JP4063499B2 - Optical information recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium, and more particularly to a phase-change optical information recording medium that can be rewritten without an initialization process.
[0002]
[Prior art]
As an optical information recording medium capable of recording, reproducing and erasing information by laser beam irradiation, there is a phase change type optical information recording medium using a reversible phase change between a crystalline state and an amorphous state. Commercialization as media such as RAM, -RW, and + RW is expected.
[0003]
Among the recording layer materials of the phase change optical information recording medium, those widely known at a practical level include GeTe-Sb.₂Te_ThreeHaving a pseudo binary system composition of Ge₂Sb₂Te_FiveGe-Te-Sb ternary alloy materials represented by the following (hereinafter referred to as Ge-Te-Sb alloy), and Sb-Sb₂Te_ThreeThere are AgInSbTe-based materials represented by AgInSbTe. In recent years, regarding the AgInSbTe-based material, although the SbTe composition is in the vicinity of the SbTe eutectic composition and is not different from the conventional AgInSbTe-based material, the metastable Sb belonging to the space group Fm3m._ThreeThose having a new crystal structure characteristic of having a Te phase have been developed as those having excellent high-density recording and repetitive characteristics (Japanese Patent Laid-Open No. 2000-43415, etc., hereinafter referred to as metastable Sb)._ThreeSbTe-based alloy having a Te phase). That is, metastable Sb_ThreeA Te skeleton is used as a basic skeleton, and at least one additive element such as Ag, In, Ge is added according to the need for improving characteristics, and it is represented by AgInSbTe, AgInSbTeGe, InSbTeGe, GeSbTe, and the like. .
[0004]
Ge-Te-Sb alloys and metastable Sb_ThreeWhen comparing with a SbTe alloy having a Te phase, the constituent elements are the same or similar at first glance. For example, metastable Sb_ThreeWhen the additive element for the SbTe-based alloy having the Te phase is Ge, the constituent elements are three elements of Ge, Sb, and Te, and the constituent elements are exactly the same. However, in reality, the difference in physical properties is very large because the composition ratio of SbTe is greatly different, and so on, so far, development has been carried out with different approaches as fundamentally different material systems.
[0005]
That is, Ge—Te—Sb alloy material and metastable Sb_ThreeThe SbTe-based material having a Te phase has the following differences. For example, first, the former is GeTe-Sb in composition.₂Te_ThreeWhile the latter is regarded as a pseudo binary alloy, the latter is Sb-Sb.₂Te_ThreeIt is considered as a pseudo binary alloy. Second, in the phase change between crystal and amorphous, in the former, the three elements Ge, Sb, and Te form the basic skeleton of the crystal structure, and these three elements are essential for good recording / reproducing operation. On the other hand, in the latter, the Sb and Te two elements form a basic skeleton of the crystal structure, and basically a good recording / reproducing operation is possible with only the two elements. Thirdly, in the crystal structure change when the recording layer thin film in the amorphous state is heated, the former causes two phase changes in the order of the face-centered cubic lattice crystal structure and the hexagonal crystal structure. In contrast, the latter causes only a single phase change (becomes either a face-centered cubic lattice crystal structure or a rhombohedral crystal structure). Fourth, in the crystallization at the time of melt recrystallization (erasing), the former is said to be based on uniform nucleation in which nucleation occurs in the amorphous mark, whereas the latter is based on the erasing portion (crystal Part) and the amorphous mark.
[0006]
The inventors have heretofore described that the latter material system, that is, metastable Sb among the phase change optical information recording media described above._ThreeResearch and development have been made on materials composed of SbTe-based materials having a Te phase (Japanese Patent Laid-Open No. 2000-43415, etc.). This metastable phase is different from the recording layer of the SbTe eutectic structure, and Sb and Sb₂Te_ThreeAnd the recording mark is not disturbed due to the crystal grain boundary. Therefore, the metastable Sb_ThreeThose using a recording layer characterized by having a Te phase have the advantage that high-density recording is possible.
[0007]
By the way, in the above-described phase change optical information recording medium, the recording layer is formed by a vacuum film forming method such as sputtering or vapor deposition, and the film 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 recording carrier using phase change, the recording film is generally set in an amorphous state in a recorded state and in a crystalline state in an erased (initialized) state. For this reason, it is necessary to perform an initialization process for crystallizing the recording layer by performing a heat treatment such as laser beam irradiation after the recording layer is formed.
[0008]
However, since the initialization process requires more than 30 seconds, the throughput is reduced, and in the case of mass production, many devices for the initialization process are required, resulting in high equipment costs. There is a disadvantage that the product cost increases.
[0009]
Under these circumstances, some efforts have been made to shorten the process time of the initialization process. As one of them, a crystallization auxiliary layer (JP-A-5-342629, JP-A-9-161316) for assisting crystallization of the recording layer, or a crystallization promoting layer (WO98) for promoting crystallization of the recording layer. No. 47471, Japanese Patent Laid-Open No. 11-96596) is previously provided immediately below the recording layer, so that the recording layer is crystallized in the film forming stage, thereby eliminating the need for an initialization process or shortening the time. Yes. Among these methods, the technique described in WO 98/47142 is particularly noted in that the initialization can be basically made unnecessary.
[0010]
According to the invention described in WO 98/47142, in a method for manufacturing an optical information recording medium having a recording layer made of a material mainly composed of Ge, Sb, and Te, a crystallization promoting layer (for example, Sb, A layer made of a material containing at least one of Bi, Sb compound and Bi compound) is formed, and a recording layer is formed immediately above this, whereby the recording layer can be crystallized in the film forming stage. Thus, an optical information recording medium that does not require initialization can be realized. It is disclosed that stable recording characteristics can be obtained with respect to CNR and erasure ratio only.
