JPH06140670A - Semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To reduce operation voltage by forming a low-resistance electrode in a II-V wide gap semiconductor layer, concerning a semiconductor light emitting device emitting blue or green light. CONSTITUTION:In the laminate structure, which includes an active layer 6 consisting of a II-IV wide gap semiconductor, guide layers 5 and 7, clad layers 4 and 8, etc., group II-VI semiconductor layers and III-V semiconductor layers roughly an integer times as thick as a single molecular layer are formed alternately so that the ratio of the thickness of this III-V semiconductor layer may increase gradually as it separates from the II-VI wide gap semiconductor, whereby a hetero barrier lightening layer 9a having a band gap decreasing gradually in curve shape or step shape is formed, and an electrode 12 is made on the surface. Or, an electrode formation layer 10 consisting of III-V semiconductor layer is made on this hetero lightening layer 9a, and an electrode 12 is made on the surface. Or, this hetero barrier lightening layer is made of chalcopyrite mixed crystal layer or HgZnSSe mixed crystal layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device which emits blue to green light.

[0002]

2. Description of the Related Art With the recent sophistication of crystal growth technology, it has become possible to realize a current injection type semiconductor laser which emits blue or green light and which is composed of a II-VI group semiconductor, which has been conventionally regarded as difficult. It's coming.

The major impetus for this situation was I
Two technologies: the realization of a high-quality heterojunction structure using a group I-VI semiconductor, and the favorable p-type doping by using nitrogen by a radical beam as an impurity. Development.

FIG. 7 is a diagram showing the structure of a conventional semiconductor light emitting device. In this figure, 21 is an n-GaAs substrate,
22 is an n-GaAs buffer layer, 23 is an n-ZnSe buffer layer, 24 is an n-ZnSSe clad layer, and 25 is n.
-ZnSe guide layer, 26 CdZnSe quantum well active layer, 27 p-ZnSe guide layer, 28 p-ZnSS
e is a clad layer, 29 is a p-ZnSe electrode forming layer, 30 is a polyimide film, 31 is an Au electrode, and 32 is an In electrode.

In this conventional semiconductor light emitting device, n
On the -GaAs substrate 21, the n-GaAs buffer layer 2
2, n-ZnSe buffer layer 23, n-ZnSSe cladding layer 24, n-ZnSe guide layer 25, CdZnSe
Quantum well active layer 26, p-ZnSe guide layer 27, p-
ZnSSe clad layer 28, p-ZnSe electrode formation layer 2
9 are sequentially formed by the MBE method, and a polyimide film 30 having openings is formed thereon.
An Au electrode 31 reaching the p-ZnSe electrode forming layer 29 through the opening 0 is formed, and an In electrode 32 is formed on the bottom surface of the n-GaAs substrate 21. And above, p
-ZnSe guide layer 27, p-ZnSSe cladding layer 2
8. Nitrogen is used as the p-type impurity of the p-ZnSe electrode forming layer 29.

[0006]

In the conventional semiconductor light emitting device shown in FIG. 7, a good p-type semiconductor layer can be formed by nitrogen doping, and ZnSe can be formed.
The II-VI group semiconductor layer and the GaAs layer can be grown in a lattice-matched state, and the n-type electrode can be formed on the bottom surface of the GaAs substrate in a satisfactory state.

However, many problems still remain in order to put this conventional semiconductor light emitting device into practical use. That is, in this conventional semiconductor light emitting device, ZnSe
Has not been sufficiently reduced, and p-Z
A satisfactory low contact resistance material has not been found for the nSe electrode forming layer 29.

Therefore, since the voltage drop at the electrode portion becomes large, the operating voltage of the semiconductor light emitting device becomes high, and the current injection type laser oscillation currently realized is a pulsed oscillation at room temperature, and a continuous oscillation. Was limited to the temperature condition of 77K which is the liquid nitrogen temperature. In the technical field of application of semiconductor light emitting devices in the blue or green visible light region, which is an urgent issue at present, it is essential to realize continuous oscillation at room temperature or higher temperature.

According to the present invention, in a blue to green semiconductor light emitting device composed of such a II-VI wide-gap semiconductor, a low resistance electrode is formed on the II-VI wide-gap semiconductor and an operating voltage is increased. The purpose is to reduce.

