JP3000496B2 - Information recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates are those which relate to large and high-density information recording method having a recording density of the nm order.

[0002]

2. Description of the Related Art In recent years, the use of memory materials is at the core of the electronics industry such as computers and related equipment, video disks, digital audio disks, and the like, and the development of such materials has been very active. The performance required for the memory material varies depending on the application, but in general, a material having a high density and a large recording capacity is required.
Until now, semiconductor memories and magnetic memories using magnetic materials or semiconductors as the main material were mainly used. However, with the advancement of laser technology, optical memories have been developed in recent years. Thus, high-density recording and reproduction on the order of μm has become possible.

As such a recording medium, a thin film of a metal or a metal compound, a thin film of an organic dye, or the like is used. A hole is formed by evaporating or melting using heat of a laser beam, or information is changed by changing a reflectance. Have recorded.

[0004] Further, at present, the use of video information is rapidly progressing, and there is an increasing need for smaller and larger-capacity high-density memories.

[0005]

However, in the conventional optical memory, since laser light is converged by an optical system for recording / reproducing, it is difficult to narrow the beam diameter to less than the wavelength of light, and light having a shorter wavelength is used. However, the recording density is limited to the order of μm.

An object of the present invention is to achieve a large-capacity, high-density information recording / reproducing / erasing information having a recording density on the order of nm, which has not been achieved by the above-mentioned information processing apparatus using the conventional optical memory. It is to provide a method .

[0007]

SUMMARY and operation for solving] The present invention, in opposition to the flat electrode, a recording medium obtained by forming an organic film having a large central metal atom in the thickness direction from the multidentate ligand-flop
A lobe electrode is placed between the probe electrode and the plane electrode.
By applying a voltage to the center according to the information
Two metal atoms with different distances from the surface of the planar electrode
And record information by moving between the positions
The organic film is a lead cover.
Consisting of a Russiannin or lead phthalocyanine derivative
This is a featured information recording method.

According to the present invention, in the organic film recording medium, it is possible for the central metal atom to be at least at the first position and the second position with respect to the plane electrode surface. For example, a positive or negative voltage is applied between the probe electrode and the plane electrode, and a first position at which the central metal atom protrudes from the molecular surface of the organic film recording medium to a side closer to the plane electrode; Is moved to and from a second position protruded to the far side from the flat electrode, thereby controlling the distance between the central metal atom and the flat electrode surface, and further using a normal scanning tunneling microscope (hereinafter, “STM”). By performing substantially the same operation as the observation of the organic molecular surface in the order of nm, which is the operation described in (1), large-capacity, high-density recording, reproduction, and erasing with a recording density in the order of nm can be performed.

Examples of the organic film recording medium suitably used in the present invention include lead phthalocyanine, lead phthalocyanine derivative, lead porphyrin and lead porphyrin derivative. Metal phthalocyanine, metal polyfin and the like having a small metal can be applied. Further, any of these monomolecular films and monomolecular cumulative films can be applied, but the film thickness is desirably as thin as possible, and preferably in the range of several to 100 degrees.

As a method for forming an organic film recording medium on a flat electrode, a vapor deposition method, a cluster ion beam method and the like can be specifically applied, but from the viewpoint of controllability, easiness and reproducibility. Among the known prior arts, the Langmuir-Blodgett method (hereinafter, referred to as “LB method”) is very suitable, and the forming method does not limit the present invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

Embodiment 1 FIG. 1 is a schematic diagram showing the features of the information recording method of the present invention best. In the figure, 1 is an organic film recording medium, 2 is a plane electrode, and the organic film recording medium 1 can control the distance between the central metal atom or the central metal atom group constituting the medium and the surface of the plane electrode 2. Things.

Reference numeral 3 denotes a substrate for manufacturing a flat electrode, and 6 denotes a flat electrode.
A Z-movable piezo-electric actuator, which is a means for controlling the distance between the probe electrode 6 and the surface of the organic film recording medium 1;
Reference numerals 8 and 9 denote means for scanning the probe electrode 6 along the surface of the organic film recording medium 1. Piezoelectric actuators movable in the X and Y directions. Reference numeral 10 denotes a tunnel current flowing between the probe electrode 6 and the plane electrode 2. Is a means for detecting Reference numeral 11 denotes a low-pass filter that mainly removes a noise component of the tunnel current signal detected by the current detection means 10, reference numeral 12 denotes a band-pass filter that extracts an information signal at the time of information reproduction operation, and reference numeral 13 denotes a flat surface between the probe electrode 6 and the plane at the time of information recording operation. A means for applying a voltage between the electrodes 2;
Reference numeral 4 denotes a microcomputer that controls the entire information processing apparatus.

In this embodiment, Pb tetra-4-tert-butyl-phthalocyanine is used as the organic film recording medium 1.

[0015]

Embedded image A monomolecular film was formed on the flat electrode 2 using a LB method as a film forming method.

Specifically, xylene is used as a solvent to form Pb
A solution of 4.7 × 10 ⁻⁴ mol / l of tetra-4-tert-butyl-phthalocyanine was prepared, and developed on pure water using a Teflon LB trough to obtain 19 mN / m 2.
Up to the surface electrode 2 while maintaining the surface pressure.
Was moved vertically to the surface of pure water to form a monomolecular film.

In the case of lead phthalocyanine and lead phthalocyanine derivatives, which are preferably used as the organic film recording medium of the present invention, the ionic radius of the central metal atom is generally large. And a molecular surface is curved in an umbrella shape (shuttle cock structure). By applying a positive or negative voltage between the probe electrode 6 and the plane electrode 2, the central metal atom is moved from the molecular plane to the plane electrode 2. And a second position (5 in the figure) where the central metal atom is raised from the molecular plane to a side farther from the plane electrode 2.
It is possible to move between them.

