JP3102431B1 - Optical recording medium - Google Patents

Abstract

[PROBLEMS] To provide a rewritable phase-change optical recording medium which has excellent overwriting durability, has good overwrite characteristics even after being left for a long time, has no occurrence of burst defects and does not lose recording marks. Offer. SOLUTION: An optical recording medium provided with a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer on a substrate in this order,
A layer containing carbon as a main component is provided between the recording layer and the first dielectric layer so as to be in contact with the recording layer, and the recording layer has the following formula (I) Ｉ (Ge _0.5 Te _0.5 ) _x (Sb _0.4 Te _{0.6 ) 1-x} 1-yz} Sb y a z (I) ( wherein, a represents belongs, Ge, Sb, the group 6B of the second period in the periodic table of the elements from group 3A of the sixth period, except for Te elemental And x, y, and z each represent a number and satisfy the following relational expression: 0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.08, z = 0 or 0.2 ≦ x ≦ 0.8, 0 ≦ y ≦ 0.08, 0
<Z ≦ 0.2), and the thickness of the recording layer is 7 nm or more and 35 nm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to
The present invention relates to an optical information recording medium capable of recording, erasing, and reproducing information. In particular, the present invention provides a method for erasing recorded information,
The present invention relates to a rewritable phase-change optical recording medium, such as an optical disk, an optical card, or an optical tape, having a rewritable function and capable of recording an information signal at high speed and high density.

[0002]

2. Description of the Related Art The technology of a conventional rewritable phase-change optical recording medium is as follows. These optical recording media have a recording layer mainly containing tellurium or the like, and at the time of recording, a focused laser light pulse is applied to the crystalline recording layer for a short time to partially melt the recording layer. The melted portion is quenched by thermal diffusion and solidified to form an amorphous recording mark. The light reflectance of this recording mark is lower than that of the crystalline state and can be reproduced optically as a recording signal. At the time of erasing, the recording mark is irradiated with a laser beam and heated to a temperature below the melting point of the recording layer and above the crystallization temperature to crystallize the amorphous recording mark and return to the original unrecorded state. .

[0003] Recording on these rewritable phase-change optical recording media
The material of the layer is Ge_TwoSb_TwoTe _FiveSuch as alloys (N.Yam
ada et al. Proc. Int. Symp. on Optical Memory 1987
 p61-66) are known. These Te alloys are used as a recording layer.
Optical recording media, the crystallization speed is high and the irradiation power is low.
High speed over with one circular beam just by modulating
Lighting is possible.

This recording layer is used as an optical recording medium, for example, on a transparent substrate formed of a polycarbonate resin or the like, a first dielectric layer / recording layer / second dielectric layer / metal reflective layer. There is a four-layer configuration provided in order. The role of the dielectric layer is to prevent deformation and opening of the recording layer at the time of recording, and the role of the reflective layer is to improve signal contrast at the time of reproduction by an optical interference effect. .

[0005] Problems in this rewritable phase change type optical recording medium are as follows. That is, the conventional disk structure has a problem that the amplitude of the reproduced signal (contrast decreases) occurs due to repeated overwriting, and the jitter characteristics deteriorate. Burst defects may occur due to the growth of cracks in the protective film.

Further, the conventional configuration has the following problems. First, if the recorded disk is left for a long time (hereinafter, referred to as an archival), the recording mark may be lost, or the dielectric layer may be separated from the recording layer to cause a burst defect. Also, if a disc on which a signal is already recorded is left for a long time and then overwriting is performed on a track on which a signal is recorded (hereinafter referred to as an overwrite shelf), jitter characteristics deteriorate and an error occurs. There was a problem. For this reason, there was a problem in the storage durability of the disk.

[0007] The above problem becomes particularly remarkable when performing mark length recording, which is high-density recording, instead of conventional pit position recording.

For example, for a structure in which carbon is arranged so as to be in contact with a recording layer, see WO 96/17344.
In the specification. This content is obtained by adding carbon to the second dielectric layer or adding metal or metalloid to carbon. By doing so, the amount of light absorption in the crystalline state in the recording layer is made larger than the amount of light absorption in the amorphous state, and the variation in the size of the recording marks is reduced.
However, this disk configuration has a problem that the above repetitive overwrite characteristics and storage durability are not sufficient.

Japanese Patent Application Laid-Open No. Hei 3-100936 discloses a substrate /
The present invention relates to an optical recording medium in which a dielectric layer / recording layer / carbon layer / dielectric layer is laminated in this order. This is because the sensitivity of the disk can be increased because the carbon layer has a light absorbing property.
However, this configuration has a problem that the above-described problems of the repetitive overwrite characteristics and the storage durability cannot be solved.

Japanese Patent Application Laid-Open No. 2-139283 discloses a substrate / transparent body layer (ZnS or ZnS.C) / carbon layer (10
nm) / recording layer (composition: Ge ₂ Sb ₂ Te ₅ , thickness:
An optical recording medium of 60 nm) / carbon layer (10 nm or less) / transparent layer / reflective layer is disclosed. However, this configuration has a problem that, when edge recording, which is high-density recording, is performed, repetitive overwrite characteristics and storage durability are not sufficient.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rewritable phase-change type optical recording medium which causes little deterioration due to repetitive overwriting, such as deterioration of jitter characteristics, deterioration of contrast and occurrence of burst defects. It is in. Another object of the present invention is to provide a rewritable phase-change optical recording medium having excellent archival and overwrite shelf characteristics.

[0012]

That is, the first aspect of the present invention is as follows.
The invention irradiates light to record, erase,
Reproducible, and recording and erasing of information is performed by a reversible phase change between an amorphous phase and a crystalline phase, and at least a first dielectric layer, a recording layer, and a second dielectric layer are formed on a substrate. , An optical recording medium having a reflective layer in this order, the recording layer and the first layer.
So as to be in contact with the recording layer between the dielectric layers, with a layer containing carbon as a main component, the recording layer is represented by the following formula _{(I) {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x _{} 1-yz Sb y a z} (I) ( wherein, a is indicated Ge, Sb, an element which belongs from the second period to the group 6B from group 3A of the sixth period in the periodic table of the elements except Te, x , Y, and z indicate numbers and satisfy the following relational expressions: 0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.08, z = 0 or 0.2 ≦ x ≦ 0. 8, 0 ≦ y ≦ 0.08, 0
<Z ≦ 0.2).

According to a second aspect of the present invention, information can be recorded, erased and reproduced by irradiating light,
Recording and erasing of information are performed by a reversible phase change between an amorphous phase and a crystalline phase, and at least a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer are provided in this order on a substrate. In the optical recording medium, a layer containing carbon as a main component is provided between the recording layer and the first dielectric layer so as to be in contact with the recording layer, and the carbon is used as a main component between the recording layer and the second dielectric layer. A layer composed mainly of carbon and oxygen, a layer composed mainly of carbon and nitrogen, and a layer selected from layers composed mainly of carbon, oxygen and nitrogen. formula _{(II) {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y a z (II) ( wherein, a is the periodic table, excluding Ge, Sb, and Te Represents elements belonging to groups 3A to 6B in the second to sixth periods, x, y, and z represent numbers, and the following relationship: Meet. 0.2 ≦ x ≦ 0.95,0.01 ≦ y ≦ 0.08, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2).

According to a third aspect of the present invention, information can be recorded, erased, and reproduced by irradiating light, and information recording and erasing can be performed by reversing between an amorphous phase and a crystalline phase. In an optical recording medium having at least a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer in this order on a substrate, the optical recording medium is disposed between the recording layer and the first dielectric layer. A layer mainly composed of carbon is provided so as to be in contact with the recording layer, and a layer selected from a layer mainly composed of germanium nitride is provided between the recording layer and the second dielectric layer; periodic but following formula _{(III) {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y a z (III) ( wherein, a is excluding, Ge, Sb, and Te X, y indicate elements belonging to groups 3A to 6B of the second to sixth periods in the law table; z represents a number, and satisfies the following relationship. 0.2 ≦ x ≦ 0.95,0.01 ≦ y ≦ 0.08, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2) and the thickness of the recording layer is 7 nm.
As described above, the optical recording medium has a thickness of 35 nm or less.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problem to be solved by the present invention, which is caused by repetitive overwriting, that is, the deterioration of jitter characteristics and the reduction of contrast is caused by the repetitive overwriting of the components of the first dielectric layer. Therefore, it is considered that the material seeps into the recording layer. The direct cause of the deterioration of the jitter characteristic due to the overwrite shelf is that the erasing characteristic is deteriorated. The cause of the deterioration of the erasing characteristics is considered to be that the state of the atomic arrangement changes when the recording mark (amorphous phase) is left for a long time, or that the dielectric layer and the recording layer react. Can be

The present inventors have made intensive studies and found that when a carbon layer is provided between the first dielectric layer and the recording layer, deterioration due to repeated overwriting can be improved, and
It has been found that the deterioration of the jitter characteristic due to the overwrite shelf can be improved.

