JP2000285515A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rewritable phase change optical recording medium less liable to suffer deterioration due to repetitive overwriting such as the degradation of jitter characteristics, the lowering of the signal amplitude and the occurrence of burst defects, excellent in shelf durability and ensuring good erasure characteristics even under recording conditions of high linear velocity and high density. SOLUTION: The optical recording medium has at least a recording layer and a reflecting layer successively laminated on a substrate in this order and can record, erase and reproduce information when the recording layer is irradiated with light. The recording and erasure of information are carried out by a phase change between amorphous and crystalline phases. A layer containing a substance obtained by combining an element M pertaining to the group IIIA to VIB of the 2nd to 6th period in the Periodic Table with nitrogen as an essential component is disposed in contact with the recording layer. The nitrogen content of the substance is less than the stoichiometric ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

As a material of the recording layer of these rewritable phase-change optical recording media, alloys such as Ge ₂ Sb ₂ Te ₅ (NY)
amada et al. Proc.Int.Symp.on Optical Memory 1987 p
61-66) are known. Such an optical recording medium having a Te alloy as a recording layer has a high crystallization speed and can perform high-speed overwriting with one circular beam only by modulating the irradiation power. In an optical recording medium using these recording layers, usually, a heat-resistant and light-transmitting dielectric layer is provided on each side of the recording layer to prevent deformation and opening of the recording layer during recording. I'm preventing. Further, a technique is known in which a metal reflective layer such as light reflective Al is laminated on the dielectric layer on the opposite side to the light beam incident direction to improve the signal contrast during reproduction by an optical interference effect. I have.

[0004] Problems in the above-mentioned conventional rewritable phase-change optical recording medium are as follows. That is,
In the conventional disk structure, the repetition of overwriting causes deterioration of jitter characteristics, deterioration of recording waveforms at the start and end ends of sector recording, and reduction of signal amplitude (contrast reduction). It is considered that this is caused by a change in the film thickness of the recording layer due to mass transfer of the recording layer, or a change in optical characteristics due to diffusion of a substance in the dielectric layer in contact with the recording layer into the recording layer. In addition, burst defects may occur due to crack growth in the protective layer.

In order to prevent a substance in a dielectric layer in contact with the recording layer from diffusing into the recording layer and causing a change in optical characteristics, a technique using Ge-N as a layer in contact with the recording layer (Ph)
ase-Change Optical Disk Having a Nitride Interface
Layer, N. Yamada et al. Jpn. J. Appl. Phys. Vol. 37
p2104-2110) is known. However, if the disk on which a signal is already recorded is left for a long period of time and overwritten (hereinafter referred to as an overwrite shelf), the erasing characteristics are reduced and the jitter characteristics are reduced. Of the recording layer and the layer adjacent to the recording layer, the recording / reproducing characteristics are significantly degraded after leaving for a long period of time. For this reason, there was a problem in the storage durability of the disk.

Further, ZnS and S are used as layers in contact with the recording layer.
A technique using a mixed layer of iO ₂ is generally widely known (T. Ohta et al, Proc. Int. Symp. on Optical Memory 19).
89 p49-50), but this technique had the same problem as above.

Further, as higher densities and higher speeds are demanded, higher densities and higher speeds are also being studied for phase-change optical recording media. Problems arise. This hinders stable recording and reproduction in mark length recording, and makes it difficult to achieve high density and high linear velocity.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Less deterioration due to repetitive overwriting, such as worse jitter characteristics, deterioration of the beginning and end of the sector, lowering of contrast, and occurrence of burst defects; second, excellent overwrite shelf characteristics and excellent long-term storage of recorded marks (Archival characteristics), thirdly, there is no delamination between layers after being left for a long time, and fourthly, erasure characteristics are good even under high linear velocity and high density recording conditions. An object of the present invention is to provide a possible phase change type optical recording medium.

[0009]

According to the present invention, information can be recorded, erased, and reproduced by irradiating a recording layer with light, and information recording and erasing can be performed between an amorphous phase and a crystalline phase. An optical recording medium in which at least a recording layer and a reflective layer are stacked in this order on a substrate by a phase change, and the second to sixth periods in the periodic table of the element are arranged so as to be in contact with the recording layer. Providing a layer containing, as an essential component, a substance in which an element M1 belonging to any of Group 3A to 6B and nitrogen are combined, and the nitrogen content in the substance is less than the stoichiometric ratio. It is a recording medium.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Deterioration due to repetitive overwriting, which is a problem to be solved by the present invention, that is, deterioration of jitter characteristics, deterioration of the beginning and end of a sector, and reduction of amplitude, are caused by mass transfer of a recording layer material, dielectric layer, It is thought to be due to the diffusion of sulfur in the recording layer. Further, the deterioration of the overwrite shelf characteristic is caused by the deterioration of the erasing characteristic. This may be because the state of the atomic arrangement or the like changes when the recording mark (amorphous layer) is left for a long time, or the dielectric layer reacts with the recording layer. Furthermore, in realizing high linear velocity and high density, it is considered that the problem of deterioration of the erasing characteristics is caused by a reduction in the time for which the recording layer is maintained at a temperature higher than the crystallization temperature. Can be

The present inventors have conducted intensive research,
A layer made of a substance in which nitrogen is combined with an element M1 belonging to Group 3A to Group 6B in the second to sixth periods in the periodic table of elements is provided in contact with the recording layer, and the element M1 in this layer is provided.
It has been found that by specifically changing the composition ratio of nitrogen and nitrogen, problems such as deterioration due to repeated overwriting, deterioration of overwrite shelf characteristics, and deterioration of erasing characteristics at high linear velocity and high density can be improved.

That is, a typical layer constitution of the constituent members of the optical recording medium of the present invention is as follows: a first dielectric layer on a transparent substrate;
It is obtained by laminating a layer composed of a substance obtained by combining nitrogen with the element M1 belonging to Group B, a recording layer, a second dielectric layer, and a reflective layer in this order. However, the present invention is not limited to this. For example, a layer made of a substance obtained by combining nitrogen and an element M2 belonging to Group 3A to Group 6B in the second to sixth periods in the periodic table of elements may be used as a second dielectric layer. Use instead of
It can be preferably used also as a layer between the second dielectric layer and the recording layer.

