JP2908125B2 - Semiconductor laser device and method of manufacturing the same - Google Patents

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 having a stripe structure having a current confinement mechanism by a pn junction and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the practical use of semiconductor laser devices having the advantages of small size, high output, and low cost, the application of lasers to general industrial equipment and consumer equipment, for which use of laser light sources has been difficult in the past, has been advanced. I have. Above all, optical communication, optical measurement,
BACKGROUND ART There has been remarkable progress in fields such as optical-related devices such as optical disk devices. In the future, semiconductor laser devices are expected to be applied to more fields.

As an example, FIG. 7 shows a conventional semiconductor laser device having a typical stripe structure. This semiconductor laser device is called an index guided stripe laser,
n-type AlG sequentially formed on an n-type GaAs substrate 71
aAs first cladding layer 72, AlGaAs active layer 73,
a p-type AlGaAs second cladding layer 74, an n-type GaAs current confinement layer 77, a p-type AlGaAs third cladding layer 78,
And a p-type GaAs contact layer 79. An n-type electrode 717 is provided on the back surface of the substrate 71, and a p-type electrode 718 is provided on the surface of the contact layer 79.
Is provided.

In the current confinement layer 77, a stripe groove 712 is provided.
Is formed, and the inside of the groove is filled with a third cladding layer 78. That is, the third cladding layer 78 is in contact with the second cladding layer 74 at the bottom of the stripe groove. Further, the current confinement layer 77 is made of a semiconductor material having a smaller forbidden band width than the active layer 73. Therefore, in the active layer 73, an equivalent refractive index difference occurs in a direction parallel to the bonding surface, the equivalent refractive index increases below the stripe groove, and light generated in the active layer is indicated by a hatched portion in FIG. As shown, it is confined in the light emitting region. In this way, fundamental transverse mode resonance is obtained.

Further, in the peripheral portion of the stripe groove, the second
Since the cladding layer 74, the current confinement layer 77, and the third cladding layer 78 have a pnp structure, the injected current is also confined in the stripe groove as shown by the arrow in FIG.

[0006]

However, in the above-described conventional semiconductor laser device having a single stripe structure, the current flowing through the third cladding layer 74 is smaller than the size of the light emitting region shown by hatching in FIG. The spread is large and the ratio of the injected carriers to laser oscillation is low. This is because, as shown in FIG. 7, the current spread is large relative to the width of the optical waveguide, and the threshold current increases due to the presence of injected carriers that do not contribute to laser oscillation. In fact, in a conventional semiconductor laser device having a double hetero (DH) structure capable of oscillating in the 780 nm band, the threshold current was 40 mA. Of these, 20 mA or more is considered to be a leakage current that does not contribute to laser oscillation.

As described above, in the conventional single-stripe semiconductor laser device, the current confinement layer 77 also functions as a current blocking layer, and the injected current is confined in the stripe groove 712. Compared with this, the current spread is large, and the ratio of the leakage current that does not contribute to laser oscillation (considered to be more than half) increases. As a result, the threshold current increases, so that the drive current increases,
In particular, it had a significant effect on reliability and noise characteristics.

The present invention solves the above-mentioned conventional problems. A first object of the present invention is to provide an efficient refractive index waveguide structure having a reduced leakage current and a threshold current. It is an object of the present invention to provide a semiconductor laser device which is low and has particularly excellent reliability and noise characteristics.

A second object of the present invention is to provide a method for suitably manufacturing the above-mentioned semiconductor laser device.

[0010]

According to the present invention, there is provided a semiconductor laser device comprising an active layer made of Al _y Ga _{1 -y} As (where y is from 0 to 1).
The _{first and second} sides in the up-down direction are made of Al _x Ga _1-x As.
Cladding layer (x is 0 or more and 1 or less) and the Al _z Ga _1-z second cladding layer made of As (z is 0 or more and 1 or less) and the laminated portion of the de sandwiched therebetween comprising a light generation, two spaced apart stripe groove for current constriction between the current blocking layer is formed, a third cladding layer made of Al _w Ga _1-w As on of the current blocking layer comprising said striped grooves (w is 0 or more and 1 or less) A current blocking mechanism provided on a GaAs substrate, and a conductivity type of a portion of the third cladding layer above the bottom of the stripe groove and a conductivity type of a portion above both side surfaces of the stripe groove. This achieves the first object.

