CN117233234A - Biomolecular sensor based on gallium nitride transistor and manufacturing method thereof - Google Patents
Biomolecular sensor based on gallium nitride transistor and manufacturing method thereof Download PDFInfo
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Abstract
The application discloses a biomolecular sensor based on a gallium nitride transistor and a manufacturing method thereof. A gallium nitride transistor-based biomolecular sensor comprising: a substrate; the buffer layer, the channel layer, the insertion layer, the barrier layer, the cap layer, the ohmic contact layer and the first metal electrode are sequentially arranged on one side of the substrate, and the channel layer and the barrier layer form a heterojunction; and a passivation layer covering a portion of a surface of the channel layer remote from the substrate and at least a portion of a surface of the first metal electrode remote from the substrate; the biomolecular sensor is provided with a nanopore channel, and the nanopore channel penetrates through the passivation layer, the barrier layer, the insertion layer and the channel layer; the channel layer is divided into a first part, a second part and a third part from inside to outside, wherein the thickness of the first part is H 1 The thickness of the second part is H 2 The third partThickness H 3 ，H 2 ＞H 1 ，H 2 ＞H 3 . When the biomolecules pass through the nanopore channels, significant current changes can be induced, thereby achieving detection and information storage of the biomolecules.
Description
Technical Field
The application relates to the technical field of semiconductor devices, in particular to a biomolecular sensor based on a gallium nitride transistor and a manufacturing method thereof.
Background
In the last decades, nanopores and nanochannels have been widely used in the fields of molecular detection and molecular storage as the most potential platform for single biomolecule detection and manipulation. Among them, nanopore-based biomolecule detection has the advantages of low cost, no label, very long read length, no need for amplification, and is considered to be the most promising method for achieving single biomolecule detection.
Molecular detection based on an ion blocking current method has been successfully applied to various solid-state nanopores, and the principle is that the surface of the molecule is charged, so that the molecule can pass through the nanopores under the drive of electrophoretic force, thereby blocking the original ion current to a certain extent and changing the current. Since the change caused by blocking current is mainly dependent on the physical size of the molecule to be detected, detection of smaller molecules places higher demands on the size of the nanopore. However, while the nanopore size is further scaled down to accommodate small molecule detection requirements, the corresponding ion current will also decrease as the size of the nanopore is scaled down, ultimately resulting in a decrease in the signal-to-noise ratio of the resulting signal.
Thus, the detection of biomolecules with small dimensions using common solid state nanopores still faces serious challenges, and current biomolecular sensors and methods for their fabrication remain to be improved.
Disclosure of Invention
The present application aims to at least partially alleviate or solve at least one of the above mentioned problems. The application provides a biomolecular sensor based on a gallium nitride transistor, wherein a heterojunction formed by a channel layer and a barrier layer is used as a medium of a nanopore channel, two-dimensional electron gas can be formed at the interface of the heterojunction formed by the channel layer and the barrier layer, so that on one hand, the channel based on the two-dimensional electron gas has ultrahigh conductivity and high corresponding reference current, on the other hand, the nanopore channel has ultrahigh sensitivity to surface states, so that the channel conductivity of biomolecules can be changed rapidly when the biomolecules pass through the nanopore channel, and huge current change can be generated when the biomolecules pass through the nanopore channel, thereby obtaining the information of the biomolecules according to a measured current change curve and realizing detection and information storage of the biomolecules.
In view of this, in one aspect of the present application, the present application provides a biomolecular sensor based on gallium nitride transistors. In some embodiments of the application, a gallium nitride transistor-based biomolecular sensor includes: a substrate; the buffer layer, the channel layer, the insertion layer, the barrier layer, the cap layer, the ohmic contact layer and the first metal electrode are sequentially arranged on one side of the substrate, and the channel layer and the barrier layer form a heterojunction; and a passivation layer covering a portion of a surface of the channel layer remote from the substrate and at least a portion of a surface of the first metal electrode remote from the substrate; the biomolecular sensor has a nanopore channel that extends through the passivation layer, the barrier layer, the insertion layer, and the channel layer; the channel layer is divided into a first part, a second part and a third part from inside to outside, the first part surrounds the nanopore channel, and the thickness of the first part is H 1 The thickness of the second part is H 2 The thickness of the third part is H 3 ，H 2 ＞H 1 ，H 2 ＞H 3 . Therefore, a heterojunction formed by the channel layer and the barrier layer can be used as a medium of a nanopore channel, and two-dimensional electron gas exists in the heterojunction, so that the channel has ultrahigh conductivity, the biomolecular sensor has larger reference current, and when biomolecules pass through the nanopore channel, remarkable current change can be caused, and detection and information storage of the biomolecules can be realized. The two-dimensional electron gas cannot migrate at high speed in the edge area (the area corresponding to the third part) of the biomolecular sensor, so that crosstalk between the biomolecular sensor and an adjacent structure or device can be effectively avoided; the thickness of the first part of the channel layer is thinner, which is beneficial to improving the sensitivity and accuracy of the biomolecular sensor test.
In some embodiments of the application, the gallium nitride transistor-based biomolecular sensor further comprises a masking layer on at least a portion of a surface of the substrate remote from the passivation layer. The masking layer can play a role in protecting the substrate, and can at least alleviate or even avoid the problem that the substrate is oxidized or corroded by electrolyte to a certain extent, thereby being beneficial to improving the stability of the biomolecular sensor.
In some embodiments of the present application, the material of the masking layer includes at least one of silicon oxide, silicon nitride, and chromium; the thickness of the masking layer is 50nm-2000nm.
In some embodiments of the application, the barrier layer is divided into a fourth portion and a fifth portion from inside to outside, the fourth portion surrounding the nanopore tunnel, the fourth portion having a thickness H 4 The thickness of the fifth part is H 5 ，H 5 ≥H 4 . Therefore, the thickness of the barrier layer close to the nanopore channel is thinner, which is beneficial to further improving the sensitivity and accuracy of the biomolecular sensor during test.
