• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    PURPOSE: A re-recordable and phase-transition type optical recording composition and a re-recordable and phase-transition type disc are provided to realize the phase transition between a crystal state and an amorphous state after radiation of signal laser beams, thereby achieving the recording, deleting, reproducing and over-writing. CONSTITUTION: A re-recordable and phase-transition type optical recording composition includes £Tex(Gey(Bi1-βSbβ)z|100-aXa, wherein x is boron or carbon, x=47-60at.%, y=12-48at.%, z=5-41at.%, x+y+z=100at.%, β=0.1-0.9, a=0.05-4at.%. The re-recordable and phase-transition type disc includes a re-recordable and phase-transition type optical information recording layer having the composition.
    公开号:KR20020059162A
    申请号:KR1020010000225
    申请日:2001-01-03
    公开日:2002-07-12
    发明作者:친성쑨；이첸밍
    申请人:리우 챠오 시우안；내셔널 사이언스 카운실；
    IPC主号:
    专利说明:

    REWRITABLE PHASE-CHANGE OPTICAL RECORDING COMPOSITION AND REWRITABLE PHASE-CHANGE OPTICAL DISK}
    [15] TECHNICAL FIELD The present invention relates to an optical information recording medium, and in particular to a rewritable optical recording material which changes in phase between a crystalline state and an amorphous state after irradiation of a signal laser beam to enable recording, erasing, reproduction and over-writing. And a rewritable optical recording disc accordingly.
    [16] The erasable phase change type optical disc makes it possible to perform recording and erasing functions by using a phase change between the crystalline state and the amorphous state of the recording layer. In order to facilitate the understanding of the present invention, the principle of operation of an erasable phase change optical disc is described in connection with the prior art.
    [17] The conventional erasable phase change type optical disc shown in FIG. 1 includes a phase change type recording layer 2 sandwiched between an upper dielectric layer and a lower dielectric layer 3 on a substrate 1, and a reflective layer 4 on an upper dielectric layer. And a plastic protective layer 5 on the reflective layer 4. Suitable materials for the dielectric layer 3 are SiO 2 -ZnS. The substrate 1 may be formed of polymethyl methalcrylate, polycarbonate, or glass. Suitable materials for forming the reflective layer 4 are Au, Cu, Al, Ni, Cr, Pt, Pd and their alloys.
    [18] Currently erasable phase change type optical discs use a chalcogenide material based on Te or Se as the recording layer. When the area of the recording layer is rapidly heated to the molten state after irradiation of a focused laser beam with high power short pulse modulation, it is electrically conductive and cooled in an amorphous state by adjacent layers (e.g., dielectric and reflective layers). , A recording mask is formed. The amorphous recording mask has a reflectance lower than that of the blank crystal region (in some special alloys, the reflectivity of the amorphous recording mask is higher), and the difference in reflectance is used for signal reproduction. A laser beam with a long pulse of medium power is used to erase the recording mask and restores the blank crystal region to the temperature between the melting point and the crystal point by heating.
    [19] Chalcogenide materials were first used as phase change recording layers by SR Ovsinsky, et al. In US Pat. No. 3,530,441. In this US patent, thin films of Te 85 Ge 15 and Te 81 Ge 15 S 2 Sb 2 generate reversible phase transitions upon irradiation of high energy densities such as laser beams. Since then, most research work has focused on chalcogenide materials such as GeTe, InSe, InSeTl, InSeTlCo, GeSbTe, GeTeSn, GeTeAs, GeTeSnAu, InTe, InSeTe, InSbTe, and SbSeTe. Of these materials, the GeSbTe alloy series developed by Matsushita Electric Industrial Co., Ltd. of Japan, US Pat. Nos. 5,233,599, 5,278,011 and 5,294,523 are the most promising materials. The details of this patent are incorporated by reference throughout this specification.
