JP4445068B2 - Quantum arithmetic element and integrated circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a quantum operation element that performs an operation by utilizing an interaction between an electron spin and a nuclear spin, and an integrated circuit on which the quantum operation element is mounted.
[0002]
[Prior art]
  In recent years, with the progress of microfabrication technology, mass production of semiconductor integrated circuits having a minimum processing line width of 250 nm to 180 nm has become possible. The microfabrication technology will continue to be updated every three to four years, and development plans for semiconductor integrated circuits having a minimum processing line width of about 30 nm have been made. At the experimental level, a minimum processing line width of about 10 nm is possible.
[0003]
  On the other hand, in the field of solid state physics, it is known that a so-called electron-nuclear double resonance phenomenon occurs between a nucleus of an impurity atom in a solid and an electron captured by the nucleus.
[0004]
  Conventionally, as a solid-state device utilizing the above-described electron-nuclear double resonance phenomenon, one having an element structure shown in FIG. 8 is known (BEKane, “A silicon-based nuclear spin quantum computer” Nature, vol. 393, pp.133-137, 14 May 1998.).
[0005]
  In FIG. 8, 1 is a gate called A gate, and 2 is a gate called J gate. Reference numerals 3 and 5 denote insulator layers, and reference numeral 4 denotes a silicon single crystal layer. Reference numeral 6 denotes a support substrate. Silicon atoms in the silicon single crystal layer 4 are isotopes having a nuclear spin quantum number of 0²⁸Si,³⁰An isotope consisting only of Si and having a nuclear spin quantum number of 1/2²⁹Si has been removed.
[0006]
  Further, donor nuclei 7 are introduced into the silicon single crystal layer 4. The natural isotope of the phosphorus atom³¹P is 100% and the nuclear spin quantum number is 1/2. 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 this solid-state device is placed at a sufficiently low temperature, free electrons are bound around the donor nucleus 7. Reference numeral 8 denotes a probability density of a wave function of electrons bound to the donor nucleus 7 (a so-called electron cloud, which will be referred to as an electron cloud hereinafter).
[0007]
  The phosphorus atom becomes a donor in silicon. There are 5 electrons in the donor atom, 4 of which are included in the covalent bond of the crystal and become diamagnetic, but the 5th electron is a paramagnetic center with spin S = 1/2. Have been caught. The wave function of the donor electron not only occupies the central donor atom, but extends over several hundred silicon atoms. The nuclear spin of silicon further adds hyperfine structure. This phenomenon can be observed as an electron spin and nuclear magnetic double resonance (ENDOR).
[0008]
  Static magnetic field B₀Under, the energy level of an ion is mainly determined by the Zeeman energy splitting of the electron level. In other words, electron spin quantum number m_s= ± 1/2 determines the high energy level and the low energy level. Hyperfine interactions break up energy levels more finely. In other words, nuclear spin quantum number m_l= ± 1/2, it can be divided into a high energy level and a low energy level. There are two types of electron transitions, and they have a nuclear spin quantum number of m_l= M with case of -1/2_lThis corresponds to the case of = + 1/2. Let ω be the frequency of each transition₁, ω₂Then ω₁= ΓB₀-A / 2 (h / 2π), ω₂= ΓB₀+ A / 2 (h / 2π). Ω₁Is m_l= M for -1/2_s= Transition between ± 1/2 and ω₂Is m_l= M when +1/2_s= Transition between ± 1/2. Here, a is a hyperfine structure constant, γ is a constant and a gyromagnetic ratio, and h is a Planck's constant.
[0009]
  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 electrons is preserved according to the law of conservation of angular momentum. The electron spin and the nuclear spin have a correlation with each other by so-called hyperfine interaction (for example, “Introduction to Solid State Physics (below)” by Maruzen).
[0010]
  As is well known, a spin is a physical quantity quantized into two states, and can have quantum numbers 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 either the information “0” or the information “1” is assigned to the spin quantum numbers “+1/2” and “−1/2” of the phosphorus nucleus, The contents of the information stored in the solid state element can be known.
