CN101328573B - Once-writing-in multi-reading optical recording medium, sputtering target - Google Patents
Once-writing-in multi-reading optical recording medium, sputtering target Download PDFInfo
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- CN101328573B CN101328573B CN2008101340359A CN200810134035A CN101328573B CN 101328573 B CN101328573 B CN 101328573B CN 2008101340359 A CN2008101340359 A CN 2008101340359A CN 200810134035 A CN200810134035 A CN 200810134035A CN 101328573 B CN101328573 B CN 101328573B
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Abstract
A write-once-read-many optical recording medium enabling excellent recording and reproducing properties at a wavelength of blue-laser wavelengths or shorter, i.e. 500nm or less, particularly at wavelengths of near 405nm and high density recording. To this end, a write-once-read-many optical recording medium of the invention comprises a recording layer using a material represented by BiOx (0< x < 1.5), in which a recorded mark comprises crystal of Bi and/or crystal of a Bi oxide. Another write-once-read-many optical recording medium comprises a recording layer which comprises Bi, oxygen, and M (M represents at least one element selected from Mg, Al, Cr, Mn, Co, Fe, Cu, Zn, Li, Si, Ge, Zr, Ti, Hf, Sn, Mo, V, Nb, Y, and Ta), in which a recorded mark comprises crystal of the elements contained in the recording layer and crystal of an oxide of the elements.
Description
The application is August 30, application number in 2005 the dividing an application for the application for a patent for invention of " optical record medium that write-once repeatedly reads and sputtering target thereof " that be 200580001454.X, denomination of invention for the applying date.
Technical field
The present invention relates to a kind of write-once and repeatedly read (write-once-read-many, WORM) optical record medium.More specifically, the present invention relates to a kind of Write-once-read-many optical recording medium, it can carry out high density recording especially under blue laser wavelengths.The invention still further relates to sputtering target, it can be used in the formation oxide skin, and this oxide skin is for constituting the layer of this Write-once-read-many optical recording medium.
Background technology
Relevant with the Write-once-read-many optical recording medium that can under blue or shorter optical maser wavelength, write down and reproduce, blue laser that can super high-density recording is developed rapidly, and has promoted the exploitation to the Write-once-read-many optical recording medium of blue laser wavelengths sensitivity.
In common Write-once-read-many optical recording medium, laser beam irradiation to the recording layer that comprises organic materials with typically because the decomposition of organic materials and degenerate and change specific refractory power, and thereby form record pit (pit).The optical constant and the decomposition behavior that are used in the organic materials in the recording layer play an important role to forming satisfied record pit.
For the recording layer that the optical record medium that is used for for the blue laser wavelengths sensitivity repeatedly reads in write-once, organic materials must have suitable optical property and decomposition behavior with respect to the light of blue laser wavelengths.More specifically, the wavelength set that writes down obtains higher modulated amplitude thus in the afterbody of the length-wavelength side of the main absorption band refringence to increase the reflectivity in the non-recorded part and to be caused by the decomposition of organic materials when fully increasing when laser radiation.This is because in the main absorption band of this organic materials suitable uptake factor of the wavelength acquisition of length-wavelength side afterbody and high specific refractory power.
Yet, also do not find the organic materials that has the optical property that is equal to common material with respect to the light of blue laser wavelengths.In order to make this organic materials with contiguous blueness-optical maser wavelength absorption band, molecular skeleton must reduce or conjugated system must shorten.Yet this causes the uptake factor of reduction and the specific refractory power of reduction.More specifically, have many uptake factors that have the organic materials of contiguous blueness-optical maser wavelength absorption band and may control them, yet they there is not sufficiently high specific refractory power and can not obtains higher modulated amplitude degree.
Like this,, studying the material that uses inorganic materials and organic materials at present for the material that has the light activated optical property of blue laser wavelengths, and the material that only uses inorganic materials.As the material that uses oxide compound, patent documentation 1 discloses the recording layer that comprises Bi, rare earth, Ga, Fe and O, and this invention has been described and can be formed garnet composition.Patent documentation 2 discloses the optical record medium that uses organic oxygen compound.
Yet these common technology do not have research should form the record mark of which kind of shape to form excellent record mark effectively and to obtain excellent performance.Certainly, the shape that these technology do not have to consider this record mark when using with blueness-wavelength light is to obtain higher modulated amplitude, and it proposes as a problem at this.
In addition, for the optical record medium that the write-once of using metal or semimetallic oxide compound as recording layer repeatedly reads, the TeOx-Pd recording layer with high reliability proposes in patent documentation 3 and 4.In patent documentation 3 and 4, the ratio of components of TeOx-Pd recording layer changes on the thickness direction of this layer to improve reliability such as storage stability.In addition, comprise that the recording layer of TeOx-Pd also is disclosed in non-patent literature 1 and 2, yet, they only have as improve reliability method about controlling the wherein description of degree of oxidation.
About the material (though it is similar to the present invention) that contains the bismuth oxide compound, they are open in following patent documentation respectively: patent documentation 5 discloses by formula A
x(M
mO
n)
y(Fe
2O
3)
zAmorphous and the ferromagnetic oxide compound of expression has wherein defined various oxide compound A, the ratio separately of various element M, and x, y and z; Open metal oxide of patent documentation 6 and manufacture method thereof, this metal oxide comprise 50% or more by formula (Bi
2O
3)
x(M
mO
n)
y(Fe
2O
3)
zThe amorphous phase of expression has wherein defined M
mO
nM and the ratio separately of n, the ratio separately of x, y and z; Patent documentation 7 openly has by formula (B
2O
3)
X(Bi
2O
3)
1-XThe amorphous compound of the composition of expression, the scope of composition x, and quenching method; And patent documentation 8 discloses to have and has consisted of (Bi
2O
3)
1-x(Fe
2O
3)
XBismuth-iron amorphous compound material, yet x is expressed as 0.90 〉=x＞0.
Yet, these technology relate separately to transmitance and ferromagnetic amorphous oxide material, and they typically are used for the photoelectromagnetism optical record medium, are used for functional device, photoelectromagnetism transmitter, transparent and electrically conductive film, piezoelectric film etc. by magnetic action control light.In addition, these technology that other company provides purpose basically are to relate to the patent of material and/or material manufacturing method, not about being applied to the description of Write-once-read-many optical recording medium.
On the other hand, as making optical record medium one of method of recording layer, sputtering method is arranged.Sputter has extensively been known as a kind of method that forms thin layer under gas phase and has been used to the thin layer that process industry is used in the art.In sputtering method, preparation has the target material as the same composition of the layer that be about to form, and typically, the argon gas ion that glow discharge produces and target material collide the constituting atom with the beating target material, and this atomic deposition form layers thus to the substrate.Oxide compound typically has high-melting-point, thereby is unsuitable for by formation such as method of evaporation, and common use wherein applies the height-frequency-Bo sputtering method of high frequency ripple.
Sputtering method has many effects in its manufacturing processed, and sputter also has advantage on quantum of output.Yet, when formation contains when layer of the mixing material of two or more elements, have the composition situation inequality of target with layer, therefore, must consider the composition of target.Further, there are the structure in many its middle levels and characteristic to depend on the formation of the compound that constitutes target and the situation that changes, therefore must consider this point.
As technology known in the art, for example, patent documentation 9 discloses the target that comprises the Bi oxide compound as the sputtering target that forms dielectric film.Yet patent documentation 9 is not mentioned the target that comprises Fe.Because when the component type changes, the relation between this composition and the formation target compound and the structure of layer and the relationship change between the composition.Therefore, target structure must change, and effect for the reference of the sputtering target that proposes among the present invention is not played in disclosed discovery in the patent documentation 9.
In addition, patent documentation 10 discloses by Bi
3Fe
5O
12The target of making that is used to make thin layer, however this invention is used to make the thin layer with so-called garnet structure, wherein obtains the magneto-optic effect of height, and should invention employing Bi be 3: 5 to 3.5: 4.5 to the ratio of Fe.Therefore it is different from the sputtering target that proposes among the present invention.
Patent documentation 9 Japanese Patent Application Publications (JP-A) No.11-92922
Non-patent literature 1Proceedings of The 14
ThSymposium on PCOS2002, the 23-28 page or leaf
Non-patent literature 2 Vol.28, Eijogaku Giho, 5-8 page or leaf
Summary of the invention
Therefore the object of the invention is to provide a kind of Write-once-read-many optical recording medium, and it can be at 500nm or more shows excellent record-reproduction performance and record and reproduction and high density recording under the wavelength of contiguous 405nm especially under the small wavelength.
Further, another purpose of the present invention provides a kind of sputtering target, and it can be used for making oxide skin, and this oxide skin is to constitute the layer of optical record medium and be applicable at random to form the layer with stable composition and rock steady structure, and its manufacture method is provided.
A first aspect of the present invention is a kind of Write-once-read-many optical recording medium, it comprises substrate, recording layer and reflecting layer, wherein this recording layer comprises the material by BiOx (0＜x＜1.5) expression, and wherein records the recording of information mark and comprise Bi crystal and/or Bi oxide crystal.
A second aspect of the present invention is the Write-once-read-many optical recording medium according to first aspect, and wherein this record mark comprises quaternary Bi.
A third aspect of the present invention is a Write-once-read-many optical recording medium, it comprises substrate, recording layer and reflecting layer, wherein this recording layer comprises that Bi, O and M are as constituting element, M represents to be selected from least a element of Mg, Al, Cr, Mn, Co, Fe, Cu, Zn, Li, Si, Ge, Zr, Ti, Hf, Sn, Mo, V, Nb, Y and Ta and wherein records the recording of information mark to comprise one or more crystal in the crystal of the oxide compound that is selected from the crystal that is contained in one or more elements in this recording layer and these one or more elements.
A fourth aspect of the present invention is the Write-once-read-many optical recording medium according to the third aspect, and wherein this record mark comprises quaternary Bi.
A fifth aspect of the present invention is the Write-once-read-many optical recording medium according to the third aspect, and wherein the total amount of element M is 1.25 or littler to the atom number ratio of bismuth.
A sixth aspect of the present invention is the Write-once-read-many optical recording medium according to the third aspect, wherein this Write-once-read-many optical recording medium has any one following laminate structure: wherein recording layer, top coating and reflecting layer are arranged in suprabasil laminate structure and wherein reflecting layer, top coating, recording layer and tectum are arranged sequentially in suprabasil laminate structure with this at least in this order at least.
A seventh aspect of the present invention is the Write-once-read-many optical recording medium according to the third aspect, and wherein this Write-once-read-many optical recording medium is selected from BiFeO with comprising
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more sputtering target manufacturing.
A eighth aspect of the present invention is a kind of Write-once-read-many optical recording medium, it comprises substrate, recording layer and reflecting layer, wherein this recording layer comprises that Bi, O and L are as constituting element, and this recording layer comprises that Bi oxide compound and L represent to be selected from least a element of B, P, Ga, As, Se, Tc, Pd, Ag, Sb, Te, W, Re, Os, Ir, Pt, Au, Hg, Tl, Po, At and Cd.
A ninth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, and wherein element L represents to be selected from least a element of B, P, Ga, Se, Pd, Ag, Sb, Te, W, Pt and Au.
A tenth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, and wherein the total amount of element L is 1.25 or littler to the atom number ratio of bismuth.
A eleventh aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, and wherein this Write-once-read-many optical recording medium further comprises the top coating and have wherein that recording layer, top coating and reflecting layer are arranged sequentially in suprabasil laminate structure with this.
A twelveth aspect of the present invention is that wherein this Write-once-read-many optical recording medium further comprises undercoat and have wherein that undercoat, recording layer, top coating and reflecting layer are arranged sequentially in suprabasil laminate structure with this according to the Write-once-read-many optical recording medium of the tenth one side.
A thirteenth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, and wherein this Write-once-read-many optical recording medium further comprises top coating and tectum and have wherein that reflecting layer, top coating, recording layer and tectum are arranged sequentially in suprabasil laminate structure with this.
A fourteenth aspect of the present invention is the Write-once-read-many optical recording medium according to the 13 aspect, and wherein this Write-once-read-many optical recording medium further comprises undercoat and have wherein that reflecting layer, top coating, recording layer, undercoat and tectum are arranged sequentially in suprabasil laminate structure with this.
A fifteenth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, wherein this Write-once-read-many optical recording medium further comprises arbitrary at least layer of undercoat and top coating, and arbitrary at least layer of undercoat and top coating comprises ZnS and/or SiO
2
A sixteenth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, wherein this Write-once-read-many optical recording medium further comprises undercoat and top coating, and arbitrary at least layer of undercoat and top coating comprises organic materials.
A seventeenth aspect of the present invention is the Write-once-read-many optical recording medium according to eight aspect, is that 680nm or littler laser beam are realized record and reproduction with wavelength wherein.
A eighteenth aspect of the present invention is a kind of sputtering target, and it comprises Bi, Fe and O.
A nineteenth aspect of the present invention is the sputtering target according to the tenth eight aspect, and wherein this sputtering target is made up of Bi, Fe and oxygen.