    [20] However, the phase change materials present two crystal phases in crystallization, namely, a low temperature face-centered cubic (FCC) phase and a high temperature hexagonal close-packed lattice (HCP) phase. Has the disadvantage. The transition between FCC and HCP greatly reduces the reliability of rewritable phase change optical disks after a long service period and reduces the possible number of write-erase cycles.
    [1] 1 is a cross-sectional view showing the structure of a conventional erasable phase change type optical disk.
    [2] 2 is a block diagram showing a wide range of the rewritable phase change type optical information recording composition, Te- (Ge, Bi, Sb) -X according to the present invention, wherein X = B or C, and X is 0.05 to 5 at Has.%
    [3] Figure 3 shows the X-ray diffraction spectrum of the crystal layer of the control composition, Te (Ge 0.8 Sb 0.2 ) after annealing.
    [4] FIG. 4 is a schematic diagram of reflectance versus wavelength in the visible range showing reflectance of the crystalline layer (R C ) and amorphous layer (R A ) of the control composition Te 51.4 Ge 36.1 Sb 12.5 .
    [5] Figure 5 shows the X-ray diffraction spectrum of the crystal layers of the four compositions prepared according to Example 1 of the present invention after heat treatment for 10 minutes at 250 ℃, four compositions (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) Has the formula 1-a B a , where a is 0, 0.89, 1.54 and 1.86 at.%, Designated B0, B1, B2 and B3, respectively.
    [6] FIG. 6 is a schematic diagram of reflectance versus wavelength in a visible light range showing reflectances of a crystalline layer (R C ) and an amorphous layer (R A ) among four compositions prepared according to Example 1 of the present invention.
    [7] 7 is a schematic diagram of light gradation versus wavelength in the visible range showing the optical contrasts of the four compositions prepared according to Example 1 of the present invention and the control composition (designated A) used in FIG. 4.
    [8] Figure 8a shows the X-ray diffraction spectrum of the crystal layers of the four compositions prepared according to Example 2 of the present invention after the heat treatment for 10 minutes at 180 ℃, four compositions (Te 54.5 Ge 22.0 Bi 6.5 Sb 17.0 ) Has the formula 1-a B a , where a is 0, 0.74, 1.27 and 1.85 at.%, Designated C0, C1, C2 and C3, respectively.
    [9] FIG. 8B shows the X-ray diffraction spectra of the crystalline layers of the four compositions prepared according to Example 2 of the present invention after heat treatment at 300 ° C. for 10 minutes.
    [10] 9 is a schematic diagram of reflectance versus wavelength in the visible light range showing reflectances of the crystalline layer (R C ) and the amorphous layer (R A ) of four compositions prepared according to Example 2 of the present invention.
    [11] FIG. 10 is a schematic diagram of light gradation versus wavelength in the visible light range showing light gradation among four compositions prepared according to Example 2 of the present invention.
    [12] FIG. 11 is a schematic diagram showing dynamic erasing and recording characteristics of two phase change type optical discs manufactured using the compositions B0 and B1 of Example 1 of the present invention.
    [13] 12 is a schematic diagram showing dynamic erasing and recording characteristics of two phase change type optical discs manufactured using the compositions C0 and C1 of Example 2 of the present invention.
    [14] FIG. 13 is a block diagram showing a preferred range of a rewritable phase change type optical information recording composition, Te- (Ge, Bi, Sb) -X according to the present invention, wherein X = B or C and X is 0.05 to 4 at Has.%
    [21] The present invention discloses a new five-element alloy, ie Te- (Ge, Bi, Sb) -X, X = B or C, for use as a phase change type optical recording material showing improvements in the prior art. Conventional refinements of the five-element alloy according to the present invention are well suited for use as rewritable phase change optical recording materials, including excellent high crystal speeds and high light gradations between amorphous and crystalline states within the visible range.
    [22] The rewritable phase change type optical recording composition designed according to the present invention is intended to simultaneously replace a portion of Ge with Bi and Sb in a Te-Ge binary system and to administer a small amount of atomic boron or carbon having the formula .