[0011]
  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 attracted 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. 9B, the end portions of the two electron clouds 10a and 10b overlap each other under the J gate 2a. Note that the potential of the other J gate 2b is not increased. In this case, since the electron cloud 10a and the electron cloud 10b overlap each other to form one electron cloud 11, the electrons originally restrained individually by the electron cloud 9a and the electron cloud 9b are newly created. One electron cloud 11 exists somewhere.
[0012]
  As described above, in the solid-state device shown in FIG. 8, by manipulating the potential of the J gate 2, the spin state of a certain donor nucleus 7b can be successively transmitted to the adjacent donor nucleus 7a. Therefore, it is possible to perform a desired calculation operation by giving an appropriate operation procedure.
[0013]
[Problems to be solved by the invention]
  However, the conventional solid element has the following problems. That is, first, in the solid-state device, a desired calculation is performed by controlling the potential between the A gate 1 positioned immediately above the donor nucleus 7 and the J gate 2 positioned between the adjacent donor nuclei 7 and 7. The operation is performed. Therefore, when forming the A gate 1, it is necessary to form it on the upper part of the donor atom introduced by using a so-called delta doping method during the epitaxial growth of the silicon single crystal layer 4. Therefore, although the position of the introduced donor atom is detected, there is a problem that it is difficult to form the A gate 1 because the position of the donor atom cannot be detected by observation from the surface. As a result, there is a problem that it is difficult to form the solid element.
[0014]
  Secondly, in the solid state device, in order for electrons to be bound in the vicinity of the donor nucleus 7, it is necessary to make the temperature extremely low near 0 degrees, which is problematic in practice.
[0015]
  SUMMARY OF THE INVENTION An object of the present invention is to provide a quantum arithmetic element that can easily bind electrons to the vicinity of a donor nucleus without making the temperature extremely low, and an integrated circuit equipped with the quantum arithmetic element.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, the quantum arithmetic element of the first invention is
  A first insulating film formed on the substrate;
  Silicon single crystal fine particles disposed on the first insulating film;
  A second insulating film formed on the first insulating film with the silicon single crystal fine particles interposed therebetween;
  A metal electrode formed on at least the position of the silicon single crystal fine particles on the second insulating film;
  In the silicon single crystal fine particles,As an impurityThe concentration of the silicon single crystal fine particles can be regarded as containing only one atom.Contains phosphorus atoms
It is characterized by that.
[0017]
  According to the above configuration, either information “0” or “1” is held as the spin quantum number of the phosphorus nucleus in the silicon single crystal fine particles. The retained information is read by measuring the spin quantum number. At that time, if a potential is applied to the metal electrode to draw an electron cloud of phosphorus atoms toward the metal electrode, the resonance frequency changes. By doing so, the spin quantum number can be selectively measured.
[0018]
  At that time, phosphorus atoms as donor atoms are contained in the silicon single crystal fine particles.At a concentration that can be considered to contain only one atomThe donor electrons are constrained by the potential well formed by the silicon single crystal fine particles. For this reason, electrons are constrained in the vicinity of the donor nucleus without being brought into a cryogenic state, and can be used without any problem in practice.
[0019]
  Furthermore, the silicon single crystal fine particles constitute a cell of a quantum arithmetic element, and the position of the cell is determined by the mechanical shape. Therefore, even if there are a plurality of the cells, the metal electrode can be easily and accurately formed on each donor atom by using the conventional photolithography technique or self-alignment technique.
[0020]
  The quantum arithmetic element of the second invention is
  A first insulating film formed on the substrate;
  A single-crystal silicon particle array in which a plurality of single-crystal silicon particles arranged on the first insulating film are connected to each other;
  A second insulating film formed on the first insulating film with the silicon single crystal fine particle rows interposed therebetween;
  A metal film formed on at least the position of the silicon single crystal fine particle row on the second insulating film;
  In each of the above silicon single crystal fine particles,As an impurityThe concentration of the silicon single crystal fine particles can be regarded as containing only one atom.Contains phosphorus atoms
It is characterized by that.