[0013] In the optical recording medium of the present invention, the nitrogen content in the layer composed of a substance obtained by combining nitrogen with the element M1 belonging to the groups 3A to 6B in the second to sixth periods in the periodic table of the element has a stoichiometric amount. It must be less than the ratio. Element M
It is preferable that the density of No. 1 is higher on the side closer to the recording layer. This has the following effects.

First, deterioration due to repeated overwriting can be improved by suppressing mass transfer of the recording layer and preventing diffusion of atoms from the dielectric layer to the recording layer. Second, the deterioration of the overwrite shelf characteristics can be improved. This is considered to be due to the effect of preventing the change of the atomic arrangement of the recording marks (amorphous) and the reaction between the dielectric layer and the recording layer even after being left for a long time. Third, it is possible to prevent separation between the recording layer and the layer in contact with the recording layer even after being left for a long time. this is,
From the second period to the sixth period in the periodic table of the elements in contact with the recording layer
This is considered to be caused by strengthening the bond with the recording layer by increasing the concentration of the element M at the layer interface made of a substance obtained by combining nitrogen with the element M1 belonging to the group 3A to group 6B of the period. Fourthly, the deterioration of the erasing characteristics under high linear velocity and high density recording conditions is improved. This is because the layer made of a substance in which nitrogen is combined with the element M1 belonging to Group 3A to Group 6B in the second to sixth periods in the periodic table of the element does not promote or hinder crystallization. It is considered that the crystallization can be performed.

As the element M1, different elements may be mixed and used, and chromium or germanium is preferable because it is excellent in the above-mentioned effects 1 to 4 and can be easily produced. Further, germanium is excellent in the above-mentioned effects 1 to 4, but is expensive, so that it is preferable to use it in combination with chromium from the viewpoint of economy.

Increasing the concentration of the element M1 at the interface between the element M1 belonging to the group 3A to the group 6B in the second to sixth periods in the periodic table of elements and the recording layer of the layer formed by combining nitrogen is not known. It is preferable because it has the effect of strengthening the bond with the layer and the effect of increasing the crystallization speed of the recording layer, but it is preferable to advance the combination with nitrogen in view of the thermal and chemical stability of the film. Therefore, in the concentration distribution of the element M and nitrogen in the film thickness direction, the concentration of the element M1 on the side in contact with the recording layer is increased, that is, the nitrogen concentration is decreased, and the concentration of the element M1 on the interface side opposite to the recording layer is decreased. It is important that the concentration is low, that is, the nitrogen concentration is high.

Further, in the present invention, particularly when chromium or germanium is used as the element M1, in order to obtain a high effect as described above, the number of atoms of chromium or germanium at the interface in contact with the recording layer is mr, and the number of atoms of nitrogen is nr, when the number of germanium atoms at the interface opposite to the recording layer is mo and the number of nitrogen atoms is no, 5 × mo / no>
It is preferable that mr / nr> mo / no. The ratio of the number of atoms of chromium or germanium, m, to the number of atoms of nitrogen, n, is preferably m> n from the viewpoint that peeling does not easily occur. Furthermore, 0.6m> n is more preferable from the viewpoint that a burst error hardly occurs during repeated recording. On the other hand, when 0.01 m> n, the overwrite characteristics deteriorate, which is not preferable.

The thickness of the layer made of a substance obtained by combining the element M1 and nitrogen is preferably 0.5 nm or more and 300 nm or less in consideration of the ease of obtaining a continuous film and optical conditions. From the viewpoint of recording characteristics, the thickness is more preferably 1 nm or more and 200 nm or less, and even more preferably 6 nm or more within this range in terms of productivity and ease of film formation.

The material of the first dielectric layer is preferably substantially transparent at the wavelength of the recording light, and has a refractive index larger than that of the transparent substrate and smaller than that of the recording layer. Specifically, a thin film of ZnS, Si, Ge,
Thin films of oxides of metals such as Ti, Zr, Ta, Nb,
A thin film of a nitride such as Si or Ge, a thin film of a nitride such as Zr or Hf, and a film of a mixture of these compounds are preferable because of high heat resistance. In particular, a film made of a mixture of ZnS and SiO ₂ is preferable because deterioration due to repeated overwriting hardly occurs. In particular, ZnS and SiO
The mixture of ₂ and carbon is preferable because the residual stress of the film is small, and the recording sensitivity, the carrier-to-noise ratio (C / N), the erasing rate, and the like are unlikely to be deteriorated even when recording and erasing are repeated. The thickness of the film is preferably from 10 to 500 nm from the viewpoint of optical conditions and productivity.

The recording layer of the present invention is not particularly limited, but may be a Ge—Te alloy, a Ge—Sb—Te alloy, a Pd—Ge—Sb—Te alloy, a Nb—Ge—Sb—
Te alloy, Pd-Nb-Ge-Sb-Te alloy, Pt-
Ge-Sb-Te alloy, Co-Ge-Sb-Te alloy,
In-Sb-Te alloy, Ag-In-Sb-Te alloy,
Ag-V-In-Sb-Te alloy, In-Se alloy, and the like. Because the record can be rewritten many times,
e-Sb-Te alloy, Pd-Ge-Sb-Te alloy, N
b-Ge-Sb-Te alloy, Pd-Nb-Ge-Sb-
Te alloys and Pt-Ge-Sb-Te alloys are preferred. In particular, Pd-Ge-Sb-Te alloy, Nb-Ge-Sb-
Te alloy, Pd-Nb-Ge-Sb-Te alloy, Pt-
Ge-Sb-Te alloys are preferable because they have a short erasing time and are excellent in recording many times.

The composition of the recording layer of the present invention is preferably represented by the following formula (I) in order to achieve both excellent overwrite shelf characteristics and excellent long-term storage characteristics (archival characteristics) of recording marks. In _{{(Ge 0.5 Te 0.5) x} (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y A z (I) formula, A is a Group 3A of the sixth period of the second period in the periodic table of the elements Represents elements other than Ge, Sb, and Te belonging to Group 6B, that is, Al, Si, Sc, Ti, V, and C
r, Mn, Fe, Co, Ni, Cu, Zn, Ga, G
e, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag,
Cd, In, Sn, La, Hf, Ta, W, Re, I
It represents at least one selected from r, Pt, Au, Tl, and Pb.

In the formula, x, y, and z each represent a number and satisfy the following relation. 0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.07, z = 0 or 0.2 ≦ x ≦ 0.8, 0 ≦ y ≦ 0.07, 0
<Z ≦ 0.2.

