KR100312210B1 - an optical information recording medium and a preparation thereof - Google Patents

Abstract

The present invention provides an optical information recording medium having excellent weather resistance and good recording erasing characteristics and repeating characteristics, wherein a Ge-containing layer is formed in contact with the information layer (3), and the layers (7, 8) are formed of GeXN and A diffusion barrier layer composed mainly of at least one selected from GeXON. Here, component (X) consists of 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 elements and at least one element selected from C. The information layer 3 is composed of a phase change material mainly containing three elements of Ge, Te, and Sb.

Description

Optical information recording medium and a method for manufacturing the same

The present invention relates to an optical recording information medium capable of recording information at high density and highway using optical means such as laser beam irradiation, and a method of manufacturing the same.

As a medium capable of recording a large amount of information and reproducing and rewriting at high speed, a magneto-optical recording medium and a phase change recording medium are known. These optical recording media utilize the difference in optical characteristics of the recording material generated by locally irradiating laser light. For example, in the magneto-optical recording medium, the difference in the rotation angle of the reflected light polarization plane caused by the difference in magnetization state is used for recording. In addition, in the phase change type recording medium, the amount of reflected light with respect to light of a specific wavelength is used for recording in a state different from a crystalline state and an amorphous state. Since the phase change type recording medium can simultaneously erase and record the recording by modulating the output power of the laser, there is an advantage that the information signal can be rewritten at high speed.

4 and 5 show examples of the conventional layer structure of the optical recording medium. Resin, such as polycarbonate and polymethyl methacrylate (PMMA), glass, etc. are used for the board | substrate 101. FIG. The information layer (recording layer) 103 is made of a material having a state in which the optical characteristics are different and capable of reversibly changing between these states. In the case of the rewritable phase change type optical disk, the information layer 103 is Te-Sb-Ge, Te-Sn-Ge, Te-Sb-Ge-Se, Te-Sn-Ge-Au, Ag-In-Sb- Materials mainly containing Te, In-Sb-Se, In-Te-Se, and the like are used. The reflective layer 105 is generally made of a metal such as Au, Al, Cr, or an alloy of these metals, and is formed for the purpose of heat radiation effect or effective light absorption of the recording film, but is not an essential layer.

The protective layers 102, 104, and 106 are responsible for protecting the information layer, which prevents oxidation, evaporation or deformation of the information layer material. In addition, by adjusting the film thickness, it is possible to adjust the absorptivity of the optical medium, the reflectance difference between the recording portion and the erasing portion, so that the optical characteristics of the medium are also controlled. As the conditions for the material constituting the protective layer, the above object must be satisfied, and the adhesion to the recording material and the substrate must be good, and the protective layer itself must be a film having good weather resistance without cracking. Do. If these protective layers are used in contact with the information layer, they must be materials that do not damage the optical change of the recording material.

Examples of the protective layer include sulfides such as ZnS, oxides such as SiO ₂ , Ta ₂ O ₅ , and Al ₂ O ₃ , nitrides such as Si ₃ N ₄ and AlN, nitrogen oxides such as SiON and AlON, carbides, and fluorides. Dielectrics, or a suitable combination of these has been proposed. Particularly applied material is ZnS-SiO ₂ .

Conventionally, for example, as shown in Fig. 5, the protective layer is made of two layers, and other materials are used for the two protective layers 102 and 106, thereby improving the adhesiveness to the substrate and the repeatable recording characteristic of the information. A suggestion is also made.

Moreover, the technique of obtaining a favorable film quality by making a protective layer into a composite material of another substance is known. For example, Japanese Unexamined Patent Application Publication No. 63-50931 adds at least one of aluminum oxide and silicon oxide to a composite dielectric of aluminum nitride and silicon nitride and limits the refractive index, thereby providing excellent adhesion to the substrate. An example of obtaining a film-like protective layer is disclosed.

Japanese Unexamined Patent Application Publication No. 2-105351 discloses an example in which a protective dielectric is made of a composite dielectric made of silicon nitride and indium nitride to obtain a film having good ductility with good adhesion to a substrate.

In addition, Japanese Patent Laid-Open No. 2-265051 and Japanese Patent Laid-Open No. 2-265052 have a protective film made of Si, N, and non-electrical resistance elements smaller than Si, so that film splitting does not occur easily and the information layer is protected. An example of obtaining this excellent protective layer is disclosed.

In a conventional optical information recording medium, it has recently been found that the rewriting of a recording is repeated a plurality of times, whereby the mutual diffusion of members and the composition of the information layer change over time between the information layer and the protective layer. By this phenomenon, when the signal rewriting is repeated many times, the signal amplitude gradually decreases, and the jitter value of the mark position of the recording mark increases. That is, the error rate of the recording signal becomes high, which causes a problem that the number of repeatable rewrites is limited.

In view of the above conventional problems, an object of the present invention is to provide an optical information recording medium having excellent weather resistance and having good recording erasing characteristics and repeating characteristics and a manufacturing method thereof.

