JPH07176785A - Superluminescent diode element and its manufacture - Google Patents

Abstract

PURPOSE:To provide a superluminescent diode element which can emit a large- level super luminescent light and a method for manufacturing it reliably. CONSTITUTION:A step structure with an inclination surface in the waveguide direction of light is provided on the surface of a substrate 1 and an active layer 5 at a region corresponding to an area on the inclination surface is formed thinly. Light cannot be guided easily on the active layer 5 and an effective reflection factor can be fully reduced, thus suppressing laser oscillation. Since a current non-injection part B does not absorb light for application light, a large-level superluminescent light can be obtained. A thin lamination structure can be obtained with a single MBE growth, a window structure with a larger prohibition band width than that of the active layer 5 can be easily manufactured, thus obtaining an improved re-growth interface without any need for re-growth process onto GaAlAs layer with a large Al composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superluminescent diode element used for a light source of an optical fiber gyroscope and a method for manufacturing the same, and more particularly to a superluminescent diode having a window structure for reducing the reflectance of an end face. Regarding the device, the molecular beam epitaxy method (hereinafter,
MBE) in a single growth step.

[0002]

2. Description of the Related Art In the field of optical measurement such as an optical fiber gyro, a light source having a short coherence length is required to reduce phase noise due to Rayleigh scattering in an optical fiber. Higher output is also required. Unlike a semiconductor laser, the super luminescent diode is designed to prevent the return of light due to end face reflection, and to give light that travels in one direction by gain by stimulated emission to amplify the light and emit it from the end face. Type diode. At this time, the seed of stimulated emission is the spontaneous emission light generated by the recombination of the injected carriers, so that light with a short coherence length (wide spectrum width) can be emitted with high output and directivity. It is attracting attention as a light source in the field of optical measurement such as fiber gyro.

In order to obtain a high output with a superluminescent diode, the light generated in the active layer is unidirectionally amplified along the stripe groove without being subjected to positive feedback by the resonator, and It is necessary to prevent the laser oscillation due to the resonator even when a high injection ratio is applied. For that purpose, a structure for reducing the reflectance of light on the end face of the device is required. With such a structure, it is difficult to reproducibly obtain a low reflectance sufficient to suppress laser oscillation with a structure in which a low reflectance coating is simply applied to the end face, and a high-output superluminescent diode light cannot be obtained. There was a problem.

On the other hand, there is a structure in which the light generated in the active layer can be spread and radiated to a window region having a large forbidden band to reduce the effective reflectance.
No. 85 is proposed. This is to form a window region by regrowth, and the manufacturing process of this conventional example will be described below.

FIG. 6 shows a conventional example of a super luminescent diode element having a window region. Figure 6
6B shows a cross section taken along line XX of FIG.
FIG. 6C shows a cross section taken along the line YY of FIG.

As shown in FIG. 6 (a), the super luminescent diode elements differ from each other in the layered structure in two regions divided by line ZZ in the figure. One region is the excitation part A and the other region is the current non-injection part B.

As shown in FIG. 6B, the excitation part A has an n-type GaAs current blocking layer 55 on a p-type GaAs substrate 51.
The p-type GaAs light absorption layers 503 are stacked in this order, and the light absorption layers 503 to the substrate 51 are arranged at the center of the layers in the width direction.
A stripe groove is formed over the area. The p-type Al _0.50 Ga _0.50 As clad layer 5 is formed on these three layers.
4, Al _0.05 Ga _0.95 As active layer 53, n-type Al _0.50 G
a _0.50 As clad layer 52 and n-type Al _0.20 Ga _0.80
An As protective layer 501, an n-type Al _0.45 Ga _0.55 As window layer 502 and an n-type GaAs contact layer 56 are laminated in this order.

