JPH05342646A - Recording method and information processing device - Google Patents

Abstract

PURPOSE:To increase transfer rate of recorded data and to rapidly process information of large volume by performing scanning for a recording medium with a probe electrode for the same region of the recording medium two times. CONSTITUTION:When recording is performed, a probe electrode 101 scans the same scanning region of a recording medium back and forth. In forth scanning, irregularity of recording medium surface is detected, and stored in a surface irregularity storage device 113. In this recording operation, the prove electrode scans in the direction of left side in the figure moving it up and down in accordance with irregularity information of recording medium surface stored in the surface irregularity storage device 113 in forth scanning. In back scanning, recording bits 124 are formed and recording is performed by applying voltage for recording and the like in accordance with information for recording and generating variation of conductivity in a recorded layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing device to which a scanning tunneling microscope is applied.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter referred to as STM) which allows a probe and a sample to be brought close to each other and to directly observe an electronic structure on the surface of a material and the vicinity of the surface by utilizing a physical phenomenon (tunnel phenomenon etc.) that occurs Abbreviated) was developed [G.Bi
nnig et al., Helvetica Physica Acta, 55,726 (198
2)], it has become possible to measure real space images with high resolution regardless of single crystal or amorphous. The STM also has the advantage that it can be observed at low power without damaging the medium with electric current, and it can be used not only in ultra-high vacuum, but also in air and in solution, and can be used for various materials. Therefore, it is expected to have a wide range of applications in academic and research fields.

The STM uses a tunnel current that flows when a distance of about 1 nm is approached with a voltage applied between a metal probe (probe electrode) and a conductive substance. The amount of this tunnel current changes very sensitively depending on the distance change between the two. Therefore, by scanning the probe so as to keep the tunnel current constant, it is possible to read various kinds of information regarding all electron clouds in the real space. The resolution in the in-plane direction at this time is about 0.1 nm.

Therefore, if the principle of STM is applied, it is possible to sufficiently perform high-density recording / reproduction on the atomic order (sub-nanometer). For example, JP-A-6
In the information processing apparatus disclosed in Japanese Patent Publication No. 1-80536, writing is performed by removing atomic particles adsorbed on the medium surface by an electron beam or the like, and this data is reproduced by STM.

As disclosed in US Pat. No. 4,575,822, a tunnel current flowing between the surface of a recording medium and a probe electrode is used to charge a dielectric layer formed on the surface of the medium. A method of injecting and recording, or recording by physically or magnetically destroying the surface of a medium using a laser beam, an electron beam, a particle beam, or the like has been proposed.

A method of performing recording / reproducing by STM using a recording medium having a memory effect with respect to switching characteristics of voltage and current as a recording layer, for example, a thin film layer of π-electron organic compound or chalcogen compound is disclosed. 63-16155
No. 2 and Japanese Patent Laid-Open No. 63-161553. According to these methods, if the recording bit size is 10 nm, it is possible to record and reproduce a large capacity of 10 ¹² bit / cm ² .

In the information processing apparatus as described above, in order to perform recording / reproduction on / from a recording medium, a so-called tracking positioning based on a predetermined standard, for example, a groove provided on the surface of the recording medium is used as a reference. An information processing device for performing is required.

[0008] In the case of an information processing apparatus for performing super-high density recording / reproducing using STM, generally, the probe is scanned while the above-mentioned tracking is performed and information bit strings are written one by one.

Further, when writing the information bit string, it is necessary to control the distance between the recording medium and the probe that serves as a pickup for recording during recording. JP-A-1-13
In Japanese Patent No. 3239, a recording method is proposed as a distance control method in which “the average value of the current before the current is strengthened for recording is held as a standard” at the time of recording.

[0010]

In the case of the ultra-high density information processing device as described above, due to the nature of how it is used,
There is a tendency that a large capacity and a high transfer rate are required.

However, in the conventional general recording / reproducing method,
Utilizing the tunnel current that flows similar to the STM principle,
A method of writing a recording bit by applying a recording voltage in accordance with recording information while scanning the probe electrode in the XY directions (horizontal direction to the recording medium surface) and simultaneously performing tracking by detecting unevenness of the recording medium surface is adopted. ..

Therefore, it is necessary to simultaneously perform feedback to detect the tunnel current flowing between the recording medium and the probe electrode so as to keep the current constant and keep the distance between the two constant. There is a problem in that the transfer rate for recording and reproduction is slowed down because the time required for the probe to perform reciprocal scanning while on is long.

For example, when recording is performed while repeating sample / hold (S / H) of the distance control signal as in the method disclosed in the above-mentioned Japanese Patent Laid-Open No. 1-133239, search is performed during the hold. It is necessary to wait until the distance between the probe and the recording medium becomes constant by the height control by the distance control signal between the writing of one bit and the writing of the next bit so that the needle does not collide with the recording medium. is there. In this way, the recording speed is limited by the response frequency of the height control.

Further, since the distance between the recording medium and the probe electrode is controlled by feeding back by the tunnel current, it is necessary to perform recording while setting the distance between them to be as close as the tunnel current flows. Depending on the recording medium, the optimum distance for recording may differ from the distance. In this case, it may affect the actual recording,
It was a problem.

The present invention has been made in view of the problems of the above-mentioned conventional technique, and realizes a recording method capable of increasing the transfer rate and an information processing apparatus using the recording method. With the goal.