    [23] [Te (Ge 1-α M α ) γ ] 100-a X a
    [24] Where M = Bi 1-β Sb β , X = B or C, more precisely in atomic percentage (at.%).
    [25] [Te x (Ge y (Bi 1-β Sb β ) z ] 100-a X a
    [26] Here, x = 47-60at.%, Y = 12-48at.%, Z = 5-41at.%, X + y + z = 100at.%, Β = 0.1-0.9, a = 0.05-4at.%.
    [27] The rewritable phase change type optical recording composition according to the present invention can be classified into two groups according to the value of y, and the composition of the first group has y = 28 to 48at.%, Z = 5 to 25at.%, Β = 0.1 to 0.9, a = 0.5 to 3 at.%, And the composition of the second group is y = 12 to 28 at.%, Z = 12 to 41 at.%, Β = 0.1 to 0.9, and a = 0.5 to 3 at.%. .
    [28] Preferably, the Group 1 composition has a light gradation greater than 30% in the visible range between the amorphous and crystalline states.
    [29] Preferably, the Group 1 composition has a crystal temperature ranging from 180 to 210 ° C.
    [30] Preferably, the Group 1 composition has only the FCC phase at the crystalline state and at temperatures below 300 ° C.
    [31] Preferably, the Group 1 composition has a crystal activation energy ranging from 1.5 to 3.5 eV at a crystal temperature.
    [32] Preferably, the Group 2 composition has a light gradation greater than 20% in the visible range between the amorphous and crystalline states.
    [33] Preferably, the Group 2 composition has a crystal temperature ranging from 140 to 180 ° C.
    [34] Preferably, the Group 2 composition has only the FCC phase at temperatures below 250 ° C.
    [35] Preferably, the Group 2 composition has a crystal activation energy ranging from 1.5 to 3.5 eV at a crystal temperature.
    [36] Preferably, the Group 1 composition has the following composition.
    [37] (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 99.11 B 0.89 , (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 98.46 B 1.54 , (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 98.14 B 1.86 , or (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 99.01 C 0.99 .
    [38] The present invention also provides a rewritable phase change type optical disc having a substrate and a rewritable phase change type optical recording layer applied on the substrate, wherein the rewritable phase change type optical recording layer has the rewritable phase change type of the present invention. It has a composition of a fluorescent recording composition.
    [39] (1) alloy design
    [40] The alloy design according to the invention is based on the binary alloy TeGe. TeGe has a disadvantage of high melting point (725 ° C.), crystal temperature, crystal activation energy barrier, and a second crystal phase (HCP) at high temperatures. In order to control the crystal temperature and crystal activation energy, we use Group VA elements to partially replace the expensive and high melting point Ge in the TeGe alloy. More specifically, Bi and Sb are added to lower the crystal temperature and crystal activation energy and to facilitate the manufacture of the designed alloy. On the other hand, smaller atoms of IIIA or IVA, such as boron or carbon, are injected in small amounts into the interstices of the lattice to stabilize the crystalline phase at high temperatures of the designed alloy layer and maintain the single crystal phase at high temperatures. The design alloy according to the invention consists of a composition of Te (Ge, Bi, Sb), γ is more suitable between 0.67 and 1.50 to maintain the FCC crystal phase. The amount of B or C added is limited to the range of 0.05 to 5 at.% To prevent precipitation of B, C or other compounds. As a result, the ratio of Ge: Bi: Sb is variable. The design alloy according to the invention has a composition range obtained by points I, II, III and IV as shown in figure 2 and can be represented by the following formula:
    [41] [Te (Ge 1-α M α ) γ ] 100-α X α
    [42] Where M = Bi 1-β Sb β ; X = B or C; 0.67 <γ <1.50; 0.08 <α <0.92; 0.05 < β &lt;0.95; And 0.05 < a < 5. The formula can be more clearly presented in atomic percentage (at.%) As follows.
    [43] [Te χ Ge ｙ (Bi 1-β Sb β ) z ] 100-a X a
    [44] Where x = 47 to 60 (at.%); y = 12 to 48 (at.%); z = 5 to 41 (at.%), x + y + z = 100 (at.%).
