JP2001053270A - Quantum arithmetic element and integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quantum arithmetic element of a structure, where electrons can be restrained in the vicinities of donor atomic nucleus, without having to put the electrons in a cryogenic state, and manufacturing of the element is made easy. SOLUTION: Silicon single-crystal fine grains 24 to 27 are arranged on a silicon substrate 21 at almost equal intervals via a silicon oxide film 22, and phosphorus atoms 32 to 35 are respectively contained in each of the fine grains 24 to 27 as a donor atom. In this way, by making small the radius of each of the fine grains 24 to 27 into a radius of 5 nm or thereabouts, the electrons ca be restrained in the vicinities of donor atomic nucleus, without putting the electrons in a cryogenic state. Moreover, as the position of each cell, which is constituted of each of the fine grains 24 to 27 is decided in a mechanical form, each of metallic electrodes 28 to 31 can be easily formed on each of the donor atoms 32 to 35 using a conventional photolithography technique and a self-matching technique. In turn, a quantum arithemetic element itself can be easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a quantum operation device that performs an operation by utilizing the interaction between an electron spin and a nuclear spin, and an integrated circuit equipped with the quantum operation device.

[0002]

2. Description of the Related Art In recent years, with the development of fine processing technology,
Mass production of semiconductor integrated circuits having a minimum processing line width of 50 nm to 180 nm has become possible. In the future, the generation of the fine processing technology will be updated every three to four years, and a development plan of a semiconductor integrated circuit having a minimum processing line width of about 30 nm has been made. At the experimental level, a minimum processing line width of about 10 nm is possible.

On the other hand, in the field of solid state physics, it is known that a so-called electron-nucleus double resonance phenomenon occurs between the nucleus of an impurity atom in a solid and an electron captured by the nucleus. I have.

Conventionally, as a solid-state device utilizing the above-described electron-nuclear double resonance phenomenon, a device having a device structure as shown in FIG. 8 is known (BEKane, “A silicon-based nuclear s”).
pinquantum computer ”Nature, vol.393, pp.133-137,
14May 1998.).

In FIG. 8, 1 is an A gate and 2 is a J gate.
Gate. Also, 3 and 5 are insulator layers
And 4 is a silicon single crystal layer. 6 is a support group
It is a board. The silicon atoms of the silicon single crystal layer 4 are atoms
Isotope with zero nuclear spin quantum number ²⁸Si,³⁰Consists only of Si
Has a nuclear spin quantum number of 1/2²⁹Si is excluded
Has been left.

A donor nucleus 7 is introduced into the silicon single crystal layer 4. The natural isotope of the phosphorus atom is 100% ³¹ P, and the nuclear spin quantum number is 1/2.
It is. Therefore, by using a phosphorus atom nucleus as the donor nucleus 7 introduced into the silicon single crystal layer 4, the nuclear spin can be measured. When the solid state device is placed at a sufficiently low temperature, free electrons are bound around the donor nucleus 7. 8
Indicates the probability density of a wave function of an electron bound to the donor nucleus 7 (a so-called electron cloud, hereinafter referred to as an electron cloud).

[0007] The phosphorus atoms serve as donors in silicon. The donor atom has five electrons, four of which
Individuals are contained in covalent bonds of the crystal and are diamagnetic,
The fifth electron is captured as a paramagnetic center with a spin S = 1/2. The donor electron wave function not only occupies the central donor atom, but also extends over hundreds of silicon atoms. The nuclear spin of silicon adds an extra fine structure. This phenomenon can be observed as double resonance (ENDOR) of electron spin and nuclear magnetism.

[0008] Under a static magnetic field B ₀ , the energy level of an ion is mainly determined by the Zeeman energy splitting of the electron level. That is, the electron spin quantum number _ms = ± 1 /
2 determines a high energy level and a low energy level. Hyperfine interactions cause the energy levels to break up more finely. That is, at the spin quantum number m _l = ± 1/2 of the nucleus, it is divided into a high energy level and a low energy level. There are two types of electron transitions, which have a nuclear spin quantum number m _l =
This corresponds to the case of − / and the case of m _l = + /. Assuming that the frequencies of the respective transitions are ω ₁ and ω ₂ , ω ₁ = γB ₀ −a / 2
(h / 2π), ω ₂ = γB ₀ + a / 2 (h / 2π). Note that ω
₁ is a transition between _ms = ± 1/2 when _ml = − /, and ω ₂ is a transition between _ms = ± 1/2 when _ml = + /. is there. Here, a is a hyperfine structure constant, γ is a constant, a gyromagnetic ratio, and h is a Planck constant.

