JP2001184723A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical disk having stable recording and erasing performances and ensuring such good repetitive recording characteristics as to suppress the deterioration of characteristics and the occurrence of defects even when recording and erasure are repeated many times. SOLUTION: A base metallic layer 2, a reflecting layer 3, at least one 1st dielectric layer 4, a recording layer 5, at least one 2nd dielectric layer 6 and a light transmissive layer 7 are successively laminated on a substrate 1 with a formed rugged part to obtain the objective optical information recording medium 10 in which the arrangement of the constituent atoms of the recording layer 5 is varied by irradiation with light to record and erase information. The metallic layer 2 is a Ti layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording layer on an uneven portion side of a substrate, on which a light transmitting layer is formed. The present invention relates to an optical information recording medium in which information is recorded and erased by changing the arrangement, and particularly to an optical information recording medium (hereinafter, referred to as an optical disk) having excellent high-density recording and rewriting characteristics.

[0002]

2. Description of the Related Art In recent years, research on optical data recording systems has been advanced in various places. This has a number of advantages, such as the ability to achieve a recording density that is at least an order of magnitude higher than the magnetic recording method, and the ability to support read-only, write-once, and rewritable memory types. This is because a wide range of applications can be considered. Recently, a rewritable DVD has been put on the market, but the recording capacity is still not enough, and only 1 to 1.5 hours can be recorded in a standard recording mode when compared with a VTR using a tape as a recording medium. . In the future, with the digitalization of the broadcasting system, when recording higher definition video sources, even higher capacity and higher density are required for rewritable optical disks.

[0003]

By the way, in response to the demand for higher density, the lens has a higher NA (numerical aperture), and the focal length between the medium and the lens tends to be shorter. Along with this, signal reading by laser light has been conventionally performed from the substrate side. However, since the focal length is small, the distance between the lens substrates is short, and reading from the substrate side becomes difficult.
As a workaround, a method of directly reading data from the uneven surface (signal surface, recording film surface) side via a transparent layer is adopted.

A recording / reproducing medium usually has a multilayer structure, but in this case, the film structure for the substrate is reversed. In a phase change recording medium, a reflective film is deposited on a substrate as a first film formation layer. Al and Al-based alloy films, which are often used as a reflection layer, have the property that crystal grain boundaries grow as they are deposited. In the film configuration read out from the substrate side, the reflective layer is the outermost layer except for the protective film, and even if Al and an Al-based alloy film are used as the reflective layer, the laser light reflective surface is in the initial stage of film formation, and the influence of grain boundary growth is small. There was no. However, in the configuration in which reading is performed from the recording film surface, the Al and Al-based alloy reflection layer becomes the first layer formed on the uneven groove surface, and the dielectric layer and the recording layer are sequentially laminated on the film grown at the grain boundary. As a result, the surface roughness caused by the grain boundaries greatly affects the dielectric layer and the recording layer, and causes deterioration in recording / reproducing characteristics and rewriting performance.

[0005]

According to the present invention, as a first invention, a substrate 1 having an uneven portion is provided.
A base metal layer 2, a reflective layer 3, at least one first dielectric layer 4, a recording layer 5, at least one second dielectric layer 6, and a transparent (light transmitting) layer 7 are sequentially laminated thereon. The optical information recording medium 10 on which information is recorded and erased by changing the arrangement of atoms constituting the recording layer 5 by light irradiation
An optical information recording medium in which the base metal layer 2 is a Ti layer according to a second aspect of the present invention, wherein the base metal layer 2 has a thickness of 10 nm to 60 nm and the reflective layer is Al or Al-based. The problem has been solved by providing each of the optical information recording media according to claim 1 which is an alloy.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disk according to the present invention will be described in detail. The recording material of the present invention can be made of Ag, In, S which can take at least two states of a crystalline state and an amorphous state.
b, Te phase-change optical recording material or Ge, S
This is a phase change type optical recording material composed of b and Te. In the crystal state that is the erased state, a single crystal phase of Ag, In, Sb, and Te or a crystal phase composed of a combination of two or more elements is formed. The crystal state is not limited to a single phase, and two or more crystal phases may coexist. In the amorphous state, which is a recording state, an X-ray diffraction pattern is not shown, but a short-range order may be locally present, and a regular electron beam diffraction pattern may be shown.

