Metal-doped supercapacitor microelectrode and preparation method thereof and biochip

Abstract

Disclosed are a metal-doped supercapacitor microelectrode, a preparation method thereof, and a biochip. According to the special combined properties of metal-doped transition metal oxynitrides and transition metal nitrides, the present disclosure proposes a microelectrode for a biochip, which may include: a substrate; a current collector layer formed on the substrate, the current collector layer including a nitride film of a first transition metal; an electrode layer formed on the current collector layer, the electrode layer including a oxynitride film of the first transition metal doped with a second metal. Optionally, the microelectrode of the present disclosure may also include an adhesion layer formed between the substrate and the current collector layer, the adhesion layer including a first transition metal film. The new metal-doped supercapacitor electrode material, current collector, and adhesion layer growth combination method proposed in the present disclosure can simultaneously meet the performance requirements of microelectrodes in biochips for high specific capacitance, fast time response, and high chemical stability.

Description

Technical Field

[0001] The present disclosure relates to biochip technology, and in particular to a metal-doped supercapacitor microelectrode and a preparation method thereof, and a biochip comprising the microelectrode. Background Art

[0002] Biochip technology is a chip technology for processing and analyzing biological information. It is widely used in biomolecule detection, including nucleic acid sequencing, protein sequencing and other biomolecule detection fields, and will involve the preparation of microelectrodes. The preparation of microelectrodes in the biochips used in the above-mentioned technology widely uses supercapacitor materials, which have the characteristics of high energy density and ultra-long cycle life. Microelectrodes usually include electrodes and current collectors. The electrodes realize the charge and discharge of charges through the energy storage mechanism, providing voltage drive for the biochemical system, and the current collector transports electrons and connects the charge and discharge and measurement circuits, providing charge and discharge currents for the electrodes and transmitting the characteristic current signals of sequencing and other detections to the measurement chip. When the biomolecule to be tested or its sequence passes through the nanopore, it will interact with the nanopore signal detection area to generate a characteristic microcurrent. The characteristics of the characteristic microcurrent, such as intensity and duration, are determined by the characteristics of the biomacromolecule to be tested or its sequence or its modifier, such as the type of base carried by the nucleotide, the type of amino acid residue in the protein sequence, and the nature of the nucleotide or protein modifier. The characteristic microcurrent can be detected by a semiconductor measurement chip connected to the electrode, thereby achieving the purpose of biomolecule detection such as nucleic acid sequencing and protein sequencing.

[0003] Nucleic acid sequencing and protein sequencing are very cutting-edge technologies. Combined with the technical direction of electrical signal detection, there are several aspects that need to be broken through at present:

[0004] 1. Voltage driving capability of microelectrodes: The flux of a biochip determines its detection cost and efficiency, which depends on the number of detection units that can be integrated per unit area, i.e., the detection unit density. The detection unit density is determined by the area of ​​a single detection unit. The controlling factor of this area is the voltage driving capability of its driving component, the microelectrode. High-throughput biochips require that the radius of the microelectrode be at the micrometer scale or even smaller, while still maintaining the required voltage driving capability. The original microelectrode materials and structures can no longer meet this requirement. It is necessary to achieve the required voltage driving capability by means of structural and material design combined with reasonable processing methods, etc., so as to give it a very high specific capacitance and fast time response (high charge and discharge rate).

[0005] 2. The microelectrode needs to work in the solution environment of the biochip, contact with the organic solvent required for detection, and needs to be charged and discharged for a long time. Therefore, its corrosion resistance and electrochemical stability are very important, which largely determines the service life of the biochip;

[0006] 3. Microelectrodes need to be easy to implement in low cost in MEMS technology so that they can be mass-produced.

[0007] Among the above requirements, high specific capacitance, fast time response and high electrochemical stability are the core technical indicators for electrode materials. In actual molecular detection applications, the electrode system composed of microelectrodes and common electrodes is charged and discharged under the load of an AC power supply with a frequency as low as 1 Hz. When the power supply voltage direction is switched, the charging and discharging process of the electrode system needs to be completed within tens of microseconds. At the same time, within this time range, the voltage difference between the microelectrode and the common electrode needs to be maintained within a certain range to ensure the acquisition of the characteristic microcurrent signal required to identify biological molecules such as nucleic acids and proteins or their sequences. On the one hand, the above working principle requires the microelectrode to have a high specific capacitance value to maintain a voltage difference with sufficient driving capability; it also requires the microelectrode to have a very high charge and discharge rate to ensure that the electrode system can complete the voltage conversion within a very short response time. Microelectrodes that meet the above requirements need to be able to obtain more than 10mF / cm when measured at a high scan rate cyclic voltammetry (CV) above 10V / s. 2 / μm specific capacitance value, and after 1000 cycles, it can still maintain more than 80% specific capacitance retention rate. This requires the microelectrode used to meet the stringent requirements of high specific capacitance and low resistivity at the same time.

[0008] At present, the microelectrodes commonly used in biochips used in biomolecular detection technologies such as gene sequencing are mainly metal nitride electrodes deposited on metal current collectors such as Al, Au, and Cu. Studies have shown that these materials can show more than 10mF / cm when measured by low-scan CV method. 2 / μm specific capacitance, but due to the high internal resistance of the electrode material and the high contact resistance between the electrode and the current collector, the specific capacitance value will decrease rapidly with the increase of the voltage scan rate. Only at a scan rate greater than 0.1V / s, the specific capacitance is lower than 4mF / cm 2 / μm, it cannot have both high specific capacitance and high charge and discharge rate at the same time, resulting in insufficient voltage driving capability per unit area, and it is impossible to reduce the required microelectrode size to below 5 microns, thereby achieving a single chip sequencing unit number exceeding tens of millions.

[0009] In recent years, high resistivity porous transition metal oxynitrides (such as TiN x O y , VN x O y The thin films of ferrite, ferrite, etc. are used as electrode layers and are combined with dense transition metal nitride current collector layers to form supercapacitor electrode materials. However, when these materials are measured by high-scan CV method at 10 V / s, the specific capacitance is still less than 10 mF / cm 2 / μm, which cannot meet the performance requirements of high-throughput molecular detection chips for microelectrodes; on the other hand, studies have shown that materials such as porous molybdenum nitride as electrode layers exhibit excellent specific capacitance characteristics when tested by low-scan CV method, but the internal resistance of this type of material is relatively high, and the specific capacitance value will decrease rapidly with the increase of voltage scan rate. What is particularly fatal is that its electrochemical properties are unstable, and problems such as peeling occur during the test process, which does not meet the stability requirements of biochips.

