JP2003288737A - Optical data recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an initialization-free medium, having a recording density of 4.7 GB/disc-120 mm-in-diameter or larger, which responds to high-speed overwrite recording, and is compatible with DVD-ROMs. <P>SOLUTION: An optical recording medium, having a recording layer including Sb and Te, in addition, substantially no other elements or at least one of elements of group 1 to group 7 in the periodic table and remnant layers is a phase-change recording medium, wherein the remnant layers include a material for speeding up linear velocity, and by a recording operation through energy irradiation to the optical data medium, the other elements in an amount existed in the recording layer at end of a deposition process of the recording layer or more are migrated from the remnant layers into the recording layer and exist there. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium that does not require an initialization operation, has excellent storage reliability, and is compatible with high-speed overwrite recording, and is applied to an optical disc.

[0002]

2. Description of the Related Art An optical information recording medium capable of recording, reproducing and erasing information by laser beam irradiation and an optical information recording medium capable of recording, reproducing and erasing information by laser beam irradiation have a crystalline state and an amorphous state. Phase change CD-RW, DVD-RA using reversible phase change of (amorphous) state
Commercialization as M, -RW, + RW media is expected.

The inventors of the present invention have found that, in the phase change type optical information recording medium, the recording layer is a metastable Sb belonging to the space group Fm3m.
Research and development have been conducted on a recording layer having a 3Te phase (Japanese Patent Laid-Open No. 10-21).
7069, etc.). This metastable phase is different from the recording layer having the Sb-Te eutectic structure, and is composed of Sb and Sb2Te3.
And the recording marks are not disturbed due to the crystal grain boundaries. Therefore, the metastable S belonging to the space group Fm3m
The one using a recording layer characterized by having a b3Te phase has an advantage that high density recording is possible. Further, the recording layer characterized by having a metastable Sb3Te phase belonging to the space group Fm3m is resistant to thermal shock during repeated recording, and thus has excellent repeated recording characteristics.

By the way, in a phase change type optical information recording medium using a recording layer characterized by having a metastable Sb3Te phase belonging to the space group Fm3m, the recording layer is formed by a vacuum film forming method such as sputtering or vapor deposition. The film formed and immediately after the film formation is usually in an amorphous state. On the other hand, the recording layer of the commercialized optical information recording medium must be in a crystalline state. This is because in a rewritable optical information record carrier that utilizes phase transition, the recording film is generally set to an amorphous state in the recorded state and a crystalline state in the erased (initialized) state. For this reason, an initialization process for crystallizing the recording layer by performing heat treatment such as laser beam irradiation immediately after the recording layer is formed is required. However, since the initialization process requires a time of 30 seconds or more, the throughput is reduced, and in mass production, a large number of devices for the initialization process are required and the equipment cost is increased. As a result, the product cost is increased.

To solve these problems, in addition to Sb and Te, other elements are not substantially contained or the periodic table group I to
An optical recording medium having a recording layer containing at least one kind of element belonging to Group VII, and the other layer consisting of a crystallization promoting layer composed of a crystallization promoting material and a recording state stabilizing material, By irradiating the recording medium with energy to perform a recording operation, the amount of the above-mentioned other element present in the recording layer at the end of the recording layer forming process is transferred from the other layer to the recording layer. There is a technology that does not require an initialization process because it exists (Japanese Patent Application No. 2001-3198).
87 specification). However, in recent years, the use of the phase change recording medium for high-density image recording has been expanded, and further high-speed overwriting (7 to 17 m / s, which is 2 to 5 times the linear velocity of reproduction of DVD-ROM) can be realized. It has come to be requested. Here, in order to realize high-speed overwriting, it is necessary to improve the crystallization speed of the recording layer material at the time of erasing the mark, that is, near the melting point (hereinafter referred to as “high speed”). It is difficult to deal with. This is because, according to the knowledge known so far, regarding the phase change type optical information recording medium (Japanese Patent Laid-Open No. 2000-43415), the recording layer has a metastable Sb3Te phase belonging to the space group Fm3m,
Although it is possible to speed up the recording layer material by increasing the compounding ratio of, it is not possible to provide a medium capable of high-speed overwriting at a practical level because the storage reliability of the medium is reduced accordingly. Because.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and to realize a DVD-ROM compatible 4.7 GB / diameter 120 mm or more recording density disc compatible with high speed overwrite recording. It is to realize initialization-less media.