The recording layer of the present invention (phase-change recording layer)
With this method, even if recording, erasing, or rewriting by overwriting is repeated, excellent repetition durability and high-density recording can be obtained as compared with the conventional recording layer. Further, since a higher degree of modulation can be obtained as compared with the conventional recording layer, jitter during high-density recording / reproduction is suppressed and high performance is achieved.

A typical layer structure of the optical disk 10 according to the present invention will be described below in more detail with reference to FIG. 1. As shown in FIG. 1, a transparent substrate 1 / underlying metal layer 2 / reflection layer 3 / first dielectric layer 4 /
Recording layer 5 / second dielectric layer 6 / transparent layer 7 as light transmitting layer
(Here, the laser beam enters from the transparent layer 7 side). However, the configuration of the optical disk 10 according to the present invention is not limited to this.

FIG. 1 is a view for explaining a sectional structure of an embodiment of an optical disk 10 according to the present invention. An optical disk 10 according to the present invention includes a base metal layer 2, a reflective layer 3, a first dielectric layer 4, a recording layer 5, a second dielectric layer 6,
The transparent layers 7 are sequentially laminated.

The dielectric layer of the present invention (first and second dielectric layers)
The effects of protecting the substrate 1 and the recording layer 5 from heat, such as preventing the substrate 1 and the recording layer 5 from being deformed by heat and deteriorating the recording characteristics during recording, and the optical interference effect, This has the effect of improving the signal contrast during reproduction. Further, there is an effect that crystallization of the recording layer 5 is promoted to improve the erasing rate. As the dielectric layers 4 and 6, Zn
There are inorganic thin films such as S, SiO ₂ , Si ₃ N ₄ and Al ₂ O ₃ . In particular, a thin film of a metal or semiconductor oxide such as Si, Ge, Al, Ti, Zr, or Ta; a thin film of a metal or semiconductor nitride such as Si, Ge, or Al;
Thin films of metals such as Hf and Si or carbides of semiconductors,
Thin films of sulfides of metals or semiconductors such as ZnS, In ₂ S ₃ , TaS ₄ , and GeS ₂ , and films of a mixture of two or more of these compounds are preferable because of high heat resistance and chemical stability. .

Using the optical interference effect, the reflectance,
In order to further improve the signal contrast and the like at the time of reproduction, it is preferable to laminate two or more dielectric layers (first and second dielectric layers) 4 and 6 based on a precise optical calculation result. In order to prevent the element components of the dielectric layers 4 and 6 that contact the interface with the recording layer 5 that repeats melting and cooling from diffusing into the recording layer 5, one dielectric layer is provided on both interfaces or on one surface. Is preferably added. By suppressing the diffusion, it is possible to improve the rewrite characteristics repeatedly.
In order to reverse the contrast between the crystal and the amorphous, it is preferable to add an absorbing dielectric layer for the purpose of controlling the absorptance. Reversing the contrast is effective for increasing the transfer rate. For the above reason, it is preferable that the dielectric layer be at least one layer or more.

Further, it is preferable that there is no diffusion of atoms constituting the dielectric layer into the recording layer 5. These oxides, sulfides, nitrides, and carbides do not always need to have a stoichiometric composition, and it is effective to control the composition for controlling the refractive index and the like, or to use a mixture thereof.

A mixture of these and a fluoride such as MgF ₂ is also preferable because the residual stress of the film is small. In particular, a mixed film of ZnS and SiO ₂ is preferable because deterioration of recording sensitivity, C / N, erasure rate, and the like hardly occurs even when recording and erasing are repeated.

The thickness of the first and second dielectric layers 4 and 6 is about 10 nm to 500 nm. The thickness of the first dielectric layer 4 is preferably 10 nm to 50 nm because recording characteristics such as C / N and erasing rate and stable rewriting can be performed many times. In addition, the second dielectric layer 6 is difficult to peel off from the transparent layer 7 and the recording layer 5 and is unlikely to cause defects such as cracks.
0 nm to 300 nm is preferred. The first dielectric layer 4 and the second
The dielectric layers 6 may be made of different compounds instead of the same.

