JPS60177446A - Optical disk recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical disk recording medium which permits easy recording, reproducing, erasing and rerecording of information and has high phase stability of a recording state by forming an alloy layer consisting of In and Sb or In and Sb and a specific metal within a specific compsn. range. CONSTITUTION:The alloy film expressed by the formula (X is 55wt%<=X<=80 wt%, Y is 0wt%<=Y<=20wt%, M is >=1 kinds selected from Au, Ag, Cu, Pd, Pt, Al, Si, Ge, Ga, Sn, Te, Se and Bi) is deposited by evaporation on a substrate 2 consisting of polymethyl methacrylate, etc. by irradiating an electron beam from, for example, an electron beam generating source 6 on an alloy material 4 contained in a crucible 5. A protecting film consisting of fluoride such as MgF2, AlF3 or the like or oxide such as TeO3, TiO2 or the like is then provided on an alloy layer. The suitable selection of the compsn. between 120-160 deg.C phase transition temp. of the alloy layer is thus made possible. The recording medium which requires less writing energy and permits stable repeated erasing and writing in the recording phase is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel single-write/playback optical disc recording medium that is writable.

<Prior Art> The original disk originally had an uneven pit array 'ft-recording layer formed on a substrate according to information, and information was reproduced by optically picking up the bit array. but,
A recording method that utilizes the phase transition of solids was developed,
In addition to simply reproducing information, a laser beam is used to both write and reproduce information, making it possible to record 1 bit into approximately 2μ square, which is more than an order of magnitude higher than current high-density magnetic disks. It has become possible to achieve higher recording densities. In addition, unlike magnetic disks, information can be stored in a completely non-contact manner,
Since playback and high-speed random access are possible, there is no risk of deteriorating the recording surface of the disc. In addition, it can be easily constructed to protect the recording surface from dust and dust.
It has the advantage of being able to perform VC without being affected by scratches, etc.

Conventionally, Te or Te'OX (however,
o<x<2) is known. For these recording media, the temperature of the area irradiated with the laser beam rises above the melting point for a short period of time! (When irradiated with +, the part irradiated with light can be recorded as an amorphous state, and if the part irradiated with laser is irradiated for a long time to a temperature slightly higher than the crystallization temperature, it can return to the crystalline state and erase the υ record. However, since the crystallization temperature of Te1j is between 10°C and 60°C, the amorphous state is not stable, and there are problems with the storage stability of recorded T's.On the other hand, Te0X (0<x<2゜)
In order to stabilize the amorphous phase, impurities such as Sn and Ge were added, the crystallization temperature was controlled, and p was stabilized by increasing the activation energy. However, T
eO)c has the disadvantage that it is difficult to control the oxygen concentration, and that the reproducibility of production is poor because different types of elements are added at different times. Furthermore, these materials have a high vapor pressure in their molten state, and when used as recording media for optical discs, the materials scatter every time they are written, reproduced, or rewritten, which is disadvantageous in terms of repeated use.

In view of the above-mentioned circumstances regarding conventional original disk recording media, the present inventor has repeatedly researched optical disk recording media and found that (Engine n1-X5bX)□-YMY system alloy (where MY is Au, Ag, Cu , Pd.

At least one selected from the group consisting of Pt, At, Si, Ge, Ga, Sn, Te, Se and Bi. ) is 106℃ from molten state≠→→same<-,,,-° to room temperature
When rapidly cooled at a cooling rate of /see or higher, a pseudostable phase (hereinafter referred to as
It is called "π phase". ), but when slowly cooling, InS
When it transitions to a mixed phase of b and sb (equilibrium phase) and is in the π phase, I learned that not only is the reflectance 10 to 20% higher than in the mixed phase, but the π phase itself is highly stable. Ta. Furthermore, D"1-zsbx)□YMY alloys in the π phase can be transformed into a mixed phase by heating to the phase transition temperature (100-odd degrees C0) V, erasing the information that has been stored, and improving the They discovered that it is easy to install (replace shoes), and were able to complete the present invention.

<Purpose of the Invention> That is, the present invention provides a source that allows information to be easily recorded, reproduced, and erased at once, has a highly compatible recorded state, and can be repeatedly recorded, reproduced, and erased. The purpose is to provide disc recording media.