On the other hand, the current non-injection portion B is, as shown in FIG. 6C, the substrate 51 in the widthwise center of the p-type GaAs substrate 51.
A groove is formed which is composed of a bottom surface portion having a plane orientation parallel to the bottom surface and both side surface portions which are inclined surfaces. Such a substrate 5
1, an n-type GaAs current blocking layer 55 and a p-type GaAs light absorption layer 503 are stacked in this order. The current blocking layer 55 and the light absorption layer 503 have a substrate 51 at the center in the width direction. A groove structure having the same shape is formed along the groove shape formed in. N-type Al _0.45 G on these three layers
An a _0.55 As window layer 502 and an n-type GaAs contact layer 56 are laminated in this order. Such a super luminescent diode element is manufactured as follows.

First, as the first etching step, p
A groove for forming the current non-injection portion B is formed in the type GaAs substrate 51.

Next, as the first growth step, the n-type GaAs current blocking layer 55 and the p-type GaAs light absorption layer 503 are grown in this order on the substrate 51 by the LPE method (liquid phase growth method).

Then, as a second etching step, a depth is set so that the p-type GaAs substrate 51 is penetrated in the excitation part A and the p-type GaAs substrate 51 is not penetrated in the current non-injection part B. Forming stripe grooves.

Next, as a second growth step, p-type Al is used.
_0.50 Ga _0.50 As clad layer 54, Al _0.05 Ga _0.95 A
s active layer 53, n-type Al _0.50 Ga _0.50 As clad layer 5
2 and n-type Al _0.20 Ga _0.80 As protective layer 501 are sequentially grown.

Then, as a third etching step, only the current non-injection portion B is etched up to the p-type GaAs light absorption layer 503 at the end face portion.

Finally, as the third growth step, MO
N-type Al _0.45 G by CVD method (metal organic chemical vapor deposition method)
The a _0.55 As window layer 502 and the n-type GaAs contact layer 56 are laminated to form a window structure in the current non-injection part B. In this way, a desired super luminescent diode element is obtained.

In the conventional super luminescent diode element as described above, the light guided through the active layer 53 toward the rear surface side of the current non-injection portion B is radiated into the window layer 502 and the end surface thereof is irradiated. Reach The light reflected by the end surface returns to the active layer 53 again, but the ratio of being effectively coupled to the active layer 53 due to the spread when irradiated from the active layer 53 and reflected by the end surface of the current injection part B. Becomes smaller.

Therefore, it is possible to increase the threshold current value of the laser diode and obtain superluminescent diode light having a wide spectrum half width up to a high optical output. Further, since the forbidden band width of the window layer 502 is larger than that of the active layer 53, it is possible to prevent the end face from being destroyed by the heat generated by the absorption of light.

[0017]

However, the conventional super luminescent diode element shown in FIG. 6 has the following two problems.

(1) At least three etching steps and three growth steps are required, resulting in a large number of steps and high cost. The yield is also low.

(2) Since the window layer 502 is grown by MOCVD on the side surfaces of the p-type and n-type cladding layers 54 and 52 having a large Al composition, contamination such as surface oxidation cannot be avoided. Since a good growth interface cannot be obtained, non-radiative recombination easily occurs at the growth interface in terms of characteristics.
This causes deterioration due to heat generation and an increase in drive current.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a superluminescent diode element capable of emitting high-output superluminescent light. It is to provide a manufacturing method for manufacturing it with high reliability.

[0021]

A super luminescent diode device according to the present invention comprises a semiconductor substrate having a step structure having an inclined surface in a light guiding direction and having an active layer including at least a first semiconductor layer. A light emitting laminate in which both surfaces are sandwiched between a second semiconductor layer having a larger forbidden band width than the first semiconductor layer and a third semiconductor layer having a larger forbidden band width than the first semiconductor layer. In the superluminescent diode element having a portion, the light emitting laminated portion is thinly laminated on the slope of the step structure of the semiconductor substrate, and the light emitting laminated portion optical waveguide has a bottom surface portion and both side surface portions. Each of the side surface portions has one or more plane orientations, and the growth layer on the one or more plane orientations exhibits p-type conductivity. The above object is achieved.

