JPH07135374A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To enhance the horizontal traversal mode of a semiconductor laser by a structure wherein the emission region of a V-shaped active layer, i.e., the bottom part, is located under the current path in a current constriction layer comprising n-type and p-type regions. CONSTITUTION:A double heterostructure comprising a V-shaped strained quantum well active layer 26 and p-type clad layers 28, 30 is provided on a compound semiconductor substrate 21 having a main plane (100) in which a V-groove extends in 01-1 direction. Group II acceptor and group VI donor are introduced into the p-type clad layers 28, 30 and a current constriction layer 29 is formed by an n-type region 29A generated by the group VI donor collected on 100 plane a p-type region 29B generated by the group II acceptor collected on the V-groove. The emission region of the V-shaped active layer, i.e., the bottom part, is located under the current path of the current constriction layer 29. This structure realizes stabilized horizontal traversal mode confinement over a wide optical output range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of an AlGaInP-based visible light semiconductor laser device which emits light in a wavelength band of 600 nm.

The semiconductor laser device tends to be used as a light source for writing and reading a high density information recording optical disk or a magneto-optical disk, a light source for a bar code scanner, a laser printer, a pointer, or the like. , In particular, there are great expectations as a light source for magneto-optical disks, but in this application, severe conditions such as low threshold, high light output, high reliability, long life, low aspect ratio, and low astigmatism characteristics Is required, and it is necessary to deal with this.

[0003]

2. Description of the Related Art FIG. 15 shows a standard AlGaInP / Ga.
It is a principal part front view showing an InP loss guide type visible light semiconductor laser device.

In the figure, 31 is an n-GaAs substrate, 3
2 is an n-GaAs buffer layer, 33 is an n-GaInP intermediate layer, 34 is an n-AlGaInP clad layer, 35 is an (Al) GaInP active layer, and 36 is p-AlGaInP.
Clad layer, 37 is p-GaInP intermediate layer, 38 is n-
A GaAs current confinement layer and 39 are p-GaAs contact layers, respectively.

In this semiconductor laser device, by arranging the current confinement layers 38 each having an energy band gap narrower than that of the active layer 35 on both sides above the active layer 35, light generated in the active layer 35 is emitted. The current confinement layer 38 is intentionally absorbed to generate an effective refractive index difference in the lateral direction to realize optical confinement in the lateral direction, which is a so-called loss guide structure.

The above-mentioned semiconductor laser device has a relatively simple structure and has good characteristics in terms of threshold current, efficiency, light output, reliability and the like, but also has the following drawbacks.

The AlGaInP-based visible light semiconductor laser device is a metalorganic vapor phase epitaxy method (metalorgani).
c vapor phase epitaxy method: MO
Although it is formed by the VPE method), the semiconductor laser device requires crystal growth three times, which complicates the manufacturing process.

That is, the semiconductor layers from the buffer layer 32 to the intermediate layer 37 are grown in the first time, the current constriction layer 38 is grown in the second time, and the contact layer 39 is grown in the third time.

Since it has a loss guide structure, the astigmatism is very large, 5 [μm] to 10 [μm], and to correct this, the optical system of the magneto-optical disk drive becomes complicated.

In order to solve the above-mentioned drawbacks, the present inventors have used a stepped substrate to produce a low astigmatism visible light semiconductor laser (self-a) which can be produced by one-time crystal growth.
signed stepped substrate
laser: S ³ laser) (see “Japanese Patent Application No. 4-250280” if necessary).

FIG. 16 is a front view of an essential part for explaining the S ³ laser. In the figure, 41 is an n-GaAs substrate (step substrate), 42 is an n-GaAs buffer layer, and 43 is an n-GaAs substrate.
GaInP intermediate layer, 44 n-AlGaInP clad layer, 45 (Al) GaInP active layer, 46 p-Al
GaInP cladding layer, 47 Zn and Se simultaneous doping current confinement layer, 48 p-GaInP intermediate layer, and 49 p-
Each of the GaAs contact layers is shown.

