Quantum device and manufacturing method therefor

Abstract

The present invention relates to a quantum device and a manufacturing method therefor. The quantum device according to the present invention comprises: a substrate; a lower metal electrode formed on the substrate; a graphene oxide layer, which is formed on the lower metal electrode and has insulation properties; and an upper metal electrode formed on the graphene oxide layer. According to the present invention, graphene oxide having insulation properties is applied to an insulating layer of the quantum device such that the thickness can be maintained to be more consistent and smaller than that of a conventional insulating layer using a metal oxide film, and, in a manufacturing process, the graphene oxide layer is formed using a method that is compatible with a conventional semiconductor process such that the thickness and quality of the insulating layer can be optimized.

Description

Quantum device and its manufacturing method

[0001] The present invention relates to a quantum device and a method for manufacturing the same. More specifically, the present invention relates to a quantum device and a method for manufacturing the same, which can efficiently form an insulating layer in a quantum device having a superconductor-insulator-superconductor structure and optimize the resulting quantum tunneling effect.

[0002] Quantum devices play a crucial role in modern ultra-high-speed computing and information processing.

[0003] One of the key components of these quantum devices is the superconductor-insulator-superconductor structure, and the quantum tunneling effect, especially in the intermediate insulating layer, has a critical impact on the performance of the quantum device.

[0004] According to the conventional quantum device manufacturing method, a metal oxide film is used as an insulating layer, and since the resonance frequency of the quantum device changes depending on the thickness of the metal oxide film in the superconducting quantum device, precise thickness control of the insulating layer is essential.

[0005] However, according to the conventional technology, there was a problem of thickness consistency in the manufacturing of the insulating layer of a quantum device using a metal oxide film, which resulted in a problem of deterioration in the consistency of the quantum tunneling effect and the performance of the entire quantum device.

[0006] [Prior Art Literature]

[0007] Republic of Korea Patent No. 10-0939767 (Registration date: January 25, 2010, Title: Manufacturing method of single electronic device)

[0008] The technical problem of the present invention is to provide a quantum device and a manufacturing method thereof that can prevent the problem of thickness consistency that occurs in the manufacturing of an insulating layer of a quantum device using a conventional metal oxide film, and the risk of deterioration of the consistency of the quantum tunneling effect and the performance of the entire quantum device due to this.

[0009] A more specific technical task of the present invention is to provide a quantum device and a manufacturing method thereof, which can maintain a consistent and low thickness compared to an insulating layer using a conventional metal oxide film by applying graphene oxide having insulating properties to the insulating layer of a quantum device, and can optimize the thickness and quality of the insulating layer by forming the graphene oxide layer in a manner compatible with the existing semiconductor process during the manufacturing process.

[0010] A quantum device according to the present invention for solving these technical problems includes a substrate, a lower metal electrode formed on the substrate, a graphene oxide layer formed on the lower metal electrode and having insulating properties, and an upper metal electrode formed on the graphene oxide layer.

[0011] In the quantum device according to the present invention, the thickness of the graphene oxide layer is characterized by being 10 μm or less.

[0012] In the quantum device according to the present invention, the thickness of the graphene oxide layer is characterized by being 1 nm or more.

[0013] In the quantum device according to the present invention, the lower metal electrode and the upper metal electrode are characterized in that they are superconductors.

[0014] In the quantum device according to the present invention, the lower metal electrode and the upper metal electrode are characterized in that they form a Josephson junction by the graphene oxide layer.

[0015] In the quantum device according to the present invention, the lower metal electrode and the upper metal electrode are characterized in that they are made of a metal selected from among aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or an alloy selected from among niobium-titanium alloy (NbTi), niobium-tin alloy (NbSn), or barium-bismuth-oxide (BaBiO3).

[0016] A method for manufacturing a quantum device according to one aspect of the present invention includes a lower metal electrode forming step of forming a lower metal electrode on a substrate, a graphene layer deposition step of depositing a graphene layer on the lower metal electrode, a graphene layer oxidation step of exposing the graphene layer deposited on the lower electrode to oxygen radicals to adsorb the oxygen radicals onto the graphene layer to oxidize the graphene layer and form a graphene oxide layer, and an upper metal electrode forming step of forming an upper metal electrode on the graphene oxide layer.

[0017] A method for manufacturing a quantum device according to another aspect of the present invention includes a lower metal electrode forming step of forming a lower metal electrode on a substrate, a graphene oxide coating step of coating a graphene oxide solution on the lower metal electrode, a graphene oxide reduction step of forming a graphene oxide layer on the lower metal electrode by reducing the graphene oxide solution coated on the lower metal electrode using a chemical reduction method or a thermal reduction method, and an upper metal electrode forming step of forming an upper metal electrode on the graphene oxide layer.

