JPH041950A - Recording medium and its manufacturing method, information processing method, information processing device - Google Patents

Abstract

PURPOSE:To obtain the recording medium which can lower the error rate of read data and allows high-speed reproducing by specifying surface ruggedness and smooth surface. CONSTITUTION:The recording medium has a substrate 101, an electrode layer 102 having the smooth surface and a recording layer 103. The electrode substrate 101 is provided with the smooth surface having <=1nm surface ruggedness and >=1mum square size. This method includes the stage for forming the electrode layer contg. an electrode material on a base material having preferably <=1nm surface ruggedness and >=1mum square size and the stage for separating the electrode layer from the base material. The recording medium which lowers the error rate of the read data and allows the high-speed reproducing is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a recording medium, an electrode substrate, a manufacturing method thereof, and a recording device and a reproducing device that perform recording and reproduction using a probe electrode using such a recording medium. , an information processing device including a recording and reproducing device, a recording method, a recording and reproducing method,
The present invention relates to an information processing method including a recording/reproducing/erasing method.

[Prior Art] In recent years, the use of memory materials has become the core of the electronics industry, such as computers and related equipment, video disks, digital audio disks, etc.
The development of these materials is also progressing very actively. The performance required of memory materials varies depending on the application, but for boat fishing, the following are: - High density and large storage capacity, - Fast response speed for recording and playback, - Low power consumption, - High productivity (, Prices are low, etc.

Until now, semiconductor memory and magnetic memory were mainly made of magnetic materials and semiconductors, but with the recent advances in laser technology, inexpensive and high-density optical memory using organic thin films such as organic dyes and photopolymers has been developed. recording media have appeared.

On the other hand, recently, a scanning tunneling microscope (hereinafter abbreviated as STM) that can directly observe the electronic structure of surface atoms of conductors has been developed [G, B1nn1g etal, Phys, Re
v, Lett, 49.57 (1982)], single crystal,
It is now possible to measure real space images with high resolution regardless of the amorphous material, and it also has the advantage of being able to observe with low power without damaging the sample due to current, and can also operate in the atmosphere.
Since it can be used for various materials, it is expected to have a wide range of applications.

STM uses the fact that when a voltage is applied between a metal probe (probe electrode) and a conductive substance to bring them close to a distance of about 1 nm, a tunnel current flows. This current is very sensitive to changes in distance between the two. By scanning the probe while keeping the tunnel current constant, it is possible to read various information about the entire electron cloud in real space. At this time, the resolution in the in-plane direction is approximately 0.1 nm.

Therefore, by applying the principle of STM, it is possible to sufficiently perform high-density recording and reproduction on the atomic order (sub-nanometer). For example, JP-A-61-8053
In the recording/reproducing device disclosed in No. 6, atomic particles adsorbed on the surface of the medium are removed by an electron beam or the like.
Writing is performed and this data is reproduced by STM.

A method has been proposed in which STM recording and reproducing is performed using a thin film layer of a material that has a memory effect on voltage and current switching characteristics, such as a π-electron organic compound or a chalcogen compound, as the recording layer. JP-A-63-161'
No. 552, JP-A-63-161553].

According to the publication No. Hoshin, it is possible to record and reproduce a large capacity with a recording bit size of 10 nm Lf, 1012 bits/cm2.

[Problems to be Solved by the Invention] FIG. 7 shows a configuration example of an information processing device to which S'TM is applied. This will be explained below according to the drawings.

101 is a substrate, 102 is a metal electrode layer, and 103 is a recording layer. 201 is an XY stage, 202 is a probe electrode, 203 is a support for the probe electrode, 2C) 4 is a Z-axis near actuator that drives the probe electrode in the Z direction, 2
05 and 206 are linear actuators that drive the XY stage in the X and Y directions, respectively, and 207 is a pulse voltage circuit.

301 is an amplifier that detects a tunnel current flowing from the probe electrode 202 to the electrode layer 102 via the recording layer 103. 302 is a probe electrode 20 that detects changes in tunnel current.
2 and a logarithmic compressor for converting into a value proportional to the gap distance between the recording layer 103, and 303 a low-pass filter for extracting the surface unevenness component of the recording layer 103. 304 is an error amplifier that detects an error between the reference voltage VIIEF and the output of the low-pass filter 303; 305 is a driver that drives the Z-axis near actuator 204; 306 is a drive circuit that controls the position of the XY stage 201 6
307 is a high-pass filter that separates data components.

FIG. 8 shows a cross section of a conventional recording medium and a probe electrode 202.
Shows the tip of.

401 is a data bit recorded in the recording layer 103, 40
2 are crystal grains formed when the electrode layer 102 was formed on the substrate 101. The size of the crystal grains 402 is the same as that of the electrode layer 1.
When a normal vacuum evaporation method, sputtering method, etc. is used as a manufacturing method for 02, the thickness is about 30 to 50 nm.