[0007]

Means for Solving the Problems The above-mentioned problems are (1) of the present invention, in addition to “Sb and Te, the presence of an element belonging to Group I to Group VII of the Periodic Table, which is substantially free from other elements. In an optical recording medium having a recording layer containing at least one kind of element and an extra layer thereof, the extra layer contains a high linear velocity material, and the optical information medium is irradiated with energy to perform a recording operation. According to the above, the phase change recording medium in which the above-mentioned amount of the above-mentioned other element present in the recording layer at the end of the film forming step of the recording layer migrates from the remaining layer into the recording layer and is present '', (2) “The recording layer contains Sb and Te in an atomic number of 1/3 or less of Sb, and has a Ge content of 0 to less than 5 atomic%. (3) “The phase change recording medium according to item (3)“ The remaining layer is combined with a recording state stabilizing material. It said first characterized in that it is a crystallization promoting layer comprising a promoting material (1) or second (2)
(4) "The recording state stabilizing material is a Group 4 element, a Group 1B element, a Group 3 element and / or a Group 5 element. (5) “The recording state stabilizing material is Ge, Cu, In, B and / or N”. Phase change recording medium ",
(6) “The above-mentioned high linear velocity material is Ga, Dy, Ca, Mg,
(Phase change recording medium according to item (3) above, characterized in that it is at least one element selected from the group consisting of Mn), (7) "The high linear velocity material is Ga or / and Mn. (8) The phase change recording medium according to item (6) above, "(8)" wherein the crystallization promoting material is a Group 5 element or a Group 6 element. (3) Phase change recording medium ”, (9)“ The crystallization promoting material is Sb, Bi and / or Te, The phase change recording medium according to the above (8). Is achieved.

In addition to Sb and Te, it has a recording layer containing substantially no other element or containing at least one kind of element belonging to Group I to Group VII of the periodic table, and the remaining layer. In the optical recording medium, the optical recording medium is irradiated with energy to perform a recording operation, so that the amount of the other element present in the recording layer at the end of the film forming step of the recording layer is increased from the other layer. The above problem was solved by migrating into the recording layer so that the remaining layer was a crystallization promoting layer containing a recording state stabilizing material, a crystallization promoting material and a high linear velocity material. It is a thing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The feature of the present invention is that the phase change recording is such that, by recording, a larger amount of a sub-component (hereinafter, also referred to as “impurity”) present in the recording layer at the end of the film-forming process is present in the recording layer. It is a medium. Sb and Te as the main components in the present invention are in contrast with the sub-components, Sb and Te in the recording layer maintain the Sb3Te composition, and the recording material of the recording layer performs write operation and erase. This means maintaining a quantity ratio such that an amorphous phase-crystalline phase can be phase-converted by an operation. The crystallization promoting layer contains a recording state stabilizing material as an impurity, and the impurities are diffused into the recording layer during phase change recording, so that the amount of impurities present in the recording layer at the end of the film formation process is present in the recording layer. become. Therefore, it is possible to reduce the recording state stabilizing material that should be included in the recording material in advance.

Further, in the present invention, the crystallization promoting layer contains a high linear velocity material as an impurity. The high linear velocity material has the effect of increasing the crystallization speed of the recording material near the melting point, and realizes high speed overwriting (DVD-ROM
2 to 5 times the reproduction linear velocity of 7 to 17 m / s). It should be noted that, by adding the high linear velocity material, the recording layer material can be sped up without increasing the proportion of Sb occupying the recording layer. Therefore, the storage reliability is lowered as the recording layer material is sped up. There is no problem of being lost.

As the high linear velocity material, a group of Ga, Dy,
It is preferable to use at least one element selected from Ca, Mg and Mn. These are the results of investigating the addition effect to the phase change type optical information recording medium having the Sb3Te phase with respect to many elements on the periodic table, and confirmed the effect of increasing the speed of the recording layer material.

