JPH09232674A - Semiconductor laser system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the temperature characteristics by a method wherein an active layer, a contact layer, diffusion preventive layers, etc., are formed so as to have parallel layers and oblique layers with a main plane of a substrate while specifying the region removing the protrusions such as clad layers, etc., to be high resistant regions. SOLUTION: A buffer layer 102, a clad layer 103, a lower part diffusion preventive layer 104, an active layer 105, an upper part diffusion preventive layer 106, another clad layer 107, a spike preventive layer 108, a contact layer 109, etc., are formed on a substrate 101 having a protrusion 113. Next, the region removing the protrusion of the clad layer 107 to the contact layer 109 is implanted with protons to form a high resistant region 112. On the other hand, the region of the active layer 105 in parallel with the main plane of the substrate 101 becomes a natural superlattice while the natural superlattice in the oblique region of the active layer 105 is disordered thereby making the band energy gap in the oblique region larger than that in the protrusion surface region. With such constitution, the carrier and light are confined by the protrusion surface and in the horizontally lateral direction to reduce the threshold value current for enhancing the temperature characteristics.

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 used for optical communication, optical information processing and the like.

[0002]

2. Description of the Related Art For example, JP-A-6-188506 discloses a semiconductor laser using an AlGaInP-based material as a visible semiconductor laser. FIG. 9 is a diagram showing a configuration example of such a semiconductor laser. Referring to FIG. 9, this semiconductor laser device has an n-type GaAs substrate 1, an n-type GaAs buffer layer 2, an n-type AlGaInP clad layer 3, a GaInP active layer 4, and a p-type AlGaInP.
The cladding layers 5 are sequentially stacked, and p-type AlGaI
Ridge stripes are formed on the nP clad layer 5. Then, p-type GaInP is formed on the top of this ridge.
An intermediate layer 6 is formed, and n-type Ga is formed on both sides of the ridge.
An As current narrowing layer 7 is provided. Furthermore, p-type Ga
A p-type GaAs contact layer 8 is formed on the InP intermediate layer 6 and the n-type GaAs current narrowing layer 7. Further, an electrode 9 is formed on the p-type GaAs contact layer 8 and an electrode 10 is formed on the back surface of the substrate 1.

In the semiconductor laser having such a structure, since the n-type GaAs current narrowing layer 7 is formed, the current flows through the ridge stripe portion of the cladding layer 5 into the active layer 4, The active layer 4 is made to emit light.
Further, the n-type GaAs current narrowing layer 7 absorbs the light emitted from the active layer 4, so that a loss difference is formed between the ridge and the outside thereof, thereby providing a refractive index waveguide type semiconductor laser. be able to.

However, the semiconductor laser device as shown in FIG. 9 does not have a horizontal lateral carrier confinement mechanism in the active layer 4. Therefore, carriers injected into the active layer 4 (current flowing into the active layer 4) are diffused in the horizontal direction, and the gain region width is widened. The carriers injected into the region apart from the ridge stripe do not contribute to the laser oscillation, so that the extra carriers are injected and it is difficult to reduce the oscillation threshold current.

A typical structure having a horizontal lateral carrier confinement mechanism is a BH structure (buried heteristru).
Cture) and a structure using a disordering technique by impurity diffusion as disclosed in JP-A-6-53604 are well known. FIG. 10 is a diagram showing a configuration example of an AlGaInP-based semiconductor laser to which a disordering technique by impurity diffusion is applied. Referring to FIG. 10, this semiconductor laser device has an n-type GaAs substrate 1, an n-type GaAs buffer layer 2, an n-type GaInP buffer layer 11, and an n-type AlI.
nP clad layer 12, undoped AlGaInP lower optical confinement layer 13, undoped GaInP active layer 4 (thickness ~ 100Å), undoped AlGaInP upper optical confinement layer 14, p-type AlInP clad layer 15, p-type GaI.
The nP buffer layer 16 and the p-type GaAs contact layer 8 are sequentially stacked. In FIG. 10, 17 is S
It is an i layer and has a Si diffusion region 19 formed by heat treatment. Further, 18 is a SiO ₂ layer.

In the semiconductor laser of FIG. 10, S in the lower optical confinement layer 13, the active layer 4 and the upper active layer 14 is used.
The i diffusion region 19 is disordered to be a quaternary mixed crystal of AlGaInP. Therefore, in the quaternary mixed crystal region of the active layer 4, the bandgap energy is higher than in the GaInP region which is the ternary mixed crystal, so that a heterojunction is formed in the horizontal direction of the active layer. As a result, the carriers injected into the active layer 4 are confined in the ternary mixed crystal region having a narrow band gap energy. Further, since the active layer formed by quaternary mixed crystal has a lowered refractive index, a refractive index waveguide is also formed at the same time.

Further, in FIG. 10, in order to prevent dislocation from occurring after impurity diffusion at the interface between the AlGaAs-based crystal and the AlGaInP-based crystal, the Si diffusion region 19 has the G region.
The contact with the aAs contact layer 8 is avoided. For that purpose, the Si layer 17, the contact layer 8, the Si
It is necessary to precisely pattern the O ₂ layer 18 three times.

As the AlGaInP-based laser, there has been proposed a refractive index guided laser to which a technique for disordering a superlattice structure without using impurity diffusion is applied. FIG.
FIG. 1 is a sectional view of a semiconductor laser disclosed in Japanese Patent Laid-Open No. 5-183231. Referring to FIG. 11, in this semiconductor laser, an n-type GaAs substrate 1 having a {100} plane orientation is used.
A stripe-shaped convex portion 22 having inclined side surfaces is formed on the. Then, on the n-type GaAs substrate 1,
n-type AlGaInP cladding layer 3, non-doped GaIn
P active layer 4, p-type AlGaInP clad layer 5, p-type G
The aInP contact layer 20 is sequentially formed by vapor phase epitaxial growth. Then, the p-type Ga of the convex portion
A p-type GaAs cap layer 21 is provided on the InP contact layer 20. In addition, in FIG.
Reference numerals 10 are p-side and n-side electrodes, respectively.