The thickness of the recording layer 5 of the present invention is not particularly limited, but is 10 nm to 100 nm. The reasons are as follows. The thickness of the recording layer 5 is 10 n
If m or less, the difference between the reflectance in the crystalline state and the reflectance in the amorphous or microcrystalline state, that is, a sufficient degree of modulation cannot be obtained, and the reproduction signal intensity cannot be large. When the thickness of the recording layer 5 is 100 nm or more, crystallization is not completely performed within the laser beam irradiation time due to the large heat capacity of the recording layer 5 (there is no erased), or the recording layer 5 is sufficiently amorphous during recording. Degradation of recording and erasing is caused, for example, a portion to be recrystallized without quality.

Further, when the thickness of the recording layer 5 is 40 nm or more, when direct overwriting is repeated, mass transfer occurs in the recording mark, and as a result, the thickness of the recording layer fluctuates, and recording and erasing are performed with overpower. Therefore, the repetition characteristics deteriorate. In the composition of the recording layer 5 of the present invention,
In particular, the recording and erasing sensitivity is high, and the recording and erasing can be performed many times.

As a material of the reflection layer 3 of the present invention, Al having light reflectivity, or mainly containing Al, Ag,
Au, Cu, Co, Ni, Ti, V, Mo, Mn, P
t, Si, Nb, Fe, Ta, Hf, Ga, Pd, B
An alloy containing at least one additive element selected from i, In, W, and Zr. The thickness of the reflective layer 3 is approximately 50 nm or more and 150 nm or less.

In particular, it is preferable to constitute the main part of the optical disc because of its high recording sensitivity, high-speed single-beam overwriting, high erasure rate and good erasure characteristics.

The material of the reflective layer 3 of the present invention includes:
Al, Au, C mainly composed of Ag having light reflectivity
u, Co, Ni, Ti, V, Mo, Mn, Pt, Si,
Nb, Fe, Ta, Hf, Ga, Pd, Bi, In,
An alloy containing at least one additional element selected from W and Zr. An alloy containing Ag as a main component is preferable because it has high light reflectivity and high thermal conductivity.

As the metal underlayer 2 of the present invention, a Ti film for improving the crystal orientation of the (111) plane of the Al and Al-based alloy reflection layer is suitable, and the thickness is preferably 10 nm to 60 nm. When the Al and Al-based alloy reflection layer is formed directly on the resin substrate in a vacuum, Al and Al that fly
This is because a smooth reflective surface is formed by the growth of the fine particles of the system alloy. However, as the deposition proceeds, the grain boundaries grow, and as a result, the smoothness of the reflection surface decreases, and the noise of the laser beam reflected light increases.

The coarsening of the crystal grain boundaries of the Al and Al-based alloy films can be suppressed by suppressing the random crystal orientation and improving the crystal orientation of the Al (111) plane. This is because Al (1), which is the closest dense face of the face-centered cubic lattice,
11) When the ratio of the surface is increased, the unevenness is reduced and the smoothness is increased by the action of lowering the energy of the system.

The Ti film has a (002) crystal orientation, and promotes the growth of a (111) crystal plane having a close-packed structure formed thereon. When the Ti film is 10 nm or less, (00
2) Since the orientation of the plane is insufficient, the crystal orientation of the Al (111) plane is scarcely recognized, and when the Ti film has a thickness of 60 nm or more, the thickness of the Ti film having low thermal conductivity is increased. It prevents diffusion and inhibits crystallization of the recording film. The thickness of the Ti underlayer is preferably 10 nm to 60 nm.

As the transparent layer 7 of the present invention, a resin layer which is cured by ultraviolet rays, or a sheet of glass, polycarbonate, polymethyl methacrylate, polyolefin resin, epoxy resin, polyimide resin or the like can be used. The sheet is bonded to the recording layer via the adhesive layer. The thickness of the transparent layer 7 is generally not less than 100 μm and not more than 200 μm.

As the material of the substrate 1 of the present invention, various transparent synthetic resins, transparent glass and the like can be used. Dust,
To avoid the effects of scratches on the substrate, use a transparent substrate,
Recording is preferably performed from the substrate side with a focused light beam. Examples of such a transparent substrate material include glass, polycarbonate, polymethyl methacrylate, polyolefin resin, epoxy resin, and polyimide resin. In particular, optical birefringence is small, hygroscopicity is small,
Polycarbonate resins are preferred because of ease of molding. In order to further improve the recording density, a so-called table reading may be performed through a very thin translucent substrate by providing a laminated medium on the substrate. In this case, the opaque substrate is used because the laser beam does not pass through the substrate. Can be used.

