JPH02243390A - Optical recording medium - Google Patents

Abstract

PURPOSE:To achieve the stability in an amorphous phase and the shortening of the crystallizing time of said phase and to perform rewriting operation at a high speed by constituting a recording material of the composition corresponding to a mixture of a specific element of the Group IIIb, a IVbVIb type stoichiometric compound and a multielement stoichiometric compound constituted of two or more elements selected from elements of the Group IIIb, IVb, Vb, VIb and containing at least one of Se and Te in said composition. CONSTITUTION:The recording material constituting a recording material layer 3 has the composition corresponding to a mixture of a IIIbVIb type stoichiometric compound consisting of Ga, In and Tl of the Group IIIb and S, Se and Te of the Group VIb and having a chemical formula represented by IIIbIVb and a multielement stoichiometric compound constituted of two or more elements selected from Ga, In and Tl of the Group IIIb, Ge, Sn and Pb of the Group IVb, As, Sb and Bi of the Group Vb and S, Se and Te of the Group VIb. Since the bond of the atoms of the Group IIIb strong in ion bonding force is contained in the recording material, the free energy of the crystal phase thereof is lowered and the free energy difference between the crystal phase and an amorphous phase becomes large and the crystallizing time thereof is shortened.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention irradiates focused light such as a laser beam to change the optical properties of the irradiated area, and uses the optical change to record information.・Related to rewritable optical recording media that can be played back and erased, in particular, information can be rewritten at high speed,
Furthermore, the present invention relates to an improvement in an optical recording medium that can retain recorded information for a long period of time.

[Prior Art] Conventionally, magneto-optical recording media have been used as rewritable optical recording media for recording information using laser light or the like, and some of them have been put into practical use. In this method, recording is performed by reversing the magnetization of the recording material layer using optical energy and a magnetic field, and a reproduced signal is obtained by detecting the difference in the Faraday rotation angle or Kerr rotation angle depending on the magnetization direction. However, since there is no practical method for performing 8-conversion within at least one sector in this method, it has only been applied to a limited number of fields.

On the other hand, another type of rewritable optical recording medium is crystal
So-called phase-change optical recording media that utilize phase change between amorphous states are currently under research. In this method, two light beams are used to rewrite within one sector (i.e.,
In addition, in the case of a recording medium using a recording material with a short crystallization time, it is possible to override with a single light beam. (Simultaneous rewriting) is possible, so it has the advantage of being applicable in various fields.

As recording materials applied to this type of phase-change optical recording medium, Sb2Te3, which is a binary compound, and Ge-8b-Te, which is a ternary composition, have conventionally been used.
No. 225934] have been proposed, and these recording material layers are irradiated with focused light from a semiconductor laser, etc., and after melting, they are rapidly cooled to form an amorphous phase, which usually corresponds to the recording state. On the other hand, erasing is performed by irradiating focused light with a power lower than that during recording, and returning the data to the crystalline phase by keeping it at the crystallization temperature for a certain period of time.

[Problems to be Solved by the Invention] Incidentally, the recording material applied to this phase change type optical recording medium preferably has a short crystallization time from the viewpoint of simplifying the optical system or improving the transfer speed. In addition, from the viewpoint of retaining recorded information over a long period of time, it is preferable that the amorphous phase is highly stable.

However, although the conventional recording material composed of SbTe3 meets the requirements of a short crystallization time, it has the problem that it cannot retain recorded information for a long period of time due to insufficient stability of the amorphous phase. there were.

On the other hand, Ge-8b-Te disclosed in JP-A No. 63-225934 is synthesized by mixing GeTe, which has a high amorphous phase stability but takes a long crystallization time, with the above-mentioned 5b2Tea. This is intended to improve transfer speed and storage stability of recorded information by providing intermediate properties between Sb and Te3, but the crystallization time is longer than that of SbTe3 due to the addition of GeTe, so it is difficult to obtain a sufficient transfer speed. There was a problem that I couldn't get it.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and its object is to improve the stability of the amorphous phase and reduce the crystallization time thereof. An object of the present invention is to provide an optical recording medium that can perform a rewriting operation at high speed and can retain recorded information for a long period of time.

In other words, the invention according to claim 1 provides a recording material layer on a substrate whose optical properties change reversibly by means of light, heat, etc., and uses the optical change to record, reproduce, and erase information. The above-mentioned recording material is a group IIIb element selected from Ga, in, or Tl and a VI group selected from S, Se, or TO.
It is composed of group B elements and its chemical formula is m, Vl.

