WO2021241356A1 - Nanogap electrode structure, method for manufacturing same, analysis device and analysis method - Google Patents

Abstract

Provided are a nanogap electrode structure that enables stable formation of a nanogap by an easy way, a method for manufacturing the same, an analysis device and an analysis method. The nanogap electrode structure 10 comprises an insulating film 11 that has a nanopore 13, said nanopore allowing the passage of a sample therethrough, and a nanogap electrode 12 that is formed on the insulating film 11 and provided with a nanogap 17 between a pair of electrode parts 14a and 14b. The pair of electrode parts 14a and 14b have an above-nanopore region 15 that is positioned above the nanopore 13, and a connection region 16 that is positioned above the insulating film 11 and connected to the above-nanopore region 15. The nanogap 17 is formed within the above-nanopore region 15.

Description

Nanogap electrode structure, its manufacturing method, analyzer, analysis method

The present invention relates to a nanogap electrode structure, a manufacturing method thereof, an analyzer, and an analysis method.

In recent years, nanogap electrodes having nanogap between facing electrodes have been attracting attention, and research on electronic devices and biodevices using nanogap electrodes has been actively conducted. In the field of biodevices, for example, a single-stranded DNA (deoxyribonucleic acid) is passed through a nanogap, and the tunnel current flowing between electrodes when the base of the single-stranded DNA passes through the nanogap is measured and the current is measured. An analyzer that identifies the bases constituting single-stranded DNA based on the value has been developed.

As a method for forming a nanogap electrode, a mechanically controllable break junction (MCBJ) system is known (see, for example, Patent Document 1).

Special Table 2019-525766 Gazette

However, the MCBJ system as described in Patent Document 1 requires a mechanism for applying mechanical stress in order to form a nanogap, and it is desired to stably form a nanogap by a simple method. It is rare.

An object of the present invention is to provide a nanogap electrode structure capable of stably forming a nanogap by a simple method, and a method for manufacturing the same, an analyzer, and an analysis method.

The nanogap electrode structure of the present invention includes an insulating film having nanopores through which a sample passes, and a nanogap electrode provided on the insulating film and having a nanogap between a pair of electrode portions, and the pair of electrodes. The portion has a nanopore upper region located above the nanopore and a connection region located above the insulating film and connected to the nanopore upper region, and the nanogap is provided in the nanopore upper region. Has been done.

The method for manufacturing a nanogap electrode structure of the present invention is a preparatory step for preparing a nanogap electrode provided on an insulating film having nanopores and composed of a pair of electrode portions having a nanopore upper region located above the nanopores. And a nanogap forming step of applying a voltage between the pair of electrode portions and forming a nanogap in the nanopore upper region by electromigration.

The analyzer of the present invention includes the nanogap electrode structure, a power supply that applies a voltage between the pair of electrode portions, a current meter that detects a tunnel current flowing between the pair of electrode portions, and the tunnel. It is equipped with an analysis unit that analyzes the sample based on the current value of the current.

The analysis method of the present invention comprises a first step of forming a nanogap in a nanogap electrode provided on an insulating film having nanopores and composed of a pair of electrode portions having a nanopore upper region located above the nanopores. The second step is to detect the tunnel current when the sample passes through the nanogap and analyze the sample based on the current value of the tunnel current.

According to the present invention, it is possible to stably form a nanogap in the nanopore upper region located above the nanopore in the pair of electrode portions by a simple method.

In addition, since nanogap is formed on the nanopore, the sample to be analyzed can be efficiently guided to the nanogap.

It is a perspective view which shows the appearance of the nanogap electrode structure which concerns on 1st Embodiment. It is an enlarged view around the nanopore shown by the symbol II in FIG. 1. It is an enlarged view around the nanopore of a nanogap electrode structure in a state where a pair of electrode portions is not cut. It is a top view for demonstrating the insulating film forming process. 4 is a cross-sectional view taken along the line BB of FIG. 4A. It is a top view for demonstrating the nanopore formation process. FIG. 5 is a cross-sectional view taken along the line BB of FIG. 5A. It is a top view for demonstrating the nanopore embedding process. 6 is a cross-sectional view taken along the line BB of FIG. 6A. It is a top view for demonstrating the electrode formation process. FIG. 7 is a cross-sectional view taken along the line BB of FIG. 7A. It is a top view for demonstrating the flow path formation process. FIG. 8 is a cross-sectional view taken along the line BB of FIG. 8A. It is a top view for demonstrating the nanogap formation process. 9 is a cross-sectional view taken along the line BB of FIG. 9A. It is explanatory drawing for demonstrating the analyzer which concerns on 1st Embodiment. It is an enlarged view around the nanopore of the nanogap electrode structure which concerns on 2nd Embodiment. It is an enlarged view which shows the state which the 1st electrode part and the 2nd electrode part of the nanogap electrode structure which concerns on 2nd Embodiment are not cut. It is explanatory drawing for demonstrating the deformation example of a thin-walled portion. It is an enlarged view around the nanopore of the nanogap electrode structure which concerns on 3rd Embodiment. It is an enlarged view which shows the state which the 1st electrode part and the 2nd electrode part of the nanogap electrode structure which concerns on 3rd Embodiment are not cut. It is sectional drawing of the nanogap electrode structure which concerns on 4th Embodiment. It is a top view for demonstrating the adhesive layer formation process. FIG. 11 is a cross-sectional view taken along the line BB of FIG. 17A. It is a top view for demonstrating the electrode formation process. FIG. 8 is a cross-sectional view taken along the line BB of FIG. 18A. It is a top view for demonstrating the adhesive layer removal process. 19A is a cross-sectional view taken along the line BB of FIG. 19A. It is a top view for demonstrating the adhesive layer formation process. 20A is a cross-sectional view taken along the line BB of FIG. 20A. It is a top view for demonstrating the nanopore formation process. FIG. 21 is a cross-sectional view taken along the line BB of FIG. 21A. It is an enlarged view around the nanopore of the nanogap electrode structure which concerns on 5th Embodiment. It is an enlarged view which shows the state which the 1st electrode part and the 2nd electrode part of the nanogap electrode structure which concerns on 5th Embodiment are not cut. It is a top view for demonstrating the 1st layer formation process. FIG. 2 is a cross-sectional view taken along the line BB of FIG. 24A. It is a top view for demonstrating the 2nd layer formation process. FIG. 5 is a cross-sectional view taken along the line BB of FIG. 25A. It is a top view for demonstrating the flow path formation process. FIG. 6 is a cross-sectional view taken along the line BB of FIG. 26A.

[First Embodiment]
FIG. 1 is a perspective view showing the appearance of the nanogap electrode structure 10 according to the first embodiment. In FIG. 1, the X-axis, the Y-axis, and the Z-axis indicate the three axes of the Cartesian coordinate system. The Z-axis direction is the direction of the thickness of the nanogap electrode structure 10 (thickness direction). The Y-axis direction is the width direction (width direction) of the nanogap electrode structure 10. The X-axis direction is the direction in which the current described later flows. The positive direction of the Z axis is the upward direction, and the negative direction of the Z axis is the downward direction. In each member constituting the nanogap electrode structure 10, the upper surface is the front surface and the lower surface is the back surface. Viewing the nanogap electrode structure 10 from top to bottom is referred to as "planar view".