In this S ³ laser, a substrate 41 whose main surface is inclined in the (100) plane or in the <011> direction from the (100) plane by, for example, about 2 to 10 degrees is used.

A groove is formed in the <01-1> direction on the substrate 41, and the plane orientation on the slope in the groove is (411).
A to (311) A surface.

When Zn and Se are doped at the same time when the current confinement layer 47 is formed on the substrate 41 having the above structure, impurity uptake depends on the plane orientation.
By utilizing the difference, the current confinement layer 47 can be formed only on the (100) plane by self-alignment.

That is, when AlGaInP is simultaneously doped with Zn and Se, the incorporation of Zn is (100).
The (411) A to (311) A planes are about 10 to 20 times higher than the (100) plane, but the Se uptake is about 10 to 20 times higher in the (411) A to (311) A planes than in the (100) plane. It decreases to about 1/5.

Therefore, by appropriately adjusting the respective concentrations of Zn and Se and simultaneously doping, an n-type AlGaInP layer on the (100) plane and (411) A to
On the (311) A plane, p-type AlGaInP layers can be grown.

When the above means is adopted, the stepped substrate, that is,
Of course, the current confinement layer 47 can be formed on the substrate 41 by self-alignment, and since the active layer 45 has a bent shape, a difference in refractive index occurs in the lateral direction, and as a result, astigmatism is maintained until high light output. Can be 1 [μm] or less.
In addition, it has been confirmed that characteristics such as threshold value, efficiency, aspect ratio, and reliability are also excellent.

[0018]

The S ³ laser described with reference to FIG. 16 has very excellent characteristics as described above, but as a result of many experiments, the following problems are apparent. It's coming.

The light distribution during operation tends to concentrate on the bent portion above or below the active layer, and it is difficult to locate the light spot at the center of the slope of the active layer.

The position of the light spot easily fluctuates depending on the magnitude of the drive current, and at the time of this fluctuation, a kink is likely to occur in the current-light output characteristic even when the output is relatively small.

One of the advantages of the low aspect ratio is that, since light is confined in a relatively narrow region of the bend in the active layer, the light density in the active layer is high. , C at the laser end face at low output
OD (catastrophic optical d)
image), it is difficult to obtain a high optical output, and the reliability at the time of high output cannot be ensured.

A window (win) for suppressing COD destruction
It is difficult to introduce the dow) structure.

Usually, in order to suppress the COD breakdown, a means for expanding the energy band gap at the end face portion of the active layer to suppress light absorption at the end face to improve the COD level, that is, a window structure is introduced. Is being done.

A natural superlattice formed in GaInP, or a method of widening the energy band gap by disposing the multiple quantum well active layer by means such as Zn diffusion, or bending the active layer in the vicinity of the end face to form the end face. There is a method called a crank-type window structure that suppresses the absorption of light.

However, in the S ³ laser shown in FIG. 16, the natural superlattice is originally disordered in the energy band in the active layer on the slopes (411) A to (311) A. Since the gap is wide and the element structure is formed on the step substrate, it is difficult to introduce a crank type window structure having a more complicated structure.

The present invention is intended to improve the horizontal transverse mode characteristics in a semiconductor laser device by a simple means, and to easily introduce a crank type window structure to improve the COD level.

[0027]

FIG. 1 and FIG. 2 are front views of a main part of a semiconductor laser device for explaining the principle of the present invention. The semiconductor laser device shown in FIG. 1 has an n-type substrate, and the semiconductor laser device shown in FIG. 2 has a p-type substrate.

In FIGS. 1 and 2, 11 is a substrate and 12 is
Is a buffer layer, 13 is an intermediate layer, 14 is a cladding layer, 15
Is a V-shaped active layer, 16 is a cladding layer, 17 is a current confinement layer, 18 is an intermediate layer, and 19 is a contact layer.