In general, AlGaIn formed on a GaAs substrate having a {100} plane orientation by a vapor phase epitaxial growth method.
It is known that the P layer is formed as a natural superlattice structure. On the other hand, when a crystal is grown on a plane inclined with respect to the {100} plane such as {511}, {311}, or {111} plane, a natural superlattice is not formed. The band cap energy is larger than that of the layer grown on the {} plane. The semiconductor laser of FIG.
This principle is utilized, and in FIG. 11, the upper portion of the convex portion 22 of the substrate 1 is the {100} surface, and the side surface of the convex portion 22 is an inclined surface. Therefore, it was grown on the inclined surface. The AlGaInP clad layer 3 and the GaInP active layer 4 are
The band cap energy is larger than the upper portion of the convex portion 22. Therefore, it is a refractive index guided semiconductor laser in which carriers are confined in the active layer region above the convex portion.

[0010]

However, the conventional AlGaInP-based semiconductor laser has a problem that the cladding layer is a quaternary mixed crystal and therefore has a larger thermal resistance and device resistance than the AlGaAs-based semiconductor laser. In addition, GaInP that is an active layer and AlG that is a clad layer
Since the band discontinuity of the conduction band with aInP is small, there is also a problem that electrons easily overflow from the active layer.

Therefore, in the AlGaInP semiconductor laser, p-type AlGaIn is used to improve the temperature characteristics.
It is necessary to increase the doping concentration of the P layer, but p-type A
When the doping concentration of the lGaInP layer is increased, the dopant diffuses during the crystal growth and the p-type A on the {100} plane is
Since the natural superlattice of the 1GaInP clad layer is disordered and the band gap energy difference between the upper surface and the side surface of the convex portion disappears, the current cannot be narrowed in the p-type AlGaInP clad layer. In addition, GaIn
When the dopant diffuses from the clad layer to the P active layer, the active layer region on the upper surface of the convex portion is also disordered, and the band gap energy difference from the inclined surface disappears.
It becomes impossible to realize a refractive index guided laser.

The present invention can maintain a good current narrowing function and realize a refractive index guided laser even when the doping concentration of the cladding layer is increased to improve the temperature characteristics. An object is to provide an AlGaInP-based semiconductor laser device.

[0013]

In order to solve the above-mentioned object, in the invention according to claim 1, a GaAs substrate of the first conductivity type having a {100} plane as a main plane and provided with stripe-shaped projections or depressions. A first conductivity type AlGaInP clad layer, an undoped AlGaInP lower diffusion prevention layer, an undoped AlGaInP active layer, and an undoped AlGaIn.
The P upper diffusion prevention layer, the second conductivity type AlGaInP clad layer, and the second conductivity type GaAs contact layer are sequentially arranged so as to have a crystal plane parallel to the main plane of the substrate and an inclined surface inclined to this crystal plane. The region of the contact layer and the second-conductivity-type cladding layer excluding the concave portions or convex portions is a high resistance region. Thereby, even when the doping concentration of the cladding layer is increased to improve the temperature characteristics, carriers can be favorably confined, and a stable refractive index waveguide structure can be provided.

According to the second aspect of the invention, {10
Substrate having a first-conductivity-type GaAs substrate having a 0-plane plane as a main plane and provided with stripe-shaped recesses, and an insulating layer formed on the surface of the substrate excluding the recesses, and not covered with the insulating layer. The first conductivity type AlGaInP clad layer, the undoped AlGaInP lower diffusion preventing layer, and the undoped Al in the recess.
The GaInP active layer, the undoped AlGaInP upper diffusion barrier layer, the second conductivity type AlGaInP clad layer, and the second conductivity type GaAs contact layer have a crystal plane parallel to the main plane of the substrate and an inclined surface inclined to this crystal plane. To
They are sequentially stacked. Thereby, even when the doping concentration of the cladding layer is increased to improve the temperature characteristics, carriers can be favorably confined, and a stable refractive index waveguide structure can be provided.

According to the third aspect of the invention, {10
0} plane as a main plane and a first conductivity type GaAs substrate, and an insulating layer having a stripe-shaped opening in the substrate, and the first conductivity type AlGaInP clad layer on the substrate at the stripe-shaped opening. , Undoped AlGaInP
Lower diffusion prevention layer, undoped AlGaInP active layer, undoped AlGaInP upper diffusion prevention layer, second conductivity type A
The lGaInP clad layer and the second conductivity type GaAs contact layer were formed in the stripe-shaped opening in a crystal plane parallel to the principal plane of the substrate and obliquely to this crystal plane.
1} A plane, and are sequentially laminated. Thereby, even when the doping concentration of the cladding layer is increased to improve the temperature characteristics, carriers can be favorably confined, and a stable refractive index waveguide structure can be provided.

According to the invention of claim 4, {10
0} plane as the main plane on the first conductivity type GaAs substrate, the first conductivity type AlGaInP cladding layer, the second conductivity type AlG
An aInP current blocking layer and a first conductivity type GaInP cap layer are sequentially stacked, and the cap layer and the current blocking layer are formed by etching to a depth such that the bottoms thereof reach the first conductivity type AlGaInP cladding layer. An undoped AlGaInP lower diffusion prevention layer, an undoped AlGaInP active diffusion layer, an undoped AlGaInP upper diffusion prevention layer, a second conductivity type AlGaI are formed on the first conductivity type cladding layer and the cap layer along the stripe-shaped recess.
The nP clad layer and the second conductivity type GaAs contact layer are sequentially stacked. As a result, even when the doping concentration of the cladding layer is increased to improve the temperature characteristics,
Carriers can be satisfactorily confined and a stable refractive index waveguide structure can be provided.

