JP2000173104A - Optical recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recording medium having high C/N and overwriting erasing rate and excellent adhesion property. SOLUTION: This medium is produced by forming a first transparent dielectric material layer 12 of ZnS-SiO2 having about 1000 Åfilm thickness, an intermediate layer 13 essentially comprising SiC having about 200 Å film thickness, a recording layer 14 of Ge2Sb2Te5 having about 400 Å film thickness, a second transparent dielectric layer 15 of ZnS-SiO2 having about 300 Åfilm thickness, and a reflection layer 16 of Al having about 1000 Å film thickness on the principal plane of a polycarbonate 3.5-inch diameter disk transparent substrate 11 by magnetron sputtering successively. In this process, after the intermediate layer 13 is formed, the layer is subjected to bombard treatment in an oxygen atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording layer having a phase change between an amorphous state and a crystalline state according to the output of a light beam such as a laser beam to be irradiated. The present invention relates to a rewritable optical recording medium which records and reproduces digital information by utilizing a difference in reflectance of the optical recording medium.

[0002]

2. Description of the Related Art FIG. 1 is a partial sectional view of a conventional rewritable optical recording medium M utilizing a phase transition (hereinafter referred to as a medium M). In the figure, 1 is a disk-shaped transparent substrate made of resin such as polycarbonate, glass or the like, and 2 is Zn
The first transparent dielectric layer made of S-SiO ₂ or the like, 3 GeT
e, a recording layer which can be changed into two states of amorphous and crystalline, 4 is a second transparent dielectric layer made of ZnS-SiO ₂ or the like, 5 is a reflective layer made of a high reflectivity material such as Al. It is.

In such a rewritable medium M, the recording layer 3 has a different light reflectance between the crystalline state and the non-crystalline state. Generally, the crystalline state has a higher reflectance. . The operating principle of the medium M is as follows. First, all the recording pits of the recording layer 3 are crystallized. That is, initialization is performed in a state where the reflectance is high.
For writing information, a laser beam pulse-modulated to two types of laser power is irradiated while rotating the medium M, and a recording layer is formed in a recording pit irradiated with a high-power (about 10 to 20 mW) laser beam. The material becomes higher than the melting points of the three materials, and is melted and rapidly cooled to become amorphous. On the other hand, medium output (5
A recording pit irradiated with a laser beam of about 10 to 10 mW) is heated to a crystallizable temperature range equal to or lower than the melting point and then cooled to a crystalline state.

[0004] The above-described writing operation can be performed directly after the old information remains, and each recording pit changes to a state corresponding to the new information. That is, overwriting by overwriting (hereinafter abbreviated as OW) is possible. Reproduction is performed by irradiating a low-output (about 1 to 2 mW) laser beam for reading to determine whether the phase is a crystalline phase having a high reflectivity or an amorphous phase having a low reflectivity. read.

The material of the recording layer 3 is Te, S
A chalcogenide of a material containing one element of e and S is suitable, and the chalcogenide has a feature that it easily becomes amorphous. Specifically, GeTe-based materials, GeSbT
e-based materials, InSeTlCo-based materials, InSbTe-based materials, and the like.

Conventionally, in such a phase change type medium M, an interface layer made of SiO ₂ and W is formed in contact with the surface of the recording layer on the transparent substrate side or the upper and lower surfaces of the recording layer. A device having a high OW erasing rate and excellent environmental resistance has been proposed (Japanese Patent Laid-Open No. 10-106026: Conventional Example 1).

[0007] As a second conventional example, a first substrate is placed on a transparent substrate.
In the method for manufacturing a magneto-optical recording medium in which a dielectric layer, a magneto-optical recording layer, and a second dielectric layer are sequentially laminated, by forming an oxide layer obtained by oxidizing the magneto-optical recording layer with a gas containing at least ozone, A device that improves recording characteristics under the action of a low external magnetic field is known (Japanese Patent Application Laid-Open No. 6-111405).