Since some semiconductor layers in the semiconductor laser devices shown in FIGS. 1 and 2 have different conductivity types, each semiconductor layer will be described together with materials.

In FIG. 1, substrate 11: n-type GaAs buffer layer 12: n-type GaAs intermediate layer 13: n-type GaInP cladding layer 14: n-type AlGaInP active layer 15: (Al) GaInP cladding layer 16: p Type AlGaInP current confinement layer 17: co-doped n-type AlGaInP intermediate layer 18: p-type GaInP contact layer 19: p-type GaAs.

In FIG. 2, substrate 11: p-type GaAs buffer layer 12: p-type GaAs intermediate layer 13: p-type GaInP clad layer 14: p-type AlGaInP active layer 15: (Al) GaInP clad layer 16: n. Type AlGaInP current confinement layer 17: co-doped n-type AlGaInP intermediate layer 18: n-type GaInP contact layer 19: n-type GaAs.

FIG. 3 is a photomicrograph for clarifying that the active layer on the substrate in the semiconductor laser device manufactured according to the present invention has a V-shaped pattern in cross section (on the substrate). It represents the formed fine pattern).

FIG. 4 is a perspective view of an essential part showing a substrate in a semiconductor laser device for explaining the principle of the present invention.
The same symbols as those used in FIG. 2 represent the same parts or have the same meanings.

In the figure, 11A is a V-groove with a narrow width provided at both ends in the cavity direction, and 11B is a V-groove 11A with a narrow width.
The wide V-grooves provided between them are shown.

The main surface of the GaAs substrate 11 is the (100) plane, and the V groove is formed in the <01-1> direction. The V groove is formed by selective etching using a mask having a stripe window.

The angle formed by the V-groove and the main surface which is the (100) plane is adjusted to be, for example, about 15 to 20 degrees.

FIG. 5 is a perspective view of an essential part showing each semiconductor layer formed on the substrate in the semiconductor laser device for explaining the principle of the present invention. In FIG. 1, FIG. 2, and FIG. The symbols used are the same or have the same meaning.

FIG. 6 is an explanatory view of a main part of a semiconductor laser device for explaining the principle of the present invention. The same symbols as those used in FIGS. 1 and 2 or 4 and 5 indicate the same parts. Represent or have the same meaning.

In the figure, (A) is a side surface for cutting a main part,
(B) is an energy band diagram, 16A is n
Each of the AlGaInP current non-injection regions is shown.

In (A), as shown in FIGS. 1 and 2 or FIGS. 4 and 5, when the V groove formed in the substrate is narrowed near the end face, the active layer cranks. Reveals.

In (B), it can be seen that the energy band gap of the flat portion is narrower than the energy band gap of the crank portion.

FIG. 7 is a perspective view of an essential part showing a substrate in a semiconductor laser device for explaining the principle of the present invention.
The same symbols as those used in FIGS. 2 and 4 and 5 represent the same parts or have the same meanings.

In the figure, 11C is a wide V groove provided at both ends in the resonator direction, and 11D is a wide V groove 11C.
The narrow V-grooves provided between each are shown.

FIG. 8 is a cutaway side view of a main part of a semiconductor laser device for explaining the principle of the present invention, which is used in FIGS. 1 and 2, 4 and 5, 6 and 7. The symbol and the same symbol represent the same part or have the same meaning.

This semiconductor laser device is manufactured using the substrate shown in FIG. 7, and in this case, the crank state of the active layer is opposite to that in FIG.

Each of the semiconductor layers shown is a V-type AlGaIn
P-DH (double heterostructure)
re) structure and its V-shaped slope is (100)
A plane inclined about 13 degrees from the plane to the (111) A plane, that is, (7
11) A- (511) A surface.

During the growth of each semiconductor layer, the clad layer 14 or 16 in contact with the active layer 15 is simultaneously doped with a group II acceptor (particularly Zn) and a group VI donor (particularly Se), so that (100) The current confinement layer 17 can be formed only on the surface (if necessary, "91P0
8682 "or the above" 92P03352 ").