According to the invention of claim 5, {10
0} plane as the main plane and a first conductivity type GaAs substrate on which stripe-shaped projections or recesses are provided
GaInP clad layer, undoped AlGaInP lower diffusion prevention layer, undoped AlGaInP active layer, undoped AlGaInP upper diffusion prevention layer, second conductivity type AlG
The aInP clad layer and the AlGaInP current blocking layer are sequentially stacked so as to have a crystal plane parallel to the principal plane of the substrate and a slope inclined with respect to this crystal plane, and the upper surface of the convex portion of the current blocking layer. Alternatively, the GaAs contact layer of the second conductivity type is formed on the bottom surface of the recess, and the AlGaInP current blocking layer formed on the slope is of the first conductivity type, and the current formed on the surface parallel to the main plane of the substrate. The block layer has the second conductivity type. Thereby, even when the doping concentration of the cladding layer is increased to improve the temperature characteristics, carriers can be favorably confined, and a stable refractive index waveguide structure can be provided.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. In the following example, Se is used as the n-type dopant and Zn is used as the p-type dopant. FIG. 1 shows a first semiconductor laser device according to the present invention.
FIG. 3 is a diagram showing an example of the configuration of FIG. Referring to FIG. 1, this semiconductor laser device has an n-type Ga having a {100} plane as a main plane.
A stripe-shaped convex portion 113 is formed on the As substrate 101. The side surface of the convex portion 113 is a surface inclined from the {100} surface, for example, a {111} surface, a {311} surface, a {511} surface, or the like.

On the substrate 101 having the convex portion 113, a Se-doped GaAs buffer layer 102, a Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 103, and an undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Lower diffusion prevention layer 104, undoped Ga _0.5 In _0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion prevention layer 106, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 107, Zn Doped GaInP spike prevention layer 1
08, Zn-doped GaAs contact layer 109 is sequentially stacked. At this time, MO is used as a crystal growth method.
A CVD (metal organic chemical vapor deposition) method is used, whereby each growth layer is formed by bending along the convex shape of the substrate. In addition, the GaAs contact layer 109, the GaInP spike prevention layer 108, the p-type Al
In the GaInP clad layer 107, protons are implanted in the region excluding the convex portion, and the high resistance region 112 is formed. Further, on the GaAs contact layer 109, the p-side ohmic electrode 11 made of Au—Zn / Au is formed.
0 is formed on the back surface of the substrate 101.
An n-side ohmic electrode 111 made of e / Ni / Au is formed.

According to the configuration example of FIG. 1, the proton is AlG.
Since the high resistance region 112 is formed by being implanted right above the aInP upper diffusion prevention layer 106, the current concentrates on the convex portion without spreading in the p-type cladding layer 107. As a result, G which is the {100} surface on both outsides of the convex portion
It is possible to prevent carriers from being injected into the aInP active layer 105.

Furthermore, the upper surface of the convex portion is a {100} surface parallel to the principal plane of the substrate, and the side surface of the convex portion is a surface inclined from the {100} surface. Therefore, as mentioned above,
GaIn crystal-grown on the {100} plane by MOCVD
The P active layer 105 has a natural superlattice structure, while the GaInP active layer 105 crystal-grown on the inclined surface has a disordered natural superlattice. Thereby, GaIn on the upper surface of the convex portion
Compared to the P active layer 105, the GaInP active layer 1 having an inclined surface
In No. 05, the band gap energy is increased by about 50 meV, so that carriers are confined in the GaInP active layer 105 on the upper surface of the convex portion. The refractive index is {10
The GaInP active layer 105 on the 0} plane is more G on the inclined plane.
Since the height is higher than that of the aInP active layer 105, at the same time when the carriers are confined, a refractive index waveguide is formed to confine light. In this way, carriers and light can be confined in the same region in the horizontal and horizontal directions, so that the threshold current can be reduced. That is, a low threshold current operation of the laser can be realized.

Further, in the configuration example of FIG. 1, since the undoped AlGaInP diffusion prevention layers 104 and 106 are formed above and below the GaInP active layer 105, the cladding layer 10 is formed.
Even if the carrier concentration of 3,107 is set to 3 × 10 ¹⁸ cm ⁻³ or more, Zn or Se as a dopant does not diffuse into the GaInP active layer 105. This allows
The natural superlattice structure of the GaInP active layer 105 on the {100} plane is not disordered, and it is possible to stabilize the carrier confinement mechanism and the refractive index waveguide structure. Therefore, the doping concentration of the p-type clad layer 107 can be increased, and in this case, the element resistance can be reduced, so that the generation of Joule heat in the p-type clad layer can be reduced. In addition, since the conduction band discontinuity between the active layer 105 and the p-type cladding layer 107 can be increased, the effect of confining carriers, that is, electrons is increased,
The temperature characteristics of the element can be improved.

FIG. 2 is a diagram showing a second configuration example of the semiconductor laser device according to the present invention. In the semiconductor laser of FIG.
Stripe-shaped recesses 201 are formed in an n-type GaAs substrate 101 whose main plane is the {100} plane. Recess 20
The side surface of 1 is a surface inclined from the {100} surface, for example, {11
It is a 1} plane, a {311} plane, a {511} plane, or the like.

Then, on the substrate 101 having the recess 201, the Se-doped GaAs buffer layer 102 and the Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P are formed by MOCVD.
Cladding layer 103, undoped (Al _0.7 Ga _0.3 ) _0.5 I
n _0.5 P lower diffusion preventing layer 104, undoped Ga _0.5 In
_0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 I
n _0.5 P upper diffusion preventing layer 106, Zn-doped (Al _0.7 G
a _0.3 ) _0.5 In _0.5 P cladding layer 107, Zn-doped Ga
The InP spike prevention layer 108 and the Zn-doped GaAs contact layer 109 are sequentially stacked. GaA
s contact layer 109, GaInP spike prevention layer 10
In the p-type AlGaInP cladding layer 107, protons are implanted in the p-type AlGaInP cladding layer 107 except for the bottom surface of the recess, and the high resistance region 1
12 are formed. In addition, the GaAs contact layer 1
A p-side ohmic electrode 110 made of Au—Zn / Au is formed on the substrate 09, and on the back surface of the substrate 101,
N-side ohmic electrode 1 made of Au-Ge / Ni / Au
11 is formed.