The gap between the probe electrode 202 and the recording layer 103 can be kept constant by the circuit configuration shown in FIG. That is, the tunnel current flowing between the probe electrode 202 and the recording layer 103 is detected, and after passing through the logarithmic compressor 302 and the low-pass filter 303, this value is compared with a reference voltage, and when this comparison value approaches zero ( By controlling the biaxial linear actuator 204 that supports the probe electrode 202 in this manner, the gap between the probe electrode 202 and the recording layer 103 can be made constant.

Further, by driving the XY stage 201, the probe electrode 202 traces the surface of the recording medium, and data on the recording layer 103 can be detected by separating the high frequency component of the signal at the 0 point.

FIG. 9 shows the signal strength spectrum with respect to the frequency of the signal at the 0 point at this time.

Signals with frequency components below fo are due to gentle undulations of the medium due to warping, distortion, etc. of the substrate 101. The signal centered on fl is due to the unevenness of the surface of the recording N103, and is mainly due to the crystal grains 402 generated during the formation of the electrode material. f2 is the carrier wave component of the recording data, 403
is the data signal band. f3 is an atom of the recording layer 103,
It is a signal component resulting from molecular arrangement.

When the recording medium shown in the conventional example was used, there were the following problems.

In order to perform high-density recording by taking advantage of the high resolution that is a feature of STM, the data signal band 403 must be placed between fl and f3. In this case, a high-pass filter 307 with a cutoff frequency fc is used to separate the data components. However, the base of the signal component of fl is in the data signal band 4.
It overlaps with 03. This means that the signal component of f is the electrode layer 1
This is due to the crystal grains 402 of No. 02, and the data recording size and bit interval are close to each other, 1 to 10 nm, compared to 30 to 50 nm of the crystal grains 402.

As a result, the S/N ratio of data reproduction decreases, and the error rate of read data becomes extremely high.

Therefore, in view of the above problems, an object of the present invention is to achieve a high S/N ratio.
The object of the present invention is to provide a recording medium that enables high-speed reproduction, an electrode substrate for use in such a recording medium, an information processing apparatus having such a recording medium, and an information processing method.

Another object of the present invention is to provide a recording medium in which the error rate of read data is significantly reduced by sufficiently improving the S/N ratio, an electrode substrate for use in such a recording medium, and an information processing apparatus using such a recording medium. , to provide an information processing method.

[Means and effects for solving the problems] The above objects are achieved by the present invention as described below.

That is, the present invention is an electrode substrate characterized by having a smooth surface having surface irregularities of 1 nm or less and a size of 1 μm or more; A method for manufacturing an electrode substrate, comprising the steps of forming an electrode layer containing an electrode material on a base material having a smooth surface with a diameter of 1 μm or more, and separating the electrode layer from the base material, and The present invention is a recording medium characterized by having a smooth surface having surface irregularities of 1 nm or less and a size of 1 μm or more; It is characterized by comprising the steps of forming an electrode layer containing an electrode material on a base material having a smooth surface that is larger than ILLm, separating the electrode layer from the base material, and forming a recording layer on the electrode layer. A method for manufacturing a recording medium, and the present invention also provides a recording medium having a smooth surface with surface irregularities of 1 nm or less and a size of 1 μm or more, and a conductive material disposed close to the recording medium. An information processing device characterized by comprising a probe and a recording pulse voltage application circuit, and the present invention also provides a recording medium having a smooth surface with surface irregularities of 1 nm or less and a size of 1 μm or more. , an information processing device characterized by comprising a conductive probe disposed close to the recording medium, a recording pulse voltage application circuit, and a reproduction bias voltage application circuit; A recording medium having a smooth surface with a diameter of 1 nm or less and a size of 1 μm or more, on which information is recorded, a conductive probe disposed close to the recording medium, and a reproduction bias voltage application circuit. The present invention also provides a recording medium having a recording layer on an electrode substrate, a smooth surface having surface irregularities of 1 nm or less, and a size of 1 μm or more. This is an information processing method characterized by recording information by bringing conductive probes close to each other and applying a pulse voltage between an electrode substrate and the conductive probe. A conductive probe is brought close to a recording medium having a smooth surface with surface irregularities of 1 nm or less and a size of 1 μm or more, and a pulse voltage is applied between the electrode substrate and the conductive probe to read information. An information processing method characterized by performing recording and reproducing recorded information by applying a bias voltage, and the present invention also provides an information processing method that has a recording layer on an electrode substrate, and has a surface unevenness of 1 nm or less. , a conductive probe is brought close to a recording medium having a smooth surface with a diameter of 1 μm or more, a first pulse voltage is applied between the electrode substrate and the conductive probe to record information, and a bias voltage is applied. This information processing method is characterized in that recorded information is reproduced by applying a pulse voltage, and recorded information is erased by further applying a second pulse voltage.