Metal-organic vapor phase epitaxy
nic vapor phaseepitaxy method: M
When the (OVPE method) is applied, the amount of Zn taken in is higher in the plane inclined in the (111) A plane direction than in the (100) plane, and conversely, the amount of Se taken in is
It becomes lower in the plane inclined in the (111) A plane direction than in the (100) plane.

Therefore, by appropriately selecting the doping concentrations of Zn and Se and performing the simultaneous doping, the p-type is formed in the V groove, that is, the portion where the current flows, and on the (100) plane, That is, since an n-type layer can be obtained in the current confinement portion, the current confinement layer can be self-aligned in the cladding layer by one crystal growth.

As can be understood from the above description, the semiconductor laser device of the present invention is most characterized in that the active layer is V-shaped.

As is clear from FIG. 3, in the V-shaped active layer, the thickness of the V-shaped bent portion, that is, the bottom portion is approximately equal to the thickness of the sloped portion. It becomes about 20% thicker.

At the bottom part, a natural superlattice is formed by reflecting the properties of the (100) plane, and the energy band is higher than that at the slope part, that is, the part where no natural superlattice is generated.
The gap narrows.

A sufficient refractive index difference can be provided in the lateral direction. Etc., with some characteristic configurations,
Due to this configuration, the operation or effect described later occurs.

By the way, the so-called technique of simultaneously doping p-type and n-type dopants when epitaxially growing a semiconductor layer on a stepped substrate was not realized for the first time in the present invention. It is disclosed in U.S. Pat. No. 5,065,200 by Bhat et al. (Filing date November 12, 1991).

In the US patent by Bhat et al., When the semiconductor laser device is viewed from the front, the active layer has a shape in which two V-shaped portions are connected by a flat portion, that is, an inverted gal wing. It has a shape, and the flat portion between the V-shaped portions serves as a light emitting region.

17 and 18 show US Pat. No. 5,063.
It is a principal part front view of the semiconductor laser device seen in 5,200 specification. In the figure, reference numerals 51 and 52 denote light emitting regions generated in a flat portion between two V grooves.

The difference between the US patent based on Bhat et al. And the present invention will be apparent from the description for explaining the principle of the present invention and the following description. In the present invention, the V-shaped active layer is used. Since the bottom part is the light emitting area, the stability of the horizontal transverse mode is incomparably high.

From the above, in the semiconductor light emitting device according to the present invention, (1) a V-shaped groove extending in the <01-1> direction of the main surface which is the (100) plane (for example, for example, Compound semiconductor substrate (for example, n-GaAs substrate 21) having V grooves formed therein
And a V-shaped active layer (eg, strained quantum well active layer 26) and a p-type cladding layer (eg, p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P cladding layers 28 and 30 formed on the compound semiconductor substrate. ) And a double heterostructure containing, and a 6-group donor among 6-group donors (for example, Zn) and 6-group donors (for example, Se) simultaneously introduced into the p-type cladding layer. The n-type region (for example, the n-type portion 29A) and the Group II acceptors, which are generated on the 100) plane, are generated on the V-shaped groove.
Current confinement layer (for example, Zn and Se co-doped (Al _0.7 G) composed of a type region (for example, p-type portion 29B))
a _0.3 ) _0.5 In _0.5 P current confinement layer 29) is interposed, and the bottom of the V-shaped active layer, which is the light emitting region, is located below the current path in the current confinement layer. Feature or

(2) In the above (1), the width of the V-shaped groove is narrowed or becomes zero near at least one end face, and the active layer changes from V-shaped to flat near the end face. It is characterized in that it is bent toward the surface side as well as

(3) In the above (1), the V-shaped groove is enlarged in width in the vicinity of at least one end face, and the active layer is bent toward the substrate in the vicinity of the end face. Or

(4) In the above (1) or (2),
The width of the V-shaped groove is narrowed or becomes zero near at least one end face, and the p-type clad layer changes from V-shaped to flat near the end face, and the conductivity type changes to n-type so that no current is injected. Characterized by forming a region, or

(5) In (1) above, the energy is introduced at the V-shaped bottom portion of the active layer near the end face by introducing impurities from at least the surface near the end face to reach the active layer. -The band gap is wider than the inner side near the end face.