1 is a sectional view showing an example of the layer structure of an optical information recording medium of the present invention;

Fig. 2 is a (GeX) O.N triangular composition diagram showing a preferable composition range of the diffusion barrier layer in the optical information recording medium of the present invention;

3 is a diagram showing an example of a film forming apparatus of an optical information recording medium of the present invention;

4 is a sectional view showing an example of a conventional optical recording medium;

Fig. 5 is a sectional view showing an example of a conventional optical recording medium.

<Description of Symbols for Main Parts of Drawings>

1: substrate,

2: protective layer,

3: information layer,

5: reflective layer,

7, 8: diffusion barrier layer,

9: vacuum container,

10: substrate,

11: substrate driving device,

12: target,

13: cathode,

14 gas supply port,

15: exhaust port.

In order to achieve the above object, the optical information recording medium of the present invention has an information layer whose optical properties are reversibly changed, and a Ge-containing layer whose main component is one selected from GeXN and GeXON, wherein X is a Group 3 element, It is characterized by consisting of at least one element selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 8 elements, Group 11 elements, Group 12 elements and C. This makes it possible to obtain a medium excellent in weatherability and recording repeatability.

The manufacturing method of the optical information recording medium of the present invention includes a step of forming an information layer in which the optical characteristics are reversibly changed, and a step of forming a Ge-containing layer including one selected from GeXN and GeXON as a main component. The Ge-containing layer is produced by reactive sputtering in a mixed gas containing an inert gas and nitrogen, using a target containing at least Ge and X. X is an element as described above. As a result, the optical information recording medium excellent in weatherability and recording repeatability can be efficiently produced.

An example of the layer structure of the optical information recording medium of the present invention is shown in FIG. The optical information recording medium has a protective layer 2, a first diffusion barrier layer (Ge-containing layer) 7, an information layer (recording layer) 3, and a second diffusion barrier layer (Ge-containing layer) on the substrate 1 ( 8) The reflective layer 5 has a structure laminated in this order.

The diffusion barrier layer is preferably formed to contact at least one side of the information layer 3. The diffusion barrier layers 7 and 8 are formed to prevent atomic diffusion between the information layer 3 and the layer adjacent thereto. The diffusion barrier layer is effective for preventing diffusion of these components, particularly when sulfur or sulfide is contained in the protective layer. The position for forming this layer may be either or both of the information layers 3, but in order to more effectively prevent the diffusion of the information layer and the protective layer, as shown in FIG. When formed on one side of the information layer, it is preferable to form it on the side where the load of heat at the information layer interface is large, that is, the side where the temperature rise at the information layer interface at the time of mark formation and erasure is high. This is usually the incident side of the laser beam.

It is also contemplated that the components contained in the diffusion barrier layer diffuse into the information layer after repeated recording of the information. However, if a material which does not interfere with the optical change of the information layer is appropriately selected and used as a constituent material of the diffusion barrier layer, such damage caused by diffusion can be prevented.

In the present embodiment, the diffusion barrier layers 7 and 8 mainly contain GeXN or GeXON. X is at least one element selected from Group 3 elements, Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 8 elements, Group 11 elements, Group 12 elements and C. In addition, X is not particularly limited, but Ti, V, Cr, Mn, Cu, Zn, Zr, Nb, Mo, Pd, Ag, Cd, Hf, Ta, W, Fe, Co, Ni, Y, La, and It is preferably at least one element selected from Au. X is more preferably at least one element selected from Cr, Mo, Mn, Ti, Zr, Nb, Ta, Fe, Co, Ni, Y and La, and in Cr, Mo, Mn, Ni, Co and La It is preferred that it is at least one element selected.

Although the durability of the medium is more clearly confirmed by the addition of X, it is considered that the added X suppresses the penetration of moisture into the diffusion barrier layer. One of the mechanisms that can be considered is that the Ge-N bonds in the GeN or GeON layers are changed to Ge-O or Ge-OH bonds under high temperature and high humidity conditions and are easily corroded. It is said that the phenomenon of oxidation or hydroxide of Ge is suppressed by this. It is also conceivable that the number of bonds of Ge present in the GeN or GeON layer is suppressed by the addition of X, thereby suppressing the formation of Ge-OH bonds. As X, Cr, Mo, Mn, Ti, Zr, Nb, Ta, Fe, Co, Ni, Y, and La (particularly Cr, Mo, Mn, Ni, Co, La) are preferable.

The diffusion barrier layers 7 and 8 are different from nitrogen nitrides such as boron nitride, aluminum nitride, silicon nitride, and the like, which are conventionally proposed in terms of germanium nitride or nitrogen oxide. Nitride, which has been conventionally used, lacks adhesion to a recording film or a substrate due to internal stress, activity, and the like. On the other hand, germanium nitrate or germanium nitrate has good adhesion to an information layer and the like, and also has an effect of suppressing the movement of elements. X is also added to this nitrification germanium oxide.

In addition, this invention is not limited to the said structure. For example, a structure in which all of the protective layer 2 is replaced with a material of the diffusion barrier layer 7 or another material (for example, a semiconductor such as Si, Ge, Cr or the like) is formed between the diffusion barrier layer 8 and the reflective layer 5. , Mo, Nb, or the like, or a dielectric formed from a variety of dielectrics or a suitable combination thereof, or a relatively thick dielectric layer between the diffusion barrier layer 8 and the reflective layer 5, so-called slow cooling ( Applied to various configurations such as a configuration called a configuration, or a configuration without a reflection layer, a configuration in which the reflection layer is two layers, or a formation of a layer made of another material between the substrate 1 and the protective layer 2. It is possible that these differences in configuration do not limit the present invention.