A method for manufacturing a semiconductor laser device according to the present invention comprises:
Active layer made of Al _y Ga _1-y As (y is 0 or more and 1 or less)
A first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As and a second cladding layer (z is 0 or more and 1 or less) made of Al _z Ga _{1 -z} As A stripe for current confinement is formed between the stacked light-generating layer sandwiched between the two current blocking layers and the current blocking layer, and Al _w Ga _1-w is formed on the current blocking layer including the stripe groove. A method of manufacturing a semiconductor laser device having a current confinement mechanism provided with a third cladding layer made of As (w is 0 or more and 1 or less) on a GaAs substrate, wherein the light-generating laminated portion is formed. The step and the plane orientation of the bottom of the stripe groove are (111) A and the plane directions of both side surfaces thereof are (100), and an amphoteric impurity is doped on the current blocking layer including the stripe groove. Laminating a third cladding layer, whereby the third cladding layer Forming the current confinement mechanism portion in which the conductivity type of the portion above the bottom of the stripe groove and the conductivity type of the portions above both side surfaces of the stripe groove are different from each other. Objective is achieved.

Another semiconductor laser device of the present invention is:
Active layer made of Al _y Ga _1-y As (y is 0 or more and 1 or less)
A first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As and a second cladding layer (z is 0 or more and 1 or less) made of Al _z Ga _{1 -z} As A light-generating laminated portion sandwiched between the first clad layer and the second clad layer;
Two separated current blocking layers and a GaAs substrate are provided in this order on one side of the cladding layer, and a current constriction stripe groove reaching the bottom of the substrate is formed between the current blocking layers. The inside of the stripe groove is filled with the one cladding layer, and the conductivity type of a portion above the bottom of the stripe groove in the one cladding layer is different from the conductivity type of a portion above both side surfaces of the stripe groove. Thus, the first object is achieved.

According to another method of manufacturing a semiconductor laser device of the present invention, both sides in the vertical direction of an active layer made of Al _y Ga _{1 -y} As (y is 0 or more and 1 or less) are made of Al _x Ga _{1 -x} As. First clad layer (x is 0 or more and 1 or less) and Al _z Ga _{1 -z} A
a second cladding layer made of s (z is 0 or more and 1 or less), and has a light-generating laminated portion, which is separated from one of the first cladding layer and the second cladding layer. Two current blocking layers and a GaAs substrate are provided in this order, a stripe groove for current confinement reaching the bottom of the substrate is formed between the current blocking layers, and the one cladding layer is formed inside the stripe groove. A method of manufacturing a buried semiconductor laser device, wherein the plane orientation of the bottom of the stripe groove is (111) A and the plane directions of both side surfaces thereof are (100), and the plane direction is (100) on the current blocking layer including the stripe groove. The one clad layer is laminated, whereby the conductivity type of a portion above the bottom of the stripe groove in the one clad layer is different from the conductivity type of a portion above both side surfaces of the stripe groove. And forming the Forming a lamination portion for generating,
And thereby the second object is achieved.