[0063]

By adopting the above means, in the V-shaped active layer, laser oscillation easily occurs at the bottom of the V-shaped active layer.
Moreover, excellent horizontal transverse mode stability can be obtained.

Therefore, the light is stably confined in the bottom portion of the V-shaped active layer, and while the low aspect ratio and the low astigmatism characteristics are maintained, the fluctuation of the light spot position due to the change of the operating current, The occurrence of kinks can be suppressed.

In the semiconductor laser device described above, it is possible to easily introduce a window structure for improving the COD level. That is, the energy band gap at the bottom of the V-shaped active layer reflects the characteristics of the crystal on the (100) plane, and a natural superlattice is generated.

Therefore, by disposing the active layer at the end face portion using Zn diffusion or the like, it is possible to easily construct a window structure for widening the energy band gap.

As shown in FIGS. 4 and 5, the crank-type window structure can be easily constructed by adopting a structure in which the width of the V groove near the end face of the substrate is changed. . That is, when the width of the V-groove on the substrate is narrow near the end face, the V-groove disappears with a thin layer thickness and becomes a completely flat layer structure as compared with the wide portion. You can do it.

Therefore, by adjusting the width of the V groove in the substrate and the layer thickness of the crystal layer to be epitaxially grown, the shape of the active layer when viewed from the vertical side surface as shown in FIG. It is possible to crank the surface side by a maximum of the height of the V groove in the vicinity. On the contrary, as shown in FIG. 7, when the width of the V-groove is wide near the end face, as shown in FIG. It is possible to crank it to the side.

Furthermore, when the width of the V-groove in the substrate is narrow near the end face, the portion of the simultaneous doping current constriction layer formed on the flat surface is completely inverted to the n-type. Therefore, it is possible to prevent current from flowing near the end face, and it is possible to form a so-called current non-injection structure.

As described above, the current confinement layer, the window structure, and the end face non-current injection structure can be realized by self-alignment by one crystal growth step.

[0071]

FIG. 9 is a front view of a main part of a semiconductor laser device for explaining one embodiment of the present invention, and FIG. 10 shows a semiconductor laser device manufactured according to the present invention. 3 is a micrograph (representing a fine pattern formed on a substrate) for clarifying that the active layer in the V shape is V-shaped.

In the figure, 21 is a substrate, 22 is a buffer layer, 23 is an intermediate layer, 24 is a cladding layer, 25 is a guide layer, 26 is a strained quantum well active layer, 27 is a guide layer, 28
Is a clad layer, 29 is a current confinement layer, 29A is an n-type portion,
29B is a p-type portion, 30 is a crank layer, 31 is an intermediate layer,
Reference numerals 32 respectively indicate contact layers.

The main data of each part shown in the figure is as follows. (1) Substrate 21 Material: n-GaAs Surface index: (100) Impurity: Si Impurity concentration: 4 × 10 ¹⁸ [cm ⁻³ ]

(2) Buffer layer 22 Material: n-GaAs Impurity: Si Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 0.5 μm

(3) About the intermediate layer 23 Material: n-Ga _0.5 In _0.5 P Impurity: Si Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 0.1 μm

(4) Clad layer 24 Material: n-((Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Impurity: Si Impurity concentration: 5 × 10 ¹⁷ [cm ⁻³ ] Thickness: 1.5 μm 2.0 [μm]

(5) Guide layer 25 Material: n- (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P Impurity: Si Impurity concentration: 5 × 10 ¹⁷ [cm ⁻³ ] Thickness: 50 [Å] Or Material: Undoped (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P Thickness: 50 [Å]

