KR20230089712A - Manufacturing Method for Nano-Hole Shadow Mask and Manufacturing Method for Manufacturing Single Color Center Array Using the Same - Google Patents

Abstract

A method of manufacturing a shadow mask for manufacturing a single color center array, comprising: attaching a metal thin film to a shadow mask frame; and forming nano holes by irradiating the metal thin film with a focused ion beam, wherein the size of the nano holes is 290 to 320 nm or less, a method for manufacturing a shadow mask, and the prepared shadow mask is a sample of non-conductive inorganic crystals. Step of positioning on the shadow mask; Forming a lattice defect (lattice defect) by irradiating an ion beam to the sample of the non-conductive inorganic crystal where the shadow mask is located; forming a color center by irradiating a low-dose ion beam to a non-conductive inorganic crystal sample on which the shadow mask having the lattice defect is located; It relates to a method for manufacturing a single color center array, including; and heat-treating.

Description

Manufacturing Method for Nano-Hole Shadow Mask and Manufacturing Method for Manufacturing Single Color Center Array Using the Same}

The present invention relates to a method for manufacturing a nano hole shadow mask and a method for manufacturing a single color center array using a nano hole shadow mask and a low dose irradiation method.

Color centers are defects that exist in non-conductive inorganic crystals, and light is emitted through the energy level difference of electrons generated in these defects. A wide variety of color centers have been studied, and the most widely used in quantum optics is the nitrogen-vacancy color center (NV color center) existing in diamond. It is a defect that is easily found in diamond crystals and is formed when a nitrogen atom is placed next to a carbon vacancy.

Since the color center, a point defect in diamond, can control various quantum states of electron spin at room temperature, the color center of diamond is in the spotlight as a material for manufacturing an ideal single-photon light source and next-generation quantum information communication. there is. In particular, research to utilize the color center as a quantum bit (Qubit), the minimum information processing unit of a quantum computer, is actively underway.

The color center is fabricated by implanting an ion beam into the diamond. It is necessary to be able to inject one atom into a desired point, and it is advantageous to manufacture a device if the injecting point is implemented in the form of an array. Therefore, single color center array fabrication technology can be said to be the core of color center-based qubit implementation.

However, although it is easy to control the quantum state of electron spin at room temperature through the color center-based quantum technology, the color center-based quantum technology is not widely used industrially because of the high difficulty of device fabrication.

Conventionally, in order to fabricate a single color center array, a single ion implantation technique or a method combining nanopatterning and ultra-low dose ion beam irradiation has been used. Single ion implantation technology is a technology that drills a small hole in the cantilever of AFM (Atomic Force Microscopy), sweeps an ion beam through the hole, and implants only one ion at a desired location with a certain probability. Although this technique has high positional accuracy, it takes a lot of time and effort to fabricate many single color center arrays.

On the other hand, in a method combining nanopatterning and low-dose ion beam irradiation, a circular pattern array having a diameter of tens to hundreds of nm is first prepared by using electron beam lithography or photolithography on diamond, Thereafter, the diamond portion without a circular pattern is continuously etched through an etching process, and finally, a plurality of diamond columnar arrays are produced. If a low-dose ion beam is injected here, it is possible to inject only one ion into a diamond cylinder with a certain probability, and it is a method of manufacturing a single color center array using this. This method has disadvantages in that it takes a long time to manufacture the diamond cylinder array and it is difficult to construct an optical system.

Accordingly, there is a need for a simpler single-color centered array manufacturing process technology that solves the problems of the prior art and enables the manufacture of a single-color centered array within a short period of time.

The present invention is to solve the above-mentioned problems, and is a shadow mask for manufacturing a single color center array and a method for manufacturing a single color center array using the same, comprising: attaching a metal thin film to a shadow mask frame; and irradiating the metal thin film with a focused ion beam to form nano holes. It provides a method for manufacturing a shadow mask, wherein the size of the nano-holes is 290 to 320 nm or less.

In addition, placing the shadow mask manufactured according to the manufacturing method on the sample of non-conductive inorganic crystals; irradiating an ion beam to the diamond sample where the shadow mask is located to form a lattice defect; forming a color center by irradiating a diamond sample with a low-dose ion beam on which the shadow mask having the lattice defects is located; And heat treatment; provides a method of manufacturing a single color center array, including a.