[0010] Therefore, it is necessary to find a supercapacitor microelectrode material combination to prepare microelectrodes for forming biochips, so as to overcome the deficiencies in the prior art mentioned above. Summary of the invention

[0011] Based on the special combined properties of metal-doped transition metal oxynitrides and transition metal nitrides, the present disclosure proposes a new metal-doped supercapacitor electrode material, a current collector and an adhesion layer growth combination method, which can simultaneously meet the performance requirements of microelectrodes in biochips for high specific capacitance, fast time response and high chemical stability.

[0012] According to a first aspect of the present disclosure, a microelectrode of a biochip is provided. The microelectrode may include: a substrate; a current collector layer formed on the substrate, the current collector layer including a nitride film of a first transition metal; and an electrode layer formed on the current collector layer, the electrode layer including a nitride film of the first transition metal doped with a second metal.

[0013] Preferably, the material of the substrate may include one of Si, Ge, and Group III-V semiconductor materials. Preferably, the Group III-V semiconductor material includes gallium arsenide.

[0014] The microelectrode of the biochip according to the first aspect of the present disclosure may further include: an adhesion layer formed between the substrate and the current collector layer, the adhesion layer including a first transition metal film.

[0015] Preferably, the first transition metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0016] Similarly, preferably, the second metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr. However, the second metal is different from the first transition metal.

[0017] Preferably, the thickness of the first transition metal nitride film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

[0018] Preferably, the first transition metal film has a thickness of 10 to 5000 nm and a resistivity of less than 500 μΩ·cm.

[0019] Preferably, the thickness of the nitride oxide film of the first transition metal doped with the second metal is 10 to 5000 nm.

[0020] In the microelectrode of the biochip according to the first aspect of the present disclosure, in the nitride film of the first transition metal, the stoichiometric ratio of the first transition metal element to the nitrogen element is 0.9-1.1, and wherein the oxygen element as an impurity has a content of less than 15 mol%.

[0021] In the microelectrode of the biochip according to the first aspect of the present disclosure, in the nitride oxide thin film of the first transition metal doped with the second metal, the content of nitrogen element is 25-45 mol %, and the content of oxygen element is 15-35 mol %.

[0022] In the microelectrode of the biochip according to the first aspect of the present disclosure, at the interface between the current collector layer and the electrode layer, the organizational structure of the film gradually changes from dense columnar crystals to porous columnar crystals, thereby gradually transforming the component composition of the film from a nitride film of the first transition metal to a nitride oxide film of the first transition metal doped with a second metal.

[0023] In the microelectrode of the biochip according to the first aspect of the present disclosure, at the interface between the adhesion layer and the current collector layer, the film composition is gradually transformed from the first transition metal film to the nitride film of the first transition metal to form a compound interface.

[0024] In the microelectrode of the biochip according to the first aspect of the present disclosure, in the electrode layer, the lattice of the nitrogen oxide of the first transition metal is used as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton with its nanoscale nitrogen oxide.

[0025] According to a second aspect of the present disclosure, a method for preparing a microelectrode of a biochip is provided. The method may include: providing a substrate; depositing a first transition metal nitride film on the substrate as a current collector layer; and co-depositing a first transition metal nitride film doped with a second metal on the current collector layer as an electrode layer.

[0026] Preferably, the material of the substrate includes one of Si, Ge, and Group III-V semiconductor materials. Preferably, the Group III-V semiconductor material includes gallium arsenide.

[0027] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, the step of depositing a first transition metal nitride film on the substrate as a current collector layer may further include: depositing the first transition metal film on the substrate as an adhesion layer; and depositing the first transition metal nitride film on the adhesion layer as the current collector layer.

[0028] Preferably, the first transition metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0029] Similarly, preferably, the second metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr. However, the second metal is different from the first transition metal.

[0030] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, the step of providing a substrate may further include: cleaning the surface of the substrate using a standard cleaning process.

[0031] Preferably, the thickness of the first transition metal nitride film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

[0032] Preferably, the first transition metal film has a thickness of 10 to 5000 nm and a resistivity of less than 500 μΩ·cm.

[0033] Preferably, the thickness of the nitride oxide film of the first transition metal doped with the second metal is 10 to 5000 nm.

[0034] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, in the nitride film of the first transition metal, the stoichiometric ratio of the first transition metal element to the nitrogen element is 0.9-1.1, and wherein the oxygen element is an impurity and its content is less than 15 mol%.

[0035] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, in the nitride oxide film of the first transition metal doped with the second metal, the content of nitrogen is 25-45 mol % and the content of oxygen is 15-35 mol %.

[0036] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, the step of co-depositing a nitride film of the first transition metal doped with a second metal as an electrode layer on the current collector layer may include: on the nitride film of the first transition metal of the current collector layer, based on a co-deposition process, by gradually adjusting the deposition process parameters, the organizational structure of the film is gradually changed from dense columnar crystals to porous columnar crystals, and the component composition of the film is gradually changed from the nitride film of the first transition metal to the nitride film of the first transition metal doped with the second metal with a rough surface, porous structure, and high specific volume, so as to realize the in-situ continuous growth of the nitride film of the first transition metal of the current collector layer and the nitride film of the first transition metal doped with the second metal of the electrode layer.

[0037] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, the step of depositing the first transition metal nitride film on the adhesion layer as the current collector layer may include: on the first transition metal film of the adhesion layer, based on a deposition process, by gradually adjusting deposition process parameters, the component composition of the film is gradually transformed from the first transition metal film to the nitride film of the first transition metal, thereby forming a compound interface.

[0038] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, in the electrode layer, the lattice of the nitrogen oxide of the first transition metal is used as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton with its nanoscale nitrogen oxide.

[0039] According to a third aspect of the present disclosure, a biochip is provided, which may include the microelectrode according to the first aspect of the present disclosure.

[0040] It should be noted that the biochip described in the present disclosure may be, specifically, a biomolecule detection chip. Preferably, the biochip may be, for example, a nucleic acid sequencing chip, a protein sequencing chip, or an enzyme screening chip.

