JPH10290046A - Algainp semiconductor light-emitting element and optical disc recording device and/or regenerative device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of an AlGaInP semiconductor light-emitting element while meeting such requirements as miniaturization, an increase in light output, high-temperature operation and low noise. SOLUTION: In an AlGaInP semiconductor light-emitting element, at least one layer of a crystal defect propagation inhibition layer 11 consisting of a compound semiconductor, which contains at least an InP, is inserted in the clad layer on at least one side of an n-type clad layer and a p-type clad layer. As the layer 11, a single layer 4 of an InP layer, which has a superlattice formed by laminating alternately InP and GaP layers having a thickness thinner than a critical film thickness and has a thickness thinner than the critical film thickness, is used. This AlGaInP semiconductor light-emitting element is used as a light-emitting element of an optical disc recording device and/or a regenerative device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an AlGaInP
The present invention relates to a system semiconductor light emitting device and an optical disk recording and / or reproducing device.

[0002]

2. Description of the Related Art As AlGaInP-based semiconductor light emitting devices, semiconductor lasers and light emitting diodes having an emission wavelength of about 680 nm have been mass-produced and put to practical use in various applications.
In recent years, in this AlGaInP-based semiconductor light emitting device, the emission wavelength has been reduced to 650 nm or 635 nm, and at the same time, the size of the device body has been reduced, and
There has been a demand for an increase in optical output to a W class, operation at a high temperature of 60 to 80 ° C., low noise, and the like.

[0003]

However, at present, AlGaInP-based semiconductor light-emitting devices satisfy the above-mentioned requirements and are compatible with existing far-infrared-wavelength GaAs-based semiconductor light-emitting devices and long-wavelength InP-based semiconductor light-emitting devices. It is difficult to maintain equivalent life characteristics. This is Al
This is because in a GaInP-based semiconductor light emitting device, the higher the operating temperature, the light output density, the injection current density, and the like, and the specific stress, the more the deterioration is caused in a short time.

Accordingly, an object of the present invention is to reduce the size,
An AlGaInP-based semiconductor light-emitting device that can achieve a long life while satisfying the requirements of high light output, high-temperature operation, low noise, and the like, and a long-life optical disk recording using the AlGaInP-based semiconductor light-emitting device as a light-emitting device. And / or to provide a playback device.

[0005]

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

[0006] In general, the state of deterioration observed in a semiconductor light emitting device is roughly classified into a deterioration region, a bulk deterioration inside a semiconductor crystal constituting the semiconductor light emitting device, an end face deterioration, and an electrode deterioration. Of these, bulk degradation is caused by the formation, proliferation,
This is due to movement, and is a cause of many deteriorations from rapid deterioration to slow deterioration.

For example, a dark line defect (DLD), which is seen as a dark line in a light emission pattern when an AlGaAs-based semiconductor laser is energized, is a typical deterioration mode that causes rapid deterioration. This DLD is mainly <1
It often extends in the <00> direction and the <110> direction. The DLD grows in the dislocation network due to the dislocation ascending motion. The DLD grows while emitting and absorbing point defects, and the DLD grows by slip dislocation. In any case, the occurrence of DLD increases non-radiative recombination and absorption loss in the resonator, and eventually destroys the device. This is faster as the injection current density is higher and the operating temperature is higher.

On the other hand, in an InP-based semiconductor laser, rapid degradation due to the DLD is hardly observed. This is thought to be because the generation, propagation, and migration of crystal defects are unlikely to occur in InP-based materials, but details are unknown at this time.

The details of the AlGaInP-based semiconductor laser are not known at this time. However, since degradation due to DLD is observed, the direction in which the dislocation proceeds and the mechanism thereof may differ. And a degradation mode similar to AlGaAs semiconductor lasers.

On the other hand, although the slow deterioration of the semiconductor laser is currently being studied, the point defect in the cladding layer having a high doping concentration slowly moves by the energy due to conduction or strain, and finally the active layer which is a light emitting region. Is thought to be due to reaching.