According to one embodiment of the present invention, there is provided a method of manufacturing a shadow mask for manufacturing a single color center array, comprising: attaching a metal thin film to a shadow mask frame; and forming nano-holes by irradiating the metal thin film with a focused ion beam, wherein the nano-holes have a size of 290 to 320 nm or less.

The metal of the metal thin film may include at least one selected from the group consisting of copper, iron, nickel, chromium, cobalt, and mixtures thereof.

The metal thin film may have a thickness of 2 to 4 μm.

An irradiation energy of the focused ion beam may be 5 to 30 keV.

According to another embodiment of the present invention, placing a shadow mask manufactured according to the present invention on a sample of non-conductive inorganic crystals; forming a lattice defect by irradiating an ion beam to a sample of non-conductive inorganic crystal where the shadow mask is located; forming a color center by irradiating a low-dose ion beam to a sample of a non-conductive inorganic crystal on which the shadow mask having the lattice defect is located; And heat treatment step; may be to include.

The non-conductive inorganic crystal sample may be diamond or silicon carbide.

In the step of forming the lattice defect, ions of the ion beam may include at least one selected from the group consisting of carbon, helium, and neon.

An irradiation amount of the ion beam may be 10 ¹⁴ to 10 ¹⁶ ions/cm 2 .

The lattice defects may be carbon vacancies or silicon vacancies.

In the step of forming the color center, the low-dose ion beam may include at least one selected from the group consisting of nitrogen, silicon, and germanium.

The low-dose ion beam may have an irradiation amount of 1 x 10 ⁸ to 1 x 10 ¹⁰ ions/cm 2 .

An irradiation angle of the ion beam in the forming of the lattice defect and the low-dose ion beam in the forming of the color center may be 6 degrees or less.

According to the method of manufacturing a nano hole shadow mask and the method of manufacturing a single color center array using the same of the present invention, a nano hole shadow mask is prepared through a simple process of irradiating a metal thin film with a focused ion beam and applied to an inorganic crystal sample, There is an effect of forming a single color center array accurately and simply in a short time without a separate additional process such as etching of an inorganic crystal sample. In addition, the single color center array prepared as described above has an effect that can be used industrially as a quantum computer and a quantum sensor.

1 is a diagram illustrating a manufacturing process of a nano hole shadow mask according to an embodiment of the present invention.
2 is a diagram illustrating a manufacturing process of a single color center array according to an embodiment of the present invention.
3A to 3D are cross-sectional and plan views of a nano hole shadow mask manufactured according to Example 1;
4 is a PL mapping result for confirming a single color center arrangement in a diamond sample prepared according to Example 2.
5 is a diagram showing the PL characteristics of the nitrogen-vacancy color center according to the amount of carbon vacancies.

Hereinafter, with reference to the accompanying drawings, a method of manufacturing a nano hole shadow mask and a method of manufacturing a single color center array using the method of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. Explain.

A method of manufacturing a nano hole shadow mask according to an embodiment of the present invention is a method of manufacturing a shadow mask for manufacturing a single color center array, comprising the steps of attaching a metal thin film to a shadow mask frame; and forming nano-holes by irradiating the metal thin film with a focused ion beam, wherein the nano-holes have a size of 290 to 320 nm or less.

In the step of attaching the metal thin film to the shadow mask frame, metal materials such as steel and aluminum, metal alloys, functional polymers such as polycarbonate, glass materials, ceramic materials, etc. may be used as the shadow mask frame, but the material of the frame is not particularly limited as long as it can stably secure the area of the metal thin film to which the focused ion beam is irradiated.

The attachment can be simply attached using welding, adhesive, adhesive tape, etc., and is not particularly limited as long as it can secure the adhesion between the shadow mask frame and the metal thin film.

The metal of the metal thin film may include at least one selected from the group consisting of copper, iron, nickel, chromium, cobalt, and mixtures thereof. The metal thin film may be applied without being limited thereto, as long as it is not damaged and can be repeatedly used even when continuously irradiated with high-energy ion beams to form nano-holes.

The thickness of the metal thin film may be 2 to 4 μm, preferably 2.5 to 3.5 μm or less. If the thickness of the metal thin film exceeds the upper limit of the numerical range, it may be difficult to manufacture nano-sized holes, and if the thickness is less than the lower limit, the thin film may be too thin and difficult to handle.

In order to manufacture a nano-hole shadow mask, that is, to form nano-holes in the shadow mask, a metal thin film having a thickness of 2 to 4 μm or less is attached to the shadow mask, and the thickness of the metal thin film attached using a focused ion beam or ion milling technology. It can be manufactured by making it thin to 1 μm or less and then irradiating a focused ion beam.