[0014]

In another method of manufacturing a semiconductor laser device according to the present invention, both sides in the vertical direction of an active layer made of Al _y Ga _{1 -y} As (y is 0 or more and 1 or less) are made of Al _x Ga _{1 -x} As. the first cladding layer (x is 0 or more and 1 or less) and a second cladding layer made of Al _z Ga _1-z as with a ridge portion for current confinement (z is 0 or more and 1 or less) and de sandwiched therebetween comprising a photogenerating And a third cladding layer (w is 0 or more and 1 or less) made of Al _w Ga _{1 -w} As on the second cladding layer including at least both side surfaces of the ridge portion on the GaAs substrate. A method of manufacturing a semiconductor laser device, comprising: setting the plane orientation of both side surfaces of the ridge portion to (100) and the plane orientation of the second cladding layer portions on both sides sandwiching the ridge portion to (111) A; Formed on the second cladding layer by doping with an amphoteric impurity A third cladding layer is laminated so that the conductivity type of the ridge portion is different from the conductivity type of portions of the third cladding layer above both side surfaces of the ridge portion, thereby achieving the second object. Achieved.

[0016]

According to the semiconductor laser device of the present invention, in the third cladding layer formed on the current confining stripe groove, the conductivity type of the portion above the bottom of the stripe groove and the conductivity type of both sides of the stripe groove are determined. Since the upper portion has a different conductivity type, the current can be confined with a width smaller than the width of the bottom of the stripe groove sandwiched between the current blocking layers.

In another semiconductor laser device, the conductivity type of the ridge portion for current confinement is different from the conductivity type of portions of the third cladding layer above both side surfaces of the ridge portion. Since it is formed, the current can be confined with a width smaller than the width of the bottom of the ridge portion sandwiched between the current blocking layers. Therefore, in any of these semiconductor laser devices, the injection current is efficiently confined to the light emitting region with a narrower stripe width in the light emitting region limited by the current blocking layer.

Therefore, compared with the conventional semiconductor laser device having a single stripe structure, the leakage current in the horizontal direction is reduced, and the threshold current is greatly reduced. As a result, the reliability is significantly improved. In particular, since both end portions of the light emitting region in the direction parallel to the active layer function as a saturable absorber with a decrease in injection current, self-sustained pulsation is very easy to occur, and noise characteristics are significantly improved.

In the production method of the present invention, (100)
Has a surface and (111) A plane, on a layer having a stripe groove or ridge for current confinement, a third cladding layer amphoteric impurities consisting Al _w Ga _1-w As doped is stacked You. The amphoteric impurity acts as an acceptor or a donor due to the difference in plane orientation, so that the layers stacked on the (100) plane and the (111) A plane have different conductivity types due to the difference in plane orientation.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 (a) to 1 (e) are views showing the steps of manufacturing a semiconductor laser device according to Embodiment 1 of the present invention. First, as shown in FIG.
Al is formed on the (111) A surface of the substrate 1 by using a usual method.
_x Ga _1-x As first cladding layer 2, Al _y Ga _{1 -y} As active layer 3, a p-type Al _z Ga _1-z As lamination portion for light emission comprising a second cladding layer 4 is formed, further , And p-type Ga
As first protective layer 5, n-type Al _s Ga _{1 -s} As etching stop layer 6 (s is 0 or more and 1 or less), n-type GaAs
The current blocking layers 7 are sequentially formed. The above is produced in the first growth step.

Next, as shown in FIG. 1B, a stripe-shaped photoresist pattern 11 is formed on the epitaxial wafer obtained by the photolithography technique.
Form one. Then, the photoresist pattern 11
1 is used as an etching mask, the current blocking layer 7 is etched using a GaAs selective etching solution until it reaches the surface of the etching stop 6. As a result, the current blocking layer 77 is separated, and a stripe groove 112 is formed therebetween. Both side surfaces 113 of this stripe groove 112 are made to be symmetric (100) planes. The bottom surface 114 of the stripe groove 112 becomes the (111) A plane.

Subsequently, as shown in FIG.
The etching stop layer 6 is removed by using an As selective etching solution, and the photoresist pattern 111 is further removed.

After the etching stop layer 6 is removed, a p-type Al _w Ga _{1 -w} As is formed on the current blocking layer 7 including the stripe groove 112 in a second growth step by MBE (Molecular Beam Epitaxy). Third cladding layer 8 (w is 0
(1 or less). Stripe groove 112
The current blocking layer 7 and the third cladding layer 8 form a current confinement mechanism.