Ga and / or M in the group
n is particularly preferred. Although each of Dy, Ca, and Mg can achieve high speed, it has a problem that when it is contained in a large amount, repeated recording characteristics are deteriorated. Ga is
Similar to Dy, Ca, and Mg, it has a problem of repeatedly deteriorating recording characteristics, but has an effect of improving storage characteristics. For this reason, it is possible to speed up and stabilize the recording state. On the other hand, Mn is not as effective in improving storage characteristics as Ga, but does not cause deterioration in repetitive recording characteristics even when contained in a large amount. From these, by using Ga and / or Mn as the material for increasing the linear velocity, it is possible to realize a phase change recording medium having good repeating characteristics and further excellent storage characteristics.

When Ge is used as the recording state stabilizing material contained in the crystallization promoting layer, Ge contained in the recording material is 5
It may be less than atomic%. When Ge contained in the recording material in the crystalline recording layer of the Sb3Te-based recording layer is less than 5 atom%, the crystallization temperature is less than 160 ° C. When the crystallization temperature is lower than 160 ° C., the use of the crystallization promoting layer makes it possible to form a crystal recording film having a relative reflectance of 80% even in the film forming process at the plastic deformation temperature of the polycarbonate substrate or lower. More preferably, Ge is less than 3 atomic% for forming the crystalline recording layer, and most preferably, the recording material does not contain Ge. Here, the case where Ge contained in the recording material is less than 1 atomic% is defined as substantially free of Ge. Ge contained in Sb3Te-based recording material is 3 atom%
In the case of, the crystallization temperature is 147 ° C, and in the case of less than 1 atom%, it is 110 ° C. When the former crystallization temperature is 147 ° C., the crystal recording film can be used without initialization even at the above-mentioned polycarbonate substrate heat resistant temperature of 67 ° C. Its relative reflectance is 8
It is about 0%. In the latter case where the crystallization temperature is 110 ° C., a more complete crystal film is formed even at the substrate temperature of 67 ° C., and the relative reflectance is 83% or more.

In the present invention, since the recording material is the Sb3Te recording material, it is possible to record at least a recording mark length of 0.1 μm by narrowing the beam system of the recording laser light. As the recording state stabilizing material in the present invention, group 4 elements, group 1B elements and group 3 elements are effective. Ge is most effective, Cu, In, B
Is also effective. In addition, N of group 5 is also effective for stabilizing the recording state. As the crystallization promoting material, Group 5 elements and Group 6 elements are effective. Particularly, Sb, Bi, and Te are effective.

The crystallization promoting layer contains at least one of the recording state stabilizing material, the crystallization promoting material, and the high linear velocity material. The most preferable crystallization promoting layer is
It is a layer composed of binary elements of Bi and Ge. Further, a further impurity element may be added to the crystallization promoting layer in order to adjust the melting point. Materials that can be used as impurity elements are A
g, Cd, Ce, Co, Cr, Fe, H, Hg, Ir,
K, La, Li, Mo, Na, Ni, O, P, Pb, P
d, Po, Pr, Pt, Pu, Rb, Rh, Ru, S,
Se, Si, Sn, Sr, Th, Ti, Tl, U, Cl
And Br and the like.

The crystallization promoting layer does not have to be a completely continuous thin film on the substrate. That is, when the film thickness of the deposited film is about 1 nm in terms of the mass film thickness, a large number of discontinuous islands are formed. When the film thickness increases, the islands are connected to each other,
It becomes a perfect thin film on the substrate. In the present invention, the island shape is also referred to as a crystallization promoting layer in a microscopic sense.

An example of the optical information recording medium according to the present invention is shown in FIG. (1) is a substrate, (2) is a first dielectric layer, (3) is a crystallization promoting layer, (4) is a recording layer, (5) is a second dielectric layer, and (6) is reflected heat radiation. The layer (7) is an organic protective layer provided on the reflection / heat dissipation layer as needed.
In the figure, only the information substrate side of the optical information recording medium is shown. In most cases, the substrate material is polycarbonate. When the substrate thickness is 1 mm or more,
After forming the layer of FIG. 1 on a substrate of about 0.6 mm, another layer of 0.
In some cases, a 6 mm substrate may be bonded to have a thickness of about 1.2 mm, and the tolerance of the substrate thickness in the present invention is ± 0.3 mm when the thickness is 2.0 mm or more, and ± 0.2 when the thickness is 1.0 mm.
mm and ± 0.2 mm for 0.6 mm thickness. Grooves are formed on the substrate, and the depth is 200Å to 450
It is about Å. The groove pitch is 0.74 μm when used as a DVD compatible medium. This pitch is 0.
When miniaturized to about 3 μm, by using a blue light emitting laser, 20 GB on a disk with a radius of 120 mm
The above recording is possible.