Although the thickness of the substrate 1 is not particularly limited, it is practically 0.01 mm to 5 mm. 0.01m
If it is less than m, even if recording is performed with a light beam focused from the substrate 1 side, it is liable to be affected by dust. The increase in size makes it difficult to increase the recording density. The substrate 1 may be flexible or rigid. The flexible substrate 1 has a tape shape, a sheet shape,
Use in card form. The rigid substrate 1 has a card shape,
Or use it in the form of a disk. In addition, these substrates 1
After forming the recording layer 5 and the like, using two substrates,
An air sandwich structure, an air incident structure, or a close bonding structure may be used.

As a light source used for recording on the optical disk 10 according to the present invention, a laser beam is preferably used, and a light source having a wavelength of 830 nm in the near infrared region to 300 nm in the ultraviolet region is mainly used. It is also possible to use a light source in which the primary light is shortened in wavelength using a secondary harmonic generation element (SHG element).

The recording of the optical disk 10 according to the present invention is performed by irradiating the recording layer 5 in a crystalline state with a laser beam pulse or the like to form an amorphous (amorphous) recording mark. Conversely, a recording mark in a crystalline state may be formed on the recording layer 5 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. In practice, the recording peak power superimposed on the low-energy erasing power causing crystallization is applied to the recording layer 5 to overwrite the already recorded recording mark without going through the erasing process.

[0028]

Next, a method of manufacturing the optical disk 10 according to the present invention having the above-described configuration will be described. As a method for forming the base metal layer 2, the reflective layer 3, the recording layer 5, the dielectric layers 4, 6 and the like on the substrate 1, a known thin film forming method in a vacuum, for example, a vacuum deposition method (resistance heating type, Electron beam type), ion plating method, sputtering method (DC or AC sputtering, reactive sputtering, ion beam sputtering) and the like. In particular, the sputtering method is preferable because the composition and the film thickness can be easily controlled.

In the sputtering method, for example, the recording layer 5 in a mixed state can be easily formed by simultaneously sputtering the recording material and the additive material on the respective targets. The degree of vacuum before film formation is preferably set to 1 × 10 ⁻⁴ Pa or less. It is preferable to use a batch type film forming apparatus for simultaneously forming a plurality of substrates in a vacuum chamber or a single wafer type film forming apparatus for processing substrates one by one. The thickness of the reflective layer 3, the recording layer 5, the dielectric layers 4, 6 and the like to be formed is controlled by controlling the input power and time of a sputtering power source, and monitoring the deposition state by a quartz vibrating type film thickness meter or the like. Thus, it can be easily performed.

The formation of the reflection layer 3, the recording layer 5, the dielectric layers 4, 6 and the like may be performed while the substrate 1 is fixed, or moved or rotated. The substrate 1 is preferably rotated on its own axis because of excellent in-plane uniformity of the film thickness, and more preferably combined with revolution. When the substrate 1 is cooled as required, the amount of warpage can be reduced.

Next, further specific examples of the embodiments will be described, but the present invention is not limited to these specific examples.

[0032]

Embodiment 1 Laser diode with wavelength of 650 nm, NA
Recording (one-beam overwriting) was performed using an optical disk drive tester equipped with an optical lens of = 0.60. The reproducing light power Pr was constant at 0.7 mW regardless of the linear velocity. Evaluation was performed at a linear velocity of 3.5 m / s using a random pattern of the modulation signal. Slice at the center of the amplitude of the playback signal, clock-to-data jitter
to data jitter was measured. The medium has a diameter of 120 mm,
It was formed on a polycarbonate resin substrate having a thickness of 1.2 mm. The substrate was subjected to groove recording with a track pitch of 0.74 μm (groove pitch 1.48 μm). The groove depth is 40 nm and the ratio of the groove width to the land width is about 4
6:54.

While the substrate 1 is planetary rotating at 60 revolutions per minute, vacuum formation is performed in the order of the base metal layer 2, the reflective layer 3, the first dielectric layer 4, the recording layer 5, and the second dielectric layer 6 by a sputtering method. The membrane was made. First, 6 × 10
After evacuating to ^-5 Pa, 1.6 × 10 ^-1 Pa Ar gas was introduced. Ti was sputtered by a DC power supply to form a base metal layer 2 having a thickness of 30 nm. An Al film was formed as a reflective layer 3 on this Ti film by sputtering with a DC power supply to a thickness of 100 nm. The Ar gas pressure when forming the Al film is 3 mTorr.
r or less is desirable.