By providing a recording medium having a smooth surface according to the present invention, it has become possible to fully utilize the functions of an information processing device to which the principles of STM are applied.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows a cross-sectional view of a recording medium according to the invention. 101
102 is a substrate, 102 is an electrode layer having a smooth surface, and 103 is a recording layer.

FIG. 3 shows cross-sectional views at each step of producing a recording medium according to the present invention.

In FIG. 3(a), first, a smooth substrate 11 is prepared. This smooth substrate needs to have a smooth surface with surface irregularities of 1 nm or less, preferably 1 μm or more.

Surface unevenness is measured using AFM (Atomic), which brings the tip of a microprobe close to the surface of a sample substrate, measures the atomic force acting between the atom at the tip of the microprobe and the atom on the surface of the sample substrate, and observes the shape of the sample surface. -Force-Micro
This can be done using a technique called ``scopy''.

When such an AFM is used, the surface shape of a sample can be measured with resolution on the atomic order, regardless of whether the sample is conductive or insulative. The present inventors evaluated the surfaces of various materials using AFM and found that the following materials were suitable as the smooth substrate 11 in the present invention.

■Crystal cleavage plane: The crystal cleavage plane can easily obtain an extremely smooth surface, and mica,
MgO, Tic, Si, HOPG.

etc.

(2) Molten glass surface: Examples include float glass, #7059 Fusion fused quartz 5, and the like.

When the surface shape of the above material was measured by AFM, it was found that 1
All surface irregularities were 1 nm or less in the 0 μm opening region. In particular, mica fold-opened surfaces have few steps in the lattice plane that occur during cleavage, and have a spatial frequency of 3.5 mm over a large area (km).
The unevenness of 3x l O'cm-' or less is 1 nm or less, and is suitable as a smooth substrate for use in the present invention.

Next, as shown in FIG. 3(b), an electrode layer 102 is formed on the smooth substrate 11. The electrode layer 102 according to the present invention is preferably made of a material that has high conductivity and does not have good adhesion to the smooth substrate 11. For example, Au, Ag, Pt
, noble metals such as Pd, alloys such as Au-Pd and Pt-Pd, and laminated films thereof. Conventionally known thin film forming techniques are sufficient for forming electrodes using such materials.

Next, as shown in FIG. 3(C), an adhesive layer 12 is formed on the electrode layer 102. The adhesive layer 12 according to the present invention is preferably a solvent-free adhesive that does not have volumetric shrinkage, and examples include insulating adhesives such as epoxy resin-based and α-cyanoacrylate-based adhesives, and conductive adhesives such as Evotec Silver series. It will be done.

Next, as shown in FIG. 3(d), the substrate 10 is placed on the adhesive layer 12.
Attach 1. In this step, when the substrate 101 and the electrode layer 102 are directly bonded, for example, by eutectic bonding, electroforming, etc., the adhesive layer 12 can be omitted. When using the adhesive layer 12 as the substrate 101 according to the present invention, metal,
Any material such as glass, ceramics, or plastic material can be used. Further, when directly bonding to the substrate 101, a relatively smooth material is preferable. Further, if the electrode layer 102 is thick, the substrate 101 can be omitted.

Next, as shown in FIG. 3(e), by peeling off the smooth substrate 11 from the electrode layer 102, a smooth electrode substrate having a smooth surface of 1 μm μm with surface irregularities of 1 nm or less can be formed.

Next, as shown in FIG. 3(f), the electrode layer 1 of the smooth electrode substrate is
A recording medium is obtained by forming a recording layer 103 on 02.

The recording layer 103 is made of a material having a memory switching phenomenon (electrical memory effect) in current-voltage characteristics, such as molecules having both a group having a π electron level and a group having only a 0 electron level, on an electrode. It becomes possible to use a stacked organic monomolecular film or a cumulative film thereof. The electrical memory effect differs depending on the state in which a thin film such as the organic monomolecular film or its cumulative film is placed between a pair of electrodes.
States exhibiting more than one conductivity (Figure 11: ON state, OFF state)
By applying a voltage exceeding a threshold that can cause a transition to a low resistance state (ON state) and a high resistance state (OFF state), it is possible to reversibly transition (switch) to a low resistance state (ON state) and a high resistance state (OFF state). Further, each state can be maintained (memory) without applying a voltage.