    [45] (2) Manufacture and Target of Designed Alloys
    [46] Any method known in the art can be used to produce targets for forming layers of designed alloys and designed alloys according to the invention. The examples below are merely illustrative and do not in any way limit the rest other than those disclosed. Te- (Ge, Bi, Sb) alloy ingots or targets seal high purity Te, Ge, bi, and Sb in a quartz tube at a predetermined weight ratio, and at 800 to 1000 ° C while rotating and shaking the quartz tube. It is prepared by heating to melt the elements, maintaining the heating temperature for one hour for small diameter quartz tubes and three hours for large diameter quartz tubes, and cooling the quartz tube.
    [47] The ingot obtained after cooling was again heated to a temperature 20 ° C. below the melting point of the alloy ingot for one week in order to perform a homogenization heat treatment. The melting point of the alloy ingot has already been determined by DSC analysis. The composition of the homogenized alloy ingot was analyzed before being used as a target with a thickness of 5 mm.
    [48] The addition of boron or carbon was performed by adding high purity boron or carbon while melting the Te- (Ge, Bi, Sb) alloy ingot, or by melting GeB or GeC and the Te- (Ge, Bi, Sb) alloy ingot together. . Alternatively, the composition target for applying one layer of the 5-element alloy, Te- (Ge, Bi, Sb) -X (X = B or C), may contain a portion of high purity boron or carbon as Te- (Ge , Bi, Sb) were prepared by adhering to a target surface at a predetermined area ratio.
    [49] (3) application of layers
    [50] Any coating method known in the prior art can be used for forming the recording layer of the optical disk according to the present invention, which is applied in vacuum, such as thermal evaporation and E-beam evaporation. Evaporation method of; Sputtering methods such as DC, RF, magnetron, symmetrical and asymmetrical sputtering, and the like; And vacuum ion plating, including but not limited to.
    [51] In Examples 1 and 2 according to the present invention, a recording layer of a phase change type optical disk, Te- (Ge, Bi, Si) -X (X = B or C), was prepared by RF magnetron sputtering with a composition target without heating the substrate. It was formed by performing (magnetron sputtering). The control example used Te (Ge 0.8 Bi 0.1 Sb 0.1 ) target. Example 1 used a composition target formed by attaching thin boron or carbon pieces of different sizes to the surface of a Te (Ge 0.8 Bi 0.1 Sb 0.1 ) target, and Example 2 used Te (Ge 0.5 Bi 0.125 Sb 0.375 ) 0.8 as the main target. Used as a target. Two different substrates were used, one was glass (Dow Corning # 7059 glass) and the other was polycarbonate (PC). The recording layer was applied directly to the substrate with a thickness of 100 nm.
    [52] The layer to which arsenic was applied was amorphous, and in the following example, crystallization annealing heat treatment was performed to convert the layer to a crystalline state.
    [53] Samples were heated in the furnace for 10 minutes at a predetermined temperature in the range of 180-350 ° C. The furnace maintained a rich argon pressure of about 1 atm.
    [54] (4) analysis
    [55] Analysis was performed on both the arsenic coating layer and the crystallizaton-annealed layer.
    [56] Inductively coupled plasma-atomic emission spectrometer (ICP-AES) was used to quantitatively determine the composition of the applied layer; A low angle X-raydiffractometer was used to analyze the structure of the applied layers; And a photospectrometer was used to measure the reflectance (R) of the applied layers. A differential scanning calorimeter (DSC) was used to perform thermal analysis after the arsenic coated layer was removed from the substrate, and the crystal temperature of the amorphous layer was then determined. The crystal activation energy was calculated from the shift of the heat dissipation peak of the DSC curve determined from different heating rates by the method according to Kissinger's plot.
    [57] (5) analysis results
    [58] The compositions of the applied layers of Examples 1 and 2 determined by ICP-AES quantitative analysis are shown in Table 1 together with the compositions of the control examples.