The third cladding layer 8 is doped with an amphoteric impurity such as Si. As a result, the third
In the cladding layer 8, it is indicated by oblique lines in the figure (100).
Side surfaces 113, 113 of the stripe groove 112
The conductivity type of the side surfaces 116 and 116 of the groove stacked on top is n
And a central portion 115 formed on the (111) A plane.
And outer portions 152, 15 of the side portions 116, 116
The conductivity type of No. 2 is p-type. The amphoteric impurity acts as an acceptor or a donor due to the difference in the plane orientation of the surface on which the third cladding layer 8 is laminated.
6, 116 and the central portion 115 have opposite conductivity types. This phenomenon is reported, for example, in Appl. Phys. Lett., 47 (12), 1309 (1985). According to this report, (100)
Temperature on a GaAs substrate with a (111) A plane
GaAs doped with Si at 610 ° C. and V / III = 25
Is grown, it shows n-type conductivity on the (100) plane, but shows p-type conductivity on the (111) A plane.

Actually, a Si-doped Al _0.50 G is deposited on a GaAs substrate having a step between the (100) plane and the (111) A plane.
The case where a _0.50 As is grown using the MBE method will be described. FIG. 2 shows the relationship between the substrate temperature during growth and the pressure of As with respect to the conductivity on the (111) plane. As shown in FIG. 2, at a substrate temperature of 400 ° C. to 800 ° C., the lower the As pressure, the more likely it is to become p-type, and at 700 ° C. or higher, it becomes p-type under most conditions. On the (100) plane, it was n-type under all conditions. When Si enters the As position and acts as an acceptor to form a p-type semiconductor,
As adsorbed on the (111) A surface is G
a, its adhesion coefficient is small, and impurities S
Since i is likely to enter the As position by Ga bonding, the above AlGaAs is likely to be p-type. Increasing the substrate temperature or lowering the As pressure lowers the adhesion coefficient of As, so that the substrate tends to be p-type.

In this embodiment, the third cladding layer was grown at a substrate temperature of 720 ° C. and an As pressure of 4 × 10 ^-4 Torr using Si as an amphoteric impurity.

Next, p-type GaAs is formed on the third cladding layer 8.
An s-contact layer 9 is formed, and an n-type electrode 117 is formed on the substrate 1 side, and a p-type electrode 118 is formed on the contact layer 9 side.

In the first embodiment, the width w of the stripe groove 112 is
₁ was 4 μm. In this embodiment, the composition and thickness of each semiconductor layer laminated on the substrate 1 are formed, for example, as follows.

First cladding layer 2: n-type Al _x Ga _{1 -x} A
s, x = 0.50, thickness 1.5 μm, active layer 3: Al _y Ga _1-y A
s, y = 0.13, thickness 500 Å, second cladding layer 4: p-type Al _z Ga ₁ -z As, z = 0.50, thickness 0.3 μm
m, first protective layer 5: p-type GaAs, thickness 50 Å, etching stop layer 6: p-type Al _s Ga _{1 -s} A
s, s = 0.50, thickness 100 Å, current blocking layer 7: n-type GaAs, thickness 0.7 μm, third cladding layer 8: p
Type Al _w Ga _{1 -w} As, w = 0.50, thickness 0.5 μm, contact layer 9: p-type GaAs, thickness 1 μm.

Since the protective layer 5 is made of GaAs, its thickness is preferably 100 Å or less so that its light absorption effect does not hinder the waveguide structure. In the first embodiment, the thickness of the protective layer 5 is about 50 angstroms, which is sufficiently thin, and has almost no light absorption effect and does not hinder the waveguide structure.

