JPH11150333A - Semiconductor light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting element of a structure, wherein the overflow of carriers from an active layer to optical waveguide layers can be inhibited and the element is constituted using a high-quality II-VI compound semiconductor material which is excellent in life characteristics. SOLUTION: An n-type Zn1-x Mgx Sy Se1-y clad layer 5, an n-type Sn1-u Mgu Sy Se1-v optical waveguide layer 6, an active layer 7 consisting of a Zn1-z Cdz Se layer, a p-type Zn1-u Mgu Sv Se1-v optical waveguide layer 8 and a p-type Zn1-x Mgx Sv Se1-v clad layer 9 are laminated in order on an n-type GaAs substrate 1 via buffer layers to form a laser structure. The compositions of the layers 6 and 8 are chosen so that the absolute value of a lattice mismatching Δa/a to the substrate 1 is 0.01 or lower, a difference between the band gaps of the layer 7 and the layer 6 and the gaps of the layer 7 and the layer 8 is 0.3 eV or higher and a difference between the refractive indexes between the layers 5 and 6 and between the layers 8 and 9 is 0.1 or higher. As one example, the (x), the (y), the (u), the (v) and the (z) are used on the conditions of x=0.25, y=0.28, u=0.11, v=0.16 and z=0.25.

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 using a II-VI compound semiconductor, such as a semiconductor laser or a light emitting diode.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for semiconductor light emitting elements such as semiconductor lasers and light emitting diodes capable of emitting blue or green light in order to increase the recording / reproducing density and resolution of optical disks or magneto-optical disks. Research is being actively conducted to achieve this.

[0003] Materials used for manufacturing such a semiconductor light emitting device capable of emitting blue or green light include Zn and C.
Group II elements such as d, Mg, Hg, Be and S, Se, T
Group II-VI compound semiconductors comprising Group VI elements such as e and O are promising. In particular, quaternary mixed ZnMgS
Se has excellent crystallinity and can be easily grown on a GaAs substrate. For example, a cladding layer or an optical waveguide layer when a semiconductor laser capable of emitting blue light is manufactured using this GaAs substrate. (For example, Electronics Letters 28 (1992) p. 1798).

Conventionally, as such a semiconductor laser, ZnCdSe is an active layer, ZnSSe is an optical waveguide layer,
ZnCdSe / Zn with nMgSSe as cladding layer
SSe / ZnMgSSe SCH (Separate Confineme
nt Heterostructure) is known. Specifically, this ZnCdSe / ZnSSe / Zn
In a semiconductor laser having an MgSSe SCH structure, an n-type Z
An nMgSSe cladding layer, an n-type ZnSSe optical waveguide layer, for example, an active layer having a single quantum well (SQW) structure using an undoped ZnCdSe layer as a quantum well layer, a p-type ZnSSe optical waveguide layer, and a p-type ZnMgSSe cladding layer are sequentially laminated. Further, on this p-type ZnMgSSe cladding layer, as a p-type contact layer, a p-type ZnSSe cap layer, a p-type ZnSe contact layer, and a p-type ZnSe / ZnT
An e multiple quantum well (MQW) layer and a p-type ZnTe contact layer are sequentially stacked. Upper layer of p-type ZnSSe cap layer, p-type ZnSe contact layer, p-type ZnSe
The / ZnTe MQW layer and the p-type ZnTe contact layer have a stripe shape extending in one direction, and an insulating layer made of a polyimide film is provided on the p-type ZnSSe cap layer in a portion other than the stripe portion. Is formed. The p-side electrode is in contact with the p-type ZnTe contact layer and the insulating layer, and the n-side electrode is in contact with the back surface of the n-type GaAs substrate.

[0005]

However, in the semiconductor laser having the above-mentioned ZnCdSe / ZnSSe / ZnMgSSe SCH structure, the ZnC
Since the dSe layer is a strained layer, increasing the amount of strain increases the band gap difference between the optical waveguide layer and the active layer.
Characteristics deteriorate due to the influence of distortion. Therefore, the Cd composition of the ZnCdSe layer constituting the active layer is desirably about 25%, and the thickness is desirably equal to or less than the critical thickness, for example, about 4 nm. The emission wavelength at this time is about 500 nm. However, in this case, ZnCdSe / ZnSS
In the e / ZnMgSSe SCH structure, the difference in band gap between the optical waveguide layer and the active layer is as small as about 0.2 eV, and the overflow of carriers from the active layer to the optical waveguide layer increases. Problem. Therefore, from the viewpoint of suppressing carrier overflow, it is necessary to increase the band gap of the optical waveguide layer. However, at this time, if the band gap of the cladding layer is increased, the effective acceptor concentration N _A -N _{D of} the p-type ZnMgSSe cladding layer decreases. For this reason,
The band gap difference between the cladding layer and the active layer is 0.
The band gap can be increased only to a value of about 4 eV. As a material of the optical waveguide layer, ZnSSe having a band gap intermediate between the band gap of the cladding layer and the band gap of the active layer is used. Is currently used.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a semiconductor light emitting device using a high quality II-VI compound semiconductor, which can suppress the overflow of carriers from the active layer to the optical waveguide layer and has excellent life characteristics. To provide.

[0007]

In order to achieve the above object, the present invention provides a substrate, a first cladding layer of a first conductivity type on the substrate, and a first optical waveguide on the first cladding layer. A wave layer, an active layer on the first optical waveguide layer, a second optical waveguide layer on the active layer, and a second cladding layer of the second conductivity type on the second optical waveguide layer. , A first cladding layer, a first optical waveguide layer,
The active layer, the second optical waveguide layer, and the second cladding layer have a Z
at least one or more group II elements selected from the group consisting of n, Cd, Mg, Hg and Be, and S, Se, Te
And O in a semiconductor light emitting device composed of a II-VI compound semiconductor comprising at least one or more group VI elements selected from the group consisting of: a first optical waveguide layer and a second optical waveguide layer. Lattice mismatch Δ to substrate
The absolute value of a / a (where a is the lattice constant of the substrate and Δa is the amount of change in the lattice constant) is 0.01 or less, and the absolute value of the first optical waveguide layer, the second optical waveguide layer, and the active layer The band gap difference between them is 0.3 eV or more.