In some embodiments of the application, the gallium nitride transistor-based biomolecular sensor satisfies at least one of the following conditions: h is less than or equal to 10nm 1 ≤100nm；0.2μm≤H 2 ≤10μm；10nm≤H 4 ≤50nm；10nm≤H 5 Less than or equal to 1000nm; the nanopore channel is a cylindrical through hole or a conical through hole; the aperture of the nanopore channel is 10nm-100nm; the substrate is made of silicon; the material of the buffer layer, the material of the channel layer and the material of the cap layer respectively and independently comprise GaN; the thickness of the buffer layer is 0.5-10 mu m; the thickness of the cap layer is less than or equal to 10nm; the material of the insertion layer comprises AlN; the thickness of the insertion layer is 0.5nm-3nm; the barrier layer is made of at least one of AlGaN and InGaN; the ohmic contact layer is made of at least one of Ti, al, ni and Au; the material of the first metal electrode comprises at least one of Ti and Au; the passivation layer is made of at least one of silicon oxide, hafnium oxide and aluminum oxide; the thickness of the passivation layer is 50nm-600nm; the biomolecular sensor further comprises a second metal electrode, wherein the orthographic projection of the second metal electrode on the channel layer has an overlapping area with the third part, and the second metal electrode is connected with the first metal electrode; orthographic projection of the substrate on the channel layer The first portion has no overlapping area. Thus, the overall performance of the biomolecular sensor is further improved.
In another aspect of the application, a method of fabricating a gallium nitride transistor-based biomolecular sensor is presented. In some embodiments of the application, a method of fabricating a gallium nitride transistor-based biomolecular sensor includes: providing an original substrate, wherein the original substrate is provided with a first preset area, a second preset area and a third preset area, the second preset area surrounds the first preset area, and the third preset area surrounds the second preset area; forming an original buffer layer, an original channel layer, an original insertion layer, an original barrier layer and an original cap layer on one side of the original substrate in sequence; etching the original channel layer, the original insertion layer, the original barrier layer and the original cap layer on the third preset region, and thinning the thickness of the original channel layer on the third preset region; etching the original cap layer and the original barrier layer on the first preset area, and thinning the thickness of the original barrier layer on the first preset area to obtain the cap layer; forming an ohmic contact layer on one side of the cap layer away from the original substrate; forming a first metal electrode and an original passivation layer, wherein the first metal electrode is positioned on one side of the ohmic contact layer away from the original substrate, the original passivation layer covers a part of the surface of the original channel layer away from the original substrate, at least a part of the surface of the original barrier layer on the first preset area away from the original substrate and at least a part of the surface of the first metal electrode away from the original substrate; locally etching the original substrate to obtain a substrate, and exposing the original buffer layer; etching the original buffer layer and the original channel layer, and thinning the thickness of at least part of the original channel layer on a first preset area to form a first groove, thereby obtaining a buffer layer; and etching the thinned original channel layer, the thinned original insertion layer, the thinned original barrier layer and the thinned original passivation layer to form a nanopore channel, so as to obtain the channel layer, the insertion layer, the barrier layer and the passivation layer, wherein the nanopore channel penetrates through the passivation layer, the barrier layer, the insertion layer and the channel layer. The barrier layer and the channel layer in the biomolecular sensor manufactured by the method can form a heterojunction, two-dimensional electron gas can be generated in the heterojunction, so that the biomolecular sensor has larger reference current, larger current change can be caused when biomolecules pass through a nanopore channel, and the structural information of the corresponding biomolecules can be obtained by analyzing the change rule of a current curve, thereby realizing biomolecular detection and biomolecular information storage.
In some embodiments of the present application, the method of fabricating a gallium nitride transistor-based biomolecular sensor further comprises the step of forming an original masking layer on a surface of the original substrate that is remote from the original buffer layer, wherein in the step of etching the original substrate, the original masking layer is simultaneously etched, resulting in a masking layer that covers at least a portion of the surface of the substrate. Thus, the substrate can be protected by the masking layer, thereby improving the stability of the biomolecular sensor.
In some embodiments of the application, forming the first metal electrode and the original passivation layer comprises: depositing an original first passivation layer, wherein the original first passivation layer covers at least part of the surface of the original channel layer away from the original substrate and at least part of the surface of the ohmic contact layer away from the original substrate; etching the original first passivation layer to form an electrode hole; depositing a metal coating and carrying out patterning treatment on the metal coating to form a first metal electrode, wherein at least one part of the first metal electrode is positioned in the electrode hole; and depositing an original second passivation layer, wherein the original second passivation layer covers at least part of the surface of the first metal electrode, which is far away from the original substrate, and the rest of the original first passivation layer and the original second passivation layer form the original passivation layer.
In some embodiments of the present application, in the step of forming the first metal electrode, a second metal electrode is formed, the first metal electrode is connected to the second metal electrode, and the original second passivation layer covers at least a portion of a surface of the second metal electrode away from the original substrate. The biomolecule may be detected by connecting the second metal electrode lead to an external circuit or by applying pressure to the second metal electrode by a probe.
In some embodiments of the application, a method of fabricating a gallium nitride transistor-based biomolecular sensor satisfies at least one of the following conditions: etching the original cap layer and the original barrier layer on the first preset area by adopting focused ion beam equipment; etching the original buffer layer and the original channel layer by adopting focused ion beam equipment so as to thin the thickness of the original channel layer on the first preset area; the method of forming the original passivation layer includes at least one of atomic layer deposition and plasma enhanced chemical vapor deposition; and etching the thinned original channel layer, the thinned original insertion layer, the thinned original barrier layer and the thinned original passivation layer by adopting a focused ion beam device to form the nanopore channel. Therefore, the performance of the biomolecular sensor and the product manufacturing yield are further improved.
Drawings
The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 shows a schematic diagram of a structure of a bio-molecular sensor according to an embodiment of the present application;
FIG. 2 shows a partial schematic structure of a biomolecular sensor according to one embodiment of the present application;
FIG. 3 shows a schematic structural diagram of a bio-molecular sensor according to another embodiment of the present application;
FIG. 4 shows a schematic structural view of a bio-molecular sensor according to still another embodiment of the present application;
FIG. 5 shows a schematic partial flow diagram of a method for fabricating a biomolecular sensor according to one embodiment of the present application;
FIG. 6 shows a schematic partial flow diagram of a method for fabricating a biomolecular sensor according to one embodiment of the present application;
FIG. 7 is a schematic illustration of a partial flow diagram for fabricating a biomolecular sensor according to one embodiment of the present application;
FIG. 8 is a schematic view of a partial flow chart of a method for fabricating a biomolecular sensor according to one embodiment of the present application;
FIG. 9 shows a partial flow diagram of a fabrication of a biomolecular sensor according to one embodiment of the present application.