[0041] In the technical solution disclosed in the present invention, a composite structure supercapacitor electrode design is adopted in which metal-doped transition metal oxynitride is used as an electrode layer, transition metal nitride is used as a current collector layer, and transition metal is used as an adhesion layer. By optimizing the doping component ratio, the form of film growth, and the deposition process parameters, a special electrode film component ratio, surface morphology, and crystallographic orientation are obtained. Specifically, for metal-doped transition metal oxynitride as an electrode layer, its structure is based on a lattice of a transition metal oxynitride (such as TiNO) as a basic skeleton, and another transition metal (such as Mo) is solid-dissolved or dispersed in the above-mentioned basic skeleton in the form of its nanoscale oxynitride (MoNO), thereby having the following advantages:

[0042] a. The microelectrode obtained according to the technology disclosed in the present invention has a high scanning rate of 10V / s cyclic voltammetry (CV) measurement of more than 20mF / cm 2 The high specific capacitance of / μm ensures that the voltage driving capability and stability can meet the needs of high-throughput biochips;

[0043] b. The microelectrode obtained according to the technology disclosed in the present invention can maintain high structural stability and electrochemical stability in saline solution when in contact with organic solvents. After 2000 CV cycle tests, it still has a specific capacitance retention rate of more than 80%, and the electrode film is in good condition after the cycle, meeting the requirements of long-term cyclic charging and discharging of biochips during service.

[0044] Those skilled in the art should understand that in the formation process of semiconductor chips and devices, thin films of various materials can be deposited by using processes such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). More specifically, for PVD, it can be DC, medium frequency and radio frequency magnetron sputtering, laser pulse deposition, etc. In particular, according to the technical solution disclosed in the present invention, at the interface between the transition metal adhesion layer and the transition metal nitride current collector, by changing the thin film deposition process parameters such as the sputtering atmosphere, the composition is gradually changed from the transition metal to its nitride, forming a compound interface, and improving the bonding force at the interface. On the other hand, by gradually adjusting the process parameters such as the sputtering working pressure at the interface between the current collector layer and the electrode layer, the growth mode of the film is regulated, and the organizational structure at the interface is gradually changed from dense columnar crystals to porous columnar crystals, thereby improving the bonding force between the interfaces, improving the stability of the composite structure electrode, and extending the chip life.

[0045] The raw materials used in the technical solution of the present invention to prepare the microelectrodes are common commercial materials and the preparation process is simple, so the cost is low and the productivity is strong, which has the basis for large-scale mass production.

[0046] The purpose of the present disclosure is to provide a composite structure supercapacitor electrode and a new preparation technology for a biochip, which has a metal-doped transition metal oxynitride as an electrode layer, a transition metal nitride as a current collector layer, and a transition metal as an adhesion layer. The performance of the material is tailored by simply changing the proportion of the doping components and the thin film deposition process parameters, and the in-situ continuous growth of a high specific capacitance metal-doped transition metal oxynitride electrode layer on a high conductivity and dense transition metal nitride current collector layer is achieved, and an outstanding effect of synergistic optimization of specific capacitance value and time response characteristics is obtained, and excellent electrochemical stability is guaranteed. The technical process is simple and easy, low cost, a wide range of thin film deposition technology options, and strong process applicability, providing a realistic and feasible new solution for improving the comprehensive performance indicators of microelectrodes such as specific capacitance, time response characteristics and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which like elements are numbered in a similar manner, and in which:

[0048] Figure 1 This is a schematic diagram of the principle of applying a nanopore-based biomolecule detection chip to biomolecule detection.

[0049] Figure 2 It is a schematic diagram of the structure of the microelectrode of the biochip according to an embodiment of the present disclosure.

[0050] Figure 3 It is a schematic flow chart of a method for preparing microelectrodes of a biochip according to an embodiment of the present disclosure.

[0051] Figure 4 It is a cyclic voltammetry curve of the Ti adhesion layer\TiN current collector\Ti-Mo-NO electrode prepared according to Example 1 at different scanning rates.

[0052] Figure 5 The Ti adhesion layer\TiN current collector\Ti-Mo-NO electrode prepared according to Example 1 and the Ti adhesion layer\TiN current collector\TiN electrode prepared according to Comparative Example 1 are x O y Variation curve of specific capacitance of the electrode with scan rate.

[0053] Figure 6 The Ti adhesion layer\TiN current collector\Ti-Mo-NO electrode prepared according to Example 1 and the Ti adhesion layer\TiN current collector\TiN electrode prepared according to Comparative Example 1 are x O y Comparison of potential step transient measurements of electrodes.

[0054] Figure 7 It is a cyclic voltammetry curve of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared according to Example 2 at different scan rates.

[0055] Figure 8 It is a cyclic voltammetry curve of the Mo adhesion layer\MoN current collector\Mo-NO electrode prepared according to Comparative Example 2 at different scanning rates.

[0056] Fig. 9 It is a curve showing the change of specific capacitance of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared according to Example 2 and the Mo adhesion layer\MoN current collector\Mo-NO electrode prepared according to Comparative Example 2 as a function of scan rate.

[0057] Fig.10These are metallographic photographs of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared according to Example 2 and the Mo adhesion layer\MoN current collector\Mo-NO electrode prepared according to Comparative Example 2. DETAILED DESCRIPTION

[0058] The technical solution of the present disclosure is further described in detail below through embodiments and in combination with the accompanying drawings, but the present disclosure is not limited to the following embodiments.

[0059] Those skilled in the art should understand that although ordinal numbers such as "first" and "second" are used in the present disclosure to describe various regions, layers, parts, elements or substances, these regions, layers, parts, elements or substances should not be limited by these ordinal numbers. These ordinal numbers are only used to distinguish one region, layer, part, element or substance from another region, layer, part, element or substance. Therefore, the first region, layer, part, element or substance described below can be interchangeably named as the second region, layer, part, element or substance; similarly, the second region, layer, part, element or substance can also be interchangeably named as the first region, layer, part, element or substance, and such naming does not deviate from the teachings of the present disclosure and does not imply an actual necessary order unless explicitly specified in the text.

[0060] In addition, relative terms such as "upper", "lower", "top", "bottom" and the like are also used in the present disclosure to illustrate the relative relationship between an element, module, part and another element, module, part as shown in the figure. It should be understood by those skilled in the art that such relative terms are intended to include different orientations of elements, modules, parts other than the orientations described in the figure. For example, if the elements in the figure are turned over, the elements originally described as being on the "upper" side of other elements will be located on the "lower" side of the other elements. Therefore, based on the specific orientation of the accompanying drawings, the exemplary term "upper" can actually include the orientations of "lower" and "upper". Similarly, if an element in the figure is turned over, the elements described as being "lower" of other elements will be located "on" of the other elements. Therefore, the exemplary term "lower" can also include the orientations of "upper" and "lower". Similarly, the relative relationship of "top" and "bottom" can be explained. In short, such relative terms do not imply an absolute positional relationship unless explicitly specified in the text.