In the semiconductor laser device of this embodiment, the light emitting region is confined by the current blocking layer 7 having a smaller forbidden band width than the active layer 3, while the injected current is supplied to both sides 116 of the narrower stripe groove. Confined by
Therefore, as shown by the arrow in FIG. 1E, most of the injected current is injected into the light emitting region indicated by the region a, and the leakage current in the parallel direction is smaller than that of the conventional semiconductor laser device having the stripe structure. Significantly reduced.

Actually, when the semiconductor laser device of the above embodiment employing the DH structure capable of oscillating in the 780 nm band was manufactured,
The threshold current was 25 mA. This is a drastic reduction as compared with the conventional single-stripe semiconductor laser device threshold current of 40 mA. Further, when the active layer 3 has a multiple quantum well structure and employs an SCH structure, the threshold current is further increased.
Reduced to 10mA.

Further, a decrease in the leakage current in the horizontal direction leads to a decrease in the drive current, and the reliability particularly under high output has been improved. When the semiconductor laser device of the above example was operated under the conditions of 50 ° C. and 70 mW, the reliability was about 5,000 hours. This is the reliability value (2,000 yen) when a conventional single-stripe semiconductor laser device is operated under the same conditions.
Time).

Further, in the semiconductor laser device of the above embodiment, as shown in FIG. 1E, both ends in the direction parallel to the active layer 3 in the light-emitting region indicated by oblique lines have a small injection current and a saturable absorption. Since it functions as a body, self-sustained pulsation is very easy to occur, and noise characteristics are remarkably superior to those of a conventional semiconductor laser device having a single stripe structure.

(Embodiment 2) A semiconductor laser device shown in FIG. 3 has an n-type GaAs substrate 31 on which an n-type Al _x Ga _{1 -x}
As first cladding layer 32, Al _y Ga _1-y As active layer 3
3, p-type Al _z Ga _{1 -z} As second cladding layer 34, p-type G
aAs first protective layer 35, n-type Al _s Ga _1-s As etching stop layer 36, n-type Al _u Ga _1-u As current blocking layer 3
7 (u is 0 or more and less).

In the second embodiment, the current blocking layer 37 is made of A
nGaAs, and n is formed on the current blocking layer 37.
A type GaAs protective layer 310 is formed. In the present embodiment, since the current blocking layer 37 is formed of AlGaAs, the protective layer 38 is necessary when the later-described Al _w Ga _{1 -w} As third cladding layer 39 is grown by MBE. .

The current blocking layer 37 has a stripe groove 312 formed in the same manner as in the first embodiment.
The side surfaces 313 and 313 of (2) are (100) planes, and the bottom surface 314 is a (111) A plane. n-type GaAs protective layer 31
A third cladding layer 38 and a contact layer 39 are formed on the layer 0 by the MBE method as in the first embodiment. The electrodes 317 and 318 are the same as in the first embodiment.

In this embodiment, the structure other than the current blocking layer 37 and the second protective layer 310 is the same as that of the first embodiment, and only the both sides 316 in the stripe groove of the third cladding layer 38 are n-type conductive. And others showed p-type conductivity.

The current blocking layer 37 is formed of n-type Al _u Ga _1-u As, the mixed crystal ratio u is 0.20 and the thickness is 1 μm, and the second protective layer 310 is formed of p-type GaAs. Was set to 0.1 μm. In addition, it is of course good to set the mixed crystal ratio u to 0.50.

In the semiconductor laser device of this embodiment,
Since the forbidden band width of the current blocking layer 37 is larger than that of the active layer 33, a real refractive index waveguide without light absorption is obtained, and the threshold current is further reduced.

Embodiment 3 The present invention is also applicable to a semiconductor laser device having a current confinement mechanism formed on the substrate side. An example is shown in FIG.

This semiconductor laser device has an n-type GaAs current blocking layer 4 on the (111) A surface of a p-type GaAs substrate 41.
2 are laminated, and a stripe groove 412 is formed in the current blocking layer 42 by etching. The side surfaces 413 and 413 of the stripe groove 412 are (100) planes, and the bottom surface 414 is a (111) A plane. in addition,
The Al _w Ga _{1 -w} As second cladding layer 43 is grown by MBE to form a current confinement mechanism. In the present embodiment, the second cladding layer also functions as the third cladding layer in the first and second embodiments.