[0016]

According to the recording method of the present invention, the recording information is the unevenness of the surface of the recording medium facing the probe electrode or the change of the electronic state. In the recording method which is performed by setting the strength of the tunnel current flowing between them during scanning, and the recording information is read by the information processing apparatus which is performed by detecting the tunnel current amount, Scanning of the recording medium is performed twice on the same area of the recording medium, and unevenness on the recording medium surface is detected by the first scanning, and unevenness on the recording medium surface detected by the first scanning is detected by the second scanning. Recording is performed by changing the distance between the probe electrode and the recording medium accordingly.

In this case, in the second scan, an offset may be added to the irregularities on the surface of the recording medium detected in the first scan to change the distance between the probe electrode and the recording medium.

Further, the information processing apparatus of the present invention uses asperities on the surface of the recording medium facing the probe electrodes or changes in the electronic state as recording information, and the recording information is written when the probe electrodes are scanned on the recording medium. In the information processing device, which is performed by setting the strength of the tunnel current flowing between them and reading the recorded information by detecting the tunnel current amount, the probe electrode is obtained by scanning the recording medium. A surface unevenness storage unit for storing unevenness information of the surface of the recording medium, an unevenness response drive mechanism for changing the distance between the probe electrode and the recording medium, a power supply for applying a recording voltage to the probe electrode, Scan the probe electrode with respect to the recording medium twice in the same area of the recording medium, and the first scanning causes The convex information is detected and stored in the surface concave-convex memory, and in the second scanning, the concave-convex response drive mechanism changes the distance between the probe electrode and the recording medium according to the concave-convex information stored in the surface concave-convex memory. And a control device for performing recording.

In this case, an offset adder for storing an offset amount added to the unevenness information stored in the surface unevenness memory may be provided.

Further, the surface unevenness memory may be constituted by a FILO type or FIFO type memory mechanism.

[0021]

According to the present invention, the same area of the recording medium is scanned twice when recording is performed, and in the second scanning when the actual recording is performed, the recording medium detected during the first scanning is performed. Recording is performed in a state in which the distance between the probe electrode and the recording medium changes according to the unevenness of the surface. As described above, since it is not necessary to feedback control the distance between the probe electrode and the recording medium at the time of recording, it is possible to increase the transfer rate of the recording data.

Further, by adding an offset to change the distance between the probe electrode and the recording medium, the distance between the probe electrode and the recording medium when detecting unevenness and the distance between the probe electrode and the recording medium when recording are performed. Each distance can be set to the optimum distance.

Further, when the surface unevenness memory for storing the surface unevenness information is constituted by a FILO type storage mechanism,
When the scanning is performed reciprocally, the distance between the probe electrode and the recording medium may be changed in the order of the data read from the storage mechanism, which simplifies the device configuration.

When the surface unevenness memory for storing the unevenness information of the surface is constituted by the FIFO type storage mechanism, the probe electrodes are moved in the same direction such as moving the probe electrodes circumferentially or spirally twice. When scanning is performed, the distance between the probe electrode and the recording medium may be changed in the order of data read from the storage mechanism.
The device configuration becomes simple.

[0025]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the figure, 101 is a probe electrode for recording / reproducing on / from a recording medium.
By applying a voltage to the recording medium mounted on the XY stage 102, recording bits are formed and read (recorded / reproduced).

The recording medium is composed of a substrate 121, a substrate electrode 122 and a recording layer 123 laminated on the substrate 121, and a recording bit 124 is formed in the recording layer 123 by applying a voltage from the probe electrode 101. It

Reference numeral 103 is a probe electrode 101 and a substrate electrode 1.
A probe current amplifier for amplifying the current flowing between 22 and
Reference numeral 105 denotes a Z-direction fine movement control mechanism using a piezoelectric element for adjusting the height of the probe electrode 101, and reference numeral 104 denotes a Z direction for reading the probe current and controlling the height adjustment of the probe electrode 101 by the Z-direction fine movement control mechanism 105. Drive circuit,
Reference numeral 106 is a power supply for applying a reproducing bias voltage and a recording / erasing pulse voltage between the probe electrode 101 and the substrate electrode 102. In the case of the apparatus according to the present invention, the feedback in the Z direction is turned off at the time of recording, so that the HOLD circuit in the Z direction drive circuit at the time of recording which is conventionally required is not necessary.

Reference numeral 108 is an XY-direction fine movement control mechanism for controlling the movement of the probe electrode 101 in XY directions, and 107 is an X-direction.
An XY scanning drive circuit for driving the Y-direction fine movement control mechanism 108. 109 and 110 are 10
-Coarse control of the distance between the probe electrode and the recording medium or the probe electrode 1 so that a probe current of about ^-9 A can be obtained.
01 is a coarse movement mechanism and a coarse movement drive circuit used to make a large relative displacement between the recording medium and the recording medium in the XY directions (outside the range of the fine movement control mechanism).

Reference numerals 113 and 114 denote a surface unevenness storage device and an unevenness response driving device, which are the most characteristic components of the present invention. The surface unevenness memory 113 stores the unevenness of the surface of the recording medium detected in the forward path of the first scanning of the probe electrode 101, and the unevenness response driving device 114 according to the unevenness information stores the unevenness of the second path in the backward path. Of the power source 106 while controlling the vertical movement of the probe electrode 101 of
Recording is performed by applying a recording voltage from the. Reference numeral 112 denotes a display element, which displays the formation state of the recording bit 124, the recorded information reproduced by this, and the like.