As shown in FIG. 1, the nanogap electrode structure 10 includes an insulating film 11 and a nanogap electrode 12 provided on the insulating film 11. The insulating film 11 has a nanopore 13 through which the sample passes. The nanogap electrode 12 is composed of a pair of electrode portions 14a and 14b to which a voltage is applied. The pair of electrode portions 14a and 14b have a nanopore upper region 15 located above the nanopore 13 and a connection region 16 located above the insulating film 11 and connected to the nanopore upper region 15. In the present embodiment, the nanopore upper region 15 is arranged so as to block a part of the nanopore 13, but it may be arranged so as to block the entire nanopore 13. As will be described in detail later, the nanopore upper region 15 is configured to induce disconnection due to electromigration by the current flowing when a voltage is applied between the pair of electrode portions 14a and 14b in a state of being connected to each other. There is. Due to the disconnection occurring in the nanopore upper region 15, a nanogap 17 connected to the nanopore 13 is formed between the pair of electrode portions 14a and 14b. FIG. 1 shows a nanogap electrode structure 10 in which a nanogap 17 is formed between a pair of electrode portions 14a and 14b and the pair of electrode portions 14a and 14b are not connected to each other. In the following description, when the pair of electrode portions 14a and 14b will be described separately, they will be described as the first electrode portion 14a and the second electrode portion 14b.

The configuration of the nanogap electrode structure 10 will be described in detail with reference to FIGS. 1 and 2. The outer shape of the nanogap electrode structure 10 in a plan view is not particularly limited, and is a quadrangle in the present embodiment.

The insulating film 11 is formed of, for example, a SiN film (silicon nitride film), a SiO film (silicon oxide film), or the like. The insulating film 11 is formed of a SiN film in this embodiment. The thickness of the insulating film 11 is not particularly limited, and is 100 nm in this embodiment.

The insulating film 11 is provided on the substrate 18. The substrate 18 is a silicon substrate having a plane orientation of (100) in the present embodiment, but the substrate 18 is not limited to this. The thickness of the substrate 18 is not particularly limited, and is 775 μm in this embodiment. A flow path 19 is provided inside the substrate 18. In FIG. 1, the flow path 19 is shown by a two-dot chain line. The flow path 19 penetrates the substrate 18 in the thickness direction and connects to the nanopore 13. Further, the flow path 19 is connected to the nanogap 17 via the nanopore 13. The shape of the flow path 19 is not particularly limited and may be any shape. In the present embodiment, the shape of the flow path 19 is a quadrangular pyramid shape, and the area of the cross section parallel to the XY plane is increased from top to bottom.

The nanopore 13 penetrates the insulating film 11 in the thickness direction. The diameter of the nanopore 13 is several nm to several hundred nm, and in this embodiment, it is 100 nm.

Gold (Au), platinum (Pt), or the like is used as the material of the nanogap electrode 12, and in this embodiment, it is gold. The nanogap electrode 12 has a single-layer structure in this example, but may have a laminated structure in which two or more layers are laminated. When the nanogap electrode 12 has a laminated structure, each layer may be formed of the same material or a different material. When each layer is formed of different materials, the above materials can be used in combination.

The outer shape of the first electrode portion 14a and the second electrode portion 14b in a plan view is not particularly limited, but the shape in which the nanopore upper region 15 is thinner than the connection region 16 is preferable, and the vicinity of the center of the nanopore upper region 15 is the thinnest. The shape is particularly preferred. In the present embodiment, the outer shapes of the first electrode portion 14a and the second electrode portion 14b in a plan view are areosceles triangles, respectively, and their apex angles are arranged near the center of the nanopore upper region 15. .. As a result, the width (length in the Y-axis direction) of the nanogap electrode 12 becomes smaller toward the center of the nanopore 13. The minimum width of the first electrode portion 14a and the second electrode portion 14b is, for example, 1 nm to 100 nm. In FIG. 1, the first electrode portion 14a and the second electrode portion 14b are arranged in the X-axis direction with their apex angles facing each other. When a voltage is applied to the pair of electrode portions 14a and 14b, a current flows in the X-axis direction. The thickness of the pair of electrode portions 14a and 14b is 30 nm in this embodiment.

FIG. 2 is an enlarged view of the vicinity of nanopore 13 indicated by reference numeral II in FIG. In FIG. 2, the boundary between the nanopore upper region 15 and the connecting region 16 is shown by a alternate long and short dash line. The nanopore upper region 15 and the connection region 16 are provided in the first electrode portion 14a and the second electrode portion 14b, respectively. When the nanopore upper region 15 is described separately in the following description, the nanopore upper region provided in the first electrode portion 14a is described as the first nanopore upper region 15a and is provided in the second electrode portion 14b. The nanopore upper region is referred to as a second nanopore upper region 15b. Further, when the connection region 16 is described separately, the connection region provided in the first electrode portion 14a is described as the first connection region 16a, and the connection region provided in the second electrode portion 14b is referred to as the first connection region. It is described as the connection area 16b of 2.

The nanogap 17 is provided between the pair of electrode portions 14a and 14b. The spacing between the nanogap 17 is about one atomic layer, for example, 0.1 nm to 0.3 nm. In FIG. 2, the nanogap 17 is provided near the center of the nanopore upper region 15.

FIG. 3 shows a nanogap electrode structure 10 in a state where the pair of electrode portions 14a and 14b are not cut. The nanopore upper region 15 is configured to induce disconnection due to electromigration by a current flowing when a voltage is applied between a pair of electrode portions 14a and 14b in a state of being connected to each other, and an EM disconnection inducing portion. Has the function as. In this embodiment, the minimum width (length in the Y-axis direction) of the nanopore upper region 15 is smaller than the minimum width of the connection region 16. The thickness of the nanopore upper region 15 (length in the Z-axis direction) and the thickness of the connecting region 16 are the same. Therefore, in the plane (YZ plane) orthogonal to the direction in which the current flows between the pair of electrode portions 14a and 14b (X-axis direction), the minimum value of the cross-sectional area of the nanopore upper region 15 is the cross-sectional area of the connection region 16. Less than the minimum. The smaller the cross-sectional area in the plane orthogonal to the direction in which the current flows between the pair of electrode portions 14a and 14b, the higher the current density and the more likely the disconnection due to electromigration occurs.

In the nanogap electrode structure 10 in which the pair of electrode portions 14a and 14b are not cut, electromigration occurs due to the current flowing when a voltage is applied between the pair of electrode portions 14a and 14b. In the process of diffusion and / or movement of metal atoms in the nanopore upper region 15 by electromigration, the first electrode portion 14a and the second electrode portion 14b are cut at a portion where the current density of the nanopore upper region 15 is large, and the nanopore is formed. A nanogap 17 is formed in the upper region 15 (see FIG. 2).

