JPH02151481A - Membrane for recording data and method for recording and reproducing data - Google Patents

Abstract

PURPOSE:To obtain a data recording membrane having good recording/ reproduction characteristics, high sensitivity and good stability by setting the average composition of the data recording membrane in the membrane thickness direction thereof to a composition represented by a specific formula. CONSTITUTION:The data recording membrane represented by the formula SbxTeyAzBalphaCbetaDgamma (wherein x, y, z, alpha, beta and gamma have values of 5<=x<=70, 10<=y<=85, 3<=z<=50, 0<=alpha<=20, 0<=beta<=30 and 0<=gamma<=30 in atomic %, A is at least one element selected from Sn, Bi, Pb, Ga, Au and In, B is at least one element selected from Tl,a halogen element and alkali metal, C is at least one element selected from Ag, Cu, Pd, Ta, W, Ir, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh and Ni and D is Sb, Te or an element other than the elements represented by A, B and D) formed to a substrate directly or through a protective layer is irradiated with recording beam to change the atom arrangement of the irradiated part. This membrane is irradiated with reproducing beam to read a change of atomic arrangement to record and reproduce data.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for recording data using a recording beam such as a laser beam or an electron beam.
For example, it relates to an information recording thin film that can record in real time FM modulated analog signals such as video and audio, computer data, facsimile signals, digital audio signals, and other digital information. be. [Conventional technology] There are various recording principles for recording on thin films using laser light, but recording based on atomic arrangement changes such as phase transition (also called phase change) of the film material and photodarkening does not involve almost any deformation of the film. Therefore, it has the advantage of being able to create a double-sided disc by directly pasting two discs together. Furthermore, if the composition is appropriately selected, it is also possible to rewrite records. Many inventions relating to this type of recording have been filed, the earliest being disclosed in Japanese Patent Publication No. 47-26897. Here, Te-Ge system, As-Te-Ge system, T
Many thin films such as e-0 series are described. Furthermore, Ge is also disclosed in Japanese Patent Application Laid-Open No. 54-41902. 'r Q
, 5bsS870 and other various compositions have been described. Also, in JP-A-57-24039, S bziT 8z
z*g S e62aS. Cd,4Tai4Se,,,B i,Se,,5b2S
e,,I n,,Te,. S esll, B i,,T
e,,,, S e,,,,. Thin films of Cu5e, and T e33S e, are described. [Problems to be Solved by the Invention] When used as a one-time writeable or rewritable phase change recording film, the above-mentioned conventional thin films have a slow crystallization speed, low absorption of semiconductor laser light, and poor sensitivity. However, it has drawbacks such as insufficient reproduction signal strength, large distortion of the reproduced waveform, poor stability of the amorphous state, insufficient oxidation resistance, and large residual amount, making it difficult to put it into practical use. be. Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a thin film for information recording that has good recording/reproducing characteristics, high sensitivity, and good stability. [Means for Solving the Problems 1] In order to achieve the above object, in the information recording thin film of the present invention, the average composition in the film thickness direction of the information recording thin film is expressed by the general formula SbxTeyAzBαCβDγ. . However, x, y, z, α, β, and γ are each expressed in atomic percent as 5≦x≦70.10≦y≦85゜3≦2≦50,
The values are in the range of 0≦α≦20, 0≦β≦30, 0≦γ≦30, and A is Sn and Bi. At least one element of Pb, Ga, Au and In,
B is at least one element selected from halogen elements such as Tl and I, and alkali metals such as Na. These elements have the effect of cutting the chain-like atomic arrangement of Te and Se in materials containing Te and Se and increasing the crystallization rate. However, since they are accompanied by a decrease in the crystallization temperature, If it is not added to high-quality materials, it will impair the stability of the amorphous state. C
