JPH0730093A - Buried atom thin wire - Google Patents

Abstract

PURPOSE:To prevent the arrangement of atoms from being disordered due to the effect of a temperature or the like by a method wherein the atoms, which constitute a device, are buried in a groove, which is formed in a crystal face and has a depth and a width of the amount of one piece of an atom to the amount of a plurality of pieces of atoms, and an atom thin wire is formed into a structure where the atom thin wire can stably exist in the crystal face. CONSTITUTION:The surface atoms of atoms 21 constituting a substrate crystal are pulled out and a small groove 22 is formed. Then, atoms 23, which are used for forming an atom thin wire, are made to attract on the substrate surface, a voltage pulse is applied to a probe and the atoms 23 are diffused, whereby the atoms 23 are buried in the groove 22. The probe is moved to other region, a voltage pulse is again applied to the probe to diffuse the attracted atoms 23 left in the vicinity of the groove 22 to other region and the atoms 23 are removed. As this result, attracted atoms 24 in the groove 22 are arranged, are left into a thin linear form and the atom thin wire 25 is formed. As the wire 25 is buried in the groove formed in the surface of the substrate crystal and can stably exist in the substrate surface, it is used as the smallest electronic circuit constituent element, which is though in principle, and a far higher-density circuit can be constituted compared to an integrated circuit formed using a conventional process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates not only to ultra-high-density wiring technology, but also to a method of constructing an ultra-high-density integrated circuit combined with an element composed of a plurality of atoms.

[0002]

2. Description of the Related Art It is generally known that the minimum processing dimension of the fine processing technology in the conventional integrated circuit construction technology is 0.1 .mu.m. Has been proposed (Japanese Patent Application No. 3-340649). In this invention, a switching device is configured by arranging atoms on a crystal plane to propose an ultra-high integration and ultra-high density device.

[0003]

In a device constructed by arranging atoms on a crystal plane, the atomic arrangement may be disturbed by the influence of temperature and the like, and it may be difficult to obtain desired characteristics. In the state, it is a problem to make it exist stably.

[0004]

In order to realize the stable existence of the above atomic switching device on the crystal plane, in the present invention, atoms constituting the device are embedded in a groove formed on the crystal plane, Alternatively, by covering with another atom, a means for removing the influence of thermal disturbance or the like is provided.

[0005]

The principle of the atomic thin wire disclosed in the present invention will be described with reference to FIG. FIG. 1A shows an insulating or semiconductor substrate 12
It is a top view which shows the conductive atomic thin wire 11 formed above. As shown in the sectional view (b) of (a) in AA ′, the atomic thin wires 11 are embedded in the grooves formed on the crystal surface of the substrate 12, and can stably exist on the substrate surface. This is the smallest possible electronic circuit component in principle.

[0006]

【Example】

(Embodiment 1) This embodiment discloses a method of realizing an atomic thin wire. Atomic operation is performed by scanning tunneling microscope (ST
M) (for details on STM, see
G. Binnig, H. Roller, Physical Review Letters, Volume 49, Item 57, 1982 (G. Binnig, H. Rohrer, Ph
ys. Rev. Lett., 49 , 57 (1982))). In the STM, it is possible to extract individual atoms from the crystal surface by a voltage applied to the probe while the probe and the sample substrate are brought close to each other to the extent that a tunnel current is detected. For example, molybdenum disulfide (MoS ₂ ) has been reported to extract S atoms on the crystal surface by applying a voltage pulse of -5.0 V to the probe (S-Hosoki, Applied Sapphire). -Fest Science,
Volume 60/61 Paragraph 643 1992 (S.Hosoki, Appl.Surf.Sci., 60/61 , 6
43 (1992))). Further, when there are weakly bonded adsorbed atoms on the surface of the substrate, it is also possible to induce surface diffusion by applying a voltage to the probe so that the adsorbed atom is attracted directly below the probe. For example, gallium arsenide (GaA
s) It has been reported that cesium (Cs) atoms adsorbed on the substrate gather under the probe when a −3.0 V pulse is applied to the probe (El Jay Whitman, Physical. Review Letters Volume 66 Item 1338 1991
Year (LJ Whitman, Phys. Rev. Lett., 66 , 1338 (1991))).