[0021]
  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 an electric 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 particles constituting the silicon single crystal particle array. On the other hand, when no potential is applied to the metal film, the electron cloud of phosphorus spreads throughout the silicon single crystal particle array. Therefore, by controlling the potential of the metal film, it becomes possible to exchange nuclear spins using electrons as a medium between a plurality of phosphorus atoms.
[0022]
  Further, as in the case of the first invention, electrons are constrained in the vicinity of the donor nucleus without being brought to a cryogenic state, and can be used without any problem in practice. In addition, since the position of each cell composed of each of the silicon single crystal fine particles is determined by the mechanical shape, a metal film can be easily formed on each donor atom using a conventional photolithography technique or self-alignment technique.
[0023]
  The quantum arithmetic element according to the first or second aspect of the present invention is the isotopic isotope of the silicon single crystal fine particles.²⁸Si and isotopes³⁰It is desirable to use Si silicon atoms.
[0024]
  According to the above configuration, the silicon atom of the silicon single crystal fine particle is an isotope having a nuclear spin quantum number of 0.²⁸Si,³⁰An isotope consisting only of Si and having a nuclear spin quantum number of 1/2²⁹Si is not included. Therefore, natural isotopes³¹A difference in the nuclear spin of a phosphorus atom having P of 100% and a nuclear spin quantum number of 1/2 is easily detected.
[0025]
  In the quantum arithmetic element according to the first or second invention, it is desirable that the diameter of each silicon single crystal fine particle is 10 nm or less.
[0026]
  According to the above configuration, since the diameter of each silicon single crystal fine particle is 10 nm or less, if phosphorus atoms as impurities are mixed at an appropriate low concentration, the phosphorus atoms as the donor atoms are converted into the silicon single crystals. It can be considered that only one crystal fine particle is contained. Therefore, one nuclear spin can be manipulated independently and the quantum mechanical superposition state can be used (if there are multiple donor nuclei in one silicon single crystal fine particle, the average Can only be manipulated as a value).
[0027]
  In the quantum arithmetic element according to the second aspect of the present invention, 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 array.
[0028]
  According to the above configuration, the spin states of certain phosphorus nuclei are successively adjacent to each other by manipulating the potential of the plurality of metal films formed corresponding to each of the silicon single crystal particles constituting the silicon single crystal particle array. It is transmitted to the matching phosphorus nucleus. Therefore, a desired calculation operation is performed by giving an appropriate operation procedure.
[0029]
  An integrated circuit according to a third aspect of the invention is characterized in that an integrated circuit chip on which the quantum arithmetic element according to the first or second aspect of the invention is mounted is sandwiched between magnetic chips.
[0030]
  According to the above configuration, a static magnetic field can be continuously applied to the entire quantum arithmetic element on the integrated circuit chip by the magnetic chip without providing any special magnetic field applying means. Therefore, it becomes possible to manipulate the nuclear spin using the contact hyperfine interaction with this integrated circuit alone.
[0031]
  An integrated circuit device according to a fourth aspect of the invention is a circuit on which an integrated circuit chip on which the quantum arithmetic element of the first or second aspect of the invention is formed is mountedsubstrateIs characterized by being sandwiched between magnetic materials.
[0032]
  According to the above configuration, a static magnetic field can be continuously applied to the entire quantum arithmetic element on the integrated circuit chip by the magnetic body without providing a special magnetic field applying unit. Therefore, the nuclear spin can be manipulated by using the contact hyperfine interaction with the integrated circuit device alone.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0034]
  <First embodiment>
  FIG. 1 is a schematic cross-sectional view of the quantum arithmetic element according to the present embodiment. On the first silicon oxide film 22 formed on the surface of the silicon substrate 21, silicon single crystal fine particles 24 to 27 are arranged at substantially equal intervals. Further, a second silicon oxide film 23 is formed on the first silicon oxide film 22 with the silicon single crystal fine particles 24 to 27 interposed therebetween. On the second silicon oxide film 23, the silicon single crystal fine particles 24 to 27 are formed. Corresponding to the position 27, metal electrodes 28 to 31 are formed.
