JP2585520C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION   [Industrial applications]   The present invention uses a recording beam such as a laser beam or an electron beam to produce, for example, video or audio.
Which analog signal is FM-modulated, for example, computer data,
Digital information such as x-similar signals and digital audio signals can be
Thin film for recording information that can be recorded by a system, especially related to phase change recording media
It is.   [Conventional technology]   There are various recording principles for recording on a thin film by laser light, but the phase transition of the film material
(Also called phase change), recording by atomic arrangement change such as photodarkening
, Two-sided discs are directly bonded to each other, as the film is hardly deformed
It has the advantage of being able to create discs. Also, if you select the composition appropriately,
Replacements can also be made. Many inventions related to this type of record have been filed
The earliest is disclosed in Japanese Patent Publication No. 47-26897. here,
Many thin films such as Te-Ge, As-Te-Ge, and Te-O were described.
Have been. Also, Japanese Patent Application Laid-Open No. 54-41902 discloses Ge.₂₀Tl_FiveSb_FiveSe₇₀,
Ge₂₀Bi_TenSe₇₀Various compositions are described. Also, Japanese Patent Application Laid-Open No. 57-24
039, Sb_{twenty five}Te_12.5, Se_62.5, Cd₁₄Te₁₄Se₇₂, Bi_TwoSe_Three, Sb_Two
Se_Three, In₂₀Te₂₀Se₆₀, Bi_{twenty five}Te_12.5Se_62.5, Cuse, and Te₃₃S
e₆₇Are described.   [Problems to be solved by the invention]   All of the thin films shown in the above prior art are writable or rewritable once
Crystallization speed is slow when used as a functional phase change recording film, and absorption of semiconductor laser light.
Poor sensitivity, poor reproduction signal strength, or stable amorphous state
It has drawbacks such as poor resistance and insufficient oxidation resistance, and is difficult to put into practical use.   Therefore, an object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to provide a recording / reproducing characteristic.
To provide a phase change recording medium for information recording with good sensitivity, high sensitivity, and good stability.
Yes.   [Means for solving the problem]   In order to solve the above problems, the phase change recording medium of the present invention has the following features.
You. (1) A substrate and at least one of an inorganic substance and an organic substance directly or on the substrate.
Irradiation of the recording beam formed through the protective layer made of
Phase-change recording medium having thin film for information recording that causes atomic arrangement change without any change
In, from at least one of inorganic and organic substances on the information recording thin film
And a reflective layer provided with an intermediate layer between the two layers.
Is represented by the general formula: CzGeαTeβ (where z, α, and β are atomic In cents, 5 ≦ z ≦ 65, 40 <z + α ≦ 65,10 ≦ α, 35 ≦ β <
55, Z + α + β = 100Values in the rangeC is Sb)
And (2) Further, the thickness of the intermediate layer is 3 nm or more and 400 nm or less. (3) Is the intermediate layer at least one of oxide, sulfide, nitride, and fluoride?
It is characterized by comprising. (4) Further, the thickness of the information recording thin film is preferably 15 nm or more and 50 nm or less.
Sign. (5) Furthermore, the order of lamination of each layer is such that the protective layer, the recording film, the intermediate layer, and the reflective layer are arranged from the substrate side.
It is characterized by the following.   The process of selecting the configuration of the present invention will be described below. Thickness of thin film for information recording
The average composition in the direction is represented by the general formula AxByCzGeαTeβ.   Here, x, y, and z are atomic percentages, respectively, 0 ≦ x <40, 0y ≦ 30,
0 ≦ z ≦ 65, 0 ≦ α ≦ 65, 10 <z + α ≦ 65, 35 ≦ β <60
And C is Sb, Sn, As, Pb, Bi, Zn, Cd, Si, Al, Ga and
And at least one element of In and has an effect of enhancing the stability of the amorphous state.
Have. B represents a halogen atom such as Tl or I and an alkali metal element such as Na
At least one of them. These elements form chains of Te in materials containing Te.
It has the effect of cutting the atomic arrangement and increasing the crystallization rate. However, the crystallization temperature
Unless it is added to a material having a high crystallization temperature, the stability of the amorphous state is impaired.