are Ag, Cu, Pd, Ta, W, Ir, Sc, and Y. Ti, Zr, Vs Nb, Cr, Mo, Mn, Fe. At least one element among Ru, Co, Rh and Ni, D
is an element other than the elements represented by Sb, Te, Ay, B, and C, such as Hg, Se, S, and As. AQ, B, C, Si, No P, O, lanthanide elements,
At least one element selected from actinide elements, alkaline earth metal elements, inert gas elements, and the like. However, A,
One or more of the elements represented by B and C can also be considered as elements of group D if another element of each group is already used. For example, 5b-Te-3n-
Ni with respect to Co system, Ni content and C with less than 30 atomic %. It is conceivable that the elements are added in such a range that the sum of the contents is 30 atomic % or less, which is the upper limit of the content of group C elements. Among these, AQ
, Hg, alkaline earth metal elements, and inert gas elements are preferably contained in a content of less than 10 atomic %. The composition of the recording thin film of the present invention may vary in the thickness direction as long as the average composition in the thickness direction is within the above range. However, it is more preferable that the composition change is not discontinuous. Recording is performed with an energy beam of irradiation time and power that is capable of causing a change in atomic arrangement (for example, from one phase to another) and that does not cause significant deformation of the recording film. [Function] The roles of each of the above-mentioned group elements are as follows. By coexisting with elements such as Sn represented by Sb, Te, and B in an appropriate ratio, the amorphous state can be stably maintained and crystallization can be performed at high speed during recording and erasing. Make it. An element such as CO represented by C has the effect of increasing recording sensitivity by facilitating the absorption of long wavelength light such as semiconductor laser light, and also enables high-speed crystallization. The element represented by B, such as TQ, has the effect of improving the crystallization rate and also improving the stability of the amorphous state. If group B elements and group C elements coexist, high-speed crystallization is possible, the stability of the amorphous state is high, and the recording sensitivity is also high. When adding either the B group element or the C group element,
Addition of group B elements is preferable in terms of ease of film formation, but oxidation resistance decreases. Addition of an element such as Ar represented by D does not have a particularly significant effect, but if the amount added is small, there will be no major adverse effect. Note that among these elements, rare earth elements and the like can play roles such as increasing the reproduction signal intensity and increasing the crystallization temperature when added in an amount of 1 to 20%. In addition, Se and S have the effect of improving oxidation resistance by adding 1 to 20% while keeping the ratio of other elements constant. However, heat resistance is slightly reduced. Also in terms of erasing properties, the Se content is preferably 1 to 3%. The information recording thin film of the present invention having the above-mentioned composition range has excellent recording and reproducing properties, and requires low power of laser light used for recording and erasing. It also has excellent stability. X+ y+Z+ More preferable ranges of α, β and γ are as follows. The range is 10≦x≦45 35≦y≦80 5≦2・≦30 0≦α≦15 0≦β≦20 0≦γ≦20. Particularly preferred ranges of x, y, z, α, β and γ are as follows. 13≦x≦40 47≦y≦70 7≦2≦23 0≦α≦10 0≦β≦10 0≦γ≦10. However, if the element represented by A is Au,
If the Te content is low, the recording sensitivity is low, so 60≦y≦
A value of 70 is particularly preferred. In each of the above ranges, if the γ valve is O, the membrane can be easily produced. If 1≦α+β≦20, the amount of unerased data becomes smaller and the recording retention time becomes longer. If 1≦α≦10 and 1≦β≦10, the degree of signal modulation becomes even larger. Among the elements represented by B, TQ is particularly preferred. Next preferred are halogen elements, followed by other halogen elements such as CQ. Among the elements represented by D, rare earth elements are preferred. Among the elements represented by B, Pb, Ga, and In slightly lower the oxidation resistance. However, In is recorded/