(6) Strained quantum well active layer 26 Well layer Material: Undoped (Al) GaInP Thickness: 100 [Å] Number of layers: 2 Compressive strain: 0.75 [%] Barrier layer Material: Undoped (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P Thickness: 50 [Å] Number of layers: 1

(7) Guide layer 27 Material: p- (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P Impurity: Zn Impurity concentration: 5 × 10 ¹⁷ [cm ⁻³ ] Thickness: 50 [Å] Or Material: Undoped (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P Thickness: 50 [Å]

(8) Clad layer 28 Material: p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Impurity: Zn Impurity concentration: 5 × 10 ¹⁷ [cm ^-3 ] Thickness: 0.2 [μm]

(9) Concerning current confinement layer 29 co-doped with Zn and Se n-type portion 29A on (100) plane Material: n- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Impurity: Se Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 0.5 [μm] p-type part 29B present on V groove Material: p− (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Impurity: Zn Impurity concentration: 1 × 10 ¹⁸ [cm ^-3 ] Thickness: 0.5 [μm]

(10) About the clad layer 30 Material: p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P Impurity: Zn Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 1.3 [μm]

(11) About the intermediate layer 31 Material: p-Ga _0.5 In _0.5 P Impurity: Zn Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 0.1 μm

(12) Contact layer 32 Material: p-GaAs Impurity: Zn Impurity concentration: 5 × 10 ¹⁸ [cm ⁻³ ] Thickness: 0.5 [μm]

In the first embodiment, the surface index (10
In order to form the V-groove on the substrate 21 made of GaAs whose surface (0) is exposed, a window made of stripes having a width of about 1 [μm] to 2 [μm] extends in the <01-1> direction. S to do
A mask made of iO ₂ or a resist is formed, and the substrate 21 is etched by wet etching using a mixed solution of hydrofluoric acid, hydrogen peroxide and water as an etchant.

In this case, the width at the opening surface of the V groove is 5
[Μm] to 6 [μm], but reflecting the characteristics of the etchant, a flat portion having the same width as the width of the mask is formed at the bottom of the V groove.

In order to perform crystal growth for forming each semiconductor layer on the substrate 21 in which the V groove is formed, a metalorganic vapor phase growth is carried out.
The epitaxy: MOVPE) method may be applied. In that case, trimethylindium (TMIn: In (CH ₃ ) ₃ ) triethylgallium (TEGa: Ga (C ₂ ) is used as the source gas of In, Ga, Al, As, and P. H ₅ ) ₃ ) Trimethylaluminum (TMAl: Al (C
H _{3) 3)} using arsine (AsH ₃₎ phosphine (PH _3).

To perform doping of Zn, Se and Si, dimethyl zinc (DMZn: Zn (C
H ₃ ) ₂ ) or diethyl zinc (DEZn: Zn (C ₂
H ₅ ) ₂ ) Hydrogen selenide (H ₂ Se) Disilane (Si ₂ H ₆ ) Monosilane (SiH ₄ ) or the like is used.

Hydrogen may be used as a carrier gas for the various gases, the growth pressure may be about 50 [Torr], and the growth temperature may be 650 [° C.] to 750 [° C.]. The flat portion formed at the bottom of the V groove in the substrate 21 disappears as the semiconductor layers grow and become thicker.
It becomes a complete V shape.

FIG. 10 is a photomicrograph for clarifying that the semiconductor layers on the substrate having V-grooves in the semiconductor laser device of the embodiment of the present invention have a V-shaped pattern in cross section. (It represents a fine pattern formed on a substrate). In the photograph, the white portion is a semiconductor layer made of p-type crystal, and the black portion is a semiconductor layer made of n-type crystal.

FIG. 11 is a sectional side view of an essential part for explaining an embodiment in which a window structure is introduced into the semiconductor laser device of the present invention. Whether the same symbols as those used in FIG. 9 represent the same parts. Or they have the same meaning. In addition, since the purpose here is to explain the crank of the active layer, in the figure,
There are many omissions other than the major points.