[0008] In the present invention, the active layer is typically a strained layer. In this case, it is also possible to adjust the lattice mismatch Δa / a of the first optical waveguide layer and the second optical waveguide layer with respect to the substrate for the purpose of compensating for the distortion of the active layer. Specifically, for example, when the lattice constant of the active layer is larger than the lattice constant of the substrate and the active layer is under compressive strain, the lattice constants of the first optical waveguide layer and the second optical waveguide layer The composition of these layers is controlled so as to be smaller than the lattice constant. Note that even when the active layer is a strained layer, the first optical waveguide layer and the second optical waveguide layer may be lattice-matched to the substrate.

In the present invention, typically, the first cladding layer and the second cladding layer are made of a ZnMgSSe-based compound semiconductor, and the first optical waveguide layer and the second optical waveguide layer are made of a ZnMgSSe-based semiconductor. , The active layer is Be
It is made of a ZnCdSe-based semiconductor or a ZnCdSe-based semiconductor.

In the present invention, the first optical waveguide layer and the second optical waveguide layer are provided between the first optical waveguide layer and the second optical waveguide layer and between the second optical waveguide layer and the second optical waveguide layer, respectively. 2
A third optical waveguide layer and a fourth optical waveguide layer having a band gap smaller than that of the first optical waveguide layer. In this case, the thicknesses of the first optical waveguide layer and the second optical waveguide layer are preferably, for example, 10 nm or less so as not to hinder carrier injection into the active layer. Also, in this case,
For example, the first cladding layer and the second cladding layer are Z
The first optical waveguide layer and the second optical waveguide layer are made of a ZnMgSSe-based semiconductor, and the third optical waveguide layer and the fourth optical waveguide layer are made of ZnMgSSe.
The active layer is made of a Se-based semiconductor or a ZnSSe-based semiconductor, and the active layer is made of a BeZnCdSe-based semiconductor.
The first clad layer and the second clad layer are BeMgZ
the first optical waveguide layer and the second optical waveguide layer are made of a BeZnSe-based semiconductor;
And the fourth optical waveguide layer are made of a BeZnSe-based semiconductor, and the active layer is made of a BeZnCdSe-based semiconductor.

According to the present invention, when the semiconductor light emitting device is a semiconductor laser, in particular, the distance between the first optical waveguide layer and the second optical waveguide layer and the first cladding layer and the second cladding layer is reduced. The refractive index difference is preferably selected to be, for example, 0.1 or more. When the semiconductor light emitting device is a light emitting diode, the difference in refractive index between the first optical waveguide layer and the second optical waveguide layer and the first clad layer and the second clad layer is 0 or more. I just need.

According to the present invention configured as described above, the difference in band gap between the first optical waveguide layer and the second optical waveguide layer and the active layer is 0.3 eV or more. The carrier is prevented from overflowing from the active layer to the first optical waveguide layer and the second optical waveguide layer.
At this time, the absolute value of the lattice mismatch Δa / a of the first optical waveguide layer and the second optical waveguide layer with respect to the substrate is 0.01
By the following, even when the active layer is a strained layer, the first optical waveguide layer and the second optical waveguide layer can be coherently (defects can be reduced) without lattice relaxation of the active layer. Can be stacked).

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In all the drawings of the embodiments, the same or corresponding portions are denoted by the same reference numerals.

FIG. 1 is a sectional view of a semiconductor laser according to a first embodiment of the present invention. This semiconductor laser has S
It has a CH structure.

As shown in FIG. 1, in this semiconductor laser, an n-type impurity doped with, for example, Si is used.
N-type GaAs buffer layer 2, n-type
-Type ZnSe buffer layer 3, n-type ZnSSe buffer layer 4, n-type _{Zn 1-x Mg x S y} Se 1-y cladding layer 5, n
Type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6, for example, SQ is a Zn _1-z Cd z Se layer of undoped quantum well layer
Active layer 7 of the W structure, p-type _{Zn 1-u Mg u S v} Se 1-v optical guide layer 8, p-type _{Zn 1-x Mg x S y} Se 1-y cladding layer 9, p-type ZnSSe cap layer 10 , P-type ZnSe contact layer 11, p-type ZnSe / ZnTe multiple quantum well (MQW) layer 12, and p-type ZnTe contact layer 13
Are sequentially laminated.

Here, the n-type GaAs buffer layer 2 has
For example, Si is doped as an n-type impurity and n-type ZnS
e-buffer layer 3, n-type ZnSSe buffer layer 4, n-type Z
n _1-x Mg _x S _y Se _1-y clad layer 5 and n-type Zn
_1-u Mg u S _v to the Se _1-v optical waveguide layer 6, as for example Cl is n-type impurity respectively doped, p-type Zn _1-u M
g _u S _v Se _1-v optical guide layer 8, p-type Zn _1-x Mg x S _y
Se _1-y clad layer 9, p-type ZnSSe cap layer 1
0, p-type ZnSe contact layer 11, p-type ZnSe / Z
The p-type ZnSe layer and the p-type ZnTe layer of the nTe layer 12 and the p-type ZnTe
For example, N is doped as a type impurity.

An upper layer portion of the p-type ZnSSe cap layer 10,
p-type ZnSe contact layer 11, p-type ZnSe / ZnT
eMQW layer 12 and p-type ZnTe contact layer 13
Have a stripe shape extending in one direction. P-type ZnSSe cap layer 10 in portions other than the stripe portion
An insulating layer 14 such as a polyimide film is provided thereon to form a current confinement structure. The insulating layer 14 is made of, for example, Al ₂ O ₃
May be used.

The insulating layer 14 and the stripe-shaped p
For example, Pd / Pt is formed on the type ZnTe contact layer 13.
A / Au structure p-side electrode 15 is provided in ohmic contact with the p-type ZnTe contact layer 113.
On the other hand, on the back surface of the n-type GaAs substrate 1, an n-side electrode 16 such as an In electrode is provided in ohmic contact.

In this semiconductor laser, the Cd composition ratio z of the Zn _{1 -z} Cd _z Se layer forming the active layer 7 is, for example, 0.1 or more and 0.3 or less, specifically, for example, 0.25. At this time, the band gap E ₁ is about 2.48 eV. Zn _1-z C having this Cd composition ratio z = 0.25
The d _z Se active layer 7 has a positive polarity with respect to the n-type GaAs substrate 1.
It has a lattice mismatch Δa / a of 0.017. This active layer 7 is a strained layer that has been subjected to compressive strain.

