JP3160138B2 - Semiconductor laser device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refractive index guided semiconductor laser device having an internal current confinement structure, and to manufacture this semiconductor laser device by one growth using MBE (Molecular Beam Epitaxy). It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, semiconductor laser devices have been actively developed for use as light sources for optical information processing. Semiconductor laser devices for this purpose are required to have performances such as small astigmatism, a narrow radiation spread angle, and oscillation in a single mode. As a semiconductor laser device having such performance, a refractive index guided semiconductor laser device having an internal current confinement structure has been developed. The manufacture of a refractive index guided semiconductor laser device having this internal current confinement structure requires at least two or more crystal growth steps. However, in consideration of the yield and the manufacturing cost, the semiconductor laser can be manufactured in one crystal growth step. It is desirable that the device can be manufactured.

[0003] The applicant of the present application has disclosed, for example, Japanese Patent Application No.
In 291805, by one crystal growth step,
A method of manufacturing a refractive index guided semiconductor laser device having an internal current confinement structure has been proposed.

This manufacturing method utilizes the fact that the conductivity type of the Si-doped GaAs semiconductor layer and the Si-doped AlGaAs layer depends on the plane orientation when the semiconductor layer is grown. Hereinafter, a manufacturing process of a semiconductor laser device according to this manufacturing method will be described with reference to FIGS.

[0005] First, as shown in FIG.
A resist 91 is formed on the surface of the aAs substrate 91 in the plane orientation (100).
0 is formed.

Next, as shown in FIG. 19B, a stripe 915 is formed on the resist 910 on the substrate 91 by using a photolithography technique.

Subsequently, as shown in FIG. 19C, a V-groove is formed in the stripe 915 portion of the substrate 91 by etching using the resist 910 having the stripe 915 formed thereon as a mask. A mixed solution of phosphoric acid and aqueous hydrogen peroxide was used as an etchant. A mixed solution of sulfuric acid and aqueous hydrogen peroxide may be used. The cross-sectional shape of the V-groove was such that the plane orientation of both inclined surfaces 920 was (111) A, and the groove width was 3 μm.

Next, as shown in FIG. 19D, a side surface 920 having a plane orientation of (111) A and a plane orientation of (411) are used as a etchant using a mixed solution of sulfuric acid and a hydrogen peroxide solution as an etchant.
A V-groove including the side surface 921 as the A surface is formed. When the formation of the V groove is completed, as shown in FIG. 19E, the resist 910 is removed, and the substrate 91 is treated with concentrated sulfuric acid.

Subsequently, on such a substrate 91, FIG.
As shown in (f), the Si-doped GaAs current confinement layer 9
2 is grown, and on this current confinement layer 92, FIG.
9 (g), the p-type AlGaAs cladding layer 9
3. A GaAs active layer 94, an n-type AlGaAs cladding layer 95 and an n-type GaAs contact layer 96 are sequentially grown by MBE.

[0010] Finally, the p-side electrode 912 is placed on the substrate 91 side.
An n-side electrode 913 is formed on the contact layer 96 side to obtain the semiconductor laser device of the first embodiment.

In the MBE (Molecular Beam Epitaxy) method, GaAs doped with Si (silicon) as an n-type dopant is used to convert the GaAs to (n11) A (1 ≦ n ≦
It is known that when grown on a surface which is 3), the adhesion of As is suppressed in the growth process, and the semiconductor layer is inverted to p-type. On the other hand, if the plane orientation is (n11) A (n ≧ 4) or (10
On the plane of 0), such a phenomenon is not observed, and the growth layer becomes n-type.

Therefore, in the above-described conventional semiconductor laser device, the plane orientation is (111) as shown in FIG.
A plane 920 which is A and a plane 92 whose plane orientation is (411) A
1 and a V-groove having side surfaces composed of two surfaces, and a Si-doped GaAs on a substrate 91 having a surface orientation of (100).
When the layer 92 is grown, only the Si-doped GaAs layer (shaded portion) on the surface 920 of the V-groove shows p-type conductivity,
The growth layer on the surface 921 of the groove and on the surface 922 having the (100) plane orientation shows n-type conductivity. Thus, a semiconductor laser device having an internal current confinement structure can be manufactured.

In the above-mentioned semiconductor laser device, the central portion 930 of the active layer 94 is surrounded by the AlGaAs cladding layers 93 and 95 having a large energy gap and a small refractive index, and constitutes a real refractive index waveguide structure. Transverse mode oscillation can be obtained.

As described above, when a semiconductor laser device is fabricated by processing a groove formed of a plurality of planes on a substrate and combining the MBE method with the substrate, a refraction having an internal current confinement structure can be obtained by one crystal growth. An index guided semiconductor laser device can be realized.

[0015]

However, in the above-described semiconductor laser device, the central portion 930 of the active layer 94 serving as a light emitting portion has a plane orientation of (n11) A (1 ≦).
n having a surface 920 satisfying n ≦ 3) as both side surfaces.
Since it is formed immediately above the groove, it is slightly bent to the substrate 91 side, and the layer thickness at this portion tends to be increased. For this reason, the effective refractive index of the central portion 930 of the active layer 94 is increased, and the laser light is guided while converging on the central portion, so that there is a problem that the horizontal transverse mode becomes higher-order oscillation.

Further, since a current spreading in the lateral direction flows in the p-type and n-type cladding layers, there is a problem that the driving current is increased.

Further, in the manufacture of the semiconductor laser device, when a semiconductor layer is grown on a plane having a plane orientation of (n11) A (1 ≦ n ≦ 3), a plane having a plane orientation of (100). There is also a problem that the crystallinity is poor as compared with the above growth and light loss occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a semiconductor laser device having an internal current confinement structure which suppresses a laterally spreading current and has a high light extraction efficiency and a method of manufacturing the same. The purpose is to provide.

[0019]

According to a semiconductor laser device of the present invention, at least an active layer comprising a first semiconductor layer is provided.
A semiconductor including a light-emitting laminated portion sandwiched between a second semiconductor layer having a larger bandgap than the first semiconductor layer and a third semiconductor layer having a larger bandgap than the first semiconductor layer; In the laser device, a groove having a bottom surface and both side surfaces is formed on the surface of a p-type GaAs substrate having a surface having a surface orientation of (100), and the surface orientation of the bottom surface is (100).
And each side face has a different plane orientation in the depth direction of the groove.
On a substrate formed as one or more surfaces, a Si-doped current confinement layer shows p-type conductivity on at least one or more of the side surfaces, and a p-type conductivity other than the one or more surfaces. Above, it is formed so as to exhibit n-type conductivity, and the light emitting laminated portion is formed on the current confinement layer, thereby achieving the above object.

Further , the semiconductor laser device of the present invention
At least the active layer made of the first semiconductor layer is
A second semiconductor layer having a larger forbidden band width than the conductor layer;
With the third semiconductor layer having a larger forbidden band width than the semiconductor layer of
A semiconductor laser device having a light emitting laminated portion sandwiched between
There are, the light emitting laminate portion at least Si-doped AlG
a part or the whole area in the layer thickness direction in a region of the cladding layer that includes an aAs cladding layer and that corresponds to at least one or more of the side surfaces of the groove exhibits p-type conductivity; A region of the clad layer corresponding to the other surface of the side surface and the surface of the substrate connected to the edge of the groove has a configuration exhibiting n-type conductivity.