In such a state, the sum of the nuclear spin angular momentum of the donor nucleus 7 and the electron spin angular momentum of the electron is stored in accordance with the angular momentum conservation law. Electron spin and nuclear spin have a correlation with each other by so-called hyperfine interaction (for example, Kittel, "Introduction to Solid State Physics (below)", Maruzen).

[0010] As is well known, spin is a physical quantity quantized into two states, and can have a quantum number of +1/2 and -1/2. As a result, when the solid-state device shown in FIG. 8 is placed in a constant static magnetic field, a difference in spin appears as a difference in resonance frequency. Therefore, when one of the information “0” and the information “1” is assigned to the spin quantum numbers “+＋ １” and “− /” of the phosphorus nucleus, the resonance frequency is measured. It is possible to know the contents of the information stored in the solid state device.

FIG. 9A shows a state in which the potential of the A gate 1 in the solid-state device shown in FIG. 8 is increased. The electron clouds 9a and 9b are drawn to the A gate 1 side. At this time, when the potential of one of the J gates 2a is further increased, as shown in FIG.
The ends of 10b will overlap each other under J-gate 2a. Incidentally, the potential of another J gate 2b is not raised. In this case, since the electron cloud 10a and the electron cloud 10b overlap to form one electron cloud 11, the electrons originally bound individually to the electron cloud 9a and the electron cloud 9b are replaced by a newly formed electron cloud. That is, it exists somewhere in one electron cloud 11.

As described above, in the solid-state device shown in FIG. 8, the spin state of a certain donor nucleus 7b can be successively transmitted to the adjacent donor nuclei 7a by manipulating the potential of the J gate 2. . Therefore, by giving an appropriate operation procedure, it is possible to perform a desired arithmetic operation.

[0013]

However, the above-mentioned conventional solid-state device has the following problems. That is, first, in the above-described solid-state device, a desired operation is performed by controlling the potentials of the A gate 1 located immediately above the donor nucleus 7 and the J gate 2 located in the middle between the adjacent donor nuclei 7 and 7. The operation is performed. Therefore, when the A gate 1 is formed, it is necessary to form the A gate 1 above the donor atoms introduced by so-called delta doping during the epitaxial growth of the silicon single crystal layer 4. Then, the position of the introduced donor atom is detected. However, since the position of the donor atom cannot be detected by observation from the surface, there is a problem that the formation of the A gate 1 is difficult. As a result, there is a problem that it is difficult to form the solid-state device.

Second, in the above-described solid-state device, in order for electrons to be bound in the vicinity of the donor nucleus 7, it is necessary to set the cryogenic temperature to almost zero degree, which poses a practical problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an easily manufactured quantum operation device capable of binding electrons to the vicinity of a donor nucleus without making the temperature extremely low, and an integrated circuit equipped with the quantum operation device. .

[0016]

In order to achieve the above object, a quantum operation device according to a first aspect of the present invention comprises a first insulating film formed on a substrate and a single silicon film disposed on the first insulating film. Crystal fine particles; a second insulating film formed on the first insulating film with the silicon single crystal fine particles interposed therebetween;
A metal electrode formed at least at the position of the silicon single crystal fine particles on the insulating film is provided, and the silicon single crystal fine particles contain a phosphorus atom as an impurity.

According to the above configuration, one of the information “0” and “1” is held as the spin quantum number of the phosphorus nucleus in the silicon single crystal fine particles. Then, the held information is read out by measuring the spin quantum number. At this time, when a potential is applied to the metal electrode to draw the electron cloud of phosphorus atoms toward the metal electrode, the resonance frequency changes. By doing so, the spin quantum number can be selectively measured.

At this time, phosphorus atoms as donor atoms are contained in the silicon single crystal fine particles, and the donor electrons are bound by a potential well formed by the silicon single crystal fine particles. Therefore, the electrons are bound to the vicinity of the donor nucleus without being brought to a very low temperature state, and are used without any practical problem.

