TWI223808B - Phase-change optical recording medium - Google Patents

Abstract

A rewritable optical information recording medium and its recording method are disclosed in the present invention. The optical recording medium contains a substrate and a phase-change layer formed on the substrate. The composition range of the phase-change layer is represented by GexSbyMz, in which x=5 to 25 atomic %, y=70 to 90 atomic %, z=2 to 25 atomic %, x+y+z=100, and M is selected from the family group composed of the following elements: B, O, N, P, Bi, In, Ga, Sn, Pb, Si, Ag, Au, Ti, Zr, Cr, Ni, Hf, V, Nb, Ta, Mn, W, Mo, and Ce. The phase-change layer has a lower crystallization temperature such that it is capable of reducing time required for converting the phase-change layer from amorphous structure into the crystalline structure when using a laser light beam to conduct the wiping process. And, the crystallization speed is then increased. Thus, the invention can be used as the phase-change layer of the new type rewritable optical-information recording medium, and can be used in the application of high-speed rewritable optical-information recording medium.

Description

1223808 V. Description of the invention (1) ^ " " " " A ^-[Technical Field Widely Invented] tThe invention is a rewritable optical information recording medium, especially related to the optical information that can be duplicated Phase change layer of recording medium. [Prior technology] A rewritable phase change optical disc uses the phase change between crystalline and amorphous phases in the recording layer to achieve the purpose of writing and erasing. A rewritable phase change optical disc is made of a chalcogenide material containing a tellurium (Te) or selenium (Se) element as a recording layer material. The material of the recording layer was an amorphous (a in 〇r ph 〇us) structure when it was first formed. The structure of the recording layer formed was changed from an amorphous state to a crystalline state through an initialization step. The condition of the laser beam with a short pulse of high power = the recording layer of the disc, the temperature of the recording layer will instantly rise above the melting point, and after V becomes k, it will be quenched by rapid thermal conduction (quench) into a non-sad σ Have recorded points. After writing, the reflectivity of the amorphous recording point is lower than that of other unrecorded areas in the state of the Japanese. This change in reflectivity can be used as a signal for recording. At that time, the laser beam irradiates the recording point under the conditions of medium power and long pulse, so that the temperature of the recording point is between the melting point and the crystallization temperature, and the recording point is thus: ^ Crystallized 'returns to the state when it was not recorded. The structure of a rewritable phase change disc is shown in Figure 丨. The phase-change e-recording layer (4) is interposed between the upper and lower dielectric layers (5, 3) and is structured on the substrate (2). The dielectric layer is divided into upper and lower layers. The material is wood.

ZnS-SiO2, the base material is PMMA, PC or glass. There is a reflective layer (6) on the upper dielectric reed, and the reflective layer material is Au, Cll, ai, Ni

1223808

Pt, Pd, etc., or an alloy protective layer (7) of the above elements. Resin on the top of the disc "The material is a chalcogenide with amorphous / crystalline two-phase conversion function. 〇 ^ 1〇81 ^ First proposed in the US patent Us Pat. No. m 1 Te8sGei5 and TesiGeiASb2 Below high-energy lasers, reversible phase-change recording materials can be performed, and chalcogenide materials have become the focus of research in Dae. Later phase-change recording materials that have been developed successively belong to chalcogenides, such as GeTe, InSe, Ιη & τι,

InSeTICo, GeTeSb 'GeTeSn, GeTeAs, GeTeSnAu, InTe, I_nSeTe' InSbTe, SbSeTe, etc. Among them, the GeSbTe system developed by the Japanese Matsushita Company attracted the most attention.

GeTe-Sb2Te3 quasi-binary alloy phase diagram was first proposed by N. Kh. Abrikosov et al. In 1965 and published in 12 ¥ · Akad. Nauk SSSR

Mater · 1 (2), ρ · 2 04 (1 965). This alloy system is between GeTe and

There are 3 mesophase compounds between the two terminal phase compounds of Sh T es, which are Ge2Sb2Te5, GeSb2Te4, and GeSb4Te7, respectively. Matsushita

Yamada et al. Have studied the alloy composition of GeTe-SbJe3 quasi-binary alloy wire, and published it in J. Appl. Phys. 69 (5), p. 2849 (199.1). It has been found in the research that the crystallization time of the amorphous thin film by laser can be less than 100 n s, and the crystallization time of the components toward the Sh T es direction is shorter. When the composition deviates from the quasi-binary alloy wire, the crystallization time increases rapidly. The crystallization temperature also decreases with the increase of S b2 T a, which is within about 2 q 〇. The crystallization process is to form the face-centered cubic (F C c) # structure of the metastable phase first, and then further form the hexagonal crystal structure of the stable phase.