In one embodiment, the bottom portion is (10
It has a plane orientation of 0).

A method of manufacturing a super luminescent diode element according to the present invention comprises a step of forming a step structure having an inclined surface in a light guide direction on a (100) plane of a GaAs substrate, and a step of forming the step structure on the substrate. A groove consisting of the bottom part and both side parts,
A step of forming each side surface portion to have one or more plane orientations, and a growth layer on the one or more plane orientations of the trenches has p-type conductivity on the substrate having the trenches. So as to grow either the Si-doped GaAs layer or the Si-doped AlGaAs layer by the molecular beam epitaxy method,
Both sides of the active layer including the first semiconductor layer have a second semiconductor layer having a larger forbidden band width than the first semiconductor layer and a second semiconductor layer having a larger forbidden band width than the first semiconductor layer. And a step of growing a light emitting laminated portion sandwiched by the third semiconductor layer on the slope of the step structure on the semiconductor substrate, thereby achieving the above object.

In one embodiment, the bottom surface of the groove is (10
It is formed so as to have a plane orientation of 0).

[0025]

In the superluminescent diode element of the present invention, a step structure having an inclined surface in the light guiding direction is provided on the surface of the substrate, and the active layer in a region corresponding to the inclined surface is thinly formed. . Since the active layer is formed thin, light is hardly guided in the active layer, and the effective reflectance can be sufficiently reduced. Therefore, laser oscillation can be suppressed.

Further, since the non-current injection section does not absorb the irradiation light, high-output superluminescent light can be obtained.

Since the non-current injection portion can easily have a current non-injection structure, ineffective heat generation and end face destruction do not occur.

In the method for manufacturing a super luminescent diode element of the present invention, a thin laminated structure can be obtained by one MBE growth, so that a window structure having a larger forbidden band width than the active layer can be easily manufactured. be able to. Therefore, a good regrowth interface can be obtained without the need for a regrowth step on the GaAlAs layer having a large Al composition.

[0029]

EXAMPLES Examples of the present invention will be described below. The present invention is not limited to the embodiments.

(Embodiment 1) FIGS. 1 and 2 show the outline of a super luminescent diode element of Embodiment 1 and its manufacturing process. 1A to 1D are schematic views of the manufacturing process, and A and B in FIGS. 2A to 2D are cross-sections taken along line L-L in FIGS. 1A to 1D, respectively. Line MM
The cross section by. A region having a cross section A and separated by a line KK is an excitation part A, and a region having a cross section B is a non-current injection part B.

As shown in A of FIGS. 1 (d) and 2 (d), this super luminescent diode element has a bottom surface ( Has a plane orientation of 100), and each side surface has (1)
11) A groove having a structure having a plane orientation of A is formed. On the substrate 1 of this excitation part A, Si dope GaA
s current confinement layer 2, Si dove Ga _1-x Al _x As clad layer 3 (for example x = 0.05), p-type Ga _1-x Al _x As clad layer 4 (for example x = 0.50), Ga _{1 -x} Al _1-x A
s active layer 5 (eg x = 0.08), n-type Ga _1-x Al _x
As clad layer 6 (eg x = 0.50) and n-type G
The aAs contact layer 7 is laminated in this order.
All of the portions of the substrate 1 of each layer corresponding to the grooves of this substrate 1
A groove structure is formed along the groove.

On the other hand, on the substrate 1 of the non-current injection portion B, as shown in B of FIGS. 1D and 2D, a laminated structure of layers having the same structure as the excitation portion A is formed. However, on the surface of the substrate 1 of the non-current injection part B, the boundary with the excitation part A (line K in FIG.
The inclination in the direction from the portion (indicated by −K) toward the bottom surface of the substrate 1 along the light guiding direction is formed over a certain section. The layer structure laminated on the non-current injection part B has a structure different from that of the excitation part A along the surface structure of the substrate 1 of the non-current injection part B.

