JPH08127176A - Information recording thin film, manufacture thereof information recording medium and using method therefor - Google Patents

Abstract

PURPOSE: To rewrite while holding excellent recording and reproducing characteristics by specifying the mean composition of an information recording thin film in its thickness direction. CONSTITUTION: An information recording thin film 3 is formed on a board 1 directly or via a protective layer 2, and information is recorded or reproduced by changing the atomic arrangement generated upon irradiating with an energy beam. The mean composition of the film 3 in the thickness direction is represented by a formula (Gea Sbb Tec )1-d Xd , where X is at least one element selected from a group consisting of Cr, Ag, Ba, Co, Ni, Pt, Si, Sr, Au, Cd, Cu, Li, Mo, Mn, Zn, Al, Fe, Pb, Na, Cs, Ga, Pd, Bi, Sn, Ti, V, In, W and lanthanoid element, a, b, c and d satisfy 0.01<=a<=0.67, 0.01<=b<=0.59, 0.25<=c<=0.97, 0.03<=d<=0.3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording thin film and a method of manufacturing the same, and an information recording medium and a method of using the same, and more specifically, it is obtained by FM-modulating analog signals such as video and audio. An information recording thin film capable of recording or reproducing information or digital information such as computer data, a facsimile signal, a digital audio signal, etc. in real time by an energy beam such as a laser beam or an electron beam, a manufacturing method thereof, and the like. The present invention relates to an information recording medium using an information recording thin film and a method of using the same.

[0002]

2. Description of the Related Art Various principles of recording information on a thin film by irradiating a laser beam are known. Among them, phase transition (also called phase change) of film material, photodarkening, etc.
The one that utilizes the atomic arrangement change by the irradiation of laser light is
Since there is almost no deformation of the thin film, it has an advantage that an information recording medium having a double-sided structure can be obtained by directly bonding two disc members. Further, the GeSbTe-based information recording thin film has an advantage that information can be rewritten.

However, in this type of information recording thin film, 1
When the rewriting is performed a large number of times exceeding 0 ⁵ , a part of the information recording thin film flows, and the rewriting characteristics deteriorate. Therefore, methods for preventing the flow of the thin film have been conventionally studied.

For example, Japanese Unexamined Patent Publication No. 4-228127 discloses a method of preventing the flow of an information recording thin film by forming it into microcells. Also, reference T. Ohta et.
al. "Optical Data Strage", '89 Proc. SPIE, 1078,
27 (1989) discloses a method of preventing the flow of the information recording thin film by making the information recording thin film thinner to lower the heat capacity and thereby increasing the influence of the adhesive force with the adjacent layer. It is disclosed.

[0005]

The above-mentioned conventional information recording thin film has the following problems when it is used as a rewritable phase transition type information recording thin film. That is, the number of rewritable times is not sufficient, the crystallization speed becomes slower as the number of rewritable times increases, the reproduction signal strength becomes insufficient as the number of rewritable times increases, and when recording information including a long recording mark, Due to the segregation of elements in the thin film and the flow of the recording film, it is unavoidable that the reflectance levels at the places where the formation probability of the recording mark is high and at the places where the formation probability of the recording mark is low change in the first several tens of irradiations. Laser light irradiation is required a large number of times (for example, 3000 times) in order to uniformly generate (change) in advance (initialization).

Therefore, an object of the present invention is to achieve good recording / recording.
A large number of times (for example, 10 ⁵
(EN) An information recording thin film capable of being rewritten, a method for manufacturing the same, an information recording medium, and a method for using the same.

Another object of the present invention is to provide an information recording thin film which produces a super-resolution effect and which can be read a large number of times (for example, 10 ⁵ times) while maintaining good reproduction characteristics, and a method for manufacturing the same. And to provide an information recording medium and a method of using the same.

[0008]

[Means for Solving the Problems]

(1) A first information recording thin film of the present invention is for information recording, which is formed on a substrate directly or through a protective layer and records / reproduces information by an atomic arrangement change caused by irradiation of an energy beam. In the thin film, the average composition in the film thickness direction of the information recording thin film is _{expressed by the} general formula (Ge _a Sb _b T
e _c ) _1-d X _d, where X is Cr, Ag, Ba,
Co, Ni, Pt, Si, Sr, Au, Cd, Cu, L
i, Mo, Mn, Zn, Al, Fe, Pb, Na, C
s, Ga, Pd, Bi, Sn, Ti, V, In, W, Z
n and at least one element selected from the group consisting of lanthanoid elements, wherein a, b, c and d
Are 0.01 ≦ a ≦ 0.67 and 0.01 ≦, respectively.
b ≦ 0.59, 0.25 ≦ c ≦ 0.97, 0.03
It is characterized by being in the range of ≤d≤0.3.

The reason that the composition ratios a, b, c and d are limited to the above range is that if a <0.01, the crystallization temperature is too low, and a> 0.67. The reason is that the crystallization speed decreases.

This is because if b <0.01, it is necessary to increase the number of laser irradiations for initialization, and if b> 0.59, the crystallization temperature is too low.

This is because if C <0.25, the C / N at the time of rewriting many times is lowered, and if c> 0.97, the laser irradiation time required for erasing is too long.

This is because if d <0.03, the carrier-to-noise ratio (C / N) of the reproduced signal at the time of rewriting many times is lowered, and if d> 0.3, the erasing ratio is lowered. Because.

In the first information recording thin film of the present invention, a, b and c are each 0.02≤a≤0.1.
9, 0.04 ≦ b ≦ 0.4, 0.5 ≦ c ≦ 0.7
It is preferably in the range of 5.

This is because if a <0.02, the crystallization temperature is too low, and if a> 0.19, a large number of laser irradiations are required for initialization.

If b <0.04, the crystallization temperature is too low, and if b> 0.4, the crystallization temperature is too low.

This is because when C <0.5, the C / N of the reproduced signal at the time of rewriting many times decreases, and c> 0.75.
This is because the laser irradiation time required for erasing is too long.

Further, a, b and c are respectively 0.25 ≦ a ≦ 0.65, 0.01 ≦ b ≦ 0.2,
It is also preferable that the range is 0.35 ≦ c ≦ 0.75.

This is because when a <0.25 or a> 0.65, the difference in reflectance when amorphized is small.

When b ≧ 0.01, the crystallization rate can be increased, and when b> 0.2, c <0.35, or c> 0.75, the difference in reflectance is small. Is.

(2) In the first information recording thin film of the present invention, it is preferable to add Tl (thallium) in addition to the element X. This is because the addition of Tl speeds up the erasing of written information and increases the C / N. In this case, the sum of the added amounts of the element X and Tl is 3% or more,
It is preferably 30 atomic% or less. This is because, within this range, the unerased written information does not become large.

At least one halogen element may be added in place of part or all of Tl, or N (nitrogen) may be added in place of Tl. This is because the number of rewritable times is further improved.

Further, when Se is added in an amount of 3 atomic% or more and 30 atomic% or less in place of Tl while keeping the relative proportions of other elements constant, the effect of improving the oxidation resistance or optimizing the reflectance is obtained. Is obtained.

(3) In the first information recording thin film of the present invention, the average composition of the information recording thin film is the element G
a low melting point component L having a relatively low melting point, which is composed of a simple substance of at least one element selected from e, Sb, Te and X or a compound of these elements, and the elements Ge and S
a low melting point component L and a high melting point component H, which are composed of a simple substance of at least one element selected from b, Te and X or a compound of these elements and have a relatively high melting point. When the average composition with H is represented by the composition formula of L _j H _k , j and k are 0.2 ≦ [k
It is preferable that the composition satisfying the relational expression /(j+k)]≦0.4 is used as the reference composition. This is because if it is within this range, the jitter is small.

In this case, said Ge, Sb, Te and X
The content of each element is preferably within ± 10 atom% with respect to the standard composition determined by the above relational expression. When the change in the content of each element from the standard composition becomes large,
This is because the erasing property deteriorates.

When the low melting point component L is GeSb ₄ Te ₇ and the high melting point component H is Cr ₄ Te ₅ , the above j and k are 0.
It is preferable that the reference composition is a composition that satisfies the relational expression 2 ≦ [k / (j + k)] ≦ 0.3. This is because the jitter is smaller within this range.

In this case, said Ge, Sb, Te and X
The content of each element of ± is relative to the value determined by the above relational expression ±
It is preferably in the range of 10 atom%. This is because the recording / erasing characteristics deteriorate as the change in the content of each element from the standard composition increases.

When the low melting point component L is Ge ₂ Sb ₂ Te ₄ and the high melting point component H is Cr ₄ Te ₅ , the above j and k are
It is preferable that the composition satisfying the relational expression of 0.12 ≦ [k / (j + k)] ≦ 0.22 is used as the reference composition. This is because the jitter is smaller within this range.

In this case, Ge, Sb, Te and X
The content of each element of ± is relative to the value determined by the above relational expression ±
It is preferably in the range of 10 atom%. This is because the recording / erasing characteristics deteriorate when the content of each element changes from the standard composition.

When the low melting point component L is Ge ₂ Sb ₂ Te ₅ and the high melting point component H is Cr ₄ Te ₅ , the above j and k are
It is preferable that the composition satisfying the relational expression of 0.05 ≦ [k / (j + k)] ≦ 0.15 is used as the reference composition. This is because the jitter is small within this range.

In this case, the Cr content is within a range of ± 3 atom% with respect to the reference composition determined by the relational expression, and the Ge, Sb and Te contents are determined by the relational expression. It is preferably within a range of ± 10 atomic% with respect to the composition. This is because the recording / erasing characteristics deteriorate as the content change of each element from the standard composition increases.

The content g of Ge in the low melting point component g
(Atomic%), and k and j are k / (j + k) =
It is preferable to satisfy the relational expression of (2 / g) +0.01.
For the same reason as above, the Ge content is preferably within a range of ± 10 atom% with respect to the reference composition, and more preferably within a range of ± 5 atom%.

(4) The second information recording thin film of the present invention records / reproduces information by a change in atomic arrangement which is formed on a substrate directly or through a protective layer and is caused by irradiation of an energy beam. In the information recording thin film, the average composition in the film thickness direction of the information recording thin film is represented by the general formula (G
e _a Te _c ) _1-d X _d, where X is Cr, Ag, B
a, Co, Ni, Pt, Si, Sr, Au, Cd, C
u, Li, Mo, Mn, Zn, Al, Fe, Pb, N
a, Cs, Ga, Pd, Bi, Sn, Ti, V, In,
W and Zn and at least one element selected from the group consisting of lanthanoid elements, wherein a, c and d are each 0.01 ≦ a ≦ 0.67, 0.2
It is characterized by being in the range of 5 ≦ c ≦ 0.97 and 0.03 ≦ d ≦ 0.3.

The second information recording thin film is obtained by removing Sb from the first information recording thin film (b = 0).
Equivalent to. The reason that the composition ratios a, c and d are limited to the above range is for the same reason as described in (1) above.

The a, c and d are each 0.25
≤ a ≤ 0.65, 0.35 ≤ c ≤ 0.75, 0.03 ≤
More preferably, it is in the range of d ≦ 0.3. The a,
It is preferable to limit c and d to these ranges for the same reason as described in (1) above.

(5) Also in the second information recording thin film of the present invention, as described in (3) above, the average composition of the information recording thin film is from the group consisting of the elements Ge, Te and X. A low melting point component L having a relatively low melting point, which is composed of a simple substance of selected elements or a compound of those elements;
A high melting point component H having a relatively high melting point, which is composed of a simple substance of an element selected from the group consisting of the elements Ge, Te and X or a compound of these elements, and comprises the low melting point component L and the high melting point component H. The average composition with the melting point component H is L _j
When represented by the composition formula of H _k , j and k are 0.0
It is preferable that the reference composition is a composition that satisfies the relational expression 2 ≦ [k / (j + k)] ≦ 0.2.

It is preferable to limit the above [k / (j + k)] to this range for the same reason as described in (3) above.

In this case, the content of each element of Ge, Te and X is ±± with respect to the standard composition determined by the above relational expression.
It is preferably in the range of 10 atom%. For the same reason as described in (3) above.

(6) The third information recording thin film of the present invention records / reproduces information by a change in atomic arrangement formed on a substrate directly or through a protective layer, which is caused by irradiation with an energy beam. In the information recording thin film, the average composition in the film thickness direction of the information recording thin film is represented by the general formula (S
b _b Te _c) is represented by _1-d X _d, wherein X is Cr, Ag, B
a, Co, Ni, Pt, Si, Sr, Au, Cd, C
u, Li, Mo, Mn, Zn, Al, Fe, Pb, N
a, Cs, Ga, Pd, Bi, Sn, Ti, V, In,
Represents at least one element selected from the group consisting of W and Zn and lanthanoid elements, and b, c and d are 0.01 ≦ b ≦ 0.59 and 0.25 ≦, respectively.
It is characterized by being in the range of c ≦ 0.97 and 0.03 ≦ d ≦ 0.3.

The third information recording thin film corresponds to the first information recording thin film except Ge.
The reason that the composition ratios a, c and d are limited to the above range is for the same reason as described in (1) above.

(7) Also in this third information recording thin film, as described in (3) and (5) above, the average composition of the information recording thin film has the low melting point component L and the high melting point component H.
And j and k are 0.05 ≦
A composition satisfying the relational expression [k / (j + k)] ≦ 0.4 is preferably used as the reference composition.

It is preferable to limit the above [k / (j + k)] to this range for the same reason as described in the above (3) and (5).

In this case, the content of each element of Ge, Te and X is ± with respect to the standard composition determined by the above relational expression.
It is preferably in the range of 10 atom%. This is also for the same reason as described in (3) above.

(8) In the first to third information recording thin films, the element X preferably has a concentration gradient in the film thickness direction of the information recording thin film. This is because the effect that the number of laser irradiations for initialization can be reduced can be obtained.

(9) Further, the first to third information recording thin films contain precipitates composed of a high melting point component having a melting point relatively higher than that of the remaining components of the information recording thin film. It is preferable that the object contains the element X. This is because it is possible to prevent the C / N from being rewritten many times.

At least a part of the high-melting point component has a mean film thickness of 1 as a discontinuous film near the light incident side interface of the information recording thin film or near the light incident side opposite interface.
It is preferably present in the range of -10 nm. This is because in this case, the effect that the number of rewritable times is improved is obtained.

The content of the high melting point component preferably changes in the thickness direction of the information recording thin film. This is because the effect that the number of laser irradiations for initialization can be reduced can be obtained.

It is preferable that the content of the high melting point component is changed to 50% near the interface on the light incident side of the information recording thin film and 10% near the interface on the opposite side. This is because the number of laser irradiations for initialization can be reduced while maintaining good rewriting characteristics.

It is preferable that the total number of atoms of the constituent elements of the high melting point component is in the range of 10 to 50% with respect to the total number of atoms of the constituent elements of the information recording thin film. If the sum of the number of atoms is less than 10%, C / N of the rewriting time of many times
This is because the erasing ratio decreases, and when it exceeds 50%, the erasing ratio decreases.

The melting point of the high melting point component is preferably 780 ° C. or higher. This is because the higher the melting point of the high-melting point component, the greater the number of rewritable times.

The difference between the melting point of the high melting point component and the melting point of the remaining component of the thin film is preferably 150 ° C. or more. This is because the number of rewritable times increases as the melting point difference increases.

(10) In the first to third information recording thin films, it is preferable that the high melting point component precipitates are distributed in a granular or columnar shape inside the information recording thin film. This is because the number of rewritable times is improved.

In this case, it is preferable that the maximum outer dimension of the precipitate of the high melting point component in the film surface direction of the information recording thin film is 5 nm or more and 80 nm or less. If the thickness is less than 5 nm, the number of rewritable times is small.
This is because the C / N at the time of rewriting a large number of times is reduced when the value exceeds.

The precipitate of the high melting point component extends columnarly in the film thickness direction from both interfaces of the information recording thin film, and the length of the precipitate in the film thickness direction is 5 nm or more. It is preferably (1/2) or less of the film thickness of the recording thin film. This is because the number of rewritable times is small when the thickness is less than 5 nm.

The precipitate of the high melting point component extends in a columnar shape in the film thickness direction from one interface of the information recording thin film, and the length of the precipitate in the film thickness direction is 10 nm or more. It is preferably equal to or less than the thickness of the recording thin film. 10
This is because the number of rewritable times is small when the thickness is less than nm.

The length of the precipitate of the high melting point component in the thickness direction of the information recording thin film is preferably 10 nm or more and less than or equal to the film thickness of the information recording thin film. This is because the rewritable number is large within this range.

A straight line connecting the centers of two adjacent precipitates of the high melting point component has a length of 20 nm or more passing through a region between the precipitates in the film surface direction of the information recording thin film,
It is preferably 90 nm or less. This is because if it is less than 20 nm, the C / N after rewriting many times decreases.
This is because the number of rewritable times is small when the thickness exceeds 90 nm.

(11) Each of the first to third information recording thin films contains a porous precipitate composed of a high melting point component having a melting point relatively higher than that of the remaining components of the information recording thin film. The residual component may be distributed in the pores of the porous precipitate. Even in this case, the same effect as in the case of the above (10) in which the high melting point component is distributed in a granular or columnar shape can be obtained.

The maximum pore size of the porous precipitates of the high melting point component in the film surface direction of the information recording thin film is 80 n.
m or less, and the maximum wall thickness in the film surface direction of the information recording thin film in the region between the two adjacent holes is 20 nm.
The following is preferable. When the maximum hole size exceeds 80 nm, the number of rewritable times decreases and the maximum wall thickness is 2
This is because if the thickness exceeds 0 nm, the C / N after rewriting many times decreases.

The melting point of the remaining components of the information recording thin film is 6
It is preferably 50 ° C or lower, more preferably 250 ° C or lower. This is because if it is 650 ° C or less, there is a sufficient difference between the melting point of the high melting point component and the melting point, and if it is 250 ° C or less, the sensitivity is further improved.

It is preferable that at least one of the real number part and the imaginary number part of the complex refractive index of the information recording thin film changes by 20% or more with respect to that before irradiation by light irradiation.
This is because the reproduced signal becomes large in this case.

(12) The fourth information recording thin film of the present invention records or reproduces information by a change in atomic arrangement which is formed on a substrate directly or through a protective layer and is caused by irradiation with an energy beam. The information recording thin film contains a precipitate composed of a high-melting point component having a melting point relatively higher than that of the remaining component of the information recording thin film, and the precipitate is distributed in the region composed of the remaining component of the information recording thin film. It is characterized by doing.

(13) In the fourth information recording thin film of the present invention, the maximum outer dimension of the precipitate of the high melting point component in the film surface direction of the information recording thin film is 5 nm or more and 80 n.
It is preferably m or less. If it is less than 5 nm, the number of rewritable times is small, and if it exceeds 80 nm, the C / N after many times of rewriting decreases.

The precipitate of the high melting point component extends in a column shape in the film thickness direction from both interfaces of the information recording thin film, and the length of the precipitate in the film thickness direction is 5 nm or more. It is preferably (1/2) or less of the film thickness of the recording thin film. This is because the number of rewritable times is large within this range.

The precipitate of the high melting point component extends in a columnar shape in the film thickness direction from one interface of the information recording thin film, and the length of the precipitate in the film thickness direction is 10 nm or more. It is preferably equal to or less than the thickness of the recording thin film. This is because the rewritable number is large within this range.