ZnS to which 20 mol% of SiO ₂ is added
To the Al reflection layer 3 by a high-frequency magnetron sputtering method.
A 17-nm-thick first dielectric layer was formed thereon. Subsequently, the recording layer 5 was formed by sputtering a four-element single target (diameter: 2 inches, thickness: 3 mm) made of Ag, In, Sb, and Te using a DC power supply. That is, as a specific composition, Ag0.05, In0.05, Sb0.61, Te
A recording layer 5 having a thickness of 23 and a thickness of 23 nm was formed. In the composition analysis, a similar recording layer 5 was separately formed with a thickness of 100 nm on a silicon substrate, and this was analyzed by ICP emission analysis. Further, a second dielectric layer 6 of the same material as that of the first dielectric layer 4 was formed to a thickness of 70 nm.

After the optical disk thus formed is taken out of the vacuum container, an acrylic UV curable resin is sequentially dropped on the second dielectric layer 6 from the inner peripheral side to the outer peripheral side of the substrate 1 so as to have a thickness of 100 μm. The polycarbonate boat sheet was placed thereon, and the ultraviolet curable resin was spin-rotated so as to sufficiently spread between the substrate and the sheet, and was cured by irradiation with ultraviolet light to form the transparent layer 7, thereby obtaining the optical disc 10 according to the present invention.

[0036]

Comparative Example As a comparative example, the reflective layer 3 was made of Al 0.97, C
An optical disk having a composition of r0.03 and a film thickness of 150 nm and having the same configuration as that described above except for the above was produced. The optical disk manufactured in this manner was irradiated with a laser beam, a flash lamp, or the like to heat the recording layer 5 to a temperature higher than the crystallization temperature, thereby performing an initialization process.

The phase change recording layer 5 from the transparent (light transmitting) layer 7 side
The recording was performed in the groove portion which is the guide groove of No. 1. The groove is concave when viewed from the direction of incidence of the laser beam. It is known that when the direct overwrite (DOW) is repeatedly performed, the material of the recording layer 5 moves to reduce the film thickness, or the modulation degree of the reproduced signal decreases due to diffusion and incorporation of impurities. FIG. 2 shows the results of repeated direct overwrite as examples and comparative examples.

FIG. 2 is an explanatory diagram showing a comparison between the thickness of the base metal layer 2 and the thickness of the reflective layer 3 and the relationship between the overwrite and the repetitive overwrite. Jitter is the mean square of the start (LE) and end (TE) of a recording mark. Optical disc 1 according to the present invention
In the case of 0, the jitter value was kept low from the initial recording as compared with the optical disc shown in the comparative example, and the output showed a constant value even after rewriting 1,000 times, and no decrease in the output due to mass transfer of the recording layer 5 was observed. Jitter and output are both 50
No degradation occurred over 00 times. The same recording and reproduction characteristics were obtained in the land portion. Optical disc 1 according to the present invention
0 has good repetitive recording durability. In FIG. 2, ２: DOW5000
Jitter after rotation of 11% or less, ：: Jitter after jitter of 5,000 times 9% or less.

In the optical disk 10 according to the present invention, by providing a Ti underlayer as the underlayer metal layer 2 on the transparent resin substrate 1, the (111) plane crystal is formed on the Al and Al-based alloy reflection layer 3 deposited thereon. Orientation can be given, whereby coarsening of crystal grain boundaries can be suppressed, and as a result, the smoothness of the reflective layer 3 can be maintained. Therefore,
The laser light incident from the light transmitting layer, which is the transparent layer 7, is reflected or reflected and radiated by the reflecting layer 3 without loss, and it was confirmed that good recording / reproducing characteristics were obtained.

