CN1155348A

CN1155348A - Optical information carrier

Info

Publication number: CN1155348A
Application number: CN95194588A
Authority: CN
Inventors: J·H·库姆斯; W·范艾斯-斯皮克曼; B·A·J·雅各斯; A·P·J·M·容杰内利
Original assignee: Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 1994-06-23
Filing date: 1995-06-12
Publication date: 1997-07-23

Abstract

A description is given of an optical information carrier comprising a substrate (1), a thin reflective layer (5), a dielectric layer (7), a phase-change recording layer on the basis of GeTeSe (9), a dielectric layer (11), an opaque metal reflective layer (13) and a protective layer (15). The information carrier can be inscribed, erased and read by means of a laser-light beam a and, in the inscribed state, complies with the CD-industrial standard. The recording layer (9) comprises an alloy having the composition GexTeySez, in atom %, wherein 47</=x</=53 17</=y</=41 12</=z</=30 and x+y+z>/=96 and, preferably, equal to 100.

Description

Optical information carrier

The present invention relates to utilize laser beam to write, read and delete the optical information carrier of information, described optical information carrier comprises a substrate of the accumulation of bearing many layers, and these layers are first reflection horizon, first dielectric layer successively, comprise recording layer, second dielectric layer and second reflection horizon of phase-change material of the alloy of germanium and tellurium.

The invention still further relates to the method for making this optical information carrier.

Known optical information carrier, for example CD (CD), compact disc read-only memory (CD-ROM) and videodisc (LV) all are to provide information by the fabricator, can only be utilized commercially availabie reproducing device to read by the user.Other optical information carrier can be write once by the user, for example CD-R (recordable).Can wipe and the user is rewritable and can be widely used by the information carrier that the standard CD phonograph is read.User oneself can write this information carrier to audio frequency, video or data message.Carried out after the erase step, just can write new information this information carrier.

Known a kind of reversible recording layer that rewritable optical information carrier has so-called phase-change material of wiping.By utilizing the described recording layer of focussed laser beam spot heating and then it being cooled off, just changed the crystalline state of this material, but and formed read bit in the position of laser spot.According to the difference of recording layer material, amorphous material changes and becomes crystalline material, or crystalline material changes over amorphous material.Also may occur from of the conversion of a kind of crystallization phase to another kind of crystallization phase.Recording layer for example is crystalline, has the performance that absorbs incident laser.

During writing information, with respect to according to the modulated focussed laser beam mobile message carrier of information to be written.Because sudden cold (quenching) just appearred in this moving in the phase change recording layers with crystallization/noncrystalline phase transformation, this sudden cold noncrystalline information bit that in the exposed region of recording layer, formed, the not exposed region of this recording layer keeps crystalloid.Crystalline material has the optical property different with amorphous material, so utilize low power focussed laser beam just can read the information that writes in the reflection as the light contrast.For some phase-change material, can become crystal region to amorphous regions again by heating, so just wiped the information that writes.Known this alloy is based on In_Se, In_Sb_Se, In_Sb_Te, Ge_Te, Se_Sb_Te, Ge_Sb_Te and Ge_Se_Sb_Te.Recording layer can be written into subsequently again.

Can write and the condition precedent of erasure information carrier is described information carrier and described CD-audio player compatibility but read at the standard CD phonograph, promptly discoid flat information carrier must meet the industrial standard of CD system, is called the CD industrial standard later on.This standard comprises CD-DA (DAB), CD-ROM, CD-i (alternately), CD-photo (photograph), CD-V (video) and CD-R (can write down).This just means especially that this information carrier is not written into the initial reflection coefficients R in (being actually crystallization) zone when using the information carrier of inversion of phases _HAll must have concrete minimum value with degree of modulation m.The vertical incidence substrate, wavelength is about under the situation of collimated laser beam of 785 nanometers R _HMust be 70% at least.When the information carrier that utilized focussed laser beam to read to be written into, modulated laser beam has been caused with respect to the difference of the reflection coefficient of crystallization recording layer in noncrystalline position, and this modulated laser beam is detected device subsequently and is for conversion into and meets the modulated photocurrent that writes numerical information that is encoded.Numerical information leniently is about 1 micron and produce in the long noncrystalline position between the 0.9 and 3.3 μ m of not coexisting according to drum speed.Modulated photocurrent is the HF signal, and its minimum fundamental frequency is 196KHz.The peak-to-peak value I of this photocurrent ₁₁Represent the peak value I of the HF signal of this 196KHz _{The peak}Represent.Degree of modulation m is defined as follows:

