JP2003233931A - Information recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent information recording medium capable of simultaneously realizing reliability and repeat rewriting performance in high- density recording without providing any interface layers. <P>SOLUTION: At least a recording layer 4 and an opposite layer 8 are disposed on a substrate 1, and a phase changes occurs between a crystal phase and an amorphous layer on the recording layer 4 by an optical means or an electric means. On the substrate 1, dielectric layers 2, 6 made of materials represented by (ZrO<SB>2</SB>)X(Zn-S)<SB>100-</SB>X (mol%), X being in a range of 50≤X≤80, are disposed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium for optically or electrically recording, erasing, rewriting, and reproducing information, and a manufacturing method thereof.

[0002]

The inventor has developed a large capacity rewritable phase change information recording medium, 4.7 GB / DVD-RAM, which can be used as a data file and an image file. This has already been commercialized.

This 4.7 GB / DVD-RAM is disclosed in, for example, Japanese Patent Publication No. 2001-322357 (Patent Document 1). The structure of the DVD-RAM disclosed in this publication is shown in FIG. The information recording medium 31 shown in FIG. 9 has a first dielectric layer 102, a first interface layer 103, a recording layer 4, a second interface layer 105, and a second dielectric layer on one surface of a substrate 1. It has a seven-layer structure in which 106, the light absorption correction layer 7, and the reflection layer 8 are formed in this order. In this information recording medium, the first dielectric layer is located closer to the incident laser light than the second dielectric layer. The first interface layer and the second interface layer have the same relationship. As described above, in the present specification, when the information recording medium includes two or more layers having the same function, the information recording medium is "first" and "second" in order from the side closer to the incident laser beam. It is called "third" ....

First dielectric layer 102 and second dielectric layer 1
06 has the functions of adjusting the optical distance to enhance the light absorption efficiency of the recording layer 4, and increasing the difference between the reflectance of the crystalline phase and the reflectance of the amorphous phase to increase the signal amplitude. ZnS-20 mol% Si, which is conventionally used as a material for the dielectric layer
O ₂ is an amorphous material, has a low thermal conductivity, is transparent, and has a high refractive index. In addition, ZnS-20 mol% Si
O ₂ has a high film formation rate during film formation, and has good mechanical properties and moisture resistance. Thus, ZnS-20 mol
% SiO ₂ is a good material for forming the dielectric layer.

When the thermal conductivity of the first dielectric layer 102 and the second dielectric layer 106 is low, when the laser beam is incident on the recording layer 4, heat is transferred from the recording layer 4 to the reflective layer 8. The heat can be quickly diffused in the thickness direction, and heat is less likely to diffuse in the in-plane direction of the dielectric layer 102 or 106.
That is, the recording layer 4 is cooled (that is, rapidly cooled) in a shorter time by the dielectric layer, and an amorphous mark (recording mark) is easily formed. If the recording mark is difficult to form, it is necessary to record with high peak power, and if the recording mark is easy to form, it is possible to record with low peak power. When the thermal conductivity of the dielectric layer is low, recording can be performed with a low peak power, so the recording sensitivity of the information recording medium is high. On the other hand, when the thermal conductivity of the dielectric layer is high, recording is performed with a high peak power, so the recording sensitivity of the information recording medium becomes low. The dielectric layer in the information recording medium exists in the form of a thin film so that the thermal conductivity cannot be measured accurately. Therefore, the inventors have adopted the recording sensitivity of the information recording medium as a relative criterion for knowing the magnitude of the thermal conductivity of the dielectric layer.

The recording layer 4 is formed by using a material containing Ge-Sn-Sb-Te that crystallizes at a high speed. An information recording medium having such a material as the recording layer 4 has not only excellent initial recording performance, but also excellent recording storability and rewritable storability. The phase change information recording medium records, erases and rewrites information by utilizing the reversible phase transformation of the recording layer 4 between the crystalline phase and the amorphous phase. When the recording layer 4 is irradiated with high-power laser light (peak power) and rapidly cooled, the irradiated portion becomes an amorphous phase and recording marks are formed. When the recording layer is heated and gradually cooled by irradiating low power laser light (bias power), the irradiated portion becomes a crystalline phase and the recorded information is erased. By irradiating the recording layer with laser light whose power is modulated between the peak power level and the bias power level, it is possible to rewrite new information while erasing already recorded information. The repetitive rewriting performance is represented by the number of times rewriting can be repeated within a range in which the jitter value has no practical problem. It can be said that the larger the number of times, the better the rewriting performance is. In particular, an information recording medium for data files is desired to have excellent rewritability.

First interface layer 103 and second interface layer 1
05 has a function of preventing mass transfer that occurs between the first dielectric layer 102 and the recording layer 4 and between the second dielectric layer 106 and the recording layer 4. Here, “mass transfer” means that the first and second dielectric layers ZnS-20 mol% Si are irradiated while the recording layer is repeatedly irradiated with laser light for rewriting.
This is a phenomenon in which S of O ₂ diffuses into the recording layer. A lot of S
If diffused into the recording layer, the reflectance of the recording layer is lowered, and the rewriting performance is deteriorated. This phenomenon is already known (Non-Patent Document 1, N. Yamada et al. Japan.
ese Journal of Applied Physics Vol.37 (1998) pp. 2
See 104-2110). Also, Japanese Patent Laid-Open Publication No. 10-2
No. 75360 (Patent Document 2) and International Publication No. WO97.
/ 34298 pamphlet (Patent Document 3) discloses that an interface layer for preventing this phenomenon is formed using a nitride containing Ge.

The light absorption correction layer 107 adjusts the ratio Ac / Aa of the light absorption rate Ac when the recording layer 4 is in the crystalline state and the light absorption rate Aa when the recording layer 4 is in the amorphous state, and the mark shape at the time of rewriting. Has a function to prevent distortion. Reflective layer 8
Has a function of optically increasing the amount of light absorbed in the recording layer 4, and thermally thermally diffuses the heat generated in the recording layer 4 and rapidly cools it to amorphize the recording layer 4. It has the function of facilitating. The reflective layer 8 also has a function of protecting the multilayer film from the use environment.

As described above, the information recording medium shown in FIG.
By having a structure in which seven layers each functioning as described above are laminated, excellent repetitive rewriting performance and high reliability are secured in a large capacity of 4.7 GB, and the product has been commercialized.

Various materials have been previously proposed as materials suitable for the dielectric layer of the information recording medium. For example, in Japanese Patent Laid-Open Publication No. 5-159373 (Patent Document 4), in an optical information recording medium, at least a nitride, a carbide, an oxide, or a sulfide whose heat-resistant protective layer has a higher melting point than Si. It is disclosed that it is formed by a mixture of one or more compounds and a low alkali glass. In the publication, Nb, Z
Carbides, oxides and sulfides of r, Mo, Ta, Ti, Cr, Si, Zn and Al are exemplified. Further, in the publication, low-alkali glass is composed of SiO ₂ , BaO, B ₂ O ₃ , and A.
It is disclosed that the main component is l ₂ O ₃ .

[0011]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-322357

[Patent Document 2] Japanese Patent Application Laid-Open No. 10-275360 (claims)

[Patent Document 3] WO97 / 34298 (Claims)

[Patent Document 4] Japanese Unexamined Patent Publication No. 5-159373 (Claims)

[Patent Document 5] Japanese Patent Laid-Open No. 2002-260281 (Claims)

[Non-Patent Document 1] N. Yamada et al. Japanese Journal
of Applied Physics Vol.37 (1998) pp. 2104-2110

[0012]

As described above, when the first and second dielectric layers are formed of ZnS-20 mol% SiO ₂ , the dielectric layer and the recording layer are prevented to prevent S diffusion. An interfacial layer is inevitably required between and. However, considering the price of the medium, it is desirable that the number of layers constituting the medium is as small as one. With a small number of layers,
The material cost can be reduced, the manufacturing apparatus can be downsized, and the production amount can be increased by shortening the manufacturing time, which leads to the cost reduction of the medium.

The inventor has examined the possibility of eliminating at least one of the first interface layer and the second interface layer as one method of reducing the number of layers. In that case, the inventor considered that it is necessary to form the dielectric layer with a material other than ZnS-20 mol% SiO ₂ so that the diffusion of S from the dielectric layer to the recording layer due to repeated recording does not occur. Further, regarding the material of the dielectric layer, the adhesion with the recording layer which is a chalcogenide material is good, and the above 7
It is desired that a high recording sensitivity equal to or higher than that of a layer structure be obtained, that it be transparent, and that it have a high melting point so as not to melt during recording.

According to the present invention, even when the recording layer is formed so as to be in direct contact with the recording layer, the substance does not move from the dielectric layer to the recording layer and the adhesion to the recording layer is good, even if the interface layer is not provided. The main object is to provide an information recording medium provided with a certain dielectric layer and having excellent rewritability.

It should be noted that the above-mentioned Patent Document 4 does not mention the problem of substance transfer from the dielectric layer to the recording layer.
Therefore, it should be noted that this publication does not teach the problem to be solved by the present invention and the means for solving the problem, that is, the specific composition.

[0016]

The inventors of the present invention, as will be described in the examples below, use various compounds to form a dielectric layer, and the adhesion of the dielectric layer to a recording layer, And the repetitive rewriting performance of the information recording medium was evaluated. As a result, when the dielectric layers are provided directly above and below the recording layer without interposing the interfacial layer, when the dielectric layer which is easily diffused in the recording layer, for example, the conventional dielectric layer is formed of ZnS-20 mol% SiO ₂ , It was found that the adhesion to the recording layer was good, but the repetitive rewriting performance of the medium was poor. Also, for example, Zr
O ₂ has a low thermal conductivity and a high melting point. Therefore, if it is used as a dielectric layer, the recording sensitivity of the information recording medium can be increased and excellent repetitive rewriting performance can be secured. However, when the dielectric layer was formed using ZrO ₂ , the result was that the adhesion to the recording layer was poor. For information recording media formed by contacting the dielectric layer with the recording layer using various other oxides, nitrides, sulfides, and selenides, the adhesion of the dielectric layer to the recording layer and the rewritability Was evaluated. However, when the dielectric layer was formed using one kind of oxide, nitride, sulfide, or selenide, it was not possible to achieve both good adhesion and good rewritability.

Therefore, the inventor of the present invention studied the formation of the dielectric layer by using a mixture of ZnS-20 mol% SiO ₂ which has been conventionally used, except that the compound to be mixed with ZnS is other than SiO _2. did. As a result, Zn
The inventors have found that the combination of S and ZrO ₂ is suitable as a constituent material of the dielectric layer in contact with the recording layer, and have completed the present invention.

That is, the present invention is an information recording medium including a substrate and a recording layer, wherein the recording layer undergoes a phase transformation between a crystalline phase and an amorphous phase upon irradiation of light or application of electric energy. There is provided an information recording medium further including a Zr—Zn—S—O-based material layer containing Zr, Zn, S and O. Here, simply, Zr, Zn, S and O
The material layer containing is a substance that does not matter what compound each atom exists as. However, in this material, Zr and O exist in the form of ZrO ₂ , and Zn and S exist in the form of ZnS, Zn not bound to other atoms, and S not bound to other atoms. it seems to do. As described below, Z
In the present specification, nS, Zn that is not bonded to another atom, and S that is not bonded to another atom are “Zn—
It is treated as a constituent of the system labeled "S". Z
The layer made of a material containing r, Zn, S, and O has properties that it adheres well to the recording layer and that mass transfer does not easily occur between the layer and the recording layer.

The information recording medium of the present invention is a medium for recording and reproducing information by irradiating light or applying electric energy. In general, light irradiation is performed by irradiating a laser beam (that is, a laser beam), and application of electric energy is performed by applying a voltage to the recording layer. Hereinafter, the Zr-Zn-S-O-based material layer forming the information recording medium of the present invention will be described more specifically.

More specifically, the information recording medium of the present invention has the formula (1):

Embedded image Zr _B Zn _C S _D O _100-BCD (atomic%) ... (1) (wherein B, C and D are respectively 8 ≦ B ≦ 33, 3
≦ C ≦ 30, C ≦ D ≦ 2C <45, and 40 ≦ B + C + D ≦ 80)). It is included as an element. Here, “atomic%” indicates that the formula (1) is a composition formula expressed with the total number of Zr, Zn, S and O atoms as a reference (100%). In the following formulas, the expression "atomic%" is used for the same purpose.

In the formula (1), it does not matter what compound each atom of Zr, Zn, S and O exists as. It is difficult to determine the composition of the compound when investigating the composition of the layer formed in the thin film because the material is specified by such a formula, and in reality, only the elemental composition (that is, the ratio of each atom) is determined. This is because there are many cases in which it is requested. As described above, in the material represented by the formula (1),
It is considered that most of Zr exists together with O as ZrO ₂ and most of Zn exists together with S as Zn—S. Here, "Zn-S" means Zr-Zn-S-O.
In the system material layer, Zn and S do not exist only in the form of zinc sulfide ZnS, and Zn and / or S that are not bonded to other atoms
It also indicates that there may be S that is not bonded to another atom. Therefore, Zn-S is, for example, ZnS.
Sometimes expressed as _1.5 . Such a display indicates that (number of S atoms) / (number of Zn atoms) is 1.5. In this case, the Zr—Zn—S—O-based material layer contains excess S that does not bond with Zn (or another atom). In the formula (1), C ≦ D ≦ 2C
Therefore, in the material represented by the formula (1), (the number of S atoms) / (the number of Zn atoms) is 1 or more and 2 or less.

In the information recording medium, the Zr-Zn-S-O-based material layer substantially made of the material represented by the above formula (1) is one of the two dielectric layers adjacent to the recording layer. It is preferable to exist as one of the dielectric layers, and it is more preferable to exist as both of the dielectric layers. In the dielectric layer containing Zr, Zn, S and O in the above range, ZrO ₂ having a melting point of 2700 ° C. or higher ensures transparency and excellent rewritability,
-S secures adhesion to the recording layer which is a chalcogenide material. Further, the ZrO ₂ thin film is amorphous and the ZnS thin film is crystalline. When two materials having different structures are mixed to complicate the structure, the heat conductivity can be reduced. As a result, the action of rapidly cooling the recording layer is increased, so that the recording sensitivity of the information recording medium can be increased. Therefore, this information recording medium does not cause peeling between the recording layer and the dielectric layer even without the interface layer, and exhibits excellent rewritability and recording sensitivity. In the information recording medium, the layer of the material represented by the formula (1) is
The interface layer may be located between the recording layer and the dielectric layer.

The Zr-Zn-S-O-based material layer substantially composed of the material represented by the formula (1) has the formula (11):

Embedded image From the material represented by (ZrO ₂ ) _X (Zn—S) _100-X (mol%) ... (11) (wherein X is 50 ≦ X ≦ 80), It may be a composed layer. Formula (11) is Zr-
When the Zn—S—O-based material layer is composed of ZrO ₂ and Zn—S, the preferable ratio of the two components is shown. Here, “mol%” means that each compound (Zn
-S is also regarded as one compound) based on the total number (100
%) Is indicated as the composition formula.
In the following formula, the expression "mol%" is used for the same purpose.

The layer substantially consisting of the material represented by the formula (11) is also preferably present as one of the two dielectric layers adjacent to the recording layer, and both dielectric layers are present. More preferably, it is present as a body layer. The effect of using the layer substantially consisting of the material represented by the formula (11) as the dielectric layer is as described in relation to the material represented by the formula (1). Here, the content of ZrO ₂ is preferably 50 mol% or more in order to ensure good repetitive rewriting performance of the information recording medium.
On the other hand, in order to secure the adhesion by Zn-S, ZrO
The content of ₂ is preferably 80 mol% or less. The layer substantially made of the material represented by the formula (11) may be an interface layer located between the recording layer and the dielectric layer in the information recording medium.

In the information recording medium of the present invention, Zr-Z
The n-S-O-based material further contains Si and has the formula (2):

Embedded image _{Zr E Si F Zn G S H} O 100-EFGH ( atomic%) ... (2) (respectively wherein, E, F, G and H are, 1 ≦ E ≦ 3
0, 0 <F ≦ 23, 2 ≦ G ≦ 30, G ≦ H ≦ 2G <45
, And 40 ≦ E + F + G + H ≦ 80).

Also in the formula (2), Zr, Si, Zn,
It does not matter what compound each atom of S and O exists as, and the material is specified by such a formula for the same reason as in the formula (1). In the material represented by the formula (2), most of Si is considered to exist as SiO ₂ together with O. Also, G ≦ H ≦ 2G
Is (atomic number of S) in the material represented by the formula (2).
It is shown that / (number of Zn atoms) is 1 or more and 2 or less.

The layer substantially consisting of the material represented by the formula (2) is also preferably present as either one of the two dielectric layers adjacent to the recording layer, and both dielectric layers are present. More preferably, it is present as a body layer. In an information recording medium having a Zr-Zn-S-O-based material layer containing Si as a dielectric layer, good adhesion between the dielectric layer and the recording layer is ensured, and excellent repetitive rewriting performance is secured. In addition to that, higher recording sensitivity is realized. It is considered that this is because the thermal conductivity of the layer is lowered by containing Si. The layer substantially made of the material represented by the formula (2) may be an interface layer located between the recording layer and the dielectric layer in the information recording medium.

The Zr-Zn-S-O-based material layer containing Si has the formula (21):

Embedded image (ZrO ₂ ) _Y (SiO ₂ ) _Z (Zn-S) _100-Y-Z (mol%) ... (21) (wherein Y and Z are respectively 20 ≦ Y ≦ 70, 10
Within the range of ≦ Z ≦ 50, and 50 ≦ Y + Z ≦ 80), the layer may consist essentially of the material. Equation (21), Zr-Zn-S-O-based material layer containing Si _is if composed of a mixture of ZrO 2, SiO _2, and Zn-S, shows a preferred ratio of the three components. A layer consisting essentially of the material represented by formula (21)
Among the dielectric layers adjacent to the recording layer, it is preferable to exist as one of the dielectric layers, and it is more preferable to exist as both of the dielectric layers. Alternatively, the formula (2
In the information recording medium, the layer substantially composed of the material represented by 1) may be an interface layer located between the recording layer and the dielectric layer.

Substantially made of the material represented by the formula (21).
When the layer is a dielectric layer, SiO ₂Is an information recording medium
It has the function of increasing the recording sensitivity of. Recording of information recording medium
In order to increase the sensitivity, in formula (21), SiO
₂Content (ie, Z) of 10 mol% or more
preferable. On the other hand, SiO₂Too much content of other
The proportion of components is reduced, and the adhesion and information to the recording layer
Repeated rewriting performance of the recording medium is deteriorated. According to
And SiO₂The content of is preferably 50 mol% or less.
Good Furthermore, SiO₂Adjust in the range of 10 to 50 mol%
It is possible to adjust the recording sensitivity by adjusting
Become. In the material represented by the formula (21), (Zn-
The content of S) is set in order to secure adhesion with the recording layer.
20 mol% or more is preferable, and S to the recording layer is
In order to prevent the diffusion of
Preferably there is. Therefore, in equation (21)
Is preferably 50 ≦ Y + Z ≦ 80.

The material represented by the formula (21) may contain ZrO ₂ and SiO ₂ in substantially equal proportions. In that case, this material has the following formula (22):

Embedded image (ZrSiO ₄ ) _A (Zn—S) _100-A (mol%) ... (22) (wherein A is in the range of 33 ≦ A ≦ 67). ZrSiO ₄ is a composite oxide containing ZrO ₂ and SiO ₂ in substantially equal proportions. ZrSiO ₄ has a high melting point and a stoichiometric composition, and thus has a stable structure.
The layer substantially consisting of the material represented by the formula (22) is also preferably present as either one of the dielectric layers adjacent to the recording layer, and is present as both dielectric layers. Is more preferable. In Expression (22), 3
By setting 3 ≦ A ≦ 67, ZrSiO ₄ and Z
n-S is present in the layer in the proper proportions. Therefore, the dielectric layer consisting essentially of the material represented by formula (22) is
It ensures good adhesion to the recording layer and ensures that the information recording medium has good recording sensitivity and repetitive rewriting performance. Zr that is a composite oxide of ZrO ₂ and SiO ₂
When SiO ₄ is formed, the ZrSiO ₄ thin film is amorphous. As described above, the ZnS thin film is crystalline.
Therefore, when two materials having different structures are mixed to complicate the structure, heat conduction can be reduced. As a result, the action of rapidly cooling the recording layer is increased, so that the recording sensitivity of the information recording medium can be increased. Therefore, the dielectric layer substantially composed of the material represented by the formula (22) has excellent adhesion to the recording layer, the information recording medium has better recording sensitivity, and good repetitive rewriting performance. Ensure to have. Alternatively, the layer substantially consisting of the material represented by the formula (22) may be an interface layer located between the recording layer and the dielectric layer in the information recording medium.

Zr- which constitutes the information recording medium of the present invention
In the Zn—S—O-based material layer, Zn atoms and S atoms are
It is preferable to satisfy the relation of 1 ≦ (number of S atoms) / (number of Zn atoms) ≦ 2. An information recording medium is formed by forming a Zr—Zn—S—O-based material layer having a (S atom number) / (Zn atom number) within this range so as to be in contact with the recording layer. Which has excellent adhesion between the Zr—Zn—S—O-based material layer and the recording layer, and has good rewritability and good recording sensitivity. (S atom number) / (Zn atom number) is larger than 1,
More preferable. In that case, the adhesion between the Zr—Zn—S—O-based material layer and the recording layer is further improved. However, (the number of S atoms) / (the number of Zn atoms) is preferably 2 or less. If the (number of S atoms) / (number of Zn atoms) exceeds 2, the proportion of S contained in the Zr—Zn—S—O-based material layer increases, and the dielectric layer is in contact with this layer. In that case, the rewriting performance deteriorates due to the diffusion of S into the recording layer.

The above formulas (1), (11), (2), (2)
The expressions represented by 1) and (22) are both 1 ≦ (S
The number of atoms of) / (the number of atoms of Zn) ≦ 2. Therefore, the content of S in the materials represented by these formulas is 33 atomic% or less, and the conventional (ZnS) ₈₀ (Si
O ₂ ) ₂₀ (mol%) (Zn _36.4 S _36.4 Si _9.0 O
_18.2 (atomic%)) is less than the S content (36.4 atomic%). That is, the materials represented by the above formulas are
By defining the ratio of the number of S atoms to the number of Zn atoms, an information recording medium can be obtained while maintaining good adhesion between a layer (specifically a dielectric layer) formed of the material and the recording layer. It is ensured that the crystallization performance and repetitive rewriting performance of the recording layer are not deteriorated.