It will be. A is an element other than the elements represented by Te, Ge and C, and B
For example, Cu, Ag, Au, Sc, Y, Ti, Zr, V, Nb, Cr, Mo,
Mn, Fe, Ru, Co, Rh, Ni, Pd, Hf, Ta, W, Ir, Pt, H
g, B, C, N, P, O, S, Se, lanthanide element, actinide element, alka
It is at least one element of a lithium earth metal element, an inert gas element and the like. However
Ge, Te and one or more of the elements represented by B and C
If another element of each group is already used, it can be considered as an element of group A.
For example, As contained in the Tl-Sb-Ge-Te system at less than 40 atomic%
Added in a range where the sum of the content and the Sb content is 70 atom% or less, which is the upper limit of the content of group C elements.
Place to do It is possible. Of these, Hg, alkaline earth metal elements and inert gas elements are
It is preferable that the content be less than 10 atomic%.   The recording thin film of the present invention has a film thickness as long as the average composition in the thickness direction is within the range of the above (1).
The composition may change in the thickness direction. However, the change in composition should not be discontinuous
Is more preferable. By the way, among the elements represented by A, fiber metal elements such as Co
It facilitates the absorption of long-wavelength light such as conductor laser light to increase recording sensitivity, and
It has the effect of increasing the temperature, that is, the effect of increasing the stability of the amorphous state.
A compound with a high melting point or a high melting point of 600 ° C. or higher,
Therefore, high-speed crystallization is possible because it does not melt even at high temperatures during crystallization.
You.   The information recording thin film of the present invention having the composition range of the above (1) has excellent recording / reproducing characteristics.
And the power of the laser beam used for recording and erasing may be low. Also stable
The nature is also excellent.   The preferred ranges for x, y, z, α and β are as follows:
You. (A) 0 ≦ x <20, 0 ≦ y ≦ 10, 0 ≦ z ≦ 20, 0.85 ≦ α / β <1 and (B) 0 ≦ x <20, 0 ≦ y ≦ 10, 0 ≦ Z ≦ 20, 1 <α / β ≦ 1.15 (C) 0 ≦ x <30, 0 ≦ y ≦ 25, 5 ≦ z ≦ 65, 40 <z + α ≦ 6.5, 3
5 ≦ β <55 and (D) 1 ≦ x <30, 0 ≦ y ≦ 25, 40 <z + α ≦ 60, 35 ≦ β <60 and (E) β / α ≠ 1, 1 ≦ x <20, 1 ≦ y ≦ 10, 40 <z + α ≦ 60, 35 ≦
The range of β ≦ 85 is more preferable.   Further, x = y = z = 0 in (a) or (b), and x = y =
0, (d) and (e), 40 <α ≦ 60, (d) and (e)
0.85 ≦ α / β <1 or 1 <α / β ≦ 1.15, and (d) and (e)
And 5 ≦ z ≦ 20, and 2 ≦ 7 ≦ 10 in (e).
so is there.   The present invention particularly applies the above condition (c) to the general formula of AxByCzGeαTeβ.
And a phase change recording medium in which x = y = 0. here
, C elementSb. The atomic ratio of the contents of Sb and Te is preferably in the range of 1: 0.4 to 1: 1.4.   At least one surface of the recording film of the present invention is tightly protected by another substance.
Is preferred. More preferably, both sides are protected. These protective layers are
Acrylic resin plate, polycarbonate plate, epoxy resin plate, etc., or
For example, acrylic resin, epoxy resin, polyimide, polyamide, polystyrene
May be formed from organic substances such as nitrogen, polyethylene, etc.
Based on sulfide, sulfide, carbide, boride, boron, carbon or metal
It may be formed from an inorganic material. Further, these composite materials may be used. For recording film
Preferably, at least one of the adjacent protective layers is inorganic. Glass,
Substrates containing quartz, sapphire, iron, or aluminum as a main component are also inorganic
It can work as a material protection layer. Of organic and inorganic substances, those that are in close contact with inorganic substances
It is preferable in terms of heat resistance. However, thickening the inorganic layer (except for the substrate)
It is easy to cause at least one of crack generation, transmittance reduction, and sensitivity reduction.
On the side of the inorganic layer opposite to the recording film, a thick organic layer is used to increase the mechanical strength.
It is preferable that the material layers adhere to each other. This organic layer may be a substrate. to this
Therefore, deformation is less likely to occur. Examples of organic substances include polystyrene and acrylic.