A twentieth aspect of the present invention is that wherein this sputtering target is used to form the recording layer that is used for optical record medium according to any sputtering target of the tenth eight aspect to the 19 aspects, wherein is used in laser beam under 550nm or the littler wavelength and writes down and reproduce.
The of the present invention the 20 on the one hand is that wherein this sputtering target comprises Bi oxide compound and Fe oxide compound, or comprises the composite oxides of Bi and Fe according to any sputtering target of the tenth eight aspect to the 20 aspects.
The 22 aspect of the present invention is that wherein this sputtering target comprises the composite oxides of Bi and Fe and further comprises one or more that are selected from Bi oxide compound and Fe oxide compound according to the sputtering target of the 20 one side.
The 23 aspect of the present invention is the sputtering target according to the tenth eight aspect, wherein this sputtering target comprises one or more of the composite oxides that are selected from Bi oxide compound, Fe oxide compound and Bi and Fe, and this oxide compound is the oxide compound with the oxygen in a small amount of comparing with stoichiometric composition.
The 24 aspect of the present invention is according to any sputtering target in the tenth eight aspect to the 23 aspects, and wherein this sputtering target comprises and is selected from BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more.
The 25 aspect of the present invention is that wherein this sputtering target comprises Bi according to any sputtering target in the tenth eight aspect to the 24 aspects
2O
3And/or Fe
2O
3
The 26 aspect of the present invention is that wherein this sputtering target does not comprise Bi according to any sputtering target in the tenth eight aspect to the 25 aspects
2Fe
4O
9
The 27 aspect of the present invention is that wherein the content of Co, Ca and Cr is less than the detectability of inductively coupled plasma emission spectrometric method (inductively coupled plasma emission spectrometry) according to any sputtering target in the tenth eight aspect to the 26 aspects.
The 20 eight aspect of the present invention is according to any sputtering target in the tenth eight aspect to the 27 aspects, and wherein the tamped density (packing density) that has of this sputtering target is 65%-96%.
The 29 aspect of the present invention is that wherein the atomic ratio of Bi and Fe satisfies the requirement of Bi/Fe 〉=0.8 according to any sputtering target in the tenth eight aspect to the 20 eight aspect.
The 30 aspect of the present invention is the sputtering target manufacture method, wherein calcines Bi
2O
3And Fe
2O
3Powder is to make according to any sputtering target in the tenth eight aspect to the 29 aspects.
Hentriaconta-of the present invention aspect is an optical record medium, and it comprises substrate, recording layer and reflecting layer, and wherein this recording layer is selected from BiFeO with comprising
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more sputtering target form.
Description of drawings
Fig. 1 is the figure that is illustrated near the radial distribution function(RDF) (radial distribution function) of O in non-recorded part and the recording section (oxygen) atom.
Fig. 2 is the figure that near the radial distribution function(RDF) O (oxygen) atom of the Bi oxide compound of calculate measuring according to FEFF is shown.
Fig. 3 is the figure that the measuring result of Embodiment B-26 is shown.
Fig. 4 is the figure that the X-ray diffraction pattern of sputtering target 1 is shown.
Fig. 5 is the figure that the record performance of the optical record medium of making by use sputtering target 1 is shown.
Fig. 6 is the figure that the X-ray diffraction pattern of sputtering target 2 is shown.
Fig. 7 is the figure that the record performance of the optical record medium of making by use sputtering target 2 is shown.
Fig. 8 is the figure that the X-ray diffraction pattern of sputtering target 3 is shown.
Fig. 9 is the figure that the X-ray diffraction pattern of sputtering target 4 is shown.
Figure 10 illustrates the figure that has the record performance of the optical record medium that the sputtering target of different B i/Fe ratio makes by use.
Figure 11 is the figure that the X-ray diffraction pattern of sputtering target 5 is shown.
Figure 12 is the figure that the X-ray diffraction pattern of sputtering target 7 is shown.
Embodiment
Hereinafter, will describe the present invention in detail.
In order to obtain under blueness-optical maser wavelength or shorter wavelength, carrying out the Write-once-read-many optical recording medium of excellent record, following (1)-(3) have been proposed as important problem:
(1) can form little record mark
(2) less interference between record mark
(3) high stability in record mark
When using blueness-laser, must be chosen to be at blueness-wavelength can be by its material that writes down excellently, and does not resemble the situation of wherein using laser under near-infrared wavelength that is used for CD and DVD and red wavelength.
Because the Bi oxide compound is absorbed in the light of blueness-wavelength easily, can expect excellent record.
First aspect according to Write-once-read-many optical recording medium of the present invention comprises substrate, recording layer and reflecting layer, wherein the material by BiOx (0＜x＜1.5) expression is used for recording layer and wherein records the recording of information mark comprising Bi crystal and/or Bi oxide crystal.In order to produce higher modulated amplitude, require the refringence between record mark and non-recorded part big.When by BiOx (0＜x＜1.5) thus the material of expression is used for recording layer when record mark forms Bi crystal and/or Bi oxide crystal, change of refractive becomes greatly, and can realize higher modulated amplitude.For example, when non-recorded part is an amorphous and record mark when comprising crystallising part, can obtain higher modulated amplitude.When non-recorded part comprises the Bi oxide compound, by formation Bi-metal simple-substance in record mark, and the precipitation of non-oxidized substance, refringence is bigger, and can obtain the high more modulated amplitude that gets.Used up to now by making the pars amorpha crystallization form the method for record mark, yet, in the present invention, when in oxide compound, writing down, by using following phenomenon can expect higher effect, wherein Ji Lu part becomes the material except that oxide compound and the partial crystallization of this record.Comprise that the crystalline record mark with two or more different crystal-structures can suppress crystal growth and expansion and can form little record mark, can suppress crystal growth because have the mixed crystal of different crystal structure separately.
The change of the recording layer that causes by record will be further described.
By the material of BiOx (0＜x＜1.5) expression is to be difficult to the metastable state that exists under standard state, yet this state can form recording layer by sputter and realize in optical record medium.When laser beam irradiation to recording layer under metastable state BiOx (0＜x＜1.5) during with the increase temperature, separate easily becomes Bi and Bi oxide compound, because BiOx attempts to be returned to more steady state.It is believed that some Bi oxide compounds separate the state that no longer becomes oxide compound and become Bi from oxygen this moment in this.Because more stable status is a crystal state, therefore form Bi crystal and Bi oxide crystal, thereby and record mark become state comprising Bi crystal and/or Bi oxide crystal.
One side according to Write-once-read-many optical recording medium of the present invention comprises substrate, recording layer, and reflecting layer, wherein recording layer comprises Bi, O, with M as constituting element, wherein M represents to be selected from Mg, Al, Cr, Mn, Co, Fe, Cu, Zn, Li, Si, Ge, Zr, Ti, Hf, Sn, Mo, V, Nb, Y, at least a element with Ta, and wherein record the recording of information mark and comprise one or more crystal, these one or more crystal are selected from the crystal of the oxide compound of the crystal that is contained in one or more elements in this recording layer and these one or more elements.Write-once-read-many optical recording medium comprise substrate, recording layer and reflecting layer on the other hand, wherein this recording layer comprises that Bi, O and L are as constituting element, and this recording layer comprises that Bi oxide compound and L represent to be selected from least a element of B, P, Ga, As, Se, Tc, Pd, Ag, Sb, Te, W, Re, Os, Ir, Pt, Au, Hg, Tl, Po, At and Cd.
Can comprise bismuth by any state, as bismuth metal, bismuth alloy, bismuth oxide compound, bismuth sulphide, bismuth nitride, bismuth fluorochemical, yet this recording layer preferably includes a kind of bismuth oxide compound.Because the recording layer that contains the bismuth oxide compound can reduce the thermal conductivity of recording layer, obtain height-sensitivity and lower jitter value (jitter value), and make that the imaginary part of refraction complex indexes (complex index) is littler, this recording layer has excellent transparency, and forms several record layers easily.
Preferably, consider and improve stability and thermal conductivity, bismuth exists with the state of oxidation in recording layer with one or more elements that are selected from Mg, Al, Cr, Mn, Co, Fe, Cu, Zn, Li, Si, Ge, Zr, Ti, Hf, Sn, Mo, V, Nb, Y, Ta, B, P, Ga, As, Se, Te, Pd, Ag, Sb, Te, W, Re, Os, Ir, Pt, Au, Hg, Tl, Po, At and Cd, yet they needn't complete oxidation.In other words, when recording layer of the present invention comprised three kinds of elements of bismuth, oxygen and a kind of element (as Mg), it can comprise the oxide compound of bismuth, bismuth oxide compound, element (as Mg) and this element (as Mg).
Be used for making the bismuth that is blended in recording layer or the method for bismuth metal and Bi oxide compound, promptly be used to form the example of the method for the recording layer that bismuth element wherein exists with different states, comprise following method (A)-(C).
(A) use bismuth-oxide target sputter recording layer
(B) use bismuth target and bismuth-oxide target sputter recording layer
(C) use bismuth target sputter recording layer to introduce oxygen simultaneously to recording layer or cosputtering method
When employing method (A), the bismuth complete oxidation in target, this method is used and is depended on the phenomenon that sputtering condition such as vacuum tightness and sputtering power oxygen may lack.
At first, this recording layer wherein is described below and comprises that Bi, M and oxygen are as the write-once that constitutes an element aspect of reading ﹠ recording medium repeatedly.The attention element M represents to be selected from least a element of Mg, Al, Cr, Mn, Co, Fe, Cu, Zn, Li, Si, Ge, Zr, Ti, Hf, Sn, Mo, V, Nb, Y and Ta.
The material that comprises Bi, M and oxygen by use is used for recording layer, can carry out record for the light under blueness-wavelength excellently.Aspect of Write-once-read-many optical recording medium of the present invention, wherein recording layer comprises M, by being formed on the record mark under the oxide crystal state that wherein mixes two or more types, refringence between record mark and non-recorded part is bigger, and can obtain higher modulated amplitude.Further, be present in the recording layer, can obtain bigger effect by making not only the crystal of each autoxidisable substance but also the crystal of element simple substance.Can suppress the crystalline growth because crystal by making different elements or the crystal that has the different crystal structure separately mix, the crystalline record mark that comprises two or more different elements and/or crystal-structure can limit crystal growth and expansion and make it possible to form little record mark.
Record mark preferably includes quaternary Bi.Typically, about the valence state of Bi, trivalent Bi is steady state, yet for obtaining higher modulated amplitude, uses quaternary Bi.Condition according to the oxygen that centers on the Bi atom can make the valence state of Bi become tetravalence.Because change physicals by the valence state that changes Bi, can obtain higher modulated amplitude.
Quaternary Bi examples of compounds comprises BiO
2Typically, having structure is Bi
2O
3The Bi-oxide compound be steady state.Yet, depending on condition, the Bi-oxide compound can be taked as BiO
2Structure.By making recording layer have the crystalline structure that does not use, can obtain higher modulated amplitude with being true to type.
Also now being described below on the one hand of Write-once-read-many optical recording medium of the present invention.In this Write-once-read-many optical recording medium, recording layer comprises that Bi, L, oxygen and Bi oxide compound are as constituting element.Notice that element L represents to be selected from least a element of B, P, Ga, As, Se, Tc, Pd, Ag, Sb, Te, W, Re, Os, Ir, Pt, Au, Hg, Tl, Po, At and Cd.This recording layer comprises that bismuth is as main component.As comprising Bi and O element as the recording layer that constitutes element with adding to, but designed element M.Yet, but about the also designed element L that studies show that of the basic property that can add the formation element that constitutes element to.Element L can be added to as component and comprise that bismuth is as main component and comprise that a reason of the recording layer of Bi oxide compound is in order to reduce thermal conductivity to help forming little record mark.Because thermal conductivity is the value that is attributable to the existence of photon scattering, when particle diameter and crystalline size reduce, as atomic time of a plurality of constituent materials with when the nucleidic mass difference of composed atom is big etc., thermal conductivity can reduce.Therefore,, element L comprises bismuth as main component and comprise in the recording layer of Bi oxide compound, may command thermal conductivity and improve the high density recording performance by being added as component.
Further, comprising bismuth as main component and further comprise in the recording layer of bismuth oxide compound, the crystallization of bismuth oxide compound and bismuth by recorded information, however can be by the size of element L control crystal and crystalline particle.Therefore, element L can controlling recording crystal in the part and crystalline particle size and improve record greatly and reproduce performance as shaking.This is to add element L another reason as component to recording layer.
Consider thermal conductivity, can be used as component and add requirement that the element L in the recording layer will bear to seldom, except the degree of difficulty of the stability of simple requirement such as raw material and manufacturing.Yet the present inventor finds the reliability of recording layer, i.e. reproduction stability and storage stability depend on selected element L basically and change, and have the requirement of being born by element L clearly for reliability.