The operation of each of these devices is centrally controlled by the microcomputer 111.

Next, the recording method in this embodiment will be described with reference to FIG.

When recording, the probe electrode 101 is reciprocally scanned with respect to the same scanning area of the recording medium. In the forward path, as shown in FIG. 2A, the probe electrode 101 is scanned from the position at the left end to the right direction in the drawing by feedback in the Z direction by the tunnel current (vertical direction in the drawing) to scan the uneven surface of the recording medium. It is detected and stored in the surface unevenness memory 113.

When the probe electrode 101 reaches the right end and the storage of the surface irregularities for one row of the scanning area is completed, the recording operation is started. In this recording operation, after the feedback in the Z direction is turned off, as shown in FIG. 2B, the probe electrode 101 is moved up and down according to the unevenness information of the surface of the recording medium stored in the surface unevenness memory 113 on the outward path. Scan to the left in the drawing while moving. In this return path, a recording voltage or the like is applied according to the recording information to cause a change in conductivity or the like in the recording layer, whereby the recording bit 124 is formed and recording is performed.

However, in this case, since the scanning directions at the time of detecting the unevenness information of the surface of the recording medium are opposite to the scanning directions at the time of recording, the surface unevenness storage is performed so that the vertical movement of the probe electrode 101 matches the surface unevenness of the recording medium. The information from the device 113 has been converted. If the scanning direction during recording and the scanning direction during reproduction are opposite, the recording information is processed in advance.

As described above, in the present embodiment,
Since recording is performed without feedback in the Z direction on the return path, the scanning speed of the probe electrode 101 can be increased, so that the transfer rate during recording can be increased.

FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention.

In this embodiment, an offset adder 315 is added to add an offset to the surface unevenness information stored in the surface unevenness storage unit 113. The other structure is the same as that of the embodiment shown in FIG. ..

By providing this offset adder 315, the probe electrode 1 on the return path of the probe electrode 101
The distance between 01 and the recording medium can be maintained at a desired value, and recording can be executed in an optimum state.

The mechanical performance in the movement control using the piezoelectric element used in each of the above-mentioned examples is shown below.

Z direction fine movement control range: 0.1 nm to 1 μm Z direction coarse movement control range: 10 nm to 10 mm XY direction scanning range: 0.1 nm to 1 μm XY direction coarse movement control range: 10 nm to 10 mm Measurement and control tolerance: <0.1 nm (during fine movement control) Measurement and control tolerance: <1 nm (during coarse movement control) Hereinafter, a specific experimental example according to the above-described embodiment will be described.

[Experimental Example 1] An optically polished glass substrate (substrate 121) was washed with a neutral detergent and trichlene (trichloroethylene), and then Cr was used as an undercoat layer by vacuum deposition (resistance heating) to a thickness of 50Å. Then, Au is vapor-deposited by 1000Å by the same method to form the substrate electrode 122.
Formed.

Next, squarylium-bis-6-octylazulene (hereinafter abbreviated as SOAZ) was added at a concentration of 0.2 mg / m 2.
The chloroform solution dissolved in 1 was spread on the water phase at 20 ° C. to form a monomolecular film on the water surface. Wait for the solvent to evaporate,
The surface pressure of the monomolecular film was raised to 20 mN / m, and the electrode substrate was gently dipped at a speed of 5 mm / min so as to cross the water surface while keeping it constant. Next, this is pulled up to perform accumulation of two layers of Y-shaped monomolecular film to form a two-layer accumulation film (LB film) on the substrate electrode.
23. With such a configuration, the current −
It becomes a recording medium that causes a memory switching phenomenon (electric memory effect) in the voltage characteristics.

The electric memory effect is that a voltage exceeding a threshold value capable of transitioning to two different states is applied in a state where a thin film such as an organic monomolecular film or a cumulative film thereof is arranged between a pair of electrodes. This means reversibly transitioning (switching) to a low resistance state (ON state) and a high resistance state (OFF state), and retaining that state (memory).

A recording / reproducing experiment was conducted on the recording medium prepared by the above method using the information processing apparatus shown in FIG. However, as the probe electrode 101, a probe electrode made of platinum / rhodium prepared by an electropolishing method is used, and this probe electrode 101 has a distance (Z) that is set by a piezoelectric element so that a voltage can be applied to the recording layer 123. Controlled. Further, a fine movement control mechanism system is provided so that the probe electrode 101 can be controlled to move in the in-plane (X, Y) directions while having the above function.

Further, the probe electrode 101 can directly perform recording and reproduction. The recording medium is placed on the high-accuracy XY stage 102 and can be moved to any position. Therefore, recording / reproduction can be performed at an arbitrary position by the probe electrode 101 by this movement control mechanism.

Recording layer 1 obtained by accumulating the two SOAZ layers described above.
The recording medium having No. 23 was set in the information processing device. Next, a voltage of +1.5 V is applied between the probe electrode 101 and the substrate electrode 122 of the recording medium, and the distance (Z) between the probe electrode 101 and the substrate electrode 122 is monitored while monitoring the current flowing in the recording layer 123. It was adjusted. At this time, the probe current I _p for controlling the distance Z between the probe electrode 101 and the substrate electrode 122 was set to be 10 ⁻⁸ A ≧ I _p ≧ 10 ⁻¹⁰ A. Next, while keeping the distance Z between the probe electrode 101 and the substrate electrode 122 constant, the probe electrode 10
1 was scanned in the −X direction (see FIG. 2) and moved to the left end of the recording area.