Excellent erasing properties. Au reduces recording sensitivity but improves oxidation resistance. Although the change in the content of each element in the film thickness direction is usually small, there may be any pattern of change. Sb,
Regarding Se and S, near the interface of either one of the recording thin films (sometimes at the interface with another layer),
It is better to have more than inside. It is preferable that at least one surface of the recording film of the present invention is closely protected by another substance. It is even better if both sides are protected. These protective layers may be formed of organic materials such as acrylic resin, polycarbonate, polyolefin, epoxy resin, polyimide, polyamide, polystyrene, polyethylene, polyethylene terephthalate, fluororesin such as polytetrafluoroethylene (Teflon), etc. Often these may be substrates. Alternatively, it may be formed by an ultraviolet curing method. It may be formed from an inorganic material whose main component is oxide, fluoride, nitride, sulfide, selenide, carbide, boride, boron, carbon, or metal. Alternatively, a composite material of these may be used. Substrates based on glass, quartz, sapphire, iron, titanium, or aluminum can also serve as one inorganic protective layer. Among organic substances and inorganic substances, those in close contact with inorganic substances are preferable in terms of heat resistance. However, increasing the thickness of the inorganic layer (except for the substrate) tends to cause at least one of cracking, decreased transmittance, and decreased sensitivity. It is preferable that a thick organic layer be closely attached to the side to increase mechanical strength. This organic layer may be a substrate. This also makes deformation less likely to occur. Examples of organic substances include polystyrene, polytetrafluoroethylene (Teflon), polyimide, acrylic resin, polyolefin, polyethylene terephthalate, polycarbonate, and epoxy resin. Ethylene-vinyl acetate copolymer, which is known as a hot melt adhesive, and adhesives are used. It may also be an ultraviolet curing resin. In the case of a protective layer made of an inorganic material, it may be formed as is by electron beam evaporation, sputtering, etc., but it may be formed by reactive sputtering, metal,
Manufacturing is facilitated by forming a film made of at least one element of semimetals and semiconductors and then reacting it with at least one of oxygen, sulfur, and nitrogen. Examples of inorganic protective layers include Ce e La y S x p.
I n rAM, Ge, Pb, Sn, Bi, Te, T
an oxide of at least one element selected from the group consisting of a, Sc, Y, Ti, Zr, V, Nb, Cr and W; Cd;
Sulfide or selenide of at least one element selected from the group consisting of Zn, Ga, In, Sb, Ge, Sn, Pb, fluoride of Mg, Ce, Ca, Sx, AQ, T
It is made of nitrides such as a, B, boron, and carbon, and the main components are, for example, CeO2, La, ○, Sin,
5io2゜In203t Aff20. , Gem, Ce
O2, pb○. S no, 5no2. B i20. , TaO2, WO2
゜W○,,Ta2O,,Sc,O,,Y,○,,Tie
2゜ZrO,, CdS, ZnS, CdSe, Zn5e. I n2 S3# I n2 S e3t S J S
xp S bz S e3*Ga, Sl, Ga2Se,
, MgF, , CeF. CaF, , GeS, GeSe, GeSe2. SnS. S n S,, S n S e, S n S e
2. PbS, PbSe, Bi, Se,,
Bi, S, TaN, Si, N4゜AQN, Si, Ti
These are those having a composition close to one of B, B4C, SiC, B, and C, and mixtures thereof. Among these, sulfides close to ZnS are preferred because they have an appropriate refractive index and a stable film. Nitride having a composition close to TaN, Si, N4, or AQN (aluminum nitride) is preferable because the surface reflectance is not very high and the film is stable and strong. Preferred oxides are Y, O, Sc, O, CeO. Tie,,ZrO,,Sin,Ta,○5tInzo3
*It has a composition close to AQ, O,, SnO2 or SiO. Amorphous Si containing hydrogen is also preferred. If the protective film is made of multiple layers, the protective effect will be further enhanced. For example, a film with a composition similar to SiC2 with a thickness of 100 to 500 nm is formed on the side far from the recording film, and a film with a thickness of 80 to 130 nm is formed on the side far from the recording film.
