, The active layer is In_x2Ga_(1-x2)P single layer, In_x3Ga
_(1-x3)P and In_x4(Ga _y4Al_(1-y4))_(1-x4)Compound with P
Ply or In_x5(Ga_y5Al_(1-y5))_(1-x5)P and I
n_x6(Ga_y6Al_(1-y6))_(1-x6)Is a composite layer with P, The upper first cladding layer is In_x7(Ga_y7Al_(1-y7))
_(1-x7)P layer, The ridge-shaped upper second cladding layer is In_x8(Ga_y8
Al_(1-y8))_(1-x8)P layer, The current blocking layer is GaAs, Ga_y9Al_(1-y9)A
s, In_x10(Ga_y10Al_(1-y10))_(1-x10)P
Is In_x11Al_(1-x11)A single layer composed of P, or the above compound
Ga is arranged on the semiconductor substrate side._y9Al_(1-y9)As, In
_x10(Ga_y10Al_{(1 -y10)})_(1-x10)P or In
_x11Al_(1-x11)Lower layer made of P and the contact
It is a composite layer that is arranged on the layer side and includes an upper layer made of GaAs.
, The contact layer is a GaAs layer
The semiconductor laser device according to claim 1. 4. The semiconductor laser device according to claim 1, wherein the current blocking layer is made of silicon oxide, silicon nitride, or aluminum oxide. 5. A step of sequentially laminating a lower clad layer, an active layer, an upper first clad layer, and an upper second clad layer on a compound semiconductor substrate, and a strip-shaped strip made of an insulator on the upper second clad layer. Forming a mask layer, shaping the upper second cladding layer into a ridge shape using the mask layer, and selectively growing a current blocking layer on a side of the ridge-shaped upper second cladding layer. A step of removing the mask layer, leaving at least one end portion vicinity in the longitudinal direction of the mask layer, and a contact layer in ohmic contact with the upper second clad layer on the upper second clad layer. And a step of forming the semiconductor laser. 6. The method for manufacturing a semiconductor laser device according to claim 5, wherein the mask layer is made of silicon oxide, silicon nitride, or aluminum oxide.