    [59]
    [60] The arsenic-coated layer of the control example was in an amorphous state, but was transformed into a crystalline state after heat treatment at 250 ° C. for 10 minutes as shown in FIG. 3. The crystal structure was identified as a single phase of a face centered cube (FCC) structure with a lattice constant of 0.5980 nm.
    [61] 4 shows the reflectances of the amorphous layer R A and the crystal layer R c of the control example in the visible light range (380 nm to 830 nm). The reflectivity of the amorphous and crystalline states shows high values, and R A ranges from 39% to 830nm to 30% at 830nm, while R c ranges from 55-59% within the measured wavelength range.
    [62] The applied layer of the control example was analyzed by a differential stretching calorimeter at a heating rate of 10 ° C./min. One heat dissipation peak was found at 227 ° C., ie the crystal temperature. Crystal activation energy was calculated to be 4.03 eV.
    [63] Example 1 All of the arsenic-coated layers of the composition were in an amorphous state, and after being annealed at 250 ° C. for 10 minutes as shown in FIG. The crystal structure of the composition of Example 1 was identified as a single phase of a face centered cube (FCC) structure, and its lattice constant increased with increasing content of boron. Similar phenomena were observed in the crystalline layer containing carbon atoms, pointing out that boron or carbon atoms enter the interstices of the matrix lattice, increasing the lattice constant.
    [64] 6 shows reflectances of the amorphous layer (R A ) and the crystal layer (R c ) of the B0-B3 composition of Example 1 in the visible range. It can be seen from FIG. 6 that the reflectance of the crystal layer R c increases significantly as the atoms generated are added; However, the increase in amorphous layer R A is not significant. Among them, the B1 composition has the largest change in reflectance. The amorphous and crystalline layers of the B4 composition containing carbon atoms have a greater reflectance than the B0 composition containing no carbon atoms.
    [65] FIG. 7 is a schematic of light gradation versus wavelength, showing the light gradation of the control example (designated as A in Table 1) and the four compositions of Example 1 in the visible range (designated B0 to B3 in Table 1). . Light gradation is defined as follows:
    [66] Light gradation = (R c -R A ) / R C = ΔR / R C
    [67] Optical gradation is closely related to the readability of phase-changeable optical discs. Higher optical gradation means a large difference in reflectance between the amorphous and crystalline states, and as the recording mark size decreases, a higher carrier-to-noise ratio carrier-to-noise ratio (CNR) is obtained. The control composition (A) has a relatively high light gradation, for example from 31% at 380 nm to 49% at 830 nm. The light gradation of the B0 composition is about 3-4% lower than the light gradation of the control composition (A) in the same wavelength range, indicating that adding Bi will lower the light gradation. On the other hand, the compositions of B1 to B4 all have a higher light gray level than the B0 composition, and show that light gray occurs in the composition to which bismuth was added. Table 2 shows the light gradations of the control composition (A) and the B0-B4 compositions at wavelengths selected from 780 nm, 650 nm, 450 nm and 380 nm, wherein the light gradations of the 5-element compositions B1 to B4 are at least 30%.
    [68]
    [69] The heat radiation peak in the DSC curve of the arsenic coating layer of the control composition (A) of the compositions B0 to B3 of Example 1 was observed as the crystal temperature of the composition. Table 3 shows the crystal temperature and crystal activation energy of the control composition (A) of the B0 to B4 compositions of Example 1. When Bi was mixed in the control composition, the crystal temperature and crystal activation energy were lowered, and in the case of the B1 composition a decrease in crystal temperature and crystal activation energy was observed with small doping of B. Such effects were also observed when a small amount of carbon was doped and it was found that the addition of carbon atoms was effective in lowering the crystal temperature and crystal activation energy. It is known that the lower the crystal activation energy, the faster the crystal velocity.
    [70]
    [71] In view of the analytical results of Comparative Example and Example 1, it can be concluded that the addition of Bi and Sb to the TeGe alloy can effectively lower the crystal temperature and the crystal activation energy at low light gradations. However, mixing of boron atoms or carbon atoms can lead to loss of light gradation while maintaining good crystalline properties.