1223808 V. Description of the invention (3)

The company has published a number of U.S. patents on 66813 and 6 systems, such as U.S. Pat. No. 5, 23 3, 5 99 patents proposed in the GeSbTe ternary phase In the figure, GeSb2Te4 and 81) are connected to a certain G point of Ge12Sb39Te49 within the composition range near the G point (7 to 17 atomic percentage (at ·%) Ge, 34 to 44 at ·% Sb, 44 to 54 at ·% Te) has the best recording characteristics (lower jitter value). The U.S. patent

Pat · No · 5, 278, 0 1 1 elaborates that in the composition range near the GeTe-Sb2Te3 and GeTe-Bi2Te3 quasi-binary alloy wires, the partial T e is replaced by S e. The purpose is to improve the recording sensitivity while , And can maintain fast crystallization speed. U.S. Pat. No. 5, 294, 523 proposed to add in the phase diagram Ge: 10 ~ 35 at ·%, Sb:-10 at ·%, Te ·· 4 5 ~ 65 at ·% B and C (between 5-40 at ·%) to increase the number of rewrites.

Gonzalez-Hernandez et al. Discovered in 1992 that there is still a single-phase composition-G e4 S b T e5 near the GeTe-Sb2Te3 pseudo-binary alloy wire, published in

Appl · Phys · Co_ · 11 (4), ρ · 5 57 (1 992) and Solid State Comm · 95 (9), ρ · 5 9 3 (1 9 9 5) ° Ge4SbTe ^ i ^ t The dazzling points all maintain the face-centered cubic structure, and will not further form a hexagonal crystal structure. Ph. 1 ips's J. Η Coomb s and others also support this statement, but their composition is Ge ^ SbgTe52, which is slightly different from Ge4SbTes (published in J. Appl. Lett. 78 (8), ρ 4918 In 1 995). At present, rewritable optical information recording media, especially rewritable optical discs (CD-RW), mostly adopt a recording layer composed of Ag-In-Te-Sb, which is a material currently used for phase change layers. However, the crystallization temperature is relatively south, so the shai phase change recording layer changes from an amorphous structure to a crystalline structure.

0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 7 V. Description of the invention (4) The action of the time relative to the car traffic wiping Crystal structure. [Inventive Content] There is a layer of information recording media in this information. In other words, the optical information recording crystal structure of the present invention wipes the record of the sales record and erases the phase change of the recording medium selected from the following Ga. , Sn, Pb Mb, Ta, Μη When f is wiped with a laser beam, it takes a long time to transform the amorphous structure of the phase change layer into a junction. The purpose of this is to provide a When the rewritable optics wipes the rewritable type 2 with a phase change medium with a lower crystallization temperature and a pulsed laser, it converts the amorphous structure of the phase change layer to The available time is shorter, thus increasing the rate of wiping. An object is to provide an optical information recording method at a crystallization temperature below 610, and its phase change layer still has good overwriting characteristics during the re-wipe process. OBJECT ' The present invention provides a rewritable optical information recording layer, which is composed of a ternary Ge-Sb-M material, in which the group 1, 0, 1 ^,? Formed by the M element? , 81, 111, Si, Ag, An, Ti, Zr, Cr, Ni, Hf, V, W, Mo and Ce e Phase change layer material manufacturing method The phase change layer of the present invention is a Ge-Sb material, In addition, a small amount of μ group elements is added to form a ternary Ge-Sb-M material, and a small amount of M group elements can effectively reduce the crystallization temperature to provide a faster crystallization rate. However, at the same time, the phase change layer with a faster crystallization rate also needs to have sufficient conditions for rapid cooling to enable the stable amorphous structure to be converted into a crystalline structure, which is 0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 8 1223808 V. Description of the invention (5) To achieve the above purpose of the invention, the phase change layer of the rewritable optical information recording medium of the present invention has a Ge element range X = 5 to 25 atomic percent (at ·%), Sb element range y = 70-90 atomic percent (at ·%), and a small amount of group M element z = 2 ~ 2 5 atomic percent (at ·%) 'x + y + z = 100 The temperature at which the phase change layer is transformed from an amorphous structure to a crystalline structure is from 140 to 150. (:, Its crystallization temperature is lower than the currently used phase change layer Ag-In-Te-Sb: (the temperature at which it changes from an amorphous structure to a crystalline structure is 160 ~ 170t), which can reduce the phase change layer from The time for the amorphous state to change to the crystalline state, thereby increasing its crystallization speed, so as to achieve a faster wiping speed when wiping data with a laser, and stable phase transition characteristics. In other words, it has a good overwrite Characteristics. The composition range of the preferred phase change layer of the present invention is χ = 5 to 25 atomic percent (at ·%), y = 80 to 90 atomic percent (at%), and ζ = 2 to 25 atomic percent. (At · 〇 / 〇), γ 丄 "丄 ν = 1 η Λ The phase change optical recording medium of the present invention The phase change optical recording medium of the present invention includes: (a)-substrate; (b)-lower dielectric layer On the substrate, (c) a phase change layer on the lower dielectric layer (d)-an upper dielectric layer on the phase change ^ (e)-a reflective layer on the upper dielectric layer ^ (f ) A protective layer is on the reflective layer I. 'The deposition method of the above steps is RF magnetic control depositing method' (phase) (c)