Further, n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v Mg composition ratio u of the optical waveguide layer 8 is for example 0 .11, the S composition ratio v is, for example, 0.16, and the band gap E _{2 at} that time is about 2.88 eV. These Mg composition ratios u = 0.1
N-type Zn _1-u M having 1 and S composition ratio v = 0.16
g _u S _v Se _1-v optical waveguide layer 5 and the p-type Zn _1-u Mg u
The S _v Se _1-v optical waveguide layer 8 is lattice-matched to the n-type GaAs substrate 1.

The Mg composition ratio x of the n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5 and the p-type Zn _1-x Mg _x S _y Se _1-y clad layer 9 is, for example, 0.25. , S composition ratio y
Is, for example, 0.28, and the band gap E at that time is
₃ is about 3.08 eV. These Mg composition ratios x =
N-type Zn having 0.25 and S composition ratio y = 0.28
_1-x Mg _x S _y Se _1-y clad layer 5 and p-type Zn
_{The 1-x} Mg _x S _y Se _{1 -y} cladding layer 9 is lattice-matched to the n-type GaAs substrate 1.

[0022] In this case, n-type _{Zn 1-u Mg u S v} Se
_1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v
The difference in band gap between the optical waveguide layer 8 and the active layer 7 is about 0.4 eV, and furthermore, n-type Zn _1-x Mg _x S _y S
e _1-y clad layer 5 and p-type Zn _1-x Mg _x S _y Se
The difference in band gap between the _1-y cladding layer 9 and the active layer 7 is about 0.6 eV. Further, n-type Zn _1-u Mg _u S
_v Se _1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} S
Refractive index between the e _1-v optical waveguide layer 8 and the n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5 and the p-type Zn _1-x Mg _x S _y Se _1-y clad layer 9 The difference Δn is 0.1 or more.

[0023] n-type _{Zn 1-x Mg x S y} Se 1-y cladding layer 5, n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6, Z
Active layer 7 made of n _{1 -z} Cd _z Se layer, p-type Zn _{1 -uM}
g _u S _v Se _1-v optical waveguide layer 8 and the p-type Zn _1-x Mg x
S _y Se _1-y clad layer 9 (x = 0.25, y = 0.2
8, u = 0.11, v = 0.16, z = 0.25) is shown in FIG. In FIG. 2,
E _C is the energy at the bottom of the conduction band, and E _V is the energy at the top of the valence band.

[0024] The thickness of the n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 is preferably for example 10nm chosen 500nm inclusive, specifically, n-type _{Zn 1-u Mg u S v} Se 1-v
The thickness of the optical guide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 is chosen in each example 300 nm. In this case, p-type Zn _1-x Mg _x S _y Se _1-y
The clad layer 9 has a band gap E ₃ of about 3.08 eV.
It is difficult to perform high-concentration impurity doping, and it is difficult to increase the p-type carrier concentration. Therefore, the p-type Zn _1-x Mg _x S _y Se _1-y clad layer 9
The thickness of the, p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8
The thickness is adjusted in consideration of the series resistance of the semiconductor laser as well as the thickness. In this case, specifically, the p-type Zn
The thickness of the _1-x Mg _x S _y Se _1-y cladding layer 9 is, for example, 2
00 nm.

The n-type GaAs buffer layer 2 has a thickness of, for example, 0.5 μm, the n-type ZnSe buffer layer 3 has a thickness of, for example, 10 nm, the n-type ZnSSe buffer layer 4 has a thickness of, for example, 50 nm, and an n-type ZnMgSSe cladding. The thickness of the layer 5 is, for example, 1 μm, and the thickness of the active layer 7 is, for example, 3 to 4 n.
The thickness of the m, p type ZnSSe cap layer 10 is, for example, 50
0 nm, the thickness of the p-type ZnSe contact layer 11 is, for example, 100 nm, and the thickness of the p-type ZnTe contact layer 13 is, for example, 100 nm.

Next, a method of manufacturing the semiconductor laser according to the first embodiment having the above-described structure will be described.

To manufacture this semiconductor laser, first,
MBE for growing III-V compound semiconductor not shown
The n-type GaAs substrate 1 is mounted on a substrate holder in a vacuum vessel evacuated to an ultra-high vacuum of the apparatus. Next, the n-type Ga
After heating the As substrate 1 to a predetermined growth temperature, the n-type G
An n-type GaAs buffer layer 2 is grown on an aAs substrate 1 by MBE. In this case, doping of Si, which is an n-type impurity, is performed using a Si molecular beam source (Knudsen cell). The growth of the n-type GaAs buffer layer 2 is performed by heating the n-type GaAs substrate 1 to a temperature of, for example, about 580 ° C. and thermally etching the surface to remove a surface oxide film and clean the surface. May be done after

Next, the n-type GaAs substrate 1 on which the n-type GaAs buffer layer 2 has been grown as described above is transferred to the above-described MBE apparatus for growing a III-V compound semiconductor through a vacuum transfer path (not shown). From the substrate to the MBE apparatus for growing a II-VI compound semiconductor shown in FIG. Then, in the MBE apparatus shown in FIG. 3, each II-VI group compound semiconductor layer forming the laser structure is grown. In this case, the surface of the n-type GaAs buffer layer 2 is kept clean since it is not exposed to the air during its transfer to the MBE apparatus shown in FIG. 3 after its growth.

As shown in FIG. 3, in this MBE apparatus, a substrate holder 22 is provided in a vacuum vessel 21 evacuated to an ultra-high vacuum by an ultra-high vacuum exhaust device (not shown). Is held. A plurality of molecular beam sources (Knudsen cells) 23 are mounted in the vacuum vessel 21 so as to face the substrate holder 22. In this case, as the molecular beam source 23, Z
n, Se, Mg, ZnS, Te, Cd and ZnCl ₂
Molecular beam sources such as are provided. These molecular beam sources 2
A shutter (not shown) is provided in front of each of the shutters 3 so as to be opened and closed. A plasma cell 24 using electron cyclotron resonance (ECR) or radio frequency (RF) is further mounted inside the vacuum vessel 21 so as to face the substrate holder 22.