The information recording medium of the present invention is preferably one in which the phase transformation reversibly occurs in its recording layer. That is, the information recording medium of the present invention is preferably provided as a rewritable information recording medium.

The recording layer in which the phase transformation reversibly occurs is specifically Ge-Sb-Te, Ge-Sn-Sb-Te, G
e-Bi-Te, Ge-Sn-Bi-Te, Ge-Sb
-Bi-Te, Ge-Sn-Sb-Bi-Te, Ag-
It is preferable to include any one material selected from In-Sb-Te and Sb-Te. All of these are high speed crystallization materials. Therefore, when the recording layer is formed of these materials, it is possible to obtain an information recording medium capable of recording at a high density and a high transfer rate and having excellent reliability (specifically, recording storability or rewriting storability). .

The information recording medium of the present invention may have two or more recording layers. Such an information recording medium has, for example, a single-sided two-layer structure in which two recording layers are laminated on one surface side of a substrate with a dielectric layer, an intermediate layer and the like interposed therebetween. The information recording medium having a single-sided, double-layer structure records information in two recording layers by irradiating light from one side. According to this structure, the recording capacity can be increased. Alternatively, the information recording medium of the present invention may have a recording layer formed on both surfaces of the substrate.

In the information recording medium of the present invention, the thickness of the recording layer is preferably 15 nm or less. When it exceeds 15 nm, the heat applied to the recording layer diffuses in the plane, and it becomes difficult to diffuse in the thickness direction.

The information recording medium of the present invention has a structure in which a first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer are formed in this order on one surface of a substrate. You may The information recording medium having this structure is a medium which is recorded by irradiation of light. In the present specification, “first
The "dielectric layer of" is a dielectric layer located closer to the incident light, and the "second dielectric layer" is a dielectric layer located farther from the incident light. The body layer.
That is, the irradiated light reaches the second dielectric layer from the first dielectric layer via the recording layer. The information recording medium having this configuration is used, for example, when recording / reproducing with a laser beam having a wavelength near 660 nm.

When the information recording medium of the present invention has this structure, at least one of the first dielectric layer and the second dielectric layer is a Zr-Zn-S-O-based material layer. (Specifically, the above formulas (1), (11), (2),
A layer consisting essentially of any one of the materials represented by (21) and (22). Preferably, both dielectric layers are the Zr-Zn-S-O-based material layers. In that case, both dielectric layers may be layers of the same composition or layers of different composition.

The information recording medium of the present invention has a structure in which a reflective layer, a second dielectric layer, a recording layer, and a first dielectric layer are formed in this order on one surface of a substrate. You may This configuration is adopted when it is necessary to reduce the thickness of the substrate on which light is incident. Specifically, the wavelength 40
When recording / reproducing with laser light of short wavelength around 5 nm,
The information recording medium having this configuration is used when the numerical aperture NA of the objective lens is increased to, for example, 0.85 to make the focal position shallow. In order to use such a wavelength and numerical aperture NA, the thickness of the substrate on which light is incident is set to, for example, 60 to
It should be about 120 μm. It is difficult to form a layer on the surface of such a thin substrate. Therefore, the information recording medium having this configuration is specified as a medium formed by sequentially forming a reflective layer or the like on one surface of the substrate on which the light is not incident as the support.

When the information recording medium of the present invention has this structure, at least one of the first dielectric layer and the second dielectric layer is a Zr-Zn-S-O-based material layer. Is. Preferably, both dielectric layers are Zr
-Zn-S-O-based material layer. In that case, both dielectric layers may be layers of the same composition or layers of different composition.

The present invention also provides a method for producing the information recording medium of the present invention, which includes a step of forming the above-mentioned Zr—Zn—S—O based material layer by a sputtering method. According to the sputtering method, Zr-Zn- having a composition substantially the same as the composition of the sputtering target.
An S-O material layer can be formed. Therefore, according to this manufacturing method, the Zr—Zn—S—O-based material layer having a desired composition can be easily formed by appropriately selecting the sputtering target.

Specifically, as a sputtering target, the following formula (10):

_{Embedded image} Zr _b Zn _c S _d O _100-bcd (atomic%) ... (10) (wherein b, c and d are respectively 11 ≦ b ≦ 30,
5 ≦ c ≦ 27, c ≦ d ≦ 2c <40, and 40 ≦ b + c + d ≦ 80) can be used. The formula (10) corresponds to a formula in which the material represented by the formula (110) described later is represented by the elemental composition. Therefore, according to this target, it is possible to form a layer substantially made of the material represented by the above formula (10).

The elemental composition of the layer formed by sputtering may differ from the elemental composition of the sputtering target depending on the sputtering apparatus, sputtering conditions, dimensions of the sputtering target, and the like.
Even if such a difference occurs when a sputtering target made of the material represented by the above formula (10) is used, the elemental composition of the formed layer is at least represented by the above formula (1). Become.

In the method of manufacturing the information recording medium of the present invention, the sputtering target is represented by the formula (110):

Embedded image From a material represented by (ZrO ₂ ) _x (Zn-S) _100-x (mol%) ... (110) (where x is 50 ≦ x ≦ 80), May be used. This corresponds to the formula in which the composition of the sputtering target is represented by the ratio of ZrO ₂ and Zn—S. As described above, the sputtering target is usually specified by a sputtering target made of a material containing Zr, Zn, S and O.
This is because the composition of these two components is displayed and sold. In addition, the inventor has found that the elemental composition obtained by analyzing with an X-ray microanalyzer of a commercially available sputtering target is approximately equal to the elemental composition calculated from the displayed composition (that is, the compositional expression (nominal composition ) Is appropriate). Therefore, according to this sputtering target, a layer substantially made of the material represented by the formula (11) is formed.

In the method of manufacturing the information recording medium of the present invention, in order to form the Zr-Zn-S-O-based material layer containing Si, the sputtering target of formula (2) is used.
0):

Embedded image _{Zr e Si f Zn g S h} O 100-efgh ( atomic%) ... (20) (wherein, e, f, g and h each, 3 ≦ e ≦ 2
7, 1 <f ≦ 20, 5 ≦ g ≦ 27, g ≦ h ≦ 2g <40
And is substantially composed of a material represented by the formula 40 ≦ e + f + g + h ≦ 80. When this sputtering target is used, a layer consisting essentially of the material represented by formula (21) or formula (2) is formed.

In the method of manufacturing the information recording medium of the present invention, the sputtering target is represented by the formula (210):

Embedded image (ZrO ₂ ) _y (SiO ₂ ) _z (Zn-S) _100-yz (mol%) ... (210) (wherein y and z are 20 ≦ y ≦ 70 and 10 respectively) ≦ z ≦ 50, and 50 ≦ y + z ≦
Of 80) may be used. The sputtering target is specified in this way because the sputtering target made of a material containing Zr, Zn, Si, S and O is usually Zr.
This is because the compositions of O ₂ , SiO ₂ , and Zn—S are displayed and sold. The inventors have confirmed that the composition display (that is, the nominal composition) is appropriate even for the target whose composition is displayed as in Expression (210). Therefore, according to this sputtering target, a layer substantially composed of the material represented by the formula (21) is formed.

The sputtering target represented by the above formula (210) may contain ZrO ₂ and SiO ₂ in substantially equal proportions. In that case, the sputtering target has the formula (220):

Embedded image A material represented by (ZrSiO ₄ ) _a (Zn—S) _100-a (mol%) ... (220) (where a is in the range of 33 ≦ a ≦ 67) Consists essentially of. According to this sputtering target, a layer substantially composed of the material represented by the formula (22) is formed.

The above equations (10), (110), (20),
Both (210) and (220) satisfy the relationship of 1 ≦ (number of S atoms) / (number of Zn atoms) ≦ 2. Therefore, if a sputtering target consisting essentially of the materials represented by these formulas is used, the relationship of 1 ≦ (number of S atoms) / (number of Zn atoms) ≦ 2 is satisfied.
A —S—O based material layer is formed.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are exemplifications, and the present invention is not limited to the following embodiments.

(Embodiment 1) As Embodiment 1 of the present invention, an example of an optical information recording medium for recording and reproducing information using a laser beam will be described. FIG. 1 shows a partial cross section of the optical information recording medium.

The information recording medium 25 shown in FIG. 1 has a first dielectric layer 2, a recording layer 4, a second dielectric layer 6, a light absorption correction layer 7, and a reflection layer on one surface of a substrate 1. 8 is formed in this order, and the dummy substrate 10 is further bonded by the adhesive layer 9. The information recording medium having this structure has a wavelength of 66
Recording and reproduction with a laser beam in the red region near 0 nm,
It can be used as 4.7 GB / DVD-RAM. A laser beam 12 is incident on the information recording medium having this configuration from the substrate 1 side, whereby information is recorded and reproduced.
The information recording medium 25 is different from the conventional information recording medium 31 shown in FIG. 9 in that it does not have the first interface layer 103 and the second interface layer 105.

In the first embodiment, both the first dielectric layer 2 and the second dielectric layer 6 are Zr-Zn-S-.
It is an O-based material layer.

Generally, the material of the dielectric layer is 1) transparent, 2) has a high melting point and does not melt during recording, and 3) has good adhesion to the recording layer which is a chalcogenide material. Required to be present. The transparency is a characteristic necessary for allowing the laser light 12 incident from the substrate 1 side to pass through and reach the recording layer 4. This property is particularly required for the first dielectric layer on the incident side. The high melting point is a characteristic necessary for ensuring that the material of the dielectric layer does not mix into the recording layer when irradiated with the laser beam of the peak power level. If the material of the dielectric layer is mixed in the recording layer, the rewriting performance will be significantly deteriorated.
Good adhesion to the recording layer, which is a chalcogenide material, is a characteristic necessary for ensuring the reliability of the information recording medium. Further, as the material of the dielectric layer, the obtained information recording medium is a conventional information recording medium (that is, ZnS-2).
It should be selected so as to have a recording sensitivity equal to or higher than that of a medium in which the interface layer is located between the dielectric layer made of 0 mol% SiO ₂ and the recording layer.

The Zr-Zn-S-O-based material layer is made of ZrO ₂
It is preferably a layer consisting essentially of a mixture of Zn and Sn. ZrO ₂ is transparent and has a high melting point (approximately 2700
C.) and has low thermal conductivity among oxides. Zn-S has good adhesion to the recording layer which is a chalcogenide material. Therefore, by forming the layers containing the mixture of the two kinds of components as the first and second dielectric layers 2 and 6 and forming them so as to be in contact with the recording layer 4 as shown in the drawing, excellent rewriting performance is excellent. Moreover, it is possible to realize the information recording medium 25 having good adhesion between the recording layer and the dielectric layer. The mixture of ZrO ₂ and Zn—S has the above formula (11), that is, (ZrO ₂ ) _X (Zn—
S) Represented by _100-X (mol%). The content of ZrO ₂ (that is, X) is preferably 50 mol% or more in order to secure the repeated rewriting performance. Further, in order to secure the adhesiveness to the recording layer, the content of Zn-S is preferably 20 mol% or more. Therefore,
X is preferably in the range of 50 or more and 80 or less.
Furthermore, as described above, Zn-S is the number of S atoms / Zn.
Is a compound having 1 or more and 2 or less atoms.

The first and second dielectric layers 2 and 6 are
It may be a Zr—Zn—S—O-based material layer containing Si.
The Zr—Zn—S—O-based material layer containing Si is ZrO ₂ ,
It is preferable that consists essentially of a mixture of Zn-S and SiO _2. This mixture has the above formula (21): (ZrO ₂ ) _Y (SiO ₂ ) _Z (Zn-S) _{100-Y- Z}
(Mol%). In this equation, Y and Z
Are in the ranges of 20 ≦ Y ≦ 70, 10 ≦ Z ≦ 50, and 50 ≦ Y + Z ≦ 80, respectively.

SiO₂Containing Zr-Zn-S-O-based material
The layer enhances the recording sensitivity of the information recording medium. Also, SiO
₂The recording sensitivity can be adjusted by adjusting the ratio of
And are possible. SiO₂To increase the recording sensitivity
In order to₂The content of at least
It is preferably 10 mol% or more. On the other hand, SiO
₂When the content of P is large, the adhesion to the recording layer 4 becomes poor.
Therefore, SiO₂Content of 50mol% or less
preferable. ZrO₂And the function of Zn-S is
As described in and be mixed in the proper proportions.
Therefore, the performance of the information recording medium is made appropriate. Zr
O₂-SiO₂-(Zn-S) mixture with the recording layer
In order to secure adhesion, (Zn-S) is 20 mol%
The above is preferably included. In addition, S of the recording layer 4
The content of (Zn-S) is 50 m so that diffusion does not occur.
It is preferably ol% or less. Therefore, the formula (2
In 1), the range of Y + Z is 50 or more and 80 or less.
Preferably.

The Zr-Zn-S-O-based material layer containing SiO ₂ may contain ZrO ₂ and SiO ₂ in substantially equal proportions. In that case, ZrO ₂ and SiO ₂ preferably form ZrSiO ₄ . The mixture in which ZrSiO ₄ is formed has the above formula (22), that is, (ZrSiO 4
₄ ) _A (Zn-S) _100-A (mol%). In this formula, A is in the range of 33 ≦ A ≦ 67.

ZrSiO ₄ is transparent and has a high melting point (about 2
(550 ° C.) and has a low thermal conductivity among oxides. Therefore, a layer made of a combination of ZrSiO ₄ and Zn—S having good adhesion to the recording layer is used as the first dielectric layer 2 and / or the second dielectric layer 6 so as to be in contact with the recording layer 4. By disposing the information recording medium 25, it is possible to realize the information recording medium 25 that has excellent rewriting performance and good adhesion between the recording layer and the dielectric layer. In order to secure good rewriting performance, Z
_{rSiO 4 - (Zn-S)} ZrSiO 4 content in the 33
It is preferably at least mol%. In order to ensure good adhesion, the Zn-S content is preferably 33 mol% or more. Therefore, in the above formula (22), A is 3
It is preferably within the range of 3 ≦ A ≦ 67.

Further, in the Zr-Zn-S-O-based material layer, the number of S atoms may be larger than the number of Zn atoms. In that case, it is preferable that the number of S atoms is not more than twice the number of Zn atoms. The larger the number of S atoms, the better the adhesion between the recording layer and the Zr—Zn—S—O-based material layer. It is considered that this is because the surplus S that does not bond with Zn plays a role of improving the adhesiveness between the recording layer and the layer. On the other hand, as the number of S atoms increases, more S diffuses into the recording layer, so that the crystallization performance of the recording layer deteriorates or an optical change (| Rc-R
a |) becomes small. Therefore, (number of S atoms) /
The ratio of (the number of Zn atoms) must be selected in consideration of the adhesion to the recording layer and the degree of diffusion of S into the recording layer.

The composition of the oxide sulfide mixed dielectric layer can be measured by, for example, X-ray microanalyzer (XMA) or Rutherford backscattering (RBS), and the structure is analyzed by, for example, X-ray diffraction. be able to.

Analysis of the composition yields atomic% of each element contained. For example, in the material represented by the formula (11), (the number of S atoms) / (the number of Zn atoms) = 1, and when X = 50, the elemental composition is approximately Zr ₂₀ O _40.
It becomes Zn ₂₀ S ₂₀ (atomic%). Also, (number of S atoms) /
When (number of Zn atoms) = 2 and X = 80, the composition is approximately Zr _26.7 O _53.3 Zn _6.7 S
It becomes _13.3 (atomic%). All of these elemental compositions satisfy the ranges of B, C, D and B + C + D in the formula (1).

In addition, the material represented by the formula (21)
And (the number of S atoms) / (the number of Zn atoms) = 1, and
When Y = 20 and Z = 30, the elemental composition is
Zr ₈Si₁₂O₄₀Zn₂₀S₂₀(Atomic%). Well
In addition, (the number of S atoms) / (the number of Zn atoms) = 2, and
When Y = 70 and Z = 10, the elemental composition is
Zr_23.3Si_3.3O_53.3Zn_6.7S_13.4(Atomic%)
It All of these compositions have E, F, and G of the formula (2).
And H, and E + F + G + H.

In the material represented by the formula (22), (S
Atom number) / (Zn atom number) = 1, and A = 3
When it is 3, the elemental composition is approximately Zr _9.9 Si _9.9 O
It becomes _39.8 Zn _20.2 S _20.2 (atomic%). Further, when (the number of S atoms) / (the number of Zn atoms) = 2 and A = 67, the elemental composition is approximately Zr _13.4 Si _13.4 O _53.4 Z.
It becomes n _6.6 S _13.2 (atomic%).

First dielectric layer 2 and second dielectric layer 6
By changing each optical path length (that is, the product nd of the refractive index n of the dielectric layer and the film thickness d of the dielectric layer), the optical absorption rate Ac (%) of the recording layer 4 in the crystal phase is When the light absorption rate Aa (%) of the recording layer 4 in the crystalline phase, the light reflection rate Rc (%) of the information recording medium 25 when the recording layer 4 is in the crystalline phase, and when the recording layer 4 is in the amorphous phase Of the information recording medium 25 of Ra
(%), It has a function of adjusting the phase difference Δφ of light of the information recording medium 25 between the portion where the recording layer 4 is the crystalline phase and the portion where the recording layer 4 is the amorphous phase. Increase the playback signal amplitude of the recording mark,
In order to improve the signal quality, the reflectance difference (| Rc-Ra
|) Or the reflectance ratio (Rc / Ra) is desirably large. In addition, A is set so that the recording layer 4 absorbs the laser beam.
It is desirable that c and Aa are also large. The optical path lengths of the first dielectric layer 2 and the second dielectric layer 6 are determined so that these conditions are simultaneously satisfied. The optical path length satisfying those conditions can be accurately determined by calculation based on, for example, the matrix method (see, for example, Hiro Kubota, "Wave Optics", Iwanami Shinsho, 1971, Chapter 3).

As described above, Zr-Zn-S-
The O-based material has a different refractive index depending on its composition.
The material represented by the above formula (11) has a refractive index of 2.3 to 2.4, and the material represented by the above formula (21) is 1.8.
The material represented by the formula (22) has a refractive index of 1.8 to 2.1. The refractive index of the dielectric layer is n, the film thickness is d (nm), and the wavelength of the laser beam 12 is λ.
(Nm), the optical path length nd is represented by nd = aλ. Here, a is a positive number. In order to increase the reproduction signal amplitude of the recording mark of the information recording medium 25 and improve the signal quality, for example, 15% ≦ Rc and Ra ≦ 2% are preferable. Further, in order to eliminate or reduce the mark distortion due to rewriting, it is preferable that 1.1 ≦ Ac / Aa. The optical path lengths (aλ) of the first dielectric layer 2 and the second dielectric layer 6 were accurately obtained by calculation based on the matrix method so that these preferable conditions were satisfied at the same time. The thickness d of the dielectric layer was determined from the obtained optical path length (aλ) and λ and n. As a result, the first
The thickness of the dielectric layer 2 is preferably 100 nm to 200 nm.
It was found that the thickness was nm, and more preferably 130 nm to 170 nm. Further, it has been found that the thickness of the second dielectric layer 6 is preferably 20 nm to 70 nm, more preferably 30 nm to 60 nm.

The substrate 1 is usually a transparent disc-shaped plate. On the surface where the dielectric layer and the recording layer are formed,
A guide groove for guiding the laser light may be formed.
When the guide groove is formed in the substrate, the groove portion and the land portion are formed when the cross section of the substrate is viewed. It can be said that the groove portion is located between two adjacent land portions. Therefore, the surface on which the guide groove is formed has the top surface and the bottom surface connected by the side wall. In this specification, the bottom surface is called a "groove surface" and the top surface is called a "land surface". Therefore, in FIGS. 1 to 6, the surface 23 corresponds to the groove surface and the surface 24 corresponds to the land surface. In the direction of the laser beam 12, the groove surface is always on the side closer to the laser beam 12, and the land surface is always on the side farther from the laser beam. The recording marks are recorded on the surface of the recording layer corresponding to the groove surface (groove recording), on the surface of the recording layer corresponding to the land surface (land recording), or in the recording layer. Data is recorded on the surface of the recording layer corresponding to both surfaces (land-groove recording). In the embodiment shown in FIG. 1, the groove surface 23 of the substrate 1
The step difference between the land surface 24 and the land surface 24 is preferably 40 nm to 60 nm. Also in the substrate 1 forming the information recording medium of the modes shown in FIGS. 2, 3 and 6 which will be described later, it is preferable that the step difference between the groove surface 23 and the land surface 24 is within this range. In addition, it is desirable that the surface on which no layer is formed be smooth. As the material of the substrate 1, polycarbonate, amorphous polyolefin or PMMA
Resins such as, or glass. Polycarbonate is preferably used in consideration of moldability, price, and mechanical strength. In the illustrated form,
The substrate 1 has a thickness of about 0.5 to 0.7 mm.

The recording layer 4 is a layer in which a recording mark is formed by causing phase transformation between a crystalline phase and an amorphous phase by irradiation of light or application of electric energy. If the phase transformation is reversible, it can be erased or rewritten.
As the reversible phase change material, G which is a high-speed crystallization material
It is preferable to use e-Sb-Te or Ge-Sn-Sb-Te. Specifically, Ge-Sb-Te case is preferably a GeTe-Sb ₂ Te ₃ pseudo-binary system composition, in which _{case, 4Sb 2 Te 3 ≦ GeTe ≦} 25Sb
₂ Te ₃ is preferred. GeTe <4Sb ₂ Te ₃
In this case, the change in the amount of reflected light before and after recording is small, and the quality of the read signal deteriorates. In the case of 25Sb ₂ Te ₃ <GeTe, the volume change between the crystalline phase and the amorphous phase is large, and the rewriting performance is deteriorated. Ge-Sn-Sb-Te is
Crystallization rate is faster than Ge-Sb-Te. Ge-Sn
—Sb-Te is, for example, GeTe—Sb ₂ Te _{3 in which} a part of Ge in the pseudo binary system composition is replaced with Sn. In the recording layer 4, the Sn content is preferably 20 atomic% or less. If it exceeds 20 atomic%, the crystallization rate is too fast, the stability of the amorphous phase is impaired, and the reliability of the recording mark is reduced. The Sn content can be adjusted according to the recording conditions.

