JP2927678B2 - How information is recorded - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic pattern and a memory device. More specifically, the present invention relates to an atomic pattern and a memory device using the same, which are useful for creating an ultra-high-density and large-capacity storage device.

[0002]

2. Description of the Related Art Heretofore, as a storage element for storing information as some physical state, a flip-flop circuit or a storage element utilizing the distinction of the magnetization direction of a magnetic material has been used. A flip-flop circuit is a type of multivibrator and has two stable states in operation. It is implemented on an integrated circuit such as a transistor or IC / LSI, and is mainly used as a binary counter circuit and a computer register. It is used for

A device using a magnetic material is realized as a magnetic storage device represented by a magnetic tape, a magnetic disk, or the like, and stores information according to a difference in magnetic direction. However, up to now, the performance of storage devices using these conventional storage elements has reached the limit, and a dramatic increase in storage capacity cannot be expected.

An object of the present invention is to provide a completely new storage device which can overcome the above-mentioned limitations of the conventional technology and can realize a high-density and large-capacity storage capacity.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a voltage pulse is applied between a fine probe and a substrate to extract one unit of a substrate constituent atom from the substrate surface. in, or recording method of the information of one substrate constituent atoms of the unit is pulled out from the substrate surface and atomic information element by patterning by supplying to the substrate surface
Supply atoms to the atomic defects on the substrate surface,
Removes and removes the supplied atoms again, causing surface defects.
A method of recording information characterized by preventing the influence of noise .

[0006]

[0007]

In other words, according to the present invention, when a voltage pulse is applied between the fine probe constituting the STM (scanning tunneling microscope) and the substrate, the atoms are extracted and supplied one by one, and furthermore, the supplied atoms are removed. Re-removal can be performed, and by utilizing the extraction and supply of these atoms, a specific atomic pattern consisting of one or several atoms can be created.
The present invention has been completed based on the finding that a memory in an atomic unit can be constructed by the formed pattern.

FIG. 1 is a conceptual diagram showing how atoms are extracted and supplied in the present invention. That is, first, as shown in FIG. 1A, the STM probe (1) stores the atoms constituting the substrate (3) extracted from the substrate (2). The method uses an STM under almost vacuum conditions.
A voltage (V1) is applied to the probe (1) to dissociate the atoms (3) constituting the substrate, and this is stored on the surface of the STM probe (1).

Then, as shown in FIGS. 1B and 1C, the voltage applied to the STM probe (1) is increased (V2: V1 <V2), and the STM probe (1) The substrate constituent atoms (3) stored on the surface are subjected to electric field evaporation, and the electric field evaporated substrate constituent atoms (3) are locally localized on the surface of the substrate (2) or a defective portion on the surface of the substrate (2). Is vapor deposited. Thus, a predetermined atomic pattern is formed. This atomic pattern acts as an information recording memory. Therefore, a highly integrated storage device at the atomic level is configured.

According to the present invention, by supplying atoms to defects (vacancies) and removing the supplied atoms again, not only the influence of noise due to surface defects can be prevented, but also the memory contents can be modified. , Erasing, and rewriting are enabled. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0011]

EXAMPLE 1 A Si (111) substrate cut from a P-doped n-type Si wafer (0.1 Ωcm) into a size of 15 × 7 × 0.3 mm ³ was used. 5 × 10 ^-9 Pa
Scanning tunneling microscope (JE)
(OL JSTM-4000XV). Next, the substrate was heated and washed at 1250 ° C. in a vacuum of 3 × 10 ⁻⁸ Pa or more. In addition, a tungsten single crystal having a diameter of 0.25 mm was used for the STM probe. The STM tip has a [111] crystal axis direction by electric etching using 1N KOH.

FIGS. 2 (a) and 2 (b) show STM photographs of Si atoms re-supplied solely on the Si (111)-(7 × 7) substrate surface. FIGS. 2A and 2B
Is a surface STM image of a region including another Si atom, which is represented by a re-supplied crosshair when one Si atom is taken out from the substrate surface. The voltage pulse adapted for this substrate material was -6 V, 10 ms. At this time, the tunnel current was 0.6 nA.

From FIGS. 2A and 2B, the extracted S
It can be seen that the i atom is contained in the missing atom. Example 2 Using the same Si substrate and STM probe as in Example 1,
Supply and extraction of Si atoms continuous in a chain were performed on the (111)-(7 × 7) substrate surface.

