JP2744341B2 - Access method, information processing method and information processing apparatus using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an access method and an information processing method and an information processing apparatus including recording / reproducing / erasing of information using the same.

More specifically, in a process including recording, reproduction, and erasure of information using the principle of a scanning tunneling microscope (STM), an access method that enables high-speed access of a probe electrode to a plurality of recording areas or reproduction areas. The present invention relates to an information processing method and an information processing device using the same.

[Conventional technology]

In recent years, the use of memory materials has become the core of the electronics industry such as computers and related equipment, video discs, digital audio discs,
The development of the material is also very active. The performance required for memory materials varies depending on the application, but in general, high density, large recording capacity, fast response time for recording and reproduction, low power consumption, high productivity, low price, etc. No.

Until now, semiconductor memories and magnetic memories using magnetic materials and semiconductors as the main material were mainly used.However, with the development of laser technology in recent years, inexpensive and high-density optical memories using organic thin films such as organic dyes and photopolymers have been developed. Recording media has appeared.

On the other hand, recently, a scanning tunneling microscope (hereinafter abbreviated as STM) capable of directly observing the electronic structure of surface atoms of a conductor has been developed [G. Binnig et al. Phys. Rev. Lett, 49, 57 (198
2)], it is possible to measure real space images with high resolution irrespective of single crystal or non-crystalline crystal, and has the advantage that it can be observed with low power without damaging the medium due to electric current. Above all, it operates and can be used for various materials, so that a wide range of applications is expected.

STM utilizes the fact that a tunnel current flows when the distance between the deep needle (probe electrode) of a metal and a conductive substance is reduced to about 1 nm. This current is very sensitive to changes in the distance between the two.By scanning the deep needle to keep the tunnel current constant, it is possible to draw the surface structure in real space, and at the same time, various types of surface electron clouds related to the total electron cloud Information can also be read. At this time, the resolution in the in-plane direction is about 0.1 nm.

Therefore, if the principle of STM is applied, it is possible to perform high-density recording / reproduction sufficiently in the atomic order (sub-nanometer). As a recording / reproducing method at this time, recording is performed by changing the surface state of an appropriate recording layer using a high-energy electromagnetic wave such as a particle beam (electron beam, ion beam) or X-ray or an energy beam such as visible or ultraviolet light. Recording / reproducing using a method of reproducing by STM, or a material having a memory effect on the switching characteristics of voltage and current as a recording layer, for example, a thin film layer of a π-electron organic compound or chalcogenide.
A method using STM has been proposed [Japanese Unexamined Patent Publication No.
No. 61552, JP-A-63-161553]. For example, according to this method, if the recording bit size is 10 nm,
Large capacity recording and reproduction of 10 ¹² bit / cm ² is possible.

In order to realize the above conventional example, the positioning of the probe electrode and the recording medium relative to each other requires accuracy of nanometers or less, and the device has high rigidity (a structure having a high resonance frequency) and high speed during recording / reproducing. It is required to have together.

At present, the driving element that satisfies these performances is a piezo-electrostrictive element.
Since the piezoelectric element is used alone for the drive mechanism of the relative positioning between the probe electrode and the recording medium, the recording area becomes as small as 10 μm and the recording capacity becomes 10 μm.
It becomes as small as ⁶ bit / cm ² . Therefore, in order to increase the capacity, it is necessary to combine the drive mechanism with the coarse movement.
When pulling in from the coarse movement region to the fine movement region by the piezo-electrostrictive element, it is necessary to provide a fine movement position reference pattern having a structure larger than the coarse movement accuracy.

[Problems to be solved by the invention]

However, in this method, since the fine movement position reference pattern is two-dimensionally scanned and the fine movement area is positioned based on the two-dimensional image, the two-dimensional scanning of the probe electrode is performed when accessing the recording area of the probe electrode. There is a disadvantage that it takes a long time to process the dimensional image data.

Therefore, an object of the present invention is to solve such a drawback, and to provide an access method capable of performing access of a probe electrode to a plurality of recording areas or reproduction areas with high accuracy and high speed and performing large-capacity recording, and an access method capable of performing large-capacity recording. An object of the present invention is to provide an information processing method and an information processing apparatus that are used.

[Means for solving the problem]

 The above object is achieved by the present invention described below.