When x <0.2, the contrast becomes too small and a sufficient signal intensity may not be obtained.
In the case of 0.8, the crystallization speed becomes slow, the erasing characteristics are deteriorated, and direct overwriting may become difficult under the condition that the linear velocity is 5 m / s or more and the shortest mark length is 0.7 μm or less. When z = 0 and y <0.01, the stability of the amorphous is low, and the archival characteristics are poor.
If y> 0.07, overwriting after long-term storage may be difficult. When z> 0.2, the crystallization speed is reduced, the erasing characteristics are deteriorated, and it becomes difficult to perform direct overwriting or phase separation under the condition that the linear velocity is 5 m / s or more and the shortest mark length is 0.7 μm or less. In some cases, the repetition characteristics may be greatly deteriorated, or overwriting after long-term storage may be difficult. When z = 0, the stability of the amorphous may be low and the archival characteristics may be deteriorated.

A layer made of a substance in which nitrogen is combined with the element M1 belonging to Group 3A to Group 6B in the second to sixth periods in the periodic table of the element is provided so as to be in contact with the recording layer. When a layer made of a substance obtained by combining nitrogen and an element M2 belonging to Group 3A to Group 6B in the second to sixth periods is provided so as to be in contact with the recording layer, the crystallization speed of the recording layer becomes higher and the amorphous layer becomes amorphous. Since the stability characteristics change, the necessary composition range is preferably the range of the following formula (II). Here, M2 is selected from the same range of elements that can be used for M1.
May be the same as or different from M1. _{{(Ge 0.5 Te 0.5) x} (Sb 0.4 Te 0.6) 1-x} in _{1-yz Sb y A z (} II) ( wherein, A is the second period of the periodic Table 6
It represents an element other than Ge, Sb, and Te belonging to Group 3A to Group 6B of the period, x, y, and z represent numbers and satisfy the following relationship. 0.2 ≦ x ≦ 0.95, 0.02 ≦ y ≦ 0.07, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.07,
(0.001 ≦ z ≦ 0.2) When x <0.2, the contrast is too small, and a sufficient signal intensity may not be obtained. When x> 0.8, the crystallization speed is reduced. ,
The erasing characteristics are deteriorated, and direct overwriting may become difficult under the condition that the linear velocity is 5 m / s or more and the shortest mark length is 0.7 μm or less. When z = 0 and y <0.02, the stability of the amorphous is low, and the archival characteristics are poor. If y> 0.07, overwriting after long-term storage may be difficult. If z> 0.2,
The crystallization speed is reduced, the erasing characteristics are deteriorated, and the linear velocity is 5 m /
Under conditions of not less than s and the shortest mark length of 0.7 μm or less, direct overwriting may be difficult, repetition characteristics may be significantly deteriorated due to phase separation, overwriting after long-term storage may be difficult, and z ≦ In the case of 0.001, the stability of the amorphous is low, and the archival characteristics may be deteriorated.

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

The thickness of the recording layer of the present invention is preferably from 5 nm to 40 nm. When the thickness of the recording layer is thinner than the above, it is difficult to remarkably degrade the recording characteristics due to repeated overwriting, to increase the amplitude of the reproduction signal, or to increase the reproduction signal noise ratio. When the thickness of the recording layer is larger than the above, the recording layer is likely to move due to repeated overwriting, and the jitter is liable to deteriorate. In particular, when mark length recording is adopted, the recording layer is more likely to move due to recording and erasing than when pit position recording is used.To prevent this, it is necessary to further increase the cooling of the recording layer during recording. The thickness of the recording layer is more preferably from 10 nm to 35 nm, and is more preferably from 10 nm to 26 nm because of excellent recording characteristics such as a carrier-to-noise ratio (C / N) and an erasing ratio.

The material of the second dielectric layer of the present invention may be the same as the material of the first dielectric layer,
Different materials may be used. Thickness is 3nm or more and 50n
m or less is preferable. If the thickness of the second dielectric layer is smaller than the above, defects such as cracks and holes are generated, and the durability tends to decrease. If the thickness of the second dielectric layer is larger than the above, the recording layer becomes thicker. Tends to decrease the degree of cooling. Second
The thickness of the dielectric layer has a more direct effect on the cooling of the recording layer, and in order to obtain better erasing characteristics and repetitive durability, and particularly, in the case of mark length recording, good recording / erasing. In order to obtain the characteristics, a thickness of 30 nm or less is more effective. Since it absorbs light and can be efficiently used as thermal energy for recording and erasing, it is also preferable to be formed from a non-transparent material. For example, ZnS and Si
The mixture of O ₂ and carbon is preferable because the residual stress of the film is small, and the recording sensitivity, the carrier-to-noise ratio (C / N), the erasure rate, and the like are hardly deteriorated even when recording and erasing are repeated.

Examples of the material of the reflection layer include metals, alloys, and mixtures of metals and metal compounds having light reflectivity. Specifically, a metal having a high reflectivity, such as Al, Au, Ag, or Cu, an alloy containing the same as a main component, Al, S
Metal compounds such as nitrides, oxides, and chalcogenides such as i are preferable. Metals such as Al, Au, and Ag, and alloys containing these as main components are particularly preferable because of their high light reflectivity and high thermal conductivity. In particular, an alloy containing Al or Ag as a main component is preferable because the price of the material can be reduced. When Al is the main component, Ti, Cr, Ta, Hf, Z
An alloy to which at least one or more metals selected from r, Mn, and Pd are added in a total amount of 0.5 atomic% or more and 5 atomic% or less is preferable. Furthermore, since the corrosion resistance is good and hillocks and the like hardly occur, the total amount of the added elements is 0.1%.
Al-Hf-Pd alloy, Al-Hf alloy, Al-Ti alloy, Al-Ti-H containing 5 atom% or more and less than 5 atom%
f alloy, Al-Cr alloy, Al-Ta alloy, Al-Ti
It is preferable to be composed of any one of a -Cr alloy and an Al-Si-Mn alloy containing Al as a main component. These A
Among the alloys, Al- having the composition represented by the following formula:
Hf-Pd alloy has particularly excellent thermal stability,
By repeating recording and erasing many times, deterioration of the recording characteristics can be reduced. Pd _j Hf _k Al _1-jk 0.001 <j <0.01 0.005 <k <0.10 where j and k are the number of atoms of each element (the number of moles of each element)
Represents

The thickness of the above-mentioned reflective layer is approximately 10 nm or more and 300 nm in any case made of any alloy.
Hereinafter, it is more preferable to set the thickness to 30 to 200 nm.