The present inventor has made various studies in consideration of the above, and as a result, in order to prevent rapid and slow deterioration of the AlGaInP-based semiconductor light emitting device, propagation of crystal defects to the periphery of the active layer has been considered. Is important to control. And for that, InP
It has been found that it is effective to insert a layer made of a compound semiconductor containing the compound in the cladding layer, and the present invention has been devised.

That is, in order to achieve the above object, the present invention provides an AlGaInP-based semiconductor light emitting device having a structure in which an active layer is sandwiched between an n-type cladding layer and a p-type cladding layer. At least one crystal defect propagation suppressing layer made of a compound semiconductor containing at least InP is inserted into at least one of the cladding layers.

Further, the present invention relates to an optical disc recording and / or reproducing apparatus using an AlGaInP-based semiconductor light-emitting device as a light-emitting device, wherein the AlGaInP-based semiconductor light-emitting device has an active layer formed of an n-type cladding layer and a p-type cladding layer. It has a sandwiched structure, an n-type cladding layer and a p-type cladding layer.
At least one of the mold cladding layers has at least I
At least one crystal defect propagation suppressing layer made of a compound semiconductor containing nP is inserted.

In the present invention, the crystal defect propagation suppressing layer is composed of a superlattice including at least a compound semiconductor layer containing InP, and each layer of the superlattice has a thickness less than a critical thickness, or A single-layer compound semiconductor layer containing at least InP and having a thickness equal to or less than the critical thickness can be used. Some specific examples of the compound semiconductor layer containing at least InP include an InP layer,
InGaAsP layers, InAsP layers, and the like.

In the present invention, when an n-type cladding layer, an active layer and a p-type cladding layer are sequentially laminated on a semiconductor substrate, the AlGaInP-based semiconductor light emitting device has a stripe extending in one direction above the p-type cladding layer. And a crystal defect propagation suppressing layer is inserted into the p-type cladding layer at the same height as the lowermost portion of the stripe portion.

In the present invention constructed as described above, at least one crystal defect propagation suppressing layer made of a compound semiconductor containing at least InP is inserted into at least one of the n-type cladding layer and the p-type cladding layer. Accordingly, mainly by the action of InP included in the crystal defect propagation suppressing layer, propagation of crystal defects from the portion outside the crystal defect propagation suppressing layer as viewed from the active layer to the active layer can be suppressed. .

[0017]

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 shows an AlGaInP-based semiconductor laser according to a first embodiment of the present invention.

As shown in FIG. 1, in the AlGaInP-based semiconductor laser according to the first embodiment, an n-type G
An n-type GaAs buffer layer 2 and an n-type (A
l _x Ga _1-x ) _y In _1-y P cladding layer 3, active layer 4,
p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer 5, p
GaInP intermediate layer 6 and p-type GaAs cap layer 7
Are sequentially laminated. Here, the n-type GaAs substrate 1 has, for example, a (100) plane orientation,
For example, a plane whose main plane is a plane that is off by 5 to 15 ° from the (100) plane is used.

In this case, p-type (Al _x Ga _{1 -x} ) _y In
The upper part of the _1-y P cladding layer 5, the p-type GaInP intermediate layer 6, and the p-type GaAs cap layer 7 have a stripe shape extending in one direction. An n-type GaAs current block layer 8 is buried in both sides of the stripe portion, thereby forming a current confinement structure.

The p-type GaAs cap layer 7 and the n-type Ga
On the As current blocking layer 8, for example, Ti / Pt / Au
A p-side electrode 9 made of an electrode is provided in ohmic contact with the p-type GaAs cap layer 7. On the back surface of the n-type GaAs substrate 1, an n-side electrode 10 made of, for example, an AuGe / Ni electrode is provided in ohmic contact with the n-type GaAs substrate 1.

The active layer 4 is made of, for example, Ga as a well layer.
It has a GaInP / AlGaInP multiple quantum well (MQW) structure in which InP layers and AlGaInP layers as barrier layers are alternately stacked. In addition, n-type (Al _x G
a _1-x ) _y In _1-y P cladding layer 3 and p-type (Al _x
The composition ratios x and y of the Ga _1-x ) _y In _1-y P cladding layer 5 are selected so that these layers lattice-match with the n-type GaAs substrate 1. Specifically, for example, x = 0.7 , Y =
0.5 is chosen.