Since most organic materials generally exhibit insulating or semi-insulating properties, there is a wide variety of organic materials having a group having a π-electron level that can be applied to the present invention. Structures of dyes having a π-electron system suitable for the present invention include, for example, phthalocyanine, dyes having a porphyrin skeleton such as tetraphenylporphyrin, azulene dyes having squarylium groups and croconic methine groups as bonding chains, quinoline, benzothiazole, Cyanine-based similar dyes, such as benzoxazole, in which two nitrogen-containing heterocycles are bonded by a squarylium group and a croconic methine group, or cyanine dyes, fused polycyclic aromatics such as anthracene and pyrene, and aromatic and heterocyclic compounds. chain compounds and diacetylene group polymers,
Further examples include derivatives of tetracyanoquinodimethane or tetrathiafulvalene, analogs thereof and charge transfer complexes thereof, and metal complex compounds such as ferrocene and trisbipyridine ruthenium complexes.

Examples of polymeric materials suitable for the present invention include biopolymers such as addition polymers such as polyacrylic acid derivatives, condensation polymers such as polyimide, and ring-opening polymers such as nylon.

Regarding the formation of the recording layer 103, specifically, it is possible to apply a vapor deposition method, a cluster ion beam method, etc.
Among the known prior art techniques, the LB method is highly preferred due to its controllability, ease of use, and reproducibility.

According to this LB method, a monomolecular film of an organic compound having a hydrophobic site and a hydrophilic site in one molecule or a cumulative film thereof can be easily formed on a substrate, and the thickness is on the order of a molecule. , and can stably supply a uniform and homogeneous ultra-thin organic film over a large area.

The LB method is a molecule with a structure that has a hydrophilic site and a hydrophobic site, and when the balance between the two (amphiphilic balance) is maintained appropriately, the molecule lowers the hydrophilic group on the water surface. This is a method of forming a monomolecular film or a cumulative film thereof by utilizing the fact that the monomolecular layer becomes a monomolecular layer.

Examples of the group constituting the hydrophobic moiety include various hydrophobic groups such as generally widely known saturated and unsaturated hydrocarbon groups, fused polycyclic aromatic groups, and chain polycyclic phenyl groups.

These each constitute a hydrophobic site singly or in combination.

On the other hand, the most typical constituent elements of the hydrophilic site are, for example, carboxyl groups, ester groups, acid amide groups, imide groups, hydroxyl groups, and even amino groups (1, 2,
Examples include hydrophilic groups such as tertiary and quaternary).

Organic molecules containing these hydrophobic groups and hydrophilic groups in a well-balanced manner are capable of forming a monomolecular film on the water surface, and are extremely suitable materials for the present invention.

Although the electric memory effect of these compounds having the π electron level has been observed with a film thickness of several nanometers or less, it is preferable to have a thickness of 5 to 300 nanometers from the viewpoint of film formability and uniformity.

FIG. 2 shows the frequency spectrum of the zero point signal when the recording medium according to the present invention is used in the information processing apparatus shown in FIG. 7.

The signals with frequency components below f are due to gentle undulations of the medium due to warping, distortion, etc. of the substrate 101. f2 is a carrier wave component of recording data, and 403 indicates a data signal band. f3 is a signal component generated from the arrangement of atoms and molecules in the recording layer 103.

The signal centered on fl is a result of slight irregularities on the surface of the base material being transferred to the surface of the electrode layer 102, and these irregularities are created to be equal to or smaller than the data recording signal. This change in unevenness is 1 in recording and reproducing using STM.
nm or less. Further, in the recording medium according to the present invention, the size of the smooth surface of the recording layer 103 is 1 μm or more.

This provides the following effects.

(1) The signal component element 1 and the data signal band 403 do not overlap due to the unevenness of the surface of the recording layer 103, and there is no reduction in S/N due to the spread of the spectrum of fl. That is, the data error rate can be reduced.

(2) Since there is no unevenness on the surface of the recording layer 103, the recording layer 10
The displacement of the probe electrode 202 along the Z axis is small when performing XY constant scanning without keeping the gap between the surface of the probe electrode 202 and the surface of the probe electrode 3 constant. Therefore, the XY stage 201 can be
can be driven.

(3) Since there is no unevenness on the surface of the recording layer 103, the tip of the probe electrode 202, that is, the position of the tip atom through which the tunneling current flows, can be stably selected. In addition, the probe electrode 202 as seen on the uneven surface of the recording layer 103
The so-called ghost phenomenon in which a tunnel current flows between the plurality of atoms and the recording layer 103 is eliminated.

[Example] Example 1 Example 1 of the present invention will be described with reference to FIGS. 3(a) to (fl).

First, as shown in FIG. 3(a), a mica plate is cleaved in the atmosphere to form a smooth substrate 11. Subsequently, as shown in FIG. 3(b), a gold film is formed on the smooth substrate 11 by vacuum evaporation to form an electrode layer 102. The electrode layer 102 maintains the substrate temperature at room temperature, the deposition rate is 10 persons/sec, and the ultimate pressure is 2.
The test was carried out under the conditions of X 10-' Torr and film thickness of 2,000 people. Subsequently, as shown in FIG. 3(C), the adhesive layer 12
(High Temp HT-10 manufactured by Konishi) is applied onto the electrode layer 102.