[0035]
  The silicon single crystal fine particles 24-27 contain phosphorus atoms 32-35 as donor atoms, and the electron clouds of the respective phosphorus atoms 32-35 spread throughout the silicon single crystal fine particles 24-27. ing. Therefore, although the electrons separated 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 are only in the vicinity of the phosphorus atoms 32 to 35 like the bound electrons. Cannot exist.
[0036]
  As a method for forming the silicon single crystal fine particles 24 to 27, for example, a method as disclosed in JP-A-11-97667 can be used. Further, the metal electrodes 28 to 31 can be formed by photolithography in the same manner as a normal integrated circuit. Alternatively, using the method for forming an organic molecular film disclosed in the literature “Inoue, et.al., Appl. Phys. Lett., Vol. 73, No. 14, pp. 1976-1978, 1998” An organic molecular film may be formed on the silicon single crystal fine particles 24 to 27 in a self-aligning manner to form the metal electrodes 28 to 31. In particular, the latter method is effective when the interval between the silicon single crystal fine particles 24 to 27 is narrowed.
[0037]
  Thus, according to the present embodiment, each of the silicon single crystal fine particles 24 to 27 constitutes the 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 formation of the conventional solid element shown in FIG. Therefore, it becomes very easy to create a quantum operation element.
[0038]
  As in the conventional solid state device shown in FIG. 8, the quantum arithmetic element in the present embodiment utilizes contact hyperfine structure interaction (contact hyperfine interaction) between donor nuclei and electrons. For this purpose, silicon constituting the silicon single crystal fine particles 24 to 27 is an isotope.²⁸Si and³⁰It must consist only of Si.
[0039]
  First, the contact hyperfine structure interaction will be described with respect to one silicon single crystal fine particle 24 in FIG. Considering polar coordinates whose origin is the position of the nucleus of the donor atom (phosphorus atom) 32, the wave function of electrons can be expressed as a function ψ (r). Here, r is the distance from the origin. The strength of the contact hyperfine interaction energy between the donor nucleus and the electron is the electron existence probability at r = 0 | ψ (0) |²Is proportional to Therefore, in order to increase the contact hyperfine structure interaction energy, the existence probability of electrons | ψ (0) |²Must be increased.
[0040]
  In bulk silicon single crystals, electrons at room temperature are free electrons, and the existence probability | ψ (0) |²Is virtually zero. In this case, if the entire device is kept at a very low temperature as in the conventional solid-state device shown in FIG. 8, electrons can be bound to the donor nucleus, and a sufficiently large existence probability | ψ (0) |²Can be obtained. Typically, the absolute temperature is maintained at about T = 100 mK. At this temperature, the electrons are bound to the lowest energy level (s state). By the way, the binding force is weak, the excitation energy to the first excitation level is about 15 meV, and is about 174K when converted to temperature.
[0041]
  In the present embodiment, due to the structure, electrons are confined inside the silicon single crystal fine particles 24. As a result, electrons are constrained by the potential well formed by the silicon single crystal fine particles 24 even if the entire device is not kept at a very low temperature. The wave function of an electron confined in a fine particle of radius a is the ground state (s state) wave function when the quantum size effect occurs because the radius a is sufficiently small.
                ψ (r) = Nj₀(r / a) (1)
It is represented by Where j₀Is the 0th order spherical Bessel function
                j₀(x) = sin (x) (1 / x) (2)
And has a maximum at x = 0. After all, the existence probability of electrons at r = 0 is
                  | ψ (0) |²∝a^-3
Therefore, in the present embodiment, the existence probability | ψ (0) |²Can be increased.