Lil resin, polycarbonate, epoxy resin, polyimide, polyamide, hot
Ethylene-vinyl acetate copolymer known as melt adhesive
An adhesive or the like is used. UV curable resin may be used. In the case of a protective layer made of an inorganic substance
May be formed as it is by electron beam evaporation, sputtering, etc.
Reactive sputtering and film formation of at least one element of metal, metalloid and semiconductor
After forming, react with at least one of oxygen, sulfur and nitrogen
And easy to manufacture. Examples of the inorganic protective layer include Ce, La, Si, In,
Al, Ge, Pb, Sn, Bi, Te, Ta, Sc, Y, Ti, Zr, V, Nb
, Cr, and W, oxides of at least one element selected from the group consisting of
n, At least one element selected from the group consisting of Ga, In, Sb, Ge, Sn, and Pb
Sulfide or selenide, fluoride such as Mg, Ce, Ca, Si, Al, Ta
, B and other nitrides, Ti and other borides, boron and other carbides, boron and carbon
For example, whose main component is CeO_Two, La2O_Three, SiO, SiO_Two
, In_TwoO_Three, Al_TwoO_Three, GeO, GeO_Two, PbO, SnO, SnO_Two, Bi_TwoO_Three
, TeO_Two, WO_Two, WO_Three, Ta_TwoO_Two, Sc_TwoO_Three, Y_TwoO_Three, TiO_Two, ZrO_Two,
CdS, ZnS, CdSe, ZnSe, In_TwoS_Three, In_TwoSe_Three, Sb_TwoS_Three, Sb
_TwoSe_Three, Ga_TwoS_Three, Ga_TwoSe_Three, MgF_Two, CeF_Two, CeF_Three, CaF_Two, GeS
, GeSe, GeSe_Two, SnS, SnSe, PbS, PBSe, Bi_TwoSe_Three,
Bi_TwoS_Two, TaN, Si_ThreeN_Four, AlN, Si, TiB_Two, B_FourOf C, B, C
It has a composition close to one.   Of these, nitrides do not have very high surface reflectivity, have stable films,
TaN, Si_ThreeN_FourAlternatively, a composition close to AlN is preferable. Oxidation
Y is the preferred product_TwoO_Three, Sc_TwoO_Three, CeO_Two, TiO_Two, ZrO_Two, In_TwoO_Three,
Al_TwoO_Three, SnO_TwoOr SiO_TwoThe composition is close to Hydrogen of Si or C
Is also preferable. When recording by phase transition, the entire surface of the recording
It is preferable to pre-crystallize it, but if an organic substance is used for the substrate,
Since the substrate cannot be raised, it must be crystallized by another method. So
In the case of, UV irradiation and heating, light irradiation from flash lamp, high power gas laser
Irradiating light from the laser or a combination of heating and laser light irradiation
Is preferred. In the case of irradiation with light from a gas laser, the light spot diameter (half width) is 5μ.
When the length is not less than m and not more than 5 mm, efficiency is good. Crystallization only occurs on the recording track
Alternatively, the space between tracks may be left amorphous. Crystallized into amorphous recording thin film
Therefore, it is of course possible to record.   Generally, when light is applied to a thin film, the reflected light is reflected from the surface of the thin film and the back of the thin film.
Interference due to superposition with reflected light from Read the signal by changing the reflectance
In this case, by providing a light reflection (absorption) layer close to the recording film, interference
The effect is increased and the read signal is increased. To increase the effect of interference
For this purpose, it is preferable to provide an intermediate layer between the recording film and the reflection (absorption) layer. The middle layer is Also has the effect of preventing mutual diffusion between the recording film and the reflective layer during recording / rewriting
. The intermediate layer is preferably made of a substance that does not absorb much light used for reading. Above
The thickness of the interlayer is not less than 3 nm and not more than 400 nm, and is in a recorded state or an erased state.
In this case, the film thickness is such that the reflectance of the recording member is close to the minimum value near the wavelength of the reading light.
Preferably. The reflective layer is located between the recording film and the substrate and on the opposite side.
It may be formed on either side. A particularly preferable thickness range of the intermediate layer is 5 nm or more and 40 nm or more.
The range is as follows. A protective layer made of the above-mentioned inorganic substance also on the side of the reflective layer opposite to the intermediate layer
Is preferably formed.   On the light incident side of the recording film, at least one of recording light, erasing light, and reading light is used.
Also, it is preferable to form an anti-reflection layer that reduces the reflectance of one of them. The anti-reflective layer
The protective layer of the recording film may be used, or a protective layer is formed between the antireflection layer and the recording film.