When a film having a composition similar to that of ZnS is formed on the side closer to the recording film, both recording/erasing characteristics and multiple rewriting characteristics are good. By forming the protective film as described above, it is possible to prevent an increase in noise due to deformation of the recording film during recording and rewriting. When recording by phase transition (change), it is preferable to crystallize the entire surface of the recording film in advance, but if the substrate is made of an organic substance, it is not possible to heat the substrate to a high temperature, so other methods are recommended. It is necessary to crystallize it. In that case, irradiation with laser light focused to a spot diameter of 2 μm or less, irradiation with ultraviolet rays and heating using a xenon lamp, mercury lamp, etc., irradiation with light from a flash lamp, irradiation with a large light spot from a high-power gas laser, or It is preferable to use a combination of heating and laser light irradiation. In the case of light irradiation from a gas laser, the light spot diameter (
(Half value cap) Efficiency is good if the thickness is 5 μm or more and 5 mm or less. Crystallization may occur only on recording tracks, and the space between tracks may remain amorphous. There is also a method of crystallizing only between recording tracks. On the other hand, for example, when a thin film containing Sn, Sb, and Te as main components is formed by rotary evaporation from a plurality of evaporation sources, Sn, Sb, and Te are often hardly bonded together immediately after evaporation. Furthermore, when formed by sputtering, the atomic arrangement becomes extremely disordered. In such a case, it is best to first irradiate the recording track with a laser beam of high power density to melt the film as the case may be. Furthermore, by irradiating a recording track with a laser beam of low power density to cause crystallization, it is easy to make the reflectance uniform over the circumference of the track. It is possible to record with a laser beam whose power is modulated between the power level that produces crystallization and the power level that produces a state close to amorphous, regardless of the state after initialization as shown in L. It is. Generally, when a thin film is irradiated with light, the reflected light becomes a superposition of the reflected light from the surface of the thin film and the reflected light from the back surface of the thin film, causing interference. When reading signals based on changes in reflectance, by providing a light reflecting (absorbing) layer close to the recording film, the interference effect can be increased and the readout signal can be increased. In order to further enhance the interference effect, it is preferable to provide an intermediate layer between the recording film and the reflective (absorbing) layer. The intermediate layer also has the effect of preventing mutual diffusion between the recording film and the reflective layer during recording and rewriting. However, depending on how the material of the intermediate layer is selected, for example, if the intermediate layer is made of selenide, at least some of the elements of the recording film may be diffused into the intermediate layer, or at least some of the elements of the intermediate layer may be diffused into the recording film or the reflective layer. At least a portion of the recording can also be performed by diffusing it inside. The thickness of the intermediate layer is preferably S nm or more and 600 nm or less, and is preferably such that the reflectance of the recording member approaches a minimum value near the wavelength of the readout light in the recording state or erasing state. The reflective layer may be formed either between the recording film and the substrate or on the opposite side. A particularly preferable thickness range of the intermediate layer is 60/N n when the refractive index of the intermediate layer is N.
m or more and 160/Nnm or less and 470/Nn
The range is from m to 570/N nm. It is preferable to form a protective layer made of the above-mentioned inorganic material also on the side opposite to the intermediate layer of the reflective layer. These three layers (intermediate layer, reflective layer, and protective layer) collectively form a stronger protective layer than a single protective layer. As the reflective layer, metals, semimetals and semiconductors can be used, including Au, Ag, Cu, Ni and Fe. AQ, Co, Cr, Tie Pd, Pt, W. A layer of Ta, Mo or an alloy of these, a composite layer of these and other substances such as oxides, etc. are preferable. The reflective layer is made of Au or other material with a thermal conductivity of 2, OW/cm-deg.
When using the above-mentioned material with high thermal conductivity as a generating component,
It also has the effect of increasing thermal conductivity and ensuring that even if a recording film that crystallizes at high speed is used, it becomes amorphous when irradiated with high-power laser light. In this case, the intermediate layer also has high thermal conductivity A Q, O,, A Q N, Si, N4. Z