M=I ₁₁/ I _{The peak}(I) according to above-mentioned CD industrial standard, it must be at least 0.6.This modulated photocurrent is that the difference that is written into (noncrystalline) and is not written into reflection coefficient between (crystallization) zone by information carrier is caused.

In fact, find at R _HUnder the situation of 〉=70% information carrier, phase differential almost always is small enough to and can be left in the basket the contribution of modulation.This modulation mainly is that the difference by reflection coefficient is caused.In order to obtain required degree of modulation m=0.6, this information carrier must have minimum light contrast.Light contrast C is defined as follows:

C=100 (R _H-R _L)/R _H(II) in this formula, R _HHas aforesaid meaning, R _LIt is the reflection coefficient of the noncrystalline layer that is deposited.In fact, degree of modulation is less than the light contrast.This is considered to be caused especially by the big diameter of comparing with width noncrystalline position laser spot.The reflection coefficient of the noncrystalline position that is written in addition, is different with the reflection coefficient of the noncrystalline layer that is deposited.Noncrystalline position can also comprise a spot of crystalline material.Experiment shows: in order to satisfy the degree of modulation demand of m=0.6, necessary light contrast C must promptly be at least 80% greater than 60%.Because R _HMust be at least 70%, so R _LMust be less than 14%.

Except that above-mentioned optical demands, also wish to utilize very much same laser beam erasure information and write fresh information in information carrier simultaneously.This process is commonly called " directly rewriting ", and (DOW), its advantage is that independent erase step is unnecessary.Under the condition of the drum speed of the 1.2-1.4 meter per second of above-mentioned CD industrial standard regulation, the experiment that the applicant did shows: noncrystalline position (i.e. crystallization again) the required time te that wipes fully under the crystalline environment should be between 300 and 800 nanoseconds.This is considered to be exposed to by the noncrystalline position on rotation optical information dish, and short this fact of time of laser beam caused.Under such dish linear velocity because it is too short to be used for time of crystallization again, so if te greater than 800 nanoseconds, the perfect recrystallization of then noncrystalline position is impossible.If te less than 300 nanoseconds, just has during the writing of noncrystalline position, the local and temporary transient temperature that increases will cause the danger of crystallization more wholly or in part of institute's rheme, so, just in fact not form noncrystalline position or will have formed out of order noncrystalline position.

But it is difficult having found to make the requirement of satisfying above-mentioned CD industrial standard and the erasure information carrier that writes that can be properly used in DOW.

