JPH11121874A - Semiconductor light emitting device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light emitting device of high reliability and a manufacturing method, wherein acceptor impurities can be restrained from being diffused into the active layer even when a P-type semiconductor layer is formed or provided adjacent to the side of an active layer after the side face of the active layer is exposed to the outside in a manufacturing process. SOLUTION: A stripe composed of an N-type Alx1 Ga1-x1 As clad layer 2, an Alx2 Ga1-x2 As active layer 3, a P-type Alx1 Ga1-x1 As clad layer 4, and a P-type GaAs cap layer 5 which are successively laminated is provided on an N-type GaAs substrate 1 of (100) plane orientation extending in a [011] direction, and both the sides of the stripe are filled up with a P-type Alx1 Ga1-x1 As buried layer 8, an N-type Alx1 Ga1-x1 As buried layer 9, and a P-type GaAs layer 10. The side of the stripe is a 111} B plane 6, and an Se atomic layer 7 serving as an acceptor impurity diffusion preventing layer is provided to the side of the stripe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor light emitting device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a buried heterojunction (Buried Heterostructure,
A semiconductor laser having a BH) structure is known. FIG.
It is sectional drawing which shows the AlGaAs type semiconductor laser of the conventional BH structure.

That is, as shown in FIG. 17, in this conventional AlGaAs semiconductor laser having a BH structure,
On an n-type GaAs substrate 101, an n-type Al _x1 Ga _1-x1 As
A clad layer 102, an Al _x2 Ga _1-x2 As active layer 103,
p-type Al _x1 Ga _1-x1 As clad layer 104 and p-type G
The aAs cap layer 105 is provided by being sequentially laminated. Here, the n-type Al _x1 Ga _1-x1 As clad layer 102
And Al of the p-type Al _x1 Ga _1-x1 As cladding layer 104
The composition ratio x1 is the same as that of the Al _x2 Ga _{1 -x2} As active layer 103.
It is larger than the composition ratio x2. For example, x1 = 0.45 and x2 = 0.14 for each example. n-type Al
_x1 Ga _1-x1 As clad layer 102, Al _x2 Ga _1-x2 As
Active layer 103, p-type Al _x1 Ga _1-x1 As clad layer 10
The 4 and p-type GaAs cap layers 105 have a stripe shape of a predetermined width extending in one direction.

[0004] The n-type G at both sides of the stripe portion
On the aAs substrate 101, a p-type Al _x1 Ga _1-x1 As buried layer 106 and an n-type Al _x1 Ga _1-x1 As buried layer 10
7 and a p-type GaAs cap layer 108 are sequentially laminated, and a current confinement structure is formed by an npnp thyristor structure. In this case, since x1> x2, the p-type Al _x1 Ga _1-x1 As buried layer 106 and n
The type Al _x1 Ga _1-x1 As buried layer 107 is made of Al _x2 Ga
_It has a larger forbidden band width and a lower refractive index than the _1-x2 As active layer 103. From the viewpoint of satisfactorily confining the current, the interface between the p-type Al _x1 Ga _1-x1 As buried layer 106 and the n-type Al _x1 Ga _1-x1 As buried layer 107 on the side surface of the stripe portion is Al _x2 Ga _{1 -x2} As is located at a portion corresponding to the active layer 103, _{thereby forming} p-type Al _x1 Ga _1-x1 As
The buried layer 106 and the p-type Al _x1 Ga _1-x1 As clad layer 104 are separated from each other, and the n-type Al _x1 Ga _1-x1 As buried layer 107 and the n-type Al _x1 Ga _1-x1 As clad layer 1
02 are separated from each other.

A p-side electrode 109 such as a Ti / Pt / Au electrode is provided on the p-type GaAs cap layer 105 and the p-type GaAs cap layer 108, and AuGe / Ni is provided on the back surface of the n-type GaAs substrate 101. An n-side electrode 110 such as a / Au electrode is provided.

In this conventional AlGaAs semiconductor laser having a BH structure, an n-type Al _x1 Ga _1-x1 As cladding layer 102 and an n-type Al _x1 Ga _1-x1 As buried layer 10 are used.
7 is doped with Se as a donor impurity, while
p-type Al _x1 Ga _1-x1 As clad layer 104, p-type GaAs
The s cap layer 105, the p-type Al _x1 Ga _1-x1 As buried layer 106 and the p-type GaAs cap layer 108 are doped with Zn as an acceptor impurity.

Next, the above-mentioned conventional BH-structured AlGaAs
A method for manufacturing an s-based semiconductor laser will be described.

First, as shown in FIG. 18, n-type GaAs
On a substrate 101, an n-type Al _x1 Ga _1-x1 As clad layer 1
02, Al _x2 Ga _1-x2 As active layer 103, p-type Al _x1 G
a _1-x1 As clad layer 104 and p-type GaAs cap layer 105 are formed, for example, by metal organic chemical vapor deposition (MOCV).
It grows sequentially by the method D).

Next, as shown in FIG.
An insulating film such as a SiN film or a SiO ₂ film is formed on the cap layer 105 by, for example, a CVD method, and is patterned by etching to form a striped mask 111 having a predetermined width.

Next, as shown in FIG.
Is used as an etching mask until the n-type GaAs substrate 101 is exposed by a wet etching method or a dry etching method to form a p-type GaAs cap layer 105, a p-type Al _x1 Ga _1-x1 As clad layer 104,
Al _x2 Ga _1-x2 As active layer 103 and n-type Al _x1 Ga
_{The 1-x1} As clad layer 102 is patterned into a stripe shape having a predetermined width extending in one direction.

Next, as shown in FIG.
Is used as a growth mask, a p-type Al _x1 Ga _1-x1 As buried layer 106, an n-type Al _x1 Ga _1-x1 As buried layer 107 and a p-type GaAs cap layer 108 are sequentially grown to fill both sides of the stripe portion. .

Next, the mask 111 is removed by etching.
After planarizing the surface of the p-type GaAs cap layer 108,
As shown in FIG. 17, the p-side electrode 109 is formed on the p-type GaAs cap layers 105 and 108 by the vacuum evaporation method or the sputtering method, and the n-side electrode 110 is formed on the back surface of the n-type GaAs substrate 101.

As described above, the intended conventional AlGaAs semiconductor laser having the BH structure is manufactured.

In this conventional AlGaAs semiconductor laser having a BH structure, the Al _x2 Ga _{1 -x2} As active layer 103 is used.
And n-type Al _x1 Ga _1-x1 As clad layer 102 and p-type Al
_The double hetero structure sandwiched between the _x1 Ga1 _-x1 As cladding layer 104 has a stripe shape with a predetermined width, and forms a narrow active region. The p-type Al _x1 Ga _1-x1 As buried layer 10 is formed on both sides of the stripe portion.
6. n-type Al _x1 Ga _1-x1 As buried layer 107 and p-type
Since the type GaAs cap layer 108 is buried and a current constriction structure including an npnp thyristor structure is formed, current flows only in the stripe portion (active region). The p-type Al _x1 Ga _1-x1 As buried layer 106 having a larger forbidden band width and a lower refractive index and the n-type Al _x1 are formed on both sides of the Al _x2 Ga _1-x2 As active layer 103.
Since the Ga _1-x1 As buried layer 107 is provided, a step-like refractive index distribution having a high refractive index in the stripe portion and a low refractive index on both sides thereof is formed in the lateral direction, and Al _x2 Ga ₁ Light from the _-x2As active layer 103 is confined by this step-like refractive index distribution. In this conventional AlGaAs semiconductor laser having a BH structure, the threshold of laser oscillation is reduced by confining current and confining light as described above.

[0015]

However, the semiconductor laser having the BH structure according to the prior art has the following problems.