Further , the semiconductor laser device of the present invention has a small
At least the active layer made of the first semiconductor layer is
A second semiconductor layer having a larger forbidden band width than the conductor layer;
With the third semiconductor layer having a larger forbidden band width than the semiconductor layer of
A semiconductor laser device having a light emitting laminated portion sandwiched between
A Si-doped GaAs contact layer is formed on the light-emitting laminated portion, and a portion in a layer thickness direction of a region of the contact layer corresponding to at least one or more of side surfaces of the groove; Alternatively, the entire region shows p-type conductivity, and the region of the contact layer corresponding to the other surface of the side surface of the groove and the surface of the substrate connected to the edge of the groove has n-type conductivity. ing.

In one embodiment, the Si-doped current confinement layer comprises at least a GaAs layer.

In one embodiment, the Si-doped current confinement layer comprises at least an AlGaAs layer.
The forbidden band width of the s layer is smaller than the forbidden band width of the first semiconductor layer.

In one embodiment, the Si-doped current confinement layer is made of an AlGaAs layer, and the forbidden band width of the AlGaAs layer is larger than at least the forbidden band width of the first semiconductor layer. It is the same as or smaller than the forbidden band width of the semiconductor layer and the third semiconductor layer.

In one embodiment, the Si-doped current confinement layer comprises at least a GaAs layer and an AlGaAs layer, the bandgap of the AlGaAs layer is larger than the bandgap of the first semiconductor layer, and The forbidden band width of the second semiconductor layer and the third semiconductor layer is the same as or smaller than the forbidden band width.

In one embodiment, the Si-doped current confinement layer comprises at least a first AlGaAs layer and a second AlG layer.
the first AlGaAs layer has a forbidden band width smaller than the forbidden band width of the first semiconductor layer, and the forbidden band width of the second AlGaAs layer is smaller than the forbidden band width of the second AlGaAs layer. 3 is equal to or smaller than the forbidden band width of the semiconductor layer.

In one embodiment, the Si-doped current confinement layer comprises at least GaAs, a first AlGaAs layer and a second AlGaAs layer, and the first AlGaAs
The forbidden band width of the s layer is larger than the forbidden band widths of the second semiconductor layer and the third semiconductor layer, and the second AlGaAs
4. The semiconductor laser device according to claim 1, wherein the forbidden band width of the s layer is equal to or smaller than the forbidden band widths of the second semiconductor layer and the third semiconductor layer.

In one embodiment, the Si-doped current confinement layer comprises at least GaAs and an AlGaAs layer, and the bandgap of the AlGaAs layer is the bandgap of the second semiconductor layer and the third semiconductor layer. Greater than.

In one embodiment, the Si-doped current confinement layer includes at least a first AlGaAs layer and a second AlGaAs layer.
A first GaAs layer and a third AlGaAs layer;
The bandgap of the AlGaAs layer is smaller than the bandgap of the first semiconductor layer, and the bandgap of the second AlGaAs layer is smaller than the bandgap of the second semiconductor layer and the third semiconductor layer. And the forbidden band width of the third AlGaAs layer is equal to or smaller than the forbidden band widths of the second semiconductor layer and the third semiconductor layer.

According to the method of manufacturing a semiconductor laser device of the present invention, at least the upper and lower surfaces of the active layer comprising the first semiconductor layer are formed by forming a second semiconductor layer having a larger forbidden band width than the first semiconductor layer; In a method for manufacturing a semiconductor laser device including a light emitting laminated portion sandwiched between a third semiconductor layer having a larger forbidden band width than the first semiconductor layer, the plane orientation is (100).
By etching the surface of a p-type GaAs substrate having the surface as described above with at least two or more types of etchants, a groove having a bottom surface and both side surfaces is formed so that the bottom surface has a plane orientation of (100). A) forming each side surface as two or more surfaces having different plane orientations in the groove depth direction; and forming a Si-doped current confinement layer on the substrate on which the groove is formed. Forming p-type conductivity on at least one or more surfaces thereof, and n-type conductivity on surfaces other than the one or more surfaces; Forming the light emitting layered portion thereon, thereby achieving the above object.

In one embodiment, the light emitting laminated portion includes at least a Si-doped AlGaAs cladding layer, and a thickness direction in a region of the cladding layer corresponding to at least one of the side surfaces of the groove. Part or all of the region shows p-type conductivity, and the region of the cladding layer corresponding to the other surface of the side surface of the groove and the surface of the substrate connected to the edge of the groove shows n-type conductivity. Formed.

In one embodiment, the method includes a step of forming a Si-doped GaAs contact layer on the light emitting laminated portion, and a part or the entire region of the contact layer in the thickness direction is a p-type conductive layer. And a region of the contact layer corresponding to the other surface of the side surface of the groove and the surface of the substrate connected to the edge of the groove is formed so as to exhibit n-type conductivity.

[0033]

According to the semiconductor laser device of the present invention, a groove having a bottom surface and both side surfaces is formed on the surface of a p-type GaAs substrate whose surface is oriented at (100).
The plane orientation of the bottom of the groove is the same as the plane orientation of the substrate surface (10
0), and each side surface of the groove is formed by two or more surfaces having different plane orientations in the depth direction of the groove.

A Si-doped current confinement layer is formed on the substrate, and a region corresponding to at least one of the side surfaces of the groove of the current confinement layer exhibits p-type conductivity, The corresponding region on the other surface can exhibit n-type conductivity. Therefore, the current injection width can be limited to the p-type region of the current confinement layer.

Further, on the current confinement layer, a light-emitting laminated portion including a Si-doped AlGaAs cladding layer is formed, and this cladding layer is partially or entirely in the thickness direction of the current confinement layer. A region corresponding to the mold region shows p-type conductivity, and a region on the other surface shows n-type conductivity.

Further, a Si-doped GaAs contact layer is formed on the light emitting laminated portion. In this contact layer, the p-type conductive layer of the cladding layer is partially or entirely formed in the thickness direction. The region corresponding to the region exhibiting the conductivity exhibits p-type conductivity, and the region on the other surface exhibits n-type conductivity.

The current path is further narrowed by the p-type regions in the cladding layer and the contact layer.

The central portion of the active layer serving as the light emitting portion is surrounded by an AlGaAs cladding layer having a large energy gap and a small refractive index, and has a real refractive index waveguide structure. Since the central portion of the active layer is formed corresponding to the bottom of the groove, it is flat and has good crystallinity.

The grooves can be formed by performing etching using two or more kinds of etching liquids on the surface of a p-type GaAs substrate having a plane of (100) plane.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, parts having similar functions are denoted by the same reference numerals.

Example 1 FIG. 1F shows a cross section of a semiconductor laser device of Example 1. This semiconductor laser device
Two surfaces 100 and 101 having different plane orientations in the depth direction are provided on the surface of the p-type GaAs substrate 1 whose plane orientation is (100).
A groove having a side surface is provided. Of the two side surfaces 100 and 101 of the groove, the plane orientation of the side surface 100 is (11
1) A, and the plane orientation of the side surface 101 is (411) A. This groove has a bottom surface and its plane orientation is (100).

By filling this groove, on the substrate 1
A Si-doped GaAs current confinement layer 2 is formed. The current confinement layer 2 exhibits p-type conductivity in a region on the side surface 100 of the groove, and shows n-type conductivity in a region on the side surface 101, the bottom surface 102, and the outer surface 103 of the groove. .

On the Si-doped current confinement layer 2, a p-type A
l _x Ga ₁ -x As cladding layer 3 (for example, X = 0.5
0), the Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.1
4), n-type Al _W Ga _1-W As cladding layer 5 (for example, W
= 0.50) and an n-type GaAs contact layer 6 are laminated in this order. The cladding layers 3 and 5 are formed of a material having a larger band gap than the active layer 4.
The cladding layer 3, the active layer 4 and the cladding layer 5 constitute a light emitting laminate.