Next, the probe electrode 101 was scanned to the right by feedback in the Z direction by a tunnel current. In this outward path, the unevenness of the surface of the recording medium is detected, and the detected unevenness information is stored in the surface unevenness storage unit 113.

Next, after the probe electrode 101 reaches the right end and the surface unevenness storage for one row of the scanning region is completed, the feedback in the Z direction is turned off, and the recording medium stored in the surface unevenness memory 113 on the forward path is stored. The probe electrode 101 was moved up and down in accordance with the surface irregularity information and was scanned leftward at a speed twice as fast as the forward path.

In this return pass, information was recorded at a pitch of 200Å. The recording of such information is performed by the probe electrode 1
With the 01 as the + side and the substrate electrode 122 as the-side, a triangular wave pulse as shown in FIG. 4 so that the electric memory material (SOAZ-LB film 2 layers) as the recording medium changes to the low resistance state (ON state). A voltage was applied. At this time, since the scanning direction at the time of detecting the unevenness information on the surface of the recording medium is opposite to the scanning direction at the time of recording, the position information from the surface unevenness storage device 113 is set so that the unevenness of the surface of the recording medium coincides with the vertical movement of the probe electrode 101. (X direction) has been converted. Further, in the apparatus used in this embodiment, the scanning directions at the time of recording and at the time of reproducing are opposite to each other, and therefore the recording information is processed in advance so that the recording bit string is in the opposite direction.

After that, the probe electrode 101 and the substrate electrode 1
The recording information previously written was read while applying a read bias voltage of +1.5 V between 22.
At this time, the voltage applied to the recording triangular wave pulse voltage is 0.
It turns out that a probe current of about 7 mA flows, it is changed to an ON state, that is, recorded, and that information to be recorded is accurately recorded over the entire recording / reproducing section,
It was shown that the recording is possible even if the recording speed is doubled.

That is, it has been proved that the recording / reproducing method of the present invention and the information processing apparatus using the same can increase the transfer rate during recording.

The thickness of one layer of the SOAZ was about 15Å as determined by the small angle X-ray diffraction method.

[Experimental Example 2] Just as in Experimental Example 1, a substrate electrode 122 was formed on a glass substrate 121, and then a recording layer 123 in which two polyimide LB films were accumulated was formed to obtain a recording medium. The method of forming the polyimide LB film is as follows.

A dimethylacetamide solution prepared by dissolving polyamic acid (molecular weight: about 200,000) at a concentration of 1 × 10 ^-3 % (g / g) was spread on the pure water aqueous phase at a water temperature of 20 ° C. A molecular film was formed. The surface pressure of this monolayer is 25m
The substrate was moved up to N / m, and while keeping this constant, the substrate was moved at 5 mm / min so as to traverse the water surface, immersed, and pulled up to accumulate a Y-type monomolecular film. next,
These films were made into polyimide by heating at 300 ° C. for 10 minutes. The thickness per polyimide layer was determined to be about 4Å by the ellipsometry method.

With respect to the recording medium prepared by the above method, the same recording / reproducing experiment as in Experimental example 1 was conducted except that the scanning speed of the probe electrode 101 in the returning path was tripled to increase the recording speed. However, it is confirmed that the data is recorded accurately over the entire recording / reproducing unit, and that the method and apparatus of the present invention can increase the transfer rate during recording.

Next, a second embodiment of the present invention will be described.

[Experimental Example 3] On a glass substrate (substrate 121) which has been optically polished, a Cr undercoat layer having a film thickness of 50 Å and an Au thin film layer having a film thickness of 1000 Å are formed by a vacuum evaporation method (resistance heating method). The electrode 122 was used. Next, by a plasma CVD method, hydrogen with a film thickness of 300 Å is deposited on the substrate electrode 122 by 30
%, The amorphous Si recording layer 103 was laminated. This recording layer was formed under the conditions of a pressure of 0.1 torr and a power of 50 W in the apparatus while keeping the substrate temperature at 200 ° C. and flowing a mixed gas of SiH ₄ and H ₂ into the 20 SCCM film forming apparatus.

The recording medium created in the above manner is shown in FIG.
Recording / reproducing experiments were conducted using the information processing apparatus shown in FIG. However, a probe electrode made of platinum / rhodium prepared by electropolishing is used as the probe electrode 101, and most of the driving mechanism and the recording mechanism of the probe electrode 101 are equal to or more than the device shown in FIG. It has a function.

Recording layer 123 made of hydrogen-containing amorphous Si
The recording medium having No. 1 was set in the information processing apparatus, and the distance between the probe electrode 101 and the recording medium was adjusted as in Experimental Example 1.

Next, the probe electrode 101 and the substrate electrode 12
While keeping the distance Z of 2 constant, the probe electrode 101 was scanned in the −X direction (see FIG. 2) and moved to the left end of the recording area.

Next, the probe electrode 101 was scanned in the right direction by feedback in the Z direction by a tunnel current. On this outward path, the unevenness of the surface of the recording medium is detected, and the unevenness information is stored in the surface unevenness storage device 113.