That is, the above-mentioned conventional BH-structured AlG
In an aAs-based semiconductor laser, an n-type Al
_x1 Ga _1-x1 As clad layer 102, Al _x2 Ga _1-x2 As
Active layer 103, p-type Al _x1 Ga _1-x1 As clad layer 10
4 and the p-type GaAs cap layer 105 are patterned into a stripe shape. As a result, the side surfaces of the Al _x2 Ga _1-x2 As active layer 103 are exposed to the outside. In this state, p-type Al _{Since the x1} Ga _1-x1 As buried layer 106 is grown, the p-type Al _x1 Ga _1-x1 As
There is a problem that Zn used as an acceptor impurity in the buried layer 106 diffuses into the Al _x2 Ga _{1 -x2} As active layer 103 through the side surface thereof. Also,
The p-type Al _x1 Ga _1-x1 As buried layer 106 is made of Al _x2 G
by being arranged close to the side of a _1-x2 As active layer 103, even after the growth of the p-type Al _x1 Ga _1-x1 As buried layer 106, a p-type Al _x1 Ga _1-x1 As buried layer 106 Introduced Zn is similarly Al _x2 Ga _1-x2 A
There is also a problem that it diffuses into the s active layer 103.

[0017] Such diffusion of Zn into the active layer causes a reduction in the life of the element, which is a factor of lowering the reliability.

As a countermeasure, it is conceivable to use Mg, which has a small diffusion coefficient and forms a shallow acceptor level, instead of Zn as the acceptor impurity.
Since g has a large segregation coefficient, problems arise in controllability of carrier concentration and uniformity of in-plane distribution.

The above-mentioned problem of the diffusion of Zn into the active layer is caused by, for example, SDH (Separatd Double Heterostruct).
ure) structure of a semiconductor laser (for example, see JP-A-2-652).
No. 88), the same can occur in other semiconductor lasers having a buried structure.

Accordingly, it is an object of the present invention to provide a semiconductor light emitting device capable of suppressing diffusion of acceptor impurities into an active layer and obtaining high reliability, and a method of manufacturing the same.

[0021]

Means for Solving the Problems The present inventor has conducted intensive studies in order to solve the above-mentioned problems of the prior art. The outline is described below.

In general, a zinc-blende type crystal structure III-
It is known that Zn has a large diffusion coefficient in group V compound semiconductors. Here, the state of diffusion of Zn in AlGaAs will be described in comparison with the state of diffusion of Se. Here, an AlGaAs layer is grown on a GaAs substrate. At this time, first, the AlGaAs layer is grown in an undoped state, and then a sample grown while supplying a certain amount of impurity material is obtained by using Zn as an impurity. When,
The samples using Se were manufactured, and the profiles of the impurity concentrations in the depth direction of these samples were obtained by SIMS.
(Secondary ion mass spectrometry) was measured. FIG.
FIG. 23 is a graph showing a measurement result of a sample using Se as an impurity, and FIG. 23 is a graph showing a measurement result of a sample using Zn as an impurity. 22 and 23, the horizontal axis represents the depth from the sample surface, and the vertical axis represents the impurity concentration.

A comparison between FIG. 22 and FIG. 23 shows that in the sample using Se as an impurity, as shown in FIG.
The diffusion of Se is hardly observed on the side of the undoped region when viewed from the position where the supply of the raw material is started, and the boundary between the region doped with Se and the undoped region is clear. As shown in FIG. 23, in the sample using Zn, Zn diffuses largely toward the undoped region when viewed from the position where the supply of the Zn raw material is started, and the boundary between the Zn-doped region and the undoped region is loose. You can see that it is.

Therefore, an AlGaAs layer is first grown on a GaAs substrate in a state of being doped with Se, and then the supply of Se material is stopped and the AlGaAs layer is grown in an undoped state for a predetermined period.
Further, after that, the supply of the Zn raw material was started, and a sample grown in a state of being doped with Zn was prepared, and the profile of the impurity concentration in the depth direction of the sample was measured by the SIMS method. FIG. 24 is a graph showing the measurement results. In FIG. 24, the horizontal axis indicates the depth from the sample surface, and the vertical axis indicates the impurity concentration.

As shown in FIG. 24, A on a GaAs substrate
When growing an lGaAs layer, the impurity source is switched to form an AlGaAs layer doped with Se, an undoped AlGaAs layer, and an AlGaAs layer doped with Zn.
In the case of this sample in which layers were sequentially laminated, Se
The diffusion from the position where the supply of the source material is stopped to the side of the undoped region is hardly observed, and only Zn diffuses from the position where the supply of the Zn source is started to the side of the undoped region.
It can be seen that this Zn piles up greatly in the portion where Se atoms are present, and does not diffuse further.

From this, it is found that Se is present near the side surface of the active layer.
It is considered that the presence of atoms is an effective means for suppressing the diffusion of Zn. Note that Zn and Se
Are examples of an acceptor impurity and a donor impurity in a group III-V compound semiconductor, respectively, and it is considered that the same can be said for other combinations of acceptor impurities and donor impurities.

The present invention has been devised based on the above study.

That is, the first invention of the present invention has a stripe portion having a structure in which an active layer is sandwiched between a p-type cladding layer and an n-type cladding layer, and a p-type semiconductor layer is formed on both sides of the stripe portion. An active layer, a p-type cladding layer, an n-type cladding layer, and a semiconductor layer including a p-type semiconductor layer and an n-type semiconductor layer are embedded with a semiconductor layer including an n-type semiconductor layer. In a semiconductor light emitting device made of a Group V compound semiconductor, a diffusion blocking layer for acceptor impurities of a p-type semiconductor layer and / or a p-type cladding layer is provided at least in a portion corresponding to a side surface of an active layer among side surfaces of a stripe portion, Further, the diffusion blocking layer is made of a group III-V compound semiconductor having a zinc-blende-type crystal structure into which a donor impurity is introduced, or a donor impurity.

According to a second aspect of the present invention, there is provided a stripe portion having a structure in which an active layer is sandwiched between a p-type clad layer and an n-type clad layer, and a p-type semiconductor layer and an n-type A semiconductor layer including a semiconductor layer and an active layer, a p-type cladding layer, an n-type cladding layer, and a semiconductor layer including a p-type semiconductor layer and an n-type semiconductor layer. A p-type cladding layer and / or a diffusion blocking layer for acceptor impurities of the p-type semiconductor layer is provided on at least a portion of the side surface of the stripe portion corresponding to the side surface of the active layer, and the diffusion blocking layer is formed of a compound semiconductor. A method for manufacturing a group III-V compound semiconductor having a zinc-blende-type crystal structure into which a donor impurity is introduced or a semiconductor light emitting device comprising a donor impurity, wherein the donor impurity is formed on a side surface of the stripe portion. A diffusion blocking layer is formed by adsorption, or an n-type semiconductor layer is formed so as to cover at least a portion corresponding to the side surface of the active layer among the side surfaces of the stripe portion. A diffusion blocking layer is formed by selectively introducing a donor impurity into an n-type semiconductor layer.

In the present invention, the same donor impurity as that of the n-type semiconductor layer and / or the n-type cladding layer is preferably used as the donor impurity introduced into the diffusion blocking layer. The acceptor impurity is typically Z
n is used, and Se is typically used as the donor impurity.

In the present invention, a diffusion blocking layer comprising a group III-V compound semiconductor having a zinc-blende type crystal structure into which a donor impurity is introduced or a donor impurity is further provided between the active layer and the p-type cladding layer. It may be provided. At this time, the thickness of the diffusion blocking layer is selected so as not to hinder the current injection. When the diffusion blocking layer is made of a group III-V compound semiconductor having a zinc-blende-type crystal structure into which donor impurities are introduced, the forbidden body width is set to be larger than that of the active layer.