In the nanogap electrode structure 10, a process in which metal atoms in the nanopore upper region 15 are diffused and / or moved after a predetermined time has elapsed (for example, 15 minutes) after the application of the voltage that causes electromigration is stopped. The nanogap 17 is filled with, and the first electrode portion 14a and the second electrode portion 14b are reconnected. In the nanogap electrode structure 10 in which the first electrode portion 14a and the second electrode portion 14b are not cut in this way, a voltage is applied between the pair of electrode portions 14a and 14b, and electromigration occurs again. As a result, a nanogap 17 is formed in the nanopore upper region 15 where the current density is high (see FIG. 2).

The nanogap electrode structure 10 is configured such that, of the pair of electrode portions 14a and 14b, the nanopore upper region 15 located above the nanopore 13 induces disconnection due to electromigration. When a voltage is applied between the pair of electrode portions 14a and 14b in a state of being connected to each other, the connection region 16 located at the upper part of the insulating film 11 does not cause disconnection due to electromigration and has the highest current density. Since the disconnection occurs due to electromigration in the vicinity of the nanopore upper region 15, the nanogap 17 connected to the nanopore 13 can be formed. Therefore, the nanogap electrode structure 10 can stably form the nanogap 17 by a simple method.

Next, a method for manufacturing the nanogap electrode structure will be described. The method for manufacturing the nanogap electrode structure is a nanogap electrode provided on an insulating film having nanopores, and a nanogap electrode composed of a pair of electrode portions having a nanopore upper region located above the nanopores is prepared. It has a preparatory step for forming a nanogap and a nanogap forming step for forming a nanogap in the nanopore upper region by electromigration by applying a voltage between a pair of electrode portions.

A method for manufacturing the nanogap electrode structure 10 according to the present embodiment will be described with reference to FIGS. 4A and 4B to 9A and 9B. 4A to 9A are plan views, and FIGS. 4B to 9B are cross-sectional views taken along the line BB of FIGS. 4A to 9A. In the present embodiment, the outer shape in a plan view is a square, but in FIGS. 4A to 9A, only a part of the outer shape is shown.

First, the preparation process will be described with reference to FIGS. 4A and 4B to 8A and 8B. The preparatory step includes an insulating film forming step, a nanopore forming step, a nanopore embedding step, an electrode layer forming step, and a flow path forming step.

As shown in FIGS. 4A and 4B, the insulating film forming step forms the insulating film 21 on the substrate 20. The substrate 20 is a silicon substrate having a thickness of 775 μm and a plane orientation of (100). The insulating film 21 is formed by, for example, a CVD (Chemical Vapor Deposition) method using DCS (dichlorosilane) as a raw material gas. In the present embodiment, the insulating film 21 is formed only on the surface of the substrate 20, but the insulating films 21 may be formed on both sides of the substrate 20.

As shown in FIGS. 5A and 5B, the nanopore forming step forms the nanopore 23 on the insulating film 21. First, a photoresist is applied to the insulating film 21 to form a photoresist layer (not shown), and the photoresist layer is patterned by a photolithography technique. A resist pattern is formed in the photoresist layer in which a portion corresponding to the nanopore 23 is opened. Next, the insulating film 21 is dry-etched using the photoresist layer on which the resist pattern is formed as a mask. As a result, the nanopore 23 is formed on the insulating film 21.

As shown in FIGS. 6A and 6B, the nanopore embedding step forms a deposit film 27 on the nanopore 23. First, a SiO film is formed on the entire surface of the insulating film 21 by a CVD method using, for example, TEOS (tetraexisilane) as a raw material gas. Next, for example, the surface of the SiO film is flattened by a CMP (Chemical Mechanical Polishing) method. The flattening is preferably performed so that the surface of the insulating film 21 is exposed. The flattening removes the SiO film on the surface of the insulating film 21. The deposit film 27 is formed by the SiO film remaining in the nanopore 23. The deposit film 27 may be an a-Si film (amorphous silicon film) or the like. The flattening may be performed by etching back the surface of the deposit film 27 instead of using the CMP method.

As shown in FIGS. 7A and 7B, in the electrode forming step, the nanogap electrode 22 is formed on the insulating film 21. First, a photoresist is applied to the insulating film 21 to form a photoresist layer (not shown), and the photoresist layer is patterned by a photolithography technique to form a nanogap electrode 22 in the insulating film 21. Is exposed, and the portion where the nanogap electrode 22 is not formed is covered with a photoresist layer. Next, an Au film is formed on the photoresist layer and on the exposed insulating film 21 by performing a sputtering method using Au as the target material. Next, the Au film on the photoresist layer is removed together with the photoresist layer by performing a lift-off method. The nanogap electrode 22 is formed by the Au film remaining on the insulating film 21. The Au film may be formed by using a vapor deposition method. When the adhesiveness between the Au film and the insulating film 21 is poor, an adhesive layer such as titanium (Ti) or chromium (Cr) may be provided between the Au film and the insulating film 21. The thickness of the adhesive layer is, for example, about 2 nm.

The electrode forming step is not limited to the case where the above lift-off method is performed. For example, when Pt is used as a material for forming the nanogap electrode 22, a Pt film is formed on the insulating film 21 by a sputtering method using Pt as a target material, and a photoresist is applied to the photoresist to form a photoresist. A layer is formed, the photoresist layer is patterned by a photolithography technique, and the Pt film is dry-etched using the patterned photoresist layer as a mask. The nanogap electrode 22 can be formed from the Pt film remaining on the insulating film 21.

The nanogap electrode 22 is composed of a pair of electrode portions 24a and 24b (first electrode portion 24a and second electrode portion 24b) to which a voltage is applied. The pair of electrode portions 24a and 24b are located above the nanopore 23 and the nanopore upper region 25 (first nanopore upper region 25a, second nanopore upper region 25b) and above the insulating film 21 and are located above the nanopore. It has a connection area 26 (first connection area 26a, second connection area 26b) connected to the area 25. In the electrode forming step, the nanogap electrode 22 is formed so that the outer shapes of the first electrode portion 24a and the second electrode portion 24b are isosceles triangles in a plan view. The first electrode portion 24a and the second electrode portion 24b are connected in the vicinity of the apex of each isosceles triangle. The portion where the first electrode portion 24a and the second electrode portion 24b are connected is included in the nanopore upper region 25. The width (length in the Y-axis direction) of the portion where the first electrode portion 24a and the second electrode portion 24b are connected is, for example, 1 nm to 100 nm, which is the minimum value of the width of the entire nanogap electrode 22. be. As a result, the minimum width of the nanopore upper region 25 becomes smaller than the minimum width of the connection region 26. Since the thickness of the first electrode portion 24a (length in the Z-axis direction) and the thickness of the second electrode portion 24b are the same, the minimum value of the cross-sectional area of the nanopore upper region 25 in the YZ plane is the connection region 26. Less than the minimum cross-sectional area of. As described above, the nanopore upper region 25 is configured to induce disconnection due to electromigration by the current flowing when a voltage is applied between the pair of electrode portions 24a and 24b, and functions as an EM disconnection inducing portion. Has.