Subsequently, as shown in FIG. 3(d), the substrate 101 is attached onto the adhesive layer 12. The substrate 101 is bonded with a pressure of 5k.
g/cm2, temperature of 200°C, and curing time of 1 hour. Subsequently, as shown in FIG. 3(e), the smooth substrate 11
is peeled off from the electrode layer 102, and the substrate 101 and adhesive layer 12 are separated.
A smooth electrode substrate consisting of the electrode layer 102 was obtained. When the surface of the thus obtained smooth electrode substrate was observed by STM, the surface unevenness was 1 nm or less at 10 ILm opening.

Next, as shown in FIG. 3(f), four electrodes are placed on this smooth electrode substrate.
A polyimide LB film was formed as a recording layer 103. A method for forming the recording layer 103 using a polyimide LB film will be described below.

After dissolving the polyamic acid shown in formula (1) in a mixed solvent of N,N''-dimethylacetamide-benzene (1:IV/V) (monomer equivalent concentration 1 x 10-''M), separately prepared N , and a 1X10-''M solution of N-dimethyloctadecylamine in the same solvent were mixed at a ratio of 1:2 (V/V) to prepare a polyamic acid octadecylamine salt solution shown in formula (2).

This solution was spread on an aqueous phase consisting of pure water at a water temperature of 20°C to form a monomolecular film on the water surface. After evaporating the solvent, the surface pressure was increased to 25 mN/m. While keeping the surface pressure constant, move the above-mentioned smooth electrode substrate across the water surface at a speed of 5 mm/
After gently dipping at a speed of 5 mm/min, the film was gently pulled up at a rate of 5 mm/min to produce a two-layer Y-type monomolecular cumulative film. These operations were repeated to form a four-layer monomolecular cumulative film of polyamic acid octadecylamine salt. Next, this substrate was baked under reduced pressure (~1 mmHg) at 300° C. for 10 minutes to imidize the polyamic acid octadecylamine salt (Formula 3) to obtain a four-layer polyimide monomolecular cumulative film.

Next, using the recording medium produced by the method described above, the surface shape was examined using the information processing apparatus shown in FIG. 7, and it was found that the surface of the recording medium reflected the smooth surface of the electrode.
The surface unevenness at the opening was 1 layer m or less. Next, we conducted recording/playback experiments.

A platinum/rhodium probe electrode 202 was used as the probe electrode 202. This probe electrode 202 uses a piezoelectric element to control the distance (Z) from the surface of the recording layer 103 so that the current is kept constant.
) is controlled by fine movements. Furthermore, the linear actuators 204, 205, and 206 keep the distance 2 constant,
It is designed to allow fine movement control in the in-plane (X, Y) directions as well.

Further, the probe electrode 202 can directly perform recording, reproduction, and erasing. Further, the recording medium is placed on a high-precision XY stage 201 and can be moved to any position.

A recording medium having a recording layer 103 in which the four polyimide layers described above were accumulated was placed on an XY stage 201. Next, between the probe electrode 202 and the electrode layer 102 of the recording medium, +
A voltage of 1.5 cm was applied, and the distance (Z) between the probe electrode 202 and the surface of the recording layer 103 was adjusted while monitoring the current.

At this time, the probe current Ip for controlling the distance Z between the probe electrode 202 and the surface of the recording layer 103 is set to 10-"A≧
It was set so that Ip≧10−”A.

Next, while scanning the probe electrode 202 over the recording layer 103, information was recorded at a pitch of 100 people. Recording of such information is performed with the probe electrode 202 on the + side and the electrode layer 10
With 2 on one side, the electric memory material (polyimide LB film 4 layers) changes to a low resistance state (ON state).
pulse voltage) was applied. After that, the probe electrode 202
was returned to the recording start point, and the recording layer 103 was scanned again. At this time, when reading the record, adjustment was made so that Z=constant. As a result, a probe current of about 10 nA flowed in the data bit 401, indicating that it was in the ON state.

In addition, as a result of setting the probe voltage to 10 mm (second pulse voltage) exceeding the threshold voltage V thOF at which the electric memory material changes from the ON state to the OFF state and tracing the recording position again, all recording states were is erased and turned OFF.
It was also confirmed that the state had changed. Furthermore, when the error rate of the read data was examined while keeping the reading speed constant, it was found that while it was 10-4 in the conventional example, it was possible to significantly reduce it to 10-7 in this embodiment.