[0042]
  The energy difference ΔE between the first excited level and the ground level in the s state is about ΔE = 130 meV when the radius is 5 nm as a typical element dimension, and becomes 1508 K when converted to an absolute temperature. That is, the electron binding force can be increased by making the particle radius a sufficiently small. However, the mass is the static mass of electrons m_eo, Transverse mass in m_t, M_effM = (m_eff・ M_t ²)^1/3= 0.3216m_eoAnd the potential barrier depth at r = a is V₀= 3.15 eV was used analytically from the radial equation of Schroedinger's equation.
[0043]
  The quantum arithmetic element in the present embodiment is configured with cells made of silicon single crystal fine particles 24 to 27 exhibiting such contact hyperfine structure interaction. Therefore, it is possible to stably generate contact hyperfine structure interactions in individual cells.
[0044]
  Here, the quantum arithmetic element in the present embodiment functions as a memory that holds information of “0, 1” as the spin quantum number of the phosphorus nucleus in each of the silicon single crystal fine particles 24 to 27. For example, when reading the information held in the silicon single crystal fine particles 24, an electric potential is applied to the metal electrodes 29 to 31, and the electron clouds in the silicon single crystal fine particles 25 to 27 are exemplified as shown in FIG. 9. Is drawn toward the metal electrodes 29-31. Then, by holding the resonance frequency in that state, the retained information can be read out by the silicon single crystal fine particles 24 alone.
[0045]
  As described above, in the quantum arithmetic element according to the present embodiment, the silicon single crystal fine particles 24 to 27 are arranged on the silicon substrate 21 with the silicon oxide film 22 interposed at substantially equal intervals. The silicon single crystal fine particles 24 to 27 contain phosphorus atoms 32 to 35 as donor atoms, and the electron clouds of the respective phosphorus atoms 32 to 35 spread throughout the silicon single crystal fine particles 24 to 27. ing. Therefore, by reducing the radius of each silicon single crystal fine particle 24 to 27 to about 5 nm, the energy difference ΔE between the first excited level and the ground level in the s state is set to ΔE = 130 meV by the contact hyperfine structure interaction. The electrons can be kept in the ground level state more stably than in the bulk silicon single crystal.
[0046]
  That is, according to the present embodiment, electrons can be bound in the vicinity of the donor nucleus without being brought into a cryogenic state, and can be used without any problem in practice.
[0047]
  In the quantum operation element in the present embodiment, each of the silicon single crystal fine particles 24 to 27 constitutes a cell of the quantum operation element. 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.
[0048]
  <Second Embodiment>
  FIG. 2 is a schematic cross-sectional view of the quantum arithmetic element according to the present embodiment. On the first silicon oxide film 42 formed on the surface of the silicon substrate 41, a silicon single crystal particle array 44 is formed. The silicon single crystal fine particle array 44 is formed in such a manner that when a plurality of silicon single crystal fine particles are grown at substantially equal intervals in the same manner as in the first embodiment, the individual silicon single crystal fine particles come into contact with each other. Form by growing. Further, a second silicon oxide film 43 is formed on the first silicon oxide film 42 with the silicon single crystal particle rows 44 interposed therebetween, and the position of the silicon single crystal particle rows 44 is formed on the second silicon oxide film 43. A metal electrode film 45 is formed corresponding to the above.
[0049]
  The individual silicon single crystal particles constituting the silicon single crystal particle array 44 contain phosphorus atoms 46 to 50 as donor atoms. In the case of the present quantum arithmetic element, by reducing the radius of the silicon single crystal fine particles to about 5 nm, each phosphorus atom 46 is not applied to the metal electrode film 45 as shown in FIG. The electron cloud of ˜50 extends throughout the silicon single crystal fine particle array 44.
[0050]
  FIG. 3 shows only the portion of the silicon single crystal particle row 44 in FIG. FIG. 3A shows the state of the electron cloud when a potential is applied to the metal electrode film 45. FIG. 3B shows the state of the electron cloud when no potential is applied to the metal electrode film 45 (corresponding to FIG. 2B).