After the probe electrode 101 reaches the right end and the surface unevenness storage for one row of the scanning region is completed, the feedback in the Z direction is turned off, and in order to match the optimum recording condition of the recording medium, the surface is previously moved in the forward path. Uneven memory 113
By adding an offset from the offset adder 315 to the unevenness information of the surface of the recording medium stored in, the probe electrode 101 is moved up and down with the distance between the probe electrode 101 and the recording medium on the return path of the probe electrode 101 being 30 Å away from the forward path. However, scanning was performed leftward at a speed twice as fast as the outward path. At the same time, information was recorded at a pitch of 200Å on this return path.

The recording of such information is performed by the probe electrode 101.
Is set to the + side and the substrate electrode 122 is set to the − side, and a pulse voltage having a peak value of 5 V and a pulse width of 1 μsec is applied so that the hydrogen-containing amorphous Si changes. However, also in this case, as in Experimental Example 1, since the scanning directions at the time of detecting the unevenness information on the surface of the recording medium are opposite to the scanning directions at the time of recording, the surface unevenness storage device is arranged so that the surface unevenness and the vertical movement of the probe electrode coincide with each other. The position information (X direction) from is converted. Also,
In the apparatus used in this experimental example, the scanning direction at the time of recording and the scanning direction at the time of reproducing are opposite to each other, and therefore the recording information is processed in advance so that the recording bit string is in the opposite direction.

After that, the probe electrode 101 and the substrate electrode 1
The recording information previously written was read while applying the reading bias voltage +1 V between 22. At this time, the portion to which the recording pulse voltage is applied has a diameter of 10 nm.
It was found that the recording bits of a certain size were stably formed and that the recording information was accurately recorded. That is, in the conventional general recording method, there is a point that the recording bit size varies greatly and the accuracy in recording is lacking. However, according to the present invention, the transfer rate in recording can be increased, and the recording rate is appropriate. Accurate recording is possible under various recording conditions.

In Experimental Example 3 described above, the distance between the recording medium and the probe electrode is increased at the time of recording, but the distance is not limited to this, and it is important to meet the optimum recording condition of the recording medium. ..

The recording layer is not limited to the above-mentioned experimental examples as long as it has an electrical switching memory effect and can electrically change the state.
The forming method and the like are not limited to this.

Furthermore, in each embodiment, the probe electrode is described as one, but it is also possible to have two or more, such as one for recording / reproducing and one for tracking.

Next, a third embodiment of the present invention will be described.

FIG. 5 is a block diagram showing the configuration of the third embodiment of the present invention.

In this embodiment, like the embodiments shown in FIGS. 1 and 3, the positional relationship between the probe electrode and the recording medium is detected and stored during forward scanning, and the positional relationship stored during backward scanning is stored. Is used for recording. FIG. 5 shows in detail the portion that stores the detected positional relationship.

In the figure, 501 is a conductive probe electrode, 5
Reference numeral 02 denotes a cylindrical piezoelectric element that is a fine movement driving mechanism that drives the probe electrode 501 in the Z direction, and reference numeral 503 denotes a recording medium.
The cylindrical piezoelectric element 502 is configured so that an arbitrary recording bit string can be accessed by a coarse movement driving mechanism such as a linear motor (not shown).

Usually, the probe electrode 501 and the recording medium 50
A bias voltage is applied by the bias circuit 504 during the period of time 3, and the voltage is brought close to the extent that a tunnel current or a field emission current flows. This tunnel current or field emission current is input to the Z servo circuit 506 after being voltage-converted by the current-voltage conversion circuit 505. The Z servo circuit 506 outputs the distance control signal S3 so that the tunnel current or the field emission current becomes constant. The distance control signal S3 is applied to the electrode 50 which is the drive electrode of the cylindrical piezoelectric element 502.
8 is applied. The probe electrode 501 is made of platinum that is mechanically cut and sharpened.

A recording medium 503 is disclosed in Japanese Patent Laid-Open No. 63-1.
A material having an electric memory effect was used for the switching characteristics of voltage and current as disclosed in JP 61552 and JP 63-161553 A. These have basically the same configuration as that used in each of the experimental examples of the first and second embodiments. For example, as a substrate electrode, on a flat substrate such as glass or mica. A gold epitaxial growth surface is used. Then, as a recording medium, squarylium-bis-6-octylazulene (S
OAZ) is used to form a cumulative film of two monomolecular films on this substrate electrode by the Langmuir-Blodgett method.

Recording in this embodiment is performed as follows.

Usually, the probe electrode 501 and the recording medium 50
A bias voltage is applied by the bias circuit 504 during the period 3, and these are brought close to each other to the extent that a tunnel current flows. In this state, the probe electrode 501 is moved to a desired recording position on the recording medium 503, the bias voltage from the bias circuit 504 is modulated, and a voltage exceeding the threshold voltage at which the electric memory effect is generated is applied between the probe electrode 501 and the recording medium 503. Is applied to and recording is performed. Actually, a bias voltage of about 0.1 to 1 V is applied by the bias circuit 504 between the probe electrode 501 and the recording medium 503,
It is made close enough to a constant tunnel current (1 pA).

In this state, after moving the probe electrode 501 between desired recording positions on the recording medium 503, the bias voltage is modulated by the bias circuit 504, and a pulse voltage as shown in FIG. 4 is applied to the probe electrode 501 and the recording medium 503. When applied between the two, the magnitude of a current of about 0.7mA flows 1
A bit of 0 nmφ is formed, and after applying the pulse voltage,
Hold that state. Therefore, the bit in the low resistance state is associated with "1" to distinguish it from "0" in the high resistance state. Then, the encoder 515 adds “0”, “1” to the recorded data.
The data is encoded and the binary recording is performed.