Use a material with a composition close to nS, etc., or use a material with medium thermal conductivity (0.02W/cm-deg or more and 0.1W/cl-68g or less) such as Sin, to make the intermediate layer thinner. is particularly preferred. The recording film of the present invention can be produced by co-deposition, co-sputtering, etc. using oxides, fluorides,
It may also be in the form of a nitride, an organic substance, etc., or dispersed in carbon or carbide. By doing so, it may be possible to adjust the optical absorption coefficient and increase the reproduced signal strength. The mixing ratio is preferably such that oxygen, fluorine, nitrogen, and carbon account for 40% or less in the entire film. By forming such a composite film, the speed of crystallization generally decreases, and the sensitivity decreases. However, forming a composite film with an organic material improves sensitivity. The preferred range of film thickness for each portion is as follows. Recording film When a reflective layer is not used, a range of 15 nm or more and 500 nm or less and 25 nm or more and 300 nm or less is particularly preferable in terms of reproduction signal strength and green recording sensitivity. 2/ with reflective layer! In the case of the above structure, 15 nm or more and 150 nm or less Inorganic protective layer 5 nm or more and 500 nm or less However, when protecting with the inorganic substrate itself, 0.1 to 20 mm Organic protective layer 500 nm or more and 10 mm or less Intermediate/IF 3 nm or more and 600 nm or less Light Reflective layer: 5 nm or more and 300 nm or less Inorganic protective layer adjacent to the light reflective layer 50 nm or more and 500 nm or less The materials and film thicknesses of each layer other than the recording film as described above are not limited to the recording film of the present invention, but may include other phase change recording films, optical It is also effective for magnetic recording films, interdiffusion type recording films, etc. The method for forming each of the above layers may be selected from among vacuum evaporation, gas evaporation, sputtering, ion beam evaporation, ion blating, electron beam evaporation, injection molding, casting, spin coating, plasma polymerization, etc. be. Most preferably, the protective layer, the recording film, the intermediate layer, the reflective layer, and the protective layer adjacent to the reflective layer are all formed by sputtering. The recording film of the present invention does not necessarily need to utilize a change between an amorphous state and a crystalline state for recording, but it is sufficient to cause a change in optical properties by some kind of atomic arrangement change that hardly involves a change in the shape of the film. . For example, it may be a change in crystal grain size or crystal shape, or a change between a crystal and a metastable state (π, γ, etc.). Even when changing between an amorphous state and a crystalline state, the amorphous state is not completely amorphous, and crystalline portions may be mixed. In addition, some of the atoms constituting these layers may migrate (due to diffusion, chemical reaction, etc.) between the recording layer, the protective layer, and at least part of the intermediate layer, or due to migration. Both phase changes may be recorded. The recording member of the present invention can be used not only in the form of a disk but also in other forms such as a tape or a card. [Examples] The present invention will be explained in detail below using Examples. A replica of a tracking groove that also serves as a protective layer is formed on the surface of a disk-shaped chemically strengthened glass plate with a diameter of 13 cm and a thickness of 1.2 mm using an ultraviolet curing resin, and the circumference is divided into 32 sectors, and at the beginning of each sector. First, by magnetron sputtering, a protective layer with a thickness of approx. A 300 nm SiO2 layer 2 was formed. Since this S io,i has a small refractive index difference with the substrate, there may be some unevenness or variation in the film thickness. Next, this disk was transferred to a sputtering device that has multiple targets and is capable of sequentially forming laminated films with good film thickness uniformity and reproducibility, and ZnS was sputtered to a thickness of approximately 110 nm to form N3. . Next, on the Zn8 layer 3, S n14 *) S b, ,,'re
A recording film 4 having a composition of ste, was formed to a thickness of about 30 nm. Subsequently, a protective layer 5 of ZnS was formed to a thickness of about 50 nm in the same sputtering apparatus. Further, an Au reflective layer 6 was formed thereon to a thickness of about 50 nm in the same sputtering apparatus, and then a ZnS protective layer 7 was formed to a thickness of 150 nm. Similarly, on another similar board 1', S 1o2J
12', Zn8 layer 3' Is nL413s b2.
