KR20090129758A - Information recording medium and method of manufacturing the same - Google Patents

Abstract

PURPOSE: An information recording medium and a manufacturing method thereof are provided to heat locally an amorphous source material layer, thereby forming a plurality of crystallized ferroelectricity recording areas. CONSTITUTION: An information recording medium(100) comprises a recording layer(30). The recording layer has a plurality of recording areas(30a) which are separated by the inactive area(30b) of the recording layer. The recording area is the crystalline ferroelectricity area. The inactive area is the amorphous ferroelectricity area containing the source material of ferroelectricity. The source material comprises one among PbTiO3, Pb(Zr,Ti)O3, (Pb,La)TiO3, PbZrO3, KNbO3, LiTaO3, LiNbO3, and BiFeO3. The recording area comprises one among PbTiO3, Pb(Zr,Ti)O3, (Pb,La)TiO3, PbZrO3, KNbO3, LiTaO3, LiNbO3, and BiFeO3.

Description

Information recording medium and method of manufacturing the same

The present invention relates to an information recording medium, and more particularly to a ferroelectric information recording medium and a manufacturing method thereof.

A method that can overcome the recording density limit of a recording medium (hereinafter, continuous medium) using a continuous recording layer, wherein the bit area or track area is structurally Patterned recording media (hereinafter referred to as patterned media) that are isolated / separated from each other have been proposed. In the case of the magnetic recording method, the recording density of the patterned medium is known to be about 1 Tbit / in ² or more, which is much higher than that of the continuous medium. In the case of the electrical recording method, a higher recording density can be realized than the magnetic recording method.

However, there is a problem in that the process of manufacturing the patterned medium is complicated and the recording layer is easily damaged or contaminated during the process. More specifically, the recording layer of the patterned medium forms a mask having a nano-pillar array structure on a ferroelectric layer or a magnetic layer, and then uses the mask as an etching barrier to form the ferroelectric layer or The magnetic layer is formed by patterning. Alternatively, after forming a template having a nano-hole array structure on the surface of the substrate or the substrate, the ferroelectric material or the magnetic material is filled in the hole array by vacuum deposition or electroplating. A recording layer of a patterned medium is formed. Such a manufacturing method requires an etching process, a lift-off process, an electroplating process, a washing process and a planarization process (polishing process), and the recording layer is etched or chemically damaged. There is a problem that can be contaminated, the process is complicated and expensive. In addition, in the conventional method described above, it may be difficult to form a recording layer having a uniform physical property and size as a whole.

The present invention provides a ferroelectric information recording medium capable of increasing the recording density and a method of manufacturing the same.

An embodiment of the present invention includes a recording layer having a plurality of recording regions separated from each other by an inactive region, wherein the recording region is a crystalline ferroelectric region, and the inactive region is an amorphous non-containing source material of ferroelectric. An information recording medium is provided which is a ferroelectric field.

The source material may be one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ .

The source material comprises PbO and TiO _2, or PbO, including ZrO, and TiO _2, or include PbO, LaO and TiO _2, or include PbO, and ZrO _2, or including a KO and NbO _2, or LiO and TiO ₂ , LiO and NbO ₂ , or BiO and FeO ₂ .

The recording area may be a crystalline area including one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ .

A conductive layer may be further provided on the inactive region.

A conductive layer may be further provided on the recording layer.

Another embodiment of the present invention comprises the steps of forming an amorphous layer; And changing a plurality of areas spaced apart from each other in the amorphous layer into a crystalline recording area.

The amorphous layer may include a ferroelectric source material, and the recording area may be a ferroelectric area.

The amorphous layer may be formed of one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ .

The amorphous layer may be formed in a multilayer structure, in which case the multilayer structure includes a PbO layer and a TiO ₂ layer, or includes a PbO layer, a ZrO layer and a TiO ₂ layer, or a PbO layer, a LaO layer, and a TiO ₂ layer. A layer, comprising a PbO layer and a ZrO ₂ layer, comprising a KO layer and a NbO ₂ layer, comprising a LiO and TiO ₂ layer, comprising a LiO and NbO ₂ layer, a BiO layer and a FeO ₂ layer It may include.