In the configuration example of FIG. 2 as well, as in the configuration example of FIG. 1, proton implantation is performed to form the high resistance region 112, thereby constricting the current, and GaIn.
Although undoped AlGaInP diffusion prevention layers 104 and 106 are formed above and below the P active layer 105, in the configuration example of FIG. 2, a stripe-shaped recess 201 is formed in the substrate 101, and the active layer is formed thereon by MOCVD. The GaInP active layer 105 is formed by forming the laminated structure containing
Has a {100} plane that is bent along the concave shape of the substrate 101 and is parallel to the main plane of the substrate 1, and a plane that is inclined from the {100} plane.

In this case, the GaInP active layer 105 crystal-grown on the {100} plane by the MOCVD method has a natural superlattice structure, whereas the GaInP active layer 105 crystal-grown on the inclined plane has a natural superlattice suppressed. Since it is disordered, the band gap energy of the GaInP active layer 105 having the inclined surface is larger than that of the GaInP active layer 105 having the {100} surface. Therefore, the GaInP is concentrated in the recess 201 by the high-resistance region 112 for proton implantation.
The carriers injected into the active layer 105 are confined in the bottom surface of the recess in the GaInP active layer 105. Also, GaI
The refractive index of the nP active layer 105 is higher on the bottom surface of the concave portion than on the inclined surface. Therefore, at the same time when the carriers are confined, a refractive index waveguide can be formed to confine light. The current can be reduced. That is, a low threshold current operation of the laser can be realized.

Further, as in the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

FIG. 3 is a diagram showing a third configuration example of the semiconductor laser device according to the present invention. In the configuration example of FIG. 3, {10
On the n-type GaAs substrate 101 whose main plane is the 0} plane.
_{The x} film 301 is formed. <0 for the SiN _x film 301
A striped window is formed in the 1-1> direction.
The aAs substrate 101 is provided with stripe-shaped recesses 201 formed by wet etching the GaAs substrate 101 using the SiN _x film 301 as a mask. The bottom surface of the recess 201 is a {100} plane parallel to the principal plane of the substrate, and the side surface thereof is a surface inclined from the {100} plane.

Then, in the recess 201, MOCVD is performed.
Of the Se-doped GaAs buffer layer 102, Se
Doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 10
3, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower diffusion prevention layer 104, undoped Ga _0.5 In _0.5 P active layer 10
5, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion preventing layer 106, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5
A P-clad layer 107, a Zn-doped GaInP spike prevention layer 108, and a Zn-doped GaAs contact layer 109 are sequentially stacked.

Here, the SiN _x film 301 functions as an insulating layer and also serves as a mask layer for selective epitaxial growth by the MOCVD method. Therefore, epitaxial growth is performed on the SiN _x film 301. Instead, the crystal growth is selectively performed only in the portion of the recess 201 where the surface of the GaAs substrate 101 is exposed. In addition, each growth layer is formed by bending along the concave shape of the substrate. Further, a p-side ohmic electrode 110 made of Au—Zn / Au is formed on the SiN _x film 301 and the GaAs contact layer 109, and n made of Au—Ge / Ni / Au is formed on the back surface of the substrate 101. The side ohmic electrode 111 is formed.

According to the configuration example of FIG. 3, the DH structure including the active layer 105 is selectively epitaxially grown in the stripe-shaped recess 201, and Ga on both outer sides of the recess 201 is formed.
The surface of the As substrate 101 is a SiN _x film 301 which is an insulating layer.
Therefore, the current flows only into the recess 201.

Further, the active layer 105 has a {1
00} surface, and the side surface of the recess is a surface inclined from the {100} surface. The GaInP active layer 105 crystal-grown on the {100} plane by the MOCVD method has a natural superlattice structure, while the GaInP active layer 105 crystal-grown on the inclined plane is disordered by suppressing the natural superlattice. Therefore, the band gap energy of the GaInP active layer 105 having the inclined surface is larger than that of the GaInP active layer 105 having the {100} surface. Therefore, the carriers injected into the active layer 105 are confined in the bottom surface of the recess in the active layer 105. In addition, since the active layer 105 has a higher refractive index on the bottom surface of the concave portion than on the inclined surface, at the same time when the carriers are confined, a refractive index waveguide is formed and light can be confined, thereby reducing the threshold current of the device. It can be reduced.
That is, a low threshold current operation of the laser can be realized.

Also, as in the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

FIG. 4 is a diagram showing a fourth configuration example of the semiconductor laser device according to the present invention. Also in the configuration example of FIG.
As in the configuration example of FIG. 3, n having the {100} plane as the main plane
A SiN _x film 301 is formed on the type GaAs substrate 101,
Although the stripe-shaped window 401 is formed in the <01-1> direction on the SiN _x film 301, in the configuration example of FIG.
Striped window 40 not covered by iN _x film 301
1 at the MOC on the GaAs substrate 101.
By the VD method, the Se-doped GaAs buffer layer 102,
Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P clad layer 1
03, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower diffusion prevention layer 104, undoped Ga _0.5 In _0.5 P active layer 1
05, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion preventing layer 106, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In
_0.5 P clad layer 107, Zn-doped GaInP spike prevention layer 108, Zn-doped GaAs contact layer 10
9 are sequentially stacked.

Here, the SiN _x film 301 functions as an insulating film and also serves as a mask layer for selective epitaxial growth by the MOCVD method. Therefore, epitaxial growth is performed on the SiN _x film 301. Without the GaAs substrate 10 of the striped window portion 401.
(1) Crystal growth is selectively performed only in a portion where one surface is exposed. Since the stripes are formed in the <01-1> direction, the selectively grown crystal layer has a {100} plane parallel to the principal plane of the substrate and a {111} A tilted from the {100} plane. The face is crystal-grown, and the {111} B face which is a growth stop face appears on the side face. Further, the {111} B surface having the inverse taper shape is filled with polyimide 402, and the p-side ohmic electrode 110 made of Au—Zn / Au is formed on the polyimide 402 and the GaAs contact layer 109. An n-side ohmic electrode 111 made of Au-Ge / Ni / Au is formed on the back surface of the substrate 101.