Further, as a third conventional example, a first substrate is placed on a transparent substrate.
In a magneto-optical disk in which a dielectric layer, a magneto-optical recording layer, a second dielectric layer, and a reflective layer are laminated in this order, the surface roughness of the first dielectric layer is perpendicular to the two-dimensional plane at a period shorter than 1000 °. It has been known that the recording medium has excellent durability of recording sensitivity to repeated erasing, writing, and reproduction of 10 ⁸ times without having irregularities exceeding 100 ° in height (Japanese Patent Application Laid-Open No. Hei 8
-69643).

As Conventional Example 4, in a method for manufacturing a magneto-optical recording medium, reverse sputtering is performed on the surface of a plastic substrate in an inert gas atmosphere, and then the plastic substrate is cooled to remove dust on the surface of the plastic substrate. There is known a manufacturing method of removing pinholes to reduce the occurrence of pinholes and forming irregularities on the surface of the plastic substrate to increase the adhesion (Japanese Patent Laid-Open No. 5-128609).

Conventional Example 5 includes an organic resin substrate, a first dielectric layer, a second dielectric layer having a surface subjected to sputter etching, a magneto-optical recording layer having a surface subjected to sputter etching, and a third dielectric. A magneto-optical recording medium in which a layer and a reflective layer are provided in this order to suppress polarization noise has been proposed (JP-A-7-311987).

In prior art example 6, an organic resin substrate whose surface is sputter-etched below a certain value, a first dielectric layer made of silicon nitride, and a tantalum oxide whose surface is sputter-etched below a certain value. A second dielectric layer, a magneto-optical recording layer, a third dielectric layer, and a metal reflective layer are sequentially laminated, and the total thickness of the first dielectric layer and the second dielectric layer is within a predetermined range. Thus, there is a device that can reduce noise in a low frequency region of a reproduced signal and improve jitter characteristics (Japanese Patent Application Laid-Open No. 8-129787).

[0012]

However, in the prior art 1 described above, although the interface layer made of SiO ₂ and W is provided, the OW erasing rate is not necessarily as high as about 20 to 30 dB, and the OW erasing rate is not so high. Adhesion with the interface layer was not sufficient. In Conventional Example 2, ozone was likely to remain in the magneto-optical recording layer, which acted as an oxidizing agent and caused oxidative corrosion of the magneto-optical recording layer. Conventional Example 3 aims at forming a so-called smooth film quality having a high film density without irregularities exceeding 100 ° in the vertical direction at a cycle shorter than 1000 ° on the surface of the first dielectric layer. This is the opposite configuration.

Further, in Conventional Example 4, the unevenness is formed on the surface of the plastic substrate to improve the adhesion and prevent the substrate from warping. The conventional examples 5 and 6 are intended to improve the fluctuation of the polarization direction due to the magneto-optical effect peculiar to the magneto-optical recording medium, that is, the polarization noise in a low frequency region and the jitter characteristic of the reproduced signal.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to oxidize the surface of the intermediate layer and make the surface of the intermediate layer porous, so that the recording layer is formed at the interface between the recording layer and the intermediate layer. The purpose of the present invention is to promote generation of crystal nuclei for the formation of crystallinity, resulting in a high OW erasure rate, an improved C / N ratio, and excellent adhesion.

[0015]

The optical recording medium of the present invention comprises:
On a transparent substrate, a transparent dielectric layer, an intermediate layer, a recording layer that changes to an amorphous or crystalline phase according to the output of irradiation light, and a reflective layer are sequentially laminated, and the intermediate layer is entirely silicon carbide. And / or a porous coating containing silicon nitride as a main component at the interface on the recording layer side with silicon nitride as a main component.