The procedure for actually realizing the atomic thin wire will be described with reference to FIG. 2 (a1) (b1) (c1)
(D1) is a plan view of the substrate crystal seen from above, and (a)
2) (b2) (c2) (d2) are (a1)
It is sectional drawing in AA 'of (b1) (c1) (d1). First, the surface atoms of the atoms 21 constituting the substrate crystal are extracted, and the narrow groove 22 as shown in FIGS.
To form. Atom 2 shown in bold in the plan view of FIG.
1 represents what is present on the surface, and the other one represents what is present in the second layer and below.

Next, the atoms 23 forming the atomic thin wires are adsorbed on the surface of the substrate (FIGS. 2 (b1) and (b2)), and a voltage pulse is applied to the probe on the narrow groove 22 to diffuse it, whereby the fine groove 22 is formed. This atom 23 is embedded (Fig. 2 (c1) (c
2)). Further, the probe is moved from the narrow groove 22 to another region, a voltage pulse is applied again, and the adsorbed atoms 23 remaining in the vicinity of the narrow groove 22 are diffused to another region. Remove. Since the adsorbed atoms 24 embedded in the narrow groove 22 are more in contact with the substrate atoms and are more stable than the adsorbed atoms 23 on the substrate, as a result, only the adsorbed atoms 23 on the substrate diffuse, Removed,
The adsorbed atoms 24 in the narrow groove 22 are arranged and remain in a thin line shape, and
Atomic thin wires 25 as shown in (d1) and (d2) are formed.

The shape of the atomic thin wire is not generally required to be a single straight line, and is the most stable shape due to the interaction between the substrate and the thin wire atom, for example, the zigzag structure shown in FIG. A chain composed of a plurality of thin wire atoms 32 may be formed on the crystal substrate 31. Also in FIG. 3, FIG.
As in the plan view, the thick-lined atoms 31 represent those existing on the surface, and the other atoms represent those existing in the second or lower layer. Although the fine wire atoms 32 are regularly arranged in this embodiment, the same effect can be obtained by a random arrangement.

The atomic radius of the fine wire atom 24 is optimal when it is substantially equal to the width of the fine groove 22, but it can be embedded inside the groove even when the atomic radius is larger than the groove width, and when it is small. Closely packed.

Since the STM cannot be applied to an insulating sample, as a concrete method for realizing the embedded atomic thin wire, a semiconductor such as silicon (Si) is used as a substrate.
By using an alkali metal such as cesium (Cs) as the conductive atom to form an atomic thin wire at room temperature and cooling it to, for example, liquid nitrogen temperature (77K),
It is possible to use only the substrate by insulating it.
The substrate temperature can be selected from an appropriate value between several μK and several hundred K depending on the conductivity of the substrate and the atomic wires.

(Embodiment 2) This embodiment shows an embodiment relating to an atomic thin wire using a plurality of kinds of atoms. The fine wire atom is not limited to one type, and a plurality of types of atoms may be used. By using a plurality of types of atoms having different chemical or physical properties, it is possible to change the electric conductivity of the atomic wire or to construct an element that requires a plurality of atoms having different transfer characteristics as shown in Example 3. It becomes possible. When using multiple types of atoms in a single atomic thin wire, first fill the narrow grooves with one kind of thin wire atom, then draw out the necessary number of thin wire atoms, adsorb and diffuse different kinds of thin wire atoms, and then re-use narrow grooves. To fill. By repeating this, it becomes possible to realize an atomic thin wire composed of atoms of an arbitrary type. As another method, a plurality of atomic species may be adsorbed on the substrate surface, and a voltage pulse may be applied to the probe to realize an atomic thin wire composed of a plurality of atomic species. Furthermore, by embedding a plurality of types of atoms that easily form bonds with each other in the groove at the same time, it is possible to form an atomic thin wire having a constant composition.

FIG. 4 shows an example of an atomic thin wire containing two kinds of atoms 42 and 43 formed on the substrate crystal 41. Also in this case, the sequence may have a zigzag structure, a multi-chain structure, or a random structure. In FIG. 4 as well, as in the plan view of FIG. 2, the atoms 31 indicated by thick lines represent those existing on the surface, and those that do not exist represent those existing in the second layer and below.