In this manner, the distance between the central metal atom or atomic group in the molecule of the organic film recording medium 1 and the surface of the plane electrode 2 is determined by the distance dm1 when the central metal atom is brought closer to the plane electrode 2 or the central metal atom. Distance dm2 away from plane electrode 2
In addition, an experiment of recording, reproducing, and erasing information in the order of nm by performing substantially the same operation as the observation of the organic molecular surface in the order of nm, which is a normal STM operation, was performed.

Experiments for recording and erasing information are as follows.
First, using the above-mentioned organic film recording medium,
Thus, a bias voltage of +100 mV is applied between the probe electrode 6 and the plane electrode 2 so that the plane electrode 2 has a high potential. Then, the tunneling current is detected by the current detecting means 10, and the surface of the probe electrode 6 and the surface of the organic film recording medium 1 are adjusted so that the tunneling current becomes 20 pA with a low frequency signal of the tunneling current obtained by using the low-pass filter 11. The probe electrode 6 of the organic film recording medium 1 is moved by the piezo-electric actuators 8 and 9, which are scanning means, while the piezo-electric actuator 7, which is a scanning unit, performs feedback control of the distance to the piezoelectric film actuator 7, which is movable in the Z-direction. Access was made above the desired molecular location on the surface. Next, the Z-direction feedback control of the probe electrode 6 is temporarily stopped, and the voltage
Pulse voltage is +3 V or -3 V in μsec to 1 sec
Was applied between the probe electrode 6 and the plane electrode 2. As a result, the central metal atom is
It can be reversibly moved between the second positions, and recording and erasing of information has been realized.

Next, an information reproduction experiment was performed on the organic film recording medium used in the above-described recording and erasing experiments. Specifically, +100 m is applied between the probe electrode 6 and the plane electrode 2 by the voltage applying means 13 so that the plane electrode 2 has a high potential.
A bias voltage of V is applied. Then, the tunneling current is detected by the current detecting means 10, and the surface of the probe electrode 6 and the surface of the organic film recording medium 1 are adjusted so that the tunneling current becomes 20 pA with a low frequency signal of the tunneling current obtained by using the low-pass filter 11. The probe electrode 6 is moved by the piezo-electric actuators 8 and 9, which are scanning means, while the distance between the probe electrode 6 and the organic film recording medium 1 is controlled by a piezo-electric actuator 7, which is a scanning unit, while controlling the distance to the piezoelectric actuator 7, which is movable in the Z-direction. Scan along the surface of.
Next, the reproduced information signal component of the tunnel current at this time was extracted by the bandpass filter 12.

As a result, the information written in the above-described recording and erasing experiments could be reproduced with good reproducibility.

Example 2 This example is the same as Example 1 except that a monomolecular cumulative film of lead phthalocyanine was used as the organic film recording medium.
As a result, in the same manner as in Example 1 using a monomolecular film, information on the order of nm can be recorded and erased on the organic film recording medium, and the information written in the recording and erasing experiments can be reproduced in the reproduction experiment. I was able to play well.

In the first and second embodiments, the method of forming the organic film recording medium 1 on the
The film forming method is not limited to the LB method. For example, in the case of lead phthalocyanine, sublimation purification is repeated three times, and the lead phthalocyanine is used as a raw material in an amount of 10 to 100 ° C. by vacuum evaporation. It can be thinned to a film thickness of The deposition conditions at this time are, for example, 10 ^−6.
The substrate temperature is set to room temperature or 100 ° C. under a vacuum of Torr or less.
, And set the vapor deposition source temperature to 450 to 550 ° C. to 0.1 to
The deposition rate can be 1 nm / sec.

Further, as the plane electrode 2, for example,
Precious metals such as Au, Ag, Pt, and Pd are 10 ^-6 Torr
Under the following vacuum, keep the substrate temperature at 100 to 400 ° C,
About 500 to 100 at a deposition rate of 0.1 to 1 nm / sec
It is also possible to use a deposited film deposited to a thickness of 0 °.

Further, as the flat electrode forming substrate 3, for example, a glass substrate, a mica substrate, a Si substrate or the like can be used.

[0026]

As described above, according to the present invention, large-capacity, high-density recording, reproduction, and erasing having a recording density on the order of nm, which has not been achieved by an information processing apparatus using a conventional optical memory, can be performed. An information recording method was realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an information processing apparatus for explaining an information recording method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Organic film recording medium 2 Plane electrode 3 Plane electrode manufacturing substrate 4 First position 5 Second position 6 Probe electrode 7 Z direction movable piezoelectric actuator 8, 9 X, Y direction movable piezoelectric actuator 10 Current detection Instrument 11 Low pass filter 12 Band pass filter 13 Voltage applying device 14 Microcomputer

Continued on the front page (72) Inventor Kazusa Kawade 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Etsuro Kishi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon stock In-company (72) Inventor Toshihiko Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (56) References JP-A-63-161553 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 9/00

Claims (2)

(57) [Claims] To 1. A plane electrode, arranged probe electrode to face the serial <br/> recording medium obtained by forming an organic film having a large central metal atom from the polydentate ligand in the thickness direction, The probe
By applying a voltage between the poles and the plane electrode,
The central metal atoms are separated from the surface of the planar electrode
To move information between two positions with different distances
Performing an information recording method. 2. The method according to claim 1, wherein the organic film is made of lead phthalocyanine or lead.
Claims characterized by comprising a phthalocyanine derivative
2. The information recording method according to 1.