[0010]

In the semiconductor light emitting device of the first type according to the present invention, II-V such as ZnSe is used.
An active layer made of a group I wide gap semiconductor, a guide layer,
A II-VI group semiconductor layer such as ZnSe having a thickness that is an integral multiple of a monolayer and a G-layer in a laminated structure including a clad layer and the like.
The group III-V semiconductor layers such as aAs are alternately formed so that the thickness ratio of the group III-V semiconductor layers gradually increases as the distance from the group II-VI wide gap semiconductor layers increases. A structure in which a semiconductor layer having a gradually decreasing band gap is formed and an electrode is formed on the surface of the semiconductor layer is adopted.

In addition, in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI group wide-gap semiconductor, the II-VI has a thickness which is an integral multiple of that of a monomolecular layer.
The group semiconductor layers and the group III-V semiconductor layers are alternately formed such that the thickness ratio of the group III-V semiconductor layers gradually increases as the distance from the group II-VI wide gap semiconductor layers increases. A semiconductor layer having a gradually decreasing band gap is formed, and an electrode forming layer made of a III-V group semiconductor such as GaAs is formed on the surface of the semiconductor layer.

Further, in the semiconductor light emitting device of the second type according to the present invention, Cu (AlGa) is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI group wide gap semiconductor such as ZnSe. ) (SeTe) ₂
A structure was adopted in which a chalcopyrite mixed crystal layer such as a mixed crystal was formed, and an electrode was formed on the surface of the chalcopyrite crystal layer.

Further, a chalcopyrite mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI group wide gap semiconductor, and a chalcopyrite crystal layer is formed on a surface of the chalcopyrite III layer such as GaAs. A structure in which an electrode forming layer made of a -V semiconductor is formed is adopted.

In this case, it is possible to adopt a structure in which the chalcopyrite mixed crystal layer is composed of a plurality of layers, and each layer has a band gap that gradually decreases with distance from the II-VI group wide gap semiconductor layer.

Further, in this case, the chalcopyrite mixed crystal layer is composed of a compositionally graded layer which continuously changes, and II-VI
It is possible to adopt a configuration having a bandgap that gradually decreases as the distance from the group wide-gap semiconductor layer increases.

In the semiconductor light emitting device of the third type according to the present invention, a HgZnSSe mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide gap semiconductor such as ZnSe. Is formed,
An electrode was formed on the surface of the HgZnSSe mixed crystal layer.

Further, a HgZnSSe mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI group wide gap semiconductor, and the HgZnSS is formed.
A structure in which an electrode forming layer made of a III-V group semiconductor such as GaAs is formed on the surface of the e mixed crystal layer is adopted.

In this case, it is possible to adopt a structure in which the HgZnSSe mixed crystal layer is composed of a plurality of layers, and each layer has a bandgap that gradually decreases with distance from the II-VI group wide gap semiconductor layer.

Further, in this case, the HgZnSSe mixed crystal layer may be composed of a compositionally graded layer that continuously changes, and may have a bandgap that gradually decreases with distance from the II-VI wide gap semiconductor layer.

[0020]

As described above, when an electrode is directly formed on a II-VI group wide-gap semiconductor such as ZnSe that emits blue to green light, the band gap of this semiconductor is large, so that the semiconductor layer and the electrode are separated. It has been difficult to obtain a good low resistance electrode due to high contact resistance or Schottky junction between them. Since the contact resistance tends to be smaller as the band gap is smaller, the band gap is gradually reduced by some method to obtain 1.6 ev.
If it is possible to form the electrode after having reached a certain degree, the low resistance electrode can be formed.

In the semiconductor light emitting device of the first type of the present invention (corresponding to claims 1 to 3 in the claims), an active layer and a guide made of a II-VI group wide gap semiconductor such as ZnSe. ZnS having a thickness which is almost an integral multiple of a monolayer in a laminated structure including layers, clad layers, etc.
II-VI semiconductor layer such as e and III-V such as GaAs
The group semiconductor layers are alternately formed such that the thickness ratio of the group III-V semiconductor layers gradually increases as the distance from the group II-VI wide gap semiconductor layers increases, and the effective band gap is gradually reduced. A good p-type electrode is obtained by forming an electrode on the surface.