May be. The antireflection layer and the protective layer are a recording layer, a protective layer, an antireflection layer, and a substrate.
Or the coefficient of thermal expansion is preferably changed sequentially with the adhesive or gaseous contact.
When one of the protective layer and the anti-reflection layer is not formed, or when each is composed of two or more layers
Preferably, the coefficient of thermal expansion changes sequentially.   The recording film of the present invention is used as a protective film by co-evaporation or co-sputtering.
Dispersed in oxides, fluorides, nitrides, organics, etc. which are said to be usable
You may. Doing so adjusts the light absorption coefficient and increases the reproduction signal strength.
There is a yang that can be used. The mixing ratio indicates that oxygen, fluorine, nitrogen, and carbon occupy the entire film.
Is preferably 40% or less. By forming such a composite film,
Usually, the rate of crystallization is reduced and the sensitivity is reduced. However, mixing with organic matter
Sensitivity is improved by film formation.   The preferred range of the film thickness of each part is as follows. I. Recording film (A) In the case of a single-layer film (without a reflective film): 60 nm or more and 350 nm or less. 18
The range of 0 nm or more and 300 nm or less is particularly preferable in view of the reproduction signal intensity and the recording sensitivity.
New (B) In the case of a structure having two or more reflective layers: 15 nm or more and 50 nm or less. B. Inorganic protective layer: 5 nm or more and 200 nm or less. However, protect with the inorganic substrate itself. 0.1 to 20 mm. C. Organic protective film: 10 nm or more and 10 mm or less. D. Intermediate layer: 3 nm or more and 400 nm or less. E. Light reflection layer: 5 nm or more and 300 nm or less.   The method of forming each of the above layers includes vacuum deposition, vapor deposition in gas, sputtering, and ion deposition.
Sputtering, ion beam evaporation, ion plating, electron beam evaporation
Any of coating, injection molding, casting, spin coating, plasma polymerization, etc.
Is appropriately selected.   The recording film of the present invention necessarily utilizes a change between an amorphous state and a crystalline state for recording.
There is no need to change the optical properties by any atomic change.   The recording member of the present invention can be used not only in a disk shape but also in a tape shape or a card shape.
Other forms can also be used.   The applicant has previously filed Japanese Patent Application Laid-Open No. 60-42095. This is As
, Sb, Bi, S, Si, Ge, Sn, Pb, Al, Ga, In, Ti, Zn,
Cd, Au, Ag, Cu, Ni, Pd, Rh, Cr, Mo, W, and Ta are 2 atomic%.
Not less than 40 atomic%, Te is not less than 30 atomic% and not more than 95 atomic%, and Se is not more than 3 atomic%.
The composition has a composition of 45 atomic% or less and O of 0 atomic% or more and 20 atomic% or less.   The applicant has previously filed Japanese Patent Application Laid-Open No. 61-86287. This is Te
This is a recording material having a quaternary composition, which essentially requires the following materials. Also, Japanese Patent Application Laid-Open No. 62-47839
Is a quaternary recording material containing Te and Se, and the composition range of Te is 30 atomic%.
It is as follows. As other prior applications, Japanese Patent Application Nos. 59-123001 to 123004 are disclosed.
is there. These are related to the improvement of oxide materials containing oxygen as an essential element.
You.   [Action]   The phase change recording medium of the present invention has a high crystallization speed, a high stability of an amorphous state,
High absorption of semiconductor laser light, high reproduction signal intensity, and good oxidation resistance. Obedience
Therefore, the recording / erasing characteristics are good, the sensitivity is high, and the stability of the recording state is good.   Ge-Te is replaced with C element (Sb) Is added in a predetermined amount to reduce the amorphous state.
(High crystallization temperature) to extend the retention life of recorded data. Can be. This is due to the addition of a trivalent to pentavalent covalent typical element.
It is considered that the amorphous network structure becomes strong. In addition, the crystallization activity
Due to the increase in energy, the stability of the amorphous state at room temperature is maintained.