The length of the precipitate of the high melting point component in the film thickness direction is preferably 10 nm or more and less than or equal to the film thickness of the information recording thin film. This is because the rewritable number is large within this range.

The straight line connecting the centers of two adjacent high melting point component precipitates has a length of 20 nm or more, which passes through the region between the precipitates in the film surface direction of the information recording thin film, 9
It is preferably 0 nm or less. This is because the rewritable number is large within this range and the C / N after a large number of rewritings is large.

(14) The fifth information recording thin film of the present invention is formed on the substrate directly or through a protective layer.
In an information recording thin film that records or reproduces information by a change in atomic arrangement caused by irradiation of an energy beam, a porous precipitate composed of a high melting point component having a relatively higher melting point than the remaining component of the information recording thin film is formed. It is characterized in that the residual component of the information recording thin film is distributed in the pores of the porous precipitate.

(15) In the fifth thin film for information recording, the maximum inner dimension in the film surface direction of the thin film for information recording of the pores of the porous precipitate of the high melting point component is adjacent to each other by 80 nm or less. The maximum wall thickness in the film surface direction of the information recording thin film in the region between the two holes is preferably 20 nm or less.

When the maximum inner dimension exceeds 80 nm, the number of rewritable times is small, and when the maximum wall thickness exceeds 20 nm, the C / N after rewriting many times decreases.

The melting point of the remaining components of the information recording thin film is 6
It is preferably 50 ° C or lower, more preferably 250 ° C or lower. This is because if it is 650 ° C or less, there is a sufficient difference between the melting point of the high melting point component and the melting point, and if it is 250 ° C or less, the sensitivity is further improved.

At least one of the real number part and the imaginary number part of the complex refractive index of the information recording thin film is preferably changed by 20% or more with respect to that before irradiation by light irradiation.
This is because the reproduced signal becomes large in this case.

The sum of the number of atoms of the constituent elements of the high melting point component is 10 to the sum of the number of all atoms of the information recording thin film.
It is preferably in the range of 50%. This is because the number of rewritable times is large and the C / N after rewriting many times is large within this range.

The melting point of the high melting point component is preferably 780 ° C. or higher. This is because in this case, it becomes difficult to melt during recording / reproduction.

The difference between the melting point of the high melting point component and the melting point of the remaining component of the information recording thin film is preferably 150 ° C. or higher. This is because in this case, it becomes difficult to melt during recording / reproduction.

(16) In the first to fifth information recording thin films, the element X is preferably Cr. This is because in the initialization process, the recording / erasing characteristics are stabilized by irradiation with laser light a smaller number of times.

The element X is Mo, Si, Pt, C.
It may be one kind selected from the group consisting of o, Mn and W. This is because the recording / erasing characteristics are stabilized by irradiating the laser beam a few times after Cr in the initialization process.

(17) In the first to fifth information recording thin films, the high melting point component may be a compound, a simple element or an alloy. As a preferable example, for example,
Cr ₄ Te ₅ , LaTe ₂ , La ₂ Te ₃ , La ₃ Te ₄ , L
aTe, La ₂ Te ₅ , La ₄ Te ₇ , LaTe ₃ , La ₃ T
e, La ₂ Sb, La ₃ Sb ₂ , LaSb, LaSb ₂ , L
_{a 3 Ge, La 5 Ge 3} , La 4 Ge 3, La 5 Ge 4, La
Ge, La ₃ Ge ₅ , Ag ₂ Te, Cr ₅ Te ₈ , Cr ₂ Te
₃ , CrSb, Cr ₃ Ge, Cr ₅ Ge ₃ , Cr ₁₁ Ge ₈ ,
CrGe, Cr ₁₁ Ge ₁₉ , PtTe ₂ , Pt ₄ Te ₅ , P
t ₅ Te ₄ , Pt ₄ Sb, Pt ₃ Sb ₂ , PtSb, Pt ₃ G
e, Pt ₂ Ge, Pt ₃ Ge ₂ , PtGe, Pt ₂ Ge ₃ ,
PtGe ₃ , NiTe, NiTe _0.85 , NiSb, Ni ₃
Ge, Ni ₅ Ge ₂ , Ni ₅ Ge ₃ , NiGe, CoT
e ₂ , CoSb ₂ , CoSb ₃ , Co ₅ Ge ₂ , Co ₅ G
e ₃ , CoGe, Co ₅ Ge ₇ , CoGe ₂ , Si ₂ Te ₃ ,
_{SiSb, SiGe, CeTe, Ce 3} Te 4, Ce 2 T
e ₃ , Ce ₄ Te ₇ , CeTe ₂ , CeTe ₃ , Ce ₂ Sb,
Ce ₅ Sb ₃ , Ce ₄ Sb ₅ , CeSb, CeSb ₂ , Ce ₃
Ge, Ce ₅ Ge ₃ , Ce ₄ Ge ₃ , Ce ₅ Ge ₄ , CeG
e, Ce ₃ Ge ₅ , Ce ₅ Si ₃ , Ce ₃ Si ₂ , Ce ₅ S
i ₄ , CeSi, Ce ₃ Si ₅ , CeSi ₂ , Cr ₃ Si,
Cr ₅ Si ₃ , CrSi, CrSi ₃ , CrSi ₂ , Co ₃
Si, CoSi, CoSi ₂ , NiSi ₂ , NiSi, N
i ₃ Si ₂ , Ni ₂ Si, Ni ₅ Si ₂ , Ni ₃ Si, Pt ₅
Si ₂ , Pt ₂ Si, PtSi, LaSi ₂ , Ag ₃ In,
Ag ₂ In, Bi ₂ Ce, BiCe, Bi ₃ Ce ₄ , Bi ₃
Ce ₅ , BiCe ₂ , Cd ₁₁ Ce, Cd ₆ Ce, Cd ₅₈ C
e ₁₃ , Cd ₃ Ce, Cd ₂ Ce, CdCe, Ce ₃ In,
Ce ₂ In, Ce _{1 + x} In, Ce ₃ In ₅ , CeIn ₂ , C
eIn ₃ , Ce ₂ Pb, CePb, CePb ₃ , Ce ₃ S
_{n, Ce 5 Sn 3, Ce} 5 Sn 4, Ce 11 Sn 10, Ce 3 S
n ₅ , Ce ₃ Sn ₇ , Ce ₂ Sn ₅ , CeSn ₃ , CeZn,
CeZn ₂ , CeZn ₃ , Ce ₃ Zn ₁₁ , Ce ₁₃ Zn ₅₈ ,
CeZn ₅ , Ce ₃ Zn ₂₂ , Ce ₂ Zn ₁₇ , CeZn ₁₁ ,
Cd ₂₁ Co ₅ , CoGa, CoGa ₃ , CoSn, Cr ₃
Ga, CrGa, Cr ₅ Ga ₆ , CrGa ₄ , Cu ₉ G
a ₄ , Cu ₃ Sn, Cu ₃ Zn, Bi ₂ La, BiLa, B
i ₃ La ₄ , Bi ₃ La ₅ , BiLa ₂ , Cd ₁₁ La, Cd
₁₇ La ₂ , Cd ₉ La ₂ , Cd ₂ La, CdLa, Ga ₆ L
a, Ga ₂ La, GaLa, Ga ₃ La ₅ , GaLa ₃ , I
n ₃ La, In ₂ La, In ₅ La ₃ , In _x La, InL
a, InLa ₂ , InLa ₃ , La ₅ Pb ₃ , La ₄ Pb ₃ ,
La ₁₁ Pb ₁₀ , La ₃ Pb ₄ , La ₅ Pb ₄ , LaPb ₂ ,
LaPb ₃ , LaZn, LaZn ₂ , LaZn ₄ , LaZ
_{n 5, La 3 Zn 22,} La 2 Zn 17, LaZn 11, LaZ
n ₁₃ , NiBi, Ga ₃ Ni ₂ , GaNi, Ga ₂ Ni ₃ ,
Ga ₃ Ni ₅ , GaNi ₃ , Ni ₃ Sn, Ni ₃ Sn ₂ , Ni
₃ Sn ₄ , NiZn, Ni ₅ Zn ₂₁ , PtBi, PtB
i ₂ , PtBi ₃ , PtCd ₂ , Pt ₂ Cd ₉ , Ga ₇ P
t ₃ , Ga ₂ Pt, Ga ₃ Pt ₂ , GaPt, Ga ₃ Pt ₅ ,
GaPt ₂ , GaPt ₃ , In ₇ Pt ₃ , In ₂ Pt, In ₃
Pt ₂ , InPt, In ₅ Pt ₆ , In ₂ Pt ₃ , InP
t ₂ , InPt ₃ , Pt ₃ Pb, PtPb, Pt ₂ Pb ₃ ,
Pt ₃ Sn, PtSn, Pt ₂ Sn ₃ , PtSn ₂ , PtS
n ₄ , Pt ₃ Zn, PtZn ₂ , AlS, Al ₂ S ₃ , Ba
S, BaC ₂ , CdS, Co ₄ S ₃ , Co ₉ S ₈ , CoS,
CoO, Co ₂ O ₄ , Co ₂ O ₃ , Cr ₂ O ₃ , Cr ₃ O ₄ , C
rO, CrS, CrN, Cr ₂ N, Cr ₂₃ C ₆₃ , Cr ₇ C
₃ , Cr ₃ C ₂ , Cu ₂ S, Cu ₉ S ₅ , CuO, Cu ₂ O,
In ₄ S ₅ , In ₃ S ₄ , La ₂ S ₃ , La ₂ O ₃ , Mo ₂ C,
MoC, Mn ₂₃ C ₆ , Mn ₄ C, Mn ₇ C ₃ , NiO, Si
_{S 2, SiO 2, Si 3} N 4, Cu 2 Te, CuTe, Cu 3
Sb, Mn ₂ Sb, MnTe, MnTe ₂ , Mn ₅ Ge ₃ ,
Mn ₃ . ₂₅ Ge, Mn ₅ Ge, Mn ₃ Ge ₂ , Ge ₃ W, T
e ₂ W, AlSb, Al ₂ Te ₃ , Fe ₂ Ge, FeG
e ₂ , FeSb ₂ , Mo ₃ Sb ₇ , Mo ₃ Te ₄ , MoT
e ₂ , PbTe, GePd ₂ , Ge ₂ Pd ₅ , Ge ₉ P
d ₂₅ , GePd ₅ , Pd ₃ Sb, Pd ₅ Sb ₃ , PdSb,
_{SnTe, Ti 5 Ge 3, Ge} 31 V 17, Ge 8 V 11, Ge 3
V ₅ , GeV ₃ , V ₅ Te ₄ , V ₃ Te ₄ , ZnTe, Ag ₂
Se, Cu ₂ Se, Al ₂ Se ₃ , InAs, CoSe,
Mn ₃ In, Ni ₃ In, NiIn, Ni ₂ In ₃ , Ni ₃
Examples include high melting point compounds containing the element X, such as In ₇ , PbSe, and high melting point oxides of the constituent elements of these high melting point components.

In addition, it may have a composition close to that of the high melting point compound containing the element X mentioned here, a mixed composition of these compounds, or a compound of three or more elements close to the mixed composition.

Among the high melting point compounds containing these elements X, Cr ₄ Te ₅ , CrSb, LaSb, CoSb, Cr
₃ Te ₄ , LaTe ₃ , Cr ₂ Te ₃ , Cr ₃ Te ₄ , CoT
e, Co ₃ Te ₄ , Cu ₂ Te, CuTe, Cu ₃ Sb, M
Particularly preferred are nTe, MnTe ₂ , and Mn ₂ Sb. In the initialization process, recording with fewer times of laser light irradiation
This is because the erase characteristic is stable.

The content of oxides, sulfides, nitrides, and carbides contained in the high melting point component precipitates is preferably less than 40 atom% of the high melting point component, and preferably less than 10 atom%. More preferable. This is because if it is less than 40 atomic%, an increase in noise can be prevented, and if it is less than 10 atomic%, the noise can be kept even lower.

(18) In the first to fifth information recording thin films, the residual component is, for example, Bi or S.
n, Pb, Sb, Te, Zn, Cd, Se, In, G
a, S, Tl, Mg, Tl ₂ Se, TlSe, Tl ₂ Se
₃ , Tl ₃ Te ₂ , TlTe, InBi, In ₂ Bi, Te
Bi, Tl-Se, Tl-Te, Pb-Sn, Bi-S
n, Se-Te, S-Se, Bi-Ga, Sn-Zn,
Ga-Sn, Ga-In, In 3 SeTe 2, AgInT
e ₂ , GeSb ₄ Te ₇ , Ge ₂ Sb ₂ Te ₅ , GeSb ₂ T
e ₄ , GeBi ₄ Te ₇ , GeBi ₂ Te ₄ , Ge ₃ Bi ₂ T
e ₆ , Sn ₂ Sb ₆ Se ₁₁ , Sn ₂ Sb ₂ Se ₅ , SnSb ₂
Te ₄ , Pb ₂ Sb ₆ Te ₁₁ , CuAsSe ₂ , Cu ₃ As
Se ₃ , CuSbS ₂ , CuSbSe ₂ , InSe, Sb ₂
Se ₃ , Sb ₂ Te ₃ , Bi ₂ Te ₃ , SnSb, FeT
e, Fe ₂ Te ₃ , FeTe ₂ , ZnSb, Zn ₃ Sb ₂ ,
VTe ₂ , V ₅ Te ₈ , AgIn ₂ , BiSe, InSb,
_{In 2 Te, In 2 Te 5} , and the like. It may be a mixed composition of these compounds or a compound of three or more elements close to the mixed composition.

The remaining components are GeSb ₄ Te ₇ and GeSb.
_It is preferably ₂ Te ₄ or Ge ₂ Sb ₂ Te ₅ .
In this case, GeSb ₂ Te ₄ is more preferable than GeSb ₄ Te _{7, and} Ge ₂ Sb ₂ Te ₅ is more preferable than GeSb ₂ Te ₄ . This is because the number of times of irradiation with the initialization laser beam for reducing the erase ratio to 25 dB is small. On the other hand, the range of the film thickness of the protective layer is GeSb ₄ Te ₇ , GeSb ₂ Te ₄ , Ge for making the structure in which the flow of the recording film is hard to occur.
_It becomes wider in the order of ₂ Sb ₂ Te ₅ .

GeSb ₄ Te ₇ , GeSb ₂ Te ₄ , or Ge ₂ Sb ₂ Te ₅ may have a composition close to that of GeSb ₄ Te ₇ , GeSb ₂ Te ₄ , or Ge ₂ Sb ₂ Te ₅ , or a mixed composition thereof or a compound of three or more elements close to the mixed composition.

(19) The first method for manufacturing an information recording thin film according to the present invention is the method for manufacturing an information recording thin film according to any one of the first to fifth aspects of the present invention, which is directly on the substrate or via a protective layer. Forming a raw material thin film by irradiating the raw material thin film with an energy beam to generate or grow a high-melting point component in the raw material thin film to obtain the information recording thin film. To do.

In the step of producing or growing the high melting point component in the raw material thin film, it is preferable to change the content of the high melting point component in the film thickness direction.

(20) A second method for producing an information recording thin film of the present invention is the fourth to fifth method for producing an information recording thin film of the present invention, which is directly on the substrate or via a protective layer. A step of forming an island-shaped seed crystal by depositing a material of the high melting point component or a material having a composition close to the composition of the high melting point component, and the high melting point component and the residual component on the seed crystal. A step of depositing a material containing, and selectively growing the high melting point component on the seed crystal, and growing the residual component so as to fill the space between the seed crystals. To do.

In the step of selectively growing the high melting point component, the content of the high melting point component is preferably changed in the film thickness direction.

(21) The first information recording medium of the present invention is characterized by comprising any one of the first to fifth information recording thin films as a recording layer.

(22) The second information recording medium of the present invention is characterized by including any one of the fourth to fifth information recording thin films as a mask layer for super-resolution reading.

(23) In the third information recording medium,
Any one of the fourth to fifth information recording thin films is provided as a reflective layer for super-resolution reading.

The reflective layer preferably has at least one of Si-Sn, Si-Ge and Si-In compounds, or a composition close to this. This is because the effect that the absorptance of the recording film can be controlled can be obtained.

(24) A fourth information recording medium of the present invention comprises any one of the first to fifth information recording thin films as a recording layer, and any one of the fourth to fifth information recording thin films. Is provided as a mask layer for super-resolution reading.

(25) A fifth information recording medium of the present invention comprises any one of the first to fifth information recording thin films as a recording layer, and any one of the fourth to fifth information recording thin films. Is provided as a reflective layer for super-resolution reading.

(26) In the first to fifth information recording media, the melting point of the residual component after the precipitation of the high melting point component is 6
It is preferably 50 ° C or lower. This is because there is a sufficient difference from the melting point of the high melting point component.

The reflectance of the reflective layer is preferably 60% or more. This is because the recording sensitivity increases.

The thickness of the reflective layer is 150 nm or more, 3
It is preferably 00 nm or less. If it is less than 150 nm, the C / N at the time of rewriting many times becomes a little lower,
This is because if the thickness exceeds 0 nm, it takes time to manufacture the film.

Further, a first protective layer made of SiO ₂ arranged on the side opposite to the recording film and a _second protective layer made of a ZnS-SiO ₂ layer arranged on the recording film side are further provided. Preferably, it is provided. This is because in this case, there is an effect of suppressing the flow of the recording film.

(27) A method of using the information recording medium of the present invention is a method of using the information recording medium having any one of the first to fifth information recording thin films as a recording layer.
The method is characterized by including a step of repeatedly irradiating the information recording medium with a laser beam during use to precipitate the high melting point component in the information recording thin film of the information recording medium.

Irradiation of the laser beam onto the information recording medium is preferably performed in an information recording / reproducing apparatus or an initialization apparatus for the information recording medium. This is because the recording film can be initialized quickly.

(28) In the first to fifth information recording thin films, when the information recording thin film is irradiated with laser light,
A high-melting point component having a melting point relatively higher than that of the remaining component of the information recording thin film is deposited, and the deposit contains the element X and is distributed in a region of the remaining component of the information recording thin film. You may

[0101]

According to the first to third information recording thin films of the present invention,
Since the element X is added to Ge, Sb, and Te, a high-melting-point component precipitate that is not melted by irradiation with a recording / reproducing energy beam such as a laser beam is generated inside. Therefore, even if the residual component other than the high melting point component is melted by the energy beam, its flow and segregation are effectively prevented as compared with the case where the high melting point component is not contained.

[0102] As a result, (the number of times exceeds example 10 ⁵ times) many times even when rewriting, carrier-to-noise ratio (C /
N) is stable, and rewriting or reading can be performed many times more than before while maintaining good recording and reproducing characteristics.

In the fourth to fifth information recording thin films of the present invention, the high melting point component precipitates are contained therein, so that the high melting point component precipitates are not melted by irradiation.
When an energy beam for recording / reproduction such as laser light is irradiated, even if the residual components other than the high melting point component are melted by the energy beam, its flow and segregation are more effective than when the high melting point component is not included. Be prevented.

As a result, the carrier-to-noise ratio (C / C / C / E) is rewritten many times (for example, more than 10 ⁵ times).
N) is stable, and rewriting or reading can be performed many times more than before while maintaining good recording and reproducing characteristics.