That is, a typical layer configuration of the constituent members of the optical recording medium according to the present invention is such that a first dielectric layer, a carbon layer, a recording layer, a second dielectric layer, and a reflective layer are laminated in this order on a transparent substrate. Or a first dielectric layer, a carbon layer, a recording layer,
It is formed by laminating a carbon layer, a second dielectric layer, and a reflective layer in this order. However, it is not limited to this.

The description will be made in the following order. A preferable material for the first dielectric layer is a film made of a mixture of ZnS and SiO ₂ . Since this material has a small residual stress, burst deterioration due to repeated overwriting is unlikely to occur. In this material, the preferable range of the molar ratio of SiO ₂ is 10 mol% or more and 30 mol% or less. A particularly preferred range is from 15 mol% to 25 mo.
1% or less. In addition, the mixture of ZnS, SiO _2, and carbon has a smaller residual stress in the film and hardly causes deterioration in recording sensitivity, carrier-to-noise ratio (C / N), erasure rate, and the like even when recording and erasing are repeated. It is particularly preferable from this. The thickness of the film is determined by optical conditions, but is preferably from 5 to 500 nm. If the thickness is larger than this, cracks and the like may occur. If the thickness is smaller than this, the substrate is easily damaged by heat due to repeated overwriting, and the repetition characteristics may be deteriorated. A particularly preferred range of the film thickness is from 10 nm to 200 nm.

In the present invention, it is necessary to provide a film containing carbon as a main component between the first dielectric layer and the recording layer described below. In the present invention, the term "main component" means that the component is present in a larger amount than any other component present in the film. By providing this, it is possible to prevent deterioration of jitter due to repetition of overwriting and a decrease in amplitude of a reproduced signal. This is because these films are the first
It is considered that it functions as a barrier layer that prevents the diffusion of the first dielectric layer component from the dielectric layer to the recording layer. Further, by providing a film containing carbon as a main component, deterioration of jitter characteristics due to the overwrite shelf can be improved. It is presumed that the cause of this is that even if the recording layer is left for a long time, a change in the state of the recording layer such as the atomic arrangement and a reaction between the dielectric layer and the recording layer can be prevented.

The thickness of the carbon film is set to 0.5 because of the difficulty in peeling from the first dielectric layer and the optical condition.
It is preferably from 10 nm to 10 nm. When the thickness exceeds 10 nm, it is easy to peel off from the first dielectric layer and the recording layer. On the other hand, when the thickness is less than 0.5 nm, it is difficult to deposit the film to a uniform thickness, and the effect of providing the carbon film may not be obtained. Considering the deposition rate of the carbon film, 0.5 nm
It is particularly preferably at least 5 nm and at most 5 nm. 0.5 nm or more and 4 nm
The following is even more preferable from the viewpoint of the repetition characteristics.

From the viewpoint of the repetition characteristics, the reason why there is a preferable range in the thickness of the carbon layer and the mechanism are considered as follows.

1 and 2 respectively show two laminated samples, that is, No. 2 samples. A: Ge-Sb-Te (7 nm) / C (2
nm) / ZnS-SiO ₂ (93 nm) / substrate (FIG. 1)
And No. B: Ge-Sb-Te (7 nm) / C (5n
m) / ZnS—SiO ₂ (93 nm) / substrate (FIG. 2)
Auger electron spectroscopy (PERKIN ELM
7 is a chart of a depth profile measured by using "PHI-670" manufactured by ER Corporation). The horizontal axis represents the time during which the sample was excavated from the surface while irradiating with Ar ions and sputter etching, and corresponds to the depth from the sample surface, in other words, the thickness of the layer. Corresponds to the peak intensity of Auger electrons detected from the elements of the above. That is, it represents the ratio of the elements present corresponding to the thickness from the surface. FIG.
Is No. The sample A is the boundary between the Ge—Sb—Te layer and the carbon layer, the center in the thickness direction of the carbon layer, the carbon layer and the ZnS—SiO
Sputter time 1.0 min, 1.8 at the boundary between _two layers
FIG. 4 is a chart of the KLL Auger electron spectrum of carbon at 3.2 minutes and 3.2 minutes. Sample B is Ge-Sb-
Carbon at sputtering time of 1.4 minutes, 3.8 minutes, and 6.4 minutes corresponding to the boundary between the Te layer and the carbon layer, the center in the thickness direction of the carbon layer, and the boundary between the carbon layer and the ZnS—SiO ₂ layer. 5 is a chart of a KLL Auger electron spectrum. 3 and 4 that the shapes of the three spectra are different from each other. The spectrum from the center in the thickness direction of the carbon layer in each figure is identified as graphite. In the spectrum from the boundary between the carbon layer and the ZnS—SiO ₂ layer, a shoulder peak attributed to carbide is 266 eV.
This is observed in the vicinity, and it is understood that carbon is chemically bonded to the ZnS—SiO ₂ layer. The spectrum from the boundary between the Ge—Sb—Te layer and the carbon layer is intermediate between the spectrum from the center of the carbon layer and the spectrum from the boundary between the carbon layer and the ZnS—SiO ₂ layer. -Sb-T
It can be seen that there is an interaction close to a chemical bond with e. FIGS. 5 and 6 show the spectra of each carbon in FIGS. 1 and 2, the spectrum from the boundary between the Ge—Sb—Te layer and the carbon layer, the spectrum from the center in the thickness direction of the carbon layer, and the carbon layer and ZnS—SiO 2. ₄ shows a chart decomposed into three components of a spectrum from a boundary between _two layers. From the comparison between FIG. 5 and FIG. B sample was No. It can be seen that the component of the spectrum from the center of the carbon layer, that is, the layer of the graphite component is mainly thicker than the sample of A.

From the above results, the carbon layer is in contact with Ge
Due to the relatively tightly bound by -sb-Te recording layer and the ZnS-SiO ₂ dielectric layer and a chemical bond or interaction close to it, such as peeling at the interface is considered unlikely to occur during repeated recording. However, when the thickness of the carbon layer is increased, the graphite component layer having a low strength near the center in the thickness direction is increased in thickness, so that it is considered that this portion is easily broken at the time of repetition and a burst error is likely to occur.

The carbon layer is composed of a Ge—Sb—Te recording layer and ZnS
Due to the relatively tightly bound to -SiO ₂ dielectric layer,
Delamination during long-term storage is less likely to occur, which is thought to contribute to enhancing long-term storage stability.

When the carbon film is formed by sputtering, the introduced gas may be a mixture of hydrogen as well as a rare gas such as Ar gas. Further, other materials may be mixed, but in order to obtain good characteristics, it is preferable that carbon is contained in a proportion of 60 mol% or more.

In the first invention of the present invention, when a layer mainly composed of carbon is provided only between the first protective layer and the recording layer, the composition of the recording layer falls within the range of the following formula (I). It is necessary. _{{(Ge 0.5 Te 0.5) x} (Sb 0.4 Te 0.6) 1-x} in _{1-yz Sb y A z (} I) wherein, A is, Ge, Sb, from the second period in the Periodic Table of Elements except Te Elements belonging to Group 3A to Group 6B in the sixth period, that is, Al, Si, Sc, Ti, V, Cr,
Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge,
Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, C
d, In, Sn, La, Hf, Ta, W, Re, Ir,
It indicates at least one selected from Pt, Au, Tl, and Pb, x, y, and z indicate numbers and satisfy the following relational expression.

0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.08, z = 0 or 0.2 ≦ x ≦ 0.8, 0 ≦ y ≦ 0.08, 0
<Z ≦ 0.2.

When x <0.2, the contrast between the crystalline phase and the amorphous phase is too small to obtain a sufficient signal intensity. When x> 0.8, the crystallization speed becomes slow, and The characteristics deteriorate, the linear velocity is 5 m / s or more, and the shortest mark length
Under conditions of 7 μm or less, direct overwriting becomes difficult.

When z = 0 and y <0.01, the stability of the amorphous is low, and the archival characteristics are poor. If y> 0.08, the initial erasing characteristics deteriorate and the overwrite shelf deteriorates. When z> 0.2, the crystallization speed is reduced, the erasing characteristics are deteriorated, and it becomes difficult to perform direct overwriting or phase separation under the condition that the linear velocity is 5 m / s or more and the shortest mark length is 0.7 μm or less. , The repetition characteristics are greatly deteriorated, and the overwrite shelf is deteriorated. When y = 0 and z = 0, the stability of the amorphous is low and the archival characteristics are deteriorated.