That is, the present invention relates to a method of accessing a probe electrode to a reference point of a format pattern for a medium having a format pattern having a reference point, wherein the probe electrode is moved so that the probe electrode crosses the format pattern. Scanning, detecting a change in current caused by such scanning, detecting a reference point of the format pattern based on the detected change in current, and moving the probe electrode to the detected reference point. This is a characteristic access method.

The present invention also provides a method of scanning a probe electrode across a medium having a format pattern having a reference point so as to cross the probe electrode on the format pattern, and detecting a change in current caused by the scanning. Detecting a reference point of the format pattern based on the change in the detected current, and moving the probe electrode to the detected reference point; scanning the probe electrode along the format pattern to obtain information along the format pattern. An information processing method characterized by including a step of recording information.

Further, according to the present invention, the probe electrode scans the medium on which information is recorded along the format pattern having the reference point so that the probe electrode crosses the format pattern, and a change in current caused by the scanning is detected. Detecting, detecting a reference point of the format pattern based on a change in the detected current, moving the probe electrode to the detected reference point, scanning the probe electrode along the format pattern, and recording. An information processing method characterized by including a step of detecting and reading current information that has been read.

The present invention scans a probe electrode on a medium on which information is recorded along a format pattern having a reference point so that the probe electrode crosses the format pattern, and detects a change in current caused by the scanning. Detecting the reference point of the format pattern based on the detected change in the current, moving the probe electrode to the detected reference point, scanning the probe electrode along the format pattern, and recording An information processing method characterized by including a step of erasing existing information.

The present invention is characterized by comprising a recording medium having a format pattern having a reference point, a probe electrode arranged close to the recording medium, and a circular scanning drive mechanism for making the probe electrode circularly scan. It is an information processing device.

(Preferred embodiment)

According to a preferred aspect of the present invention, when applying a voltage to a recording medium while circularly scanning a recording / reproducing probe electrode to perform recording / reproducing, a circumferential format pattern is preliminarily formed at a central portion of a recording area. Is recorded, and the probe electrode is scanned in the circumferential direction, and the scanning pattern and the format
By detecting the positional relationship of the pattern and accessing the probe area to the recording area,
A large-capacity information processing device capable of high-speed access is realized.

〔Example〕

FIG. 1 shows a preferred embodiment of the present invention. In this figure, a substrate growth surface of gold or a cleavage surface of graphite is used as a substrate electrode 101 on a flat substrate such as glass or mica. Squarylium- as the recording layer 102
Using bis-6-octylazulene (hereinafter abbreviated as SOAZ), a two-layer monomolecular film is formed on the surface of the substrate electrode 101 by a Langmuir project method. Next, the probe electrode 104 is moved to the recording layer 10 by the vertical driving mechanism 103.
2. Close the desired position to a distance of about sub-nanometer. Here, as the probe electrode 104, a tungsten wire or the like which is electrolytically polished, or a platinum wire or the like which is mechanically cut, which has a sharp tip (curvature radius <1 μm) and has conductivity is used. The vertical drive mechanism 103 has PZT
Using a device or the like, a voltage (bias voltage) of about 0.1 to 1 V is applied between the substrate electrode 101 and the probe electrode 104 by a bias power supply 105, and a probe current flowing between the two is detected by a probe electrode detector 106, Probe current value Ip is 1
The distance between the probe electrode 104 and the substrate electrode 101 is adjusted by the servo circuit 107 so as to be substantially constant between 0 ^-10 AIp10 ^-8 A.

Recording / erasing of information is performed as follows. The signal from the recording / erasing signal generator 108 is applied to the substrate electrode 101 and the probe electrode 10.
4 and the recording layer 10 close to the tip of the probe electrode 104.
2. Recording / erasing of information at a desired position. Similarly, in reproducing information, a bias voltage for reading is applied between the substrate electrode 101 and the probe electrode 104 by the bias power supply 105, and the information is reproduced at a desired position of the recording layer 102 close to the tip of the probe electrode 104. Specifically, a current value was measured by applying a reading voltage of 1.5 V, which is a voltage not exceeding a threshold voltage that causes an electric memory effect, between the probe electrode 104 and the substrate electrode 101, and the current value was μA or less. so
OFF state was shown. Next, the threshold voltage V _th-ON that causes the ON state
After applying the triangular pulse voltage having the waveform shown in FIG. 5 as the above voltage, a voltage of 1.5 V was applied again between the electrodes for reproduction, and a current of about 0.7 mA flowed. The state was shown. That is, the ON state was recorded. Next, after applying a triangular wave pulse voltage having a peak voltage of 5 V which is a voltage equal to or higher than the threshold voltage V _{th-OFF which} changes from an ON state to an OFF state and a pulse width of 1 μs, 1.5 V is again applied for reproduction. It was confirmed that the current value returned to the OFF state at μA or less.