According to the present invention, with the above-described structure, crystal nuclei of the recording layer are easily generated at the interface between the intermediate layer and the recording layer when the temperature rises due to light rays. As a result, the recording layer changes from an amorphous state to a crystalline state. And the characteristics such as the OW erase ratio and the C / N ratio are improved. In other words, the porous shape makes the surface uneven, and the crystal easily grows from the tip of the projection of the unevenness as a starting point. In other words, crystal nuclei are generated on the protrusions in the process of heating and cooling the recording layer, and then crystals grow around these crystal nuclei. On the other hand, in the case of a surface having almost no unevenness, even if a crystal partially grows, the crystal growth is difficult to progress overlapping with the amorphous portion. Further, in the present invention, the adhesion between the intermediate layer and the recording layer is increased by the unevenness.

The method of manufacturing an optical recording medium according to the present invention is characterized in that, after forming the intermediate layer, bombarding or reverse sputtering is performed in an oxygen atmosphere to oxidize the surface of the intermediate layer to make it porous. And

The manufacturing method according to the present invention comprises the steps of:
C of C, N of SiN and oxygen plasma react to produce CO ₂ ,
By dissociating it as nitrogen oxide, it becomes a finely etched state in a place where the amount of Si is small, and becomes a fine porous state. On the other hand, where Si is present, Si reacts with O to form silicon oxide, and a porous film containing silicon oxide as a main component and being porous is formed on the surface of the intermediate layer. At the interface between the coating of the intermediate layer and the recording layer, the generation of crystal nuclei in the recording layer is promoted. Further, active oxygen of silicon oxide on the surface of the coating film and the recording layer are bonded to each other, and the adhesion between the two layers is increased.

[0019]

FIG. 2 shows a basic layer structure of a medium M1 according to the present invention. In the same figure, 11 is a disk-shaped transparent substrate made of polycarbonate, polyolefin, epoxy resin, acrylic resin, glass, tempered glass having a resin layer formed on the surface, translucent ceramic, etc., and 12 is ZnS
The first transparent dielectric layer composed of -SiO _2, etc., 13 intermediate layer, 13a is in the interface between the recording layer porous film, 1
Phase change recording layer 4, 15 is a second transparent dielectric layer made of ZnS-SiO ₂ or the like, 16 is a reflective layer made of Al or the like.

In the present invention, the recording layer 14 is made of GeTe,
Materials such as GeSbTe, InSeTlCo, and InSbTe are preferable. Among them, GeTe and GeSbTe have a large number of rewritable times, can be crystallized for a short time when crystallizing, and have high stability in an amorphous state. preferable.

Further, when a Ge _a Sb _b Te _c, 5
at (atomic)% ≦ a ≦ 70 at% is preferable, and a <5 at%
In this case, the crystallization rate is low, and when 70 at% <a, the amorphous state becomes unstable. 0 at% ≦ b ≦ 50 at% is preferable and 5 at%
When 0 at% <b, the amorphous state becomes unstable. 40at
% ≦ c ≦ 70 at% is good. When c <40 at%, the crystallization temperature is too high, and when 70 at% <c, the crystallization temperature is too high.

The recording layer 14 has a thickness of 5 to 50 nm.
If the thickness is less than 5 nm, the difference in reflectance between the crystalline state and the amorphous state becomes small, and if it exceeds 50 nm, characteristic deterioration such as BER (Bit Error Rate) due to repeated recording / reproduction increases. More preferably, it is 10 to 40 nm.

The intermediate layer 13 of the present invention is entirely composed mainly of silicon carbide (SiC) and / or silicon nitride (SiN: amorphous SiN), and has an interface on the recording layer 14 side of silicon oxide ｛SiO _x (0.5 .Ltoreq.x.ltoreq.2.0)} and has a porous coating 13a. The thickness of the intermediate layer 13 is preferably from 20 to 400 °, and if it is less than 20 °, it is difficult to make it porous, and if it exceeds 400 °, irregular reflection of light occurs at the interface between the intermediate layer 13 and the recording layer 14. More preferably, it is 60 to 200 °.