In the second aspect of the present invention, a film containing carbon as a main component is used on the substrate side of the recording layer, and carbon, carbon and oxygen, carbon and nitrogen, or carbon and carbon is formed on the reflective layer side of the recording layer. When any one of the films containing nitrogen and oxygen as main components is used, the crystallization speed of the recording layer becomes higher, and the necessary composition range is the range of the following formula (II). _{{(Ge 0.5 Te 0.5) x} (Sb 0.4 Te 0.6) 1-x} in _{1-yz Sb y A z (} II) wherein, A is, Ge, Sb, from the second period in the Periodic Table of Elements except Te Elements belonging to Group 6A to Group 6B in the sixth period, ie, Al, Si, Sc, Ti, V, C
r, Mn, Fe, Co, Ni, Cu, Zn, Ga, G
e, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag,
Cd, In, Sn, La, Hf, Ta, W, Re, I
At least one selected from r, Pt, Au, Tl, and Pb is shown, x, y, and z are numbers and satisfy the following relational expression.

0.2 ≦ x ≦ 0.95, 0.01 ≦ y ≦
0.08, z = 0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2.

When x <0.2, the contrast is too small to obtain a sufficient signal intensity, and when x> 0.95, the crystallization speed is reduced, the erasing characteristics are deteriorated, and the linear velocity is 5 m. / S and the shortest mark length of 0.7 μm or less, direct overwriting becomes difficult. When z = 0 and y <0.01, the stability of the amorphous is low, and the archival characteristics are poor. When y> 0.08, overwriting after long-term storage becomes difficult. z = 0
In this case, the range of y is 0.02 ≦ y ≦ 0.08. z
If> 0.2, the crystallization speed becomes slow, the erasing characteristics deteriorate, and direct overwriting becomes difficult under the condition that the linear velocity is 5 m / s or more and the shortest mark length is 0.7 μm or less.

In the third aspect of the present invention, when a film containing carbon as a main component is used on the substrate side of the recording layer and any of films containing germanium nitride as a main component is used on the reflection layer side of the recording layer, Since the crystallization speed of the recording layer is faster,
The necessary composition range is the range of the following formula (III). _{{(Ge 0.5 Te 0.5) x} (Sb 0.4 Te 0.6) 1-x} in _{1-yz Sb y A z (} III) wherein, A is, Ge, Sb, from the second period in the Periodic Table of Elements except Te Elements belonging to Group 6A to Group 6B in the sixth period, ie, Al, Si, Sc, Ti, V, C
r, Mn, Fe, Co, Ni, Cu, Zn, Ga, G
e, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag,
Cd, In, Sn, La, Hf, Ta, W, Re, I
At least one selected from r, Pt, Au, Tl, and Pb is shown, x, y, and z are numbers and satisfy the following relational expression.

0.2 ≦ x ≦ 0.95, 0.01 ≦ y ≦
0.08, z = 0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2.

When x <0.2, the contrast becomes too small to obtain a sufficient signal intensity. When x> 0.95, the crystallization speed becomes slow, the erasing characteristics deteriorate, and the linear velocity becomes 5 m. / S and the shortest mark length of 0.7 μm or less, direct overwriting becomes difficult. When z = 0 and y <0.01, the stability of the amorphous is low, and the archival characteristics are poor. When y> 0.08, overwriting after long-term storage becomes difficult. z = 0
In this case, the preferable range of y is 0.02 ≦ y0.08. When z> 0.2, the crystallization speed is reduced, the erasing characteristics are deteriorated, the linear velocity is 5 m / s or more, and the shortest mark length is 0.7.
Direct overwrite becomes difficult under the condition of μm or less.

The relationship between the composition range of the recording layer and the recording characteristics is described in DVD Specifications for Rewritable Disc / Part.
1. The above tendency appears more clearly in the disc and evaluation method according to the standard described in Physical Specifications Ver. 1.0.

The recording layer of the present invention preferably has a thickness of 5 nm or more and 40 nm or less. If the thickness of the recording layer is smaller than the above, sufficient contrast between the crystal part and the amorphous part cannot be obtained, or the recording characteristics are significantly deteriorated due to repeated overwriting. If the thickness of the recording layer is larger than the above, the recording layer is likely to move due to repeated overwriting, and the jitter is greatly deteriorated.
In particular, when mark length recording is adopted, the recording layer is more likely to move due to recording and erasing than when pit position recording is used.To prevent this, it is necessary to further increase the cooling of the recording layer during recording. The thickness of the recording layer is 7 nm
It is in the range of ３５35 nm. More preferably, 7 nm to 25
nm.

The material of the second dielectric layer of the present invention may be the same as that of the first dielectric layer,
Different materials may be used. Thickness is 2nm or more and 50n
m or less is preferable. If the thickness of the second dielectric layer is smaller than the above, defects such as cracks occur, and the durability of the second dielectric layer is undesirably reduced. Further, the thickness of the second dielectric layer is
If the thickness is larger than the above, the cooling degree of the recording layer becomes low, which is not preferable. The thickness of the second dielectric layer has a more direct effect on the cooling of the recording layer, and in order to obtain better erasure characteristics and repetition durability, and particularly to achieve good recording in the case of mark length recording. -In order to obtain erasing characteristics, 30 nm or less is more effective. Since it absorbs light and can be efficiently used as thermal energy for recording and erasing, it is also preferable to be formed from a non-transparent material. For example,
The mixture of ZnS, SiO _2, and carbon has low residual stress in the film and hardly causes deterioration in recording sensitivity, carrier-to-noise ratio (C / N), erasure rate, etc., even when recording and erasing are repeated, and overwriting. It is also preferable because deterioration of jitter characteristics in the shelf can be further improved.

A layer mainly composed of carbon, a film mainly composed of carbon and oxygen, or a layer mainly composed of carbon, oxygen and nitrogen is provided between the recording layer and the second dielectric layer. It is also preferable to provide them. By doing so, the deterioration of the jitter characteristic due to the overwrite shelf can be further improved, and the crystallization speed can be improved. A preferred range for the thickness of this layer is 0.5 nm or more and 10 nm or less. If the thickness exceeds 10 nm, it is easy to peel off from the second dielectric layer and the recording layer. On the other hand, if the thickness is less than 0.5 nm, it is difficult to deposit the film to a uniform thickness, and the effect of providing these layers may not be obtained. In consideration of the deposition rate and the like, the thickness is particularly preferably 0.5 nm or more and 5 nm or less.

Similarly, it is preferable to provide a layer containing germanium nitride as a main component between the recording layer and the second dielectric layer. By doing so, the deterioration of the jitter characteristic due to the overwrite shelf can be further improved, and the crystallization speed can be improved. The preferred range of the thickness of this layer is
It is 0.5 nm or more and 50 nm or less. If the thickness is smaller than this, it is difficult to deposit the film to a uniform thickness. On the other hand, if the thickness is larger than this, the cooling rate of the recording layer decreases, and as a result, the overwrite durability may be repeatedly deteriorated.
A more preferable range of the thickness is 0.5 nm or more and 20 nm.
It is as follows.

The range of x when germanium nitride is described as GeNx is preferably in the range of 0.4 ≦ x ≦ 1.3. When x <0.4, the recording characteristics may be significantly deteriorated due to repeated overwriting. If x> 1.3, the overwrite shelf characteristics may not be sufficiently improved, cracks may easily occur, and storage durability may not be sufficient.

Examples of the material for the reflective layer include metals and alloys having light reflectivity, and mixtures of metals and metal compounds. Specifically, a metal having a high reflectivity, such as Al, Au, Ag, or Cu, an alloy containing the same as a main component, Al, S
Metal compounds such as nitrides, oxides, and chalcogenides such as i are preferable. Metals such as Al, Au, and Ag, and alloys containing these as main components are particularly preferable because of their high light reflectivity and high thermal conductivity. In particular, an alloy containing Al or Ag as a main component is preferable because the price of the material can be reduced. The thickness of the reflective layer is generally about 10 nm or more and 300 nm or less. The thickness is preferably 30 nm or more and 200 nm or less because the recording sensitivity is high and the reproduction signal intensity can be increased.

Next, a method for manufacturing the optical recording medium of the present invention will be described. As a method for forming the first dielectric layer, the carbon layer, the recording layer, the second dielectric layer, the reflective layer, and the like on the substrate, a thin film forming method in a vacuum, for example, a vacuum deposition method, an ion plating method, a sputtering method, Law. In particular, the sputtering method is preferable because the composition and the film thickness can be easily controlled. The thickness of the recording layer or the like to be formed can be easily controlled by monitoring the deposited state with a quartz crystal film thickness meter or the like.

After the reflective layer is formed within a range that does not significantly impair the effects of the present invention, a dielectric layer of ZnS, SiO ₂ , ZnS—SiO ₂ , etc. A protective layer such as a resin may be provided as necessary.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (Analysis and Measurement Method) The compositions of the reflective layer and the recording layer were confirmed by ICP emission analysis (manufactured by Seiko Instruments Inc.).
The film thickness during the formation of the recording layer, the dielectric layer, and the reflective layer was monitored with a quartz crystal film thickness meter. The thickness of each layer was measured by observing the cross section with a scanning or transmission electron microscope. In the optical recording medium formed by sputtering, the recording layer on the entire surface of the disk was crystallized and initialized with a beam of a semiconductor laser having a wavelength of 830 nm before recording.