In the present invention, the side surface of the stripe portion is preferably formed of a {111} B plane or a crystal plane which is off by a predetermined angle from the {111} B plane. This is for the following reasons.

That is, III of the zinc-blende type crystal structure
In a -V group compound semiconductor, the state of incorporation and adsorption of impurities has crystal plane dependence. Here, FIG. 25 shows that a GaAs substrate having a different crystal plane is doped with Se-doped Ga.
When the As layer was grown, the Se concentration in the GaAs layer was S
The result measured by the IMS method is shown. In FIG.
The horizontal axis shows the inclination angle from the (100) plane, and the vertical axis shows S
The Se concentration in the GaAs layer doped with e is (10
The value when the density on the 0) plane is normalized to 1 is shown.

In this case, as shown in FIG.
It can be seen that in the GaAs layer grown on the substrate, when the GaAs substrate has a {111} B crystal plane, the Se atom concentration is higher than when the GaAs substrate has a {100} plane or a {111} A plane.

Therefore, in order to easily form the diffusion element layer on the side surface of the stripe portion, it can be said that it is effective to make the side surface of the stripe portion a {111} B plane or a crystal plane in the vicinity thereof.

As described above, the side surface of the stripe portion is {111}.
This is because it is preferable to set the crystal plane to be off by a predetermined angle from the B plane or {111} B plane. The stripe portion may be formed by etching a structure in which an active layer is sandwiched between a p-type clad layer and an n-type clad layer, or alternatively, the active layer may be formed by p-type clad layer and n-type clad layer. It may be formed in the process of forming a structure sandwiched between the mold cladding layers.

According to the present invention having the above-described structure, at least a portion of the side surface of the stripe portion corresponding to the side surface of the active layer has a zinc-blende type III-V crystal structure in which a donor impurity is introduced. By providing a diffusion blocking layer of an acceptor impurity of a p-type semiconductor layer and / or a p-type cladding layer made of a compound semiconductor or a donor impurity, a p-type semiconductor layer is exposed after a side surface of the active layer is exposed to the outside in a manufacturing process. (Here, mainly a p-type semiconductor layer of the semiconductor layers embedded on both sides of the stripe portion, but in some cases, also includes a p-type cladding layer) Even when the p-type semiconductor layer is provided close to the side surface of the active layer, diffusion of acceptor impurities into the active layer can be suppressed.

[0038]

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

First, a first embodiment of the present invention will be described. FIG. 1 is a sectional view showing an AlGaAs-based semiconductor laser having a BH structure according to the first embodiment.

As shown in FIG. 1, in the AlGaAs-based semiconductor laser having the BH structure according to the first embodiment, for example, an n-type Ga
As substrate 1 is used. On this n-type GaAs substrate 1,
n-type Al _x1 Ga _1-x1 As clad layer 2, Al _x2 Ga _1-x2
An As active layer 3, a p-type Al _x1 Ga _1-x1 As clad layer 4 and a p-type GaAs cap layer 5 are sequentially laminated. Here, the n-type Al _x1 Ga _1-x1 As clad layer 2
And the Al composition ratio x1 of the p-type Al _x1 Ga _1-x1 As clad layer 4 is the Al composition ratio x of the Al _x2 Ga _1-x2 As active layer 3.
2 and, for example, x1
= 0.45 and x2 = 0.14.

N-type Al _x1 Ga _1-x1 As clad layer 2, A
The l _x2 Ga _1-x2 As active layer 3, the p-type Al _x1 Ga _1-x1 As clad layer 4 and the p-type GaAs cap layer 5 are formed as [01
1] It has a stripe shape of a predetermined width extending in the direction. In this case, the side surface of the stripe portion is composed of the {111} B surface 6. Reference numeral 7 denotes a Se atomic layer as a diffusion blocking layer for acceptor impurities. This Se atomic layer 7 is made of n-type Al
_The stripe portion of the _x1 Ga1 _-x1 As clad layer 2, the _Alx2 Ga1 _-x2 As active layer 3, the p-type _Alx1 Ga1 _-x1 As clad layer 4, and the p-type GaAs cap layer 5 are covered with the stripe portions. It is provided near the surface layer on the side surface. In this case, as described later, the Se atom layer 7 is formed such that the Se atoms adsorbed on the side surface of the stripe portion are composed of the n-type Al _x1 Ga _{1 -x1} As clad layer 2 and the Al _x2 Ga _{1 -x2} As active layer 3. , P-type Al _x1 Ga
_1-x1 As clad layer 4 and p-type GaAs cap layer 5
It is formed by being introduced inside. The thickness of the Se atomic layer 7 is, for example, 50 nm or less, and
The concentration is, for example, 5 × 10 ¹⁷ / cm ³ to 1 × 10 ¹⁸ / cm ³
It is about.

N-type G at both sides of the stripe portion
On the aAs substrate 1, a p-type Al _x1 Ga _1-x1 As buried layer 8, an n-type Al _x1 Ga _1-x1 As buried layer 9 and a p-type GaAs cap layer 10 are sequentially laminated and provided.
A current confinement structure is formed by an np thyristor structure. In this case, since x1> x2, p-type Al _x1 G
a _1-x1 As buried layer 8 and n-type Al _x1 Ga _1-x1 As
The buried layer 9 has a larger forbidden band width and a lower refractive index than the Al _x2 Ga _1-x2 As active layer 3. Where {111} B
The epitaxial growth rate on the surface 6 is smaller than that of the (100) plane, and the crystal growth on the {111} B surface 6 stops apparently until the growth from the n-type GaAs substrate 1 progresses. _-Type Al _x1 Ga _1-x1 As buried layer 8, n-type Al _x1 Ga _1-x1 As buried layer 9, and n-type G
The aAs cap layer 10 is formed in the illustrated shape.
Also, p-type Al _x1 Ga on the side surface of the stripe portion
The interface between the _1-x1 As buried layer 8 and the n-type Al _x1 Ga _1-x1 As buried layer 9 is located at a portion corresponding to the Al _x2 Ga _1-x2 As active layer 3.

The p-type GaAs cap layer 5 and the p-type Ga
A p-side electrode 11 such as a Ti / Pt / Au electrode is provided on the As cap layer 10, and an n-side electrode 12 such as an AuGe / Ni / Au electrode is provided on the back surface of the n-type GaAs substrate 1. I have.

In the AlGaAs semiconductor laser having the BH structure, the n-type Al _x1 Ga _1-x1 As clad layer 2 and the n-type Al _x1 Ga _1-x1 As buried layer 9 are doped with Se as a donor impurity. , P-type Al _x1 Ga
_1-x1 As clad layer 4, p-type GaAs cap layer 5, p
Al _x1 Ga _1-x1 As buried layer 8 and p-type GaAs
The cap layer 10 is doped with Zn as an acceptor impurity.

Next, a method of manufacturing the AlGaAs semiconductor laser having the BH structure according to the first embodiment having the above-described structure will be described. Here, the semiconductor layer constituting this BH-structured AlGaAs-based semiconductor laser is
For example, it is formed by the MOCVD method. At this time, III-
As the raw material for V compound semiconductor, trimethyl aluminum (TMA), trimethyl gallium (TMG), arsine (AsH ₃₎ is used. As a raw material of a donor impurity for example H ₂ Se, as the material of an acceptor impurity such as dimethyl Zuinku ( DMZ).

First, as shown in FIG. 2, an n-type GaAs substrate 1 having a (100) plane orientation is formed on a n-type GaAs substrate 1 by MOCVD.
Type Al _x1 Ga _1-x1 As clad layer 2, Al _x2 Ga _1-x2 A
An s active layer 3, a p-type Al _x1 Ga _1-x1 As clad layer 4 and a p-type GaAs cap layer 5 are sequentially grown.