[0051]
  As shown in FIG. 3A, when a potential is applied to the metal electrode film 45, the electron cloud 51 is attracted to the metal electrode film 45 side, and each silicon single crystal constituting the silicon single crystal fine particle array 44 is drawn. The electron cloud 51 is separated by the convex portion 44a at the boundary of the crystal fine particles. In that case, the metal electrode film 45 is uniformly formed on all the silicon single crystal particles constituting the silicon single crystal particle row 44. Therefore, the electron cloud 51 is evenly distributed to 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 extends throughout the silicon single crystal particle array 44.
[0052]
  Therefore, if a plurality of the metal electrode films 45 are formed corresponding to each silicon single crystal fine particle constituting the silicon single crystal fine particle row 44 as in the first embodiment, the potential of each metal electrode is made independent. As a result, the magnitude of the exchange interaction between the nuclear spins in the silicon single crystal fine particles adjacent to each other constituting the silicon single crystal fine particle array 44 can be adjusted. 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 operation procedure of an appropriate potential.
[0053]
  In this case, only the metal electrodes corresponding to the conventional A gate 1 shown in FIG. Therefore, a control electrode corresponding to the conventional J gate 2 is not necessary.
[0054]
  Incidentally, in the quantum arithmetic element shown in FIG. 2, the metal electrode film 45 is uniformly formed on all the silicon single crystal particles constituting the silicon single crystal particle array 44. However, in the present invention, the positional relationship between the metal electrode film and the silicon single crystal fine particle row does not have to be as shown in FIG. 2, and there is no particular problem even if the positional relationship as shown in FIG. . In that case, the growth conditions can be used such that the silicon single crystal fine particles are sufficiently in contact with each other during the growth of the silicon single crystal fine particles. Reference numeral 61 denotes a silicon substrate, 62 and 63 denote silicon oxide films, 64 denotes a silicon single crystal fine particle array, 65 denotes a metal electrode film, and 66 denotes donor atoms (phosphorus atoms).
[0055]
  Further, as shown in FIG. 5, the metal electrode film 71 may be formed so as to partially cover the silicon single crystal fine particle array 72. In that case, a growth condition with a large number of growth nuclei of the silicon single crystal fine particles can be used during the growth of the silicon single crystal fine particles. Further, as shown in FIG. 6, one metal electrode film 75 may be formed so as to cover the whole of the plurality of silicon single crystal fine particle rows 76 and 77. In that case, a growth condition with a small number of growth nuclei of the silicon single crystal fine particles can be used during the growth of the silicon single crystal fine particles.
[0056]
  In the first embodiment and the second embodiment, when each silicon single crystal fine particle is formed to have a diameter of 10 nm or less, if phosphorus atoms as impurity atoms are mixed at an appropriate low concentration, It can be considered that only one phosphorus atom as a donor atom is contained in each silicon single crystal fine particle. Therefore, in that case, one nuclear spin can be operated independently, and the quantum mechanical superposition state can be utilized.
[0057]
  On the other hand, when the diameter of each silicon single crystal fine particle is formed to be larger than 10 nm, in order to make only one phosphorus atom exist in each silicon single crystal fine particle, an impurity atom is used. Certain phosphorus atoms must be mixed in at a very 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.
[0058]
  <Third Embodiment>
  FIG. 7 is an overhead view in the present embodiment. The quantum arithmetic elements in the first and second embodiments need to continue to apply a static magnetic field to the entire element when manipulating nuclear spins using contact hyperfine interactions.
[0059]
  Therefore, in the present embodiment, as in the first and second embodiments, the integrated circuit chip 81 in which the quantum operation element is formed using the normal integrated circuit technology is sandwiched between the magnetic chips 82 and 83 and bonded. To do. By doing so, a static magnetic field can be stably applied to the quantum operation element built in the integrated circuit chip 81.
[0060]
  In addition, only the integrated circuit chip on which the quantum arithmetic element in the first and second embodiments is formed is a circuit.substrateIf it is mounted onsubstrateThe entirety may be sandwiched between magnetic materials and bonded.