<Structure of the Invention> The optical disk recording medium of the present invention for achieving the above object is characterized in that the recording layer has an alloy film having a composition represented by the general formula %. However, X, Y in the above general formula
are 55% by weight ≦X〈80% by weight, 0% by weight≦Y≦20% by weight, and M is Au, Ag, Cu, Pd, Pt,
At.

Represents at least one persimmon selected from St, Ge, Ga1Sn, Te, Se and Bi.

Further, the recording layer has an alloy film having a composition represented by the general formula %, and furthermore, T e 02, V203, v3o6, T i
02, S i 02 or MgFz, Ce
At least one selected from fluorides such as F3 and AtFs is laminated as a protective film. However, X and Y in the general formula are respectively 55 weight ratio ≤
, Al.

Represents at least one of Si, Ge1Ga, Sn, Te, Se, and Bi.

The above general formula (Inx-XsbX)x-yMy alloy is
When the amount of sb added is less than that of 55 coulometric candy, a particularly mixed phase in the range B shown in Figure 1 is formed, and the π phase (composition in the range A shown in Figure 1) is not formed. , if it exceeds 80% by weight, it will become a single phase C of sb and no mixed phase will be formed at all, so information using the phase transition between π phase and mixed a
Recording, playback, and rewriting will no longer be possible.

("1-Xl-X5bX) In the 1-Y alloy, when the addition amount Y of MY exceeds 20 times, the alloy no longer forms a π phase, and as in the above case, information due to phase transition Writing, reproduction, and replacement are no longer possible.Furthermore, as shown in Figure 2, the relationship between the additive metal M composition and the phase transition temperature is as follows for Te, Se, and Bi: curves a and b.
These metals can be varied in various combinations within the range (2) between Au, Ag.

In the case of Cu, Pd and pt, it can be changed within the range ■ between curves e and f, and in the case of Az, st, Qe, Ga and Sn, it can be changed within the range B between curves &lc and d. I can do it. Furthermore, among the metals of each group exhibiting phase transition temperatures in the ranges ■, B, and ■, by changing the combination ft of metals that fall into the heterogeneous range,
An alloy having a transition humidity within a suitable range can be obtained within the range of 160°C.

In the above-mentioned optical optical recording medium, when writing information 'f', the recording layer is irradiated with a high-power laser beam to melt it and then stored at room temperature (ζ If allowed to cool naturally, at a cooling rate of 106 °C/sec or more).゛When rapidly cooled, it transitions to the π phase, and information can be written into it.If the π phase medium is irradiated with a small laser beam of 7 watts, it undergoes a phase transition to a mixed phase, and the information can be erased. can be rewritten.

<Example> Hereinafter, typical embodiments of the present invention will be described.

Example 1 ■Preparation of an optical disk recording medium A mixture of In and SB at a ratio of 30% by weight and 70% by weight, respectively, was placed in a quartz glass and heated and melted at 645°C in a high-frequency heating furnace. Afterwards, the mixture was allowed to cool naturally in the furnace to obtain Ino, 3Sbo, and 7 materials.

Next, as shown in FIG.
0 crn polymethyl acrylate (hereinafter referred to as rPMMA)
It's called J. ) is held by a supporter 3, and the In obtained in the above process is placed in a bell jar 1. ,3Sbo,
7. A zirconia crucible containing material 4 is placed 5, an electron beam generation source 6ft is disposed, and the inside of the jiber jar 1 is evacuated to IX10'~IXIF5Torr by an exhaust device 7, ~, a child beam generation source I n O in crucible 5 from 6,
3S b o, Xl Electron beam t M M=
J L, In, , Sbo, 7'(c') was evaporated to deposit an InD, 3Sbo, 7 alloy film on the surface of the disc 2. Then, the pressure inside the Peltuya 1 was returned to normal pressure, and the disc 2 was allowed to release naturally. It got cold.

The film thickness of the InSb alloy film on the obtained PMMA disk 2 (hereinafter referred to as "Sample N [LIJ") was measured.
．． 7 It was determined that it was 250A.