Next, the n-type GaAs substrate 1 is once taken out of the growth apparatus, and as shown in FIG. 3, an insulating film such as a SiN _x film or a SiO ₂ film is formed on the entire surface of the p-type GaAs cap layer 5 by, eg, CVD. A film is formed, and the film is patterned by etching to form a stripe-shaped mask 13 having a predetermined width extending in the [011] direction.

Next, as shown in FIG. 4, the mask 13 is used as an etching mask, for example, H ₂ as an etching solution.
A mixed solution of SO ₄ , H ₂ O ₂ and H ₂ O (the mixing ratio is, for example, H ₂ SO ₄ : H ₂ O ₂ : H ₂ O = 3: 2:
N-type GaAs by wet etching using 1)
Etching is performed until the s substrate 1 is exposed. Thereby, the p-type GaAs cap layer 5 and the p-type Al _x1 Ga _1-x1 A
s cladding layer 4, Al _x2 Ga _1-x2 As active layer 3 and n
The mold Al _x1 Ga _1-x1 As clad layer 2 is patterned into a stripe shape having a predetermined width extending in the [011] direction. At this time, the side surface of the stripe portion is {111} B
Surface 6

Next, the n-type GaAs substrate 1 is carried into the growth apparatus again, and as shown in FIG. 5, H ₂ Se gas used as a source material of the donor impurity is thermally decomposed,
Se atoms 14 are adsorbed on the entire surface including the side surfaces of the stripe portion. Thereafter, as shown in FIG. 6, by heating the substrate,
Se atoms 14 adsorbed on the side surface of the stripe portion are n-type A
l _x1 Ga _1-x1 As clad layer 2, Al _x2 Ga _1-x2 As active layer 3, p-type Al _x1 Ga _1-x1 As clad layer 4 and p
By being introduced into the type GaAs cap layer 5, the Se atomic layer 7 is selectively formed near the surface layer on the side surface of the stripe portion. In this case, the side of the stripe portion is # 11
Since the 1｝ B plane 6 is provided, and Se atoms are more easily introduced than other crystal planes, the Se atomic layer 7 is selectively formed on the side surface of the stripe portion. Note that the substrate heating at this time can also be used as the substrate heating during the second crystal growth for forming the p-type Al _x1 Ga _1-x1 As buried layer 8 and the like.

Next, as shown in FIG. 7, using the mask 13 as a growth mask, a p-type Al _x1 Ga _1-x1 As buried layer 8, an n-type Al _x1 Ga _1-x1 As buried layer 9 and a p-type G
The aAs cap layer 10 is sequentially grown to fill the portions on both sides of the stripe portion.

Next, after the mask 13 is removed by etching, the surface of the p-type GaAs cap layer 10 is smoothed, and thereafter, as shown in FIG. 1, the p-type GaAs cap layer 5 is formed by vacuum evaporation or sputtering. A p-side electrode 11 is formed on 10, and an n-side electrode 12 is formed on the back surface of the n-type GaAs substrate 1.

As described above, the desired BH-structured AlG
An aAs-based semiconductor laser is manufactured.

As described above, according to the first embodiment, since the side surface of the stripe portion is composed of the {111} B surface 6, the side surface of the stripe portion is formed of Se atoms as a diffusion blocking layer for acceptor impurities. The layer 7 can be easily formed. The Se atomic layer 7 allows Al _x2
The side surface of the Ga _1-x2 As active layer 3 is covered and this Se 1
By forming the atomic layer 7 before growing the p-type Al _x1 Ga _1-x1 As buried layer 8, the following advantages can be obtained.

That is, during the growth of the p-type Al _x1 Ga _{1 -x1} As buried layer 8, the Se atomic layer 7 serves as a barrier against the intrusion of Zn, so that the side surface of the Al _x2 Ga _{1 -x2} As active layer 3 is formed. Can prevent Zn from diffusing into the inside thereof. Also, a p-type Al _x1 Ga _1-x1 As buried layer 8
Is provided adjacent to the side surface of the Al _x2 Ga _{1 -x2} As active layer 3, and the p-type Al _x1 Ga _{1 -x1} As buried layer 8
Even when n diffuses, Al _x2 Ga _1-x2 A
Zn diffused in the direction of the s active layer 3 is Al _x2 Ga
Before reaching the _1-x2 As active layer 3, pile-up occurs at the Se atomic layer 7, so that Zn diffusion into the Al _x2 Ga _1-x2 As active layer 3 is suppressed.

Therefore, according to the first embodiment, Z is _{introduced into the} Al _x2 Ga _{1 -x2} As active layer 3 during and after the growth of the p-type Al _x1 Ga _{1 -x1} As buried layer 8.
The diffusion of n can be effectively suppressed, whereby the life of the element can be extended, and a highly reliable AlGaAs-based semiconductor laser having a BH structure can be realized.

Next, a second embodiment of the present invention will be described. FIG. 8 is a sectional view showing an AlGaAs-based semiconductor laser having a BH structure according to the second embodiment.

That is, the BH according to the second embodiment
In an AlGaAs-based semiconductor laser having a structure, as shown in FIG. 8, a (100) plane oriented p-type Ga
An As substrate 21 is used. On this p-type GaAs substrate 21, a p-type Al _x1 Ga _1-x1 As clad layer 22 and an Al _x2 G
An a _1-x2 As active layer 23, an n-type Al _x1 Ga _1-x1 As clad layer 24 and an n-type GaAs cap layer 25 are sequentially laminated. Here, the Al composition ratio x1 of the p-type Al _x1 Ga _1-x1 As clad layer 22 and the n-type Al _x1 Ga _1-x1 As clad layer 24 is the same as that of the Al _x2 Ga _1-x2 As active layer 3.
It is larger than the composition ratio x2. For example, x1 = 0.45 and x2 = 0.14 for each example.

The p-type Al _x1 Ga _1-x1 As clad layer 22,
Al _x2 Ga _1-x2 As active layer 23, n-type Al _x1 Ga _1-x1 A
s cladding layer 24 and n-type GaAs cap layer 25
Has a stripe shape of a predetermined width extending in the [011] direction. In this case, the side of this stripe portion is # 11
1｝ B surface 26

P-type GaAs on both sides of the stripe portion
On the substrate 21, an n-type Al _x1 Ga _{1- x1} As buried layer 2
7, p-type Al _x1 Ga _1-x1 As buried layer 28 and n-type GaAs cap layer 29 is provided by sequentially stacking, thereby, the current confinement structure by a thyristor structure of pnpn is formed. In this case, since x1> x2, the n-type Al _x1 Ga _1-x1 As buried layer 27 and the p-type Al _x1 Ga _1-x1 As buried layer 28 are Al _x2 Ga _1-x2
The forbidden body width is larger than that of the As active layer 23 and the refractive index is low. Further, in the portion on the side surface of the stripe portion, the n-type Al _x1 Ga _1-x1 As buried layer 27 has the p-type Al _x1 Ga
_The p-type Al _x1 Ga is provided to a position covering the side surfaces of the _1-x1 As clad layer 22 and the Al _x2 Ga _1-x2 As active layer 23.
_{The 1-x1} As clad layer 29 is provided to a position covering the side surface of the n-type Al _x1 Ga _1-x1 As clad layer 24.

Reference numeral 30 denotes a Se atomic layer as a diffusion blocking layer for acceptor impurities. In this case, the Se atomic layer 30 covers the side surfaces of the p-type Al _x1 Ga _1-x1 As clad layer 22 and the Al _x2 Ga _1-x2 As active layer 23.
The n-type Al _x1 Ga _1-x1 As buried layer 27 is provided on a portion on the side surface of the stripe portion. As described later, when forming the n-type Al _x1 Ga _{1 -x1} As buried layer 27, the Se atomic layer 30 is selectively formed on a portion on the side surface of the stripe portion composed of the {111} B plane 26. By introducing atoms (more Se atoms than other portions), the n-type Al _x1 Ga _1-x1 As buried layer 27 is selectively formed on a portion on the side surface of the stripe portion. Things.