[0011]
However, in the invention described in WO 98/47142, the recording layer made of a material mainly composed of Ge, Sb, and Te is a “face-centered cubic lattice system” when the temperature is raised from an amorphous state. Since it is described as causing a phase change in the order of crystal structure and hexagonal crystal structure, it refers to a Ge—Te—Sb alloy. Therefore, WO 98/47142, when combined with what is described below, is metastable Sb_ThreeIt cannot be said that a method that eliminates the need for an initialization step for a medium having an SbTe-based material having a Te phase as a recording layer is disclosed.
[0012]
That is, according to the knowledge of the present inventors, the method using the crystallization promoting layer has a large adverse effect on the media properties exerted by the material of the crystallization promoting layer, so that the quality cannot be ensured and consequently the manufacturing cost cannot be reduced. Has the problem. In particular, a decrease in storage reliability becomes a serious problem. This is because the crystallization promoting layer melts at the time of recording and does not exist as a layer, but remains dispersed in some form in the amorphous recording mark and functions as a crystallization nucleus during storage, so that amorphous recording This is considered to promote the crystallization of the mark. Therefore, in the method using the crystallization promoting layer, it is desirable to use a recording layer material that is easily crystallized from the viewpoint of facilitating crystallization at the film forming stage. On the other hand, when a recording material that is difficult to crystallize and has high reliability is used, crystallization at the film forming stage becomes difficult even if the storage reliability can be ensured. In other words, after all, the method using the crystallization promoting layer must satisfy the conflicting requirements of promoting the crystallization of the recording material in the film forming stage and ensuring the reliability of the amorphous recording mark (inhibition of crystallization). It has the difficulty of having to.
[0013]
On the other hand, in this respect, WO98 / 47142 discloses only an example of CNR and erasure ratio, but it is disclosed as an example that stable recording characteristics can be obtained, but reliability is not sufficiently disclosed, It is disclosed that the case where the atomic ratio of Ge in the recording layer is less than 10 atom% is not preferable in terms of reliability.
[0014]
That is, from the viewpoint of storage reliability, the Ge addition amount is preferably 10 atom% or more, but metastable Sb_ThreeIn the case of an SbTe system having a Te phase, according to the knowledge of the present inventors, the amount of Ge needs to be less than 10 atom%. This is because when the amount of Ge added exceeds 10 atom%, metastable Sb_ThreeTe phase formation becomes difficult, and metastable Sb_ThreeThis is because even if the Te phase is formed, there is an experimental fact that high-density recording cannot be performed satisfactorily. In other words, metastable Sb_ThreeIn an SbTe system having a Te phase, the amount of Ge added must be less than 10 atom%. This is because the Ge—Te—Sb-based alloy material forms a basic skeleton when Ge itself undergoes a phase change between crystal and amorphous, whereas metastable Sb._ThreeIn SbTe-based materials having a Te phase, it is considered that this is due to a fundamental difference between the two material systems, in which Ge is only present as a trace additive element._ThreeIn a SbTe-based material having a Te phase, it is expected that it is very difficult to achieve both crystallization during film formation and maintenance of reliability in a method using a crystallization promoting layer.
[0015]
For this reason, metastable Sb_ThreeIn order to find an optimum recording material in the SbTe-based material system having a Te phase, it is necessary to study a huge number of combinations in order to realize an optical information recording medium that does not require initialization, and a great deal of labor is required. It is expected that.
[0016]
In view of the circumstances as described above, the metastable Sb based on the invention described in WO 98/47142._ThreeIt is not easy to make the initialization process unnecessary with an SbTe-based material having a Te phase, and a dramatic advance in technology is required. Furthermore, the invention described in WO 98/47142 based on Ge—Te—Sb-based alloys recognizes these problems and is metastable Sb._ThreeIt is considered that the SbTe system having a Te phase is intentionally excluded, or conversely, these problems are not recognized at all and no solution is disclosed.
[0017]
Although the problem of storage reliability is considered to occur in the same manner based on JP-A-9-161316 and JP-A-5-342629, no specific solution to the problem is disclosed. Absent. Therefore, it is still not easy to eliminate the initialization process based on Japanese Patent Application Laid-Open Nos. 9-161316 and 5-342629.
[0018]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a metastable Sb provided with a crystallization promoting layer._ThreeIn an optical information recording medium having an SbTe-based recording material having a Te phase, high-density optical information that requires both crystallization of the recording layer at the film forming stage and storage reliability of the medium as a product, and does not require initialization. It is to provide a recording medium.
[0019]
[Means for Solving the Problems]
  The above problem is (1) “accelerating crystallization in an optical information recording medium in which at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, and a reflective layer are laminated on a substrate. LayerIt consists of Bi alone and the layer thickness is 0.4nm or moreThe recording layer has a metastable Sb3Te phase composed mainly of Sb, Te and a space group of Fm3m, is doped with Ge, Ge and In, and has a crystallization temperature (Tc) of 145. Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atom composition (γ atom) in the average composition of the recording layer and the crystallization promoting layer. %)), An optical information recording medium characterized in that α + 0.7β ≧ γ holds ”, (2)“ at least a first protective layer, a crystallization promoting layer, a recording layer on a substrate ” In the optical information recording medium in which the second protective layer and the reflective layer are laminated, the crystallization promoting layer isIt consists of Bi alone and the layer thickness is 0.4nm or moreThe recording layer has a metastable Sb3Te phase composed mainly of Sb, Te and a space group Fm3m, and is doped with Ge, Ge and In, and has an Sb composition ( δ) and Te composition (ε) are atomic ratios (%) in the range of 55 ≦ δ ≦ 85, 10 ≦ ε ≦ 35 (where δ + ε <100), and the crystallization temperature (Tc) is 145 Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atom composition (γ atom) in the average composition of the recording layer and the crystallization promoting layer. %)), An optical information recording medium characterized in that a relationship of α + 0.7β ≧ γ holds ”, (3)“Recording layer I group b element, II Group elements, III Group elements, IV Group elements, group V elements, VI It has at least one element selected from group elements, rare earth elements and transition metal elementsThe optical information recording medium according to item (1) or (2) ", (4)"I The b group element is Ag.SaidIn item (3)Described optical information recording medium ", (5)"The Ge composition occupying the recording layer is characterized by an atomic ratio of less than 10 atom%Said (1)Term thru (3) Optical information recording medium according to any one of items ", (6)"α> βThe optical information recording medium according to any one of (1) to (5) ”, (7)“The crystallization temperature (Tc) is in the range of 150 ° C. ≦ Tc ≦ 170 ° C.This is achieved by the optical information recording medium according to any one of (1) to (6).