As shown in FIGS. 8A and 8B, the flow path forming step forms a flow path 29 connected to the nanopore 23 on the substrate 20. First, a protective film (not shown) is formed on the front surface of the insulating film 21, the surface of the nanogap electrode 22, and the back surface of the substrate 20. The protective film is preferably a material having a large etching rate selectivity with respect to the wet etching solution in anisotropic wet etching described later. The protective film is, for example, a SiO film formed by a CVD method using TEOS as a raw material gas. Next, a photoresist layer (not shown) is formed on a protective film provided on the back surface of the substrate 20, and the photoresist layer is patterned by photolithography technology. The photoresist layer on which the resist pattern is formed is used as a mask on the back surface of the substrate 20. Dry etch the protective film. As a result, an opening is formed in the portion of the protective film provided on the back surface of the substrate 20 corresponding to the flow path 29. The back surface of the substrate 20 is exposed from the opening of the protective film. Next, the substrate 20 is immersed in a wet etching solution to perform anisotropic wet etching. As the wet etching solution, an alkaline aqueous solution such as KOH (potassium hydroxide) or TMAH (tetramethylammonium hydroxide) is used. The protective film functions as a mask for anisotropic wet etching. Therefore, only a part of the back surface of the substrate 20 exposed from the opening of the protective film is etched. After forming the flow path 29 on the substrate 20, the protective film and the deposit film 27, which are SiO films, are removed by wet etching using, for example, HF (hydrofluoric acid) as a wet etching solution. As a result, the nanogap electrode structure precursor 30 shown in FIGS. 8A and 8B is obtained.

As described above, the nanogap electrode structure precursor 30 can be manufactured by an insulating film forming step, a nanopore forming step, a nanopore embedding step, an electrode layer forming step, and a flow path forming step. The nanogap electrode structure precursor 30 has the same configuration as the nanogap electrode structure 10 except that it does not have the nanogap 17.

Next, the nanogap forming step will be described with reference to FIGS. 9A and 9B. First, the pair of electrode portions 24a and 24b of the nanogap electrode structure precursor 30 and the power supply 31 are electrically connected by using the wiring 35. In FIG. 9A, the wiring 35 and the power supply 31 are not shown. The power supply 31 is turned on, and a voltage is applied between the pair of electrode portions 24a and 24b. Since the cross-sectional area of the nanopore upper region 25 is smaller than that of the connection region 26, the current density is higher than that of the connection region 26, and disconnection occurs due to electromigration. When the nanopore upper region 25 is disconnected, the first electrode portion 24a and the second electrode portion 24b are cut off, and a nanogap 17 is formed in the nanopore upper region 25. The nanogap electrode structure precursor 30 on which the nanogap 17 is formed becomes the nanogap electrode structure 10 (see FIG. 1).

As shown in FIG. 10, the nanogap electrode structure 10 is used in an analyzer 40 that analyzes a small amount of sample. The analyzer 40 analyzes the sample by detecting a change in the tunnel current flowing between the pair of electrode portions 14a and 14b when the sample passes through the nanogap 17 of the nanogap electrode structure 10. Examples of the sample include DNA, protein, pollen, virus, cell, organic particle or inorganic particle, particulate matter such as PM (Particulate Matter) 2.5 and the like. The sample is dispersed in a solution containing an electrolyte, and the obtained sample solution is provided to the analyzer 40. Examples of the solution for dispersing the sample include Phosphate Buffered Saline (PBS) and the like.

The analyzer 40 includes a nanogap electrode structure 10, a power supply 41, a control unit 42, an ammeter 43, and an analysis unit 44. The nanogap electrode 12, the power supply 41, and the ammeter 43 of the nanogap electrode structure 10 are connected by using the wiring 45.

The power supply 41 is electrically connected to the pair of electrode portions 14a and 14b. The power supply 41 applies a voltage between the pair of electrode portions 14a and 14b. The voltage of the power supply 41 is controlled by the control unit 42.

The control unit 42 is electrically connected to the power supply 41. The control unit 42 sets the voltage of the power supply 41 to the first voltage, first controls to form a nanogap 17 between the pair of electrode units 14a and 14b, and sets the voltage of the power supply 41 to the first voltage. Is set to a different second voltage, and performs the second control of generating a tunnel current between the pair of electrode portions 14a and 14b facing each other via the nanogap 17.

The first control is performed in a state where the first electrode portion 14a and the second electrode portion 14b are not cut off. The second control is performed in a state where the nanogap 17 is formed between the pair of electrode portions 14a and 14b. The control unit 42 is configured to enable switching between the first control and the second control by, for example, operating an operation unit (not shown).

The ammeter 43 is electrically connected to the pair of electrode portions 14a and 14b. The ammeter 43 detects the tunnel current flowing between the pair of electrode portions 14a and 14b facing each other via the nanogap 17 when the second control is performed by the control unit 42. The ammeter 43 may detect the current flowing between the pair of electrode units 14a and 14b connected to each other when the first control is performed by the control unit 42.

The analysis unit 44 is electrically connected to the ammeter 43. The analysis unit 44 analyzes the sample based on the current value of the tunnel current detected by the ammeter 43. The current value of the tunnel current changes according to the electrical resistance of the sample passing through the nanogap 17. Therefore, for example, when the single-stranded DNA passes through the nanogap 17, the analysis unit 44 identifies the base based on the current value of the tunnel current that changes depending on the type of the base constituting the single-stranded DNA. It is possible to analyze the base sequence and the like.

Although not shown, the analyzer 40 may include a pair of electrodes for performing electrophoresis of a sample and a power source for applying a voltage to the pair of electrodes. By applying a voltage from the power source to the pair of electrodes, the sample is electrophoresed and the sample passes through the nanogap 17 and the nanopore 13. The sample may be configured to flow by pressure, or the sample may be configured to flow by using electrophoresis and pressure in combination.

The analyzer 40 applies a first voltage between the pair of electrode portions 14a and 14b to form a nanogap 17 in the nanopore upper region 15, and subsequently applies a second voltage between the pair of electrode portions 14a and 14b. The sample is analyzed by applying the voltage and detecting the tunnel current when the sample passes through the nanogap 17. Therefore, the analyzer 40 can continuously form the nanogap 17 and analyze the sample.

The nanogap electrode structure precursor 30 may be provided in the analyzer 40. The nanogap electrode structure 10 can be obtained by applying a voltage between the pair of electrode portions 24a and 24b to form the nanogap 17 in the nanopore upper region 25.