Reference numerals illustrate:
10: a substrate; 20: a buffer layer; 30: a channel layer; 31: a first portion; 32: a second portion; 33: a third section; 40: an interposer layer; 50: a barrier layer; 51: a fourth section; 52: a fifth section; 60: a cap layer; 70: a masking layer; 80: an ohmic contact layer; 90: a passivation layer; 1: a first metal electrode; 2: a second metal electrode; 3: a nanopore tunnel; 4: a first groove; 10': an original substrate; a: a first preset area; b: a second preset area; c: a third preset area; 20': an original buffer layer; 30': an original channel layer; 40': an original insertion layer; 50': an original barrier layer; 60': an original cap layer; 70': an original masking layer; 90': an original passivation layer; 2DEG: two-dimensional electron gas.
Detailed Description
Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application.
In one aspect, the present application provides a gallium nitride transistor-based biomolecular sensor. In some embodiments of the present application, referring to fig. 1 to 4, a gallium nitride transistor-based bio-molecular sensor may include a substrate 10, a passivation layer 90, and a buffer layer 20, a channel layer 30, an insertion layer 40, a barrier layer 50, a cap layer 60, an ohmic contact layer 80, and a first metal electrode 1 sequentially disposed at one side of the substrate 10. Wherein the channel layer 30 and the barrier layer 50 constitute a heterojunction, and the passivation layer 90 covers a portion of the surface of the channel layer 30 remote from the substrate 10 and at least a portion of the surface of the first metal electrode 1 remote from the substrate 10; the biomolecular sensor has a nanopore tunnel 3, the nanopore tunnel 3 extending through the passivation layer 90, the barrier layer 50, the interposer 40, and the channel layer 30. Ditch (groove) The track layer 30 is divided into a first part 31, a second part 32 and a third part 33 from inside to outside, the first part 31 surrounding the nanopore tunnel 3; referring to fig. 2, the first portion 31 has a thickness H 1 The second portion 32 has a thickness H 2 The third portion 33 has a thickness H 3 ，H 2 ＞H 1 ，H 2 ＞H 3 . In the biomolecular sensor, the channel layer and the barrier layer form a heterojunction, piezoelectric polarization and self-polarization effects can form a two-dimensional electron gas (2 DEG) with high electron mobility at the interface of the heterojunction, so that electron transportation is realized, on one hand, the channel based on the heterojunction has ultrahigh conductivity, so that the biomolecular sensor has larger reference current, on the other hand, the nanopore channel has ultrahigh sensitivity to surface states, and biomolecules (such as biological proteins, DNA and the like) can cause abrupt change of channel conductivity when passing through the nanopore channel, thereby causing larger current change of the biomolecules when passing through the nanopore channel, and accordingly, related structural information of the corresponding biomolecules can be obtained according to a current change curve. Compared with the second part of the channel layer, the third part is subjected to thinning treatment, the distance between the upper surface (the surface far away from the substrate) of the third part and the barrier layer is increased, and the two-dimensional electron gas (2 DEG) is not easy to quickly migrate in the third part, so that crosstalk between a biomolecular sensor and an adjacent structure or device can be avoided at least to a certain extent, and the detection sensitivity and accuracy of the sensor can be improved; compared with the second part of the channel layer, the first part is thinned, and the first part with smaller thickness is arranged close to the nanopore channel, so that the detection sensitivity and accuracy of the sensor are improved.
Herein, "surrounding" means that one portion of the structure is disposed around another portion of the structure.
It should be noted that, referring to fig. 1 to 4, the channel layer 30 is divided into a first portion 31, a second portion 32 and a third portion 33 from inside to outside, where the first portion 31 surrounds the nanopore tunnel 3, and the channel layer sequentially includes the first portion 31, the second portion 32 and the third portion 33 from near the nanopore tunnel to far from the nanopore tunnel, the second portion 32 surrounds the first portion 31, the third portion 33 surrounds the second portion 32, that is, the second portion 32 is adjacent to the first portion 31 and far from the nanopore tunnel 3, and the third portion 33 is adjacent to the second portion 32 and far from the nanopore tunnel 3.
In some embodiments of the application, 10 nm.ltoreq.H 1 Less than or equal to 100nm, e.g. H 1 The thickness of the first portion of the channel layer may be 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 60nm, 80nm, 100nm, etc., and is in the above range, which is advantageous for further improving the detection sensitivity and accuracy of the biomolecular sensor. In some embodiments of the present application, the thickness of the first portion 31 may be thinned to 10nm, so that the detection sensitivity and accuracy of the bio-molecular sensor may be significantly improved.
In some embodiments of the application, 0.2 μm.ltoreq.H 2 Less than or equal to 10 μm, e.g. H 2 May be 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 3 μm, 5 μm, 7 μm, 10 μm, etc.
In some embodiments of the present application, referring to fig. 1 to 4, the nanopore tunnel 3 may be a cylindrical through hole. In other embodiments of the present application, the nanopore tunnel 3 may also be a tapered via, which may gradually decrease or gradually increase in diameter in a direction of the substrate 10 toward the passivation layer 90.
In some embodiments of the present application, the pore diameter of the nanopore tunnel 3 may be 10nm-100nm, for example, the pore diameter of the nanopore tunnel 3 may be 10nm, 20nm, 50nm, 70nm, 100nm, etc., the pore diameter of the nanopore tunnel is smaller, the biomolecule sensor may allow a biomolecule with a smaller size to pass through, and the biomolecule may cause a larger current change when passing through the nanopore tunnel, so that information of the biomolecule may be obtained according to a current change rule, thereby realizing biomolecule detection and information storage. When the nanopore channel is a tapered through hole, the aperture of the nanopore channel refers to a diameter corresponding to a narrowest position of the tapered through hole channel.
In some embodiments of the present application, the material of the substrate 10 may comprise silicon. The surface of the silicon substrate can grow an epitaxial structure, so that various devices can be manufactured by taking the silicon substrate as a substrate according to actual requirements.
In some embodiments of the present application, the material of the buffer layer 20 may include GaN.