Further, in the semiconductor light emitting device of the second type of the present invention (corresponding to claims 4 to 9 in the claims), a laminated structure made of a II-VI group wide gap semiconductor such as ZnSe. In addition, Cu (AlGa) (S
A good p-type electrode is obtained by forming a chalcopyrite mixed crystal layer such as eTe) ₂ to gradually reduce the band gap and forming an electrode on the surface of this chalcopyrite mixed crystal layer.

In the semiconductor light emitting device of the third type of the present invention (corresponding to claims 10 to 14 of the claims), a laminated structure made of a II-VI group wide gap semiconductor such as ZnSe. A HgZnSSe mixed crystal layer is formed on the HgZnSSe to gradually reduce the band gap.
An excellent p-type electrode is obtained by forming an electrode on the surface of the gZnSSe mixed crystal layer.

In the semiconductor light emitting device of the first type of the present invention, the semiconductor layer is formed by alternately forming the II-VI group semiconductor layers and the III-V group semiconductor layers, and the second aspect of the present invention.
In the chalcopyrite mixed crystal layer in the semiconductor light emitting device of the type II, and in the HgZnSSe mixed crystal layer in the semiconductor light emitting device of the third type of the present invention.
An electrode forming layer made of a group IV semiconductor is formed, and an electrode is further formed on this electrode forming layer.

When an electrode formation layer of a III-V group semiconductor such as GaAs is formed on the uppermost layer of a II-VI group semiconductor layer such as ZnSe, p-type and n-type G that have been accumulated in the past are formed.
An electrode forming technique for III-V group semiconductors such as aAs can be applied.

However, when a group III-V semiconductor such as GaAs is directly formed on a group II-VI semiconductor layer such as ZnSe, for example, the band gaps of ZnSe and GaAs are about 2.70 eV and 1.42 eV, respectively. 1.3e
Since there is a difference in V, the resistance to holes is significantly increased.

Therefore, as described above, by inserting the semiconductor layer whose energy gap gradually decreases between the II-VI group semiconductor layer and the III-V group semiconductor layer, the II-V group is formed.
Since the band gap between the group I semiconductor layer and the group III-V semiconductor layer can be continuously connected to reduce the resistance to holes, the band gap difference in the group II-VI semiconductor layer such as ZnSe can be reduced. A good electrode can be easily formed without causing an increase in resistance to holes due to it.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings of the present invention.

(First Embodiment) FIG. 1 is a structural explanatory view of a semiconductor light emitting device of the first embodiment. In this figure, 1 is an n-GaAs substrate, 2 is an n-GaAs buffer layer, 3 is an n-ZnSe buffer layer, 4 is an n-ZnSSe cladding layer, 5 is an n-ZnSe guide layer, and 6 is a CdZnSe strained quantum well activity. Layer, 7 is p-ZnSe guide layer, 8 is p-
ZnSSe clad layer, 9a is a heterobarrier relaxation layer, 1
0 is a p-GaAs electrode forming layer, 11 is a SiO ₂ insulating film,
Reference numeral 12 is an Au / Zn p-side electrode, and 13 is an Au / Gen side electrode.

In the semiconductor light emitting device of this embodiment,
On the n-GaAs substrate 1, the n-GaAs buffer layer 2, the n-ZnSe buffer layer 3, the n-ZnSSe cladding layer 4, the n-ZnSe guide layer 5, the CdZnSe strained quantum well active layer 6, and the p-ZnSe guide layer. 7, p-ZnS
Se clad layer 8, heterobarrier relaxation layer 9 described later
a, a p-GaAs electrode forming layer 10 is formed, a SiO ₂ insulating film 11 having an opening is formed thereon, and Au / Zn p is formed in the p-GaAs electrode forming layer 10 through the opening.
The side electrode 12 is formed, and A is formed on the bottom surface of the n-GaAs substrate 1.
The u / Gen side electrode 13 is formed.

The semiconductor light emitting device having this structure is widely used at present, and is a mature technique.
It can be easily manufactured by using a crystal growth method such as a PE method and an ALE method. And the above p-ZnS
Nitrogen is used as a p-type impurity in the e-guide layer 7 and the p-ZnSSe cladding layer 8, and the p-GaAs electrode forming layer 10 is formed.
Zinc is used as the p-type impurity.