A p-side electrode 12 is formed on the p-type substrate 1 side, and an n-side electrode 13 is formed on the n-type contact layer 6 side. Such a semiconductor laser device is manufactured as follows.

First, as shown in FIG.
A resist 11 is applied on the surface of the As substrate 1.

Next, as shown in FIG. 1B, the resist 11 of the substrate 1 is
A stripe 15 having a width of 3 μm is formed.

Subsequently, as shown in FIG. 1C, two kinds of etching liquids, for example, two kinds of mixed liquids of sulfuric acid and hydrogen peroxide are used at the position where the stripes 15 are formed on the substrate 1. The plane orientation of the bottom surface is (100), and each side surface forms a V-groove composed of two plane orientations (111) A and (411) A. When the formation of the groove is completed, as shown in FIG. 1D, the resist 11 is removed, and the substrate 1 is treated with hot sulfuric acid.

Next, as shown in FIG. 1E, a Si-doped GaAs current confinement layer 2 having a thickness of 2 μm is grown in the MBE apparatus. As described above, in the MBE method, when GaAs doped with Si as an n-type dopant is grown on a plane having a plane orientation of (n11) A (1 ≦ n ≦ 3), As adheres during the growth process. Since the conductivity is suppressed, the conductivity of the semiconductor layer is inverted to p-type. On the other hand, the plane orientation is (n11)
Such a reversal phenomenon is not observed on the surface where A (n ≧ 4) or the surface where (100), and the conductivity of the Si-doped current confinement layer 2 on this surface becomes n-type. Such a phenomenon is not observed when another dopant is used.

FIG. 18 shows that the plane orientation of the GaAs substrate is (n1).
1) The dependence of the conductivity of the Si-doped GaAs layer on the substrate temperature and the pressure of As when the Si-doped GaAs layer is grown on the plane of A (1 ≦ n ≦ 3) is shown. In the example shown in this figure, the temperature condition of the substrate is 400 ° C. to 800 ° C.
Until between. As understood from the figure, the lower the pressure of As or the higher the substrate temperature, the more easily the conductivity of the Si-doped GaAs layer shows p-type, and almost shows the p-type at 700 ° C. or higher. The reason may be as follows.

That is, the plane orientation is (n11) A (1 ≦ n ≦
The surface 3) is covered with Ga having one bond and the adsorbed As has a small adhesion coefficient.
i is easily bonded to Ga to enter the As position. Further, when the substrate temperature is increased or the As pressure is decreased, the adhesion coefficient of As is further reduced, so that p-type is easily exhibited.

In FIG. 1E, the plane orientation is (111).
The current confinement layer 2 (shaded portion) on the side surface 100 of the groove A indicates p-type conductivity. On the other hand, the current constriction layers 111, 112, and 113 on the side surface 101 of the groove having the plane orientation (411) A, on the bottom surface 102 of the groove, and on the outside 103 of the groove show n-type. Therefore, in this semiconductor laser device, on the side surface 100 having the plane orientation of (111) A (the hatched portion 110)
Only the current path.

The ease of release of As adsorbed on Ga having one bond depends on the growth conditions of the Si-doped GaAs layer. When the temperature of the substrate 1 is relatively low,
In the growth under the condition that the s flux amount is large, As is hard to be liberated, and when covered with Ga having one bond, the plane orientation is a region on the plane of (111) A or (311) A. The region may also exhibit n-type conductivity. Therefore,
It is necessary to select appropriate growth conditions. Further, the two or more surfaces having different plane orientations in the groove depth direction are formed by Si-doped GaAs formed on at least one or more surfaces.
Any combination may be used as long as the s layer exhibits p-type conductivity, for example, a combination of the (111) A plane and the (311) A plane, or a combination of the (755) A plane and the (755) A plane. 511) It may be a combination with the A side, and 3
A combination of planes having two or more plane orientations may be used.

After the growth of the Si-doped GaAs current confinement layer 2, the p-type Al _x Ga _{1 -x}
As clad layer 3, Al _Y Ga _1-Y As active layer 4, n-type A
The 1 _W Ga _{1 -W} As clad layer 5 and the n-type GaAs contact layer 6 are sequentially grown.

As a dopant for the n-type cladding layer 5 and the n-type contact layer 6, an n-type dopant such as Sn may be used.
By increasing the amount of the flux, it can be grown so as to exhibit n-type conductivity.

Finally, a p-side electrode 12 is formed on the substrate 1 side, and an n-side electrode 13 is formed on the contact layer 6 side, to obtain a semiconductor laser device as shown in FIG.

In this semiconductor laser device, the central portion 112 of the active layer corresponding to the region where the groove is formed serves as a light emitting portion. This light emitting portion is surrounded by the AlGaAs cladding layers 3 and 5 having a large energy gap and a small refractive index, and has a real refractive index waveguide structure. Further, since the current path is narrowed to the width of the hatched portion shown in FIG.
The threshold current can be greatly reduced as compared with the conventional semiconductor laser device. Further, a bottom surface having the same plane orientation (100) as the surface of the substrate 1 is provided in the groove, and the central portion 112 of the active layer corresponds to the bottom surface of the groove. It is not thick, has excellent crystallinity, and easily obtains a fundamental transverse mode oscillation.

The semiconductor laser device of the first embodiment is
When fabricated as an m-band DH (double hetero) structure, the threshold current was 10 mA.

(Embodiment 2) FIG. 2 shows a semiconductor laser device of Embodiment 2. The semiconductor laser device according to the second embodiment uses Si
Except for the configuration of the doped current confinement layer 7, the configuration is the same as that of the first embodiment. The layers other than the Si-doped current confinement layer 7 are described with the same reference numerals as those of the first embodiment. The Si-doped current confinement layer 7 of this semiconductor laser device has a smaller band gap than the Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.14).
i of doped Al _Z Ga _1-Z As (e.g. Z = 0.10). Groove area with (111) A plane orientation (shaded area)
The upper Si-doped current confinement layer 7 exhibits p-type conductivity, and has a plane orientation of (100) on a side surface having a plane orientation of (411) A.
The Si-doped current confinement layer 7 in the region on the bottom surface of the groove and on the (100) outside both sides of the groove shows n-type conductivity.

In the semiconductor laser device of the second embodiment, since the current confinement layer 7 is made of AlGaAs, light emitted from the active layer 4 is smaller than that of the semiconductor laser device of the first embodiment.
Can be suppressed. Therefore, since the p-type Ga _x Al ₁ -x As clad layer 3 can be formed thin to reduce the horizontal spreading current, the threshold current can be further reduced.

(Embodiment 3) FIG. 3 shows a semiconductor laser device of Embodiment 3. A Si-doped Al _P Ga _1-P As clad layer (for example, P = 0.50) 8 and a p-type Al _P Ga _1-P are formed on a substrate 1 having the same configuration as the substrate of the semiconductor laser device of the first embodiment.
As cladding layer 3 (for example, P = 0.50), Al _Y Ga
_1-Y As active layer 4 (for example, Y = 0.14) and n-type A
1 _W Ga _{1 -W} As clad layer 5 (for example, W = 0.50)
Are formed in this order, and the Si-doped cladding layer 8 is
It functions as an i-doped current confinement layer. The forbidden band width of the Si-doped cladding layer 8 is larger than that of the active layer 4, and
The p-type cladding layer 3 and the n-type cladding layer 5 are the same or smaller.

In this Si-doped cladding layer 8, a portion formed on a groove region (shaded portion) having a plane orientation of (111) A shows p-type conductivity and a plane orientation of (411) A.
The portions formed on the region of the groove A, on the bottom surface of the groove whose plane orientation is (100), and on the (100) planes on both outer sides of the groove show n-type conductivity. Other structures can be the same as those in the first embodiment.