Recrystallization by overwriting information (overwrite
G) becomes easier and the erasing characteristics become better..   〔Example〕   Hereinafter, the present invention will be described in detail with reference to Examples. (Example 1)   First, taking a Tl-Ge-Te-based recording film as an example, the general formula of AxByCzGeαTeβ
The characteristic according to the value of y is shown. AndWhen using a Tl-Ge-Te recording film as an example
A specific example of a method for producing a phase change recording medium and an evaluation method will be described. Manufacturing methods, records,
The evaluation method itself such as reproduction is a general method. As an embodiment of the present invention, a recording film
Is represented by the general formula described in the above condition (1), CzGeαTeβ (where z, α
, And β are in atomic percent, respectively, 5 ≦ z ≦ 65, 40 <z + α ≦ 65,
10 ≦ α, 35 ≦ β <55, Z + α + β = 100Values in the rangeC is Sb)
, And the manufacturing method and the evaluation method are as follows.
This may be the same as the case of the e-Te based recording film.   Ultraviolet rays on the surface of a disk-shaped chemically strengthened glass plate with a diameter of 13 cm and a thickness of 1.2 mm
A tracking groove replica that also serves as a protective layer is formed with the cured resin,
Is divided into 32 sectors, and at the beginning of each sector, a recess is formed in the groove between the grooves.
Track address and sector address etc. are inserted in the form of convex pits (this part is
First, it is reflected on the substrate 14 by magnetron sputtering.
Si having a thickness of about 100 nm, which is both a prevention layer and a protection layer._ThreeN_FourA layer was formed. Next, this board
Was placed in a vacuum evaporation apparatus having an internal structure as shown in FIG. In the deposition equipment
And four evaporation sources 1, 2, 3, and 4. Three of these are resistive
Thermal evaporation boats, one of which is an electron beam evaporation source. This
These boats and electron beam evaporation sources are used to record information on the substrate 14.
, Which is located on the circumference where the center is the same as the center axis 5 of the substrate rotation.
. Ge and Te were put into two evaporation boats, respectively, and used as an electron beam evaporation source.
T 1 was added. A mask with a fan slit between each boat and the board 6,
7,8,9WhenShutters 10, 11, 12, and 13 are arranged. Substrate 14
While rotating at 120 rpm, current is applied to each boat, and the electron beam is
The deposition material was deposited by applying the pressure.   The amount of evaporation from each evaporation source was measured by a quartz oscillator type film thickness monitor 15, 16, 17, and 18.
The current was controlled so that the evaporation rate was constant.   As shown in FIG._ThreeN_FourTl on layer 20_FiveGe₄₅Te₅₀
Was deposited to a thickness of about 250 nm. Si_ThreeN_FourLayers are based on refractive index
Anti-reflection to semiconductor laser light by setting appropriate thickness because it is higher than plate
Also serves as a layer. This film thickness interferes with light reflected on the front and back surfaces of the recording film,
When the laser is in an amorphous state or a state with poor crystallinity,
The film thickness is such that the reflectivity becomes substantially minimum near the length. Then again magnetrons
Si by puttering_ThreeN_FourProtective layer 22 with a composition close to
did. Similarly, another Si substrate is mounted on another similar substrate 19 '._ThreeN_FourProtective layer with composition close to
20 ', Tl_FiveGe₄₅Te₅₀Recording film 21 'of composition_TwoProtective layer with composition close to
22 'was deposited. The respective films of the two substrates 19 and 19 'thus obtained
UV curable resin protective layers 23, 23 'are applied and formed to a thickness of about 50 μm on the deposited film.
After that, the organic adhesive layer is formed with both of the ultraviolet-curable resin layers 23 and 23 'on the inside.
24 to produce a disk.   After heating the disc prepared above at 150 ° C. for about 1 hour,
Rotate and move in the radial direction to achieve an aperture ratio (Numeral Aparture) of 0.
Irradiation with argon ion laser light (wavelength 488 nm) focused by the lens 05
The recording films 21, 21 'were sufficiently crystallized. Recording was performed as follows. Day
The disk is rotated at 1200 rpm to record light from a semiconductor laser (wavelength 820 nm).
Is maintained at a level where no
By irradiating one of the recording films and detecting the reflected light, the tracking groove and
The center of the light spot always coincides with the middle of the grooveDoThe head was driven as follows. do this
Thus, the influence of noise generated from the groove can be avoided. Like this
Automatic focusing while racking so that more focus is on the recording film To increase the laser power according to the information signal, or to return to the original level.
The recording was performed by If necessary, jump to another groove
Recorded. It is thought that the recording film was changed to amorphous by the above recording.