This semiconductor light emitting device is the same as the conventional semiconductor light emitting device of FIG. 7 in terms of the structure of the active layer, the guide layer, and the cladding layer, but the p-type GaAs electrode forming layer is the uppermost layer on the p side. 10 is provided, and between the p-ZnSSe clad layer 8 and the p-GaAs electrode forming layer 10, the p-ZnSSe clad layer 8 to the p-ZnSSe clad layer 8 are provided.
A feature is that a heterobarrier relaxation layer 9a made of a ZnSe / GaAs short period superlattice in which the ratio of the GaAs layer gradually increases toward the GaAs electrode forming layer 10 is inserted.

FIG. 2 is an explanatory view of a ZnSe / GaAs short period superlattice, and FIG. 2A schematically shows its structure.
(B) shows an effective band gap. In this figure, 8, 9a and 10 are p-ZnS as in FIG.
Se clad layer 8, hetero barrier relaxation layer 9a, p-Ga
Represents the As electrode forming layer 10, 10: 1, 9: 1, 8:
1,7: 1, ..., 1: 8, 1: 9, 1:10 are Z
The ratio of the layer thicknesses of the nSe layer and the GaAs layer is shown.

The ZnSe layer and the GaAs layer typically have a layer thickness that is an integral multiple of the monomolecular layer, but in reality, if the integral multiple of the monomolecular layer is sufficient, there is no problem, and particularly exact adjustment is possible. Does not need Such a short-period superlattice is composed of GaAs
Since the lattice mismatch between ZnSe and ZnSe is 0.3%, and three-dimensional growth hardly occurs, the growth temperature is set to 300 to 400 ° C. using the MBE method, and the method of alternately supplying the raw materials is used. Can be easily formed by.

The short period superlattice shown in FIG. 2A is
(10ZnSe / 1GaAs) ₂ (9ZnSe / 1Ga)
As) ₂ (8ZnSe / 1GaAs) ₂ (7ZnSe /
1GaAs) ₂ (6ZnSe / 1GaAs) ₂ (5Zn
Se / 1GaAs) ₂ (4ZnSe / 1GaAs)
₂ (3ZnSe / 1GaAs) ₂ (2ZnSe / 1Ga
As) ₂ (1ZnSe / 1GaAs) ₂ ... (1Zn
Se / 9GaAs) ₂ (1ZnSe / 10GaAs) ₂
Has become. The number in front of each semiconductor indicates the ratio of the layer thickness, and the subscript 2 indicates that there are two periods.

FIG. 2B shows the effective bandgap of the heterobarrier relaxation layer. The bandgap of each portion is a value corresponding to the ratio of the layer thickness from the result of independent evaluation of each structural unit. Was confirmed. Thus, the p-ZnSSe cladding layer 8 and the p-G
The band gap between the aAs electrode formation layers 10 is continuously changed by the hetero barrier relaxation layer, and discontinuous barriers such as spikes that hinder the movement of holes do not occur.

In this embodiment, the heterobarrier relaxation layer is inserted only on the p side, but it can be inserted also on the n side to further reduce the resistance. Further, in this embodiment, the cladding layer and the guide layer are made of ZnSe, ZnSSe.
However, other materials, such as ZnMgSSe and ZnCdS, that emit light on the short wavelength side and have a good light and carrier confinement effect due to their large bandgap.
The present invention can be applied to the case of using another type such as Se. Also in this case, as the hetero barrier relaxation layer,
By using the ZnSe / GaAs combination structure as described above, the barrier can be sufficiently relaxed. Further, since the band gap on the surface of the hetero barrier relaxation layer 9a in this example is sufficiently reduced to 1.42 eV, an electrode is directly formed on the hetero barrier relaxation layer 9a itself without using the p-GaAs electrode forming layer 10. It can also be formed.

The operating voltage of the conventional semiconductor light emitting device shown in FIG. 7 was about 30 V, whereas the operating voltage of the semiconductor light emitting device of this embodiment was drastically reduced to 5 V, and the operating voltage of the electrode portion was reduced. Since the heat generation of the device is suppressed by the decrease of the resistance component, it was possible to realize the oscillation in the blue or green region at room temperature or higher.