In some embodiments of the present application, the thickness of the buffer layer 20 may be 0.5 μm-10 μm, for example, the thickness of the buffer layer may be 0.5 μm, 0.8 μm, 1 μm, 3 μm, 5 μm, 7 μm, 10 μm, etc.
In some embodiments of the present application, the material of the channel layer 30 may include GaN.
In some embodiments of the present application, the material of the interposer 40 may include AlN. In some embodiments of the present application, the material of the interposer 40 may be AlN. The provision of the insertion layer can further prevent electrons from moving in a direction perpendicular to the upper surface of the channel layer (the surface of the channel layer away from the substrate), thereby facilitating the migration of two-dimensional electron gas in a plane.
In some embodiments of the present application, the thickness of the interposer 40 may be 0.5nm-3nm, for example, the thickness of the interposer 40 may be 0.5nm, 1nm, 1.5nm, 2nm, 2.5nm, 3nm, etc.
In some embodiments of the present application, the material of the barrier layer 50 may include at least one of AlGaN and InGaN. The barrier layer with the material can form a heterojunction structure with the channel layer, and two-dimensional electron gas with high electron mobility is generated at the interface of the barrier layer and the channel layer. In some embodiments of the present application, the material of the barrier layer 50 may be AlGaN or InGaN. In other embodiments of the present application, the barrier layer 50 may be made of AlGaN or InGaN.
In some embodiments of the present application, the material of the channel layer 30 may be GaN, the material of the barrier layer 50 may be AlGaN, and a heterojunction is formed by the channel layer and the barrier layer made of the above materials, and a two-dimensional electron gas with high electron mobility may be generated at the interface of the heterojunction, which is beneficial to further improving the detection accuracy and sensitivity of the biomolecular sensor.
In some embodiments of the present application, referring to fig. 1-4, the barrier layer 50 is divided from inside to outside into a fourth portion 51 and a fifth portion 52, the fourth portion 51 surrounding the nanopore tunnel 3,the fifth portion 52 surrounds the fourth portion 51, i.e. the fifth portion 52 is adjacent to the fourth portion 51 and remote from the nanopore tunnel 3. Referring to fig. 2, the fourth portion 51 has a thickness H 4 The fifth portion 52 has a thickness H 5 ，H 5 ≥H 4 . The fourth part is arranged close to the nanopore channel, and the thickness of the fourth part is thinner, so that the detection sensitivity and accuracy of the biomolecular sensor are further improved. In some embodiments of the application, the thickness H of the fourth portion 4 May be equal to the thickness H of the fifth portion 5 . In other embodiments of the present application, referring to FIG. 2, the thickness H of the fifth portion 5 May be greater than the thickness H of the fourth portion 4 。
In some embodiments of the application, 10 nm.ltoreq.H 4 50nm or less, e.g. thickness H of the fourth portion 51 4 May be 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc.
In some embodiments of the application, 10 nm.ltoreq.H 5 Less than or equal to 1000nm, e.g., thickness H of fifth portion 52 5 May be 10nm, 50nm, 100nm, 200nm, 500nm, 800nm, 1000nm, etc.
In some embodiments of the present application, the material of cap layer 60 may comprise GaN.
In some embodiments of the present application, the thickness of the cap layer 60 may be less than or equal to 10nm, for example, the thickness of the cap layer 60 may be 0.1nm, 0.5nm, 1nm, 3nm, 5nm, 8nm, 10nm, etc.
In some embodiments of the present application, referring to fig. 1-4, the gallium nitride transistor-based biomolecular sensor may further include a masking layer 70, and the masking layer 70 may be located on at least a portion of the surface of the substrate 10 remote from the passivation layer 90. The masking layer can play a role in protecting the substrate, so that the stability of the biomolecular sensor is improved, and the service life of the biomolecular sensor is prolonged.
In some embodiments of the present application, the material of the masking layer 70 may include at least one of silicon oxide, silicon nitride, chromium, and the like. In some embodiments of the present application, the masking layer 70 may be made of silicon oxide, silicon nitride or chromium. In other embodiments of the present application, the masking layer 70 may be made of two or three of silicon oxide, silicon nitride and chromium.
In some embodiments of the present application, the thickness of masking layer 70 may be 50nm-2000nm, for example, the thickness of masking layer 70 may be 50nm, 100nm, 500nm, 1000nm, 1500nm, 2000nm, etc. The thickness of the masking layer is set in the range, so that the protection effect of the masking layer on the substrate is improved, the stability of the biomolecular sensor is further improved, and the service life of the biomolecular sensor is further prolonged.
In some embodiments of the present application, the material of the ohmic contact layer 80 may include at least one of Ti, al, ni, au, etc., for example, the material of the ohmic contact layer 80 may be Ti, al, ni, or Au, and the material of the ohmic contact layer 80 may also include two or more of Ti, al, ni, and Au. Thus, the ohmic contact layer formed of the above material can improve the adhesion performance between the first metal electrode and the semiconductor material layer (e.g., the cap layer 60), so that the first metal electrode and the semiconductor material layer are firmly combined. In some embodiments of the present application, the ohmic contact layer may include a titanium layer, a titanium aluminum alloy layer, and/or a titanium gold alloy layer.
In some embodiments of the present application, the material of the first metal electrode 1 may include at least one of Ti and Au, for example, the material of the first metal electrode 1 may be Ti or Au, and the material of the first metal electrode 1 may also include both Ti and Au. The first metal electrode made of the material has good conductivity, and is beneficial to further improving the overall performance of the biomolecular sensor. In some embodiments of the present application, in order to further improve the adhesion performance of the first metal electrode and the ohmic contact layer, the first metal electrode and the ohmic contact layer may be bonded by a titanium metal layer or the like.
In some embodiments of the present application, the passivation layer 90 may include at least one of silicon oxide, hafnium oxide, and aluminum oxide, and the passivation layer has better insulation performance and can protect the layer structures such as the semiconductor material layer and the conductive structure layer. In some embodiments of the present application, the passivation layer 90 may be silicon oxide, hafnium oxide or aluminum oxide. In other embodiments of the present application, the passivation layer 90 may be made of two or three of silicon oxide, hafnium oxide, and aluminum oxide.