As the board | substrate 1, resin, such as polycarbonate and PMMA, or glass is suitable, Preferably, the guide groove for inducing a laser beam is provided.

The protective layer 2 is formed for the purpose of protecting the information layer, improving adhesion to the substrate, adjusting the optical properties of the medium, and the like. The protective layer 2 includes sulfides such as ZnS, oxides such as SiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ , nitrides such as Ge ₃ N ₄ , Si ₃ N ₄ , AlN, GeON, SiON, and AlON. It is preferable to use a material made of a dielectric such as nitrogen oxide, carbonide, fluoride, or a combination thereof (for example, ZnS-SiO ₂ ).

The reflective layer 5 is preferably formed of a metal such as Au, Al, Cr, Ni, or an alloy of a metal suitably selected from these.

The information layer 3 includes Ge-Sb-Te-based material, Te-Sn-Ge-based material, Te-Sb-Ge-Se-based material, Te-Sn-Ge-Au-based material, and Ag-In-Sb-Te-based material. It is preferable to use various phase change materials such as materials, In-Sb-Se-based materials, and In-Te-Se-based materials, specifically, alloys of these systems. The information layer 3 includes Te, Se, or Sb as a main component. It is preferable to use a phase change material, and more preferably to use a phase change material mainly containing three elements of Ge, Te, and Sb.

It is preferable that the film thickness of the information layer 3 is 5 nm or more and 25 nm or less. This is because when the film thickness is less than 5 nm, the recording material is less likely to form a layer, and when it is thicker than 25 nm, thermal diffusion in the information layer plane becomes large, and adjacent erasure is likely to occur during high density recording.

The information layer 3 may contain sputtering gas components such as Ar and Kr, H, C, H ₂ O, and the like as impurities, but as long as the object of the present invention is achieved, such impurities may be contained. . In addition, in the diffusion barrier layers 7 and 8 and the protective layer 2, sputtering gas components such as Ar and Kr, H, C, H ₂ O and the like may be contained as impurities as in the information layer 3. As long as the objective of this invention is achieved, such an impurity may be contained.

Hereinafter, the diffusion barrier layers 7 and 8 will be described in more detail.

The composition of this layer is preferably represented by (Ge _1-y X _y ) _g O _h N _i . Where g> 0, h≥0, i> 0, and g + h + i = 100. Although y is a value larger than 0 and smaller than 1, Preferably it is a value of 0.5 or less for the reason mentioned later.

The compositional ratio in the diffusion barrier layers 7 and 8 is the compositional point shown in FIG. 2 in the three-way compositional view having (GeX), O, and N as the peak from the viewpoint of reducing excess atoms.

A ((GeX) _90.0 O _0.0 N _10.0 ), B ((GeX) _83.4 O _13.3 N _3.3 ),

C ((Gex) _35.0 O _0.0 N _65.0 ), D ((Gex) _31.1 O _55.1 N _13.8 )

It is preferable to exist in the range enclosed, and the composition point similarly shown in FIG.

E ((GeX) _65.0 O _0.0 N _35.0 ), F ((GeX) _53.9 O _9.20 N _36.9 ),

It is more preferable to exist in the range enclosed by C and D. Here, (GeX) indicates the total amount of Ge and X.

Since the diffusion barrier layer 7 is susceptible to heat load during recording repetition, the composition ratio in this layer is in the range of EFCD (in other words, the stoichiometry near the Ge ₃ N ₄ -GeO ₂ line in the three-way composition). It is preferably in the composition range close to ( On the other hand, the composition ratio of the diffusion barrier layer 8 is preferably one with no excess N or O in consideration of adhesion to the information layer. Therefore, the Ge ₃ N ₄ -GeO ₂ line is more preferably GeX side.

When there is an excessive amount of Ge or X which is not bound to nitrogen or oxygen, such excess Ge or X may diffuse into the information layer and may cause optical change of the information layer. Conversely, if there is an excess of nitrogen or oxygen which is not bound to Ge or X, these surplus atoms are likewise pushed into the information layer, which may cause a disturbance of recording. Therefore, the composition ratio of (GeX) contained in the diffusion barrier layers 7 and 8 is that the content of X is 50 atom% or less (that is, 0 <y≤0.5 in Ge _1-y X _y ) with respect to the total amount of Ge and X. desirable. This is because if the content of X is more than 50 atom%, the substance (X) tends to be pushed into the information layer after repetition of recording, thereby disturbing the optical change of the information layer. For the same reason, the content of X is more preferably 40 atom% or less, particularly 30 atom% or less, based on the content of Ge and X. On the other hand, it is preferable that content of X is 10 atom% or more with respect to the total amount of Ge and X. This is because when the content of X is less than 10 atom%, the effect of adding the substance (X) may not be remarkable.