A stoichiometric compound of type IIIbVIb expressed as
Group IIIb elements of Ga, in, or Tl, and Ge, Sn
, or a multi-stoichiometric compound composed of two or more elements selected from a group IVb element of Pb, a group Vb element of As, Sb, or 3i, and a group VIb element of S, Se, or Te. and containing at least one of Se and Te. On the other hand, the invention according to claim 5 is different from the invention according to claim 1 above. Similarly, an optical recording medium is provided with a recording material layer on a substrate whose optical properties change reversibly by means of light, heat, etc., and uses the optical change to record, reproduce, and erase information. It is assumed that the recording material is composed of an mb group element selected from Ga, ln, or Tl and a VIb group element selected from S, Se, or Te, and has a chemical formula of IIIb2V.
A stoichiometric compound of type IIIb2VIb3 expressed as Ib3, an IIIb group element of Ga, In, or Tl, and Ge.

Sn or Pb group IVb element, and S, Se or T
It is characterized by having a composition corresponding to a mixture with a multidimensional chemical compound consisting of two or more elements selected from group VIb elements of e, and containing at least one of Se or Te. It is something to do.

In addition, the above ■　　, ■6, ■1, and ■ゎ are periodic Shows the family number of the table.

In the invention according to claim 1, III, Vl. Types of stoichiometric compounds include GaS, GaSe, GaTe
, Ink, InSe, InTe, TlS.

TlSe, TlTe, Ga1nS, Ga1nSe
, GaInse 1Ga2SeTe.

Ga3Se2Te1GaTlSe2 and InTlS
e2, etc. On the other hand, the above-mentioned ■ is a multidimensional chemical compound.

A stoichiometric compound composed of two or more elements arbitrarily selected from group elements, group elements, group elements, group VIb elements, and group VIb elements, such as Ge and Sn.

or a stoichiometric compound of type IV, Vl, consisting of a group IV element selected from Pb and a group vIb element selected from S, Se or Te, and whose chemical formula is expressed as IV, Vl; , Ge, 3n, or Pb
Vb group element and VIb selected from S, Se or Te
A stoichiometric compound of type IVbVIb2 consisting of a group element and having the chemical formula IVbVIb2, and Ga
, In, or Tl, and 5
consisting of a VIb group element selected from 1se or Te,
UibVIb whose chemical formula is expressed as I[[, VI,
There are stoichiometric compounds of the type.

Examples of the above-mentioned IV, Vl, and type stoichiometric compounds include Gem, Gene, GeTe, and sns.

5nSe, 5nTe1 PbS, Pb5e, PbTe,
Examples include Ge5nTe and Ge2SeTe.

In addition, as the stoichiometric compound of the IVbVIb2 type, Teha, Ge52, GeSe2.5nS2.5nSe
There are also 5nTe2 and the like.

Furthermore, as the m, vt, type stoichiometric compounds,
Gas, GaSe, and GaTe mentioned above.

InS, InSe, rnTe, TlS, 11S
e.

TlTe, GaIn52, GaInSe2, Ga2■
nSe3, Ga2SeTe1 GaSeTe, GaTlSe2, and InT
lSe2 etc. are Al.

A recording material having a composition corresponding to a mixture of the above-mentioned III, Vl, type stoichiometric compound and a multi-component stoichiometric compound includes an mb-group element of Ga, ln, or Tl, and Ge, Sn. , or Pb(7)■ group element and A
S%sb or 3i of V, a luminescent element, and three or more elements selected from group VIb elements of S, Se or Te, and Se or T
a stoichiometric compound of the type I, Vl, and a stoichiometric compound of the rV, Vl type, ■ a stoichiometric compound of the vbvIb2 type, and
It is arbitrary as long as it corresponds to the composition of a mixture obtained by mixing a multi-component chemical omega-theoretical compound such as a stoichiometric compound of type III, Vl, type, etc. in an arbitrary ratio, for example, Se or T.
Multi-component compositions such as ternary compositions composed of three types of elements including e, quaternary compositions composed of four types of elements including Se or Te, and more than 5-component and hexa-component compositions are available. be.

Specifically, the above-mentioned DI, Vl, type stoichiometric compounds, and Gem, GeSe, GeTe, and SnS.

5nSe, 3nTe1 Pbs, Pb5e, PbTe5
A mixture composed of three or more elements containing Se or Te obtained by mixing IV and VIb type stoichiometric compounds selected from GeSnTe, Ge2SeTe, etc. in any ratio; Ga GeTe, In G, which constitute the compound from these mixtures
eTe 11n3SnTe, InPbTe,
Stoichiometric compounds such as TlGeTe2 and TlGeTe3, as well as GaGeT from the above mixtures.
e, , and coincident compounds such as InGeTe2 (stoichiometric compounds that do not decompose into other substances up to the melting point), as well as
Among the above-mentioned mixtures, there are solid solutions composed of three or more elements including Se or Te, and mixtures in which the above-mentioned stoichiometric compounds, solid solutions, etc. are mixed in arbitrary proportions.