In the first and second information recording thin film manufacturing methods of the present invention, the first to ninth information recording thin films can be easily obtained.

In the first and fourth information recording media of the present invention, since any one of the first to fifth information recording thin films is provided as a recording layer, a large number of times (for example, a number of times exceeding 10 ⁵ times) ) Even when rewritten, the carrier-to-noise ratio (C
/ N) is stable, and rewriting or reading can be performed more times than before while maintaining good recording and reproducing characteristics.

In the second information recording medium of the present invention, since any one of the first to fifth information recording thin films is provided as a mask layer for super-resolution reading, a light spot is formed on the information recording medium. Is irradiated, at least a residual component other than the high melting point component is melted at a high temperature portion in the light spot.
The real part or imaginary part (extinction coefficient) of the refractive index at high temperature is
Since it becomes smaller than that of the low temperature part outside the light spot, the mask layer partially masks a part of the region of the light spot diameter, as if the light spot diameter decreased.

As a result, a recording mark smaller than the light spot diameter can be read, that is, super-resolution reading can be performed.

In the third and fifth information recording media of the present invention, any one of the first to fifth information recording thin films is provided as a reflective layer for super-resolution reading, and therefore the information recording medium. When the light spot is irradiated onto the light spot, at least the remaining components other than the high melting point component are melted in the high temperature portion in the light spot. When a light spot is applied to the reflective layer made of any one of the first to fifth information recording thin films, the real part of the refractive index or the extinction coefficient of the high temperature portion within the diameter of the light spot is outside the light spot. It becomes smaller than that of the low temperature part. For this reason,
The reflected light of the light irradiated to the high temperature portion of the reflective layer cannot have sufficient contrast for reading the recording mark.

As a result, since the light spot diameter is reduced, the recording marks formed with a pitch smaller than the light spot diameter can be read out, that is, super-resolution reading can be performed.

According to the first to third information recording medium manufacturing methods of the present invention, the first to third information recording media can be easily obtained.

In the method of using the information recording medium of the present invention,
Since the first to ninth information recording thin films of the present invention are irradiated with laser light at the time of use, precipitates of a high melting point component which are not melted by the irradiation of laser light are formed inside. Therefore, the advantages of the first to ninth information recording thin films of the present invention can be effectively utilized.

[0113]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 (Structure / Manufacturing Method) FIG. 3 shows a sectional structure of a disk-shaped information recording medium using the information recording thin film of Example 1 of the present invention. This medium was manufactured as follows.

First, with a diameter of 13 cm and a thickness of 1.2 mm,
A polycarbonate substrate 1 having a U-shaped tracking groove on its surface was formed. Next, the substrate 1 was placed in a magnetron sputtering apparatus in order to sequentially form the following thin films on the substrate 1. This device has a plurality of targets and is capable of sequentially forming a laminated film. Moreover, the uniformity and reproducibility of the formed film thickness are excellent.

First, (ZnS) 80%. (SiO ₂ ) was formed on the substrate 1 by using a magnetron sputtering device.
A thin film having a composition of 20%, that is, Zn ₄₀ S ₄₀ Si ₇ O
_The protective layer 2 consisting of ₁₃ films was formed to have a film thickness of about 130 nm. Then, C, which is a high melting point component, is formed on the protective layer 2.
After forming an r ₄ Te ₅ film (not shown) in an island shape to an average film thickness of 3 nm, Ge ₇ Sb ₂₇ Te ₅₇ Cr ₉ or (GeSb ₄ Te ₇ ) ₈ (Cr ₄ Te ₅ ) ₂ is formed thereon. The recording film 3 having the composition of was formed to a film thickness of about 22 nm. At this time, Cr ₄
A rotating co-sputtering method using a Te ₅ target and a GeSb ₄ Te ₇ target was used.

It is desirable that the size of each Cr ₄ Te ₅ film formed in an island shape is about 2 to 20 nm, and the island pitch is (island size) × 1.5 to 10 times. This is because, within this range, the number of laser irradiations for initialization can be reduced and noise does not increase.

In this step, the Cr ₄ Te ₅ film is not necessarily formed, but it is preferable to form it. that is,
This is because when the Cr ₄ Te ₅ film is not formed, the recording film 3 is likely to flow.

When the Cr ₄ Te ₅ film is not formed, the recording film 3
The high-melting-point components that precipitate inside are only those that occur during the initial crystallization described below.

Next, on the recording film 3, (ZnS) ₈₀ (Si
After forming the intermediate layer 4 of O ₂ ) ₂₀ film to a film thickness of about 40 nm, Al _{97 is} formed on the intermediate layer 4 in the same sputtering apparatus.
The reflection layer 5 made of a Ti ₃ film was formed to a film thickness of 200 nm. Thus, the first disc member was obtained.

On the other hand, a second disk member having the same structure as the first disk member was obtained by the completely same method. The second disc member has a diameter of 13 cm and a thickness of 1.2.
The film thickness is about 130 nm, which is sequentially stacked on the substrate 1'of mm.
Of the (ZnS) ₈₀ (SiO ₂ ) ₂₀ film,
Cr ₄ Te ₅ film (not shown) with an average film thickness of 3 nm, film thickness of about 2
2 nm of Ge ₇ Sb ₂₇ Te ₅₇ Cr ₉ , ie (GeSb
₄ Te ₇ ) ₈ (Cr ₄ Te ₅ ) ₂ recording film 3 ′, film thickness about ₄₀ n
The intermediate layer 4 ′ is made of a (ZnS) ₈₀ (SiO ₂ ) ₂₀ film of m, and the reflective layer 5 ′ is made of an Al ₉₇ Ti ₃ film having a thickness of 200 nm.

Thereafter, the reflective layers 5 and 5'of the first and second disk members are bonded to each other through the vinyl chloride-vinyl acetate hot melt adhesive layer 6 to record the disk-shaped information shown in FIG. The medium was obtained.

In this information recording medium, if the entire surfaces of the reflective layers 5 and 5'are adhered, the number of rewritable times can be increased as compared with the case where the entire surfaces are not adhered, and the reflective layers 5,
When the adhesive was not applied to the portion corresponding to the 5'recording area, the recording sensitivity was slightly higher than when the adhesive was also applied to that portion.

The composition of the recording films 3 and 3 of this information recording medium is expressed by the general formula: (Ge _0.08 Sb _0.33 Te _0.59 ) _0.91 C
It becomes r _0.09 . The additional element X is Cr.

(Initial Crystallization) The recording films 3, 3'of the disk-shaped information recording medium manufactured as described above were subjected to initial crystallization as follows. Since the same applies to the recording film 3 ', the recording film 3'will be described below.
Will be described only.

Disc-shaped information recording medium is set to 1800 rpm
The laser light power of the semiconductor laser (wavelength 830 nm) is maintained at a level (about 1 mW) where recording is not performed, and the laser light has a numerical aperture (NA) of 0. The light was condensed by the lens 55 and was irradiated onto the recording film 3 through the substrate 1. The reflected light from the recording film 3 is detected, and tracking is performed so that the center of the laser light spot always coincides with the center of the tracking groove of the substrate 1 or the middle of the adjacent tracking grooves. The recording head was driven while performing automatic focusing so that

First, for the initial crystallization, continuous (DC) laser light with a power of 15 mW was irradiated 200 times on the same recording track of the recording film 5. The irradiation time (light spot passage time) at each time is about 0.1 μsec.

Then, the continuous laser light of power 7 mW was changed to 5
Irradiated twice. Irradiation time of each time (light spot passage time)
Is also about 0.1 μsec. The laser light power at this time may be in the range of 5 to 9 mW.

Of the two types of laser light irradiation, the power
The irradiation of the lower one (7 mW) may be omitted, but the irradiation has better erasing characteristics.

As described above, irradiation with laser beams having different powers has an advantage that initialization can be sufficiently performed.

Irradiation of these laser beams is performed by a semiconductor laser.
Either by using an array, or by dividing the light beam from the gas laser into a plurality, or by making the spot shape of the light beam from the high power gas laser or semiconductor laser into an ellipse elongated in the radial direction of the medium. It is more preferable if it is used. This also makes it possible to reduce the number of rotations of the information recording medium until the initialization is completed.

When a plurality of laser light spots are used, if the laser light spots are not arranged on the same recording track but the positions are gradually shifted in the radial direction of the medium, a wide range can be obtained by one irradiation. Can be initialized,
It has the effect of reducing the remaining loss.

Next, a pulsed laser beam (for recording) having a power of 15 mW is emitted every time a continuous laser beam (high power beam for recording) having a circular spot power of 12 mW is irradiated once (irradiation time: about 0.1 μsec). Of high power light) to amorphize the recording film 5 to form recording points.

After that, in order to irradiate the recording point with a continuous laser beam having a power of 7 mW (low-power light for initialization) to crystallize (erasing the recording point), a continuous laser beam having a power of 7 mW is used. I investigated whether it was necessary to irradiate twice.

As a result, in the information recording medium of the first embodiment, the number of times the continuous laser beam with the power of 12 mW was applied from 1 to 100 times, the number of times the continuous laser beam with the power of 7 mW required for crystallization was applied. , It decreased as the irradiation frequency increased. That is, it was found that crystallization was more likely to occur as the number of irradiations increased. This is a high melting point component C in the recording film 5 due to the irradiation of continuous laser light with a power of 12 mW.
GeS capable of high-speed crystallization of the composition of the remaining portion (phase change portion) of the recording film 5 in which many fine crystals of r ₄ Te ₅ are deposited.
It is presumed that the composition was close to that of b ₄ Te ₇ .

The melting point of Cr ₄ Te ₅ is 1252 ° C.,
The melting point of GeSb ₄ Te ₇ is 605 ° C.

Further, the following test was conducted assuming a signal in the mark edge recording system.

For example, a signal A corresponding to repetition of a recording mark of length 2T and a space of length 8T while randomly shifting the signal writing start position on the recording track within a range of length 16T (1T is 45 ns). , A signal B corresponding to repetition of a recording mark having a length of 8T and a space having a length of 2T
When information is recorded on the recording film 5 by alternately repeating and, the formation frequency of the recording mark changes abruptly at the switching portion between the signal A and the signal B. Therefore, when the recording film 5 flows, the recording film material that has flowed is stopped and deposited, or the recording film material flows out without being introduced from the rear and the film thickness becomes thin. The waveform is distorted.

When the element in the recording film 5 is segregated, the element is similarly deposited or insufficient. as a result,
After all, the waveform of the reproduced signal is distorted.

Irradiation of continuous laser light is effective for preventing such a phenomenon. That is, when the flow or segregation occurs in the recording film 5, the reverse flow or segregation is likely to occur due to the resulting film thickness or concentration gradient, and as a result, further flow or segregation is suppressed. is there.
Therefore, before the information recording medium is used, if the continuous laser beam with a high power (15 mW) is repeatedly applied to a slightly wider area than the recording area, the above phenomenon in the recording area can be prevented to some extent.

Therefore, for each information recording medium, the magnitude of the distortion of the reproduced signal waveform due to the rewriting of the information consisting of the signal A and the signal B a number of times is used as an index, and the continuous laser light necessary for preventing the above phenomenon is generated. The number of irradiations was calculated.

The greater of the required number of times of laser light irradiation for increasing the crystallization rate and the required number of times of laser light irradiation for reducing the waveform distortion is necessary for the initialization of the information recording medium. It is the number of times of laser light irradiation.

In the information recording medium of the first embodiment, the number of times of irradiation for increasing the crystallization rate was larger than that for decreasing the waveform distortion, and the number of times was 100 times.

(Recording / Erasing) Next, in the recording area of the recording film 3 in which the initial crystallization is completed as described above, while performing tracking and automatic focusing in the same manner as described above,
According to the information to be recorded, the power of the recording laser light is set to an intermediate power level (7 mW) and a high power level (15 mW).
The information was recorded by changing between Reproduces (reads out) laser light power when passing through the area to be recorded
The power level of the laser light for use was lowered to a low power level (1 mW). The amorphous point or a portion close to it which is formed in the recording area by the recording laser beam becomes the recording point.

The power ratio between the high level and the intermediate level of the recording laser light is particularly preferably in the range of 1: 0.3 to 1: 0.8. This is because the recording / erasing characteristics are good in this range.

In addition to this, other power levels may be set for a short time.

In such a recording method, if new information is recorded directly on a portion where information has already been recorded, it can be rewritten with new information. That is, overwriting with a single circular light spot is possible.

However, the power (eg, 8 m) close to the intermediate power level (7 mW) of the power-modulated recording laser beam in the first one or more rotations during rewriting.
W) continuous light is applied to erase the recorded information, and then, in the next one rotation, a low power level (1 mW) of the reproducing (reading) laser light and a high power level of the recording laser light. During (15 mW) or between the intermediate power level (7 mW) and the high power level (15 mW) of the recording laser light, the power modulated laser light is irradiated according to the information to be recorded for recording. Good.
In this way, if the information is erased and then recorded, the previously written information remains less and the high carrier-to-noise ratio (C / N) is obtained.

In the case of rewriting after erasing in this way, the power level of the continuous laser beam to be initially irradiated is 0.4 to 1 when the high level (15 mW) of the recording laser beam is 1. It is preferable to set it in the range of 1. This is because good rewriting can be performed within this range.

In the information recording medium of Example 1, the power of the laser beam was increased by 15% from the optimum value under the severe condition,
It was possible to repeat recording / erasing 10 ⁵ times or more. In addition, the C of the reproduced signal when the 2 MHz signal is recorded
/ N was about 50 dB, which was extremely good.

In the recording film 3 of this embodiment, the number of rewritable times can be set to 10 ⁵ or more because the high melting point component deposited in the recording film 3 causes the residual component (phase change portion) of the recording film 3 to be rewritten. It is understood that the flow or segregation of) is prevented.

The ZnS- formed on the recording film 3
When the intermediate layer 4 of SiO ₂ and the reflective layer 5 of Al—Ti were omitted, a slight increase in noise occurred after recording and erasing by an order of magnitude less than the above. Therefore, the intermediate layer 4 and the reflective layer 5
However, it was confirmed that the number of rewritable times had a considerably large effect.

(Relationship with Ge composition ratio a: GeSb ₄ Te ₇
2) In the triangular phase diagram of FIG. 2, the Cr content connecting Ge ₆₅ Te ₂₅ Cr ₁₀ and Sb ₃₀ Te ₆₀ Cr ₁₀ is constant (10
(Atomic%), the composition was changed on a straight line, and the crystallization temperature of the unrecorded part when the temperature was raised at a constant rate and the number of times of laser light irradiation required for initialization were measured. As a result, the following data were obtained.

Composition Crystallization temperature Laser light irradiation frequency Sb ₃₀ Te ₆₀ Cr ₁₀ 120 ° C 200 times or less Ge ₂ Sb ₂₉ Te ₅₉ Cr ₁₀ 130 ° C 200 times or less Ge ₄ Sb ₂₈ Te ₅₈ Cr ₁₀ 150 ° C 200 times Ge ₁₀ Sb ₂₅ Te ₅₅ Cr ₁₀ 160 ° C 200 times or less Ge ₁₅ Sb ₂₃ Te ₅₂ Cr ₁₀ 170 ° C 500 times Ge ₁₇ Sb ₂₂ Te ₅₁ Cr ₁₀ 170 ° C 2000 times Ge ₂₅ Sb ₁₈ Te ₄₇ Cr ₁₀ 180 ° C 5000 times From these results, the Ge composition ratio a is 0.02 ≤ a ≤ 0.1.
It was found that in the range of 9, an appropriate crystallization temperature can be obtained and the number of times of laser light irradiation required for initialization can be reduced.

(Relationship with Sb composition ratio b: GeSb ₄ Te ₇
2) In the triangular phase diagram of FIG. 2, the Cr content that connects Sb ₄₅ Te ₄₅ Cr ₁₀ and Ge ₁₈ Te ₇₂ Cr ₁₀ is constant (10
(Atomic%), the composition was changed on a straight line, and the crystallization temperature of the unrecorded part when the temperature was raised at a constant rate and the number of times of laser light irradiation required for initialization were measured. As a result, the following data were obtained.

Composition Crystallization temperature Laser light irradiation frequency Ge ₁₇ Sb ₂ Te ₇₁ Cr ₁₀ 210 ° C 5000 times Ge ₁₇ Sb ₄ Te ₆₉ Cr ₁₀ 200 ° C 1000 times Ge ₁₄ Sb ₁₀ Te ₆₆ Cr ₁₀ 180 ° C 500 times Ge ₁₀ Sb ₂₀ Te ₆₀ Cr ₁₀ 170 ° C 200 times or less Ge ₇ Sb ₂₆ Te ₅₇ Cr ₁₀ 160 ° C 200 times or less Ge ₅ Sb ₃₃ Te ₅₂ Cr ₁₀ 150 ° C 200 times or less Ge ₃ Sb ₃₆ Te ₅₁ Cr ₁₀ 140 ° C 200 times or less Ge ₂ Sb ₄₀ Te ₄₈ Cr ₁₀ 120 ° C 200 times or less From these results, the composition ratio b of Sb is 0.04 ≦ b ≦ 0.4.
It was found that in the range of (3), an appropriate crystallization temperature can be obtained, and the number of times of laser light irradiation required for initialization can be reduced.

(Relationship with Te composition ratio c: GeSb ₄ Te ₇
2) In the triangular phase diagram of FIG. 2, the Cr content connecting Sb ₁₅ Te ₇₅ Cr ₁₀ and Ge ₃₀ Sb ₆₀ Cr ₁₀ is constant (10
%) And the composition was changed on a straight line, and the laser light irradiation time required for erasing recorded information and rewriting 10 ⁵ times under severe conditions where the laser light power was 15% higher than the optimum value The change in carrier-to-noise ratio (C / N) of the reproduced signal was measured. As a result, the following data were obtained.

Composition Laser light irradiation time C / N Ge ₁₄ Sb ₃₆ Te ₄₀ Cr ₁₀ 0.5 μsec ₄₄ dB Ge ₁₂ Sb ₃₃ Te ₄₅ Cr ₁₀ 0.2 μsec 48 dB Ge ₁₁ Sb ₃₁ Te ₄₈ Cr ₁₀ 0.1 μsec 50 dB _{Ge 8 Sb 27 Te 55 Cr 10} 0.1μsec 50dB Ge 5 Sb 22 Te 63 Cr 10 0.5μsec 50dB Ge 3 Sb 19. 5 Te 67. 5 Cr 10 1.0μsec 50dB Sb 15 Te 75 Cr 10 3.0μsec 50dB From this result, the composition ratio c of Te is 0.5 ≦ c ≦ 0.75.
It was found that the irradiation time of the laser beam required for erasing can be shortened and the carrier-to-noise ratio (C / N) of the reproduced signal after rewriting 10 ⁵ times can be improved in the range.

(Relationship with Cr composition ratio d: GeSb ₄ Te ₇
(Around) The composition ratio of Cr ₄ Te ₅ (while maintaining the ratio of a, b, and c that represents the composition ratio of Ge, Sb, and Te that is the balance of Cr ₄ Te ₅ to a: b: c = 1: 4: 7) ( The C / N of the reproduced signal after rewriting 10 ⁵ times under severe conditions in which the power of the laser beam was increased by 15% from the optimum value was measured by changing the content d). As a result, the following data were obtained regarding the Cr composition ratio d.

