JP2942013B2 - Recording and / or playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording information and / or reproducing information.

[0002]

2. Description of the Related Art An information storage element or an information storage device, a so-called memory, is not only the core of a computer and its related equipment, but also a video device and an audio device as seen in a video disk, a digital audio disk and the like. It occupies an important position among them. The performance required of this memory depends on the application, but in general,

[0003] High density and large recording capacity. Fast response speed for recording and playback. Low power consumption. High productivity and low price. At present, the development of a memory system and a memory medium for realizing such performance is being actively promoted.

Conventionally, the center of a memory has been a magnetic memory and a semiconductor memory using a magnetic material and a semiconductor as a material.
In recent years, with the progress of laser technology, inexpensive and high-density optical memories using organic thin films such as organic dyes and photopolymers have appeared.

At present, technology development for miniaturization of a unit memory bit is proceeding in order to further increase the density and the capacity of these memories, but based on a completely different principle from those of the conventional memories. There is also a proposal for memory. For example, a concept of a molecular electronic device in which each organic molecule has a function of a logic element or a memory element is one of them. Although it can be seen that molecular electronic devices have advanced the miniaturization of unit memory bits to the limit, how to access individual molecules has been a problem so far.

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. Binning et a
l. , Helvetica Physica Act
a, 55 , 726 (1982)] Real space images can be observed with high resolution regardless of whether they are single crystals or amorphous. S
TM has the advantage that it can be observed at low power without damaging the sample due to electric current. Furthermore, it can be operated in air and can be used for various materials, so it is expected to be applied to a wide area. Have been. Recently, it has been reported that it is possible to observe even a molecular image of an organic molecule adsorbed on a conductor surface.

On the other hand, an atomic force microscope (hereinafter abbreviated as AFM) to which the STM technique is applied has been developed, and [G. Bi
nnig et al. , Pluys Rev. Let
t. , 56 , 930 (1985)] As in the case of the STM, it is possible to obtain surface unevenness information. AFM
Can be measured on an atomic order even for insulating samples, so future development is desired.

The STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe (probe electrode) and a conductive substance so that the distance between them is reduced to about 1 mm. This current is extremely sensitive to changes in the distance between them,
By scanning the probe over the surface of the conductive material while controlling the distance between them so as to keep this tunnel current constant, it is possible to draw the surface configuration of the real space of this conductive material and simultaneously Various information on all electron clouds can be read. At this time, the resolution in the in-plane direction is about 1 °. Therefore, if the principle of STM is applied,
High-density recording and reproduction on the order of atoms (several オ ー ダ ー) can be performed sufficiently. In this case, the recording / reproducing method
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 light or ultraviolet light, and reproducing by STM. Method and medium having a recording property as a recording layer, which has a switching property of transitioning to a state having different conductivity by applying a voltage, and has a memory property in which each state having a different conductivity is retained even when no voltage is applied. For example, recording and reproduction are both performed using a thin film layer of an organic compound or a chalcogen compound rich in π-electron conjugated system.
A method using an M apparatus has been proposed.

[0009]

As a reproducing method in an apparatus for performing recording or reproducing as described above, a method of reproducing a probe electrode on a medium surface while maintaining a constant current flowing between the probe electrode and the surface of the recording medium is described. When scanning is used, the probe electrode moves away from the medium surface in an area with high conductivity, and the amount of movement of the probe electrode is detected to reproduce the recording bit, or the distance between the probe electrode and the recording medium is The probe electrode is scanned over the surface of the medium while keeping the constant, and the amount of current flowing between the probe electrode and the surface of the recording medium is increased over the region of high conductivity. There is something to play.

However, when the former reproducing method is adopted, the probe electrode follows even the slight irregularities of the recording medium, so that the discrimination between the irregularities on the medium surface and the recording bits is made only from the movement amount of the probe electrode. It was difficult. Also, the controllable scanning frequency is limited by the upper limit of the band of the feedback control circuit for keeping the current constant,
High speed scanning was difficult. Also, in the case of the latter reproducing method, high-speed scanning is possible, but the amount of current also changes due to irregularities on the medium surface, and it is difficult to distinguish the same as in the former method. Furthermore, the probe electrode and the medium surface are separated by a certain distance, and this acts as an insulating barrier.This barrier is common to the recording bit write portion and the other region, and is effectively connected in series as a tunnel resistance. Will be inserted. As a result, if the distance between the probe electrode and the medium surface changes, the ratio of the amount of current detected between the written part and the non-written part will differ greatly, which may cause a problem when reading bits accurately. was there.