[0020]
The present inventor has been made as a result of intensive studies in order to solve the above-mentioned problems, and has at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, a reflection on the substrate. In the optical information recording medium in which the layers are laminated, the crystallization promoting layer is a material containing Bi atoms, and the recording layer material is composed of Sb and Te as main components and is composed of a metastable Sb composed of the space group Fm3m._ThreeIt has a Te phase, is doped with Ge or Ge and In, has a crystallization temperature in the range of 145 ° C. ≦ Tc ≦ 185 ° C., and the recording layer and the crystallization promotion It is characterized in that a relationship of α + 0.7β ≧ γ is established among Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atom composition (γ atom%) in the average composition with the layer.
That is, in an optical information recording medium in which at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, and a reflective layer are laminated on a substrate, the crystallization promoting layer is a material containing Bi atoms. The recording layer material is composed of Sb and Te as main components and the space group Fm3m._ThreeIt has a Te phase, is doped with Ge or Ge and In, has a crystallization temperature in the range of 145 ° C. ≦ Tc ≦ 185 ° C., and the recording layer and the crystallization promotion Crystallization is promoted by satisfying the relationship of α + 0.7β ≧ γ between Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atom composition (γ atom%) in the average composition with the layer. Metastable Sb with layer_ThreeIn optical information recording media having a recording material having a Te phase, it is possible to achieve both crystallization of the recording layer at the film-forming stage and storage reliability of the medium as a product, and high-density optical information that does not require initialization. A recording medium can be provided.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The optical information recording medium of the present invention is an optical information recording medium in which at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, and a reflective layer are laminated on a substrate. Metastable Sb which is a material containing Bi atoms, and the recording layer material is composed of Sb and Te as main components and the space group Fm3m._ThreeIt has a Te phase, is doped with Ge or Ge and In, has a crystallization temperature in the range of 145 ° C. ≦ Tc ≦ 185 ° C., and the recording layer and the crystallization promotion The relationship of α + 0.7β ≧ γ is established among the Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atom composition (γ atom%) in the average composition with the layer. This optical information recording medium is a phase change type optical information recording medium that performs recording, reproduction, and erasing by utilizing the reversible change of a recording layer between a crystalline state and an amorphous state by laser beam irradiation.
[0022]
Here, Tc means a temperature at which a recording material thin film deposited on a substrate by a vapor deposition method typified by sputtering is crystallized when heated at a rate of temperature increase of 10 ° C./min. This is a measure of the ease of crystallization of the recording material. Specifically, a recording material thin film having a thickness of about 200 nm is deposited on a glass substrate by a sputtering method, and then mechanically scraped off from the substrate to form a thermal analysis called differential scanning calorimetry (DSC). It is measured by the method.
[0023]
According to the knowledge of the present inventors, a lower Tc is desirable from the viewpoint of facilitating crystallization during film formation. In the present invention, by setting Tc to 185 ° C. or less, the recording layer can be crystallized during film formation. Further, crystallization may vary within the substrate surface for each film formation due to variations in the discharge state during recording layer formation, but it is more desirable that the temperature be 170 ° C. or less in order to reduce such variations. The crystallization temperature of the recording material can be adjusted by adding an element such as Ge or In to the SbTe alloy that is the base material of the recording material. Here, according to the knowledge of the present inventor, both Ge and In have an effect of increasing the Tc of the recording material. Further, when the total amount of addition of Ge and In is less than 10%, Tc Increases substantially in proportion to the added amounts of Ge and In, and increases by 5 to 10 ° C. per 1 atom addition.
[0024]
On the other hand, normally, in order to form an amorphous mark during recording, the recording layer is melted by heating to the melting point or higher of the recording layer by laser irradiation. At this time, the crystallization promoting layer is similarly heated. Here, in the case where the crystallization promoting layer is a material containing Bi atoms, since the melting point is usually lower than that of the recording layer, the crystallization promoting layer is similarly melted, and the recording layer and the crystallization promoting layer are mixed with each other. it is conceivable that.
[0025]
That is, it is considered that not only the recording material but also the crystallization promoting layer material exists in the formed recording mark. In such a state, it is considered that the crystallization promoting material mixed with the recording layer serves as a nucleus for crystallization to promote crystallization of the recording mark, resulting in a decrease in reliability of the medium. Therefore, in order to ensure the reliability of the medium, it is necessary to suppress the function of the crystallization promoting material in the recording mark. In the present invention, the quantity relationship between the number of Ge atoms, the number of In atoms, and the number of Bi atoms in the mixed state satisfies a specific relationship, thereby suppressing the influence of the crystallization promoting material existing in the recording mark and recording. The storage reliability in the state (amorphous state) can be ensured. That is, the relationship of α + 0.7β ≧ γ holds among the Ge atom composition (α atom%), In atom composition (β atom%), and Bi atom composition (γ atom%) in the average composition of the recording layer and the crystallization promoting layer. As a result, the influence of the crystallization material present in the recording mark can be suppressed, and the storage reliability in the recording state (amorphous state) can be secured.
[0026]
Here, the relationship between the Ge atom composition (α atom%), the In atom composition (β atom), and the Bi atom composition (γ atom%) in the average composition of the recording layer and the crystallization promoting layer depends on the composition and film thickness of the recording layer. It can be adjusted by setting the composition and film thickness of the crystallization promoting layer. For example, when the film thickness of the crystallization promoting layer is increased, the Bi atom composition (γ atom%) increases, and accordingly, the recording layer is thickened accordingly, or the Ge atom composition (α atom occupying the recording layer composition) %) And increasing the In atom composition (β atom), the above relationship can be maintained. However, if the Ge atom composition (α atom%) and the In atom composition (β atom%) are too large, the crystallization temperature of the recording layer rises and the crystallization temperature exceeds 185 ° C., which is not preferable.