Further, the silicon single crystal fine particles constitute a cell of a quantum operation device, and the position of the cell is determined by a mechanical shape. Therefore, even if there are a plurality of the above cells, the metal electrode can be easily and accurately formed on each donor atom by using the conventional photolithography technology or the self-alignment technology.

A quantum operation device according to a second aspect of the present invention comprises a first insulating film formed on a substrate and a plurality of silicon single crystal fine particles arranged on the first insulating film connected to each other. A silicon single crystal fine particle row, a second insulating film formed on the first insulating film with the silicon single crystal fine particle row interposed therebetween, and at least a position of the silicon single crystal fine particle row on the second insulating film. The semiconductor device is characterized in that the silicon single crystal fine particles include a phosphorus atom as an impurity with the formed metal film.

According to the above configuration, the plurality of silicon single crystal fine particles are connected to each other to form one silicon single crystal fine particle row. Therefore, when a potential is applied to the metal film, the electron cloud of phosphorus is attracted to the metal film side and separated into each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row. On the other hand, when no potential is applied to the metal film, the electron cloud of phosphorus spreads throughout the silicon single crystal fine particle row. Therefore, by controlling the potential of the metal film, it is possible to exchange nuclear spins between a plurality of phosphorus atoms using electrons as a medium.

Further, as in the case of the first aspect,
Electrons are bound to the vicinity of the donor nucleus without a cryogenic state, and can be used without any practical problems. In addition, since the position of each cell made of each of the silicon single crystal fine particles is determined by a mechanical shape, a metal film is easily formed on each donor atom using a conventional photolithography technique or a self-alignment technique.

In the quantum operation device according to the first or second aspect of the present invention, the silicon single crystal fine particles may be treated with an isotope ²⁸ S
It is desirable to be composed of silicon atoms of i and ³⁰ Si isotope.

According to the above configuration, the silicon atoms of the silicon single crystal fine particles are composed of only the isotopes ²⁸ Si and ³⁰ Si having a nuclear spin quantum number of 0, and the isotopes having a nuclear spin quantum number of 1/2. ²⁹ Si is not included. Therefore, the difference in the nuclear spin of the phosphorus atom, in which the natural isotope has ³¹ P of 100% and the nuclear spin quantum number is /, can be easily detected.

Further, in the quantum operation device according to the first or second invention, the diameter of each of the silicon single crystal fine particles is 10
It is desirable to set it to nm or less.

According to the above configuration, the diameter of each silicon single crystal fine particle is 10 nm or less. Therefore, if phosphorus atoms as impurities are mixed at an appropriate low concentration, the phosphorus atoms as the donor atoms will It can be considered that only about one silicon single crystal fine particle is contained. Therefore, one nuclear spin can be independently manipulated, and a quantum mechanical superposition state can be used. (If a plurality of donor nuclei are present in one silicon single crystal fine particle, the average You can only operate as a value).

The quantum operation device according to the second aspect of the present invention includes:
It is desirable to form a plurality of the metal films corresponding to each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row.

According to the above configuration, the spin state of a certain phosphorus nucleus is changed by controlling the potential of a plurality of metal films formed corresponding to each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row. It is successively transferred to the adjacent phosphorus nuclei. Therefore, a desired calculation operation is performed by giving an appropriate operation procedure.

The integrated circuit according to a third aspect of the present invention is the integrated circuit according to the first aspect.
Alternatively, an integrated circuit chip on which the quantum operation device of the second invention is mounted is sandwiched between magnetic chips.

According to the above configuration, the static magnetic field can be continuously applied to the entire quantum operation element on the integrated circuit chip by the magnetic chip without providing any special magnetic field applying means. Therefore, it becomes possible to operate the nuclear spin by utilizing the contact hyperfine interaction by the integrated circuit alone.

According to a fourth aspect of the present invention, there is provided an integrated circuit device comprising a circuit board on which an integrated circuit chip on which the quantum operation element of the first or second aspect is formed is sandwiched by a magnetic material. Features.