In the present invention, SiOx, ZnO, SnO ₂ and Al are used as the first and second dielectric layers.
₂ O ₃ , TiO ₂ , In ₂ O ₃ , MgO, ZrO ₂ , T
a ₂ O _{5 and} other metal oxides, Si ₃ N ₄ , AlN, Ti
N, BN, ZrN and other nitrides, ZnS, TaS _{4 and} other sulfides, SiC, TaC, B ₄ C, WC, TiC, ZrC
And the like. These materials can be used alone as the protective layer or as a mixture. For example, as a mixture, ZnS and Si
Ox, like _Ta 2 _{O 5} and SiOx it is.

The thickness of the first dielectric layer is 50 to 250 n.
A range of m is preferred. When the thickness is less than 50 nm, it is not preferable because the environment resistance protection function is lowered, the heat resistance is lowered, and the heat storage effect is lowered. A thickness of more than 250 nm is not preferable because in the film forming process by the sputtering method or the like, film temperature rises to cause film peeling or cracks and decrease in sensitivity during recording. The thickness of the second dielectric layer is 15 to 50.
nm is preferred. In the case of the second dielectric layer, if it is thinner than 10 nm, the heat resistance is lowered, which is not preferable. Conversely, 100 nm
If it exceeds, the recording sensitivity will decrease and the film will peel off due to temperature increase.
Repeated overwrite characteristics deteriorate due to deformation and deterioration of heat dissipation.

As the reflection / heat dissipation layer (6), Al, Au,
Cu, Ag, Cr, Sr, Zn, In, Pd, Zr, F
e, Co, Ni, Si, Ge, Sb, Ta, W, Ti,
A simple substance or an alloy of a material mainly composed of a metal such as Pb can be used. It is important that this layer efficiently dissipate heat, and the film thickness is preferably 50 to 160 nm. If the film thickness is too thick, the heat dissipation efficiency is too high and the sensitivity is poor, and if it is too thin, the sensitivity is good but the repetitive overwrite property is poor. The characteristics are required to be high in thermal conductivity, have a high melting point, and have good adhesion to the protective layer material.

FIG. 2 shows an example in which substrates having a thickness of about 0.6 mm are attached and used. The dielectric material, the crystallization promoting material, the recording material, and the reflection / heat dissipation material are the same as in the case of FIG. In the case of FIG. 2, the transmissivity of the semitransparent reflective heat dissipation layer (13) and the first recording layer (11) is set to 50% or more.

FIG. 3 shows a case where two recording layers are provided on a substrate having a thickness of about 1 mm. The dielectric material, the crystallization promoting material, the recording material, and the reflection / heat dissipation material are the same as in the case of FIG. In the case of FIG. 3, in order to adjust the transmittance of the first recording layer, the first dielectric layer of (22) and the (2)
The second dielectric layer 5) may have a multi-layered structure of different materials.

In order to perform optical recording on such an optical information recording medium of the present invention, in the case of forming an amorphous corresponding to a reference clock length of n cycles, (n-1) laser pulse irradiation is performed in a time of n cycles. Do. For example, when forming an amorphous material having a length corresponding to 5 cycles of the reference clock shown in FIG. 4, laser pulse irradiation is performed 4 times. In the case of recording at a recording linear velocity of 8.5 m / s and a reference clock of 63.7 MHz (DVD, 2.4 × speed recording), for example, the laser irradiation start delay time is 19 ns, the head pulse width is 6 ns, and the multi-pulse is shown in the figure. Width 7ns, cooling pulse width 14.5ns, recording power 15mW,
The erasing power is 8 mW and the cooling power is 0.1 mW.