[0027]
On the other hand, when Tc is too low, even if the above relationship is satisfied, a decrease in storage reliability is significant, which is not preferable. In the present invention, as long as the above relational expression is satisfied when Tc ≧ 145 ° C., storage reliability can be ensured. Note that it is desirable that Tc ≧ 150 ° C. when a margin is allowed.
[0028]
The above relational expression is an empirical expression derived on the basis of enormous experimental results, but qualitatively, the following physicochemical interpretation is possible. That is, the above relational expressions Ge and In respectively indicate that they have the effect of suppressing the function of Bi as a crystal nucleus during storage (the side effect of Bi), and the coefficients α and β are respectively It shows the magnitude of efficacy. That is, the Ge1 atom has the effect of suppressing the side effect of Bi1 atom, and the In1 atom has the effect of suppressing the side effect of Bi0.7 atom. In the present invention, the side effect of Bi is suppressed by adjusting the quantity relationship of Ge, In, and Bi based on the above relational expression, and the stability of the amorphous recording mark and thus the storage reliability of the medium are ensured. It became possible. In addition, since Ge and In have a particularly large coefficient for suppressing Bi side effects as compared with other additive elements, Tc can be set in the range of 145 ° C. or higher and 185 ° C. at the same time as Bi side effects are suppressed. The crystallization of the time and the reliability of the medium can both be achieved.
[0029]
In addition, from the above, Ge has a greater ability to suppress side effects of Bi than In. Therefore, when α and β are adjusted in order to satisfy α + 0.7β ≧ γ, it is more preferable that α> β. As a result, the total addition amount (α + β) of Ge and In required to satisfy the relationship of α + 0.7β ≧ γ can be made relatively smaller than when α ≦ β, and recording by adding Ge and In is possible. The increase in the crystallization temperature of the material can be reduced. As a result, the range in which elements other than Ge and In can be added can be expanded, and thus the range of composition selection can be expanded in designing the material.
[0030]
In the present invention, the Sb composition (δ) and the Te composition (ε) in the recording layer are preferably 55 ≦ δ ≦ 85 and 10 ≦ ε ≦ 35 in terms of atomic ratio (%). (Where δ + ε <100). More preferably, 60 ≦ δ ≦ 80, 15 ≦ ε ≦ 30 (where δ + ε <100), and still more preferably 65 ≦ δ ≦ 75, 20 ≦ ε ≦ 30 (where δ + ε <100). .
By setting it in such a range, it is easy to form a metastable Sb3Te phase, and high-density recording is possible.
[0031]
In the present invention, the crystallization promoting layer only needs to contain Bi atoms, and is, for example, Bi alone, Bi alloy (solid solution, intermetallic compound, eutectic, etc.), Bi mixture or the like. Of these, Bi alone or Bi intermetallic compounds are desirable because they can reduce the compositional deviation (compositional deviation between the target composition and the film composition) that occurs during film formation. Note that Bi alone may contain impurities and the like at the time of target fabrication at less than 1 atom%. The composition ratio of Bi in the crystallization promoting layer is usually 5 atom% or more and 100 atom% or less, preferably 25 atom% or more and 100 atom% or less, more preferably 40 atom% or more and 100 atom% or less. Examples of the Bi alloy that can be used in the present invention include an alloy of Bi and Te, an alloy of Bi and Sb, and the like.
[0032]
In the present invention, the crystallization promoting layer may be provided in contact with the entire surface of the recording layer, or may be provided in contact with a part thereof. Even if the crystallization promoting layer is not in contact with the recording layer at all, if the other layer is crystallized, it has an effect as a crystallization promoting layer. The crystallization promoting layer may be provided between the first dielectric layer and the recording layer, may be provided between the recording layer and the second dielectric layer, or may be provided on both of them. Good. From the viewpoint of effectively exhibiting the crystallization promoting action and improving the throughput, it is desirable to provide it between the first dielectric layer and the recording layer. Further, the crystallization promoting layer may be a continuous film or an island-like discontinuous film, and a desired crystallization promoting effect can be obtained. The crystallization promoting layer is formed by a vacuum film forming method such as sputtering or vapor deposition. The thickness of the crystallization promoting layer is preferably 1/100 or more of the recording layer thickness, more preferably 1/50 or more, and even more preferably 1/25 or more.
[0033]
  The film thickness of the crystallization promoting layerIs 0. 4nm or moreGoodPreferably, it is 0.8 nm or more. When the film thickness of the crystallization promoting layer is below the lower limit, the promoting effect is not sufficiently exhibited, which is not preferable. On the other hand, if the crystallization promoting layer becomes too thick, it is difficult to satisfy the relationship 145 ≦ Tc ≦ 185 and the inequality α + 0.7β ≧ γ at the same time. Therefore, the film thickness of the crystallization promoting layer is preferably not more than a value satisfying the above relationship.
[0034]
The recording layer of the optical information recording medium of the present invention has a metastable Sb composed of the space group Fm3m with Sb and Te as main components._ThreeA recording layer having a Te phase is used. As a result, this medium can perform high-density recording. It should be noted that the metastable Sb takes a rhombohedral system slightly distorted from the space group Fm3m._ThreeEven with a recording layer having a Te phase, high-density recording is possible.
[0035]
In addition, if necessary, such as improvement of recording characteristics and improvement of storage reliability, the recording layer may have a group Ib element, group II element, group III element, group IV element, group V element, group VI element, rare earth element and At least one element selected from transition metal elements is added.
The additive element is metastable Sb composed of space group Fm3m._ThreeIt can be added in a range that does not hinder the appearance of the Te phase and that the crystallization temperature is 145 ° C. or higher and 185 ° C. or lower.
[0036]
Ge or Ge and In are added to the recording layer. Ge has a remarkable effect of improving storage reliability and recording characteristics. Further, In has an effect of improving storage reliability and improving recording characteristics at the time of high-speed line recording.