Now, in order to grow each II-VI compound semiconductor layer forming a laser structure on the n-type GaAs buffer layer 2, the MBE apparatus shown in FIG.
The n-type GaAs substrate 1 on which the n-type GaAs buffer layer 2 has been grown is mounted on the substrate holder 22 in 1. Next, the n-type GaAs substrate 1 is set at a predetermined growth temperature, for example, about 250 ° C., and growth by the MBE method is started.
That is, on the n-type GaAs buffer layer 2, n-type ZnS
e-buffer layer 3, n-type ZnSSe buffer layer 4, n-type Z
n _1-x Mg _x S _y Se _1-y clad layer 5, n-type Zn _1-u
Mg _u S _v Se _1-v optical waveguide layer 6, active layer 7, p-type Zn
_{1-u Mg u S v Se} 1-v optical guide layer 8, p-type Zn _1-x Mg
_x S _y Se _1-y cladding layer 9, p-type ZnSSe layer 10,
p-type ZnSe contact layer 11, p-type ZnSe / ZnT
An eMQW layer 12 and a p-type ZnTe contact layer 13 are sequentially grown.

N-type ZnSe buffer layer 3, n-type ZnSS
e-buffer layer 4, n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5, n-type Zn _1-u Mg _{u Sv} Se _1-v optical waveguide layer 6
Doping of Cl as an n-type impurity is, for example, Zn
This is performed using Cl ₂ as a dopant. In addition, p-type Zn
_{1-u Mg u S v Se} 1-v optical guide layer 8, p-type Zn _1-x Mg
_x S _y Se _1-y cladding layer 9, p-type ZnSSe cap layer 10, p-type ZnSe contact layer 11, p-type ZnSe
The doping of N as a p-type impurity in the / ZnTe MQW layer 12 and the p-type ZnTe contact layer 13 is performed by using N ₂ gas introduced from a gas introduction pipe (not shown) in the plasma cell 24 of the MBE apparatus shown in FIG. Plasma is formed, and N ₂ plasma generated thereby is irradiated on the substrate surface.

Next, after forming a stripe-shaped resist pattern (not shown) extending in one direction on the p-type ZnTe contact layer 13 by lithography, the resist pattern is used as a mask to form p-type resist by, for example, wet etching. Etching is performed to an intermediate depth in the thickness direction of the type ZnSSe cap layer 10. Thus, the upper layer portion of the p-type ZnSSe cap layer 10, the p-type ZnSe contact layer 11, the p-type ZnSe / ZnTe MQW layer 12, and the p-type ZnTe contact layer 13 are patterned in a stripe shape.

Next, a polyimide film is formed on the entire surface by a CVD method or the like while leaving the resist pattern used for the etching as it is. Thereafter, the resist pattern is removed together with the polyimide film thereon (lift-off). As a result, the upper portion of the p-type ZnSSe cap layer 10 patterned in a stripe shape, p
-Type ZnSe contact layer 11, p-type ZnSe / ZnTe
An insulating layer 14 is formed on both sides of the MQW layer 12 and the p-type ZnTe contact layer 13.

Next, a Pd film, a Pt film, and an Au film are sequentially formed on the entire surface of the stripe-shaped p-type ZnTe contact layer 13 and the insulating layer 14 on both sides thereof by, for example, a vacuum deposition method to form Pd / Pt / Au. A p-side electrode 15 having a structure is formed. Thereafter, a heat treatment is performed as needed to bring the p-side electrode 15 into ohmic contact with the p-type ZnTe contact layer 13. On the other hand, an n-side electrode 16 such as an In electrode is formed on the back surface of the n-type GaAs substrate 1.

Next, the n-type GaAs substrate 1 on which the laser structure has been formed as described above is cleaved into a bar shape to form both resonator end faces, and, if necessary, end face coating. The bar is cleaved into chips. The laser chip thus obtained is mounted on a heat sink, packaged, and a target semiconductor laser is manufactured.

[0036] As described above, according to the first embodiment, n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1- _v optical waveguide layer 8 and the active layer 7
Difference in band gap than 0.3eV between (in this case, the difference in band gap between them of about 0.4 eV) by a, these n-type _{Zn 1-u Mg u S v} Se 1-v
The optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8, it is possible to prevent the carrier from the active layer 7 overflows, an excellent semiconductor laser life characteristics Can be realized. Moreover, n-type Zn
_{1-u Mg u S v Se} 1-v optical waveguide layer 6 and the p-type Zn _1-u
Mg _u S _v and Se _1-v optical waveguide layer 8, n-type Zn _1-x Mg x
S _y Se _1-y clad layer 5 and p-type Zn _1-x Mg _x S
_When the refractive index difference between the _y Se _1-y clad layer 9 is 0.1 or more, light confinement is also good. Also,
n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8, n-type GaA
Due to the lattice matching with the s-substrate 1, the Zn _1-z Cd _z Se layer constituting the active layer 7 does not undergo lattice relaxation. Therefore, this semiconductor laser has high quality and good characteristics.

Next, a second embodiment of the present invention will be described. In the semiconductor laser according to the second embodiment, the C _{1 -Z} Cd _z Se layer
When the d composition ratio z is 0.25 (the band gap E ₄
Is 2.48 eV) and has the same Cd composition ratio z as in the first embodiment, but n-type Zn _1-x Mg _x S
_y Se _1-y clad layer 5 and p-type Zn _1-x Mg _x S _y
Se _1-y cladding layer 9 of Mg composition ratio x, S composition ratio y, and, n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se Mg of _1-v optical waveguide layer 8
The composition ratio u and the S composition ratio v are different from those in the first embodiment.

That is, in this semiconductor laser,
n-type Zn _1-u Mg u S _v bandgap Se _1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 has been changed in the thickness direction, Therefore, this semiconductor laser has a GRIN (Graded Index) -SCH structure. In this case, n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8
Changes in the Mg composition ratio u of these layers
Is given by adjusting. In this case, n
Type _{Zn 1-u Mg u S v} Se 1-v Mg composition ratio u of the optical waveguide layer 6 is chosen in the following section, for example, 0 to 0.10 which is in contact with the active layer 7, n-type Zn from the active layer 7 side _1-x Mg _x S _y S
The S _{1 -y} cladding layer 5 is made to gradually increase in the thickness direction toward the cladding layer 5 side, and the S composition ratio v is, for example, 0.06 or more and 0.
It is selected to be about 18 or less and is made constant in the thickness direction.
Similarly, p-type _{Zn 1-u Mg u S v} Mg composition ratio u of Se _1-v optical waveguide layer 8, a portion in contact with the active layer 7, for example 0 to 0.10 chosen below the active layer 7 side From p-type Zn _1-x M
The g _x S _y Se _{1 -y} cladding layer 9 is made to gradually increase in the thickness direction toward the cladding layer 9 side, and the S composition ratio v is, for example, 0.0.
The thickness is selected from about 6 to about 0.18 and is constant in the thickness direction.