According to the configuration example of FIG. 4, the DH structure including the active layer 105 is selectively epitaxially grown on the striped window portion 401, and the surface of the GaAs substrate 101 on both outer sides of the striped window portion 401 is an insulating layer. SiN _x
The film 301 and the polyimide 402 are covered. Therefore,
The current will flow only into the striped window portion 401.

Further, in the active layer 105 formed by selective growth, {100} planes and {111} A planes appear. Ga grown on the {100} plane by MOCVD
The InP active layer 105 has a natural superlattice structure, while {1
Since the GaInP active layer 105 crystal-grown on the 11} A plane is disordered by suppressing the natural superlattice, {10
The GaI of the {111} A plane is higher than that of the GaInP layer of the 0 plane.
The band gap energy of the nP layer is large. Therefore, the carriers injected into the active layer 105 are confined in the {100} plane in the active layer 105. Also,
The refractive index of the active layer 105 is {10} compared to the {111} A plane.
Since the 0} plane is higher, a refractive index waveguide is formed at the same time when the carriers are confined, light can be confined, and the threshold current of the device can be reduced. That is, a low threshold current operation of the laser can be realized.

Further, as in the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

FIG. 5 is a diagram showing a fifth configuration example of the semiconductor laser device according to the present invention. In the configuration example of FIG. 5, {10
On the n-type GaAs substrate 101 whose main plane is the 0} plane.
e-doped GaAs buffer layer 102, Se-doped (Al
_0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 103, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P current blocking layer 50
The 1, Se-doped GaInP cap layer 502 is sequentially stacked. The bottoms of the cap layer 502 and the current block layer 501 have n-type AlGaIn.
Striped recesses 201 are formed by etching so as to reach the P clad layer 103.

Further, in the configuration example of FIG. 5, an undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower portion is formed by MOCVD on the n-type cladding layer 103 and the cap layer 502 in which the stripe-shaped recess 201 is formed. Diffusion prevention layer 1
04, undoped Ga _0.5 In _0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion prevention layer 1
06, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 107, Zn-doped GaInP spike prevention layer 10
8 and a Zn-doped GaAs contact layer 109 are sequentially formed. Then, on the GaAs contact layer 109, a p-side ohmic electrode 11 made of Au—Zn / Au is formed.
0 is formed on the back surface of the substrate 101.
An n-side ohmic electrode 111 made of e / Ni / Au is formed.

FIG. 6 is a diagram showing an example of a manufacturing process of the semiconductor laser device shown in FIG. Referring to FIG. 6, first, as shown in FIG. 6A, n having a {100} plane as a main plane
Type GaAs substrate 101, Se-doped GaAs buffer layer 102, Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P
Cladding layer 103, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 I
n _0.5 P current blocking layer 501, Se-doped GaInP
The cap layer 502 is sequentially epitaxially grown by, for example, the MOCVD method.

Next, as shown in FIG. 6B, GaInP
A photoresist 601 is applied on the cap layer 502, and the photoresist 6 is formed by a photolithography technique.
No. 01 with a stripe-shaped window 602 having a width of 5 μm, and the photoresist 60 having the stripe-shaped window 602 formed therein
Stripe-shaped concave portions 201 are formed by wet etching using 1 as a mask. The etching depth is
It is set so as to reach the n-type AlGaInP cladding layer 103.

Next, after removing the photoresist 601, an undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower portion is formed on the n-type AlGaInP cladding layer 103 and the GaInP cap layer 502 as shown in FIG. 6C. Diffusion prevention layer 10
4, undoped Ga _0.5 In _0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion prevention layer 10
6, Zn-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 107, Zn-doped GaInP spike prevention layer 10
8. The Zn-doped GaAs contact layer 109 is sequentially crystal-grown by the MOCVD method, for example. As a result, the active layer 105 is formed into a shape bent along the shape of the recess 201.

Finally, as shown in FIG. 6D, n-type Ga
On the surface of the As contact layer 109, a p-side ohmic electrode 110 made of Au—Zn / Au is formed by, for example, a vacuum evaporation method, and on the back surface of the substrate 101, Au—Ge /
The semiconductor laser device of FIG. 5 is formed by forming the n-side ohmic electrode 111 made of Ni / Au by, for example, a vacuum vapor deposition method.
Complete the (element).

In the element thus manufactured, that is, in the semiconductor laser device of FIG.
Outside of 01, the p-type AlGaInP current blocking layer 50 is formed.
1 and the n-type GaInP cap layer 502 are present,
It has a pnpn structure. Therefore, both holes and holes are blocked by the reverse bias junction, and the current can be concentrated in the recess 201.

In addition, the GaInP active layer 105 has the recess 2
It bends along the shape of 01 and is parallel to the main plane of the substrate {10
It has a 0 plane and a plane inclined from the {100} plane. Here, the GaInP active layer 105 crystal-grown on the {100} plane by the MOCVD method has a natural superlattice structure, while the GaInP active layer 105 crystal-grown on the inclined plane is disordered with the natural superlattice suppressed. Therefore, {10
The band gap energy of the slanted GaInP layer is larger than that of the 0} plane GaInP layer. Therefore, the carriers are confined in the bottom surface of the recess in the active layer 105.

Further, the refractive index of the active layer 105 is higher on the bottom surface of the concave portion than on the inclined surface. Further, since the GaInP cap layer exists on both outer sides of the recess, the light generated in the active layer 105 suffers absorption loss. By these effects, a complex refractive index waveguide is formed and light can be confined.

Further, as in the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

FIG. 7 is a diagram showing a sixth configuration example of the semiconductor laser device according to the present invention. In the configuration example of FIG. 7, {10
Stripe-shaped convex portions 113 are formed on a p-type GaAs substrate 701 whose main plane is the 0} plane. At this time, the stripe-shaped convex portion 113 is formed parallel to the <01-1> direction, and the side surface of the convex portion 113 is a surface inclined from the {100} plane in the <011> direction.