[0160] Further, when the composition ratio (content) d of Cr is changed, under initialization of 200 times under the severe condition that the power of the laser beam is higher than the optimum value by 15%, after recording the information once, When the other information was overwritten once, the "erase ratio" of the reproduced signal changed as follows.

[0161] Here, the "erase ratio" represents the C / N ratio of the reproduced signal before and after overwriting when another information of different frequency is overwritten on the already recorded information in dB. . From this result, it was found that the erasing ratio decreased as the Cr composition ratio d increased.

Therefore, the Cr composition ratio d is 0.03 ≦ d.
In the range of ≤0.3, the irradiation time of the laser beam required for erasing can be shortened, and the laser beam power is set to 1 from the optimum value.
It was found that the carrier-to-noise ratio (C / N) of the reproduced signal after rewriting 10 ⁵ times under the strict condition of 5% higher becomes better.

From the above, the Cr ₉ Ge ₇ Sb of Example 1 was prepared.
₂₇ Te ₅₇ , that is, (GeSb ₄ Te ₇ ) ₈ (Cr ₄ T
For the recording film 3 of e ₅ ) ₂ , the power of the laser light is set to 1 from the optimum value.
The C / N and erase ratio of the reproduced signal after rewriting 10 ⁵ times under a strict condition of 5% higher are 50 dB or more and 25 dB or more, respectively, and rewriting can be performed 2 × 10 ⁵ times or more, which is an extremely excellent recording.・ It was found to have a reproduction characteristic.

(Other Example 1 of Additional Element X) In the above description, Cr is used as the additional element X, but instead of part or all of Cr, Ag, Cu,
Ba, Co, La, Ni, Pt, Si, Au, Cd, L
i, Mo, Mn, Al, Fe, Pb, Na, Cs, G
Even if at least one of a, Pd, Bi, Sn, Ti, V, In and Sr, and the lanthanoid element is added, almost the same characteristics as the above case can be obtained.

For example, when Cu was added in place of all Cr (composition ratio of Cu: q), the following data was obtained.

Reproduction signal after rewriting 10 ⁵ times C / N q = 0 42 dB q = 0.03 47 dB q = 0.1 49 dB q = 0.2 50 dB q = 0.3 48 dB From this result, Cu was added. In this case, it was confirmed that the same result as Cr was obtained.

(Other Example 2 of Additive Element X) In addition to Cr,
It is preferable to add Tl (thallium). Tl has the effect of speeding up erasing and increasing C / N, so Cr
C / N becomes larger than when only added,
There is also an advantage that the number of rewritable times increases.

However, it is preferable that the sum of the addition amounts of Cr and Tl is 3 atom% or more and 30 atom% or less, because the remaining unerased is not large.

For example, Ge ₇ Sb ₂₇ Te ₅₇ Cr _8.5 Tl
_{With a 0.5} recording film, a C / N of 50 dB and a rewritable number of 2 × 10 ⁵ times were obtained.

Similar characteristics can be obtained by adding at least one halogen element instead of part or all of Tl.

When N (nitrogen) is added instead of Tl,
The number of rewritable times is further improved. However, if the amount is too large, the reproduction signal level is lowered, so the addition amount is preferably 1 atom% or more and 10 atom% or less.

(Other Example 3 of Additional Element X) Se may be added in place of Tl (thallium). When Se is added in an amount of 1 atom% or more and 20 atom% or less while keeping the relative ratio of other elements constant, the effect of improving the oxidation resistance or optimizing the reflectance can be obtained.

(Another Example of Phase Change Component) A part of GeSb ₄ Te ₇ , which is the phase change component of Example 1, is replaced with GeSb ₂ Te.
_When replaced with at least one of ₄ and Ge ₂ Sb ₂ Te ₅ , the number of laser irradiations required for initialization tends to increase as the Ge content increases, but other properties are You get something close.

(Other Examples of High Melting Point Component) The high melting point component to be precipitated may be a compound, a simple element or an alloy. Therefore, a part of Cr ₄ Te ₅ , which is the high-melting point component of Example 1, is partially converted into, for example, LaTe ₂ , La ₂ Te ₃ , La ₃ Te ₄ , and L ₄ .
aTe, La ₂ Te ₅ , La ₄ Te ₇ , LaTe ₃ , La ₃ T
e, La ₂ Sb, La ₃ Sb ₂ , LaSb, LaSb ₂ , L
_{a 3 Ge, La 5 Ge 3} , La 4 Ge 3, La 5 Ge 4, La
Ge, La ₃ Ge ₅ , Ag ₂ Te, Cr ₅ Te ₈ , Cr ₂ Te
₃ , CrSb, Cr ₃ Ge, Cr ₅ Ge ₃ , Cr ₁₁ Ge ₈ ,
CrGe, Cr ₁₁ Ge ₁₉ , PtTe ₂ , Pt ₄ Te ₅ , P
t ₅ Te ₄ , Pt ₄ Sb, Pt ₃ Sb ₂ , PtSb, Pt ₃ G
e, Pt ₂ Ge, Pt ₃ Ge ₂ , PtGe, Pt ₂ Ge ₃ ,
PtGe ₃ , NiTe, NiTe ₀ . ₈₅ , NiSb, Ni
₃ Ge, Ni ₅ Ge ₂ , Ni ₅ Ge ₃ , NiGe, CoT
e ₂ , CoSb ₂ , CoSb ₃ , Co ₅ Ge ₂ , Co ₅ G
e ₃ , CoGe, Co ₅ Ge ₇ , CoGe ₂ , Si ₂ Te ₃ ,
_{SiSb, SiGe, CeTe, Ce 3} Te 4, Ce 2 T
e ₃ , Ce ₄ Te ₇ , CeTe ₂ , CeTe ₃ , Ce ₂ Sb,
Ce ₅ Sb ₃ , Ce ₄ Sb ₅ , CeSb, CeSb ₂ , Ce ₃
Ge, Ce ₅ Ge ₃ , Ce ₄ Ge ₃ , Ce ₅ Ge ₄ , CeG
e, Ce ₃ Ge ₅ , Ce ₅ Si ₃ , Ce ₃ Si ₂ , Ce ₅ S
i ₄ , CeSi, Ce ₃ Si ₅ , CeSi ₂ , Cr ₃ Si,
Cr ₅ Si ₃ , CrSi, CrSi ₃ , CrSi ₂ , Co ₃
Si, CoSi, CoSi ₂ , NiSi ₂ , NiSi, N
i ₃ Si ₂ , Ni ₂ Si, Ni ₅ Si ₂ , Ni ₃ Si, Pt ₅
Si ₂ , Pt ₂ Si, PtSi, LaSi ₂ , Ag ₃ In,
Ag ₂ In, Bi ₂ Ce, BiCe, Bi ₃ Ce ₄ , Bi ₃
Ce ₅ , BiCe ₂ , Cd ₁₁ Ce, Cd ₆ Ce, Cd ₅₈ C
e ₁₃ , Cd ₃ Ce, Cd ₂ Ce, CdCe, Ce ₃ In,
Ce ₂ In, Ce ₁ + xIn, Ce ₃ In ₅ , CeIn ₂ ,
CeIn ₃ , Ce ₂ Pb, CePb, CePb ₃ , Ce ₃ S
_{n, Ce 5 Sn 3, Ce} 5 Sn 4, Ce 11 Sn 10, Ce 3 S
n ₅ , Ce ₃ Sn ₇ , Ce ₂ Sn ₅ , CeSn ₃ , CeZn,
CeZn ₂ , CeZn ₃ , Ce ₃ Zn ₁₁ , Ce ₁₃ Zn ₅₈ ,
CeZn ₅ , Ce ₃ Zn ₂₂ , Ce ₂ Zn ₁₇ , CeZn ₁₁ ,
Cd ₂₁ Co ₅ , CoGa, CoGa ₃ , CoSn, Cr ₃
Ga, CrGa, Cr ₅ Ga ₆ , CrGa ₄ , Cu ₉ G
a ₄ , Cu ₃ Sn, Cu ₃ Zn, Bi ₂ La, BiLa, B
i ₃ La ₄ , Bi ₃ La ₅ , BiLa ₂ , Cd ₁₁ La, Cd
₁₇ La ₂ , Cd ₉ La ₂ , Cd ₂ La, CdLa, Ga ₆ L
a, Ga ₂ La, GaLa, Ga ₃ La ₅ , GaLa ₃ , I
n ₃ La, In ₂ La, In ₅ La ₃ , In _x La, InL
a, InLa ₂ , InLa ₃ , La ₅ Pb ₃ , La ₄ Pb ₃ ,
La ₁₁ Pb ₁₀ , La ₃ Pb ₄ , La ₅ Pb ₄ , LaPb ₂ ,
LaPb ₃ , LaZn, LaZn ₂ , LaZn ₄ , LaZ
_{n 5, La 3 Zn 22,} La 2 Zn 17, LaZn 11, LaZ
n ₁₃ , NiBi, Ga ₃ Ni ₂ , GaNi, Ga ₂ Ni ₃ ,
Ga ₃ Ni ₅ , GaNi ₃ , Ni ₃ Sn, Ni ₃ Sn ₂ , Ni
₃ Sn ₄ , NiZn, Ni ₅ Zn ₂₁ , PtBi, PtB
i ₂ , PtBi ₃ , PtCd ₂ , Pt ₂ Cd ₉ , Ga ₇ P
t ₃ , Ga ₂ Pt, Ga ₃ Pt ₂ , GaPt, Ga ₃ Pt ₅ ,
GaPt ₂ , GaPt ₃ , In ₇ Pt ₃ , In ₂ Pt, In ₃
Pt ₂ , InPt, In ₅ Pt ₆ , In ₂ Pt ₃ , InP
t ₂ , InPt ₃ , Pt ₃ Pb, PtPb, Pt ₂ Pb ₃ ,
Pt ₃ Sn, PtSn, Pt ₂ Sn ₃ , PtSn ₂ , PtS
n ₄ , Pt ₃ Zn, PtZn ₂ , AlS, Al ₂ S ₃ , Ba
S, BaC ₂ , CdS, Co ₄ S ₃ , Co ₉ S ₈ , CoS,
CoO, Co ₂ O ₄ , Co ₂ O ₃ , Cr ₂ O ₃ , Cr ₃ O ₄ , C
rO, CrS, CrN, Cr ₂ N, Cr ₂₃ C ₆₃ , Cr ₇ C
₃ , Cr ₃ C ₂ , Cu ₂ S, Cu ₉ S ₅ , CuO, Cu ₂ O,
In ₄ S ₅ , In ₃ S ₄ , La ₂ S ₃ , La ₂ O ₃ , Mo ₂ C,
MoC, Mn ₂₃ C ₆ , Mn ₄ C, Mn ₇ C ₃ , NiO, Si
_{S 2, SiO 2, Si 3} N 4, Cu 2 Te, CuTe, Cu 3
Sb, Mn ₂ Sb, MnTe, MnTe ₂ , Mn ₅ Ge ₃ ,
Mn ₃ . ₂₅ Ge, Mn ₅ Ge, Mn ₃ Ge ₂ , Ge ₃ W, T
e ₂ W, AlSb, Al ₂ Te ₃ , Fe ₂ Ge, FeG
e ₂ , FeSb ₂ , Mo ₃ Sb ₇ , Mo ₃ Te ₄ , MoT
e ₂ , PbTe, GePd ₂ , Ge ₂ Pd ₅ , Ge ₉ P
d ₂₅ , GePd ₅ , Pd ₃ Sb, Pd ₅ Sb ₃ , PdSb,
_{SnTe, Ti 5 Ge 3, Ge} 31 V 17, Ge 8 V 11, Ge 3
V ₅ , GeV ₃ , V ₅ Te ₄ , V ₃ Te ₄ , ZnTe, Ag ₂
Se, Cu ₂ Se, Al ₂ Se ₃ , InAs, CoSe,
Mn ₃ In, Ni ₃ In, NiIn, Ni ₂ In ₃ , Ni ₃
A high melting point compound containing the element X such as In ₇ , PbSe, or a high melting point oxide of the constituent elements of the above high melting point component, or a composition close to it, or a mixed composition or mixed composition thereof. Similar results can be obtained by substituting at least one of the close ternary or higher compounds.

Of these, Cr ₄ Te ₅ , CrSb,
LaSb, CoSb, Cr ₃ Te ₄ , LaTe ₃ , Cr ₂ T
e ₃ , Cr ₃ Te ₄ , CoTe, Co ₃ Te ₄ , Cu ₂ Te,
CuTe, Cu ₃ Sb, MnTe, MnTe ₂ , Mn ₂ S
At least one of b is particularly preferred. This is because in the initial crystallization, the recording / erasing characteristics are stabilized by irradiating the laser beam a smaller number of times. However, elemental elements and alloys are likely to be compounds, and it is difficult to reduce the difference in complex refractive index between the high melting point component and the phase change component. Therefore, the compound is the most preferable, followed by the alloy and the simple substance.

(Amount of High Melting Point Component Content) The content of oxides, sulfides, nitrides, and carbides contained in the high melting point component precipitates is preferably less than 40 atom% of the high melting point component. It is particularly preferable that the amount is less than 10 atomic%. If the content of these elements exceeds 40 atomic%, the difference in the complex refractive index from the phase change component cannot be reduced, or oxygen or the like diffuses into the phase change component to deteriorate the recording / reading characteristics. This is because it easily occurs. If less than 10 atom%,
Such problems are extremely unlikely to occur.

In the above-mentioned numerous compounds described as examples of the high melting point component, the interface reflectance of the recording film 3 changed as follows when the content v ′ of the transition metal element was different.

[0178] From this result, it is found that the interface reflectance increases as the content v ′ of the transition metal element increases. Therefore, in order to increase the interface reflectance of the recording film 3, it is preferable to increase the content v ′ of the transition metal element.

(Content of High Melting Point Compound in Recording Film) The content x of the high melting point compound contained in the recording film 3 is defined as the total composition of the high melting point component which is the sum of the number of atoms of the constituent elements of the high melting point compound. Expressed as a ratio (atomic%) to the sum of the number of atoms of the element, and when the content x was changed, the number of rewritable times changed as follows.

[0180] In addition, under the severe condition that the laser light power is increased by 15%, 1
The erase ratio after rewriting 0 ⁵ times changed as follows.

Erase ratio after rewriting 10 ⁵ times x = 30 atom% 30 dB x = 40 atom% 30 dB x = '= 35% 2% v' = 50% 6% From this result, the content v'of the transition metal element is shown. It can be seen that the interfacial reflectance increases as is increased. Therefore, in order to increase the interface reflectance of the recording film 3, it is preferable to increase the content v ′ of the transition metal element.

(Content of High Melting Point Compound in Recording Film) The content x of the high melting point compound contained in the recording film 3 is defined as the total composition of the high melting point component which is the sum of the number of atoms of the constituent elements of the high melting point compound. Expressed as a ratio (atomic%) to the sum of the number of atoms of the element, and when the content x was changed, the number of rewritable times changed as follows.

[0183] In addition, under the severe condition that the laser light power is increased by 15%, 1
The erase ratio after rewriting 0 ⁵ times changed as follows.

Erasure ratio after rewriting 10 ⁵ times x = 30 atomic% 30 dB x = 40 atomic% 30 dB x = 50 atomic% 25 dB x = 60 atomic% 23 dB As a result, inclusion of the high melting point compound contained in the high melting point component As the quantity x increases, the number of rewritable times increases,
It can be seen that if it increases too much, the erase ratio after rewriting 10 ⁵ times decreases. Therefore, the content x of the high melting point compound is
It has been found that the range of 10 atomic% ≤ x ≤ 50 atomic% is preferable.

(Content ratio 1 of low-melting point component and high-melting point component in recording film) The average composition of the recording film 3 is set to the low melting point component L (GeSb ₄ Te ₇ ) of elemental element or compound composition and elemental element or compound. The high melting point component H (Cr ₄ Te ₅ ) of the composition is represented by the formula of L _j H _k , and when the content k of the high melting point component H of Cr ₄ Te ₅ is changed, the laser power is increased by 15% The jitter after rewriting 10 ⁵ times under the conditions changed as follows.

Composition Jitter (GeSb ₄ Te ₇ ) ₉₀ (Cr ₄ Te ₅ ) ₁₀ 4 ns (GeSb ₄ Te ₇ ) ₈₀ (Cr ₄ Te ₅ ) ₂₀ 2 ns (GeSb ₄ Te ₇ ) ₇₀ after rewriting 10 ⁵ times (Cr ₄ Te ₅ ) ₃₀ 2 ns (GeSb ₄ Te ₇ ) ₆₀ (Cr ₄ Te ₅ ) ₄₀ 3 ns (GeSb ₄ Te ₇ ) ₅₀ (Cr ₄ Te ₅ ) ₅₀ 5 ns From these results, the above j and k are 0.2. ≤ [k / (j +
k)] ≦ 0.4, preferably 0.2
It has been found that it is more preferable to satisfy the relational expression ≦ [k / (j + k)] ≦ 0.3.

In this case, the recording film 3 has Ge, Sb, T as the reference composition for j and k, and the composition satisfying the relational expression as a reference composition.
The content of each element of e and Cr is preferably within the range of ± 10 atom% with respect to the standard composition, and ± 5 atom%
It has also been found that it is more preferable to be within the range.

(Content ratio of low-melting point component and high-melting point component in recording film 2) The average composition of the recording film 3 is set to the low-melting point component L (GeSb ₂ Te ₄ ) of elemental element or compound composition and elemental element or compound. Due to the high melting point component H (Cr ₄ Te ₅ ) of the composition
Cr ₄ Te ₅ which is a high melting point component H and is represented by the formula of L _j H _k.
When the content k of was changed, the jitter (fluctuation) of the reproduced signal waveform after rewriting 10 ⁵ times under severe conditions with the laser power increased by 15% changed as follows.

Composition Jitter (GeSb ₂ Te ₄ ) ₉₆ (Cr ₄ Te ₅ ) ₄ 4 ns (GeSb ₂ Te ₄ ) ₈₈ (Cr ₄ Te ₅ ) ₁₂ 2 ns (GeSb ₂ Te ₄ ) ₇₈ after Rewriting 10 ⁵ Times (Cr ₄ Te ₅ ) ₂₂ 2 ns (GeSb ₂ Te ₄ ) ₆₅ (Cr ₄ Te ₅ ) ₃₅ 3 ns From these results, it can be seen that the low melting point component L is GeSb ₂ Te ₄ and the high melting point component H is Cr ₄ Te _5. Is j, k is 0.
It has been found that it is preferable to satisfy the relational expression 12 ≦ [k / (j + k)] ≦ 0.22.

In this case, the recording film 3 has Ge, Sb, Te as a reference composition whose composition is such that j and k satisfy the relational expression.
The content of Cr and Cr elements is ± with respect to the standard composition.
It has also been found that it is preferably in the range of 10 atom%, and more preferably in the range of ± 5 atom%.

(Content ratio 3 of low melting point component and high melting point component in recording film) The low melting point component L of the recording film 3 is Ge ₂ Sb ₂ T.
e ₅ , when the high melting point component H is Cr ₄ Te ₅ ,
The following test was conducted by changing the content k of Cr ₄ Te ₅ which is the high melting point component H.