N-type GaAs cap layer 25 and n-type G
An n-side electrode 31 such as an AuGe / Ni / Au electrode is provided on the aAs cap layer 29, and the p-type GaAs substrate 2
1 is a p-side electrode 3 such as a Ti / Pt / Au electrode
2 are provided.

In the AlGaAs semiconductor laser having the BH structure, the p-type Al _x1 Ga _1-x1 As clad layer 22 and the p-type Al _x1 Ga _1-x1 As buried layer 28 are doped with Zn as an acceptor impurity. , N-type Al
_{The x1} Ga1 _-x1 As clad layer 24, the n-type GaAs cap layer 25, the n-type _Alx1 Ga1 _-x1 As buried layer 27, and the n-type GaAs cap layer 29 are doped with Se as a donor impurity.

Next, a method of manufacturing the AlGaAs semiconductor laser having the BH structure according to the second embodiment will be described.

First, A of the BH structure according to the first embodiment
As in the method of manufacturing an lGaAs semiconductor laser, as shown in FIG.
A p-type Al _x1 Ga _1-x1 As clad layer 22 on a substrate 21;
Al _x2 Ga _1-x2 As active layer 23, n-type Al _x1 Ga _1-x1 A
After sequentially growing the s-cladding layer 24 and the p-type GaAs cap layer 25, on the p-type GaAs cap layer 25,
A stripe-shaped mask 33 having a predetermined width extending in the [011] direction is formed. Using this mask 33 as an etching mask, the p-type GaAs substrate 21 is formed by a wet etching method using a sulfuric acid-hydrogen peroxide-based etchant. Etch until the surface is exposed. Thereby, n-type Ga
As cap layer 25, n-type Al _x1 Ga _1-x1 As clad layer 24, Al _x2 Ga _1-x2 As active layer 23 and p-type Al
_{The x1} Ga1 _-x1 As cladding layer 22 is patterned into a stripe shape having a predetermined width extending in the [011] direction.
At this time, the side surface of this stripe portion is {111} B surface 2
It becomes 6.

Next, as shown in FIG. 10, using the mask 33 as a growth mask, an n-type A
A _{lx1Ga1 -x1As} buried layer 27 is grown. At this time, more Se atoms are introduced into the portion of the n-type Al _x1 Ga _1-x1 As buried layer 27 on the side surface of the stripe portion than in the other portions, so that the Se atom layer is selectively formed in this portion. 30 are formed.

Following the growth of the n-type Al _x1 Ga _1-x1 As buried layer 27, as shown in FIG. 11, the p-type Al _x1 Ga is formed by MOCVD using the mask 33 as a growth mask.
_{A 1-x1} As buried layer 28 and an n-type GaAs cap layer 29 are sequentially grown to fill both sides of the stripe portion.

Next, the mask 33 is removed by etching and n
After smoothing the surface of the type GaAs cap layer 29, FIG.
As shown in FIG. 5, an n-side electrode 31 is formed on the n-type GaAs cap layer 25 and the n-type GaAs cap layer 29 by a vacuum evaporation method or a sputtering method.
A p-side electrode 32 is formed on the back surface of the type GaAs substrate 21.

As described above, the target AlH having the BH structure is obtained.
An aAs-based semiconductor laser is manufactured.

As described above, according to the second embodiment, the n-type Al _x1 Ga _{1 -x1} As buried layer 27 is grown by _{forming the} side surface of the stripe portion from the {111} B surface 26. In addition, the Se atomic layer 30 as a diffusion blocking layer can be selectively and easily formed on a portion of the n-type Al _x1 Ga _1-x1 As buried layer 27 on the side surface of the stripe portion. Then, the side surface of the Al _x1 Ga _1-x1 As active layer 23 is covered with the Se atomic layer 30, and the Se atomic layer 30 is formed before growing the p-type Al _x1 Ga _1-x1 As buried layer 28. By being
Diffusion of Zn into the Al _x2 Ga _1-x2 As active layer 23 during and after the growth of the p-type Al _x1 Ga _1-x1 As buried layer 28 can be suppressed.

Therefore, according to the second embodiment, AlGaAs having a BH structure using a p-type semiconductor substrate is used.
In the system semiconductor laser, the same effects as in the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described. FIG. 12 shows the SDH according to the third embodiment.
It is sectional drawing which shows the AlGaAs semiconductor laser of a structure.

As shown in FIG. 12, A of this SDH structure
In an lGaAs semiconductor laser, (1)
An n-type GaAs substrate 41 having a (00) plane orientation is used, and a main surface of the n-type GaAs substrate 41 is provided with a mesa-shaped projection 41a extending in the [011] direction. n-type GaAs
On the mesa-shaped projection 41a of the substrate 41, n-type Al _x1 Ga
_1-x1 As clad layer 42, Al _x2 Ga _1-x2 As active layer 4
A stripe portion having a double hetero structure in which 3 and p-type Al _x1 Ga _1-x1 As clad layers 44 are sequentially stacked is provided. The stripe portion extends in the extension direction of the mesa-shaped protrusion 41a, that is, the [011] direction, and has a triangular cross section. In this case, the side of the stripe portion is # 1
11 ° B surface 45, both sides of which are p-type Al _x1 Ga
They intersect at the _1-x1 As cladding layer 44. n-type A
l _x1 Ga _1-x1 As clad layer 42, Al _x1 Ga _1-x1 As
Active layer 43 and p-type Al _x1 Ga _1-x1 As clad layer 4
4 is an n-type GaAs substrate 41
Are also provided at the bottom of the mesa (on both sides of the mesa-shaped projection 41a). In this case, the Al _x2 Ga _1-x2 As active layer 43 on the mesa projecting portion 41a, and the Al _x2 Ga _1-x2 As active layer 43 on the mesa bottom and are separated from each other. Also, p-type Al _x1 Ga _1-x1 on the mesa bottom
The As cladding layer 44 is provided on the mesa-shaped protrusion 41a to a position in the middle of the side surface of the n-type Al _x1 Ga _1-x1 As cladding layer.

Reference numeral 46 denotes a Se atomic layer as a diffusion blocking layer for acceptor impurities. In this case, the Se atomic layer 46 is formed on the n-type Al _x1 Ga _1-x1 on the mesa-shaped protrusion 41a.
As cladding layer 42 and Al _x2 Ga _1-x2 As active layer 4
3 is provided on the side surface of the stripe portion so as to cover the side surface. As will be described later, the Se atomic layer 46 is formed on the side surfaces of the n-type Al _x1 Ga _{1 -x1} As clad layer 42 and the Al _x2 Ga _{1 -x2} As active layer 43 on the mesa-shaped projection 41a.
It is formed by adsorbing atoms. This Se atomic layer 46 has a thickness of about several atomic layers.

On the p-type Al _x1 Ga _1-x1 As clad layer 44 on the mesa bottom, the Al _x2 G on the mesa-shaped projection 41a is formed.
a _{1 -x2} As the n-type Al _x1
A Ga _1-x1 As current confinement layer 47 is provided. In this case, since x1> x2, the n-type Al _x1 Ga _1-x1 As current confinement layer 47 has a larger forbidden body width and lower refractive index than the Al _x2 Ga _1-x2 As active layer 43. This n-type Al _x1 Ga
The _1-x1 As current confinement layer 47, a p-type Al _x1 Ga _1-x1 As cladding layer 44 on the mesa projecting portion 41a, a p-type Al _x1 Ga _1-x1 As cladding layer 44 on the mesa bottom together Are separated. Reference numeral 48 denotes a p-type Al _x1 Ga _1-x1 As
3 shows a cladding layer. The p-type Al _x1 Ga _1-x1 As cladding layer 48 is formed so that n-type A
l _x1 Ga _1-x1 As is provided on the current confinement layer 47, and
It is also provided above the p-type Al _x1 Ga _1-x1 As clad layer 44 on the mesa-shaped projection 41a. This p-type Al _x1 G
On the a _1-x1 As clad layer 48, a p-type GaAs cap layer 49 is provided.