The recording layer 4 is made of Ge-Bi-Te, G
It can also be formed of a Bi-containing material such as e-Sn-Bi-Te, Ge-Sb-Bi-Te, or Ge-Sn-Sb-Bi-Te. Bi is easier to crystallize than Sb. Therefore, the crystallization rate of the recording layer can also be improved by substituting Bi for at least part of Sb.

Ge-Bi-Te is GeTe and Bi ₂ T.
It is a mixture of e ₃ . In this mixture, 8 Bi ₂ T
It is preferable that e ₃ ≦ GeTe ≦ 25Bi ₂ Te ₃ . In the case of GeTe <8Bi ₂ Te ₃ , the crystallization temperature lowers, and the record storability tends to deteriorate. 25Bi ₂ Te ₃ <
In the case of GeTe, the volume change between the crystalline phase and the amorphous phase is large, and the rewriting performance is deteriorated.

Ge-Sn-Bi-Te is Ge-Bi-
This corresponds to the case where a part of Ge of Te is replaced with Sn. S
It is possible to control the crystallization rate according to the recording conditions by adjusting the substitution concentration of n. Sn substitution is more suitable for fine adjustment of the crystallization rate of the recording layer than Bi substitution. In the recording layer, the Sn content is preferably 10 atomic% or less. If it exceeds 10 atomic%, the crystallization rate becomes too fast, so that the stability of the amorphous phase is impaired and the storage stability of the record mark is deteriorated.

Ge-Sn-Sb-Bi-Te is Ge-
Part of Ge in Sb-Te is replaced with Sn, and
It corresponds to a part of which is replaced with Bi. This is GeT
e, SnTe, Sb₂Te₃And Bi₂Te₃To a mixture of
Equivalent to. In this mixture, Sn substitution concentration and Bi
Adjust the substitution concentration to adjust the crystallization speed according to the recording conditions.
It is possible to control. Ge-Sn-Sb-Bi-
In Te, 4 (Sb-Bi)₂Te₃≤ (Ge-S
n) Te ≦ 25 (Sb-Bi)₂Te₃Preferred to be
Good (Ge-Sn) Te <4 (Sb-Bi)₂Te₃of
If the amount of reflected light before and after recording is small, the read signal
No. quality deteriorates. 25 (Sb-Bi) ₂Te₃<(Ge
In the case of -Sn) Te, the volume change between the crystalline phase and the amorphous phase is
The repetitive rewriting performance is deteriorated. Also record
Bi content in the layer is 10 atomic% or less
Is preferable, and the Sn content is 20 atomic% or less.
Is preferred. The contents of Bi and Sn are each within this range.
Within the range, good storage stability of recording marks can be obtained.

Other materials that cause reversible phase transformation are Ag-In-Sb-Te and Ag-In-Sb-.
Ge-Sb-T containing Te-Ge and Sb in 70 atomic% or more
e.

As an irreversible phase change material, Japanese Patent Publication No. 7-25209 (Patent No. 2006849).
It is preferred to use TeOx + α (α is Pd, Ge etc.) as disclosed in US Pat. The information recording medium whose recording layer is an irreversible phase change material is a so-called write-once type in which recording can be performed only once. Even in such an information recording medium, there is a problem that atoms in the dielectric layer are diffused into the recording layer due to heat at the time of recording and the signal quality is deteriorated. Therefore, the present invention is preferably applied not only to a rewritable information recording medium but also to a write-once type information recording medium.

The recording layer 4 has a thickness of 1 as described above.
It is preferably 5 nm or less, and more preferably 12 nm or less.

As described above, the light absorption correction layer 7 adjusts the ratio Ac / Aa of the light absorption rate Ac when the recording layer 4 is in the crystalline state and the light absorption rate Aa when it is in the amorphous state. , It works to prevent the mark shape from being distorted during rewriting.
The light absorption correction layer 7 is preferably formed of a material having a high refractive index and appropriately absorbing light. For example, the light absorption correction layer 7 can be formed using a material having a refractive index n of 3 or more and 6 or less and an extinction coefficient k of 1 or more and 4 or less. Specifically, amorphous Ge alloys such as Ge—Cr and Ge—Mo, amorphous Si alloys such as Si—Cr, Si—Mo, and Si—W, Te compounds, and Ti and Zr. , Nb,
It is preferable to use a material selected from crystalline metals such as Ta, Cr, Mo, W, SnTe, and PbTe, semimetals, and semiconductor materials. The thickness of the light absorption correction layer 7 is preferably 20 nm to 80 nm and is 30 n.
It is more preferably m to 50 nm.

The reflective layer 8 optically increases the amount of light absorbed in the recording layer 4, and thermally thermally diffuses the heat generated in the recording layer 4 to rapidly cool the recording layer 4 and to make it amorphous. It has the function of facilitating qualification. Furthermore, the reflective layer 8 protects the multilayer film including the recording layer 4 and the dielectric layers 2 and 6 from the use environment. Examples of the material of the reflective layer 8 include Al, Au, A
Examples include simple metal materials having high thermal conductivity such as g and Cu. The reflective layer 8 is for the purpose of improving its moisture resistance.
And / or thermal conductivity or optical properties (eg,
For the purpose of adjusting the light reflectance, the light absorption rate or the light transmittance, a material obtained by adding one or more other elements to the one or more elements selected from the above metal materials is used. May be formed. Specifically, Al-Cr, Al-T
i, Ag-Pd, Ag-Pd-Cu, Ag-Pd-T
An alloy material such as i or Au—Cr can be used. All of these materials are excellent materials having excellent corrosion resistance and a rapid cooling function. For the same purpose, the reflective layer 8 is 2
It can also be achieved by forming the above layers. The thickness of the reflective layer 8 is preferably 50 to 180 nm,
More preferably, it is 60 nm to 100 nm.

In the illustrated information recording medium 25, the adhesive layer 9 is provided to adhere the dummy substrate 10 to the reflective layer 8. The adhesive layer 9 is a material having high heat resistance and adhesiveness,
For example, it may be formed using an adhesive resin such as an ultraviolet curable resin. Specifically, the adhesive layer 9 may be formed of a material containing an acrylic resin as a main component or a material containing an epoxy resin as a main component. If necessary, before forming the adhesive layer 9, a thickness of 5 to 20 μm made of an ultraviolet curable resin is used.
This protective layer may be provided on the surface of the reflective layer 8. The thickness of the adhesive layer 9 is preferably 15 to 40 μm, more preferably 20 to 35 μm.

The dummy substrate 10 enhances the mechanical strength of the information recording medium 25 and protects the laminated body from the first dielectric layer 2 to the reflective layer 8. The preferred material for the dummy substrate 10 is the same as the preferred material for the substrate 1. In the information recording medium 25 to which the dummy substrate 10 is attached, the dummy substrate 10 and the substrate 1 are formed of substantially the same material and have the same thickness so that mechanical warp, distortion, etc. do not occur. Is preferred.

The information recording medium of the first embodiment is a single-sided structure disc having one recording layer. The information recording medium of the present invention may have two recording layers. For example, what is laminated up to the reflective layer 8 in the first embodiment is used as the reflective layer 8
An information recording medium having a double-sided structure can be obtained by making them face each other and bonding them via an adhesive layer. In this case, the two laminated bodies are bonded to each other by forming an adhesive layer with a slow-acting resin and utilizing the action of pressure and heat. When the protective layer is provided on the reflective layer 8, the laminated body having the protective layer formed thereon is laminated with the protective layers facing each other to obtain an information recording medium having a double-sided structure.

Subsequently, the information recording medium 25 of the first embodiment
A method of manufacturing the will be described. In the information recording medium 25, the substrate 1 on which guide grooves (groove surface 23 and land surface 24) are formed is arranged in a film forming apparatus, and the first dielectric layer 2 is formed on the surface of the substrate 1 on which the guide groove is formed. A step of forming a film (step a), a step of forming a recording layer 4 (step b), a step of forming a second dielectric layer 6 (step c), a step of forming a light absorption correction layer 7 ( By sequentially performing the step d) and the step of forming the reflective layer 8 (step e), the step of forming the adhesive layer 9 on the surface of the reflective layer 8 and the step of bonding the dummy substrate 10 , Manufactured. In the present specification including the following description, the term “surface” with respect to each layer refers to an exposed surface (surface perpendicular to the thickness direction) when each layer is formed, unless otherwise specified. And

First, the step a of forming the first dielectric layer 2 on the surface of the substrate 1 on which the guide groove is formed is carried out. Step a is performed by sputtering. The sputtering is performed using a high frequency power source in an Ar gas atmosphere or a mixed gas atmosphere of Ar gas and oxygen.

As the sputtering target used in the step a, the above formula (110), that is, (Zr
O ₂ ) _x (Zn-S) _100-x (mol%), x
However, a target consisting essentially of a material in the range 50 ≦ X ≦ 80 can be used. According to this target
A layer substantially consisting of the material represented by the above formula (11) is formed.

Alternatively, the sputtering target is
The above formula (210), that is, (ZrO ₂ ) _y (SiO ₂ )
_z (Zn-S) _100-yz (mol%), y
And z are 20 ≦ y ≦ 70 and 10 ≦ z, respectively.
Targets in the range ≦ 50 and consisting essentially of 50 ≦ y + z ≦ 80 can be used. According to this target, a layer substantially made of the material represented by the above formula (21) is formed.

Alternatively, the sputtering target is
The above formula (220), that is, (ZrSiO ₄ ) _a (Zn-
S) is represented by _100-a (mol%), and a is 33 ≦ a ≦ 67.
May substantially consist of materials within the range. According to this target, a layer substantially made of the material represented by the formula (22) is formed.

Then, step b is carried out to form the recording layer 4 on the surface of the first dielectric layer 2. Step b is also performed by sputtering. The sputtering is performed by using a DC power supply in an Ar gas atmosphere or Ar gas and N 2.
Conduct in a mixed gas atmosphere of ₂ gases. The sputtering target is Ge-Sb-Te, Ge-Sn-Sb-.
Te, Ge-Bi-Te, Ge-Sn-Bi-Te, G
e-Sb-Bi-Te, Ge-Sn-Sb-Bi-T
Of e, Ag-In-Sb-Te and Sb-Te,
A material containing any one material is used. The recording layer 4 after the film formation is in an amorphous state.

Next, step c is carried out to form a second dielectric layer 6 on the surface of the recording layer 4. Step c is performed in the same manner as step a. The second dielectric layer 6 may be formed by using a sputtering target made of a material different from that of the first dielectric layer 2.

Then, step d is carried out to form a light absorption correction layer 7 on the surface of the second dielectric layer 6. In step d, sputtering is performed using a DC power supply or a high frequency power supply. G as a sputtering target
Amorphous Ge alloys such as e-Cr and Ge-Mo, Si
Amorphous Si alloys such as —Cr and Si—Mo, Te compounds, and Ti, Zr, Nb, Ta, Cr, Mo,
A material selected from crystalline metals such as W, SnTe, and PbTe, semimetals, and materials selected from semiconductor materials is used. Sputtering is generally performed in an Ar gas atmosphere.

Next, step e is carried out to carry out the light absorption correction layer 7
The reflective layer 8 is formed on the surface of the. Step e is performed by sputtering. Sputtering is carried out in an Ar gas atmosphere using a DC power supply or a high frequency power supply.
As the sputtering target, Al-Cr, Al
-Ti, Ag-Pd, Ag-Pd-Cu, Ag-Pd-
A material made of an alloy material such as Ti or Au-Cr can be used.

As described above, the steps a to e are all sputtering steps. Therefore, the steps a to e are
The target may be sequentially changed and continuously carried out in one sputtering apparatus. Alternatively, steps a to
e may be carried out using independent sputtering devices.

After forming the reflective layer 8, the substrate 1 in which the first dielectric layer 2 to the reflective layer 8 are sequentially stacked is taken out from the sputtering apparatus. Then, an ultraviolet curable resin is applied to the surface of the reflective layer 8 by, for example, a spin coating method. The dummy substrate 10 is brought into close contact with the applied ultraviolet curable resin, and ultraviolet rays are irradiated from the dummy substrate 10 side to cure the resin, and the bonding step is completed.

After the bonding process is completed, an initialization process is carried out if necessary. The initialization step is a step of irradiating the recording layer 4 in an amorphous state with, for example, a semiconductor laser to raise the temperature above the crystallization temperature to crystallize. The initialization process may be performed before the bonding process. In this way, the information recording medium 25 of the first embodiment can be manufactured by sequentially performing the steps a to e, the adhesive layer forming step, and the dummy substrate bonding step.

(Embodiment 2) As Embodiment 2 of the present invention, another example of an optical information recording medium for recording and reproducing information using a laser beam will be described. FIG. 2 shows a partial cross section of the optical information recording medium.

The information recording medium 26 shown in FIG. 2 has the first dielectric layer 2, the recording layer 4, the second interface layer 105, the second dielectric layer 106, and the light absorbing layer on one surface of the substrate 1. Correction layer 7,
The reflective layer 8 is formed in this order, and the dummy substrate 10 is further bonded by the adhesive layer 9. The information recording medium 26 shown in FIG. 2 is different from the conventional information recording medium 31 shown in FIG. 9 in that it does not have the first interface layer 103. The information recording medium 26 is the information recording medium of the first embodiment shown in FIG. 1 in that the second dielectric layer 106 is laminated on the recording layer 4 via the second interface layer 105. Different from 25. In the information recording medium 26, the first dielectric layer 2 is made of Zr as in the first embodiment.
-Zn-S-O-based material layer. 2, the same reference numerals as those used in FIG. 1 represent the same elements and are formed by the materials and methods described with reference to FIG. Therefore, detailed description of the elements already described with reference to FIG. 1 will be omitted.

The information recording medium 26 of this form is
The electric layer 106 was used in the conventional information recording medium.
ZnS-20 mol% SiO₂Corresponding to the structure formed in
It Therefore, the second interfacial layer 105 is repeatedly recorded.
Caused by the recording between the second dielectric layer 106 and the recording layer 4.
It is provided to prevent the mass transfer. Second interface layer
105 is Si-N, Al-N, Zr-N, Ti-N,
Nitride such as Ge-N, Cr-N or Ta-N, or
Nitric oxide containing these, or Al₂O₃, Cr₂O₃,
HfO₂, SiO₂, Ta₂O_Five, TiO₂Or ZrO₂
Such as oxides, carbon, or carbides such as SiC, or L
aF₃And the like. Or these
Compounds mixed, Ge-Cr-N, ZrO₂-Cr₂O
₃, ZrO₂-SiO₂-C, ZrO₂-SiO₂-Cr₂O
₃, ZrO₂-SiO₂-Cr₂O₃-LaF₃, HfO₂−
SiO₂-Cr₂O₃, Ta₂O_Five-Cr₂O₃, Or Ta₂
O _Five-Cr₂O₃-LaF₃Etc. can also be used. is there
The second interface layer 105 is made of a Zr—Zn—S—O-based material.
It may be a material layer. The thickness of the interface layer is 1 to 10 nm
Is preferable, and more preferably 2 to 5 nm.
Yes. When the thickness of the interface layer is large, it is formed on the surface of the substrate 1.
Light reflection of the laminated body from the first dielectric layer 2 to the reflective layer 8
Rate and light absorptance change, which affects the recording and erasing performance.
Get

Subsequently, the information recording medium 26 of the second embodiment
A method of manufacturing the will be described. In the information recording medium 26, the step of forming the first dielectric layer 2 on the surface of the substrate 1 in which the guide groove is formed (step a), the step of forming the recording layer 4 (step b), and the second step A step of forming the interface layer 105 (step f),
The step of forming the second dielectric layer 106 (step g), the step of forming the light absorption correction layer 7 (step d), and the step of forming the reflective layer 8 (step e) are sequentially performed, and Reflective layer 8
Of forming the adhesive layer 9 on the surface of the substrate, and the dummy substrate 1
It is manufactured by carrying out the step of bonding 0. The steps a, b, d, and e are the same as those described in connection with the first embodiment, and therefore the description thereof is omitted here. Hereinafter, only steps that are not performed in manufacturing the information recording medium of the first embodiment will be described.

Step f is a step which is carried out after forming the recording layer 4 and forms the second interface layer 105 on the surface of the recording layer 4. Sputtering is also performed in step f. Step f may be a reactive sputtering step that is performed in a mixed gas atmosphere of Ar gas and N ₂ gas using a high-frequency power source and a sputtering target containing Ge. According to this reactive sputtering,
An interface layer containing Ge—N is formed on the surface of the recording layer 4.
Alternatively, in step f, a high frequency power source is used and Z
Using a sputtering target containing rO ₂ , Ar
Sputtering is carried out in a gas atmosphere, whereby
An interface layer containing ZrO ₂ may be formed. Alternatively, in step f, a high frequency power source is used and ZrO ₂ —SiO ₂ is used.
Using a sputtering target containing -Cr ₂ O _3,
Sputtering may be performed in an Ar gas atmosphere to form an interface layer containing ZrO ₂ —SiO ₂ —Cr ₂ O ₃ . Alternatively, in step f, a high frequency power supply may be used and a sputtering target containing LaF ₃ may be used to perform sputtering in an Ar gas atmosphere, thereby forming an interface layer containing LaF ₃ .

Next, step g is performed to carry out the second interface layer 1
The second dielectric layer 106 is formed on the surface of 05. In step g, a high frequency power source is used, for example ZnS-2
Sputtering is performed in an Ar gas atmosphere or in a mixed gas atmosphere of Ar gas and O ₂ gas using a sputtering target made of 0 mol% SiO ₂ .
Thereby, a layer made of ZnS-20 mol% SiO ₂ is formed. Then, after the step of attaching the dummy substrate 10 is completed, as described in connection with the first embodiment, the initialization step is performed as necessary to obtain the information recording medium 26.

(Embodiment 3) As Embodiment 3 of the present invention, still another example of an optical information recording medium for recording and reproducing information using a laser beam will be described. Figure 3
A partial cross section of the optical information recording medium is shown in FIG.

The information recording medium 27 shown in FIG. 3 has the first dielectric layer 102 and the first interface layer 1 on one surface of the substrate 1.
03, recording layer 4, second dielectric layer 6, light absorption correction layer 7,
The reflective layer 8 is formed in this order, and the dummy substrate 10 is further bonded by the adhesive layer 9. The information recording medium 27 shown in FIG. 3 is different from the conventional information recording medium 31 shown in FIG. 9 in that it does not have the second interface layer 105. The information recording medium 27 includes the substrate 1 and the recording layer 4.
This is different from the information recording medium 25 of the first embodiment shown in FIG. 1 in that the first dielectric layer 102 and the first interface layer 103 are laminated in this order between the two. Information recording medium 27
In the above, the second dielectric layer 6 is a Zr—Zn—S—O-based material layer, as in the first embodiment. Others, Figure 3
1, the same reference numerals as those used in FIG. 1 represent the same elements and are formed by the materials and methods described with reference to FIG. Therefore, detailed description of the elements already described in FIG. 1 will be omitted.

The information recording medium 27 of this embodiment corresponds to the structure in which the first dielectric layer 102 is formed of ZnS-20 mol% SiO ₂ used in the conventional information recording medium. Therefore, the first interface layer 103 is provided to prevent the mass transfer that occurs between the first dielectric layer 102 and the recording layer 4 due to repeated recording. The preferable material and thickness of the first interface layer 103 are the same as those of the second interface layer 105 of the information recording medium 26 of the second embodiment described with reference to FIG. Therefore, detailed description thereof will be omitted.

Next, the information recording medium 27 of the third embodiment
A method of manufacturing the will be described. In the information recording medium 27, a step of forming the first dielectric layer 102 on the surface of the substrate 1 in which the guide groove is formed (step h), a step of forming the first interface layer 103 (step i), A step of forming the recording layer 4 (step b),
The step of forming the second dielectric layer 6 (step c), the step of forming the light absorption correction layer 7 (step d), and the step of forming the reflective layer 8 (step e) are sequentially performed, and It is manufactured by performing the step of forming the adhesive layer 9 on the surface of the reflective layer 8 and the step of adhering the dummy substrate 10.
Steps b, c, d, and e are the same as those described in connection with the first embodiment, and therefore the description thereof is omitted here. Hereinafter, only steps that are not performed in manufacturing the information recording medium of the first embodiment will be described.

Step h is a step of forming the first dielectric layer 102 on the surface of the substrate 1. The specific method is the same as step g described in connection with the manufacturing method of the second embodiment. Step i is the first step on the surface of the first dielectric layer 102.
This is a process of forming the interface layer 103 of. The specific method is the same as step f described in connection with the manufacturing method of the second embodiment. Then, after the step of attaching the dummy substrate 10 is completed, the initialization step is performed as necessary as described in connection with the first embodiment, and the information recording medium 27 is obtained.

(Embodiment 4) As Embodiment 4 of the present invention, another example of an optical information recording medium for recording and reproducing information with a laser beam will be described. FIG. 4 shows a partial cross section of the optical information recording medium.

The information recording medium 28 shown in FIG.
A reflective layer 8, a second dielectric layer 6, a recording layer 4, and a first dielectric layer 2 are formed in this order on one surface of No. 1 and a dummy substrate 110 is bonded by an adhesive layer 9. Have. This information recording medium 28 is different from the conventional information recording medium 31 shown in FIG. 9 in that it does not have the first interface layer 103 and the second interface layer 105. Further, the information recording medium having this structure is different from the information recording medium 25 having the structure shown in FIG. 1 in that it does not have the light absorption correction layer 7.

The laser beam 12 is incident on the information recording medium 28 of this structure from the dummy substrate 110 side, and thereby recording and reproducing of information is performed. In order to increase the recording density of the information recording medium, it is necessary to use a laser beam having a short wavelength and further narrow the laser beam to form a small recording mark on the recording layer. In order to narrow the beam, it is necessary to increase the numerical aperture NA of the objective lens. However, as NA increases, the focal position becomes shallower. Therefore, it is necessary to thin the substrate on which the laser light is incident. In the information recording medium 28 shown in FIG. 4, the dummy substrate 110 on the laser light incident side is
Since it is not necessary to function as a support when forming the recording layer and the like, the thickness can be reduced. Therefore, according to this structure, it is possible to obtain the large-capacity information recording medium 28 capable of high-density recording. In particular,
With this configuration, it is possible to obtain an information recording medium having a capacity of 25 GB, which uses laser light in the blue-violet region having a wavelength of about 405 nm for recording and reproduction.