The optical information recording medium having the above materials and structure can be recorded / reproduced by using a semiconductor laser having a wavelength of 635 or 650 nm and a pickup of NA 0.6. As a recording method, for example, Pulse
Width Modulation and modulation code is EFM or EFM +
The [8 / 16RLL (2,10)] method or the like can be used. In this case, the pulse is divided into the head pulse and the subsequent multi-pulse part. The multi-pulse part is for repeating heating and cooling. In this case, the relationship between the respective powers is heating (recording) power> erasing power> cooling power, and the cooling power is reduced to about the reading power. Usually, the linear velocity is 3.5 to 8.5 m / s, and the read power is 1 mW or less.

[0025]

EXAMPLES The present invention will be described below based on examples.
The following thin films (1) to (5) are formed on a polycarbonate substrate (hereinafter referred to as a PC substrate) having a thickness of 0.6 mm and a diameter of 5 inches by a sputtering method. (1) First dielectric layer: ZnS.SiO2 (target molar ratio 79.5: 20.5); film thickness 220 nm. (2) Crystallization promoting layer: A target made of a recording state stabilizing material, a crystallization promoting material, and a high linear velocity material was used. The composition and film thickness are shown in Table 1. (3) Recording layer: An alloy target of Sb3Te-based material was used. The composition is shown in Table 1. Film thickness 16 nm. (4) Second dielectric layer: ZnS.SiO ₂ (mol% ratio of target: 79.5: 20.5); film thickness 10 nm. (5) Reflective heat dissipation layer: AlTi; film thickness 140 nm. The substrate temperature at the time of forming the recording layer was set to a temperature at which the polycarbonate substrate did not plastically deform. In this case, the IR lamp output is controlled so that the thermocouple brought into contact with the substrate has a temperature of 100 ° C., and the substrate is transported to the recording layer film forming chamber after the monitor temperature by the thermoelectric element is stabilized. The substrate temperature in the recording layer deposition chamber was 67 ° C. when measured. After completion of the film formation, a UV curable resin was spin-coated and then cured by irradiation with UV light. The substrate manufactured in this way
It was bonded to another substrate having a thickness of 0.6 mm to have a thickness of about 1.2 mm.

A recording linear velocity of 8.5 and 14 m / s was obtained using a pickup head having a wavelength of 660 nm and an NA of 0.65.
Recording was performed at a speed corresponding to a recording density of 4.7 GB on a disk having a diameter of 120 mm. Even when writing one mark, recording was performed by a multi-pulse method in which laser irradiation and cooling were repeated. Amorphous marks having a length that is a multiple of one clock cycle are formed, but laser irradiation and cooling are performed the same number of times as the clock frequency per mark length. The optimum ratio of the laser irradiation power (recording power) for forming the amorphous mark and the power (erasing power) for forming the crystal space depends on the film thickness and material of the crystallization promoting layer, and is (recording power) / (erasing power). Power) = 0.4 to 0.6.

In the recording characteristics, the jitter is a value obtained by dividing the standard deviation of the read time deviation at the boundary between the recording mark and the space by one read clock cycle time (unit:%).
The modulation is a value obtained by dividing the amplitude of 14T by the reflectance of 14T.

(Examples 1-8, Comparative Examples 1-2) Example 1
8 and Comparative Examples 1 and 2, repeated recording evaluated by media reflectance and relative reflectance immediately after production, recording linear velocity 8.5, and speed of 14 m / s (linear velocity DVD 2.5, equivalent to 4 × velocity). Jitter characteristics, recording jitter is 1 when stored at 80 ℃
% Rise time was evaluated. The results are shown in Table 2. Here, the relative reflectance is a measure of the degree of crystallization progress at the film forming stage and is defined by the following formula.

[0029]

[Equation 1] Relative reflectance = (media reflectance before recording) / (reflectance of molten recrystallization formed during recording) × 100 (%)

According to the knowledge obtained by the inventor, if it is less than 80%, the media reflectivity fluctuates with recording, and good media characteristics cannot be obtained.

As a result of evaluation, in Examples 1 to 8,
The media reflectance was 20% or more, the relative reflectance was 80% or more, and the storage reliability was 100 hours, and the storage reliability was good. Further, the repetitive recording jitter characteristics at the recording linear velocity of 8.5 and the speed of 14 m / s were less than 10% in both the first recording and the 1,000-time recording, showing good characteristics.