(Second Embodiment) FIG. 3 is an explanatory view of the structure of a semiconductor light emitting device of the second embodiment. The reference numerals used in this figure are the same as those described with reference to the same reference numerals in FIG. 1, except that 9b is a heterobarrier relaxation layer made of chalcopyrite crystal.

In the semiconductor light emitting device of this embodiment, the heterobarrier relaxation layer 9b has chalcopyrite (I-III-VI).
₂ system) is the same as the first embodiment except that it is a mixed crystal, but n
On the -GaAs substrate 1, the n-GaAs buffer layer 2,
n-ZnSe buffer layer 3, n-ZnSSe cladding layer 4, n-ZnSe guide layer 5, CdZnSe strained quantum well active layer 6, p-ZnSe guide layer 7, p-ZnSSe.
Cladding layer 8, hetero barrier relaxation layer 9b, p-GaAs
The electrode forming layer 10 is formed and Si having an opening thereon is formed.
An O ₂ insulating film 11 is formed, and p-Ga is formed through this opening.
An Au / Zn p-side electrode 12 is formed on the As electrode forming layer 10, and an Au / Gen side electrode 13 is formed on the bottom surface of the n-GaAs substrate 1.

The semiconductor light emitting device of this embodiment is different from the semiconductor light emitting device of the first embodiment in that a p-ZnSSe cladding layer 8 and a p-GaAs electrode forming layer 10 are provided between the p-ZnSSe cladding layer 8 and the p-ZnSSe forming layer 10 as p- From the ZnSSe cladding layer 8 toward the p-GaAs electrode forming layer 10, CuAl
Cu (A) which is a chalcopyrite mixed crystal whose composition gradually changes from (SeTe) ₂ to CuGa (SeTe) ₂ .
This is the point where a compositionally graded layer of lGa) (SeTe) ₂ mixed crystal is inserted.

FIG. 4 shows Cu (AlGa) (SeTe) ₂
FIG. 3 is a relational diagram of a band gap of a mixed crystal and a lattice constant. As can be seen from this figure, Cu (AlGa) (SeTe) ₂
By changing the composition of the mixed crystal, the band gap can be changed along the broken line between 2.6 eV close to ZnSe and 1.6 eV close to GaAs with almost no change in the lattice constant.

Further, this Cu (AlGa) (SeTe)
It is also possible to replace the composition gradient layer of ₂ mixed crystal with a multilayer Cu (AlGa) (SeTe) ₂ mixed crystal whose composition changes discontinuously.

The heterobarrier relaxing layer is inserted only on the p side in the semiconductor light emitting device of FIG. 3, but by inserting it also on the n side, the resistance of the semiconductor light emitting device can be further reduced.

The cladding layer and the guide layer are made of the above-mentioned Zn.
In place of Se and ZnSSe, other materials such as ZnM
The present invention can be applied to the case of forming with gSSe, ZnCdSSe, or the like. Also in this case, as a material for forming the hetero barrier relaxation layer, Cu (AlG) is used as described above.
a) (SeTe) ₂ mixed crystal can be used.

In the semiconductor light emitting device of this embodiment,
Similar to the first embodiment described above, the operating voltage of the conventional semiconductor light emitting device having a configuration similar to this is about 30V.
However, the voltage is drastically reduced to 5 V, the heat generation of the device is suppressed due to the reduction of the resistance component in the electrode portion, and the oscillation in the blue or green region can be realized at room temperature or higher.

Further, the contact resistance tends to become smaller as the band gap becomes smaller, so that Cu (AlGa) (SeTe) multilayered on the p-ZnSSe cladding layer 8 is formed.
The Cu (AlGa) (SeTe) ₂ mixed crystal layer itself having a ₂ mixed crystal layer or a composition gradient layer thereof to gradually reduce the band gap and the band gap is reduced to 1.6 ev is used as an electrode forming layer. A low resistance electrode can be formed.

(Third Embodiment) FIG. 5 is a structural explanatory view of a semiconductor light emitting device of a third embodiment. The reference numerals used in this figure are the same as those described with reference to the same reference numerals in FIG. 1, except that 9c is a heterobarrier relaxing layer made of a HgZnSSe crystal layer.