The number of irradiations of the initialization laser light was determined so that an erasing ratio of 25 dB or more can be obtained when recording / erasing is performed after initialization by laser light irradiation. Further, the jitter after rewriting 10 ⁵ times was examined under the severe condition that the laser light power was increased by 15%. As a result, the following data were obtained.

[0193] 10 ⁵ times of rewriting the set formed jitter after _{(Ge 2 Sb 2 Te 5)} 100 (Cr 4 Te 5) 0 7ns (Ge 2 Sb 2 Te 5) 99 (Cr 4 Te 5) 1 4ns (Ge 2 _{Sb 2 Te 5) 95 (Cr} 4 Te 5) 5 2ns (Ge 2 Sb 2 Te 5) 90 (Cr 4 Te 5) 10 2ns (Ge 2 Sb 2 Te 5) 85 (Cr 4 Te 5) 15 2ns (Ge ₂ Sb ₂ Te ₅ ) ₇₅ (Cr ₄ Te ₅ ) ₂₅ 3 ns From these results, when the low melting point component L is Ge ₂ Sb ₂ Te ₅ and the high melting point component H is Cr ₄ Te ₅ , the above j, k Is
It has been found that it is preferable to satisfy the relational expression of 0.05 ≦ [k / (j + k)] ≦ 0.15.

In this case, the recording film 3 has 0.05 ≦
The composition satisfying the relational expression [k / (j + k)] ≦ 0.15 is used as a reference composition, and the content of Cr is within ± 3 atomic% with respect to the reference composition, and Ge, Sb, and Te are It was also found that the content is preferably within the range of ± 10 atom% with respect to the above-mentioned standard composition, and more preferably within the range of ± 5 atom%.

From the above content ratios 1 to 3 of the low melting point component L and the high melting point component H in the recording film, the content g (atomic%) of Ge in the low melting point component and k and j are [k It has been found that it is preferable to satisfy the relational expression of /(j+k)]=[2/g]+0.01.

With respect to the standard composition represented by the above relational expression,
When the content of each element was within the range of ± 10 atom%, the deterioration of the recording / erasing characteristics could be prevented, and within the range of ± 5 atom%, the decrease could be further prevented.

The low melting point component L is L = (L ₁ ) _p (L
₂ ) It may be composed of a plurality of components as represented by _q (L ₃ ) _r . For example, Ge ₂ Sb ₂ Te ₅ has L =
As (GeTe) ₂ (Sb ₂ Te ₃ ) ₁ represents (GeT
e) and (Sb ₂ Te ₃ ) components.

Similarly, the high-melting-point component H also has H = (H ₁ ) _s (H
₂ ) _t (H ₃ ) _u ..., And may be composed of a plurality of components. For example, Cr ₄ Te ₅ is H = (Cr) ₁ (Cr ₃ Te
₄ ) It is considered that it is composed of (Cr) and (Cr ₃ Te ₄ ) components as represented by ₅ .

(Complex refractive index of high melting point component) The real part n ₁ and the imaginary part (extinction coefficient) k ₁ of the complex refractive index of the high melting point component of the recording film 3 are the phase change component (remaining component) of the recording film 3. ), The difference between the crystallized states n ₂ and k ₂ , Δn = (| n ₁ −n ₂ | / n ₁ ) × 100, Δk = (| k ₁ −k ₂ | / k ₁ ) × 100 , The C / N of the reproduced signal changed as follows after rewriting 10 ⁵ times under severe conditions in which the power of the laser beam was made 15% higher than the optimum value. This change in C / N is mainly due to the change in N level.

C / N Δk, Δn = 10% 49 dB Δk, Δn = 20% 48 dB Δk, Δn = 30% 47 dB Δk, Δn = 40% 46 dB Δk, Δn = 50% 43 dB of the reproduced signal after rewriting 10 ⁵ times From this result, it was found that it is preferable that the differences Δn and Δk between the real number part and the imaginary number part (extinction coefficient) of the complex refractive index of the high melting point component are both small.

(Structure / Dimension of Precipitate of High Melting Point Component) FIG. 1
FIG. 4 is a partially enlarged cross-sectional view showing details of a Z part in FIG. 3. The high-melting point component such as Cr ₄ Te ₅ described above is shown in FIG.
(B) It deposits inside the recording film 3 in the form as shown in (c).

In FIG. 1A, a large number of "granular" precipitates of the high melting point component 3b are distributed in the recording film 3 in an independent state. The portion other than the high melting point component 3b of the recording film 3, that is, the remaining component is the phase change component 3a. The length of the high melting point component 3b in the film surface direction and the length in the direction perpendicular to the film surface are substantially the same, or even if they are different, the difference in length is small. Here, some of the precipitates of the high melting point component 3b are in contact with one of the interfaces of the recording film 3, and some of them are not in contact with any of the interfaces.

In the medium of FIG. 3, the high melting point component 3b is Cr ₄
Te ₅ and the phase change component 3a are made of GeSb ₄ Te ₇ .

In FIG. 1B, a large number of precipitates of the high melting point component 3b are independently distributed in the recording film 3 as in the case of FIG. 1A. However, the difference is that the high melting point component 3b is deposited in a "columnar" shape. That is, the length of the high melting point component 3b in the direction perpendicular to the film surface is larger than the length in the film surface direction, and the cross section perpendicular to the film surface is columnar. Some of the deposits of the high melting point component 3b are in contact with one interface of the recording film 3, and others are in contact with the other interface of the recording film 3. here,
Nothing touches both interfaces.

In FIG. 1C, a large number of precipitates of the high melting point component 3b are connected to each other and distributed in the recording film 3 in an integrated state. That is, the high-melting-point component 3b is deposited in a "porous" state, and the phase-change component 3a is embedded in many small holes of the high-melting-point component 3b.
The porous high melting point component 3b is in contact with both interfaces of the recording film 3. The phase change components 3a are distributed in the recording film 3 independently of each other. This state corresponds to the case in which the phase change component 3a and the high melting point component 3b are replaced in the case of FIG. 1 (a).

One of the states (a) to (c) of FIG. 1 appears depending on the film forming conditions of the recording film 3 and the initial crystallization conditions. In either state, the high melting point component 3b Due to
The phase change component 3a is prevented from flowing and segregating when the recording film 3 is heated and melted, and as a result, the number of rewritable times is improved.

In the present invention, the "maximum external dimension y", "height h and h '" of the precipitate of the high melting point component 3b,
The “center-to-center distance i”, the “maximum hole size p ′”, and the “maximum wall thickness w” are defined as follows, respectively.

When the precipitates of the high melting point component 3b are independently distributed as in (a) and (b) of FIG.
As shown in (b), a cross section parallel to the film surface of the recording film 3 (hereinafter, referred to as “(3/3)” of the film thickness T of the recording film 3 at a position separated from one interface of the recording film 3 by (Referred to as the first reference cross section), each high melting point component 3 in the first reference cross section
Measure the length of the precipitate in b. Then, the maximum value of the length measured in any direction is defined as "maximum external dimension y".

The "maximum external dimension y" is specifically shown in FIG.
As shown in (a), each high melting point component 3 in the first reference cross section
When the shape of the precipitate of b is circular or close to a circle, it means the diameter of the precipitate, and when it is oval or close to an oval,
It means the major axis of the precipitate, and in the case of a polygon, it means the length of the longest diagonal of the precipitate.

The “height h” means a section perpendicular to the film surface of the recording film 3 (hereinafter referred to as the second reference section), and the recording film of the precipitate of each high melting point component 3b in the second reference section. The length in the direction perpendicular to the film surface of 3 is measured. The length thus obtained is defined as "height h" of the precipitate of the high melting point component 3b.

This "height h" means that "precipitate" of "granular" high melting point component 3b is distributed as shown in FIG. 1 (a), and "columnar shape" as shown in FIG. 1 (b). High melting point ingredient 3
It is applied when the precipitate of b is distributed in contact with both interfaces of the recording film 3.

The "height h '" has the same concept as the above-mentioned "height h", but as shown in FIG. 1 (c), the precipitate of the "columnar" high melting point component 3b is formed on the recording film 3. The only difference is that it is applied when it is distributed in contact with only one interface.

As shown in FIG. 5A, the "center-to-center distance i" means the average value of the distances between the centers of the precipitates of two adjacent high melting point components 3b in the first reference cross section. .

The "maximum pore size p '" is applied when the "porous" high-melting point component 3b is precipitated as shown in FIG. 1 (c), and is the height in the first reference cross section. It means the maximum value of the size of each hole in the precipitate of the melting point component 3b.

This "maximum hole size p '" is, specifically,
As shown in FIG. 6, when the hole shape in the first reference cross section is circular or close to a circle, it means the diameter of the hole, and when it is elliptical or close to an ellipse, it means the long diameter of the hole, and when it is a polygon. Means the length of the longest diagonal of the hole.

The "maximum wall thickness w" is the "maximum hole size p '".
Similarly to the above, the present invention is applied to the case where the “porous” high melting point component 3b is deposited, and as shown in FIG. 6, two adjacent deposits of the high melting point component 3b are present in the first reference cross section. It means the maximum thickness of the wall between the holes.

(Relationship with Size of Precipitate of High Melting Point Component) The relationship between the size of the precipitate of high melting point component defined above and the number of rewritable times is as follows.

First, when the "maximum external dimensions y" of the precipitates of the high melting point component 3b are different, the number of rewritable times and the power of the laser beam are set to 15% higher than the optimum value under severe conditions.
0 C / N of ^five reproduced signal after rewriting, respectively changed as follows. This change in C / N was mainly due to the change in N level.

[0219] From this result, it was found that the maximum outer dimension y of the precipitate of the high melting point component 3b is preferably in the range of 5 nm ≦ d ≦ 80 nm.

Next, as shown in FIG. 4 (a), when the "granular" high melting point component 3b is deposited in the recording film 3, if the "height h" of the deposit is different, the number of rewritable times is It changed as follows.

[0221] In addition, as shown in FIG. 4B, the “columnar” high melting point component 3b
In the case where the deposits were deposited from the interfaces on both sides of the recording film 3, the rewritable number changed as follows when the “height h” of the deposits was different.

[0222] From these results, it was found that in the case of FIGS. 4A and 4B, the height h of the precipitate of the high melting point component 3b is preferably in the range of 10 nm ≦ h.

As shown in FIG. 4C, when the “columnar” high melting point component 3b is deposited from the interface on one side of the recording film 3, if the “height h ′” of the deposit is different, the number of rewritable times is It changed as follows.

[0224] From this result, it was found that in the case of FIG. 4C, the height h ′ of the precipitate of the high melting point component 3b is preferably in the range of 5 nm ≦ h ′.

Next, when the "center-to-center distance i" of the precipitate of the high-melting point component 3b is different, the number of rewritable times and the power of the laser beam are set to 15% higher than the optimum value under severe conditions.
The C / N of the reproduced signal after rewriting ^five times changed as follows. This change in C / N was mainly due to the change in C level.

Number of rewritable times i = 120 nm 8 × 10 ⁴ times i = 90 nm 1.5 × 10 ⁵ times i = 70 nm 1.8 × 10 ⁵ times i = 60 nm 2 × 10 ⁵ times i = 40 nm 2 × 10 ⁵ times i = 15 nm 2 × 10 ⁵ times 10 ⁵ times C / N of reproduced signal after rewriting i = 70 nm 50 dB i = 40 nm 50 dB i = 30 nm 49 dB i = 20 nm 46 dB i = 15 nm 45 dB i = 10 nm 44 dB i = 5 nm 40 dB Therefore, the center distance i of the precipitate of the high melting point component 3b
It was found that the range of 20 nm ≦ i ≦ 90 nm is preferable.

Next, as shown in FIG. 1C, the high melting point component 3
When b was connected in the film surface direction and was deposited in a “porous” state, the rewritable count changed as follows when the “maximum pore size p ′” of the deposit was different.

[0228] From this result, the maximum pore size p ′ of the porous precipitate is
It has been found that a range of p'≤80 nm is preferable.

Subsequently, when the "maximum wall thickness w" of the porous high melting point component 3b is different, the reproduction signal after rewriting 10 ⁵ times under severe conditions with the laser light power being 15% higher than the optimum value. The C / N changed as follows. This change in C / N was mainly due to the change in C level.

C / N w = 5 nm 50 dB w = 15 nm 49 dB w = 20 nm 46 dB w = 35 nm 40 dB of the reproduced signal after rewriting 10 ⁵ times From this result, the maximum wall thickness w of the porous refractory component 3b is , W ≦ 20 nm is preferable.

(Relationship with melting point of high melting point component) When the relationship between the melting point of the high melting point component and the number of rewritable times was examined, the melting point (mp) of the high melting point component 3b deposited in the recording film 3 was different. Then, it was inferred by computer simulation that the number of rewritable times changed as follows.

[0232] From these results, it was found that the melting point of the high melting point component 3b is preferably in the range of 780 ° C or higher, and more preferably in the range of 930 ° C or higher.

If the difference between the melting point of the residual component (phase change component 3a) after the high melting point component 3b is precipitated and the melting point of the high melting point component 3b is different, the number of rewritable times may change as follows. It could be estimated by computer simulation.

Number of rewritable times m. p. Difference = 0 ° C 7 × 10 ⁴ times m. p. Difference = 150 ° C. 1.5 × 10 ⁵ times m.p. p. Difference = 300 ° C. 2 × 10 ⁵ times From this result, the difference in melting point between the high melting point component 3b and the phase change component 3a is preferably 150 ° C. or more, more preferably 300 ° C.
It has been found that the above range is more preferable.

(Relationship between the difference in crystallization temperature between the high melting point component and the phase change component) In order to investigate the relationship between the difference in the crystallization temperature between the high melting point component and the phase change component and the number of rewritable times, the information recording of Example 1 was performed. The temperature of the thin film was raised at a constant rate of 10 ° C./min, and the temperature at which the heat of crystallization started was measured. From the result, when the difference s between the crystallization temperatures of the high-melting point component 3b and the low-melting point component 3a that causes a phase change was obtained, the rewritable number changed as follows due to the temperature difference s.

[0236] From these results, it was found that the difference in melting point between the high melting point component 3b and the phase change component 3a is preferably 10 ° C or higher, more preferably 30 ° C or higher.

(Relationship with High Melting Point Component Deposited During Film Formation) In Example 1, the high melting point component Cr ₄ Te ₅ film was coated in an island shape in the initial step of manufacturing the information recording thin film. The average film thickness z of the high melting point component Cr ₄ Te ₅
Is changed as follows, the number of rewritable times and the power of the laser beam are increased by 15% above the optimum value under severe conditions.
The C / N of the reproduced signal after rewriting ^five times changed as follows. This change in C / N was mainly due to the change in C level.

“Z = 0 nm” means that an island-shaped thin film of high melting point component Cr ₄ Te ₅ was not formed.

Number of rewritable times z = 0 nm 5 × 10 ⁴ times z = 1 nm 1 × 10 ⁵ times z = 5 nm 2 × 10 ⁵ times 10 ⁵ times C / N of the reproduced signal after rewriting z = 1 nm 47 dB z = 5 nm 47 dB z = 10 nm 46 dB z = 20 nm 40 dB From these results, the number of rewritable times increased when the island-shaped thin film of high melting point component Cr ₄ Te ₅ was formed before the initial crystallization step, and the initial crystallization step The average film thickness z of the high melting point component Cr ₄ Te ₅ previously formed in an island shape is 1 nm ≦ z ≦ 10n.
It has been found that a range of m is preferred.

(Protective Layer, Intermediate Layer, Reflective Layer) In this example, both protective layer 2 and intermediate layer 4 were made of ZnS—SiO.
_Although it is formed of _2, it may be formed of other materials. For example, Si-N based material, Si-O-N based material, S
iO ₂ , SiO, TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ , Y ₂ O ₃
Oxides such as TaN, AlN, nitrides such as Al—Si—N-based materials (eg AlSiN ₂ ), ZnS, Sb ₂ S
Sulfides such as _3, selenides such as SnSe _2, Sb ₂ Se _3, can be used fluorides, such as CeF _3. S
i, Ge, TiB ₂ , B ₄ C, B, C or the like may be used. It may have a composition close to that of these materials, or may be a mixed material of these materials. Further, it may be a multi-layer in which layers of these materials are laminated.

When each of the protective layer 2 and the intermediate layer 4 is composed of multiple layers, the first layer of a material containing ZnS in an amount of 70 mol% or more (for example, ZnS—SiO ₂ ) and at least one of Si and Ge are 70 atomic%. A two-layer film including a second layer of the above-described material or a two-layer film including a first layer of a material including 70 mol% or more of ZnS and a second layer of an oxide of Si (eg, SiO ₂ ) is preferable.

In this case, it is preferable that the first layer of a material containing ZnS in an amount of 70 mol% or more is provided on the recording film 3 side and the thickness thereof is 3 nm or more. This is to prevent a decrease in recording sensitivity. The thickness of the first layer is preferably 10 nm or less. S
This is because the flow suppressing effect of the recording film 3 due to the low thermal expansion coefficient of the second layer of i-oxide can be effectively exhibited.

Such a two-layer film is more preferably provided as the protective layer 2, but may be provided as the intermediate layer 4.
When such a two-layer film is provided as the protective layer 2, Si is used.
The thickness of the second oxide layer is preferably 50 nm or more and 250 nm or less. This is because the recording sensitivity is good in this range.

When such a two-layer film is provided as the intermediate layer 4, the thickness of the second layer of Si oxide is preferably 10 nm or more and 80 nm or less. This is because within this range, the recording sensitivity is good and there is a flow suppressing effect.

When the intermediate layer 4 was omitted, the recording sensitivity was reduced by about 30% and the remaining loss was increased by about 5 dB. The number of rewrites also decreased. Therefore, in order to eliminate these difficulties, it is preferable to provide the intermediate layer 4.

When the refractive index of the intermediate layer 4 is in the range of 1.7 or more and 2.3 or less, the film thickness is in the range of 3 nm or more and 100 nm or less, and in the range of 180 nm or more and 400 nm or less, respectively, 50 dB or more. C / N was obtained. Therefore, it is preferable to set the refractive index of the intermediate layer 4 in this range.

In this Example 1, as the reflecting layer 5, Al-
A Ti film is used, but Si is used instead of the Al-Ti film.
A film of -Ge mixed material may be used. In this case, since the light absorptance of the recording mark portion can be made smaller than the light absorptance of the portion other than the recording mark, there is an advantage that the unerased portion due to the difference in the light absorptance can be prevented and the rewritable number does not decrease. The Ge content is preferably in the range of 10 atom% or more and 80 atom% or less from the viewpoint of preventing reduction in the number of rewritable times.

Similar results were obtained with a Si--Sn mixed material or a Si--In mixed material as the material for the reflective layer 5. Similar results were obtained with a material obtained by mixing two or more of these mixed materials.

In addition, Si, Ge, C, Au, Ag, C
u, Al, Ni, Fe, Co, Cr, Ti, Pd, P
A single element of t, W, Ta, Mo, Sb, an alloy containing at least one of these elements as a main component, or a layer made of an alloy of these elements may be used, or a multi-layer made of those layers may be used. Alternatively, a composite layer of these and another substance such as an oxide may be used.

(Substrate, Laminated Structure) In this Example 1, a polycarbonate substrate 1 having irregularities such as tracking guides directly formed on the surface is used, but instead of this,
You may use the chemically strengthened glass etc. which formed the polyolefin, the epoxy, the acrylic resin, and the ultraviolet curing resin layer on the surface.