The film thickness of the diffusion barrier layer is preferably 1 nm or more. This is because when the film thickness is less than 1 nm, the effect as the diffusion barrier layer is reduced. As an upper limit of the film thickness of a diffusion prevention layer, it is the range from which the laser beam intensity which can record or reproduce the said information layer is obtained about the diffusion prevention layer of the incident layer of a laser beam rather than an information layer, for example. The laser light intensity is appropriately set according to the laser power or the material of the information layer to be applied.

When the diffusion barrier layer is formed in contact with both sides of the information layer, it is preferable that the layers on both sides use a diffusion barrier layer of different composition. For example, the layer located on the laser incidence side of the information layer tends to be subjected to heat load during repetitive recording, so that the content of the substance (X) is smaller than that of the layer located on the side opposite to the laser incidence side. . In addition, since the layer formed directly after the formation of the information layer has a lower adhesiveness with the information layer than the layer formed immediately before the formation of the information layer, the content rate of the substance (X) in the diffusion barrier layer formed immediately after the formation of the information layer is reduced. It is preferable to make more than that in the diffusion prevention layer formed into a film just before information layer film-forming. Therefore, the diffusion barrier layer on the incident side of the laser light is (Ge _1-m X _m ) _a O _b N _c (a> 0, b≥0, c> 0, 0 <m <1, preferably 0 <m≤0.5 ) And the diffusion barrier layer on the opposite side with the information layer interposed therebetween (Ge _1-n X _n ) _d O _e N _f (d> 0, e≥0, f> 0, 0 <n <1, Preferably it is m <n when it has a composition represented by 0 <n <0.5. When the diffusion barrier layer is disposed in contact with the substrate, in order to improve the adhesion between the substrate and the diffusion barrier layer, it is preferable to use a material containing nitrogen in the diffusion barrier layer or to increase the oxygen content at the substrate interface of the diffusion barrier layer. desirable.

Next, a manufacturing method of the optical information recording medium will be described. As a method of manufacturing the multilayer film which comprises an optical information recording medium, sputtering method, the vacuum deposition method, and the chemical vapor deposition method (CVD method) are mentioned. Here, an example using the sputtering method will be described. 3 shows a schematic diagram of an example of the film forming apparatus.

A vacuum pump (not shown) is connected to the vacuum container 9 through the exhaust port 15, so that the inside of the vacuum container 9 can be stored at high vacuum. The gas supply port 14 can supply a certain amount of Ar, nitrogen, oxygen, or a mixture of these gases. The board | substrate 10 is attached to the drive apparatus 11 for autorotating this. The sputtering target 12 is connected to the cathode 13, respectively. The shape of the target is, for example, a disk shape having a diameter of about 10 cm and a thickness of about 6 mm. The cathode 13 is connected to a direct current power source or a high frequency power supply via a switch (not shown). The vacuum vessel 9 and the substrate 10 are used as the anode by grounding the vacuum vessel 9.

In the manufacturing process of the optical information recording medium implemented using such an apparatus, the diffusion barrier layer is formed immediately before and / or immediately after the process of forming the information layer.

As for the target at the time of forming the information layer 3, GeTeSb target is mentioned, for example.

When the diffusion barrier layers 7 and 8 are formed, a film of good quality can be obtained by using the reactive sputtering method. As the sputtering target, it is preferable to use an alloy of Ge and X or a mixture of Ge and X. The target may further contain nitrogen. For example, when GeCrN is formed as a diffusion barrier layer, a GeCr target or a target containing N in addition to this can be used. In addition, it is preferable to use a mixed gas of an inert gas and nitrogen (N ₂ ) as the deposition gas (sputter gas). As the film forming gas, a mixed gas of a gas containing nitrogen atoms such as N ₂ O, NO ₂ , NO, N ₂ , and a mixture thereof and an inert gas may be used. When the film is hard or the film stress is large, it is preferable to mix a small amount of oxygen in the film forming gas. This is because good film quality may be obtained. It is preferable that the total pressure of film-forming gas is 1.0 mTorr or more.

In addition, the nitrogen partial pressure is preferably 10% or more of the total pressure of the deposition gas. This is because if the nitrogen partial pressure is too low, it becomes difficult to form a nitride and it becomes difficult to form a nitride of a desired composition. In addition, the upper limit with preferable nitrogen partial pressure is a range from which stable discharge is obtained, for example, about 60%.

Next, a method of reproducing and erasing the recording of the optical information recording medium of the present invention obtained as described above will be described.

For reproducing and erasing a signal, a semiconductor laser light source, an optical head including an objective lens, a driving device for guiding a position to irradiate a laser beam to a predetermined position, and controlling a position in a track direction and a direction perpendicular to the film surface A tracking control device and a focusing control device, a laser drive device for modulating the laser power, and a rotation control device for rotating the medium are used. These devices are basically used by those skilled in the art.

The recording and erasing of the signal are performed by incorporating the laser light into small spots by the optical system and irradiating the laser light to a medium rotating by the rotation control device. Here, the amorphous state generation power level at which a part of the information layer can be reversibly changed to an amorphous state by irradiation of laser light is P ₁ , and the crystal state generation power level is determined to be P ₂ by laser irradiation. By modulating the power of the laser light to be irradiated between P ₁ and P ₂ , a recording mark or an erasing portion is formed, and information recording, erasing, or writing of the upper and lower surfaces is selectively performed. Here, part of the irradiation power of the laser light P ₁ is a so-called multi-pulse forming an example of a pulse. However, you may comprise with the pulse which does not use a multipulse.