European patent application EP-the A-549024 (PHN 13.925) of applicant's application discloses and has started the sort of information carrier that section mentioned.This known inversion of phases information carrier comprises a substrate of the accumulation of bearing many layers, and these layers are recording layer, second dielectric layer and second reflection horizon of first reflection horizon, first dielectric layer, phase transformation GeTe alloy successively.The accumulation of this many layers can be described as the MIPIM structure, and M represents the reflection horizon, and I represents dielectric layer, and P represents phase change recording layers.This MIPIM structure has realized high initial reflection coefficients R _HWith sufficiently high contrast C, therefore described structure meets the CD industrial standard.Look up from substrate, this known information carrier for example comprises translucent thin Au reflection horizon, Ta ₂O ₅Dielectric layer, GeTe recording layer, Ta ₂O ₅Dielectric layer and lighttight Au layer.Interference effect has increased the initial reflection coefficient and the contrast of this information carrier.In this known rhythmo structure, the crystallizing layer that is deposited and the reflection coefficient of noncrystalline layer are respectively 70% and 12%.Light contrast C is 83%, so this information carrier meets the CD industrial standard.Except that GeTe, described patented claim has also been described the GeTe alloy that contains Sb and has been comprised the alloy of In, Sb, Se, Sn and/or Ga.But in this known information carrier that contains recording layer GeTe that meets the CD industrial standard aspect the optics such problem is arranged: promptly under the dish linear velocity at the 1.2-1.4 meter per second, described information carrier is not suitable for DOW.This is that the position that therefore writes is wiped free of again at once because the noncrystalline required time te in position in the perfect recrystallization GeTe had only for 50 nanoseconds.

The objective of the invention is to be provided at especially and meet writing and can wiping optical information carrier of CD industrial standard under the state of being written into, specifically, the initial reflection coefficient that satisfies RH 〉=70% requires and the degree of modulation requirement of m 〉=0.6, and this optical information carrier can also be suitable for being carried out " directly rewriting " under the linear velocity of the information carrier of 1.2-1.4 meter per second.In order to satisfy the requirement of degree of modulation m, light contrast C must be 80% at least.

The present invention also aims to provide the method for making this optical information carrier, in the method, can utilize laser beam that the complete amorphous recording layer crystallization (initialization) that is initially that is coupled with is become required recording layer.This back one requirement below will be described.

According to the present invention, the purpose that the optical information record medium that meets the CD industrial standard is provided is to utilize as start the optical information carrier described in the section to realize that this optical information carrier is characterised in that recording layer comprises that composition is the Ge of unit with the atomic percentage _xTe _ySe _zAlloy, wherein

47≤x≤53

17≤y≤41

12≤z≤30 and x+y+z 〉=96.

Optical property and/or erasing time are not being produced under the excessive adverse effect condition, in order to influence Tc, layer number of times (cyclicity) that can be wiped free of and can be written into and the life-span of recording layer, recording layer can comprise that at most atomic percentage is 4 O, Sb, N or Bi.For recording layer for simplicity, x+y+z=100 atomic percentage preferably.

Composition of the present invention can represent that the atomic percentage of Ge, Te and Se provides (see figure 1) along these leg-of-mutton three limits respectively with a zone in the triangle, and described zone is the parallelogram with following summit: Ge ₄₇Te ₄₁Se ₁₂(A) Ge ₄₇Te ₂₃Se ₃₀(B) Ge ₅₃Te ₁₇Se ₃₀(C) Ge ₅₃Te ₃₅Se ₁₂(D).

The experiment that the applicant did shows: if the composition of recording layer is outside these limits, degree of modulation m does not just meet the CD industrial standard, and/or erasing time te is just outside the scope of above-mentioned 300 to 800 nanoseconds, under given dish linear velocity, DOW is exactly impossible like this.Increase Se by the recording layer of giving Ge (Ge changes) and Te between 47 and 53 atomic percentage, can increase erasing time te and light contrast C.If Se content is 6 atomic percentages at least, DOW is exactly possible.But,, just must be limited in Se content between 12 and 30 atomic percentages if also plan to satisfy the degree of modulation demand.Under the Se of 12 atomic percentages, light contrast C and degree of modulation m become very little, and on the Se of 30 atomic percentages, they sharply increase.