(Embodiment 3) This embodiment shows the structure of a switching element to which an atomic thin wire is applied. FIG. 5 shows an example of the switching element. In FIG. 5, only the outermost surface atoms are shown. Atomic wire 51, switching electrodes 52, 53, switching atom 54, guide atom 5
5 and substrate atoms 56. High on the electrode 52
Either the h voltage or the Low voltage is applied, and the intermediate value of both voltages is always applied to the electrode 53.
The direction of the electric field generated between both electrodes changes depending on the voltage applied to 2. Further, a switching atom 54 is arranged between both electrodes, and if a guide atom 55 adjacent to this is selected to have a relatively small interaction with the switching atom 54, the switching atom 54 will move between the electrodes due to the electric field. It will be possible. The movement of the switching atom 54 causes a switching action on the atomic thin wire 51.
That is, when the switching atom 54 is in the atomic thin wire 51, it is in the ON state (FIG. 5A), and when it is not in the OFF state.
A state (FIG.5 (b)) is shown. Further, without applying an intermediate voltage to the electrode 53, a high voltage is applied to the electrode 52 to move the switching atom 54 to turn it on, and the electrode 53 is driven to a high voltage.
It is also possible to apply the h voltage and turn it off. There may be a plurality of switching atoms 54, and the atomic thin wires 51
It may be an atom of the same kind as the atom constituting the. The guide atom 55 may be the same kind of atom as the substrate atom 56. For example, as the substrate, a semiconductor such as silicon (Si), gallium arsenide (GaAs), molybdenum disulfide (MoS ₂ ) or an insulator such as aluminum oxide (Al ₂ O ₃ ) or magnesium oxide (MgO) is used. As the thin wire, a metal atom such as sodium (Na), magnesium (Mg), gold (Au), iron (Fe), or copper (Cu) is used as the thin wire, but it basically shows conductivity. Any material will do. Good characteristics were obtained especially when gold was used. As the switching atom, an atom that can easily move on the surface can be used. For example, metal atoms such as potassium (K) and cesium (Cs), or xenon (X
Atoms having a small interaction with the substrate such as e) are suitable.
Further, as the guide atom, a semiconductor or an insulator is suitable like the substrate. Good switching characteristics were obtained when atomic thin wires made of gold (Au) atoms were formed on a silicon (Si) substrate and cesium (Cs) was used as switching atoms and silicon (Si) was used as guide atoms. .

(Embodiment 4) This embodiment discloses an embodiment of an atomic thin wire whose surface is covered with other atoms. FIG. 6A is a sectional view taken parallel to the atomic thin line 63, and FIG. 6B is a sectional view taken along AA ′ perpendicular to the atomic thin line 63. By covering the atomic fine wires 63 embedded in the crystal surface formed by the substrate atoms 61 with insulating atoms 62, it is possible to form the atomic fine wires 63 completely buried from the surface, This further stabilizes the atomic thin wire 63. For example, as the atomic thin wire 63, gold (Au),
Metals such as silver (Ag), copper (Cu), cesium (Cs),
As the insulating atom 62, an insulator such as a metal oxide, a metal nitride, an organic carbon compound, or fullerene (C ₆₀ ) can be used. Further, the arrangement of the atomic thin wires 63 may have a zigzag structure, a multiple chain structure, or a random structure, and the insulating atoms 62 may have multiple layers. Fullerene (C ₆₀ ) can also be used as a conductor material by doping an alkali metal.

(Embodiment 5) This embodiment discloses an embodiment relating to a laminated atomic thin wire. FIG. 7A shows an atomic thin wire 74.
And (b) is a sectional view taken parallel to the atomic fine line 73 in AA ′. This is because the atomic fine line 73 formed on the substrate crystal 71 is covered with the insulating atom 72, and the atomic fine line 74 is further formed on the insulating atom 72.
5 is an example of a laminated atomic thin wire formed by coating with No. 5. The insulating atoms 72 and 75 may be the same type of atom or molecule. By repeating this, it is possible to obtain a laminated structure having an arbitrary number of layers, and it is also possible to arrange the device shown in Example 3 on each layer. At this time, the atomic thin wires between the layers must be separated at least to the extent that they do not interact with each other. According to a study by the inventors, the distance between the layers must be at least 1 nm or more,
In particular, it has been found that when the distance is 1.4 nm or more, good insulating properties are exhibited.

In the above embodiments, the atomic thin wires are formed in the grooves excluding the atoms constituting the substrate crystal, but the substrate does not necessarily have to be a crystal, and for example, silicon oxide (S
It may be amorphous, such as iO ₂ ). In this case, the atomic thin wire does not necessarily have a linear structure but may have an irregular structure.