In addition, the above m, vi, type stoichiometric compounds and Ge
S5GeSe 1SnS2.5nSe2 and 5n
A mixture composed of three or more elements containing Se or Te obtained by mixing IVb''b2 type stoichiometric compounds selected from Te etc. in any proportion, and also a mixture of these. A stoichiometric compound such as GaGeSe3, which constitutes a compound from within the body, and a stoichiometric compound such as Se from the above mixture.
Or a solid solution composed of three or more elements including Te,
Also, there are mixtures in which the above-mentioned stoichiometric compounds, solid solutions, etc. are mixed in arbitrary proportions.

Furthermore, the above m, vr, type schemological compounds, and Gas
, Gage, GaTe, Ink, InSe, InTe,
TlS, Tl8e, TlTe, GaIn52, GaI
nSe2, Ga2■n5e3, Ga2SeTe1Ga3
3e or 3 containing Te obtained by mixing III, Vl, type chemical σ-theoretical compounds selected from se2Te1GaTlS02 and ■nTi502 in any proportion
Mixtures composed of more than one element, as well as GaInSe2 and Ga, which constitute compounds from these mixtures.
2■nSe3 and G a 3 S e T e 2
stoichiometric compounds such as, also from the above mixtures,
GaTlSe, jnllse2, and Ga2Se
Matching compounds such as Te, also Se from the above mixture
Or a solid solution composed of three or more elements including Te,
Also, there are mixtures in which the above-mentioned stoichiometric compounds, solid solutions, etc. are mixed in arbitrary proportions.

Further, in the invention according to claim 5, the above IIIb2VI
As b3 type stoichiometric compounds, each IIIb and ■
ゎ is composed of the same element Ga2S3, GaSe 1
GaTeXIn2S3. In Se, In
Te, In2S3. Tl2S03 and Tl
There are 2Te3, 2STe2, etc., where VIb is composed of different elements, and 2STe2, etc., and 2STe2, etc., where VIb is composed of different elements.

A stoichiometric compound composed of two or more elements selected from group elements, group IVb elements, and group Ib elements, such as I [group Ib elements selected from Ga, ln, or Tl]. , S, Se or Te; a IIIb2VIb3 type stoichiometric compound whose chemical formula is expressed as IIIb2VIb3, Ge, S
a group IVb element selected from n, or Pb, and 5Sse
There are stoichiometric compounds of type rV, Vl, whose chemical formula is expressed by TVbVlゎ, and VIbIb group elements selected from 1 or Te.

The above-mentioned IIIb2VIb3 type stoichiometric compounds include the above-mentioned Ga S , Ga Se , Ga2
Te 1 In2S3, In2Se3, In2Te 1
There are TlS 1Tl Se3, In2STe, etc., and IV, Vl type stoichiometric compounds include the above-mentioned Gem5GeSe, GeTe, 5nSSS.
nSe, 5nTeSPbS1PbSe, PbTe, Ge
Examples include 5nTe2 and Ge2SeTe.

As a recording material having a composition corresponding to a mixture of the above IIIb2VIb3 type stoichiometric compound and a multi-component stoichiometric compound, Ga, In, or Tl III
composed of a group b element, Ge, Sn, or Pb (7) group IVb element, and three or more elements selected from group Vl and S, Se, or Te, and Se or T.
containing at least one of e, the composition of which is "b2VIb
Obtained by mixing a stoichiometric compound of type 3 with a stoichiometric compound of type I Vl or a multi-stoichiometric compound of b2 b3 stoichiometric compound of type IVb Vl, in any proportion. Any composition may be used as long as it corresponds to the composition of the mixture, for example, a ternary composition composed of three elements including Se or Te, and a quaternary composition composed of four elements containing 8e or Te. There are multi-component compositions such as , 5-component compositions, 6-component compositions, etc.

Specifically, Ga S SG a 2 S e
s, Ga Te , In S S In S
e3, InTe, TlS, TlS
A mixture composed of three or more elements containing Se or Te obtained by mixing IIIb2VIb3 type stoichiometric compounds selected from e3, 77, In25Te2, etc. in any ratio, Similarly, from among these mixtures, coincident compounds such as In28Te2, similarly, from among the above mixtures, solid solutions composed of three or more elements including Se or Te, and the above-mentioned coincident compounds and solid solutions are optionally selected. There are mixtures etc. that are mixed at a ratio of .

Further, the above IIIb2VIb3 type stoichiometric compound, Gem, Gene, GeTe, SnS, 5nSe.

5nTe, PbS, Pb5e, PbTe, Ge5nTe
, and IV, V selected from Ge2SeTe, etc.
A mixture composed of three or more elements containing Se or Te obtained by mixing type Iゎ stoichiometric compounds in any proportion, and a compound composed of these mixtures. Ga45nTe.

stoichiometric compounds such as S
There are solid solutions composed of three or more types of elements including e or Te, and mixtures in which the above-mentioned schemiochemical compounds, solid solutions, etc. are mixed in arbitrary proportions.