On the p-type GaAs cap layer 49, Ti /
A p-side electrode 50 such as a Pt / Au electrode is provided, while an AuGe / Ni /
An n-side electrode 51 such as an Au electrode is provided.

In the AlGaAs semiconductor laser having the SDH structure, the n-type Al _x1 Ga _{1 -x1} As clad layer 42
The n-type Al _x1 Ga _1-x1 As current confinement layer 47 is doped with Se as a donor impurity, while the p-type Al _x1
Ga _1-x1 As cladding layers 44 and 48 and p-type GaAs
The cap layer 49 is doped with Zn as an acceptor impurity.

Next, a method of manufacturing an AlGaAs semiconductor laser having an SDH structure according to the third embodiment will be described.

As shown in FIG. 13, a stripe-shaped resist pattern (not shown) having a predetermined width extending in the [011] direction is formed on an n-type GaAs substrate 41 having a (100) plane orientation. N-type Ga as a mask
By etching the As substrate 41 by, for example, a wet etching method using a sulfuric acid-hydrogen peroxide-based etchant, the mesa-shaped projections 41a are formed. Next, the resist pattern used as the etching mask is removed.

Next, the MOC is placed on the n-type GaAs substrate 41.
By the VD method, the n-type Al _x1 Ga _1-x1 As clad layer 42
And an Al _x2 Ga _1-x2 As active layer 43 are sequentially grown. At this time, the n-type Al _x1
Ga _1-x1 As clad layer 42 and Al _x2 Ga _1-x2 As
The active layer 43 grows while forming a slope composed of the {111} B plane 45 inward from the edge of the mesa-shaped protrusion 41a.

Next, as shown in FIG. 14, the H ₂ Se gas used as the source material of the donor impurity is thermally decomposed to adsorb Se atoms on the entire surface, thereby forming the Se atom layer 46. Here, for simplicity of description, {111}
Although only the Se atomic layer 46 on the B surface 45 is shown, the Se atomic layer 46 actually
It is also formed on the upper surface of the l _x2 Ga _1-x2 As active layer 43 and the like. The Se atomic layer formed on the upper surface of the Al _x2 Ga _1-x2 As active layer 43 has a p-type Al _x1 Ga
_It has a role of suppressing the diffusion of Zn from the _1-x1 As cladding layer 44. Even when the Se atomic layer is formed on the upper surface of the Al _x2 Ga _1-x2 As active layer 43 as described above, the Se atomic layer has a thickness of about several atomic layers and is extremely thin. Does not interfere with the injection.

Next, as shown in FIG. 15, n-type GaAs
On the substrate 41, p-type Al _x1 Ga is formed by MOCVD.
_{A 1-x1} As cladding layer 44 is grown. As a result, a stripe portion is formed on the mesa-shaped projection 41a. In this case, the p-type Al _x1 Ga _1-x1 As on the mesa-shaped protrusion 41a
The width of the clad layer 44 becomes smaller as the growth proceeds, and finally grows to a position where the side surfaces composed of the {111} B planes 45 on both sides intersect. On the other hand, at this time, the p-type Al _x1 Ga _1-x1 As clad layer 44 on the mesa bottom is
The n-type Al _x1 Ga _1-x1 As clad layer 42 on the mesa-shaped projection 41a is grown to a position halfway along the side surface.

Next, n-type Al _x1 Ga
_{A 1-x1} As current confinement layer 47 is grown. In this case, the n-type Al _x1 Ga _1-x1 As current confinement layer 47 is thickened during growth so as to cover a portion corresponding to the side surface of the Al _x2 Ga _1-x2 As active layer 43 on the mesa-shaped projection 41a. Is controlled.
Next, a p-type Al _x1 Ga _1-x1 As clad layer 48 and a p-type GaAs cap layer 49 are sequentially grown by MOCVD. In this case, the p-type Al _x1 Ga _1-x1 As cladding layer 48 has a {111} B
Although it is not grown on the surface 45, it grows over the entire surface including the portion on the {111} B surface 45 as the growth proceeds on another crystal surface. Therefore, this p-type Al _x1 G
The p-type GaAs cap layer 49 on the a _1-x1 As clad layer 48 is also grown on the entire surface.

The steps from the growth of the n-type Al _x1 Ga _1-x1 As clad layer 42 to the growth of the p-type GaAs cap layer 49 are performed in one crystal growth by switching the supplied source gas. .

Next, as shown in FIG. 12, a p-side electrode 50 is formed on the p-type GaAs cap layer 49 by vacuum evaporation or sputtering, and n-type GaAs is formed.
An n-side electrode 51 is formed on the s substrate 41.

As described above, the target SDH structure Al
A GaAs-based semiconductor laser is manufactured.

As described above, according to the third embodiment,
For example, in the process of forming the stripe portion, the mesa-like projection 41a is formed.
N-type Al on top_x1Ga_1-x1As clad layer 42, Al_x2
Ga _1-x2As active layer 43 and p-type Al_x1Ga_1-x1As
In the process of growing the cladding layer 44, each of these layers becomes # 11
1. Growing while forming a slope composed of 1｝ B surface 45a
As a result, the side surface of the stripe portion is composed of {111} B surface 45
As a result, the acceptor is not
Easy formation of Se atomic layer 46 as pure substance diffusion blocking layer
can do. Then, this Se atomic layer 46
Al_x2Ga_1-x2The side surface of the As active layer 43 is covered,
First, this Se atomic layer 46 is made of p-type Al_x1Ga_1-x1Asku
Being formed before growing the lad layer 44.
, P-type Al_x1Ga_1-x1During the growth of the As cladding layer 44
And Al after growth_x2Ga_1-x2In the As active layer 43
The diffusion of Zn into the portion can be suppressed.

Therefore, according to the third embodiment, the same effect as that of the first embodiment can be obtained in the semiconductor laser having the SDH structure using the n-type semiconductor substrate.

Next, a fourth embodiment of the present invention will be described. FIG. 16 shows the SDH according to the fourth embodiment.
It is sectional drawing which shows the AlGaAs semiconductor laser of a structure. AlGaAs of SDH structure according to the fourth embodiment
The s-based semiconductor laser has the opposite conductivity type to the SDH-structured AlGaAs-based semiconductor laser according to the third embodiment.

That is, as shown in FIG.
In an AlGaAs semiconductor laser having an H structure, a p-type GaAs substrate 61 having a (100) plane orientation is used as a substrate, and a mesa-like projection 61a extending in the [011] direction is formed on a main surface of the p-type GaAs substrate 61. Is provided. Reference numeral 62 denotes a p-type Al _x1 Ga _1-x1 As cladding layer, reference numeral 63 denotes an Al _x2 Ga _1-x2 As active layer, and reference numeral 64 denotes an n-type Al _x1 Ga.
_1-x1 As clad layer, reference numeral 65 denotes {111} B plane, reference numeral 66 denotes Se atomic layer, reference numeral 67 denotes p-type Al _x1 Ga _1-x1 As
Reference numeral 68 denotes an n-type Al _x1 Ga _1-x1 As cladding layer, and reference numeral 69 denotes an n-type GaAs cap layer.