Therefore, it is necessary that the reproduced signal is obtained by separating components due to the unevenness of the recording medium, and the tunnel resistance caused by the insulating barrier between the probe electrode and the surface of the recording medium is kept as small and constant as possible. Therefore, it is necessary to increase the reproduction signal ratio depending on the presence or absence of recording bits as much as possible. Also, during recording, the applied voltage change due to recording is
It is preferable that the distance between the probe electrode and the medium be hardly affected.

Further, when the distance between the recording medium and the probe electrode is large, it is preferable that the separation capability as an STM decreases, that is, from the viewpoint of recording density, the recording medium and the probe electrode are as close as possible.

In order to remove the component due to the unevenness of the medium surface from the reproduction signal and to make the interval control at the time of recording independent of the applied voltage, the distance between the medium surface and the probe should be an amount other than the current flowing between them. Japanese Patent Application Laid-Open No. 1-245445 discloses the use of an atomic force microscope (AFM) in which the distance is controlled by an atomic force acting between the two.

In the AFM, the probe electrode is supported by an elastic body, and the force acting between the tip of the probe electrode and the surface of the recording medium is balanced with the spring force due to the deformation of the elastic body, and feedback is performed so as to keep this deformation constant. Control is performed.

The present invention is an application of the above-mentioned conventional example. The object of the present invention is to use an atomic force in a simpler form to keep information on a probe medium as constant as possible and to record and / or record information. An object of the present invention is to provide a device capable of performing reproduction.

[0016]

In order to achieve the above object, the present invention provides an apparatus for recording and / or reproducing information on an information recording medium via a probe, wherein an elastic member for supporting the probe is connected to the probe. Controlling the probe / information recording medium interval by arranging the probe / information recording medium such that a force deforming in the direction of correcting the interval variation of the information recording medium acts between the probe / information recording medium; In the control state, a voltage is applied between the probe and the information recording medium to record information, and / or the probe and the information recording medium are recorded.
Reproduction is performed by detecting a current between information recording media. In an apparatus for recording and / or reproducing information via a probe facing an information recording medium, the distance between the medium and the probe is variable by deforming an elastic member supporting the probe. And a close arrangement where a force acting between
The acting force itself makes the elastic member flexible, and in this state, a voltage is applied between the probe and the medium to record information and / or a current is detected between the probe and the medium to reproduce the information. I do it.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiments described below, a configuration is used in which a probe electrode is supported by an elastic body and a repulsive force acting between the probe electrode and the recording medium is balanced with a spring force due to deformation of the elastic body. As the elastic body, for example, a probe electrode is provided at the center of the double-supported beam or at the free end of the cantilever. Au, Ni, SuS, Be are used as the material of the beam.
It is preferable to use a foil of CuP or the like, and a finer beam can be formed by using a SiO ₂ thin film which is often performed by micromechanics.

Since the force acting between the probe electrode and the recording medium is very small, it is preferable that the masses of the probe electrode and the elastic support be as small as possible, and the elastic support is soft to increase the change, and It is desirable to be strong against external vibrations.

The probe electrode is scanned over the surface of the recording medium with the distance between the probe electrode and the recording medium approaching until a repulsive force acts between them, and a desired voltage is applied between them by a voltage application circuit. To perform recording, reproduction, and erasure.

It is preferable that the tip of the probe electrode is as sharp as possible in order to increase the resolution of recording, reproduction and erasing. In the present invention, a probe is used in which Si is implanted on a SiO ₂ substrate with a focused ion beam, Si is selectively crystallized on Si, and Au is vapor-deposited and conductive treatment is performed. The shape and processing method are not limited to these.