[0018] In a method for manufacturing a quantum device according to both aspects of the present invention, it is characterized in that at least one of the lower metal electrode forming step and the upper metal electrode forming step uses a metal etching or lift-off method.

[0019] In a method for manufacturing a quantum device according to both aspects of the present invention, the thickness of the graphene oxide layer is characterized by being 10 μm or less.

[0020] In a method for manufacturing a quantum device according to both aspects of the present invention, the thickness of the graphene oxide layer is characterized by being 1 nm or more.

[0021] In a method for manufacturing a quantum device according to both aspects of the present invention, the lower metal electrode and the upper metal electrode are characterized in that they are superconductors.

[0022] In a method for manufacturing a quantum device according to both aspects of the present invention, the lower metal electrode and the upper metal electrode are characterized in that they form a Josephson junction by the graphene oxide layer.

[0023] In the method for manufacturing a quantum device according to both aspects of the present invention, the lower metal electrode and the upper metal electrode are characterized in that they are made of a metal selected from among aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or an alloy selected from among niobium-titanium alloy (NbTi), niobium-tin alloy (NbSn), or barium-bismuth-oxide (BaBiO3).

[0024] According to the present invention, there is provided a quantum device and a method for manufacturing the same, which can prevent problems of thickness consistency that occur in the manufacturing of an insulating layer of a quantum device using a conventional metal oxide film, and thereby reduce the consistency of the quantum tunneling effect and the performance of the entire quantum device.

[0025] In addition, by applying graphene oxide, which has insulating properties, to the insulating layer of the quantum device, a consistent and low thickness can be maintained compared to an insulating layer using a conventional metal oxide film, and during the manufacturing process, the thickness and quality of the insulating layer can be optimized by forming the graphene oxide layer in a manner compatible with the existing semiconductor process.

[0026] Additionally, the application of graphene oxide has the effect of improving the consistency of the quantum tunneling effect, which can improve the overall performance of the quantum device.

[0027] In addition, compared to conventional metal oxide films, graphene oxide has the property of maintaining a more uniform and thinner thickness, which can significantly reduce the defect rate in the manufacturing process of quantum devices and shorten the manufacturing time. This improved manufacturing efficiency can lead to a reduction in production costs, which can have the effect of bringing about economic benefits.

[0028] FIG. 1 is a cross-sectional view of a quantum device according to an embodiment of the present invention.

[0029] Figure 2 is a top view of a quantum device according to an embodiment of the present invention.

[0030] Figure 3 is a process flow diagram of a quantum device manufacturing method according to a first embodiment of the present invention.

[0031] Figure 4 is a process cross-sectional view of a quantum device manufacturing method according to a first embodiment of the present invention.

[0032] Figure 5 is a process flow chart of a quantum device manufacturing method according to a second embodiment of the present invention.

[0033] Figure 6 is a cross-sectional view of a process for manufacturing a quantum device according to a second embodiment of the present invention.

[0034] Any specific structural or functional descriptions of embodiments according to the concept of the present invention disclosed in this specification are merely illustrative for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and are not limited to the embodiments described in this specification.

[0035] Embodiments according to the concept of the present invention may have various modifications and take various forms, and thus, embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, but rather includes all modifications, equivalents, or alternatives falling within the spirit and technical scope of the present invention.

[0036] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be construed in an idealized or overly formal sense unless explicitly defined herein.

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0038] FIG. 1 is a cross-sectional view of a quantum device according to an embodiment of the present invention, and FIG. 2 is a top view of a quantum device according to an embodiment of the present invention.

[0039] Referring to FIGS. 1 and 2, a quantum device according to an embodiment of the present invention comprises a substrate (10), a lower metal electrode (20), a graphene oxide layer (30), and an upper metal electrode (40).

[0040] The substrate (10) functions as a base on which components of a quantum device according to one embodiment of the present invention are formed.

[0041] The lower metal electrode (20) is formed on the substrate (10), and the upper metal electrode (40) is formed on the graphene oxide layer (30) described later.

[0042] For example, the lower metal electrode (20) and the upper metal electrode (40) described below may be composed of a material having high electrical conductivity, low work function, excellent oxidation resistance, and chemical stability.

[0043] For example, the lower metal electrode (20) and the upper metal electrode (40) may be superconductors. As a specific example, the lower metal electrode (20) and the upper metal electrode (40) may be made of a metal selected from aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or may be made of an alloy selected from a niobium-titanium alloy (NbTi), a niobium-tin alloy (NbSn), or may be made of barium-bismuth-oxide (BaBiO3). Since these materials have a relatively high superconducting transition temperature compared to other materials, their application to quantum devices is relatively easy compared to other materials.