■ Performance of optical disk recording medium Sample N [Ll obtained by the above process ■ n0,8
The performance was measured with the Sb6.7 alloy film facing upward using the 1-input/regeneration device shown in FIG.

In the writing/reproducing device shown in FIG. 4, the writing side includes an information input source 10, a writing control device 11, a GaAs
It consists of a semiconductor laser 12, a condensing lens 13, and a mirror 14, and the optical output of the GaAs half-quartet laser was 8 mW when writing onto the sample.

On the reproduction side, a GaAs semiconductor laser 15 and a condensing lens 16
, beam, ++7' liter 17, tracking mirror 1
8, a photodetector 19, a playback output control device 20, and a television monitor 21, which record written using the optical output of the GaAs semiconductor (F laser 12) and convert the optical output from the GaAs semiconductor laser to 0. .8 mW VC, the carrier wave-to-noise ratio (hereinafter referred to as the rC7N ratio) of the reproduced signal No. 48 obtained by the photodetector 19 was examined through the regenerator 20, and it was found to be 55%1. After the above C/N ratio measurement was completed, a GaAs semiconductor laser beam with an output of 4 mW was passed over the information omitted surface of sample Na 1, and the convolution information could be erased.

Example 2 In as an evaporation source. .
A sample was obtained in which an In0.45Sb0.55 alloy film having a thickness of 50 mm was formed. Regarding this sample N[L2, the C/N ratio was measured according to the same method as in Example 1, and the value was 55%. Furthermore, the information written in this sample qNα2 could be erased by scanning the sample surface with a 5 mW GaAs' semiconductor laser.

Example 3 As the evaporation source, ("0.45SbO, 55)0
．． 9AuO, 1, (''''0.3SbO, 7) 0.9
AuO,1,”0.2SbO,8)0.8AuO,2,
(InO,45SbO,55)0.9AuO,1' (
InO,3SbO,7)0.8Ag0.2'("0.2
8b0.8) 0.8AgO,2, (InO,45SbO
,55)0.8CuO,2,(InO,3SbO,7)
0.8AgO,2, (InO,2SbO,8)0.8A
g0.2, (Eng.110.45SbO,55)0.8Pd
O,2, (InO,3SbO,7)0.8PdO,2'
(”o, zSbo, 8) o, aPdo, z −(In0
．． 4sSbO, 5s) 0.9PtO, 1% (InO, 3
SbO, 7) 0.9PtO, 1, (InO, 2SbO,
8) 0.9PtO, 1, (InO, 45SbO, 55)
0.9AtO,11 (In., 3Sbg, 7). ,
9AtO,1,"0.2SbO,8)0.9AtO,1
' ``0.45SbO, 55) 0.9SiO, 1% (''
0.38bO, +7-)0.9SiO,1' ”0.2
SbO,8)0.9SiO,1-”0.45SbO,5
5) 0.9"0.1' (InO, 3Sb0.7) 0.
9G80.1%(”0.2SbO,8)0.9GeO,
1, (technO,45SbO,55)0.9GaO,1,
(InO,3SbO,7)0.9GaO,1,”0.2
SbO,8)0.9GaO,1,(In0.45"bo
, 55) 0.9SnO, 1'"0.3SbO, 7) 0
．． 9"no, 1' (Engineering nO, 2SbO, 8) 0.9Sn
O,1'(InO,45SbO,55)0.9"'0
．． 1-(InO,3Sb0.7)0.9”eO,1, (
InO,2SbO,8)0.9TeO,1,”0.45
SbO,55)0.9BiO,1, (In0.3Sb0
．． 7) 0.9B'0.1, CI n o , 251) o
, s) o 1g B 1 o , 1'l'' was used, but the same alloy film deposition method and C/N ratio measurement method as in Example 1 were used. When the DC/N ratio was measured, the results showed that The value was 55%.

Example 4 A protective film was formed on the alloy film of each sample using the same equipment and method as in Fig. 3, except that MgFz was used as material 4 of the vapor deposition source for each sample fabricated in Example 1.2.3. MgF, vapor deposited film at 1.000X to 2,000X
When the C/N ratio was measured using the apparatus shown in FIG. 4, the laser output was 10 to 13 mW, 5 to 8 mW during erasing, and 1 to 1.0 mW during recording and reproduction.
It was found that 5 mW was required.