The recording medium used in the present invention may be any medium as long as its conductive state changes when a voltage is applied and the conductive state is maintained without applying a voltage. As a medium, JP-A-6
JP-A-3-161552 and JP-A-63-161553
And a medium composed of an organic material having a group having a π-electron level, and more preferably a monomolecular cumulative film of the organic material formed by a Langmuir project method (LB method). Is mentioned.

The monomolecular accumulation film 43 as described above is
The MIM structure element (FIG. 7) sandwiched between 1, 42 shows current-voltage characteristics as shown in FIG. 8 and FIG.
No. 956). The two states (the ON state and the OFF state) transition with each other by applying a voltage equal to or higher than the threshold, and each state is maintained at or below the threshold voltage. These characteristics are exhibited when the film thickness is several to several thousand degrees, but as a recording medium in the examples described later, JP-A-63-161552 and JP-A-63-161552
As disclosed in Japanese Patent No. 161553, several Å to 500
A film having a thickness in the range of Å is good, and most preferably 10Å
Those having a film thickness of 200 ° are good.

The electrode material used in the embodiments described later may be any material having a high conductivity.
Numerous materials including metals such as u, Pt, Ag, Pd, Al, In, Sn, Pb, W, and alloys thereof, and graphite, silicide, and conductive oxides such as ITO. Therefore, these applications to the present invention can be considered. As a method for forming an electrode using such a material, a conventionally known thin film technique is sufficient. However, the electrode material directly formed on the substrate is a conductive material that does not form an insulating oxide film when the surface is formed of an LB film, such as a noble metal or IT.
It is preferable to use an oxide conductor such as O.

The metal electrode of the recording medium is preferably used when the insulating property of the recording layer is high.
The metal electrode need not be used as long as it has the following semiconductor properties.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a recording / reproducing apparatus according to the present invention. 1 is a recording medium, 2 is a probe electrode provided facing the recording medium 1, 3 is a cantilever on which the probe electrode 2 is mounted, and 4 is a support for the cantilever 3. The probe electrode 2 can be displaced in the Z-axis direction by the cantilever 3. The medium 1 can be moved by a small amount in the x, y and z-axis directions by the xyz fine movement device 5, and can be further moved by the xyz coarse movement device 6. The cantilever support 4 and the xyz coarse movement device 6 are fixed to a base 7. The base 7 is not shown, but is installed on a vibration isolation table.

The cantilever 3 was formed by using a silicon etching technique. Anisotropic etching technique that utilizes the properties of silicon crystals to a high degree.
A cantilever of SiO _{2 having} a thickness of 1 μm and a thickness of 1 μm was formed. This technique is known [K. E. FIG. Petersen, Pr
oc. IEEE 70 , 420 (1982)]. The probe electrode Z is formed by implanting Si ions into one end of the cantilever 3 of SiO _{2 formed} by the anisotropic etching, and selectively growing a Si crystal on the Si to form a pyramid-shaped crystal 202 having a sharp tip. Thereafter, the conductive layer 201 was formed by evaporating the film to a thickness of 300 ° by an Au vacuum evaporation method.
The xyz fine movement device 5 uses a cylindrical piezoelectric element, and can finely move the recording medium 1 in the x, y and z axis directions by applying an arbitrary voltage.

The xyz coarse movement device 6 uses an xyz stage.

Probe electrode 2 and underlying electrode 1 of recording medium 1
Reference numeral 02 denotes a voltage application and current detection circuit 1 including a voltage application circuit for applying a voltage for recording and erasing and a current detection circuit for detecting a current flowing between the probe electrode 2 and the recording medium 1.
Connected to 0.

The xyz fine movement device 5 and the xyz coarse movement device 6 are driven by control circuits 8 and 9, respectively. These circuits and the voltage application and current detection circuit 10 are connected to the microcomputer 12 and controlled.

The recording medium was prepared as follows.

After cleaning the optically polished glass substrate (substrate 103) using a neutral detergent and trichlene, Cr is deposited as a subbing layer by vacuum evaporation to a thickness of 50 °.
Further, a base electrode (A
u electrode 102) was 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 an aqueous phase at 20 ° C. to form a monomolecular film on the water surface. Wait for the solvent to evaporate,
While increasing the surface pressure of the monomolecular film to 20 mN / m and keeping the surface pressure constant, the electrode substrate was gently immersed at a speed of 5 mm / min across the water surface, and further pulled up.
The Y-type monolayer of the layers was accumulated. By repeating this operation four times, a recording medium 1 having a recording layer 101 in which eight SOAZ layers are accumulated is created.