[0061] In addition, those skilled in the art should understand that terms such as "including" or "having" in the present disclosure are intended to indicate the existence of features, numbers, steps, behaviors, components, or a combination thereof listed in the present disclosure, and do not exclude the possibility of the existence or addition of one or more other features, numbers, steps, behaviors, components, or a combination thereof.

[0062] The technical solution disclosed in this disclosure is applied to the field of molecular detection, including nanopore-based gene sequencing (nucleic acid sequencing) chips, protein sequencing chips and other biomacromolecule detection chips, which are core components for converting nucleic acids, proteins and other biomacromolecules or their sequence signals into current signals. The microelectrode realized by the technology disclosed in this disclosure can provide the voltage driving force required by the detection chip, which is crucial to improving the flux of the detection chip.

[0063] Figure 1 This is a schematic diagram of the principle of using a nanopore-based biomolecule detection chip in biomolecule detection. Figure 1 As shown, each chip unit includes, for example, an ASIC (Application Specific Integrated Circuit) substrate, a microelectrode layer located on the substrate, and a micropore sidewall covering the substrate and the microelectrode layer. Among them, a micropore from the top to the surface of the microelectrode layer is opened in the middle of the micropore sidewall, and the micropore sidewall can be composed of an electrode material, a hydrophilic material, a lipophilic material, or a combination thereof. The working principle of the chip is as follows: the micropore and its flow path are filled with a salt solution, and the opening at the top of the micropore is covered with a biofilm, and the biofilm is inlaid with a nanopore biochemical system. By applying different voltages between the microelectrode and the common electrode realized by the technology disclosed in the present invention, a voltage difference is formed inside the detection chip unit, thereby driving the charged ions in the salt solution through the nanopore to form a microcurrent. When the biological macromolecule to be detected or its sequence passes through the nanopore, it will interact with the nanopore signal detection area to generate a characteristic microcurrent. The characteristics of the characteristic microcurrent, such as intensity, duration, etc., are determined by the characteristics of the biological macromolecule to be detected or its sequence or its modifier, such as the type of base carried by the nucleotide, the type of amino acid residue in the protein sequence, the nature of the nucleotide or protein modifier, etc. This characteristic microcurrent is conducted to the ASIC substrate via the microelectrode layer and can be detected by a semiconductor measurement chip connected to the electrode, thereby achieving the purpose of biological macromolecule detection such as nucleic acid sequencing and protein sequencing.

[0064] The present disclosure provides a microelectrode of a biochip. Those skilled in the art should recognize that the biochip described herein, more specifically, can be a biomolecule detection chip. Preferably, the biochip can be, for example, a nucleic acid sequencing chip, a protein sequencing chip, or an enzyme screening chip.

[0065] Figure 2 Schematic diagram of the structure of the microelectrode of the biochip according to the embodiment of the present disclosure. Figure 2 As shown in , the microelectrode of the biochip according to the embodiment of the present disclosure may include: a substrate 210 , a current collector layer 230 and an electrode layer 240 .

[0066] The substrate 210 may be Figure 1The ASIC substrate shown in FIG. The material of the substrate 210 may include one of silicon (Si), germanium (Ge), and III-V semiconductor materials. For example, the III-V semiconductor material may be gallium arsenide (GaAs).

[0067] The current collector layer 230 is formed on the substrate 210. The current collector layer 230 includes a nitride thin film of a first transition metal. The first transition metal here may include at least one of titanium (Ti), vanadium (V), tantalum (Ta), molybdenum (Mo), hafnium (Hf), and zirconium (Zr).

[0068] According to a preferred embodiment of the present disclosure, the thickness of the first transition metal nitride film of the current collector layer 230 is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm. Moreover, in the first transition metal nitride film of the current collector layer 230, the stoichiometric ratio of the first transition metal element to the nitrogen (N) element is 0.9 to 1.1, and the oxygen (O) element is an impurity, and the content is less than 15 mol%.

[0069] Those skilled in the art should understand that the current collector layer 230 described here is formed on the substrate 210. In one case, the current collector layer 230 is directly formed on the substrate 210. In another case, other regions or layers are first formed on the substrate 210, and then the current collector layer 230 is formed. In other words, the term "A is above B" described in the present disclosure is not limited to the case where A and B are directly and closely connected up and down, but only indicates the approximate up and down positional relationship between A and B.

[0070] According to a preferred embodiment of the present disclosure, optionally, the microelectrode of the biochip according to the present disclosure may further include an adhesion layer 220. The adhesion layer 220 is formed between the substrate 210 and the current collector layer 230. That is, in one implementation, the adhesion layer 220 is directly formed on the substrate 210, and the current collector layer 230 is directly formed on the adhesion layer 220. The adhesion layer 220 includes a first transition metal film. As mentioned above, the first transition metal here may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0071] According to a preferred embodiment of the present disclosure, the first transition metal film of the adhesion layer 220 has a thickness of 10 to 5000 nm and a resistivity of less than 500 μΩ·cm.

[0072] The electrode layer 240 is formed on the current collector layer 230. The electrode layer 240 includes a nitride oxide film of a first transition metal doped with a second metal. The second metal mentioned here can also include at least one of Ti, V, Ta, Mo, Hf, and Zr. However, the second metal is different from the first transition metal.

[0073] According to a preferred embodiment of the present disclosure, the thickness of the first transition metal oxynitride film doped with the second metal of the electrode layer 240 is 10 to 5000 nm. Moreover, in the first transition metal oxynitride film doped with the second metal of the electrode layer 240, the content of nitrogen is 25 to 45 mol%, and the content of oxygen is 15 to 35 mol%.

[0074] An important feature of the microelectrode according to the embodiment of the present disclosure is that, at the interface between the current collector layer 230 and the electrode layer 240, the organizational structure of the film gradually changes from dense columnar crystals to porous columnar crystals, thereby gradually changing from a nitride film of the first transition metal to a nitride oxide film of the first transition metal doped with the second metal in terms of the component composition of the film.

[0075] Similarly, optionally, at the interface between the adhesion layer 220 and the current collector layer 230 , the composition of the film is gradually transformed from the first transition metal film to the nitride film of the first transition metal, forming a compound interface.