That is, as to will adding the result of a large amount of detections of requirement of the element L of recording layer to as component, the present inventor finds following requirement (I) or (II) is effective:
(I) having Pauling electronegativity value (Pauling ' s electronegativity value) is 1,80 or bigger element.
(II) having Pauling electronegativity value is 1.65 or the standard enthalpy of formation Δ H of bigger and oxide compound
f 0For-1000 (kJ/mol) or bigger element, do not comprise transition metal.
Satisfied by using (I) or element L (II), the Write-once-read-many optical recording medium that can obtain to have excellent record and reproduction performance (as shake) and high reliability.
Hereinafter, will explain requirement (I) and (II) in detail.
Comprise that bismuth mainly is that carrying out or the change of the state of oxidation such as change of valence state etc. by oxidation cause as the main component that constitutes element and the reliability degradation that comprises the recording layer of bismuth oxide compound.The standard enthalpy of formation of Pauling electronegativity value and oxide compound " Δ H
f 0" be important really as the value of the physicals of element L, because the change of the carrying out of oxidation and the state of oxidation is easy to cause the degradation of reliability.In order fully to improve the reliability of optical record medium, at first, preferred select to have Pauling electronegativity value be 1.80 or bigger element as element L.This is because oxidation is unlikely carried out on the element with high Pauling electronegativity value, and in order to ensure satisfied reliability, have Pauling electronegativity value and be 1.80 or bigger element be effective.The standard enthalpy of formation of oxide compound " Δ H
f 0" can get any value, condition is that Pauling electronegativity value is 1.80 or bigger.
Have electronegativity and be 1.80 or the example of bigger element L comprise B, Si, P, Fe, Co, Ni, Cu, Ga, Ge, As, Se, Mo, Tc, Ru, Rh, Pd, Ag, Sn, Sb, Te, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Po and At.
To sketch electronegativity herein.
Electronegativity is that expression is present in the scale that atom in the molecule can attract the power of electronics.The mode of determining the electronegativity value comprises Pauling electronegativity, William Mulliken electronegativity (Mulliken ' s electronegativity) and Allred-Rochow electronegativity.Among the present invention, determine the appropriateness of element L by using the Pauling electronegativity.
The bound energy E (AB) that the Pauling electronegativity has defined molecule A and B is respectively E (AA) and E (BB) greater than molecule AA and molecule BB[] the mean value of bound energy, and the difference between it is at each atomic electronegativity (X
A, X
B) between difference square.That is, it is expressed from the next:
E(AB)-[E(AA)+E(BB)]/2＝96.48(X
A-X
B)
2 ....(1)
In the Pauling electronegativity, this equation comprises gain factor 96.48 (1eV=96.48kJmol
-1), because the electronegativity value uses ev to determine.
Because electronegativity depends on predetermined element and which kind of valence state to introduce molecule with and change, when determining electronegativity in the present invention, use to give a definition.
That is, as follows, this value defined is the Pauling electronegativity value of element when following each family's element adopts following valence state respectively:
Element in 1 family adopts unit price; Element in 2 families adopts divalence; Element in 3 families adopts trivalent; 4 families element in 10 families adopts divalence; Element in 11 families adopts unit price; Element in 12 families adopts divalence; Element in 13 families adopts trivalent; Element in 14 families adopts tetravalence; Element in 15 families adopts trivalent; Element in 16 families adopts divalence; Element in 17 families adopts unit price; Element in 18 families adopts zeroth order.
For above-mentioned mention have electronegativity 1.80 or bigger element separately, be B (2.04) in the Pauling electronegativity value separately of the present invention's definition, Si (1.90), P (2.19), Fe (1.83), Co (1.88), Ni (1.91), Cu (1.90), Ga (1.81), Ge (2.01), As (2.18), Se (2.55), Mo (2.16), Tc (1.90), Ru (2.20), Rh (2.28), Pd (2.20), Ag (1.93), Sn (1.96), Sb (2.05), Te (2.10), W (2.36), Re (1.90), Os (2.20), Ir (2.20), Pt (2.28), Au (2.54), Hg (2.00), Tl (2.04), Pb (2.33), Po (2.00), and At (2.20).
These elements can join recording layer as constituting element with two or more combination.
Further, even the present inventor finds that Pauling electronegativity value less than 1.80, has the standard enthalpy of formation Δ H of the oxide compound of Pauling electronegativity value 1.65 or bigger and this element
f 0For-1000 (kJ/mol) or bigger element can be guaranteed satisfied reliability.This requires effective reason is because of having big oxide compound standard enthalpy of formation Δ H when element
f 0During value, even to a certain extent little this element of Pauling electronegativity value also is difficult to form its oxide compound.
Among the present invention, when definite Pauling electronegativity value, determines with each valence state that is fixed to each family's element, and when settling the standard Enthalpies of Formation Δ H
f 0The definition that Shi Yingyong is identical.
That is, this value defined is the standard enthalpy of formation Δ H of element when oxide compound constitutes with the valence state separately of following each family's element
f 0
That is, the element in 1 family adopts unit price; Element in 2 families adopts divalence; Element in 3 families adopts trivalent; 4 families element in 10 families adopts divalence; Element in 11 families adopts unit price; Element in 12 families adopts divalence; Element in 13 families adopts trivalent; Element in 14 families adopts tetravalence; Element in 15 families adopts trivalent; Element in 16 families adopts divalence; Element in 17 families adopts unit price; Element in 18 families adopts zeroth order.Yet, under the situation of transition metal, can not easily determine the standard enthalpy of formation Δ H of its oxide compound
f 0, because it forms oxide compound with various valence states.Typically, the valence state of element that forms its oxide compound is high more, the standard enthalpy of formation Δ H of this oxide compound
f 0Low more.
In other words, it is believed that under the situation of transition metal, easily form its oxide compound or multiple oxide compound because can form oxide compound with various valence states, and therefore among the present invention transition metal be not preferably used as element L.
For example, because V (vanadium) adopts divalence, the standard enthalpy of formation Δ H of V (vanadium) oxide compound
f 0The value that adopts is the standard enthalpy of formation Δ H of VO
f 0=-431 (kJmol
-1), and it falls into the requirement (II) of the present invention to element L.Yet V (vanadium) also forms oxide compound such as V easily
2O
3(trivalent), V
2O
4(tetravalence), V
2O
5(pentavalent).The Δ H of these oxide compounds
f 0Value is respectively V
2O
3(1,218kJmol
-1), V
2O
4(1,424kJmol
-1), V
2O
5(1,550kJmol
-1), and these values do not fall into the requirement (II) of the present invention to element L.That is, suppose that V-arrangement becomes almost only be that the oxide compound of divalence, V (vanadium) fall into requirement of the present invention (I) and (II), yet V (vanadium) forms oxides, divalent oxide compound in addition easily, and this oxide compound is easy to oxidizedly, promptly becomes more stable status.Therefore, these oxide compounds are excluded out the preferred element L of the present invention.
The explanation of this eliminating is not clearly described in the requirement to element L in the present invention with " not comprising transition metal ".
To sketch standard enthalpy of formation Δ H herein,
f 0
Typically, chemical reaction is represented by following chemical equation (2):
H
2(gas)+(1/2) O
2(gas)=H
2O (liquid) .... (2)
The chemical equation left side is called initial system, and its right side is called product.Be attached to the preceding coefficient of molecule and be called stoichiometric coefficient.
The heat of the turnover relevant with the chemical reaction of this system is called reaction heat under the steady temperature, and the reaction heat under constant voltage is called heat of reaction at constant pressure.
Under a lot of situations, under typical laboratory condition, reaction heat is measured under constant voltage, therefore, typically uses heat of reaction at constant pressure.Heat of reaction at constant pressure equals poor " the Δ H " of the enthalpy between product and initial system.
The reaction that is expressed as Δ H＞0 is called thermo-negative reaction, and the reaction that is expressed as Δ H＜0 is called thermopositive reaction.
Form being called of reaction heat that the reaction of compound produces by the chemical element of compound and generate heat or Enthalpies of Formation.Under standard conditions, form the reaction heat that the reaction of one mole compound produces and be called standard enthalpy of formation from the chemical element of this compound.Under standard conditions, standard enthalpy of formation is marked with specified temperature (typically being 298K), and at 0.1M Pa or be similar under the 1 atmospheric pressure, and standard enthalpy of formation is by symbol Δ H
f 0Expression.Under standard conditions, the enthalpy of stipulating each chemical element is zero.
Therefore, we can say that the standard enthalpy of formation value negative value more little or this standard enthalpy of formation of oxide compound of element is big more, this oxide compound is stable more and this element is oxidized easily.
The concrete value record of standard enthalpy of formation exists, and for example, in " Electrochemistry Handbook Vol.5 " (Denki-kagaku Binran), it is by The Electrochemistry Society of Japan, and Maruzen edits).
Because standard enthalpy of formation Δ H
f 0Depend on predetermined element and which kind of valence state to introduce molecule with and change, when the standard enthalpy of formation of the oxide compound of each element of determining among the present invention, use above-mentioned requirements to form its oxide compound.
Have Pauling electronegativity value 1.65 or bigger and its oxide compound standard enthalpy of formation Δ H
f 0Be-1,000 (kJ/mol
-1) or the example of bigger element comprise Zn, Cd and In.For the Pauling electronegativity value of the definition according to the present invention, these elements are defined as follows respectively: Zn (1.65), Cd (1.69) and In (1.78).Standard enthalpy of formation Δ H for definition according to the present invention
f 0, they are defined as follows respectively: Zn (348kJmol
-1), Cd (258kJmol
-1) and In (925kJmol
-1).
The total amount of element L is preferably 1.25 or littler to the atomic quantity ratio of bismuth.
Because recording layer of the present invention is based on such supposition: it comprises bismuth as the main component of recording layer and also comprise the Bi oxide compound, when the total amount of element L to the atom number of bismuth than greater than 1.25 the time, can't obtain the inherent record and reproduce performance.
Further, consider the storage stability that improves recording layer, preferably in recording layer, add B, P, Ga, Se, Pd, Ag, Sb, Te, W, Pt and Au as element L.The improvement of storage stability is caused by the following fact probably: by strengthening that from atom to atom bonding force is difficult to break the crystalline structure that once forms or as the atom of different size (side-by-side) when existing shoulder to shoulder, because the atom of reduced size can be present in the lattice of large-size atom crystalline structure is stablized.Especially, element such as B and Pd are attached to oxygen, and when Bi and O coexistence stable amorphous structure effectively.Therefore the structure of stable crystal, this causes the repeatedly improvement of the storage stability of reading ﹠ recording medium of this write-once.
In Write-once-read-many optical recording medium of the present invention, preferably by using wavelength to carry out recording of information and reproduction as 680nm or littler laser beam.Be different from dyestuff, therefore recording layer of the present invention has suitable uptake factor and has high specific refractory power under wide wavelength region, can be used on laser beam under 680nm or the littler red optical maser wavelength and write down and reproduce and obtains excellent record and reproduction performance and high reliability.Wherein, most preferred advantage is to write down and reproduce with wavelength 450nm or littler laser beam.This is to be suitable for the Write-once-read-many optical recording medium that uses with wavelength 450nm or littler laser beam especially as main component and complex refractive index with recording layer of Bi oxide compound because have bismuth.
Preferably have following structure according to Write-once-read-many optical recording medium of the present invention, yet they are not limited to this structure especially.
(A) substrate, recording layer, top coating and reflecting layer
(B) substrate, undercoat, recording layer, top coating and reflecting layer
(C) substrate, reflecting layer, top coating, recording layer and tectum
(D) substrate, reflecting layer, top coating, recording layer, undercoat and tectum.
Further, based on above-mentioned structure, can the cambial structure of multilayered structure.For example, when forming with bilayer, can have following structure: substrate, recording layer, top coating, reflecting layer or semitransparent layer, binder layer, recording layer, top coating, reflecting layer and substrate based on structure (A).
For undercoat and top coating, can use following oxide compound and non-oxidized substance: the example of oxide compound comprises simple oxide such as B
2O
5, Sm
2O
3, Ce
2O
3, Al
2O
3, MgO, BeO, ZrO
2, UO
2, and ThO
2Silicate such as SiO
2, 2MgOSiO
2, MgOSiO
2, CaOSiO
3, ZrO
2SiO
2, 3Al
2O
32SiO
2, 2MgO2Al
2O
35SiO
2, Li
2OAl
2O
34SiO
2Two (double) oxide compounds such as Al
2TiO
5, MgAl
2O
4, Ca
10(PO
4)
6(OH)
2, BaTiO
3, LiNbO
3, PZT[Pb (Zr, Ti) O
3], PLZT[(Pb, La) (Zr, Ti) O
3], and wustite.The non-oxidized substance example comprises nitride such as Si
3N
4, AlN, BN and TiN; Carbide such as SiC, B
4C, TiC and WC; Boride such as LaB
6, TiB
2, and ZrB
2Sulfide such as ZnS, CdS and MoS
2Silicide such as MoSi
2With carbon such as decolorizing carbon, graphite and diamond.