[0061]
【The invention's effect】
  As is clear from the above, the quantum arithmetic element according to the first aspect of the present invention has the silicon single crystal fine particles arranged on the first insulating film formed on the substrate, and further the second insulating film sandwiched between the silicon single crystal fine particles. And forming a metal electrode on at least the position of the silicon single crystal fine particles on the second insulating film,,As an impurityThe concentration of the silicon single crystal fine particles can be regarded as containing only one atom.Since phosphorus atoms are included, phosphorus electrons as donor atoms are bound by the potential well formed by the silicon single crystal fine particles. Therefore, electrons can be bound to the vicinity of the donor nucleus without being brought into a cryogenic state, and can be used without any problem in practice.
[0062]
  Furthermore, the silicon single crystal fine particles constitute a cell of the present quantum arithmetic element, and the position of the cell is determined by the mechanical shape. Therefore, the metal electrode can be easily and accurately formed on each donor atom by using a conventional photolithography technique or self-alignment technique. As a result, this quantum arithmetic element can be easily formed.
[0063]
  Furthermore, if a potential is applied to the metal electrode, an electron cloud of phosphorus atoms in the silicon single crystal fine particles can be attracted 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.
[0064]
  In the quantum arithmetic element according to the second aspect of the present invention, a silicon single crystal fine particle array in which a plurality of silicon single crystal fine particles are connected to each other is disposed on a first insulating film formed on a substrate, and the silicon single crystal A second insulating film is formed across the crystal particle rows, and a metal film is formed at least at the position of the silicon single crystal particle rows on the second insulating film.,As an impurityThe concentration of the silicon single crystal fine particles can be regarded as containing only one atom.Since it contains phosphorus atoms, as in the case of claim 1, electrons can be bound in the vicinity of donor nuclei without being brought into a cryogenic state, and can be used without any problem in practice. 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 self-alignment technique. . As a result, this quantum arithmetic element can be easily formed.
[0065]
  Further, when an electric 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 array, When no potential is applied to the metal film, the electron cloud of phosphorus spreads over the entire silicon single crystal fine particle array. Therefore, by controlling the potential of the metal film, electrons between a plurality of phosphorus atoms are used as a medium. Allows exchange of nuclear spins.
[0066]
  The quantum arithmetic element according to the first or second aspect of the present invention is the isotopic isotope of the silicon single crystal fine particles.²⁸Si and isotopes³⁰If composed of silicon atoms with Si, the silicon single crystal fine particles have an isotope having a nuclear spin quantum number of 1/2.²⁹Si is not included. Therefore, natural isotopes³¹It is possible to easily detect the difference in the nuclear spin of a phosphorus atom having P of 100% and a nuclear spin quantum number of 1/2.
[0067]
  In the quantum arithmetic element according to the first or second invention, when the diameter of each silicon single crystal fine particle is 10 nm or less, phosphorus atoms as impurity atoms are mixed at an appropriate low concentration. It can be considered that only one donor atom is contained in each silicon single crystal fine particle. Therefore, one nuclear spin can be operated independently, and the quantum mechanical superposition state can be utilized.
[0068]
  In the quantum arithmetic element according to the second aspect of the present invention, 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 array, the potentials of the plurality of metal films are formed. , The spin state of a certain phosphorus nucleus can be transferred to adjacent phosphorus nuclei one after another. Therefore, a desired calculation operation can be performed by giving an appropriate operation procedure.
[0069]
  In the integrated circuit of the third invention, since the integrated circuit chip on which the quantum arithmetic element of the first or second invention is mounted is sandwiched between magnetic chips, no special magnetic field applying means is provided. In addition, a static magnetic field can be stably applied to the whole quantum arithmetic element on the integrated circuit chip by the magnetic chip without requiring electric power. In other words, according to the present invention, it is possible to manipulate nuclear spins using the contact hyperfine interaction with this integrated circuit alone.