In some embodiments of the present application, the passivation layer 90 may have a thickness of 50nm-600nm, for example, the passivation layer 90 may have a thickness of 50nm, 80nm, 100nm, 150nm, 200nm, 300nm, 500nm, 600nm, etc. The passivation layer with the thickness can play a better role in protection, so that the stability of the sensor is further improved, and the service life of the sensor is further prolonged.
In the application, the thickness of each structural layer of the biomolecular sensor based on the gallium nitride transistor is thinner, which is beneficial to realizing the light weight and the miniaturization of the biomolecular sensor.
In some embodiments of the present application, referring to fig. 1, 3 and 4, the gallium nitride transistor-based bio-molecular sensor may further include a second metal electrode 2, an orthographic projection of the second metal electrode 2 on the channel layer 30 having an overlapping region with the third portion 33, the second metal electrode 2 being connected to the first metal electrode 1. Forming a second metal electrode in a region of the first metal electrode far away from the nanopore tunnel, and connecting the second metal electrode with a lead wire and then an external circuit, so that voltage can be provided for a biomolecule sensor through the external circuit to detect biomolecules; the detection may also be performed by applying pressure to the second metal electrode by a probe.
The positional relationship between the inner edge of the second portion 32 of the channel layer 30 and the inner edge of the fifth portion 52 of the barrier layer 50 is not particularly limited in the present application.
It should be noted that the "inner edge" refers to the edge of each layer structure or a part of the layer structure near the nanopore tunnel. "outer edge" refers to the edge of each layer structure or portion of a layer structure that is remote from the nanopore tunnel.
In some embodiments of the present application, referring to fig. 1 and 2, the spacing of the inner edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3 may be substantially identical to the spacing of the inner edge of the fifth portion 52 of the barrier layer 50 from the nanopore tunnel 3. "substantially uniform" means that it is difficult to ensure that the two pitches are exactly the same, about the same, during the manufacturing process.
In other embodiments of the present application, referring to fig. 3, the spacing of the inner edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3 may be greater than the spacing of the inner edge of the fifth portion 52 of the barrier layer 50 from the nanopore tunnel 3.
In further embodiments of the present application, referring to fig. 4, the spacing of the inner edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3 may be less than the spacing of the inner edge of the fifth portion 52 of the barrier layer 50 from the nanopore tunnel 3.
In the present application, the positional relationship between the inner edge of the substrate 10 and the outer edge of the second portion 32 of the channel layer 30 is not particularly limited.
In some embodiments of the present application, referring to fig. 1-4, the orthographic projection of the substrate 10 on the channel layer 30 has no overlapping area with the first portion 31 of the channel layer 30.
In some embodiments of the present application, referring to fig. 1 and 2, the spacing of the inner edge of the substrate 10 from the nanopore tunnel 3 may be greater than the spacing of the outer edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3.
In other embodiments of the present application, the spacing of the inner edge of the substrate 10 from the nanopore tunnel 3 may be substantially identical to the spacing of the outer edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3.
In further embodiments of the present application, referring to fig. 3 and 4, the spacing of the inner edge of the substrate 10 from the nanopore tunnel 3 may be less than the spacing of the outer edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3. In some embodiments of the present application, referring to fig. 3, the spacing of the inner edge of the substrate 10 from the nanopore tunnel 3 may be greater than the spacing of the inner edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3. In other embodiments of the present application, referring to fig. 4, the spacing of the inner edge of the substrate 10 from the nanopore tunnel 3 may be substantially identical to the spacing of the inner edge of the second portion 32 of the channel layer 30 from the nanopore tunnel 3.
The following describes the principle that the biomolecular (bioprotein, DNA, etc.) detection and information storage can be realized by the biomolecular sensor based on gallium nitride transistor according to the present application: taking DNA as an example for illustration, DNA is a macromolecular polymer composed of deoxynucleotides composed of bases, deoxyribose and phosphoric acid, and the bases can be divided into four types: adenine, thymine, cytosine and guanine. The size of each base is different, so that the corresponding current change is different when different bases pass through the nanopore channel, the current change can be calibrated before the detection of the biomolecules, the current change which can be caused by each base is known, and then the biomolecules are tested by a biomolecule sensor. When the DNA molecule is in a long-chain structure and passes through the nanopore channel, bases in the long-chain structure sequentially pass through the nanopore channel according to the arrangement sequence, and as the current change caused by each base passing through the nanopore channel is different, the sequence of the bases passing through the nanopore channel can be judged according to the tested current change curve, so that the structural information of biological protein or DNA and other biological molecules can be obtained according to the arrangement sequence of the bases. Therefore, the biomolecule sensor provided by the application can be used for biomolecule detection and storage, and particularly can be used for DNA sequencing.
In some embodiments of the present application, when testing biomolecules, a biomolecular sensor based on gallium nitride transistors may be placed in a conductive electrolyte solution, a bias voltage is applied, the whole loop is in a conductive state due to the existence of the nanopore channel, and the current magnitude is determined by both the electrolyte conductivity and the nanopore channel morphology. When the biomolecules pass through the nanopore channel, the nanopore channel is partially blocked, so that the overall resistance of the nanopore channel is increased, the current is reduced, which base passes through the nanopore channel is judged according to the variation of the current, and the specific structure of the biomolecules such as biological proteins or DNA can be judged according to the electrical characteristic variation curve obtained by testing.
In another aspect of the application, the application provides a method of fabricating a gallium nitride transistor-based biomolecular sensor. In some embodiments of the present application, referring to fig. 5 to 9, a method of fabricating a gallium nitride transistor-based bio-molecular sensor may include the steps of:
s10: a raw substrate 10' is provided.
Referring to fig. 5, the original substrate 10' has a first preset area a, a second preset area B surrounding the first preset area a, and a third preset area C surrounding the second preset area B.
In some embodiments of the present application, the material of the original substrate 10' may be silicon.
S20: an original buffer layer 20', an original channel layer 30', an original insertion layer 40', an original barrier layer 50', and an original cap layer 60 'are sequentially formed on one side of an original substrate 10'.
In some embodiments of the present application, referring to fig. 5, the original substrate 10', the original buffer layer 20', the original channel layer 30', the original insertion layer 40', the original barrier layer 50', and the original cap layer 60' are sequentially stacked.
In some embodiments of the present application, a silicon wafer may be used as a substrate, and an original channel layer, an original barrier layer, etc. may be grown on the substrate by a chemical vapor deposition method to form a heterojunction structure and a two-dimensional electron gas.