Also in this information recording medium, the first and second dielectric layers 2 and 6 are the same as in the first embodiment.
It is a Zr-Zn-S-O-based material layer. Zr-Zn-S-
The O-based material layer is applied as a dielectric layer regardless of the order of forming the reflective layer and the like and the recording capacity. Zr-Zn-S-
The materials contained in the O-based material layer are as described in relation to the first embodiment, so detailed description thereof will be omitted.

As described above, this information recording medium 28 is
It is suitable for recording and reproducing with laser light of short wavelength. Therefore, the thicknesses of the first and second dielectric layers 2 and 6 are obtained from the preferable optical path length when λ = 405 nm, for example. In order to increase the reproduction signal amplitude of the recording mark of the information recording medium 28 and improve the signal quality, for example, the first dielectric layer 2 and the second dielectric layer 2 and the second dielectric layer 2 satisfy 20% ≦ Rc and Ra ≦ 5%. The optical path length nd of the body layer 6 was strictly determined by calculation based on the matrix method. As a result, the first and second dielectric layers 2 and 6 are formed of the Zr—Zn—S—O-based material having the above-described refractive index.
In that case, the thickness of the first dielectric layer 2 is preferably 30
nm to 100 nm, more preferably 50 nm to 8
It was found to be 0 nm. Further, it has been found that the thickness of the second dielectric layer 6 is preferably 3 nm to 50 nm, more preferably 10 nm to 30 nm.

The substrate 101 is a transparent disc-shaped plate like the substrate 1 of the first embodiment. As the substrate 101, a substrate having a diameter of about 50 mm to 120 mm is used. A guide groove for guiding the laser light may be formed on the surface of the substrate 101 on which the reflective layer and the like are formed. When the guide groove is formed, the surface 23 is called the groove surface 23 and the surface 24 is called the land surface, as in the first embodiment. The step difference between the groove surface 23 and the land surface 24 is preferably 10 nm to 30 nm, and more preferably 15 nm to 25 nm. In addition, it is desirable that the surface on which no layer is formed be smooth. The material of the substrate 101 can be the same as the material of the substrate 1 of the first embodiment. The thickness of the substrate 101 is preferably 0.8 to 1.2 m
It is about m. The preferable thickness of substrate 101 is larger than that of substrate 1 of the first embodiment. This is because the dummy substrate 110 is thin, as will be described later.
This is because it is necessary to secure the strength of the information recording medium in 1.

Like the substrate 101, the dummy substrate 110 is a transparent disc-shaped plate. As described above, according to the configuration shown in FIG. 4, it is possible to record with the laser light of the short wavelength by reducing the thickness of the dummy substrate 110. Therefore, the thickness of the dummy substrate 110 is 40 μm.
It is preferably about 110 μm. More preferably, the total thickness of the adhesive layer 9 and the dummy substrate 110 is 50 μm to 120 μm.

Since the dummy substrate 110 is thin, polycarbonate, amorphous polyolefin, or PMMA is used.
It is preferable to form the above resin, and it is particularly preferable to form the polycarbonate. Further, since the dummy substrate 110 is located on the laser light 12 incident side, it is preferable that the dummy substrate 110 is optically small in birefringence in the short wavelength region.

The reflective layer 8 may be made of the same material as the reflective layer 8 of the first embodiment and may have the same thickness. In the illustrated embodiment, when a material containing Ag is used for the reflective layer 8, the reflective layer 8 preferably has a two-layer structure or a structure including two or more layers. This is to prevent S contained in the second dielectric layer 6 and Ag contained in the reflective layer 8 from forming Ag ₂ S. The reflective layer having a two-layer structure has, for example, a layer made of Ag-Pd-Cu formed on the surface of the substrate 101,
It is formed by forming a layer made of Al-Cr thereon. In this case, the second dielectric layer 6 is Al-Cr.
Formed on the surface of the layer. The Al-Cr layer prevents reaction between S in the second dielectric layer and Ag in the reflective layer. Second
The thickness of the layer located between the dielectric layer 8 and the layer containing Ag is preferably 5 nm or more.

The adhesive layer 9 is preferably formed of a transparent ultraviolet curable resin. The thickness of the adhesive layer 9 is 5 to 15 μm
Is preferred. If the adhesive layer 9 also has the function of the dummy substrate 110 and can be formed to have a thickness of 50 μm to 120 μm, the dummy substrate 110 can be omitted.

Other elements having the same reference numerals as those in the first embodiment are the same as those already described in the first embodiment, and the description thereof will be omitted.

In the modification of the information recording medium of this aspect, for example, only the first dielectric layer is made of Zr-Zn-S-O.
System material layer, and the second dielectric layer is ZnS-20 mol%
It may be formed of SiO ₂ to form a second interface layer between the second dielectric layer and the recording layer. In that case, when the reflective layer contains Ag, it is preferable that the reflective layer has a two-layer structure as described above so that S in the second dielectric layer does not react with Ag in the reflective layer. . In addition, the fourth embodiment
In another modified example of the information recording medium, the second dielectric layer is a Zr—Zn—S—O-based material layer only, and the first dielectric layer is a ZnS—20 mol% SiO ₂ layer. A first interface layer may be formed between the dielectric layer and the recording layer.

Subsequently, the information recording medium 28 of the fourth embodiment
The manufacturing method of will be described. The information recording medium 28 includes a substrate 1 on which guide grooves (groove surface 23 and land surface 24) are formed.
01 is placed in the film forming apparatus, and the step of forming the reflective layer 8 on the surface of the substrate 101 in which the guide groove is formed (step e), the step of forming the second dielectric layer 6 (step c), The step of forming the recording layer 4 (step b) and the step of forming the first dielectric layer 2 (step a) are sequentially performed, and further, the adhesive layer 9 is formed on the surface of the first dielectric layer 2. It is manufactured by carrying out the step of forming and the step of bonding the dummy substrate 110.

First, step e is carried out to form the reflective layer 8 on the surface of the substrate 101 on which the guide groove is formed. Process e
The specific method for carrying out is as described in connection with the first embodiment. Next, step c, step b, and step a are performed in this order. The specific method of performing steps c, b, and a is as described in connection with the first embodiment. In the method of manufacturing the information recording medium of this embodiment, the order of performing the steps is different from that in the method of manufacturing the information recording medium of the first embodiment.

After forming the first dielectric layer 2, the reflective layer 8 is formed.
To the first dielectric layer 2 are sequentially laminated on the substrate 101,
Take out from the sputtering device. Then, an ultraviolet curable resin is applied onto the first dielectric layer 2 by, for example, a spin coat method. The dummy substrate 110 is brought into close contact with the applied ultraviolet curable resin to expose the dummy substrate 11 to ultraviolet rays.
The resin is cured by irradiation from the 0 side, and the bonding step is completed. The step of bonding the dummy substrate 110 can be omitted by forming the adhesive layer 9 to have a thickness of 60 μm to 120 μm and irradiating the adhesive layer 9 with ultraviolet rays.

After the bonding step is completed, an initialization step is carried out if necessary. The method of the initialization process is as described in relation to the first embodiment.

(Embodiment 5) As Embodiment 5 of the present invention, still another example of an optical information recording medium for carrying out recording and reproduction using a laser beam will be described. FIG. 5 shows a partial cross section of the optical information recording medium.

The information recording medium 29 shown in FIG.
The second information layer 22, the intermediate layer 16, and the first information layer 21 are formed in this order on one surface of No. 1, and the dummy substrate 110 is further laminated via the adhesive layer 9. More specifically, the second information layer 22 includes the second reflective layer 20, the fifth dielectric layer 19, the second recording layer 18, and the fourth dielectric layer 17 on one surface of the substrate 101. It is formed in order. The intermediate layer 16 is formed on the surface of the fourth dielectric layer 17. The first information layer 21 has the third dielectric layer 15, the first reflective layer 14, the second dielectric layer 6, the first recording layer 13, and the first dielectric layer on the surface of the intermediate layer 16. Body layer 2
Are formed in this order. Also in this form, the laser light 12 is incident from the dummy substrate 110 side. Further, in the information recording medium of this aspect, information can be recorded in each of the two recording layers. Therefore, according to this configuration, the capacity is about twice that of the fourth embodiment,
An information recording medium can be obtained. Specifically, according to this configuration, for example, it is possible to obtain an information recording medium having a capacity of 50 GB, which uses laser light in the blue-violet region near the wavelength of 405 nm for recording and reproduction.

Recording / reproduction on the first information layer 21 is performed by the laser beam 12 that has passed through the dummy substrate 110. Recording / reproduction on the second information layer 22 is performed by the dummy substrate 1
The laser light 12 that has passed through the first information layer 21 and the intermediate layer 16 is used.

Also in the information recording medium 29 of the form shown in FIG. 5, the fifth dielectric layer 19, the fourth dielectric layer 17, and the second dielectric layer 17 are formed.
The dielectric layer 6 and the first dielectric layer 2 of
It is preferably an r-Zn-S-O-based material layer. If this material layer is used, between the first recording layer 13 and the first dielectric layer 2, between the first recording layer 13 and the second dielectric layer 6, and between the second recording layer 18 And the fourth dielectric layer 17, and the interface layer between the second recording layer 18 and the fifth dielectric layer 19 becomes unnecessary. The specific material of the Zr—Zn—S—O-based material layer is as described in relation to the first embodiment, so detailed description thereof will be omitted.

Fifth dielectric layer 19 and second dielectric layer 6
Functions as a heat insulating layer between the reflective layer and the recording layer. The thickness of the fifth and second dielectric layers 19 and 6 is preferably 3 nm to 50 nm, more preferably 10 nm.
~ 30 nm.

The film thicknesses of the fourth dielectric layer 17 and the first dielectric layer 2 are preferably 30 nm to 100 nm, more preferably 50 nm to 80 nm.

As described above, also in the information recording medium having the single-sided two-layer structure as shown in FIG. 5, the dielectric layers located on both sides of the recording layer are made of Zr—Zn—S—O type material layers, The dielectric layer can be formed so as to be in direct contact with the recording layer without interposing the interface layer. Therefore, according to the present invention, it is possible to reduce the number of layers constituting the entire information recording medium having a single-sided two-layer structure.

The third dielectric layer 15 includes the intermediate layer 16 and the first dielectric layer 15.
Between the reflective layer 14 and the reflective layer 14. Third dielectric layer 15
Is preferably transparent and has a high refractive index (2.3 ≦ n) so as to have a function of increasing the light transmittance of the first information layer 21. The third dielectric layer 15 is preferably made of a material having a higher thermal conductivity so as to have a function of quickly diffusing the heat of the first recording layer 13, like the reflective layer. Materials satisfying these conditions are TiO ₂ and Cr ₂ O ₃ . Further, a mixture of ZrO ₂ and Cr ₂ O ₃ , in which the proportion of Cr ₂ O ₃ is 40 mol% or more, may be used. The thickness of the third dielectric layer 15 is 1
It is preferably 0 nm to 30 nm.

The substrate 101 is the substrate 101 of the fourth embodiment.
Is similar to. Therefore, here, the substrate 10
A detailed description of 1 will be omitted.

Second reflective layer 20 is similar to reflective layer 8 of the first embodiment. In addition, the second recording layer 18 is
This is the same as the recording layer 4 of the first embodiment. Therefore, here, the second reflective layer 20 and the second recording layer 1
A detailed description of No. 8 will be omitted.

The intermediate layer 16 is provided so that the focal position of the laser light on the first information layer 21 and the focal position on the second information layer 22 are significantly different. A guide groove is formed in the intermediate layer 16 on the side of the first information layer 21 as necessary. The intermediate layer 16 can be formed of an ultraviolet curable resin. The intermediate layer 16 is preferably transparent to the light having the wavelength λ to be recorded / reproduced so that the laser light 12 reaches the second information layer 22 efficiently. Middle layer 16
Must have a depth of focus ΔZ or more determined by the numerical aperture NA of the objective lens and the laser light wavelength λ.
ΔZ can be approximated by ΔZ = λ / {2 (NA) ² }. λ
= 405 nm, NA = 0.85, ΔZ = 0.28μ
m. Furthermore, since the range of ± 0.3 μm of this value is included in the range of the depth of focus, the thickness of the intermediate layer 16 is 0.8 μm.
It is necessary that the thickness is m or more. The thickness of the intermediate layer 16 is the same as that of the first recording layer 13 and the second information layer 21 of the first information layer 21.
The distance between the second recording layers 18 of the information layers 22 is within the allowable substrate thickness tolerance of the objective lens used together with the thickness of the dummy substrate 110 so that the distance between the second recording layers 18 is within the range where the objective lens can collect light. Preferably. Therefore, the thickness of the intermediate layer is preferably 10 μm to 40 μm.

The intermediate layer 16 may be formed by laminating a plurality of resin layers if necessary. Specifically, it may have a two-layer structure of a layer for protecting the fourth dielectric layer 17 and a layer having a guide groove.

The first reflective layer 14 has a function of quickly diffusing the heat of the first recording layer 13. Further, when recording / reproducing the second information layer 22, the laser beam 12 that has passed through the first information layer 21 is used, so the first information layer 21 must have a high light transmittance as a whole, which is preferable. Is
It has a light transmittance of 45% or more. Therefore, the material and thickness of the first reflective layer 14 are limited as compared with the second reflective layer 20. In order to reduce the light absorption of the first reflective layer 14, the first reflective layer 14 has a small thickness,
It is desirable to have a low extinction coefficient and a high thermal conductivity. Specifically, the first reflective layer 14 is preferably an alloy containing Ag and is formed so as to have a film thickness of 5 nm or more and 15 nm or less. When the first reflective layer 14 contains Ag and the second dielectric layer 6 is a Zr-Zn-S-O-based material layer, Ag in the first reflective layer 14 and the second dielectric layer In order to prevent S in layer 6 from reacting with these 2
It is preferable to provide a substantially transparent layer containing no S of about 5 nm to 10 nm between the two layers. Such a layer may be, for example, TiO ₂ , Cr ₂ O ₃ , or Cr ₂ O ₃
-ZrO formed by _{2 (40mol% ≦ Cr 2 O} 3).

The first recording layer 13 is also the first information layer 21.
Of the second recording layer 18 in order to secure a high light transmittance of
By comparison, its material and film thickness are limited. First note
The recording layer 13 preferably has a transmittance in its crystalline phase and
The average transmittance of the amorphous phase is 45% or more
To form. Therefore, the film thickness of the first recording layer 13 is
It is preferably 7 nm or less. The first recording layer 13
Even if the material to be composed has such a thin film thickness, it will melt
Good quality recording marks are formed by rapid cooling
The signal can be reproduced and the recording medium is
Selected to ensure that the
It Specifically, GeTe-S which is a reversible phase change material
b₂Te₃Ge-Sb-Te, or Ge, like system materials
Te-Sb ₂Te₃Part of Ge of the system material was replaced with Sn
Ge-B containing Ge-Sn-Sb-Te or Bi
i-Te, Ge-Sn-Bi-Te, Ge-Sb-Bi
-Te, or Ge-Sn-Sb-Bi-Te,
It is preferable to form one recording layer 13.

Like the adhesive layer 9 of the fourth embodiment, the adhesive layer 9 is preferably formed of a transparent ultraviolet curable resin. The thickness of the adhesive layer 9 is preferably 5 to 15 μm.

The dummy substrate 110 is similar to the dummy substrate 110 of the fourth embodiment. Therefore, a detailed description of the dummy substrate is omitted here. Also in this embodiment, if the adhesive layer 9 also has the function of the dummy substrate 110 and can be formed to have a thickness of 50 μm to 120 μm, the dummy substrate 110 can be omitted.

In the above, the number of information layers having recording layers is 2
The information recording medium having the structure described above has been described. The information recording medium having a plurality of recording layers is not limited to this structure, and may have a structure including three or more information layers. Also,
A modification of the illustrated form is, for example, of the two information layers,
One is an information layer having a recording layer that causes a reversible phase transformation, and one is an information layer that has a recording layer that causes an irreversible phase transformation.

In an information recording medium having three information layers, one of the three information layers is a read-only information layer, and one is an information layer having a recording layer which causes reversible phase transformation, It is also possible to use one as an information layer having a recording layer that causes an irreversible phase transformation. As described above, there are various types of information recording media having two or more information layers. In either form, the dielectric layer is made of Zr-Zn-
By using the S—O based material layer, it is possible to eliminate the need for providing an interface layer between the recording layer and the dielectric layer.

Then, the information recording medium 29 of the fifth embodiment.
A method of manufacturing the will be described. In the information recording medium 29, the step of forming the second reflective layer 20 on the substrate 101 (step j),
The step of forming the fifth dielectric layer 19 (step k), the step of forming the second recording layer 18 (step l), and the step of forming the fourth dielectric layer 17 (step m). And the step of forming the intermediate layer 16 on the surface of the fourth dielectric layer 17, and then forming the third dielectric layer 15 on the surface of the intermediate layer 16 (step n). , The first reflective layer 14
Film forming step (step o), forming the second dielectric layer 6 (step p), forming the first recording layer 13 (step q), and the first dielectric layer 2 is sequentially performed, and further, a step of forming the adhesive layer 9 on the surface of the first dielectric layer 2 and the dummy substrate 11 are performed.
It is manufactured by carrying out the step of bonding 0.

Steps j to m correspond to the step of forming the second information layer 22. Step j is a step of forming the second reflective layer 20 on the surface of the substrate 101 on which the guide groove is formed.
Process j is performed in the same manner as process e of the first embodiment. Next, step k is performed to form a fifth dielectric layer 19 on the surface of the second reflective layer 20. Step k is performed in the same manner as step c in the first embodiment. Next, step l
Then, the second recording layer 18 is formed on the surface of the fifth dielectric layer 19. Step l is performed in the same manner as step b of the first embodiment. Finally, step m is performed to form the fourth dielectric layer 17 on the surface of the second recording layer 18. Step m is performed in the same manner as step a in the first embodiment.

The substrate 101 on which the second information layer 22 is formed in steps j to m is taken out from the sputtering apparatus, and the intermediate layer 16 is formed. The intermediate layer 16 is formed by the following procedure. First, an ultraviolet curable resin is applied to the surface of the fourth dielectric layer 17 by, for example, spin coating. Next, the guide groove side of the polycarbonate substrate on which the guide groove is formed is brought into close contact with the ultraviolet curable resin. In that state, ultraviolet rays are irradiated to cure the resin, and then the polycarbonate substrate on which the guide groove is formed is peeled off. Thereby, the guide groove is transferred to the ultraviolet curable resin, and the intermediate layer 16 having the guide groove as shown is formed. Alternatively, the intermediate layer 16
May be formed by forming a layer for protecting the fourth dielectric layer 17 with an ultraviolet curable resin and forming a layer having a guide groove thereon. In that case, the resulting intermediate layer is 2
It is a layered structure.

The substrate 101 on which the intermediate layer 16 has been formed is placed again in the sputtering apparatus to form the first information layer 21 on the surface of the intermediate layer 16. The step of forming the first information layer 21 corresponds to steps n to r.

Step n is a step of forming the third dielectric layer 15 on the surface of the intermediate layer 16 having the guide groove. Process n
In the case of using a high frequency power source, TiO ₂ or Cr ₂
Ar using a sputtering target composed of O ₃
Sputtering is performed in a gas atmosphere or a mixed gas atmosphere of Ar gas and O ₂ gas. Alternatively, step n
In, the sputtering may be performed in an Ar gas atmosphere using a sputtering target made of a mixture of ZrO ₂ and Cr ₂ O ₃ . Alternatively, step n
In the above, reactive sputtering may be performed in a mixed gas atmosphere of Ar gas and O ₂ gas using a sputtering target made of Ti or Cr.

Next, step o is carried out to form the first reflective layer 14 on the surface of the third dielectric layer 15. In step o, sputtering is carried out in an Ar gas atmosphere using a DC power supply and a sputtering target of an alloy containing Ag. The step n may be performed again before the step p is performed. This is because the first reflective layer 14 is Ag
In the case where an element that reacts with S is included, the step corresponds to the step of forming a layer that prevents the reaction.

Next, step p is carried out to carry out the first reflection layer 1
A second dielectric layer 6 is deposited on the surface of 4. Step p is performed in the same manner as step k.

Next, step q is carried out to form the first recording layer 13 on the surface of the second dielectric layer 6. In step q, a DC power supply is used, and Ge-Sb-Te, Ge-S is used.
n-Sb-Te, Ge-Bi-Te, Ge-Sn-Bi
-Te, Ge-Sb-Bi-Te, and Ge-Sn-
Sputtering is performed in an Ar gas atmosphere or a mixed gas atmosphere of Ar gas and N ₂ gas using a sputtering target containing any one material selected from Sb-Bi-Te.

Next, step r is carried out to carry out the first recording layer 1
The first dielectric layer 2 is deposited on the surface of 3. Step r is performed in the same manner as step m. Thus, steps n to r are sequentially performed to form the first information layer 21.

The substrate 101 on which the first information layer 21 has been formed is taken out from the sputtering apparatus. Then, an ultraviolet curable resin is applied to the surface of the first dielectric layer 2 by, for example, a spin coating method. To the applied UV curable resin,
The dummy substrate 110 is brought into close contact with the dummy substrate 1 so that ultraviolet rays can be emitted from the dummy substrate 1.
Irradiation is performed from the 10 side to cure the resin, and the bonding step is completed. Also in the method of manufacturing the information recording medium of the fifth embodiment, the step of attaching the dummy substrate 110 can be omitted in the same manner as the method of manufacturing the information recording medium of the fourth embodiment.

After the bonding process is completed, the initialization process of the second information layer 22 and the first information layer 21 is carried out if necessary. The initialization step may be performed on the second information layer 22 before or after forming the intermediate layer, and may be performed on the first information layer 21 before or after the step of attaching the dummy substrate 110. The method of performing the initialization step is as described in relation to the first embodiment.

(Embodiment 6) As Embodiment 6 of the present invention, still another example of an information recording medium for recording and reproducing information using laser light will be described. FIG. 6 shows a partial cross section of the optical information recording medium.