$ 9Page Description of the invention of Youbian. The t-layer is Na, the percentage r + 〇 /, the mat percentage (at ·%), v = 7Λy + 2 (= η) ′ ζ = 2 ~ 25 atomic percent. ~ 90 atoms B, 0: 100, where M is selected from the group consisting of the following elements (at./〇'X +, In, Ga, Sn: (ad Hf, V, Nb, Ta, Mn, W, MM! C, ", Tl, and u) ^ ^ ^ is formed by the polycarbonate carbonate tree S, (b) the dielectric layer under e is composed of nitride, and (b) the dielectric layer above 'Shangmi: and ί formed. Among them, the nitride system is nitridation; it is a di-complex, or Heguang's oxide system is oxidized stone Xilu' or Λ. (E) The sum of μ © 在 丄 3 码Zinc, or the above ru, "positive π is difficult to achieve: cn., W, and Ta. The protective layer of ⑴ is a high-knife special material. [Poor application method] Ming_ 夂; Let Ershishu and other purposes and characteristics , And advantages can be explained in more detail under the sundial-the preferred embodiment 'i with the attached chart, in detail: this embodiment uses the RF magnetron sputtering method to deposit the lower dielectric layer 3 on the surface, the lower dielectric layer It is formed by, for example, silicon nitride, aluminum nitride, oxidized stone, and anti-plate systems: tritium, manganese tritide, zincated zinc, or a combination of the above. ^ ^ The thickness of the jade layer is 6. ~ 10.nm. 'Its intermediary is made of Ge-Sb materials with different compositions prepared by radio frequency magnetron A1, AU, Ding t from the following metals or their alloys: 0745-9807TWF (Nl); 212-2; WAYNE .ptd Page 10 1223808 V. Description of the invention (7) G e-S b-S η phase change layer 4 with different composition is deposited on the base ore method, and the thickness of the phase change layer is 10 ~ 20 nm The upper dielectric layer 5 is deposited by RF magnetron sputtering: the upper dielectric layer 5 is made of, for example, nitride nitride, aluminum nitride, silicon oxide, oxide boat, rhenium, manganese sulfide, zinc selenide, or the above The combination is formed on the phase change layer 4 with a thickness of 20 to 60 nm. The reflective layer 6 is deposited by RF magnetron sputtering, which is formed by biting its alloy with butyl metal: A1, Ag, Au, Ti, (: 1 ", from 0, from and 1 ^, on the upper dielectric layer 5, the thickness of the reflective layer is 90 ~ 150 nm. A protective layer 7 is coated on the reflective layer 6 by spin coating, The protective layer is made of molecular material, which completes the production of phase-change optical recording media. A sample analysis method in this example is as follows: using inductive coupling Plasma spectrometer (ICP-AES) or energy dispersive spectrometer (EI) χ) for quantitative component analysis of the sample; differential scanning scanning calorimeter (DSC) to measure the crystallization temperature of the amorphous film; The static tester was used to measure the difference between the crystalline and amorphous reflectance and the two-phase transition time; the charge-coupled element CCD was used to record the image of the recording point to observe the recording process; the dynamic tester (DDU- 1 0 0 0) to measure the overwrite characteristics. In this embodiment, the phase change layer composition is analyzed by an inductively coupled plasma spectrometer (ICP-AES) or an energy dispersive spectrometer (EDX), and the phase change layer of each composition is analyzed by a differential scanning calorimeter (DSC). The crystallization temperature Tc of the thin film is shown in Table 1. by