[0070]
  An integrated circuit device according to a fourth aspect of the invention is a circuit on which an integrated circuit chip on which the quantum arithmetic element of the first or second aspect of the invention is formed is mountedsubstrateAre sandwiched between magnetic bodies, so that a static magnetic field can be stably applied to the whole quantum arithmetic element on the integrated circuit chip by the magnetic body without providing a special magnetic field applying means. Therefore, according to the present invention, it is possible to manipulate the nuclear spin by utilizing the contact hyperfine interaction with this integrated circuit device alone.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a quantum arithmetic element according to the present invention.
FIG. 2 is a schematic cross-sectional view of a quantum operation element different from FIG.
FIG. 3 is a diagram showing changes in the state of the electron cloud in FIG. 2;
4 is a diagram showing a positional relationship between a metal electrode film different from FIG. 2 and a silicon single crystal fine particle array.
FIG. 5 is a diagram showing a positional relationship between a metal electrode film different from FIGS. 2 and 4 and a silicon single crystal fine particle array.
6 is a diagram showing a positional relationship between a metal electrode film different from FIGS. 2, 4 and 5 and a silicon single crystal fine particle array. FIG.
7 is a diagram showing a circuit chip in which an integrated circuit chip on which the quantum operation element shown in FIGS. 1 to 6 is formed is sandwiched with a magnetic chip and bonded. FIG.
FIG. 8 is a diagram showing a structure of a solid state device using a conventional 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 in FIG. 8 and a potential is further applied to one of the J gates.
[Explanation of symbols]
21, 41, 61 ... silicon substrate,
22, 23, 42, 43, 62, 63 ... silicon oxide film,
24-27 ... Silicon single crystal fine particles,
28-31 ... Metal electrode,
32-35, 46-50, 66 ... donor atom (phosphorus atom),
44, 64, 72, 76, 77 ... Silicon single crystal fine particle rows,
45, 65, 71, 75 ... metal electrode film,
51,52 ... electron cloud,
81 ... integrated circuit chip,
82, 83: Magnetic chip.

Claims (10)

A first insulating film formed on the substrate;
Silicon single crystal fine particles disposed on the first insulating film;
A second insulating film formed on the first insulating film with the silicon single crystal fine particles interposed therebetween;
A metal electrode formed on at least the position of the silicon single crystal fine particles on the second insulating film;
Some of the silicon single crystal particles, as an impurity, quantum computation device characterized by atoms in the silicon single crystal particles contain phosphorus atoms concentration can be considered to contain only one . A first insulating film formed on the substrate;
A single-crystal silicon particle array in which a plurality of single-crystal silicon particles arranged on the first insulating film are connected to each other;
A second insulating film formed on the first insulating film with the silicon single crystal fine particle rows interposed therebetween;
A metal film formed on at least the position of the silicon single crystal fine particle row on the second insulating film;
Among the above silicon single crystal particles, as an impurity, quantum computation, characterized in that atoms in the silicon single crystal particles contains one only contained a concentration that can be regarded as phosphorus atoms element. In the quantum arithmetic element according to claim 1 or 2,
A quantum computing element, wherein silicon atoms constituting the silicon single crystal fine particles are composed of isotopes ²⁸ Si and isotopes ³⁰ Si. In the quantum arithmetic element according to claim 3,
The quantum arithmetic element according to claim 1, wherein the silicon single crystal fine particles have a diameter of 10 nm or less. The quantum arithmetic element according to claim 2,
A quantum computing element, 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 array. The quantum arithmetic element according to claim 2,
The quantum arithmetic element, wherein the metal film is formed to cover the entire silicon single crystal fine particle array. The quantum arithmetic element according to claim 6,
A quantum computation element comprising a plurality of silicon single crystal fine particle arrays covered with the metal film. The quantum arithmetic element according to claim 2,
The quantum arithmetic element, wherein the metal film is formed so as to cover a part of the silicon single crystal fine particle array.   6. An integrated circuit comprising: an integrated circuit chip on which the quantum arithmetic element according to claim 1 is mounted, which is sandwiched between magnetic chips. 6. An integrated circuit device comprising a circuit board on which an integrated circuit chip on which the quantum operation element according to claim 1 is formed is sandwiched between magnetic bodies.

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