Organic materials such as dyestuff and resin also can be used for undercoat and top coating.
The dyestuff example comprises polymethine (polymethine) dyestuff, naphthalene cyanines (naphthalocyanine) dyestuff, phthalocyanine pigment, side's acid (squarylium) dyestuff, chroconium dyestuff, pyrylium dye, naphthoquinone dyestuff, anthraquinone (indanthrene) dyestuff, xanthene dyestuff, triphenhlmethane dye, Azulene dyestuff, tetrahydrochysene choline (tetrahydrocholine) dyestuff, luxuriant and rich with fragrance dyestuff, triphen thiazine dyes, azoic dyestuff, first
The metal complexes of dyestuff and these compounds.
The example of resin comprises polyvinyl alcohol, polyvinylpyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral acetal, polycarbonate and polyolefine.Various these resins can use separately or two or more are used in combination.
The layer that comprises organic materials can form by modes such as the typical vapour deposition of using, sputter, CVD (being chemical vapour deposition), solvent application.When using coating process, above-mentioned organic materials etc. are dissolved in the organic solvent and this solvent is coated with by normally used coating process such as spraying, roller coat, dip-coating and spin coating.
Typical organic solvent example to be used comprises that alcohol is as methyl alcohol, ethanol and Virahol; Ketone such as acetone, methylethylketone and pimelinketone; Acid amides such as N,N-dimethylacetamide and N, dinethylformamide; Sulfoxide such as methyl-sulphoxide; Ethers such as tetrahydrofuran (THF), diox, ether and ethylene glycol monomethyl ether; Ester such as ritalin and vinyl acetic monomer; Aliphatic halogenated hydrocarbon such as chloroform, methylene dichloride, ethylene dichloride, tetracol phenixin and trichloroethane; The fragrance same clan such as benzene, dimethylbenzene, monochloro benzene and dichlorobenzene; Cellosolve such as methyl cellosolve and ethoxy ethanol; With hydro carbons such as hexane, pentane, hexanaphthene and methylcyclohexane.
About the reflecting layer, use the light reflecting material that laser beam is had highly reflective.
The example of light reflecting material comprises metal such as Al, Al-Ti, Al-In, Al-Nb, Au, Ag and Cu, semi-metal, and alloy.These materials can use separately separately or two or more are used in combination.
When the reflecting layer forms with alloy, can prepare the reflecting layer as target material with by sputter by using alloy.In addition, the reflecting layer also can form by target upper prong (tip-on-target) method (for example, the Cu tip places on the Ag target material and forms the reflecting layer) with by cosputtering (for example, using Ag target and Cu target).
Also can alternately pile up low-index layer and height-index layer and form multilayered structure used as the reflecting layer.
For example, can form the reflecting layer by sputter, ion plating, chemical vapour deposition and vacuum moulding machine.This reflecting layer preferably has thickness 5nm-300nm.
The material that is used for substrate is not particularly limited, as long as they have excellent heat and mechanical property, and when record with reproduce when carrying out from base side with by substrate, they also have the light transmission performance of excellence.
Particularly, the example comprises polycarbonate, polymethylmethacrylate, amorphous polyolefin, cellulose acetate, polyethylene terephthalate, wherein optimization polycarbonate and amorphous polyolefin.
The thickness of substrate depends on to be used and variation and not qualification especially.
The material that is used to form the protective layer on reflecting layer, optical clear layer etc. is not specifically limited, as long as this material can protect reflecting layer, optical clear layer etc. not to be subjected to external force.The example of organic materials comprises thermoplastic resin, thermosetting resin, electron beam curing resin and ultraviolet curable resin.The inorganic materials example comprises SiO
2, Si
3N
4, MgF
2, and SnO
2
On reflecting layer and/or optical clear layer etc., can use thermoplastic resin and/or thermosetting resin to form protective layer.At first, thermoplastic resin and/or thermosetting resin are dissolved in the suitable solvent and prepare coating solution.Then, this coating solution is applied on reflecting layer and/or the optical clear layer and drying forms protective layer thus.
Use the protective layer of ultraviolet curable resin can be on reflecting layer and/or optical clear layer or be dissolved in the suitable solvent ultraviolet curable resin with the preparation coating solution and this coating solution is applied on reflecting layer and/or the optical clear layer by direct coating ultraviolet curable resin, then to the coating solution irradiation ultraviolet radiation so that its sclerosis and forming.
For ultraviolet curable resin, for example can use acrylate resin such as urethane acrylate, epoxy acrylate and polyester acrylate.
These materials can use separately separately or two or more are used in combination, and can not only form with individual layer but also with multilayered structure.
For the method that forms protective layer, use coating process such as spin coating and mold (casting), sputter, chemical vapour deposition etc., wherein preferred spin coating.
Protective layer thickness typically is 0.1 μ m-100 μ m among the present invention, however preferred 3 μ m-30 μ m.
Further, substrate can be arranged on reflecting layer or the optical clear laminar surface.Reflecting layer and optical clear layer can be arranged to face mutually.After arranging that reflecting layer and optical clear layer are faced mutually, but lamination two film optical recording media.
In addition, ultraviolet curable resin layer, inorganic resin layer etc. can be formed on the mirrored sides of substrate to protect the surface and/or to prevent that dust from adhering on it.
When the lens with high-NA are used for than high record density, should form optical clear layer or tectum.Along with numerical aperture increases, the part that playback light passes through must have the thickness of reduction.This is because when the optical axis of the offset from vertical optical pick-up of dielectric surface aberration (aberration) can take place, and this deviation angle is that so-called inclination angle is along with the numerical aperture increase and reduce.The inverse of this inclination angle and optical source wavelength multiply by product square proportional of numerical aperture of objective and for the aberration sensitivity that is caused by substrate thickness.Aberration in order to reduce to be caused by substrate thickness reduces substrate thickness.
For this reason, some optical record mediums are proposed, for example, wherein substrate, be formed on the optical record medium that has jog or irregular recording layer, reflecting layer and optical clear layer in the substrate or arrange with laminate structure with this order as euphotic tectum, wherein this playback light from the irradiation of optical clear layer to reproduce the information the recording layer.Another embodiment is arranged sequentially in suprabasil optical record medium for wherein reflecting layer, recording layer and optical clear layer or tectum with optical transparency with this, wherein playback light from the irradiation of optical clear layer to reproduce the information the recording layer.These optical record mediums can allow to use the object lens with high numerical aperture by the thickness that reduces the optical clear layer.That is, by record and/or information reproduction on the medium with glimmer transparent layer, can carry out the record of higher density, wherein playback light shines from the optical clear layer.
Tectum can typically comprise polycarbonate sheet or ultraviolet curable resin.The tectum of Shi Yonging can comprise that binder layer arrives adjacent layer with bonding tectum herein.
Hereinafter, will in detail openly be suitable for the sputtering target with optical record medium of the recording layer that comprises Bi, Fe and oxygen of the present invention, and manufacture method.
Sputtering target according to the present invention comprises Bi, Fe and O.This sputtering target is used to form the recording layer of optical record medium suitably, and it is used in laser beam under 550nm or the littler wavelength and writes down and reproduce.
Detect the relation between optical extinction coefficient k (it is one of optical constant and is the coefficient of expression photoabsorption degree) and the optical wavelength.When the k value was zero, its expression did not have the absorption of light, and along with the k value increases, photoabsorption increases.Use recording layer that the sputtering target of the Bi of comprising of the present invention, Fe and O forms under 600nm or bigger wavelength, to have and approach zero absorb light and be about zero k value, therefore, be difficult to recorded information.Yet the k value becomes big suddenly and can excellent ground record under less than the wavelength of 550nm.Especially, near the wavelength of 400nm, it is bigger that photoabsorption becomes basically, shows quite excellent performance as the recording layer of optical record medium.
Sputtering target of the present invention preferably includes the composite oxides of Bi oxide compound and Fe oxide compound or Bi and Fe.This sputtering target can comprise the composite oxides of Bi and Fe and further comprise one or more that are selected from Bi oxide compound and Fe oxide compound.Such situation can be arranged: wherein depend on composition, Bi oxide compound or Fe oxide compound remain in the sputtering target and do not make the mixture of Bi and Fe be in well balanced state.The one side of sputtering target comprises Bi oxide compound and Fe oxide compound, the perhaps composite oxides that comprise Bi and Fe on the other hand of sputtering target, or also comprising the composite oxides of Bi and Fe and further comprising one or more that are selected from Bi oxide compound and Fe oxide compound on the one hand at sputtering target.Above-mentioned any aspect, use the optical record medium of the above sputtering target manufacturing to represent excellent performance.Especially, by comprising the component of Bi oxide compound as recording layer, the recording layer of manufacturing can comprise the Bi oxide compound.Because record mark can be by excellent ground of deposit B i metal record, using the sputtering target that comprises the Bi oxide compound is significantly effectively.
Sputtering target of the present invention preferably includes one or more of the composite oxides that are selected from Bi oxide compound, Fe oxide compound and Bi and Fe, and this oxide compound preferably has the oxide compound of a small amount of oxygen of comparing with stoichiometric composition.As the composite oxides of Bi oxide compound, Fe oxide compound or Bi and Fe and the example with oxide compound of a small amount of oxygen of comparing with stoichiometric composition comprise BiOx (x＜1.5), FeOx (x＜1.5), BiFeOx (x＜3), Bi
25FeOx (x＜40) and Bi
36Fe
2Ox (x＜57).Improve metallicity by the amount that reduces oxygen, realize sputter by using direct supply (DC power supply).The advantage of DC sputter be the equipment that is used for making than the equipment that is used for the RF sputter cheap and equipment that use in the DC sputter than the equipment that is used for RF sputter miniaturization more.When the DC sputter form layers, the amount of oxygen can be introduced oxygen by the outside and controls in the layer.By adopting the DC sputter, be easy to the controlling recording performance.
At Bi metal and Fe
2O
3Mix the sputtering target that the back calcining has a small amount of oxygen of comparing with stoichiometric composition.The target that also can have a small amount of oxygen by the method manufacturing that reduces the amount that is present in oxygen in the target as controlled temperature.
Sputtering target of the present invention preferably includes and is selected from BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more as main component.As above-mentioned, use the optical record medium of the recording layer that comprises Bi, Fe and oxygen to represent excellent record performance.Had and contained the sputtering target that Bi, Fe and oxygen are used for magnetooptic recording and have garnet structure, yet, consider the composition that is used to form garnet structure, described sputtering target does not comprise that the compound that uses among the present invention is as main component.Also there is not to use the sputtering target that comprises Bi, Fe and three kinds of elements of oxygen so far, because can not only form garnet structure with these three kinds of elements.In addition, the present invention does not relate to Magnetooptic recording medium, and the present invention relates to be used to form the sputtering target of the layer (it is called the BiFeO layer hereinafter) that mainly comprises Bi, Fe and oxygen, this layer is used for not using the optical record medium of magnetic, is used for the Write-once-read-many optical recording medium of energy high density recording especially.
This sputtering target preferably is made up of three kinds of element Bis, Fe and oxygen.
In this case, sputtering target can comprise the impurity element except that these three kinds of elements, yet, preferably do not comprise the trace element that can weaken layer performance.
Sputtering target of the present invention is by the powder manufacturing of mixing and calcining raw materials oxide compound.Can use the calcined powder and the Fe oxide powder of Bi oxide compound to make sputtering target.Also can be by preparing the compound powder that mainly comprises Bi, Fe and three kinds of elements of oxygen and then calcining this powder and make sputtering target.As method for calcinating, can use pressure-Re method for calcinating such as hot pressing, thermal balance pressurization or HIP.For calcining temperature, preferred higher temperature strengthens sputtering target intensity, yet, under the situation of the compound that comprises Bi, Fe and three kinds of elements of oxygen, issue in about 800 ℃ or higher temperature that looks is separated and/or fusing, and be difficult to calcine equably.So, must control this calcining temperature makes it be not more than about 750 ℃.
Especially, wherein use and comprise and be selected from BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more form the BiFeO layer as sputtering targets of main component and represent excellent performance as the optical record medium of recording layer.BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57Existence can check by the mode of X-ray diffraction.For source of radiation, use Cu to be 5 °-60 ° and measure with 2 θ angles of X-ray diffractometer.The term main component is meant and contains high-content or extra best best % in compound.Typically, the material that represents the maximum diffraction peak as the result of X-ray diffraction analysis can be defined as main component, yet this content can be not proportional with the diffraction peak scale.Sputtering target comprises and is selected from BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57Two or more elements be meant that as the situation of main component identical and these two or more compounds contents of the content separately of these two or more compounds are higher than other components contents.
Sputtering target preferably includes Bi
2O
3And/or Fe
2O
3Have and use the sputtering target that comprises these compounds to form the BiFeO layer represents excellence as the optical record medium of recording layer performance.Bi
2O
3And/or Fe
2O
3Existence can detect by the mode of X-ray diffraction.For source of radiation, use Cu at 2 θ angles to be 5 °-60 ° and measure down.