Example 2 Example 2 of the present invention will be described with reference to FIGS. 4(a) to (e). First, as shown in FIG. 4(a), a mica plate is cleaved in the atmosphere to form a smooth substrate 21. Next, Figure 4 (b
), a gold film is formed on a smooth substrate 21 by vacuum evaporation to form an electrode layer 102. The electrode layer 102 was formed under the following conditions: the substrate temperature was kept at room temperature, the deposition rate was 10 people/sec, the ultimate pressure was 2×10-'Torr, and the film thickness was 5000 people. Next, as shown in FIG. 4(c), a Si wafer is heated as a substrate 101 using a heater and kept at a constant temperature, and then an electrode layer 102 formed on the smooth substrate 21 is heated.
The electrode layer 102 and the substrate 101 are eutectically bonded by rubbing the surface of the substrate 101 against the substrate 101.The bonding is performed under the conditions that the substrate temperature is kept at 400'C, the pressure is 2 kg/cm2, and the holding time is 1 minute. Subsequently, as shown in FIG. 4(d), the smooth substrate 21 was peeled off from the electrode layer 102 to obtain a smooth electrode substrate consisting of the substrate 101 and the electrode layer 102.

When the surface of the thus obtained smooth electrode substrate was observed by STM, the surface unevenness was 1 nm at a 10 μm opening.
It was below.

Next, as shown in FIG. 4(e), a four-layer polyimide LB film was formed on this smooth electrode substrate to form a recording layer 103.

Next, using the recording medium produced by the method described above, the surface shape was examined using the information processing apparatus shown in FIG. 7, and the surface shape of the recording medium reflected the smooth surface of the electrode.
The surface unevenness at the μm opening was 1 nm or less. Next, an experiment of recording, reproducing, and erasing was conducted, and it was confirmed that recording, reproducing, and erasing could be performed in the same manner as in Example 1.

Example 3 Example 3 of the present invention will be described with reference to FIGS. 5(a) to (e). First, as shown in FIG. 5(a), a mica plate is cleaved in the atmosphere to form a smooth substrate 31. Next, Figure 5 (b
), A is deposited on the smooth substrate 31 by vacuum evaporation.
The electrode layer 102 is formed by depositing u-F'd. The electrode layer 102 maintains the substrate temperature at room temperature, and the deposition rate is 10 people/s.
e c, ultimate pressure 2 x 10-'T o r r,
The test was conducted under the condition that the film thickness was 1000. Subsequently, as shown in FIG. 5(c), nickel is formed on the electrode layer 102 by electroforming to form the substrate 101. The electroforming was carried out using a Watt bath at a temperature of 50°C, a current density of 0.06 A/cm", and an electroforming time of 2 hours to obtain a thickness of 1100 tL. Subsequently, as shown in Fig. 5(d). As shown in FIG. 2, the smooth substrate 31 was peeled off from the electrode layer 102 to obtain a smooth electrode substrate consisting of the substrate 101 and the electrode 102.

As a result of observing the surface of the thus obtained smooth electrode substrate by STM, the surface unevenness was 1 nm or less at a 10 μm opening.

Next, as shown in FIG. 5(e), four electrodes were placed on the smooth electrode substrate.
A polyimide LB film was formed as a recording layer 103.

Next, using the recording medium produced by the method described above, the surface shape was examined using the information processing apparatus shown in FIG. 7, and it was found that the surface of the recording medium reflected the smooth surface of the electrode,
The surface unevenness at the m-port was 1 nm or less. Next, an experiment of recording, reproducing, and erasing was conducted, and it was confirmed that recording, reproducing, and erasing could be performed in the same manner as in Example 1.

Example 4 Example 4 of the present invention will be described with reference to FIGS. 6(a) to (e). First, as shown in FIG. 6(a), a substrate 101 is made of cleaned fused silica. Subsequently, as shown in FIG. 6(b), a gold film is deposited on the substrate 101 by vacuum evaporation to form an electrode layer 102. The electrode layer 102 was formed by keeping the substrate electrode at room temperature, at a deposition rate of 10 persons/sec, at an ultimate pressure of 2 X I O-'T or r, and at a film thickness of 5000 persons.
The test was carried out under the conditions of 50 Cr sublayers. Next, Figure 6 (c
), a mica plate cleaved in the atmosphere is used as a smooth substrate 41, placed on the electrode layer 102, and pressed. The press was operated in a nitrogen atmosphere with a pressure of 10 kg/cm" and a temperature of 5.
The test was carried out at 00°C for 1 hour. Subsequently, as shown in FIG. 6(d), the smooth substrate 41 was peeled off from the electrode layer 102, thereby obtaining a smooth electrode substrate consisting of the electrode layer 102 and the substrate 101.

When the surface of the thus obtained smooth electrode was observed by STM, the surface unevenness was 1 nm or less at a 10 μm opening.

Next, as shown in FIG. 6(e), a four-layer polyimide LB film was formed on this smooth electrode substrate to form a recording layer 103.

Next, using the recording medium produced by the method described above, the surface shape was examined using the information processing apparatus shown in FIG. 7, and it was found that the surface of the recording medium reflected the smooth surface of the electrode,
The surface unevenness at the opening was 1 layer m or less. Next, an experiment of recording, reproducing, and erasing was conducted, and it was confirmed that recording, reproducing, and erasing could be performed in the same manner as in Example 1.