[0039] Specifically, n-type _{Zn 1-u Mg u S v} Se
_1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v
Of the optical waveguide layer 8, Mg composition ratio of a portion in contact with the active layer 7 u is, for example 0.07, S composition ratio v is 0.18 for example, the band gap E ₅ at that time is about 2.82eV . N-type Zn _1-u Mg _u S _v Se _1-v having these Mg composition ratio u = 0.07 and S composition ratio v = 0.18
Optical guide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 is approximately -0.7% with respect to n-type GaAs substrate 1
Lattice mismatch Δa / a. Also, n-type Zn _1-u M
g _u S _v Se _1-v optical waveguide layer 6 and the p-type Zn _1-u Mg u
N-type Zn _1-x Mg _x S of the S _v Se _1-v optical waveguide layer 8
_y Se _1-y clad layer 5 and p-type Zn _1-x Mg _x S _y
The Mg composition ratio u of the portion in contact with the Se _1-y clad layer 9 is, for example, 0.12, the S composition ratio v is, for example, 0.18, and the band gap E _{6 at} that time is about 2.90 eV.
These Mg composition ratio u = 0.12 and S composition ratio v =
N-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 having a 0.18 includes an n-type GaAs substrate 1 Lattice matching.

Here, these n-type Zn _1-u Mg _u S _v
Se _1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se
_{The 1-v} optical waveguide layer 8 has a lattice constant smaller than the lattice constant of the n-type GaAs substrate 1 as a whole, and suppresses the distortion of the active layer 7 having a lattice constant larger than the lattice constant of the n-type GaAs substrate 1. Compensate. In this case, the n-type Zn _1-u Mg _u
S _v Se _1-v optical waveguide layer 6 and the p-type Zn _1-u Mg u S _v
Se _1-v absolute value of the lattice mismatch .DELTA.a / a for n-type GaAs substrate 1 of the optical waveguide layer 8, since that is the 0.7% at most, n-type _{Zn 1-u Mg u S v} Se 1 _-v optical guide layer 6, active layer 7 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 is coherently (so that it does not contain defects)
Since they are stacked, the active layer 7 does not undergo lattice relaxation.

The Mg composition ratio x of the n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5 and the p-type Zn _1-x Mg _x S _y Se _1-y clad layer 9 is, for example, 0.12. As described above, specifically, for example, 0.12, and the S composition ratio y is, for example, 0.18
Above, specifically a 0.18 example, the band gap E ₇ at this time is about 2.90eV. These M
An n-type Zn _1-x Mg _x S _y Se _1-y cladding layer 5 having a g composition ratio x = 0.12 and an S composition ratio y = 0.18, and a p-type Zn _1-x Mg _x S _y Se _{1- The y} cladding layer 9 is lattice-matched to the n-type GaAs substrate 1. In this case, the n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5 and the n-type Z
_{n 1-u Mg u S v} Se 1-v optical waveguide layer 6, the composition in both of the interface are consistent, similarly, p-type Zn _1-x Mg
_x S _y Se _1-y cladding layer 9 and the p-type Zn _1-u Mg u
The composition of the S _v Se _1-v optical waveguide layer 8 is also the same at the interface between them.

[0042] In this case, the active layer 7 and the n-type in a portion in contact _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 And the active layer 7 have a band gap difference of about 0.34 eV, and n
Type Zn _1-x Mg _x S _y Se _1-y clad layer 5 and p-type Zn _1-x Mg _x S _y Se _1-y clad layer 9 and Zn _1-z C
The difference in band gap between the active layer 7 and the d _z Se layer 7 is about 0.5.
4 eV. Moreover, definitive part in contact with the active layer 7 n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type Zn
_{1-u Mg u S v Se} 1-v optical waveguide layer 8 and the n-type Zn _1-x Mg
_x S _y Se _1-y cladding layer 5 and the p-type Zn _1-x Mg x
The refractive index difference Δn between the S _y Se _1-y clad layer 9 is
0.1 or more.

N-type Zn _1-x Mg _x S _y Se _1-y cladding layer 5, n-type Zn _1-u Mg _{u Sv} Se _1-v optical waveguide layer 6, Z
Active layer 7 made of n _{1 -z} Cd _z Se layer, p-type Zn _{1 -uM}
g _u S _v Se _1-v optical waveguide layer 8 and the p-type Zn _1-x Mg x
S _y Se _1-y clad layer 9 (x = 0.12, y = 0.1
8, 0.07 ≦ u ≦ 0.12, v = 0.18, z = 0.
FIG. 4 shows an energy band diagram of 25). FIG.
, E _C is the energy at the bottom of the conduction band,
_V is the energy at the top of the valence band.

[0044] The thickness of the n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 are each for example 100nm , N-type Zn
_1-x Mg _x S _y Se _1-y clad layer 5 and p-type Zn
The thickness of the _1-x Mg _x S _y Se _1-y cladding layer 9 is, for example, 1 μm.

The other structure of this semiconductor laser is
The description is omitted because it is the same as that of the semiconductor laser according to the embodiment.

The method of manufacturing the semiconductor laser is the same as the method of manufacturing the semiconductor laser according to the first embodiment, and a description thereof will not be repeated.

[0047] As described above, according to this second embodiment, in addition to it is possible to obtain the same advantages as the first embodiment, n-type _{Zn 1-u Mg u S v} Se 1-v waveguide by controlling the composition of the layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8, a lattice mismatch .DELTA.a / a for n-type GaAs substrate 1 of the layers, the thickness direction By changing the stress, the strain applied to the active layer 7 can be reduced by compensating for the distortion of the active layer 7.
As a result, a semiconductor laser having higher quality and excellent operation characteristics can be realized.

Next, a third embodiment of the present invention will be described. FIG. 5 is a sectional view of the semiconductor laser according to the third embodiment. This semiconductor laser has an SCH structure.