On this structure, an Al _y Ga _{1 -y} As active layer 44, an n-type Al _z Ga _{1 -z} As first cladding layer 45,
An aAs contact layer 46 is formed. Further, the p-type electrode 418 is provided on the substrate 41 side, and the n-type electrode 418 is provided on the contact layer 46 side.
A mold electrode 417 is formed.

The materials constituting the respective semiconductor layers formed on the substrate 61 of the fifth embodiment can be the same as the corresponding portions in the first embodiment.

In this structure, since both sides 416 of the stripe groove of the third cladding layer exhibit n-type conductivity, the active layer 4
The side portions 416 can be formed up to an area close to 4.
Further, the current can be confined. The active layer 4
Since 4 has a step, a real refractive index waveguide is formed at this portion.

(Embodiment 4) Another example of a semiconductor laser device having a current confinement mechanism formed on the substrate side is shown in FIG.

This semiconductor laser device has an n-type GaAs current blocking layer 5 on the (111) A surface of a p-type GaAs substrate 51.
2 are laminated, and a stripe groove 512 is formed in the current blocking layer 52 by etching. The side surfaces 513 and 513 of the stripe groove 512 are (100) planes, and the bottom surface 514 is a (111) A plane. in addition,
Al _w Ga _{1 -w} As third cladding layer 53 and p-type GaAs
The first protective layer 54 is grown by the MBE method to form a current confinement mechanism.

On this structure, the p-type Al _x Ga _{1 -x} As first cladding layer 5 is formed by an LPE (liquid phase epitaxy) method.
5, Al _y Ga _1-y As active layer 56, n-type Al _z Ga _1-z A
An s second cladding layer 57 and a GaAs contact layer 58 are formed. Further, a p-type electrode 518 is provided on the substrate 51 side.
An n-type electrode 517 is formed on the contact layer 58 side.

The materials constituting the respective semiconductor layers formed on the substrate 51 of the fourth embodiment can be the same as the corresponding portions in the first embodiment.

In the semiconductor laser device of this embodiment, the light emitting region has the current blocking layer 52 having a smaller forbidden band width than the active layer 56.
Whereas the injected current is confined by the sides 516 inside the narrower stripe groove. Therefore, the leakage current in the parallel direction is significantly reduced as compared with a conventional semiconductor laser device having a stripe structure.

(Embodiment 5) The laser device shown in FIG. 6 has an n-type Al _x Ga _{1 -x} A on an n-type GaAs substrate 61.
The p-type A on which the s first cladding layer 62, the Al _y Ga _1-y As active layer 63 and the stripe-shaped ridge portion 620 are formed.
a light-generating laminated portion composed of the l _z Ga _{1 -z} As second cladding layer 64, a GaAs protection layer 65, and a GaAs current blocking layer 6;
7 are laminated. In this embodiment, the second
Striped ridge 6 formed on cladding layer 64
At 20, current constriction occurs. Second cladding layer 64
On the top, except for the upper part of the ridge portion 620, Al _w
A Ga _{1 -w} As third cladding layer 68 and a contact layer 69 are formed. An n-type electrode 617 is formed on the substrate 71 side, and a p-type electrode 618 is formed on the contact layer 610 side.

This semiconductor laser device can be manufactured as follows. First, (100) of the substrate 61
The protective layer 6 is formed on the surface in the first growth step by a normal method.
5, and a dielectric film (not shown) made of, for example, Al ₂ O ₃ is formed on the protective layer 65 in a stripe shape. Using this stripe as a mask, the second cladding layer 64 is used.
Then, etching is performed so that the plane orientation of the side surfaces 613 and 613 becomes (100) to form a ridge portion 620. The second cladding layer 64 includes p-type GaAs as indicated by a broken line in the figure.
When the ridge portion 620 is formed by etching, the etching stop layer 66 made of is provided.