The information recording medium 30 shown in FIG. 6 has a first dielectric layer 102, a first interface layer 3, a recording layer 4, a second interface layer 5, and a second interface layer on one surface of a substrate 1. Dielectric layer 10
6, the light absorption correction layer 7, and the reflection layer 8 are formed in this order, and the dummy substrate 10 is further adhered by the adhesive layer 9. In the information recording medium 30 shown in FIG. 6, the first and second interface layers 3 and 5 are made of Zr-Zn-S-.
It is an O-based material layer. 6, the same reference numerals as those used in FIG. 1 represent the same elements and are formed by the materials and the methods described with reference to FIG. Therefore, detailed description of the elements already described with reference to FIG. 1 will be omitted.

The information recording medium of this embodiment corresponds to a structure in which the first and second dielectric layers 102 and 106 are made of ZnS-20 mol% SiO ₂ used in the conventional information recording medium. In such a configuration, Zr
The —Zn—S—O-based material layer includes the first and second interface layers 3
And 5 can be used. First and second interface layer 3
The preferred materials for and 5 are the same as those for the first and second dielectric layers 2 and 6 of the first embodiment. Therefore, detailed description thereof will be omitted. The thickness of the first and second interface layers 3 and 5 is preferably 1 to 10 nm, and more preferably about 2 to 7 nm so as not to affect the recording / erasing performance. Zr-
The interface layer, which is a Zn—S—O-based material layer, has a lower material cost, a smaller extinction coefficient (higher transparency), and a lower interface cost than a conventional interface layer made of a nitride containing Ge. It has an advantage that it has a high melting point and is thermally stable.

Next, the information recording medium 30 of the sixth embodiment.
A method of manufacturing the will be described. In the information recording medium 30, a step of forming the first dielectric layer 102 on the surface of the substrate 1 in which the guide groove is formed (step h), a step of forming the first interface layer 3 (step s), Second step of forming the recording layer 4 (step b)
The step of forming the interface layer 5 (step t), the step of forming the second dielectric layer 106 (step g), the step of forming the light absorption correction layer 7 (step d), and the reflection layer 8 It is manufactured by sequentially performing the step of forming a film (step e), further forming the adhesive layer 9 on the surface of the reflective layer 8, and adhering the dummy substrate 10. Step b,
d and e are as described in connection with the first embodiment, step g is as described in connection with the second embodiment, and step h is as described in connection with the third embodiment. Therefore, the description thereof is omitted here.

Step s is a step of forming the first interface layer 3 on the surface of the first dielectric layer 102. Step s is performed in the same manner as step a in the first embodiment. Step t is
It is a step of forming the second interface layer 5 on the surface of the recording layer 4. Step t is performed in the same manner as step c in the first embodiment.

As described above, with reference to FIGS. 1 to 6, an optical information recording medium for recording / reproducing with a laser beam has been described as an embodiment of the information recording medium of the present invention. The optical information recording medium of the present invention is not limited to these forms. The optical information recording medium of the present invention can take any form as long as the Zr—Zn—S—O-based material layer is provided as one of the constituent layers, preferably in contact with the recording layer. Further, the optical information recording medium of the present invention is suitable for recording at various wavelengths. Therefore, the optical information recording medium of the present invention has, for example, a wavelength of 630.
DVD-RAM for recording / reproducing with laser light up to 680 nm
Alternatively, it may be a DVD-R, a large-capacity optical disc that records and reproduces with a laser beam having a wavelength of 400 to 450 nm, or the like.

(Embodiment 7) As Embodiment 7 of the present invention, an example of an information recording medium for recording and reproducing information by applying electric energy will be shown. FIG. 7 shows a partial cross section of the information recording medium.

In FIG. 7, the lower electrode 2 is formed on the surface of the substrate 201.
02, the recording portion 203, and the upper electrode 204 are the memory 207 formed in this order. Recording unit 2 of memory 207
03 has a structure including a cylindrical recording layer 205 and a dielectric layer 206 surrounding the recording layer 205. Figure 1
Unlike the optical information recording medium described with reference to FIG. 6, in the memory 207 of this form, the recording layer 205 and the dielectric layer 206 are formed on the same surface, and they are not in a laminated relationship. However, in the memory 207, both the recording layer 205 and the dielectric layer 206 are included in the substrate 20.
Since they constitute a part of the laminated body including the first, lower and upper electrodes 202 and 204, they can be called “layers”. Therefore, the information recording medium of the present invention includes a recording layer and a dielectric layer on the same surface.

As the substrate 201, specifically, a semiconductor substrate such as a Si substrate, a polycarbonate substrate, or a Si substrate is used.
An insulating substrate such as an O ₂ substrate and an Al ₂ O ₃ substrate can be used as the substrate 201. The lower electrode 202 and the upper electrode 204 are formed of a suitable conductive material. The lower electrode 202 and the upper electrode 204 are, for example, Au, Ag,
It is formed by sputtering metals such as Pt, Al, Ti, W and Cr and mixtures thereof.

The recording layer 205 constituting the recording section 203 is
It is made of a material that undergoes a phase change by applying electric energy, and can also be called a phase change portion. The recording layer 205 is formed of a material that undergoes a phase change between a crystalline phase and an amorphous phase due to Joule heat generated by applying electric energy. Examples of the material of the recording layer 205 include Ge-Sb-Te and Ge-Sn-Sb-T.
e, Ge-Bi-Te, Ge-Sn-Bi-Te, Ge
-Sb-Bi-Te and Ge-Sn-Sb-Bi-T
An e-based material is used, and more specifically, GeTe-Sb
₂ Te ₃ based or GeTe—Bi ₂ Te ₃ based materials are used.

Dielectric layer 206 constituting recording section 203
Has a function of preventing a current flowing in the recording layer 205 from escaping to the peripheral portion by applying a voltage between the upper electrode 204 and the lower electrode 202, and electrically and thermally insulating the recording layer 205. Have. Therefore, the dielectric layer 206 can also be referred to as a heat insulating portion. Dielectric layer 2
06 is a Zr-Zn-S-O-based material layer, and specifically, is substantially made of a material represented by the above formula (1), (11), (2), (21) or (22). Is a layer. Z
The r-Zn-S-O-based material layer is preferably used because it has a high melting point, atoms in the material layer do not easily diffuse even when heated, and the thermal conductivity is low.

This memory 207 will be further described together with its operating method in the embodiments described later.

[0160]

EXAMPLES Example 1 In Example 1, as a preliminary test until completion of the present invention, FIG.
The information recording medium having the same structure as that of the information recording medium 25 described above with reference to the above, and the first dielectric layer and the second dielectric layer are made of materials having the same composition, The materials were prepared by various changes as shown in Table 1.

Hereinafter, a method of manufacturing the information recording medium will be described. For ease of understanding, the same reference numerals as those of the constituent elements of the information recording medium 25 of FIG. It is to be noted that the same numbers are used for the information recording mediums of the examples described later as well as the components of the corresponding information recording mediums).

First, as the substrate 1, a guide groove having a depth of 56 nm and a track pitch (center-to-center distance between groove surface and land surface in a plane parallel to the main surface of the substrate) of 0.615 μm was previously provided on one surface. , Diameter 120 mm,
A circular polycarbonate substrate having a thickness of 0.6 mm was prepared.

On this substrate 1, (ZnS) ₈₀ (SiO 2
₂ ) ₂₀ (mol%) of the first dielectric layer 2 having a thickness of 150 nm, Ge ₂₇ Sn ₈ Sb ₁₂ Te ₅₃ (atomic%) of the recording layer 4 having a thickness of 9 nm, and (ZnS) ₈₀ ( SiO ₂ ) ₂₀ (m
ol%) second dielectric layer 6 with a thickness of 50 nm and Ge
The light absorption correction layer 7 of ₈₀ Cr ₂₀ (atomic%) has a thickness of 40 nm, and the reflection layer 8 of Ag-Pd-Cu has a thickness of 80 nm.
Films were sequentially formed by the sputtering method as follows.

In the step of forming the first dielectric layer 2, a sputtering target (diameter 100 mm, thickness 6 mm) having a composition of (ZnS) ₈₀ (SiO ₂ ) ₂₀ (mol%) was attached to the film forming apparatus. With a power of 400W,
High frequency sputtering was performed by introducing a mixed gas of Ar gas (97%) and O ₂ gas (3%). The pressure during sputtering was about 0.13 Pa.

In the step of forming the recording layer 4, Ge is used.
Te-Sb ₂ Te ₃ pseudo-binary system a portion of the Ge composition consisting Ge-Sn-Sb-Te-based material obtained by substituting Sn sputtering target (diameter 100 mm, thickness 6mm) mounting the film forming apparatus, power 100W Then, Ar gas (97
%) And N ₂ gas (3%) were introduced to perform DC sputtering. The pressure during sputtering is about 0.13
It was Pa.

The step of forming the second dielectric layer 6 includes the first step.
Of the first dielectric layer 2 except that the layer thickness is changed so that the dielectric layer 2 and the second dielectric layer 6 have substantially the same composition. It was carried out.

In the step of forming the light absorption correction layer 7, a sputtering target (diameter: 100 mm, thickness: 6) made of a material having a composition of Ge ₈₀ Cr ₂₀ (atomic%).
(mm) is attached to the film forming apparatus, and the power is 300 W, and Ar is
Gas (100%) was introduced to perform DC sputtering. The pressure during sputtering was about 0.4 Pa.

In the step of forming the reflective layer 8, Ag is used.
A sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of —Pd—Cu was attached to a film forming apparatus, and a power of 200 W and an Ar gas (100
%) Was introduced and DC sputtering was performed. The pressure during sputtering was about 0.4 Pa.

As described above, the first dielectric layer 2, the recording layer 4, the second dielectric layer 6, and the light absorption correction layer 7 are formed on the substrate 1.
The reflective layer 8 and the reflective layer 8 are sequentially formed to form a laminated body, and then an ultraviolet curable resin is applied onto the reflective layer 8, and a diameter 120 is formed as a dummy substrate 10 on the applied ultraviolet curable resin.
A circular polycarbonate substrate having a thickness of 0.6 mm and a thickness of 0.6 mm was closely attached. Then, the resin was cured by irradiating ultraviolet rays from the dummy substrate 10 side. As a result, the adhesive layer 9 made of the cured resin was formed to a thickness of 30 μm, and the dummy substrate 10 was attached to the laminated body via the adhesive layer 9.

After the bonding, the wavelength 8 is used as an initialization process.
Using a 10 nm semiconductor laser, the recording layer 4 of the information recording medium 25 was crystallized over almost the entire area within an annular region having a radius of 22 to 60 mm. As a result, the initialization process was completed, and the production of the information recording medium 25 of sample number 1-1 was completed.

Further, it has the same structure as the information recording medium 25 of sample number 1-1, except that the materials of the first dielectric layer 2 and the second dielectric layer 6 are the materials shown in Table 1. , Information recording medium 2 of sample numbers 1-2 to 1-12
5 was produced. The information recording medium 25 is the same as the information recording medium 25 of the sample number 1-1, except that the film forming steps of the first dielectric layer and the second dielectric layer are changed. It was made.

In order to manufacture the information recording medium 25 of sample numbers 1-2 to 1-12, in the film forming process of the first dielectric layer 2 and the second dielectric layer 6, SiO ₂ , Zn
S, (ZnSe) ₈₀ (SiO ₂ ) ₂₀ (mol%), Zn
Se, ZrO ₂ , (ZrO ₂ ) ₈₀ (SiO ₂ ) ₂₀ (mol
%), ZrSiO ₄ , Ge ₉₀ Cr ₁₀ (atomic%), (Bi ₂
Sputtering target made of a material having a composition of O ₃ ) ₈₀ (SiO ₂ ) ₂₀ (mol%), TeO ₂ and (TeO ₂ ) ₈₀ (SiO ₂ ) ₂₀ (mol%) (all having a diameter of 100 mm and a thickness of 6 mm) Were used respectively.

The power is adjusted according to the melting point of the material used as the sputtering target. Specifically, the sample number 1-2 is 1 kW, and the sample numbers 1-3 to 1-5 are sample number 1 Same as -1, 400W, 5 for sample numbers 1-6 to 1-8
00W, 300W for sample numbers 1-9, and 200W for sample numbers 1-10 to 1-12. The pressure during sputtering was about 1.
Although it was set to 33 Pa, it was set to about 0.13 Pa in other samples as in the case of sample number 1-1. Sample numbers 1-2 and 1-10-1 were used for the gas introduced into the film forming apparatus.
For -12, a mixed gas of Ar gas (97%) and O ₂ gas (3%) was used similarly to sample number 1-1, and for sample numbers 1-3 to 1-8, Ar gas (100%) was used.
%) Was used, and for sample numbers 1-9, a mixed gas of Ar gas (60%) and N ₂ gas (40%) was used.

In the step of forming the first and second dielectric layers, in the case of the information recording medium of sample number 1-9, N ₂ in the mixed gas was mixed with Ge and Cr sputtered from the sputtering target. Reacts with Ge-Cr-N
Of the dielectric layer was formed. In the case of other samples, it was believed that the deposited dielectric layer would have substantially the same composition as the sputtering target used.

In addition, for comparison, as shown in FIG. 9, between the first dielectric layer 102 and the recording layer 4 and the second dielectric layer 102.
Between the dielectric layer 106 and the recording layer 4 of the first interfacial layer 1
03 and the second interface layer 105, an information recording medium 31 having a conventional structure was produced. First interface layer 10
3 and the second interface layer 105 are both Ge-Cr-N
And has a thickness of 5 nm.

The information recording medium 31 of this conventional structure is the first
The information recording medium was manufactured under the same conditions as those of the information recording medium of Sample No. 1-1 except that the interface layer 103 and the second interface layer 105 were formed. In the film forming process of the first interface layer 103, a sputtering target (diameter 100 m) made of a material having a composition of Ge ₉₀ Cr ₁₀ (atomic%) is used.
m, thickness 6 mm) is attached to the film forming apparatus and the power is 300
With W, a mixed gas of Ar gas (60%) and N ₂ gas (40%) was introduced, and high frequency sputtering was performed under a pressure of about 1.33 Pa. As a result, N ₂ in the mixed gas reacts with Ge and Cr sputtered from the sputtering target to cause the Ge-Cr-N first interface layer 103.
Was formed. The film forming process of the second interface layer 105 was also performed under the same conditions.

Sample No. 1 obtained as described above
With respect to the information recording media 25 of -1 to 1-12 and the information recording medium 31 of the comparative example (conventional structure), the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated. As described later, the adhesiveness was evaluated by the presence or absence of peeling, and the rewriting performance was evaluated by the number of repetitions. These results are shown in Table 1 together with the peak power (Pp) obtained at the time of evaluating the rewriting performance. Note that neither the information recording medium 25 of sample numbers 1-1 to 1-12 nor the information recording medium 31 of the comparative example belong to the scope of the present invention.

The adhesion of the dielectric layer on the information recording medium 25 was evaluated based on the presence or absence of peeling under high temperature and high humidity conditions. Specifically, the information recording medium 25 after the initialization process
In a high temperature and high humidity tank with a temperature of 90 ° C and a relative humidity of 80%.
After leaving for a while, between the recording layer and the dielectric layer in contact with it,
More specifically, it was visually examined using an optical microscope whether peeling occurred between the recording layer 4 and at least one of the first dielectric layer 2 and the second dielectric layer 6. of course,
Those without peeling have a high evaluation of adhesion, and those with peeling have a low evaluation of adhesion.

Further, the repetitive rewriting performance of the information recording medium 25 was evaluated using the number of times of repetition as an index, and the number of times of repetition was determined under the following conditions.

In order to record information on the information recording medium 25, a spindle motor for rotating the information recording medium 25, an optical head provided with a semiconductor laser for emitting the laser beam 12, and recording the laser beam 12 on the information recording medium 25. An information recording system having a general configuration including an objective lens for focusing light on the layer 4 was used. In the evaluation of the information recording medium 25, a semiconductor laser with a wavelength of 660 nm and a numerical aperture of 0.6
Using the objective lens of, the recording corresponding to the capacity of 4.7 GB was performed. The linear velocity for rotating the information recording medium 25 is 8.2 m.
/ Sec. A time interval analyzer was used for measuring the jitter value when obtaining the average jitter value described later.

First, the peak power (Pp) and the bias power (Pb) were set in the following procedure in order to determine the measurement conditions when determining the number of repetitions. Using the system described above, the laser light 12 is power-modulated between the peak power (mW) of the high power level and the bias power (mW) of the low power level, and the information recording medium 25.
The mark length is 0.42 μm (3T) ~
A random signal of 1.96 μm (14T) was recorded on the same groove surface of the recording layer 4 (by groove recording) 10 times. Then, the jitter value between the front end and the jitter value between the rear ends were measured, and an average jitter value was obtained as an average value thereof. When the average jitter value is measured under each recording condition in which the bias power is fixed to a fixed value and the peak power is variously changed, and the peak power is gradually increased until the average jitter value of the random signal reaches 13%. The power of 1.3 times the peak power of 1 was temporarily determined as Pp1. Next, the average jitter value was measured under each recording condition in which the peak power was fixed to Pp1 and the bias power was variously changed. The upper limit value of the bias power when the average jitter value of the random signal was 13% or less And the average value of the lower limit values was set to Pb. Then, when the bias power is fixed to Pb and the average jitter value is measured under each recording condition in which the peak power is variously changed, the peak power is gradually increased, and when the average jitter value of the random signal reaches 13%. The peak power of 1.3 times was set to Pp. When recording under the conditions of Pp and Pb set in this way,
For example, in repeated recording 10 times, an average jitter value of 8 to 9% was obtained. Considering the laser power upper limit of the system, it is desirable to satisfy Pp ≦ 14 mW and Pb ≦ 8 mW.

The number of times of repetition, which is an index of repetitive rewriting performance, was determined based on the average jitter value in this embodiment. The laser light is power-modulated by Pp and Pb set as described above, and is irradiated toward the information recording medium 25, and the mark length is 0.42 μm (3T) to 1.96 μm (1
An average jitter value was measured after continuously recording a random signal of 4T) on the same groove surface by a predetermined number of times (by groove recording). The number of repetitions is 1, 2, 3,
5, 10, 100, 200 and 500 times, 1000-
In the range of 10,000 times, every 1000 times and 200
In the range of 00 to 100,000 times, it was set to every 10,000 times. When the average jitter value reached 13%, it was judged as the limit of repeated rewriting, and the repeated rewriting performance was evaluated by the number of times of repetition at this time. Of course, the larger the number of repetitions, the higher the repetitive rewriting performance. When the information recording medium is used as an external memory of a computer, the number of repetitions is preferably 100,000 or more,
For image / audio recorder applications, 10,000 times or more is preferable.

[0183]

[Table 1]

As shown in Table 1, sample numbers 1-1 to 1-1
Among the information recording media of Nos. 1-8, there is no peeling (high adhesion) (that is, sample numbers 1-1 and 1).
-3 to 1-5), the number of repetitions is 100,000
The number of repetitions for the information recording mediums having peeling (low adhesion) (i.e., sample numbers 1-2 and 1-6 to 1-8), while the total number of times is less than (repetitive rewriting performance is low). Was more than 100,000 times (repetitive rewriting performance was high).

Sample numbers 1-9 and 1-10
With respect to the information recording medium (1), sufficient recording marks could not be formed at a peak power of 14 mW or less, and thus the recording sensitivity was low. The reason for this was that the thermal conductivity of the material of the dielectric layer in these samples was expected to be higher than that of other samples.

Sample numbers 1-11 and 1-1
The information recording medium No. 2 could not be rewritten and the material of the dielectric layer was melted and mixed with the recording layer during recording. It is considered that this is because the melting point of the material of the dielectric layer in these samples is lower than that of other materials.

On the other hand, in the information recording medium of the comparative example of the conventional structure (which has the interface layer), there is no peeling and the number of repetitions is 100,000 times or more, and the adhesion and the rewriting performance are good. Both were expensive.

Further, comparing the information recording media of sample numbers 1-1 to 1-8 with respect to Pp, (ZnS)
Information recording media using ₈₀ (SiO ₂ ) ₂₀ , (ZnSe) ₈₀ (SiO ₂ ) ₂₀ and ZrSiO ₄ as the material of the dielectric layer (that is, sample numbers 1-1, 1-4 and 1-8, respectively). Had a low Pp and therefore high recording sensitivity. (ZnS) ₈₀ (SiO ₂ ) ₂₀ and (ZnSe) ₈₀ (S
information recording media using iO ₂ ) ₂₀ as the material of the dielectric layers (ie, sample numbers 1-1 and 1-
Comparing 4), the one using (ZnS) ₈₀ (SiO ₂ ) ₂₀ was superior in repetitive rewriting performance.

According to the results of the preliminary test as described above, as the material of the dielectric layer in contact with the recording layer, oxide, nitride,
Selenide, sulfide, or any of these and SiO
Sample number 1-1 using a mixture of ₂ and
Among the information recording media of Nos. 1 to 12, none of them simultaneously satisfied high adhesion and high repetitive rewriting performance. However, it was revealed in the present embodiment, the material comprising a ZrO ₂ or ZrO ₂ and SiO ₂
Information recording medium of the material used in the material of the dielectric layer comprising (sample number 1-6～1-8) has excellent repeated rewriting performance, in particular, use a material consisting of ZrSiO ₄ in the material of the dielectric layer Information recording medium (Sample No. 1-8)
Was excellent in repetitive rewriting performance and had high recording sensitivity. Further, the information recording media (Sample Nos. 1-1, 1-3 to 1-5) using the material containing ZnS or ZnSe as the material of the dielectric layer have excellent adhesion to the recording layer,
In addition, the information recording mediums (Sample Nos. 1-1 and 1-3) that have a high recording sensitivity and that use a material containing ZnS as a material for the dielectric layer are those that use a material containing ZnSe (Sample No. 1). -4 and 1-5), it was also found to be superior in repeated rewriting performance.

From the results of this example as a preliminary test, Z
Mixture of rO ₂ and ZnS, ZrO ₂ , SiO ₂ and ZnS
It was expected that high adhesion and high repetitive rewriting performance could be achieved at the same time by using a mixture thereof with or a mixture of ZrSiO ₄ and ZnS as the dielectric layer material.