A ratio of the thickness of the metal thin film to the diameter of the nanohole formed in the shadow mask may be 8:1 to 12:1, preferably 9:1 to 11:1. If the ratio of the thickness of the metal thin film and the diameter of the nanoholes formed in the shadow mask exceeds the upper limit, the fragments of the metal thin film removed by the focused ion beam in the process of forming nanoholes in the metal thin film by irradiating the focused ion beam are scattered through the nanohole holes. In the process of irradiating the low-dose ion beam to form a single color center array, the low-dose ion beam passes through the nano-holes because the diameter of the nano-holes becomes smaller than the intended size. There may be cases where you cannot. In addition, if the ratio of the thickness of the metal thin film and the diameter of the nanoholes formed in the shadow mask is less than the lower limit, a problem in that the nanoholes themselves may not be formed may occur.

The focused ion beam (FIB) may include at least one ion source selected from the group consisting of gallium, neon, helium, cesium, francium, rubidium, phosphorus, and potassium. may include In the case of general metals, since their melting point is very high, a high current must be applied to melt them. In a solid state, the bonding force between atoms is very strong, so it may not be easy to release ions even if an external electric field is applied. On the other hand, since gallium has a melting point near room temperature, it can easily melt and release ions even when a small amount of current flows.

The irradiation energy of the focused ion beam may be 2 to 40 keV, preferably 5 to 30 keV. When the irradiation energy of the focused ion beam has a value within the numerical range, it is possible to precisely manufacture nano-holes, thereby increasing manufacturing efficiency.

The nanoholes formed by irradiation of the focused ion beam may have a size of 290 to 320 nm, preferably 295 to 305 nm. The size of the hole may be manufactured to 300 nm or less by applying a thinner metal thin film, and the thickness of the metal thin film may be adjusted through the focused ion beam.

A method of manufacturing a single color center array using a nano hole shadow mask according to an embodiment of the present invention includes placing the shadow mask manufactured according to the shadow mask manufacturing method on a sample of non-conductive inorganic crystals; forming a lattice defect by irradiating an ion beam to a sample of non-conductive inorganic crystal where the shadow mask is located; forming a color center by irradiating a low-dose ion beam to a non-conductive inorganic crystal sample on which the shadow mask having the lattice defect is located; And heat-treating; provides a method of manufacturing a single color center array, including a.

A color center is a structural defect in a non-conductive inorganic crystal. Atoms are regularly arranged in a solid crystal. If an atom is not present in a position where an atom already exists or is substituted with another atom, it becomes a defect in the crystal. It is called The color center can also be created artificially. When particles such as electrons or neutrons strike a crystal or when strong electromagnetic waves such as gamma rays are irradiated to the crystal structure and the impact creates defects in the crystal lattice, the defects can become color centers.

Representative non-conductive inorganic crystal lattices capable of forming color centers include diamond and silicon carbide (SiC). Diamond is a crystal in which carbon atoms are regularly arranged, and like other crystal structures, various defects may exist, and specifically, carbon atoms in the crystal structure may be missing to form vacancies. Some carbon atoms can be replaced by other atoms, especially nitrogen atoms. Because nitrogen atoms have one more outermost electron than carbon atoms, it is more stable to find a vacancy next to a carbon atom than to be alone. can The resulting nitrogen-vacancy defect is called a nitrogen-vacancy color center.

One of the most important reasons why the diamond nitrogen-vacancy color center can be used to control various quantum states is that the energy structure of the diamond nitrogen-vacancy color center is degeneracy in the ground state. Specifically, they form a spin triplet and are separated by a minute energy difference corresponding to a 2.88 GHz microwave by spin-spin interaction. Therefore, by well controlling the transition between these energy levels, the ground state spin triplet state can be quantum controlled.

In addition, carbon (C ¹² ), an atom constituting diamond, has a relatively low valence and has a very weak spin-angular momentum interaction. Therefore, it can provide an environment in which the spins are well separated from the lattice. In addition, the strong bonding between the carbon atoms that make up diamond causes relatively weak lattice vibrations, providing a low-temperature environment in which thermal fluctuations are excluded even at room temperature, and a nucleus that destroys spin coherence through interaction with electron spins. It can act as a system in which C ¹³ with spin exists relatively little.