As shown in FIG. 5, in the semiconductor laser according to the third embodiment, n-type Zn _1-x Mg _x S _y
Se _1-y cladding layer 5 and the n-type _{Zn 1-u Mg u S v} Se
N-type Zn _1-p Mg _p S _q Se between the _1-v optical waveguide layer 6
_{The 1-q} optical waveguide layer 31 is inserted, and the p-type Zn _1-u Mg _u S _v
Se _1-v optical waveguide layer 8 and p-type Zn _1-x Mg _x S _y Se _1-y
Between the cladding layer and the p-type Zn _1-p Mg _p S _q Se _1-q
The optical waveguide layer 32 is inserted. These n-type Zn _1-p
Mg _p S _q Se _1-q optical waveguide layer 31 and the p-type Zn _1-p M
g _p S _q Se _1-q optical waveguide layer 32, n-type Zn _1-u Mg u
S _v Se _1-v optical waveguide layer 6 and the p-type Zn _1-u Mg u S _v
It has a band gap smaller than the Se _1-v optical waveguide layer 8.

In the semiconductor laser, the Cd composition ratio z of the Zn _{1 -z} Cd _z Se layer forming the active layer 7 is, for example, 0.1 or more and 0.3 or less, specifically, for example, 0.25. At this time, the band gap E ₈ is about 2.48 eV. Zn _1-z C having this Cd composition ratio z = 0.25
The d _z Se active layer 7 has a positive polarity with respect to the n-type GaAs substrate 1.
It has a lattice mismatch Δa / a of 0.017. This active layer 7 is a strained layer that has been subjected to compressive strain.

The n-type Z provided adjacent to the active layer 7
_{n 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type Zn
_{1-u Mg u S v Se} 1-v As distortion compensation of the active layer 7 is performed by the optical waveguide layer 8, these n-type Zn _1-u Mg
_{u Sv} Se _1-v optical waveguide layer 6 and p-type Zn _1-u Mg _u S
_v Se _1-v optical waveguide layer 8 has lattice mismatch Δa / a (however,
The absolute value is 0.01 or less).
This lattice mismatch Δa / a is, for example, due to the n-type Zn
_{1-u Mg u S v Se} 1-v optical waveguide layer 6 and the p-type Zn _1-u
Mg _u S _v Se _1-v combination of Mg composition ratio u and S composition ratio v as the optical waveguide layer 8 are lattice matched with the n-type GaAs substrate 1 (where, n-type Zn _1-u Mg _u S _v Se ₁ difference in band gap between the _-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 and the active layer 7 is 0.3e
V or more), the S composition ratio v
Is given by increasing Specifically, these n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v Mg composition ratio u of the optical waveguide layer 8 For example, the S composition ratio v is 0.18 or more and 0.30 or less, specifically, for example, 0.22, and the band gap E _{9 at} that time is about 2.92 eV. These Mg composition ratio u = 0.12 and S composition ratio v = 0.
N-type Zn with _{22 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8
Has a lattice mismatch Δa / a of −0.005 with respect to the n-type GaAs substrate 1.

[0052] In this case, these n-type Zn _1-u Mg u S _v
Se _1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se
_{The 1-v} optical waveguide layer 8 has a lattice constant smaller than the lattice constant of the n-type GaAs substrate 1 and compensates for the distortion of the active layer 7 having a lattice constant larger than the lattice constant of the n-type GaAs substrate 1. In this case, n-type _{Zn 1-u Mg u S v} Se
_1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v
Lattice mismatch Δ of optical waveguide layer 8 with n-type GaAs substrate 1
Since the absolute value of a / a is 1% or less, n-type Zn
_{1-u Mg u S v Se} 1-v optical waveguide layer 6, active layer 7 and p
Type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8 (so that it does not contain defects) coherently are laminated, the active layer 7 is not lattice relaxation.

The n-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 31 and the p-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 3
2 Mg composition ratio p is for example 0.05, S composition ratio q is 0.10 for example, the band gap E ₁₀ at that time is about 2.78 eV. Their Mg composition ratio p = 0.05
-Type Zn _1-p Mg having a composition ratio of S and q = 0.10
_{p Sq} Se _1-q optical waveguide layer 31 and p-type Zn _1-p Mg _p
The S _q Se _1-q optical waveguide layer 32 is lattice-matched with the n-type GaAs substrate 1.

The Mg composition ratio x of the n-type Zn _1-x Mg _x S _y Se _1-y cladding layer 5 and the p-type Zn _1-x Mg _x S _y Se _1-y cladding layer 9 is, for example, 0.12, S the composition ratio y is 0.18 for example, the band gap E ₁₁ at that time is about 2.90eV. The Mg composition ratio x = 0.12
And n-type Zn _1-x Mg having an S composition ratio y = 0.18
_x S _y Se _1-y cladding layer 5 and the p-type Zn _1-x Mg x
The S _y Se _1-y cladding layer 9 is lattice-matched to the n-type GaAs substrate 1.

[0055] In this case, n-type _{Zn 1-u Mg u S v} Se
_1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v
The difference in band gap between the optical waveguide layer 8 and the active layer 7 is 0.44 eV, and n-type Zn _1-p Mg _p S _q Se _1-q
Difference in band gap between the optical waveguide layer 31 and the p-type _{Zn 1-p Mg p S q} Se 1-q optical waveguide layer 32 and the active layer 7 is 0.3 eV, n-type Zn _1-x Mg x difference in band gap between the S _y Se _1-y cladding layer 5 and the p-type _{Zn 1-x Mg x S y} Se 1-y cladding layer 9 and the active layer 7 is about 0.42 eV.

The n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5, the n-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 31,
n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6, Zn _1-z
Active layer 7 made of cd _z Se layer, p-type Zn _1-u Mg u S
_v Se _1-v optical waveguide layer 8, p-type Zn _1-p Mg _p S _q Se
_1-q optical waveguide layer 32 and p-type Zn _1-x Mg _x S _y Se
_1-y cladding layer 9 (x = 0.12, y = 0.18, p =
0.05, q = 0.10, u = 0.12, v = 0.2
FIG. 6 shows an energy band diagram of (2, z = 0.25). In FIG. 6, E _C is the energy at the lower end of the conduction band, and E _V is the energy at the upper end of the valence band.

[0057] The thickness of the n-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6 and the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8, to the active layer 7 For example, the thickness is selected to be 10 nm or less, preferably 2 to 3 nm so as not to hinder carrier injection. Also, the n-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 3
1 and p-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 32
Is selected, for example, to about 100 nm so that sufficient light can be confined. Also, n-type Zn
_1-x Mg _x S _y Se _1-y clad layer 5 and p-type Zn
The thickness of the _1-x Mg _x S _y Se _1-y cladding layer 9 is, for example, 1 μm.