In the semiconductor laser device of the third embodiment, a Si-doped Al _P Ga _{1 -P} As clad layer 8 having a small refractive index and a large energy gap is used instead of a current confinement layer having a large refractive index (for example, a GaAs layer). , The current confinement is performed, so that a real refractive index waveguide structure without light absorption by the substrate 1 or the current confinement layer having a large refractive index can be obtained. Therefore, the p-type cladding layer 3 can be formed thin, so that the spread current in the horizontal direction can be reduced. Therefore, the light extraction efficiency can be improved, and the threshold current can be reduced.

(Embodiment 4) FIG. 4 shows a semiconductor laser device of Embodiment 4. The semiconductor laser device according to the fourth embodiment includes a Si-doped GaAs current confinement layer 2 and a Si-doped Al _P on a substrate 1 having the same configuration as the substrate of the semiconductor laser device according to the first embodiment.
Ga _1-P As clad layer 8 (for example, P = 0.50), p
Type cladding layer Al _x Ga ₁ -x As cladding layer 3 (for example, X
= 0.5), Al _Y Ga _1-Y As active layer 4 (for example, Y =
0.14) and n-type Al _W Ga _1-W As cladding layer 5
(For example, W = 0.5) are laminated in this order,
Other structures are the same as those of the semiconductor laser device of the first embodiment. Both the Si-doped current confinement layer 2 and the Si-doped cladding layer 8 serve as a current confinement layer. The Si-doped cladding layer 8 has a larger bandgap than the active layer 4 and has the same or smaller bandgap as the p-type cladding layer 3 and the n-type cladding layer 5.

The Si-doped current confinement layer 2 and Si
In the doped clad layer 8, a portion formed on a region (hatched portion) of a groove having a plane orientation of (111) A indicates p-type conductivity, and a portion formed on a region of a groove having a plane orientation of (411) A. ,
Portions formed on the bottom surface having the plane orientation of (100) and on the plane having the plane orientation of (100) on both outer sides of the groove show n-type conductivity. Other structures can be the same as those in the first embodiment.

The semiconductor laser device of the fourth embodiment has the
Since the current is confined not only in the i-doped current confinement layer 2 but also in the Si-doped cladding layer 8, even if the p-type cladding layer 3 is formed thin, the actual refractive index without light absorption by the substrate 1 or the current confinement layer A waveguide structure can be formed. Therefore, the spreading current in the horizontal direction is suppressed, and the threshold current can be further reduced.

(Embodiment 5) FIG. 5 shows a semiconductor laser device of Embodiment 5. The semiconductor laser device of the fifth embodiment, Si-doped on the substrate 1 having the same structure as the substrate of the semiconductor laser device of Example 1 Al _Z Ga _1-Z As the current confinement layer 7 (for example, Z
= 0.10), Si-doped Al _P Ga _1-P As clad layer 8 (for example, P = 0.50), p-type Al _X Ga _1-X As clad layer 3 (for example, X = 0.5), Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.14) and n-type Al _W Ga
_{A 1-W} As clad layer 5 (for example, W = 0.5) is laminated in this order, and the other structure is the same as that of the semiconductor laser device of the first embodiment.

In this semiconductor laser device, both the Si-doped current confinement layer 7 and the Si-doped cladding layer 8 serve as a current confinement layer. Si-doped current confinement layer 7
Denotes an Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.14)
The forbidden band width is smaller than that of the
The forbidden band width of the type cladding layer 3 and the n-type cladding layer 5 is the same or smaller.

The Si-doped current confinement layer 7 and the Si
In the doped clad layer 8, a portion formed on a region (hatched portion) of a groove having a plane orientation of (111) A indicates p-type conductivity, and a portion formed on a region of a groove having a plane orientation of (411) A. ,
Portions formed on the bottom surface having the plane orientation of (100) and on the plane having the plane orientation of (100) on both outer sides of the groove show n-type conductivity. Other structures can be the same as those in the first embodiment.

[0069] The semiconductor laser device of the fifth embodiment, the current confinement layer is made of Si-doped Al _Z Ga _1-Z As the current confinement layer 7, even when formed thin p-type cladding layer 3, Example 4
As compared with the semiconductor laser device described above, a real refractive index waveguide structure with less light absorption by the substrate and the current confinement layer can be obtained. Therefore, the spreading current in the horizontal direction is suppressed, and the threshold current can be further reduced.

(Embodiment 6) FIG. 6 shows a semiconductor laser device of Embodiment 6. In the semiconductor laser device of the sixth embodiment, a Si-doped GaAs current confinement layer 2 as a current confinement layer and a Si-doped Al _Q Ga _1-Q As are formed on a substrate 1 having the same configuration as the substrate of the semiconductor laser device of the first embodiment. Optical confinement layer 9 (for example, Q = 0.60), Si-doped Al _P Ga _{1 -P} As cladding layer 8 (for example, P = 0.5), p-type Al _X Ga _{1 -X} As
Cladding layer 3 (for example, X = 0.5), Al _Y Ga _1-Y As
Active layer 4 (for example, Y = 0.14) and n-type Al _W Ga
_1-W As clad layers 5 (for example, W = 0.5) are laminated in this order. The Si-doped light confinement layer 9 has a larger band gap than the p-type cladding layer 3 and the n-type cladding layer 5. Other structures are the same as those of the semiconductor laser device of the first embodiment.

In the Si-doped current confinement layer 2, the Si-doped light confinement layer 9 and the Si-doped cladding layer 8, the portions formed on the groove regions (shaded portions) having the plane orientation of (111) A are p-type. And the plane orientation is (4
11) The portion formed on the region of the groove of A, on the bottom surface of the groove with the plane orientation of (100), and on the plane with the plane orientation of (100) on both outer sides of the groove shows n-type conductivity. Other structures can be the same as those in the first embodiment.

In the semiconductor laser device of the sixth embodiment, since the light confinement layer 9 has a smaller refractive index and a larger energy gap than the cladding layer 8, the light confinement layer 9 is extremely excellent without light absorption by the substrate 1 and the current confinement layer. A waveguide structure having an actual refractive index is obtained. Therefore, the current spreading in the horizontal direction is suppressed, and the light extraction efficiency is improved, so that the threshold current can be further reduced.

(Embodiment 7) FIG. 7 shows a semiconductor laser device of Embodiment 7. The semiconductor laser device of the seventh embodiment, on the semiconductor laser substrate 1 having the same structure as the substrate of the device of Example 1, Si-doped Al _Z Ga _1-Z As the current confinement layer 7 (e.g. Z = 0.10), Si-doped Al _Q Ga _1-Q As light confinement layer 9 (for example, Q = 0.60), Si-doped Al _P Ga
_1-P As clad layer 8 (for example, P = 0.5), p-type Al _x
Ga _1-x As clad layer 3 (for example, X = 0.5), Al _Y
A Ga _{1 -Y} As active layer 4 (for example, Y = 0.14) and an n-type Al _W Ga _{1 -W} As clad layer 5 (for example, W = 0.5) are stacked in this order. Si-doped current confinement layer 7
Has a smaller forbidden bandwidth than the active layer 4, and the Si-doped light confinement layer 9 has a larger forbidden bandwidth than the p-type cladding layer 3 and the n-type cladding layer 5. The Si-doped cladding layer 8 has the same or smaller band gap as the p-type cladding layer 3 and the n-type cladding layer 5. Other structures are the same as those of the semiconductor laser device of the first embodiment.