The semiconductor light emitting device of this embodiment is the same as that of the second embodiment except that the heterobarrier relaxation layer 9b is chalcopyrite crystal, but on the n-GaAs substrate 1,
n-GaAs buffer layer 2, n-ZnSe buffer layer 3, n-ZnSSe cladding layer 4, n-ZnSe guide layer 5, CdZnSe strained quantum well active layer 6, p-ZnS
An e-guide layer 7, a p-ZnSSe clad layer 8, a heterobarrier relaxation layer 9c, and a p-GaAs electrode forming layer 10 are formed, and an SiO ₂ insulating film 11 having an opening is formed thereon, and a p-GaAs electrode is formed through this opening. A in the forming layer 10
The u / Zn p-side electrode 12 is formed, and the Au / Gen side electrode 13 is formed on the bottom surface of the n-GaAs substrate 1.

The semiconductor light emitting device of this embodiment differs from the semiconductor light emitting devices of the first and second embodiments in that p-
ZnSSe clad layer 8 and p-GaAs electrode forming layer 10
Between the hetero barrier relaxation layers 9c, p-ZnSS
The point is that a HgZnSSe heterobarrier relaxation layer whose composition gradually changes from HgZnS to ZnSe is inserted from the e-clad layer 8 to the p-GaAs electrode formation layer 10.

FIG. 6 is a diagram showing the relationship between the band gap and the lattice constant of the HgZnSSe mixed crystal. As can be seen from this figure, by changing the composition of the HgZnSSe mixed crystal,
The bandgap is 2.7 eV, which is close to that of ZnSe, and 1.
It can be changed along the broken line between 8 eV.

The compositionally graded layer of this HgZnSSe mixed crystal is a multi-layered HgZnSSe whose composition changes discontinuously.
It can be replaced with a mixed crystal. The heterobarrier relaxing layer is inserted only on the p side in the semiconductor light emitting device of FIG. 5, but by inserting it also on the n side, the resistance of the semiconductor light emitting device can be further reduced.

The cladding layer and the guide layer are made of the above-mentioned Zn.
In place of Se and ZnSSe, other materials such as ZnM
The present invention can be applied to the case of forming with gSSe, ZnCdSSe, or the like. Also in this case, as a material for forming the hetero barrier relaxation layer, HgZnSS is used as described above.
e mixed crystals can be used.

Also in this embodiment, as in the above-described embodiment, the operating voltage of the conventional semiconductor light emitting device having the same structure as this is about 30V, whereas it is drastically reduced to 5V, and the electrode portion is reduced. The heat generation of the device is suppressed due to the decrease of the resistance component at 1, and the oscillation in the blue or green region can be realized at room temperature or higher.

Since the contact resistance tends to become smaller as the band gap becomes smaller, a multilayered HgZnSSe mixed crystal layer or a composition gradient layer thereof is formed on the p-ZnSSe cladding layer 8 to gradually reduce the band gap. HgZnS after being reduced to 1.8 ev
A low resistance electrode can be formed even when the Se mixed crystal layer itself is used as an electrode forming layer.

[0056]

As described above, according to the present invention,
A low-resistance electrode can be formed on the II-VI wide-gap semiconductor layer, and thus the operating voltage of the semiconductor light emitting device can be reduced, thereby providing a semiconductor light emitting device that emits favorable blue or green light. can do.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a semiconductor light emitting device of a first embodiment.

2A and 2B are explanatory diagrams of a ZnSe / GaAs short-period superlattice, in which FIG. 2A schematically shows the structure and FIG. 2B shows an effective band gap.

FIG. 3 is a structural explanatory view of a semiconductor light emitting device of a second embodiment.

FIG. 4 is a relationship diagram between a band gap and a lattice constant of a Cu (AlGa) (SeTe) ₂ mixed crystal.

FIG. 5 is a structural explanatory view of a semiconductor light emitting device of a third embodiment.

FIG. 6 is a diagram showing the relationship between the band gap and the lattice constant of HgZnSSe mixed crystal.

FIG. 7 is a structural explanatory view of a conventional semiconductor light emitting device.