Further, the thickness of the coating 13a is
Less than the thickness of, preferably 20 to 100 °,
If it is less than 20 °, it is difficult to make it porous, and 10 °
If it exceeds 0 °, irregular reflection of light occurs at the interface between the coating 13a and the recording layer 14. The surface roughness of the coating 13a has a maximum height difference of 20 to 100 °, and if it is less than 20 °, it is insufficient as a porous material exhibiting the effects of the present invention.
When Å is exceeded, diffuse reflection of light increases, and the C / N ratio and OW
The erasure rate deteriorates. More preferably, it is 60 to 80 °.

The maximum height difference is determined by a unit length (for example, 1 μm).
m) The maximum and minimum peaks and valleys (minimum)
peak) in the vertical direction. The measurement of the surface roughness is repeated about three times by taking a micrograph of a cut surface at a plurality of locations and measuring a maximum height difference within a unit length arbitrarily extracted, and an average value of the obtained data. And so on.

In the manufacturing method of the present invention, after the intermediate layer 13 is formed, bombarding (exposure in oxygen plasma) or reverse sputtering is performed in an oxygen atmosphere. The oxygen concentration in the oxygen atmosphere is preferably about 100% at a degree of vacuum of 0.1 to 10.0 Pa.

In the manufacturing method of the present invention, it is preferable that the oxygen atmosphere does not contain other gases such as Ar. If Ar or the like is contained, Si is dissociated, and the surface of the film 13a is unlikely to be porous.

The bombarding treatment is performed at 1 × 10 ⁻³ to 1 ×
100 sccm of O ₂ is added in a vacuum of about 10 ⁻⁴ Pa to form an atmosphere of 0.1 to 10.0 Pa,
This is a process of disposing the transparent substrate 11 in parallel between electrodes for applying a high-frequency power of 0.0 kW and exposing the substrate to oxygen plasma.

In the reverse sputtering process, the transparent substrate 11 is set on the cathode, and is placed in a range of 1 × 10 ^-3 to 1 × 10 ³
100 sccm of O ₂ is added in a vacuum of about ⁻⁴ Pa to form an atmosphere of 0.1 to 10.0 Pa.
For example, a high-frequency power of 0 kW is applied to perform a sputtering process.

The first and second transparent dielectric layers 12, 15
, Which functions as a protective layer of the recording layer 14 and the intermediate layer 13, the material is ZnS-SiO _2, SiN material, SiON-based _{material, SiO 2, SiO, TiO 2} , A
l ₂ O ₃ , Y ₂ O ₃ , TaN, AlN, ZnS, Sb ₂
S ₃ , SnSe ₂ , Sb ₂ Se ₃ , CeF ₃ , amorphous Si (hereinafter referred to as a-Si), TiB ₂ , B ₄
C, B, C, etc. are preferred.

In particular, ZnS-SiO _{2 is} preferred, and this material has little change in characteristics at high temperatures. (ZnS) _x (Si
O ₂ ) When _100-x , 60 at% ≦ x ≦ 95 at%
Is preferable, and when x <60 at%, heat resistance is poor, and x>
At 95 at%, the particle size of ZnS becomes large and the jitter is deteriorated.

The reflection layer 16 is made of Al, A having a high reflectance.
1Cr alloy, AlCu alloy, AlTi alloy, Au, A
g, AuCu alloy, Pt, AuPt alloy and the like are preferably used.

Thus, in the optical recording medium of the present invention, crystal nuclei of the recording layer are easily generated at the interface between the intermediate layer and the recording layer,
As a result, the speed at which the recording layer changes from the amorphous state to the crystalline state is increased, the properties such as the OW erasure rate and the C / N ratio are improved, and the adhesion between the intermediate layer and the recording layer is increased. .

In the present invention, each of the above-mentioned layers is
2 each of which is laminated on both sides of the
By attaching two transparent substrates 11, the recording capacity may be doubled. The present invention is not limited to the light intensity modulation method of pulse-modulating a laser beam, but is also applicable to a heating method using energy beams such as electron beams and electromagnetic waves. The medium M1 of the present invention is a rewritable optical disc, such as DVD (digital video disc),
The present invention can be applied to optical disks such as D (compact disk) and CD-ROM.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0036]

Embodiments of the present invention will be described below.