As the material of the substrate of the present invention, various transparent synthetic resins, transparent glass and the like can be used. In order to avoid the influence of dust and scratches on the substrate, it is preferable to use a transparent substrate and perform recording from the substrate side with a focused light beam.As such a transparent substrate material, glass, polycarbonate, polymethyl methacrylate, Polyolefin resin, epoxy resin, polyimide resin and the like can be mentioned. In particular, a polycarbonate resin having a small optical birefringence, a small hygroscopicity, and easy molding,
Amorphous polyolefin resins are preferred.

The thickness of the substrate is not particularly limited, but is practically 0.01 mm to 5 mm.
If it is less than 0.01 mm, even when recording with a light beam focused from the substrate side, it is easily affected by dust and becomes 5 mm
In the case of exceeding, it becomes difficult to increase the numerical aperture of the objective lens, and the spot size of the irradiation light beam becomes large, so that it becomes difficult to increase the recording density.

The substrate may be flexible or rigid. The flexible substrate is used in the form of a tape, a sheet, or a card. The rigid substrate is used in the form of a card or a disk. In addition, these substrates, after forming the recording layer and the like,
By using two substrates, an air sandwich structure, an air incident structure, or a close bonding structure may be employed.

As a light source used for recording on the optical recording medium of the present invention, a high-intensity light source such as a laser beam or a strobe light can be mentioned. In particular, a semiconductor laser beam can be reduced in size and power consumption. This is preferable because the modulation is easy.

The recording is performed by irradiating a laser beam pulse or the like to the crystalline recording layer to form an amorphous recording mark. Alternatively, a recording mark in a crystalline state may be formed on a recording layer in an amorphous state. Erasing can be performed by irradiating a laser beam to crystallize an amorphous recording mark or to make a crystalline recording mark amorphous. Since the recording speed can be increased and the recording layer is hardly deformed, it is preferable to form an amorphous recording mark during recording and crystallize during erasing. In addition, the light intensity is high at the time of forming a recording mark and slightly weakened at the time of erasing, and rewriting is performed by one light beam irradiation.
Beam overwriting is preferable because the time required for rewriting is reduced.

Next, a method for manufacturing the optical recording medium of the present invention will be described. A first dielectric layer, a layer made of a compound of chromium or germanium and nitrogen, a recording layer, a second dielectric layer,
Examples of a method for forming a reflective layer on a substrate include a method of forming a thin film in a vacuum, such as a vacuum deposition method, an ion plating method, and a sputtering method. Especially the composition,
The sputtering method is preferred because the film thickness can be easily controlled. Reactive sputtering for reacting a target with a gas introduced into a vacuum chamber can be preferably used because composition control in the layer thickness direction can be easily performed. In reactive sputtering, when a layer is formed by reacting with a nitrogen gas using a germanium target or a chromium target, the nitrogen partial pressure in the vacuum chamber and the power input to the target must be changed over time during film deposition. It is possible to change the ratio of chromium or germanium to nitrogen in the film thickness direction by a method or a high-speed deposition method that effectively changes the amount of reaction with nitrogen on the film growth surface while keeping these constant. it can. In the case where a film is formed using a germanium target or a chromium target, a DC power supply that can be lower than in the case of using a high-frequency power supply can be used because the target has conductivity. The thickness of the recording layer or the like to be formed can be easily controlled by monitoring the deposited state with a quartz crystal film thickness meter or the like.

Further, in not significantly impaired range the effects of the present invention, after forming the reflective layer, flaws, such as for prevention of deformation, ZnS, dielectric layers or ultraviolet, such as SiO _2, ZnS and mixtures SiO ₂ A protective layer such as a cured resin may be provided as necessary.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (Analysis and measurement method) The composition of the reflective layer and the recording layer was determined by ICP emission spectrometry (SPS4000, manufactured by Seiko Instruments Inc.).
Confirmed by The composition distribution in the layer thickness direction of the layer made of a compound of chromium or germanium and nitrogen was examined by X-ray photoelectron spectroscopy (SSX-100, manufactured by SSI). The film thickness during the formation of the recording layer, the dielectric layer, and the reflective layer was monitored with a quartz crystal film thickness meter. The thickness of each layer is
It was measured by observing the cross section with a scanning or transmission electron microscope.

In the optical recording medium formed by sputtering, the recording layer on the entire surface of the disk was crystallized and initialized with a beam of a semiconductor laser having a wavelength of 830 nm before recording. Next, under the condition that the recording track has a linear velocity of 6 m / sec, the numerical aperture of the objective lens is 0.6 and the wavelength of the semiconductor laser is 6
Using an optical disk evaluation device having a 60 nm optical head, an 8/16 modulation random pattern was overwritten 10,000 times by mark length recording. At this time, a multi-pulse was used as the recording laser waveform. The window width at this time was 34 ns (the shortest mark length in this case was 0.63 μm). Recording power and erasing power were optimized for each disk.

Jitter was measured by a time interval analyzer. The decrease in the amplitude of the signal waveform and the presence or absence of a burst defect were observed with an oscilloscope.

Example 1 A polycarbonate substrate having a guide groove with a thickness of 0.6 mm, a diameter of 12 cm, and a pitch of 1.48 μm (a land width of 0.74 μm and a groove width of 0,4 mm) was rotated at 30 revolutions per minute. 74 μm), the following sputtering film formation was performed. First, 1 ×
After evacuation to 10 ⁻³ Pa, ZnS to which 20 mol% of SiO ₂ was added was sputtered in an Ar gas atmosphere of 2 × 10 ⁻¹ Pa to form a first dielectric layer with a thickness of 95 nm on the substrate. Next, chromium was sputtered in an Ar gas atmosphere containing 50% of N ₂ gas to form a layer of chromium and nitrogen having a thickness of 2 nm. Subsequently, an alloy target made of Ge, Sb, and Te is sputtered under the same conditions as those of the first dielectric layer, and a composition Ge _17.1 Sb _27.6 Te _55.3 having a thickness of 19 nm is used.
[That is, ｛(Ge _0.5 Te _0.5 ) _0.349 (Sb _0.4 Te
_0.6 ) _0.651 { _0.979 Sb _0.021 ]. Further, as the second dielectric layer, the same ZnS.SiO as the first dielectric layer is used.
₂ was 15nm formed, to form a reflective layer having a thickness of 110nm by sputtering _A l97.5 Cr _2.5 alloy thereon. After removing the disk from the vacuum container, an acrylic UV-curable resin (SD-Nippon Ink Co., Ltd.) was placed on the reflective layer.
101) is spin-coated and cured by irradiation with ultraviolet rays to form a resin layer having a thickness of 3 μm. Then, a slow-acting ultraviolet-effect resin is applied using a screen printing machine, and after irradiation with ultraviolet rays, the resin is similarly irradiated. The two prepared disks were bonded to obtain an optical recording medium of the present invention.