An n-type electrode 11 is formed on the outer side of the substrate 1 in both the excitation section A and the non-current injection section B, and a p-type electrode 12 is formed on the outer side of the contact layer 7. .
Such a super luminescent diode element
It is produced as follows.

First, as the first etching step, as shown in FIG. 1A, a (100) p-type GaAs substrate is formed.
A step structure having an inclined surface is formed on the surface along the light guiding direction.

Next, as a second etching step, as shown in FIG. 1B, a groove composed of a bottom surface having a (100) plane orientation and both side surfaces formed of at least one slope. Are formed only in the excitation part A. In the device of Example 1, each side surface of this groove was formed as a slope having a plane orientation of (111) A.

Subsequently, as a growth step, the Si dope GaAs current confinement layer 2 and the Si dove Ga _1-x Al _x As clad layer 3 (for example, x = 0.05) are formed by the MBE method.
2A, both layers 2 and 3 grow so that only the growth layer on the (111) A plane exhibits p-type conductivity as shown by A in FIG. 2C. The reason for this is as follows.

As a feature of the plane having a plane orientation of (n11) A (1≤n≤3), for example, the (111) A plane has a surface covered with Ga having one bond, and the As Has a small sticking coefficient, the impurity Si is bonded to Ga to form As.
Easy to enter the grid position. However, G with one bond
The ease of releasing As adsorbed on a depends on the growth conditions. Under a growth condition in which the substrate temperature is relatively low and the amount of As flux is large, As is less likely to be released, and even if the surface is a (111) A plane covered with Ga having one bond,
May exhibit mold conductivity. Therefore, the plane orientation is (n1
1) Appropriate growth conditions must be selected in order to grow so as to show p-type conductivity on the surface of A (1 ≦ n ≦ 3).

Subsequently, a p-type Ga _1-x Al _x As clad layer 4 (eg x = 0.50), a Ga _1-x Al _1-x As active layer 5 (eg x = 0.08), an n-type The Ga _1-x Al _x As clad layer 6 (for example, x = 0.50) and the n-type GaAs contact layer 7 are sequentially grown, but it is possible to reduce the growth rate on the slope and grow these layers thinly. it can.
This is because the slope formed on the GaAs substrate is the B surface,
It is considered that stabilized As atoms exist on the surface. As for (111) B side, the surface of the substrate is all stabilized A
Although it is covered with s, its ratio becomes smaller as m of the (m11) B surface becomes larger. Therefore, the Ga atom is A
It becomes difficult to react with s and the growth rate becomes small. Also,
When As4 is changed to As2 by using an As cracking cell, the reaction becomes slower, and it is possible to grow thinner.

Finally, the n-type electrode 11 and the p-type electrode 12
Then, if necessary, a low reflectance coating film is formed to obtain the super luminescent diode device of the first embodiment.

In this super luminescent diode element, the active layer 5 is bent at the slope of the step structure as shown in FIG. 1D, and the layers are thinly laminated at this slope.

As shown in A of FIG. 2D, Si dove GaAs on the side surface of the groove of the excitation portion A in which the groove structure is formed.
A current path is formed only in the region of the current confinement layer 2 and the Si dove Ga _1-x Al _x As cladding layer 3. Also, FIG.
In the area indicated by B in (d), there is no current path and the area is a non-current injection section B (window section). The light guided in the active layer 5 of the pumping section A is amplified by the gain of the stimulated emission of the spontaneous emission light generated by the recombination of the injected carriers. But,
Since the active layer 5 is bent on the step, part of the light guided from the active layer 5 of the excitation part A spreads to the window structure of the non-current injection part B as shown in FIG. Is emitted. Therefore, the effective reflectance can be reduced.