The basic structure of an optical recording medium using such recording materials is as follows:
It consists of a light-transmissive substrate and a recording material layer formed on this surface. It is also possible to provide a protective layer on the recording material layer for the purpose of preventing the recording material layer from deforming after melting and before solidifying, or for the purpose of preventing mechanical damage, oxidation, etc. of the recording material layer. It is.

In addition to glass, resin materials such as acrylic, polycarbonate, and epoxy can be used as the light-transmissive substrate. When a resin material is used as the substrate, in order to prevent thermal damage to the resin material, an inorganic material made of, for example, SiO2, ZRO, ZNS, etc., or a mixture of these, etc. is used between the recording material layer and the substrate. A dielectric layer may also be provided. Note that in an optical recording medium in which recording, reproduction, and erasing are performed by irradiating focused light from the opposite side of the substrate, the substrate may of course be made of a light-opaque material such as aluminum.

In addition, examples of the material constituting the protective layer include materials similar to those constituting the inorganic dielectric layer, as well as resin materials such as ultraviolet curing resin, acrylic, polycarbonate, and epoxy, and glass. can. Further, the above-mentioned protection ff1ll may be composed of a single layer of these materials,
Alternatively, the structure may be formed by laminating a plurality of the above materials. Furthermore, when the portion in contact with the recording material layer is made of a resin material, an inorganic dielectric layer may be interposed between the portions like the substrate.

On the other hand, as a method for forming the recording material layer, a sputtering method, a vacuum evaporation method, etc. can be used. In other words, the above sputtering method uses multiple targets and appropriately adjusts the power applied to each target to synthesize the desired composition and simultaneously deposits this composition on the substrate. It is also possible to carry out sputtering using one alloy target corresponding to the composition. In addition, as multiple targets in simultaneous sputtering, the above-mentioned IIIbVIb type stoichiometric compounds, IV, Vl, type stoichiometric compounds, r
v, vr, type 2 chemical d-logical compounds, and IIIb2
An alloy target composed of a VIb3 type stoichiometric compound or the like, an alloy target arbitrarily blending the above-mentioned group Ⅰ elements, group IVb elements, ① group elements, and group VIb elements, or the above-mentioned I[ Group Ib elements, Group IVb elements, ■
, a group element, and a group VIb element.

In addition, the vacuum evaporation method described above uses multiple evaporation sources,
A co-evaporation method can be used in which a desired composition is obtained by adjusting the respective deposition rates and simultaneously deposited on a substrate.

Incidentally, in the optical recording medium according to this technical means, the amorphous phase of the recording material layer may correspond to the recorded state and the crystal phase thereof may correspond to the erased state, as in the conventional case. The phase may correspond to the erased state and the crystal phase may correspond to the recorded state, and the selection is arbitrary.

[Function] According to the invention according to claim 1, the recording material constituting the recording material layer is I selected from Ga, ln, or Tl.
Group IIb element and VI selected from S, Se or Te
I and VI consist of group b elements and have the chemical formulas m and Vl. stoichiometric compounds of type IIIb emission of Ga, In, or Tl; and Ge, 3n
, or a group IVb element of Pb, and As, Sb, or B1
It has a composition corresponding to a mixture of a Vb group element and a multi-stoichiometric compound consisting of two or more elements selected from S, Se or Te, a group VIb element, and According to the invention according to claim 5, the recording material constituting the recording material layer is composed of a group IIIb element selected from Ga, In, or Tl, and a group VIb element selected from 5SSe or Te, and has the chemical formula: is IIIb2VIb
3, a IIIb2VIb3 type stoichiometric compound represented by
n, also HaP b (D IV group 6 element, and
The crystallization time of the recording material layer is shortened because it has a composition corresponding to a mixture with a multi-stoichiometric compound composed of two or more selected elements of group VIbIb such as S, Se or Te. In addition, it is possible to improve the stability of the amorphous phase in the recording material layer.

Here, the present inventors speculate as follows regarding the reason why the crystallization time of the recording material layer in the inventions according to claims 1 and 15 can be shortened compared to the conventional Qe-sb-Te. ing.

First, the elements constituting the recording material layer in the conventional and these inventions have electronegativities as shown in Table 1.

The electronegativity values shown in this table are Paulina
This is the electronegativity value of Ph1llips (Philips) obtained by adding the shielding effect by valence electrons to the electronegativity value of Pauling (J, C, Ph1lli
ps, Bonds and Bands in Sem
1 conductors ＾ academic pres
s, Nev Work and London, 197
3. ).

When considering the bonding state between atoms from this electronegativity value, it has been clarified that the larger the difference in electronegativity value of each atom, the more the ionic bonding of the bond between atoms tends to increase. There is.