According to the above configuration, a static magnetic field can be continuously applied to the entire quantum operation element on the integrated circuit chip by the magnetic material without providing any special magnetic field applying means. Therefore, it becomes possible to operate the nuclear spin by utilizing the contact hyperfine interaction in the integrated circuit device alone.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

<First Embodiment> FIG. 1 is a schematic sectional view of a quantum operation device according to the present embodiment. On a first silicon oxide film 22 formed on the surface of a silicon substrate 21, silicon single crystal fine particles 24 to 27 are arranged at substantially equal intervals. Further, on the first silicon oxide film 22,
A second silicon oxide film 23 is formed with silicon single crystal fine particles 24 to 27 interposed therebetween. Metal electrodes 28 to 31 corresponding to the positions of silicon single crystal fine particles 24 to 27 are formed on second silicon oxide film 23. Are formed.

The silicon single crystal fine particles 24 to 27 contain phosphorus atoms 32 to 35 as donor atoms, and the electron clouds of the phosphorus atoms 32 to 35 are formed in the respective silicon single crystal fine particles 24 to 27. Spread throughout. Therefore, although the electrons detached from the phosphorus atoms 32 to 35 are free electrons, they are spatially confined in the silicon single crystal fine particles 24 to 27, and only in the vicinity of the phosphorus atoms 32 to 35 like the bound electrons. Cannot exist.

The silicon single crystal fine particles 24 to 27 can be formed by a method disclosed in, for example, JP-A-11-97667. The metal electrodes 28 to 31 can be formed by photolithography in the same manner as in a normal integrated circuit. Alternatively, the literature `` Inoue, et.al., Appl.Phys.Lett., Vol. 73, No. 14, pp. 19
76-1978, 1998, an organic molecular film is formed in a self-aligned manner on silicon single crystal fine particles 24 to 27 by using the method of forming an organic molecular film disclosed in May be implemented. In particular, the latter method is effective when the distance between the silicon single crystal fine particles 24 to 27 is narrowed.

As described above, according to the present embodiment, each of the silicon single crystal fine particles 24 to 27 constitutes a basic structure (cell) of the quantum operation element. Therefore, the position of the cell is determined by the mechanical shape, and it is not necessary to detect the positions of the phosphorus atoms 32 to 35 when forming the metal electrodes 28 to 31 as in the case of forming the conventional solid-state device shown in FIG. In addition, it becomes very easy to create a quantum operation device.

The quantum operation device according to the present embodiment utilizes contact hyperfine interaction (contact hyperfine interaction) between donor nuclei and electrons, similarly to the conventional solid-state device shown in FIG. For this purpose, the silicon contained in the silicon single crystal particles 24 to 27, must be composed only of the isotope ²⁸ Si and ³⁰ Si.

First, the interaction of the contact ultrafine structure with respect to one silicon single crystal fine particle 24 in FIG. 1 will be described. Considering the polar coordinates whose origin is the position of the nucleus of the donor atom (phosphorus atom) 32, the electron wave function can be expressed as a function ψ (r). Here, r is the distance from the origin. The intensity of the contact hyperfine interaction energy between the donor nucleus and the electron is r = 0
Electronic existence probability in | ψ (0) | proportional to ^2. Therefore, to increase the contact hyperfine structure interaction energy, the electron existence probability | ψ (0) | ² must be increased.

In a bulk silicon single crystal, electrons at room temperature are free electrons, and the existence probability | ψ (0) | ² is practically zero. In this case, if the entire device is kept at an extremely low temperature as in the conventional solid-state device shown in FIG. 8, electrons can be bound to donor nuclei, and a sufficiently large existence probability | ψ (0) | ² can be obtained. Can be. Typically, T is kept at about 100 mK in absolute temperature. At this temperature, the electrons are bound to the lowest energy level (s state). By the way, this binding force is weak, and the excitation energy to the first excitation level is about 15 meV, which is about 174 K in terms of temperature.

In the present embodiment, due to its structure, electrons are confined inside silicon single crystal fine particles 24. As a result, the electrons are bound by the potential well formed by the silicon single crystal fine particles 24 without keeping the entire device at an extremely low temperature. The wave function of an electron bound in a particle having a radius a becomes the ground state when the quantum size effect occurs because the radius a is sufficiently small.
The wave function in the (s state) is represented by ψ (r) = Nj ₀ (r / a) (1). Here, j ₀ is a zero-order spherical Bessel function j ₀ (x) = sin (x) (1 / x) (2), and has a maximum at x = 0. As a result, the existence probability of the electron at r = 0 is | ψ (0) | ² ∝a ^−3. Therefore, in the present embodiment, the existence probability | ψ (0) is obtained by sufficiently reducing the radius a of the fine particles. | ² can be increased.