Examination of the composition distribution in the thickness direction of the layer composed of chromium and nitrogen of this disk revealed that the atomic composition ratio of chromium and nitrogen was 8: 2 near the interface of the recording layer, and that the atomic composition ratio of chromium and nitrogen was near the interface of the first dielectric layer. 8: 3.

When the jitter after 10,000 times of overwriting was measured, it was 3.06 ns, which was confirmed to be 9% of the window width and sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was measured to be 2.5 × 10 ⁻⁵ . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours.
Thereafter, when the byte error rate of the same portion was measured, there was almost no change of 3.0 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 4.1 × 10 ⁻⁵ and hardly changed. The jitter at this time was 3.42 ns, which was a good value of 10% of the window width. It was also visually confirmed that delamination did not occur.

(Comparative Example 1) Instead of sputtering in an Ar gas atmosphere in which chromium is mixed with 50% of N ₂ gas,
A disk was produced in the same manner as in Example 1 except that N was sputtered with Ar gas. The composition ratio of the chromium and nitrogen layer of this disk is approximately 1: 1 for chromium and nitrogen,
The composition distribution in the thickness direction was constant. When the disk was left in the air at 80 ° C. for 100 hours, delamination was observed.

(Example 2) A disk was produced in the same manner as in Example 1 except that the thickness of the layer produced by sputtering chromium was changed to 10 nm. When the jitter after 10,000 times of overwriting was measured, it was 3.16 ns, which was confirmed to be 9.3% of the window width and sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed.

Further, recording was performed once on this disk, and the byte error rate at that time was measured.
It was 0 ^-5 . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. After that, when the byte error rate of the same portion was measured, it was 3.3 × 10 ⁻⁵ and there was almost no change. Furthermore, when this portion was overwritten once, the byte error rate was 4.8 × 1
That there is little change between 0 ^-5 it could be confirmed. The jitter at this time was 3.57 ns, which was a good value of 10.5% of the window width. It was also visually confirmed that delamination did not occur. Examination of the composition distribution in the thickness direction of the layer composed of chromium and nitrogen revealed that the atomic composition ratio of chromium and nitrogen was 8: 2 near the interface of the recording layer and 8: 3 near the interface of the first dielectric layer. .

Example 3 A disk was produced in the same manner as in Example 1 except that the thickness of the layer formed by sputtering chromium was changed to 20 nm. When the jitter after 10,000 times of overwriting was measured, it was 3.19 ns, which was 9.4% of the window width, which was confirmed to be sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed.

Further, recording was performed once on this disk, and the byte error rate at that time was measured.
It was 0 ^-5 . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. After that, when the byte error rate of the same portion was measured, it was almost unchanged at 3.5 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, the byte error rate was 4.8 × 1
That there is little change between 0 ^-5 it could be confirmed. The jitter at this time was a good value of 3.67 ns, 10.8% of the window width. It was also visually confirmed that delamination did not occur. Examination of the composition distribution in the thickness direction of the layer composed of chromium and nitrogen on this disk revealed that the atomic composition ratio of chromium and nitrogen was 8: 3.5 near the interface of the recording layer and 8 near the interface of the first dielectric layer. : 3.

Example 4 A disk was manufactured in substantially the same manner as in Example 1 except that a layer was formed using germanium instead of chromium. When the jitter after 10,000 times of overwriting was measured, it was 3.03 ns, which was 8.9% of the window width, which was confirmed to be sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed.

The recording was performed once on this disk, and the byte error rate at that time was measured.
It was 0 ^-5 . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. After that, when the byte error rate of the same portion was measured, it was 2.3 × 10 ⁻⁵ and there was no change. Further, when this portion was overwritten once, it was confirmed that the byte error rate was 4.3 × 10 ^-5 and hardly changed. The jitter at this time was 3.33 ns, which was a good value of 9.8% of the window width. It was also visually confirmed that delamination did not occur. Examination of the composition distribution in the thickness direction of the layer made of germanium and nitrogen in this disk revealed that the atomic composition ratio of germanium to nitrogen was 7: 2 near the interface of the recording layer and 7: 3 near the interface of the protective layer. .

Example 5 A disk was manufactured in the same manner as in Example 4 except that the thickness of the layer formed by sputtering germanium was changed to 8 nm. When the jitter after 10,000 times of overwriting was measured, it was confirmed that it was 2.99 ns, which is 8.8% of the window width, which is sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed.

Further, recording was performed once on this disk, and the byte error rate at that time was measured.
It was 0 ^-5 . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. Thereafter, when the byte error rate of the same portion was measured, there was no change of 2.4 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 4.1 × 10 ⁻⁵ and hardly changed. The jitter at this time was 3.34 ns, a good value of 9.8% of the window width. It was also visually confirmed that delamination did not occur. Examination of the composition distribution in the thickness direction of the layer made of germanium and nitrogen in this disk revealed that the atomic composition ratio of germanium and nitrogen was 7: 2 near the interface of the recording layer and 7: 3 near the interface of the first dielectric layer. Met.