A laminated structure in which a part of the intermediate layer 4, the reflective layer 5 and the protective layer 2 is omitted, for example, a laminated structure of substrate 1 / protective layer 2 / recording film 3 in which the intermediate layer 4 and the reflective layer 5 are omitted, reflection Layered structure of substrate 1 / recording film 3 / intermediate layer 4 omitting layer 5 and protective layer 2, laminated structure of substrate 1 / recording film 3 / reflective layer 5 omitting intermediate layer 4 and protective layer 2, and the like But
Compared with the conventional one, even if rewriting was performed a large number of 10 ⁵ times, the increase in noise was small and good results were obtained.

(Effect) As described above, this embodiment 1
The information recording thin film can be rewritten many times over 10 ⁵ times while maintaining good recording / reproducing / erasing characteristics. There is also an advantage that the power of laser light used for recording / erasing may be low.

[Example 2] (Structure / Manufacturing Method) The information recording medium of Example 2 has the same recording layer 5 of Ge-Sb-Te-Cr material as Example 1, but has a different composition. 1 has the same configuration as the information recording medium of Example 1 except that a metal layer is provided between the protective layer 2 and the protective layer 2. This information recording medium was formed as follows.

As in Example 1, using a magnetron sputtering apparatus, a metal layer (not shown) made of an Au film (thickness: 15 nm) was formed on the polycarbonate substrate 1 having a tracking groove with a U-shaped cross section on the surface. And a protective layer 2 made of the same (ZnS) ₈₀ (SiO ₂ ) ₂₀ film (thickness 20 nm) as in Example 1 was formed thereon.

Next, on the protective layer 2, a Cr ₄ Te ₅ film (not shown) having the same high melting point component as in Example 1 was formed in an island shape to an average film thickness of 3 nm, and then Ge ₄₅ Te _45. Ge ₄₀ Sb ₁₀ Te ₄₄ Cr ₁₀ near the Cr ₁₀ composition, that is, (Ge ₄₀ Sb
Recording film 3 having a composition of ₁₀ Te _27.5 ) ₂ (Cr ₄ Te ₅ ) ₅
(Thickness 20 nm) was formed. At this time, as in Example 1, the rotary co-sputtering method using a Cr ₄ Te ₅ target and a Ge ₄₀ Sb ₁₀ Te _27.5 target was used.

Next, on the recording film 3, (ZnS) ₈₀ (Si
After the intermediate layer 4 made of the O ₂ ) ₂₀ film (thickness 40 nm) was formed, the reflective layer 5 made of the Au film (thickness 70 nm) was formed thereon in the same magnetron sputtering apparatus. Thus, the first disc member was obtained.

On the other hand, the second disk member having the same structure as the first disk member was formed by the completely same method, and the vinyl chloride-vinyl acetate hot melt adhesive layer 6 was formed.
The reflective layers 5 and 5'of the first and second disk members were bonded to each other via the above to obtain a disk-shaped information recording medium.

In Example 2, the high melting point component was Cr ₄ T.
e ₅ , the phase change component is Ge ₄₀ Sb ₁₀ Te _27.5 .

With respect to the recording film 3 thus obtained, Example 1
After the initial crystallization was performed by the same method as described above, information was recorded / reproduced / erased by the same method as in Example 1, and the same results as in Example 1 were obtained.

Next, with respect to the recording film 3 thus obtained, suitable ranges of the composition ratios a, b, c and d of Ge, Sb, Te and Cr were determined as follows.

(Relationship with Sb composition ratio b: GeTe composition vicinity) In the triangular phase diagram of FIG. 7, the Cr content was fixed (10%) connecting Ge ₄₅ Te ₄₅ Cr ₁₀ and Sb ₉₀ Cr ₁₀ . The composition was changed on a straight line, and the difference in reflectance between when the recording film 3 was amorphized and when it was crystallized was measured. As a result, the following data were obtained.

[0262] From this result, it was found that near the GeTe composition, a high reflectance difference was obtained when the composition ratio b of Sb was in the range of 0 ≦ b ≦ 0.2. Such a high reflectance difference contributes to the improvement of the C / N of the reproduced signal.

Further, compared with the case where Sb does not enter (b = 0), the case where Sb enters within the range of 0.01 ≦ b is
It was found that the laser irradiation power for amorphization can be lowered by 3 mW.

(Relationship between Ge and Te composition ratios a and c: Ge
(Near Te composition) In the triangular phase diagram of Fig. 7, Sb ₁₀ Te ₈₀
By changing the composition on a straight line connecting Cr ₁₀ and Ge ₈₀ Sb ₁₀ Cr ₁₀ and keeping the Cr content constant (10%), the difference in reflectance between when amorphized and when crystallized was calculated. It was measured. As a result, the following data were obtained.

[0265] From this, in the vicinity of the GeTe composition, the Ge and Te composition ratios a and c are 0.25 ≦ a ≦ 0.65 and 0.35.
It was found that a high reflectance difference can be obtained in the range of ≤c≤0.75. Such a high reflectance difference contributes to the improvement of the C / N of the reproduced signal.

(Relationship with Cr composition ratio d: near GeTe composition) The ratio of the composition ratios a, b and c of Ge, Sb and Te, which are the rest of Cr ₄ Te ₅ , is a: b: c = 4: 1. Keep it at 4: C
When the content of r ₄ Te ₅ was changed, the C / N ratio of the reproduced signal after rewriting 10 ⁵ times under severe conditions in which the power of the laser light was increased by 15% from the optimum value was measured. The following results were obtained for d.

Reproduced signal after rewriting 10 ⁵ times C / N d = 0 42 dB d = 0.03 48 dB d = 0.1 50 dB d = 0.2 50 dB d = 0.34 48 dB Further, the power of the laser beam is optimized. Under the strict condition of 15% higher than the value, the number of laser light irradiation for initialization is 200
After the information was recorded once, the "erase ratio" of the reproduced signal when the information was overwritten once was calculated. As a result, Cr
When the composition ratio d of was changed, the "erase ratio" changed as follows. Here, the "erase ratio" is the same as that in the first embodiment.

[0268] From this result, it was found that the erasing ratio decreased as the Cr composition ratio d increased.

Therefore, the Cr composition ratio d is 0.03 ≦ d ≦.
In the range of 0.3, the irradiation time of the laser beam required for erasing can be shortened and the laser beam power is set to 15 or less than the optimum value.
It has been found that the carrier-to-noise ratio (C / N) of the reproduced signal can be improved after rewriting 10 ⁵ times under the strict condition of increasing%.

(Ratio of content of low-melting point component and high-melting point component in recording film) The average composition of the recording film 3 is defined as the low-melting point component L (GeTe) of elemental element or compound and the high melting point of elemental element or compound composition. expressed by component H (Cr ₄ Te ₅₎ by the formula L _j H _k, content k of Cr ₄ Te ₅ is a high melting point component H
When was changed, the jitter after rewriting 10 times under severe conditions in which the laser power was increased by 15% changed as follows.

[0271] After rewriting 10 times the set formed jitter _{(GeTe) 100 (Cr 4 Te} 5) 0 5ns (GeTe) 98 (Cr 4 Te 5) 2 3ns (GeTe) 90 (Cr 4 Te 5) 10 2ns (GeTe _{) 80 (Cr 4 Te 5)} 20 than _{3ns (GeTe) 70 (Cr 4} Te 5) 30 5ns Consequently, the j, k is 0.02 ≦ [k / (j +
It has been found that it is preferable to satisfy the relational expression of k)] ≦ 0.1.

In this case, the recording film 3 has a composition in which j and k satisfy the above relational expressions as a reference composition, and the content of each element of Ge, Te and Cr is ± 10 atomic% with respect to the reference composition. It was also found that it is preferably within the range, more preferably within ± 5 atom%.

The content of Ge in the low melting point component g
(Atomic%) and k, and j is k / (j + k)
It was found that the relational expression of = (2 / g) +0.01 was satisfied.

Items not mentioned here are the same as in the first embodiment.

The second embodiment has an advantage over the first embodiment in that the difference in reflectance between the amorphous recording point formed on the recording film 3 and the other crystalline portion can be increased.

The composition of the recording films 3 and 3 of the information recording medium of Example 2 is expressed by the general formula: (Ge _0.44 Sb _0.11 Te _0.45 ).
_It becomes _0.9 Cr _0.1 , and the additional element X is Cr.

Example 3 The information recording medium of Example 3 is
The structure is the same as that of the information recording medium of Example 1 except that the concentration of the precipitate of the high melting point component 3b has a gradient in the film thickness direction of the recording film 3. This information recording medium was formed as follows.

(Structure / Manufacturing Method) A magnetron sputtering apparatus was used, and a cross section U was formed on the surface in the same manner as in Example 1.
Polycarbonate substrate 1 having a V-shaped tracking groove
After forming a protective layer 2 made of a (ZnS) ₈₀ (SiO ₂ ) ₂₀ film on it, a Cr ₄ Te ₅ film (not shown) which is a high melting point component is formed in an island shape to an average film thickness of 3 nm. , And G
e ₇ Sb ₂₇ Te ₅₇ Cr ₉ , that is, (GeSb ₄ Te ₇ ) ₈
A recording film 3 having a composition of (Cr ₄ Te ₅ ) ₂ was formed. At this time, the Cr ₄ Te ₅ target and Ge as shown below were used.
A rotating simultaneous sputtering method with an Sb ₄ Te ₇ target was used.

Then, (ZnS) ₈₀ (S
After the intermediate layer 4 made of the iO ₂ ) ₂₀ film was formed, the reflective layer 5 made of the Al ₉₇ Ti ₃ film was formed thereon. Thus, the first disc member was obtained.

On the other hand, the second disk member having the same structure as the first disk member was formed by the same method, and the vinyl chloride-vinyl acetate hot melt adhesive layer 6 was formed.
The reflective layers 5 and 5'of the first and second disc members were bonded to each other via the above to obtain a disc-shaped information recording medium of this Example 3.

Also in the third embodiment, as in the first embodiment, the high melting point component is Cr ₄ Te ₅ and the phase change component is GeSb ₄
Te ₇ .

The rotating simultaneous sputtering method using a Cr ₄ Te ₅ target and a GeSb ₄ Te ₇ target was carried out as follows.

First, C having an average film thickness of 3 nm is formed on the protective layer 2.
An r ₄ Te ₅ film is formed in an island shape. Then GeSb ₄
While keeping the voltage applied to the Te ₇ target constant,
The voltage applied to the Cr ₄ Te ₅ target was gradually decreased. The applied voltage sequence at that time is as follows.

[Applied voltage sequence] Spitter time Sputtering power (W) Cr ₄ Te ₅ content from the light incident side (seconds) GeSb ₄ Te ₇ tat Cr ₄ Te ₅ tat Recording film thickness ( nm) (atomic%) 0-9 49 150 0-6 50 10-20 49 100 6-12 40 21-33 49 65 13-13-18 30 34-47 49 40 19-24 24 20 48-63 49 20 24-30 10 By this step, the recording film 3 in which the content (concentration) of the precipitate Cr ₄ Te ₅ of the high melting point component 3b in the recording film 3 was gradually changed in the film thickness direction of the recording film 3 was obtained.

Regarding the recording film 3 thus obtained, Example 1
After the initial crystallization was performed by the same method as described above, information was recorded / reproduced / erased by the same method as in Example 1, and the same results as in Example 1 were obtained.

Items not mentioned here are the same as in the first embodiment.

In the information recording medium of Example 3, as in Examples 1 and 2, the recording film 3 was formed as compared with the recording film in which the content of the high melting point component precipitates was constant in the film thickness direction. Although the process is complicated, there is an advantage that the number of laser irradiation for initialization can be reduced.

Content (concentration) of precipitate of high melting point component 3b
As another film forming method of the recording film 3 in which the film thickness gradually changes, the voltage applied to the GeSb ₄ Te ₇ target is gradually increased while keeping the voltage applied to the Cr ₄ Te ₅ target constant. The method of letting it do may be used.

In the film forming process of the recording film 3, it was found that the recording characteristics were better when the voltage applied to each target was changed as gradually as possible.

In place of the method of changing the voltage applied to each target, an in-line sputtering device was used, and Cr ₄ T
A similar recording film can be produced by using a target in which the area of the e ₅ composition and the area of the GeSb ₄ Te ₇ composition are gradually changed.

Example 4 The information recording medium of Example 4 is
The Ge-Sb-Te-Cr recording film 3 of Example 1 has the same configuration as that of the information recording medium of Example 1, except that Co and Si were used as the additional element X instead of Cr. . This information recording medium was formed as follows.

(Structure / Manufacturing Method) As in Example 1, the same (ZnS) ₈₀ (SiO 2) as in Example 1 (ZnS) ₈₀ (SiO 2) was used on a polycarbonate substrate 1 having a tracking groove with a U-shaped cross section on the surface thereof, using a magnetron sputtering apparatus. ₂ ) A protective layer 2 consisting of ₂₀ films was formed.

Next, a Cr ₄ Te ₅ film (not shown) having the same high melting point as in Example 1 was formed on the protective layer 2 in an island shape to an average film thickness of 3 nm, and then Sb ₂₇ Te ₄₆ was formed. Ge ₇ Co ₁₅
A recording film 3 (thickness: 20 nm) having a composition of Si _5, that is, (GeSb ₄ Te ₇ ) ₈₀ (Co ₃ Si) ₂₀ was formed. At this time, as in Example 1, the Co ₃ Si target and GeS
The rotating simultaneous sputtering method with a b ₄ Te ₇ target was used.

Then, on the recording film 3, (ZnS) ₈₀ (Si
After the intermediate layer 4 made of the O ₂ ) ₂₀ film (thickness 40 nm) was formed, the reflective layer 5 made of the Au film (thickness 70 nm) was formed thereon in the same magnetron sputtering apparatus. Thus, the first disc member was obtained.

On the other hand, a second disk member having the same structure as the first disk member was formed by the exactly same method, and the vinyl chloride-vinyl acetate hot melt adhesive layer 6 was formed.
The reflective layers 5 and 5'of the first and second disk members were bonded to each other via the above to obtain a disk-shaped information recording medium.

In Example 2, the high melting point component was Co ₃ S.
i, the phase change component is GeSb ₄ Te ₇ .

About the recording film 3 thus obtained, Example 1
After the initial crystallization was performed by the same method as described above, information was recorded / reproduced / erased by the same method as in Example 1, and the same results as in Example 1 were obtained.

(Relationship with Composition Ratios a, b, c, d of Ge, Sb, Te, Co ₃ Si) Next, the recording film 3 thus obtained
With respect to Ge, Sb, Te and Co as follows:
The range of suitable composition ratios a, b, c and d of ₃ Si was determined.

When the composition ratio d of Co ₃ Si is changed while maintaining the composition ratio a, b, c of Ge: Sb: Te at a: b: c = 1: 4: 7, , 10 ^{5 under} severe conditions with laser light power 15% higher than the optimum value
The change in C / N of the reproduced signal after rewriting is performed in the first embodiment.
Was similar to.

(Another Example of Phase Change Component) GeSb ₄ Te ₇ which is a phase change component is partially or entirely GeSb ₂ Te ₄ , G
Substitution with at least one of e ₂ Sb ₂ Te ₅ gives substantially similar characteristics.

(Another Example of High Melting Point Component) Part or all of Co ₃ Si, which is a high melting point component, is replaced with Ce ₅ Si ₃ and Ce ₃ S.
i ₂ , Ce ₅ Si ₄ , CeSi, Ce ₃ Si ₅ , CeSi ₂ ,
Cr ₅ Si ₃ , CrSi, CrSi ₃ , CrSi ₂ , Cr ₃
Si, CoSi, CoSi ₂ , NiSi ₂ , NiSi, N
i ₃ Si ₂ , Ni ₂ Si, Ni ₅ Si ₂ , Ni ₃ Si, Pt ₅
Si ₂ , Pt ₂ Si, PtSi, LaSi ₂ , Bi ₂ Ce,
BiCe, Bi ₃ Ce ₄ , Bi ₃ Ce ₅ , BiCe ₂ , Cd
₁₁ Ce, Cd ₆ Ce, Cd ₅₈ Ce ₁₃ , Cd ₃ Ce, Cd ₂
Ce, CdCe, Ce ₂ Pb, CePb, CePb ₃ , C
_{e 3 Sn, Ce 5 Sn 3} , Ce 5 Sn 4, Ce 11 Sn 10, C
_{e 3 Sn 5, Ce 3 Sn} 7, Ce 2 Sn 5, CeSn 3, Ce
_{Zn, CeZn 2, CeZn 3,} Ce 3 Zn 11, Ce 13 Z
_{n 58, CeZn 5, Ce 3} Zn 22, Ce 2 Zn 17, CeZ
n ₁₁ , Cd ₂₁ Co ₅ , CoGa, CoGa ₃ , CoSn,
Cr ₃ Ga, CrGa, Cr ₅ Ga ₆ , CrGa ₄ , Cu ₉
Ga ₄ , Cu ₃ Sn, Cu ₃ Zn, Bi ₂ La, BiLa,
Bi ₃ La ₄ , Bi ₃ La ₅ , BiLa ₂ , Cd ₁₁ La, C
d ₁₇ La ₂ , Cd ₉ La ₂ , Cd ₂ La, CdLa, Ga ₆
La, Ga ₂ La, GaLa, Ga ₃ La ₅ , GaLa ₃ ,
La ₅ Pb ₃ , La ₄ Pb ₃ , La ₁₁ Pb ₁₀ , La ₃ Pb ₄ ,
_{La 5 Pb 4, LaPb 2,} LaPb 3, LaZn, LaZ
_{n 2, LaZn 4, LaZn 5} , La 3 Zn 22, La 2 Zn
₁₇ , LaZn ₁₁ , LaZn ₁₃ , NiBi, Ga ₃ Ni ₂ ,
GaNi, Ga ₂ Ni ₃ , Ga ₃ Ni ₅ , GaNi ₃ , Ni ₃
Sn, Ni ₃ Sn ₂ , Ni ₃ Sn ₄ , NiZn, Ni ₅ Zn
₂₁ , PtBi, PtBi ₂ , PtBi ₃ , PtCd ₂ , P
t ₂ Cd ₉ , Ga ₇ Pt ₃ , Ga ₂ Pt, Ga ₃ Pt ₂ , Ga
Pt, Ga ₃ Pt ₅ , GaPt ₂ , GaPt ₃ , Pt ₃ P
b, PtPb, Pt ₂ Pb ₃ , Pt ₃ Sn, PtSn, P
t ₂ Sn ₃ , PtSn ₂ , PtSn ₄ , Pt ₃ Zn, PtZ
Similar results can be obtained by substituting with n ₂ or the like.

Further, at least one of high-melting point compounds containing two or more elements represented by the above-mentioned element X, compounds having a composition close to that, a mixed composition thereof, or a compound of three or more elements close to the mixed composition. You may replace it with one.

Items not mentioned here are the same as in the first embodiment.

The composition of the recording films 3 and 3 of the information recording medium of Example 4 is expressed by the general formula: (Ge _0.08 Sb _0.33 Te _0.59 ).
_It becomes _0.8 (Co ₃ Si) _0.2 , and the additive element X is Co and Si.