Then, on the substrate 701, a Zn-doped GaAs buffer layer 702, a Zn-doped Ga _0.5 In _0.5 P buffer layer 703, and a Zn-doped layer are formed by MOCVD.
(Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 107, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower diffusion prevention layer 1
04, undoped Ga _0.5 In _0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion prevention layer 1
06, Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 103 and (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P current blocking layer 704 are sequentially stacked. Then, an Se-doped GaAs contact layer 705 is provided on the upper surface of the convex portion, and the n-side ohmic electrode 111 made of Au—Ge / Ni / Au is provided on the surface of the GaAs contact layer 705 and the current block layer surface 704. However, the p-side ohmic electrode 110 made of Au—Zn / Au is formed on the back surface of the substrate 701.

AlGaIn grown by MOCVD
In the P layer, the incorporation efficiency of the dopant differs depending on the crystal plane orientation. When tilted from the {100} plane to the <011> direction, the incorporation efficiency of Zn which is a p-type dopant increases, The incorporation of Se, which is an n-type dopant, reduces the efficiency. Therefore, in the configuration example of FIG. 7, the efficiency of Zn incorporation is increased and the efficiency of Se incorporation is decreased on the side surface of the concave portion inclined in the <011> direction from the {100} plane. Therefore, when the AlGaInP current blocking layer 704 is crystal-grown, the raw material supply amounts of Zn and Se are controlled so that Zn and Se are supplied at the same time. The inclined surface (horizontal line portion in the figure) can be formed to be p-type. That is, the AlGaInP current blocking layer formed on the inclined surface can be formed as a p-type, and the AlGaInP current blocking layer formed on a surface parallel to the main plane {100} of the substrate can be formed as an n-type.

In this case, the n-side electrode 111 is made of n-type GaA.
It forms an ohmic contact with the s contact layer 705, but forms a Schottky junction with the AlGaInP current blocking layer 704. Therefore, the current is injected from the GaAs contact layer 705 formed on the upper surface of the convex portion. On the side surface of the convex portion, the current blocking layer 704 is p-type, so that the structure is an npnp structure and no current flows.
(Can block current). On the other hand, since the current blocking layer 704 is n-type on the upper surface of the convex portion, current flows into the active layer 105 through the n-type cladding layer 103 and the diffusion prevention layer 106.

Furthermore, the GaInP active layer 105 crystal-grown on the {100} plane by the MOCVD method has a natural superlattice structure, while the GaInP active layer 105 crystal-grown on the inclined plane has a natural superlattice disordered. There is. As a result, compared with the GaInP layer on the upper surface of the convex portion, the GaI on the inclined surface is
The band gap energy of the nP layer becomes large, and the carriers are confined on the upper surface of the convex portion in the active layer 105. In addition, the refractive index of GaIn on the {100} plane is higher than that of the inclined plane.
Since the P layer is higher, the refractive index waveguide can be formed at the same time when the carriers are confined, and the threshold current of the device can be reduced. That is, a low threshold current operation of the laser can be realized.

In addition, as in the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

FIG. 8 is a diagram showing a seventh configuration example of the semiconductor laser device according to the present invention. In the configuration example of FIG. 8, {10
Stripe-shaped recesses 201 are formed in a p-type GaAs substrate 701 whose main plane is the 0} plane. At this time, the stripe-shaped recess 201 is formed in parallel with the <01-1> direction, and the side surface of the recess 201 is a surface inclined from the {100} plane in the <011> direction.

Then, on the substrate 701, a Zn-doped GaAs buffer layer 702, a Zn-doped Ga _0.5 In _0.5 P buffer layer 703, and a Zn-doped layer are formed by MOCVD.
(Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 107, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P lower diffusion prevention layer 1
04, undoped Ga _0.5 In _0.5 P active layer 105, undoped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P upper diffusion prevention layer 1
06, Se-doped (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layer 103 and (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P current blocking layer 704 are sequentially stacked.

Here, the AlGaInP current blocking layer 7
In the same manner as in the configuration example of FIG. 7, reference numeral 04 controls the supply amounts of Zn and Se raw materials during crystal growth by the MOCVD method, and
By supplying n and Se at the same time, one growth,
The {100} plane can be formed to be n-type, and the side surface of the recess (horizontal line portion in the drawing) can be formed to be p-type. An Se-doped GaAs contact layer is provided on the bottom surface of the recess, and an n-side ohmic electrode 111 made of Au-Ge / Ni / Au is formed on the surfaces of the GaAs contact layer 705 and the current block layer 704. On the back surface of the substrate 101, a p-side ohmic electrode 1 made of Au—Zn / Au is formed.
10 are formed.

In the configuration example of FIG. 8, current is injected from the GaAs contact layer 705 formed on the bottom surface of the recess, narrowed down to the bottom surface of the recess by the current blocking layer 704, and passes through the n-type cladding layer 103 and the diffusion prevention layer 106. Active layer 10
Pour into 5. The carriers injected into the active layer 105 are
It is confined to the bottom of the recess where the band gap energy is smaller than the side surface of the recess. Further, since the refractive index of the active layer 105 is higher on the bottom surface of the concave portion than on the inclined surface, at the same time when the carriers are confined, a refractive index waveguide is formed to confine light. Therefore, the threshold current of the device can be reduced. That is, a low threshold current operation of the laser can be realized.

Further, similarly to the first configuration example, the active layer 10
5 above and below the undoped AlGaInP
The diffusion prevention layers 104 and 106 can prevent the dopant Zn or Se of the cladding layer from diffusing into the active layer 105 and disordering the natural superlattice of the GaInP active layer 105. Therefore, the p-type cladding layer 10
The doping concentration of 7 can be increased, and the temperature characteristics of the device can be improved.

As described above, in each of the above-described constitutional examples, the band gap energy of the AlGaInP active layer on the slope can be made larger than the band gap energy on the {100} plane, and the active layer was injected into the active layer. Since carriers can be confined in the {100} plane region where the band gap energy is small (because injected carriers can be concentrated in the active layer region on both sides of the {100} plane sandwiched by slopes). The low threshold current operation of the laser can be realized.

Further, the refractive index of the GaInP active layer on the {100} plane is higher than that of the AlGaInP active layer on the inclined surface, so that the refractive index waveguide structure is formed in self-alignment with carrier confinement. It can be operated in stable horizontal and horizontal modes.