[0076] Another important feature of the microelectrode according to the embodiment of the present disclosure is that, in the electrode layer 240, the lattice of the nitride oxide of the first transition metal is used as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton as its nano-scale nitride oxide.

[0077] Accordingly, the present disclosure provides a method for preparing a microelectrode of a biochip. As described above, the biochip described herein, more specifically, can be a biomolecule detection chip. Preferably, the biochip can be, for example: a nucleic acid sequencing chip, a protein sequencing chip, or an enzyme screening chip.

[0078] In general, the present disclosure proposes a supercapacitor material of a composite structure of a transition metal adhesion layer / nitride current collector layer / metal-doped transition metal oxynitride electrode layer and a preparation method. In the preparation method, it is necessary to clean and remove impurities and dirt on the surface of the substrate. Optionally, a layer of transition metal is deposited on the surface of the substrate as an adhesion layer, that is, the adhesion layer is an optional layer. Then, a layer of transition metal or its nitride film with high density and high conductivity is deposited on the surface of the adhesion layer as an electron transport current collector material. Finally, by gradually adjusting the co-deposition process parameters, the composition and organizational structure of the film components are gradually changed, and a layer of metal-doped transition metal oxynitride film with a porous structure and high specific capacitance is epitaxially grown on the current collector as an electrode material.

[0079] Figure 3 FIG. 1 is a schematic diagram of a method for preparing a microelectrode of a biochip according to an embodiment of the present disclosure. Figure 3As shown in the flowchart, the method for preparing the microelectrode of the biochip according to the embodiment of the present disclosure may start from step S310.

[0080] In step S310 , a substrate is provided.

[0081] Step S310 may further include: cleaning the surface of the substrate using a standard cleaning process to remove impurities and dirt on the surface of the substrate.

[0082] The substrate may be made of one of Si, Ge, and III-V semiconductor materials. The III-V semiconductor may be gallium arsenide or the like.

[0083] In step S320 , a first transition metal (M) nitride (MN) thin film is deposited on the substrate as a current collector layer.

[0084] As mentioned above, an adhesion layer may be formed between the substrate and the current collector layer. Therefore, in a preferred embodiment of the present disclosure, optionally, step S320 may further include: depositing a first transition metal (M) thin film on the substrate as an adhesion layer; and then depositing a first transition metal nitride (MN) thin film on the adhesion layer as a current collector layer.

[0085] In step S330 , a first transition metal (M) oxynitride (MDNO) thin film doped with a second metal (D) is co-deposited on the current collector layer as an electrode layer.

[0086] From a process perspective, the above steps can be described as: depositing a first transition metal (M) adhesion layer, then depositing a first transition metal nitride (MN) current collector layer, and finally co-depositing a first transition metal (M) oxynitride (MDNO) electrode layer doped with a second metal (D).

[0087] Specifically, the thin film deposition and co-deposition process is adopted to achieve effective control of the mechanisms such as atomic diffusion and nucleation growth by regulating the process parameters: first, a first transition metal M thin film with a smooth surface, high density, and high conductivity (low resistivity) is deposited on the substrate provided (and cleaned) in step S310 as an adhesion layer; then, a MN thin film is deposited on the surface of the above-mentioned adhesion layer as a current collector material, and during deposition, the process parameters such as the sputtering atmosphere are adjusted to make the film composition gradually change from the transition metal M of the adhesion layer to the MN of the current collector layer to form a compound interface; then, based on the co-deposition process, by gradually adjusting the deposition process parameters such as the sputtering working pressure, the film component composition and organizational structure are gradually changed from the MN thin film to the MDNO thin film electrode layer with a rough surface, porous structure, and high specific capacitance, so as to achieve in-situ continuous growth of the MN current collector layer and the MDNO electrode layer. After the M / MN / MDNO composite structure electrode is qualified through the physical and chemical performance test (metallographic structure, electrochemical performance, electrochemical stability), it is patterned by photolithography or mask plate.

[0088] The M film as the adhesion layer has a thickness of 10 to 5000 nm and a resistivity of less than 500 μΩ·cm.

[0089] The thickness of the MN film used as the current collector layer is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0090] The thickness of the MDNO film used as the electrode layer is 10 to 5000 nm.

[0091] The process parameters include target-substrate distance, ratio of argon to nitrogen, M target sputtering power, D target sputtering power, substrate temperature, working gas pressure, substrate bias and other process parameters. The parameters may vary depending on different process machines, but should not affect the essence and spirit of the invention disclosed and claimed for protection in this disclosure.

[0092] The sputtering method is used, and the process parameters for depositing the adhesion layer are as follows: target-substrate distance is 20-100 mm; sputtering power: 100-1000 W; substrate temperature is room temperature to 400° C.; argon working pressure is 0.2 to 2 Pa; substrate bias is 0 to -400 V; and sputtering time is 5 to 500 minutes.

[0093] The sputtering method was used to deposit the collector layer. The process parameters were as follows: target-substrate distance was 20-100 mm; Ar:N 2 =(10-200):(1-20)sccm; sputtering power: 100-1000W; substrate temperature is room temperature to 400°C; working gas pressure is 0.2 to 2Pa; substrate bias is -50 to -400V; sputtering time: 5 to 500 minutes.

[0094] The sputtering method is used, and the process parameters for depositing the electrode layer are as follows: the target-substrate distance is 20-100 mm; Ar:N 2 =(10-200):(1-20)sccm; M target sputtering power: 100-1000W; D target sputtering power: 100-1000W; substrate temperature is room temperature ~ 400℃; working gas pressure is 0.4 ~ 2Pa; substrate bias is 0 ~ -400V; sputtering time: 5-500 minutes.

[0095] The M in the MN (first transition metal nitride) described above is one or more transition metals such as Ti, Mo, V, Ta, Zr, Hf, etc., the stoichiometric ratio of M to N in the nitride (M:N) is between 0.9 and 1.1, and the O impurity content is less than 15 mol%. The composition of the MDNO (nitride of the first transition metal doped with the second metal) described above is affected by factors such as the preparation conditions of the film, gas, target material and precursor purity, wherein M and D are both one of the transition metals such as Ti, Mo, V, Ta, Zr, Hf, etc., but D is different from M, and the N content in the electrode material is between 25-45 mol%, and the O content is between 15-35 mol%.

[0096] Traditional thin film deposition processes include physical vapor deposition (PVD), including vacuum evaporation, sputtering coating, arc plasma coating, etc.