In the first embodiment, the conventional A
In addition to the above-described configuration similar to the 1GaInP-based semiconductor laser, a p-type (Al _x Ga _1-x ) _y In _1-y P cladding layer 5
A crystal defect propagation suppressing layer 11 is inserted at a position near the active layer 4 in the middle. In this case, the crystal defect propagation suppressing layer 1
1, a p-type InP layer 11a and a p-type G
It has a superlattice structure in which the aP layers 11b are alternately stacked for two periods. Here, since InP and GaP both have a different lattice constant from GaAs, in order to prevent the occurrence of misfit dislocation due to the difference in lattice constant, these p-type InP
Each of the layer 11a and the p-type GaP layer 11b is selected to have a thickness equal to or less than the critical thickness (for example, about 10 nm, which varies depending on the literature). Specifically, the thickness of each of the p-type InP layer 11a and the p-type GaP layer 11b is selected to be, for example, 1.5 nm. In this case, the average composition of the entire crystal defect propagation suppressing layer 11 is In _0.5 Ga _0.5 P.

If the band gap of the crystal defect propagation suppressing layer 11 is smaller than the band gap of the active layer 4,
Since light emission or light absorption loss occurs from the crystal defect propagation suppressing layer 11, for example, a tensile strain is applied to the active layer 4 so that the band gap of the active layer 4 becomes larger than the band gap of the crystal defect propagation suppressing layer 11. It is important to also reduce. In the crystal defect propagation suppressing layer 11, there is a possibility that a mixed crystal may occur near the interface between the p-type InP layer 11a and the p-type GaP layer 11b. However, since the mixed crystal increases the band gap, This mixed crystallization has no adverse effect.

To give an example of the thickness of each semiconductor layer in this AlGaInP-based semiconductor laser, the n-type GaAs buffer layer 2 has a thickness of 0.3 μm and the n-type (Al _x Ga _{1 -x} ) _y I
The n _{1 -y} P cladding layer 3 is 1 μm, the p-type GaInP intermediate layer 6 is 0.1 μm, and the p-type GaAs cap layer 7 is 0.3 μm.
m. The thickness of the p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer 5 between the active layer 4 and the crystal defect propagation suppressing layer 11 is 0.03 μm. p
P-type (Al _x Ga _1-x ) between the p-type GaInP intermediate layer 6
The thickness of the _y In _1-y P cladding layer 5 is 1 μm.

Next, a method of manufacturing the AlGaInP-based semiconductor laser according to the first embodiment configured as described above will be described.

The AlGaInP according to the first embodiment
In order to manufacture a system-based semiconductor laser, first, for example, metalorganic chemical vapor deposition (MOCVD) is performed on an n-type GaAs substrate 1.
The n-type GaAs buffer layer 2 and the n-type (Al _x G
a _{1 -x} ) _y In _{1 -y} P clad layer 3, active layer 4, p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P clad layer 5 of predetermined thickness, crystal defect propagation suppression layer 11, P-type (Al _x
Ga _1-x ) _y In _1-y P cladding layer 5, p-type GaInP
An intermediate layer 6 and a p-type GaAs cap layer 7 are sequentially grown.

Next, a stripe-shaped resist pattern (not shown) extending in one direction is formed on the p-type GaAs cap layer 7 by lithography, and the resist pattern is used as a mask to form a p-type (Al _x Ga _{1-). x} ) _y I
The n _{1 -y} P clad layer 5 is etched by a wet etching method up to a halfway depth in the thickness direction to form a p-type (Al _x G
a _1-x ) _y In _1-y Upper part of P clad layer 5, p-type GaI
The nP intermediate layer 6 and the p-type GaAs cap layer 7 are patterned in a stripe shape. Here, in this wet etching, for example, an etching solution composed of sulfuric acid and pure water is used. Although illustration is omitted, p-type (Al _x Ga _{1 -x} ) _y I
Ga provided at a predetermined depth in the n _{1 -y} P cladding layer 5
Etching is stopped when the InP etching stop layer is exposed, so that a stripe portion having a desired height and shape is formed.