Note that the electric memory effect referred to in the present invention indicates at least two or more different resistance states in response to voltage application,
The transition between the states can be freely made by applying a voltage or current exceeding a threshold value that changes the conductivity of the recording layer, and the obtained resistance states can be changed as long as a voltage or current that does not exceed the threshold value is applied. In that state can be maintained.

Further, specific examples of the material constituting the recording layer include, for example, (1) oxide glass, borate glass, or a periodic table.
Amorphous semiconductors such as chalcogenide glasses containing Se, Te, and As combined with Group III, IV, V, and VI elements are included. They are intrinsic semiconductors having an optical band gap Eg of 0.6 to 1.4 eV or an electric activation energy ΔE of about 0.7 to 1.6 eV. Specific examples of chalcogenide glasses include As-Se-Te, Ge-As-Se, and Si-Ge-As-Te.
System, for example, Si ₁₆ Ge ₁₄ As ₅ Te ₆₅ (subscript is atomic%), or Ge-Te-X system, Si-Te-X system (X = a small amount of V, group IV element) such as Ge ₁₅ Te ₈₁ Sb ₂ S _2, and the like. Furthermore, Ge-Sb
-Se-based chalcogenide glass can be used.

(2) Further, tetracyanoquinodimethane (TCNQ), TCNQ
Derivatives, for example, electron-accepting compounds such as tetrafluorotetracyanoquinodimethane (TCNQF ₄ ), tetracyanoethylene (TCNE) and tetracyanonaphthoquinodimethane (TNAP), and metals having relatively low reduction potential such as copper and silver. And an organic semiconductor layer having a salt deposited on an electrode.

As a method of forming such an organic semiconductor layer, a method of vacuum-depositing the electron-accepting compound on a copper or silver electrode is used.

(3) Further, a recording medium in which a molecule having both a group having a π-electron level and a group having only a σ-electron level is laminated on an electrode can be given.

Examples of the structure of the dye having a π-electron system suitable for the present invention include, for example, phthalocyanine, a dye having a porphyrin skeleton such as tetraphenylporphyrin, an azulene-based dye having a squarylium group and a croconite methine group as a bonding chain, and quinoline. Cyanine-like dyes in which two nitrogen-containing heterocycles such as benzothiazole and benzoxazole are bonded by a squarylium group and a croconite methine group, or cyanine dyes, condensed polycyclic aromatics such as anthracene and pyrene, and aromatic and A chain compound in which a heterocyclic compound is polymerized and a polymer of a diacetylene group, furthermore, a derivative of tetracyanoquinodimethane or tetrathiafulvalene and an analog thereof and a charge transfer complex thereof, or even a ferrocene or trisbipyridine ruthenium complex. Metal complex compound And the like.

In addition to the above low-molecular materials, various high-molecular materials can be used.

Examples thereof include addition polymers such as polyacrylic acid derivatives, condensation polymers such as polyimide or polyphenine and polythiophene, ring-opening polymers such as nylon, and biopolymer materials such as polypeptides and bacteriorhodopsin.

Next, position control of the probe electrode in recording / reproducing of information will be described with reference to FIGS. As the circular scanning drive mechanism 109 of the probe electrode 104, for example, a cylindrical piezo element having a divided electrode pattern as shown in FIG.
4 Each voltage as follows Here, ω: angular velocity V (t): voltage amplitude A, B: constant Vos, Vos ′: probe offset fine adjustment DC offset voltage (described later) is applied to operate the probe electrode 104 spirally. While applying the triangular pulse voltage between the probe electrode 104 and the substrate electrode 101 in the manner described above,
The ON state was written by various pitches between 01 μm and 0.1 μm, and continuous data was spirally recorded in a certain recording area on the recording layer 102. Here, the amplitude of the voltage applied to each of the divided electrodes 201 to 204 is V (t) = C · Int (ωt / 2π) + D where C and D are constants, and Int (x) is an integer part of x. And concentric recording can be performed. Next, reproduction was performed by applying a voltage of 1.5 V between the probe electrode 104 and the substrate electrode 101 while operating the probe electrode 104 in a helical manner exactly as in recording, and a resolution of 0.01 μm or less was obtained. And a continuous data signal could be read at a constant speed.