The energy difference ΔE between the first excitation level and the ground level in the s state is about 130 meV when the radius is 5 nm as a typical element size.
Converted to absolute temperature, it becomes 1508K. That is, the binding force of electrons can be increased by sufficiently reducing the radius a of the fine particles. Here, the mass is m = (m where m _{eo is} the rest mass of the electron, m _{t is} the transverse mass, and m _eff is the effective mass.
_eff · m _t ²⁾ using a ^1/3 = ^0.3216m _eo, analytically determined from the radius vector equation of equation Schrodinger with V ₀ = 3.15 eV as depth of the potential barrier at r = a Was.

The quantum operation device according to the present embodiment is constituted by providing cells including silicon single crystal fine particles 24 to 27 exhibiting such contact ultrafine structure interaction. Therefore, the contact ultrafine structure interaction can be stably generated in each cell.

Here, the quantum operation device according to the present embodiment is arranged such that “0,
It functions as a memory that holds the information of "1" as the spin quantum number of the phosphorus nucleus. Then, for example, when reading information held in the silicon single crystal fine particles 24,
By applying a potential to the metal electrodes 29 to 31, the electron clouds in the silicon single crystal fine particles 25 to 27 are drawn toward the metal electrodes 29 to 31 as illustrated in FIG. Then, by measuring the resonance frequency in that state, the retained information can be read out by the silicon single crystal fine particles 24 alone.

As described above, in the quantum operation device according to the present embodiment, silicon single crystal fine particles 24 to 27 are arranged on silicon substrate 21 via silicon oxide film 22 at substantially equal intervals. The silicon single crystal fine particles 24 to 27 include phosphorus atoms 32 to 3 as donor atoms.
5, and the electron clouds of the respective phosphorus atoms 32 to 35 are spread throughout the respective silicon single crystal fine particles 24 to 27. Therefore, each silicon single crystal fine particle 24 to 27
By reducing the radius to about 5 nm, the contact ultrafine structure interaction causes the first
The energy difference ΔE between the excitation level and the ground level is ΔE = 13
It can be set to about 0 meV, and the electrons can be more stably kept at the ground level state than in a bulk silicon single crystal.

That is, according to the present embodiment, electrons can be bound to the vicinity of the donor nucleus without being brought to a very low temperature state, and can be used without practical problems.

In the quantum operation device according to the present embodiment, each of the silicon single crystal fine particles 24 to 27 constitutes a cell of the quantum operation device. The position of each cell is determined by the mechanical shape. Therefore, each of the metal electrodes 28 to 31 can be easily formed on each of the donor atoms 32 to 35 by using a conventional photolithography technique or a self-alignment technique.

<Second Embodiment> FIG. 2 is a schematic sectional view of a quantum operation device according to the present embodiment. On a first silicon oxide film 42 formed on the surface of a silicon substrate 41, a row of silicon single crystal fine particles 44 is formed. This row of silicon single crystal fine particles 44 is used to grow the plurality of silicon single crystal fine particles at substantially equal intervals in the same manner as in the first embodiment, so that the individual silicon single crystal fine particles contact each other. It is formed by growing. A second silicon oxide film 43 is formed on the first silicon oxide film 42 with a silicon single crystal fine particle row 44 interposed therebetween, and the position of the silicon single crystal fine particle row 44 is formed on the second silicon oxide film 43. A metal electrode film 45 is formed corresponding to.

The silicon single crystal fine particle row 44
In the individual silicon single crystal fine particles constituting the above, phosphorus atoms 46 to 50 are contained as donor atoms. In the case of this quantum operation device, the radius of the silicon single crystal fine particles is set to 5
When the potential is not applied to the metal electrode film 45 by reducing the diameter to about nm, as shown in FIG. 2B, the electron clouds of the phosphorus atoms 46 to 50 Has spread.