    [72] Example 2 The arsenic coated layers of the composition were in an amorphous state and were converted to a crystalline state after heat treatment at 180 ° C. for 10 minutes as shown in FIG. 8A. The crystal structure of the composition of Example 2 was identified as the FCC structure of the single phase, where the lattice constant increases with increasing boron content and the boron atoms increase the lattice constant by introducing the matrix lattice in an interstitial atoms manner. It was pointed out that. When the heat treatment temperature was increased to 300 ° C., the crystal structure of the Co composition changed to the single phase HCP structure. However, the crystal structure of the C1 to C3 composition layers remained FCC structure. Therefore, the addition of boron atoms has the effect of stabilizing the FCC structure. Furthermore, as shown in FIGS. 8A and 8B, the widths of the diffraction peaks of the C1 to C3 composition layers heat treated at 300 ° C. did not change compared to the widths of the diffraction peaks of the C1 to C3 composition layers heat treated at 180 ° C. FIG. In the case of the C0 composition layer, the width becomes quite narrow. The large width of the diffraction peak means a smaller particle size in the crystal layer, whereby the noise value due to optical anisotropy decreases as the optical disc is read, and the boundary of the recording area is formed more clearly. As a result, the addition of boron atoms suppresses the growth of crystal grains and reduces the particle size. Similar phenomena were observed in the crystal layer containing carbon atoms (C4 composition), and the crystal structure was a single phase of the FCC structure after 180 ° C. heat treatment and 300 ° C. heat treatment.
    [73] 9 shows reflectances of the crystalline layer (R C ) and the amorphous layer (R A ) in the C0 to C3 compositions according to Example 2 of the present invention within the visible range. The reflectance of the crystal layer (R C ) and the reflectance of the amorphous (R A ) increase in the largest region in the visible range as the boron atoms are added. FIG. 10 shows the light gradations of the four compositions (C0 to C3, Table 1) according to Example 2 of the present invention within the visible light range, which is lower than the light gradations of Example 1. FIG.
    [74] Taking the C0 composition as an example, the average light gradation within the range of 400 nm to 800 nm is 17% and lower at wavelength <400 nm. However, 5-element compositions (C1 to C3) have an average light gradation in the visible light range higher than 20% and become higher in the short wavelength range as the boron content increases, for example, the C2 composition is 23% at 450 nm. It has a light gradation of. As for the carbon-containing layer (C4 composition), the average light gradation is 19% within 400 nm to 800 nm. This indicates that the addition of boron or carbon atoms to the C0 composition can effectively increase the light gradation as well as the stability of the crystalline phase. Table 4 shows the light gradations of the C0 to C4 compositions at wavelengths of 780 nm, 650 nm, 450 nm and 380 nm.
    [75]
    [76] The arsenic coating layer of the C0 to C3 compositions of Example 2 shows two heat dissipation peaks in the DSC curve. As a result of the change from the amorphous state to the FCC structure, the first heat dissipation peak at about 160 ° C. is taken as the crystal temperature of the composition. The second heat dissipation peak is caused by the crystal phase transition from FCC to HCP occurring at 280 ° C ambient temperature. The addition of boron can reduce the crystal temperature by about 1 to 2 ° C. while increasing the transition temperature from the FCC to HCP (about 270 to 300 ° C.). The crystal activation energy of C0 to C3 corresponding to FCC transformation in amorphous phase remains constant at 2.9 to 3.0 eV as the boron content increases, while the activation energy corresponding to the transition from FCC to HCP increases. Thus, the addition of boron has the effect of stabilizing the FCC structure. The addition of carbon atoms is also effective in stabilizing the FCC structure. Table 5 shows the results of the thermal analysis.