[0097] In the preparation method disclosed in the present invention, chemical vapor deposition (CVD) or atomic layer deposition (ALD) can also be used to deposit an adhesion layer / current collector layer / electrode layer on the surface of the cleaned substrate.

[0098] The composite structure supercapacitor material of transition metal adhesion layer / transition metal nitride current collector layer / metal-doped transition metal oxynitride electrode layer and its preparation technology have very good application value in the field of high-throughput molecular detection chips. Compared with other manufacturing technologies, this technology has the advantages of simple and easy process, low cost, a wide range of thin film deposition technology options, and strong process applicability.

[0099] It should be emphasized here that in the preparation method according to the embodiment of the present disclosure, step S330 can be specifically implemented as follows: on the first transition metal nitride film of the current collector layer, based on the co-deposition process, by gradually adjusting the deposition process parameters, the organizational structure of the film is gradually changed from dense columnar crystals to porous columnar crystals, and the component composition of the film is gradually changed from the first transition metal nitride film to a first transition metal doped with the second metal with a rough surface, porous structure, and high specific volume. The nitride film, thereby achieving the in-situ continuous growth of the first transition metal nitride film of the current collector layer and the nitride film of the first transition metal doped with the second metal of the electrode layer.

[0100] Similarly, also optionally, in step S320, the step of depositing the first transition metal nitride film on the adhesion layer as the current collector layer can be specifically implemented as follows: on the first transition metal film of the adhesion layer, based on the deposition process, by gradually adjusting the deposition process parameters, the component composition of the film is gradually transformed from the first transition metal film to the first transition metal nitride film, thereby forming a compound interface.

[0101] In addition, as described above, in the process of forming the electrode layer in step S330, the lattice of the nitride oxide of the first transition metal is used as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton with its nano-scale nitride oxide.

[0102] It should be noted that in the foregoing description, in the following description of the embodiments and comparative examples, and in the accompanying drawings, “-NO”, “-ON” and “-N x O y " is used to represent nitrogen oxides (oxynitride or oxy-nitride, or oxynitride). Those skilled in the art should understand that the meanings of these expressions for nitrogen oxides are consistent. Moreover, "-N x O y " In the above description, there is no particular restriction on the values ​​of x and y, and they can be any integer values ​​in theory. In other words, in such a representation, the order of N and O is not critical, and the ratio of N to O is not critical (unless otherwise specified in the specification or in the examples).

[0103] The following is a comparison experiment of the effects of a group of embodiments and comparative examples.

[0104] Embodiment 1:

[0105] In this embodiment, a single crystal silicon substrate is selected as the substrate, and the substrate is cleaned using the semiconductor industry standard RCA cleaning process. DC reactive magnetron sputtering is used, the target material is titanium (Ti) metal, and the process parameters are: the background vacuum degree is 5×10 -4 Pa, target substrate distance of 125mm, substrate temperature of 350℃, working pressure of 0.4Pa, Ar gas flow rate of 30sccm, and deposition time of 5 minutes, a Ti film with a thickness of 30nm, a resistivity of 55.6μΩ·cm, and a smooth surface is first deposited on the substrate surface as an adhesion layer. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance of 125mm, working pressure of 0.4Pa, Ar:N 2=30:2.5sccm, substrate negative bias voltage of -100V, deposition time of 20 minutes, a TiN film with a thickness of 70.1nm, resistivity of 37.1μΩ·cm, smooth surface and high density is deposited on the surface of the adhesion layer as the current collector layer, and by adjusting the sputtering atmosphere and gradually introducing N 2 The gas was used to gradually change the composition of the adhesion layer and the current collector interface, that is, gradually change from Ti metal to TiN. Then, through co-deposition, the target materials were titanium (Ti) metal and molybdenum (Mo) metal, and the co-deposition process parameters were gradually adjusted to: the target-substrate distance of the titanium target was 125mm, the target-substrate distance of the molybdenum target was 115mm, and the Ar:N 2 =20:8sccm, titanium target sputtering power is 200W, molybdenum target sputtering power is 150W, substrate temperature is 350℃, working gas pressure is 1.5Pa, sputtering time is 20 minutes, the organizational structure and composition are gradually changed on the TiN film, and a layer of 286nm thick, resistivity is 11249μΩ·cm, rough surface, nano-micropore Ti-Mo-NO film is grown in situ as the electrode layer. Using a three-electrode test system, the working electrode is Ti-Mo-NO, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is a KCl solution. The cyclic voltammetry curve is tested using an electrochemical workstation, such as Figure 4 As shown. Figure 4 It can be seen that the curve has good rectangularity at high scan rate, indicating that the Ti adhesion layer\TiN current collector\Ti-Mo-NO electrode prepared in this embodiment has small internal resistance and excellent rate characteristics.

[0106] Comparative Example 1:

[0107] In this comparative example, a single crystal silicon substrate was selected as the substrate, and the substrate was cleaned using the semiconductor industry standard RCA cleaning process. DC reactive magnetron sputtering was used, and the target material was titanium (Ti) metal. The process parameters were: the background vacuum was 5×10 -4 Under the conditions of target-substrate distance of 125 mm, substrate temperature of 350 °C, working pressure of 0.4 Pa, Ar gas flow rate of 30 sccm, and deposition time of 5 minutes, a Ti film with a thickness of 30 nm, a resistivity of 55.6 μΩ·cm, and a smooth surface is first deposited on the substrate surface as an adhesion layer. Then, under the process parameters of target-substrate distance of 125 mm, Ar:N 2=30:2.5sccm, sputtering power of 200W, substrate temperature of 350℃, working pressure of 0.4Pa, substrate bias of -100V, sputtering time of 20 minutes, first deposit a layer of TiN thin film with a thickness of 70.1nm, resistivity of 37.1μΩ·cm, smooth surface and high density as the current collector layer on the substrate surface. Then adjust the deposition process parameters, the process parameters are: target substrate distance of 125mm, Ar:N 2 =30:2.5sccm, sputtering power of 200W, substrate temperature of 350℃, working pressure of 1.6Pa, sputtering time of 20 minutes, a layer of TiN with a thickness of 265.5nm and a resistivity of 21327μΩ·cm, a rough surface and nano-pores was grown on the TiN film. x O y The film serves as the electrode layer.