On the other hand, the P _1, lower than any one of power levels of P _2, that the optical state of a recording mark by irradiation of the laser beam at a power level without being affected, but also the reproduction of recording marks from the medium by the irradiation The power level at which sufficient reflectance is obtained is referred to as the reproduction power level P ₃ . A signal from a medium obtained by irradiating a laser beam having a power level of P ₃ is read by a detector, and information signals are reproduced.

The conditions are illustrated below. The wavelength of the laser light is 650 nm, the numerical aperture of the objective lens used is 0.60, the signal method is the EFM modulation method, the shortest bit length is 0.41 mu m, and the scanning speed of the laser light in the track direction is 6 m / s. The track pitch uses a substrate in which groove portions (also referred to as grooves) and land portions (between groove portions and groove portions) are alternately formed at intervals of 1.48 mu m, that is, 0.74 mu m. Of course, you may use the board | substrate with which the ratio of the width | variety of a groove part and a land part differs. However, the method of using the optical information recording medium is not limited to the above conditions.

In addition, it is preferable to perform so-called land groove recording for recording, reproducing, and erasing information signals in both the groove portion and the land portion of the guide groove. This is because it leads to a larger capacity of the media. At this time, it is necessary to study the depth and shape of the guide groove, the composition of the reflectance of the medium, and the like so that crosstalk and cross erasure do not occur.

Example 1

In the following examples, weather resistance and repeatability of recording were evaluated by the following points. Evaluation of weather resistance was carried out at 90 ° C. 80% acceleration test for 200 hours, and the presence or absence of peeling was observed with an optical microscope every 100 hours. A peeling was not observed at all after 200 hours, but peeling did not occur after 100 hours, but peeling occurred after 200 hours, and B peeling was observed after 100 hours.

Repeatability of recording is based on the EFM signal method, and records random marks of 3T to 11T length under the condition that the shortest mark length is 0.61µm, and the jitter value between the front end and the rear end of the mark is defined as the window width (T). The dividing value does not exceed 13% between the front end and the rear end after 200,000 repeated recordings.A, after the repeated 100,000 times, it does not exceed 13% between the front end and the rear end. One of the leading edges exceeded 13% and B, and the one of the leading edges and the trailing edges exceeded 13% after 100,000 repeated recordings.

An optical information recording medium having the configuration as shown in Fig. 1 was produced by the sputtering method as described above. Here, as the substrate 1, a disc-shaped polycarbonate resin having a film thickness of 0.6 µm and a diameter of 120 mm was used as the protective layer _{2, in} which 20 mol% of SiO ₂ was mixed with ZnS, and as the information layer 3, Ge-Sb. As the reflective layer 5, an Al alloy was used as the phase change material mainly containing -Te alloy. As the composition of the information layer 3, Ge _22.0 Sb _25.0 Te _53.0 is employed here, but a composition other than this may be used.

Sample (1) where GeN was used for diffusion barrier layer 7 and GeNiN for diffusion barrier layer 8, GeNr for diffusion barrier layer 7 and GeCrN. Sample (3) where GeN and diffusion barrier layer 8 were GeCoN (7), GeN and diffusion barrier layer 7 when GeN and diffusion barrier layer 7 were used. In the case of using GeN and the diffusion barrier 8 as GeMnN, the sample 5 and the diffusion barrier 7 are GeN and the diffusion barrier 8 GeLaN as the sample 6 and the diffusion barrier 7 In the case where GeN, the diffusion barrier layer 8 is made of GeTiN, the sample (7), the diffusion barrier layer 7 is made of GeN, the diffusion barrier layer 8 is made of GeZrN, the sample (8), the diffusion barrier layer 7 is made of GeN, The case where the diffusion barrier layer 8 was made GeNbN was used as the sample 9. For comparison, the case where both of the diffusion barrier layers 7 and 8 were made of GeN was used as a sample (0). When forming GeMN layers (M = Ni, Cr, Co, Mo, Mn, La, Ti, Zr or Nb) and GeN layers, the target material is GeM and Ge, respectively, and the M content in the GeMN layer is Ge content. It was made to be 25 atom% with respect to the total amount of and M content. This ratio was also analyzed by ICP emission spectrometry.

The film thicknesses of the diffusion barrier layers 7 and 8 of the samples (0) to (9) were set to 10 nm and 20 nm, respectively. In addition, the film thickness of the protective layer 2 was 120 nm, the film thickness of the information layer 3 was 20 nm, and the film thickness of the reflective layer 5 was 150 nm in common.