Next, after removing the resist pattern used as a mask in the above-mentioned wet etching, for example, M
The n-type GaAs current block layer 8 is selectively grown by the OCVD method to bury the portions on both sides of the stripe portion.

Next, for example, p-type GaAs is formed by vacuum evaporation.
A p-side electrode 9 is formed on the entire surface of the s cap layer 7 and the n-type GaAs current block layer 8, and an n-side electrode 10 is formed on the back surface of the n-type GaAs substrate 1 in the same manner. Thereby, the target AlGaInP-based semiconductor laser is manufactured.

As described above, according to the first embodiment, the p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer 5 is formed.
The insertion of the crystal defect propagation suppressing layer 11 therein effectively prevents the crystal defects from propagating to the active layer 4 from a portion outside the crystal defect propagation suppressing layer 11 when viewed from the active layer 4. be able to. This makes it possible to prevent the active layer 4 from deteriorating due to a crystal defect while satisfying the requirements of miniaturization, high light output, high-temperature operation, low noise, and the like, and to extend the life.

Next, A according to the second embodiment of the present invention will be described.
An lGaInP-based semiconductor laser will be described.

The AlGaInP according to the second embodiment
In the semiconductor laser, a single p-type InP layer having a thickness equal to or less than a critical thickness (for example, about 10 nm) is used as the crystal defect propagation suppressing layer 11. Specifically, this p
The thickness of the type InP layer 11a is, for example, 1.5 nm. Other points are the same as those of the first embodiment, and the description is omitted.

According to the second embodiment, the same advantages as in the first embodiment can be obtained.

Next, A according to the third embodiment of the present invention will be described.
An lGaInP-based semiconductor laser will be described. FIG. 3 shows this AlGaInP-based semiconductor laser.

As shown in FIG. 3, in the AlGaInP-based semiconductor laser according to the third embodiment, the p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer 5 has a stripe portion. The crystal defect propagation suppressing layer 11 is inserted at the same height as the lower part. The other configuration is the same as that of the first embodiment, and the description is omitted.

The AlGaInP according to the third embodiment
The method of manufacturing a semiconductor laser according to the first embodiment
The same as the method for manufacturing a GaInP-based semiconductor laser, but
In this case, the p-type GaAs cap layer 7 and the p-type GaInP
The intermediate layer 6 and the p-type top of _{(Al x Ga 1-x)} y In 1-y P cladding layer 5 at the time of wet etching for patterning in a stripe shape, a p-type (Al _x Ga
_1-x ) _y In _{1-y The} crystal defect propagation suppressing layer 11 inserted in the P clad layer 5 functions as an etching stop layer,
Etching stops when the crystal defect propagation suppressing layer 11 is exposed. Note that the etching selectivity of the p-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P clad layer 5 with respect to the crystal defect propagation suppressing layer 11 can be made sufficiently large.
For example, an etching selectivity of about 100 can be obtained.

According to the third embodiment, the p-type (Al
_{Since the} crystal defect propagation suppressing layer 11 is inserted in the xGa1 _-x ) _{yIn1 -yP} cladding layer 5, the same advantages as those of the first embodiment can be obtained. Since the propagation suppressing layer 11 can also be used as an etching stop layer in wet etching for forming a stripe portion, an advantage that a step of separately forming an etching stop layer is not required can be obtained.

Next, A according to the fourth embodiment of the present invention will be described.
An lGaInP-based semiconductor laser will be described.

The AlGaInP according to the fourth embodiment
In a system semiconductor laser, a single p-type InP layer having a thickness equal to or less than a critical thickness (for example, about 10 nm) is used as the crystal defect propagation suppressing layer 4. Specifically, the thickness of the p-type InP layer is, for example, 1.5 nm. Other points are the same as in the third embodiment, and a description thereof will be omitted.

According to the fourth embodiment, advantages similar to those of the third embodiment can be obtained.

Next, the above-mentioned first, second, third or fourth
An optical disk reproducing apparatus using an AlGaInP-based semiconductor laser as a light emitting element according to the embodiment will be described. FIG. 4 shows the configuration of the optical disk reproducing apparatus.