Example 2 In Example 2, Zr—Zn mixed with ZrO ₂ and ZnS was prepared for the purpose of simultaneously achieving high adhesion and high rewritability.
The —S—O based material layer was used as the dielectric layer.

Also in this embodiment, as in the first embodiment,
An information recording medium 25 (FIG. 1) in which the first dielectric layer and the second dielectric layer are made of materials having the same composition as each other is prepared by variously changing the materials of these dielectric layers as shown in Table 2. did. In Example 2, (ZrO ₂ ) _X (ZnS)
_In order to investigate the composition range suitable for use in the dielectric layer for the material of the system described as _100-X (mol%),
And the material of the second dielectric layer is Zr as shown in Table 2.
Information recording media were produced by changing the content X (mol%) of O ₂ variously. In addition, not "Zn-S" but "ZnS"
In the case of notation, it indicates a composition in which (the number of S atoms) / (the number of Zn atoms) is approximately 1 (the same applies to the following examples unless otherwise specified).

The information recording medium of this example has the same structure as the information recording medium 25 of Example 1 except that the materials of the first and second dielectric layers are the materials shown in Table 2. It was produced in the same manner as this except that the film forming steps of the first and second dielectric layers were changed. Sample numbers 2-1 to 2
In order to manufacture the information recording medium of −9, in the film forming process of the first dielectric layer and the second dielectric layer, a sputtering target (diameter 100 mm, thickness 100 mm, thickness 6 mm) was used. Further, in the film forming process of the first dielectric layer and the second dielectric layer, the power was 400 W, the pressure was about 0.13 Pa, and the gas introduced into the film forming apparatus was Ar for all samples. Gas (100%) was used.

The dielectric layer formed by the sputtering method was considered to have substantially the same composition as the sputtering target used. The same applies to the examples described below unless otherwise specified.

Sample No. 2 obtained as described above
Regarding the information recording media of -1 to 2-9, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated in the same manner as in Example 1. These results are used as the peak power (Pp) obtained when the rewriting performance is evaluated.
It is shown together with Table 2. Table 2 shows the results of the same evaluations of the information recording media of Sample Nos. 1-1, 1-3 and 1-6 produced in Example 1. Further, for comparison, the results of the similar evaluation of the information recording medium 31 having the conventional structure shown in FIG. 10 and manufactured in Example 1 are also shown in Table 2 (see Tables 3 to 8 and 10 for Examples described later). The same shall apply).

[0196]

[Table 2]

As shown in Table 2, Zn in the dielectric layer material
Comparing with the information recording media of sample numbers 2-2 and 1-1 (without an interface layer) having the same S and oxide contents (they have the same structure), sample number 1-1
In the information recording medium of No. 2, the number of repetitions is 1000, while in the information recording medium of Sample No. 2-2, it is 400.
A result of 0 times was obtained. Conventional (ZnS) ₈₀ (Si
From the result that a larger number of repetitions can be obtained with the material of (ZnS) ₈₀ (ZrO ₂ ) ₂₀ than the material of O ₂ ) ₂₀ ,
It has been found that the ZnS-ZrO ₂ -based material is more suitable as the dielectric layer material than the ZnS-SiO ₂ -based material.

Further, (ZrO ₂ ) _X (ZnS) _100-X (m
information recording medium (sample numbers 1-3, and 2-1 to ₂ ) in which a ZrO ₂ —ZnS-based material having a composition range satisfying X ≦ 80 is used as the material of the dielectric layer.
In -8), peeling did not occur, and thus high adhesion could be secured. Further, in the above formula, Z in the composition range of 50 ≦ X is
Information recording medium using sample of rO ₂ —ZnS system as material of dielectric layer (sample numbers 2-5 to 2-9 and 1-6)
In, the number of repetitions of 10,000 or more was obtained. Therefore, from the results of this example, X in the above formula is 50
It was confirmed that a material having a composition range satisfying ≦ X ≦ 80 was preferable. Further, in an information recording medium using a ZrO ₂ —ZnS-based material having this composition range as the material for the dielectric layer,
From Table 2, the peak power Pp was less than 14 mW.
As described above, when the Zr—Zn—S—O-based material layer according to the present invention is used for the dielectric layer, in the information recording medium 25 shown in FIG. 1 having no interface layer, high adhesion and high repetition rate are obtained. Rewriting performance is obtained, and Pp <1
4mW was also obtained.

Example 3 In Example 3, ZrO ₂ − was used for the purpose of realizing an information recording medium with high recording sensitivity.
An information recording medium was prepared using a mixture of ZnS-based material and SiO ₂ as a material for the dielectric layer. Also in this embodiment, as in the first embodiment, the information recording medium 25 made of a material in which the first dielectric layer and the second dielectric layer have the same composition as each other is shown in Table 3. As shown in FIG. In Example 3, (ZrO ₂ )
_Y (SiO ₂ ) _Z (ZnS) _100-Y-Z (mol%) (where (number of S atoms) / (number of Zn atoms) is approximately 1) In order to investigate the composition range suitable for use in the body layer, the materials of the first and second dielectric layers were set to ZrO ₂ and Si as shown in Table 3.
Information recording media were produced by varying the O ₂ content Y and Z (mol%) variously. Here, 4 where Y + Z = 50
The types of compositions and the seven types of compositions with Y + Z = 80 were examined.

The information recording medium of Example 1 is also the same as Example 2, except that the materials for the first and second dielectric layers are the materials shown in Table 3. A structure similar to that was used, and was manufactured under the same conditions as those except that the film forming steps of the first and second dielectric layers were changed. In order to manufacture the information recording media of Sample Nos. 3-1 to 3-11, in the film forming process of the first dielectric layer and the second dielectric layer, it is made of a material having a predetermined composition shown in Table 3. Sputtering target (diameter 100 mm, thickness 6
mm) were used respectively. In addition, the film forming steps of the first dielectric layer and the second dielectric layer were performed under the same conditions as in Example 2.

Sample No. 3 obtained as described above
Regarding the information recording media of -1 to 3-11, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated in the same manner as in Example 1. These results are used as the peak power (Pp) obtained when the rewriting performance is evaluated.
Are shown in Table 3.

[0202]

[Table 3]

As shown in Table 3, (ZrO ₂ ) _Y (SiO _{2
2) Z (ZnS) 100-} Y-Z ( labeled by a formula: mol%), Y + Z = ZrO 2 composition ranges satisfying 50 -SiO ₂
Among the information recording media (Sample Nos. 3-1 to 3-4) using the ZnS-based material as the material of the dielectric layer, 20 ≦ Y ≦
In the composition range of 40 and 10 ≦ Z ≦ 30 (sample numbers 3-2 to 3-4), peeling did not occur, the number of repetitions was 20000 times, and the peak power Pp was 11.8 mW or less.
Good results were obtained. Sample number 2 in which the content rates of ZnS in the information recording medium and the dielectric layer material are equal
In the information recording medium of -5 (see Table 2), the number of repetitions was 10,000 and Pp was 12.6 mW.
Therefore, from this comparison, ZrO ₂ —ZnS-based material is
It was found that by using a material mixed with O ₂ as the material of the dielectric layer, high recording sensitivity can be achieved and repetitive rewriting performance can be improved.

An information recording medium (Sample No. 3-5) using a ZrO ₂ --SiO ₂ --ZnS based material represented by the above formula and having a composition range satisfying Y + Z = 80 as a material for the dielectric layer.
To 3-11), 30 ≦ Y ≦ 70 and 10 ≦ Z ≦ 5
0 composition range (Sample Nos. 3-7 to 3-11)
No peeling occurred, and good results of 100,000 or more repetitions and a peak power Pp of 12.9 mW or less were obtained. In the sample number 2-8 information recording medium (see Table 2) in which the content of ZnS in the dielectric layer material is equal to those of the information recording medium, the number of repetitions is 700.
00 times, Pp was 13.6 mW. Therefore, also from this comparison, it was found that by mixing SiO ₂ with the ZrO ₂ —ZnS-based material, high recording sensitivity can be achieved and repetitive rewriting performance can be improved.

Therefore, from the results of this example, it is confirmed that the material of the dielectric layer is preferably a material having a composition range in which Y and Z in the above formula satisfy 20 ≦ Y ≦ 70 and 10 ≦ Z ≦ 50. Was done.

(Example 4) In Example 4, Zr- mixed ZrSiO ₄ and ZnS was used for the purpose of simultaneously achieving high adhesion and high rewritability.
A Zn-S-O based material layer was used as the dielectric layer. Also in this embodiment, as in the first embodiment, the information recording medium 25 (FIG. 1) in which the first dielectric layer 2 and the second dielectric layer 6 are made of materials having the same composition as each other is used. Various materials were prepared as shown in Table 4 to fabricate. In Example 4, (ZrSiO ₄ ) _A (ZnS) _100-A (mol%)
In order to investigate the composition range suitable for use in the dielectric layer for the material of the system represented by (wherein (the number of S atoms) / (the number of Zn atoms) is approximately 1), the first and Information recording media were prepared by changing the ZrSiO ₄ content A (mol%) of the material of the second dielectric layer as shown in Table 4.

The information recording medium of this example is also the same as that of example 2 except that the materials of the first and second dielectric layers are the materials shown in Table 4. A structure similar to that was used, and was manufactured under the same conditions as those except that the film forming steps of the first and second dielectric layers were changed. In order to manufacture the information recording media of Sample Nos. 4-1 to 4-9, in the film forming process of the first dielectric layer and the second dielectric layer, it is made of a material having a predetermined composition shown in Table 4. Sputtering target (diameter 100 mm, thickness 6 m
m) were used respectively. In addition, the film forming steps of the first dielectric layer and the second dielectric layer were performed under the same conditions as in Example 2.

Sample No. 4 obtained as described above
Regarding the information recording media of -1 to 4-9, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated in the same manner as in Example 1. These results are used as the peak power (Pp) obtained when the rewriting performance is evaluated.
Are shown in Table 4. Table 4 shows the results of the same evaluations of the information recording media of sample numbers 1-3 and 1-8 produced in Example 1.

[0209]

[Table 4]

As shown in Table 4, (ZrSiO ₄ ) _A (Z
nS) _100-A (mol%), and A ≦ 67
An information recording medium using a ZrSiO ₄ —ZnS-based material having a composition range that satisfies
3 and 4-1 to 4-8), peeling did not occur,
Therefore, high adhesion could be secured. Also, in the above formula, 33
An information recording medium using a ZrO ₂ —ZnS-based material having a composition range of ≦ A as a material for a dielectric layer (sample numbers 4-5 to 4-4).
-9 and 1-8), the number of repetitions is 1000
Reached 00 times. Therefore, in the composition range of 33 ≦ A ≦ 67 (Sample Nos. 4-5 to 4-8), peeling did not occur, and the number of repetitions of 100,000 times was obtained. Also,
In this composition range, a peak power Pp almost equal to that of the conventional structure was obtained. Therefore, it was confirmed that as the material of the dielectric layer, a material having a composition range in which A in the above formula satisfies 33 ≦ A ≦ 67 is preferable. As described above, when the Zr—Zn—S—O-based material layer according to the present invention is used as the dielectric layer, the information recording medium 25 shown in FIG. Higher performance was obtained.

(Example 5) In Example 5, Zr-Zn-
Zn existing in the form of Zn-S in the S-O material layer
The range of the preferable composition ratio of S and S was investigated. Also in this embodiment, as in the first embodiment, the first dielectric layer and the second dielectric layer
The information recording medium 25, in which the dielectric layers of No. 1 and No. 3 were made of materials having the same composition, was produced by variously changing the materials of the dielectric layers as shown in Table 5. In Example 5, (ZrS
_{iO 4) A (Zn-S} ) 100-A ( in order to examine the composition range suitable for use in the dielectric layer for mol%) and the material of the system, denoted, the first and second dielectric layers Material
As shown in Table 5, in the range of 33 ≦ A ≦ 67,
Information recording media were manufactured by variously changing (number of S atoms) / (number of Zn atoms). Here, A = 33, 43, 54
For each of the conditions 67 and 67, (the number of S atoms) / (the number of Zn atoms) = 0.5, 1.5, 2, and 2.5 1
Six compositions were investigated.

Like the information recording medium of Example 2, the information recording medium of Example 1 also includes the information recording medium 25 of Example 1 except that the materials for the first and second dielectric layers are the materials shown in Table 5. A structure similar to that was used, and was manufactured under the same conditions as those except that the film forming steps of the first and second dielectric layers were changed. In order to manufacture the information recording media of Sample Nos. 5-1 to 5-16, in the film forming process of the first dielectric layer and the second dielectric layer, the material having the predetermined composition shown in Table 5 is used. Sputtering target (diameter 100 mm, thickness 6
mm) were used respectively. In addition, the film forming steps of the first dielectric layer and the second dielectric layer were performed under the same conditions as in Example 2.

Sample No. 5 obtained as described above
Regarding the information recording media of -1 to 5-16, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated in the same manner as in Example 1. These results are used as the peak power (Pp) obtained when the rewriting performance is evaluated.
It is shown in Table 5 together with. Table 5 shows the results of the same evaluations of the information recording media of sample numbers 4-5 to 4-8 produced in Example 4. In the following, (number of S atoms)
/ (Number of Zn atoms) is also simply referred to as S / Zn.

[0214]

[Table 5]

As shown in Table 5, (ZrSiO_Four)_A(Z
n-S)_100−AIt is expressed by the formula (mol%) (where
33 ≦ A ≦ 67) and S / Zn = 0.5 are satisfied (ZrS
iO _Four)-(Zn-S) -based material is used as the material of the dielectric layer
All the information recording media (sample numbers 5-1 and 5-
Peeling occurred at 5, 5-9 and 5-13). On the other hand,
S / Zn = 1 to 2.5 (ZrSiO_Four)-(Zn
-S) Other information recording using the material of the dielectric layer as the material
Medium (4-5 to 4-8, 5-2 to 5-4, 5-6 to 5-
8, 5-10-5-12 and 5-14-5-16)
No peeling occurred.

The adhesion evaluation test is based on the presence / absence of peeling when left for 100 hours under predetermined conditions.
When left standing at 80 ° C and 80% relative humidity), S /
The larger the Zn, the longer the time until peeling occurred. Specifically, if S / Zn = 1, 200 hours, S / Zn
300 hours for Zn = 1.5, 400 for S / Zn = 2
No peeling occurred for 500 hours at S / Zn = 2.5.

In addition, in the above formula, an information recording medium (sample number 5-4, which uses a (ZrSiO ₄ )-(Zn-S) -based material satisfying S / Zn = 2.5 as the material of the dielectric layer, 5
-8, 5-12 and 5-16), the number of repetitions is 1
It was less than 0000 times. On the other hand, S / Zn = 0.5-
Another information recording medium using a (ZrSiO ₄ )-(Zn-S) -based material of 2.0 as the material of the dielectric layer (4-5 to
4-8, 5-1-5-3, 5-5-5-7, 5-9-5
-11 and 5-13 to 5-15), a repetition number of 10,000 or more was obtained.

Further, all information recording media (sample number 4
In -5 to 4-8 and 5-1 to 5-16), a peak power Pp almost equal to that of the conventional configuration was obtained.
In the above formula, when A is the same, the larger S / Zn is,
The peak power of the information recording medium was low and the recording sensitivity became high.

Therefore, in order to simultaneously realize high adhesion and high rewritability, the material of the dielectric layer is such that A in the above formula satisfies 33 ≦ A ≦ 67, and
It was confirmed that a material having a composition range satisfying 1 ≦ (number of S atoms) / (number of Zn atoms) ≦ 2 is preferable.

It should be noted that (ZrO ₂ ) _X (Zn-S)
_100-X (mol%) (in the formula, 50 ≦ X ≦ 80), a (ZrO ₂ ) — (Zn—S) -based material, and (ZrO ₂ ) _Y (SiO ₂ ) _Z (Zn— S) _100-Y-Z (m
ol%) (wherein 50 ≦ Y + Z ≦ 80, 20 ≦ Y ≦ 7
0,10 ≦ Z ≦ 50) (ZrO ₂ ) −
Similarly, for the (SiO ₂ )-(Zn-S) -based material, it was found that it is preferable that 1 ≦ (the number of S atoms) / (the number of Zn atoms) ≦ 2.

Example 6 In Example 6, the second embodiment will be described.
2 has a structure similar to that of the information recording medium 26 described above with reference to FIG. 2, and the first dielectric layer and the second dielectric layer are made of materials having different compositions, and the second dielectric layer An information recording medium having a second interface layer between the layer and the recording layer was produced.

The information recording medium 26 of this example was manufactured as follows. First, as the substrate 1, a depth of 56 nm, a track pitch (center-to-center distance between groove surface and land surface in a plane parallel to the main surface of the substrate) 0.615 μm
120m diameter with a guide groove on one side
A circular polycarbonate substrate having a m and a thickness of 0.6 mm was prepared.

On this substrate 1, (ZrSiO ₄ )
The first dielectric layer 2 made of ₅₄ (ZnS) ₄₆ (mol%)
Ge ₂₇ Sn ₈ Sb ₁₂ Te ₅₃ (atomic%) with a thickness of 0 nm
The recording layer 4 has a thickness of 9 nm, the second interface layer 105 of Ge—Cr—N has a thickness of 3 nm, and (ZnS) ₈₀ (Si
The second dielectric layer 106 of O ₂ ) ₂₀ (mol%) is set to 50 n.
Light absorption correction layer 7 of Ge ₈₀ Cr ₂₀ (atomic%) with a thickness of m
With a thickness of 40 nm and a reflective layer 8 of Ag-Pd-Cu 8
A film having a thickness of 0 nm was sequentially formed by a sputtering method. Here, the materials of the second interface layer 105 and the second dielectric layer 106 are the same as those in the conventional information recording medium 31 described above with reference to FIG.

The information recording medium 26 of this embodiment is different from the film forming process of the first dielectric layer 2 in that the film forming process of the recording layer 4 and the film forming process of the second dielectric layer 106 are performed. Second between
The information recording medium was prepared in the same manner as in the case of the information recording medium of Sample No. 1-1 of Example 1 except that the step of forming the interface layer 105 was added. In the film formation process of the first dielectric layer 2, a sputtering target (diameter 100 m) having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) was used.
m, thickness 6 mm) is attached to the film forming apparatus, and the power is 400
About 0.13P by introducing Ar gas (100%) with W
High-frequency sputtering was performed under the pressure of a. The step of forming the second interface layer 105 is performed in the same manner as the step of forming the second interface layer 105 in the method of manufacturing the information recording medium 31 having the conventional configuration of the comparative example described in Example 1. did. The step of forming the second dielectric layer 106 is performed by the information recording medium 2 of the sample number 1-1 described in the first embodiment.
This is the same as the step of forming the second dielectric film 6 in the manufacturing method of No. 5 and the same as the step of forming the second dielectric layer 106 in the manufacturing method of the information recording medium 31 having the conventional configuration.

Sample No. 6 obtained as described above
For the information recording medium 26 of No. -1, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated as in Example 1.
The evaluation was made in the same manner as described in 1. above, but in this example, the adhesion was evaluated by checking whether peeling occurred between the recording layer 4 and the first dielectric layer 2 in contact therewith. It was carried out by investigating. Further, the repetitive rewriting performance was evaluated by performing land recording as well as groove recording (that is, by land-groove recording) and examining the number of repetitions of each of groove recording and land recording. The results are shown in Table 6 together with the peak power (Pp) and the bias power (Pb) obtained when the rewriting performance was evaluated. in addition,
For comparison, Table 6 also shows the result of the similar evaluation of the information recording medium 31 having the conventional structure shown in FIG.

[0226]

[Table 6]

As shown in Table 6, only (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) was used for the material of the first dielectric layer 2.
In the information recording medium 26 of the sample number 6-1 of this embodiment, the total number of layers (that is, the layers up to the reflective layer 8) formed on the substrate 1 by the sputtering method is 6 layers. The adhesiveness, the number of repetitions, the peak power, and the bias power equivalent to those of the information recording medium 31 having the conventional structure of seven layers were obtained. In this example, the first dielectric layer 2 was made of (ZrSiO ₄ ) ₅₄ (ZnS) _{4 6} (mo
layer (Zr—Zn—S) having a composition of 1%).
-O-based material layer) was used, but this composition is an example, and Z
With the rSiO ₄ —ZnS-based material, good results were obtained as in the present example over the composition range in which the ZrSiO ₄ content was 33 to 67 mol%. Further, another Zr—Zn—S—O-based material layer may be used as the first dielectric layer 2.

Example 7 In Example 7, the third embodiment will be described.
1. The first dielectric layer has the same structure as the information recording medium 27 described above with reference to FIG. 3, and the first dielectric layer and the second dielectric layer are made of materials having different compositions. An information recording medium having a first interface layer between the recording layer and the recording layer was produced.

The information recording medium 27 of this example was manufactured as follows. First, a substrate 1 similar to that of Example 1 was prepared, and (ZnS) ₈₀ (SiO ₂ ) was formed on the substrate 1.
The first dielectric layer 102 of ₂₀ (mol%) has a thickness of 150 nm, and the first interface layer 103 of Ge—Cr—N has a thickness of 5 nm.
The recording layer 4 of Ge ₂₇ Sn ₈ Sb ₁₂ Te ₅₃ (atomic%) with a thickness of 9 nm and a thickness of (ZrSiO ₄ ) ₅₄ (ZnS).
₄₆ second dielectric layer 6 with a thickness of 50 nm and Ge ₈₀ Cr
₂₀ (atomic%) of the light absorption correction layer 7 with a thickness of 40 nm
The reflective layer 8 of g-Pd-Cu having a thickness of 80 nm was sequentially formed by the sputtering method. Here, the respective materials of the first dielectric layer 102 and the first interface layer 103 are the same as those in the conventional information recording medium 31 described above with reference to FIG.

In the information recording medium 27 of this embodiment, a film forming process of the first interface layer 103 is added between the film forming process of the first dielectric layer 102 and the film forming process of the recording layer 4. Further, it was produced in the same manner as the information recording medium of sample number 1-1 of Example 1 except that the film forming process of the second dielectric layer 6 was changed. The step of forming the first interface layer 103 was performed in the same manner as the step of forming the first interface layer in the method of manufacturing the information recording medium 31 having the conventional configuration of the comparative example described in Example 1. . In the step of forming the second dielectric layer 6, a sputtering target (diameter 100 mm, thickness 6 mm) having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ is used, and the gas introduced into the film forming apparatus is Ar gas. (100%), the power was 400 W, and the pressure was about 0.13 Pa. The first dielectric layer 10
The step of forming the second dielectric film 2 is similar to the step of forming the first dielectric layer 2 in the method of manufacturing the information recording medium 25 of the sample number 1-1 described in the first embodiment. This is also the same as the step of forming the first dielectric layer 2 in the method of manufacturing the recording medium 31.