S30: the original channel layer 30', the original insertion layer 40', the original barrier layer 50', and the original cap layer 60' on the third preset region C are etched.
Referring to fig. 6, the original channel layer 30', the original insertion layer 40', the original barrier layer 50', and the original cap layer 60' on the third preset region C are etched, the original insertion layer 40', the original barrier layer 50', and the original cap layer 60' on the third preset region C are removed, and the thickness of the original channel layer 30' on the third preset region C is thinned, and the thinned original channel layer 30' on the third preset region C corresponds to the third portion 33 of the channel layer 30 in the fabricated gallium nitride transistor-based bio-molecular sensor.
In some embodiments of the present application, dry etching and/or wet etching may be used to remove the original cap layer 60', the original barrier layer 50', and the original insertion layer 40 'of the edge region, and to thin the original channel layer 30' of the edge region to cut off the heterojunction structure and the two-dimensional electron gas, thereby avoiding cross-talk of the biomolecular sensor with neighboring structures or devices.
In some embodiments of the present application, the original channel layer 30', the original insertion layer 40', the original barrier layer 50', and the original cap layer 60' may be selectively etched using an Inductively Coupled Plasma (ICP) apparatus. During etching, an etching medium (e.g., plasma) moves from the side of the original cap layer 60 'away from the original substrate 10' toward the device, the etching medium first contacts the original cap layer 60', and the etching depth reaches the original channel layer 30'.
S40: the original cap layer 60 'and the original barrier layer 50' on the first preset area a are etched.
In some embodiments of the present application, referring to fig. 6, the original cap layer 60' and the original barrier layer 50' on the first preset area a are etched, and the thickness of the original barrier layer 50' on the first preset area a is thinned, resulting in the cap layer 60.
In some embodiments of the present application, dry etching and/or wet etching may be used to remove the original cap layer 60 'on the first preset region a, and to thin the thickness of the original barrier layer 50' on the first preset region a. Before etching the original cap layer 60' and the original barrier layer 50', a photoresist layer may be formed on a side of the original cap layer 60' away from the original substrate 10' by photolithography, and the photoresist layer may be used as a mask to expose the original cap layer 60' on the first preset area a, and then etched.
In some embodiments of the present application, a Focused Ion Beam (FIB) device may be used to etch the original cap layer 60 'and the original barrier layer 50' over the first preset region a, remove the original cap layer 60 'over the first preset region a, and thin the thickness of the original barrier layer 50' over the first preset region a.
In some embodiments of the present application, the thickness of the original barrier layer 50' on the first preset area a may be thinned to 10nm-50nm by an etching process.
S50: an ohmic contact layer 80 is formed on a side of the cap layer 60 remote from the original substrate 10'.
In some embodiments of the present application, referring to fig. 7, the ohmic contact layer 80 may cover at least a portion of the surface of the cap layer 60 remote from the original substrate 10'.
In some embodiments of the present application, the ohmic contact layer may be grown using electron beam evaporation, magnetron sputtering, and/or Lift-Off processes.
In some embodiments of the present application, a metal layer may be deposited on at least a portion of the surface of cap layer 60 remote from the original substrate 10' and annealed to provide an ohmic contact layer 80. In some embodiments of the present application, titanium and aluminum may be deposited on the surface of cap layer 60 and annealed to form a titanium aluminum alloy, or titanium and gold may be deposited on the surface of cap layer 60 and rapidly annealed to form a titanium gold alloy, to form a good ohmic contact, and to connect with a two-dimensional electron gas (2 DEG).
S60: the first metal electrode 1 and the original passivation layer 90' are formed.
In some embodiments of the present application, referring to fig. 7, the first metal electrode 1 is located at a side of the ohmic contact layer 80 remote from the original substrate 10', and the original passivation layer 90' covers a portion of the surface of the original channel layer 30' remote from the original substrate 10', at least a portion of the surface of the original barrier layer 50' on the first preset region a remote from the original substrate 10', and at least a portion of the surface of the first metal electrode 1 remote from the original substrate 10 '.
In some embodiments of the present application, the method of forming the original passivation layer 90' may include at least one of Atomic Layer Deposition (ALD) and Plasma Enhanced Chemical Vapor Deposition (PECVD).
In some embodiments of the present application, forming the first metal electrode 1 and the original passivation layer 90' may include the steps of:
s61: an original first passivation layer is deposited.
In some embodiments of the present application, a raw first passivation layer is deposited, which may cover at least a portion of the surface of the raw channel layer 30' remote from the raw substrate 10' and at least a portion of the surface of the ohmic contact layer 80 remote from the raw substrate 10 '.
S62: etching the original first passivation layer to form an electrode hole.
In this step, the original first passivation layer is etched to form electrode holes exposing at least a portion of the surface of the ohmic contact layer 80 away from the original substrate 10'.
S63: and depositing a metal coating and carrying out patterning treatment on the metal coating to form a first metal electrode.
Referring to fig. 7, at least a portion of the first metal electrode 1 may be located in the electrode hole, and the first metal electrode 1 may be connected to the cap layer 60 through the ohmic contact layer 80.
S64: an original second passivation layer is deposited.
The original second passivation layer may cover at least a portion of the surface of the first metal electrode 1 remote from the original substrate 10', and the remaining original first passivation layer and the original second passivation layer constitute an original passivation layer 90'.
In some embodiments of the present application, in the step of forming the first metal electrode 1, the second metal electrode 2 may be formed, the first metal electrode 1 is connected to the second metal electrode 2, and the original second passivation layer may cover at least a portion of the surface of the second metal electrode 2 remote from the original substrate 10'.
In some embodiments of the present application, the first metal electrode and/or the second metal electrode may be grown using electron beam evaporation, magnetron sputtering, and/or Lift-Off processes.
S70: the original substrate 10' is locally etched.
Referring to fig. 8, the original substrate 10 'is partially etched to obtain the substrate 10, and the original buffer layer 20' is exposed so that the original buffer layer 20 'and the original channel layer 30' are subsequently etched.
In some embodiments of the present application, a photoresist layer may be coated on a side of the original substrate 10' remote from the original buffer layer 20', a portion of the photoresist layer may be removed by dry etching, and then the original substrate 10' may be etched using dry etching and/or wet etching.