Found only to allow the Ge content of recording layer to depart from 50 atomic percentages slightly, promptly maximum deviation is ± 3 atomic percentages.Outside these limits, contrast C and degree of modulation m just sharply reduce, and so, information carrier just no longer meets the CD industrial standard.In described limit, light contrast C is 80% at least, in addition, can also obtain to be at least 70% initial reflection coefficients R _H

X, y and z preferably have following value (is unit with the atomic percentage):

48≤x≤52

20≤y≤34

18≤z≤28。

This composition is positioned at the shade parallelogram (see figure 1) with following summit: Ge ₄₈Te ₃₄Se ₁₈Ge ₄₈Te ₂₄Se ₂₈Ge ₅₂Te ₂₀Se ₂₈Ge ₅₂Te ₃₀Se ₁₈

These stricter restrictions make the contrast C of information carrier bigger, so make the degree of modulation m of information carrier bigger.In described stricter limit, light contrast C is 86% at least, in addition, can also obtain to be at least 70% initial reflection coefficients R _H

Preferably use alloy Ge ₅₀Te _50-zSe _z, 12 atomic percentages≤z≤30 atomic percentages, preferably 18 atomic percentages≤z≤28 atomic percentages.Most suitable alloy with hard contrast C is Ge ₅₀Te ₂₅Se ₂₅

The reflection horizon M that is positioned at the MIPIM structure on substrate one side can be made of the metal or metal alloy of elements A u, Al, Cu and Ag.This reflection horizon M is translucent, for example has the transmission coefficient greater than 0.2.Reflection horizon M can also be by the dielectric layer that alternately has higher and lower transmissivity, for example be respectively Ta ₂O ₅And SiO ₂The dielectric mirror that constitutes of the accumulation of dielectric layer.

Be positioned at the preferably opaque metal level of reflection horizon M in the optical information carrier outside, this opaque metal level for example is made of the metal or metal alloy of elements A u, Al, Cu or Ag, so that this reflection horizon sees through laser as few as possible.Because Au is also corrosion-resistant to the optical maser wavelength high reflection of 785 nanometers, so the most handy Au makes this reflection horizon M.

By increasing dielectric layer I, can improve the reflection coefficient and the contrast of information carrier as interfering layer.In addition, described dielectric layer also makes recording layer P avoid possible oxidation and has prevented that metal from extending to recording layer P from reflection horizon M.Described dielectric layer has also guaranteed can controllably dispel the heat when noncrystalline position is write recording layer.

Can utilize common material, for example SiO ₂, TiO ₂, ZnS, AlN or Ta ₂O ₅Make dielectric layer.Can also alternatively use these mixtures of material, for example ZnS and SiO ₂Potpourri.Dielectric layer must be transparent to used optical maser wavelength.Can form reflection horizon and dielectric layer by vapour deposition or sputter.

Select the layer thickness of MIPIM structure so that C is maximum and make R _HAt least be 70%.

The substrate of information carrier is transparent to the optical maser wavelength of the 770-830 nanometer that is used to read at least, and for example uses polycarbonate, organic glass (PMMA), amorphous polyolefin or glass to make.Substrate must be transparent to the optical maser wavelength that is used to write and wipe also.According to the CD industrial standard, information carrier is a plate-like, and diameter is 120 millimeters, and the thickness of substrate is 1.2 millimeters.

Preferably having on the surface of the substrate of recording layer one side can be by the servo track that scans in the light mode.The normally spiral helicine groove of this servo track utilizes mould to form in substrate during injection molding or pressing mold.This groove can alternatively form in the synthetic resin layer of the UV of for example acrylate photocurable layers in reproduction process, and this synthetic resin layer provides in substrate separately.The spacing of this groove is 1.6 microns, and width is for example 0.6 micron.

For example can optionally utilizing, the protective seam of poly-(methyl) acrylate of UV photocuring makes the outermost layer of lamination not be subjected to the influence of environment.

Though GeTeSe alloy of the present invention is suitable for as the recording layer wiped in the information carrier that meets the CD industrial standard most, but described alloy also is suitable for using in other optical information carrier, for example non-plate-like, need the be big light contrast and the information carrier of degree of modulation.For this reason, can use flexible, for example banded substrate.