[0040]

Example 2 The thickness of the Ti underlayer 2 was 10 nm, the thickness was 0.97 Al, 0.03 Cr, and the thickness of the reflective layer 3 was 130 nm.
nm, the first dielectric layer 4 is 16 nm, and the recording layer 5 is 22 n
m, the thickness of the second dielectric layer 6 is 71 nm, and the composition of the recording layer 5 is Ag.
0.03, Al 0.04, Te 0.28, Sb 0.65
Except that the transparent layer 7 was formed in the same manner as in Example 1 described above.
And the recording / reproducing characteristics were examined. The substrate 1 used had a thickness of 0.6 mm, a groove depth of 30 nm, a land / groove width ratio of 55/45, and a continuous groove with a rack pitch of 0.74.
μm. Initialization was performed in the same manner as in Example 1.

Recording an 8-16 modulation random pattern,
Clock to data jitter was measured by slicing at the center of the amplitude of the reproduced signal. FIG. 2 shows the measurement results. As apparent from FIG. 2, the jitter after overwriting 1000 times is almost equal to the initial jitter, and
No deterioration was observed in both jitter and output after the test, and good repetitive rewriting characteristics were exhibited (in FIG. 2, ○: DOW5).
Jitter 11% or less after 000 times, ◎: Jitter 9% or less after 5000 times of DOW).

A laser beam for reproduction is applied to an optical disk formed by providing the above-mentioned Ti underlayer 2 on a substrate 1 and laminating a reflective layer 3 having a composition of Al 0.97 and Cr 0.03 thereon. When the light incident on the reflective layer 3 and the reflected light was observed by a spectrum analyzer, the optical disk provided with the Ti underlayer 2 had Al 0.97 and Cr 0.03.
For a similar disk with only the reflective layer 3 having the composition of
It was confirmed that the noise level of the C light was reduced.
That is, between the substrate 1 and the reflective layer 3,
It can be understood that it is necessary to provide

[0043]

Embodiment 3 The thickness of the Ti underlayer 2 is 60 nm, the thickness is Al 0.97, Cr 0.03, and the reflection layer 3 is 90 n.
m, the first dielectric layer 4 is 17 nm, the recording layer 5 is 22 nm,
The composition of the second dielectric layer 6 was 65 nm and the recording layer 5 was Ag.
0.04, Al 0.04, Te 0.28, Sb 0.64
Except that the transparent layer 7 was formed in the same manner as in Example 1 described above.
And the recording / reproducing characteristics were examined. The substrate 1 used had a thickness of 0.6 mm, a groove depth of 30 nm, a land / groove width ratio of 50/50, and a continuous groove with a rack pitch of 0.74.
μm. Initialization was performed in the same manner as in Example 1.

Recording an 8-16 modulation random pattern,
Clock to data jitter was measured by slicing at the center of the amplitude of the reproduced signal. FIG. 2 shows the measurement results. As apparent from FIG. 2, the jitter after overwriting 1000 times is almost equal to the initial jitter, and
No deterioration was observed in both jitter and output after the test, and good repetitive rewriting characteristics were exhibited (in FIG. 2, ○: DOW5).
Jitter 11% or less after 000 times, ◎: Jitter 9% or less after 5000 times of DOW). Also, as in the second embodiment, D
It was confirmed that the noise level of the C light was reduced.

[0045]

According to the optical disk of the present invention having the above-described structure, the recording and erasing operation is stable even when recording and erasing are repeated a large number of times, and good repetitive recording characteristics with little deterioration of characteristics and almost no defects are generated. Is obtained. That is, the present invention provides an optical disk having good recording and reproduction characteristics and high reliability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an optical disc according to the present invention.

FIG. 2 is an explanatory diagram showing a comparison between the thickness of a base metal layer and the thickness of a reflective layer and a relationship between the overwrite and the repetitive overwrite.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Underlayer metal layer 3 Reflective layer 4 First dielectric layer 5 Recording layer 6 Second dielectric layer 7 Transparent (light transmission) layer 10 Optical information recording medium

Claims (2)

[Claims] 1. A base metal layer, a reflective layer, at least one first dielectric layer, at least one recording layer, at least one second dielectric layer, and a light transmitting layer are sequentially formed on a substrate having an uneven portion. It is an optical information recording medium on which information is recorded and erased by changing the arrangement of atoms constituting the recording layer by irradiation with light, wherein the underlying metal layer is a Ti layer. Characteristic optical information recording medium. 2. The method according to claim 1, wherein the thickness of the base metal layer is 10 nm to 60 n.
2. The optical information recording medium according to claim 1, wherein m and the reflection layer are Al or an Al-based alloy.