In some embodiments of the present application, referring to fig. 5 and 8, the method of fabricating a gallium nitride transistor-based bio-molecular sensor may further include a step of forming an original masking layer 70' on a surface of the original substrate 10' on a side remote from the original buffer layer 20', and in the subsequent step of etching the original substrate 10', the original masking layer 70' is etched simultaneously to obtain a masking layer 70, and the masking layer 70 may cover at least a portion of the surface of the substrate 10.
In some embodiments of the present application, etching may be initiated from the side of original masking layer 70' remote from original substrate 10', with the etching medium first contacting original masking layer 70'.
S80: the original buffer layer 20 'and the original channel layer 30' are etched.
In some embodiments of the present application, referring to fig. 8, the original buffer layer 20' and the original channel layer 30' are etched, and the thickness of at least part of the original channel layer 30' on the first preset area a is thinned, so that the first recess 4 is formed, resulting in the buffer layer 20.
In some embodiments of the present application, the original buffer layer 20' and the original channel layer 30' may be etched using a focused ion beam apparatus to thin the thickness of the original channel layer 30' on the first preset area a and obtain the buffer layer 20.
In some embodiments of the present application, the thickness of the original channel layer 30' on the first preset region a may be thinned to 10nm-100nm.
S90: the thinned original channel layer 30', original insertion layer 40', thinned original barrier layer 50', original passivation layer 90' are etched to form the nanopore tunnel 3.
Referring to fig. 9, the thinned original channel layer 30', the thinned original insertion layer 40', the thinned original barrier layer 50', and the thinned original passivation layer 90' are etched to form a nanopore tunnel 3, and the channel layer 30, the insertion layer 40, the barrier layer 50, and the passivation layer 90 are obtained, where the nanopore tunnel 3 penetrates the passivation layer 90, the barrier layer 50, the insertion layer 40, and the channel layer 30.
In some embodiments of the present application, the thinned original channel layer 30', the original insertion layer 40', the thinned original barrier layer 50', and the original passivation layer 90' may be etched using a focused ion beam device, and etching may be started from a side of the original channel layer 30' near the substrate 10 to form the nanopore tunnel 3. The Focused Ion Beam (FIB) can process structures in a large area simultaneously, the etching rate can be adjusted by accelerating voltage, working current, beam spot size and the like, and the size of a nanopore channel in the preparation process can be accurately controlled so as to cope with biomolecule detection of different requirements.
Referring to fig. 9, after the nanopore tunnel 3 is formed, a biomolecular sensor may be obtained.
In the biomolecular sensor based on the gallium nitride transistor manufactured by the method, two-dimensional electron gas exists in the heterojunction of the channel layer and the barrier layer, so that the surface of the corresponding nanopore channel is very sensitive to the surface state of the ion channel, when the biomolecular passes through the nanopore channel, the rapid change of the conductivity of the corresponding nanopore channel can be caused, and finally, a larger via current signal can be obtained, thereby realizing detection and information storage of the biomolecular. The whole manufacturing process adopts a semiconductor process and MEMS (micro electro mechanical system) technology, can realize large-scale preparation, can reduce the manufacturing cost while realizing mass production, and is beneficial to improving the manufacturing yield of products.
The following describes in detail the steps for fabricating a gallium nitride transistor-based biomolecular sensor according to an embodiment of the present application. It will be appreciated by those skilled in the art that the following specific examples are for illustrative purposes only and are not intended to limit the scope of the present application in any way. In addition, in the examples below, materials and equipment used are commercially available unless otherwise specified. If in the following examples specific treatment conditions and treatment methods are not explicitly described, the treatment may be performed using conditions and methods well known in the art.
Example 1
1.1 A GaN buffer layer having a thickness of 2 μm is grown on a silicon substrate.
1.2 A GaN channel layer having a thickness of 2 μm, an AlN insertion layer having a thickness of 2nm, an AlGaN barrier layer having a thickness of 200nm, a GaN cap layer having a thickness of 3nm were grown in this order on the GaN buffer layer, and a silicon nitride masking layer having a thickness of 100nm was grown on the back surface (the surface of the silicon substrate away from the GaN buffer layer).
1.3 Selectively etching the edge region of the silicon substrate by using Inductively Coupled Plasma (ICP) equipment to form an etching table top, wherein the etching depth reaches the GaN channel layer.
1.4 Selectively etching the GaN cap layer and a portion of the AlGaN barrier layer by using a Focused Ion Beam (FIB) device to an etching depth of 193nm to thin the AlGaN barrier layer.
1.5 A metal layer (Ti/Al or Ti/Au) is deposited, and proper annealing conditions are selected to complete alloying of the metal system, so that good ohmic contact is formed and the metal system is connected with two-dimensional electron gas in the heterojunction.
1.6 Depositing a passivation layer by utilizing an Atomic Layer Deposition (ALD) technology, etching the passivation layer to form an electrode hole, then depositing a metal pattern layer (Ti/Au/Ti, a titanium layer of an adhesive layer can be formed, then a titanium-gold alloy layer is formed) and patterning, forming an interconnection electrode (a first metal electrode and a second metal electrode which are connected), and then depositing a second passivation layer (silicon oxide with the thickness of 300 nm) by utilizing the ALD technology.
1.7 The masking layer and the silicon substrate are selectively etched from the back side until the GaN buffer layer is exposed.
The GaN buffer layer and a portion of the GaN channel layer were selectively etched from the back side using a Focused Ion Beam (FIB) apparatus to an etch depth of 3.9 μm to thin a portion of the GaN channel layer.
1.8 Selectively etching the passivation layer, the AlGaN barrier layer, the AlN insertion layer and the GaN channel layer by adopting a Focused Ion Beam (FIB) device, starting etching from the back surface, and etching at the thinning position to form a nanopore channel with the diameter of 10nm-100nm, thereby obtaining the biomolecular sensor based on the gallium nitride transistor.
In the description of the present application, the orientation or positional relationship indicated by the terms "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the present application and do not require that the present application must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.
In the description of the present specification, reference to the term "one embodiment," "another embodiment," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction. In addition, it should be noted that, in this specification, the terms "first", "second", "third", "fourth" and "fifth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated.
While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.