0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 11 1223808

1223808 V. Description of the invention (9) 90 is; in which X = 5 to 25 atomic percent (at%)) Original: + percentage (in.%), Z = 2 1 atomic percentage (at.% Group.z = 100, where M is selected from the following elements

τ%. V, N, P, Bl, In, Ga, WSl, AgU Light wind: 1 VII, Nl, Ηί, V, Nb, Ta In, w, ⑹ heart, rotate the recording medium at a -line speed, And by maintaining the laser energy medium i level, the laser beam is continuously irradiated to the optical information to record the old junction; the temperature is below 160 ° c, the old recording point is used to wipe this, and d; The laser energy is adjusted at the -wiping level and -recording 2 幵 4 by 1 item: (channel timing) (3T ~ 11T) in the optical, ': 2y into 5 already recorded points to record the digital in the optical recording medium m, where the digital signal is the EFM signal of the disc specification. What is the static tester 4 test crystal plate: the difference in emissivity and measurement of the two-phase conversion time =: pole? ⑺: Wave_9_P2: Wavelength 633nm) n 丄 Write and monitor the recording process, -Semiconductor laser diode (wavelength 6 5 9nm) writes a single pulse under a single pulse M7π test strip (Slngle-pulse m〇de), write & record points, and operate another semiconductor laser diode to use niD in + cw mode (cw mode) to monitor and record the spear, that is ^ use " Laser power (nw) and laser pulse (:: 2 The material undergoes a phase change *, which in turn produces optical properties: = a and the difference in reflectivity between amorphous and amorphous, and measured using a static tester = signal ' Crystalline and amorphous f == change time, all files are recorded with charge-coupled elements

1223808 V. Description of invention (ίο) to observe the recording process. The Ges 92Sb7s 2Snie film in this example was written with laser power and laser pulses (20 ~ 70ns) and laser power mW). Figure 2 shows that Ge5_92Sb78.2Sni ^ has a good crystal and Difference in amorphous reflectance. 2. After the cutting, the Ges 92Sb78 gSn film of this example can be written with laser work and laser pulse (20 ~ 70ns) and recorded with the charge stealing first year (10mW) to observe The results obtained during the recording process were well recorded after the Ge5.92Sb? 8 2Snie film was written in the CCD record. Figure 3 shows that the Ge5 92 Sb? 8 2Snie film in this example is using laser power. And write laser pulse (20ns), and wipe it with laser power, power (10mW) pulse (70ns), and then use laser power (〇65mW) and laser results, in the fourth The figure shows the difference between the good amorphous and crystalline reflectance obtained on the j-doped side of the Ges 92Sb? 8 2Snle film. The "Ge5.92Sb78.2Snie" film of this embodiment can be written before and after "," and "&", and written with a laser and laser pulse (20ns), and wiped with a laser power field and a power (10mW) pulse (70ns). Then, using the laser power (0) and the laser result 'and recording with the charge-coupled element CCD 7) The results obtained during the recording process are shown in Figure 5. Good wiping results can be obtained. ° · 92 78.2Sn! 6 film ^ Find the first picture for 3T ~ 11T (channel timing) for the first time —... Χ (eye pattern); the seventh picture is for 3τ ~ ητ (frequency; ^ eye diagram record after recording) The following eye pattern (eye pattern), its results, and time) Ges "St" 78 2 Snle film of the 1000th time is still recorded at the 1000th time.

Page 14 ... ', Eye shape diagram of J iE 1223808 5. Description of the invention (11) (eyepa 11 er η) shows that the optical information recording medium of the present invention has good overwriting characteristics, that is, it is faster Under the crystallization speed, it has stable phase transition properties. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and retouching without departing from the spirit and scope of the present invention. The scope of protection shall be determined by the scope of the attached patent application.

0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 15 1223808 Brief description of the diagram 1 The diagram shows the phase change of the optical loan 9 park total approval ^ OU π recording medium layer diagram 2 It shows the GewSb ^ Sh film and the schematic diagram of the win layer; (Static Tester) The difference between the crystalline reflectance of the static tester 筮 qm and the skeletal-r ck 〇 / day after the static test; Figure 3 shows the image of a recording point recorded by a CCD after the Ge5 92 Sb78 2 Sn16 film was written; How is the electrical coupling of the π piece after the stomach is inserted? Figure 4 shows the G e5 92 Sb? 8 2 S nle film wipe The difference between the amorphous and crystalline reflectance measured by the Static Tester before and after; Figure 5 shows the G 92 S b? 8 2 S η〗 6 Recording points recorded by the charge stealing device CCD after the film is wiped Video; Figure 6 shows the eye pattern recorded after 3 Τ ~ 11T (channel timing) is overwritten for the first time; Figure 7 shows 3 T ~ 11 T (channel timing) during the overwriting Eye pattern recorded after 1000 times. [Explanation of symbols] 1 ~ optical tributes recording medium, 2 ~ substrate