Next, a specific method of recording, reproducing and erasing will be described.

After the recording medium 1 is fixed on the xyz fine movement device 5, a bias voltage of 100 mV is applied between the probe electrode 2 and the Au electrode 102, and the xyz coarse movement device 6 and the xyz fine movement device 5 are driven to drive the medium. 1 is brought closer to the probe electrode 2. By changing the distance between the probe electrode 2 and the recording medium 1 while monitoring the current flowing between them, a current characteristic (curve indicated by I in the figure) as shown in FIG. 3 was obtained.

On the other hand, when the probe electrode 2 and the recording medium 1 approach each other, a force acts between them, and this force causes the cantilever 3 to move.
Is deformed. Using an optical lever system for detecting the amount of deformation based on the deviation of the reflected beam from the cantilever beam of the laser beam, the result of measurement simultaneously with the current characteristics is also shown in FIG.
(The curve indicated by F in the figure).

In the region a of FIG. 3 where a repulsive force acts between the probe electrode 2 and the recording medium 1, the current flowing between them is almost constant with respect to the distance between them. Therefore, in the subsequent operations, first, the current is monitored by the circuit 10 and the repulsive force (specifically, 10 ⁻⁸⁾ is applied between the probe electrode 2 and the recording medium 1 by the microcomputer 11 under the control of the microcomputer 11.
(Approximately [N]).

In this state, the xyz fine movement device 5 causes the probe electrode 2 to scan the medium 1 by fixing the position of the medium 1 in the axial direction and moving the medium 1 in the x-axis and y-axis directions. During information recording, the circuit 10 applies a voltage equal to or lower than a threshold voltage for turning on the medium at a predetermined position according to the recording information during this scanning. Thus, the medium 1
Information is recorded on top. At the time of erasing (recording of all 0 signals), a voltage higher than the threshold voltage for returning the medium to the OFF state may be applied in the same manner as at the time of recording according to the erasing information. At the time of reproduction, while applying a voltage equal to or lower than the above-described threshold during this scanning, the probe
The current flowing between the medium and the medium 1 is detected. The change state of the detected current at this time indicates information recorded on the medium.

As described above, in the embodiment, the probe electrode 2 is recorded in a state where the tip of the probe electrode and the surface of the recording medium are brought close to a distance where a repulsive force acts between them, and the support of the probe electrode is elastically deformed by the repulsive force. By scanning over the surface of the medium 1 and simultaneously applying a medium change voltage between the probe electrode 2 and the recording medium 1 to perform recording and erasing, and detecting a current flowing through the recording medium by applying a small voltage, the A different area, that is, a recording bit is detected.

Since the support of the probe electrode is used in an elastically deformed state due to the repulsive force acting between the tip of the probe electrode and the surface of the recording medium, if the tip of the probe electrode approaches the surface of the medium due to unevenness on the surface of the medium, the repulsive force increases. The deformation of the support increases, the tip of the probe electrode moves away from the medium surface, and if the probe electrode moves away from the medium surface and the repulsion decreases, the deformation of the support decreases and the probe electrode tip moves closer to the medium surface, If the amount of deformation of the probe electrode support due to surface irregularities during scanning is within the range of elastic deformation, the distance between the probe electrode 2 and the medium surface 1 is determined by mounting an actuator on the support and performing feedback control based on the amount of deformation of the support. Even if it does not, it will be kept almost constant.

Further, in this state, a current signal detected by applying a minute voltage between the probe electrode and the recording medium does not include a current signal due to irregularities on the surface of the recording medium. Becomes possible.

Next, an experiment of recording, reproducing and erasing performed in this apparatus will be described.