Example 1 The medium M1 (optical disk) shown in FIG. 2 was constructed as follows. On the main surface of the disk-shaped transparent substrate 11 a 3.5 inch diameter made of polycarbonate, thickness of about 1000 Å, the first transparent dielectric layer 12 made of ZnS-SiO _2, thickness of about 200 Å, a Si ₄ C major Intermediate layer 13 as a component, thickness of about 400 °, Ge ₂ Sb ₂
Recording layer 14, a thickness of about 300Å consisting Te _5, ZnS-
The second transparent dielectric layer 15 made of SiO ₂ , having a thickness of about 100
The reflecting layer 16 made of Al and Al was sequentially formed by magnetron sputtering.

At this time, after forming the intermediate layer 13, 1 × 10
^{It is said that} 100 sccm of O ₂ is added in a vacuum of about ^-4 Pa to form an atmosphere of 1.0 Pa, and a transparent substrate 11 is placed in parallel between electrodes for applying a high-frequency power of 1.0 kW and exposed to oxygen plasma. A bombardment treatment was performed to form a porous coating 13 a on the surface of the intermediate layer 13. And the bombard time is 5 seconds, 10 seconds, 20 seconds, 40 seconds,
By changing to 80 seconds and 160 seconds, the maximum height difference is about 20 °, about 40 °, about 60 °, about 80 °, about 100 °.
{Circle around (6)}, and six kinds of optical discs were produced. In this case, the thickness of the coating 13a substantially corresponded to the maximum height difference.

As a comparative example 1, a medium M2 (optical disk) as shown in FIG. 3 was produced as follows. Medium M
Reference numeral 2 denotes a film having a thickness of about 1000 °
A first transparent dielectric layer 22 made of ZnS-SiO ₂ , a film thickness of about 400 °, a recording layer 23 made of Ge ₂ Sb ₂ Te ₅ ,
A second transparent dielectric layer 24 made of ZnS-SiO _{2 having a} thickness of about 300 °, a reflective layer 2 made of Al having a thickness of about 1000 °
5 was sequentially formed by a magnetron sputtering method. At this time, the maximum height difference at the interface of the first transparent dielectric layer 22 on the recording layer 23 side was about 10 °.

Next, as a comparative example 2, a medium M3 (optical disk) as shown in FIG. 4 was manufactured as follows. Medium M
Reference numeral 3 denotes a film having a thickness of about 800 ° and a thickness of Z on a main surface of a 3.5-inch diameter disk-shaped transparent substrate 31 made of polycarbonate.
a first transparent dielectric layer 32 of nS—SiO ₂ , a thickness of about 200 °, an intermediate layer 33 of SiC, a thickness of about 400
記録, a recording layer 34 of Ge ₂ Sb ₂ Te ₅ , having a thickness of about 3
00 °, second transparent dielectric layer 3 made of ZnS—SiO ₂
5. A reflective layer 36 made of Al and having a thickness of about 1000 ° was sequentially formed by magnetron sputtering. At this time, the maximum height difference at the interface of the intermediate layer 33 on the recording layer 34 side was about 10 °.

Then, regarding these, the C / N ratio, OW
Table 1 shows the results of measuring the erasure rate and the adhesion.

[0042]

[Table 1]

Incidentally, the adhesion in Table 1 was evaluated by using a microscope after observing the peeling of the film under a microscope at 80 ° C. and 90% relative humidity for 250 hours. The area of contact was indicated by%.