    [77]
    [78] Several phase-changeable optical discs in the format of 2.6 GB Digital Versatile Disk-Random Access Memory (DVD-RAM) were made using one of B0, B1, C0 and C1 as the composition of the recording layer. The optical disc has four layers applied to a 0.6 mm PC substrate, the four layers being the lower dielectric layer of ZnS-SiO 2 (150 nm), the recording layer (20 nm), the upper dielectric layer of ZnS-SiO 2 (15 nm), and Al (80 nm) is a reflective layer. Finally, the blank substrate was bonded to the coated substrate to complete the manufacture of the optical disc. The recording-erasing characteristics were evaluated by an optical head with a laser wavelength of 638 nm and a dynamic tester with an aperture ratio of 0.6. Modulated signals (8, 16) and mark edge writing methods have been used for carrier to noise ratio (CNR) measurements. In recording at a linear speed of 6 m / s, a 3T display length with a frequency of 4.87 MHz was set. DC erase at the write mark of the optimal write power was applied for the erase ratio (ER) measurement. The cancellation ratio is defined as the CNR difference between the recorded signal and the canceled signal.
    [79] Fig. 11 shows CNR and ER, respectively, as functions of write power and erase power of two phase change type optical disks manufactured using the compositions B0 and B1 of Example 1 of the present invention as recording layers. The optimum erase power is 6 mW with ER of 32 and 33 dB, respectively, for the recording layers B0 and B1. The optimal write power is 14mW with a CNR of 54dB in both recording layers B0 and B1. The erase power and the write power are almost the same for the boron-added recording layer and the boron-added recording layer, while the ER and CNR values increase slightly with the addition of boron. The cyclicability test shows that after 10 5 cycles of writing and erasing, the CNRs of the recording layers BO and B1 are reduced to 48 and 49 dB, respectively, so that both recording layers have good overwriting performance.
    [80] Fig. 12 shows CNR and ER of two phase change type optical discs produced using the compositions C0 and C1 of Example 2 of the present invention as recording layers. The optimal erase power is 5 mW with an ER of 20 for both recording layers C0 and C1. The optimal write power is 12 mW with CNRs of 52 and 51 dB in the recording layers C0 and C1, respectively. The erase power and the write power are almost the same for the boron-added recording layer and the boron-added recording layer, while the ER and CNR values decrease slightly with the addition of boron. Compared with the recording layers B0 and B1, the recording layers C0 and C1 have low erase and write power, and show a decrease of about 12 dB in ER. The periodicity test shows that after 10 5 cycles of writing and erasing, both CNRs of the recording layers CO and C1 are reduced to about 48 dB, so that both recording layers have good overwriting performance.
    [81] Another analysis of the designed alloy of the present invention confirmed the following facts.
    [82] a) The amount of Ge is preferably higher than 12 at.%, which has a sufficiently high melting point and a suitable crystal temperature;
    [83] b) The sum of Bi and Su amounts is preferably higher than 5 at.%, providing a significant improvement in lowering the crystal temperature and activation energy;
    [84] c) The amount of Te is preferably in the range of 47 at.% to 60 at.% to avoid undesirable phases;
    [85] d) The amount of boron or carbon is preferably lower than 4 at.% to avoid the occurrence of boron compounds or carbon compounds.
    [86] Thus, the preferred 5-element alloy according to the present invention has a composition in the region surrounded by points A to D as shown in FIG. Moreover, the preferred 5-element alloy having the composition in the ABCD region is separated into two groups by the line EF, wherein the group 1 composition comprising the composition B0 has properties close to those of the compositions of B1 to B4 of Example 1 , Group 2 composition will have characteristics close to the composition of C1 to C4 of Example 2.
    [87] Although the invention has been described with reference to the specifics of some embodiments, it is not intended to be considered as a limitation on the scope of the invention except as included in the accompanying claims. Various modifications are possible in light of the above disclosure.
    [88] Included in the above.