Example 5 The same as Example 1 except that the gold vapor deposition was changed to Pct and the recording layer 103 was changed from polyimide to a four-layer LB film of squarylium-bis-6-octyl azulene (hereinafter abbreviated as 5OAZ). A recording medium was formed in exactly the same manner as in Example 1. A method for forming the recording layer 103 using 5OAZ will be described below.

First, a benzene solution in which 5OAZ was dissolved at a concentration of 0.2 mg/mff was spread on an aqueous phase at 20° C. to form a monomolecular film on the water surface. After waiting for the solvent to evaporate, the surface pressure of the monomolecular film was increased to 20 mN/m, and while this was kept constant, the smooth electrode substrate was gently immersed at a speed of 3 mm/min across the water surface.・Pull up,
A two-layer cumulative film of 5OAZ monolayer was formed on a smooth electrode substrate.

Next, using the recording medium produced by the method described above, the surface shape was examined using the information processing apparatus shown in FIG. 7, and it was found that the surface of the recording medium reflected the smooth surface of the electrode,
The surface unevenness at the m-port was 1 nm or less. Next, an experiment of recording, reproducing, and erasing was conducted, and it was confirmed that recording, reproducing, and erasing could be performed in the same manner as in Example 1.

[Effects of the Invention] As explained above, according to the recording medium of the present invention, by transferring the surface shape of a smooth substrate, it is possible to form a recording medium having a surface with surface irregularities of less than 1 nm.

Furthermore, the recording medium according to the present invention has the following features: (1) Since the surface shape of the base material can be transferred, it is possible to form a smooth surface anywhere on the substrate, and it is also possible to form reference markers and the like at the same time.

(2) Since the electrode layer can be formed on the base material and then attached to the substrate, the substrate can be made of any material and in any form. For example, a write and read control circuit is built into a Si chip, and the recording medium of the present invention is formed using this chip as a substrate. This results in
A recording medium in which a write/read control circuit and a recording layer are integrally formed can be provided.

Applying the latest micromechanics technology, 5chip
A recording medium with a fine movement mechanism can also be obtained by incorporating a drive actuator thereon and providing the electrode layer of the present invention on this actuator.

Furthermore, if such a recording medium is used, the error rate of read data can be significantly reduced, and high-speed reproduction becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a recording medium used in the present invention, FIG. 2 is a diagram of the frequency spectrum of the reproduced signal of the present invention, and FIGS. 3 to 6 are manufacturing process diagrams for each embodiment. Fig. 7 is a configuration diagram of an information processing device applying STM, Fig. 8 is a schematic cross-sectional view of a conventional recording medium, Fig. 9 is a diagram of the frequency spectrum of a conventional reproduction signal, and Fig. 1
FIG. 0 is a waveform diagram of a pulse voltage applied when recording on the recording medium of the present invention, and FIG. 11 is a current-voltage characteristic graph. 101: Substrate 102: Electrode layer 103: Recording layer 11. 21, 31, 41: Smooth substrate, Figure 1 Question ■ - Figure 4 Figure 8 Zhousao □ 8 Terama Figure 10

Claims (48)