The other structure of this semiconductor laser is the first
The description is omitted because it is the same as that of the semiconductor laser according to the embodiment.

Since the method for manufacturing the semiconductor laser is the same as the method for manufacturing the semiconductor laser according to the first embodiment, the description is omitted.

Here, a light emitting diode (LED) having the same structure as the semiconductor laser according to the third embodiment
And operating the LED at an operating temperature of 80 ° C. and an operating current of 10
The change with time of the light output when operated under the condition of 0 mA was measured. This measurement result is shown in FIG. 7 as data of sample a. In FIG. 7, the horizontal axis indicates elapsed time (time),
One vertical axis indicates the output (mV) of the photodetector used for the measurement corresponding to the optical output of the measurement sample, and the other vertical axis indicates the operating voltage (V). FIG. 7 shows, for comparison, ZnCdSe / ZnSSe / ZnMgSSe as data of sample b.
The light output measurement results when the SCH structure is operated under the same conditions in the LED mode are also shown.

As shown in FIG. 7, the time required for the light output of this LED having the same structure as that of the semiconductor laser according to the third embodiment to become １ ／ of that at the start of the measurement is 4.9 hours. With respect to ZnCdSe / ZnSSe / ZnMg
The time required for the light output when the SSe SCH structure is operated in the LED mode to become の of that at the start of the measurement is 0.
Since it is 2 hours or less, the life characteristics of this LED are as follows:
It can be seen that they are better than those having the ZnCdSe / ZnSSe / ZnMgSSe SCH structure. From this, it is expected that the life characteristics of the semiconductor laser according to the third embodiment are also good.

FIG. 8 is a graph showing changes over time in operating current and operating voltage when the semiconductor laser according to the third embodiment is operated at a constant light output. Here, the semiconductor laser was operated under the conditions of an operating temperature of 80 ° C. and an optical output of 1 mW. The resonator length of the semiconductor laser used for this measurement was 600 μm, and a high reflection coating of 60% / 96% was applied to the resonator end face. In FIG.
The horizontal axis shows the elapsed time (time) in logarithm, one vertical axis shows the operating current (mA), and the other vertical axis shows the operating voltage (V).
In FIG. 8, a curve a is a graph of the operating current, and a curve b is a graph of the operating voltage. As shown in FIG. 8, this semiconductor laser was operated at an operating temperature of 80 ° C. and an optical output of 1 mW.
, The operating current at the start of the measurement is about 40 mA and the operating voltage is about 4 V. The element life at which the operating current and the operating voltage rapidly increase is about 1.
It turns out that it is 5 hours. The operating current, operating voltage and element life are compared with those of a semiconductor laser having a ZnCdSe / ZnSSe / ZnMgSSe SCH structure manufactured under the same growth conditions as usual (the life is about 0.1 hour at an operating temperature of 80 ° C.). Good.

[0063] As described above, according to this third embodiment, in addition to it is possible to obtain the same advantages as the first embodiment, n-type _{Zn 1-u Mg u S v} Se 1-v waveguide the layers 6 and p-type _{Zn 1-u Mg u S v} Se 1-v S composition ratio v of the optical waveguide layer 8, and larger than the S composition ratio v of when the n-type GaAs substrate 1 and the lattice matching, the active By compensating for the strain in the layer 7, the stress applied to the active layer 7 can be reduced, thereby realizing a semiconductor laser with higher quality and excellent operating characteristics. At this time, the distortion of the active layer 7 is compensated for by using an n-type Zn _1-u M having a thickness of 10 nm or less provided near the active layer 7.
g _u S _v Se _1-v optical waveguide layer 6 and the p-type Zn _1-u Mg u
This can be performed only with the S _v Se _1-v optical waveguide layer 8.

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 idea of the present invention are possible.

For example, the structures and materials of the semiconductor lasers according to the above-described first to third embodiments are merely examples.
If necessary, a different structure or material may be used.
Specifically, the Mg listed in the first to third embodiments
The numerical values of the composition ratios x, u, p, S composition ratios y, v, q, and Cd composition ratio z are merely examples, and Mg composition ratios x, u, p, S composition ratios y, which are different from these, if necessary. v, q and Cd
The composition ratio z may be used.

Further, for example, an active layer having an MQW structure may be used instead of the active layer 7 having an SQW structure in the first to third embodiments. Further, for example, the optical waveguide layers in the first to third embodiments may be undoped. Further, for example, the p-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 31 and the p-type Z
Instead of the n _1-p Mg _p S _q Se _1-q optical waveguide layer 32, respectively, an n-type ZnSSe optical waveguide layer and a p-type ZnSSe
An optical waveguide layer may be used. In addition, for example, the above first to first
In the third embodiment, the structure may be such that the n-type ZnSSe buffer layer 4 is omitted.

For example, in the third embodiment, the n-type Zn _1-x Mg _x S _y Se _1-y clad layer 5 is used.
An n-type BeMgZnSe cladding layer and a p-type BeMgZnSe cladding layer are used instead of the p-type Zn _1-x Mg _x S _y Se _1-y cladding layer 9, respectively.
N-type adjacent to the _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 6
And in place of the p-type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer 8, respectively, n-type BeZnSe optical waveguide layer and a p-type BeZnSe optical waveguide layer, a Zn _1-z Cd z Se layer instead of the active layer 7 made, with the active layer made of BeZnCdSe layer, n-type _{Zn 1-x Mg x S y} Se 1-y cladding layer 5 and the n-type _{Zn 1-u Mg u S v} Se 1-v light N-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 31 and p-type Zn _1-u Mg _{u Sv} Se _1-v optical waveguide layer 8 between p-type Zn _1- Instead of the p-type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer 32 between the _x Mg _x S _y Se _1-y cladding layer 9, the n-type BeZnSe optical waveguide layer and the p-type BeZn
Se optical waveguide layer (however, n-type BeZn adjacent to the active layer)
A material having a smaller band gap than the Se optical waveguide layer and the p-type BeZnSe optical waveguide layer) may be used.

In the first to third embodiments described above, the MBE method is used for growing the II-VI compound semiconductor layer. A metal chemical vapor deposition (MOCVD) method may be used.

Further, in the first to third embodiments, the case where the present invention is applied to a semiconductor laser has been described. However, the present invention can be applied to a light emitting diode. Further, the present invention can be applied to a semiconductor light emitting device using a p-type semiconductor substrate.