Next, the analysis method will be explained. The analysis method is a first nanogap electrode provided on an insulating film having nanopores, in which a nanogap is formed in a nanogap electrode composed of a pair of electrode portions having a nanopore upper region located above the nanopores. A second step of detecting the tunnel current when the sample passes through the nanogap and analyzing the sample based on the current value of the tunnel current. In this embodiment, an analysis method using the analyzer 40 will be described.

In the first step, first, the nanogap electrode structure 10 in a state where the first electrode portion 14a and the second electrode portion 14b are not cut is provided to the analyzer 40. The control unit 42 performs the first control for setting the voltage of the power supply 41 to the first voltage. Electromigration is generated by the current flowing due to the application of the first voltage between the pair of electrode portions 14a and 14b, and the nanogap 17 is formed in the nanopore upper region 15. As described above, in the analysis method according to the present embodiment, the nanogap 17 can be stably formed by a simple method.

In the second step, the control unit 42 performs the second control of setting the voltage of the power supply 41 to the second voltage. By applying a second voltage between the pair of electrode portions 14a and 14b, a tunnel current is generated between the pair of electrode portions 14a and 14b facing each other via the nanogap 17. The ammeter 43 detects the tunnel current. The analysis unit 44 analyzes the sample based on the current value of the tunnel current detected by the ammeter 43 when the sample passes through the nanogap 17. Since the nanogap 17 is formed on the nanopore 13, the sample to be analyzed can be efficiently guided to the nanogap.

[Second Embodiment]
FIG. 11 is an enlarged view of the vicinity of the nanopore 13 of the nanogap electrode structure 50 according to the second embodiment. In the following description, the same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The nanogap electrode structure 50 includes an insulating film 11 and a nanogap electrode 52 provided on the insulating film 11. The nanogap electrode 52 has a pair of electrode portions 54a and 54b. The pair of electrode portions 54a and 54b are located above the nanopore 13 and the nanopore upper region 55 (first nanopore upper region 55a, second nanopore upper region 55b) and above the insulating film 11 and are located above the nanopore. It has a connection area 56 (first connection area 56a, second connection area 56b) to be connected to the area 55. The nanopore upper region 55 is provided with a nanogap 17 that connects to the nanopore 13.

Similar to the nanogap electrode 12 according to the first embodiment, the nanogap electrode 52 has a smaller width (length in the Y-axis direction) toward the center of the nanopore 13. The nanogap electrode 52 is different from the nanogap electrode 12 in that it has a thin portion 57 in the vicinity of the nanopore 13. The thin portion 57 is a portion in which at least one of the front surface and the back surface of the nanogap electrode 52 is recessed, and in FIG. 11, a portion in which the back surface of the nanogap electrode 52 is recessed. The thin portion 57 has a smaller thickness (length in the Z-axis direction) than other portions of the nanogap electrode 52. The thin portion 57 is provided at least in the nanopore upper region 55, and in FIG. 11, it is provided in the entire nanopore upper region 55 and a part of the connection region 56. Further, the thin-walled portion 57 shown in FIG. 11 has a shape in which the side surface is recessed in addition to the back surface of the nanogap electrode 52, and the width (length in the Y-axis direction) is smaller than that of other portions in the nanogap electrode 52. ..

As described above, the nanogap electrode 52 has a smaller width toward the center of the nanopore 13 and has a thin portion 57 in the vicinity of the nanopore 13. Therefore, in the plane (YZ plane) orthogonal to the direction in which the current flows between the pair of electrode portions 54a and 54b (X-axis direction), the minimum cross-sectional area of the nanopore upper region 55 is the cross-sectional area of the connection region 56. Less than the minimum value of. In the nanopore upper region 55 having a thickness smaller than the connection region 56, the current density is higher than that in the connection region 56, and disconnection due to electromigration is more likely to occur, so that the nanogap 17 is surely formed.

FIG. 12 is an enlarged view showing a state in which the first electrode portion 54a and the second electrode portion 54b of the nanogap electrode structure 50 are not cut. By applying a voltage between the pair of electrode portions 54a and 54b connected to each other, it is possible to generate a disconnection due to electromigration in the nanopore upper region 55 and form a nanogap 17 in the nanopore upper region 55 (Fig.). 11).

Next, a method for manufacturing the nanogap electrode structure 50 will be described. The method for manufacturing the nanogap electrode structure 50 is as follows: first, an insulating film forming step (see FIGS. 4A and 4B), a nanopore forming step (see FIGS. 5A and 5B), and a nanopore embedding step (see FIGS. 5A and 5B), as in the first embodiment. 6A and 6B), an electrode forming step (see FIGS. 7A and 7B), and a flow path forming step (see FIGS. 8A and 8B) are performed. Then, after the flow path forming step, the wet etching solution is flowed from the nanopore 23, wet etching is performed on the back surface of the nanopore upper region 25 of the nanogap electrode 22, and the back surface of the nanopore upper region 25 is partially removed in the thickness direction. Then, the nanopore upper region 25 is thinned. When the back surface of the nanopore upper region 25 is removed by wet etching, the nanogap electrode 22 is isotropically etched, so that the back surface of the connection region 26 is also partially removed in the thickness direction of the nanopore upper region 25. The sides and sides of the connection area 26 are also partially removed in the width direction. As a result, dents are formed on the back surface and the side surface of the nanogap electrode 22 in the vicinity of the nanopore 23. The nanogap electrode 22 having dents formed on the back surface and the side surface in the vicinity of the nanopore 23 is the nanogap electrode 52 (see FIG. 12) having a thin-walled portion 57.

The thin-walled portion 57 is not limited to the one having a shape in which the back surface and the side surface of the nanogap electrode 52 are recessed. A modified example of the thin-walled portion 57 will be described below.

As shown in FIG. 13, the thin-walled portion 58 is a portion in which the side surface of the nanogap electrode 52 is not recessed and only the back surface of the nanogap electrode 52 is recessed. When the side surface of the nanogap electrode 52 is not recessed and only the back surface is recessed, for example, the back surface of the nanopore upper region 25 (see FIGS. 8A and 8B) of the nanogap electrode 22 after the flow path forming step is dry-etched. Anisotropic etching is performed. Further, instead of forming a dent on the back surface of the nanogap electrode 52, a dent may be formed on the front surface of the nanogap electrode 52, or a dent may be formed on both the front surface and the back surface of the nanogap electrode 52. Instead of performing wet etching or dry etching, an electron beam may be irradiated. When an electron beam is used, the nanopore upper region 55 having a fine groove can also be formed. Since the cross-sectional area of the groove portion of the nanopore upper region 55 is smaller than that of the connection region 56, disconnection due to electromigration is likely to occur.

[Third Embodiment]
FIG. 14 is an enlarged view of the vicinity of the nanopore 13 of the nanogap electrode structure 60 according to the third embodiment.