In the above embodiments, the substrate crystal has been disclosed to have a structure of a single atom.
It is also possible to use a substrate composed of plural kinds of atoms such as aAs) and aluminum oxide (Al ₂ O ₃ ).

(Embodiment 6) This embodiment discloses an example in which, in the laminated atomic thin wires shown in Embodiment 5, a plurality of atomic thin wires formed in different layers are electrically connected. Figure 8
(A) is a sectional view parallel to the atomic thin wires 84 and 85, and (b) is a sectional view taken along line AA ′. Similar to the fifth embodiment, atomic thin wires 85 are formed on the crystal surface constituted by the substrate atoms 81, and the atomic thin wires 8 are covered with insulating atoms 82 and then the atomic thin wires 8 are formed.
In the laminated atomic thin wire formed by forming No. 4 and coating with the insulating atoms 83, the atomic thin wires 84 and 85 are electrically connected by the atomic thin wires 86. It is possible to obtain. The atoms constituting the atomic thin wires 84, 85, 86 may be the same type of atom, and the insulating atoms 82, 83 may be the same type of atom.

(Embodiment 7) In this embodiment, two layers in the same layer are used.
Disclosed is an example of the intersection of atomic lines in a book. 9A is a sectional view parallel to the atomic thin lines 95 and 96, and FIG. 9B is a sectional view taken along line AA ′. When the atomic thin wires 94 and 95 that intersect each other on the crystal surface formed by the substrate atoms 91 exist, the bridge structure is formed by the atomic thin wires 96 and 97 using the atomic thin wire connecting method between layers shown in the sixth embodiment. By doing so, it is possible to realize the crossing of the atomic thin wires without electrical interaction. The insulating atoms 92 and 93 may be the same type of atoms, and the atoms constituting the atomic thin wires 94, 95, 96 and 97 may be the same type of atoms.

[0021]

According to the atomic thin wire of the present invention, a circuit having a much higher density can be formed as compared with an integrated circuit using a conventional process.

[Brief description of drawings]

FIG. 1 (a) is a diagram of a buried atomic thin wire according to the present invention.
(B) A cross-sectional view of the atomic thin line at AA ′.

FIG. 2 is a diagram showing a procedure for producing atomic thin wires. (A1) (b
1) (c1) (d1) plan view. (A2) (b2) (c
2) (d2) (a1) (b1) (c1) (d
Sectional drawing in AA 'of 1).

3A and 3B are diagrams showing examples of atomic thin lines.

FIG. 4 is a diagram showing an example of an atomic thin line using a plurality of types of atoms.

FIG. 5 is a diagram showing an example of an atomic level switching element.

FIG. 6 is a view showing an example in which the surface of an atomic thin wire is covered.
(A) A top view. (B) A sectional view taken along line AA '.

FIG. 7 is a view showing an example of laminated atomic thin wires. (A) A top view. (B) A sectional view taken along line AA '.

FIG. 8 is a diagram showing an example in which atomic wires in different layers are connected. (A) Sectional drawing. (B) A sectional view taken along line AA '.

FIG. 9 is a diagram showing an example of intersection of atomic thin lines. (A) Sectional drawing. (B) A sectional view taken along line AA '.

[Explanation of symbols]

11, 25, 51, 63, 73, 74, 84, 85, 8
6, 94, 95, 96, 97; atomic thin wire, 12; substrate crystal, 21, 31, 41, 56, 61, 71, 81,
91; Substrate atom, 22; Atomic groove, 23; Adsorbed atom, 24, 32; Thin wire atom, 42; Thin wire atom 1,
43; thin-line atom 2, 52, 53; switching electrode,
54; switching atom, 55; guide atom, 6
2, 72, 75, 82, 83, 92, 93; insulating atom

Claims (3)

[Claims] 1. A plurality of conductive atoms can be embedded in a groove formed on an insulator or semiconductor crystal plane and having a depth and a width of one atom or a plurality of atoms to stably exist on the crystal plane. An atomic thin wire having a structure. 2. An atomic thin wire formed in a groove of an insulator or a semiconductor crystal, the surface of which is covered with a non-conductive atom so as to have a structure capable of stably existing inside the crystal. The atomic thin wire described in Item 1. 3. A layered structure formed by arranging a plurality of atomic thin wires on an insulator or semiconductor crystal plane in a direction perpendicular to the crystal surface, at a distance of not less than mutual interaction. The atomic thin wire described in Item 1.