At the time of binary recording, the probe electrode 501
Performs recording while scanning the recording medium 503 two-dimensionally with XY raster. At this time, the probe electrode 501 at the time of recording the bit of "1" in the forward scan of X (+ X direction).
After the horizontal and vertical relative positions of the recording medium 503 are temporarily stored, the Z-direction servo is turned off and the probe electrode 501 is relatively moved on the recording medium 503 by using the stored information at the time of the backward scanning (-X direction). After the end, the bias circuit 504 was controlled to record the bit corresponding to "1".

A specific recording method in this embodiment will be described with reference to FIG. 6 showing the operation of each section in FIG.

In this embodiment, during forward scanning (+ X direction), the control circuit 510 causes the switching circuit S2 to switch the SW circuit 50.
9 is switched to the A side. Thereby, the probe electrode 50
1 is applied to the electrode 508 to which a control voltage for determining the distance between the recording medium 503 and the recording medium 503 is applied, the distance control signal S3 according to the detection current of the probe electrode 501 by the Z servo circuit 506.
Is applied, and the tunnel current or field emission current flowing between the probe electrode 501 and the recording medium 503 is kept constant.

While controlling the height in the Z direction as described above, 1
Raster scanning (nth raster) is performed. At this time, the control circuit 510 determines that the probe electrode 501 has the recording medium 503.
Bit recording position corresponding to the above "1" (X0, Z in FIG. 6)
(Corresponding to 0), the X-direction scanning signal (X0) of the XY fine movement drive circuit 511 is generated by the control signals S1 and S4.
Is stored in a FILO (First In Last Out) memory 512 (corresponding to the surface unevenness storage unit 113 in FIGS. 1 and 3), and the value (Z0) of the distance control signal S3 at this time.
Is stored in the FILO memory 513.

By repeating this operation at the bit recording position during the forward scanning, the X direction scanning signal and the distance control signal S3 for the number of bits corresponding to "1" in one raster are stored in the FILO memories 512 and 513. To be done.

During the backward (-X direction) scanning in which the scanning direction of the probe electrode 501 is reversed, the SW circuit 509 is switched to the B side by the switching signal S2 output from the control circuit 510. As a result, the output of the Z drive circuit 514 placed under the control of the control circuit 510 is applied to the electrode 508. In this state, recording bits are formed on the recording medium 503. At this time, the output of the Z servo circuit 506 is the electrode 50.
8 is not applied, the height control of the probe electrode 501 as in the forward scan is not performed.

That is, the probe electrode 501 is moved to the recording position on the recording medium 503 in an open loop according to the data from the two FILO memories 512 and 513 during the backward scanning.

The drive control of the probe electrode 501 will be described in detail. The control circuit 510 controls the XY fine movement drive circuit 511 on the basis of the value stored in the FILO memory 512, and a signal for moving the probe electrode 501 in the horizontal direction ( The X-direction scanning signals X1 and X0 in FIG. 6 are output. At this time, the output of the Z drive circuit 514 is applied to the electrode 508 via the SW circuit 509. When the probe electrode 501 is moved in the horizontal direction, the control circuit 510 causes the Z drive circuit 514 to ensure that the probe electrode 501 has sufficient recording medium 503.
It outputs a voltage value Zinit that deviates from. After the horizontal movement is completed, the control circuit 510 outputs the value of the FILO memory 513 to the Z drive circuit 514 (voltage values Z1 and Z0 to the electrode 508) to control the probe electrode 501 in the height direction. In this state, the control circuit 510 changes the bias circuit 50.
4 is modulated to generate a pulse voltage, and bit recording corresponding to "1" is performed. After the completion of one bit recording, the Z drive circuit 514 outputs Zinit again to separate the probe electrode 501 from the recording medium 503, and to the bit recording position stored at the next address of the FILO memory 512, the probe electrode 5 is moved.
01 is moved and recording is performed.

As described above, the control circuit 510 changes all the bits stored in the value of the FILO memory during the backward scan (-X direction) and then changes the Y direction scan signal to move the probe electrode 501. Move to the next raster (n + 1th raster). At this time, switch the SW circuit 509 to A again.
Then, while the Z servo circuit 506 controls the distance between the probe electrode 501 and the recording medium 503, the forward scan (+ X direction) of the next raster is started.

According to this embodiment, the probe electrode 501 and the recording medium 5 for recording during the backward scanning (-X direction).
Since the relative movement speed between No. 03 and No. 03 does not depend on the response frequency of the Z servo circuit 506, it is possible to move at a speed close to the response frequency of the actuator, and it is possible to speed up recording. Further, since the FILO type memory mechanism is used, the distance between the probe electrode and the recording medium may be changed in the order of data read from the storage mechanism, and the device configuration can be simplified.

In the recording method according to the present invention, the probe electrode 501 is used as the recording medium 50 as shown in this embodiment.
The probe electrode 50 is not limited to a two-dimensional XY raster scan on the probe 3, but the probe electrode 50 is moved, for example, in a circular shape or a spiral shape, and the probe electrode
1 and the horizontal and vertical relative positions of the recording medium 503 are FIL.
After temporarily storing in an O or FIFO (First In First Out) type memory, the height servo may be turned off and the probe electrode may be relatively moved on the recording medium using the memory information to perform recording. Also in this case, the distance between the probe electrode and the recording medium may be changed in the order of data read from the storage mechanism, and the device configuration can be simplified.