FIG. 3 shows only the portion of the silicon single crystal fine particle row 44 in FIG. FIG. 3A shows a state of an electron cloud when a potential is applied to the metal electrode film 45. FIG. 3B shows the state of an electron cloud when no potential is applied to the metal electrode film 45 (corresponding to FIG. 2B).

As shown in FIG. 3A, the metal electrode film 4
5, when the potential is applied to the metal electrode film 4,
The electron cloud 51 is separated by the convex portion 44 a at the boundary between the silicon single crystal fine particles constituting the silicon single crystal fine particle row 44. In that case, the metal electrode film 45
The silicon single crystal fine particle rows 44 are uniformly formed on all the silicon single crystal fine particles. Therefore, the electron cloud 51 is evenly distributed to the locations of all the silicon single crystal fine particles. On the other hand, as shown in FIG. 3B, when no potential is applied to the metal electrode film 45, the electron cloud 52 spreads throughout the silicon single crystal fine particle row 44.

Therefore, if a plurality of the metal electrode films 45 are formed corresponding to each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row 44 as in the first embodiment, the potential of each metal electrode is increased. Can be independently operated to adjust the magnitude of the exchange interaction between the nuclear spins in the adjacent silicon single crystal fine particles by forming the silicon single crystal fine particle row 44. That is, for example, the spin state of the nucleus of the donor atom (phosphorus atom) 46 can be transmitted to the nucleus of the adjacent donor atom 47. Therefore, a desired calculation operation can be performed by giving an appropriate potential operation procedure.

In this case, it is sufficient to use only metal electrodes corresponding to the conventional A gate 1 shown in FIG. 8 as control electrodes. Therefore, a control electrode corresponding to the conventional J gate 2 becomes unnecessary.

In the quantum operation device shown in FIG. 2, the metal electrode film 45 is uniformly formed on all the silicon single crystal fine particles constituting the silicon single crystal fine particle row 44. However, in the present invention, the positional relationship between the metal electrode film and the row of silicon single crystal fine particles does not need to be in the positional relationship as shown in FIG. 2, and there is no particular problem even in the positional relationship as in FIG. . In this case, it is possible to use a growth condition under which the silicon single crystal fine particles are sufficiently in contact with each other during the growth of the silicon single crystal fine particles. Incidentally, 61 is a silicon substrate, 62 and 63 are silicon oxide films, 64 is a row of silicon single crystal fine particles, 65 is a metal electrode film, and 66 is a donor atom (phosphorus atom).

Further, as shown in FIG.
May be formed so as to partially cover the silicon single crystal fine particle row 72. In this case, when growing the silicon single crystal fine particles, it is possible to use a growth condition in which the number of growth nuclei of the silicon single crystal fine particles is large. Further, as shown in FIG. 6, one metal electrode film 75 may be formed so as to cover the entire plurality of silicon single crystal fine particle rows 76, 77. In this case, when growing the silicon single crystal fine particles, it is possible to use a growth condition in which the number of growth nuclei of the silicon single crystal fine particles is small.

In the first and second embodiments, the diameter of each silicon single crystal fine particle is 10 nm.
In the case of forming below, if phosphorus atoms as impurity atoms are mixed at an appropriate low concentration, approximately one phosphorus atom as the donor atom is contained in each silicon single crystal fine particle. Can be considered. Therefore, in that case, one nuclear spin can be independently manipulated, and a quantum mechanical superposition state can be used.

On the other hand, when the diameter of each silicon single crystal fine particle is formed to be larger than 10 nm, it is necessary to make the silicon single crystal fine particles contain only one phosphorus atom. Phosphorus atoms, which are impurity atoms, must be mixed at an extremely low concentration, making concentration control difficult. Therefore, a plurality of donor nuclei exist in one silicon single crystal fine particle, and an operation as an average value is performed.

<Third Embodiment> FIG. 7 is a bird's-eye view in the present embodiment. In the quantum operation device according to the first and second embodiments, when operating the nuclear spin using the contact hyperfine interaction, it is necessary to continuously apply a static magnetic field to the entire device.

Therefore, in the present embodiment, the first,
As in the second embodiment, an integrated circuit chip 81 on which a quantum operation element is formed using a normal integrated circuit technique is sandwiched between magnetic chips 82 and 83 and bonded. By doing so, a static magnetic field can be stably applied to the quantum operation element built in the integrated circuit chip 81.