．． 6'r eS71, recording film 4', ZnS layer 5
'Au reflective layer 6' and ZnS layer 7' were successively formed. The two disks thus obtained were bonded together with the adhesive layer 8 with the N7 and 7' sides facing inside. At this time, if the entire surface was glued, the number of rewrites could be increased, and if no adhesive was applied to the recording area, the recording sensitivity would be slightly higher. Recording, playback, and erasing were performed on the disc manufactured as described above in the following manner. The disk is rotated at 180 rpm, and the light from the semiconductor laser (wavelength 830 nm) is kept at a level that does not allow recording.The lens in the recording head focuses the light and irradiates it through the substrate onto one recording film, and detects one reflected light. By doing this, the head was driven so that the center of the optical spot was always aligned between the tracking grooves. By setting the recording track between the grooves, the influence of noise generated from the grooves can be avoided. While tracking in this way, automatic focusing is performed so that the focus is on the recording film, and first, the recording film on the recording track is heated by continuously irradiating a laser beam with high power density. Each element was reacted and crystallized. The range of laser power suitable for amorphization is higher than the power for crystallization and lower than the power that causes strong deformation or formation of holes. The range of laser power suitable for crystallization is high enough to cause crystallization and low enough to cause amorphization. Recording on an optical disk drive (recording/reproducing device) was performed as follows. The disk is rotated at 180 rpm, and the light from the semiconductor laser (wavelength: 830 nm) is kept at a level (approximately imW') that does not allow recording, and the lens in the recording head focuses the light and irradiates it through the substrate onto one recording film. By detecting the reflected light, the head was driven so that the center of the light spot was always aligned between the tracking grooves. By doing this, the influence of noise generated from the groove can be avoided. While tracking in this way, automatic focusing is performed to bring the focus onto the recording film. In the recording section, recording was performed by changing the laser power between an intermediate power level of 1.1 mW and a high power level of 18 mW as shown in FIG. The power ratio between the high power level and the intermediate power level is 1
The range of : 0.4 to 1 : 0.8 is particularly preferable. In addition, other power levels may be set for short periods of time. The recorded portion that is close to amorphous is considered to be the recording point. Once you pass the recording area, reduce the laser power to 1
mW and continued tracking and autofocusing. Note that tracking and automatic focusing continue even during recording. In such a recording method, even if it is performed on a portion that has already been recorded, the previously recorded information is rewritten with newly recorded information. That is, overriding by the eastern circular light spot is possible. The ability to override in this way is a feature of the recording film material of the present invention, which will be described in the fifth embodiment. However, during the first 11 revolutions or multiple revolutions during recording/rewriting, continuous light with a power close to 18 mW, for example 1.6 mW, which is the higher power of the above laser power modulation, is irradiated and erased, and then the next 1
By irradiating and recording with a laser beam whose power is modulated according to the information signal between 11 mW and 18 mW by rotation, there is little remaining information written previously and a high carrier-to-noise ratio can be obtained. In this case, the power of the continuous light that is first irradiated is 0.8 to 1.0 when the above-mentioned high power level is 1.
Good rewriting was possible within the range of 1. This method is effective not only for the recording film of the present invention but also for other recording films. Recording and erasing could be repeated 10' times or more. When the ZnS layers formed above and below the recording film were omitted, a slight increase in noise occurred after several times of recording and erasing. Reading was performed as follows. disk to t800
rpm, and while tracking and automatic focusing are performed in the same way as during recording, the strength of the reflected light is detected using a low-power semiconductor laser beam that does not perform recording or erasing.
Replayed information. In this example, a signal output of about 100 mV was obtained. The recording film of this example had excellent oxidation resistance, and was hardly oxidized even when it was placed at 60°C and 95% relative humidity without forming a ZnS protective film. In the recording film, when the relative proportions of other elements were kept constant and the Te content was changed, the required irradiation time for erasing changed as follows. Required irradiation time for erasing Sn, 5bs2Te, 5.0μ5ecSn
,. 5bGoTe11. 1.0μ5ecS n21
．． 7s b, 3. ,'r +3S 0.5 it s
e cS nxt-7s bzs,yT m47 0
, 1 μs e cSntoSt)zoTevo
o, lμ5ecSns, tSbx3.3Te,,
0.5μ5ecSnsSb1oTess 1
．． Oμs ecSn4Sb, Te8s 5.0μ
sec When the relative proportions of other elements were kept constant and the sb content was varied, the required irradiation time for erasing changed as follows. Required irradiation time for erasing n1g*4s b,'r e7? +@5 a Op