For the above reasons, the electronic structure of the diamond nitrogen-vacancy color center has a very narrow line width at the level of atomic physics, and can have excellent cycling transition characteristics and fluorescence characteristics.

Silicon carbide (SiC) is a semiconductor containing silicon and carbon and can form a color center in a crystal lattice like diamond. Specifically, silicon carbide can interact optically with energies below the band gap energy to form color centers with quantum properties that can be activated. In addition, silicon carbide may have optically activated spin qubits, and may have long coherence time and quantum properties capable of room temperature control.

A lattice defect means an irregular disorder that can occur in the arrangement of atoms in a crystal, and this can have a great effect on various physical and chemical properties of the crystal, as well as exhibit unique phenomena or actions.

General lattice defects can be classified into plane defects, line defects, and point defects according to their shapes. Plane defects may be external and internal surfaces of crystals, that is, grain boundaries, bonding surfaces of twin crystals, stacking flaws, etc., and linear defects may be secondary defects caused by straight alignment of misalignment and point defects. Point defects may be impurity atoms, vacancies, interstitial atoms, and the like.

In the method for producing a single color center array according to the present invention, the lattice defect formed in the non-conductive inorganic crystal sample may be a point defect, preferably an atomic vacancy, more preferably a carbon atom vacancy or a silicon vacancy.

Ions of the ion beam in the step of forming the lattice defect may include at least one selected from the group consisting of carbon, helium, and neon, and preferably may be helium. The helium ion beam has the advantage of low energy dispersion because the light source is composed of almost single atoms.

In addition, the irradiation energy of the ion beam in the step of forming the lattice defect may be 80 to 120 KeV, preferably 90 to 110 KeV. When the irradiation energy of the ion beam exceeds the upper limit of the numerical range, a long time is required to form lattice defects. There may be problems that increase the probability of being.

An irradiation amount of the ion beam in the step of forming the lattice defect may be 1 x 10 ¹⁴ to 1 x 10 ¹⁶ ions/cm 2 , preferably 5 x 10 ¹⁴ to 5 x 10 ¹⁵ ions/cm 2 . When the irradiation amount of the ion beam exceeds the upper limit of the numerical range, it may not be easy to recover the crystal structure of the non-conductive inorganic crystal sample, and when the irradiation amount is less than the lower limit, an appropriate amount of carbon vacancy is not formed, resulting in color center generation efficiency. This degradation may cause problems.

In the step of forming the color center, the low-dose ion beam may include at least one selected from the group consisting of nitrogen, silicon, and germanium, and may preferably be nitrogen. A single ion may be implanted into a lattice defect of the non-conductive inorganic sample by irradiating the low-dose ion beam.

The irradiation energy of the low-dose ion beam may be 30 to 70 KeV, preferably 40 to 60 KeV. When the irradiation energy of the ion beam exceeds the upper limit value, an error of 40 nm or more is shown at the position where the single color center is formed, and thus the accuracy of the position where the single color center is formed may deteriorate.

The low-dose ion beam may have an irradiation dose of 1 x 10 ⁸ to 1 x 10 ¹⁰ ions/cm 2 , preferably 1 x 10 ⁹ to 5 x 10 ⁹ ions/cm 2 . When the irradiation amount of the ion beam exceeds the upper limit value or does not reach the lower limit value, a single color center may not be formed.

An irradiation angle of the ion beam in the forming of the lattice defect and the low-dose ion beam in the forming of the color center may be 6 degrees or less. Specifically, when the angle formed by the low-dose ion beam and the nanoholes of the shadow mask is 6 degrees or more, the low-dose ion beam is not incident, so that a single color center array cannot be formed on the non-conductive inorganic crystal sample.

Heat treatment may be performed after irradiation with the low-dose ion beam. Through the heat treatment process, a single color center array may be formed in the non-conductive inorganic crystal sample irradiated with the ion beam. The heat treatment may be performed at a temperature of 800° C. or more for 1 hour or more in the presence of vacuum or an inert gas such as argon or nitrogen gas.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

<Example 1> Preparation of nano hole shadow mask

First, a shadow mask frame having a thickness of 300 μm was prepared, and a copper thin film of 3 μm was attached to the shadow mask frame. Thereafter, the copper thin film is irradiated with a focused ion beam using gallium ions (Ga ⁺ ) as an ion source at an energy of 5 to 30 keV to have a 5 x 5 hole array as shown in FIGS. 3A to 3D, and each array The constituting hole diameter was 300 nm, 0.6 μm, 1 μm, and 1.5 μm, and four types of nano hole shadow masks were fabricated.