[0044] The graphene oxide layer (30) is formed on the lower metal electrode (20) and is an insulating component.

[0045] For example, the thickness of the graphene oxide layer (30) may be configured to be 1 nm or more and 10 μm or less. The thickness of the graphene oxide layer (30) reflects the characteristics of the manufacturing process. Specifically, since the graphene deposited on the lower metal electrode (20) by the chemical vapor deposition (CVD) method has a thickness of about 1 nm, the lower limit of the thickness of the graphene oxide layer (30) is set to 1 nm. In addition, when the graphene oxide solution (34) in which graphene oxide powder is dissolved is coated on the lower metal electrode (20), the thickness can be up to 10 μm, and therefore the upper limit of the thickness of the graphene oxide layer (30) is set to 10 μm.

[0046] A quantum device according to an embodiment of the present invention has a MIM structure composed of metal-insulator-metal, and as described above, the metal corresponding to the lower metal electrode (20) and the upper metal electrode (40) is a superconductor such as aluminum (Al), niobium (Nb), tantalum (Ta), etc., and the insulator is a graphene oxide layer (30).

[0047] This MIM structure is one of the core components of quantum devices and plays a crucial role in determining the performance of quantum devices.

[0048] In a MIM structure, the metal serves as the electrical conductor of the quantum device, while the insulator forms the quantum domain. The quantum domain is the space where the unique energy levels of quantum atoms reside, determining the characteristics of the quantum device. This MIM structure can reduce the size of quantum devices, improve their performance, and simplify their manufacturing process.

[0049] For example, the lower metal electrode (20) and the upper metal electrode (40) can be configured to form a Josephson junction by the graphene oxide layer (30).

[0050] According to one embodiment of the present invention, two superconductors, a lower metal electrode (20) and an upper metal electrode (40), are connected by a graphene oxide layer (30) that is an insulator and has a thin thickness of 1 nm or more and 10 μm or less to form a Josephson junction.

[0051] The phenomenon of current flowing through a Josephson junction is called the Josephson Effect, and the principle of current flow through a Josephson junction is explained by the quantum tunneling effect. The quantum tunneling effect is a phenomenon in which particles overcome an energy barrier when moving from a higher energy level to a lower energy level.

[0052] In a quantum device according to an embodiment of the present invention, in the case of a Josephson junction, since the thickness of the graphene oxide layer (30), which is an insulator, is very thin, electrons can flow current through the tunneling effect through the graphene oxide layer (30), which is an insulator.

[0053] FIG. 3 is a process flow diagram of a quantum device manufacturing method according to a first embodiment of the present invention, and FIG. 4 is a process cross-sectional diagram of a quantum device manufacturing method according to a first embodiment of the present invention.

[0054] Referring to FIGS. 3 and 4, a method for manufacturing a quantum device according to a first embodiment of the present invention may be configured to include a lower metal electrode forming step (S10), a graphene layer deposition step (S22), a graphene layer oxidation step (S24), and an upper metal electrode forming step (S30).

[0055] Referring to FIGS. 3 and 4, in the lower metal electrode forming step (S10), a process of forming a lower metal electrode (20) on a substrate (10) is performed.

[0056] The substrate (10) functions as a base on which components of a quantum device according to an embodiment of the present invention are formed, and the lower metal electrode (20) and the upper metal electrode (40) described below may be composed of a material having high electrical conductivity, low work function, excellent oxidation resistance, and chemical stability. For example, the lower metal electrode (20) and the upper metal electrode (40) may be superconductors.

[0057] As a specific example, the lower metal electrode (20) and the upper metal electrode (40) may be made of a metal selected from among aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or may be made of an alloy selected from among a niobium-titanium alloy (NbTi), a niobium-tin alloy (NbSn), or may be made of barium-bismuth-oxide (BaBiO3). Since these materials have a relatively high superconducting transition temperature compared to other materials, their application to quantum devices is relatively easy compared to other materials.

[0058] For example, in the lower metal electrode formation step (S10), the lower metal electrode (20) can be formed on the graphene oxide layer (30) using metal etching or lift-off method.

[0059] In the graphene layer deposition step (S22), a process of depositing a graphene layer (32) on the lower metal electrode (20) is performed. For example, in the graphene layer deposition step (S22), the graphene layer (32) may be deposited on the lower metal electrode (20) using a chemical vapor deposition (CVD) method.