S e Qn,, S b, Te, sl, 0 p s
e cnl, S b,. 're,, o, 5
μS e Cn17*4s l)t3T81g, 4
0, 1 pse cnlts t) 4BIT 8
41 0, 1 μs e cS n11S b4
5Te, 4 0.5 Ps e cSn, Sb. Te,, 1. Qμ5 ecS n5S b
75T m20 5- Op sec When the relative proportions of other elements are kept constant and the Sn content is changed, the power of the laser light required for recording and the irradiation time required for erasing change as follows. did. Recording laser power S niS b23T e,. Sn3 S b 32 e3 T e G4 m73
n, S b31@t're,,. Sn, Sb, Te. S n 23 S b 25 m7 T e st +
3S n30 S b,,,'r 8BBS n G
6 S b 1g, 7 T e 33 +3S ns
g S b,, T a,. 6mW 6mW 6mW 6mW 6mW 8mW 0mW Required irradiation time for erasing when recording is not possible 5n1SbxzTess 2. Oμ5ecS
n, s 1) 32+3Te64.7 1e Oμ”A
e QSn, Sb, tTeaz, 30.5μ5ec
S n, S b,, Te, □0.1 μs e cS
nz3S bzg*1Te51-3 0+ 1 μS
e QS n:lo S b23. ,”r e4'GH
70,5μ5ecS ns,,S bls-7T 83
3.30 , 5 μS e QSn, , Sb□, Te,
. Q, 5μ5ecSn-3b-Tea element homology diagram b, When the composition is changed on the straight line connecting Te and 5nTe, the required irradiation time for erasure and the crystallization temperature when the temperature is raised at a constant rate are as follows. It changed like this. Sn xz S bzz IIG T 1B 55 +
4S n,, Sbi, Te54 S n 43 a@S b 5 T e G1 ++
2Sn,,5b4Te,1 Crystallized part S l'l 2 S b 3@ e5 T e sg
+6S n3 S b a7 *6 T e gg +4
S n5 S b3sT esg S n 7 S b 34 n4 T e 5B +l
iS n23 S b, L,,'r ass. S n3. S bl, T e,. S n43-as bsT es□, zSn45Sb4
Te, engineering 1μs 1μs 1μs 1μS C C Q (3Q degree 220℃ 220℃ 200℃ 180'C 180℃ 160℃ 140℃ 120'C Required irradiation time for erasing S n2 S b3g, sT ass, s 2,
O/A SS nx S bsl, sT ass, 4
1, O/A SSSn5S))xsTe5
o, 5 μs S n7 S b34-4T e5B-s
0, 1 /! S C C C C When the TQ content was varied while keeping the relative proportions of other elements constant, the required irradiation time for erasing changed as follows. Required irradiation time for erasing a= 0 0.1μ5ec a= 1 0.05μ5eca=10
0.05 μsec α=15 0.05 μ5 ec If TQ is greater than the above content, the time until the transmittance increases by 20% at 60° C. and 95% is short. When the relative proportions of other elements were kept constant and the CO content was varied, the crystallization temperature and the power of the laser beam required for recording changed as follows when the temperature was raised at a constant rate. Crystallization β=0 β=1 β=10 β=20 β=30 β=35 Temperature 180°C 280°C 300°C 300°C 300°C 300°C Recording laser power β=0 16mW β”1 16mW β=10 16mW β= 20 18 mW β= 30 20 m W β=35 It is possible to increase the degree of signal modulation by simultaneously adding TO and Co while keeping the relative proportions of other elements constant, which cannot be recorded. The addition of 30% or less of a rare earth element such as Gd while keeping the relative proportion of the elements constant has the effect of increasing the crystallization temperature. 20% or less is preferable. 10% or less is particularly preferable. Represented by D Addition of other elements improves sensitivity slightly.
It has effects such as improving oxidation resistance. The thickness of the intermediate layer is 60 when the refractive index of the intermediate layer is N.
/N nm or more and L 60 /N nm or less is preferable in that the erasure ratio is large. The thinner the film thickness, the faster the cooling rate after laser irradiation, and the more amorphous formation can be ensured. However, recording and reproduction is possible even in the range of 3 nm or more and 600 nm or less. Bi, Pb by replacing part or all of Sn. Similar characteristics can be obtained by adding at least one element among Ga, Au, and In. this house. A u z 4 , 3 S b in which Sn is replaced with Au
2B, 6Te57,, when the Te content is changed while keeping the ratio of other elements constant,
The laser power required for recording changed to the following: Recording laser power y=47 20mW y=55 18mW y=60 16mW y"70 16mW If part or all of Sn is replaced with Bi and all Wj of ZnS is S b2S e, the adjacent layer of Bi As a result, high recording sensitivity and a sharp rise characteristic of the recording power vs. reproduction signal strength curve were obtained, but the characteristic changes due to repeated rewriting became large. Very similar characteristics can be obtained by adding at least one element among halogen elements and alkali metal elements.Among the halogen elements F, CI2, Br, and I, which are preferred next to TQ, ■ is particularly preferred, followed by CQ. Preferred. Among the alkali metal elements Li, Na, Rb, and Cs, Na is particularly preferred, followed by K. Part or all of Co is replaced with Cu, Ag+Sc, Y
, Zr, V, Nb, Cr, Mo, Mn. Very similar characteristics can be obtained by adding at least one element among Fe, Ru, Ti, Rh, Ta, W, copper, and Ni. Among these, Tj, V. At least one element among Cr, Mn, Zr, and N1 is preferable because it can be easily vapor-deposited. Z used in at least part of the protective film and intermediate layer
Sin□, S io, Y2O3 or TaN instead of nS
, oxides and nitrides such as Al2N, Si, N4, 5b2
Sulfides such as 83, 5nSe2, 5bSe. Selenide such as CeF, fluoride such as amorphous Si, TiB2. B4C, BC, etc., or materials having compositions close to each of all of the above materials may be used. These laminated films (two or more layers) are also effective in increasing the protection strength. For example, the thickness is 300n on the side far from the recording film.