Example 6 A polycarbonate substrate with a guide groove having a thickness of 0.6 mm, a diameter of 12 cm and a pitch of 1.48 μm (land width 0.74 μm, groove width 0. 74 μm), the following sputtering film formation was performed. First, 1 ×
After evacuation to 10 ⁻³ Pa, ZnS to which 20 mol% of SiO ₂ was added was sputtered in an Ar gas atmosphere of 2 × 10 ⁻¹ Pa to form a first dielectric layer with a thickness of 95 nm on the substrate. Next, a germanium target on which chromium pellets were placed was sputtered in an Ar gas atmosphere mixed with 40% of N ₂ gas to form a layer of germanium, chromium, and nitrogen having a thickness of 8 nm. Subsequently, under the same conditions as those for the first dielectric layer, an alloy target made of Ge, Sb, and Te is sputtered to form a composition Ge _17.1 Sb _27.6 Te having a thickness of 19 nm.
A recording layer of _55.3 was obtained. Furthermore the same ZnS · SiO ₂ and the first dielectric layer was 15nm formed as a second dielectric layer, a film thickness 110nm by sputtering _A l97.5 Cr _2.5 alloy on the
Was formed. After removing the disk from the vacuum container, an acrylic UV-curable resin (SD-101 manufactured by Dainippon Ink and Chemicals Co., Ltd.) is spin-coated on the reflective layer, and cured by UV irradiation to form a resin layer having a thickness of 3 μm. Then, a slow-acting ultraviolet light effect resin was applied using a screen printing machine, and after irradiating with ultraviolet light, two discs produced in the same manner were adhered to obtain an optical recording medium of the present invention.

When the jitter after 10,000 times of overwriting was measured, it was confirmed that it was 3.06 ns, 9% of the window width, which is sufficiently small for practical use. The amplitude of the signal hardly changes compared to the amplitude of the signal after overwriting 10 times,
No burst defects were seen.

Further, recording was performed once on this disk, and the byte error rate at that time was measured.
It was 0 ^-5 . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. After that, when the byte error rate of the same portion was measured, it was 2.3 × 10 ⁻⁵ and there was no change. Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 4.0 × 10 ⁻⁵ and hardly changed. The jitter at this time was 3.39 ns, which was a good value of 10% of the window width. It was also visually confirmed that delamination did not occur.

When the composition distribution in the thickness direction of the layer made of germanium, chromium and nitrogen of this disk was examined, the atomic composition ratio of germanium, chromium and nitrogen was 20: 5: 3 near the interface of the recording layer, and the first 20 near the dielectric layer interface:
5: 5.

Example 7 The composition of the recording layer was Ge _19.1 Sb
_26.9 Te _54.0 [that is, ｛(Ge _0.5 Te _0.5 )
Except that the _{0. 396 (Sb 0.4 Te 0.6)} 0.604} 0.964 Sb 0.036] in the same manner as in Example 6 to prepare a disk were evaluated in recording characteristics, it gives almost the same results as in Example 6 Was.

Example 8 The composition of the recording layer was Ge _21.0 Sb
_25.2 Te _53.8 [that is, ｛(Ge _0.5 Te _0.5 )
Except that the _{0. 434 (Sb 0.4 Te 0.6)} 0.566} 0.967 Sb 0.033] in the same manner as in Example 6 to prepare a disk were evaluated in recording characteristics, it gives almost the same results as in Example 6 Was.

Example 9 The composition of the recording layer was Ge _15.5 Sb
_28.8 Te _55.7 [that is, ｛(Ge _0.5 Te _0.5 )
Except that the _{0. 316 (Sb 0.4 Te 0.6)} 0.684} 0.980 Sb 0.020] in the same manner as in Example 6 to prepare a disk were evaluated in recording characteristics, it gives almost the same results as in Example 6 Was.

Example 10 The composition of the recording layer was Ge _18.0 S
b _26.8 Te _54.8 Nb _0.4 [ie [｛(Ge _0.5 Te
_0.5 ) _0.371 (Sb _0.4 Te _0.6 ) _0.629 ｝ _0.973 Sb _0.023
Nb _0.004 ], a disc was prepared in the same manner as in Example 6, and the recording characteristics were evaluated.
Almost the same result was obtained.

(Example 11) The composition of the recording layer was Ge _18.0 S
b _26.2 Te _55.4 Ag _0.006 [ie [｛(Ge _0.5 Te
_0.5 ) _0.366 (Sb _0.4 Te _0.6 ) _0.634 ｝ _0.978 Sb _0.016
Ag _0.006 ], and a disk was produced in the same manner as in Example 6 and the recording characteristics were evaluated.
Almost the same result was obtained.

Example 12 A disk was prepared in the same manner as in Example 1 except that layers were formed using aluminum, titanium and zirconium instead of chromium in Example 1, and the same evaluation of recording characteristics was performed. Was performed, the result almost similar to that of Example 1 was obtained. That is, when the jitter after 10,000 times of overwriting was measured, it was confirmed that all the disks were 9% of the window width and sufficiently small for practical use. In addition, the signal amplitudes of all the disks hardly changed compared to the signal amplitudes after overwriting 10 times, and no burst defects were observed. Recording was performed once on these disks, and the byte error rate at that time was measured.
× 10 ^-5 , 2.8 × 10 ^-5 , 2.9 × 10 ^-5 .

Example 13 A polycarbonate substrate with a guide groove having a thickness of 0.6 mm, a diameter of 12 cm and a pitch of 1.48 μm (a land width of 0.74 μm and a groove width of 0.2 mm) was rotated at 30 revolutions per minute. 74 μm), the following sputtering film formation was performed. First, 1 ×
After evacuation to 10 ⁻³ Pa, ZnS to which 20 mol% of SiO ₂ was added was sputtered in an Ar gas atmosphere of 2 × 10 ⁻¹ Pa to form a first dielectric layer with a thickness of 93 nm on the substrate. Next, a chromium target was sputtered with a mixed gas of 50% nitrogen and 50% argon to form a layer having a thickness of 2 nm. Subsequently, an alloy target composed of Ge, Sb, and Te is sputtered to obtain a composition Ge _33.9 Sb ₁₅ having a thickness of 19 nm.
_.6 Te _50.5 [ie ｛(Ge _0.5 Te _0.5 ) _0.710 (S
b _0.4 Te _{0.6) 0.290}} to obtain a recording layer of _{0. 955} Sb _0.045]. Further, a chromium target was sputtered with a mixed gas of 40% of nitrogen and 60% of argon to form a layer having a thickness of 2 nm. Subsequently, the same ZnS.SiO ₂ as that of the first dielectric layer was formed to a thickness of 13 nm as a second dielectric layer, and Al _97.5 was formed _thereon.
To form a reflective layer having a thickness of 110nm by sputtering cr _2.5 alloy. After removing this disk from the vacuum container,
An acrylic ultraviolet curable resin (SD-101, manufactured by Dainippon Ink and Chemicals, Inc.) is spin-coated on the reflective layer and cured by irradiation with ultraviolet light to form a resin layer having a thickness of 3 μm, and then using a screen printer. After applying a slow-acting ultraviolet light effect resin and irradiating with ultraviolet light, two discs produced in the same manner were bonded to obtain an optical recording medium of the present invention.