[0060] In the graphene layer oxidation step (S24), a process is performed in which the graphene layer (32) deposited on the lower electrode is exposed to oxygen radicals so that the oxygen radicals are adsorbed onto the graphene layer (32), thereby oxidizing the graphene layer (32) and forming a graphene oxide layer (30).

[0061] The graphene oxide layer (30) formed on the lower metal electrode (20) has insulating properties and its thickness may be 1 nm or more and 10 μm or less.

[0062] In the upper metal electrode forming step (S30), a process of forming an upper metal electrode (40) on the graphene oxide layer (30) is performed. For example, in the upper metal electrode forming step (S30), the upper metal electrode (40) can be formed on the graphene oxide layer (30) using metal etching or a lift-off method.

[0063] A quantum device manufactured by a method for manufacturing a quantum device according to an embodiment of the present invention has a MIM structure composed of metal-insulator-metal, and the metal corresponding to the lower metal electrode (20) and the upper metal electrode (40) is a superconductor such as aluminum (Al), niobium (Nb), tantalum (Ta), etc., and the insulator is a graphene oxide layer (30).

[0064] This MIM structure is one of the core components of quantum devices and plays a crucial role in determining the performance of quantum devices.

[0065] In a MIM structure, the metal serves as the electrical conductor of the quantum device, while the insulator forms the quantum domain. The quantum domain is the space where the unique energy levels of quantum atoms reside, determining the characteristics of the quantum device. This MIM structure can reduce the size of quantum devices, improve their performance, and simplify their manufacturing process.

[0066] For example, the lower metal electrode (20) and the upper metal electrode (40) can be configured to form a Josephson junction by the graphene oxide layer (30).

[0067] According to a quantum device manufactured by a method for manufacturing a quantum device according to an embodiment of the present invention, two superconducting lower metal electrodes (20) and upper metal electrodes (40) are connected by a graphene oxide layer (30) that is an insulator and has a thin thickness of 1 nm or more and 10 μm or less to form a Josephson junction.

[0068] The phenomenon of current flowing through a Josephson junction is called the Josephson Effect, and the principle of current flow through a Josephson junction is explained by the quantum tunneling effect. The quantum tunneling effect is a phenomenon in which particles overcome an energy barrier when moving from a higher energy level to a lower energy level.

[0069] In a quantum device according to an embodiment of the present invention, in the case of a Josephson junction, since the thickness of the graphene oxide layer (30), which is an insulator, is very thin, electrons can flow current through the tunneling effect through the graphene oxide layer (30), which is an insulator.

[0070] FIG. 5 is a process flow diagram of a quantum device manufacturing method according to a second embodiment of the present invention, and FIG. 6 is a process cross-sectional diagram of a quantum device manufacturing method according to a second embodiment of the present invention.

[0071] Referring to FIGS. 5 and 6, a method for manufacturing a quantum device according to a second embodiment of the present invention may be configured to include a lower metal electrode forming step (S10), a graphene oxide coating step (S26), a graphene oxide reduction step (S28), and an upper metal electrode forming step (S30).

[0072] Below, the second embodiment is described with a focus on the differences from the first embodiment.

[0073] In the lower metal electrode formation step (S10), a process of forming a lower metal electrode (20) on a substrate (10) is performed.

[0074] In the graphene oxide coating step (S26), a process of coating a graphene oxide solution (34) on the lower metal electrode (20) is performed.

[0075] In the graphene oxide reduction step (S28), a process of forming a graphene oxide layer (30) on the lower metal electrode (20) is performed by reducing the graphene oxide solution (34) coated on the lower metal electrode (20) using a chemical reduction method or a thermal reduction method.

[0076] The chemical reduction method is a method of reducing the graphene oxide solution (34) by coating the graphene oxide solution (34) on the lower metal electrode (20) and then adding a reducing agent. Hydrogen peroxide, zinc chloride, iron chloride, etc. can be used as the reducing agent.

[0077] The thermal reduction method is a method of reducing graphene oxide by coating a graphene oxide solution (34) on a lower metal electrode (20) and then applying heat. The heat treatment temperature may be 100°C or higher and 200°C or lower.

[0078] In the upper metal electrode formation step (S30), a process of forming an upper metal electrode (40) on a graphene oxide layer (30) is performed.

[0079] As described in detail above, according to the present invention, there is provided a quantum device and a method for manufacturing the same, which can prevent problems of thickness consistency that occur in the manufacturing of an insulating layer of a quantum device using a conventional metal oxide film, and thereby reduce the consistency of the quantum tunneling effect and the performance of the entire quantum device.