Further, since the active layer 5 on the slope of the step structure is thinly laminated, light is hard to be guided, and even a small amount of light finally guided to the rear facet is obliquely reflected by the rear facet to activate the active layer. It is radiated to the outside of 5. Therefore, the light reflection from the rear end face can be almost reduced. When the low reflectance coating film is formed on the rear end face, the light guided to the active layer 5 again can be reduced to a negligible level.

In addition, the non-current injection part B is a non-excitation part where no current is injected by the Si-doped GaAs current confinement layer 2 and the Si-doped GaAlAs cladding layer 3 as can be understood from B of FIG. 2 (d). However, p-type GaA
Since the forbidden band width of the 1As clad layer 4 is set to be larger than that of the light emitted from the active layer 5, the structure of the non-current injection portion (window structure) does not absorb light and can efficiently use the current. it can. Therefore, high-output superluminescent light can be obtained from the end face of the excitation part A.

Further, the flat portion of the active layer 5 serving as the light emitting portion is
Since the real refractive index waveguide structure is surrounded by the GaAlAs clad layer 4 having a large forbidden band width and a small refractive index, the optical loss is reduced and the low drive current operation can be realized.

The superluminescent diode element of Example 1 of the present invention can be manufactured by two etching steps and one MBE growth step, and the window structure is formed on the GaAlAs layer having a large Al composition also in the growth step. A good growth interface can be obtained because it is not necessary to form it by re-growth. Therefore, highly reliable characteristics without deterioration due to non-radiative recombination can be obtained.

When the super luminescent diode element of the present Example 1 was manufactured, it was 1 at a driving current of 100 mA.
A super luminescent light of 0 mW was obtained.

Al composition ratio x of Ga _{1 -x} Al _x As in the text
It goes without saying that may be changed appropriately.

As an n-type doping method for the n _- type Ga _1-x Al _x As cladding layer 6 and the n-type GaAs contact layer 7, other n-type dopants such as Sn may be used.
By making the temperature of the substrate 1 relatively low and increasing the amount of As flux, it is possible to grow it so as to exhibit n-type conductivity.

(Embodiment 2) FIG. 3 shows a super luminescent diode element of Embodiment 2. In the super luminescent diode element of the present Example 2, a step structure having a slope in the light guiding direction is formed on the surface of the substrate 21 as in the case of the element of the Example 1, and is divided at the position where the slope starts. The groove is formed only in one region and the groove is not formed in the other region. In Figure 3,
Only the cross section of the region where the groove is formed is shown. The types of layers and the stacking order of the regions in which the grooves are not formed are similar to those of the regions in which the grooves are formed, and therefore only the region having the groove structure shown in FIG. 3 will be described below.

In the structure of the device of the second embodiment shown in FIG. 3, a V groove having only two side surfaces having a (111) A plane orientation is formed on the surface of the substrate 21. This V
On the substrate 21 in which the groove is formed, the Si-doped GaAs current confinement layer 22, the Si-doped Ga _1-x Al _x As clad layer 23 (for example, x = 0.50), the p-type Ga _1-x Al _x As clad. Layer 24 (eg x = 0.50), Ga _1-x Al _1-x
As active layer 25 (for example, x = 0.08), n-type Ga _1-x A
l _x As cladding layer 26 (eg x = 0.50) and n
The type GaAs contact layer 27 is formed in this order. These layers are manufactured in the same manner as in the case of manufacturing the device of Example 1.

In the device of Example 2, the Si-doped GaAs current confinement layer 22 and the Si-doped Ga _1-x Al _x As were formed.
Only the region on the slope of the groove in the clad layer 23 (hatched portion in the figure) exhibits p-type conductivity, and this region serves as a current path. In the structure of the device of the second embodiment, the groove shape formed on the substrate 21 is a V groove, and the groove shape of the active layer 25 formed following the V groove is a perfect V groove.
The groove shape is not the groove shape, but the portion immediately above the deepest part of the V groove formed on the substrate 21 is slightly flat.