Regarding the information recording medium 27 of sample No. 7-1 of this example obtained as described above, the adhesion of the dielectric layer and the rewritability of the information recording medium were described above in Example 1. However, in this example, the adhesion was evaluated by checking whether peeling occurred between the recording layer 4 and the second dielectric layer 6 in contact with the recording layer 4. Carried out. These results
Table 7 shows the peak power (Pp) obtained at the time of evaluating the repetitive rewriting performance.

[0232]

[Table 7]

As shown in Table 7, only (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) was used for the material of the second dielectric layer 6.
In the information recording medium 27 of sample No. 7-1 of this example, in which the number of layers (that is, the layers up to the reflective layer 8) formed on the substrate 1 by the sputtering method is 6 using The adhesiveness, the number of repetitions, the peak power, and the bias power equivalent to those of the information recording medium 31 having the conventional structure of seven layers were obtained. Further, the measured Rc value (on the flat portion having no unevenness) of the information recording medium 27 of sample number 7-1 manufactured in this example was 20%, and the measured Ra value was 3%. In the present embodiment, the second dielectric layer 6
As (ZrSiO ₄ ) ₅₄ (ZnS) _{4 6} (mol%)
A layer (Zr—Zn—S—O-based material layer) made of a material having the composition described above was used, but this composition is an example.
In the O ₄ —ZnS-based material, the content ratio of ZrSiO ₄ is 33
Good results were obtained as in this example over the composition range of ˜67 mol%. In addition, the second dielectric layer 6
Alternatively, another Zr—Zn—S—O-based material layer may be used.

Example 8 In Example 8, Embodiment 4 will be described.
Then, an information recording medium having the same structure as the information recording medium 28 described above with reference to FIG. 4 was produced.

The information recording medium 28 of this example was manufactured as follows. First, as the substrate 101, a depth of 21n
m, track pitch (distance between the groove surface and the center of the groove surface in a plane parallel to the main surface of the substrate) 0.3
2 μm diameter guide groove with a diameter of 12
A circular polycarbonate substrate having a thickness of 0 mm and a thickness of 1.1 mm was prepared.

On this substrate 101, Ag-Pd-Cu is formed.
And a reflective layer 8 having a two-layer structure of AlCr and 80 n respectively.
m and a thickness of 10 nm, (ZrSiO ₄ ) ₅₄ (Zn
S) _{4 6} a second dielectric layer 6 of (mol%) with a thickness of 16 nm, a Ge _37.5 Sb ₁₁ Te _51. recording layer 4 of the ₅ (atomic%) with a thickness of 11 nm, (ZrSiO _{4) 54} (ZnS)
₄₆ (mol%) of the first dielectric layer 2 having a thickness of 68 nm was sequentially formed by the sputtering method.

The step of forming the reflective layer 8 was carried out as follows. First, a layer of Ag-Pd-Cu was formed in Example 1
It was formed in the same manner as in the film forming step of the reflective layer in the method of manufacturing the information recording medium of Sample No. 1-1. Then A
A sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of 1Cr was attached to a film forming apparatus, Ar gas (100%) was introduced, and a sputtering target of about 0.4P was obtained.
Direct-current sputtering was performed with a power of 200 W under the pressure of a. This allows AlCr on the Ag-Pd-Cu layer.
Then, the reflective layer 8 having a two-layer structure was formed.

In the step of forming the second dielectric layer 6, a sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) _{4 6} (mol%) is formed. It was attached to a film apparatus, Ar gas (100%) was introduced with a power of 400 W, and high frequency sputtering was performed under a pressure of about 0.13 Pa.

In the step of forming the recording layer 4, Ge is used.
A sputtering target (diameter 100 mm, thickness 6 mm) made of a —Sb—Te-based material was attached to a film forming apparatus, and a mixed gas of Ar gas (97%) and N ₂ gas (3%) was introduced with a power of 100 W to form a direct current. Sputtering was performed. The pressure during sputtering was about 0.13 Pa.

The step of forming the first dielectric layer 2 includes the first step.
Of the second dielectric layer 6 except that the layer thickness is changed so that the dielectric layer 2 and the second dielectric layer 6 have substantially the same composition. It was carried out.

As described above, after the reflective layer 8, the second dielectric layer 6, the recording layer 4 and the first dielectric layer 2 are sequentially formed on the substrate 101 to form a laminated body, ultraviolet rays are applied. A curable resin is applied on the first dielectric layer 2 and a diameter of 120 m is used as a dummy substrate 110 on the applied ultraviolet curable resin.
A circular polycarbonate substrate having a thickness of m and a thickness of 90 μm was adhered. Then, the resin was cured by irradiating ultraviolet rays from the dummy substrate 110 side. As a result, the adhesive layer 9 made of the cured resin was formed to a thickness of 10 μm, and the dummy substrate 110 was attached to the laminated body via the adhesive layer 9.

After the bonding, the wavelength 6 is used as an initialization process.
Using a 70 nm semiconductor laser, the recording layer 4 of the information recording medium 28 was crystallized over almost the entire area within an annular region having a radius of 22 to 60 mm. As a result, the initialization process was completed, and the production of the information recording medium 28 of sample number 8-1 was completed.

In addition, for comparison, the first dielectric layer 2
And a recording layer 4, and between the second dielectric layer 6 and the recording layer 4, a Ge—Cr—N first interface layer 103 and a second interface layer 105, respectively, and In place of the first dielectric layer 2 and the second dielectric layer 6, (ZnS)
₈₀ (SiO ₂ ) ₂₀ (mol%) first dielectric layer 102
An information recording medium of a comparative example having the same structure as the information recording medium of the present example except that the second dielectric layer 106 is provided (not shown). First interface layer 10
Both 3 and the second interface layer 105 were formed to have a thickness of 5 mm.

In the information recording medium of this comparative example, the steps of forming the first interface layer 103 and the second interface layer 105, and the first dielectric layer 102 and the second dielectric layer 106.
The method for producing the information recording medium of the present example, except that the step of forming a film is carried out in the same manner as in the method for producing the information recording medium 31 of the conventional configuration of the comparative example produced in Example 1. Was prepared in the same manner as in.

Sample No. 8 obtained as described above
With respect to the information recording medium 28 of No. 1 and the information recording medium of the comparative example (not shown), the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated. These results are shown in Table 8 together with the peak power (Pp) obtained at the time of evaluating the rewriting performance.

In this example, the adhesion of the dielectric layer on the information recording medium 28 was evaluated under the same conditions as in Example 1. On the other hand, the evaluation of the repetitive rewriting performance of the information recording medium 28 is similar to that of the first embodiment in that the number of repetitions is used as an index, but is different from that of the first embodiment.

In evaluating the repetitive rewriting performance of the information recording medium 28, a semiconductor laser having a wavelength of 405 nm and an objective lens having a numerical aperture of 0.85 were used in an information recording system having the same structure as in Example 1, and 23 GB was used. Recording was made corresponding to the capacity. The linear velocity for rotating the information recording medium 28 is 5
m / sec. A spectrum analyzer was used to measure the CNR (that is, the ratio of signal amplitude to noise) and the erasure rate.

First, the peak power (Pp) and the bias power (Pb) were set in the following procedure in order to determine the measurement conditions when determining the number of repetitions. Laser light 1
2 is irradiated toward the information recording medium 28 while performing power modulation between the peak power (mW) at the high power level and the bias power (mW) at the low power level, and a 2T signal having a mark length of 0.16 μm is emitted. Recording was performed 10 times on the same groove surface of the recording layer 4. After recording 2T signal 10 times, C
The NR was measured. When recording 2T signals 10 times, the CNR was measured under each recording condition in which the bias power was fixed to a constant value and the peak power was variously changed, and the minimum peak power of 1.2 when the signal amplitude was saturated was measured. Double power was set to Pp. In addition, the 2T signal is set to 1 in the same manner as above.
After recording 0 times, the signal is reproduced to measure the amplitude of the 2T signal, and the 9T signal is overwritten once on the groove surface, and the signal is reproduced to measure the amplitude of the 2T signal, and recorded 10 times. The attenuation rate of the 2T signal based on the amplitude measured later was determined as the erasing rate. At the time of recording 2T signal 10 times and overwriting 9T signal 1 time, the peak power was set to P first.
For each power condition that is fixed to p and the bias power is variously changed, the erasing rate defined as above is obtained,
The center value of the bias power range where the erasing rate was 25 dB or more was set to Pb. Considering the laser power upper limit of the system, it is desirable to satisfy Pp ≦ 7 mW and Pb ≦ 3.5 mW.

The number of times of repetition, which is an index of repetitive rewriting performance, was determined based on the CNR and the erasing rate in this embodiment. After the laser light is power-modulated by Pp and Pb set as described above, the information recording medium 28 is irradiated and the 2T signal is continuously recorded on the same groove surface a predetermined number of times continuously, and then the CNR is measured. Then, the erasing rate was calculated. Similarly to the above, the erasure rate is 2 after the recording is performed a predetermined number of times and the 9T signal is once overwritten thereon.
The T signal was measured, and the amplitude of the 2T signal was recorded for a predetermined number of times, and the attenuation rate of the amplitude of the 2T signal measured after the 9T signal was overwritten once was calculated. The number of repetitions is 1, 2, 3, 5, 10, 100, 200, 50
0, 1000, 2000, 3000, 5000, 700
It was 0, 10,000 times. CN when repeated 10 times
Based on R and the erasure rate, when the CNR decreased by 2 dB or the erasure rate decreased by 5 dB, it was judged to be the limit of repetitive rewriting, and the rewriting performance was evaluated by the number of times of repetition at this time. Of course, the larger the number of repetitions, the higher the repetitive rewriting performance. The number of repetitions of the information recording medium 28 is preferably 10,000 or more.

[0250]

[Table 8]

In the information recording medium 28 of sample No. 8-1 of the present example, the order of film formation of each layer on the substrate is opposite to that of the information recording medium 25 shown in FIG. The first dielectric layer 2 and the second dielectric layer 6 are made of (Zr) regardless of the fact that the laser wavelength and the numerical aperture of the lens are different and the recording capacity is increased by about 5 times.
By using a layer (Zr—Zn—S—O-based material layer) made of a material having a composition of SiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%), good performance can be obtained without providing an interface layer. It was Further, the measured Rc value (on the flat portion having no unevenness) of the information recording medium 28 of Sample No. 8-1 manufactured in this example was 20%, and the measured Ra value was 3%. From Table 8, information recording medium 2 of sample number 8-1
It was confirmed that No. 8 exhibited the same performance as the information recording medium of the comparative example provided with the first and second interface layers.

In the information recording medium 28 of sample No. 8-1 of this example, Zr was formed on both the first and second dielectric layers.
Although the layer made of the SiO ₄ —ZnS-based material is used, another Zr—Zn—S—O-based material layer may be used.

In the information recording medium 28 of this embodiment,
Zr—Zn—S—O for both the first and second dielectric layers
Although the system material layer is used, the present invention is not limited to this. As an example, a Zr—Zn—S—O-based material layer is used for one of the first and second dielectric layers, and the other dielectric layer is formed of, for example, conventional (ZnS) ₈₀ (SiO ₂ ) _{2 0.}
A material having a composition of (mol%) may be used, and an interface layer may be provided between the other dielectric layer and the recording layer. Also in this case, the same result as that of this example was obtained. Therefore, by using the Zr—Zn—S—O-based material layer as the dielectric layer, at least one of the two interface layers conventionally used between the first and second dielectric layers and the recording layer is used. On the other hand, it is possible to reduce both, and it is possible to secure the same performance as that of the information recording medium of the comparative example.

Example 9 In Example 9, Embodiment 5 will be described.
Then, an information recording medium having the same structure as the information recording medium 29 described above with reference to FIG. 5 was produced.

The information recording medium 29 of this example was manufactured as follows. First, the same substrate 101 as in Example 8 was prepared, and the second reflective layer 20 having a two-layer structure of Ag—Pd—Cu and AlCr was formed on the substrate 101 by 80.
nm and 10 nm thick, (ZrSiO ₄ ) ₄₃ (Z
nS) ₅₇ (mol%) of the fifth dielectric layer 19 of 16 nm
The second recording layer 18 of Ge _37.5 Sb ₁₁ Te _51.5 (atomic%) with a thickness of 11 nm and a thickness of (ZrSiO ₄ )
₄₃ (ZnS) ₅₇ (mol%) of the fourth dielectric layer 17
A film having a thickness of 8 nm was sequentially formed by a sputtering method. As a result, the second information layer 22 was formed on the substrate 101.

Second reflective layer 20 and second recording layer 18
The step of forming a film was performed under the same conditions as the step of forming the reflective layer 8 and the recording layer 4 in the method of manufacturing the information recording medium 28 of Example 8. In addition, the step of forming the fifth dielectric layer 19 and the fourth dielectric layer 17 includes
A sputtering target (diameter: 1) having a composition of (ZrSiO ₄ ) ₄₃ (ZnS) ₅₇ (mol%)
Example 8 except that a thickness of 00 mm and a thickness of 6 mm) was used.
The process was performed under the same conditions as the steps of forming the second dielectric layer 6 and the first dielectric layer 2 in the method of manufacturing the information recording medium 28.

Next, an ultraviolet curable resin is applied on the second information layer 22 by, for example, spin coating, and a polycarbonate substrate having guide grooves on the surface is applied on the applied ultraviolet curable resin. The guide groove is placed in close contact. Then, the polycarbonate substrate was irradiated with ultraviolet rays to cure the resin, and the polycarbonate substrate was peeled from the intermediate layer 16. As a result, the intermediate layer 16 made of the cured resin and having the transferred grooves was formed with a thickness of 30 μm.

Then, as the first initialization step, the wavelength 6
The 70 nm semiconductor laser was used to crystallize the second recording layer 18 of the second information layer 22 over substantially the entire area within an annular region having a radius of 22 to 60 mm.

Next, 15 n of a third dielectric layer 15 of TiO ₂ is formed on the intermediate layer 16 of the laminated body obtained as described above.
The first reflective layer 14 made of Ag-Pd-Cu has a thickness of 1 m.
With a thickness of 0 nm, (ZrSiO ₄ ) ₄₃ (ZnS) ₅₇ (m
ol%) second dielectric layer 6 with a thickness of 12 nm and Ge
The first recording layer 13 of ₃₈ Sb ₁₀ Te ₅₂ (atomic%) is set to 6 nm.
Thickness of (ZrSiO ₄ ) ₄₃ (ZnS) ₅₇ (mol
%) Of the first dielectric layer 2 having a thickness of 45 nm was sequentially formed by the sputtering method. As a result, the first information layer 21 was formed. If necessary, the first reflective layer 1
5n of Cr ₂ O ₃ thin film layer between the second dielectric layer 6 and the second dielectric layer 6
It may be provided with a thickness of m.

In the step of forming the third dielectric layer 15, a sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of TiO ₂ was used, and a power of 400 W and Ar gas (97%) were used. A mixed gas with O ₂ gas (3%) was introduced, and high frequency sputtering was performed under a pressure of about 0.13 Pa.

The step of forming the first reflection layer 14 is the same as the formation conditions of the Ag-Pd-Cu layer in the second reflection layer 20 except that the layer thickness is changed. Carried out.

The step of forming the second dielectric layer 6 is performed by (Z
A sputtering target (diameter 100 mm, thickness 6) made of a material having the composition of rSiO ₄ ) ₄₃ (ZnS) _57.
mm) is attached to the film forming apparatus, and the power is 500 W and Ar
High frequency sputtering was performed under a pressure of about 0.13 by introducing gas (100%).

In the step of forming the first recording layer 13, a sputtering target (diameter 100 mm, thickness 6 mm) made of a Ge—Sb—Te-based material was attached to the film forming apparatus, the power was 50 W, and the Ar gas (100 mm) was used. %) Was introduced and DC sputtering was performed. The pressure during sputtering was about 0.13 Pa.

The step of forming the first dielectric layer 2 includes the first step.
Of the second dielectric layer 6 except that the layer thickness is changed so that the dielectric layer 2 and the second dielectric layer 6 have substantially the same composition. It was carried out.

After the first dielectric layer 2 is formed on the substrate 101 to form a laminated body as described above, an ultraviolet curable resin is applied on the first dielectric layer 2. A dummy substrate 110 having a diameter of 1 is formed on the applied ultraviolet curable resin.
A circular polycarbonate substrate having a thickness of 20 mm and a thickness of 65 μm was adhered. Then, the resin was cured by irradiating ultraviolet rays from the dummy substrate 110 side. As a result, the adhesive layer 9 made of the cured resin was formed to a thickness of 10 μm, and the dummy substrate 110 was attached to the laminated body via the adhesive layer 9.

After the bonding, as a second initialization step,
Using the semiconductor laser having a wavelength of 670 nm, the first information layer 2
The first recording layer 13 of No. 1 was crystallized over almost the entire area within an annular region having a radius of 22 to 60 mm. This completes the production of the information recording medium 29 of sample number 9-1.

Sample No. 9 obtained as described above
Regarding the information recording medium 29 of -1, the adhesion of the dielectric layer and the rewritability of the information recording medium were evaluated for each of the first information layer 21 and the second information layer 22. These results are shown in Table 9 together with the peak power (Pp) and the bias power (Pb) obtained when the repeated rewriting performance was evaluated.

In this example, the adhesion of the dielectric layer on the information recording medium 29 was evaluated under the same conditions as in Example 1, but the first information layer 21 and the second information layer 22 were peeled off. The difference is that the presence or absence of is checked. The evaluation of the repetitive rewriting performance of the information recording medium 29 was performed under substantially the same conditions as in Example 8.
Recording corresponding to a 23 GB capacity is performed on each of the information layer 21 and the second information layer 22, and the first information layer 21 and the second information layer 22 are recorded.
The difference is that the number of repetitions was examined for each of the.
When recording on the first information layer 21, the laser beam 12 is first
When recording the second information layer 22 by focusing on the recording layer 13 of No. 2, the laser beam 12 was focused on the second recording layer 18.
Considering the laser power upper limit of the system, Pp ≦ 14 mW and Pb ≦ 7 mW in the first information layer 21 (the second information layer 22 uses the laser light 12 that has passed through the first information layer 21. And about half the value of Pb).

[0269]

[Table 9]

As shown in Table 9, in the information recording medium 29 of sample No. 9-1 of this example, the order of film formation of each layer on the substrate was higher than that of the information recording medium 25 shown in FIG. Despite the opposite, that there are two or more information layers on the substrate, that the recording conditions are different, and that the recording capacity has increased by about 10 times, the first dielectric layer 2 and the second dielectric layer 2 Good performance was obtained by using, as the body layer 6, the fourth dielectric layer 17, and the fifth dielectric layer 19, layers made of a ZrSiO ₄ —ZnS-based material. In addition, the information recording medium 29 of sample number 9-1 produced in this example
Rc of the first information layer 21 (in the flat portion having no unevenness)
The design value was 6% and the Ra design value was 0.7%. The Rc design value of the second information layer 22 was 25%, and the Ra design value was 3%.

In the information recording medium 29 of sample No. 9-1 of this example, the first dielectric layer 2, the second dielectric layer 6,
Although a layer made of a ZrSiO ₄ —ZnS-based material is used for all of the fourth dielectric layer 17 and the fifth dielectric layer 19, another Zr—Zn—S—O-based material layer (for example, ZrO ₂
Good performance was obtained even when a layer made of a material of the type —SiO ₂ —ZnS and having different contents of ZrO ₂ and SiO ₂ ) was used as the dielectric layer.

In the information recording medium 29 of this embodiment,
Zr-Zn-S is formed on all of the first dielectric layer 2, the second dielectric layer 6, the fourth dielectric layer 17, and the fifth dielectric layer 19.
Although the -O-based material layer is used, the present invention is not limited to this. As an example, a Zr—Zn—S—O-based material layer is used for at least one of these dielectric layers, and the remaining dielectric layers are formed of, for example, conventional (ZnS) ₈₀ (SiO ₂ ) ₂₀
A material having a composition of (mol%) may be used, and an interface layer may be provided between the remaining dielectric layer and the recording layer. Also in this case, the same results as in this example were obtained.

Furthermore, in the information recording medium 29 of the present embodiment, all of the first dielectric layer 2, the second dielectric layer 6, the fourth dielectric layer 17 and the fifth dielectric layer 19, Although material layers of the same composition were used, materials of different composition could be used for at least any two of these dielectric layers. Even in that case, a good performance comparable to the result of this example was obtained.

Example 10 In Example 10, the information recording medium 30 described in the sixth embodiment with reference to FIG. 6 was used.
An information recording medium having the same structure as the above was produced. In the information recording medium 30 of this embodiment, the first embodiment described above is used.
No. 1 to 9 are different from the dielectric layer in the information recording medium.
On the interfacial layer 3 and the second interfacial layer 5 of
It uses a system material layer.

The information recording medium 30 of this example was manufactured as follows. First, the same substrate 1 as in Example 1 was prepared, and (ZnS) ₈₀ (SiO ₂ ) was added on the substrate 1.
The first dielectric layer 102 of ₂₀ (mol%) with a thickness of 150 nm is formed by (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%).
The first interface layer 3 of 5 nm thick with Ge ₂₇ Sn ₈ Sb
The recording layer 4 of ₁₂ Te ₅₃ (atomic%) is formed with a thickness of 9 nm (Z
The second interfacial layer 5 of rSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) is formed to a thickness of 5 nm, and is (ZnS) ₈₀ (SiO ₂ ).
The second dielectric layer 106 of ₂₀ (mol%) is formed to a thickness of 50 nm, and the light absorption correction layer 7 of Ge ₈₀ Cr ₂₀ (atomic%) is formed to 40 nm.
The reflective layer 8 of Ag-Pd-Cu has a thickness of 80 nm.
The film having the thickness of 1 was sequentially formed by the sputtering method. Here, the first dielectric layer 102 and the second dielectric layer 106.
The respective materials are the same as those provided in the conventional information recording medium 31 described above with reference to FIG.