By carrying out vapor deposition with suitable target or sputter can be added to recording layer in the substrate.The layer that so adds is noncrystalline, presents low reflection coefficient.In order to form suitable recording layer with high reflectance, must at first make the crystallization fully of this layer, usually this is called initialization.For this purpose, can be heated to information carrier the Tc of relevant GeTeSe alloy in stove, this Tc is near 250 ℃.This method is not suitable for synthetic resin substrate, for example polycarbonate.On the other hand, can for example in pen recorder, utilize this noncrystalline layer of laser beam initialization with enough power, in this case, the information carrier of laser beam flying rotation.This noncrystalline layer is heated to Tc then partly, is not occurred by superheated rough sledding and do not have substrate.

But experiment has shown and can not utilize laser beam initialization in 10 microseconds to have the noncrystalline GeTeSe alloy of composition of the present invention that but can wipe on the other hand is the noncrystalline position of crystallization in 800 nanoseconds.This violent some strange phenomenon at a glance can be described as follows.The crystallization of amorphous material needs two independent processes, i.e. coring and growth.Coring is the process that forms little crystal grain in noncrystalline environment.Growth is the process that the volume of little crystal grain increases.The speed of these two processes all depends on temperature consumingly, but can be very inequality.The crystallization of single-phase noncrystalline layer needs coring and growth.But, for the noncrystalline position in the crystalline environment, because crystal grain can be along the edge of position to the growth of the center of position, so coring is unnecessary.So can very rapidly wipe (crystallization) noncrystalline position.Alloy of the present invention, for example Ge ₅₀Te ₃₂Se ₁₈And Ge ₅₀Te ₂₅Se ₂₅Have the noncrystalline position erasing time te of 350 and 600 nanoseconds respectively, therefore all be suitable for as CD-E (can wipe).The crystallization time of the single-phase noncrystalline layer of being made by these alloys is substantially greater than 25000 nanoseconds (＞25 microsecond), and utilizing the described alloy of laser beam crystallization is unusual difficulty.

Provide to make and aforesaidly be utilized the laser beam initialization and can in substrate, provide the purpose of method of the optical information carrier of dielectric layer I and reflection horizon M to be achieved in that in the present invention recording layer is made up of the noncrystalline layer of two stacks according to common mode, ground floor with ground floor thickness is the alloy that is mainly Ge and Te, the second layer with second layer thickness is the alloy that is mainly Ge and Se, selection component and layer thickness, so that after utilizing laser beam heats and mixing these two layers and cool off described layer, form crystallization recording layer Ge _xTe _ySe _z, x, y and z have above-mentioned value.

According to the present invention, recording layer is the phase change layer two stacks, inequality of GeTe and GeSe for example.Selection component and layer thickness are so that average assay is equivalent to required composition.One (GeTe) in described two layers have coring easily, then with regard to the characteristic of crystallization.Laser beam with enough power is mixed these two layers, cools off after this, has just formed a crystallizing layer of average assay.

Ge ₅₀Te ₂₅Se ₂₅Single-phase noncrystalline layer have greater than 1 millisecond (＞10 ⁶Nanosecond) nucleation time, therefore, although the erasing time of noncrystalline position was 600 nanoseconds only, it also is very difficult utilizing laser beam to carry out initialization.If the noncrystalline layer Ge by identical layer thickness is provided ₅₀Te ₅₀With noncrystalline layer Ge ₅₀Se ₅₀Two layers forming are then as heating Ge ₅₀Te ₅₀During layer, the very fast coring of described layer will make two layer crystallizations (initialization) and mix in 2 microseconds, form a crystallizing layer.Duan crystallization time can be initialised amorphous two layers in pen recorder like this.The composition of this crystallizing layer is Ge ₅₀Te ₂₅Se ₂₅, its characteristic is identical with the characteristic of the layer that is used as noncrystalline layer identical component that add, crystallization then.