[0080] In addition, by applying graphene oxide, which has insulating properties, to the insulating layer of the quantum device, a consistent and low thickness can be maintained compared to an insulating layer using a conventional metal oxide film, and during the manufacturing process, the thickness and quality of the insulating layer can be optimized by forming the graphene oxide layer in a manner compatible with the existing semiconductor process.

[0081] Additionally, the application of graphene oxide has the effect of improving the consistency of the quantum tunneling effect, which can improve the overall performance of the quantum device.

[0082] In addition, compared to conventional metal oxide films, graphene oxide has the property of maintaining a more uniform and thinner thickness, which can significantly reduce the defect rate in the manufacturing process of quantum devices and shorten the manufacturing time. This improved manufacturing efficiency can lead to a reduction in production costs, which can have the effect of bringing about economic benefits.

[0083] [Explanation of symbols]

[0084] 10: Substrate

[0085] 20: Lower metal electrode

[0086] 30: Graphene oxide layer

[0087] 32: Graphene layer

[0088] 34: Graphene oxide solution

[0089] 40: Upper metal electrode

[0090] S10: Lower metal electrode formation step

[0091] S22: Graphene layer deposition step

[0092] S24: Graphene layer oxidation step

[0093] S26: Graphene oxide coating step

[0094] S28: Graphene oxide reduction step

[0095] S30: Upper metal electrode formation step

Claims

1. As a quantum device, substrate; A lower metal electrode formed on the substrate; A graphene oxide layer formed on the lower metal electrode and having insulating properties; and A quantum device comprising an upper metal electrode formed on the graphene oxide layer.

2. In paragraph 1, A quantum device, characterized in that the thickness of the graphene oxide layer is 10㎛ or less.

3. In paragraph 2, A quantum device, characterized in that the thickness of the graphene oxide layer is 1 nm or more.

4. In paragraph 3, A quantum device, characterized in that the lower metal electrode and the upper metal electrode are superconductors.

5. In paragraph 4, A quantum device, characterized in that the lower metal electrode and the upper metal electrode form a Josephson junction by the graphene oxide layer.

6. In paragraph 3, The lower metal electrode and the upper metal electrode are made of a metal selected from aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or an alloy selected from a niobium-titanium alloy (NbTi), a niobium-tin alloy (NbSn), or barium-bismuth-oxide (BaBiO). 3 ) is characterized by being composed of a quantum device.

7. A method for manufacturing a quantum device, A lower metal electrode forming step of forming a lower metal electrode on a substrate; A graphene layer deposition step of depositing a graphene layer on the lower metal electrode; A graphene layer oxidation step of exposing a graphene layer deposited on the lower electrode to oxygen radicals and oxidizing the graphene layer by adsorbing the oxygen radicals onto the graphene layer to form a graphene oxide layer; and A method for manufacturing a quantum device, comprising an upper metal electrode forming step of forming an upper metal electrode on the graphene oxide layer.

8. A method for manufacturing a quantum device, A lower metal electrode forming step of forming a lower metal electrode on a substrate; A graphene oxide coating step of coating a graphene oxide solution on the lower metal electrode; A graphene oxide reduction step for forming a graphene oxide layer on the lower metal electrode by reducing the graphene oxide solution coated on the lower metal electrode using a chemical reduction method or a thermal reduction method; and A method for manufacturing a quantum device, comprising an upper metal electrode forming step of forming an upper metal electrode on the graphene oxide layer.

9. In paragraph 7 or 8, A method for manufacturing a quantum device, characterized in that at least one of the lower metal electrode forming step and the upper metal electrode forming step uses a metal etching or lift-off method.

10. In paragraph 7 or 8, A method for manufacturing a quantum device, characterized in that the thickness of the graphene oxide layer is 10㎛ or less.

11. In paragraph 10, A method for manufacturing a quantum device, characterized in that the thickness of the graphene oxide layer is 1 nm or more.

12. In paragraph 11, A method for manufacturing a quantum device, characterized in that the lower metal electrode and the upper metal electrode are superconductors.

13. In paragraph 12, A method for manufacturing a quantum device, characterized in that the lower metal electrode and the upper metal electrode form a Josephson junction by the graphene oxide layer.

14. In paragraph 12, The lower metal electrode and the upper metal electrode are made of a metal selected from aluminum (Al), niobium (Nb), tantalum (Ta), lead (Pb), and tin (Sn), or an alloy selected from a niobium-titanium alloy (NbTi), a niobium-tin alloy (NbSn), or barium-bismuth-oxide (BaBiO). 3 ) characterized by comprising a quantum device manufacturing method.

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