As the addition amount of Ge and In, if the addition amount is too large, Sb_ThreeThis is not preferable because it is difficult to form a Te metastable phase. Therefore, the amount of each added is preferably less than 10 atom%, more preferably less than 7 atom%, and still more preferably less than 5 atom%.
The thickness of the recording layer is usually 10 to 100 nm, preferably 15 to 35 nm, and more preferably 15 to 25 nm. If the thickness is less than 10 nm, the light absorption ability is reduced and the function as a recording layer is lost. If the thickness is more than 100 nm, the transmitted light is reduced, so that an interference effect cannot be expected.
[0037]
An example of an 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 a reflection heat dissipation. (7) is an organic environmental protection layer (UV curable resin layer) provided on (6) as necessary.
[0038]
In the present invention, the first and second dielectric layers (protective layers) (2) and (5) are SiOx, ZnO, SnO.₂, Al₂O_Three, TiO₂, In₂O_Three, MgO, ZrO₂, Ta₂O_FiveMetal oxide such as Si_ThreeN_Four, Nitrides such as AlN, TiN, BN, ZrN, ZnS, TaS_FourSuch as sulfide, SiC, TaC, B_FourCarbides such as C, WC, TiC, ZrC and the like can be mentioned. These materials can be used alone as a protective layer, or can be used as a mixture. For example, as a mixture, ZnS and SiOx, Ta₂O_FiveAnd SiOx. These material properties include thermal conductivity, specific heat, thermal expansion coefficient, refractive index and adhesion to the substrate material or recording layer material, etc., high melting point, low thermal expansion coefficient, and good adhesion. Required. In particular, the second dielectric layer repeatedly affects the overwrite characteristics.
[0039]
The film thickness of the first dielectric layer (2) is preferably 75 nm to 200 nm as a range of 50 to 250 nm. If it is thinner than 50 nm, the environmental resistance protection function is lowered, the heat resistance is lowered, and the animal heat effect is lowered. If it is thicker than 250 nm, it is not preferable because film peeling or cracking occurs due to an increase in the film temperature in the film forming process by sputtering or the like, and the sensitivity during recording is lowered. The film thickness of the second dielectric layer (5) is in the range of 10 nm to 100 nm, preferably 15 nm to 50 nm. In the case of the second dielectric layer, if it is thinner than 10 nm, the heat resistance basically decreases, which is not preferable. If the thickness exceeds 100 nm, the overwrite characteristics are repeatedly deteriorated due to a decrease in recording sensitivity, film peeling due to temperature rise, deformation, and a decrease in heat dissipation.
[0040]
As the reflective heat dissipation layer (6), Al, Au, Cu, Ag, Cr, Sn, Zn, In, Pd, Zr, Fe, Co, Ni, Si, Ge, Sb, Ta, W, Ti, Pb, etc. A simple substance or an alloy of metal-based materials, or a mixture thereof can be used. For example, an AlTi alloy in which Ti is added to Al in the range of 0.1 wt% to 5 wt% can be used. If necessary, a plurality of different metals, alloys or mixtures may be laminated. It is important for this layer to dissipate heat efficiently, and the film thickness is 30 nm to 250 nm, preferably 50 nm to 150 nm. If the film thickness is too thick, the heat dissipation efficiency is too high and the sensitivity becomes poor. If the film thickness is too thin, the sensitivity is good but repeated overwrite characteristics deteriorate. The properties are required to have high thermal conductivity, high melting point, and good adhesion to the protective layer material. From the viewpoint of thermal conductivity, Ag or an Ag alloy is preferable. However, according to the knowledge of the present inventors, the second dielectric layer (5) (for example, ZnS and SiO) containing Ag or Ag alloy for the reflective heat radiation layer (6) and containing sulfur typified by ZnS or the like.₂When the medium is stored for a long period of time, there is a problem that a local decrease in reflectance is observed. Therefore, in order to prevent such inconvenience, SiC, as a blocking layer, is formed between the reflective heat radiation layer (6) made of Ag or an Ag alloy and the second dielectric layer (5) containing sulfur typified by ZnS or the like. SIN, ZnS, ZrO₂It is preferable to provide a sulfur-free layer represented by In this case, SiC is particularly desirable.
[0041]
An optical information recording medium having the above-described material and configuration can be recorded and reproduced using, for example, a pickup with NA of 0.6 with a semiconductor laser with a wavelength of 635 nm or NA of 0.65 with a semiconductor laser with 660 nm. As a recording method, for example, the modulation code is EFM or EFM + [8 / 16RLL (2, 10)] in Pulse Width Modulation. In this case, the pulse is divided into a head pulse and a subsequent multi-pulse part. The multi-pulse part is for repeatedly performing heating and cooling. Groove recording.
In the above case, the relationship between the powers is heating (recording) power> erasing power> cooling power, and the cooling power is reduced to about the reading power. The linear velocity is usually 3.5 m / sec to 8.5 m / sec and the reading power is 1 mW or less, but is not limited to this, and 8.5 m / sec to 8.5 m / sec. There may be a linear velocity exceeding / sec.
[0042]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
A polycarbonate substrate having a diameter of 120 cm and a thickness of 0.6 mm is manufactured by injection molding, and (ZnS) is used as a first protective layer on the substrate.₈₀(SiO₂)₂₀, A crystallization promoting layer (specifically described in the following examples and comparative examples), a recording layer (specifically described in the following examples and comparative examples), and a second protective layer (ZnS)₈₀(SiO₂)₂₀Then, AlTi was formed as a reflective layer by sputtering. In this embodiment, the film was formed by a single wafer type sputtering apparatus having five chambers. The film formation this time was performed with an apparatus having five chambers, but the number of chambers need not be limited to five, and production is possible if the number is five or more. The breakdown of each film formation is shown below.
Deposition chamber 1: ZnS / SiO₂(First dielectric layer)
Deposition chamber 2: Crystallization promoting layer
Deposition chamber 3: Recording layer
Deposition chamber 4: ZnS / SiO₂(Second dielectric layer)
Deposition chamber 5: AlTi (reflective heat dissipation layer)
[0043]
Each film forming condition is shown below.