Be used for determining BiFeO
3, Bi
25FeO
40, Bi
36Fe
2O
57, and Bi
2O
3, and Fe
2O
3The X-ray diffraction analysis of composition in, when expectation 2 θ angles to diffraction peak to be detected were defined as θ 1, the material that in fact has diffraction peak in θ 1 ± 1 degree scope was defined as being included in the above-claimed cpd.
In X-ray diffraction analysis, lattice parameter changes and is depending on that reason as the internal stress of measuring temperature, layer, the X ray wavelength error of measurement and the angle place of the appearance diffraction peak that composition is offset deviation takes place.For known material, what angle detecting diffraction peak in can know by using ASTM (American Society for Testing and Material) card and JCPDS retrieval.When analytic sample when identifying component, be extensive use of the chart of ASTM card and JCPDS card.Term JCPDS represents Joint Committee on Powder Diffraction Standards, and the figure of the X-ray diffraction pattern that its tissue of serving as reasons InternationalCenter for Diffraction Data by name provides, and the chart of having stored many reference material diffraction patterns is used for retrieval.Chart with the x-ray diffraction pattern master drawing of sample of unknown component and reference material relatively, and definite x-ray diffraction pattern master drawing is corresponding with which kind of reference material or be closely related.By this comparison, identify sample material.Using the authentication method of JCPDS card figure is widely used in the world method, as the description of X-ray Diffraction Analysis Rules in X-ray Diffraction Analysis Rules and the Japanese Industrial Standards (JIS) and shown in the X-ray Diffraction Analysis Ceramics Basic Structure 3 that is edited by Tokyo Institute ofTechnology.In measurement, check that the figure of X-ray diffraction pattern with unknown component material and which kind of reference material is corresponding or be closely related definite then this material.
nλ＝2d sinθ
In above-mentioned equation, n represents positive integer, and λ represents wavelength, and d represents the distance of crystal face and the supplementary angle that θ represents grazing angle or input angle.
Because be suitable for the Bragg rule, diffraction peak also appears on the position of the integral multiple that the higher angular side n of 2 θ represents.Can identify material by when analyzing, analyzing the peak position of representing by integral multiple based on the diffraction peak of 2 θ.As above-mentioned, in X-ray diffraction analysis, lattice parameter changes, with since measure temperature, layer internal stress, measurement the X ray wavelength error and form the angle place that diffraction peak appears in skew etc. deviation take place, therefore, when peak that material has is near the angle that the known substance diffraction peak occurs, can determine that this material is corresponding to the known substance with this diffraction peak.
For the diffraction peak deviation, for example, research BiFeO
3The peak of 2 θ that standard map (reference code 20-0169) finds=22.491 degree.The measuring result of four sputtering targets observing in the same manner respectively and make under the same conditions.BiFeO
3The 2 θ number of degrees of normal data be 22.491 °.On the other hand, to show slight deviation respectively be 22.380 °, 22.500 °, 22.420 ° and 22.420 ° to these targets.When replicate measurement, studies show that the deviation of spending approximately ± 1 is in the limit of error of measuring.Therefore, though observe ± 1 the degree diffraction peak angle in deviation, also can be defined as known peak.For example, when material have from 22.491 ° ± 1 the degree deviation the peak time, the BiFeO that can be defined as describing among the present invention
3Be included in this material.Comprise Bi, Fe and O and have at the sputtering target of the diffraction peak at 22.380≤2 θ≤22.500 places effective especially on record performance.
Similarly, according to Bi
36Fe
2O
57Normal data, Bi
36Fe
2O
57Have peak 2 θ=27.681 degree.Measure above-mentioned four targets, the peak of finding them is at 27.65 °, 27.64 °, 27.76 ° and 27.67 °.
According to Bi
25FeO
40Normal data, its peak is at 2 θ=27.683 degree.Measure this four targets, the peak of finding them is respectively at 27.66 °, 27.64 °, 27.76 ° and 27.68 °.
Because in replicate measurement, cause the deviation of degree approximately ± 1, think in 2 θ of any of these material ± 1 degree deviation falls in the measuring error scope.
Preferably, sputtering target does not further comprise Bi
2Fe
4O
9Along with Bi content increases, Bi
2Fe
4O
9Content tend to reduce.Can detect Bi by the X-ray diffraction mode
2Fe
4O
9Existence.For source of radiation, using Cu is 5 ° of-60 ° of measurements with 2 θ angles of X-ray diffractometer.Find to use and wherein discerned Bi by the X-ray diffraction mode
2Fe
4O
9The optical record medium that the sputtering target formation BiFeO layer that exists is used for recording layer does not represent record performance satisfactorily and is not suitable for high density recording.
The Co that sputtering target preferably has, Ca and Cr content are less than detectability.When use comprised the sputtering target of impurity, the layer of formation also comprised impurity element.In optical recording, shining laser beam on the recording layer by absorption increases the recording layer temperature and causes physics or chemical transformation carries out record.Term physics or chemical transformation are meant and change as crystallization etc.Because the variation of Tc is different with crystalline size when crystallization, preferably do not use the layer that is used for recording layer that contains impurity.
For the detection of impurity, analyze composition quantitatively by the mode of inductively coupled plasma emission spectrometric method.When analyzing oligo-elements, this analysis is suitable, even and when using this analysis, sputtering target preferably has Co, Ca and Cr content less than this detectability.
It is 65%-96% that sputtering target preferably has tamped density.
The sputtering target tamped density is high more, and target strength is high more and because its cambial time of highdensity element is tending towards shortening, simultaneously, the composition difference between the layer of target and formation is tended to increase.Such situation can be arranged: wherein can be close with the composition of layer by the composition that reduces the target density target, however the layer that the target that density reduces not only causes postponing forms the problem of speed, also causes the own fragility of target when form layers and the problem of fragmentation.Herein, the term tamped density is represented the value as density that obtains by target weight that reality is made and the target weight ratio of being calculated with 100% timing by designated substance when target weight.
Table 1 shows the tamped density of target, during the form layers or the target state after forming and as the Bi that uses diameter 76.2mm and thickness 4mm
10Fe
5Wherein be formed with the record performance of the recording medium of layer during the Ox target.When tamped density is 50% or more hour, even after calcining, can not form target as sputtering target.Tamped density is 61%, can form target, yet it is easy to broken immediately after applying the electric power of 100W.Tamped density is 98%, and this density is too high and this target is very hard so that be easy to fragmentation.Tamped density 65%-96%, target can form without a doubt, and represents excellent record performance.Even tamped density is 61% and 98%, form layers obtains excellent record performance under the cracked condition of target by guaranteeing when the form layers not take place.From The above results as seen, the preferred 65%-96% of the tamped density of sputtering target.
Table 1
| Tamped density (%) | The target | Record performance | |
| 50% or littler | Can not form target | ||
| 61% | Be easy to impaired by applying the 100W radio frequency power.Impaired at 50W. | Excellent | |
| 65% | May form sputtering target by applying the 100W radio frequency power. | Excellent | |
| 83% | May form sputtering target by applying the 100W radio frequency power. | Excellent | |
| 96% | May form sputtering target by applying the 100W radio frequency power. | Excellent | |
| 98% | Be easy to impaired by applying the 100W radio frequency power.Impaired at 50W. | Excellent |
The Bi that sputtering target preferably has is to satisfied Bi/Fe 〉=0.8 that concerns of the atomic ratio of Fe.Optical record medium with the BiFeO-layer that uses this target formation represents excellent performance and is particularly suitable for height-density record.
In theory, comprise Bi based on the supposition use
25FeO
40As the sputtering target of main component, be limited to 25 on the Bi/Fe ratio, yet in fact, it is about 15.Sputtering target manufacture method of the present invention relates to by calcining Bi
2O
3And Fe
2O
3Powder is made the method for BiFeO target of the present invention.Bi
2O
3Oxide compound with Bi exists natively, Fe
2O
3Oxide compound with Fe exists.By dry method or these powder of wet pulverization and then be classified as the homogeneous granules diameter.Then, be in atmosphere, to calcine under 750 ℃ with this powder mixes, heating and extruding then to be shaped keeping temperature.By the intensity that repeats to pulverize the incinerating target again and can improve this sputtering target by the method for heating and extrusion molding.By the mode of metal solder or resin bond, above-mentioned incinerating target is attached on the backing plate of being made by oxygen free copper can obtains sputtering target.
The present invention also proposes to comprise the optical record medium of the BiFeO layer that uses sputtering target formation of the present invention.In this optical record medium, form necessary layer on the resin base of polycarbonate etc. comprising.Groove can be formed on resin base and pit is controlled track (tracking) etc.Introduce simultaneously argon gas formation BiFeO-layer in a vacuum by applying radio frequency power.In addition, metal level and the protective layer that is used to improve performance can be arranged as the reflecting layer.
Concentrate in the above-mentioned paragraph and described sputtering target of the present invention on the optical record medium, the application of sputtering target of the present invention is not limited to optical record medium and can be used for other purpose, as long as the performance of this layer meets the demands.For example, sputtering target can be used to form the thin layer made by magneticsubstance, be used to form and make light guide with the thin layer of isolator be used to form the photoswitch thin layer.
For the rough production line that forms this sputtering target, can take following programstep: to raw material weigh, by dry ball milling mixing, hot pressing, shaping and bonding.Also spendable is to take following programstep: raw material weighs, by dry ball milling mixing, spraying drying, hot pressing, shaping and bonding.
According to the present invention, repeatedly reading ﹠ recording medium of write-once can be provided, it can stably write down little record mark under the modulated amplitude of higher degree.Use the other element of also not finding up to now, the Write-once-read-many optical recording medium that has excellent record and reproduce Performance And Reliability can be provided.
Further, the present invention can provide sputtering target, and the layer with stable The Nomenclature Composition and Structure of Complexes that it is applicable to any formation provides its manufacture method and the height-density optical record medium that uses this target also can be provided.
Hereinafter, to describe the present invention in detail based on optical record medium and Write-once-read-many optical recording medium with reference to specific embodiment, this optical record medium comprises that recording layer and this Write-once-read-many optical recording medium of wherein using the material of being represented by BiOx (0＜x＜1.5) of the present invention comprise that Bi, M and oxygen constitute element as recording layer, yet the present invention is not limited to disclosed embodiment.
Embodiment A-1
Be formed with thereon in polycarbonate-substrate of the guide groove that depth of groove is 21nm (guide groove), by sputter form have by BiOx (0＜x＜1.5) expression form and the layer of thickness 10nm to obtain Write-once-read-many optical recording medium of the present invention.At radio frequency power is that 100W and Ar airflow rate are under the 40sccm, uses to have Bi
2O
3Composition and diameter are that the sputtering target of 76.2mm forms this layer.
Use under the 405nm wavelength under the following conditions by PULSTEC INDUSTRIAL CO., the lens numerical aperture that LTD. makes is that 0.65 the DDU-1000 of disc evaluation system carries out record to this optical record medium.
Modulating mode: 1-7 modulation
Registration line density: the shortest mark lengths (2T)=0.231 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state (normal) equalizer
As a result, be in continuous recording part, to obtain 9.9% excellence shake (jitter) value under the 5.2mW and realized that modulated amplitude is scale-of-two (binary) record performance of 55% excellence at recording power.
Embodiment A-2
Be formed with depth of groove thereon and be in the polycarbonate-substrate of guide groove of 21nm, have the layer of Fe and O and thickness 10nm to obtain Write-once-read-many optical recording medium of the present invention by sputter.At radio frequency power is that 100W and Ar airflow rate are under the 40sccm, uses to have Bi
10Fe
5O
xComposition and diameter are that the sputtering target of 76.2mm forms this layer.This target is 2: 1 Bi by the calcining ratio
2O
3And Fe
2O
3The mixture preparation.It should be Bi in theory
10Fe
5O
22.5Yet,, because the oxygen that leaks in method for calcinating, the amount of oxygen can not accurately be measured, and therefore oxygen is expressed as O
X
Use under the 405nm wavelength under the following conditions by PULSTEC INDUSTRIAL CO., the lens numerical aperture that LTD. makes is that 0.65 the DDU-1000 of disc evaluation system carries out record to this optical record medium.
Modulating mode: 1-7 modulation
Registration line density: the shortest mark lengths (2T)=0.231 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, be in continuous recording part, to obtain 8.9% excellent jitter value under the 5.8mW and realized that modulated amplitude is the binary recording performance of 52% excellence at recording power.
Embodiment A-3
Use is made in embodiment A-1 and the Write-once-read-many optical recording medium that is used to write down reflects EELS and measures.Scanning Auger (Auger) the Electron Energy Disperse Spectroscopy PHI4300 that improvement is made by Perkin-Elmer is used for measuring.EELS represents electron energy loss spectroscopy (Electron Energy LossSpectroscopy), and be wherein electron irradiation to the sample to measure the energy distribution spectroscopy system of the electronics of scattering by interacting with the sample outside surface.When the primary electron of certain energy excites the inner shell of atom to be measured, discharge the electronics of certain energy, cause the scattering of primary electron.In this process, by having lost some energy with the interaction of contiguous atom.Therefore, by checking the mode of electron scattering, can obtain information as the radial distribution function(RDF) of contiguous atom.