While monitoring the detection current, the distance between the probe electrode 2 and the recording medium 1 is brought close to the state shown by the area a in FIG. 3, and in this state, the control circuit 8 of the xyz fine movement device 5 and the xyz coarse movement device 6, 9 is applied, a triangular pulse voltage having a waveform shown in FIG. 4 which is equal to or higher than the threshold voltage V _{th ON} which causes the ON state is applied between the profile electrode 2 and the Au electrode 102 and then again. When a bias of 100 mV was applied and the current was measured, a current of about 8 μA flowed, indicating that the device was turned on.

Next, after applying a triangular pulse voltage having the waveform shown in FIG. 5 which is equal to or higher than the threshold voltage V _{th OFF which} changes from the ON state to the OFF state, 100 m is applied again.
When a bias of V was applied, the current value was about 1 nA.
It was confirmed to return to the OFF state.

Next, in the same manner as described above, with the distance between the probe electrode 2 and the recording medium 1 approaching the state shown by the area a in FIG. 3, the y and z axes of the xyz fine movement device 5 are fixed, and x
When the current was monitored by driving only in the axial direction, the current value showed a constant value of approximately 1 nA. Next, while driving only in the x-axis direction, a triangular pulse voltage having a waveform of FIG. 4 and a threshold voltage V _{th ON} or higher is applied between the probe electrode 2 and the Au electrode 102 at intervals of 10 nm.
Under the constant mV, the driving in the x-axis direction alone was repeated again, and the current flowing between the probe electrode 2 and the Au electrode 102 was measured. It was confirmed that the data was written periodically. Further, the ratio of the current between the ON state and the OFF state also maintained a substantially constant value.

The area where the ON state is periodically written is again scanned only by the x-axis drive, and an arbitrary ON state is turned on.
In a state where the xyz fine movement device 5 is stopped on the state area and this position is held, the threshold voltage V having the waveform of FIG.
A triangular pulse voltage of _{th OFF} or more was applied. Scanning in the x-axis direction alone was repeated, and the current was measured. As a result, it was confirmed that the ON state of the region to which the pulse was applied was erased and the state returned to the OFF state indicating a current of about 1 nA. As in the case of this arbitrary bit erase, the voltage between the probe electrode 2 and the Au electrode is set to be equal to or higher than the threshold value V _{th OFF} , the recording area is scanned, and then the current is measured.
Shows a substantially constant value at about
It was confirmed that all of the N states were erased and turned to the OFF state.

Subsequently, the xyz fine movement device 5 is controlled to 1 nm
When a strap having a length of 1 μm was written at various pitches between 1 μm and 1 μm by the above method and the resolution was measured,
At a pitch of 3 nm or more, a current change of about four digits was always confirmed at the same pitch as the writing pitch, but at a pitch of less than 3 nm, the change of the current amount gradually became smaller.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, the length of 100 μm, the width of 20 μm, and the thickness of 1 μm are formed on one piece of the Si substrate by the method of forming the cantilever and the method of forming the probe electrode used in Example 1.
A plurality of m ₂ SiO ₂ cantilevers are formed, and a probe electrode is provided at the tip of each cantilever.

As shown in FIG. 2, the S
The i-substrate 4 is fixed to the support 13. The support 13 is attached to the base 7 via at least three piezoelectric elements 14. These piezoelectric elements 14 are individually driven by a piezoelectric element control circuit 12 controlled by a microcomputer 11. Voltage application and current detection circuit 1
By 0 ', a voltage is applied to each probe electrode 2, and a current flowing between each probe electrode 2 and the recording medium 1 is separately detected. Other configurations are the same as those used in the first embodiment.

As in the first embodiment, the recording medium 1 having the recording layer 101 composed of eight SOAZ-LB films formed on the Au electrode 102 was fixed on the xyz fine movement device 5. x
The yz coarse movement device 6 and the xyz fine movement device 5 are driven, and a bias of 100 m is applied between the probe electrode 2 and the Au electrode 102.
The two are brought close together with V applied. At this time, the piezoelectric element 14 is controlled so that all the probe electrodes are uniformly applied to the recording medium 1.
, And approach all the probes until the state of the area a in FIG. 3 is reached. In this state, the same recording, reproduction, and erasing operations as in the first embodiment are performed on each probe electrode 2 while the medium 1 is moved in the xy directions by the xyz fine movement device 5.