In the Si-doped current confinement layer 7, the Si-doped light confinement layer 9 and the Si-doped cladding layer 8, the portions formed on the groove regions (shaded portions) having the plane orientation of (111) A are p-type. And the plane orientation is (4
11) The portion formed on the region of the groove of A, on the bottom surface of the groove with the plane orientation of (100), and on the plane with the plane orientation of (100) on both outer sides of the groove shows n-type conductivity.

Since the Si-doped light confinement layer 9 has a smaller refractive index and a larger energy gap than the Si-doped cladding layer 8, a real refractive index waveguide structure in which light absorption by the substrate 1 and the current confinement layer is suppressed is provided. it can.

Further, since the current confinement layer 7 is formed of AlGaAs, a stronger real refractive index waveguide structure is obtained as compared with the semiconductor laser device of the sixth embodiment.

Therefore, the spread current in the horizontal direction is suppressed, and the threshold current can be significantly reduced.

(Eighth Embodiment) FIG. 8 shows a semiconductor laser device of the eighth embodiment. The semiconductor laser device of the eighth embodiment has the same basic structure as the semiconductor laser device of the first embodiment.
The difference is that the active layer 4 made of a _Y Al _1-Y As (for example, Y = 0.14) has a quantum well structure. An optical guide layer (not shown) made of Ga _Q Al _{1 -Q} As (for example, Q = 0.35) is provided between the active layer 4 and the clad layers 3 and 5, and the SCH (SeparateConfinement) is provided.
t Heterostructure) or GRIN
(Grade Refractive Index) -S
Since it has a CH structure, light can be sufficiently confined in the active layer 4. Since the active layer 4 has a quantum well structure,
Further, the threshold current can be reduced.

Further, in the Si-doped current confinement layer 2,
The region (shaded area) on the side surface of the groove having the plane orientation of (111) A indicates p-type conductivity, and the region of the groove having the plane direction of (100) on the side surface having the plane direction of (411) A. Regions on the bottom surface and on the plane with a plane orientation (100) on both outer sides of the groove show n-type conductivity. Other structures can be the same as those in the first embodiment.

The semiconductor laser device of the eighth embodiment has a threshold current of 1 mA, which is 1/10 that of the first embodiment.

In the semiconductor laser device of the eighth embodiment, the Si-doped GaAs layer 2 is formed as the current confinement layer.
Even if a current confinement layer similar to that of Examples 2 to 7 is formed, a very strong real refractive index waveguide structure without light absorption by the substrate or the current confinement layer can be obtained.

(Embodiment 9) FIG. 9 shows a semiconductor laser device of Embodiment 9. The semiconductor laser device of the ninth embodiment has
The present invention is applied to an InGaAlP-based red semiconductor laser device of a 60 nm band.

In this semiconductor laser device, a groove similar to that of the first embodiment is formed on the (100) plane of a p-type GaAs substrate 1, and a Si-doped GaAs current confinement layer 2 is formed on the substrate 1. In the Si-doped current confinement layer 2, a portion formed on a groove region (shaded portion) having a plane orientation of (111) A shows p-type conductivity and a plane orientation of (4).
11) The region formed on the region of the groove of A, on the bottom surface of the groove with the plane orientation of (100) and on the (100) plane on both outer sides of the groove shows n-type conductivity.

On the Si-doped current confinement layer 2, a p-type (Al _S Ga _{1 -S} ) _T In _{1 -T} P clad layer 3 (for example, S =
0.70, T = 0.51), (Al _M Ga _1-M ) _N In _1-N P
Active layer 4 (for example, M = 0, N = 0.51), n-type (A
l _U Ga _1-U ) _V In _1-V P cladding layer 5 (U = 0.70,
V = 0.51) and an n-type GaAs contact layer 6 are laminated in this order. The cladding layers 3 and 5
The cladding layer 3, the active layer 4, and the cladding layer 5 are formed of a material having a larger band gap than the active layer 4.

In this semiconductor laser device, the flat part of the active layer 4 becomes the light emitting part. This light emitting portion has a cladding layer 3 having a large energy gap and a small refractive index,
5 to form a real refractive index waveguide structure. Further, since the current path is narrowed to the width of the hatched portion, the threshold current can be greatly reduced as compared with the conventional semiconductor laser device.

The above-described structure is changed to InG of 660 nm band.
Even when applied to an aAlP-based semiconductor laser device, a sufficient effect was obtained. The semiconductor laser device of the ninth embodiment had an oscillation wavelength of 633 nm and a threshold current of 12 mA, and was able to greatly reduce the threshold current of the conventional 660 nm band InGaAlP-based red semiconductor laser device.

In the semiconductor laser device of the ninth embodiment, the Si-doped GaAs layer 2 is formed as a current confinement layer.
A very strong real refractive index waveguide structure without light absorption by the substrate or the current confinement layer can be obtained.

(Embodiment 10) FIG. 10 shows a semiconductor laser device of Embodiment 10. The semiconductor laser device according to the tenth embodiment is obtained by applying the present invention to a ZnMgSSe-based blue semiconductor laser device in the 470 nm band.

In this semiconductor laser device, a groove similar to that of the first embodiment is formed on the (100) plane of a p-type GaAs substrate 1, and a Si-doped GaAs current confinement layer 2 is formed on the substrate 1. In the Si-doped current confinement layer 2, a portion formed on a groove region (shaded portion) having a plane orientation of (111) A shows p-type conductivity and a plane orientation of (4).
11) The portion formed on the groove region of A, on the bottom surface of the groove with the plane orientation of (100) and on the (100) plane on both outer sides of the groove shows n-type conductivity.

On the Si-doped current confinement layer 2, a p-type Z
_{n S Mg 1-S S T} Se 1-T cladding layer 3 (e.g., S = 0.7
5, T = 0.42), Zn M Mg 1-M S N Se 1-N active layer 4
(E.g., M = 1, N = 0 ), n -type _{Zn U Mg 1-U S V} S
The e _{1 -V} cladding layer 5 (U = 0.75, V = 0.42) and the n-type GaAs contact layer 6 are laminated in this order.

The cladding layers 3 and 5 are formed of a material having a larger forbidden band width than the active layer 4, and the cladding layer 3, the active layer 4 and the cladding layer 5 constitute a light emitting laminate.

In the semiconductor laser device of the tenth embodiment, the flat part of the active layer 4 becomes the light emitting part. This light emitting portion is surrounded by cladding layers 3 and 5 having a large energy gap and a small refractive index, and has a real refractive index waveguide structure. Also, since the current path is narrowed to the width of the hatched portion,
The threshold current can be greatly reduced as compared with the conventional semiconductor laser device.

The above structure is changed to ZnM of 470 nm band.
A sufficient effect can be obtained even when applied to a gSSe-based semiconductor laser device. The semiconductor laser device of Example 10 had an oscillation wavelength of 478 nm and a threshold current of 20 mA, which were sufficiently lower than the threshold current of a conventional ZnMgSSe-based blue semiconductor laser device in the 470 nm band.

In the semiconductor laser device of the tenth embodiment, the current confinement layer is a Si-doped GaAs current confinement layer 2
However, even if a current confinement layer similar to that of Examples 2 to 7 is formed, a very strong real refractive index waveguide structure without light absorption by the substrate and the current confinement layer can be obtained.

(Embodiment 11) FIG. 11 shows a semiconductor laser device of Embodiment 11. In the semiconductor laser device of the eleventh embodiment, a groove similar to that of the first embodiment is formed on the (100) plane of the p-type GaAs substrate 1, and the Si-doped GaAs current confinement is formed on the substrate 1 so as to fill the groove. Layer 2 is formed. The Si-doped current confinement layer 2 has a plane orientation of (11
1) On the side surface 100 of the groove A (shaded portion), p-type conductivity is exhibited, and the side surface 10 of the groove having the plane orientation of (411) A
1. On the bottom surface 102 of the groove having a plane orientation of (100) and the outer surface 103 of the groove, n-type conductivity is exhibited.