[0070]

As described above, according to the present invention, the difference in band gap between the first optical waveguide layer and the second optical waveguide layer and the active layer is 0.3 eV or more. 1
Since the absolute value of the lattice mismatch Δa / a of the optical waveguide layer and the second optical waveguide layer with respect to the substrate is 0.01 or less, the active layer can be moved from the first optical waveguide layer to the second optical waveguide layer. Carrier overflow can be suppressed, and a high-quality semiconductor light emitting device having excellent life characteristics can be realized.

[Brief description of the drawings]

FIG. 1 shows a II-VI according to a first embodiment of the present invention.
1 is a cross-sectional view of a semiconductor laser using a group III compound semiconductor.

FIG. 2 shows II-VI according to the first embodiment of the present invention.
FIG. 3 is an energy band diagram of a semiconductor laser using a group III compound semiconductor.

FIG. 3 shows II-VI according to the first embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating an example of a configuration of an MBE apparatus used for manufacturing a semiconductor laser using a group III compound semiconductor.

FIG. 4 shows II-VI according to a second embodiment of the present invention.
FIG. 3 is an energy band diagram of a semiconductor laser using a group III compound semiconductor.

FIG. 5 shows a II-VI according to a third embodiment of the present invention.
1 is a cross-sectional view of a semiconductor laser using a group III compound semiconductor.

FIG. 6 shows a II-VI according to a third embodiment of the present invention.
FIG. 3 is an energy band diagram of a semiconductor laser using a group III compound semiconductor.

FIG. 7 shows II-VI according to a third embodiment of the present invention.
4 is a graph showing a temporal change of an optical output and an operating voltage when an LED having a structure similar to that of a group III compound semiconductor is operated at a high temperature with a constant operating current.

FIG. 8 shows a II-VI according to a third embodiment of the present invention.
4 is a graph showing a change over time of an operating current and an operating voltage when a semiconductor laser using a group III compound semiconductor is operated at a constant optical output.

[Explanation of symbols]

1 ... n-type GaAs substrate, 5 ... n-type Zn _1-x Mg
_x S _y Se _1-y cladding layer, 6 · · · n-type Zn _1-u Mg
_{u Sv} Se _1-v optical waveguide layer, 7 ... active layer, 8 ... p
Type _{Zn 1-u Mg u S v} Se 1-v optical waveguide layer, 9 · · · p-type _{Zn 1-x Mg x S y} Se 1-y cladding layer, 31 · · · n
Type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer, 32 ... p
Type Zn _1-p Mg _p S _q Se _1-q optical waveguide layer

Claims (11)

[Claims] 1. A substrate, a first cladding layer of a first conductivity type on the substrate, a first optical waveguide layer on the first cladding layer, and an active layer on the first optical waveguide layer. A second optical waveguide layer on the active layer, a second cladding layer of a second conductivity type on the second optical waveguide layer, the first cladding layer, the first cladding layer, The optical waveguide layer, the active layer, the second optical waveguide layer, and the second cladding layer each include at least one group II element selected from the group consisting of Zn, Cd, Mg, Hg, and Be. S, S
a semiconductor light emitting device comprising a II-VI group compound semiconductor comprising at least one or more group VI elements selected from the group consisting of e, Te and O, wherein the first optical waveguide layer and the second The absolute value of the lattice mismatch Δa / a (where a is the lattice constant of the substrate and Δa is the amount of change in the lattice constant) of the optical waveguide layer is 0.01
A semiconductor light emitting device, wherein: a band gap difference between the first optical waveguide layer and the second optical waveguide layer and the active layer is 0.3 eV or more. 2. The semiconductor light emitting device according to claim 1, wherein said active layer is a strained layer. 3. The semiconductor light emitting device according to claim 1, wherein said active layer is a strained layer, and said first optical waveguide layer and said second optical waveguide layer are lattice-matched with said substrate. . 4. The active layer is a strained layer, and the first optical waveguide layer and the second optical waveguide layer have the lattice mismatch Δa / a that compensates for the strain of the active layer. 2. The semiconductor light emitting device according to claim 1, wherein: 5. The semiconductor light emitting device according to claim 4, wherein the lattice mismatch Δa / a of the first optical waveguide layer and the second optical waveguide layer changes in a thickness direction. . 6. The method according to claim 1, wherein a difference in refractive index between the first optical waveguide layer and the second optical waveguide layer and the first clad layer and the second clad layer is 0.1 or more. The semiconductor light emitting device according to claim 1, wherein: 7. The first cladding layer and the second cladding layer are made of a ZnMgSSe-based compound semiconductor,
The first optical waveguide layer and the second optical waveguide layer are made of ZnM
gSSe-based semiconductor, and the active layer is BeZnCd
2. The semiconductor light emitting device according to claim 1, comprising a Se-based semiconductor or a ZnCdSe-based semiconductor. 8. The first optical waveguide is provided between the first cladding layer and the first optical waveguide layer and between the second optical waveguide layer and the second cladding layer, respectively. 2. The semiconductor light emitting device according to claim 1, further comprising a third optical waveguide layer and a fourth optical waveguide layer having a layer and a band gap smaller than that of the second optical waveguide layer. 9. The active layer is a strained layer, and the first optical waveguide layer and the second optical waveguide layer have a lattice mismatch Δa / a that compensates for distortion of the active layer. 9. The semiconductor light emitting device according to claim 8, wherein said third optical waveguide layer and said fourth optical waveguide layer are lattice-matched with said substrate. 10. The first cladding layer and the second cladding layer.
Is made of a ZnMgSSe-based compound semiconductor, and the first optical waveguide layer and the second optical waveguide layer
The third optical waveguide layer and the fourth optical waveguide layer are made of a ZnMgSSe-based semiconductor or a ZnSSe-based semiconductor, and the active layer is made of BeZn.
9. The semiconductor light emitting device according to claim 8, comprising a CdSe-based semiconductor or a ZnCdSe-based semiconductor. 11. The first cladding layer and the second cladding layer.
Is made of a BeMgZnSe-based compound semiconductor, and the first optical waveguide layer and the second optical waveguide layer
9. The semiconductor light emitting device according to claim 8, wherein the third optical waveguide layer and the fourth optical waveguide layer are made of eZnSe-based semiconductor, and the active layer is made of BeZnCdSe-based semiconductor. .