Based on measuring the EELS power spectrum that obtains, measure near the radial distribution function(RDF) of Sauerstoffatom by EELS.Radial distribution function(RDF) is illustrated near the probability of the electronics existence of atom and can calculates and infer the valence state and the structure of atom.In analysis software package, be extensive use of the FEFF software of publishing by Washington University based on the photoelectron multiple-scattering theory.By use this analysis software with the relative actual measured value reference of calculated value, can infer valence state number and structure.
Fig. 1 shows the value of the radial distribution function(RDF) of measuring by aforesaid method.
Fig. 2 shows the radial distribution function(RDF) that uses FEFF to calculate.This radial distribution function(RDF) that illustrates is respectively the tervalent situation of Bi-that adopts Bi; Yet the structure that the Bi-trivalent adopts is β-Bi
2O
3Situation; With Bi-quaternary BiO
2Situation.
Relatively these radial distribution function(RDF)s show near the peak 6 dusts 1011 and 1012 in recording section highlightedly.When these two whens figure relatively, peak 1011 and 1012 mates mutually.This has proved BiO
2, i.e. the BiO of tetravalence Bi
2Be present in the recording section.
Write-once-read-many optical recording medium with this record mark can have the higher modulation amplitude excellence record and realize height-density record.
Hereinafter,, will the present invention be described in further detail based on the Write-once-read-many optical recording medium that uses the other element of element L conduct that uses among the present invention with reference to embodiment and comparative example, yet, the invention is not restricted to these disclosed embodiment.
(Embodiment B-1 to B-18)
Make Write-once-read-many optical recording medium by adopting following structure: wherein polyolefine-substrate (by NIPPON ZEON CO., the ZEONOR that LTD. makes); Comprise that bismuth is as the main component that constitutes the recording layer element and the recording layer of Bi oxide compound; Thermal insulation layer; Form with laminate structure with the reflecting layer, and use following material to be respectively applied for these layers.
Use raw material to make sputtering target, Bi in this raw material
2O
3Mixed in 2: 1 to 5: 1 with ratio with oxide compound, then use this sputtering target to form recording layer so that have thickness and be about 7nm at the element shown in the table 2.
Table 2 has shown the standard enthalpy of formation value Δ H of the oxide compound of the electronegativity value of Pauling separately that obtains of each the element L that adds each recording layer to and element L
f 0Yet,, these are worth based on definition of the present invention.When Pauling electronegativity value is 1.80 or when bigger, the standard enthalpy of formation value Δ H of the oxide compound of element L
f 0Inessential, and therefore some elements of table 2 do not have their Δ H
f 0Value.
As above-mentioned, among the present invention, obtain the Pauling electronegativity value of element L and the standard enthalpy that oxide compound generates with each valence state that is fixed to each family of elements.Valence state separately based on each element of the present invention definition also writes out in table 2.
In table 2, term type A represents to fall into the element L of the present invention's definition (I), and the term type B represents to fall into the element L of the present invention's definition (II).
Material ZnS-SiO
2The thickness that is used for thermal insulation layer and formation with ratio 85: 15 (mole %) is 15nm.
For the reflecting layer, use the Ag alloy and form thickness to be 100nm.
The track pitch at the polyolefin-based end is that 0.437 μ m and thickness are 0.6mm.
Use under the 405nm wavelength under the following conditions by PULSTEC INDUSTRIAL CO., the lens numerical aperture that LTD. makes is that 0.65 the DDU-1000 of disc evaluation system carries out record to these optical record mediums.
As a result, obtain extremely excellent record and reproduce performance, promptly at the jitter value shown in the table 2.
＜record and reproducing condition 〉
Modulating mode: 1-7 modulation
Registration line density: the shortest mark lengths (2T)=0.204 μ m
Line speed record: 6.6m/s
Wave shape equalization: limited (limit) equalizer
Reproducing power: 0.5mW
Then, these Write-once-read-many optical recording mediums are placed on following 100 hours variable quantities with the measurement jitter value of condition of 80 ℃ of temperature and relative humidity 85%.The variable quantity of this jitter value is calculated as follows:
(jitter value after the storage test)-(initial jitter value)
Table 2 shows this result.
Know from table 2 and see that the element that is used for the satisfied definition (I) of element L of the present invention has showed that respectively the excellent initial jitter value and the jitter value of the little degree of test of being stored worsen.
Also showed as long as satisfy definition (I), the standard enthalpy of formation of oxide compound " Δ H
f 0" desirable arbitrary value.
And the element that is used for the satisfied definition of element L of the present invention (II) has showed that respectively the excellent initial jitter value and the jitter value of the little degree of test of being stored worsen.
Table 2
| Sample number | Element L | Valence state | The Pauling electronegativity | Standard enthalpy of formation value Δ H f 0(kJmol -1) | Type | Initial jitter value (%) | The variable quantity of jitter value (%) |
| 1 | |
3 | 2.04 | -1,273 | A | 5.6 | 0.5 |
| 2 | |
3 | 2.19 | A | 6.2 | 0.5 | |
| 3 | |
3 | 1.81 | -1,819 | A | 6.2 | 0.5 |
| 4 | |
2 | 2.55 | A | 6.3 | 0.5 | |
| 5 | |
2 | 2.20 | -85 | A | 5.8 | 0.2 |
| 6 | |
1 | 1.93 | A | 6.1 | 0.3 | |
| 7 | |
3 | 2.05 | -1,440 | A | 5.7 | 0.4 |
| Sample number | Element L | Valence state | The Pauling electronegativity | Standard enthalpy of formation value Δ H f 0(kJmol -1) | Type | Initial jitter value (%) | The variable quantity of jitter value (%) |
| 8 | |
2 | 2.10 | A | 5.7 | 0.4 | |
| 9 | |
2 | 2.36 | A | 5.9 | 0.5 | |
| 10 | |
2 | 2.28 | A | 6.0 | 0.3 | |
| 11 | |
1 | 2.54 | A | 6.2 | 0.3 | |
| 12 | |
2 | 1.69 | -258 | B | 6.2 | 0.5 |
| 13 | As | 3 | 2.18 | -1,313 | A | 6.3 | 0.5 |
| 14 | Re | 2 | 1.90 | A | 6.0 | 0.5 | |
| 15 | |
2 | 2.20 | A | 6.0 | 0.5 | |
| 16 | |
2 | 2.20 | A | 6.0 | 0.5 | |
| 17 | |
3 | 2.04 | -394 | A | 6.2 | 0.6 |
| 18 | |
2 | 2.00 | -90 | A | 6.3 | 0.6 |
In the foregoing description, be used to write down and the wavelength set reproduced at 405nm, yet, by from 15nm to 120nm, regulating thermal insulation layer thickness, be 9% or the littler record that carries out for the laser beam of wavelength 660nm with jitter value excellently.In test, the track pitch of substrate is 0.74 μ m, and record and reproducing condition are based on those conditions of DVD+R.The jitter value amount of the increase that obtains in storage same as the previously described embodiments test provides those the result who is substantially similar to shown in the table 2.
(comparative example B-1)
Make Write-once-read-many optical recording medium according to mode identical in Embodiment B-1, as long as main component is bismuth and uses the recording layer that replaces containing the Bi oxide compound by the recording layer that forms with the sputter of bismuth metal target.Then estimate optical record medium.
Analysis by X-ray photoelectron spectroscopy shows not detect the bismuth oxide compound in recording layer, except in the interface between substrate and recording layer and at recording layer and ZnS-SiO
2Between the interface in.Therefore, proved that the recording layer of making among the comparative example B-1 does not comprise the Bi oxide compound.
As the measuring result of record and reproduction performance, this initial jitter value surpasses 15%, and its not energy measurement shake after the storage test.
From this result, confirmed not only to comprise that bismuth is as main component but also comprise the importance of the recording layer of Bi oxide compound.
(Embodiment B-19)
Be formed with depth of groove thereon and be 50nm and track pitch and be on the polycarbonate substrate of guide groove of 0.40 μ m, thickness is the ZnS-SiO of 65nm
2Layer is that undercoat and thickness are that the BiPdO layer of 15nm is that recording layer is arranged with laminate structure by sputter with this order.Bi is to the atom number ratio of Pd, or Bi: Pd is about 3: 1.
Then, on this recording layer, form by spin coating and to comprise that the pigment represented by following Chemical formula 1 or the organic material layer of dyestuff are that the top coating is about 30nm to have mean thickness.On this organic material layer; comprise that by sputter configuration Ag thickness is the reflecting layer of 150nm and is that the protective layer of 5 μ m is to obtain repeatedly reading ﹠ recording medium of write-once of the present invention thus by being spin-coated on the reflecting layer thickness that further configuration made by ultraviolet-curing resin then.
The material that pigment of being represented by Chemical formula 1 or dyestuff typically are used for common DVD ± R, and this material has little absorption respectively under blueness-optical maser wavelength.
With HD and corresponding to record of DVD-R and reproducing condition under this optical record medium is write down using by PULSTEC INDUSTRIAL CO. at the 405nm wavelength, the numerical aperture that LTD. makes is that 0.65 the DDU-10 of disc evaluation system estimates it.
The measurement of this optical record medium is created in the excellent down value PRSNR 22 of recording power 5.8mW, and has realized excellent record and reproduced performance.
(Embodiment B-20)
Be formed with depth of groove thereon and be 20nm and track pitch and be on the polycarbonate substrate of guide groove of 0.32 μ m, thickness is that reflecting layer, the thickness made by Ag of 100nm is the ZnS-SiO of 16nm
2Layer is that top coating and thickness are that the BiPdO layer of 7nm or recording layer are arranged with laminate structure by sputter with this order.Bi is to the atom number ratio of Pd, or Bi: Pd is about 3: 1.
Then, the thickness that is formed from a resin is that the tectum of 0.1mm is laminated on the recording layer to obtain repeatedly reading ﹠ recording medium of write-once of the present invention.
This optical record medium is write down under according to the record of BD-R and reproducing condition and reproduce to use under the 405nm wavelength by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.85 disc evaluation system estimates it.
The measurement of this optical record medium is created in the jitter value 6.0% of the excellence under the recording power 7.0mW and has realized excellent record and reproduced performance.
(Embodiment B-21)
Make Write-once-read-many optical recording medium according to the mode identical with Embodiment B-19, condition is that the BiBO layer is used for recording layer.Then estimate this Write-once-read-many optical recording medium, Bi is to the atom number ratio of B, and perhaps Bi: B is about 2: 1.
Excellent record and the reproduction performance of available this optical record medium realization that the measurement of this optical record medium has been created in excellent down value PRSNR 23 of recording power 5.6mW and illustration.
(Embodiment B-22)
Make Write-once-read-many optical recording medium according to the mode identical with Embodiment B-20, condition is that the BiBO layer is used for recording layer.Then estimate this write-once and repeatedly read many optical record mediums.Bi is to the atom number ratio of B, and perhaps Bi: B is about 2: 1.
The measurement of this optical record medium is created in the jitter value 5.9% of the excellence under the recording power 6.7mW and has realized excellent record and reproduced performance.
(Embodiment B-23)
Be formed with depth of groove thereon and be 50nm and track pitch and be on the polycarbonate substrate of guide groove of 0.32 μ m, form the reflecting layer of making by Ag that thickness is 100nm by sputter, form by spin coating and to comprise that the pigment represented by Chemical formula 1 or the organic material layer of dyestuff are that the top coating is about 30nm to have mean thickness, the BiBO layer of following thickness and be 15nm is recording layer and ZnS-SiO
2Layer is that undercoat is arranged with laminate structure by sputter with this order.Bi is to the atom number ratio of B, or Bi: B is about 2: 1.
Then, the thickness that will be made by transparent resin is that the tectum of 100nm is laminated on the recording layer, obtains the recording medium that write-once of the present invention repeatedly reads thus.
This optical record medium is write down under according to the record of BD-R and reproducing condition and reproduce to use under the 405nm wavelength by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.85 disc evaluation system estimates it.
The measurement of this optical record medium is created in the jitter value 6.5% of the excellence under the recording power 4.8mW and has realized excellent record and reproduced performance.
(Embodiment B-24)
Be formed with depth of groove thereon and be 40nm and track pitch and be on the polycarbonate substrate of guide groove of 0.74 μ m, thickness is that the BiBO layer of 15nm is that recording layer and thickness are the ZnS-SiO of 40nm
2Layer is that the top coating is arranged with laminate structure by sputter with this order.Bi is to the atom number ratio of B, and perhaps Bi: B is about 2: 1.
Then, on recording layer, arrange that the thickness of being made by Ag is the reflecting layer of 100nm and is the protective layer of about 5 μ m by the thickness that ultraviolet curable resin is made, and obtains the recording medium that write-once of the present invention repeatedly reads thus.