On the Si-doped current confinement layer 2, a p-type A
l _x Ga ₁ -x As cladding layer 3 (for example, X = 0.5
0), the Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.1
4) and Si-doped Al _L Ga _1-L As clad layer 10
(For example, L = 0.50) is laminated to form a light emitting laminated portion. The Si-doped cladding layer 10 is formed on the side surface 100 of the groove having a plane orientation of (111) A (shaded portion).
A region corresponding to the side surface 101 of the groove having a plane orientation of (411) A and a groove having a plane orientation of (100) exhibit p-type conductivity in part or all of the region corresponding to Corresponding to the bottom surface 102 and the outer surface 10 of the groove
The region corresponding to No. 3 shows n-type conductivity.

An n-type GaAs contact layer 6 is formed on the light emitting laminated portion. Further, the p-type substrate 1
A p-side electrode 12 is formed on the side, and an n-side electrode 13 is formed on the n-type contact layer 6 side.

In the semiconductor laser device of the eleventh embodiment, the current path in the Si-doped cladding layer 10 is confined to a p-type conductive portion (hatched portion), so that the spreading current flowing in the lateral direction can be further suppressed. The threshold current can be greatly reduced as compared with the semiconductor laser device of the first embodiment. However, if the p-type region formed in the Si-doped current confinement layer 10 is p-type in all layer thickness directions, a pn junction is formed at the hetero junction, so that a leak current may occur. In this case, as shown in FIG. 11, the p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction.

The semiconductor laser device of the tenth embodiment is
When fabricated as a DH structure in the nm band, the threshold current was 5 m
A was obtained.

(Embodiment 12) FIG. 12 shows a semiconductor laser device of Embodiment 12. In the semiconductor laser device of the twelfth embodiment, a groove similar to that of the first embodiment is formed on the (100) plane of the p-type GaAs substrate 1, and the substrate 1 is filled so as to fill the groove.
Si doped on Al _Z Ga _1-Z As the current confinement layer 7 (e.g. Z = 0.10), p-type Ga _X Al _1-X As cladding layer 3,
An Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.14) and a Si-doped Al _L Ga _1-L As clad layer 10 (for example, L = 0.50) are formed in this order. The Si-doped current confinement layer 7 has a smaller forbidden bandwidth than the Al _Y Ga _1-Y As active layer 4 (for example, Y = 0.14). The contact layer 11a formed on the Si-doped cladding layer 10 is made of Si-doped GaAs.

The Si-doped current confinement layer 7, the Si-doped cladding layer 10, and the Si-doped contact layer 11a
In the above, the region (hatched portion) on the side surface of the groove having the plane orientation of (111) A indicates p-type conductivity, and the plane orientation is (41).
1) The region on the side surface of the groove A, the bottom surface of the groove whose plane orientation is (100) and the region on the outer surface of the groove show n-type conductivity. Other structures can be similar to those of the eleventh embodiment.

In this semiconductor laser device, since the current confinement layer 7 is made of AlGaAs, the light emitted from the active layer 4 is suppressed from being absorbed by the current confinement layer as compared with the semiconductor laser device of the eleventh embodiment. Can be. Therefore, p-type Ga
_{Since the X} Al _{1 -X} As clad layer 3 can be formed thin to suppress the spread current in the horizontal direction, the threshold current can be further reduced.

The current path is confined to the p-type portion (hatched portion) not only in the Si-doped cladding layer 10 but also in the contact layer 11a, so that the spreading current flowing in the lateral direction can be further reduced. However, if the p-type region formed in the contact layer 11a is made to be p-type in all layer thickness directions, a leak current may be generated from the electrode portion. In this case, as shown in FIG. The p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction.

Embodiment 13 FIG. 13 shows a semiconductor laser device of Embodiment 13. In the semiconductor laser device of the thirteenth embodiment, the Si-doped AlP
Ga _1-K As (for example, K = 0.50) is formed. This Si-doped current confinement layer 17 is made of Al _Y Ga _1-Y A
The forbidden band width is larger than that of the s active layer 4 (for example, Y = 0.14), and the p-type Al _x Ga ₁ -x As clad layer 3 (for example, X = 0.50) and the Si-doped Al _L Ga _1-L A
The forbidden band width is equal to or smaller than that of the s-cladding layer 10 (for example, L = 0.50). This Si-doped current confinement layer 1
The light emitting laminated portion is formed on 7. In some or all of the Si-doped current confinement layer 17 and the Si-doped Al _L Ga _{1 -L} As clad layer 10, the plane orientation is (1).
11) A region (shaded area) on the side surface of the groove which is A indicates p-type conductivity, and the region on the side surface of the groove whose surface orientation is (411) A
The regions on the bottom surface of the groove having the plane orientation of (100) and on the (100) plane on both outer sides of the groove show n-type conductivity. However, if the p-type region formed in the Si-doped cladding layer 10 is p-type in all layer thickness directions, a pn junction is formed at the hetero junction, which may cause a leak current. In this case, as shown in FIG. 13, the p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction. Other structures can be similar to those of the eleventh embodiment.

In the semiconductor laser device of the thirteenth embodiment, instead of a current confinement layer having a large refractive index such as a GaAs layer, for example, a Si-doped Al _K Ga _{1 -K} As current confinement layer having a small refractive index and a large energy gap is used. Since the current confinement is performed by 17, a real refractive index waveguide structure without light absorption by the substrate 1 or the current confinement layer having a large refractive index is formed. Therefore, the light extraction efficiency is improved, and the threshold current can be reduced.

(Embodiment 14) FIG. 14 shows a semiconductor laser device of Embodiment 14. The semiconductor laser device according to the fourteenth embodiment has a Si-doped GaAs as a Si-doped current confinement layer.
A current confinement layer 2 and an Al layer on the Si-doped GaAs layer 2
_The forbidden band width is larger than that of the YGa ₁ -YAs active layer 4 (for example, Y = 0.14), and the p-type Al _X Ga _{1 -X} As clad layer 3 (for example, X = 0.5) and Si Doped Al _W Ga
_A Si-doped Al _P Ga _1-P As clad layer 8 (for example, P = 0.50) having the same or smaller forbidden band width as the _1-W As clad layer 10 (for example, W = 0.5) is formed. . In some or all of the Si-doped GaAs current confinement layer 2, the Si-doped cladding layer 8, and the Si-doped cladding layer 10, the region (shaded portion) on the side surface of the groove having the (111) A plane orientation is p. The surface orientation is (10) on the side surface of the groove having the (411) A orientation.
0) (100) on the bottom surface of the groove as the plane and on both outer sides of the groove.
The region on the surface shows n-type conductivity. However, if the p-type region formed in the Si-doped cladding layer 10 is p-type in all layer thickness directions, pn
Since a junction may be formed, a leak current may be generated. In this case, as shown in FIG. 14, the p-type region formed corresponding to the side surface of the groove is partially covered in the layer thickness direction. It should just stay. Other structures can be similar to those of the eleventh embodiment.

In the semiconductor laser device of the fourteenth embodiment, the current confinement is performed not only on the Si-doped current confinement layer 2 but also on the Si-doped cladding layer 8. A real refractive index waveguide structure with little light absorption by the substrate 1 and the current confinement layer can be formed. Therefore,
Since the spreading current in the horizontal direction can be suppressed, the threshold current can be further reduced.