The nanogap electrode structure 60 includes an insulating film 11 and a nanogap electrode 62 provided on the insulating film 11. The nanogap electrode 62 has a pair of electrode portions 64a and 64b. The pair of electrode portions 64a and 64b are located above the nanopore 13 and the nanopore upper region 65 (first nanopore upper region 65a, second nanopore upper region 65b) and above the insulating film 11 and are located above the nanopore. It has a connection area 66 (first connection area 66a, second connection area 66b) connected to the area 65. The nanopore upper region 65 is provided with a nanogap 17 that connects to the nanopore 13.

In the third embodiment, the configuration of the nanopore upper region 65 is different from the nanopore upper region 15 according to the first embodiment and the nanopore upper region 55 according to the second embodiment. In the third embodiment, for example, after the flow path forming step shown in FIGS. 8A and 8B, ion implantation is performed into the nanopore upper region 25 of the nanogap electrode 22 to change the material of the nanopore upper region 25. Examples of the element to be injected into the nanopore upper region 25 include Si, Ni, Ti, Cr and the like. The altered nanopore upper region 25 is the nanopore upper region 65 according to the third embodiment. The method of altering the nanopore upper region 25 is not limited to the ion implantation method described above. For example, the substrate 20 and the insulating film 21 may be used as masks for plasma treatment or annealing treatment such as laser annealing or electron beam annealing.

The nanopore upper region 65 contains a alteration of the material constituting the connection region 66. In the altered nanopore upper region 65, disconnection due to electromigration is more likely to occur than in the unaltered connection region 66, so that the nanogap 17 is surely formed.

FIG. 15 is an enlarged view showing a state in which the first electrode portion 64a and the second electrode portion 64b of the nanogap electrode structure 60 are not cut. By applying a voltage between the pair of electrode portions 64a and 64b connected to each other, it is possible to generate a disconnection due to electromigration in the nanopore upper region 65 and form a nanogap 17 in the nanopore upper region 65 (Fig.). 14).

It should be noted that the nanopore upper region having a thickness smaller than that of the connecting region may be altered as in the second embodiment. That is, the nanopore upper region may be smaller in thickness than the connection region and may contain a altered material in which the material constituting the connection region is altered.

[Fourth Embodiment]
As shown in FIG. 16, the nanogap electrode structure 70 according to the fourth embodiment includes an adhesive layer 71 for adhering the nanogap electrode 12 to the insulating film 11. The same members as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The adhesive layer 71 is provided between the insulating film 11 and the nanogap electrode 12. The adhesive layer 71 is in contact with the connection region 16 of the nanogap electrode 12 and is not in contact with the nanopore upper region 15. The adhesive layer 71 has a portion corresponding to the nanopore 13 open. The material of the adhesive layer 71 is, for example, Ti, Cr, or the like. The thickness of the adhesive layer 71 is, for example, 2 nm. The outer shape of the adhesive layer 71 in a plan view is not particularly limited, but a similar shape similar to that of the nanogap electrode 12 or larger than the nanogap electrode 12 is preferable.

An example of a method for forming the adhesive layer 71 will be described below. After performing the insulating film forming step (see FIGS. 4A and 4B), the nanopore forming step (see FIGS. 5A and 5B), and the nanopore embedding step (see FIGS. 6A and 6B), the adhesive layer forming step, the electrode forming step, and the flow path forming are performed. Perform the process and the adhesive layer removal process. Since the insulating film forming step, the nanopore forming step, and the nanopore embedding step are the same as those in the first embodiment, the description thereof will be omitted.

As shown in FIGS. 17A and 17B, in the adhesive layer forming step, the adhesive layer 72 is formed on the insulating film 21. First, a photoresist is applied to the insulating film 21 to form a photoresist layer (not shown), and the photoresist layer is patterned by a photolithography technique. In this example, a resist pattern is formed on the photoresist layer so that the outer shape of the adhesive layer 72 in a plan view has the same shape as the nanogap electrode 12 of the nanogap electrode structure 70. The portion of the insulating film 21 that forms the adhesive layer 72 is exposed, and the portion that does not form the adhesive layer 72 is covered with the photoresist layer. Next, a Ti film is formed on the photoresist layer and on the exposed insulating film 21 by performing a sputtering method using, for example, Ti as the target material. An adhesive layer 72 having a portion corresponding to the nanopore upper region 25 of the nanogap electrode 22 and a portion corresponding to the connection region 26 is formed.

As shown in FIGS. 18A and 18B, in the electrode forming step, an Au film is formed on the adhesive layer 72 by performing a sputtering method using Au as a target material. Next, the lift-off method is performed to remove the adhesive layer 72 and the Au film on the photoresist layer together with the photoresist layer. The Nanogap electrode 22 is formed by the Au film remaining on the adhesive layer 72.

Next, a flow path forming step (see FIGS. 8A and 8B) is performed. Since the flow path forming step is the same as that of the first embodiment, detailed description thereof will be omitted, but the protective film is formed, the flow path 29 is formed, and the deposit film 27 is removed.

As shown in FIGS. 19A and 19B, the adhesive layer removing step removes the portion of the adhesive layer 72 that is in contact with the nanopore upper region 25 of the nanogap electrode 22. In the adhesive layer removing step, a part of the adhesive layer 72 is sputter-etched from the back surface of the substrate 20. As a result, the portion of the adhesive layer 72 that is in contact with the nanopore upper region 25 of the nanogap electrode 22 is removed, and the portion that is in contact with the connection region 26 of the nanogap electrode 22 remains. The adhesive layer 72 has a portion corresponding to the nanopore 23 opened. The portion of the adhesive layer 72 in contact with the connection region 26 is the adhesive layer 71 (see FIG. 16). The method for removing a part of the adhesive layer 72 is not limited to the above-mentioned sputter etching, and for example, wet etching may be performed.

As described above, the nanogap electrode provided with the adhesive layer 71 by performing the insulating film forming step, the nanopore forming step, the nanopore embedding step, the adhesive layer forming step, the electrode forming step, the flow path forming step, and the adhesive layer removing step. The structure 70 is obtained (see FIG. 16).

The adhesive layer 71 is not limited to the case where it is not in contact with the nanopore upper region 15 of the nanogap electrode 12, and may be in contact with the nanopore upper region 15. When the adhesive layer 71 in contact with the nanopore upper region 15 is obtained, the adhesive layer removing step (see FIGS. 19A and 19B) is not performed, or the adhesive layer 72 remains on the back surface of the nanopore upper region 25 in the adhesive layer removing step. A part of the adhesive layer 72 is removed.

The adhesive layer forming step may be performed as the next step of the insulating film forming step (see FIGS. 4A and 4B). The case where the adhesive layer forming step is performed as the next step of the insulating film forming step will be described below.