Should be pointed out that European patent specification EP-B-217293 has described the reversible optical recording layer that is made of the TeGeSb alloy, Te can partly replace with Se.The experiment that the applicant did has shown that these alloys do not satisfy the requirement for CD-E.For example, alloy Ge ₃₉Te ₅₂Sb ₉The erasing time that 30 nanoseconds were only arranged is so these alloys are not suitable for " directly rewriting ".In addition, comprise that the light contrast C of the optical information carrier of this recording layer only reaches 74% in above-mentioned MIPIM structure, this is not enough for required degree of modulation.Under identical condition, composition is Ge ₃₉Te ₄₀Se ₁₂Sb ₉Alloy have the erasing time te of 550 nanoseconds, still, light contrast C and degree of modulation m have only 67% and 44% respectively.

Referring now to accompanying drawing, utilize one exemplary embodiment to describe the present invention in more detail, wherein

Fig. 1 represents with the atomic percentage to be the triangle component-part diagram of unit, and in the figure, composition range ABCD is a parallelogram, and hypographous is best region of the present invention,

Fig. 2 represents alloy Ge ₅₀Te _50-zSe _zBe the erasing time te of unit with the nanosecond, its is as being the function of the Se content z of unit with the atomic percentage,

Fig. 3 represents alloy Ge ₅₀Te _50-zSe _zR _HBe 70% information recording carrier be the light contrast C of unit with percentage, its is as being the function of the Se content z of unit with the atomic percentage, and

Fig. 4 is the schematic cross sectional views of optical information carrier of the present invention.

One exemplary embodiment 1

Fig. 2 represents alloy Ge ₅₀Te _50-zSe _zCrystallizing layer in the erasing time te (is unit with the nanosecond) of noncrystalline position and the relation between the Se content z (is unit with the atomic percentage).Target by the relevant composition of sputter carries out deposit to this crystallizing layer as a noncrystalline layer, then at this noncrystalline layer of stove intercrystalline to form a single-phase layer.This crystallizing layer is positioned at two dielectric layer Ta that thickness is 185 nanometers ₂O ₅Between.In these experiments, this crystallizing layer is stable with respect to laser beam, the center of the noncrystalline position of beam-pointing.Erasing time te is determined by the laser pulse duration of the required minimum in the noncrystalline position of complete crystallization.These experiments show: for the composition of the Se content z with at least 6 atomic percentage Se, erasing time te is in the OK range of from 300 to 800 nanoseconds, so these compositions are suitable for " directly rewriting " under the dish linear velocity of 1.2-1.4 meter per second.

Fig. 3 represents R _HIt is the light contrast (is unit with percentage according to formula II) of 70% information carrier and as the relation between the Se content z (is unit with the atom unit fraction) of the same alloy of recording layer.This relation shows: in the zone of te＞300 nanoseconds, 80% minimum contrast C requires the Se content z of at least 12 atomic percentages.On the Se of 25 atomic percentages, contrast C sharply reduces.On the Se of 30 atomic percentages, C is less than 81% for the light contrast.This means if atomic percentage 12＜z＜30 atomic percentages alloy Ge ₅₀Te _50-zSe _zJust be suitable for as CD-E.One exemplary embodiment 2

Fig. 4 schematically shows a part of section of optical information dish of the present invention.Label 1 expression diameter is that 120 millimeters and thickness are 1.2 millimeters glass plate-like substrate.One side of this substrate has the spiral servo track (not shown) of form of grooves.This groove utilizes reproduction process to form in the UV of acrylate photocurable layers.On this one deck of the acrylate that forms groove, add that thickness is the extremely thin Ta of 5 nanometers ₂O ₅Layer 3.Described layer 3 is as the adhesive linkage of the gold layer 5 that will be coupled with subsequently.On layer 3, provide the stacked of following structure: the Ta of the Au reflection horizon 5-20 nanometer of-15 nanometers ₂O ₅The Ge of dielectric layer 7-25 nanometer ₅₀Te ₂₅Se ₂₅The Ta of recording layer 9-27 nanometer ₂O ₅The Au reflection horizon 13 of dielectric layer 11 and-75 nanometers.