When the protective layer 2 and the information layer 3 are formed, a gas containing 2.5 vol.% Of nitrogen mixed with Ar is supplied at a constant flow rate such that the partial pressures are 1.0 mTorr and 0.5 mTorr, respectively, and DC 1.27 W is supplied to the cathode. / Cm 2 and RF 5.10W / cm 2 were supplied with the power. The mixing of nitrogen gas in the sputter gas is for controlling the mass movement of the medium after repeated recording. The effect of the present invention can be obtained even when nitrogen is not supplied from the sputter gas or when nitrogen is mixed with the sputter gas. When the reflective layer 5 was formed, Ar gas was supplied so as to have a partial pressure of 3.0 mTorr, and a power of DC 4.45 W / cm 2 was applied thereto. As the rare gas in the sputter gas, in addition to Ar, a rare gas capable of sputtering such as Kr may be used.

When the diffusion barrier layers 7 and 8 are formed, the sputter gas is mixed with Ar and nitrogen, the sputter gas pressure is 10 mTorr, and the sputter power density is 6.37 W / cm 2, and the diffusion barrier layer 7 is formed. The partial pressure of nitrogen in the sputtering gas was changed to 40% (nitrogen value of 40 vol.%) And the partial pressure of nitrogen in the sputtering gas when the diffusion barrier layer 8 was formed was changed to 10%, 20%, 30%, and 40%. At this time, the amounts of nitrogen contained in the films of the diffusion barrier layers 7 and 8 were 22 atom%, 37 atom%, 50 atom% and 56 atom%, respectively. In addition, the oxygen content in the film was 4 atom%, 5 atom%, 6 atom%, and 7 atom%, respectively. Oxygen is contained because impurity oxygen present in the chamber is contained in the film. In addition, the ratio of nitrogen and oxygen was analyzed by Retherford backcattering spectroscopy.

Table 1 shows the results of the characteristics evaluation on the produced disc-shaped medium.

Table 1

Nitrogen partial pressure medium number diffusion barrier in film forming gas 10% 20% 30% 40% 7 8 Weather resistance repeat Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample 0 GeN GeN A B A A B A C A sample 1 GeN GeNiN A B A A A A A A Sample 2 GeN GeCrN A B A A A A A A Sample 3 GeN GeCoN A B A A A A B A Sample 4 GeN GeMoN A B A A A A B A Sample 5 GeN GeMnN A B A A A A B A sample 6 GeN GeLaN A B A A A A B A sample 7 GeN GeTiN A B A A A A B A sample 8 GeN GeZrN A B A A A A B A Sample 9 GeN GeNbN A B A A A A B A

Further, the diffusion barrier layer 8 is made of GeN and the diffusion barrier layer 7 is made of GeMN (M is the same as above), and the partial pressure of nitrogen in the sputter gas when forming the diffusion barrier layer 8 is constant at 30%, and the diffusion barrier layer is formed. The media produced under the same conditions as Samples (1) to (9) were respectively sampled (10) to (18) except that the partial pressure of nitrogen in the sputtering gas at the time of forming (7) was changed to 40%, 50%, and 60%. ) As in the above, the case where all the diffusion barrier layers 7 and 8 are made of GeN is referred to as sample (0 '). The results of evaluating these media are shown in Table 2.

Table 2

Nitrogen partial pressure medium number diffusion barrier in film forming gas 40% 50% 60% 7 8 Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample0 'GeN GeN ABAABA Sample 10 GeNiN GeN ABAAAA Sample 11 GeCrN GeN ABAAAA Sample12 GeCoN GeN ABAAAA Sample13 GeMoN GeN ABAAAA Sample14 GeMnN GeN ABAAAA Sample15 GeLaN GeN ABAAAA Sample16 GeTiN GeN ABAAAA Sample GeNNNN18 ABAAAA

As mentioned above, it can be seen from the results of Tables 1 and 2 that the use of GeMN as the diffusion barrier layer improves weatherability without compromising the repeatability of recording compared to the case of using GeN.

Next, the diffusion barrier layers 7 and 8 are made of GeN and GeCrN, respectively, and the ratios of the Ge content of the Cr content and the total content of the Cr content in the GeCrN film are 5%, 10%, 20%, 30%, 40%, Discs changed to 50% and 60% are produced, and these media are made into samples 19, 20, 21, 22, 23, 24, and 25 in order. The layer structure of the disk is the same as that of the sample 2 described above, and the nitrogen partial pressure at the time of forming the diffusion barrier layer 7 is constant at 40%, and the diffusion barrier layer 8 is at 20%, 30%, 40%. Changed. The evaluation results of these disks are shown in Table 3.

Table 3

Nitrogen partial pressure medium number in the film forming gas Cr / (Ge + Cr) 20% 30% 40% Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample 0 0 A A B A C A Sample 19 5 A A B A B A Sample 20 10 A A A A A Sample 21 20 A A A A A A Sample 22 30 A A A A A A Sample 23 40 A A A A A A Sample 24 50 A B A A A A Sample 25 60 A C A B A B

It can be seen from Table 3 that the effect of adding Cr becomes remarkable when the Cr content is 10% or more. However, when the Cr content was 60% or more with respect to Ge, the repeatability of recording decreased slightly. It is considered that this is because Cr is more difficult to bind to nitrogen than Ge, and excess Cr that does not bind to nitrogen is present in the film, and these atoms are pushed into the information layer to deteriorate the recording repeatability. The Cr content in the resin is preferably 50% or less and 40% or less with respect to the total amount of Ge and Cr.