As shown in FIGS. 20A and 20B, in the adhesive layer forming step, the adhesive layer 73 is formed on the insulating film 21. First, a photoresist is applied to the insulating film 21 to form a photoresist layer (not shown), and the photoresist layer is patterned by a photolithography technique. In this example, a resist pattern is formed on the photoresist layer so that the outer shape of the adhesive layer 73 in a plan view has a shape similar to that of the nanogap electrode 12 of the nanogap electrode structure 70. In FIG. 20A, the portion corresponding to the outer shape of the nanogap electrode 12 of the nanogap electrode structure 70 is shown by a dotted line. The portion of the insulating film 21 that forms the adhesive layer 73 is exposed, and the portion that does not form the adhesive layer 73 is covered with the photoresist layer. Next, a Ti film is formed on the photoresist layer and on the exposed insulating film 21 by performing a sputtering method using, for example, Ti as the target material. An adhesive layer 73 having a portion corresponding to the nanopore upper region 25 of the nanogap electrode 22 and a portion corresponding to the connection region 26 of the nanogap electrode 22 is formed.

As shown in FIGS. 21A and 21B, the nanopore forming step forms the nanopore 23 on the insulating film 21. A photoresist is applied to the adhesive layer 73 and the insulating film 21 to form a photoresist layer, the photoresist layer is patterned by photolithography technology, and the bonded layer 73 and the insulating film 21 are formed using the patterned photoresist layer as a mask. Is dry etched. As a result, the nanopore 23 is formed on the insulating film 21. Since the portion corresponding to the nanopore 23 is opened, the adhesive layer 73 does not have a portion in contact with the nanopore upper region 25 of the nanogap electrode 22 formed in the electrode forming step which is the next step. Therefore, the nanopore forming step includes an adhesive layer removing step of removing the portion of the adhesive layer 73 in contact with the nanopore upper region 25 of the nanogap electrode 22.

After the nanopore forming step, the nanogap electrode structure 70 including the adhesive layer 71 is obtained by performing the nanopore embedding step, the electrode forming step, and the flow path forming step in the same manner as in the first embodiment (see FIG. 16). ).

[Fifth Embodiment]
FIG. 22 is an enlarged view of the vicinity of the nanopore 13 of the nanogap electrode structure 80 according to the fifth embodiment.

The nanogap electrode structure 80 includes an insulating film 11 and a nanogap electrode 82 provided on the insulating film 11. The nanogap electrode 82 has a pair of electrode portions 84a and 84b. The pair of electrode portions 84a and 84b are located above the nanopore 13 and the nanopore upper region 85 (first nanopore upper region 85a, second nanopore upper region 85b) and above the insulating film 11 and are located above the nanopore. It has a connection region 86 (first connection region 86a, second connection region 86b) to be connected to the region 85. The nanopore upper region 85 is provided with a nanogap 17 that connects to the nanopore 13.

The nanogap electrode 82 has a single-layer structure in the nanopore upper region 85 and a laminated structure in the connection region 86, so that the thickness of the nanopore upper region 85 is smaller than the thickness of the connection region 86. The boundary between the single-layer structure and the laminated structure has the same position as the boundary between the nanopore upper region 85 and the connection region 86 in FIG. 22.

The nanogap electrode 82 is composed of a first layer 82a provided on the insulating film 11 and a second layer 82b provided on the first layer 82a and the nanopore 13. The first layer 82a is provided only on the insulating film 11 and not on the nanopore 13. The second layer 82b has a stepped shape, and the positions (heights) in the Z-axis direction are different between the portion provided on the first layer 82a and the portion provided on the nanopore 13. The outer shape of the second layer 82b in a plan view is the same as the outer shape of the first layer 82a in this example, but may be a similar shape.

In the nanogap electrode 82, the nanopore upper region 85 is composed of the second layer 82b, and the connection region 86 is composed of the first layer 82a and the second layer 82b. In other words, the nanogap electrode 82 has a single-layer structure in the nanopore upper region 85 and a laminated structure in the connection region 86, and the thickness of the nanopore upper region 85 is smaller than the thickness of the connection region 86. Specifically, the minimum thickness of the nanopore upper region 85 is smaller than the minimum thickness of the connecting region 86. Therefore, in the plane (YZ plane) orthogonal to the direction in which the current flows between the pair of electrode portions 84a and 84b (X-axis direction), the minimum cross-sectional area of the nanopore upper region 85 is the cross-sectional area of the connection region 86. Less than the minimum value of. In the nanopore upper region 85, which is thinner than the connection region 86, the current density is higher than that in the connection region 86, and disconnection due to electromigration is more likely to occur, so that the nanogap 17 is surely formed.

A nanogap 17 can be formed in the nanopore upper region 85 as long as it has at least a single layer structure in the nanopore upper region 85. Therefore, the boundary between the single-layer structure and the laminated structure is not limited to the case where it is held at the same position as the boundary between the nanopore upper region 85 and the connection region 86 as described above, and exists in the nanopore upper region 85 or the connection region 86. You may.

The first layer 82a and the second layer 82b are formed of the same material (for example, Au) in this example, but may be formed of different materials. When the first layer 82a and the second layer 82b are formed of different materials, for example, Ti or Cr can be used as the first layer 82a, Au, Pt or the like can be used as the second layer 82b in combination. At this time, the surface of the first layer 82a may be cleaned before the film formation of the second layer 82b is formed.

FIG. 23 is an enlarged view showing a state in which the first electrode portion 84a and the second electrode portion 84b of the nanogap electrode structure 80 are not cut. By applying a voltage between the pair of electrode portions 84a and 84b connected to each other, it is possible to generate a disconnection due to electromigration in the nanopore upper region 85 and form a nanogap 17 in the nanopore upper region 85 (Fig.). 22).

Next, a method for manufacturing the nanogap electrode structure 80 will be described. The method for manufacturing the nanogap electrode structure 80 is as follows: first, an insulating film forming step (see FIGS. 4A and 4B), a nanopore forming step (see FIGS. 5A and 5B), and a nanopore embedding step (see FIGS. 5A and 5B), as in the first embodiment. 6A, 6B). Then, after the nanopore embedding step, an electrode forming step and a flow path forming step are performed.

The electrode forming step includes a first layer forming step and a second layer forming step. The electrode forming step according to the fifth embodiment will be described with reference to FIGS. 24A and 24B to 25A and 25B.

As shown in FIGS. 24A and 24B, in the first layer forming step, the first layer 92a is formed on the insulating film 21. First, a photoresist is applied to the insulating film 21 to form a photoresist layer (not shown). By patterning the photoresist layer by a photolithography technique, the portion of the insulating film 21 that forms the first layer 92a is exposed, and the portion that does not form the first layer 92a is covered with the photoresist layer. In the first layer forming step, since the first layer 92a is not formed on the nanopore 23, the deposit film 27 in the nanopore 23 is covered with the photoresist layer. Next, an Au film is formed on the photoresist layer and on the exposed insulating film 21 by performing a sputtering method using Au as the target material. Next, the Au film on the photoresist layer is removed together with the photoresist layer by performing a lift-off method. The first layer 92a is formed by the Au film remaining on the insulating film 21.