Now, a method of accessing the probe electrode 104 to a plurality of recording areas will be described. As shown in FIG. 3, the initial medium (FIG. 3 (a)) is pre-formatted. That is, each recording area a-1, a-2,.
The recording bit of the format pattern 301 having a reference point (having the center in this example) is recorded at substantially the center of 1, b-2,... As shown in FIG. 3 (b). At this time, the positioning of the probe electrode 104 at the center of each recording area is performed by the coarse movement driving circuit 112 and the coarse movement mechanism 113 in accordance with the set value of the micro computer 111, and the probe for recording the circular format pattern 301 is formed. The driving of the electrode 104 is performed by the circular scanning driving circuit 110 and the circular scanning driving mechanism 109 according to the set value of the microcomputer 111. Here, the address information data of each area is
Record it in the pattern. Recording medium after format
In the method of accessing the probe electrode 104 to a desired recording area with respect to 102, as shown in FIG. 4, first, the tip of the probe electrode is positioned inside the format pattern of the recording area (FIG. )).

This positioning is performed by the coarse movement function 113, but since the tip of the probe electrode is guaranteed to be always inside the format pattern, the radius of the format pattern may be larger than the positioning accuracy of the coarse movement mechanism. is necessary. Next, as shown in FIG. 4 (b), a circular scan of the tip of the probe electrode is performed (the radius of the circular scan is slightly smaller than the radius of the format pattern). At this time, if the center of the recording area does not coincide with the center of the circular scanning, the probe electrode detects the format pattern bit during the circular scanning as shown in FIG. from Δθ position theta ₀ of the _midpoint), positional deviation direction and the deviation amount of the center (in the figure, can be detected are offset circle scanning center) in the direction of 2 o'clock with respect to the recording region center. Here, the driving voltage V _{+ X} applied to the circular scanning driving mechanism 109
DC offset voltages Vos and Vos' as described above are added to .about.V- _Y so that the center of the circular scanning coincides with the center of the recording area (FIG. 4 (c)). At this time, the values of the probe electrodes are as shown in FIG. 4 (c ').

As described above, the probe electrode to the desired recording area
After the access at 104, as shown in FIG. 3 (c), recording is performed by circular scanning of the probe electrode around the format pattern (here, in the recording area b-2). After the recording to the desired recording area is completed, when recording to another recording area, the center of the desired scanning area is made to coincide with the center of the circular scanning of the probe electrode by the above-described access method.
Recording is performed in the same manner.

Similarly, with respect to the access method at the time of reproduction, the tip of the probe electrode is positioned inside the format pattern of the desired recording area, and a circular scan is performed to make the center of the recording area coincide with the center of the circular scan. Thereafter, as shown in FIG. 3D, the data recorded around the format pattern (here, in the recording area a-2) is reproduced by circular scanning of the probe electrode.

By the way, when information is actually recorded / reproduced using the access method described above, typically, the diameter of the recording bit
10 nm, diameter of the format pattern ~ 100 nm, diameter of one recording area ~ 10 μm, size of the entire recording area ~ 10 mm, positioning accuracy of the circular scanning drive mechanism ~ 0.1 nm, positioning accuracy of the coarse movement mechanism ~ 10 nm, high High density capacity (~ 10 ¹² bit / cm ² ),
High-speed access (10 ms or less) recording / reproduction is now possible.

As described above, as a preferred embodiment of the present invention, the example in which the format pattern is made to be circumferential and the tip of the probe electrode is circularly scanned to access a desired recording area or reproduction area has been described. The scanning method of the probe electrode tip is not particularly limited as long as it is included in the concept of the present invention.