Reflectivity change. In this recording film, the recording light spot with reduced power,
Alternatively, the length in the track direction is longer than the recording light spot and
The spread in the direction is recorded by irradiating the same laser beam as the recording light spot.
Can also be deleted. The distance between the nearest pits of the pit representing the address is
Assuming that the length of the erasing light spot in the track direction is 以上 or more and twice or less,
The address of the track or sector can be read by the erasing light spot. address
The length of the pit to be displayed is also １ ／ or more of the length of the erasing light spot in the track direction.
Preferably. The same applies to other pits provided in the header section. Record
Elimination is 3 × 10^FiveIt could be repeated more than once. Si formed above and below the recording film_ThreeN_Four
When the layer was omitted, a slight increase in noise occurred after several recording / erasing operations.   Reading was performed as follows. Rotate the disk at 1200 rpm and
Record and erase while tracking and autofocusing as you did during recording.
The intensity of the reflected light is detected with a low-power semiconductor laser beam that is not
I was born. In this embodiment, a signal output of about 100 mV was obtained. The recording film of this embodiment is
Excellent oxidation resistance, Si_ThreeN_FourNo protection film is formed at 60 ° C and relative humidity of 95.
%, Hardly oxidized.   In the above-mentioned Tl-Ge-Te recording film, the relative ratio between the Ge and Te contents.
If the Tl content is changed while keeping the rate constant, the crystallization temperature and
The irradiation time varied as follows.   In addition, the Tl content is also poor due to oxidation when a time passes before the protective film is applied.
Became significant when the content was 30 atomic% or more. Irradiation time required if y is too small
Has a disadvantage that the crystallization temperature is low when y is too large.
Have.   Here, part or all of Tl is substituted to form a halogen element or an alkali metal element.
Similar characteristics can be obtained by adding at least one of the elements. Halogen element F,
Among Cl, Br, and I, I is particularly preferable, whereas Cl, an alkali metal element,
Among LI, Na, K, Rb, and Cs, Na is particularly preferable, and K is more preferable.
No.   Next, the Tl content in the Tl-Ge-Te recording film was kept constant at 5 atomic%.
When the contents of Ge and Te are changed, the required irradiation time for erasing and the writing
The number of changeable times changed as follows.That is, the general formula AxByCzGeαTe
Characteristics of α and β among β were obtained.               If α is less than 10, the crystallization temperature is low.                             (Poor stability of amorphous state)               Difficult to record when α exceeds 65   When α and β are too large or too small
It has the disadvantage that the interval is long and the number of rewritable times is small. Where α = β
In the configuration, the number of rewritable times becomes extremely small.   Here, Sb, Sn, and the elements represented by C by substituting part or all of Ge are represented by C.
At least one of As, Pb, Bi, Zn, Cd, Si, Al, Ga and In
Similar properties can be obtained by adding one element. Of these, Sb is particularly preferred.
And then Sn, then As, In, Si, then Pb, Bi, Ga.
No. However, when Sn is added in a large amount, the crystallization temperature is significantly lowered. Sb
If the addition amount of any element is 5 atomic percent or more, there are effects such as improvement of recording sensitivity.
You. When the recording sensitivity is also considered, the ratio of the number of atoms of Sb or Bi to Te is particularly preferable.
Range is 1: 0.4 to 1: 1.6, and Sn and Si and Te are 1: 1.2 to 1.6.
1: 2.5, 1: 0.9 to 1.4 for As and Te, 1 for In and Te
: 0.5 to 1: 2.   As a method of evaluating a recording medium, for example, the power of laser light necessary for recording and the
There is a technique for measuring the raw signal strength. It is said that the power of laser light required for recording is high
It is possible to evaluate the drawbacks and the drawback that the reproduction signal strength becomes small.   The thickness of the recording film ranges from 80 nm to 150 nm and from 180 nm to 30 nm.
In the range of 0 nm or less, the reflectance change due to recording becomes large due to the effect of light interference.
,preferable. The recording sensitivity is high in the range from 180 nm to 300 nm. However
Recording and reproduction are possible in the range of 15 nm to 350 nm.   Si as protective film_ThreeN_FourInstead of SiO, SiO_Two, Y_TwoO_Three, CeO_Two, ZrO
_TwoSuch as oxides, nitrides such as TaN and AlN, Sb_TwoS_ThreeAnd sulfides such as ZnS
, CeF_ThreeOr amorphous Si, TiB_Two, B_FourClose to C, B, C, etc.