The OW erasure rate was measured as follows. First, the linear velocity of the track on the optical disk is set to 6.1.
Irradiated with a laser beam pulse-modulated to 13 mW (corresponding to an amorphous state) and 5 mW (corresponding to a crystalline state) at a light wavelength of 830 nm and recording at 4.91 MHz and a pulse width of 30 ns at a wavelength of 830 nm, Next, OW was performed at 1.84 MHz and a pulse width of 30 ns, and the difference between the carrier level at 4.91 MHz before OW and the carrier level at 4.91 MHz after OW was defined as the OW erasure rate.

As shown in Table 1, the product of the present invention has a C / N ratio,
As for the OW erasure rate and the adhesiveness, the properties were superior to those of the comparative example.

(Example 2) The intermediate layer 13 was formed to a thickness of about 200
The medium was configured in the same manner as the medium M1 of Example 1 except that Si ₄ N was used. The coating 13a was formed by performing the same bombarding treatment as in Example 1 after forming the intermediate layer 13. At this time, the bombard time is 10 seconds, 20 seconds,
By changing to 40 seconds, 80 seconds, 160 seconds, and 320 seconds, the maximum height difference is about 20 °, about 40 °, about 60 °,
Six types of optical disks of about 80 °, about 100 °, and about 120 ° were produced.

Further, as Comparative Example 3, the layer structure was basically the same as that of the medium M2 of FIG.
First transparent dielectric layer 22 made of S-SiO ₂ , having a thickness of about 4
Recording layer 23 of Ge ₂ Sb ₂ Te ₅ , thickness of about 300 °, second transparent dielectric layer 24 of ZnS—SiO ₂ , thickness of about 1000 °, reflective layer 25 of Al
Were sequentially formed by magnetron sputtering. At this time, the maximum height difference at the interface of the first transparent dielectric layer 22 on the recording layer 23 side was about 10 °.

As Comparative Example 4, the layer structure is basically the same as that of the medium M3 in FIG.
First transparent dielectric layer 32 of iO ₂ , thickness of about 200
中間, an intermediate layer 33 made of Si ₄ N, a film thickness of about 400 Å, G
The recording layer 34 made of e ₂ Sb ₂ Te ₅ , having a thickness of about 300
Å, a second transparent dielectric layer 35 made of ZnS—SiO ₂ ,
A reflective layer 36 made of Al and having a thickness of about 1000 ° was sequentially formed by a magnetron sputtering method. At this time, the maximum height difference at the interface of the intermediate layer 33 on the recording layer 34 side was about 10 °.

The C / N ratio, OW
Table 2 shows the results of measuring the erasure rate and the adhesion.

[0050]

[Table 2]

Incidentally, the adhesion in Table 2 was evaluated by using a microscope after observing the peeling of the film under a microscope at 80 ° C. and a relative humidity of 90% for 250 hours. The area of contact was indicated by%.

The OW erasure rate was measured as follows. First, the linear velocity of the track on the optical disk is set to 8.0.
At 0 m / s, a laser beam pulse-modulated to 13 mW (corresponding to an amorphous state) and 5 mW (corresponding to a crystalline state) at a light wavelength of 830 nm is applied, recording is performed at 5.33 MHz, and then 1.84 MHz. , With pulse width 30 ns
And the carrier level and OW at 5.33 MHz before OW
The difference in carrier level at 5.33 MHz later was defined as the OW erase ratio.

As shown in Table 2, the product of the present invention has a C / N ratio,
As for the OW erasure rate and the adhesiveness, the properties were superior to those of the comparative example. In the case of the intermediate layer made of Si ₄ N of Example 2, the bombard time was about twice as long as that of Si ₄ C. This is probably because the bonding force of the components of the intermediate layer is stronger in Si ₄ N than in Si ₄ C.

(Example 3) The intermediate layer 13 was formed to a thickness of about 200
The medium was configured in the same manner as the medium M1 of Example 1 except that Si ₈ CN of Å was used. The coating 13a was formed by performing the same bombarding treatment as in Example 1 after forming the intermediate layer 13. At this time, the bombard time was 7 seconds, 15 seconds,
By changing to 30 seconds, 60 seconds, 120 seconds, and 240 seconds, the maximum height difference is about 20 °, about 40 °, about 60 °,
Six types of optical disks of about 80 °, about 100 °, and about 120 ° were produced.