Examples 1 to 24 and Comparative Examples 1 to 20
In, recording characteristics were measured under the following condition 1. The recording characteristics of Example 25 were measured under the condition 2.

Condition 1: A random pattern of 8/16 modulation was formed on a groove by using an optical head having a numerical aperture of an objective lens of 0.6 and a wavelength of a semiconductor laser of 680 nm under a condition of a linear velocity of 6 m / sec. Overwriting was performed 100,000 times by recording. At this time, the recording laser waveform used was a general multi-pulse. The window width at this time was 34 ns (the shortest mark length in this case was 0.6 ns).
3 μm). Recording power and erasing power were optimized for each disk. Jitter was measured by a time interval analyzer. The decrease in the amplitude of the signal waveform and the presence or absence of a burst defect were observed with an oscilloscope.

Condition 2: 8/16 modulation random pattern mark using an optical head having a numerical aperture of 0.6 of an objective lens and a wavelength of 660 nm of a semiconductor laser under the condition that the groove has a linear velocity of 8.2 m / sec. A long record was made. At this time, the recording laser waveform used was a general multi-pulse. The window width at this time was 17 ns (the shortest mark length in this case was 0.42 μm). Recording power and erasing power were optimized for each disk. Jitter was measured by a time interval analyzer.

(Example 1) thickness 0.6 mm, diameter 12c
m, 1.48 μm pitch (land width 0.74 μm, glue
Polycarbonate with spiral groove of groove width 0.74μm)
While rotating the substrate made of carbonate at 30 revolutions per minute,
Went putter. First, 1 × 10^-3Pa
And then exhausted with SiO 2 in a 0.2 Pa Ar gas atmosphere.
_Two Is sputtered with ZnS added with 20 mol%
A first dielectric layer having a thickness of 95 nm was formed on the first dielectric layer. Next, carbon
The target was sputtered to form a carbon layer of 2 nm. Continued
Then, an alloy target made of Ge, Sb, and Te is sputtered.
To a thickness of 20 nm and a composition Ge_17.1Sb_27.6Te_55.3
[That is, ｛(Ge_0.5Te_0.5)_0.349(Sb_0.4Te
_0.6)_0.651｝_0.979Sb_0.021Was obtained. further
The same ZnS.SiO as the first dielectric layer as the second dielectric layer
_TwoIs sputtered to form a film having a thickness of 16 nm.
_97.5Cr_2.5Sputtering alloy to reflect 150nm film
A layer was formed. This disk was taken out of the vacuum container
Then, on this reflective layer, acrylic UV curable resin (Dainippon
Ink Co., Ltd. SD-101) is spin-coated and ultraviolet
Cured by radiation to form a 3 μm thick resin layer,
Next, use a screen printing machine to apply a slow-acting UV curable resin.
And irradiating it with ultraviolet light.
The optical recording medium of the present invention was obtained by laminating the two recording media.

The jitter after overwriting 100,000 times was measured and found to be 3.09 ns, which is 9% of the window width, which is sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was measured to be 2.5 × 10 ⁻⁵ . In the recorded state, it was dried (in the air without humidity adjustment such as humidification) and left at 80 ° C. for 100 hours. Thereafter, when the byte error rate of the same part was measured, it was 3.0.
There was almost no change at ^10-5 . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 4.1 × 10 ⁻⁵ and hardly changed. The jitter at this time was 3.40 ns, which was a good value of 10% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after standing were 1.5 × 10 ⁻⁵ and 2.0 × 10 ⁻⁵ , respectively, and there was almost no change, and no burst defects due to peeling were observed.

Example 2 The composition of the reflective layer was changed to Al _98.0 Hf.
An optical recording medium was obtained in the same manner as in Example 1 except that _1.8 Pd _0.2 was used. When the same measurement as in Example 1 was performed, almost the same result was obtained.

Example 3 The composition of the recording layer was changed to (Ge ₂ Sb ₂
Te ₅ ) _0.99 Nb _0.01 [that is, ｛(Ge _0.5 T
e _0.5 ) _0.444 (Sb _0.4 Te _0.6 ) _0.556 ｝ _0.990 Nb
_0.010 ], and a disk was produced in the same manner as in Example 1. The jitter after overwriting 100,000 times was 3.41 ns.
%, Which was sufficiently small for practical use. The amplitude of the signal is 1
There was almost no change compared to the amplitude of the signal after 0 overwrites, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was 1.5 × 10 ⁻⁵ . In the recorded state, the substrate was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. After this,
When the byte error rate of the same part was measured,
There was almost no change at 5 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.1 × 10 ⁻⁵ . The jitter at this time was 3.83 ns, which was a good value of 10% of the window width.

In place of Nb, Al, Si, Sc,
Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Z
n, Ga, Ge, Y, Zr, Mo, Ru, Rh, Pd,
Ag, Cd, In, Sn, La, Hf, Ta, W, R
Even when e, Ir, Pt, Au, Tl, and Pb are used,
Almost similar results were obtained.

Example 4 The composition of the second dielectric layer was changed to Δ (Zn) by simultaneously sputtering a ZnS target to which 20 mol% of SiO ₂ was added and a carbon target.
S) ₈₀ (except that the _{SiO 2) 2 0} 90 C} 10 is Example 1
A disk was produced in the same manner as described above.

When the jitter after overwriting 100,000 times was measured, it was 3.75, which was confirmed to be 11% of the window width and sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was 1.5 × 10 ⁻⁵ . In the recorded state, the substrate was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. After that, when the byte error rate of the same part was measured, it was 1.8.
There was almost no change at ^10-5 . Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.1 × 10 ⁻⁵ . The jitter at this time was 3.05 ns, which was a good value of 9% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after standing were 2.5 × 10 ⁻⁵ and 2.8 × 10 ⁻⁵ , respectively, and there was almost no change, and no burst defect due to peeling was observed.

(Example 5) A carbon film having a thickness of 2 nm was inserted between the recording layer and the second dielectric layer, and the composition of the recording layer was changed to Ge _16.2
Sb _30.8 Te _53.2 [that is, _Δ (Ge _0.5 Te _0.5 )
_0.345 except that the _{(Sb 0.4 Te 0. 6) 0.655} } 0.941 Sb 0.059] was prepared disks in the same manner as in Example 1.

The jitter measured after overwriting 100,000 times was 3.05 ns, which was 9% of the window width.
It was confirmed that it was small enough for practical use. The signal amplitude is 10
There was almost no change in the amplitude of the signal after the overwrite, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was 0.8 × 10 ⁻⁵ . In the recorded state, the substrate was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. Thereafter, when the byte error rate of the same part was measured,
There was almost no change at ^10-5 . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 0.8 × 10 ⁻⁵ and hardly changed. The jitter at this time was 2.55 ns, a good value of 7.5% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after the standing were 1.0 × 10 ⁻⁵ and 1.2 × 10 ⁻⁵ , respectively, and there was almost no change, and no burst defect due to peeling was observed.

(Example 6) As conditions for sputtering a carbon target, a pressure of 0.2 Pa, argon: oxygen =
A disk was formed in the same manner as in Example 1 except that sputtering was performed with a 9: 1 mixed gas, and a film having a thickness of 2 nm and containing carbon and oxygen as main components was inserted between the recording layer and the second dielectric layer. Was prepared.

When the jitter after 100,000 times of overwriting was measured, it was 3.39 ns.
%, Which was sufficiently small for practical use. The amplitude of the signal is 1
There was almost no change compared to the amplitude of the signal after 0 overwrites, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was 1.0 × 10 ⁻⁵ . In the recorded state, the substrate was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. After this,
When the byte error rate of the same part was measured,
There was almost no change to 0 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 0.9 × 10 ⁻⁵ and hardly changed. The jitter at this time was 2.71 ns, which was a good value of 8.0% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after
The values were 2.2 × 10 ⁻⁵ and 2.5 × 10 ⁻⁵ , respectively, and there was almost no change, and no burst defect due to peeling was observed.

Example 7 Conditions for sputtering a carbon target were a pressure of 0.2 Pa, argon: oxygen:
Sputtering was performed with a mixed gas of nitrogen = 8: 1: 1, and the thickness was 2
A disc was produced in the same manner as in Example 1 except that a film mainly composed of carbon, oxygen and nitrogen of nm was inserted between the recording layer and the second dielectric layer.

When the jitter after 100,000 times of overwriting was measured, it was 3.41 ns.
%, Which was sufficiently small for practical use. The amplitude of the signal is 1
There was almost no change compared to the amplitude of the signal after 0 overwrites, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was measured to be 2.5 × 10 ⁻⁵ . In the recorded state, the substrate was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. After this,
The byte error rate of the same part was measured.
There was almost no change at 5 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.5 × 10 ⁻⁵ . The jitter at this time was 2.72 ns, which was a good value of 8.0% of the window width.

Example 8 A disk was manufactured in the same manner as in Example 1 except that the thickness of the carbon layer was changed to 0.5 nm. 1
When the jitter after overwriting 100,000 times was measured,
It was confirmed that the window was 3.77, which was 11% of the width, which was sufficiently small for practical use. The signal amplitude hardly changed compared to the signal amplitude after overwriting 10 times, and no burst defect was observed.

The recording was performed once on this disk, and the byte error rate at that time was measured.
^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. After that, when the byte error rate of the same portion was measured, it was almost unchanged at 3.5 × 10 ⁻⁵ .
Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.0 × 10 ⁻⁵ . The jitter at this time is 2.75n
s, which was a good value of 8.0% of the window width.

Example 9 A disk was manufactured in the same manner as in Example 1 except that the thickness of the carbon layer was changed to 1.0 nm. 1
When the jitter after overwriting 100,000 times was measured,
3.10, that is, 9.1% of the width of the window, was confirmed to be sufficiently small for practical use. The signal amplitude hardly changed compared to the signal amplitude after overwriting 10 times, and no burst defect was observed.

Further, recording was performed once on this disk, and the byte error rate at that time was measured.
^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. After that, when the byte error rate of the same portion was measured, it was almost unchanged at 3.5 × 10 ⁻⁵ .
Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 3.1 × 10 ^-5 and hardly changed. The jitter at this time is 2.82n
s, which was a good value of 8.2% of the window width.

Example 10 The thickness of the carbon layer was 1.5 nm.
A disk was produced in the same manner as in Example 1 except for the above.
Jitter was measured after overwriting 100,000 times.
It was confirmed that the window was 3.05 and 8.9% of the width was sufficiently small for practical use. The signal amplitude hardly changed compared to the signal amplitude after overwriting 10 times, and no burst defect was observed.

The recording was performed once on this disk, and the byte error rate at that time was measured.
^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 1.5 × 10 ⁻⁵ .
Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.0 × 10 ⁻⁵ . The jitter at this time is 2.65n
s, which is a good value of 7.7% of the window width.

Example 11 A disk was manufactured in the same manner as in Example 1 except that the thickness of the carbon layer was changed to 5 nm. When the signal waveform was observed after overwriting 1,000 times, what was seen as a burst defect was recognized.

The recording was performed once on this disk, and the byte error rate at that time was measured.
^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. After that, when the byte error rate of the same portion was measured, it was almost unchanged at 3.5 × 10 ⁻⁵ .
Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 3.5 × 10 ⁻⁵ and hardly changed. The jitter at this time is 2.90 n
s, which was a good value of 8.5% of the window width.

Example 12 The composition of the recording layer was Ge _35.7 S
b _12.6 Te _51.7 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 728
(Sb _0.4 Te _0.6 ) A disk was manufactured in the same manner as in Example 1 _{except that 0.272} ｝ _0.981 Sb _0.019 ] was used.

Recording was performed once on this disk, and the byte error rate at that time was 1.1 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was almost unchanged at 1.4 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was almost unchanged at 2.1 × 10 ⁻⁵ . The jitter at this time was 2.73 ns, a favorable value of 8.0% of the window width.

(Example 13) The composition of the recording layer was Ge _33.9 S
b _15.6 Te _50.5 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 710
(Sb _0.4 Te _0.6 ) _0.290 ｝ _0.955 Sb _0.045 ], a first dielectric layer, a carbon layer, a recording layer, a carbon layer, a second dielectric layer,
The thickness of the reflection layer is 100 nm, 2 nm, and 15 n, respectively.
A disk having a six-layer structure was produced in the same manner as in Example 5, except that the thicknesses were set to m, 2 nm, 18 nm, and 150 nm.

Recording was performed once on this disk, and the byte error rate at that time was 2.0 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was almost unchanged at 2.8 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 1.0 × 10 ⁻⁴ and there was no practical problem. The jitter at this time was 3.4 ns, which was a favorable value of 10.0% of the window width.

Example 14 The composition of the recording layer was Ge _34.6 S
b _13.5 Te _51.9 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 706
(Sb _0.4 Te _0.6 ) A disk was prepared in the same manner as in Example 13, except that _0.294 { _0.980 Sb _0.020 ].

Recording was performed once on this disk, and the byte error rate at that time was measured to be 7.05 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. After that, when the byte error rate of the same portion was measured, it was almost unchanged at 1.00 × 10 ⁻⁴ .
Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 1.27 × 10 ^{−4, which} is practically no problem. The jitter at this time was 3.4 ns, which was a favorable value of 10.0% of the window width.

Example 15 The composition of the recording layer was Ge _37.0 S
b _11.0 Te _52.0 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 747
A disc was prepared in the same manner as in Example 13, except that (Sb _0.4 Te _0.6 ) _0.253 { _0.990 Sb _0.010 ].

Recording was performed once on this disk, and the byte error rate at that time was 1.78 × 10 ⁻⁴ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. Thereafter, when the byte error rate of the same portion was measured, it was confirmed that there was no practical problem of 3.15 × 10 ⁻⁴ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 4.14 × 10 ^{−4, which} is practically no problem. The jitter at this time is 3.9
ns, which is 11.3% of the window width.

Example 16 The composition of the recording layer was Ge _40.4 S
_b8.4 Te _51.2 [that is, ｛(Ge _0.5 Te _0.5 )
Except for using _{0.8 18 (Sb 0.4 Te 0.6)} 0.182} 0.988 Sb 0.012], to prepare a disk in the same manner as in Example 13.

Recording was performed once on this disk, and the byte error rate at that time was 1.57 × 10 ⁻³ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. Thereafter, when the byte error rate of the same portion was measured, it was 1.9 × 10 ⁻³ . Further, when this portion was overwritten once, the byte error rate was 1.39 × 10 ^−3, and the error rate before and after overwriting did not deteriorate. The jitter at this time is
4.5 ns, which was 13.1% of the window width.

(Embodiment 17) Recording layer in Embodiment 5
The carbon layer between the first dielectric layer and the second dielectric layer is _1.2
A disk similar to that of Example 5 was prepared except that the disk was replaced with
did. The ratio of Ge (germanium) to N (nitrogen)
(X = 1.2) is measured using Rutherford backscattering method.
Specified. GeN_1.2Is a mixed gas atmosphere of argon and nitrogen
Made by sputtering a Ge target in the air
Made.

When the jitter after 100,000 times of overwriting was measured, it was confirmed that it was 3.12 ns, 9.1% of the window width, which was sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude after 10 times of overwriting, and no burst defect was observed.

Recording was performed once on this disk, and the byte error rate at that time was 1.4 × 10 ^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 1.5 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 1.6 × 10 ⁻⁵ and hardly changed. The jitter at this time was 2.7 ns, which was a good value of 8.0% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after the standing were 1.8 × 10 ⁻⁵ and 1.9 × 10 ⁻⁵ , respectively, and there was almost no change. Also, no burst defect due to peeling was observed.

[0083] (Example 18) a first dielectric layer, carbon layer, recording layer, a layer made of GeN _1.2, the second dielectric layer, the layer structure of the reflective layer, each layer of the thickness, respectively, 100 nm, 2n
A disc similar to that of Example 13 was produced except that m, 15 nm, 2 nm, 18 nm, and 150 nm were used.

Recording was performed once on this disk, and the byte error rate at that time was 1.0 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 1.0 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 1.8 × 10 ⁻⁵ and there was no practical problem. The jitter at this time was 3.0 ns, which was a good value of 8.8% of the window width.

(Example 19) The composition of the recording layer was changed to that of Example 14.
A disc having the same layer structure as that of Example 18 was produced.

Recording was performed once on this disk, and the byte error rate at that time was measured to be 6.0 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was almost unchanged at 8.0 × 10 ⁻⁴ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 1.0 × 10 ⁻⁴ and there was no practical problem. The jitter at this time was 3.2 ns, which was a good value of 9.4% of the window width. (Example 20) The composition of the recording layer was the same as that of Example 15, and the layer configuration was Example. A disc identical to No. 18 was produced.

Recording was performed once on this disk, and the byte error rate at that time was 1.81 × 10 ⁻⁴ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. Thereafter, when the byte error rate of the same portion was measured, it was confirmed that there was no practical problem of 2.12 × 10 ⁻⁴ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 3.22 × 10 ^{−4, which} is practically no problem. The jitter at this time is 3.6
ns, which was 10.6% of the window width.

Example 21 The composition of the recording layer was changed to that of Example 16.
A disc having the same layer structure as that of Example 18 was produced.

Recording was performed once on this disk, and the byte error rate at that time was 1.18 × 10 ⁻³ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state. Thereafter, when the byte error rate of the same portion was measured, it was 1.50 × 10 ⁻³ . Furthermore, when this portion was overwritten once, the byte error rate was 1.41 × 10 ^−3, and the error rate before and after overwriting did not deteriorate. The jitter at this time is
4.4 ns, 12.9% of the window width.

Example 22 A disk was manufactured in the same manner as in Example 17 except that GeN _0.7 was used as the germanium nitride between the recording layer and the second dielectric layer.

The jitter after overwriting 100,000 times was measured to be 3.40 ns, 10.0% of the window width.
It was confirmed that it was small enough for practical use. The signal amplitude is 10
There is almost no change compared to the amplitude after overwriting
No burst defects were seen.

Recording was performed once on this disk, and the byte error rate at that time was 2.5 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, there was almost no change of 2.4 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 2.6 × 10 ^-5 and hardly changed. The jitter at this time was 2.8 ns, which was a good value of 8.2% of the window width. Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after standing were 2.8 × 10 ⁻⁵ and 3.1 × 10 ⁻⁵ , respectively, and there was almost no change. Also, no burst defect due to peeling was observed.

Example 23 A disk was manufactured in the same manner as in Example 17 except that germanium nitride between the recording layer and the second dielectric layer was changed to GeN _0.3 .

When the repetitive overwrite characteristics of this disk were evaluated, a defect likely to be a burst defect was recognized at 3000 times.

Recording was performed once on this disk, and the byte error rate at that time was 3.3 × 10 ^-5 . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was almost unchanged at 3.5 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 4.6 × 10 ^-5 and hardly changed. The jitter at this time was 3.40 ns, a favorable value of 10.0% of the window width.
Further, the same disk was left at 90 ° C. and a relative humidity of 80% for 140 hours. The byte error rates before and after the standing were 4.0 × 10 ⁻⁵ and 4.1 × 10 ⁻⁵ , respectively, and there was almost no change. Also, no burst defect due to peeling was observed.

(Example 24) A disk similar to that of Example 17 was produced except that germanium nitride between the recording layer and the second dielectric layer was changed to GeN _1.33 .

The jitter after overwriting 100,000 times was measured to be 3.40 ns, 10.0% of the window width.
It was confirmed that it was small enough for practical use. The signal amplitude is 10
There is almost no change compared to the amplitude after overwriting
No burst defects were seen.

Recording was performed once on this disk, and the byte error rate at that time was 4.9 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was almost unchanged at 5.5 × 10 ⁻⁵ . Further, when this portion was overwritten once, the byte error rate was slightly deteriorated to 3.1 × 10 ⁻⁴ . The jitter at this time is 4.08 ns, and the window width is 1
2.0%. Furthermore, the same disk was heated at 90 ° C,
It was left for 140 hours under the condition of a relative humidity of 80%. The byte error rates before and after leaving are 1.8 × 10 ^-5 respectively.
And 3.1 × 10 ⁻⁴ , and there was almost no change. Also, no burst defects were found. (Example 25) Thickness 0.6 mm, diameter 12 cm, 1.2
Sputtering was performed while rotating a polycarbonate substrate with a spiral groove having a pitch of 3 μm (land width 0.615 μm, groove width 0.615 μm) at 30 revolutions per minute. First, the inside of the vacuum vessel is evacuated to 1 × 10 ^-3 Pa, and then SiO 2 is evacuated in an Ar gas atmosphere of 2 × 10 ^-1 Pa.
ZnS to which ₂ mol% was added was sputtered to form a first dielectric layer having a thickness of 92 nm on the substrate. Next, a carbon target was sputtered to form a carbon layer having a thickness of 2 nm. Subsequently, an alloy target made of Ge, Sb, and Te is sputtered to have a thickness of 12 nm and a composition of Ge _27.6 Sb _18.5.
Te _53.9 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 558 (Sb
_0.4 Te _0.6 ) _0.442 { _0.99 Sb _0.01 ].
Further, a carbon target was sputtered to produce a layer of carbon having a thickness of 2 nm. As the second dielectric layer, the same ZnS.SiO ₂ as that of the first dielectric layer was sputtered to form a 23 nm film, and an Al _97.5 Cr _2.5 alloy was sputtered thereon to form a 90 nm thick reflective layer. After the disk was taken out of the vacuum container, an acrylic UV curable resin (SD-101 manufactured by Dainippon Ink Co., Ltd.) was spin-coated on the reflective layer and cured by UV irradiation to form a film having a thickness of 3 μm.
m resin layer, then apply a slow-acting UV curable resin using a screen printer, and irradiate with UV light,
Two optical disks produced in the same manner were adhered to obtain an optical recording medium of the present invention.

The recording characteristics of this disk were evaluated under condition 2. The overwrite recording was performed 10 times, and the jitter was measured.
It was a good value of 3%. While recording, in the air without humidity control such as humidification, 1
It was left for 00 hours. Thereafter, when the jitter of the same portion was measured, there was no change at 1.58 ns. Furthermore, when this portion was overwritten once, the jitter was 2.
It was confirmed that there was no practical problem with a good value of 11.8% of the window width at 01 ns. Example 26 A disk was manufactured in the same manner as in Example 25 except that the carbon layer between the recording layer and the second dielectric layer was replaced with GeN _1.2 having a thickness of 2 nm.

The recording characteristics of this disk were evaluated under condition 2. When overwrite recording was performed 10 times and the jitter was measured, it was 1.50 ns, and the window width was 8.
It was a good value of 8%. As recorded, in air without humidity control such as humidification, 80 ° C
Left for 0 hours. After that, when the jitter of the same portion was measured, there was no change of 1.50 ns. Furthermore, when this portion was overwritten once, the jitter was 2.0
At 0 ns, it was confirmed that there was no practical problem with a good value of 11.8% of the window width.

(Comparative Example 1) Thickness 0.6 mm, diameter 12c
Sputtering was performed while rotating a polycarbonate substrate with a spiral groove having a pitch of 1.48 μm (land width 0.74 μm, groove width 0.74 μm) at 30 revolutions per minute. First, the inside of the vacuum vessel was evacuated to 1 × 10 ⁻³ Pa, and then SiO 2 was introduced in an atmosphere of Ar gas of 0.2 Pa.
_A first dielectric layer having a thickness of 95 nm was formed on the substrate by sputtering ZnS to which 20 mol% of ₂ was added. Then G
An alloy target composed of e, Sb, and Te was sputtered to obtain a recording layer having a thickness of 20 nm and a composition of Ge _17.1 Sb _27.6 Te _55.3 . Further, as the second dielectric layer, the same ZnS.SiO ₂ as that of the first dielectric layer was sputtered to have a thickness of 16 nm, and an Al _97.5 Cr _2.5 alloy was sputtered thereon to form a reflective layer having a thickness of 150 nm. After the disk was taken out of the vacuum container, an acrylic UV-curable resin (SD-101, manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated on the reflective layer, and cured by UV irradiation to a film thickness of 3 μm
Was formed, and then a slow-acting UV-effect resin was applied using a screen printer, and after irradiating with UV rays, two discs produced in the same manner were laminated to obtain an optical recording medium.

The same measurement as in Example 1 was performed.
The jitter after overwriting 100,000 times is 4.77 ns, which is as large as 14% of the window width, and the signal amplitude is 10%.
The amplitude was 70% of the amplitude after overwriting twice, and the contrast was low. The error rate after one recording was 4.0 × 10 ⁻⁵ . As in Example 1, the sample was dried (in the air without humidity control such as humidification) and left at 80 ° C. for 100 hours. Thereafter, when the byte error rate of the same part was measured, it was 3.0.
There was almost no change at ^10-5 . However, when this portion was overwritten once, an error occurred and the byte error rate deteriorated so that the byte error rate could not be measured. The cause of the error is due to the deterioration of the jitter, and the jitter at this time is 6.1.
3 ns, which was about 18% of the window width.

Comparative Example 2 A disc was manufactured in the same manner as in Comparative Example 1, except that a carbon layer having a thickness of 2 nm was provided between the recording layer and the second dielectric layer. When the same measurement as in Example 1 was performed, the jitter after overwriting 100,000 times was 5.0.
9 ns, which was as large as 15%, the signal amplitude was 65% of the amplitude after 10 times of overwriting, and the contrast was low. The error rate after one recording was 1.8 × 10 ⁻⁵ . As in Example 1,
Drying (in air without humidity control such as humidification), 8
It was left for 100 hours at 0 ° C. After that, the byte error rate of the same part was measured to be 2.4 × 10 ^−5.
And there was almost no change. However, when this portion was overwritten once, an error occurred and the byte error rate deteriorated so that the byte error rate could not be measured. When the jitter at this time was measured, it was 6.46 ns, and the window width of 19
%.

Comparative Example 3 A disk was prepared in which the second dielectric layer of Comparative Example 1 was removed and a carbon layer having a thickness of 18 nm was provided between the recording layer and the reflective layer. The carbon layer is
The film was formed by sputtering a carbon target in an atmosphere of Ar gas of 0.2 Pa.

The same measurement as in Example 1 was performed.
The jitter after overwriting 10,000 times was 5.11 ns, which was as large as 15%, the amplitude of the signal was 60% of the amplitude after overwriting 10 times, and the contrast was low. The disc was heated at a temperature of 90 ° C. and a relative humidity of 80%.
Was left for 140 hours under the above conditions, a burst defect was observed, which was considered to be separation between the second dielectric layer and the recording layer.

(Comparative Example 4) A disc was prepared in which the second dielectric layer of Comparative Example 1 was removed, and a film mainly composed of carbon and oxygen was provided with a thickness of 18 nm between the recording layer and the reflective layer.
Note that the film containing carbon and oxygen as main components was formed by sputtering a carbon target under an atmosphere of a mixed gas of pressure of 0.2 Pa and argon: oxygen = 9: 1.

The same measurement as in Example 1 was performed.
The jitter after overwriting 100,000 times is 4.75 ns, which is as large as 14% of the window width, and the signal amplitude is 10%.
The amplitude was 65% of the amplitude after the overwriting twice, and the contrast was low. In addition, the temperature of this disk is 90 ° C,
When left for 140 hours under the condition of a relative humidity of 80%,
Burst defects which seemed to be peeling between the second dielectric layer and the recording layer were observed.

Comparative Example 5 The composition of the recording layer was Ge ₂ Sb ₂ T
e ₅ [i.e. _{(Ge 0.5 Te 0.5) 0.444 (} Sb 0. 4 Te
_0.6 ) _0.556 ], and a disk was obtained in the same manner as in Example 1.

When the jitter after 100,000 times of overwriting was measured, it was 4.08 ns.
%, Which was sufficiently small for practical use. The amplitude of the signal is 1
There was almost no change compared to the amplitude of the signal after 0 overwrites, and no burst defect was observed.

The recording was performed once on this disk, and the byte error rate at that time was measured.
^-5 . 90 ° C., relative humidity 8 as recorded
It was left for 140 hours under the condition of 0%. Thereafter, when the byte error rate of the same portion was measured, it was found to be 9.0 × 10 ^−3.
And greatly deteriorated. When the reproduced waveform was observed, it was presumed that the amplitude was reduced and a part of the amorphous part was crystallized.

The composition of the recording layer was Ge ₁ Sb ₂ Te.
₄ [ie (Ge _0.5 Te _0.5 ) _0.287 (Sb _0.4 T
e _0.6 ) _0.714 ], a byte error rate of _5.50 if left at 90 ° C. and a relative humidity of 80% for 140 hours.
It deteriorated greatly from 0 × 10 ⁻³ to 2.0 × 10 ⁻² , and the archival characteristics were insufficient.

Comparative Example 6 The composition of the recording layer was Ge _14.0 Sb
_36.0 Te _50.0 [that is, ｛(Ge _0.5 Te _0.5 )
Except that the _{0. 318 (Sb 0.4 Te 0.6)} 0.682} 0.880 Sb 0.120] , thereby obtaining the disks in the same manner as in Example 1. 10
When the jitter after the overwriting was measured twice, it was found that the minimum was 6.83 ns and only 20% of the window width was obtained. This was presumed to be due to poor erasing characteristics.

Comparative Example 7 The composition of the recording layer was Ge _42.0 Sb
_9.0 Te _49.0 [That is, ｛(Ge _0.5 Te _0.5 ) _{0.8 78} (S
b _0.4 Te _0.6 ) _0.122 ｝ _0.957 Sb _0.043 ], and a disk was obtained in the same manner as in Example 1. When the jitter after 10 times of overwriting was measured, the minimum was 6.8.
Only 1 ns and 20% of the window width were obtained. This was presumed to be due to poor erasing characteristics.

Comparative Example 8 The composition of the recording layer was Ge _6.0 Sb
_38.0 Te _56.0 [that is, ｛(Ge _0.5 Te _0.5 )
Except for using _{0.1 26 (Sb 0.4 Te 0.6)} 0.874} 0.953 Sb 0.047], to obtain a disk in the same manner as in Example 1. 10
When the jitter after the overwriting was measured twice, the minimum was 6.11 ns, which was only 18% of the window width. This was presumed to be due to the low contrast between the crystalline phase and the amorphous phase.

Comparative Example 9 The composition of the recording layer was changed to (Ge_TwoSb_Two
Te_Five)_0.70Nb_0.30[That is, ｛(Ge_0.5Te _0.5)
_0.444(Sb_0.4Te_0.6)_0.556｝_0.7Nb_0.3]
Except for the above, a disk was produced in the same manner as in Example 1. 10
The jitter after overwriting was measured
6.80 ns and only 20% of window width can be obtained
Was. This is presumed to be due to poor erasing characteristics.
You.

Comparative Example 10 The composition of the recording layer was Ge ₂ Sb ₂
Te ₅ [i.e. _{(Ge 0.5 Te 0.5) 0.444 (} Sb 0. 4 T
e _0.6 ) _0.556 ], except that 6
A layer disc was obtained.

Recording was performed once on this disk, and the byte error rate at that time was 2.5 × 10 ⁻⁵ . The recording was left for 140 hours at 90 ° C. and 80% relative humidity. Thereafter, when the byte error rate of the same portion was measured, an error occurred and the byte error rate could not be measured. When the reproduced waveform was observed, it was presumed that the amplitude was greatly reduced and a part of the amorphous portion was crystallized.

The composition of the recording layer was Ge ₁ Sb ₂ Te.
₄ [ie (Ge _0.5 Te _0.5 ) _0.287 (Sb _0.4 T
e _0.6 ) _0.714 ], a byte error rate of _5.50 if left at 90 ° C. and a relative humidity of 80% for 140 hours.
From 0 × 10 ⁻³ , the archival characteristics deteriorated greatly, indicating that measurement was impossible, and the archival characteristics were insufficient.

(Comparative Example 11) The composition of the recording layer was Ge _0.5 T
e _0.5 [i.e. _{{(Ge 0.5 Te 0.5) 1.00} (Sb 0. 4 T
e _0.6 ) _{0.00 1.00 1.00} Sb _0.00 ]
A 6-layer disc was prepared in the same manner as in 3. The disk was recorded once and the byte error rate at that time was not measured. This is because the jitter was bad, and the value of the jitter at this time was 20%.

(Comparative Example 12) The composition of the recording layer was Ge ₂ Sb ₂
Te ₅ [i.e. _{(Ge 0.5 Te 0.5) 0.444 (} Sb 0. 4 T
e _0.6 ) _0.556 ], and a six-layer disc was obtained in the same manner as in Example 17.

Recording was performed once on this disk, and the byte error rate at that time was 1.5 × 10 ⁻⁵ . The recording was left for 140 hours at 90 ° C. and 80% relative humidity. Thereafter, when the byte error rate of the same portion was measured, an error occurred and the byte error rate could not be measured. When the reproduced waveform was observed, it was presumed that the amplitude was greatly reduced and a part of the amorphous portion was crystallized.

Further, the composition of the recording layer was Ge ₁ Sb ₂ Te
₄ [ie (Ge _0.5 Te _0.5 ) _0.287 (Sb _0.4 T
e _0.6 ) _0.714 ], when left at 140 ° C. under the conditions of 90 ° C. and 80% relative humidity, the byte error rate is 1.
From 0 × 10 ^-4 , the measurement was greatly deteriorated, ^indicating that measurement was impossible. Archival properties were inadequate.

(Comparative Example 13) The composition of the recording layer was Ge _0.5 T
e _0.5 [i.e. _{{(Ge 0.5 Te 0.5) 1.00} (Sb 0. 4 T
e _0.6 ) _{0.00 1.00 1.00} Sb _0.00 ]
A six-layer disc was prepared in the same manner as in No. 7.

Recording was performed once on this disk, and the byte error rate at that time was measured. This is because the jitter was bad, and the value of the jitter at this time was 20%. (Comparative Example 14) The composition of the recording layer was changed to Ge _6.0 Sb _38.0 Te.
_56.0 [that is, ｛(Ge _0.5 Te _0.5 ) _{0.1 26} (Sb _0.4 T
e _0.6 ) _0.874 { _0.953 Sb _0.047 ], and a disk was obtained in the same manner as in Example 17. When jitter was measured after 10 times of overwriting, only a minimum of 6.00 ns and only 18% of the window width were obtained. This was presumed to be due to the low contrast between the crystalline phase and the amorphous phase.

(Comparative Example 15) A disk was produced in the same manner as in Example 1 except that the thickness of the recording layer was changed to 60 nm. When the repetitive overwrite characteristics of the disk were evaluated, the jitter was deteriorated until measurement was impossible after 100 repetitions. The reason is presumed that the recording layer is likely to move because the recording layer is thick.