By the way, the above electronegativity value of Ph1llips is a calculated value for a regular tetrahedral structure, but the electron orbits of the atoms constituting the recording material layer are also regular tetrahedral when including non-bonding electron pairs. , it is possible to apply Ph1llips electronegativity values to these atoms.

Therefore, when we look at the bonding state between each atom in conventional Ge-8b-Te using this Phillips electronegativity value, we find that the above Ge value is 1.35 from Table 1.
, Sb value is 1.31, and Te value is 1.41, so the electronegativity difference between Ge-5b is 0.04
．． The electronegativity difference between 5b-Te is 0.16, and G
The electronegativity difference between e-Te is 0.12, and the above Ge
The ionic bonding force in the Ge-8b bond, 5b-Te bond, and Ge-Te bond that constitute -8b-Te is weak.

On the other hand, if, Vl, type schemiochemical compounds constituting a part of the recording material in the inventions according to claims 1 and 5, and "b2VIb3 type schemiochemical compounds, the electronegativity is The value of is above■.

The electronegativity difference between Te (1,47), which is the smallest among the emissive elements, and Ga (1,13), which has the largest electronegativity value among the IIIb emissive elements, is 0.34; The value of negativity is 3 (1,87
), and T with the smallest electronegativity value among the IIIb emission groups mentioned above.
I The electronegativity difference in question (0,94) is 0.93
The electronegativity difference between the IIIb group emission and the VIb group element is as large as 0.34 to 0.93, and the ionic bonding force between the IIIb group atom and the VIb group atom is strong.

From the above, it is thought that the bonding force between group IIIb atoms and group VIb atoms is stronger than the bonding force (mostly covalent bonding force) between the atoms constituting Ge-8b-Te due to the strong ionic bonding force. .

Therefore, a group IIIb element of Ga, in, or Tl and G
e53n, or a group IVb element of Pb, and As.

sb or 3i V, group element, and 51Se or die
Vl, a multi-stoichiometric compound composed of two or more elements selected from one element, and the above ■.

■, when mixed with chemical compounds of the type, and
A group IVb element of Ga, In, or Tl, a group IVb element of Ge, Sn, or Pb, and a VI element of S, Se, or Te.
Multi-chemical M-theoretical compounds composed of two or more elements selected from group b elements and the above IIIb2VIb3 type chemistry! When a chemical compound is mixed, it contains a group IIIb atom-VIb group atom bond with strong bonding force,
-The free energy of the crystalline phase is lower than that of Ge-Te, and the free energy difference between the crystalline phase and the amorphous phase, that is, the transformation energy is large. It is presumed that the crystallization time is shortened compared to 8b-Te.

Incidentally, Sb2Te3 has a short crystallization time even though it does not contain strong ionic bonds. Although this seems to be contrary to the above discussion, it is thought that the reason why the crystallization time of Sb2Te3 is short is not because the transformation energy is large but because the activation energy is small, and it does not contradict the above argument.

On the other hand, in the inventions according to claims 1 and 5, the reason why the stability of the amorphous phase in the recording material layer is higher than that of conventional recording materials Ge-8b-Te and Sb2Te3 is inferred as follows. ing.

First, since Ge-8b-Te has weak ionic bonding properties and strong covalent bonding properties, when the number of elements increases, the amorphous phase tends to become unstable due to the increase in free energy accompanying the generation of strain. The recording material in the invention according to item 5 has strong ionic bonding properties as described above, and since this ionic bond is a bond with weak restrictions on the bonding direction and bonding distance, it is stabilized even in a somewhat distorted structure, and the above-mentioned The stability of its amorphous phase is higher than that of Ge-8b-Te.

Furthermore, since the recording material in these inventions is a multi-component material with three or more elements, the effect of inhibiting atomic movement due to the difference in atomic radius is strong, and the activation energy is greater than that of the above-mentioned Sb Te3, which is a binary material. Also from this point of view, the stability of the amorphous phase in the recording material layer is high.

Further, according to the inventions according to claims 1 and 5, since the recording material contains at least one of Se and Te, it has light absorption for visible and near-infrared light.

No. table [Example J Examples of the present invention will be described in detail below.

O First Example As shown in FIG. 1, the optical recording medium according to this example consists of an acrylic substrate (1) with a thickness of 1.2ag+, and this substrate (
1) An inorganic dielectric layer (2) made of 5tO2 with a thickness of 100 rv formed on it, and a record made of Qa-Ge-Te with a thickness of 100 n- formed on this non-m dielectric layer (2). A material layer (3) and a thickness 1 formed on this recording material layer (3).
00 nl inorganic dielectric layer (4) made of 5i02 and an adhesive layer (5) made of ultraviolet curing resin on this inorganic dielectric layer (4).
A 1.2# thick acrylic protective plate formed through
6) and its main parts are composed of.