[0108] Comparison between Example 1 and Comparative Example 1:

[0109] like Figure 5 As shown, compared with the Ti adhesion layer\TiN current collector\TiN prepared in Comparative Example 1 x O y The specific capacitance of the Ti adhesion layer, TiN current collector, and Ti-Mo-NO electrode prepared in Example 1 (at the same scan rate) is increased by 1.5 to 1.8 times, and the specific capacitance is still more than 58 mF / cm at a scan rate of 10 mV / s. 2 / μm. Using the controlled potential step transient measurement method, the working electrode is Ti-Mo-NO, the counter electrode is Ag\AgCl electrode, the electrolyte is KCl solution, and a 20KΩ series resistor is used. The current response curve is tested using the standard measurement method to measure the current decay time. The results are as follows Figure 6 As shown. Figure 6 It can be seen that the discharge voltage drop rate of the Ti adhesion layer\TiN current collector\Ti-Mo-NO electrode prepared in Example 1 is significantly lower than that of the Ti adhesion layer\TiN current collector\TiN in Comparative Example 1. x O y The time it takes for the electrode to drop to 80% of the initial voltage is longer than that of the Ti adhesion layer\TiN current collector\TiN x O y The electrode's time is increased from about 50ms to about 90ms, and the voltage driving capability is significantly improved.

[0110] Embodiment 2:

[0111] In this embodiment, a single crystal silicon substrate is selected as the substrate, and the substrate is cleaned using the semiconductor industry standard RCA cleaning process. DC reactive magnetron sputtering is used, and the target material is vanadium (V) metal. The process parameters are: the background vacuum is less than 10- 4 Pa, target substrate distance of 60mm, substrate temperature of 450℃, working pressure of 0.5Pa, Ar=50sccm, and deposition time of 5 minutes, a V film with a thickness of 40nm, a resistivity of 65.5μΩ·cm, and a smooth surface is first deposited on the substrate surface as an adhesion layer. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance of 60mm, substrate temperature of 450℃, working pressure of 0.5Pa, Ar:N 2 =50:10sccm, and the deposition time is 20 minutes. On the surface of the adhesion layer, a VN thin film with a thickness of 65nm, a resistivity of 416.5μΩ·cm, a smooth surface and high density is deposited as the current collector layer. By adjusting the sputtering atmosphere and gradually introducing N 2 The gas was used to gradually change the composition of the adhesion layer and the current collector interface, that is, gradually change from V metal to VN. Then, through co-deposition, the targets were vanadium (V) metal and molybdenum (Mo) metal, and the co-deposition process parameters were gradually adjusted to: the target-substrate distance of the vanadium target was 60mm, the target-substrate distance of the molybdenum target was 80mm, and the Ar:N 2 =20:4sccm, vanadium target sputtering power is 200W, molybdenum target sputtering power is 150W, substrate temperature is 450℃, working gas pressure is 1.5Pa, sputtering time is 20 minutes, the organization structure and composition are gradually changed on the VN film, and a layer of V-Mo-ON film with a thickness of 300nm, a resistivity of 10406μΩ·cm, a rough surface and nano-pores is grown in situ as the electrode layer. Using a three-electrode test system, the working electrode is V-Mo-NO, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is a KCl solution. The cyclic voltammetry curve is tested using an electrochemical workstation, such as Figure 7 As shown. Figure 7 It can be seen that the curve has good rectangularity at high scan rate, indicating that the V adhesion layer\VN current collector\V-Mo-NO electrode prepared in this embodiment has small internal resistance and excellent rate characteristics.

[0112] Comparative Example 2:

[0113] In this comparative example, a single crystal silicon substrate is selected as the substrate, and the substrate is cleaned using the semiconductor industry standard RCA cleaning process. DC reactive magnetron sputtering is used, and the target material is molybdenum (Mo) metal. The process parameters are: the background vacuum is less than 10 - 4Pa, target substrate distance of 60mm, substrate temperature of 350℃, working pressure of 0.5Pa, Ar=50sccm, and deposition time of 5 minutes, a Mo film with a thickness of 40nm and a resistivity of 55.5μΩ·cm and a smooth surface is first deposited on the substrate surface as an adhesion layer. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance of 60mm, substrate temperature of 350℃, working pressure of 0.5Pa, Ar:N 2 =50:10sccm, deposition time of 20 minutes, a MoN thin film with a thickness of 65nm, a resistivity of 178.5μΩ·cm, a smooth surface and high density is deposited on the surface of the above adhesion layer as the current collector layer. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance is 80mm, Ar:N 2 =20:4sccm, sputtering power of 150W, substrate temperature of 350℃, working pressure of 1.5Pa, sputtering time of 20min, a layer of MoN with a thickness of 300nm and a resistivity of 13250μΩ·cm, a rough surface and nano-micropores was grown in situ on the MoN film. x O y The film is used as the electrode layer. Using a three-electrode test system, the working electrode is Mo-NO, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is a KCl solution. The cyclic voltammetry curve is tested using an electrochemical workstation, as shown in Figure 8 shown.

[0114] Comparison of Example 2 and Comparative Example 2:

[0115] like Fig. 9 As shown, at the same scan rate, the Mo adhesion layer\MoN current collector\MoN prepared in Comparative Example 2 x O y The specific capacitance of the electrode is slightly higher than that of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared in Example 2. At a scan rate of 10 mV / s, the specific capacitance of both electrodes can exceed 45 mF / cm 2 / μm. However, Fig.10 As shown, the Mo adhesion layer\MoN current collector\MoN prepared in Comparative Example 2 x O y After the electrochemical cyclic voltammetry test, the electrode suffered from severe corrosion, and the film peeled off from the surface of the silicon substrate; while the V adhesion layer\VN current collector\V-Mo-NO electrode prepared in Example 2 still maintained a smooth and complete surface state after the electrochemical cyclic voltammetry test, indicating that the addition of the V element greatly improved the corrosion resistance of the electrode.

[0116] The present disclosure also proposes a biochip. The biochip may include the microelectrode according to any of the previous embodiments of the present disclosure. As mentioned above, the biochip described here, more specifically, may be a biomolecule detection chip. Preferably, the biochip may be, for example: a nucleic acid sequencing chip, a protein sequencing chip, or an enzyme screening chip.

[0117] The implementation methods of the present disclosure are not limited to the above-mentioned embodiments. Without departing from the spirit and scope of the present disclosure, ordinary technicians in this field can make various changes and improvements to the present disclosure in form and details, and these are considered to fall within the protection scope of the present disclosure.