Described these layers can form by sputter or vapor deposition.After sputter, recording layer 9 is noncrystalline, utilizes Temperature Treatment that it is for conversion into crystallizing layer.Spraying paint of UV light curable acrylics is sprayed on the protective seam 15 that forms 10 micron thickness on the reflection horizon 13.

But the alloy of recording layer 9 is crystal counter-noncrystalline phase-change materials.Write, read and randomly the laser beam used of erasure information enter information carrier through the plane of incidence 17 of substrate 1.This light beam is schematically represented with arrow a.During writing, information carrier because peak power is the effect of the modulated laser beam of 60 milliwatts, has formed noncrystalline position with the constant linear velocity rotation of 1.2-1.4 meter per second in crystallization recording layer 9.Above-mentioned layer structure provided at room temperature and to be respectively 70.5% and 4.1% calculating reflection coefficient for crystallization and non-crystalline state (being deposited).Light contrast C then is 94%.The tested reflection coefficient of information carrier is respectively 71% and 10%, and degree of modulation m is 0.61 (formula I).Therefore, initial reflection coefficient and degree of modulation all meet the CD industrial standard, the information carrier that can reset in the standard CD phonograph and to be written into.

The erasing time of noncrystalline position was 600 nanoseconds, therefore can utilize the laser beam erasure information and can carry out " directly rewriting " under the dish linear velocity of 1.2-1.4 meter per second.The information carrier that promptly has been written into meets the CD industrial standard.One exemplary embodiment 3

The recording layer 9 that use has the heterogeneity of Ge, Te and Se comes repetition one exemplary embodiment 2.The information carrier that obtains is determined the erasing time te (is unit with the nanosecond) of noncrystalline position, and calculate crystallization and amorphous regions R respectively _HAnd R _LReflection coefficient.Utilize described data computation light contrast C (is unit with percentage) according to formula II.According to making reflection R H is the accumulation of 70% mode Optimization Layer.The results are shown in the following table.

Table

Numbering	Composition (atomic percentage)				????t _e(nanosecond)	????R _H???(％)	???R _L(％)	????C ??(％)
	Composition (atomic percentage)								????Ge	????Te	????Se	????Sb
	????1 ????2 ????3 ????4 ????5 ????6	????50 ????50 ????50 ????50 ????50 ????48	????38 ????35 ????32 ????29 ????25 ????27.8	????12 ????15 ????18 ????21 ????25 ????20.2					????Ge	????Te	????Se	????Sb	????- ????- ????- ????- ????- ????4	????350 ????400 ????350 ????650 ????600 ????300	????70 ????70 ????70 ????70 ????70 ????70	????12.4 ????11.9 ????9.6 ????6.1 ????3.7 ????10.8	????82 ????83 ????86 ????91 ????95 ????85
????7 ????8 ????9 ????10 ????11 ????12 ????13 ????14 ????15 ????16 ????17 ????18	????1 ????2 ????3 ????4 ????5 ????6	????50 ????50 ????50 ????50 ????50 ????48	????38 ????35 ????32 ????29 ????25 ????27.8	????12 ????15 ????18 ????21 ????25 ????20.2	????50 ????50 ????50 ????47.6 ????45.5 ????53.1 ????54.2 ????55.5 ????56.9 ????59.7 ????62.6 ????48	????44 ????15 ????50 ????42.9 ????36.4 ????35.8 ????29.4 ????22.2 ????32.7 ????25.8 ????18.7 ????36.5	????6 ????35 ????0 ????9.5 ????18.1 ????11.1 ????16.4 ????22.3 ????10.4 ????14.5 ????18.7 ????11.5	????- ????- ????- ????- ????- ????- ????- ????- ????- ????- ????- ????4	????300 ????- ????50 ????250 ????2000 ????650 ?????- ?????- ????1200 ?????- ?????- ????170	????70 ????70 ????70 ????70 ????70 ????70 ????70 ????70 ????70 ????70 ????70 ????70	????14.6 ????44.7 ????12.0 ????22.8 ????30.3 ????20.0 ????61.4 ????58.4 ?????- ????62.0 ????59.7 ????13.3	????79 ????36 ????83 ????67 ????57 ????71 ????12 ????17 ????- ????11 ????15 ????81	????- ????- ????- ????- ????- ????4	????350 ????400 ????350 ????650 ????600 ????300	????70 ????70 ????70 ????70 ????70 ????70	????12.4 ????11.9 ????9.6 ????6.1 ????3.7 ????10.8	????82 ????83 ????86 ????91 ????95 ????85