After the formation of the ridge portion 620, the third cladding layer 6
8 and the current blocking layer 67 are formed in the second growth step by the MBE method. The plane orientation of the ridge side faces 613, 613 is (100), and the plane orientation of the second cladding layer portions 614, 614 sandwiching the ridge is (111) A.

In the present embodiment, as in the first embodiment, the third
By doping the cladding layer 68 with an amphoteric impurity such as Si, the conductivity type of the side portion 616 and the conductivity type of the portion 615 can be different. As a result, the current confinement width can be further reduced as in the first embodiment.

In each embodiment, the first clad layer and the second clad layer constituting the laminated structure only need to have a composition such that the forbidden band width is larger than that of the active layer. The composition may have changed. further,
As a structure defining an optical waveguide, not only a DH (double heterostructure) structure in which an active layer is sandwiched between a pair of clad layers, but also, for example, an SCH (separated) in which an optical guide layer is inserted between the active layer and the clad layer. confiment heterost
(Ructure) structure and a GRIN-SCH structure in which a GRIN (graded index) layer is inserted. Further, the active layer may have a multiple quantum well structure.

[0057]

According to the present invention, a semiconductor laser device having an efficient refractive index waveguide structure with reduced leakage current and oscillating in a stable fundamental transverse mode can be obtained. This semiconductor laser device has a low threshold current and is particularly excellent in reliability and noise characteristics. Further, according to the manufacturing method of the present invention, a semiconductor laser device having excellent oscillation characteristics can be manufactured with a high yield in only two crystal growth steps and at most three crystal growth steps.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a manufacturing process of a semiconductor laser device of Example 1 of the present invention.

FIG. 2 is a diagram illustrating conductivity on a (111) A plane of a GaAs substrate.

FIG. 3 is a longitudinal sectional view of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a semiconductor laser device according to a third embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a semiconductor laser device according to a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a semiconductor laser device according to a fifth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a conventional semiconductor laser device.

[Explanation of symbols]

1, 31, 41, 51, 61, 71 Substrate 2, 32, 45, 55, 62, 72 First cladding layer 3, 33, 44, 56, 63, 73 Active layer 4, 34, 43, 57, 64, 74 Second cladding layer 8, 38, 53, 68, 78 Third cladding layer 7, 37, 42, 52, 67 Electron blocking layer 112, 312, 412, 512, 612, 712 Stripe groove 113, 313, 413, 513 , 613 stripe groove side surface 114, 214, 314, 414, 514 stripe groove bottom surface 115, 215, 315, 415, 515, 615 central portion 116, 216, 316, 416, 516, 616 side surface portion 620 ridge portion

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinji Kaneiwa 22-22, Nagaikecho, Abeno-ku, Osaka, Osaka Inside Sharp Corporation (72) Inventor Masafumi Kondo 22-22, Nagaikecho, Abeno-ku, Osaka, Osaka Incorporated (72) Inventor Toshio Hata 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-1-239980 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/18

Claims (5)