As shown in FIGS. 25A and 25B, the second layer forming step forms the second layer 92b on the first layer 92a and the nanopore 23. First, a photoresist is applied to the insulating film 21 and the first layer 92a to form a photoresist layer (not shown). By patterning the photoresist layer by a photolithography technique, the portion forming the second layer 92b is exposed, and the portion not forming the second layer 92b is covered with the photoresist layer. In the second layer forming step, the second layer 92b is partially formed on the nanopore 23 so that the width becomes smaller toward the center of the nanopore 23. Therefore, the portion of the deposit film 27 in the nanopore 23 that does not form the second layer 92b is covered with the photoresist layer. Next, an Au film is formed on the first layer 92a and on the photoresist layer by performing a sputtering method using Au as the target material. Next, the Au film on the photoresist layer is removed together with the photoresist layer by performing a lift-off method. The Au film remaining on the first layer 92a and the deposit film 27 forms the second layer 92b.

As shown in FIGS. 26A and 26B, in the flow path forming step, for example, the flow path 29 connected to the nanopore 23 is formed on the substrate 20 by the same method as in the first embodiment. After forming the flow path 29 on the substrate 20, the deposit film 27 is removed by wet etching using, for example, HF as a wet etching solution.

As described above, the nanogap electrode structure is formed by performing the insulating film forming step, the nanopore forming step, the nanopore embedding step, the electrode forming step having the first layer forming step and the second layer forming step, and the flow path forming step. 80 is obtained (see FIG. 23).

In the nanogap electrode 82, the second layer 82b has a stepped shape as described above, and the portion provided on the first layer 82a and the portion provided on the nanopore 13 are in the Z-axis direction. It is not limited to the case where the positions (heights) are different. For example, the second layer 82b may have the same position in the Z-axis direction between the portion provided on the first layer 82a and the portion provided on the nanopore 13. After performing the first layer forming step (see FIGS. 24A and 24B), a deposit film is further formed on the deposit film 27, and the second layer forming step (FIG. 25A and 25B) is performed. As a result, the second layer 82b having no step shape can be formed.

The outer shape of the first layer 82a in a plan view can be changed in size by changing the range in which the first layer 92a is formed in the first layer forming step. The outer shape of the second layer 82b in a plan view can be changed in size by changing the range in which the second layer 92b is formed in the second layer forming step.

The nanogap electrode 82 is not limited to the case where the first layer 82a is provided only on the insulating film 11 and is not provided on the nanopore 13 as described above. Although not shown, the first layer 82a may be provided on the insulating film 11 and the nanopore 13. When the first layer 82a is provided on the nanopore 13, the second layer 82b is provided only on the first layer 82a and not on the nanopore 13. As a result, the nanopore upper region 85 is composed of the first layer 82a, the connection region 86 is composed of the first layer 82a and the second layer 82b, and the thickness of the nanopore upper region 85 can be made smaller than the thickness of the connection region 86. ..

The present invention is not limited to each of the above embodiments as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in each of the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in each embodiment can be considered. Further, the components described in different embodiments may be combined as appropriate.

The nanogap electrode structure 10 according to the first embodiment and the nanogap electrode structure precursor 30 are not limited to the case where the nanogap electrode structure precursor 30 is provided to the analyzer 40. The nanogap electrode structure 60, the nanogap electrode structure 70 according to the fourth embodiment, and the nanogap electrode structure 80 according to the fifth embodiment may be provided to the analyzer 40.

10,50,60,70,80 Nanogap electrode structure 11,21 Insulation film 12,22,52,62,82 Nanogap electrode 13,23 Nanopore 14a, 24a, 54a, 64a, 84a Electrode part (first Electrode part)
14b, 24b, 54b, 64b, 84b Electrode part (second electrode part)
15,25,55,65,85 Nanopore upper region 15a, 25a, 55a, 65a, 85a First nanopore upper region 15b, 25b, 55b, 65b, 85b Second nanopore upper region 16,26,56,66, 86 Connection area 16a, 26a, 56a, 66a, 86a First connection area 16b, 26b, 56b, 66b, 86b Second connection area 17 Nanogap 18,20 Substrate 19,29 Channel 30 Nanogap electrode structure precursor 40 Analytical unit 31, 41 Power supply 42 Control unit 43 Ammeter 44 Analytical unit 71, 72, 73 Adhesive layer

Claims (11)

1. An insulating film with nanopores through which the sample passes, and
   A nanogap electrode provided on the insulating film and having a nanogap between a pair of electrode portions is provided.
   The pair of electrode portions has a nanopore upper region located above the nanopore and a connection region located above the insulating film and connected to the nanopore upper region.
   The nanogap is a nanogap electrode structure provided in the nanopore upper region.
2. The nanogap electrode structure according to claim 1, wherein the nanopore upper region is configured to induce disconnection due to electromigration by a current flowing when a voltage is applied between the pair of electrode portions.
3. The nanogap electrode according to claim 2, wherein the minimum value of the cross-sectional area of the nanopore upper region is smaller than the minimum value of the cross-sectional area of the connection region in a plane orthogonal to the direction in which a current flows between the pair of electrodes. Structure.
4. The nanogap electrode structure according to claim 3, wherein the thickness of the nanopore upper region is smaller than the thickness of the connection region.
5. The nanogap electrode structure according to any one of claims 2 to 4, wherein the nanopore upper region contains a altered product in which the material constituting the connection region is altered.
6. An adhesive layer provided between the insulating film and the nanogap electrode is provided.
   The nanogap electrode structure according to any one of claims 1 to 5, wherein the adhesive layer is in contact with the connection region and is not in contact with the nanopore upper region.
7. A preparatory step for preparing a nanogap electrode provided on an insulating film having a nanopore and composed of a pair of electrode portions having a nanopore upper region located above the nanopore.
   A method for manufacturing a nanogap electrode structure, comprising a nanogap forming step of applying a voltage between the pair of electrode portions and forming a nanogap in the nanopore upper region by electromigration.
8. The preparation step is
   The insulating film forming step of forming the insulating film on the substrate, and
   The nanopore forming step of forming the nanopore on the insulating film,
   An electrode forming step of forming the nanogap electrode on the insulating film and
   The method for manufacturing a nanogap electrode structure according to claim 7, further comprising a flow path forming step of forming a flow path connected to the nanopore on the substrate.
9. The nanogap electrode structure according to any one of claims 1 to 6.
   A power supply that applies a voltage between the pair of electrodes and
   An ammeter that detects the tunnel current flowing between the pair of electrodes,
   An analyzer including an analysis unit that analyzes a sample based on the current value of the tunnel current.
10. The first control in which the voltage of the power supply is set to the first voltage and the nanogap is formed between the pair of electrodes, and the voltage of the power supply is a second voltage different from the first voltage. The analyzer according to claim 9, further comprising a control unit for performing the second control for generating the tunnel current between the pair of electrode units.
11. The first step of forming a nanogap in a nanogap electrode provided on an insulating film having nanopores and composed of a pair of electrode portions having a nanopore upper region located above the nanopores.
    An analysis method comprising a second step of detecting a tunnel current when a sample passes through the nanogap and analyzing the sample based on the current value of the tunnel current.
    
    

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