[Embodiment 5] FIG. 8 shows a cross section of a disk-shaped information recording medium of Embodiment 5. This medium is a read-only type in which information is inscribed in the surface of the substrate by irregularities (bits).

(Structure / Manufacturing Method) In the structure of the information recording medium of Example 5, recording bits representing information are formed in advance on the surface of the substrate, and the recording film 3 of Example 1 is used as a mask layer. However, the information recording medium according to the first embodiment is different from the information recording medium according to the first embodiment in other respects. This information recording medium was manufactured by using a magnetron sputtering apparatus in the same manner as in Example 1.

That is, first, on the polycarbonate substrate 11 having the recording bit B formed on the surface thereof, a film having a thickness of about 130 nm (Z
A protective layer 12 made of an nS) ₈₀ (SiO ₂ ) ₂₀ film was formed. Next, an island-shaped Ag ₂ Te film (not shown), which is a high melting point component, is formed on the protective layer 12 to an average film thickness of 3 nm, and then (Ag ₂ Te) ₃₀ (Se) having a film thickness of about 22 nm is formed. _80- T
A mask layer 13 having a composition of e ₂₀ ) ₇₀ , that is, Ag ₂₀ Te ₂₄ Se ₅₆ was formed.

Then, a film thickness of about 40 is formed on the mask layer 13.
Intermediate layer 1 consisting of a (ZnS) ₈₀ (SiO ₂ ) ₂₀ film of nm
4 was formed, and a reflection layer 15 made of an Al ₉₇ Ti ₃ film having a film thickness of 200 nm was further formed. After that, another substrate 11 'was attached to the reflective layer 15 with the adhesive layer 16 to obtain the information recording medium shown in FIG.

Mask layer 13 having a composition of Ag ₂₀ Te ₂₄ Se ₅₆
In the step of forming, the formation of the island-shaped Ag ₂ Te film may be omitted. In this case, the high melting point component precipitated in the mask layer 13 is Ag ₂ Te generated in the initial crystallization.
Will only be.

The mask layer 13 thus obtained was subjected to initial crystallization by the same method as in Example 1, and then information was reproduced by the same method as in Example 1. As a result, 10 ⁵ or more readings were performed. Was possible. The laser light for reading entered from the substrate 11 side.

Due to the initial crystallization, the high melting point component A is formed in the mask layer 13 in the same form as in Example 1 (see FIG. 1).
g ₂ Te is precipitated, and the remaining component (corresponding to the phase change component 3a in FIG. 1) is (Se ₈₀ -Te ₂₀ ).

(Other Examples of High Melting Point Component) As the high melting point component deposited in the mask layer 13, those described in Examples 1 and 2 can be used in addition to Ag ₂ Te.

(Another Example of Residual Component After Precipitation of High Melting Point Component) A part or all of the residual component (Se ₈₀ -Te ₂₀ ) other than the high melting point component is Sn, Pb, Sb, Bi, Te, Zn, C
d, Se, In, Ga, S, Tl, Mg, Tl ₂ Se,
TlSe, Tl ₂ Se ₃ , Tl ₃ Te ₂ , TlTe, InB
i, In ₂ Bi, TeBi, Tl-Se, Tl-Te,
Pb-Sn, Bi-Sn, Se-Te, S-Se, Bi
-Ga, Sn-Zn, Ga- Sn, Ga-In, In 3
SeTe ₂ , AgInTe ₂ , GeSb ₄ Te ₇ , Ge ₂ S
b ₂ Te ₅ , GeSb ₂ Te ₄ , GeB ₄ Te ₇ , GeBi ₂
Te ₄ , Ge ₃ Bi ₂ Te ₆ , Sn ₂ Sb ₆ Se ₁₁ , Sn ₂ S
b ₂ Se ₅ , SnSb ₂ Te ₄ , Pb ₂ Sb ₆ Te ₁₁ , CuA
sSe ₂ , Cu ₃ AsSe ₃ , CuSbS ₂ , CuSbSe
₂ , InSe, Sb ₂ Se ₃ , Sb ₂ Te ₃ , Bi ₂ Te ₃ ,
SnSb, FeTe, Fe ₂ Te ₃ , FeTe ₂ , ZnS
b, Zn ₃ Sb ₂ , VTe ₂ , V ₅ Te ₈ , AgIn ₂ , Bi
Almost the same characteristics can be obtained by substituting a material containing at least one of Se, InSb, In ₂ Te, and In ₂ Te ₅ as a main component or a material having a composition close to that.

The remaining component is preferably a metal, compound or alloy having a melting point of 650 ° C or lower.

(Principle of Reading Recording Mark) Next, referring to FIG.
The principle of reading the recording mark of the information recording medium of FIG. 8 using the “super-resolution effect” will be described with reference to FIG.

In FIG. 9, 31 is a light spot such as a laser beam, and 32a and 32b are recording marks formed on the surface of the substrate 11. The light spot diameter is defined as the diameter of the light beam at the position where the light intensity becomes (1 / e ² ) of its peak intensity. The minimum pitch of the recording marks 32a and 32b is set smaller than the radius a of the light spot 31.

When the surface of the substrate 11 is irradiated with the laser beam, the irradiated portion is heated, but the medium is constantly moving, so that the high temperature region 35 is displaced from the light spot 31 as shown in FIG. Is formed. In the high temperature region 35, at least the remaining component (component corresponding to the phase change component of Example 1) other than the high melting point component melts, so that the real part n or the imaginary part (extinction coefficient) of the complex refractive index of the mask layer 13 is melted. k decreases, and it becomes difficult for laser light to pass through. Since the crystallized solid state remains in a portion not irradiated with laser light, that is, in a portion other than the high temperature region 35, such a change in complex refractive index does not occur.

Therefore, although there are two recording marks 32a and 32b in the light spot 31, since the recording mark 32b in the high temperature region 35 is hidden by the mask layer 13, only the recording mark 32a is actually used. Is detected. In other words, the actual detection range (aperture) 3
As shown in FIG. 9, the area 4 is a crescent-shaped area (overlapping portion of the light spot 31 and the high temperature area 35) excluding the area 33 that functions as a mask from the circular area of the light spot 31. In this way, the recording marks 32a and 32b smaller than the light spot diameter can be accurately distinguished and read.

By changing the film thickness of each of the protective layer 12, the mask layer 13, the intermediate layer 14 and the reflective layer 15, the light spot 3 can be obtained.
It is also possible to mask only the area below the shaded area in 1.

The melting point of the remaining components of the mask layer 13 is 250 ° C.
In the following case, if the melting point of the high-melting point component is 450 ° C. or higher, the same characteristics as this can be obtained.

(Relationship with change amount of extinction coefficient of mask layer)
Recording mark 3 having a length of about 25% of the diameter of the light spot 31
When 2a and 32b are formed, the change amount Δk ′ of the extinction coefficient k of the mask layer 13 before and after the laser light irradiation.
Changes, C / of the reproduced signal after reading 10 ⁵ times
N changed as follows.

C / N Δk ′ = 5% 37 dB Δk ′ = 10% 42 dB Δk ′ = 20% 46 dB Δk ′ = 30% 48 dB of the reproduced signal after reading 10 ⁵ times. As a result, the extinction coefficient of the mask layer 13 is shown. Change in k Δ
It was found that k ′ is preferably in the range of 20% ≦ Δk ′.

(Relationship with Melting Point of Remaining Component of Mask Layer) Melting point (m.p.
p. ) Has changed, the C / N of the reproduced signal after reading 10 ⁵ times changed as follows.

C / N of reproduced signal after 10 ⁵ times reading m. p. = 100 ° C. 49 dB m.p. p. = 250 ° C. 48 dB m.p. p. = 400 ° C. 47 dB m.p. p. = 650 ° C. 46 dB m.p. p. = 700 ° C. 40 dB m.p. p. = 750 ° C 33 dB From this result, the melting point of the remaining component after the high melting point component is precipitated is 6
It was found that the temperature is preferably 50 ° C or lower, more preferably 250 ° C or lower.

(Others) In the information recording medium of FIG. 8, information is recorded on only one side, but the protective layer 12, the mask layer 13, the intermediate layer 14, and the reflective layer 15 are formed on one side of the substrate 11 '.
If the reflective layer 15 is formed and the reflective layer 15 and the adhesive layer 16 formed on the substrate 11 are bonded together, information can be recorded on both sides of the information recording medium.

[Embodiment 6] FIG. 10 shows that by adding the same mask layer as in Embodiment 5 to the phase-change type disc-shaped information recording medium of Embodiment 1, the "super-resolution effect" is exhibited at the time of reproducing information. Is made available.

The information recording medium of FIG. 10 has the same structure as the information recording medium of Example 1 except that the structure of the recording film is different. That is, the protective layers 22 and 22 'made of the (ZnS) ₈₀ (SiO ₂ ) ₂₀ film are formed on the polycarbonate substrates 21 and 21' similar to those in Example 1, and the protective layers 22 and 22 'are formed on the protective layers 22 and 22'. Are recording films 23, 23 'and (Z
nS) ₈₀ (SiO ₂ ) ₂₀ intermediate layer 24, 24 '
And the reflective layers 25 and 25 'made of Al ₉₇ Ti ₃ film,
Each is formed. The reflective layers 25 and 25 'are
They are attached by the adhesive layer 26.

As shown in FIG. 10, the recording film 23 includes a mask layer 23a and a dielectric layer 2 which are sequentially arranged from the substrate 21 side.
3b and the recording layer 23c. Recording film 2
3'has the same structure as the recording film 23.

The mask layer 23a is the same as that of the fifth embodiment (Ag
₂ Te) ₃₀ (Se ₈₀ -Te ₂₀ ) _70, that is, Ag ₂₀ Te ₂₄
It has a composition of Se ₅₆ and has the same masking function as in Example 5.

The dielectric layer 23b is made of (ZnS) ₈₀ (Si
It is formed of an O ₂ ) ₂₀ film and has the same function as the intermediate layer.

The recording layer 23c may be the same as the recording films 3 and 3'of the first embodiment, or any phase change type recording layer may be used.

This information recording medium is manufactured by using a magnetron sputtering apparatus in the same manner as in Example 1.

A recording mark having a length of 0.4 μm is set to 0.8 μm.
When formed in a cycle, the C / N of the reproduced signal obtained is 46.
The erasure ratio was 25 dB or more.

The mask layer 23a is the same in the conventional information recording medium other than the information recording thin film of the present invention, which records by phase change, and in the information recording medium based on the recording principle other than phase change such as magneto-optical disk. Have an effect.

Regarding points not mentioned in this embodiment,
This is the same as in the first embodiment.

[Embodiment 7] The disc-shaped information recording medium of Example 7 is the same as that of the phase-change type disc-shaped information recording medium of Example 1 except that the reflective layers 5 and 5'are made of Al- of Example 1.
In place of the Ti film, the recording films 3 and 3'containing the high melting point component of the first embodiment are used, and like the sixth embodiment, the "super-resolution effect" can be used when reproducing information. It was done.

The disc-shaped information recording medium of Example 7 is the same as the information recording medium of Example 1 shown in FIG.
Protective layers 2 and 2 ', recording films 3 and 3', and intermediate layers 4 and 4'are sequentially formed on 1 ', and reflective layers 5 and 5'are further formed on these intermediate layers 4 and 4'. Second recording films 3 and 3 ′ are formed respectively.

This information recording medium is manufactured by using a magnetron sputtering apparatus in the same manner as in Example 1.

The recording films 3 and 3 ′ and the reflection layers 1 and 1 ′ thus obtained were subjected to initial crystallization by the same method as in Example 1, and then information was recorded / reproduced / reproduced by the same method as in Example 1.
When erasing was performed, the same results as in Example 1 were obtained.

For example, as the reflective layers 5 and 5 ', a film thickness of 80
When a (LaBi) ₃₀ Bi ₇₀ layer of nm is used, a super-resolution effect at the time of reading is obtained, and when a recording mark having a length of 0.4 μm is written in a 0.8 μm cycle, the C of the reproduced signal obtained is obtained. / N was 46 dB or more, and the erasing ratio was 25 dB or more.

By initial crystallization, (LaBi) ₃₀ Bi ₇₀
In the recording films 3 and 3 ′ and the reflective layers 5 and 5 ′, which are made of the same material, the high melting point component L is formed in the same form as in Example 1 (see FIG. 1).
aBi was deposited. The remaining component (phase change component 3a in FIG. 1) was Bi.

Regarding the remaining components after the high melting point components in the reflective layers 5 and 5'are deposited, metals, compounds or alloys having a melting point of 650 ° C or lower are preferable. This is because there is a large difference between the melting point of the high melting point component and the melting point.

When the melting point of the remaining component is 350 ° C. or lower and the melting point of the high melting point compound is 450 ° C. or higher, almost the same characteristics are obtained.

The real part n or the imaginary part (extinction coefficient) k of the complex refractive index changes by 20% or more due to the irradiation of the laser beam, and the reflectance R is 60 when the real part n and the imaginary part k are high. % Or more is preferable. This is because the recording sensitivity is high.

Part or all of Bi, which is the remaining component of the high-melting point component LaBi, is replaced with Sn, Pb, Sb, Te, Zn, C.
d, Se, In, Ga, S, Tl, Mg, Tl ₂ Se,
TlSe, Tl ₂ Se ₃ , Tl ₃ Te ₂ , TlTe, InB
i, In ₂ Bi, TeBi, Tl-Se, Tl-Te,
Pb-Sn, Bi-Sn, Se-Te, S-Se, Bi
-Ga, Sn-Zn, Ga- Sn, Ga-In, In 3
SeTe ₂ , AgInTe ₂ , GeSb ₄ Te ₇ , Ge ₂ S
b ₂ Te ₅ , GeSb ₂ Te ₄ , GeBi ₄ Te ₇ , GeBi
₂ Te ₄ , Ge ₃ Bi ₂ Te ₆ , Sn ₂ Sb ₆ Se ₁₁ , Sn ₂ S
b ₂ Se ₅ , SnSb ₂ Te ₄ , Pb ₂ Sb ₆ Te ₁₁ , CuA
sSe ₂ , Cu ₃ AsSe ₃ , CuSbS ₂ , CuSbSe
₂ , InSe, Sb ₂ Se ₃ , Sb ₂ Te ₃ , Bi ₂ Te ₃ ,
SnSb, FeTe, Fe ₂ Te ₃ , FeTe ₂ , ZnS
b, Zn ₃ Sb ₂ , VTe ₂ , V ₅ Te ₈ , AgIn ₂ , Bi
Even if replaced by a material containing at least one of Se, InSb, In ₂ Te, In ₂ Te ₅ , etc. as a main component,
Almost similar characteristics can be obtained.

(Principle of Super Resolution Effect) The principle of obtaining the super resolution effect at the time of reading is as follows.

As shown in FIG. 9, in the high temperature region 35 in the light spot 31, at least the phase change component (for example, Bi) in the reflective layers 5 and 5'is melted and the real part n or the complex refractive index thereof is increased. At least one of the imaginary parts k decreases. Therefore, the reflected light in the range 33 that functions as the mask in FIG. 9 becomes weak, and the reflected light from this range 33 becomes the recording film 3, 3 ′.
To provide sufficient contrast for reading.

On the other hand, in the low temperature region of the crystallized solid state, at least one of the real number part n and the imaginary number part k of the complex refractive index is larger than that in the high temperature region, so that sufficient contrast for reading can be provided.

As a result, the detection range (aperture) 34
9 has a crescent shape as shown in FIG. 9, and it becomes possible to reliably read the recording marks 32 recorded at high density in a cycle equal to or smaller than the diameter of the light spot 31.

The size of the detection range 34 can be changed by changing the film thicknesses of the protective layers 2, 2 ', the recording films 3, 3', the intermediate layers 4, 4'and the reflective layers 5, 5 '. .

Items not mentioned here are the same as in the first embodiment.

(Others) Reflective layers 5, 5'of this Example 7
Can also be applied to media based on other recording principles, such as conventional optical recording media for recording by phase change without using the information recording thin film of the present invention, and magneto-optical recording media.

[0353]

According to the information recording thin film, the information recording medium and the method of using the same of the present invention, it is possible to rewrite a large number of times (for example, 10 ⁵ times) while maintaining good recording / reproducing characteristics. .

Further, by utilizing the super-resolution effect, a good number of times (for example, 10 ⁵ times) can be achieved while maintaining good reproduction characteristics.
Can be read.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a recording thin film of an embodiment of an information recording medium of the present invention, (a) shows a granular high melting point component deposited, and (b) shows a columnar high melting point component deposited. ,
(C) shows a porous high melting point component deposited.

FIG. 2 is a triangular phase diagram of an example of a recording layer of the information recording thin film of the present invention.

FIG. 3 is an overall sectional view of an embodiment of the information recording medium of the present invention.

4 shows an embodiment of the information recording medium of the present invention, FIG.
It is a fragmentary sectional view similar to FIG.

FIG. 5 is a partial cross-sectional view of an embodiment of the information recording medium of the present invention, (a) is a cross-sectional view taken along the line D-D of (b), (b).
FIG. 3 is a partial sectional view of the information recording medium.

6 shows an embodiment of the information recording medium of the present invention, FIG.
It is a fragmentary sectional view similar to FIG.

FIG. 7 is a triangular phase diagram of another embodiment of the recording layer of the information recording thin film of the present invention.

FIG. 8 is an overall sectional view of another embodiment of the information recording medium of the present invention.

FIG. 9 is a diagram for explaining the principle of super-resolution effect.

FIG. 10 is an overall sectional view of still another embodiment of the information recording medium of the present invention.

[Explanation of symbols]

 1,1 'Substrate 2,2' Protective layer 3,3 'Recording film 3a Phase change component (residual component) 3b High melting point component 4,4' Intermediate layer 5,5 'Reflective layer 6 Adhesive layer 11, 11' Substrate 12 Protective Layer 13 Recording Film 14 Intermediate Layer 15 Reflective Layer 16 Adhesive Layer 21,21 'Substrate 22, 22' Protective Layer 23, 23 'Recording Film 23a' Mask Layer 23b 'Dielectric Layer 23c' Recording Layer 24, 24 ' Intermediate layer 25, 25 'Reflective layer 26 Adhesive layer 31 Light spots 32a, 32b Recording mark 33 Range working as mask 34 Detection range (aperture) 35 High temperature area B Recording bit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Nishida 1-280 Higashi Koikekubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd.