<Example 2> Preparation of single color center array using nano hole shadow mask

A diamond sample (SC CVD plates, Electronic Grade (100), Applied Diamond, Inc.) was prepared, the shadow mask with a hole diameter of 300 nm prepared in Example 1 was placed on the sample, and a 100 KeV helium ion beam was applied to the sample. 10 ¹⁴ , 1 x 10 ¹⁵ , and 1 x 10 ¹⁶ ions/cm 2 were irradiated to form carbon vacancies in the diamond crystal lattice according to each irradiation energy. Thereafter, a 50 KeV nitrogen ion beam was irradiated with an irradiation amount of 1.2 x 10 ⁹ ions/cm 2 , and heat treatment was performed to form a nitrogen-vacancy color center.

<Example 3> PL mapping result

In order to measure PL mapping for the single color center array prepared according to Example 2, PL mapping was performed at room temperature and pressure using HORIBA's LabRAM HR Evolution Visible_NIR. Excitation was performed using a 532 nm laser, and PL mapping was performed based on the intensity of 638 nm, which is the zero-phonon line of the nitrogen vacancy. The measurement was performed while moving horizontally and vertically by 0.5 μm.

As a result of PL mapping, it can be clearly confirmed that a nitrogen-vacancy color center arrangement is generated in the diamond sample, as shown in FIG. 4a.

In addition, as a result of measuring the PL intensity according to the irradiation amount of the helium ion beam, the case of irradiation with an irradiation amount of 1 x 10 ¹⁵ ions/cm2 showed the strongest zero-phonon line (see FIG. 5), which is the nitrogen-vacancy color under the conditions of the irradiation amount It can be seen that the center is best formed. In other words ^, 1 x 10 ¹⁵ ions/cm2 is the optimal amount of radiation that can form the most carbon vacancies on the crystal structure of a diamond sample. It is formed in large quantities.

On the other hand, when an irradiation amount of 1 x 10 ¹⁵ ions/cm2 or more is not easy to recover the diamond crystal structure, the color center is not properly formed, resulting in the zero-phonon line of NV ⁰ (575nm) and NV ^- (638nm). It was found that the signal was significantly weakened.

Claims (12)

of shadow mask for single color center array production
As a manufacturing method,
attaching a metal thin film to the shadow mask frame; and
forming nano holes by irradiating the metal thin film with a focused ion beam;
including,
The method of manufacturing a shadow mask, wherein the size of the nano-holes is 290 to 320 nm. The method of claim 1,
The metal of the metal thin film includes at least one selected from the group consisting of copper, iron, nickel, chromium, cobalt, and mixtures thereof. The method of claim 1,
A method of manufacturing a shadow mask in which the thickness of the metal thin film is 2 to 4 μm. The method of claim 1,
The method of manufacturing a shadow mask wherein the irradiation energy of the focused ion beam is 5 to 30 keV. placing a shadow mask prepared according to claims 1 to 4 on a sample of non-conductive inorganic crystals;
forming a lattice defect by irradiating an ion beam to a sample of non-conductive inorganic crystal where the shadow mask is located;
forming a color center by irradiating a low-dose ion beam to a non-conductive inorganic crystal sample on which the shadow mask having the lattice defect is located; and
heat treatment;
A manufacturing method of a single color center array comprising a. The method of claim 5,
The method of producing a single color center array in which the non-conductive inorganic crystal sample is diamond or silicon carbide. The method of claim 5,
In the step of forming the lattice defect, the ions of the ion beam include at least one selected from the group consisting of carbon, helium, and neon. The method of claim 7,
The method of manufacturing a single color center array in which the irradiation amount of the ion beam is 10 ¹⁴ to 10 ¹⁶ ions/cm 2 . The method of claim 5,
The method of manufacturing a single color center array in which the lattice defect is a carbon vacancy or a silicon vacancy. The method of claim 5,
In the step of forming the color center, the low-dose ion beam includes at least one selected from the group consisting of nitrogen, silicon, and germanium. The method of claim 10,
The method of manufacturing a single color center array in which the low-dose ion beam has an irradiation amount of 1 x 10 ⁸ to 1 x 10 ¹⁰ ions/cm 2 or less. The method of claim 5,
A method of manufacturing a single color center array in which an irradiation angle of the ion beam in the step of forming the lattice defect and the low-dose ion beam in the step of forming the color center is 6 degrees or less.

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