Deposition chambers 1 and 4
Input power: RF 4kW / 8 inch target
Gas pressure: 2 mTorr
Gas type: Ar
Deposition chamber 2
Input power: DC0.4kW / 8 inch target
Gas pressure: 2 mTorr
Gas type: Ar
Deposition chamber 3
Input power: DC0.4kW / 8 inch target
Gas pressure: 2 mTorr
Gas type: Ar
Deposition chamber 5
Input power: DC5kW / 8 inch target
Gas pressure: 2 mTorr
Gas type: Ar
Further, after applying a UV curable resin on the reflective layer, an organic environmental protection layer was formed by irradiating with UV light, and a phase change disk according to the present invention was produced. The results will be specifically shown below. The recording / reproduction was evaluated by using a pickup head having a wavelength of 660 nm and NA of 0.65, a recording density of 0.267 μm / bit, EFM + modulation method, and groove recording.
[0044]
Example 1
The material of the recording layer is Ge_FourSb₆₈Te₂₈(Tc: 155 ° C.), the film thickness was 20 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 0.4 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis, and were found to be Ge 3.8 atom% and Bi 2 atom%, and the Ge atom composition (α atom%) and In atom composition (β atom%). ) And Bi atom composition (γ atom%), α + 0.7β ≧ γ was established.
The medium having the above structure was evaluated for reflectivity and storage reliability after film formation. Regarding storage reliability, after recording at a recording linear velocity of 3.5 m / s and a recording power of 13 mW, after storing for 100 hours in an atmosphere of 80 ° C. and 85%, at a reproducing linear velocity of 3.5 m / s and a reproducing power of 0.8 mW. Random signal jitter was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0045]
In addition, Tc of the recording layer in Example 1 and Examples 2 to 7 described later was measured as follows. A single film (thickness: 200 nm) of the recording layer was formed on a glass substrate under the same film forming conditions as in the production of the medium of the example. The crystallization temperature was measured by differential calorimetric scanning analysis (using Seiko Electronics Industrial thermal analysis system (EXSTAR6000), differential scanning calorimetry device (DSC220)) for the material that was mechanically powdered and scraped off from the substrate. Asked. At this time, the heating rate during thermal analysis was set to 10 ° C./min.
[0046]
(Example 2)
The material of the recording layer is Ge_5.3Sb₆₈Te_26.7(Tc: 165 ° C.), the film thickness was 20 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 5.0 atom% and Bi 5.0 atom% were obtained, and the Ge atom composition (α atom%) and In atom composition ( The relationship of α + 0.7β ≧ γ was established between β atom%) and Bi atom composition (γ atom%).
The medium having the above structure was evaluated for reflectivity and storage reliability after film formation. Storage reliability was recorded at a recording linear velocity of 3.5 m / s and a recording power of 13 mW, then stored at 80 ° C. in an 85% atmosphere for 100 hours, and then randomly reproduced at a linear velocity of reproduction of 3.5 m / s and a reproduction power of 0.8 mW. The jitter of the signal was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0047]
(Example 3)
The material of the recording layer is Ge_5.3Sb₆₈Te_26.7(Tc 165 ° C.), the film thickness was 19 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 0.4 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 5 atom% and Bi 2 atom% were obtained, and the Ge atom composition (α atom%) and In atom composition (β atom%) and The relationship of α + 0.7β ≧ γ was established between the Bi atom compositions (γ atom%).
The reflectivity and storage reliability after film formation were evaluated. Storage reliability was recorded at a recording linear velocity of 3.5 m / s and a recording power of 13 mW, then stored at 80 ° C. in an 85% atmosphere for 100 hours, and then randomly reproduced at a linear velocity of reproduction of 3.5 m / s and a reproduction power of 0.8 mW. The jitter of the signal was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0048]
Example 4
The material of the recording layer is Ge_2.1In_5.2Sb₇₀Te_22.7(Tc 180 ° C.), the film thickness was 19 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge, In, and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis, and were Ge 2.0 atom%, In 5.0 atom, Bi 5.0 atom%, and the Ge atom composition (α atom%). ) And In atom composition (β atom%) and Bi atom composition (γ atom%), the relationship of α + 0.7β ≧ γ holds.
The medium having the above structure was evaluated for reflectivity and storage reliability after film formation. Storage reliability was recorded at a recording linear velocity of 7.0 m / s and a recording power of 13 mW, then stored at 80 ° C. in an 85% atmosphere for 100 hours, and then randomly reproduced at a reproducing linear velocity of 3.5 m / s and a reproducing power of 0.8 mW. The jitter of the signal was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0049]
(Example 5)
The material of the recording layer is Ge_4.2In_3.2Sb₇₂Te_20.5(Tc 180 ° C.) and the film thickness was 19 nm. The material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge, In, and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, they were 4.0 atom%, In 3.0 atom%, and Bi 5.0 atom%, and the Ge atom composition (α atom %) And In atom composition (β atom%) and Bi atom composition (γ atom%), a relationship of α + 0.7β ≧ γ was established.
The medium having the above structure was evaluated for reflectivity and storage reliability after film formation. Storage reliability was recorded at a recording linear velocity of 7.0 m / s and a recording power of 13 mW, then stored at 80 ° C. in an 85% atmosphere for 100 hours, and then randomly reproduced at a reproducing linear velocity of 3.5 m / s and a reproducing power of 0.8 mW. The jitter of the signal was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0050]
(Example 6)
The material of the recording layer is Ge_7.0Sb₇₀Te_23.0(Tc 185 ° C.), the film thickness was 20 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 6.7 atom% and Bi 5.0 atom% were obtained, and the Ge atom composition (α atom%) and In atom composition ( The relationship of α + 0.7β ≧ γ holds between β atom%) and Bi atom composition (γ atom%).