Claims (10)
1. A gallium nitride transistor-based biomolecular sensor, comprising:
a substrate;
the buffer layer, the channel layer, the insertion layer, the barrier layer, the cap layer, the ohmic contact layer and the first metal electrode are sequentially arranged on one side of the substrate, and the channel layer and the barrier layer form a heterojunction; and
a passivation layer covering a portion of a surface of the channel layer remote from the substrate and at least a portion of a surface of the first metal electrode remote from the substrate;
the biomolecular sensor has a nanopore channel that extends through the passivation layer, the barrier layer, the insertion layer, and the channel layer;
the channel layer is coated from inside to outsideDivided into a first part, a second part and a third part, wherein the first part surrounds the nanopore channel, and the thickness of the first part is H 1 The thickness of the second part is H 2 The thickness of the third part is H 3 ，H 2 ＞H 1 ，H 2 ＞H 3 。
2. The biomolecular sensor of claim 1, further comprising a masking layer on at least a portion of a surface of the substrate remote from the passivation layer.
3. The biomolecular sensor according to claim 2, wherein said masking layer satisfies at least one of the following conditions:
the masking layer is made of at least one of silicon oxide, silicon nitride and chromium;
the thickness of the masking layer is 50nm-2000nm.
4. A biomolecular sensor according to any of claims 1-3, wherein the barrier layer is divided from inside to outside into a fourth portion surrounding the nanopore channel and a fifth portion, the fourth portion having a thickness H 4 The thickness of the fifth part is H 5 ，H 5 ≥H 4 。
5. The biomolecular sensor according to claim 4, wherein at least one of the following conditions is satisfied:
10nm≤H 1 ≤100nm；
0.2μm≤H 2 ≤10μm；
10nm≤H 4 ≤50nm；
10nm≤H 5 ≤1000nm；
the nanopore channel is a cylindrical through hole or a conical through hole;
the aperture of the nanopore channel is 10nm-100nm;
the substrate is made of silicon;
the material of the buffer layer, the material of the channel layer and the material of the cap layer respectively and independently comprise GaN;
The thickness of the buffer layer is 0.5-10 mu m;
the thickness of the cap layer is less than or equal to 10nm;
the material of the insertion layer comprises AlN;
the thickness of the insertion layer is 0.5nm-3nm;
the barrier layer is made of at least one of AlGaN and InGaN;
the ohmic contact layer is made of at least one of Ti, al, ni and Au;
the material of the first metal electrode comprises at least one of Ti and Au;
the passivation layer is made of at least one of silicon oxide, hafnium oxide and aluminum oxide;
the thickness of the passivation layer is 50nm-600nm;
the biomolecular sensor further comprises a second metal electrode, wherein the orthographic projection of the second metal electrode on the channel layer has an overlapping area with the third part, and the second metal electrode is connected with the first metal electrode;
an orthographic projection of the substrate on the channel layer has no overlapping area with the first portion.
6. A method of fabricating a gallium nitride transistor-based biomolecular sensor, comprising:
providing an original substrate, wherein the original substrate is provided with a first preset area, a second preset area and a third preset area, the second preset area surrounds the first preset area, and the third preset area surrounds the second preset area;
Forming an original buffer layer, an original channel layer, an original insertion layer, an original barrier layer and an original cap layer on one side of the original substrate in sequence;
etching the original channel layer, the original insertion layer, the original barrier layer and the original cap layer on the third preset region, and thinning the thickness of the original channel layer on the third preset region;
etching the original cap layer and the original barrier layer on the first preset area, and thinning the thickness of the original barrier layer on the first preset area to obtain the cap layer;
forming an ohmic contact layer on one side of the cap layer away from the original substrate;
forming a first metal electrode and an original passivation layer, wherein the first metal electrode is positioned on one side of the ohmic contact layer away from the original substrate, the original passivation layer covers a part of the surface of the original channel layer away from the original substrate, at least a part of the surface of the original barrier layer on the first preset area away from the original substrate and at least a part of the surface of the first metal electrode away from the original substrate;
locally etching the original substrate to obtain a substrate, and exposing the original buffer layer;
etching the original buffer layer and the original channel layer, and thinning the thickness of at least part of the original channel layer on a first preset area to form a first groove, thereby obtaining a buffer layer;
And etching the thinned original channel layer, the thinned original insertion layer, the thinned original barrier layer and the thinned original passivation layer to form a nanopore channel, so as to obtain the channel layer, the insertion layer, the barrier layer and the passivation layer, wherein the nanopore channel penetrates through the passivation layer, the barrier layer, the insertion layer and the channel layer.
7. The method of claim 6, further comprising the step of forming an original masking layer on a surface of the original substrate on a side remote from the original buffer layer, wherein in the step of etching the original substrate, the original masking layer is etched simultaneously to obtain a masking layer, the masking layer covering at least a portion of the surface of the substrate.
8. The method of claim 6 or 7, wherein forming the first metal electrode and the original passivation layer comprises:
depositing an original first passivation layer, wherein the original first passivation layer covers at least part of the surface of the original channel layer away from the original substrate and at least part of the surface of the ohmic contact layer away from the original substrate;
etching the original first passivation layer to form an electrode hole;
depositing a metal coating and carrying out patterning treatment on the metal coating to form a first metal electrode, wherein at least one part of the first metal electrode is positioned in the electrode hole;
And depositing an original second passivation layer, wherein the original second passivation layer covers at least part of the surface of the first metal electrode, which is far away from the original substrate, and the rest of the original first passivation layer and the original second passivation layer form the original passivation layer.
9. The method of claim 8, wherein in the step of forming the first metal electrode, a second metal electrode is formed, the first metal electrode being connected to the second metal electrode, the original second passivation layer covering at least a portion of a surface of the second metal electrode remote from the original substrate.
10. The method according to claim 6, 7 or 9, characterized in that at least one of the following conditions is fulfilled:
etching the original cap layer and the original barrier layer on the first preset area by adopting focused ion beam equipment;
etching the original buffer layer and the original channel layer by adopting focused ion beam equipment so as to thin the thickness of the original channel layer on the first preset area;
the method of forming the original passivation layer includes at least one of atomic layer deposition and plasma enhanced chemical vapor deposition;
and etching the thinned original channel layer, the thinned original insertion layer, the thinned original barrier layer and the thinned original passivation layer by adopting a focused ion beam device to form the nanopore channel.
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