In this case, the Se atomic layer 66 is made of p-type Al_x1
Ga_1-x1As clad layer 62, Al _x2Ga_1-x2As activity
Layer 63 and n-type Al_x1Ga_1-x1As clad layer 64
It is provided on the side of the stripe part so as to cover the side,
AuGe / Ni / A on the n-type GaAs cap layer 69
An n-side electrode 70 such as a u-electrode is provided, and p-type GaAs
On the back surface of the substrate 61, a p-side such as a Ti / Pt / Au electrode
An electrode 71 is provided.

The other configuration is similar to that of the third embodiment.
The description is omitted because it is the same as that of the AlGaAs semiconductor laser having the DH structure.

Next, a method of manufacturing an AlGaAs semiconductor laser having an SDH structure according to the fourth embodiment will be described. That is, in the AlGaAs-based semiconductor laser having the SDH structure, the p-type Al _x1 Ga _1-x1 As buried layer 67 has the Al _x2 Ga _1-x2 A on the mesa-shaped protrusion 61a.
Since it is provided so as to cover the side surface of the s active layer 63,
The diffusion of Zn into the Al _x2 Ga _1-x2 As active layer 63 during and after the growth of the p-type Al _x1 Ga _1-x1 As buried layer 67 becomes a problem. Therefore, A of this SDH structure
When manufacturing an lGaAs semiconductor laser, p-type Al
forming an Se atom layer 66 before forming the _x1 Ga _1-x1 As buried layer 67. Specifically, this Se atomic layer 66
During the growth of the n-type Al _x1 Ga _{1 -x1} As clad layer 64, H ₂ Se used as a donor impurity material is thermally decomposed and Se atoms are adsorbed on the side surfaces of the stripe portion. The other points are the same as those of the method for manufacturing the AlGaAs-based semiconductor laser having the SDH structure according to the third embodiment, and thus the description is omitted.

According to the fourth embodiment, the same effect as that of the first embodiment can be obtained in an AlGaAs semiconductor laser having an SDH structure using a p-type semiconductor substrate.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above embodiments, and various modifications based on the technical concept of the present invention are possible. For example, the numerical values, materials, structures, manufacturing processes, and the like described in the embodiments are merely examples, and the present invention is not limited thereto. In the first embodiment, the Se atomic layer 7 as a diffusion blocking layer is
The Se atoms adsorbed on the {111} B surface 6 are n-type Al
_{x 1} Ga ₁ -x ₁ As clad layer 2, Al _{x 2} Ga _{1 -x 2} As active layer 3, p-type Al _{x 1} Ga ₁ -x ₁ As clad layer 4 and p-type GaAs cap layer 5 are formed. However, this Se atomic layer 7 has {111} B
A layer composed of Se atoms adsorbed on the surface 6 (a state in which Se atoms are adsorbed) may be used.

In the first to fourth embodiments,
Between the active layer forming the stripe portion and the p-type cladding layer, as a diffusion blocking layer, Se is doped as a donor impurity and the bandgap is larger than the active layer. An n-type semiconductor layer made of a V compound semiconductor may be provided. The thickness of the n-type semiconductor layer is selected so as not to hinder current injection. Specifically, for example, in the third embodiment, Al _x2 Ga
Another n-type Al _x1 G doped with Se is provided between the _1-x2 As active layer 43 and the p-type Al _x1 Ga _1-x1 As cladding layer 44.
An a _1-x1 As clad layer may be provided. In this case, Zn in the p-type Al _x1 Ga _1-x1 As clad layer 44 is changed to Al _x2
Diffusion through the upper surface of the Ga _1-x2 As active layer 43 into the inside thereof can be effectively suppressed. Also,
In this case, the n-type Al _x1 Ga _1-x1 As cladding layer
After forming the Al _x2 Ga _1-x2 As active layer 43, the p-type Al
_It is formed before forming the _x1 Ga1 _-x1 As clad layer 44, and at this time, the Se atomic layer 46 can be formed at the same time.

In the first and second embodiments, the side surface of the stripe portion is formed of {111} B surface.
The side surface of the stripe portion may be a crystal plane that is off by several degrees from the {111} B plane, specifically, for example, by 0 ° to 5 °.

In the above-described first to fourth embodiments, an optical waveguide layer can be provided if necessary, and the active layer can have a multiple quantum well structure.

Further, in the above-described first to fourth embodiments, the present invention is applied to an AlG having a DH structure and an SDH structure.
Although the description has been given of the case where the present invention is applied to an aAs-based semiconductor laser, the present invention may be applied to an AlGaAs-based light emitting diode as well as an AlGaAs-based semiconductor laser having another buried structure. Further, the present invention relates to the above-described AlGaAs.
-Based semiconductor light emitting devices, other than the zinc-blende-type crystal structure II
The present invention can be applied to other semiconductor light emitting devices using an IV compound semiconductor, for example, an AlGaInP-based semiconductor light emitting device.

[0099]

As described above, according to the present invention, a zinc-blende type crystal structure of a zinc-blende type crystal structure in which a donor impurity is introduced into at least a portion corresponding to the side surface of the active layer among the side surfaces of the stripe portion. By providing a diffusion blocking layer for acceptor impurities in the p-type semiconductor layer and / or the p-type cladding layer, which is made of a group III compound semiconductor or a donor impurity, diffusion of the acceptor impurities into the active layer is effectively suppressed. As a result, the life of the element can be extended, and a highly reliable semiconductor light emitting element can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an AlGaAs-based semiconductor laser having a BH structure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the method for manufacturing the BH-structured AlGaAs-based semiconductor laser according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining the method for manufacturing the AlGaAs semiconductor laser having the BH structure according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view for explaining the method for manufacturing the AlGaAs-based semiconductor laser having the BH structure according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining the method for manufacturing the AlGaAs semiconductor laser having the BH structure according to the first embodiment of the present invention.

FIG. 6 is a sectional view for explaining the method for manufacturing the AlGaAs semiconductor laser having the BH structure according to the first embodiment of the present invention.

FIG. 7 is a sectional view for explaining the method for manufacturing the AlGaAs semiconductor laser having the BH structure according to the first embodiment of the present invention.

FIG. 8 is a sectional view showing an AlGaAs-based semiconductor laser having a BH structure according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view for explaining the method for manufacturing the AlGaAs semiconductor laser having the BH structure according to the second embodiment of the present invention.

FIG. 10 is a cross-sectional view for explaining the method for manufacturing the AlGaAs-based semiconductor laser having the BH structure according to the second embodiment of the present invention.

FIG. 11 is a cross-sectional view for explaining a method of manufacturing an AlGaAs-based semiconductor laser having a BH structure according to a second embodiment of the present invention.

FIG. 12 is a sectional view showing an AlGaAs-based semiconductor laser having an SDH structure according to a third embodiment of the present invention.

FIG. 13 is a cross-sectional view for explaining a method for manufacturing an AlGaAs-based semiconductor laser having an SDH structure according to a third embodiment of the present invention.

FIG. 14 is a sectional view for explaining a method for manufacturing an AlGaAs-based semiconductor laser having an SDH structure according to a third embodiment of the present invention.

FIG. 15 is a cross-sectional view for explaining the method for manufacturing the AlGaAs-based semiconductor laser having the SDH structure according to the third embodiment of the present invention.

FIG. 16 is a sectional view showing an AlGaAs-based semiconductor laser having an SDH structure according to a fourth embodiment of the present invention.

FIG. 17 is a cross-sectional view showing a conventional BH-structured AlGaAs-based semiconductor laser.

FIG. 18 is a cross-sectional view for explaining a method of manufacturing a conventional AlGaAs semiconductor laser having a BH structure.

FIG. 19 is a cross-sectional view for explaining a conventional method of manufacturing an AlGaAs-based semiconductor laser having a BH structure.