In the illustrated example, the width of the V groove in the substrate 21 is, for example, about 1 [μm] near the end face, and is 2 inside the V groove.
[Μm] The V groove near the end face may be gradually disappeared.

As is clear from the figure, the active layer 26 has about 2
The p-type cladding layer 28 is cranked upward by about [μm] to 3 [μm] and is in contact with the upper side of the active layer 26 near the end face.
N and the n-type current non-injection region 30A are formed in the regions 30 and 30.

FIG. 12 is a cutaway side view of an essential part for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention. The same symbols as those used in FIGS. 9 and 11 are the same. They represent the same part or have the same meaning. still,
Again, there are many omissions in the figures, other than the main points, for the purpose of explaining the cranks of the active layer.

In the illustrated example, the width of the V groove in the substrate 21 is 2 [μm] to 3 [μ] in the vicinity of the end face as compared with the inside.
m] wide.

As is apparent from the figure, the active layer 26 cranks toward the substrate 21, that is, downward. In this example, the current non-injection region cannot be formed.

FIG. 13 is a cutaway side view of a main part for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention. The symbols used in FIGS. 9, 11 and 12 are The same symbol represents the same part or has the same meaning. Since the purpose here is to explain the widening of the end face, there are many omissions in the figure except for the main points.

In the drawing, 33 indicates a Zn diffusion region.

In the illustrated example, near the end face, Zn diffuses in the vapor phase or solid phase until it reaches the active layer 26 from the surface, and an active superlattice in GaInP or an active layer composed of multiple quantum wells is formed. Disorder is generated in the layer 26, and the end face is made wide gap.

For example, in the case of performing vapor phase diffusion, a diffusion mask having a window in the vicinity of the end face is formed, and the whole is enclosed in a quartz ampoule together with a diffusion source such as ZnAs _{2 in a} vacuum, and the temperature is set to 500. It is carried out at [° C] to 700 [° C].

FIG. 14 is a sectional side view of an essential part for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention. The symbols used in FIG. 9, FIG. 11 to FIG. The same symbol represents the same part or has the same meaning. Since the purpose is also to explain the widening of the end face, there are many omissions in the figure except for the main points.

In the figure, 34 is a mask made of SiO ₂ or the like, and 35 is a Zn diffusion region.

In the illustrated example, the mask 3 is selectively formed near the end face.
No. 4 is formed and heat treatment is applied to form Zn contained in the cladding layer 30 or 28 only under the mask 34.
Are diffused into the active layer 26, and a natural superlattice in GaInP,
Alternatively, a disorder is generated in the active layer 26 composed of multiple quantum wells to make the end faces wide gaps.

If GaInAsP is used for the active layer 26, the vicinity of the end face is widened due to As / P interdiffusion between the GaInAsP active layer / AlGaInP clad layer.
You can also make a gap.

[0105]

In the semiconductor laser device according to the present invention, a compound semiconductor substrate having a V-shaped groove is formed,
A double heterostructure formed on the compound semiconductor substrate and including a V-shaped active layer and a p-type clad layer, and a Group II acceptor simultaneously introduced into the p-type clad layer; Among the 6 group donors, 6 group donors (10
0) plane and an n-type region formed together and a group II acceptor are formed together to form a current-confining layer composed of a p-type region formed on a V-shaped groove and a current path in the current-confining layer. A bottom portion, which is a light emitting region in the V-shaped active layer, is located below the.

By adopting the above configuration, the laser light is V
Can be confined to the bottom of the V-shaped active layer,
Stable horizontal transverse mode confinement can be achieved over a wide light output range. Therefore, kink does not occur until high output, low aspect ratio and low astigmatism are realized, and also self-aligned crank type window structure and current non-injection region structure are easily realized, and high optical output and A semiconductor laser device having excellent reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a semiconductor laser device for explaining the principle of the present invention.