The changing of the plurality of areas of the amorphous layer into the recording area may include heating the plurality of areas.

The plurality of regions of the amorphous layer may be heated with one of light, E-beam, and resistive probe.

A conductive layer may be formed on the amorphous layer between forming the amorphous layer and changing the plurality of regions of the amorphous layer to the recording region.

When the plurality of areas of the amorphous layer is changed into the recording area, at least a portion of the conductive layer located on each of the plurality of areas may be diffused into the respective plurality of areas corresponding thereto.

After changing the plurality of areas of the amorphous layer to the recording area, a step of forming a conductive layer on the recording area and the amorphous layer may be further performed.

Hereinafter, an information recording medium and a manufacturing method thereof according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings. The width and thickness of the layers or regions shown in the accompanying drawings are somewhat exaggerated for clarity. Like reference numerals in the accompanying drawings indicate like elements.

1 is a cross-sectional view of an information recording medium 100 according to an embodiment of the present invention.

Referring to FIG. 1, the information recording medium 100 may include an underlayer 20 and a recording layer 30 that are sequentially provided on the substrate 10. The base layer 20 will be described later. The recording layer 30 includes a plurality of ferroelectric recording areas 30a separated from each other by at least one inactive area 30b. The ferroelectric recording region 30a is a crystalline region in which information is recorded, for example, PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO. _It may be an area including one of _three . The shape of the ferroelectric recording area 30a may be a cylinder or a square cylinder, but may be other shapes, for example, an annular or line track. Such a plurality of ferroelectric recording areas 30a may be arranged regularly, for example, at equal intervals. When the plurality of ferroelectric recording areas 30a have a cylindrical or square shape, the inactive area 30b may be a continuous area. When the plurality of ferroelectric recording areas 30a are annular or line tracks, the inactive area ( 30b) may be a plurality of areas separated by the ferroelectric recording area 30a. The inactive region 30b is an amorphous nonferroelectric region and does not have information recording characteristics. In the present embodiment, the inactive region 30b includes at least one source material for forming the ferroelectric. For example, the inactive region 30b is one of amorphous PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ as the source material. It may include. In this case, the inactive region 30b may be a single layer structure formed of any one of the above materials. Alternatively, the inactive region 30b may be formed of [PbO and TiO ₂ ] or [PbO, ZrO and TiO ₂ ] or [PbO, LaO and TiO ₂ ] or [PbO and ZrO ₂ ] or [KO and NbO ₂ ] as the source material. Or [LiO and TiO ₂ ] or [LiO and NbO ₂ ] or [BiO and FeO ₂ ]. When the inactive region 30b includes at least two source materials, the source materials may be alternately stacked one or more times to form a multilayer structure. The source materials described above are all amorphous and do not have ferroelectric properties. Although not shown in FIG. 1, a diamond like carbon (DLC) layer may be provided on the recording layer 30, and a lubricant may be coated on the DLC layer.

The underlayer 20 of FIG. 1 may have various configurations as shown in FIGS. 2A to 2C.

Referring to FIG. 2A, the base layer 20a may include an adhesion layer 2 and an electrode layer 4 thereon. The adhesive layer 2 may be, for example, a layer formed of Ti, Zr, TiO ₂ , ZrO ₂ , Hf or HfO ₂ , and the electrode layer 4 may be, for example, Pt, Al, Au, Ag, Cu, Ir, IrO ₂ , SrRuO _It may be a layer formed of ₃ or (La, Sr) CoO, but the present invention is not limited thereto.

Referring to FIG. 2B, the base layer 20b may include an adhesive layer 2, an electrode layer 4, and an intermediate layer 6 that are sequentially stacked. The material of the adhesive layer 2 and the electrode layer 4 may be the same as described with reference to FIG. 2A, and the intermediate layer 6 may be, for example, ZrO ₂ , TiO ₂ , MgO ₂ , SrTiO ₃ , Al ₂ O ₃ , HfO _2. , Nb oxide, SiO ₂ and ZnO ₂ may be a layer made of a dielectric material. This intermediate layer 6 may have a very smooth surface, and may serve to improve deposition characteristics and crystallization characteristics of the ferroelectric source material layer provided thereon.