Recording was performed once on this disk, and the byte error rate at that time was 3.9 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, there was almost no change of 4.8 × 10 ⁻⁵ . Further, when this portion was overwritten once, it was confirmed that the byte error rate was 2.0 × 10 ⁻⁴ and there was no practical problem. The jitter at this time was 3.4 ns, which was a favorable value of 10.0% of the window width.

Example 14 The composition of the recording layer was Ge _34.1 S
b _15.3 Te _50.6 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 706
(Sb _0.4 Te _0.6 ) A disk having a six-layer structure was produced in the same manner as in Example 13, except that _0.294 { _0.980 Sb _0.035 ].

Recording was performed once on this disk, and the byte error rate at that time was measured to be 6.8 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was 1.3 × 10 ⁻⁴ and there was almost no change. Further, when this portion was overwritten once, it was confirmed that the byte error rate was 4.9 × 10 ⁻⁴ and there was no practical problem. The jitter at this time was 3.6 ns, a favorable value of 10.6% of the window width.

(Example 15) The composition of the recording layer was Ge _36.2 S
b _13.0 Te _50.8 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 747
(Sb _0.4 Te _0.6 ) A disk having a six-layer structure was manufactured in the same manner as in Example 13, except that _0.253 ｝ _0.968 Sb _0.032 ].

Recording was performed once on this disk, and the byte error rate at that time was 2.9 × 10 ⁻⁴ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
After that, when the byte error rate of the same portion was measured, it was confirmed that there was no practical problem of 4.9 × 10 ⁻⁴ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 4.4 × 10 ⁻⁴ and there was no practical problem. The jitter at this time is 4.0 ns
And 11.8% of the window width.

Example 16 The composition of the recording layer was Ge _39.6 S
b _10.2 Te _50.2 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 818
(Sb _0.4 Te _0.6 ) A disk having a six-layer structure was produced in the same manner as in Example 13, except that _0.182 ｝ _0.969 Sb _0.031 ].

Recording was performed once on this disk, and the byte error rate at that time was 1.5 × 10 ⁻³ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, it was 1.9 × 10 ⁻³ . Furthermore, when this part is overwritten once, the byte error rate becomes
The error rate was not deteriorated before and after overwriting to 2.2 × 10 ⁻³ . The jitter at this time is 4.3
ns, which was 12.6% of the window width.

Example 17 The composition of the recording layer was Ge _27.0 S
b _20.0 Te _53.0 [i.e. _{{(Ge 0.5 Te 0.5) 0.} 555
(Sb _0.4 Te _0.6 ) A disk having a six-layer structure was produced in the same manner as in Example 13, except that _0.445 { _0.973 Sb _0.027 ].

Recording was performed once on this disk, and the byte error rate at that time was 2.9 × 10 ⁻⁵ . In a state where the humidity was not adjusted such as humidification, the sample was left for 100 hours at 80 ° C. in the recorded state.
Thereafter, when the byte error rate of the same portion was measured, a slight increase of 4.1 × 10 ⁻⁴ was observed. further,
When this portion was overwritten once, the byte error rate was 6.7 × 10 ^-5, and the error rate did not deteriorate before and after overwriting. The jitter at this time was 3.2 ns, which was 9.4% of the window width. (Example 18) the composition of the recording layer Ge ₂ Sb ₂ Te ₅ [i.e. _{(Ge 0.5 Te 0.5) 0.444 (} Sb 0. 4 T
e _0.6 ) _0.556 ], and a six-layer disc was obtained in the same manner as in Example 13.

Recording was performed once on this disk, and the byte error rate at that time was 3.0 × 10 ⁻⁵ . The recording was left for 20 hours at 80 ° C. and 80% relative humidity. Thereafter, when the byte error rate of the same portion was measured, it was 2 × 10 ^-2 . Observation of the playback waveform shows that the amplitude has decreased,
It was presumed that part of the amorphous part was crystallized.

The composition of the recording layer was Ge ₁ Sb ₂ Te
₄ [ie (Ge _0.5 Te _0.5 ) _0.287 (Sb _0.4 T
e _0.6 ) _0.714 ], the byte error rate is 4.1 when left at 80 ° C. and a relative humidity of 80% for 20 hours.
It changed from × 10 ⁻⁴ to 8 × 10 ⁻² . (Example 19) the composition of the recording layer Ge _0.5 Te _0.5 [i.e. _{{(Ge 0.5 Te 0.5) 1.00} (Sb 0. 4 Te 0.6) 0.00}
_1.00 Sb _0.00 ], and a six-layer disc was produced in the same manner as in Example 13.

Recording was performed once on this disk, and the byte error rate at that time was 2 × 10 ⁻² .

(Embodiment 20) Rotation at 30 revolutions per minute
0.6mm thick, 12cm in diameter, 1.48μm
Board with landed guide grooves (land width
0.74 μm, groove width 0.74 μm)
Sputter deposition was performed. First, 1 ×
10^-3After exhausting to Pa, 2 × 10^-1Ar gas of Pa
SiO in zero atmosphere_Two ZnS with 20 mol% added
Putting to form a first dielectric layer with a thickness of 95 nm on the substrate
did. Then N_TwoAr gas atmosphere containing 8.2% gas
Titanium is sputtered in TiN_0.87Layers
Formed. Subsequently, under the same conditions as for the first dielectric layer, G
sputters an alloy target consisting of e, Sb, Te
And a composition Ge having a thickness of 19 nm_17.1Sb_27.6Te_55.3Note
The recording layer was obtained. Furthermore, a first dielectric layer as a second dielectric layer
Same ZnS-SiO_TwoIs formed to a thickness of 15 nm, and Al is formed thereon.
_97.5Cr_2.5Sputtering alloy to reflect 110nm film
A layer was formed. This disk was taken out of the vacuum container
Then, on this reflective layer, acrylic UV curable resin (Dainippon
Ink Co., Ltd. SD-101) is spin-coated and ultraviolet
Cured by radiation to form a 3 μm thick resin layer,
Next, use a screen printing machine to apply the delayed UV effect
After applying the resin and irradiating it with ultraviolet light, the
Two disks were bonded to obtain an optical recording medium of the present invention.