When recording was performed once on the unrecorded portion of this disk and the subsequent byte error rate was measured,
It was 5.9 × 10 ^-4 . 90 as recorded
C. and 80% relative humidity for 140 hours. After that, when the byte error rate of the same part was measured,
An error occurred and the byte error rate could not be measured. When the reproduced waveform was observed, it was presumed that the amplitude was greatly reduced and a part of the amorphous portion was crystallized.

Further, even if the thickness of the recording layer is 45 nm,
Jitter could not be measured after 300 repetitive overwrites. In addition, recording was performed once, and 90 ° C. and a relative humidity of 80 ° C.
When left for 140 hours under the condition of%, the byte error rate greatly deteriorated from 4.0 × 10 ⁻⁴ to 2.5 × 10 ⁻³ . Observation of the playback waveform shows that the amplitude has decreased,
It was presumed that part of the amorphous part was crystallized.

(Comparative Example 16) A disk was produced in the same manner as in Example 1, except that the thickness of the recording layer was changed to 5 nm. 10
When the jitter after the overwriting was measured twice, a minimum of 5.81 ns and only 17% of the window width were obtained. This was presumed to be due to the low contrast between the crystalline phase and the amorphous phase.

(Comparative Example 17) A disk was produced in the same manner as in Example 6, except that the thickness of the recording layer was changed to 60 nm. When the repetitive overwrite characteristics of the disk were evaluated, the jitter was deteriorated until measurement was impossible after 100 repetitions. The reason is presumed that the recording layer is likely to move because the recording layer is thick.

When recording was performed once on the unrecorded portion of this disk and the byte error rate was measured thereafter,
It was 8.0 × 10 ^-4 . 90 as recorded
C. and 80% relative humidity for 140 hours. After that, when the byte error rate of the same part was measured,
An error occurred and the byte error rate could not be measured. When the reproduced waveform was observed, it was presumed that the amplitude was greatly reduced and a part of the amorphous portion was crystallized.

Further, even if the thickness of the recording layer is 45 nm,
Jitter could not be measured after 300 repetitive overwrites. In addition, recording was performed once, and 90 ° C. and a relative humidity of 80 ° C.
When left at 140% for 140 hours, the byte error rate was greatly degraded from 3.7 × 10 ^-4 to 3.1 × 10 ^-3 . Observation of the playback waveform shows that the amplitude has decreased,
It was presumed that part of the amorphous part was crystallized.

(Comparative Example 18) A disk was produced in the same manner as in Example 6, except that the thickness of the recording layer was changed to 5 nm. 10
When the jitter after overwriting was measured one time, it was found that the minimum was 5.42 ns and only 16% of the window width was obtained. This was presumed to be due to the low contrast between the crystalline phase and the amorphous phase.

(Comparative Example 19) A disk was manufactured in the same manner as in Example 17, except that the thickness of the recording layer was changed to 60 nm.
When the repetitive overwrite characteristics of the disk were evaluated, the jitter was deteriorated until measurement was impossible after 100 repetitions. The reason is presumed that the recording layer is likely to move because the recording layer is thick.

Recording was performed once on the unrecorded portion of the disk, and the subsequent byte error rate was measured.
It was 6.2 × 10 ^-4 . 90 as recorded
C. and 80% relative humidity for 140 hours. After that, when the byte error rate of the same part was measured,
An error occurred and the byte error rate could not be measured. When the reproduced waveform was observed, it was presumed that the amplitude was greatly reduced and a part of the amorphous portion was crystallized.

Further, even if the thickness of the recording layer is 45 nm,
Jitter could not be measured after 300 repetitive overwrites. In addition, recording was performed once, and 90 ° C. and a relative humidity of 80 ° C.
When left for 140 hours under the condition of%, the byte error rate was greatly deteriorated from 4.9 × 10 ⁻⁴ to 5.1 × 10 ⁻³ . Observation of the playback waveform shows that the amplitude has decreased,
It was presumed that part of the amorphous part was crystallized.

(Comparative Example 20) A disk was produced in the same manner as in Example 17, except that the thickness of the recording layer was changed to 5 nm. 1
When jitter was measured after overwriting 0 times, a minimum value of 6.38 ns was obtained, which was only 19% of the window width. This was presumed to be due to the low contrast between the crystalline phase and the amorphous phase.

[0137]

According to the optical recording medium of the present invention, the following effects can be obtained. (1) Good overwrite characteristics can be obtained even if left for a long time after recording. (2) Even if left for a long time after recording, there is no occurrence of burst defects and no disappearance of recording marks. (3) It can be easily manufactured by a sputtering method.

[Brief description of the drawings]

FIG. 5 is a chart of a depth profile of an A sample.

FIG. 5 is a chart of a depth profile of a B sample.

FIG. 5 is a chart of a KLL Auger electron spectrum of carbon of Sample A.

FIG. 5 is a chart of a KLL Auger electron spectrum of carbon of a B sample.

FIG. A sample carbon depth
It is the chart which decomposed the profile.

FIG. Depth of carbon of B sample
It is the chart which decomposed the profile.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI G11B 7/24 535 G11B 7/24 535H (JP, A) JP-A-6-191161 (JP, A) JP-A-2-139283 (JP, A) JP-A-63-251290 (JP, A) WO 99/06220 (WO, A1) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B41M 5/26 G11B 7/24 511

Claims (6)

(57) [Claims] (1) irradiating light to record information;
Erasing and playback are possible, and recording and erasing of information
It is performed by a reversible phase change between an amorphous phase and a crystalline phase. In an optical recording medium having at least a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer on a substrate in this order, recording is performed. A layer containing carbon as a main component is provided between the layer and the first dielectric layer so as to be in contact with the recording layer, and the recording layer is made of the following formula (I) Ｇ (Ge _0.5 Te _0.5 ) _x (Sb _0.4 Te _{0.6 ) 1-x} 1-yz} Sb y a z (I) ( wherein, a represents belongs, Ge, Sb, the group 6B of the second period in the periodic table of the elements from group 3A of the sixth period, except for Te elemental And x, y, and z each represent a number and satisfy the following relational expression: 0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.08, z = 0 or 0.2 ≦ x ≦ 0.8, 0 ≦ y ≦ 0.08, 0
<Z ≦ 0.2), and the thickness of the recording layer is 7 nm or more and 35 nm or less. 2. Recording of information by irradiating light,
Erasing and playback are possible, and recording and erasing of information
It is performed by a reversible phase change between an amorphous phase and a crystalline phase. In an optical recording medium having at least a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer on a substrate in this order, recording is performed. A layer mainly composed of carbon is provided between the recording layer and the first dielectric layer so as to be in contact with the recording layer, and a layer mainly composed of carbon, and carbon and oxygen are provided between the recording layer and the second dielectric layer. A layer mainly composed of, a layer mainly composed of carbon and nitrogen, and a layer mainly composed of carbon, oxygen and nitrogen. Further, the recording layer has the following formula (II) ＩＩ (Ge _{0.5 Te 0.5) x (Sb 0.4} Te 0.6) 1-x} 1-yz Sb y a z (II) ( wherein, a represents, Ge, Sb, from the second period in the periodic table of elements except Te sixth It represents an element belonging to group 3A to group 6B of the period, x, y, and z represent numbers and satisfy the following relational expression: 0.2 ≦ x ≦ 0.95, 0.01 ≦ y ≦ 0.08, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2) and the thickness of the recording layer is 7 nm.
An optical recording medium having a thickness of 35 nm or less. 3. Recording of information by irradiating light,
Erasing and playback are possible, and recording and erasing of information
It is performed by a reversible phase change between an amorphous phase and a crystalline phase. In an optical recording medium having at least a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer on a substrate in this order, recording is performed. Providing a layer mainly composed of carbon between the layer and the first dielectric layer so as to be in contact with the recording layer, and providing a layer mainly composed of germanium nitride between the recording layer and the second dielectric layer; Furthermore, the recording layer is represented by the following formula _{(III) {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y A z (III) ( wherein, A represents, Ge, Sb, In the periodic table of elements except for Te, elements belonging to Groups 3A to 6B in the second to sixth periods are shown, x, y, and z are numbers and satisfy the following relational expression: 0.2 ≦ x ≦ 0.95, 0.01 ≦ y ≦ 0.08, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.08,
0 <z ≦ 0.2) and the thickness of the recording layer is 7 nm.
An optical recording medium having a thickness of 35 nm or less. 4. The method according to claim 1, wherein the first and second dielectric layers are reduced.
Both ZnS and SiO _Two2. The method according to claim 1, further comprising:
4. The optical recording medium according to any one of claims 1 to 3. 5. The method according to claim 1, wherein the second dielectric layer comprises at least ZnS and SiO.
5. The optical recording medium according to claim 4, comprising ₂ and carbon. 6. The method according to claim 1, wherein the thickness of the layer mainly composed of carbon between the recording layer and the first protective layer is 0.5 nm or more and 4 nm or less. Optical recording medium.