The results of evaluating the disks produced in the same manner as above except for using Mo or Ti instead of Cr are shown in Tables 4 and 5.

Table 4

Nitrogen partial pressure medium number in the film forming gas Cr / (Ge + Mo) 20% 30% 40% Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample 0 0 A A B A C A Sample 26 5 A A B A B A Sample 27 10 A A A A B A Sample 28 20 A A A A B A Sample 29 30 A A A A B A Sample 30 40 A A A A B A Sample 31 50 A A A A B A Sample 32 60 A C A B B B

Table 5

Nitrogen partial pressure medium number Ti / (Ge + Ti) in film forming gas 20% 30% 40% Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample 0 0 A A B A C A Sample 33 5 A A B A B A Sample 34 10 A A A A B A Sample 35 20 A A A A B A Sample 36 30 A A A A B A Sample 37 40 A A A A B A Sample 38 50 A B A B B B Sample 39 60 A C A B B B

Example 2

An optical information recording medium was produced in the same manner as in Example 1 except that the diffusion barrier was changed as follows.

Sample 40, wherein the diffusion barrier layer 7 is made of GeON, diffusion barrier layer 8 is made of GeNiON, and the diffusion barrier layer 7 is made of GeON, and the diffusion barrier layer 8 is made of GeCrON. (42) GeON and diffusion barrier layer 8 are GeCoON samples 42, diffusion barrier layer 7 is GeON and diffusion barrier layer 8 is GeMoON sample 43 and diffusion barrier layer 7 In the case of using GeON and the diffusion barrier layer 8 as GeMnON, the sample 44 and the diffusion barrier layer 7 as GeON and the diffusion barrier layer 8 as GeLaON, the sample 45 and the diffusion barrier layer 7 Sample 46 is used for GeON and diffusion barrier layer 8 is GeTiON, Sample 47 is used for diffusion barrier layer 7 and GeZrON is diffusion barrier layer 7 for GeZON. A case where the diffusion barrier layer 8 was made of GeNbON was used as a sample 48. For comparison, the case where all of the diffusion barrier layers 7 and 8 were made of GeON was used as a sample (0). [0100] Also in this embodiment, the M content contained in the GeMN layer was 25 atom relative to the total content of Ge content and M content. It was made to be%.

In addition, the sputtering gas at the time of forming the diffusion prevention layers 7 and 8 was made into the mixed gas of Ar, nitrogen, and oxygen. The sputter gas pressure was 10 mTorr and the sputter power density was 6.37 W / cm 2 in common. The nitrogen partial pressure in the sputter gas when forming the diffusion barrier layer 7 is constant at 40%, the nitrogen partial pressure is 3%, and the nitrogen partial pressure in the sputter gas when forming the diffusion barrier layer 8 is 10%, 20%, 30. % And 40%, and the oxygen partial pressure was kept constant at 3%. At this time, the amount of nitrogen contained in the film of the diffusion barrier layer 7 was 58 atom%, and the amount of oxygen was 20 atom%. The amount of nitrogen contained in the film of the diffusion barrier layer 8 was 24 atom%, 40 atom%, 51 atom%, 58 atom%, and the oxygen content in the film was 8 atom%, 13 atom%, 17 atom%, and 20 atom%, respectively.

Table 6 shows the results of the characteristic evaluation on the produced disc-shaped medium.

Table 6

Nitrogen partial pressure medium number diffusion barrier in film forming gas 10% 20% 30% 40% 7 8 Weather resistance repeat Weather resistance repeat Weather resistance repeat Weather resistance repeat Sample0 "GeON GeON AABACACASample40 GeON GeNiON AAAAAABASample41 GeON GeCrON AAAAAABASample42 GeON GeCoON AAAAAABASample43 GeON GeMoON AAAAAABASample44 GeON GeMnON AAAAAABASample45 GeON GeLaON AAAAAABASample46 GeON GeAAONAAAAABBAZONAAAABBAZAAAABBASample AAAAABBA

It can be seen from Table 6 that the use of GeMON as the diffusion barrier layer improves weatherability without compromising the repeatability of recording compared to the case of using GeON. However, when the oxygen-containing layer is used as the diffusion barrier layer, the repeatability is improved as compared with the case where the oxygen content is at the impurity level, but the weather resistance is somewhat lowered.

As described above, a layer containing at least one selected from GeXN and GeXON as a main component is disposed in contact with at least one of the information layers, and X is a Group IIIa element, a Group IVa element, a Group Va element, a Group VIa element, and a Group VIa element. By using at least one element selected from the Group VIIIa element, the Group Ib element, the Group IIb element, and C, it is possible to obtain an optical information recording medium having excellent weather resistance and excellent repetitive characteristics of erasing the information signal.