Referring to FIG. 2C, the base layer 20c may include an electrode layer 4 and a crystal alignment layer 3 under the electrode layer 4 for guiding the crystal alignment direction of the electrode layer 4. A seed layer 1 may be further provided below the layer 3. The crystal alignment layer 3 may be, for example, a Cr layer or an Fe layer, and the seed layer 1 may be, for example, a Ta layer or a Zr layer, but the present invention is not limited thereto. As described above, when the crystal alignment layer 3 is provided, a low cost amorphous substrate can be used as the substrate 10 of FIG.

2A to 2C, the seed layer 1, the adhesive layer 2, the crystal alignment layer 3, and the intermediate layer 6 are optional elements, and the base layers 20a, 20b, and 20c have various configurations. Can be changed.

3 is a cross-sectional view of an information recording medium 100 'according to another embodiment of the present invention.

Referring to Fig. 3, the ferroelectric recording region 30a 'slightly protrudes from the inactive region 30b, and the conductive layer 40 is provided on the inactive region 30b. The conductive layer 40 may serve as a charge source for replenishing charge in the ferroelectric recording region 30a '. The conductive layer 40 is preferably formed of a metal oxide such as indium tin oxide (ITO), SrRuO ₃ , RuO, or the like, but may be formed of a metal or another conductive material. The thickness of the conductive layer 40 is preferably as thin as several nm or less, for example, about 1 to 2 nm. The upper surface of the conductive layer 40 and the upper surface of the ferroelectric recording region 30a 'may have the same height, but in some cases, the height may be slightly different.

Although not shown here, according to another embodiment of the present invention, the conductive layer (Fig. 3) is formed on the ferroelectric recording region 30a and the inactive region 30b of Fig. 1, that is, the entire upper surface of the recording layer 30. A conductive layer having the same function as 40) may be provided.

4A and 4B show a method of manufacturing an information recording medium according to an embodiment of the present invention.

Referring to FIG. 4A, a predetermined base layer 20 is formed on the substrate 10. The base layer 20 may be formed of, for example, one of the structures of FIGS. 2A to 2C. Next, an amorphous source material layer 30 ′ is formed on the underlayer 20. The source material layer 30 ′ may be a layer including a ferroelectric source material, and may be formed by sputtering at room temperature, but may be formed by other methods such as thermal evaporation, It may be formed by chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), pulsed laser deposition (PLD), or the like. The source material layer 30 ′ may be formed in a single layer or a multilayer structure. For example, when the source material layer 30 'has a single layer structure, PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ Can be formed into one. If the source material layer 30 'is formed in a multi-layered structure, PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO by heat treatment And a plurality of material layers forming one of the ferroelectrics of ₃ and BiFeO ₃ . In more detail, the source material layer 30 ′ of the multilayer structure includes a PbO layer and a TiO ₂ layer, a PbO layer, a ZrO layer, and a TiO ₂ layer, or a PbO layer, a LaO layer, and a TiO ₂ layer. Or comprising a PbO layer and a ZrO ₂ layer, comprising a KO layer and a NbO ₂ layer, comprising a LiO and TiO ₂ layer, comprising a LiO and NbO ₂ layer, or comprising a BiO layer and a FeO ₂ layer They may be stacked alternately at least once.

Referring to FIG. 4B, a mask M1 having a hole array is positioned above the source material layer 30 ′. Then, the light L1 is irradiated toward the source material layer 30 ′ above the mask M1. The light L1 may be a laser or other light. Regions of the source material layer 30 ′ located below the holes of the mask M1 are locally heated by the light L1, as a result of which the heated regions are transferred to the crystalline ferroelectric recording region 30a. Is changed. If the source material layer 30 'has a multi-layered structure, the constituent layers of the source material layer 30' may be reacted to form a single layer ferroelectric (ferroelectric recording region 30a) by the heating. A portion of the source material layer 30 ′ that is not irradiated with light L1 and remains in an amorphous / nonferroelectric state may correspond to the inactive region 30b of FIG. 1. The portion of the source material layer 30 ′ remaining in the amorphous / nonferroelectric state and the ferroelectric recording region 30a may be combined to correspond to the recording layer 30 of FIG. 1.