(Embodiment 15) FIG. 15 shows a semiconductor laser device of Embodiment 15. In the semiconductor laser device of Example 15, a Si-doped GaAs current confinement layer 2 and a Si-doped Al _Q Ga _{1 -Q} As light confinement layer 9 (for example, Q = 0.60) are formed as current confinement layers. . This Si-doped light confinement layer 9 is a p-type Al _x Ga ₁ -x As clad layer 3
(For example, X = 0.5) and Si-doped Al _L Ga _1-LA
The forbidden band width is larger than that of the s-cladding layer 10 (for example, L = 0.5). In some or all of the Si-doped current confinement layer 2, the Si-doped light confinement layer 9, and the Si-doped cladding layer 10, the region (shaded area) on the side surface of the groove having the (111) A plane orientation is a p-type. And the plane orientation is (10) on the side surface of the groove having the plane orientation of (411) A.
The region on the bottom surface of the groove, which is 0), and on the (100) plane on both sides of the groove show n-type conductivity. However, if the p-type region formed in the Si-doped cladding layer 10 is p-type in all layer thickness directions, a pn junction is formed at the hetero junction, which may cause a leak current. In this case, as shown in FIG. 15, the p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction. Other structures can be similar to those of the eleventh embodiment.

The light confinement layer 9 is a p-type cladding layer 3
Since the refractive index is smaller and the energy gap is larger, a very strong real refractive index waveguide structure without light absorption by the substrate 1 or the current confinement layer can be obtained. Therefore, the current spreading in the horizontal direction is suppressed, and the light extraction efficiency can be increased, so that the threshold current can be further reduced.

(Embodiment 16) FIG. 16 shows a semiconductor laser device of Embodiment 16. The semiconductor laser device of Example 16 is obtained by applying the present invention to a 630 nm band InGaAlP-based red semiconductor laser device.

In this semiconductor laser device, the contact layer 11a formed on the light emitting laminated portion is formed of Si-doped Ga.
Consists of As. In part or all of the Si-doped current confinement layer 2 and the Si-doped contact layer 11a,
A region (shaded area) on the side surface of the groove having the plane orientation of (111) A indicates p-type conductivity, and the side surface of the groove having the plane direction of (411) A and the groove having the plane direction of (100). And the region on the outer surface of the groove shows n-type conductivity. However,
If the p-type region formed in the Si-doped contact layer 11a is made to be p-type in all layer thickness directions, a leak current may be generated from the electrode portion. In this case, as shown in FIG. The p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction. Other structures can be similar to those of the eleventh embodiment.

The above structure is used for the InG of 630 nm band.
Even when applied to an aAlP-based semiconductor laser device, a sufficient effect was obtained. In the semiconductor laser device of Example 16, the threshold current was 12 mA at the oscillation wavelength of 633 nm, and the threshold current of the conventional 630 nm band InGaAlP-based red semiconductor laser device could be significantly reduced.

In the semiconductor laser device of the sixteenth embodiment, the Si-doped GaAs layer 2 is formed as a current confinement layer. However, even if a current confinement layer similar to that of the twelfth to fifteenth embodiments is formed, the substrate 1 or the current confinement layer may be formed. And a very strong real refractive index waveguide structure without light absorption due to the above.

(Embodiment 17) In the embodiment 17, 470n
An m-band ZnMgSSe-based blue semiconductor laser device to which the present invention is applied is employed. FIG. 17 shows a semiconductor laser device of Example 17 of the present invention.

In this semiconductor laser device, the contact layer 11a formed on the light emitting laminated portion is made of Si-doped Ga.
Consists of As. In part or all of the Si-doped current confinement layer 2 and the Si-doped contact layer 11a,
A region (shaded area) on the side surface of the groove having the plane orientation of (111) A indicates p-type conductivity, and the side surface of the groove having the plane direction of (411) A and the groove having the plane direction of (100). And the region on the outer surface of the groove shows n-type conductivity. However,
If the p-type region formed in the Si-doped contact layer 11a is made to be p-type in all layer thickness directions, a leak current may be generated from the electrode portion. In this case, as shown in FIG. The p-type region formed corresponding to the side surface of the groove may be limited to a partial range in the layer thickness direction. Other structures can be similar to those of the eleventh embodiment.

The above structure is changed to ZnM of 470 nm band.
Even when applied to a gSSe-based semiconductor laser device, a sufficient effect was obtained. The semiconductor laser device of the seventeenth embodiment has an oscillation wavelength of 478 nm and a threshold current of 20 mA.
The threshold current of the ZnMgSSe-based blue semiconductor laser device in the 70 nm band was significantly reduced.

In the present embodiment 17, the Si-doped GaAs current confinement layer 2 is formed as the current confinement layer. However, even if the same current confinement layer as that described in the above-described embodiments 12 to 15 is formed, It is possible to obtain a real refractive index waveguide structure with high luminous efficiency, in which light absorption by the substrate 1 and the current confinement layer is suppressed.

In each of the above embodiments, GaAlAs,
The mixed crystal ratio of InGaAlP and ZnMgSSe may be appropriately changed. Further, the material system of the semiconductor layer is not limited to those described in each embodiment, and any material system using a GaAs substrate can be applied to all semiconductor materials. For example, AlGaInN-based, ZnCdSSe-based, Cu (Al
Various material systems such as Ga) (SSe) ₂ can be used. Further, the composition ratio of the compound can be appropriately changed.

The active layer may have a quantum well structure, and the light emitting layered portion has a SCH (Separat) provided with an optical guide layer.
e Confident Heterostructure
re) Structure and GRIN (Graded Index)-
It may have an SCH structure.

Further, the mixing ratio of the etching solution used for forming the groove may be appropriately changed, and another etching solution such as a mixed solution of ammonia and hydrogen peroxide or a combination thereof may be used. Good.

[0121]

As is apparent from the above description, in the semiconductor laser device of the present invention, the current injection region is formed at least among the side surfaces of the groove having a plurality of side surfaces having a plurality of plane directions formed on the substrate. Since the current can be limited to an area on one or more planes, the current spreading in the horizontal direction can be significantly reduced. In terms of optical characteristics, the central part of the active layer is
AlGaAs with large energy gap and small refractive index
Since it is surrounded by the s cladding layer, it has a real refractive index waveguide structure with little light loss. Therefore, it is possible to increase the light extraction efficiency of the semiconductor laser element and realize a lower threshold.

[Brief description of the drawings]

FIGS. 1A to 1F are diagrams showing a manufacturing process of a semiconductor laser device of Example 1. FIGS.

FIG. 2 is a cross-sectional view illustrating a semiconductor laser device according to a second embodiment.

FIG. 3 is a cross-sectional view illustrating a semiconductor laser device according to a third embodiment.

FIG. 4 is a sectional view showing a semiconductor laser device according to a fourth embodiment.

FIG. 5 is a sectional view showing a semiconductor laser device according to a fifth embodiment.

FIG. 6 is a sectional view showing a semiconductor laser device according to a sixth embodiment.

FIG. 7 is a sectional view showing a semiconductor laser device of Example 7;

FIG. 8 is a sectional view showing a semiconductor laser device according to an eighth embodiment.

FIG. 9 is a sectional view showing a semiconductor laser device of Example 9;

FIG. 10 is a sectional view showing a semiconductor laser device of Example 10;

FIG. 11 is a view showing a manufacturing process of the semiconductor laser device of Example 11;

FIG. 12 is a sectional view showing a semiconductor laser device of Example 12;

FIG. 13 is a sectional view showing a semiconductor laser device of Example 13;

FIG. 14 is a sectional view showing a semiconductor laser device of Example 14;

FIG. 15 is a sectional view showing a semiconductor laser device of Example 15;

FIG. 16 is a sectional view showing a semiconductor laser device of Example 16;

FIG. 17 is a sectional view showing a semiconductor laser device of Example 17;

FIG. 18 is a graph showing the dependence of conductivity on substrate temperature and As pressure.