Next, an experiment in this apparatus will be described. Under the above-mentioned approaching state, the xyz fine movement device was controlled to measure the current flowing between each probe electrode 2 and the Au electrode 102 while driving the recording medium in the xy plane. The current values on the order of magnitude were small, and the fluctuations in the current flowing through the individual probe electrodes during scanning were extremely small.
Next, the recording operation will be described with reference to FIG. As described above, while driving the recording medium in the xy plane, a write pulse train as shown in FIG. 6B is generated for each probe electrode based on individual bit information (FIG. 6A). And added to this. Here, the first bit of the bit information is set as a bit corresponding to the ON state for all the individual bit information (indicated by a-1 in the figure). After the pulse application, the recording medium was driven again in the xy plane in the same manner as in the writing, and the current flowing between the probe electrode 2 and the Au electrode 102 was measured under the condition of applying a bias of 100 mV. Is obtained for each probe electrode, and a pulse train obtained by binarizing these current measurement values is individual bit information added to each probe electrode 2 ((a) in FIG. 6).
Matched.

Next, an erase pulse train as shown in FIG. 6C was generated based on the individual bit information written above. Here, it is assumed that the first bit of all the bit information remains ON and is not erased. The recording medium was driven in the xy plane in the same manner as when writing, the current value was measured, and the drive of the medium was temporarily stopped at the first bit, that is, at the position where the current value first changed by about four digits. At this time, a change of about four digits was observed in all the probe electrodes 2 according to the condition of the bit information determined first. Subsequently, the drive of the medium was restarted, and in synchronization therewith, individual erase pulse trains were applied to the individual probe electrodes 2 generated earlier. Again, the recording medium 1 is written in the same manner as when writing.
Was driven in the xy plane and the current was measured. All but the first bit showed an OFF state, that is, a current value of about 1 nA, and it was confirmed that erasing was completed.

Instead of the erase pulse used here, of the bit information used for writing, except for the first bit,
An arbitrary pulse was selected to generate an erase pulse train ((d) in FIG. 6), and an erase experiment was performed in the same manner as described above. As a result, it was confirmed that only the selected bit was erased.

Next, a third embodiment will be described.

Using the polyimide monomolecular accumulation film as the recording layer 101, the same recording, reproducing and erasing experiments as in Examples 1 and 2 were performed. The method for forming the polyimide monomolecular cumulative film is described below.

[0057]

[Outside 1]

After dissolving the polyamic acid represented by the formula (1) (molecular weight: about 200,000) in an N, N-dimethylacetamide solvent (concentration in terms of monomer: 1 × 10 ⁻³ M), N, N separately adjusted 1-Dimethylhexadecylamine in the same solvent
× 10 ⁻³ M solution and 1: 2 (V / V)
A polyamic acid hexadecylamine salt solution represented by the formula (2) was prepared. This solution was spread on an aqueous phase composed of pure water at a water temperature of 20 ° C. to form a monomolecular film on the water surface. After removing the solvent, the same electrode substrate used in Example 1 was gently immersed at a speed of 5 mm / min in a direction crossing the water surface while increasing the surface pressure to 25 mN / m and keeping the surface pressure constant. Then, gently pull up at 5 mm / min to make two layers of Y
A monomolecular cumulative film was prepared. This operation was repeated six times to accumulate 12 monolayers. Next, this substrate is
A heat treatment was performed at 0 ° C. for 10 minutes to imidize polyamic acid hexadecylamine salt (formula (3)) to obtain a polyimide single molecule cumulative film.

[0059]

[Outside 2] The same recording, reproduction, and erasing as in Examples 1 and 2 could be performed on the recording medium 1 created as described above.

In the embodiment described above, the recording layer 101
The LB method has been used for the formation of a film. However, any film forming method capable of forming an extremely thin and uniform film can be used without being limited to the LB method. Specifically, a vacuum deposition method such as an MBE method or a CVD method is used. Is mentioned.

In addition to other organic compounds containing a π-electron conjugated system, usable materials can be extended to inorganic materials such as chalcogen compounds, as long as they can change the conductive state by voltage application.