A is formed above and below the AlGaInP active layer.
Since the lGaInP diffusion prevention layer is formed, the dopant of the cladding layer is not diffused into the active layer even if the doping concentration of the cladding layer is increased, and the carrier confinement mechanism and the refractive index waveguide structure described above are not lost. . And
By increasing the doping concentration of the p-type cladding layer, the device resistance can be reduced and the conduction band discontinuity between the active layer and the p-type cladding layer can be increased, so that the temperature characteristics of the device can be improved.

Although the active layer is a GaInP layer in each of the above-described configuration examples, a GaInP layer other than the GaInP layer is used as long as the bandgap energy of the active layer is smaller than that of the diffusion prevention layer and the cladding layer. For example, the active layer may be an AlGaInP layer or the like. The structure in the vicinity of the active layer is not limited to the DH structure, and may be a quantum well structure, a multiple quantum well structure, a strained quantum well structure, or the like.

Further, the above-mentioned first to fifth configuration examples (see FIG. 1)
6 to 6), an n-type substrate is used, the first conductivity type is n-type, and the second conductivity type is p-type.
Depending on the case, the first conductivity type may be p-type and the second conductivity type may be n-type.

Further, the above-mentioned sixth and seventh configuration examples (FIG. 7,
In the configuration example of FIG. 8, a p-type substrate is used, the first conductivity type is p-type, and the second conductivity type is n-type. However, depending on the case, the first conductivity type is n-type, The second conductivity type may be p-type.

[0066]

As described above, according to the first aspect of the present invention, the first conductivity type GaAs substrate having stripe-shaped convex portions or concave portions with the {100} plane as the main plane is provided. First conductivity type AlGaInP clad layer, undoped AlGaInP lower diffusion prevention layer, undoped AlGa
The InP active layer, the undoped AlGaInP upper diffusion preventing layer, the second conductivity type AlGaInP clad layer, and the second conductivity type GaAs contact layer form a crystal plane parallel to the main plane of the substrate and an inclined surface inclined to this crystal plane. To have,
Since the high resistance region is formed by sequentially stacking the contact layer and the second conductivity type clad layer excluding the concave portion or the convex portion, even when the doping concentration of the clad layer is increased to improve the temperature characteristics. The carrier can be satisfactorily confined and a stable refractive index waveguide structure can be provided.

According to the invention of claim 2, {1
A substrate having a first conductivity type GaAs substrate having a stripe-shaped concave portion with the {00} plane as a main plane and an insulating layer formed on the surface of the substrate excluding the concave portion and not covered with the insulating layer. A first conductivity type AlGaInP clad layer, an undoped AlGaInP lower diffusion preventing layer, and an undoped A are formed in the recess.
lGaInP active layer, undoped AlGaInP upper diffusion prevention layer, second conductivity type AlGaInP clad layer, second
Since the conductivity type GaAs contact layers are sequentially laminated so as to have a crystal plane parallel to the main plane of the substrate and a slope inclined to this crystal plane, the doping of the cladding layer is improved to improve the temperature characteristics. Even when the concentration is increased, carriers can be satisfactorily confined and a stable refractive index waveguide structure can be provided.

According to the invention of claim 3, {1
A first conductivity type GaAs substrate having a {00} plane as a main plane and an insulating layer having a stripe-shaped opening in the substrate,
A first conductivity type AlGaInP clad layer, undoped AlGaIn on the substrate at the stripe-shaped opening.
P lower diffusion prevention layer, undoped AlGaInP active layer,
An undoped AlGaInP upper diffusion preventing layer, a second conductivity type AlGaInP clad layer, and a second conductivity type GaAs contact layer are formed in the stripe-shaped opening and a crystal plane parallel to the main plane of the substrate and oblique to this crystal plane. Was {1
11} A-plane, the layers are sequentially laminated, so that even when the doping concentration of the cladding layer is increased to improve the temperature characteristics, carriers are well confined and a stable refractive index waveguide is provided. It can have a structure.

According to the invention of claim 4, {1
On the first conductivity type GaAs substrate whose main plane is the 00} plane,
First conductivity type AlGaInP cladding layer, second conductivity type Al
A GaInP current blocking layer and a first conductivity type GaInP cap layer are sequentially stacked, and the cap layer and the current blocking layer are formed by etching to a depth such that the bottoms thereof reach the first conductivity type AlGaInP cladding layer. An undoped AlGaInP lower diffusion prevention layer, an undoped AlGaInP active diffusion layer, an undoped AlGaInP upper diffusion prevention layer, a second conductivity type AlGa are formed on the first conductivity type clad layer and the cap layer along the stripe-shaped recess.
Since the InP clad layer and the second-conductivity-type GaAs contact layer are sequentially laminated, even when the doping concentration of the clad layer is increased to improve the temperature characteristics, carriers are well confined and a stable refractive index is obtained. It can have a waveguide structure.

According to the invention of claim 5, {1
On the first conductivity type GaAs substrate having stripe-shaped projections or depressions with the {00} plane as the main plane.
lGaInP clad layer, undoped AlGaInP lower diffusion prevention layer, undoped AlGaInP active layer, undoped AlGaInP upper diffusion prevention layer, second conductivity type Al
The GaInP clad layer and the AlGaInP current block layer are sequentially laminated so as to have a crystal plane parallel to the main plane of the substrate and a slope inclined with respect to this crystal plane, and the upper surface of the convex portion of the current block layer. Alternatively, the GaAs contact layer of the second conductivity type is formed on the bottom surface of the recess, and the AlGaInP current blocking layer formed on the slope is of the first conductivity type, and the current formed on the surface parallel to the main plane of the substrate. Since the block layer is of the second conductivity type, carriers can be well confined and a stable refractive index waveguide structure can be provided even when the doping concentration of the cladding layer is increased to improve the temperature characteristics. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a first configuration example of a semiconductor laser device according to the present invention.

FIG. 2 is a diagram showing a second configuration example of a semiconductor laser device according to the present invention.

FIG. 3 is a diagram showing a third configuration example of a semiconductor laser device according to the present invention.

FIG. 4 is a diagram showing a fourth configuration example of a semiconductor laser device according to the present invention.