On the other hand, in Comparative Example 1, the storage reliability was good, and the repetitive recording jitter characteristic at the recording linear velocity of 8.5 m / s was 1 in both the first recording and the 1000th recording.
It was less than 0% and showed good characteristics, but the repeated recording jitter characteristic at a recording linear velocity of 14 m / s was 100% for the first time.
Both recordings were 0%, which exceeded 15%, which was a very bad characteristic. This is considered to be due to insufficient speeding up of the recording material because there is no material for increasing the linear velocity.

In Comparative Example 2, the repetitive recording jitter characteristics at the recording linear velocities of 8.5 and 14 m / s were less than 10% in both the first recording and the 1000th recording, which was a good characteristic. However, the storage reliability was very poor. It is considered that this is because the storage reliability was lowered because the proportion of Sb was increased to increase the recording layer material speed.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

As is apparent from the detailed and specific description above, according to the present invention, it is possible to manufacture an Sb ₃ Te-based recording material phase change recording medium without initialization, so that the DVD-
It has an extremely excellent effect that an initialization-less medium having a recording density of 4.7 GB / 120 mm diameter disc or more, which is ROM compatible, can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an optical information recording medium according to the present invention.

FIG. 2 is another diagram showing an example of the optical information recording medium according to the present invention.

FIG. 3 is still another diagram showing an example of the optical information recording medium according to the present invention.

FIG. 4 is a diagram showing an example of a recording mode for an optical information recording medium of the present invention.

[Explanation of symbols]

1 substrate 2 First dielectric layer 3 Crystallization promotion layer 4 recording layers 5 Second dielectric layer 6 Reflective heat dissipation layer 7 protective layer 8 substrates 9 First dielectric layer 10 Crystallization promotion layer 11 First recording layer 12 Second dielectric layer 13 Semi-transparent reflective heat dissipation layer 14 Protective layer 15 Third dielectric layer 16 Second recording layer 17 Crystallization promotion layer 18 Second dielectric layer 19 Reflective heat dissipation layer 20 substrates 21 cover layer 22 First Dielectric Layer 23 Crystallization promoting layer 24 First recording layer 25 Second dielectric layer 26 Protective layer 27 Third Dielectric Layer 28 Second recording layer 29 Crystallization promoting layer 30 Fourth dielectric layer 31 Reflective heat dissipation layer 32 substrates

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoto Shibata             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Masato Hariya             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Katsunari Hanaoka             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 2H111 EA04 EA12 EA23 EA32 EA33                       FA01 FA11 FA23 FB05 FB09                       FB12 FB30                 5D029 JA01 JB03 JB05 JC09

Claims (9)

[Claims] 1. A recording layer which, in addition to Sb and Te, contains substantially no other element or contains at least one kind of element belonging to Group I to Group VII of the periodic table, and the remaining layer. In the optical recording medium having, the remaining layer contains a high linear velocity material, and the optical information medium is irradiated with energy to perform a recording operation, whereby the recording layer in the recording layer is completed at the end of the film forming process. The phase change recording medium in which the amount of the above-mentioned other element existing in the other layer migrates and exists in the recording layer from the other layer. 2. The recording layer contains Sb and Te which is 1/3 or less of Sb in atomic number, and has a Ge content of 0 to less than 5 atomic%. The described phase change recording medium. 3. The phase change recording medium according to claim 1, wherein the other layer is a crystallization promoting layer containing a recording state stabilizing material and a crystallization promoting material. 4. The recording state stabilizing material is a Group 4 element,
The phase change recording medium according to claim 3, wherein the phase change recording medium is a Group 1B element, a Group 3 element, and / or a Group 5 element. 5. The recording state stabilizing material is Ge, C
The phase change recording medium according to claim 4, wherein the phase change recording medium is u, In, B and / or N. 6. The high linear velocity material is Ga, Dy, Ca,
The phase change recording medium according to claim 3, wherein the phase change recording medium is at least one element selected from the group consisting of Mg and Mn. 7. The high linear velocity material is Ga or / and M
7. The phase change recording medium according to claim 6, wherein the phase change recording medium is n. 8. The phase change recording medium according to claim 3, wherein the crystallization promoting material is a Group 5 element or a Group 6 element. 9. The phase change recording medium according to claim 8, wherein the crystallization promoting material is Sb, Bi and / or Te.