This optical record medium is write down under according to the record of DVD+R and reproducing condition and reproduce to use under the 660nm wavelength by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system estimates it.
The measurement of this optical record medium is created in the jitter value 7.2% under the recording power 12.0mW and has realized excellent record and reproduced performance.
(Embodiment B-25)
Make Write-once-read-many optical recording medium according to the mode identical with Embodiment B-24, condition is that Sb adds in the material of recording layer.Then estimate Write-once-read-many optical recording medium, Bi is to the atom number ratio of Sb, and perhaps Bi: Sb is about 4: 1.
The measurement of this optical record medium is created in the jitter value 7.6% under the recording power 10.0mW and has realized excellent record and reproduced performance.
(Embodiment B-26)
Be formed with depth of groove thereon and be 20nm and track pitch and be on the polycarbonate substrate of guide groove of 0.437 μ m, the BiPdO layer that will have thickness and be 5nm is recording layer and has the ZnS-SiO that thickness is 15nm
2Layer is that the top coating is arranged with laminate structure by sputter with this order.At ZnS-SiO
2On the layer; has the reflecting layer of containing Ag that thickness is 100nm by the sputter setting; and have the protective layer that contains ultraviolet curable resin that thickness is about 5 μ m by further setting of spin coating, obtain Write-once-read-many optical recording medium of the present invention thus.
In Embodiment B-26, in recording layer, change the atom number ratio of Pd total amount, to estimate jitter value to Bi.Record and reproducing condition and Embodiment B-1 are identical in the B18.
The measurement of optical record medium as shown in Figure 3, illustration the Pd total amount with respect to the atom number of Bi than be 1.25 or littler scope in can obtain excellent jitter value.In Fig. 3, this value 1.25 is illustrated by the broken lines.In addition, the element that defines among the present invention except that Pd that gone back illustration also has trend similar to the above respectively.
Then, specifically describe the sputtering target that the present invention relates to reference to embodiment and comparative example, yet the present invention is not limited to disclosed example.
Embodiment C-1
Mix Bi
2O
3And Fe
2O
3Powder is 6: 5 to obtain Bi to the atomic ratio of Fe, then in ball mill by dry mixed 1 hour.Form mixed powder by compacting under 100MPa-200MPa, then under 750 ℃, in atmosphere, calcine 5 hours to obtain sputtering target.The diameter of target is
With thickness be 4mm, this target is attached to by metal solder on the backing plate of being made by oxygen free copper and obtains sputtering target 1.The tamped density of this sputtering target is 75%.
Measure the X-ray diffraction pattern of sputtering target.Measuring condition is as shown in table 3.Fig. 4 represents measuring result.
For the diffraction peak position of determining to obtain in the measurement, search for and detect this diffraction peak position at the diffraction peak position of known substance.The figure that is marked with (a) at Fig. 4 top represents the diffraction pattern of target 1.The figure that is marked with (b) represents the BiFeO based on given data
3The position of diffraction peak.In X-ray diffraction analysis, the position alignment diffraction of material and the data of intensity have collected in the database in the X ray diffracting data source that comes from past measurement.Therefore, the material of measurement can be identified by comparing and measuring diffraction result and former data.As at the BiFeO that relatively is marked with (b)
3Data be marked with the result who searches for after the take off data of (a), find to have mark " ° " diffraction peak be BiFeO
3Diffraction peak.Similarly, the figure that is marked with (c) is Fe
2O
3Given data and the figure that is marked with (d) be Bi
2O
3Given data.Similarly, identify Bi
2O
3And Fe
2O
3Diffraction peak.Maximum peak is corresponding to BiFe
2O
3Diffraction peak, this shows that this compound is a main ingredient.Further, sputtering target is carried out icp analysis, i.e. the inductively coupled plasma emission spectrometric method.The part sputtering target is dissolved in the chloroazotic acid as sample, then is used for analyzing with the ultrapure water dilution.For this solution, difference analytical element Co, Ca and Cr.Analytical results is that the content of each element is less than detectability.
Table 3
| The source | Cu |
| Wavelength | 1.54056 dust |
| Monochromator | Use |
| Tube current | 100mA |
| X-ray tube voltage | 40kV |
| Cover data | The 5-60 degree |
| The source | Cu |
| Scan axis | 2θ/θ |
| Sampling interval | 0.020 degree |
| Sweep velocity | 8.000 degree/minute |
| Divergent slit | 1.00 degree |
| Scatter slit | 1.00 degree |
| Light detects slit | 0.15mm |
Embodiment C-2
Use the sputtering target of preparation in the Embodiment C-1 to make optical record medium.
Be formed with depth of groove thereon and be 50nm and track pitch and be on the polycarbonate substrate of guide groove of 0.44 μ m; has the BiFeO layer that thickness is 15nm by sputter formation; on the BiFeO layer, form and contain the pigment represented by Chemical formula 1 or the organic material layer of dyestuff is about 30nm to have mean thickness by spin coating; the reflecting layer that will be 150nm by the thickness of Ag preparation is arranged on this organic material layer by sputter; and the thickness that will be made by ultraviolet curable resin is that the protective layer of about 5 μ m further is arranged on the reflecting layer by spin coating, obtains repeatedly reading ﹠ recording medium of write-once of the present invention thus.Pigment or the dyestuff represented by Chemical formula 1 typically are used for common DVD ± R material, and this material has little absorption respectively in blueness-optical maser wavelength.
Use under the 405nm wavelength under the following conditions by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths (3T)=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, as shown in Figure 5, under recording power 6.1mW, obtain excellent jitter value 10.2%, and realized excellent record and reproduced performance.
Embodiment C-3
Prepare sputtering target 2 according to the identical mode of Embodiment C-1, condition is to mix Bi
2O
3And Fe
2O
3Powder makes that Bi is 35: 5 to the Fe atomic ratio.The tamped density of this sputtering target is 67%.
Measure the X-ray diffraction pattern of this sputtering target.Measuring condition is as shown in table 3, and Fig. 6 represents the result that measures.
Be the diffraction peak position of determining in measurement, to obtain, with diffraction peak position and known substance contrast.As shown in Figure 6, the major part of diffraction pattern (if not all) peak and Bi
25FeO
40The peak be complementary.Certainly, the climax is Bi
25FeO
40The peak, this proves that this compound is a main component.
Embodiment C-4
The sputtering target that use prepares in Embodiment C-3 is made optical record medium.
Be formed with thereon on the polycarbonate substrate of guide groove of depth of groove 50nm and track pitch 0.44 μ m, thickness is the ZnS-SiO of 50nm
2The BiFeO layer of layer and thickness 15nm is arranged with laminate structure with this order by sputter; containing the pigment represented by following Chemical formula 1 or the organic material layer of dyestuff is formed on the BiFeO layer so that mean thickness is about 30nm by spin coating; thickness is that the reflecting layer that comprises Ag of 150nm is arranged on this organic material layer by sputter; then further be arranged on the reflecting layer, obtain repeatedly reading ﹠ recording medium of write-once thus by the protective layer of making by ultraviolet curable resin of spin coating with the about 5 μ m of thickness.The material that pigment of being represented by Chemical formula 1 or dyestuff typically are used for common DVD ± R, and this material has respectively in the medium and small absorption of blueness-optical maser wavelength.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., the numerical aperture that LTD. makes is that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths (3T)=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, as shown in Figure 7, under recording power 7.0mW, obtain excellent jitter value 8.6%, and realize excellent record performance.
Even when recording power exceeds optimal recording power, can realize having the Write-once-read-many optical recording medium of high modulated amplitude and wide region recording power surplus (margin), and the reproduction of the signal level of recording section or RF level there is not big change yet.
Embodiment C-5
Prepare sputtering target 3 in the mode identical with Embodiment C-1, condition is to mix Bi
2O
3And Fe
2O
3Powder makes that Bi is 1: 5 to the atomic ratio of Fe.The tamped density of this target is 67%.
Measure the X-ray diffraction pattern of this sputtering target.Measuring condition is as shown in table 3.Fig. 8 shows measuring result.
Be the diffraction peak position of determining in measurement, to obtain, this diffraction peak position relatively the diffraction peak of known substance search for and check.As a result, find that sputtering target has corresponding to Bi
2Fe
4O
9, Bi
2O
3, and Fe
2O
3Diffraction peak, yet, other diffraction peaks of this sputtering target not with those peak match(ing)es of known substance.Maximum peak is corresponding to Fe
2O
3The peak, this demonstrates this compound is main component.
Embodiment C-6
The sputtering target that use prepares in Embodiment C-5 is made optical record medium.
Being formed with thereon on the polycarbonate substrate of guide groove of depth of groove 50nm and track pitch 0.44 μ m, is the ZnS-SiO of 50nm with this order with the laminate structure layout thickness by sputter
2The BiFeO layer of layer and thickness 10nm; by be spin-coated on the BiFeO layer form contain the pigment represented by Chemical formula 1 or dyestuff organic material layer so that mean thickness is about 30nm; by sputtering at the reflecting layer of making by Ag that layout thickness on this organic material layer is 150nm; then, obtain repeatedly reading ﹠ recording medium of write-once thus by the further protective layer that comprises ultraviolet curable resin of the about 5 μ m of layout thickness on the reflecting layer of spin coating.The material that pigment of being represented by Chemical formula 1 or dyestuff typically are used for common DVD ± R, and this material has respectively in the medium and small absorption of blueness-optical maser wavelength.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., the numerical aperture that LTD. makes is that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths (3T)=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
It is the 8.1mW jitter value 22.6% of degradation down that this record is created in recording power.
Further, the thickness of BiFeO layer is changed into 15nm and 20nm respectively, yet the jitter value of generation further worsens, and can't measure.
Embodiment C-7
Obtain sputtering target 4 in the mode identical with Embodiment C-1, condition is to mix Bi
2O
3And Fe
2O
3Powder makes that Bi is 4: 5 to the atomic ratio of Fe.The tamped density of sputtering target 4 is 77%.
Measure the X-ray diffraction pattern of this sputtering target.Measuring condition is as shown in table 3.Fig. 9 shows measuring result.
The diffraction pattern that obtains in the measurement is illustrated in that (a) locates among Fig. 9.Diffraction peak position and known substance (b) BiFeO with this sputtering target
3(c) Bi
2Fe
4O
9Diffraction peak contrast.Result for retrieval shows that this sputtering target only has corresponding to BiFeO
3And Bi
2Fe
4O
9Diffraction peak.Maximum peak is corresponding to BiFe
2O
3The peak, this demonstrates this compound is main component.
Embodiment C-8
The sputtering target that use prepares in Embodiment C-7 is made optical record medium.
Be formed with thereon on the polycarbonate substrate of guide groove of depth of groove 50nm and track pitch 0.44 μ m, thickness is the ZnS-SiO of 50nm
2The BiFeO layer of layer and thickness 10nm is arranged with laminate structure with this order by sputter; containing the pigment represented by Chemical formula 1 or the organic material layer of dyestuff is formed on the BiFeO layer so that mean thickness is about 30nm by spin coating; thickness is that the reflecting layer of being made by Ag of 150nm is arranged on this organic material layer by sputter; then the protective layer of being made by ultraviolet curable resin of the about 5 μ m of thickness further is arranged on the reflecting layer by spin coating, obtains repeatedly reading ﹠ recording medium of write-once thus.The material that pigment of being represented by Chemical formula 1 or dyestuff typically are used for common DVD ± R, and this material has respectively in the medium and small absorption of blueness-optical maser wavelength.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.The shortest mark lengths is set in 0.205 μ m to detect the ability of high density recording.
＜record condition 〉
Modulating mode: 1-7 modulation
Registration line density: the shortest mark lengths (2T)=0.205 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
Figure 10 shows the result.
Embodiment C-9
The sputtering target that uses the mode identical with Embodiment C-7 to prepare is made optical record medium in the mode identical with Embodiment C-8, and condition for a change Bi recently prepares this sputtering target to the atom of Fe.Under as the identical record condition of this embodiment, measure this optical recording.Figure 10 shows measuring result.As shown in figure 10, use has the sputtering target by the atomic ratio of Bi/Fe 〉=0.8 expression, be to have the optical record medium that atomic ratio is the sputtering target of Bi/ (Bi+Fe) 〉=4/9 among Figure 10, show that jitter value is about 14%, even and proof under high density recording, also can obtain excellent jitter value.Even use the optical record medium have by the sputtering target of the atomic ratio of Bi/ (Bi+Fe) 〉=3/8 expression, also improved jitter value in fact and it is originally effective.
Embodiment C-10
To prepare sputtering target 5 with Embodiment C-1 and identical mode, condition is to mix Bi
2O
3And Fe
2O
3Powder makes that Bi is 10: 5 to the atomic ratio of Fe.The tamped density of this target is 85%.
Measure the X-ray diffraction pattern of this sputtering target.Measuring condition is as shown in table 3.Figure 11 shows measuring result.