Claims

1. A microelectrode of a biochip, characterized in that: include: substrate; A current collector layer is formed on the substrate, wherein the current collector layer comprises a nitride thin film of a first transition metal; An electrode layer is formed on the current collector layer, the electrode layer comprising a nitride film of the first transition metal doped with a second transition metal, wherein on the nitride film of the first transition metal of the current collector layer, based on a co-deposition process, target materials are respectively the first transition metal and the second transition metal, and by gradually adjusting deposition process parameters, in-situ continuous growth of the nitride film of the first transition metal doped with the second transition metal of the electrode layer is achieved on the nitride film of the first transition metal of the current collector layer, wherein in the electrode layer, the nitride lattice of the first transition metal is used as a basic skeleton, and the second transition metal is solid-dissolved or dispersed in the basic skeleton in the form of its nanoscale nitride.

2. The microelectrode of the biochip according to claim 1, characterized in that: The material of the substrate includes one of Si, Ge, and Group III-V semiconductor materials.

3. The microelectrode of the biochip according to claim 2, characterized in that: The Group III-V semiconductor material includes gallium arsenide.

4. The microelectrode of the biochip according to claim 1, characterized in that: Further including: An adhesion layer is formed between the substrate and the current collector layer, and the adhesion layer includes a first transition metal film.

5. The microelectrode of the biochip according to claim 1, characterized in that: The first transition metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr.

6. The microelectrode of the biochip according to claim 5, characterized in that: The second transition metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr, and the second transition metal is different from the first transition metal.

7. The microelectrode of the biochip according to claim 1, characterized in that: The thickness of the first transition metal nitride film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

8. The microelectrode of the biochip according to claim 4, characterized in that: The thickness of the first transition metal film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

9. The microelectrode of the biochip according to claim 1, characterized in that: The thickness of the nitride oxide film of the first transition metal doped with the second transition metal is 10-5000 nm.

10. The microelectrode of the biochip according to claim 1, characterized in that: In the first transition metal nitride film, the stoichiometric ratio of the first transition metal element to the nitrogen element is 0.9-1.1, and the oxygen element is an impurity with a content of less than 15 mol%.

11. The microelectrode of the biochip according to claim 1, characterized in that: In the oxynitride film of the first transition metal doped with the second transition metal, the content of nitrogen is 25-45 mol %, and the content of oxygen is 15-35 mol %.

12. The microelectrode of a biochip according to claim 1, characterized in that: At the interface between the current collector layer and the electrode layer, the organizational structure of the film gradually changes from dense columnar crystals to porous columnar crystals, thereby gradually changing the component composition of the film from a nitride film of the first transition metal to a nitride oxide film of the first transition metal doped with a second transition metal.

13. The microelectrode of the biochip according to claim 4, characterized in that: At the interface between the adhesion layer and the current collector layer, the composition of the film is gradually transformed from the first transition metal film to the nitride film of the first transition metal, forming a compound interface.

14. A method for preparing a microelectrode of a biochip, characterized in that: include: providing a substrate; Depositing a first transition metal nitride thin film on the substrate as a current collector layer; A nitride oxide film of the first transition metal doped with a second transition metal is co-deposited on the current collector layer as an electrode layer, wherein, on the nitride film of the first transition metal of the current collector layer, based on a co-deposition process, target materials are respectively the first transition metal and the second transition metal, and by gradually adjusting deposition process parameters, in-situ continuous growth of the nitride oxide film of the first transition metal doped with the second transition metal of the electrode layer is achieved on the nitride film of the first transition metal of the current collector layer, wherein in the electrode layer, the nitride oxide lattice of the first transition metal is used as a basic skeleton, and the second transition metal is solid-dissolved or dispersedly distributed in the basic skeleton in the form of its nanoscale nitride oxide.

15. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The material of the substrate includes one of Si, Ge, and Group III-V semiconductor materials.

16. The method for preparing a microelectrode of a biochip according to claim 15, characterized in that: The Group III-V semiconductor material includes gallium arsenide.

17. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The step of depositing a first transition metal nitride film on the substrate as a current collector layer further comprises: depositing a first transition metal thin film as an adhesion layer on the substrate; A nitride thin film of the first transition metal is deposited on the adhesion layer as the current collector layer.

18. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The first transition metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr.

19. The method for preparing a microelectrode of a biochip according to claim 18, characterized in that: The second transition metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr, and the second transition metal is different from the first transition metal.

20. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The step of providing a substrate further includes: cleaning the surface of the substrate using a standard cleaning process.

21. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The thickness of the first transition metal nitride film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

22. The method for preparing a microelectrode of a biochip according to claim 17, characterized in that: The thickness of the first transition metal film is 10-5000 nm, and the resistivity is less than 500 μΩ·cm.

23. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The thickness of the nitride oxide film of the first transition metal doped with the second transition metal is 10-5000 nm.

24. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: In the first transition metal nitride film, the stoichiometric ratio of the first transition metal element to the nitrogen element is 0.9-1.1, and the oxygen element is an impurity with a content of less than 15 mol%.

25. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: In the oxynitride film of the first transition metal doped with the second transition metal, the content of nitrogen is 25-45 mol %, and the content of oxygen is 15-35 mol %.

26. The method for preparing a microelectrode of a biochip according to claim 14, characterized in that: The step of co-depositing a nitride oxide film of the first transition metal doped with a second transition metal as an electrode layer on the current collector layer comprises: On the first transition metal nitride film of the current collector layer, based on the co-deposition process, by gradually adjusting the deposition process parameters, the organizational structure of the film is gradually changed from dense columnar crystals to porous columnar crystals, and the component composition of the film is gradually changed from the first transition metal nitride film to the first transition metal doped with the second transition metal nitride oxide film with a rough surface, porous structure and high specific volume, so that the in-situ continuous growth of the first transition metal doped with the second transition metal nitride oxide film of the electrode layer is achieved on the first transition metal nitride film of the current collector layer.

27. The method for preparing a microelectrode of a biochip according to claim 17, characterized in that: The step of depositing the first transition metal nitride film on the adhesion layer as the current collector layer comprises: On the first transition metal film of the adhesion layer, based on a deposition process, deposition process parameters are gradually adjusted so that the composition of the film is gradually transformed from the first transition metal film to the nitride film of the first transition metal, thereby forming a compound interface.

28. A biochip, characterized in that: The microelectrode comprises the microelectrode according to any one of claims 1 to 13.

29. The biochip according to claim 28, characterized in that: The biochip is a biomolecule detection chip.

30. The biochip according to claim 29, characterized in that: The biochip is a nucleic acid sequencing chip, a protein sequencing chip or an enzyme screening chip.

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