[Explanation of symbols]

1 n-GaAs substrate 2 n-GaAs buffer layer 3 n-ZnSe buffer layer 4 n-ZnSSe clad layer 5 n-ZnSe guide layer 6 CdZnSe strained quantum well active layer 7 p-ZnSe guide layer 8 p-ZnSSe clad layer 9a, 9b, 9c Heterobarrier relaxation layer 10 p-GaAs electrode formation layer 11 SiO ₂ insulating film 12 Au / Zn p-side electrode 13 Au / Gen side electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Horino 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (14)

[Claims] 1. A laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide-gap semiconductor, and a II-VI semiconductor layer and a III- group having a thickness which is an integral multiple of a monolayer. The group V semiconductor layers are alternately formed so that the ratio of the thickness of the group III-V semiconductor layers gradually increases as the distance from the group II-VI wide gap semiconductor layers increases, and a band gap that is gradually reduced is effectively formed. A semiconductor light-emitting device, comprising a semiconductor layer having the semiconductor layer, and an electrode formed on the surface of the semiconductor layer. 2. A laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide-gap semiconductor, and a II-VI semiconductor layer and a III- group having a thickness which is an integral multiple of a monomolecular layer. The group V semiconductor layers are alternately formed so that the ratio of the thickness of the group III-V semiconductor layers gradually increases as the distance from the group II-VI wide gap semiconductor layers increases, and a band gap that is gradually reduced is effectively formed. A semiconductor light-emitting device, comprising a semiconductor layer having the same, and an electrode forming layer made of a III-V group semiconductor such as GaAs formed on the surface of the semiconductor layer. 3. II-VI alternately formed in a laminated structure
3. The semiconductor light emitting device according to claim 1, wherein the group semiconductor layer is ZnSe and the group III-V semiconductor layer is GaAs. 4. A chalcopyrite mixed crystal layer is formed on the surface of a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide gap semiconductor, and an electrode is formed on the surface of the chalcopyrite mixed crystal layer. A semiconductor light-emitting device characterized by being formed. 5. A chalcopyrite mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI group wide gap semiconductor, and a III-V group is formed on the surface of the chalcopyrite mixed crystal layer. A semiconductor light emitting device having an electrode forming layer made of a semiconductor formed thereon. 6. The chalcopyrite mixed crystal layer is composed of a plurality of layers, each layer having a band gap that gradually decreases with distance from the II-VI wide gap semiconductor layer. 5. The semiconductor light emitting device described in 5. 7. The chalcopyrite mixed crystal layer is composed of a compositionally graded layer that continuously changes, and has a band gap that gradually decreases with distance from the II-VI group wide gap semiconductor layer. The semiconductor light emitting device according to claim 5. 8. The method according to claim 5, wherein the group III-V semiconductor forming the electrode forming layer formed in the chalcopyrite mixed crystal layer is GaAs. Semiconductor light emitting device. 9. The chalcopyrite mixed crystal layer is made of Cu (AlG
a) (SeTe) ₂ mixed crystal, The semiconductor light emitting device according to any one of claims 4 to 8. 10. A HgZnSSe mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide gap semiconductor, and the HgZnSSe mixed crystal layer is formed.
A semiconductor light emitting device having an electrode formed on the surface of a mixed crystal layer. 11. A HgZnSSe mixed crystal layer is formed in a laminated structure including an active layer, a guide layer, a clad layer and the like made of a II-VI wide-gap semiconductor, and the HgZnSSe mixed crystal layer is formed.
A semiconductor light-emitting device, wherein an electrode forming layer made of a III-V group semiconductor is formed on the mixed crystal layer. 12. The HgZnSSe mixed crystal layer is composed of a plurality of layers, each layer having a band gap that gradually decreases with distance from the II-VI group wide gap semiconductor layer. The semiconductor light emitting device described in. 13. The HgZnSSe mixed crystal layer is composed of a compositionally graded layer that continuously changes, and has a band gap that gradually decreases with distance from the II-VI group wide gap semiconductor layer. Item 11. The semiconductor light emitting device according to item 11. 14. The group III-V semiconductor forming the electrode forming layer formed on the surface of the HgZnSSe mixed crystal layer is GaA.
The semiconductor light emitting device according to claim 11, wherein the semiconductor light emitting device is s.