〔The invention's effect〕

As described above, the circumferential format pattern is recorded at the center of the recording area, the probe electrode is scanned in the circumferential direction, the positional relationship between the scanning pattern and the format pattern is detected, and the recording area is recorded. Large-capacity information processing with a simple configuration and high-speed access with a positioning accuracy of 1 nanometer or less without performing complicated processing such as two-dimensional data processing by accessing the probe electrodes The device can be realized. Also, it is not necessary to provide a special pattern (different from the recording bit and the arrangement of the recording bits) in the format pattern as the position reference pattern, and the same pattern as the arrangement of the recording bits is used as it is as the position reference pattern. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram of an information processing apparatus embodying the present invention, FIG. 2 is a diagram showing a circular scanning drive mechanism of a probe electrode, FIG. 3 is a diagram showing an arrangement of recording areas in the present invention, FIG. FIG. 5 is an explanatory diagram of a method for accessing a recording area in the present invention, and FIG. 5 is a diagram showing a recording signal waveform. 101 substrate electrode 102 recording medium 103 vertical driving mechanism 104 probe electrode 105 bias power supply 106 probe current detector 107 servo circuit 108 recording / erasing signal generator 109 … Circular scanning drive mechanism 110… Circular scanning drive circuit 111… Microcomputer 112… Coarse movement drive circuit 113… Coarse movement mechanism 201-204… Electrode 301… Form pattern

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takahiro Oguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kunihiro Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. (56) References JP-A-64-53364 (JP, A)

Claims (20)

(57) [Claims] 1. A method for accessing a reference point of a format pattern with a probe electrode for a medium having a format pattern having a reference point, wherein the probe electrode scans the probe electrode so as to cross over the format pattern, Detecting a change in current caused by the scanning, detecting a reference point of the format pattern based on the detected change in current, and moving a probe electrode to the detected reference point. Method. 2. The access method according to claim 1, wherein the reference point is a center of the format pattern. 3. The access method according to claim 1, wherein the format pattern is a circular pattern. 4. The access method according to claim 1, wherein a change in current is detected by circularly scanning the probe electrode. 5. A step of scanning a probe electrode with respect to a medium having a format pattern having a reference point so that the probe electrode crosses the format pattern, and detecting a change in current caused by such scanning. Detecting the reference point of the format pattern based on the change of the, and moving the probe electrode to the detected reference point,
An information processing method comprising a step of recording information on the probe electrode along a format pattern. 6. The information processing method according to claim 5, wherein the recording of information is performed by applying a voltage exceeding a threshold voltage causing an electric memory effect between the probe electrode and the medium. 7. A probe in which information is recorded along a format pattern having a reference point is scanned by the probe electrode so as to cross the format pattern, and a change in current caused by the scanning is detected. A step of detecting a reference point of the format pattern based on a change in the detected current, a step of moving the probe electrode to the detected reference point, and information recorded by scanning the probe electrode along the format pattern. An information processing method including a step of detecting and reading a current. 8. The information processing method according to claim 7, wherein the reading of information is performed by applying a voltage between the probe electrode and the medium that does not exceed a threshold voltage causing an electric memory effect. 9. The information processing method according to claim 7, wherein the applied voltage is a bias voltage. 10. A probe on a medium on which information is recorded along a format pattern having a reference point so that the probe electrode crosses the format pattern, and a change in current caused by the scanning is detected. A step of detecting a reference point of the format pattern based on a change in the detected current, a step of moving the probe electrode to the detected reference point, and information recorded by scanning the probe electrode along the format pattern. An information processing method, comprising the step of erasing information. 11. The information processing method according to claim 10, wherein the information is erased by applying a voltage exceeding a threshold voltage causing an electric memory effect between the probe electrode and the medium. 12. The information processing method according to claim 5, wherein the reference point is the center of the format pattern. 13. The information processing method according to claim 5, wherein the format pattern is a circular pattern. 14. The information processing method according to claim 5, wherein a change in current is detected by circularly scanning the probe electrode. 15. The information processing method according to claim 5, wherein the medium has an electric memory effect. 16. A recording medium having a format pattern having a reference point, a probe electrode arranged close to the recording medium, and a circular scanning drive mechanism for circularly scanning the probe electrode. Information processing device. 17. The information processing apparatus according to claim 16, wherein the reference point is a center of the format pattern. 18. The information processing apparatus according to claim 16, wherein the format pattern is a circular pattern. 19. The information processing apparatus according to claim 16, wherein the recording medium has an electric memory effect. 20. A recording / erasing signal generating means.
16. The information processing device according to item 16.