It was also found that the C/N ratio was 55%, which is the same as the one without the coating.

Furthermore, although the protective film in this example uses MgFg, other fluorides such as CeF3, AtFa, or T
eO2, V2O3, VsOs, Ti0z, Sfo
2 and other oxide films as a protective film #! , similar results were obtained when the formula was

In the above example, (In□-
XSbx)□□I We have explained how to deposit the MY alloy vapor deposition film by vacuum evaporation method, but not by vacuum evaporation method. It may be formed by the ivy method. In addition, although the substrate used was shown to be made of PMMA,
Materials such as acrylic, glass, and At may be used. However, when using highly thermally conductive materials such as glass and At, a thermal insulation layer (i7500A~0
．． It is better to form it to a thickness of about 2 mm.

<Effects of the Invention> As is clear from the above explanation, the yC disk recording medium according to the present invention has a phase transition temperature of 10'C to 60°C, which is higher than that of conventional optical disk recording media such as (1) Knee-Knee Tes Te0X. Because of the low temperature, omitted information will be erased even if the temperature changes while the optical disc is in use or the ambient temperature rises while the optical disc is not in use.However, in the optical disc recording medium of the present invention,
For example, a phase transition of the π phase and the amount of admixture only occurs at temperatures between C and 160°C. Therefore, the stability of written information is high. Furthermore, the usage status of ) °C disk recording media V
In addition, the phase transition temperature can be adjusted to 120°C or more by appropriately selecting the material used, the type of material for the body, and the combination ratio.
It can be freely selected between 160°C.

■ It is possible to write information with an optical output of 8 to 13 mW from a GaAs semiconductor laser (other lasers may be used), and the C/'N ratio of the resulting reproduced signal is about 55%, compared to conventional lasers. Although the ClN ratio of the original disc recording medium using Te and TeOz is about 60%, it cannot necessarily be said to be higher, but the stability of the written information is high and it can be reproduced repeatedly.

[Brief explanation of the drawing]

FIG. 1 shows In1-xSb of the optical disk recording medium of the present invention.
Figure 2 is a characteristic diagram showing the relationship between the composition dependence during the formation of the π phase of the X alloy and the phase transition temperature from the π phase to the mixed phase.
)(Sb)0□-yMy alloy, a characteristic diagram showing the relationship between the compositional dependence of π phase formation and the phase transition temperature from π phase to mixed phase, Figure 3 is used for manufacturing the optical disk recording medium of the example. FIG. 4 is a schematic diagram of the vacuum core. FIG. 4 is a schematic diagram of the recording/reproducing device used to measure the performance of the original disk recording medium of the embodiment. In the drawings, 1... Peltzia, 2... PMMA substrate, 4... Evaporation material, 10... Information input source, 12, 15-GaAs semiconductor laser, 17... Beam splitter, 19... Photodetector, 20... Reproduction output control device, 21... Television monitor. Patent applicant Nippon Telegraph and Telephone Public Corporation Patent attorney Shibu Mitsuishi and one other person Figure 1 50 60 70 80 90 sb concentration (wt%) Figure 2 0 10 20 M composition (wt%)

Claims (1)

[Claims] An optical disc recording medium characterized in that the recording layer has an alloy film having a composition represented by the general formula il+ % formula %. However, X in the general formula
SY is 55 weight coefficient≦X≦80 weight%, 0 weight%≦Y≦20 weight%, and M is Au, Ag, Cu, Pd,
Pt, AL. Represents at least one second selected from St, Ge, Ga, Sn, Te, Se and Bi. (2) The recording layer has an alloy film having a composition represented by the general formula % Formula %, and Te0z, V2O3, V3O5, T i Oz on the upper surface of the recording layer
, 5ift or other oxides such as MgF2, CeFa, A
An optical disc recording medium characterized in that at least one type of fluoride such as LFg is laminated as a protective film. However, x and y in the general formula are respectively 55% by weight≦X≦80weightφ, 0% by weight≦Y≦20weight, and M is Au, Ag, Cu, Pd, Pt,
At. St, , Ge, Ga, Sn, Te,
Represents at least one selected from Se and Bi.