The reflectivity and storage reliability after film formation were evaluated. Storage reliability was recorded at a recording linear velocity of 7.0 m / s and a recording power of 13 mW, then stored at 80 ° C. in an 85% atmosphere for 100 hours, and then randomly reproduced at a reproducing linear velocity of 3.5 m / s and a reproducing power of 0.8 mW. The jitter of the signal was evaluated.
The reflectivity after film formation was 18% or more, and it was confirmed that the recording layer was crystallized in the film formation stage. Also, the storage reliability was good.
[0051]
(Example 7)
The material of the recording layer is Ge_4.5In_1.5Sb₇₀Te_{twenty four}(Tc 168 ° C.), the film thickness was 20 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge, In, and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, they were Ge 4.3 atom%, In 1.4 atom%, and Bi 5.0 atom%, and the Ge atom composition (α atom %) And In atom composition (β atom%) and Bi atom composition (γ atom%), a relationship of α + 0.7β ≧ γ was established. Moreover, the relationship of a> b was established.
Furthermore, when Ag was added using the recording material as a base material, even when Ag3 atom% was added to the base material, the reflectance after film formation was 18% or more, and a medium with good storage reliability was obtained. It was. At this time, Tc was 178 ° C.
[0052]
In each of the above examples, the crystal structure of the recording layer was analyzed. In any of the examples, the crystal structure belonged to either a face-centered cubic crystal or a rhombohedral crystal structure.
[0053]
Further, the recording marks were observed in each of the above examples. As an example of the result, the case of Example 1 is shown in FIG. It can be seen that the amorphous mark (21) is accurately formed in the groove portion (22). Moreover, although it seems that it originates in the difference in a particle size etc., it turns out that the mode of a crystal | crystallization of a groove part (22) and a land part (23) differs. The crystal of the land portion (23) has a small particle size, whereas the crystal of the groove portion (22) has a large particle size. In Example 1, since the groove recording method (recording method in which recording is performed only on the groove portion of the substrate groove and not on the land portion) is adopted, the crystal of the land portion (23) is precisely at a low temperature in the film forming stage. It is a grown crystal. On the other hand, the crystal of the groove portion (22) is a crystal grown at a high temperature by melting the recording material during recording and reproduction. Such a difference in the appearance of the crystal in the unrecorded area or the appearance of the crystal in the recorded area and the unrecorded area is a feature of the medium according to the present invention.
[0054]
(Comparative Example 1)
The material of the recording layer is Ge₈Sb₇₀Te_{twenty two}(Tc 192 ° C.) and the film thickness was 19 nm. The material of the crystallization promoting layer was Bi, and the film thickness was 1 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis, and were found to be Ge 7.6 atom% and Bi 5 atom%, and the Ge atom composition (α atom%) and In atom composition (β atom%). ) And Bi atom composition (γ atom%), α + 0.7β ≧ γ was established, but Tc was outside the range of 145 ≦ Tc ≦ 185.
When the reflectance after film formation was measured, it was less than 10%, and it was impossible to record and reproduce information without an initialization operation. This is probably because Tc is as high as 192 ° C., so that crystallization was not performed during film formation.
[0055]
(Comparative Example 2)
The material of the recording layer is Ge_FiveIn₁Sb₇₀Te_{twenty four}(Tc 175 ° C.), the film thickness was 19 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 0.3 nm. The content ratios of Ge, In, and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. %) And In atom composition (β atom%) and Bi atom composition (γ atom%), a relationship of α + 0.7β ≧ γ was established. When the reflectance after film formation was measured, it was less than 10%, and it was impossible to record and reproduce information without an initialization operation. This seems to be because although the Tc was kept as low as 175 ° C., the film thickness of Bi was as thin as 0.3 nm, so that the effect of promoting crystallization was insufficient, and crystallization during film formation was not performed. .
[0056]
(Comparative Example 3)
In Example 2, the material of the crystallization promoting layer was Bi, and the film thickness was a) 0.2 nm, b) 0.6 nm, c) 1.0 nm, and 2) 1.3 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. B) Ge 4.8 atom%, In 0.9 atom%, Bi 1.01.0 atom%, b) Ge 4.8 atom %, In 0.9 atom%, Bi 3.0 atom%, c) Ge 4.8 atom%, In 0.9 atom%, Bi 5.0 atom%, d) Ge 4.8 atom%, In 0.9 atom%, Bi 6.4 atom%. Regarding a), b) and c), the Ge atom composition (α atom%), the In atom composition (β atom%) and the Bi atom composition (γ atom%) satisfy the relationship of α + 0.7β ≧ γ. Did not meet. The medium having the above structure was evaluated for reflectivity and storage reliability after film formation. With respect to (a), the reflectivity after film formation was measured to be less than 10%, and it was impossible to record and reproduce information without an initialization operation. For d), the reflectivity after film formation was 18% or more, and the recording layer was crystallized. However, with respect to storage reliability, after recording at a recording linear velocity of 3.5 m / s and a recording power of 13 mW, after storing for 100 hours in an atmosphere of 80 ° C. and 85%, a reproducing linear velocity of 3.5 m / s and a reproducing power of 0.8 mW When the jitter of the 3T signal was evaluated, the recording mark was completely lost. Furthermore, when the evaluation was made again after storage for 10 hours, the record mark was completely lost.
On the other hand, for b) and c), the reflectivity after film formation was 18% or more, and the storage reliability was also good. Therefore, in order to obtain the effect as the crystallization promoting layer, the Bi film thickness is required to be 0.4 nm or more, and in order to achieve both crystallization and storage reliability at the film forming stage, Ge atoms It can be seen that the relationship α + 0.7β ≧ γ needs to be established between the composition (α atom%), the In atom composition (β atom%), and the Bi atom composition (γ atom%).
[0057]
(Comparative Example 4)
The material of the recording layer is Ge_ThreeSb₇₀Te_{twenty two}(Tc 142 ° C.) and the film thickness was 19 nm. The material of the crystallization promoting layer was Bi and the film thickness was 0.4 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 2.8 atom% and Bi 2.0 atom% were obtained, and the Ge atom composition (α atom%) and In atom composition ( The relationship of α + 0.7β ≧ γ was established between β atom%) and Bi atom composition (γ atom%), but Tc was outside the range of 145 ≦ Tc ≦ 185.