Claims (24)

(Correction) Consists of a phase change material with reversible optical properties, Ge-Sb-Te-based material, Te-Sn-Ge-based material, Te-Sb-Ge-Se-based material, Te-Sn-Ge-Au An information layer made of a material material, an Ag-In-Sb-Te material, an In-Sb-Se material, an In-Te-Se material, or an alloy of these materials; Having a Ge-containing layer in contact with at least one of the information layers, the Ge-containing layer having as its main component any one selected from GeXN and GeXON; X is at least selected from Ti, V, Cr, Mn, Cu, Zn, Zr, Nb, Mo, Pd, Ag, Cd, Hf, Ta, W, Fe, Co, Ni, Y, La, Au and C An optical information recording medium comprising one element. (delete) The optical information recording medium according to claim 1, wherein the Ge-containing layer is in contact with both sides of the information layer. (Correction) The optical information recording medium according to claim 3, wherein the content rate of X in the Ge-containing layer is different on both sides of the information layer. 4. The Ge-containing layer of claim 3, wherein the Ge-containing layer located on the laser incidence side of the information layer is (Ge _1-m X _m ) _a O _b N _c (0 <m <1, a> 0, b≥0, c> 0 and a Ge-containing layer having a composition represented by a + b + c = 100 and located on the side opposite to the laser incident layer is (Ge _1-n X _n ) _d O _e N _f (0 <n <1, d> 0, e≥0 , f> 0, d + e + f = 100), and have an relationship of satisfying m <n. The optical information recording medium according to claim 1, wherein the composition ratio of Ge and X in the Ge-containing layer is represented by Ge _1-k X _k (0 &lt; _k ? 0.5). The composition ratio according to claim 1, wherein the composition ratio of (GeX), O, and N in the Ge-containing layer is in the three-way compositionality of (GeX), O, N. A ((GeX) _90.0 O _0.0 N _10.0 ), B ((GeX) _83.4 O _13.3 N _3.3 ), C ((Gex) _35.0 O _0.0 N _65.0 ), D ((Gex) _31.1 O _55.1 N _13.8 ) Optical information recording medium, characterized in that the range is surrounded by. 8. The optical information recording medium according to claim 7, wherein the composition ratio of Ge and X contained in the Ge-containing layer is represented by Ge _1-p X _p (0 < _p ? 0.5). The optical information recording medium according to claim 1, wherein the thickness of the Ge-containing layer is 1 nm or more. The optical information recording medium according to claim 1, wherein X contains at least one element selected from Cr, Mo, and Mn. An optical information recording medium according to claim 1, wherein X contains at least one element selected from Ti, Zr, Nb and Ta. The optical information recording medium according to claim 1, wherein X contains at least one element selected from Fe, Co, and Ni. The optical information recording medium according to claim 1, wherein X contains at least one element selected from Y and La. The optical information recording medium according to claim 1, wherein the information layer is a phase change material mainly composed of any one element selected from Te, Se, and Sb. The optical information recording medium according to claim 1, wherein the information layer is a phase change material mainly containing three elements of Te, Sb, and Ge. (Correction) Consists of a phase change material with reversible optical properties, Ge-Sb-Te-based material, Te-Sn-Ge-based material, Te-Sb-Ge-Se-based material, Te-Sn-Ge-Au Forming an information layer formed of a material material, an Ag-In-Sb-Te material, an In-Sb-Se material, an In-Te-Se material, or an alloy of these materials; Having a step of forming a Ge-containing layer having as its main component any one selected from GeXN and GeXON in contact with at least one of the electrical information layers, The Ge-containing layer is produced by reactive spattering in a mixed gas containing inert gas and nitrogen, using a target containing at least Ge and X. Wherein X is Ti, V, Cr, Mn, Cu, Zn, Zr, Nb, Mo, Pd, Ag, Cd, Hf, Ta, W, Fe, Co, Ni, Y, La, Au, and C At least one element selected. (Correction) The method of manufacturing an optical information recording medium according to claim 16, wherein the mixed gas further contains nitrogen. (Correction) The method according to claim 16, wherein the first step of forming a first Ge-containing layer is formed, the second step of depositing an information layer on which the optical properties are reversibly changed on the first Ge-containing layer, and A third step of forming a second Ge-containing layer on the information layer is provided in this order, and the content of nitrogen in the mixed gas in the first step is equal to that of nitrogen in the mixed gas in the third step. A method for producing an optical information recording medium, characterized in that it is different from the content rate. 19. The method of manufacturing an optical information recording medium according to claim 18, wherein the content of nitrogen in the mixed gas in the first step is higher than the content of nitrogen in the third step. 17. The method of claim 16, further comprising: a first step of forming a first Ge-containing layer, a second step of depositing an information layer on which the optical properties are reversibly changed on the first Ge-containing layer, Has a third step of forming a second Ge-containing layer in this order, and the composition ratio of Ge and X in the target used in the first step is Ge _1-m X _m (0 <m <1), When the composition ratio of Ge and X in the target used in the third step is represented by Ge _1-n X _n (0 <n <1), the relationship of m <n is satisfied. . The method of manufacturing an optical information recording medium according to claim 16, wherein the target is made of a mixture of Ge and X. 17. The method of claim 16, wherein the target is made of an alloy of Ge and X. The method of manufacturing an optical information recording medium according to claim 16, wherein the total pressure of the mixed gas is 1.0 mTorr or more. 17. The method of manufacturing an optical information recording medium according to claim 16, wherein the nitrogen partial pressure in the mixed gas is 10% or more.