In the case where only the integrated circuit chip on which the quantum operation device according to the first and second embodiments is formed is mounted on the circuit board, the entire circuit board is bonded with a magnetic material therebetween. May be.

[0061]

As is clear from the above, in the quantum operation device of the first invention, silicon single crystal fine particles are arranged on a first insulating film formed on a substrate, and the silicon single crystal fine particles are sandwiched between the silicon single crystal fine particles. A metal electrode is formed at least at the position of the silicon single crystal fine particles on the second insulating film, and the silicon single crystal fine particles contain a phosphorus atom as an impurity. Phosphorus electrons as atoms are bound by potential wells formed by the silicon single crystal fine particles. Therefore, the electrons can be bound to the vicinity of the donor nucleus without being brought to a very low temperature state, and can be used without practical problems.

Further, the silicon single crystal fine particles constitute a cell of the present quantum operation device, and the position of the cell is determined by a mechanical shape. Therefore, the metal electrode can be easily and accurately formed on each donor atom by using a conventional photolithography technique or a self-alignment technique. As a result, the quantum operation device can be easily formed.

Further, if a potential is applied to the metal electrode,
The electron cloud of the phosphorus atoms in the silicon single crystal fine particles can be drawn to the metal electrode side. Therefore, by applying a potential to the metal electrode, the resonance frequency of the phosphorus nucleus can be modulated, and a logical operation, a read operation, and a write operation can be selectively performed on a cell at a desired position.

Further, in the quantum operation device according to the second aspect of the present invention, a row of silicon single crystal fine particles in which a plurality of silicon single crystal fine particles are connected to each other is arranged on a first insulating film formed on a substrate. A second insulating film is formed with the silicon single crystal fine particle row interposed therebetween, and a metal film is formed on at least the position of the silicon single crystal fine particle row on the second insulating film. As in the case of the first aspect, electrons can be bound to the vicinity of the donor nucleus without being brought to an extremely low temperature state, and can be used without practical problems. Further, since the position of each cell composed of the silicon single crystal fine particles is determined by the mechanical shape, the metal film can be easily formed on each donor atom by using a conventional photolithography technique or a self-alignment technique. . As a result, the quantum operation device can be easily formed.

Further, when a potential is applied to the metal film, the electron cloud of phosphorus is attracted to the metal film side and separated into each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row. On the other hand, when the potential is not applied to the metal film, the electron cloud of phosphorus spreads over the entire row of silicon single crystal fine particles. By controlling the potential of the metal film, electrons between a plurality of phosphorus atoms are removed. It is possible to exchange nuclear spins as a medium.

Further, in the quantum operation device according to the first or second aspect of the present invention, the silicon single crystal fine particles may be treated with an isotope ²⁸ S
If it is composed of silicon atoms of i and ³⁰ Si isotope, the silicon single crystal fine particles have a nuclear spin quantum number of 1/2.
Does not include the isotope ²⁹ Si. Therefore, the natural isotope has ³¹ P of 100% and a nuclear spin quantum number of 1
The difference in the nuclear spin of the phosphorus atom of / 2 can be easily detected.

Further, in the quantum operation device according to the first or second aspect, the diameter of each of the silicon single crystal fine particles may be 10
In the case where the diameter is set to be equal to or smaller than nm, it is possible to consider that only one donor atom is contained in each of the silicon single crystal fine particles if phosphorus atoms as impurity atoms are mixed at an appropriate low concentration. . Therefore, one nuclear spin can be independently manipulated, and the quantum mechanical superposition state can be used.

The quantum operation device according to the second aspect of the present invention comprises:
If a plurality of the metal films are formed corresponding to each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row, by controlling the potential of the plurality of metal films,
The spin state of a certain phosphorus nucleus can be transferred one after another to the adjacent phosphorus nuclei. Therefore, a desired operation can be performed by giving an appropriate operation procedure.

Further, the integrated circuit according to the third invention is characterized in that
Alternatively, since the integrated circuit chip on which the quantum operation element of the second invention is mounted is sandwiched between magnetic chips, the magnetic chip can be used without providing special magnetic field applying means and without requiring electric power. The static magnetic field can be stably applied to the entire quantum operation element on the integrated circuit chip. That is, according to the present invention, the present integrated circuit alone
It is possible to manipulate nuclear spins using contact hyperfine interaction.