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Claims (1)

1223808 6. Scope of patent application 1. A rewritable optical information recording medium comprising: a substrate and a phase change layer formed on the substrate, the composition range of the phase change layer is represented by GexSbyMz, where X = 5 ~ 2 5 atomic percent (at ·%), y = 7 0 to 9 0 atomic percent (at ·%), z = 2 to 25 atomic percent (at ·%), X + y + z = 1 0 0, where M It is selected from the group consisting of the following elements: B, 0, N, P, Bi, I η, Ga, Sn, Pb, Si, Ag, Au, Ti, Zr, (: r, Ni, Hf, V, Nb, Ta, Mn, W, Mo, and Ce. 2. The optical information recording medium as described in item l of the patent application scope, wherein the phase change layer composition range of GySbyMz is y = 80 ~ 90 atomic percent · ratio (at ·%) 〇3. The optical information recording medium described in item 1 of the scope of patent application, 'wherein the phase change layer has a thickness ranging from 10 nm to 20 nm. 4. The optical information recording medium described in item 1 of the scope of patent application Wherein the substrate is formed of a polycarbonate resin. 5. The optical information as described in item 1 of the scope of patent application. The information recording medium further includes a dielectric layer between the substrate and the phase change layer, and further includes an upper dielectric layer above the phase change layer. 6. As described in item 5 of the scope of patent application Optical information recording medium, wherein the upper dielectric layer and the lower dielectric layer are made of silicon nitride, aluminum nitride, oxidized silicon, oxidized group, zinc sulfide, manganese sulfide, zinc oxide or a combination thereof 7. The optical information recording medium according to item 5 of the scope of patent application, wherein a reflective layer is further included on the upper dielectric layer. 0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 17 1223808 VI. Patent application scope 8. The optical information recording medium as described in item 7 of the patent application scope, wherein the reflective layer is made of the following metals or Formed by alloy: A 1, Ag, Au, Ti, Cr, Mo? W Ta o 9. The optical information recording medium described in item 7 of the scope of patent application, further comprising a protective layer on the upper reflection layer . 10. The optical information recording medium as described in item 9 of the scope of patent application, the protective layer of which is a molecular material. 11. An optical information recording method, comprising the following steps: providing an optical recording medium having a substrate and a phase change layer; wherein the composition range of the phase change layer is represented by GexSbyMz, where X = 5 to 25 atomic percent ( at ·%), y = 7 0 ~ 9 0 atomic percentage (at ·%), z = 2 ~ 25 atomic percentage (at ·%), X + y + z = 1 0 0, where M is selected from the following Groups of elements: B, 0, N, P, Bi, I η, Ga, Sn, Pb, Si, Ag, Au, Ti, Zr, Cr, Ni, Hf, V, Nb, Ta, Mn, W Moi〇Ce; 0745-9807TWF (Nl); 212-2; WA YNE.ptd Page 18 1223808 VI. Patent Application Method, where the thickness of the phase change layer is in the range of 1 4. As in Patent Application Method 1, the substrate is composed of a substrate Polycarbonate 1 5. As claimed in the scope of the first method of patent application, wherein the substrate and the phase change and above the phase change layer further include 1 6. As claimed in the scope of the first patent application method, wherein the upper dielectric layer, and The combination of aluminum, silicon oxide, oxide button, and sulfur. 1 7. As in the first method of the patent application, wherein the upper dielectric layer is 18; as in the first method, the reflective layer is composed of the following Ag, Au, Ti, Cr, Mo 5 W 1 9. If the first method of the scope of patent application is applied, it further includes 20 on the reflective layer. If the first method of the scope of patent application is applied, the protective layer is a polymer with a size of 1 nm to 20 nm. Formed by the optical information recording urethane ester described in item 1. The optical information recording layer described in item 1 further includes a dielectric layer, and a dielectric layer. The optical information recording method described in item 5 The lower dielectric layer is composed of silicon nitride, zinc nitride, sulfide, zinc oxide, or the optical information recording method described in item 5 above, and further includes a reflective layer. Optical information recording side described in item 7 Formed by metal or its alloy: A1, a 〇 The optical information recording side described in item 7 includes a protective layer. Optical information recording material as described in item 9. _ 0745-9807TWF (Nl); 212-2; WAYNE.ptd Page 19