Be the diffraction peak position of the diffraction pattern (a) determining in measurement, to obtain, with the diffraction peak position contrast of this diffraction peak position and known substance (b)-(e).As a result, have corresponding to Bi
25FeO
40, BiFeO
3, Bi
2O
3, and Fe
2O
3Diffraction peak, yet, other diffraction peak of this sputtering target with the diffraction peak of other material coupling.Maximum peak is corresponding to Bi
25FeO
40The peak, this shows that this is a main component.
Sputtering target is carried out icp analysis, i.e. the inductively coupled plasma atomic emission spectrometry.The part sputtering target is dissolved in the chloroazotic acid as sample, then is used for analyzing with the ultrapure water dilution.To this solution difference analytical element Co, Ca and Cr.Analytical results is that the content of each element is less than detectability.
In addition, prepare sputtering target 6 in the same manner as described above, wherein detected the Al of 0.003 quality % and the Co of 0.001 quality % as impurity.
Embodiment C-11
Use the sputtering target 5 and 6 of preparation in Embodiment C-10 to make optical record medium respectively.
Be formed with thereon on the polycarbonate substrate of guide groove of depth of groove 50nm and track pitch 0.44 μ m, thickness is the ZnS-SiO of 50nm
2The BiFeO layer of layer and thickness 15nm is arranged with laminate structure with this order by sputter; containing the pigment represented by Chemical formula 1 or the organic material layer of dyestuff is formed on the BiFeO layer so that mean thickness is about 30nm by spin coating; thickness is that the reflecting layer of being made by Ag of 150nm is arranged on this organic-material layer by sputter; then the protective layer of being made by ultraviolet curable resin of the about 5 μ m of thickness further is arranged on the reflecting layer by spin coating, obtains repeatedly reading ﹠ recording medium of write-once thus.The material that pigment of being represented by Chemical formula 1 or dyestuff typically are used for common DVD ± R, and this material has respectively in the medium and small absorption of blueness-optical maser wavelength.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths 3T=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, obtain excellent jitter value.Particularly, the optical record medium that uses target 5 at recording power as having jitter value 8.4% under the 5.0mW, the optical record medium of use target 6 has jitter value 8.2% under recording power 5.0mW and this optical record medium both has obtained excellent record performance.
Even when recording power exceeds optimal recording power, can realize having the Write-once-read-many optical recording medium of high modulated amplitude and wide region recording power surplus, and the reproduction of the signal level of recording section or RF level there is not big change yet.
Embodiment C-12
To obtain sputtering target 7 with Embodiment C-1 and identical mode, condition is to mix Bi
2O
3And Fe
2O
3Powder makes that Bi is 10: 5 to the atomic ratio of Fe.The tamped density of this sputtering target is 71%.
Measure the X-ray diffraction pattern of this sputtering target.Measuring condition is as shown in table 3.Figure 12 shows measuring result.
Be the diffraction peak position of determining in measurement, to obtain, those peak contrasts of this diffraction peak position and known substance.The figure that the figure that is labeled as (a) represents the diffraction pattern of target 7 and is marked with (b) represents Bi
36Fe
2O
57The diffraction pattern of given data.Be marked with the BiFeO that illustrates of (c)
3Given data and be marked with the Fe that illustrates of (d)
2O
3Given data.Maximum peak is corresponding to Bi
36Fe
2O
57The peak, and this shows that this compound is a main component.
Embodiment C-13
The sputtering target that use prepares in Embodiment C-12 is made optical record medium.
Be formed with thereon on the polycarbonate substrate of guide groove of depth of groove 21nm and track pitch 0.44 μ m, thickness is the BiFeO layer of 5nm, the ZnS-SiO of thickness 14nm
2Layer and thickness are that the reflecting layer of being made by Ag of 100nm is arranged with the stratiform result with this order by sputter.On sputtering target, the protective layer of being made by ultraviolet curable resin by the about 5 μ m of spin coating layout thickness is to obtain repeatedly reading ﹠ recording medium of write-once.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths 3T=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, under recording power 10.1mW, obtain excellent jitter value 6.2%, and realize excellent record performance by this Write-once-read-many optical recording medium.
Embodiment C-14
Obtain sputtering target 8 in the mode identical with Embodiment C-1, condition is to mix Bi
2O
3Make that with the Fe powder Bi is 35: 5 to the atomic ratio of Fe.The tamped density of this sputtering target is 69%.
Measure the X-ray diffraction pattern of sputtering target, observe very little Bi and Fe peak, and show corresponding to Bi
25FeO
40Compound or corresponding to Bi
36Fe
2O
57Compound be main component.
Embodiment C-15
The sputtering target that use prepares in Embodiment C-14 is made optical record medium.
Be formed with thereon on the polycarbonate substrate of guide groove of depth of groove 50nm and track pitch 0.44 μ m, thickness is the ZnS-SiO of 20nm
2The BiFeO layer of layer and thickness 13nm is arranged with laminate structure with this order by sputter.Being to introduce oxygen 2% time to form this BiFeO layer with respect to the Ar flow velocity simultaneously.On this BiFeO layer, forming thickness is the ZnS-SiO of 20nm
2The layer and by sputtering at ZnS-SiO
2Form thickness on the layer and be the Al-alloy reflecting layer of 100nm and the protective layer of making by ultraviolet curable resin by being spin-coated on the Al-alloy reflecting layer further about 5 μ m of layout thickness to obtain Write-once-read-many optical recording medium.
Use under wavelength 405nm under the following conditions by PULSTEC INDUSTRIAL CO., LTD. makes, and to have numerical aperture be that 0.65 the DDU-1000 of disc evaluation system carries out binary recording to this optical record medium.
＜record condition 〉
Modulating mode: 8-16 modulation
Registration line density: 1T=0.0917 μ m
The shortest mark lengths 3T=0.275 μ m
Line speed record: 6.0m/s
Wave shape equalization: normal state equalizer
As a result, be to obtain excellent jitter value 7.6% under the 9.0mW at recording power, and realize excellent record performance by this Write-once-read-many optical recording medium.
Even when recording power exceeds optimal recording power, can obtain the Write-once-read-many optical recording medium of high modulated amplitude and broad recording power surplus, and the reproduction of signal level or RF level there is not big change yet.
Embodiment C-16
For Bi
10Fe
5O
xSputtering target, make its four targets in an identical manner.Measure the X-ray diffraction pattern of these sputtering targets.Table 4 illustrates these Bi that detect as measuring result
10Fe
5O
xThe diffraction peak 2 θ values of target.The target that has this peak at 2 θ angles as shown in table 4 can provide the example as sputtering target of the present invention.
Table 4
| |
|
|
|
| 21.34 | 21.40 | 21.32 | 21.32 |
| 22.42 | 22.50 | 22.38 | 22.40 |
| 24.72 | 24.80 | 24.66 | 24.70 |
| 27.68 | 27.76 | 37.64 | 27.66 |
| 30.38 | 28.98 | 28.18 | 28.86 |
| |
|
|
|
| 32.08 | 30.46 | 28.84 | 30.36 |
| 32.88 | 32.16 | 30.34 | 32.06 |
| 35.26 | 32.96 | 32.04 | 32.86 |
| 37.46 | 35.30 | 32.84 | 35.22 |
| 38.94 | 37.52 | 35.20 | 35.64 |
| 39.52 | 39.04 | 35.68 | 37.44 |
| 41.58 | 39.58 | 37.42 | 38.94 |
| 43.50 | 41.64 | 38.92 | 39.48 |
| 45.38 | 43.58 | 39.46 | 41.56 |
| 45.76 | 45.46 | 41.54 | 43.50 |
| 48.98 | 45.84 | 43.48 | 45.38 |
| 51.30 | 49.02 | 45.34 | 45.74 |
| 51.74 | 51.40 | 45.74 | 46.96 |
| 52.34 | 51.82 | 48.92 | 48.92 |
| 53.98 | 52.42 | 51.28 | 51.30 |
| 55.58 | 54.06 | 51.72 | 51.74 |
| 56.34 | 55.66 | 52.30 | 52.32 |
| 56.96 | 56.44 | 53.94 | 53.96 |
| 58.72 | 57.16 | 55.54 | 55.58 |
| 58.82 | 56.32 | 56.34 | |
| 57.10 | 57.10 | ||
| 58.68 | 58.68 |
Claims (11)
1. sputtering target, it comprises: Bi, Fe and O, wherein the atomic ratio of Bi and Fe satisfies the requirement of Bi/Fe 〉=0.8.
2. according to the sputtering target of claim 1, wherein this sputtering target is made up of Bi, Fe and O.
3. according to each sputtering target among the claim 1-2, wherein this sputtering target is used to form the recording layer that is used for optical record medium, wherein writes down and reproduces with wavelength and carry out at 550nm or littler laser beam.
4. according to each sputtering target among the claim 1-3, wherein this sputtering target comprises Bi oxide compound and Fe oxide compound, or comprises the composite oxides of Bi and Fe.
5. according to the sputtering target of claim 4, wherein this sputtering target comprises the composite oxides of Bi and Fe and further comprises one or more that are selected from Bi oxide compound and Fe oxide compound.
6. according to the sputtering target of claim 1, wherein this sputtering target comprises one or more of the composite oxides that are selected from Bi oxide compound, Fe oxide compound and Bi and Fe, and this oxide compound is the oxide compound with the oxygen in a small amount of comparing with stoichiometric composition.
7. according to each sputtering target among the claim 1-6, wherein this sputtering target comprises and is selected from BiFeO
3, Bi
25FeO
40, and Bi
36Fe
2O
57One or more.
8. according to each sputtering target among the claim 1-7, wherein this sputtering target comprises Bi
2O
3And/or Fe
2O
3
9. according to each sputtering target among the claim 1-8, wherein this sputtering target does not comprise Bi
2Fe
4O
9
10. according to each sputtering target among the claim 1-9, wherein the content of Co, Ca and Cr is less than the detectability of inductively coupled plasma emission spectrometric method.
11. according to each sputtering target among the claim 1-10, wherein the tamped density that has of this sputtering target is 65%-96%.
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP252389/04 | 2004-08-31 | ||
| JP2004252389 | 2004-08-31 | ||
| JP2004273774 | 2004-09-21 | ||
| JP273774/04 | 2004-09-21 | ||
| JP2005064328A JP4541192B2 (en) | 2005-03-08 | 2005-03-08 | Write-once optical recording medium |
| JP064328/05 | 2005-03-08 | ||
| JP2005113466A JP4865249B2 (en) | 2004-08-31 | 2005-04-11 | Sputtering target, manufacturing method thereof, and optical recording medium |
| JP113466/05 | 2005-04-11 |
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| CNB200580001454XA Division CN100450783C (en) | 2004-08-31 | 2005-08-30 | Write-onece-read-many optical recording medium and its sputtering target |
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| US8264940B2 (en) * | 2007-12-06 | 2012-09-11 | Panasonic Corporation | Recording/reproduction device, recording/reproduction method, and information recording medium |
| WO2011062021A1 (en) * | 2009-11-20 | 2011-05-26 | Jx日鉱日石金属株式会社 | Bi-ge-o sintered body sputtering target, method for producing same, and optical recording medium |
| US8597774B2 (en) * | 2010-07-15 | 2013-12-03 | Toyo Seikan Kaisha, Ltd. | Laser-marking film |
| CN108754431B (en) * | 2018-06-01 | 2020-09-18 | 中国科学院深圳先进技术研究院 | Single-phase multiferroic thin film and preparation method and application thereof |
| TWI727322B (en) * | 2018-08-09 | 2021-05-11 | 日商Ｊｘ金屬股份有限公司 | Sputtering target and magnetic film |
| CN114038611A (en) * | 2021-11-01 | 2022-02-11 | 吉林大学 | Far infrared transparent conductive film material and preparation method thereof |
| CN114773061B (en) * | 2022-05-06 | 2023-02-24 | 中国科学院精密测量科学与技术创新研究院 | Preparation method of metal metaborate laser sputtering target material |
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| JPS59185048A (en) * | 1983-04-01 | 1984-10-20 | Matsushita Electric Ind Co Ltd | Member for recording optical information and its recording method |
| JPS6394444A (en) * | 1986-10-07 | 1988-04-25 | Daicel Chem Ind Ltd | Novel optical recording medium |
| JPH1092027A (en) * | 1996-09-18 | 1998-04-10 | Nippon Hoso Kyokai <Nhk> | Optical recording medium, its manufacture as well as recording method for optical recording medium |
| JP2000163804A (en) * | 1998-11-24 | 2000-06-16 | Ricoh Co Ltd | Draw type optical recording medium |
| JP4307767B2 (en) * | 2001-03-07 | 2009-08-05 | 株式会社リコー | Optical information recording medium and information recording method for the medium |
| JP2003203383A (en) * | 2001-12-28 | 2003-07-18 | Tdk Corp | Write-once/read-many type optical recording medium and optically recording method |
| JP2004284018A (en) * | 2002-03-08 | 2004-10-14 | Ricoh Co Ltd | Optical recording medium |
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