FIG. 3A shows the Si (111)-(7 × 7) surface ST in a state before the series of Si atoms are taken out.
It is an M image. The circle shown in this STM image is a mark indicating a naturally defective portion. The STM image at this time shows five voltage pulses (−5.5 V,
30 ms) and taken out after taking out Si atoms. The tunnel current at this time is 0.6
nA.

Next, the STM probe is moved from the upper left to the lower right in FIG. 3A at a speed of about 0.5 nm / s, and three voltage pulses (-5.5 V, 30 ms) during the movement. Was added. This indicates that a chain composed of three Si atoms was generated, as indicated by the crosshairs in FIG. 3B. Each of the supplied Si atoms was arranged at the position where the voltage pulse was applied with an accuracy of about ± 0.5 nm.

Next, an attempt was made to remove these three arranged Si atoms. At this time, the set voltage pulse is −5.5 V, 30 ms. This result is shown in FIG.
(C). From FIG. 3 (c), the supplied 3
It can be seen that two Si atoms have been completely removed. Example 3 Using the same Si substrate and STM probe as in Example 1,
An attempt was made to supply many Si atoms in the local region on the (111)-(7 × 7) substrate surface.

First, Si (111)-(7 × 7)
At another position on the substrate surface, 15 voltage pulses (−5.5
V, 30 ms), and Si atoms were taken out on the STM probe. Next, the STM tip was moved to another location, and 15 voltage pulses (-5.5 V, 30 ms) were applied to supply Si atoms. The resulting STM image is shown in FIG. At this time, the supplied Si atoms are 26.

FIG. 4 shows that most of the Si atoms are supplied to the positions indicated by the small black dots. FIG.
The portion represented by a white triangle in the inside is this Si (1
11) represents the center of a corner hole having a (7 × 7) structure. Example 4 Using the same Si substrate and STM probe as in Example 1,
S is present on the (111)-(7 × 7) substrate
An attempt was made to supply i atoms.

FIG. 5A is an STM image of the Si (111)-(7 × 7) surface with the Si atom deficient. The portion represented by a circle in FIG. 5A is a portion that is characteristically missing. First of all, Si
Five voltage pulses (−5.5 V, 30 ms) were applied at another position on the (111)-(7 × 7) surface, and Si atoms were taken out on the STM probe. Next, the STM probe is moved to the position of the Si atom deficient portion indicated by the arrow in FIG.
Five voltage pulses (-5.5 V, 30 ms) were applied to supply Si atoms to the deficient portions. The results are shown in FIG.

From FIG. 5B, in FIG.
The missing portion represented by the open triangle is white in this figure, indicating that Si atoms have been supplied to the missing atom portion.

[0021]

As described above in detail, according to the present invention, by supplying atoms to defects (vacancies) and removing the supplied atoms again, the influence of noise due to surface defects can be prevented. This makes it possible to correct, erase, and rewrite the stored contents. Furthermore, application to electronic devices and recording materials to be miniaturized becomes possible.
An ultra-large capacity storage device can be realized.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b) and 1 (c) are schematic views showing the principle of the present invention.

FIGS. 2 (a) and 2 (b) are photographs instead of drawings showing the state of a substrate surface as an example of the present invention as an STM image.

FIGS. 3A, 3B, and 3C are photographs instead of drawings showing the state of a substrate surface as an example of the present invention as an STM image.

FIG. 4 shows the state of the substrate surface as an embodiment of the present invention;
It is a photograph in place of a drawing shown as a TM image.

5 (a) and 5 (b) are photographs instead of drawings showing the state of the substrate surface as an example of the present invention as an STM image.

[Explanation of symbols]

 1 STM probe 2 Substrate 3 Substrate constituent atoms

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G11B 9/00 G01N 37/00

Claims (1)

(57) [Claims] We claim: 1. applying a voltage pulse between the fine probe and the substrate, by pulling the substrate constituent atoms of the single units from the substrate surface, or the substrate substrate constituent atoms of one unit is pulled out from the substrate surface it atom by patterning by supplying to the surface recording method of information of an information element
Supply or supply atoms to the atomic defects on the substrate surface.
The supplied atoms are pulled out again and removed, and the
A method for recording information characterized by preventing the effects of noise .