Although not shown, a DLC layer and a lubricant may be sequentially applied onto the ferroelectric recording region 30a and the remaining source material layer 30 '. In addition, before forming the DLC layer, a conductive layer serving as a charge source may be formed on the ferroelectric recording region 30a and the remaining source material layer 30 '.

As described above, according to the embodiment of the present invention, a plurality of crystallized ferroelectric recording regions 30a can be formed by locally heating the amorphous source material layer 30 '. In this case, the crystallized ferroelectric recording area 30a is formed and an inactive area (30b in Fig. 1, 30 'in Fig. 4B) is defined. That is, after forming a template having a hole array, patterning is performed in a very simple manner completely different from the conventional method of filling a ferroelectric into the hole array or directly etching a ferroelectric layer. An information recording medium equivalent to a patterned medium can be embodied. Therefore, by using the present embodiment, a high density (recording density of 1 Tb / in ² or more) information recording medium having excellent uniformity and physical properties can be easily implemented in a relatively simple process, by preventing or minimizing physical and chemical damage of the recording area. Can be.

5A and 5B show a method of manufacturing an information recording medium according to another embodiment of the present invention.

Referring to FIG. 5A, the base layer 20 and the source material layer 30 ′ are formed on the substrate 10 in the same manner as in FIG. 4A. Thereafter, the conductive layer 40 is formed on the source material layer 30 '. The conductive layer 40 may be formed of, for example, a metal oxide such as indium tin oxide (ITO), SrRuO ₃ , RuO, or the like, but may be formed of a metal or another conductive material. The thickness of the conductive layer 40 is preferably as thin as several nm or less, for example, about 1 to 2 nm.

Referring to FIG. 5B, a mask M1 having a hole array is positioned above the conductive layer 40. Then, light L1 is irradiated toward the conductive layer 30 ′ from above the mask M1. Accordingly, regions of the conductive layer 40 and the source material layer 30 ′ disposed under the holes of the mask M1 are locally heated by the light L1. At this time, since the thickness of the conductive layer 40 is several nm or less, heating of the source material layer 30 'by light L1 and reaction of the heated source material layer 30' and the conductive layer 40 It may be easy. At this time, a part or all of the heated conductive layer 40 may diffuse into the heated source material layer 30 'beneath it, and the heated regions may become a ferroelectric recording region 30a' through a crystallization process. Can be. The portion of the source material layer 30 'that is not heated is left in an amorphous / nonferroelectric state, and a conductive layer 40 remains on the upper surface.

The above-described manufacturing methods of the information recording medium can be modified in various ways. For example, the mask M1 in FIGS. 4B and 5B may be replaced with a concentric diffraction plate. By using the concentric diffraction plate, it is possible to simultaneously irradiate a plurality of track-shaped light concentric to the disk-type substrate. In this case, a track-type ferroelectric recording region can be easily formed on the disk type substrate. Concentric diffraction plate is well known, the drawings and detailed description thereof will be omitted. In addition, when using an E-beam as a heat source, a local heating process may be performed on the source material layer 30 ′ without using a mask M1 or a concentric diffraction plate. In addition, other than light or E-beam may be used as a means for heating the source material layer 30 ′. For example, the resistive probe P1 as shown in FIG. 6 may be used as the heating means.

Referring to FIG. 6, a portion of the tip T1 of the resistive probe P1 is positioned in a predetermined region of the source material layer 30 ′, and the predetermined region is heated by heat generated from the tip T1. In this way, a plurality of regions of the source material layer 30 'can be changed into the ferroelectric recording region 30a. In this case, by using a plurality of resistive probe arrays, a plurality of regions may be heated at the same time.

7 shows an information storage device including a ferroelectric recording medium according to an embodiment of the present invention.