FIG. 20 is a cross-sectional view for explaining a conventional method for manufacturing an AlGaAs-based semiconductor laser having a BH structure.

FIG. 21 is a cross-sectional view for describing a method of manufacturing a conventional AlGaAs semiconductor laser having a BH structure.

FIG. 22: Undoped AlGaAs on a GaAs substrate
5 is a graph showing a profile of an impurity concentration in a depth direction in a sample on which an s layer and an AlGaAs layer doped with Se are grown.

FIG. 23 shows undoped AlGaAs on a GaAs substrate.
5 is a graph showing a profile of an impurity concentration in a depth direction in a sample on which an s layer and an AlGaAs layer doped with Zn are grown.

FIG. 24: Al doped with Se on a GaAs substrate
5 is a graph showing a profile of an impurity concentration in a depth direction in a sample in which a GaAs layer, an undoped AlGaAs layer, and a Zn-doped AlGaAs layer are grown.

FIG. 25 is a graph showing the results of measuring the Se concentration in a GaAs layer by SIMS when a GaAs layer doped with Se is grown on a GaAs substrate having a different crystal plane.

[Explanation of symbols]

1 ... n-type GaAs substrate, 2 ... n-type Al _x1 Ga
_1-x1 As clad layer, 3 ... Al _x2 Ga _1-x2 As active layer, 4 ... p-type Al _x1 Ga _1-x1 As clad layer, 5,
10 ... p-type GaAs cap layer, 6 ... # 11
1｝ B plane, 7 ... Se atomic layer, 8 ... p-type Al _x1 G
a _1-x1 As buried layer, 9... n-type Al _x1 Ga _1-x1 A
s buried layer, 14 ... Se atom

Claims (18)

[Claims] 1. A semiconductor having a stripe portion having a structure in which an active layer is sandwiched between a p-type cladding layer and an n-type cladding layer, and including a p-type semiconductor layer and an n-type semiconductor layer on both sides of the stripe portion. The semiconductor layer including the active layer, the p-type clad layer, the n-type clad layer, and the p-type semiconductor layer and the n-type semiconductor layer is a group III-V group having a zinc-blende type crystal structure. In the semiconductor light emitting device made of a compound semiconductor, the p-type cladding layer and / or the diffusion blocking layer for acceptor impurities of the p-type semiconductor layer is provided on at least a portion of the side surface of the stripe portion corresponding to the side surface of the active layer. And the diffusion blocking layer is made of a group III-V compound semiconductor having a zinc-blende-type crystal structure into which a donor impurity is introduced, or a donor impurity. Semiconductor light-emitting element. 2. The semiconductor according to claim 1, wherein the donor impurity used in the diffusion blocking layer is the same as the donor impurity used in the n-type semiconductor layer and / or the n-type cladding layer. Light emitting element. 3. The semiconductor light emitting device according to claim 1, wherein said acceptor impurity is Zn, and said donor impurity is Se. 4. The semiconductor light emitting device according to claim 1, wherein said diffusion blocking layer is further provided between said active layer and said p-type cladding layer. 5. The diffusion blocking layer between the active layer and the p-type cladding layer is made of a group III-V compound semiconductor having a zinc-blende-type crystal structure having a larger forbidden body width than the active layer. The semiconductor light emitting device according to claim 4, wherein: 6. A method according to claim 1, wherein the side surface of the stripe portion is # 11.
2. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device comprises a crystal plane which is off by a predetermined angle from the 1 @ B plane or the {111} B plane. 7. A semiconductor having a stripe portion having a structure in which an active layer is sandwiched between a p-type cladding layer and an n-type cladding layer, and including a p-type semiconductor layer and an n-type semiconductor layer on both sides of the stripe portion. A semiconductor layer including the active layer, the p-type cladding layer, the n-type cladding layer, and the p-type semiconductor layer and the n-type semiconductor layer, wherein the active layer, the p-type cladding layer, and the n-type semiconductor layer are group III-V having a zinc-blende-type crystal structure A p-type clad layer and / or a diffusion blocking layer for acceptor impurities of the p-type semiconductor layer, which is formed of a compound semiconductor, at least in a portion corresponding to a side surface of the active layer among side surfaces of the stripe portion; The method for manufacturing a semiconductor light emitting device comprising a group III-V compound semiconductor having a zinc-blende-type crystal structure into which a donor impurity is introduced or a donor impurity, The diffusion blocking layer is formed by adsorbing the donor impurity on the side surface of the rib portion, or the n-type semiconductor layer covers at least a portion of the side surface of the stripe portion corresponding to the side surface of the active layer. Wherein the diffusion blocking layer is formed by selectively introducing the donor impurity into the n-type semiconductor layer on the side surface of the stripe portion. Manufacturing method. 8. The semiconductor according to claim 7, wherein the donor impurity used in the diffusion blocking layer is the same as the donor impurity used in the n-type semiconductor layer and / or the n-type cladding layer. A method for manufacturing a light-emitting element. 9. The semiconductor light emitting device according to claim 7, wherein said acceptor impurity is Zn, and said donor impurity is Se. 10. The semiconductor light emitting device according to claim 7, wherein said stripe portion is formed by etching a structure in which said active layer is sandwiched between said p-type cladding layer and said n-type cladding layer. Device manufacturing method. 11. The stripe portion has a structure in which the n-type clad layer, the active layer, and the p-type clad layer are sequentially stacked, and the diffusion blocking layer has an etching for forming the stripe portion. After the above p
11. The method for manufacturing a semiconductor light emitting device according to claim 10, wherein the donor impurity is formed by adsorbing the donor impurity on a side surface of the stripe portion before forming the mold semiconductor layer. 12. The stripe portion has a structure in which the p-type clad layer, the active layer, and the n-type clad layer are sequentially laminated, and the diffusion blocking layer has an etching for forming the stripe portion. After the above p
Before forming the type semiconductor layer, the n-type semiconductor layer is formed so as to cover a portion corresponding to the side surface of the active layer among the side surfaces of the stripe portion. The method of manufacturing a semiconductor light emitting device according to claim 10, wherein the semiconductor light emitting device is formed by selectively introducing the donor impurity into the type semiconductor layer. 13. The semiconductor light emitting device according to claim 7, wherein said stripe portion is formed in a process of forming a structure in which said active layer is sandwiched between said p-type cladding layer and said n-type cladding layer. Device manufacturing method. 14. The stripe portion has a structure in which the n-type clad layer, the active layer, and the p-type clad layer are sequentially laminated, and the diffusion blocking layer forms the active layer after forming the active layer. 2. The method according to claim 1, wherein the step of forming the p-type cladding layer includes forming the side surface of the stripe portion by adsorbing the donor impurity.
3. The method for manufacturing a semiconductor light emitting device according to item 3. 15. The stripe portion has a structure in which the p-type clad layer, the active layer, and the n-type clad layer are sequentially laminated, and the diffusion blocking layer is formed during the formation of the n-type clad layer. 14. The method of manufacturing a semiconductor light emitting device according to claim 13, wherein the donor impurity is formed by adsorbing the donor impurity on a side surface of the stripe portion. 16. The method according to claim 7, further comprising forming the diffusion blocking layer between the active layer and the p-type cladding layer. 17. The diffusion blocking layer between the active layer and the p-type cladding layer is made of a group III-V compound semiconductor having a zinc-blende-type crystal structure having a larger forbidden body width than the active layer. 17. The method for manufacturing a semiconductor light emitting device according to claim 16, wherein: 18. The method according to claim 18, wherein the side surface of the stripe portion is # 11.
8. The method for manufacturing a semiconductor light emitting device according to claim 7, wherein the semiconductor light emitting device comprises a crystal plane that is off by a predetermined angle from the 1 @ B plane or the {111} B plane.