(57) [Claims] An active layer made of Al _y Ga _{1 -y} As (y is 0
The first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As is provided on both sides in the vertical direction of the above (1 or less) and Al _z Ga _{1 -z}
A stacked layer for light generation sandwiched by a second cladding layer made of As (z is 0 or more and 1 or less) and a stripe groove for current confinement are formed between two current blocking layers separated from each other. Al _w Ga _{1 -w} A is formed on the current blocking layer including the stripe groove.
and a current confinement mechanism provided with a third cladding layer made of s (w is 0 or more and 1 or less) on a GaAs substrate.
A semiconductor laser device in which the conductivity type of a portion above the bottom of the stripe groove in the cladding layer is different from the conductivity type of portions above both side surfaces of the stripe groove. 2. An active layer made of Al _y Ga _1-y As (where y is 0).
The first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As is provided on both sides in the vertical direction of the above (1 or less) and Al _z Ga _{1 -z}
A stacked layer for light generation sandwiched by a second cladding layer made of As (z is 0 or more and 1 or less) and a stripe groove for current confinement are formed between two current blocking layers separated from each other. Al _w Ga _{1 -w} A is formed on the current blocking layer including the stripe groove.
and a current confinement mechanism provided with a third cladding layer made of s (w is 0 or more and 1 or less) on a GaAs substrate, wherein the light-generating laminated portion is formed. A step of forming (111) A the plane orientation at the bottom of the stripe groove and (100) at both sides thereof, and doping an amphoteric impurity on the current blocking layer including the stripe groove. A current confining mechanism in which a third clad layer is laminated, whereby the conductivity type of the portion above the bottom of the stripe groove in the third clad layer is different from the conductivity type of the portions above both side surfaces of the stripe groove. And a step of forming a portion. 3. An active layer made of Al _y Ga _1-y As (where y is 0).
The first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As is provided on both sides in the vertical direction of the above (1 or less) and Al _z Ga _{1 -z}
A light-generating laminated portion sandwiched between a second cladding layer made of As (z is 0 or more and 1 or less), and is separated from one of the first cladding layer and the second cladding layer; Two current blocking layers and a GaAs substrate are provided in this order, a stripe groove for current confinement reaching the bottom of the substrate is formed between the current blocking layers, and the one cladding layer is formed inside the stripe groove. A semiconductor laser device in which the conductivity type of a portion above the bottom of the stripe groove in the one of the buried cladding layers is different from the conductivity type of portions above both side surfaces of the stripe groove. 4. An active layer made of Al _y Ga _1-y As (where y is 0).
1 inclusive) first cladding layer in the vertical direction on both sides made of Al _x Ga _1-x As of (x is 0 or more and 1 or less) and AlGa _1-z
As second cladding layer made of _z (z is 0 or more and 1 or less) and de sandwiched therebetween has a laminated portion for light generation comprising, for one-way of the first clad layer or second clad layer, spaced apart 2
A current blocking layer and a GaAs substrate are provided in this order, a current confining stripe groove reaching the bottom of the substrate is formed between the current blocking layers, and the inside of the stripe groove is formed in the stripe groove.
A method of manufacturing a semiconductor laser device in which one of the cladding layers is embedded, wherein the plane orientation at the bottom of the stripe groove is (111) A and the plane directions at both sides thereof are (100), and the current including the stripe groove is Laminating the one cladding layer on the blocking layer,
A step of forming the conductive type of the portion above the bottom of the stripe groove in the one clad layer different from the conductive type of the portion above both side surfaces of the stripe groove; Forming a laminated portion of the above, and a method of manufacturing a semiconductor laser device. 5. An active layer made of Al _y Ga _1-y As (where y is 0).
The first cladding layer (x is 0 or more and 1 or less) made of Al _x Ga _{1 -x} As and the second cladding layer made of Al _z Ga _{1 -z} As having a ridge portion for current confinement are formed on both sides in the vertical direction (above 1). A light-generating laminated portion sandwiched between clad layers (z is 0 or more and 1 or less), and a second layer made of Al _w Ga _{1 -w} As on the second clad layer including at least both side surfaces of the ridge portion. A method of manufacturing a semiconductor laser device having three cladding layers (w is 0 or more and 1 or less) on a GaAs substrate, wherein a plane orientation of both side surfaces of the ridge portion is (100) and both sides sandwiching the ridge portion are provided. The plane orientation of the second cladding layer portion is set to (11
1) A is formed, and then a third cladding layer formed by doping an amphoteric impurity on the second cladding layer is laminated, and the conductivity type of the ridge portion and the ridge portion of the third cladding layer are formed. A method of manufacturing a semiconductor laser device, wherein the conductivity types of portions above both side surfaces are different.