Here, the recording material layer (3) in the optical recording medium is:
It is formed by RF magnetron sputtering using two alloy targets of Ga 7 e and GeTe, and has the composition shown in 1 to 3 of Table 2 by appropriately adjusting the RF power input to each alloy target. I got something.

In addition, 4 to 5 in Table 2 are comparative examples, 4 is an optical recording medium with the same structure as the first example using 5b-Te as the recording material, and 5 is an optical recording medium using Qe-3b-Te as the recording material. This is an optical recording medium with the same structure used.

In addition, the above 4 was formed by RF magnetron sputtering using one alloy target of Sb 2 Te 3, and 5 was formed by RF magnetron sputtering using 2 alloy targets of Sb 2 Te 3 and GeTe. There is.

The light absorption in these optical recording media (1 to 5) ranges from visible to near-infrared, and is small (total of 400
It could be used as an optical recording medium in the range of nrg to 8G011+1.

Therefore, Table 2 shows recording and erasing characteristics when a semiconductor laser with a wavelength of 830 rv is used as a light source.

Table 2 The evaluation criteria in Table 2 were as follows.

That is, regarding "crystallization time", cases where crystallization is possible in 100 ns are indicated by ○, and cases where crystallization is not possible are indicated by X.

Regarding "r stability", those with a crystallization temperature of 120°C or lower are marked with an x, and those with a crystallization temperature of 120°C or higher are marked with an ○.

As is clear from Table 2, the crystallization time of the optical recording media (1 to 3) according to the first example is shorter than that of Comparative Example 5, and information can be recorded and erased faster than before. Moreover, compared to Comparative Example 4, the crystallization temperature was higher and the stability of the amorphous phase was also excellent.

In addition, the crystal phase in Ga-Ge-Te in 1 and 3 is a stoichiometric compound that exists stably at room temperature, as expected from the pseudo-binary phase diagram shown in FIG.
It was confirmed that it was a single phase consisting of aGeTe 5Ga2GeTe3, and in particular, GaGeTe2 in 1 was a coincident compound, had a short crystallization time, was stable against multiple rewrites, and had good repeatability.

O Second Embodiment The optical recording medium according to this embodiment has a recording material layer made of Indium.
- Between the optical recording medium and the path according to the first embodiment, except that it is made of Ge-Te.

Note that this recording material represented by In-Ge-Te is 1n
It is formed by sputtering using a single target obtained by mixing Te and GeTe at a ratio of 50:50.60;40 and 67:33.

The recording and erasing characteristics of this optical recording medium are shown in Table 3 below.

O Third Embodiment The optical recording medium according to this embodiment has a recording material layer made of Indium.
- The difference between the optical recording medium and the path according to the first embodiment is that it is made of 3n-Te.

Incidentally, this recording material represented by In-8n-Te is
It is formed by dual simultaneous sputtering using two alloy targets of nTe and 5nTe.

The recording and erasing characteristics of this optical recording medium are shown in Table 3 below.

◎Fourth Example The optical recording medium according to this example has a recording material layer of I
The optical recording medium and the optical recording medium according to the first embodiment are the same except that it is made of n-Pb-Te.

Note that this recording material represented by In-Pb-Te is
It is formed by dual simultaneous sputtering using two alloy targets of nTe and PbTe.

The recording and erasing characteristics of this optical recording medium are shown in Table 3 below.

O Fifth Embodiment The optical recording medium according to this embodiment has a recording material layer of Tl.
- Between the optical recording medium and the path according to the first embodiment, except that it is made of Ge-Te.

Note that this recording material represented by Tl-Ge-Te is Tl-Ge-Te.
It is formed by dual simultaneous sputtering using two alloy targets of Te and GeTe.

The recording and erasing characteristics of this optical recording medium are shown in Table 3 below.

O Sixth Embodiment The optical recording medium according to this embodiment has a recording material layer made of Ga.
- Between the optical recording medium and the path according to the first embodiment, except that it is configured with Tl-8e.

Note that the recording material designated as Ga-71-8e is Te
Se,! :GaSe in the ratios of 40:60.50:50 and 60:40.

The recording and erasing characteristics of this optical recording medium are shown in Table 3 below.

◎Seventh Example The optical recording medium according to this example has a recording material layer made of Indium.
-11-8e is the difference between the optical recording medium and the path according to the first embodiment.

The recording material designated as In-Tl-8e is In-Tl-8e.
It is formed by dual simultaneous sputtering using two alloy targets of Se and TlSe.

The recording and erasing characteristics of this optical recording medium are shown in Table 4 below.

◎Embodiment C The optical recording medium according to this embodiment has a recording material FJ of G
The optical recording medium and the optical recording medium according to the first embodiment are the same except that it is made of a-3e-Te.