    权利要求:
    Claims (14)
    [1" claim-type="Currently amended] In a rewritable phase change type optical information recording composition having the formula [Te x (Ge y (Bi 1-β Sb β ) z ] 100-a X a , wherein X is boron or carbon, and x = 47 to 60 atomic percentage. (at.%), y = 12 to 48at.%, z = 5 to 41at.%, x + y + z = 100at.%, β = 0.1 to 0.9, a = 0.05 to 4at.% Possible phase change optical information recording composition.
    [2" claim-type="Currently amended] The rewritable phase change type optical information recording composition according to claim 1, wherein y = 28 to 48 at.%, Z = 5 to 25 at.%, Β = 0.1 to 0.9, and a = 0.5 to 3 at.%.
    [3" claim-type="Currently amended] 3. The rewritable phase change type optical information recording composition according to claim 2, wherein the composition has a light gradation greater than 30% in the visible range between the amorphous state and the crystalline state.
    [4" claim-type="Currently amended] 3. The rewritable phase change type optical information recording composition according to claim 2, wherein the composition has a crystal temperature ranging from 180 to 210 deg.
    [5" claim-type="Currently amended] 3. The rewritable phase change type optical information recording composition according to claim 2, wherein the composition has only a face-centered cubic (FCC) image at a crystalline state and a temperature of 300 ° C or lower.
    [6" claim-type="Currently amended] 3. The rewritable phase change type optical information recording composition according to claim 2, wherein the composition has a crystal activation energy ranging from 1.5 to 3.5 eV at a crystal temperature.
    [7" claim-type="Currently amended] The rewritable phase change type optical information recording composition according to claim 1, wherein y = 12-28 at.%, Z = 12-41 at.%, Β = 0.1-0.9, and a = 0.5-3 at.%.
    [8" claim-type="Currently amended] 8. The rewritable phase change type optical information recording composition according to claim 7, wherein said composition has a light gradation greater than 20% in the visible range between an amorphous state and a crystalline state.
    [9" claim-type="Currently amended] The rewritable phase change type optical information recording composition according to claim 7, wherein the composition has a crystal temperature ranging from 140 ° C to 180 ° C.
    [10" claim-type="Currently amended] 8. The rewritable phase change type optical information recording composition according to claim 7, wherein the composition has only an FCC phase at a crystalline state and a temperature of 250 ° C or lower.
    [11" claim-type="Currently amended] 8. The rewritable phase change type optical information recording composition according to claim 7, wherein the composition has a crystal activation energy ranging from 1.5 to 3.5 eV.
    [12" claim-type="Currently amended] The composition of claim 7 wherein the composition is (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 99.11 B 0.89 , (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 98.46 B 1.54 , (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 98.14 B 1.86 Or (Te 50.6 Ge 37.4 Bi 5.7 Sb 6.3 ) 99.01 C 0.99 .
    [13" claim-type="Currently amended] The composition of claim 7 wherein the composition comprises (Te 54.5 Ge 22.0 Bi 6.5 Sb 17.0 ) 99.26 B 0.74 , (Te 54.5 Ge 22.0 Bi 6.5 Sb 17.0 ) 98.73 B 1.27 , (Te 54.5 Ge 22.0 Bi 6.5 Sb 17.0 ) 98.15 B 1.85 Or (Te 54.5 Ge 22.0 Bi 6.5 Sb 17.0 ) 98.93 C 1.07 .
    [14" claim-type="Currently amended] A rewritable phase change type optical information recording disc having a substrate and a rewritable phase change type optical information recording layer applied on the substrate, wherein the rewritable phase change type optical information recording layer comprises a composition according to any one of claims 1 to 13. And a rewritable phase change type optical disc having:
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    同族专利:
    公开号 | 公开日
    KR100453540B1|2004-10-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2001-01-03|Application filed by 리우 챠오 시우안, 내셔널 사이언스 카운실
    2001-01-03|Priority to KR20010000225A
    2002-07-12|Publication of KR20020059162A
    2004-10-22|Application granted
    2004-10-22|Publication of KR100453540B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR20010000225A|KR100453540B1|2001-01-03|2001-01-03|Rewritable phase-change optical recording composition and rewritable phase-change optical disk|
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