FIG. 5 is a diagram showing a fifth configuration example of a semiconductor laser device according to the present invention.

FIG. 6 is a diagram showing an example of a manufacturing process of the semiconductor laser device shown in FIG.

FIG. 7 is a diagram showing a sixth configuration example of the semiconductor laser device according to the present invention.

FIG. 8 is a diagram showing a seventh configuration example of the semiconductor laser device according to the present invention.

FIG. 9 is a configuration diagram of a conventional selective ridge embedded semiconductor laser.

FIG. 10 is a configuration diagram of a semiconductor laser to which a conventional disordering technique by impurity diffusion is applied.

FIG. 11 is a configuration diagram of a semiconductor laser to which a conventional natural superlattice is applied.

[Explanation of symbols]

1 n-type GaAs substrate 2 n-type GaAs buffer layer 3 n-type AlGaInP clad layer 4 GaInP active layer 5 p-type AlGaInP clad layer 6 p-type GaInP intermediate layer 7 n-type GaAs current confinement layer 8 p-type GaAs contact layer 9 p-side electrode Reference Signs List 10 n-side electrode 11 n-type GaInP buffer layer 12 n-type AlInP clad layer 13 undoped AlGaInP lower optical confinement layer 14 undoped AlGaInP upper optical confinement layer 15 p-type AlInP clad layer 16 p-type GaInP buffer layer 17 Si layer 18 SiO ₂ layer 19 Si diffusion region 20 p-type GaInP contact layer 21 p-type GaAs cap layer 22 stripe-shaped convex portion 101 n-type GaAs substrate 102 n-type GaAs buffer layer 103 n-type AlGaInP clad layer 104 undoped A GaInP diffusion prevention layer 105 undoped GaInP active layer 106 undoped AlGaInP diffusion prevention layer 107 p-type AlGaInP clad layer 108 p-type GaInP spike prevention layer 109 p-type GaAs contact layer 110 p-side electrode 111 n-side electrode 112 proton-implanted region 113 striped protrusions Part 201 Striped recess 301 SiN _x film 401 Striped window 402 Polyimide 501 p-type AlGaInP current blocking layer 502 n-type GaInP cap layer 601 photoresist 701 p-type GaAs substrate 702 p-type GaAs buffer layer 703 p-type GaInP buffer layer 704 AlGaInP Current blocking layer 705 n-type GaAs contact layer

Claims (5)

[Claims] 1. A first-conductivity-type AlGaInP clad layer, an undoped AlGaInP lower diffusion preventing layer, and an undoped AlGa on a first-conductivity-type GaAs substrate having a {100} plane as a main plane and stripe-shaped protrusions or depressions.
The InP active layer, the undoped AlGaInP upper diffusion preventing layer, the second conductivity type AlGaInP clad layer, and the second conductivity type GaAs contact layer form a crystal plane parallel to the main plane of the substrate and an inclined surface inclined to this crystal plane. To have,
2. A semiconductor laser device, wherein the contact layer and the second-conductivity-type cladding layer are sequentially laminated, and a region other than a concave portion or a convex portion of the second conductive type cladding layer is a high resistance region. 2. A first-conductivity-type GaAs substrate having a {100} plane as a main plane and having stripe-shaped recesses, and an insulating layer formed on the surface of the substrate excluding the recesses. The first conductivity type AlGaI is formed in the concave portion of the substrate not covered with
nP clad layer, undoped AlGaInP lower diffusion prevention layer, undoped AlGaInP active layer, undoped A
lGaInP upper diffusion prevention layer, second conductivity type AlGaIn
A semiconductor laser in which a P-clad layer and a GaAs contact layer of the second conductivity type are sequentially laminated so as to have a crystal plane parallel to the main plane of the substrate and an inclined surface inclined to this crystal plane. apparatus. 3. A first-conductivity-type GaAs substrate having a {100} plane as a main plane and an insulating layer having a stripe-shaped opening in the substrate, and the stripe-shaped opening on the substrate, A first conductivity type AlGaInP clad layer,
An undoped AlGaInP lower diffusion prevention layer, an undoped AlGaInP active diffusion layer, an undoped AlGaInP upper diffusion prevention layer, a second conductivity type AlGaInP cladding layer, and a second conductivity type GaAs contact layer are crystals parallel to the main plane of the substrate in the stripe-shaped opening. Plane and a {111} A plane formed obliquely with respect to this crystal plane,
A semiconductor laser device characterized by being sequentially laminated. 4. A first conductivity type AlGaInP clad layer, a second conductivity type AlGaInP current blocking layer, and a first conductivity type GaInP cap layer are sequentially formed on a first conductivity type GaAs substrate having a {100} plane as a main plane. The cap layer and the current blocking layer are laminated, and the bottom of the cap layer and the current blocking layer are of the first conductivity type
The undoped AlGaInP lower diffusion prevention layer and the undoped AlG on the first conductivity type clad layer and the cap layer along the stripe-shaped recess formed by etching to a depth that reaches the 1GaInP clad layer.
A semiconductor laser device comprising: an aInP active layer, an undoped AlGaInP upper diffusion preventing layer, a second conductivity type AlGaInP clad layer, and a second conductivity type GaAs contact layer, which are sequentially stacked. 5. A first-conductivity-type AlGaInP clad layer, an undoped AlGaInP lower diffusion prevention layer, and an undoped AlGa are formed on a first-conductivity-type GaAs substrate having a {100} plane as a main plane and stripe-shaped protrusions or depressions.
InP active layer, undoped AlGaInP upper diffusion prevention layer, second conductivity type AlGaInP clad layer, AlGaI
The nP current blocking layers are sequentially laminated so as to have a crystal plane parallel to the main plane of the substrate and a slope inclined with respect to the crystal plane, and the top surface of the convex portion or the bottom surface of the concave portion of the current blocking layer. Has a second conductivity type GaAs contact layer, the AlGaInP current blocking layer formed on the slope is of the first conductivity type, and the current blocking layer formed on a surface parallel to the main plane of the substrate is A semiconductor laser device having a two-conductivity type.