Note that this recording material represented by Ga-8e-Te is made of Ga-8e-Te.
It is formed by dual simultaneous sputtering using two alloy targets of Se and GaTe.

The recording and erasing characteristics of this optical recording medium are shown in Table 4 below.

O Ninth Embodiment The optical recording medium according to this embodiment has a recording material layer made of Indium.
- The difference between the optical recording medium and the path according to the first embodiment is that it is made of 8-Te.

Note that this recording material represented by In-8-Te is In
It is formed by dual simultaneous sputtering using two alloy targets: S and In2Te3.

The recording and erasing characteristics of this optical recording medium are shown in Table 4 below.

Embodiment The optical recording medium according to this embodiment has a recording material layer of Ga.
The difference between the optical recording medium and the optical recording medium according to the first embodiment is the same as that of the first embodiment except that it is constructed of -8n-e.

Note that this recording material represented by Ga-5n-Te is Ga-5n-Te.
It is formed by dual simultaneous sputtering using two alloy targets of 2Te3 and 5nTe.

The recording and erasing characteristics of this optical recording medium are shown in Table 4 below.

◎Apprentice - Example The optical recording medium according to this example has a recording material layer of Ga.
- Between the optical recording medium and the path according to the first embodiment, except that it is constructed of Qe-8e.

Incidentally, this recording material designated by Ga-Qe-3e is made of Ga-Qe-3e.
It is formed by dual simultaneous sputtering using two alloy targets of Se and Ge5e2.

The recording and erasing characteristics of this optical recording medium are shown in Table 4 below.

Table 2 As is clear from Tables 3 to 4 above, Second Example ~
Apprentice - The optical recording media (6 to 29) according to Examples are the optical recording media (1 to 3) according to the first example shown in Table 2.
Similarly, the crystallization time was shorter than that of the comparative example (information could be recorded and erased faster than before, and the crystallization humidity was high and the stability of the amorphous phase was also excellent).

In addition, the crystal phase in 6.8 In-Ge-"re, the crystal phase in 9) n-3n-Te, and the crystal phase in 10 1n-Pb-
Crystal phase in Te, 12.14(7) T I -G
Crystal phase in e-Te, 16 crystal phase in Qa-Tl-8e, 19) crystal phase in n-Tl-8e,
Crystal phase in Ga-8e-Te of 22, In-
Crystal phase in 8-Tek- and 28-Ga-3n-
As expected from the pseudo-binary phase diagrams shown in Figures 3 to 11, the crystalline phase in Te is a stoichiometric compound that exists stably at room temperature, namely InGeTe.
, In2GeTe3, In5nTe, [nPb
Te, TlGeTe, Tl2GeTe,
TJGaSe, ,Tl1nSe,Ga,,5eT
It was confirmed that it is a single phase consisting of In25Te 1 and Ga 5nTe7, and in particular, 6 InGe
Te 116 TJGaSe, 19 TllnSe
22 Ga2SeTe and 25 1n 5
Te2 is a matching compound, has a short crystallization time, and
It was stable against multiple rewrites and had good repeatability.

In addition, the crystal phase in Qa-Qe-3e of 29 is a stoichiometric compound shown by GaGeSe3 that is stable at room temperature, has a short crystallization time, and has stable and repeatable characteristics against multiple rewrites. was good.

[Effects of the Invention] As described above, according to the invention according to claim 1, the recording material constituting the recording material layer is Ga or ln.

or a stoichiometric compound of type m, vr, which is composed of a group IIIb element selected from Tl and a group VIb element selected from 51Se or Te, and whose chemical formula is expressed as Ilr, Vl, and Ga, inl, or mb group element of Tl and Ge.

Sn or Pb group IVb element and As, Sb or 3
It has a composition corresponding to a mixture of a group VB element of i and a multi-component stoichiometric compound consisting of two or more elements selected from group VIb elements of S, Se or Te, and According to the invention according to claim 5, the recording material constituting the recording material layer is composed of a IIIb group element selected from Qal 1n or Tl, and a VIb group element selected from 51se or Te, and has the chemical formula: is a stoichiometric b2 b3 compound of type IIIb2VIb3 expressed as ■ ■ and Qa%in, or Ding! m, group element of Ge1Sn1 or Pb, group IVb element, and VI of S, Se or Te
Since it has a composition corresponding to a mixture with a multi-component stoichiometric compound composed of two or more elements selected from Group B elements, the crystallization time of the recording material layer can be shortened, and It is also possible to increase the stability of the amorphous phase in the recording material layer, so it has the effect of allowing high-speed rewriting and the ability to retain recorded information for a long period of time. .

Furthermore, the recording material constituting the recording material layer of the invention according to claims 1 and 5 contains at least one of Se or Te and has light absorption for visible and near-infrared light, so it is widely used. It has the effect that it can be used with semiconductor lasers, etc.