In the device of the second embodiment having such a structure, the flat part of the active layer 25 serves as a light emitting part, and this part is narrower than that of the device of the first embodiment. realizable.

(Embodiment 3) FIG. 4 shows a super luminescent diode element of Embodiment 3. In the super luminescent diode device of the third embodiment, similarly to the devices of the first and second embodiments described above, a step structure having a slope in the light guiding direction is formed on the surface of the substrate 31, and the slope starts. It has a structure in which a groove is formed only in one region divided by a position and no groove is formed in the other region. In FIG. 4, only the cross section of the region where the groove is formed is shown. The types of layers and the stacking order of the regions in which the grooves are not formed are similar to those of the regions in which the grooves are formed, and therefore only the region having the groove structure shown in FIG. 4 will be described below.

In the structure of the region shown in FIG. 4 of the device of the third embodiment, the groove formed in the substrate 31 is composed of only two side surface portions, and each side surface portion has (111) A and (411) A.
It has two plane orientations. Si on this substrate 31
A doped GaAs current confinement layer 32 is grown and formed.
S corresponding to the (111) A surface of each side surface of the groove of the substrate 31
Only the region of the i-doped GaAs current confinement layer 32 exhibits p-type conductivity, and this portion serves as a current path. (41
1) In the A plane, the ratio of Ga having one bond to the (111) A plane is 2/5, so it is difficult to invert to p-type, and only the growth layer of the (111) A plane has p It exhibits the conductivity of the mold. Si-doped GaAs current confinement layer 3
The configurations of layers after 2 are the same as those in the above-described first and second embodiments.

In the case of the structure of the device of the third embodiment, the current path becomes narrower than that of the first and second embodiments (FIGS. 2 and 3).
The lateral spreading current in the p-type Ga _1-x Al _x As cladding layer 34 can be reduced.

(Embodiment 4) FIG. 5 shows a super luminescent diode element of Embodiment 4. In the superluminescent diode element of the present Example 4, the groove formed on the (100) surface of the p-type GaAs substrate 41 was composed of a bottom surface having a (100) plane orientation and both side surfaces, and each side surface portion was ( The structure has two plane orientations of (111) A and (411) A. The structure of the layer grown and formed on the substrate 41 is the same as that of each of the previous embodiments, but in the device of the fourth embodiment, the Si-doped layer corresponding to the (111) A surface of the side surface of the groove of the substrate is doped. GaAs current confinement layer 42 and Si-doped G
a _1-x Al _x As clad layer 43 (for example, x = 0.50)
The region (hatched portion in the figure) shows p-type conductivity.

Further, since the flat portion of the active layer 45, which becomes the light emitting portion, is grown and formed on the (100) plane, and this portion becomes a growth layer having excellent crystallinity, compared with Examples 2 and 3, (10
Since it grows on the flat portion of the (0) plane and emits light in the crystal layer of the (100) plane, the crystallinity is excellent.
Narrow as usual.

[0058]

In the superluminescent diode device of the present invention, a step structure having a slope in the light guiding direction is formed on the substrate surface, and the active layer in the region corresponding to the slope is bent. Therefore, the light guided through the active layer is spread and radiated to the non-current injection part. Since the active layer on the slope is thinly laminated, light is hardly guided, effective reflectance can be sufficiently reduced, and laser oscillation can be suppressed.

Since the non-current injection part does not absorb the irradiation light, it is possible to obtain high-output superluminescent light.

The method for manufacturing a super luminescent diode element of the present invention uses the plane orientation dependence of the growth rate of MBE growth to bend the active layer by forming a step and to form a thin layered structure. Can be grown, a window structure having a larger forbidden band width than the active layer can be easily formed, and Ga _{1 -x} Al _x A having a large Al composition as in the conventional example
A good regrowth interface is obtained without the need for a regrowth step on the s layer. Non-radiative recombination does not occur. Since the non-current injection part can be easily manufactured, ineffective heat generation and end face destruction do not occur, and high reliability can be realized with low current operation. High yield,
It can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a manufacturing process of an element according to Example 1 of the present invention.