GeTeSe alloy 1-6 is the alloy that is suitable for as optical information carrier of the present invention.Alloy 1-5 is in the parallelogram ABCD of Fig. 1.Comprise that these alloys have at R as the information carrier of recording layer _HValue is that 70% o'clock minimum is 80% contrast C and the erasing time te between 300 and 800 nanoseconds.These alloys make the optical information carrier that meets the CD industrial standard can be manufactured.Experiment 3,4 and 5 is all in the shadow region of Fig. 1, and at R _HValue is to present very high contrast C under 70% the situation.The alloy of experiment 6 comprises 4 atomic percentage Sb ₁Erasing time with 300 nanoseconds is so it is just in time in institute's claimed range of 300-800 nanosecond.

Alloy 7-18 presents too low contrast C to have inappropriate erasing time te exactly, promptly outside the 300-800 nano-seconds.

Information carrier of the present invention is can write and can wipe optical information carrier, and under the state of being written into, it meets the CD industrial standard and is suitable for " directly rewriting ".

Claims

1. utilize laser beam to write, read optical information carrier with erasure information, described optical information carrier comprises a substrate of the accumulation of bearing many layers, these layers are first reflection horizon, first dielectric layer successively, comprise recording layer, second dielectric layer and second reflection horizon of phase-change material of the alloy of germanium and tellurium, it is characterized in that this recording layer comprises that composition is the Ge of unit with the atomic percentage _xTe _ySe _zAlloy, wherein

47≤x≤53

17≤y≤41

12≤z≤30 and x+y+z 〉=96.

2. the optical information carrier of claim 1 is characterized in that x+y+z=100.

3. the optical information carrier of claim 1 is characterized in that x, y and z have following value:

48≤x≤52

20≤y≤34

18≤z≤28。

4. the optical information carrier of claim 1, the composition that it is characterized in that recording layer is Ge ₅₀Te _50-zSe _z, 12≤z≤30.

5. the optical information carrier of claim 1 is characterized in that the reflection horizon comprises gold.

6. the optical information carrier of claim 1 is characterized in that substrate comprises the servo track of laser beam.

7. that be used as the recording layer that can wipe in the optical information carrier is the alloy Ge of unit with the atomic percentage _xTe _ySe _zApplication, wherein

47≤x≤53

17≤y≤41

12≤z≤30。And x+y+z 〉=96 preferably equal 100.

8. make the method for the described optical information carrier of claim 1, crystallization recording layer, dielectric layer and the reflection horizon that provides in substrate in common mode is provided this optical information carrier, it is characterized in that recording layer is made up of the noncrystalline layer of two stacks, ground floor with ground floor thickness is the alloy that is mainly Ge and Te, the second layer with second layer thickness is the alloy that is mainly Ge and Se, selection component and layer thickness, so that after utilizing laser beam heats and mixing these two layers and cool off described layer, form crystallization recording layer Ge _xTe _ySe _z, x, y and z have above-mentioned value.

9. the method for claim 8 is characterized in that two noncrystalline layers are become identical thickness by sputter, and ground floor uses alloy Ge ₅₀Te ₅₀, the second layer uses alloy Ge ₅₀Se ₅₀, forming composition thus is Ge ₅₀Te ₂₅Se ₂₅The crystallization recording layer.