As shown in FIG. 4, the optical disk reproducing apparatus includes a semiconductor laser 101 as a light emitting element. As the semiconductor laser 101, the AlGaInP-based semiconductor laser according to the above-described first, second, third or fourth embodiment is used. The optical disk reproducing apparatus also guides the light emitted from the semiconductor laser 101 to the optical disk D, and reflects the light (signal light) reflected by the optical disk D.
A known optical system for reproducing the image, that is, a collimating lens 102, a beam splitter 103, a quarter-wave plate 104, an objective lens 105, a detection lens 106, a signal light detecting light receiving element 107, and a signal light reproducing circuit 108. ing.

In this optical disc reproducing apparatus, the emitted light L of the semiconductor laser 101 is made parallel by the collimator lens 102, and after passing through the beam splitter 103, the degree of polarization is adjusted by the 波長 wavelength plate 104. The light is condensed by the lens 105 and is incident on the optical disk D. Then, the signal light L ′ reflected by the optical disc D is applied to the objective lens 105 and the 波長 wavelength plate 104.
After the light is reflected by the beam splitter 103 through the detection lens 106, the light is incident on the light receiving element 107 for signal light detection, where it is converted into an electric signal.
At 08, the information written on the optical disc D is reproduced.

According to the optical disk reproducing apparatus, the AlG according to the first, second, third or fourth embodiment having a long life is used.
Since the aInP-based semiconductor laser is used as the semiconductor laser 101, the life of the optical disc reproducing apparatus can be extended.

Here, the case where the AlGaInP-based semiconductor laser according to the first, second, third or fourth embodiment is applied to the light emitting element of the optical disk reproducing apparatus has been described. The present invention can be applied not only to the light emitting element of the device, but also to the light emitting element of an optical device such as an optical communication device and the light emitting element of a vehicle-mounted device which needs to operate at a high temperature. .

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 numerical values and structures described in the first, second, third and fourth embodiments are merely examples, and different numerical values and structures may be used as necessary. .

Specifically, in the first embodiment, p
The position where the crystal defect propagation suppressing layer 11 is inserted into the mold (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer 5 can be changed as necessary. The number of repetitions of the p-type InP layer 11a and the p-type GaP layer 11b constituting the crystal defect propagation suppressing layer 11 may be three or more. Furthermore, p-type (Al
_{x Ga 1-x) y In} 1-y P cladding layer crystal defect propagation controlling layer 11 during 5 may be inserted two or more layers.

The first, second, third and fourth embodiments
In the embodiment, the p-type (Al_xGa _1-x)_yIn_1-yP
The crystal defect propagation suppressing layer 11 is inserted into the cladding layer 5
But n-type (Al_xGa_1-x)_yIn_1-yP clad
This crystal defect propagation suppressing layer 11 may be inserted into layer 3.
And p-type (Al_xGa_1-x)_yIn_1-yP clad layer 5
And p-type (Al_xGa_1-x)_yIn_1-yP clad layer
3 may be provided with the crystal defect propagation suppressing layer 11.
No.

In the first, second, third and fourth embodiments, the conductivity types of the substrate and each semiconductor layer may be reversed. Further, a method other than MOCVD, such as molecular beam epitaxy (MBE), may be used to grow each semiconductor layer.

Further, in the first, second, third and fourth embodiments, the present invention is applied to a DH (Double Heterostr
The present invention has been described for the case where the present invention is applied to an AlGaInP-based semiconductor laser having a SCH (Sepa) structure.
rate Confinement Heterostructure) structure AlGaI
Of course, it may be applied to an nP-based semiconductor laser.
It may be applied to a GaInP-based light emitting diode.

[0053]

As described above, according to the present invention, A
According to the lGaInP-based semiconductor light emitting device, at least one of the n-type clad layer and the p-type clad layer is provided with at least one crystal defect propagation suppression layer made of a compound semiconductor containing InP.
Propagation of crystal defects to the active layer from a portion outside the crystal defect propagation suppressing layer when viewed from the active layer can be suppressed, and deterioration of the active layer due to the crystal defects can be prevented. As a result, it is possible to extend the service life while satisfying requirements such as miniaturization, high light output, high-temperature operation, and low noise.