Furthermore, it is also possible to use a semiconductor as the recording medium side electrode and to integrate the electrode and the recording layer.

The present invention does not limit the substrate material, its shape and its surface structure at all.

On the other hand, as long as the material of the probe electrode is conductive, it can be applied to the present invention. Further, a wire, for example, a platinum wire, which is bent to 90 ° C. so as to also serve as a cantilever, can be used. SiO used as an elastic member
The cantilever ₂ is not limited to this, and various shapes such as a double-supported beam and a thin film structure can be considered. Au, Ni, SuS, BeCu foil, etc. can be used as a material. In any case, it is necessary to shift by a small force.

Although the xyz fine movement device uses a cylindrical piezoelectric element, a tri-pot type piezoelectric element or a bimorph type piezoelectric element can also be used.

Each embodiment may be an apparatus for recording only or reproducing only.

[0067]

According to the present invention described above, the reproduction signal is hardly affected by irregularities on the surface of the recording medium, and a change in the applied voltage during recording does not affect the distance control between the probe electrode and the recording medium. In addition, a recording and / or reproducing apparatus having a simple configuration is realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing an information recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically illustrating an information recording / reproducing apparatus according to a second embodiment of the present invention having a plurality of probe electrodes.

FIG. 3 is a characteristic diagram showing a change in a current flowing between the probe electrode and a recording layer surface and a force acting between the two obtained when a distance between the probe electrode and the recording layer surface is changed.

FIG. 4 is a pulse voltage waveform for recording.

FIG. 5 is a pulse voltage waveform for erasing.

FIG. 6 shows bit information, a recording pulse train, and an erasing pulse train given to one probe electrode in a recording, reproducing, and erasing experiment using a plurality of probe electrodes.

FIG. 7 is a diagram showing M in which a recording layer used in the present invention is sandwiched between metal electrodes.
It is a structure schematic diagram of an IM element.

FIG. 8 shows current-voltage characteristics obtained with the device of FIG.

FIG. 9 is a current-voltage characteristic showing a memory effect obtained by the device of FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 recording medium 2 probe electrode 3 cantilever 4 cantilever support 5 xyz fine movement device 6 xyz coarse movement device 7 base 8 xyz fine movement device control circuit 9 xyz coarse movement device control circuit 10 voltage application and current detection circuit Reference Signs List 11 microcomputer 12 control circuit for piezoelectric element 13 support base 14 piezoelectric element

Continued on the front page (72) Inventor Kunihiro Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 9/00 G11B 9 / 04 G01N 37/00

Claims (6)

(57) [Claims] An apparatus for recording and / or reproducing information on and from an information recording medium via a probe, wherein a force for deforming an elastic member supporting the probe in a direction for correcting a variation in the distance between the probe and the information recording medium. Controls the distance between the probe and the information recording medium by arranging the probe and the information recording medium so as to act between the probe and the information recording medium, and applies a voltage between the probe and the information recording medium in the controlled state. A recording and / or reproducing apparatus for performing information recording and / or reproducing by detecting a current between the probe and the information recording medium. 2. The recording and / or reproducing apparatus according to claim 1, wherein an interatomic repulsion between the probe and the information recording medium is used as the force acting between the probe and the information recording medium. 3. The recording and / or reproducing apparatus according to claim 1, wherein there are a plurality of said probes, each of which is supported by an elastic member. 4. The recording and / or reproducing apparatus according to claim 1, wherein reproduction is performed by detecting an electric characteristic of the information recording medium by detecting a current between the probe and the information recording medium. 5. The recording and / or reproducing apparatus according to claim 1, wherein recording is performed by changing an electric characteristic of the information recording medium by applying a voltage between the probe and the information recording medium. 6. An apparatus for recording and / or reproducing information via a probe facing an information recording medium, wherein an elastic member supporting the probe is deformed so that a distance between the medium and the probe is variable. In a close arrangement state in which a force acting between the medium and the probe is generated, the distance between the medium and the probe is controlled by a balance between the acting force and the elastic force of the elastic member. A recording and / or reproducing apparatus for recording information by applying a voltage to the medium and / or performing reproduction by detecting a current between the probe and the medium.