Claims (72)

[Claims] 1. A thin film for information recording, which is formed on a substrate directly or through a protective layer and records / reproduces information by an atomic arrangement change caused by irradiation of an energy beam, the thin film of the information recording film. The average composition in the thickness direction is represented by the general formula (Ge _a Sb _b Te _c ) _1-d X _d, where X is Cr, Ag, Ba, Co, Ni, Pt, Si,
Sr, Au, Cd, Cu, Li, Mo, Mn, Zn, A
1, Fe, Pb, Na, Cs, Ga, Pd, Bi, S
n, Ti, V, In, W, Zn and at least one element selected from the group consisting of lanthanoid elements, wherein a, b, c and d are each 0.01 ≦ a ≦
0.67, 0.01 ≦ b ≦ 0.59, 0.25 ≦ c
An information recording thin film having a range of ≤ 0.97 and 0.03 ≤ d ≤ 0.3. 2. The values a, b and c are each 0.0
2 ≦ a ≦ 0.19, 0.04 ≦ b ≦ 0.4, 0.5
The information recording thin film according to claim 1, wherein the range is ≤c≤0.75. 3. A, b and c are each 0.2
5 ≦ a ≦ 0.65, 0.01 ≦ b ≦ 0.2, 0.3
The information recording thin film according to claim 1, wherein the range is 5 ≦ c ≦ 0.75. 4. An information recording thin film, which is formed directly on a substrate or through a protective layer and records / reproduces information by a change in atomic arrangement caused by irradiation of an energy beam, wherein the average of the information recording thin films. The composition is Ge, Sb, Te,
Cr, Ag, Ba, Co, Ni, Pt, Si, Sr, A
u, Cd, Cu, Li, Mo, Mn, Zn, Al, F
e, Pb, Na, Cs, Ga, Pd, Bi, Sn, T
i, V, In, W, Zn and a low melting point component L having a relatively low melting point, which is composed of at least one element or compound composed of at least one element selected from the group consisting of lanthanoid elements, and said element A low melting point component L and a high melting point component H, which are composed of at least one simple substance or compound composed of at least one element selected from the group and have a relatively high melting point. When the average composition of and is represented by a composition formula of L _j H _k , the concentration g (atomic%) of Ge in the low melting point component L and the above j and k are k / (j + k) = (2 / g ) +0.01 is used as a standard composition, and the content of each element in the film is within the range of ± 10 atom% determined by the above relational expression. . 5. An information recording thin film, which is formed on a substrate directly or through a protective layer and records and reproduces information by an atomic arrangement change caused by irradiation of an energy beam, wherein the average of the information recording thin films. The composition is composed of a low melting point component L having a relatively low melting point and a high melting point component H having a relatively high melting point, and the low melting point component L has constituent elements of Ge, Sb and Te.
And having a relatively low melting point, the high melting point component H is Ge, Sb, Te, Cr, Ag,
Ba, Co, Ni, Pt, Si, Sr, Au, Cd, C
u, Li, Mo, Mn, Zn, Al, Fe, Pb, N
a, Cs, Ga, Pd, Bi, Sn, Ti, V, In,
It is composed of at least one element selected from W and Zn and is composed of at least one element or compound having a relatively high melting point, and the average composition of the low melting point component L and the high melting point component H. Is expressed by a composition formula of L _j H _k , the concentration g (atomic%) of Ge in the low melting point component L and j and k are k / (j + k) = (2 / g) +0.01 The information recording thin film is characterized in that the content of each element in the film is within the range of ± 10 atom% determined by the above relational formula, with the composition satisfying the relational formula of (1) as a reference composition. 6. The low melting point component L is GeSb ₄ Te ₇ ,
Claim 4 or 5 wherein the refractory component H is Cr ₄ Te ₅
A thin film for recording information according to. 7. The information recording thin film according to claim ₄ , wherein the low melting point component L is GeSb ₄ Te ₄ and the high melting point component H is Cr ₄ Te ₅ . 8. The low melting point component L is Ge ₂ Sb ₂ Te ₅ ,
Claim 4 or 5 wherein the refractory component H is Cr ₄ Te ₅
The information recording thin film described in 1. 9. An information recording thin film, which is formed on a substrate directly or through a protective layer and records / reproduces information by an atomic arrangement change caused by irradiation of an energy beam, wherein the information recording thin film is formed. The average composition in the thickness direction is represented by the general formula (Ge _a Te _c ) _1-d X _d, where X is Cr, Ag, Ba, Co, Ni, Pt, Si,
Sr, Au, Cd, Cu, Li, Mo, Mn, Zn, A
1, Fe, Pb, Na, Cs, Ga, Pd, Bi, S
n, Ti, V, In, W, Zn and at least one element selected from the group consisting of lanthanoid elements, wherein a, c and d are each 0.01 ≦ a ≦ 0.6.
7, 0.25 ≦ c ≦ 0.97, 0.03 ≦ d ≦ 0.
A thin film for recording information, which is in the range of 3. 10. The a and c are each 0.25.
The information recording thin film according to claim 9, wherein the range is ≦ a ≦ 0.65, 0.35 ≦ c ≦ 0.75. 11. The average composition of the information recording thin film is composed of a low melting point component L having a relatively low melting point and a low melting point component H having a relatively high melting point, wherein the low melting point component L is Ge, Te, Cr, Ag, Ba,
Co, Ni, Pt, Si, Sr, Au, Cd, Cu, L
i, Mo, Mn, Zn, Al, Fe, Pb, Na, C
s, Ga, Pd, Bi, Sn, Ti, V, In, W, Z
n and a lanthanoid element, which is composed of at least one element or compound composed of at least one element selected from the group consisting of n and lanthanoid elements, and has a relatively low melting point, and the high melting point component H is selected from the above element group. Is composed of at least one element or compound composed of at least one element, and has a relatively high melting point, and the average composition of the low melting point component L and the high melting point component H is L _j H _k When expressed by a composition formula, the composition in which j and k satisfy the relational expression 0.02 ≦ [k / (j + k)] ≦ 0.2 is used as a reference composition, and the content of each element in the film is as described above. 11. The information recording thin film according to claim 9, which is within a range of ± 10 atom% determined by a relational expression. 12. An information recording thin film, which is formed on a substrate directly or through a protective layer, for recording / reproducing information by an atomic arrangement change caused by irradiation of an energy beam, wherein the information recording thin film is formed. The average composition in the thickness direction is represented by the general formula (Sb _b Te _c ) _1-d X _d, where X is Cr, Ag, Ba, Co, Ni, Pt, Si,
Sr, Au, Cd, Cu, Li, Mo, Mn, Zn, A
1, Fe, Pb, Na, Cs, Ga, Pd, Bi, S
n, Ti, V, In, W, Zn and at least one element selected from the group consisting of lanthanoid elements, wherein b, c and d are each 0.01 ≦ b ≦ 0.5.
9, 0.25≤c≤0.97, 0.03≤d≤0.
A thin film for recording information, which is in the range of 3. 13. The average composition of the information recording thin film is composed of a low melting point component L having a relatively low melting point and a low melting point component H having a relatively high melting point, and the low melting point component L is Sb, Te, Cr, Ag, Ba,
Co, Ni, Pt, Si, Sr, Au, Cd, Cu, L
i, Mo, Mn, Zn, Al, Fe, Pb, Na, C
s, Ga, Pd, Bi, Sn, Ti, V, In, W, Z
n and a lanthanoid element, and at least one element or compound composed of at least one element selected from the group consisting of elements and having a relatively low melting point, and the high melting point component H is selected from the above element group. Is composed of at least one element or compound composed of at least one element, and has a relatively high melting point, and the average composition of the low melting point component L and the high melting point component H is L _j H _k When expressed by a composition formula, the above j and k satisfy the relational expression of 0.05 ≦ [k / (j + k)] ≦ 0.4 as a reference composition, and the content of each element in the film is as described above. 13. The information recording thin film according to claim 12, which is within a range of ± 10 atom% determined by the relational expression. 14. The average composition of the information recording thin film has a composition that satisfies the relational expression as a reference composition, and the content of each element in the film is within a range of ± 5 atom% determined by the relational expression. The information recording thin film according to any one of claims 4 to 8 or claim 11 or 13. 15. The information recording thin film according to claim 1, wherein the element X has a concentration gradient in the film thickness direction of the information recording thin film. 16. A deposit containing a high melting point component having a relatively higher melting point than the remaining component of the information recording thin film, and the deposit containing the element X.
16. The information recording thin film according to claim 6, or the information recording thin film according to claim 6. 17. The non-continuous film having an average film thickness of 1 to 10 nm is present in the vicinity of the light incident side interface of the information recording thin film, wherein at least a part of the high melting point component precipitate is present. Alternatively, the information recording thin film according to item 16. 18. At least a part of the precipitate of the high melting point component is present in the vicinity of the interface on the side opposite to the light incident side of the information recording thin film as a discontinuous film in the range of an average film thickness of 1 to 10 nm. The information recording thin film according to claim 5 or 16. 19. The information recording thin film according to claim 5, wherein the content of the high melting point component changes in the film thickness direction of the information recording thin film. 20. The content of the high melting point component is changed so as to be 50% near the interface on the light incident side of the information recording thin film and 10% near the interface on the opposite side. Item 20. An information recording thin film according to any one of items 16 to 19. 21. The sum of the number of atoms of the constituent elements of the high melting point component is in the range of 10 to 50% with respect to the sum of the number of all the constituent elements of the information recording thin film. The information recording thin film according to any one of 16 to 20. 22. The thin film for information recording according to claim 5, wherein the high melting point component has a melting point of 780 ° C. or higher. 23. The information recording thin film according to claim 5, wherein the difference between the melting point of the high melting point component and the melting point of the remaining component of the thin film is 150 ° C. or more. 24. The thin film for information recording according to claim 5 or any one of claims 16 to 23, wherein the precipitate of the high melting point component is distributed in a granular or columnar shape inside the thin film for information recording. 25. The maximum outer dimension of the precipitate of the high melting point component in the film surface direction of the information recording thin film is 5 nm or more, 8
The information recording thin film according to claim 24, which has a thickness of 0 nm or less. 26. The precipitate of the high melting point component extends in a column shape in the film thickness direction from both interfaces of the information recording thin film, and the precipitate has a length in the film thickness direction of 5 nm or more,
26. The information recording thin film according to claim 24, which has a thickness (1/2) or less of the thickness of the information recording thin film. 27. The precipitate of the high melting point component extends in a columnar shape in the film thickness direction from one interface of the information recording thin film, and the length of the precipitate in the film thickness direction is 10 nm or more, The information recording thin film according to claim 24 or 25, which has a thickness equal to or less than the thickness of the information recording thin film. 28. The length of the precipitate of the high melting point component in the film thickness direction of the information recording thin film is 10 nm or more, and is less than or equal to the film thickness of the information recording thin film.
The information recording thin film according to item 5. 29. A straight line connecting the centers of two adjacent precipitates of the high melting point component has a length of 20 nm or more passing through a region between the precipitates in the film surface direction of the information recording thin film, 29. The information recording thin film according to claim 24, having a thickness of 90 nm or less. 30. A porous precipitate composed of a high melting point component having a relatively higher melting point than the residual component of the information recording thin film is contained, and the residual component is distributed in the pores of the porous precipitate. The information recording thin film according to any one of claims 5 and 16 to 23. 31. The maximum pore size of the pores of the porous precipitate of the high melting point component in the film surface direction of the information recording thin film is 8
The maximum wall thickness in the film surface direction of the information recording thin film in the area between the two adjacent holes is 20 nm or less.
The information recording thin film according to claim 30, having a thickness of not more than nm. 32. The melting point of the remaining component of the information recording thin film is 650 ° C. or lower, or 16 to 31.
The information recording thin film as described in any one of 1. 33. The melting point of the residual component of the information recording thin film is 250 ° C. or lower, or 16 to 31.
The information recording thin film as described in any one of 1. 34. At least one of a real number part and an imaginary number part of a complex refractive index of the information recording thin film changes by 20% or more with respect to that before irradiation by light irradiation.
33. The information recording thin film as described in 33. 35. An information recording thin film, which is formed directly on a substrate or through a protective layer and records or reproduces information by a change in atomic arrangement caused by irradiation of an energy beam, and the remaining of the information recording thin film. A thin film for information recording, characterized in that it contains a precipitate consisting of a high melting point component having a relatively higher melting point than that of the component, and the precipitate is distributed in the region consisting of the remaining components of the information recording thin film. . 36. The maximum outer dimension of the precipitate of the high melting point component in the film surface direction of the information recording thin film is 5 nm or more, 8
36. The information recording thin film according to claim 35, having a thickness of 0 nm or less. 37. The precipitate of the high melting point component extends in a column shape in the film thickness direction from both interfaces of the information recording thin film, and the length of the precipitate in the film thickness direction is 5 nm or more,
The information recording thin film according to claim 35 or 36, which has a thickness (1/2) or less of the thickness of the information recording thin film. 38. The precipitate of the high melting point component extends in a columnar shape in the film thickness direction from one interface of the information recording thin film, and the precipitate has a length in the film thickness direction of 10 nm or more, 35. The thickness of the information recording thin film is less than or equal to the film thickness.
37. An information recording thin film as described in 37. 39. The information recording thin film according to claim 35, wherein the length of the precipitate of the high melting point component in the film thickness direction is not less than 10 nm and not more than the film thickness of the information recording thin film. . 40. A straight line connecting the centers of two adjacent precipitates of the high melting point component has a length of 20 nm or more and 90 nm passing through a region between the precipitates in the film surface direction of the information recording thin film. 40. The information recording thin film according to claim 35, wherein: 41. An information recording thin film, which is formed on a substrate directly or through a protective layer and records or reproduces information by a change in atomic arrangement caused by irradiation with an energy beam, and the remaining of the information recording thin film. Characterized in that it contains a porous precipitate composed of a high melting point component having a relatively higher melting point than the component, and the remaining component of the information recording thin film is distributed in the pores of the porous precipitate. Thin film for information recording. 42. The average composition of the information recording thin film comprises a low melting point component L having a relatively low melting point and a high melting point component H having a relatively high melting point, and the low melting point component L is Ge. , Sb, Te, Cr, Ag,
Ba, Co, Ni, Pt, Si, Sr, Au, Cd, C
u, Li, Mo, Mn, Zn, Al, Fe, Pb, N
a, Cs, Ga, Pd, Bi, Sn, Ti, V, In,
The high melting point component H is composed of at least one element or compound composed of at least one element selected from the group consisting of W, Zn and lanthanoid elements, and has a relatively low melting point. It is composed of at least one element or compound composed of at least one element selected from the group consisting of at least one element, has a relatively high melting point, and has an average composition of the low melting point component L and the high melting point component H as L _j H _When expressed by the composition formula of _k , the concentration g (atomic%) of Ge in the low melting point component and the above j and k satisfy the relational expression of k / (j + k) = (2 / g) +0.01 42. The information recording thin film according to claim 41, wherein the composition is a standard composition, and the content of each element in the film is within a range of ± 10 atom% determined by the relational expression. 43. The low melting point component L is GeSb ₄ Te ₇ ,
The information recording thin film according to claim 42, wherein the high melting point component H is Cr ₄ Te ₅ . 44. The low melting point component L is GeSb ₄ Te ₄ ,
The information recording thin film according to claim 42, wherein the high melting point component H is Cr ₄ Te ₅ . 45. The low melting point component L is Ge ₂ Sb ₂ T.
e ₅ and the high melting point component H is Cr ₄ Te _5.
A thin film for recording information according to. 46. The average composition of the information recording thin film has a composition that satisfies the relational expression as a reference composition, and the content of each element in the film is within a range of ± 5 atom% determined by the relational expression. The information recording thin film according to any one of claims 42 to 45. 47. The maximum inner dimension in the film surface direction of the information recording thin film of the pores of the porous precipitate of the high melting point component is 8
The maximum wall thickness in the film surface direction of the information recording thin film in the area between the two adjacent holes is 20 nm or less.
The information recording thin film according to any one of claims 41 to 46, which has a thickness of not more than nm. 48. The information recording thin film according to claim 35, wherein the melting point of the residual component of the information recording thin film is 650 ° C. or lower. 49. The information recording thin film according to claim 35, wherein the melting point of the residual component of the information recording thin film is 250 ° C. or lower. 50. At least one of a real number part and an imaginary number part of a complex refractive index of the information recording thin film changes by 20% or more with respect to that before irradiation by light irradiation.
49. The information recording thin film as described in any one of 49 to 49. 51. The sum of the number of atoms of the constituent elements of the high melting point component is 10 with respect to the sum of the number of all atoms of the information recording thin film.
The information recording thin film according to any one of claims 35 to 50, which is in the range of -50%. 52. The information recording thin film according to claim 35, wherein the high melting point component has a melting point of 780 ° C. or higher. 53. The information recording thin film according to claim 35, wherein a difference between the melting point of the high melting point component and the melting point of the remaining component of the information recording thin film is 150 ° C. or more. 54. The element according to claim 1, wherein the element X is Cr.
35. The information recording thin film according to any one of claims 6 to 34. 55. The element X is Mo, Si, Pt, C
The thin film for information recording according to any one of claims 1 to 4 or any one of claims 6 to 34, which is one selected from the group consisting of o, Mn and W. 56. The method of manufacturing a thin film for information recording according to claim 1, wherein the raw material thin film is formed on the substrate directly or via a protective layer, and the raw material thin film is energized. A step of irradiating a beam to generate or grow a high melting point component in the raw material thin film to obtain the information recording thin film, and a method for manufacturing the information recording thin film. 57. The method for producing an information recording thin film according to claim 56, wherein in the step of producing or growing the high melting point component in the raw material thin film, the content of the high melting point component is changed in the film thickness direction. . 58. The method for producing a thin film for information recording according to claim 35, wherein the high melting point component material or the high melting point component is directly formed on a substrate or through a protective layer. Depositing a material having a composition close to that of the composition to form an island-shaped seed crystal, depositing a material containing the high melting point component and the residual component on the seed crystal, and forming the high melting point component Selectively growing on the seed crystal and growing the residual component so as to fill the space between the seed crystals. 59. The method for producing an information recording thin film according to claim 58, wherein in the step of selectively growing the high melting point component, the content of the high melting point component is changed in the film thickness direction. 60. An information recording medium comprising the information recording thin film according to claim 1 as a recording layer. 61. An information recording medium comprising the information recording thin film according to claim 35 as a mask layer for super-resolution reading. 62. An information recording medium according to claim 60 or 61, wherein the information recording thin film according to any one of claims 35 to 55 is provided as a reflective layer for super-resolution reading. 63. A mask layer for super-resolution reading, comprising the information recording thin film according to claim 1 as a recording layer, and the information recording thin film according to any one of claims 35 to 55. An information recording medium having the following features. 64. An information recording thin film according to any one of claims 1 to 55 is provided as a recording layer, and the information recording thin film according to any one of claims 35 to 55 is a reflective layer for super-resolution reading. An information recording medium having the following features. 65. The information recording medium according to claim 60, wherein the melting point of the residual component after the precipitation of the high melting point component is 650 ° C. or lower. 66. The information recording medium according to claim 62, wherein the reflectance of the reflective layer is 60% or more. 67. The information recording medium according to claim 62, wherein the thickness of the reflective layer is 150 nm or more and 300 nm or less. 68. Si disposed on the side opposite to the recording film
67. The information recording medium according to claim 62, further comprising a first protective layer made of O ₂ and a _second protective layer made of ZnS—SiO ₂ arranged on the recording film side. 69. A method of using an information recording medium comprising the information recording thin film according to any one of claims 35 to 55 as a recording layer, wherein the information recording medium is repeatedly irradiated with laser light during use. And a step of depositing the high melting point component in the information recording thin film of the information recording medium. 70. The information recording / reproducing apparatus irradiates the laser beam onto the information recording medium.
How to use the information recording medium described in. 71. A method of using an information recording medium according to claim 69, wherein the irradiation of the laser beam onto the information recording medium is performed in an initialization device for the information recording medium. 72. The information recording thin film according to claim 1, wherein the information recording thin film is irradiated with laser light. A high-melting-point component having a melting point relatively higher than that of the residual component is deposited, and the deposit contains the element X and is distributed in a region of the residual component of the information-recording thin film.