Further, according to the invention according to claim 8, since the crystalline phase of the recording material constitutes a single phase consisting of a chemical compound, the free energy of the crystalline phase is further reduced, and the crystallization time thereof is reduced. It has the effect that it can be further shortened, and also has the effect that the recording characteristics do not change even if it is rewritten many times because the crystal phase does not undergo phase separation.

Furthermore, according to the invention according to claim 9, since the stoichiometric compounds are composed of matching compounds, segregation does not occur during cooling treatment and the properties do not change further even after being rewritten many times. have.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the layer structure of the optical recording medium according to the example, and FIGS. 2 to 11 are pseudo-binary phase diagrams of the recording materials used in the first example to the apprentice example, respectively. It shows. [Description of symbols] (1)...Substrate (2)<4n...Inorganic M electric layer (3)...Recording material layer (5)...Adhesive layer (6)...Protection plate Figure 2 Patent Applicant Fuji Xerox Co., Ltd. Representative Patent Attorney Tomohiro Nakamura (2 others) rnol, C. Fig. bTe mol, 'Mu 971nTe Fig. 4 nTe O mol @L nTe Fig. C eTe 4゜6゜added ITe mol, % Fig. Optical recording medium 15 Fig. aTe mol, ''/s age Funeral diagram Figure 10

Claims (10)

[Claims] (1) In an optical recording medium that has a recording material layer on a substrate whose optical properties change reversibly by means of light, heat, etc., and records, reproduces, and erases information using the optical change. , the recording material is selected from Ga, In, or Tl.
III_b group element and VI_ selected from S, Se or Te
A III_bVI_b type stoichiometric compound consisting of group b elements and whose chemical formula is expressed as III_bVI_b, and Ga, I
n, or III_b group element of Tl, and Ge, Sn, or P
A mixture of a group IV_b element of b and a multi-stoichiometric compound composed of two or more elements selected from a group V_b element of As, Sb, or Bi, and a group VI_b element of S, Se, or Te. 1. An optical recording medium characterized in that it has a composition corresponding to that of a metal and contains at least one of Se and Te. (2) The multi-stoichiometric compound contains a group IV_b element selected from Ge, Sn, or Pb, and S, Se or Te.
It consists of group VI_b elements selected from
The optical recording medium according to claim 1, characterized in that it is a stoichiometric compound of type IV_bVI_b expressed as V_bVI_b. (3) The multi-stoichiometric compound contains a group IV_b element selected from Ge, Sn, or Pb, and S, Se or Te.
It consists of group VI_b elements selected from
The optical recording medium according to claim 1, characterized in that it is a stoichiometric compound of type IV_bVI_b_2 expressed as V_bVI_b_2. (4) The multi-stoichiometric compound contains a group III_b element selected from Ga, In, or Tl, and S, Se or T.
It consists of group VI_b elements selected from e, and its chemical formula is
The optical recording medium according to claim 1, which is a stoichiometric compound of type III_bVI_b expressed as III_bVI_b. (5) Optical recording, which includes a recording material layer on a substrate whose optical properties change reversibly by means of light, heat, etc., and records, reproduces, and erases information by utilizing the optical changes. In the medium, the recording material is selected from Ga, In, or Tl.
II_b group element and VI_ selected from S, Se or Te
It is made up of group b elements and its chemical formula is III_b_2VI_b_3
A stoichiometric compound of III_b_2VI_b_3 type expressed as III_b_2VI_b_3 type, a III_b group element of Ga, In, or Tl, and G
It has a composition corresponding to a mixture of a group IV_b element such as e, Sn, or Pb and a multi-stoichiometric compound consisting of two or more elements selected from group VI_b elements such as S, Se or Te. An optical recording medium comprising: and at least one of Se and Te. (6) The multi-stoichiometric compound contains a group III_b element selected from Ga, In, or Tl, and S, Se or T.
It consists of group VI_b elements selected from e, and its chemical formula is
III_b_2VI_b expressed as III_b_2VI_b_3
The optical recording medium according to claim 5, which is a _3 type stoichiometric compound. (7) The multi-stoichiometric compound contains a group IV_b element selected from Ge, Sn, or Pb, and S, Se or Te.
It consists of group VI_b elements selected from
6. The optical recording medium according to claim 5, which is a stoichiometric compound of type IV_bVI_b expressed as V_bVI_b. (8) The optical recording medium according to any one of claims 1 to 7, wherein the crystalline phase of the recording material constitutes a single phase consisting of a stoichiometric compound. (9) The optical recording medium according to claim 8, wherein the stoichiometric compound is a coincident compound. (10) Claims 1 to 7 characterized in that the recording material constitutes a single phase made of a solid solution.
Optical recording medium described in Section 1.