This information recording medium 30 includes the first interface layer 3
And the information recording medium 31 of the conventional configuration (see FIG. 9) produced in Example 1 except that the material of the second interface layer 5 is different. Second
The film was formed in the same manner as the above except the film forming process of the interface layer 5. In the film forming process of the first interface layer 3 and the second interface layer 5, a sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) is formed. It was attached to a film apparatus, Ar gas (100%) was introduced with a power of 400 W, and high frequency sputtering was performed under a pressure of about 0.13 Pa.

Sample number 1 obtained as described above
With respect to the information recording medium 30 of 0-1, the adhesion of the dielectric layer and the repeated rewriting performance of the information recording medium were evaluated in substantially the same manner as described above in Example 1. The evaluation was made whether peeling occurred between the recording layer 4 and the interface layer in contact with the recording layer 4, more specifically, between the recording layer and at least one of the first interface layer 3 and the second interface layer 5. It was carried out by investigating. Further, the repetitive rewriting performance was evaluated by performing land recording as well as groove recording (that is, by land-groove recording) and examining the number of repetitions of each of groove recording and land recording. The results are shown in 10. In addition, for comparison, Table 10 also shows the result of the similar evaluation of the information recording medium 31 of the conventional structure shown in FIG.

[0278]

[Table 10]

As shown in Table 10, the material of the interface layer is (Z
The information recording medium 30 of sample No. 10-1 of this example using rSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol%) provided the same performance as the information recording medium 31 of the conventional structure of the comparative example.

According to this embodiment, Zr-Z is used as the interface layer.
The number of layers of the information recording medium is the same as the conventional one, using the n-S-O-based material layer, and does not decrease. However, such Zr-Z
The interface layer made of an n-S-O-based material is a conventional Ge-Cr
Unlike the -N interface layer, which does not rely on reactive sputtering,
It can be formed by sputtering in an atmosphere of only Ar gas. Therefore, according to this embodiment, the composition variation and the film thickness distribution of the interface layer itself are smaller than those of the conventional Ge-Cr-N interface layer, and the easiness of manufacture and the stability can be improved.

In the information recording medium 30 of sample No. 10-1 of this example, (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ (mol) was used as the first interface layer 3 and the second interface layer 5.
%) Of the layer (Zr-Zn-S-
O-based material layer) was used, but this composition is an example, and another Zr—Zn—S—O-based material layer may be used. Further, as the first interface layer 3 and the second interface layer 5, Zr—Zn—S—O based material layers having different compositions may be used.

Example 11 In Example 11, the information recording medium 28 explained in Embodiment 4 with reference to FIG.
An information recording medium having the same structure as was prepared by changing the material of the recording layer 4 variously.

In the information recording medium 28 of this example, both the second dielectric layer and the first dielectric layer are (ZrO ₂ ) ₅₀ (S
iO ₂ ) ₃₀ (ZnS) ₂₀ (mol%), and the material of the recording layer is shown in Table 11 (that is, for each sample,
Ge ₃₅ Sn ₁₀ Sb ₄ Te ₅₁ (atomic%), Ge ₄₅ Bi ₄ Te
₅₁ (atomic%), Ge ₄₂ Sn ₃ Bi ₄ Te ₅₁ (atomic%), G
e ₄₅ Sb ₂ Bi ₂ Te ₅₁ (atomic%), Ge ₄₂ Sn ₃ Sb ₃ B
i ₁ Te ₅₁ (atomic%), Ag ₂ In ₃ Sb ₇₇ Te ₁₈ (atomic%) and Sb ₇₇ Te ₁₈ Ge ₅ (atomic%)), the same as the information recording medium 28 of Example 8. And the same procedure except that the steps of forming the first and second dielectric layers and the steps of forming the recording layer were changed.

As in the eighth embodiment, A
The reflective layer 8 having a two-layer structure of g-Pd-Cu and AlCr
At thicknesses of 80 nm and 10 nm respectively, (Zr
O₂)₅₀(SiO₂)₃₀(ZnS)₂₀(Mol%) second
The dielectric layer 6 of 16 nm thick and made of the material shown in Table 11
The recording layer 4 consisting of 11 nm, (ZrO₂)₅₀(SiO₂)
₃₀(ZnS)₂₀(Mol%) of the first dielectric layer 2 is 68
Films having a thickness of nm were sequentially formed by a sputtering method.

In order to manufacture the information recording medium 28 of this example, in the film forming process of the first dielectric layer and the second dielectric layer, (ZrO ₂ ) ₅₀ (SiO ₂ ) ₃₀ (ZnS) was used.
_A sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of ₂₀ (mol%) was used. Further, in the film forming process of the first dielectric layer and the second dielectric layer, the power was 400 W, the pressure was about 0.13 Pa, and the gas introduced into the film forming apparatus was Ar for all samples. Gas (100%) was used.

Further, in order to manufacture the information recording mediums 28 of sample numbers 11-1 to 11-7, in the film forming process of the recording layer, the sputtering target (diameter of the material having the predetermined composition shown in Table 11 (diameter 100 mm and a thickness of 6 mm) were used. Further, in the film forming process of the recording layer, the power was 100 W, the pressure was about 0.13 Pa, and the gas introduced into the film forming apparatus was Ar gas (97%) and N ₂ gas (3%) for all the samples. %) Was used.

The recording layer formed by the sputtering method was considered to have substantially the same composition as the sputtering target used.

The other film forming process, bonding process and initialization process are the same as in the eighth embodiment.

Sample No. 1 obtained as described above
About the information recording mediums 1-1 to 11-7, the adhesion of the dielectric layer and the rewritable performance of the information recording medium were evaluated in substantially the same manner as in Example 8. These results
Table 11 shows the peak power (Pp) obtained in the evaluation of the repetitive rewriting performance. The evaluation condition of the information recording medium 28 is different from the evaluation condition of Example 8 in that the linear velocity for rotating the information recording medium was 10 m / sec. Other than that, as in the case of Example 8, a semiconductor laser having a wavelength of 405 nm and an objective lens having a numerical aperture of 0.85 were used, and recording corresponding to a 23 GB capacity was performed on the groove surface.

[0290]

[Table 11]

According to Table 11, even if the material of the recording layer 4 was variously changed, a high adhesion, a high number of repetitions and an appropriate power level were obtained under the condition of the linear velocity of 10 m / sec. Thus, (ZrO ₂ ) ₅₀ (SiO ₂ ) ₃₀ (Z
When a material composed of nS) ₂₀ (mol%) was used as the material for the first and second dielectric layers, good performance was obtained in the information recording medium having no interface layer.

(Embodiment 12) In the above Embodiments 1 to 11, an information recording medium for recording information by optical means was produced. In Embodiment 12, however, information is recorded by electric means as shown in FIG. An information recording medium 207 for recording was prepared. The information recording medium 207 of this embodiment is a so-called memory.

The information recording medium 207 of this example was manufactured as follows. First, nitriding the surface, length 5m
A Si substrate 201 having a size of m, a width of 5 mm and a thickness of 1 mm is prepared, and an Au lower electrode 202 is provided on the substrate 201 in a region of 1.0 mm × 1.0 mm with a thickness of 0.1 μm.
The phase change portion 205 of e ₃₈ Sb ₁₀ Te ₅₂ (which is expressed as Ge ₈ Sb ₂ Te ₁₁ as a compound) was formed in a circular region having a diameter of 0.2 mm with a thickness of 0.1 μm, and (ZrSiO ₄ ) ₅₄ (ZnSiO ₄ ) ₅₄ (ZnSiO ₄ ).
S) The heat insulating part 206 of _{46 has} the same thickness as the phase change part 205 in the area of 0.6 mm × 0.6 mm (excluding the phase change part 205), and the upper electrode 204 of Au is 0.6 mm × 0.6 m.
m region with a thickness of 0.1 μm was sequentially laminated by a sputtering method.

In the step of forming the phase change portion 205, Ge is used.
A sputtering target (diameter 100 mm, thickness 6 mm) made of a —Sb—Te-based material was attached to a film forming apparatus, and a DC mixed gas was introduced at a power of 100 W by introducing a mixed gas of Ar gas (100%). The pressure during sputtering was about 0.13 Pa. Further, in the step of forming the film of the heat insulating section 206, a sputtering target (diameter 100 mm, thickness 6 mm) made of a material having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ was attached to the film forming apparatus, and a power of 500 W was used to supply Ar gas. (100%) was introduced, and high frequency sputtering was performed under a pressure of about 0.13 Pa. The sputtering in these steps is performed by the phase change part 2
05 and the heat insulating portion 206 were covered with a mask jig so that the regions other than the surface on which the film was to be formed were covered so as not to be laminated on each other. The order of forming the phase change portion 205 and the heat insulating portion 206 is not limited, and either of them may be formed first.

The phase change section 205 and the heat insulation section 206 constitute the recording section 203. The phase change section 205 corresponds to the recording layer in the present invention, and the heat insulation section 206 corresponds to the Zr-Zn- in the present invention. It corresponds to the S-O based material layer.

Since the step of forming the lower electrode 202 and the step of forming the upper electrode 204 can be carried out by a general method in the field of electrode forming technology by the sputtering method, detailed description thereof will be omitted.

It was confirmed by the system shown in FIG. 8 that a phase change occurred in the phase change section 205 when electric energy was applied to the information recording medium 207 of this example manufactured as described above. The sectional view of the information recording medium 207 shown in FIG. 8 shows a section taken along the line AB of the information recording medium 207 shown in FIG. 7 in the thickness direction.

More specifically, as shown in FIG. 8, the two application portions 212 are bonded to the lower electrode 202 and the upper electrode 204 by Au lead wires respectively, so that electrical writing / reading is performed via the application portions 212. The device 214 was connected to the information recording medium (memory) 207.
In this electrical writing / reading device 214, a pulse generator 208 is provided between the lower electrode 202 and an upper electrode 204, and a pulse generator 208 is provided between the applying parts 212.
10 and the resistance measuring instrument 209 was connected via the switch 211. Resistance measuring instrument 209
Was connected to the determination unit 213 that determines whether the resistance value measured by the resistance measuring device 209 is high or low. The pulse generator 208 applies the upper electrode 204 via the applying unit 212.
A current pulse is caused to flow between the lower electrode 202 and the lower electrode 202, and the resistance value between the lower electrode 202 and the upper electrode 204 is measured by the resistance measuring instrument 209.
It was judged by 3. In general, the resistance value changes due to the phase change of the phase change unit 205, so that the state of the phase of the phase change unit 205 can be known based on the determination result.

In the case of this embodiment, the melting point of the phase change portion 205 is 630 ° C., the crystallization temperature is 170 ° C., and the crystallization time is 130.
It was ns. The resistance value between the lower electrode 202 and the upper electrode 204 is 1000 when the phase change portion 205 is in the amorphous phase state.
Ω, and 20Ω in the crystalline phase state. When the phase change portion 205 is in an amorphous phase state (that is, a high resistance state), the lower electrode 20
When a current pulse of 20 mA and 150 ns is applied between the upper electrode 204 and the upper electrode 204, the resistance value between the lower electrode 202 and the upper electrode 204 decreases, and the phase change portion 205 changes from the amorphous phase state to the crystalline phase state. Transferred to. Next, the phase change unit 20
When 5 is in a crystalline phase state (that is, a low resistance state), the lower electrode 2
02 and the upper electrode 204, 200mA, 100ns
When the current pulse was applied, the resistance value between the lower electrode 202 and the upper electrode 204 increased, and the phase change portion 205 transitioned from the crystalline phase to the amorphous phase.

From the above results, a layer made of a material having a composition of (ZrSiO ₄ ) ₅₄ (ZnS) ₄₆ was used as the heat insulating portion 206 around the phase change portion 205, and the phase change portion was obtained by applying electric energy. A phase transformation can be caused in the (recording layer), and therefore the information recording medium 207
However, it was confirmed that it has a function of recording information.

As in this embodiment, the columnar phase change portion 20 is
Around ( ₅ ) is (ZrSiO ₄ ) ₅₄ (Zn
S) ₄₆ provided with the heat insulating portion 206 effectively reduces the escape of the current flowing in the phase change portion 205 to the peripheral portion thereof by applying a voltage between the upper electrode 204 and the lower electrode 202, Therefore, the temperature of the phase change portion 205 can be efficiently raised by the Joule heat generated by the current. In particular, when the phase change portion 205 is transformed to the amorphous phase state, Ge ₃₈ Sb ₁₀ of the phase change portion 205 is used.
It is necessary to melt Te ₅₂ once and quench it.
By providing the heat insulating portion 206 around the phase change portion 205, the temperature of the phase change portion 205 can be raised to the melting point or higher with a smaller current.

The (ZrSiO ₄ ) ₅₄ (Zn
Since S) ₄₆ has a high melting point and atomic diffusion due to heat hardly occurs, it can be applied to an electric memory such as the information recording medium 207. Further, when the heat insulating portion 206 exists around the phase change portion 205, the heat insulating portion 206 serves as a barrier and the phase change portion 205 is substantially electrically and thermally isolated within the plane of the recording portion 203. It is possible to increase the memory capacity of the information recording medium 207 and improve the access function and the switching function by providing the information recording medium 207 with a plurality of phase change portions 205 separated from each other by the heat insulating portion 206. It is also possible to connect a plurality of information recording media 207 themselves.

Although the information recording medium of the present invention has been described above through various embodiments, Zr-Zn-S can be used for both the information recording medium for recording by optical means and the information recording medium for recording by electric means. An —O-based material layer can be used, and according to such an information recording medium of the present invention,
An excellent effect can be obtained as compared with the conventional information recording medium.

[0304]

According to the present invention, the dielectric layer formed in direct contact with the recording layer is preferably a ZrO _2- (Zn--S) type material, a ZrO ₂ --SiO _2- (Zn--S) type material or a Zr.
It is characterized by being formed of a SiO ₄ — (Zn—S) -based material. According to this feature, the interface layer between the recording layer and the dielectric layer, which the conventional optical information recording medium has, is eliminated,
It is possible to realize an optical information recording medium in which the number of layers can be reduced, reliability is high, and excellent rewritability and high recording sensitivity are ensured. Further, if layers of these materials are used as a dielectric layer for insulating the recording layer in an information recording medium to which electric energy is applied, a small electric energy can cause a phase change of the recording layer. it can.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an example of an optical information recording medium of the present invention.

FIG. 2 is a partial cross-sectional view showing another example of the optical information recording medium of the present invention.

FIG. 3 is a partial cross-sectional view showing still another example of the optical information recording medium of the present invention.

FIG. 4 is a partial cross-sectional view showing still another example of the optical information recording medium of the present invention.

FIG. 5 is a partial cross-sectional view showing still another example of the optical information recording medium of the present invention.

FIG. 6 is a partial cross-sectional view showing still another example of the optical information recording medium of the present invention.

FIG. 7 is a schematic view showing an example of the information recording medium of the present invention in which information is recorded by applying electric energy.

8 is a schematic diagram showing an example of a system using the information recording medium shown in FIG.

FIG. 9 is a partial cross-sectional view showing an example of a conventional information recording medium.

[Explanation of symbols]

1, 101, 201 substrate 2, 102 first dielectric layer 3, 103 first interface layer 4 recording layer 5, 105 second interface layer 6, 106 second dielectric layer 7 light absorption correction layer 8 reflection Layer 9 Adhesive Layer 10, 110 Dummy Substrate 12 Laser Light 13 First Recording Layer 14 First Reflection Layer 15 Third Dielectric Layer 16 Intermediate Layer 17 Fourth Dielectric Layer 18 Second Recording Layer 19 Fifth Dielectric layer 20 second reflective layer 21 first information layer 22 second information layer 23 groove surface 24 land surface 25, 26, 27, 28, 29, 30, 31, 207
Information recording medium 202 Lower electrode 203 Recording part 204 Upper electrode 205 Phase change part (recording layer) 206 Thermal insulation part (dielectric layer) 208 Pulse generating part 209 Resistance measuring instrument 210, 211 Switch 212 Applying part 213 Judging part 214 Electrical writing / Reading device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noboru Yamada             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D029 JA01 JB13 JB35 LA17                 5D121 AA04 EE03 EE09

Claims (18)

[Claims] 1. An information recording medium comprising a substrate and a recording layer, wherein the recording layer undergoes a phase transformation between a crystalline phase and an amorphous phase upon irradiation with light or application of electrical energy, and Zr , Zn, S and O containing Zr-Zn-S-
An information recording medium further including an O-based material layer. Wherein said Zr-Zn-S-O-based material layer has the formula (1): ## STR1 ## _{Zr B Zn C S D O 100} -BCD ( atomic%) ... (1) (wherein , B, C and D are 8 ≦ B ≦ 33 and 3 respectively.
The information recording medium according to claim 1, which is substantially in the range of ≤C≤30, C≤D≤2C <45, and 40≤B + C + D≤80. Wherein the Zr-Zn-S-O-based material layer further comprises Si, equation (2): ## STR2 ## _{Zr E Si F Zn G S H} O 100-EFGH ( atomic%) .. . (2) (wherein E, F, G, and H are each 1 ≦ E ≦ 3
0, 0 <F ≦ 23, 2 ≦ G ≦ 30, G ≦ H ≦ 2G <45
The information recording medium according to claim 1, wherein the information recording medium is substantially in the range of 40 ≦ E + F + G + H ≦ 80. 4. The Zr—Zn—S—O-based material layer has the formula (11): embedded image (ZrO ₂ ) _X (Zn—S) _100-X (mol%) ... (11) The information recording medium according to claim 2, consisting essentially of a material represented by the formula: wherein X is 50 ≦ X ≦ 80. 5. The Zr—Zn—S—O-based material layer containing Si has the formula (21): embedded image (ZrO ₂ ) _Y (SiO ₂ ) _Z (Zn—S) _100-Y—Z (Mol%) ... (21) (wherein Y and Z are respectively 20 ≦ Y ≦ 70, 10
The information recording medium according to claim 3, wherein the information recording medium is in the range of ≤Z≤50 and is substantially composed of a material represented by 50≤Y + Z≤80. 6. The material represented by the formula (21) is Zr.
O ₂ and SiO ₂ are contained in a substantially equal ratio, and the formula (22): (ZrSiO ₄ ) _A (Zn-S) _100-A (mol%) ... (22) (where A is , 33 ≦ A ≦ 67), the information recording medium according to claim 5. 7. The information recording medium according to claim 1, wherein the phase transformation occurs reversibly. 8. The recording layer is made of Ge-Sb-Te, Ge-S.
n-Sb-Te, Ge-Bi-Te, Ge-Sn-Bi
-Te, Ge-Sb-Bi-Te, Ge-Sn-Sb-
Bi-Te, Ag-In-Sb-Te and Sb-Te
The information recording medium according to claim 7, comprising any one material selected from the following. 9. The information recording medium according to claim 1, wherein the recording layer has a film thickness of 15 nm or less. 10. A recording medium comprising two or more recording layers.
10. The information recording medium according to any one of items 9 to 9. 11. A first dielectric layer, a recording layer, a second dielectric layer, and a reflective layer are formed in this order on one surface of a substrate, and the first dielectric layer and the first dielectric layer are formed. At least one of the two dielectric layers is
The information recording medium according to any one of claims 1 to 10, which is the Zr-Zn-S-O-based material layer and is in contact with the recording layer at an interface. 12. A reflective layer, a second dielectric layer, a recording layer, and a first dielectric layer are formed in this order on one surface of a substrate, and the first dielectric layer and the first dielectric layer are formed. 11. At least one of the two dielectric layers is the Zr—Zn—S—O-based material layer and is in contact with the recording layer at an interface. The information recording medium described in the item. 13. A Zr, Z including a substrate and a recording layer.
A method of manufacturing an information recording medium further including a Zr—Zn—S—O based material layer containing n, S and O, wherein the Zr—
A method of manufacturing an information recording medium, comprising a step of forming a Zn-S-O-based material layer by a sputtering method. 14. In the step of forming the Zr—Zn—S—O-based material layer by a sputtering method, formula (10): _{embedded image} Zr _b Zn _c S _d O _100-bcd (atomic%). . (10) (wherein b, c, and d are respectively 11 ≦ b ≦ 30,
5 ≦ c ≦ 27, c ≦ d ≦ 2c <40, and 40 ≦ b + c + d ≦ 80), wherein a sputtering target consisting essentially of a material is used. Recording medium manufacturing method. 15. A process of forming in the Zr-Zn-S-O-based material layer by sputtering, the formula (20): embedded image _{Zr e Si f Zn g S h} O 100-efgh ( atomic%) ... (20) (where e, f, g, and h are 3 ≦ e ≦ 2, respectively)
7, 1 <f ≦ 20, 5 ≦ g ≦ 27, g ≦ h ≦ 2g <40
And a sputtering target consisting essentially of a material represented by the formula: 40 ≦ e + f + g + h ≦ 80) is used to form the Zr—Zn—S—O-based material layer containing Si. 13. The method for manufacturing the information recording medium according to item 13. 16. In the step of forming the Zr—Zn—S—O-based material layer by a sputtering method, formula (11)
0): embedded image From the material represented by (ZrO ₂ ) _x (Zn-S) _100-x (mol%) ... (110) (where x is 50 ≦ x ≦ 80) The method of manufacturing an information recording medium according to claim 13, wherein the sputtering target substantially consists of the sputtering target. 17. In the step of forming the Zr—Zn—S—O-based material layer by a sputtering method, the formula (21)
0): embedded image (ZrO ₂ ) _y (SiO ₂ ) _z (Zn-S) _100-yz (mol%) ... (210) (wherein y and z are respectively 20 ≦ y ≦ 70 , And 10 ≦ z ≦ 50, and 50 ≦ y + z ≦
Zr-Zn-S containing Si using a sputtering target consisting essentially of a material represented by
The method for manufacturing an information recording medium according to claim 13, wherein an —O-based material layer is formed. 18. The material represented by the formula (210) is:
ZrO ₂ and SiO ₂ are contained in a substantially equal ratio, and the formula (22
0): embedded image (ZrSiO ₄ ) _a (Zn—S) _100-a (mol%) ... (220) (where a is in the range of 33 ≦ a ≦ 67) 18. The method for manufacturing an information recording medium according to claim 17, which is a material to be manufactured.