FIG. 2 is a main part front view showing a semiconductor laser device for explaining the principle of the present invention.

FIG. 3 is a photomicrograph for clarifying that an active layer on a substrate in a semiconductor laser device manufactured according to the present invention has a V-shaped pattern in a cross section (formed on the substrate. It represents a fine pattern).

FIG. 4 is a perspective view of a main part of a substrate in a semiconductor laser device for explaining the principle of the present invention.

FIG. 5 is a perspective view of a principal part showing each semiconductor layer formed on a substrate in a semiconductor laser device for explaining the principle of the present invention.

FIG. 6 is an explanatory view of a main part of a semiconductor laser device for explaining the principle of the present invention.

FIG. 7 is a perspective view of a main part of a substrate in a semiconductor laser device for explaining the principle of the present invention.

FIG. 8 is a side sectional view showing a main part of a semiconductor laser device for explaining the principle of the present invention.

FIG. 9 is a front view of a main part of a semiconductor laser device for explaining an embodiment of the present invention.

FIG. 10 is a photomicrograph for clarifying that the semiconductor layers on the substrate having the V groove in the semiconductor laser device according to the embodiment of the present invention have a V-shaped pattern in cross section (substrate. It represents a fine pattern formed above).

FIG. 11 is a side sectional view of a main part for explaining an embodiment in which a window structure is introduced into the semiconductor laser device of the present invention.

FIG. 12 is a sectional side view of a main part for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention.

FIG. 13 is a fragmentary side view for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention.

FIG. 14 is a sectional side view of a main part for explaining another embodiment in which a window structure is introduced into the semiconductor laser device of the present invention.

FIG. 15: Standard AlGaInP / GaInP loss
It is a principal part front view showing a guide type visible light semiconductor laser device.

FIG. 16 is a front view of relevant parts for explaining an S ³ laser.

FIG. 17 is a front view of the main part of the semiconductor laser device seen in US Pat. No. 5,065,200.

FIG. 18 is a front view of the main part of the semiconductor laser device seen in US Pat. No. 5,065,200.

[Explanation of symbols]

 21 substrate 22 buffer layer 23 intermediate layer 24 cladding layer 25 guide layer 26 strained quantum well active layer 27 guide layer 28 cladding layer 29 current constriction layer 29A n-type portion 29B p-type portion 30 cladding layer 31 intermediate layer 32 contact layer

Claims (5)

[Claims] 1. A compound semiconductor substrate having a V-shaped groove extending in a <01-1> direction of a main surface which is a (100) plane, and a V-shaped groove formed on the compound semiconductor substrate. A double heterostructure including a p-type clad layer and a p-type clad layer, and a group 6 donor out of the group 2 acceptor and the group 6 donor introduced simultaneously in the p-type clad layer ( 100) plane and an n-type region formed by gathering and a group II acceptor are gathered, and a current constriction layer composed of a p-type region formed on a V-shaped groove is interposed and current in the current confinement layer. A semiconductor laser device characterized in that a bottom portion which is a light emitting region in the V-shaped active layer is located below the path. 2. A V-shaped groove is narrowed or has a width of zero near at least one end face, and the active layer changes from V-shaped to flat near the end face and is bent toward the surface side. The semiconductor laser device according to claim 1, wherein: 3. The semiconductor laser device according to claim 1, wherein the V-shaped groove has a width enlarged near at least one end face and the active layer is bent toward the substrate near the end face. . 4. The V-shaped groove has a width narrowed or becomes zero near at least one end face, and the p-type cladding layer changes from V-shaped to flat near the end face and the conductivity type changes to n-type. 3. The semiconductor laser device according to claim 1, wherein the current non-injection region is formed. 5. An impurity is introduced from the surface near the end face to reach at least the active layer so that the energy band gap at the V-shaped bottom portion of the active layer near the end face is near the end face. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is wider than the inside.