[Claims] (1) Surface unevenness is 1 nm or less, and the size is 1 μm□
An electrode substrate having a smooth surface as described above. (2) Surface unevenness is 1 nm or less, and the size is 1 μm□
A method for manufacturing an electrode substrate, comprising the steps of forming an electrode layer containing an electrode material on a base material having a smooth surface as described above, and separating the electrode layer from the base material. (3) The method for manufacturing an electrode substrate according to claim (2), characterized in that a crystal substrate whose main surface is cleaved is used as the base material. (4) The method for manufacturing an electrode substrate according to claim (2), characterized in that glass whose main surface is formed by melting is used as the base material. (5) The method for manufacturing an electrode substrate according to claim (2), wherein the electrode material is a noble metal or an alloy of noble metals. (6) Surface unevenness is 1 nm or less, and the size is 1 μm□
A recording medium characterized by having a smooth surface as described above. (7) The recording medium according to claim (6), further comprising a recording layer on the electrode substrate. (8) The recording medium according to claim (6), which has an electric memory effect. (9) The recording medium according to claim (7), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (10) The recording medium according to claim (7), wherein the recording layer has a thickness in the range of 5 to 300 Å. (11) Surface irregularities are 1 nm or less and the size is 1 μm
□It is characterized by comprising a step of forming an electrode layer containing an electrode material on a base material having a smooth surface as described above, a step of separating the electrode layer from the base material, and a step of forming a recording layer on the electrode layer. A method for manufacturing a recording medium. (12) The method for manufacturing a recording medium according to claim (11), wherein a crystal substrate whose main surface is cleaved is used as the base material. (13) The method for manufacturing a recording medium according to claim (11), wherein glass whose main surface is formed by melting is used as the base material. (14) The method for manufacturing a recording medium according to claim (11), wherein the electrode material is a noble metal or an alloy of noble metals. (15) The recording layer is formed using the Langmuir-Prodgett method (LB).
12. The method for producing a recording medium according to claim 11, wherein the recording medium is formed from an organic compound by a method (method). (16) Surface irregularities are 1 nm or less and the size is 1 μm
□An information processing device comprising a recording medium having a smooth surface as described above, a conductive probe disposed close to the recording medium, and a recording pulse voltage application circuit. (17) The information processing device according to claim (16), further comprising a recording layer on the electrode substrate. (18) The information processing device according to claim (16), wherein the recording medium has an electric memory effect. (19) The information processing device according to claim (17), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (20) The information processing device according to claim 17, wherein the recording layer has a thickness in the range of 5 to 300 Å. (21) Surface irregularities are 1 nm or less and the size is 1 μm
□An information processing device comprising a recording medium having a smooth surface as described above, a conductive probe disposed close to the recording medium, a recording pulse voltage application circuit, and a reproduction bias voltage application circuit. . (22) The information processing device according to claim (21), further comprising a recording layer on the electrode substrate. (23) The information processing device according to claim (21), wherein the recording medium has an electric memory effect. (24) The information processing device according to claim (22), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (25) The information processing device according to claim 22, wherein the recording layer has a thickness in the range of 5 to 300 Å. (26) Surface unevenness is 1 nm or less and the size is 1 μm
□ Information processing characterized by comprising a recording medium having a smooth surface as described above and on which information is recorded, a conductive probe disposed close to the recording medium, and a bias voltage application circuit for reproduction. Device. (27) The information processing device according to claim 26, further comprising a recording layer on the electrode substrate. (28) The information processing device according to claim (26), wherein the recording medium has an electric memory effect. (29) The information processing device according to claim (27), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (30) The information processing device according to claim (27), wherein the recording layer has a thickness in the range of 5 to 300 Å. (31) A recording layer is provided on the electrode substrate, and the surface unevenness is 1 nm.
A conductive probe is brought close to a recording medium having a smooth surface with a size of 1 μm or more, and a pulse voltage is applied between an electrode substrate and a conductive probe to record information. information processing method. (32) The information processing method according to claim (31), wherein the recording medium has an electric memory effect. (33) Claim (31) characterized in that the pulse voltage is a voltage exceeding a threshold value at which the conductivity of the recording medium changes.
The information processing method described in . (34) The information processing method according to claim (31), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (35) The information processing method according to claim (31), wherein the thickness of the recording layer is in the range of 5 to 300 Å. (36) A recording layer is provided on the electrode substrate, and the surface unevenness is 1 nm.
A conductive probe is brought close to a recording medium having a smooth surface with a size of 1 μm or more, and a pulse voltage is applied between the electrode substrate and the conductive probe to record information, and a bias voltage is applied. An information processing method characterized in that recorded information is reproduced by applying a voltage. (37) The information processing method according to claim (36), wherein the recording medium has an electric memory effect. (38) Claim (36) characterized in that the pulse voltage is a voltage exceeding a threshold value at which the conductivity of the recording medium changes.
The information processing method described in . (39) Claim (3) characterized in that the bias voltage is a voltage that does not exceed a threshold value at which the conductivity of the recording medium changes.
The information processing method described in 6). (40) The information processing method according to claim (36), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (41) The information processing method according to claim (36), wherein the recording layer has a thickness in the range of 5 to 300 Å. (42) A recording layer is provided on the electrode substrate, and the surface unevenness is 1 nm.
A conductive probe is brought close to a recording medium having a smooth surface with a size of 1 μm or more, and a first pulse voltage is applied between the electrode substrate and the conductive probe to record information, An information processing method characterized in that recorded information is reproduced by applying a bias voltage, and recorded information is erased by further applying a second pulse voltage. (43) The information processing method according to claim (42), wherein the recording medium has an electric memory effect. (44) Claim characterized in that the first pulse voltage is a voltage exceeding a threshold value at which the electrical conductivity of the recording medium changes.
42). (45) Claim (4) characterized in that the bias voltage is a voltage that does not exceed a threshold value at which the conductivity of the recording medium changes.
The information processing method described in 2). (46) Claim characterized in that the second pulse voltage is a voltage exceeding a threshold value at which the electrical conductivity of the recording medium changes.
42). (47) The information processing method according to claim (32), wherein the recording layer includes a monomolecular film or a monomolecular cumulative film of an organic compound. (48) The information processing method according to claim (42), wherein the thickness of the recording layer is in the range of 5 to 300 Å.