FIGS. 19A to 19G are diagrams showing a manufacturing process of a conventional semiconductor laser device.

[Explanation of symbols]

 Reference Signs List 1 p-type GaAs substrate 2 Si-doped GaAs current confinement layer 3 p-type cladding layer 4 active layer 5 n-type cladding layer 6 n-type GaAs contact layer 7, 17 Si-doped AlGaAs current confinement layer 8, 10 Si-doped AlGaAs cladding layer 9 Si Doped AlGaAs light confinement layer 11 resist 11a Si-doped GaAs contact layer 12 p-side electrode 13 n-side electrode 15 stripe 100 side surface 101 side surface 102 low surface 103 outside groove 110 shaded portion 111 current confinement layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-196807 (JP, A) JP-A-6-140715 (JP, A) JP-A-6-90060 (JP, A) JP-A-2- 103989 (JP, A) Japanese Patent Laid-Open No. 1-10083 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 5/00-5/50

Claims (14)

(57) [Claims] 1. An active layer comprising at least a first semiconductor layer, a second semiconductor layer having a larger band gap than the first semiconductor layer and a second semiconductor layer having a larger band gap than the first semiconductor layer. 3. A semiconductor laser device having a light emitting laminated portion sandwiched between semiconductor layers of No. 3 and a groove having a bottom portion and both side portions on the surface of a p-type GaAs substrate having a surface with a (100) plane as a surface. Are formed, and the plane orientation of the bottom surface is (100), and each side surface is formed as two or more surfaces having different plane orientations in the depth direction of the groove. A current confinement layer formed to exhibit p-type conductivity on at least one or more surfaces of the side surface portions and to exhibit n-type conductivity on surfaces other than the one or more surfaces; A semiconductor laser device in which the light emitting lamination is formed on a current confinement layer. 2. An activity comprising at least a first semiconductor layer.
A second semiconductor layer having a larger band gap than the first semiconductor layer.
A semiconductor layer having a larger forbidden band width than the first semiconductor layer;
Semiconductor having a light emitting laminated portion sandwiched between semiconductor layers 3
In the semiconductor laser device, the light emitting lamination portion is at least Si-doped AlGaAs.
A cladding layer, at least one of the side surfaces of the groove;
A part or the whole area in the layer thickness direction in the clad layer region corresponding to one or more surfaces shows p-type conductivity, and the surface of the substrate connected to the other surface of the side surface of the groove and the edge of the groove. A semiconductor laser device in which the region of the cladding layer corresponding to (a) has an n-type conductivity. 3. An activity comprising at least a first semiconductor layer.
A second semiconductor layer having a larger band gap than the first semiconductor layer.
A semiconductor layer having a larger forbidden band width than the first semiconductor layer;
Semiconductor having a light emitting laminated portion sandwiched between semiconductor layers 3
In the semiconductor laser device, a Si-doped GaAs contact layer is formed on the light emitting laminated portion, and a layer thickness direction in a region of the contact layer corresponding to at least one or more of side surfaces of the groove A part or all of the part shows p-type conductivity,
A semiconductor laser device in which a region of the contact layer corresponding to another surface of the side surface of the groove and a surface of the substrate connected to an edge of the groove has n-type conductivity. 4. The semiconductor laser device according to claim 1, wherein said Si-doped current confinement layer comprises at least a GaAs layer. 5. The semiconductor according to claim 1, wherein the Si-doped current confinement layer comprises at least an AlGaAs layer, and a bandgap of the AlGaAs layer is smaller than a bandgap of the first semiconductor layer. Laser element. 6. The Si-doped current confinement layer is made of AlGaAs.
s layer, wherein the forbidden band width of the AlGaAs layer is larger than at least the forbidden band width of the first semiconductor layer and is equal to the forbidden band width of the second semiconductor layer and the third semiconductor layer. 4. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is small. 7. The Al-doped current confinement layer comprises at least a GaAs layer and an AlGaAs layer.
3. The forbidden band width of the aAs layer is larger than the forbidden band width of the first semiconductor layer, and is equal to or smaller than the forbidden band width of the second semiconductor layer and the third semiconductor layer.
Or a semiconductor laser device according to item 3. 8. The Si-doped current confinement layer includes at least a first AlGaAs layer and a second AlGaAs layer, and the forbidden band width of the first AlGaAs layer is the forbidden band width of the first semiconductor layer. Smaller than the second AlGaAs
4. The semiconductor laser device according to claim 1, wherein the forbidden band width of the s layer is equal to or smaller than the forbidden band widths of the second semiconductor layer and the third semiconductor layer. 9. The Si-doped current confinement layer comprises at least GaAs, a first AlGaAs layer and a second AlGa
The first AlGaAs layer has a bandgap larger than the bandgap of the second semiconductor layer and the third semiconductor layer, and the bandgap of the second AlGaAs layer is larger than the bandgap of the second AlGaAs layer. 4. The semiconductor laser device according to claim 1, wherein the forbidden band width of each of the second semiconductor layer and the third semiconductor layer is equal to or smaller than the forbidden band width. 10. The Si-doped current confinement layer comprises at least GaAs and an AlGaAs layer.
The forbidden band width of the As layer is the same as that of the second semiconductor layer and the third bandgap.
4. The semiconductor laser device according to claim 1, wherein the forbidden band width of the semiconductor layer is larger than that of the semiconductor layer. 11. The Si-doped current confinement layer comprises at least a first AlGaAs layer, a second AlGaAs layer, and a third AlGaAs layer.
The forbidden band width of the s layer is smaller than that of the first semiconductor layer, and the forbidden band width of the second AlGaAs layer is smaller than the second band gap.
And the forbidden band width of the third AlGaAs layer is equal to or smaller than the forbidden band width of the second semiconductor layer and the third semiconductor layer. Item 4. The semiconductor laser device according to item 1, 2 or 3. 12. A semiconductor device comprising: a second semiconductor layer having a larger forbidden band width than the first semiconductor layer; and a forbidden band larger than the first semiconductor layer. In a method for manufacturing a semiconductor laser device having a light emitting laminated portion sandwiched between a third semiconductor layer having a large width, at least a surface of a p-type GaAs substrate having a surface having a plane orientation of (100) is provided. By performing etching using two or more types of etchants, a groove having a bottom surface portion and both side surface portions is formed with the bottom surface portion having a plane orientation (100),
Forming each side surface as two or more surfaces having different plane orientations in the groove depth direction; and forming a Si-doped current confinement layer on the substrate on which the groove is formed.
Forming p-type conductivity on at least one or more of the side surfaces and n-type conductivity on surfaces other than the one or more surfaces; Forming the light emitting laminated portion on the constriction layer. 13. The light-emitting lamination portion includes at least a Si-doped AlGaAs cladding layer, and a portion in a layer thickness direction in a region of the cladding layer corresponding to at least one or more of side surfaces of the groove or The entire region shows p-type conductivity, and the region of the clad layer corresponding to the other surface of the groove and the surface of the substrate connected to the edge of the groove is formed so as to show n-type conductivity. A method for manufacturing a semiconductor laser device according to claim 12. 14. A step of forming a Si-doped GaAs contact layer on the light emitting laminated portion, wherein a part or the entire region of the contact layer in the layer thickness direction exhibits p-type conductivity. 13. The semiconductor laser device according to claim 12, wherein a region of the contact layer corresponding to the other surface of the side surface of the groove and a surface of the substrate connected to an edge of the groove has n-type conductivity. Production method.