This medium was evaluated for reflectivity and storage reliability after film formation. The reflectivity after film formation was 18% or more, and the recording layer was crystallized. However, with respect to storage reliability, after recording at a recording linear velocity of 7.0 m / s and a recording power of 13 mW, after storage for 100 hours in an atmosphere of 80 ° C. and 85%, a reproducing linear velocity of 3.5 m / s and a reproducing power of 0. When the jitter of the 3T signal was evaluated at 8 mW, the recording mark was completely lost. Furthermore, when the evaluation was made again after storage for 10 hours, it was found that the recording mark was completely lost, and the storage reliability was drastically lowered. Since Tc is as low as 145 ° C., the side effect of Bi can no longer be suppressed by Ge, and it seems that the storage reliability is lowered.
[0058]
(Comparative Example 5)
The material of the recording layer is Ge_ThreeZn_ThreeSb₇₀Te_{twenty four}(Tc 175 ° C.), the film thickness was 20 nm, the material of the crystallization promoting layer was Bi, and the film thickness was 1.0 nm. The content ratios of Ge and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 2.8 atom% and Bi 4.5 atom% were obtained, and the Ge atom composition (α atom%) and In atom composition ( The relationship of α + 0.7β ≧ γ was not established between β atom%) and Bi atom composition (γ atom%). When the reflectance after film formation was measured, the reflectance after film formation was 18% or more, and the recording layer was crystallized. However, with respect to storage reliability, after recording at a recording linear velocity of 7.0 m / s and a recording power of 13 mW, after storage for 100 hours in an atmosphere of 80 ° C. and 85%, a reproducing linear velocity of 3.5 m / s and a reproducing power of 0. When the jitter of the 3T signal was evaluated at 8 mW, the recording mark was completely lost. Furthermore, when the evaluation was made again after storage for 10 hours, the record mark was completely lost.
On the other hand, in the recording layer composition, In was added instead of Zn. At this time, Tc was 172 ° C. The content ratios of Ge, In, and Bi in the average composition of the recording layer and the crystallization promoting layer were determined by composition analysis. As a result, Ge 2.8 atom%, In 2.8 atom%, and Bi 4.5 atom% were obtained, and the Ge atom composition (α atom %) And In atom composition (β atom%) and Bi atom composition (γ atom%), a relationship of α + 0.7β ≧ γ was established. When the reflectance after film formation was measured, the reflectance after film formation was 18% or more, and the recording layer was crystallized.
When the reflectance and storage reliability after film formation were evaluated for the medium having the above structure, the reflectance after film formation was 18% or more, the recording layer was crystallized, and the storage reliability was also good. .
[0059]
【The invention's effect】
As described above, as is clear from the detailed and specific description, according to the present invention, the metastable Sb provided with the crystallization promoting layer is provided._ThreeIn an optical information recording medium having an SbTe-based recording material having a Te phase, by adjusting the amount relationship of Ge, In, Bi and optimizing the interaction between the crystallization promoting layer and the recording layer, It achieves both the crystallization of the recording layer at the film stage and the storage reliability of the medium as a product, and provides an extremely excellent effect of providing a high-density optical information recording medium that does not require initialization. is there.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an optical information recording medium according to the present invention.
FIG. 2 is a view showing a result of observation of a recording mark in Example 1.
[Explanation of symbols]
1 Substrate
2 First dielectric layer
3 Crystallization promotion layer
4 Recording layer
5 Second dielectric layer
6 Reflective heat dissipation layer
7 Organic environmental protection layer (UV cured resin layer)
21 Amorphous mark
22 Groove
23 Land

Claims (7)

In an optical information recording medium in which at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, and a reflective layer are laminated on a substrate, the crystallization promoting layer is composed of Bi alone and the layer thickness is 0. .4 nm or more , the recording layer has a metastable Sb3Te phase composed mainly of Sb and Te and a space group Fm3m, and Ge or Ge and In are added, and the crystallization temperature (Tc ) In the range of 145 ° C. ≦ Tc ≦ 185 ° C., and the Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atoms in the average composition of the recording layer and the crystallization promoting layer An optical information recording medium characterized in that a relationship of α + 0.7β ≧ γ is established between compositions (γ atom%). In an optical information recording medium in which at least a first protective layer, a crystallization promoting layer, a recording layer, a second protective layer, and a reflective layer are laminated on a substrate, the crystallization promoting layer is composed of Bi alone and the layer thickness is 0. .4 nm or more , and the recording layer has a metastable Sb3Te phase composed mainly of Sb and Te and composed of the space group Fm3m, and is doped with Ge or Ge and In, and occupies the recording layer. Sb composition (δ) and Te composition (ε) are atomic ratios (%) in the range of 55 ≦ δ ≦ 85, 10 ≦ ε ≦ 35 (where δ + ε <100), and the crystallization temperature (Tc ) In the range of 145 ° C. ≦ Tc ≦ 185 ° C., and the Ge atom composition (α atom%) and In atom composition (β atom%) and Bi atoms in the average composition of the recording layer and the crystallization promoting layer Composition (γ atom The optical information recording medium, wherein the relationship α + 0.7β ≧ γ in which is established between). Recording layer I group b element, II Group elements, III Group elements, IV Group elements, group V elements, VI The optical information recording medium according to claim 1, wherein the optical information recording medium has at least one element selected from a group element, a rare earth element, and a transition metal element. I The optical information recording medium according to claim 3, wherein the group b element is Ag. 5. The optical information recording medium according to claim 1, wherein the Ge composition in the recording layer is less than 10 atom% in terms of atomic ratio . The optical information recording medium according to claim 1, wherein α> β. 7. The optical information recording medium according to claim 1, wherein a crystallization temperature (Tc) is in a range of 150 ° C. ≦ Tc ≦ 170 ° C.

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