A composition may be used. (Example 2)   A 100 nm-thick Ge₄₈Te₅₂Form the recording film and figure
The disc indicated by No. 2 was created. In the Ge—Te recording film, Ge and Te are used.
The required erasing time and erasable number of erasures when the content of
changed.Here, the general formula of AxByCzGeαTeβ using only Ge and Te is used.
That is, characteristics by α and β were obtained.   When α and β are too large or too small
It has the disadvantage that the interval is long and the number of rewritable times is small. Where α = β
In the configuration, the number of rewritable times becomes extremely small.From the result of Example 1 and this result,
It can be seen that the value of y does not significantly affect the values of α and β. Therefore,Of this thin film
at least one of the elements represented by A less than 30 atomic% while maintaining the ratio of α to β
, At least one of the elements represented by B of 25 atomic% or less, 65 atomic%
Represented by the following CElementGood properties can be obtained by addition. Examples of the present invention and
Therefore, in the general formula of AxByCzGeαTeβ, A and B were added without adding A and B.
AsSbAnd 5 ≦ z ≦ 65, 40 in the composition of CzGeαTeβ
<Z + α ≦ 65,10 ≦ α,Atomic ratio of 35 ≦ β <55.   As a reference example, it is represented by CzTe having a thickness of 100 nm in the same manner as in Example 1. A recording film was formed.At this timeC is Sb, Sn, As, Pb, Bi, Zn, Cd
, Si, Al, Ga, and In. Contains multiple of these elements
It may be.   The effect of the element C is that Sb has a higher crystallization temperature among these.
Particularly preferred, then Sn, then As, In, Si, then Pb, Bi, Ga
Is preferred. When the recording sensitivity is also considered, the ratio of the number of atoms of Sb or Bi to Te is preferably high.
The preferred range is 1: 0.4 to 1: 1.4, and 1: 1 for Sn and Si and Te.
. 2-1: 2.5, As and Te 1: 0.9-1.4, In and Te
Is 1: 0.5 to 1: 2. (Example 3)   Next, a manufacturing method and an evaluation method of another embodiment will be described. Here, the recording film is Tl-Ge
In the embodiment of the present invention, the recording film material is Cz of the present invention.
There is no other change except for the GeαTeβ material.   As shown in FIG. 2, a polycarbonate substrate was formed by injection molding as a substrate.
Using a groove 25 for tracking on the surface, sputtering
A protective film 26 having a composition close to iO and having a thickness of 40 nm was formed. Next, Tl_TenG
e₄₇Te₄₃A recording film 27 having a composition of 30 nm and a thickness of 30 nm was formed. Then close to SiO
The intermediate layer 28 having a thickness of 20 nm is formed, and the Bi layer having a thickness of 60 nm is formed.₇Sb_Three
And a protective layer 30 having a composition close to SiO and having a thickness of 40 nm.
. Another substrate is prepared in the same manner, and the substrate is placed on the uppermost SiO layer 30 of both substrates.
After sputtering polyimide 31 to a thickness of about 0.5 μm,
The substrates are attached with the hot-melt adhesive 32 mixed with black pigment with the layer side inside.
A disc was produced in combination. A polyimide layer is also applied to the surface of the polycarbonate plate.
If it is formed by the sputtering method, a more stable disk can be obtained. Crystallization method, note
The recording method, the erasing method, and the reading method are almost the same as those in the first embodiment.   For the intermediate layer, instead of SiO, GeO described in Example 1 as being usable as a protective layer was used.
_Two, Al_TwoO_Three, CeO_Two, Y_TwoO_Three, SiO_Two, AlN, TaN and other inorganic transparent materials
The material may be used, or an organic layer may be used. This intermediate layer has a thickness of 3 to 40 n.
When m is set, mutual diffusion between the recording film and the reflective layer at the time of recording / rewriting is prevented, but optically, It is almost the same as not existing. Therefore, depending on the wavelength of the reflectance due to light interference
The change is close to the case of the two-layer structure of the recording film and the reflective layer.   If the reflective layer also undergoes a change in the atomic arrangement during recording, the reproduced signal becomes slightly larger.   Some or all of the B and C elements contained in the recording film are replaced with other elements in the same group.
It may be replaced with at least one of the elements. In addition, elements such as Co in Group A are used.
The addition of at least one of the elements below 30 percent in atomic percent
No support. However, it is preferable that the amount added is 20% or less in terms of the SN ratio.