When the jitter after 10,000 times of overwriting was measured, it was 3.02 ns, which was 8.9 of the window width.
%, Which was sufficiently small for practical use. The amplitude of the signal is 1
There was almost no change compared to the amplitude of the signal after 0 overwrites, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was measured to be 1.5 × 10 ⁻⁵ . While keeping the recorded state, it was left in the air at 80 ° C. for 100 hours. Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 2.5 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, it was confirmed that the byte error rate was 3.1 × 10 ^-5 and hardly changed. The jitter at this time is 3.38 ns
And 9.9% of the window width, which was a good value. It was also visually confirmed that delamination did not occur.

Further, a disk provided with a second boundary layer of TiN _0.87 having a thickness of 2 nm between the recording layer and the second dielectric layer was manufactured, and the recording characteristics were evaluated. When the jitter after 10,000 times of overwriting was measured, it was 2.95 ns, which was 8.7% of the window width, which was confirmed to be sufficiently small for practical use. The amplitude of the signal hardly changed compared to the amplitude of the signal after 10 times of overwriting, and no burst defect was observed. Further, recording was performed once on this disk, and the byte error rate at that time was 1.3 × 10 ⁻⁵ . 90 ° C, relative humidity 80% ° C as recorded
Was left for 100 hours. Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 1.5 × 10 ⁻⁵ . Furthermore, when this portion was overwritten once, the byte error rate was 1.9 ×
It was confirmed that there was almost no change at 10 ^-5 . The jitter at this time was 3.11 ns, a good value of 9.2% of the window width. It was also visually confirmed that delamination did not occur. Example 21 Instead of sputtering titanium in an Ar gas atmosphere containing 8.2% N ₂ gas, titanium was sputtered in an Ar gas atmosphere containing 4.8% N ₂ gas to have a thickness of 2 nm. A disc was produced in the same manner as in Example 20 except that the TiN 0.45 layer was formed. Recording was performed once on this disk, and the byte error rate at that time was 1.8 × 10 ⁻⁵ . The recording was left for 100 hours at 90 ° C. and 80% relative humidity. Thereafter, when the byte error rate of the same portion was measured, it was almost unchanged at 2.1 × 10 ⁻⁵ . When this portion was overwritten once, the byte error rate was 6.3 × 10 ^-2 . It was also visually confirmed that delamination did not occur. (Comparative Example 2) A disc was produced in the same manner as in Example 1 except that TiN was sputtered with Ar gas instead of Ti in an Ar gas atmosphere containing 8.2% of N ₂ gas. The composition ratio of the layer composed of titanium and nitrogen in this disk was approximately 1: 1 for titanium and nitrogen, and the composition distribution in the thickness direction was constant. Put this disk in the air, 8
When left at 0 ° C. for 100 hours, delamination was observed.

[0078]

According to the present invention, an optical recording medium having good recording characteristics at the initial stage and after long-term storage can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 EA04 EA12 EA14 EA23 EA31 EA36 EA40 FA01 FA11 FA12 FA21 FA25 FA27 FA28 FB04 FB05 FB08 FB09 FB12 FB16 FB20 FB22 FB30 5D029 JA01 JB45 NA07

Claims (9)

[Claims] An information recording, erasing, and reproducing operation can be performed by irradiating a recording layer with light, and information recording and erasing are performed by a phase change between an amorphous phase and a crystalline phase. An optical recording medium in which at least a recording layer and a reflective layer are laminated in this order, and any one of a 3A group to a 6B group of the second to sixth periods in the Periodic Table of the Elements so as to be in contact with the recording layer. 1. An optical recording medium, comprising: a layer containing, as an essential component, a substance obtained by combining an element M1 belonging to genus and nitrogen as an essential component, wherein the nitrogen content in the substance is less than the stoichiometric ratio. Wherein the recording layer is represented by the following formula _{(I) {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y A z (I) ( wherein, A is periodic From the second period to the sixth in the law table
It represents an element other than Ge, Sb, and Te belonging to Group 3A to Group 6B of the period, x, y, and z represent numbers and satisfy the following relationship. 0.2 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.07, z = 0 or 0.2 ≦ x ≦ 0.8, 0 ≦ y ≦ 0.07, 0
2. The optical recording medium according to claim 1, wherein the recording medium is used for recording a mark length of 0.7 [mu] m or less at a linear velocity of 5 m / s or more at a linear velocity of 5 m / s or more. 3. The optical recording medium according to claim 1, wherein the composition ratio between the element M1 and nitrogen is not uniform, and the concentration of the element M is higher on the side closer to the recording layer. 4. The optical recording medium according to claim 3, wherein the element M1 is chromium or germanium. 5. The number m of atoms of chromium or germanium.
The optical recording medium according to claim 4, wherein the number n of atoms of nitrogen and nitrogen is m> n. 6. The optical recording medium according to claim 4, wherein a layer made of a substance obtained by combining chromium or germanium and nitrogen is provided between the substrate and the recording layer. 7. The optical recording medium according to claim 1, wherein a dielectric layer containing ZnS and SiO ₂ is provided between at least one of the substrate and the recording layer and between the recording layer and the reflection layer. 8. The optical recording medium according to claim 1, wherein the average layer thickness of the layer made of a substance in which the element M1 and nitrogen are combined is 0.5 nm or more and 300 nm or less. 9. A layer, a recording layer, and a layer in contact with a recording layer, wherein at least the element M1 in contact with the recording layer and nitrogen are combined on the substrate and the nitrogen content is less than the stoichiometric ratio. An optical recording medium comprising a layer in which the element M2 is combined with nitrogen and the nitrogen content is less than the stoichiometric ratio, wherein M1 and M2 are the first and second elements in the periodic table. An element belonging to any one of groups 3A to 6B in the second to sixth periods, wherein the recording layer has the following formula (I)
_{I), {(Ge 0.5 Te} 0.5) x (Sb 0.4 Te 0.6) 1-x} 1-yz Sb y A z (II) ( In the formula, A, sixth from the second period in the periodic table of the elements
It represents an element other than Ge, Sb, and Te belonging to Group 3A to Group 6B of the period, x, y, and z represent numbers and satisfy the following relationship. 0.2 ≦ x ≦ 0.95, 0.02 ≦ y ≦ 0.07, z =
0 or 0.2 ≦ x ≦ 0.95, 0 ≦ y ≦ 0.07,
2. The optical recording medium according to claim 1, wherein the optical recording medium comprises: 0.001 ≦ z ≦ 0.2).