Referring to FIG. 7, the information storage apparatus according to the embodiment of the present invention includes a ferroelectric information recording medium 100a. The information recording medium 100a may be a disk type that rotates, and may have the same structure as that of FIG. 1 or 3 in cross section, or may have a structure modified therefrom. An electric field recording / reproducing head 200 is provided for recording information on the information recording medium 100a and reproducing the information from the information recording medium 100a. The electric field recording / reproducing head 200 may rotate and float from the surface of the information recording medium 100a while being attached to the suspension 300 at the end of the swing arm 400. Unexplained reference numeral 500 denotes a voice coil motor (VCM) for rotating the swing arm 300. According to this embodiment of the present invention, it is possible to implement an information storage device having a high recording density of 1Tb / in ² or more while driving stably.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, in the embodiment of the present invention, the amorphous source material layer 30 'may be a source material layer other than the ferroelectric source material layer. In this case, the recording area 30a is also a recording area other than the ferroelectric area. Can be. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

1 is a cross-sectional view of an information recording medium according to an embodiment of the present invention.

2A to 2C are cross-sectional views showing various configurations of the underlying layer provided in the information recording medium according to the embodiment of the present invention.

3 is a cross-sectional view of an information recording medium according to another embodiment of the present invention.

4A and 4B are sectional views showing the manufacturing method of the information recording medium according to the embodiment of the present invention.

5A and 5B are cross-sectional views showing a method of manufacturing an information recording medium according to another embodiment of the present invention.

6 is a cross-sectional view showing a method of manufacturing an information recording medium according to another embodiment of the present invention.

7 is a perspective view of an information storage device according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1 seed layer 2 adhesive layer

3: crystal orientation layer 4: electrode layer

6: intermediate layer 10: substrate

20, 20a to 20c: base layer 30: recording layer

30a, 30a ': recording area 30b: inactive area

30 ': source material layer 40: conductive layer

100, 100 ', 100a: information recording medium 200: electric field recording / playback head

300: suspension 400: swing arm

500: VCM L1: Light

M1: Mask P1: Resistive Probe

T1: tip

Claims (15)

A recording layer having a plurality of recording areas separated from each other by an inactive area, The recording area is a crystalline ferroelectric area, And the inactive region is an amorphous non-ferroelectric region containing a ferroelectric source material. The method of claim 1, The source material is one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO ₃ and BiFeO ₃ . The method of claim 1, The source material comprises PbO and TiO _2, or PbO, including ZrO, and TiO _2, or include PbO, LaO and TiO _2, or include PbO, and ZrO _2, or including a KO and NbO _2, or LiO and An information recording medium comprising TiO ₂ , comprising LiO and NbO ₂ , or comprising BiO and FeO ₂ . The method of claim 1, And the recording area is a crystalline area including one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ . The method of claim 1, And an conductive layer on the inactive area. The method of claim 1, And a conductive layer on the recording layer. Forming an amorphous layer; And And changing a plurality of areas spaced apart from each other in the amorphous layer into a crystalline recording area. The method of claim 7, wherein The amorphous layer includes a ferroelectric source material, And the recording area is a ferroelectric area. The method according to claim 7 or 8, Wherein the amorphous layer is formed of one of PbTiO ₃ , Pb (Zr, Ti) O ₃ , (Pb, La) TiO ₃ , PbZrO ₃ , KNbO ₃ , LiTaO ₃ , LiNbO _3, and BiFeO ₃ . The method according to claim 7 or 8, The amorphous layer is formed in a multilayer structure, The multilayer structure includes a PbO layer and a TiO ₂ layer, includes a PbO layer, a ZrO layer and a TiO ₂ layer, includes a PbO layer, a LaO layer and a TiO ₂ layer, includes a PbO layer and a ZrO ₂ layer, A method of manufacturing an information recording medium comprising a KO layer and an NbO ₂ layer, comprising a LiO and TiO ₂ layer, comprising a LiO and NbO ₂ layer, or a BiO layer and a FeO ₂ layer. The method according to claim 7 or 8, Changing the plurality of areas of the amorphous layer to the recording area, And heating said plurality of areas. The method of claim 11, And the plurality of regions are heated by one of light, an E-beam, and a resistive probe. The method according to claim 7 or 8, Between forming the amorphous layer and changing the plurality of areas of the amorphous layer to the recording area, And a conductive layer formed on said amorphous layer. The method of claim 13, When changing the plurality of areas of the amorphous layer to the recording area, And at least a portion of the conductive layer located on each of the plurality of areas is diffused into the corresponding plurality of areas. The method according to claim 7 or 8, After changing the plurality of areas of the amorphous layer to the recording area, And forming a conductive layer on the recording area and the amorphous layer.

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