According to the optical disk recording and / or reproducing apparatus of the present invention, the AlGa
By using an InP-based semiconductor light-emitting element as a light-emitting element, a long life can be achieved.

[Brief description of the drawings]

FIG. 1 shows an AlGaIn according to a first embodiment of the present invention.
It is sectional drawing which shows a P-type semiconductor laser.

FIG. 2 shows an AlGaIn according to the first embodiment of the present invention.
It is an expanded sectional view showing the example of the concrete structure of the crystal defect propagation control layer in the P system semiconductor laser.

FIG. 3 shows an AlGaIn according to a third embodiment of the present invention.
It is sectional drawing which shows a P-type semiconductor laser.

FIG. 4 is a schematic diagram showing an optical disc reproducing apparatus using an AlGaInP-based semiconductor laser according to the first, second, third or fourth embodiment of the present invention as a light emitting element.

[Explanation of symbols]

1 ... n-type GaAs substrate, 3 ... n-type (Al _x Ga
_1-x ) _y In _1-y P clad layer, 4 ... active layer, 5
..P-type (Al _x Ga _{1 -x} ) _y In _{1 -y} P cladding layer,
6 ... p-type GaInP intermediate layer, 7 ... p-type GaAs
Cap layer, 8... N-type GaAs current block layer, 9
... p-side electrode, 10 ... n-side electrode, 11 ... crystal defect propagation suppression layer, 11a ... p-type InP layer, 11b
..P-type GaP layer

Claims (10)

[Claims] An AlGaInP-based semiconductor light emitting device having a structure in which an active layer is sandwiched between an n-type cladding layer and a p-type cladding layer, wherein at least one of the n-type cladding layer and the p-type cladding layer has An AlGaInP-based semiconductor light emitting device, wherein at least one crystal defect propagation suppressing layer made of a compound semiconductor containing InP is inserted. 2. The AlGaInP-based semiconductor light emitting device according to claim 1, wherein at least one of said crystal defect propagation suppressing layers is inserted at least in said p-type cladding layer. 3. The crystal defect propagation suppressing layer comprises a superlattice including at least a compound semiconductor layer containing InP, and each layer of the superlattice has a thickness equal to or less than a critical thickness. Item 2. An AlGaInP-based semiconductor light emitting device according to item 1. 4. The Al according to claim 1, wherein the crystal defect propagation suppressing layer is a single layer of a compound semiconductor layer containing at least InP having a thickness equal to or less than a critical thickness.
GaInP-based semiconductor light emitting device. 5. The AlGaInP according to claim 3, wherein the compound semiconductor layer containing at least InP is an InP layer, an InGaAsP layer, or an InAsP layer.
Series semiconductor light emitting device. 6. The AlGaInP-based semiconductor light emitting device according to claim 4, wherein said compound semiconductor layer containing at least InP is an InP layer or an InGaAsP layer. 7. The crystal defect propagation suppressing layer comprises a superlattice in which InP layers and GaP layers each having a thickness equal to or less than a critical thickness are alternately stacked.
An AlGaInP-based semiconductor light-emitting device according to any one of the preceding claims. 8. A p-type cladding layer having a stripe portion extending in one direction above the p-type cladding layer, wherein the crystal defect propagation suppressing layer has the same height as the lowermost portion of the stripe portion in the p-type cladding layer. 2. The AlGaInP-based semiconductor light emitting device according to claim 1, wherein the AlGaInP semiconductor light emitting device is inserted. 9. The active layer is made of GaInP / AlGaIn.
2. A semiconductor device having a P multiple quantum well structure.
An AlGaInP-based semiconductor light-emitting device according to any one of the preceding claims. 10. An optical disk recording and / or reproducing apparatus using an AlGaInP-based semiconductor light-emitting device as a light-emitting device, wherein the AlGaInP-based semiconductor light-emitting device has a structure in which an active layer is sandwiched between an n-type cladding layer and a p-type cladding layer. An optical disc recording and / or recording method, wherein at least one of the n-type cladding layer and the p-type cladding layer has at least one crystal defect propagation suppression layer made of a compound semiconductor containing InP inserted therein. /
Or a playback device.