FIG. 2 shows a cross section taken along line LL and line MM in FIG. A shows the cross section along the line LL, and B shows the cross section along the line MM.

FIG. 3 is a diagram showing an element of Example 2;

FIG. 4 is a diagram showing an element of Example 3;

FIG. 5 is a diagram showing an element of Example 4;

FIG. 6 is a diagram showing a conventional example.

[Explanation of symbols]

1 Substrate 2 Si Dove GaAs Current Constriction Layer 3 Si Dove Ga _1-x Al _x As Cladding Layer 4 p-type Ga _1-x Al _x As Cladding Layer 5 Ga _1-x Al _1-x As Active Layer 6 n-type Ga _{1 -x} Al _x As clad layer 7 n-type GaAs contact layer 11 n-type electrode 12 p-type electrode A excitation part B non-current injection part 21 substrate 22 Si-doped GaAs current constriction layer 23 Si-doped Ga _1-x Al _x As clad layer 24 p-type Ga _1-x Al _x As clad layer 25 Ga _1-x Al _1-x As active layer 26 n-type Ga _1-x Al _x As clad layer 27 n-type GaAs contact layer 211 n-type electrode 212 p-type electrode 31 substrate 32 Si-doped GaAs current confinement layer 34 p-type Ga _1-x Al _x As clad layer 35 Ga _1-x Al _1-x As active layer 36 n-type Ga _1-x Al _x As clad layer 37 n-type GaAs Contact layer 311 n-type electrode 312 p-type electrode 41 p-type GaAs substrate 42 Si-doped GaAs current confinement layer 43 Si-doped Ga _1-x Al _x As clad layer 44 p-type Ga _1-x Al _x As clad layer 45 Ga _{1- x} Al _1-x As active layer 46 n-type Ga _1-x Al _x As clad layer 47 n-type GaAs contact layer 411 n-type electrode 412 p-type electrode

Claims (4)

[Claims] 1. On a semiconductor substrate having a step structure having a slope in the light guiding direction, both sides of an active layer including at least a first semiconductor layer have a band gap larger than that of the first semiconductor layer. In a superluminescent diode element having a light emitting laminated portion sandwiched between a large second semiconductor layer and a third semiconductor layer having a band gap larger than that of the first semiconductor layer, The laminated portion is thinly laminated on the slope of the step structure of the semiconductor substrate, and the optical waveguide of the light emitting laminated portion is formed by a groove having a bottom surface portion and both side surface portions, and each side surface portion is one or more. And a growth layer on the one or more plane orientations exhibits p-type conductivity. 2. The super luminescent diode element according to claim 1, wherein the bottom surface portion has a plane orientation of (100). 3. A step of forming a step structure having an inclined surface in the light guiding direction on a (100) plane of a GaAs substrate, and forming a groove having a bottom surface portion and both side surface portions on the substrate. A step of forming the side surface portion to have one or more plane orientations, and a growth layer on the one or more plane orientations of the trenches having p-type conductivity on the substrate having the trenches. Si-doped GaA
A step of growing either the s layer or the Si-doped AlGaAs layer by a molecular beam epitaxy method, and both sides of the active layer including the first semiconductor layer have a band gap larger than that of the first semiconductor layer. A light emitting laminated portion sandwiched between a second semiconductor layer and a third semiconductor layer having a forbidden band width larger than that of the first semiconductor layer is grown on the slope of the step structure on the semiconductor substrate. A method of manufacturing a super luminescent diode element, the method including: 4. The method for manufacturing a super luminescent diode element according to claim 3, wherein the bottom surface of the groove is formed so as to have a (100) plane orientation.