No.   The recording film is in an amorphous state when the thickness of the recording film is in the range of 15 nm or more and 50 nm or less.
The reflectance at the time is reduced by interference, and a large reproduced signal is obtained. The thickness of the reflective layer is
5 nm or more and 300 nm or less, more preferably 40 nm or more and 200 nm or less
Is preferably within the range. By providing the reflective layer, the thickness of the recording film
As described above, a large reproduction signal can be obtained in a thinner area than in the case of a single layer.
Good characteristics can be obtained even in a composition region where the absorption coefficient is larger than that of a single layer.   When the film thickness of the recording film and the intermediate layer is changed, the minimum due to the interference of the read light reflectance
The wavelength that occurs changes. Minimal required anti-focus and tracking
Since the emissivity is 10 to 15%, if the minimum value of the reflectivity is less than this value, the readout is performed.
It is necessary to make the local minimum value on the long wavelength side or the short wavelength side from the wavelength of light.
Setting the minimum value on the short wavelength side can reduce the thickness of the recording film,
Prevent energy loss. However, when the minimum value comes to the long wavelength side,
Thicker, which is preferable in terms of the life of the recording film and the prevention of noise when rewriting data.
No.   As the material of the reflection layer, Bi, Bi instead of Bi-Sb is used._TwoTe_Three, Te, Sn
, Sb, Al, Au, Pb and many other semiconductors, semi-metals, metals and mixtures thereof
, Compounds can be used.   The recording film of this embodiment also has excellent oxidation resistance like the recording film of Embodiment 1, and
Even if there is a pinhole in the protective film, oxidation does not proceed around the pinhole.   〔The invention's effect〕   As described above, according to the present invention, the manufacturing process is simple, and the reproducibility is good.
, It is possible to obtain a phase change recording medium with good recording / reproducing characteristics and stable information for a long time.
Wear. Records can be rewritten many times.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing the structure of a recording member according to an embodiment of the present invention. FIG. 2 is a sectional view showing the structure of a recording member according to the embodiment of the present invention. FIG. 3 is a side view showing an internal structure of a vacuum evaporation apparatus used for producing a recording member of the present invention. Explanation of reference numerals 1, 2, 3 ... evaporation boat, 4 ... electron beam evaporation source, 6, 7, 8, 9 ... mask having a sectoral slit, 10, 11, 12, 13 ... shutter, 14 ... substrate, 15
, 16, 17, 18 ... Quartz crystal oscillator type film thickness monitor, 19, 19 '... Substrate, 20,
20 ', 22, 22' ... SiO ₂ layer, 21, 21 '... recording film, 23, 23' ... UV curable resin layer, 24 ... organic adhesive layer, 25, 25 '... substrate, 26, 26', 2
8, 28 ', 30, 30' ... SiO ₂ layer, 27, 27 '... recording film, 29, 29'
... Bi-Sb film, 31, 31 '... Polyimide resin layer, 32 ... Hot melt adhesive layer.

Claims (1)

[Claims] 1. Irradiation with a substrate and a recording beam formed directly on the substrate or via a protective layer made of at least one of an inorganic substance and an organic substance causes an atomic arrangement change with almost no deformation of the film. In a phase change recording medium having an information recording thin film capable of recording, erasing, and rewriting information, the information recording thin film is provided with an intermediate layer made of at least one of an inorganic substance and an organic substance on the information recording thin film. The information recording thin film has an average composition in the film thickness direction represented by a general formula: CzGe
αTeβ (where z, α, and β are each an atomic percent and 5 ≦ z ≦ 6
5, 40 <z + α ≦ 65, 10 ≦ α, 35 ≦ β <55 , z + α + β = 100 , and C is represented by Sb ). 2 . 2. The phase change recording medium according to claim 1, wherein the thickness of the intermediate phase is 3 nm or more and 400 nm or less. 3 . 2. The phase change recording medium according to claim 1, wherein said intermediate layer is made of at least one of an oxide, a sulfide, a nitride, and a fluoride. 4 . 2. The phase change recording medium according to claim 1, wherein said information recording thin film has a thickness of 15 nm or more and 50 nm or less. 5 . 2. The phase change recording medium according to claim 1, wherein the order of lamination of the layers is, from the substrate side, a protective layer, a recording film, an intermediate layer, and a reflective layer.