FIG. 7 is a block diagram showing the configuration of the fourth embodiment of the present invention.

This embodiment has almost the same structure as that of the third embodiment shown in FIG. 5, but the bit recording is carried out by deforming the surface of the recording medium by the probe electrodes during recording.

Reference numeral 703 is a recording medium, and a probe electrode 701 facing the recording medium is provided close to the recording medium. The probe electrode 701 has a cylindrical piezoelectric element 702 and a probe electrode 701 which are the same Z fine movement mechanism as the cylindrical piezoelectric element 502 (see FIG. 5) in the third embodiment.
2 is attached to a Z coarse movement mechanism such as a stepping motor (not shown) for approaching the position 2.

Usually, the probe electrode 701 and the recording medium 70 are used.
A bias voltage from the bias circuit 704 is applied between the probe electrodes 3 and 3, and the probe electrodes 701 and the recording medium 703 are brought close to each other to the extent that a tunnel current or a field emission current flows. This tunnel current or field emission current is converted into a voltage by the current-voltage conversion circuit 705 and then input to the Z servo circuit 706. The Z servo circuit 706 outputs a distance control signal S73 for keeping the tunnel current or the field emission current constant. The distance control signal S73 is applied to the electrode 708 which is the drive electrode of the cylindrical piezoelectric element 702.

Recording in this embodiment is performed as follows.

As described above, the bias voltage by the bias circuit 704 is applied between the probe electrode 701 and the recording medium 703, and they are brought close enough to allow the tunnel current to flow. When performing recording, the control circuit 710 moves the probe electrode 701 to a desired recording position on the recording medium 703. After the movement is completed, the horizontal position of the probe electrode 701 is fixed, the SW circuit 709 is switched to the B side, and
The Z drive circuit 714 connects the probe electrode 701 to the recording medium 70.
A signal approaching 3 is generated and applied to electrode 708.
As a result, the probe electrode 701 pierces the recording medium 703 and deforms the surface of the recording medium 703 into a concave shape for recording.

In this embodiment, as the probe electrode 701, TiC, which is a hard material having conductivity, is electrolytically polished and used. Further, as the recording medium 703, Au epitaxially grown on mica was used. This recording medium 703
The probe electrode 701 is pierced on top and the size is 10 nm.
A minute bit having a φ and a depth of 0.5 nm was formed as a recording bit. The concave bit at this time is associated with "1" to distinguish it from "0" in the flat portion of the recording medium. The recorded data is encoded by the encoder 71.
At 5, the data of "0" and "1" is coded and binarized and recorded. At this time, the probe electrode 701 is attached to the recording medium 7.
Recording is performed while two-dimensional XY raster scanning is performed on 03.

At the time of this recording, the third data shown in FIG.
In the same way as in the embodiment described above, the horizontal and vertical relative positions of the probe electrode 701 and the recording medium 703 at the time of piercing are temporarily stored in the forward scan of X (+ X direction), and then the return scan (−X direction) is performed. The height servo was turned off and the relative movement of the probe electrode 701 on the recording medium 703 was performed, and then the probe electrode 701 was pierced to record the concave bit corresponding to “1”.

This specific recording method will be described with reference to FIG.

In this embodiment, during forward scanning (+ X direction), the SW circuit 709 is switched to the A side, and one raster scanning (nth raster) is performed while controlling the height in the Z direction. At this time, when the probe electrode 701 approaches the bit recording position corresponding to “1” on the recording medium 703, the control circuit 710 sends the X-direction scanning signal of the XY fine movement driving circuit 711 by the control signals S71 and S74.
In addition, the distance control signal S73 is stored in the FILO memory 713. By repeating this operation during the forward scan (+ X direction), the FILO memories 712 and 713 store the X-direction scan signal and the distance control signal S73 for the number of bits corresponding to “1” in one raster, respectively. To be done.

During the backward scanning (-X direction) in which the scanning direction of the probe electrode is reversed, the SW circuit 709 is switched to the B side,
The concave bits are recorded on the recording medium 703. At this time, the servo operation for controlling the height of the probe electrode 701 is not performed, and the probe electrode 701 is moved to the recording position on the recording medium 703 in an open loop according to the data stored in the two FILO memories 712 and 713. Be done.

The control circuit 711 controls the XY fine movement drive circuit 710 based on the value of the FILO memory 712 to move the probe electrode 701 in the horizontal direction. At this time, the Z drive electrode 7
08 is supplied with the output of the Z drive circuit 714 via the SW circuit 709.

The control circuit 710 controls the Z drive circuit 714 when the probe electrode 701 is moved in the horizontal direction.
Voltage value Zin such that 01 is sufficiently separated from the recording medium 703.
It is output, and the probe electrode 701 is moved in the horizontal direction in a separated state. After completion of the horizontal movement, the control circuit 7
Reference numeral 10 adds the recording voltage value (ΔZ) to the value of the FILO memory 713 for recording, and outputs it to the Z drive circuit 714.

The above ΔZ is calculated as follows.
For example, the cylindrical piezoelectric element 702 which is a Z control mechanism has a voltage-displacement characteristic of 0.5 nm / V, and the Z servo circuit 70
When the distance between the probe electrode and the sample is estimated to be 1 nm when the distance control is performed in No. 6, a voltage of 3 V is applied to the FILO memory 7 to make a concave bit having a depth of 0.5 nm.
It is given by adding to the value of 13. As a result, the recording medium 7
A concave bit recording corresponding to "1" is made on 02. When one bit recording is completed, the Z drive circuit 714 outputs Zinit again to set the probe electrode 701 to the recording medium 703.
Recording is performed by moving the probe electrode 701 to the bit recording position stored in the next address of the FILO memory 712.