m SiO□ layer, 110 nm thick Z layer on the side near the recording film
The two-layer structure with the nS layer has little change in characteristics due to rewriting. It was good. As a reflective layer, some or all of Au is replaced with Ag,
Cu, Ni, Fe, An, Co, Cr. Similar characteristics were obtained using Ti, Pd, Pt, We Ta, Mo, and the like. Instead of chemically strengthened glass with an ultraviolet curable resin layer formed on its surface, polycarbonate, polyolefin, epoxy, acrylic resin, etc., with projections and depressions such as tracking guides formed directly on the surface may be used as the substrate. Effects of the Invention 1 As explained above, according to the present invention, it is possible to obtain an information recording member that has good recording/reproducing characteristics and is stable for a long period of time. It is also possible to rewrite the record many times.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a recording member in an embodiment of the present invention, and FIG. 2 is a diagram showing an override recording laser waveform in an embodiment of the present invention. 1.1'...Substrate, 2,2'...SiO□ layer, 3.
3'-ZnS layer, 4.4'--recording film, 5.5'-Z
nS layer, 6.6'-Au reflective layer, 7.7'...ZnS
layer, 8. ...Organic adhesive layer.

Claims (1)

[Claims] 1. In a thin film for information recording that undergoes atomic arrangement changes when irradiated with a recording beam formed directly on a substrate or through a protective layer made of at least one of an inorganic substance and an organic substance, The above information recording thin film has an average composition in the thickness direction of the general formula SbxTeyAzBαaCβDγ (where x, y, z, α, β, and γ are atomic percent, respectively, 5≦x≦70, 10≦y≦85, 3≦ z≦50, 0≦
The value is in the range of α≦20, 0≦β≦30, 0≦γ≦30, A is at least one element among Sn, Bi, Pb, Ga, Au, and In, and B is Tl, a halogen element, and an alkali. At least one element of metal, C, is Ag, Cu
, Pd, Ta, W, Ir, Sc, Y, Ti, Zr, V,
At least one element among Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh and Ni, D is Sb, Te, A, B
, an element other than the element represented by C). 2. General formula S formed directly on the substrate or via a protective layer consisting of at least one of an inorganic substance and an organic substance
bxTeyAzBαCβDγ (where x, y, z, α
, β and γ are each 5≦x≦70 in atomic percent,
10≦y≦85, 3≦z≦50, 0≦α≦20, 0≦β
≦30, 0≦γ≦30, A is Sn, B
i, at least one element among Pb, Ga, Au and In, B is at least one element among Tl, a halogen element and an alkali metal, C is Ag, Cu, Pd, Ta, W,
Ir, Sc, Y, Ti, Zr, V, Nb, Cr, Mo,
A recording beam is applied to an information recording thin film represented by at least one element among Mn, Fe, Ru, Co, Rh, and Ni (D is an element other than Sb, Te, A, B, and C). 1. A method for recording and reproducing information, comprising the steps of: irradiating the thin film to change the atomic arrangement of the irradiated portion of the thin film; and irradiating the thin film with a reproducing beam and reading out the change in the atomic arrangement. 3. The method for recording and reproducing information according to claim 2, wherein the recording beam is a laser beam.