In the integrated circuit device according to the fourth aspect of the present invention, the circuit board on which the integrated circuit chip on which the quantum operation element according to the first or second aspect of the invention is formed is sandwiched by magnetic materials. The static magnetic field can be stably applied to the entire quantum operation element on the integrated circuit chip by the magnetic material without providing a special magnetic field applying unit. Therefore, according to the present invention, it is possible to operate nuclear spins by utilizing the contact hyperfine interaction alone with the present integrated circuit device.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a quantum operation device of the present invention.

FIG. 2 is a schematic cross-sectional view of a quantum operation device different from FIG.

FIG. 3 is a diagram showing a state change of an electron cloud in FIG. 2;

FIG. 4 is a diagram showing a positional relationship between a metal electrode film different from FIG. 2 and a row of silicon single crystal fine particles.

FIG. 5 is a diagram showing a positional relationship between a metal electrode film and a row of silicon single crystal fine particles different from FIGS. 2 and 4;

FIG. 6 is a diagram showing a positional relationship between a metal electrode film and a row of silicon single crystal fine particles different from those of FIGS. 2, 4 and 5;

FIG. 7 is a diagram showing a circuit chip in which an integrated circuit chip on which the quantum operation device shown in FIGS.

FIG. 8 is a diagram showing the structure of a conventional solid-state device utilizing the electron-nuclear double resonance phenomenon.

9 is a diagram showing a state of an electron cloud when a potential is applied to the A gate and a potential is further applied to one J gate in FIG. 8;

[Explanation of symbols]

 21, 41, 61: silicon substrate, 22, 23, 42, 43, 62, 63: silicon oxide film, 24 to 27: silicon single crystal fine particles, 28 to 31: metal electrode, 32 to 35, 46 to 50, 66 ... donor atoms (phosphorus atoms), 44, 64, 72, 76, 77 ... silicon single crystal fine particle array, 45, 65, 71, 75 ... metal electrode film, 51, 52 ... electron cloud, 81 ... integrated circuit chip, 82 , 83 ... Magnetic chip.

Claims (10)

[Claims] A first insulating film formed on a substrate; silicon single crystal fine particles disposed on the first insulating film; and a silicon single crystal fine particle formed on the first insulating film with the silicon single crystal fine particles interposed therebetween. And a metal electrode formed at least at the position of the silicon single crystal fine particles on the second insulating film, wherein the silicon single crystal fine particles contain a phosphorus atom as an impurity. The quantum operation element characterized by the above-mentioned. A first insulating film formed on the substrate; a row of silicon single crystal fine particles formed by connecting a plurality of silicon single crystal fine particles arranged on the first insulating film to each other; A second insulating film formed on the film with the silicon single crystal fine particle row interposed therebetween, and a metal film formed at least at the position of the silicon single crystal fine particle row on the second insulating film; A quantum operation device comprising silicon single crystal fine particles containing phosphorus atoms as impurities. 3. The quantum operation device according to claim 1, wherein the silicon atoms constituting the silicon single crystal fine particles are composed of an isotope ²⁸ Si and an isotope ³⁰ Si. Quantum operation device. 4. The quantum operation device according to claim 3, wherein each silicon single crystal fine particle has a diameter of 10 nm or less. 5. The quantum operation device according to claim 2, wherein a plurality of the metal films are formed corresponding to each of the silicon single crystal fine particles constituting the silicon single crystal fine particle row. Quantum operation device. 6. The quantum operation device according to claim 2, wherein the metal film is formed so as to cover the entire row of the silicon single crystal fine particles. 7. The quantum operation device according to claim 6, wherein a plurality of rows of silicon single crystal fine particles covered with the metal film are provided. 8. The quantum operation device according to claim 2, wherein the metal film is formed so as to cover a part of the silicon single crystal fine particle row. 9. An integrated circuit, comprising an integrated circuit chip on which the quantum operation element according to claim 1 is mounted, sandwiched between magnetic chips. 10. An integrated circuit comprising: a circuit board on which an integrated circuit chip on which the quantum operation device according to claim 1 is formed is mounted by a magnetic material. Circuit device.