In this way, during the backward scan (-X direction),
After recording is performed on all the bits stored in the value of the FILO memory, the Y-direction scanning signal is changed to move the probe electrode 701 to the next raster (n + 1th raster). At this time, the SW circuit 709 is switched to the A side again, and while the Z servo circuit 706 controls the distance between the probe electrode 701 and the recording medium 703, the next raster forward scan (+ X direction) is started.

In the present embodiment, the recording device in which the probe electrode is pierced into the recording medium by applying the STM has been described, but the concept of the present invention is not limited to this, and the probe may be provided on the surface of the recording medium such as AFM. It can also be applied to a recording device that records irregularities or changes in electronic state on the order of nm using electrodes.

[0106]

Since the present invention is constructed as described above, it has the following effects.

In the method according to the first aspect, since the recording is performed without performing the feedback control on the distance between the probe electrode and the recording medium, the transfer rate of the recording data can be increased and the large capacity can be achieved. There is an effect that the information of can be processed promptly.

In addition to the above effects, the method according to claim 2 has an effect that the distance between the probe electrode and the recording medium at the time of recording can be set to an optimum value.

According to the third and fourth aspects, there is an effect that an information processing apparatus having each of the above effects can be realized.

According to the fifth and sixth aspects, it is possible to simplify the device configurations of the information processing device for reciprocating the probe electrode and the information processing device for scanning the probe electrode in the same direction. There is.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a recording method of the present invention, in which (a) shows a forward scan and (b) shows a backward scan.

FIG. 3 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a triangular wave pulse voltage used for recording in the embodiment shown in FIG.

FIG. 5 is a block diagram showing a configuration of a third exemplary embodiment of the present invention.

6 is a diagram showing an operation of each unit in FIG.

FIG. 7 is a block diagram showing a configuration of a fourth exemplary embodiment of the present invention.

[Explanation of symbols]

 101, 501, 701 Probe electrode 102 XY stage 103 Probe current amplifier 104 Z direction drive circuit 106 Power supply 107 XY scanning circuit 108 XY direction fine movement control circuit 109 Coarse movement mechanism 110 Coarse movement drive circuit 111 Microcomputer 112 Display element 113 Surface unevenness memory Device 114 Concavo-convex response drive mechanism 121 Substrate 122 Substrate electrode 123 Recording layer 124 Recording bit 315 Offset adder 502,702 Cylindrical piezoelectric element 503,703 Recording medium 504,704 Bias circuit 505,705 Current voltage conversion circuit 506,706 Z servo Mechanism 509,709 SW circuit 510,710 Control circuit 511,711 XY fine movement drive circuit 512,513,712,713 FILO memory 514,714 Z drive circuit S1, S4, S7 , S74 control signal S2, S72 switching signals S3, S73 distance control signal

Front page continued (72) Inventor Hideyuki Kawagishi, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor, Takahiro Oguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kunihiro Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akihiko Yamano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Shunichi Shito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsunori Hatanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. The recording information is the unevenness of the surface of the recording medium facing the probe electrode or the change of the electronic state, and the recording information is written by a tunnel current flowing between the probe electrode and the recording medium when the recording medium is scanned. In the recording method performed by the information processing device, which is performed by setting the strength of the probe electrode and reading the recording information by detecting the tunnel current amount, the scanning of the probe electrode with respect to the recording medium is performed in the same area of the recording medium. 2 times, the unevenness on the surface of the recording medium is detected in the first scanning, and the distance between the probe electrode and the recording medium is detected in accordance with the unevenness on the recording medium surface detected in the first scanning in the second scanning. A recording method characterized by changing and recording. 2. The recording method according to claim 1, wherein in the second scanning, an offset is added to the irregularities on the surface of the recording medium detected in the first scanning to change the distance between the probe electrode and the recording medium. Characteristic recording method. 3. The unevenness of the surface of the recording medium facing the probe electrode or the change of the electronic state is used as the recording information, and the writing of the recording information is carried out by a tunnel current flowing between the probe electrode and the recording medium when the recording medium is scanned. In the information processing device, in which the recording information is read by detecting the tunnel current amount, the unevenness information of the surface of the recording medium obtained by scanning the probe electrode with respect to the recording medium is read. A surface unevenness storage device that stores the data, a unevenness response drive mechanism that changes the distance between the probe electrode and the recording medium, a power supply for applying a recording voltage to the probe electrode, and a scanning of the probe electrode with respect to the recording medium. The same area of the recording medium is performed twice, and the first scan detects the concave and convex information on the surface of the recording medium to detect the surface. A control device that causes the convex-convex storage device to store the recording data in the convex-convex response drive mechanism by changing the distance between the probe electrode and the recording medium according to the concave-convex information stored in the surface concave-convex storage device in the second scan. An information processing device having. 4. The information processing apparatus according to claim 3, further comprising an offset adder for storing an offset amount added to the unevenness information stored in the surface unevenness storage unit. .. 5. The information processing device according to claim 3, wherein the surface unevenness storage device is configured by a FILO type storage mechanism. 6. The information processing apparatus according to claim 3 or 4, wherein the surface unevenness storage unit is configured by a FIFO type storage mechanism.