As a comparative example 5, the layer structure is basically the same as that of the medium M3 of FIG.
First transparent dielectric layer 32 of iO ₂ , thickness of about 200
中間, an intermediate layer 33 made of Si ₈ CN, and a film thickness of about 400Å,
The recording layer 34 made of Ge ₂ Sb ₂ Te ₅ , having a thickness of about 300
Å, a second transparent dielectric layer 35 made of ZnS—SiO ₂ ,
A reflective layer 36 made of Al and having a thickness of about 1000 ° was sequentially formed by a magnetron sputtering method. At this time, the maximum height difference at the interface of the intermediate layer 33 on the recording layer 34 side was about 10 °.

The C / N ratio, OW
Table 3 shows the measurement results of the erasure rate and the adhesion.

[0057]

[Table 3]

Incidentally, the adhesion in Table 3 was determined by observing the peeling of the film with a microscope after standing for 250 hours in an environment of 80 ° C. and 90% relative humidity. The area of contact was indicated by%.

The measurement of the OW erasure rate was performed as follows. First, the linear velocity of the track on the optical disk is set to 8.0.
At 0 m / s, a laser beam pulse-modulated to 13 mW (corresponding to an amorphous state) and 5 mW (corresponding to a crystalline state) at a light wavelength of 830 nm is applied, recording is performed at 5.33 MHz, and then 1.84 MHz. , With pulse width 30 ns
And the carrier level and OW at 5.33 MHz before OW
The difference in carrier level at 5.33 MHz later was defined as the OW erase ratio.

As shown in Table 3, the product of the present invention has a C / N ratio,
As for the OW erasure rate and the adhesiveness, the properties were superior to those of the comparative example. Further, in the case of the intermediate layer made of Si ₈ CN of Example 2, the bombard time was about the middle of these as compared with Si ₄ C and Si ₄ N. This is probably because the bonding force of the components of the intermediate layer is about the middle between Si ₄ N and Si ₄ C.

[0061]

According to the present invention, the intermediate layer has a porous coating containing silicon carbide and / or silicon nitride as a main component as a whole and silicon oxide as a main component at the interface on the recording layer side. When the temperature rises due to light irradiation, crystal nuclei of the recording layer are easily generated at the interface between the intermediate layer and the recording layer, and as a result, characteristics such as C / N ratio and OW erasure rate are improved. Further, the provision of the intermediate layer has the effect of improving the adhesion of the entire layer.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a conventional optical recording medium M.

FIG. 2 is a partial cross-sectional view of the optical recording medium M1 of the present invention.

FIG. 3 is a partial cross-sectional view of an optical recording medium M2 of Comparative Example 1.

FIG. 4 is a partial cross-sectional view of an optical recording medium M3 of Comparative Example 2.

[Explanation of symbols]

 1: transparent substrate 2: first transparent dielectric layer 3: recording layer 4: second transparent dielectric layer 5: reflective layer 11: transparent substrate 12: first transparent dielectric layer 13: intermediate layer 13a: porous Coating 14: Recording layer 15: Second transparent dielectric layer 16: Reflective layer

Claims (2)

[Claims] A transparent dielectric layer, an intermediate layer, a recording layer which changes into an amorphous or crystalline phase according to the output of irradiation light, and a reflective layer are sequentially laminated on a transparent substrate. An optical recording medium comprising a porous coating mainly composed of silicon carbide and / or silicon nitride as a main component and silicon oxide as a main component at an interface on a recording layer side. 2. The method for manufacturing an optical recording medium according to claim 1, wherein after the formation of the intermediate layer, the surface of the intermediate layer is oxidized by bombarding or reverse sputtering in an oxygen atmosphere. A method for producing an optical recording medium, comprising: