Metal-doped supercapacitor microelectrode and preparation method therefor, and biochip

Abstract

Disclosed are a metal-doped supercapacitor microelectrode and a preparation method therefor, and a biochip. On the basis of special combination properties of metal-doped transition metal oxynitrides and transition metal nitrides, the present disclosure provides a microelectrode for a biochip. The microelectrode may comprise: a substrate; a current collector layer formed on the substrate, wherein the current collector layer comprises a nitride thin film of a first transition metal; and an electrode layer formed on the current collector layer, wherein the electrode layer comprises an oxynitride thin film of the first transition metal doped with a second metal. Optionally, the microelectrode of the present disclosure may further comprise an adhesion layer formed between the substrate and the current collector layer, wherein the adhesion layer comprises a first transition metal thin film. The brand-new method for the growth bonding of a metal-doped supercapacitor electrode material, a current collector and an adhesion layer provided in the present disclosure can simultaneously meet the performance requirements of a microelectrode in a biochip for high specific capacitance, fast time response and high chemical stability.

Description

Metal-doped supercapacitor microelectrode, preparation method thereof, and biochip

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application number CN202410109073.8, filed on January 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to biochip technology, and in particular to a metal-doped supercapacitor microelectrode and a preparation method thereof, as well as a biochip comprising the microelectrode. Background Art

[0004] Biochip technology is a chip-based technology for processing and analyzing biological information. It is widely used in biomolecular detection, including nucleic acid sequencing, protein sequencing, and other biomolecular detection fields, and involves the fabrication of microelectrodes. Supercapacitor materials are widely used in the fabrication of microelectrodes in biochips used in these technologies, due to their high energy density and ultra-long cycle life. Microelectrodes typically consist of electrodes and current collectors. The electrodes charge and discharge charge through energy storage mechanisms, providing voltage drive for the biochemical system. The current collector transports electrons and connects to the charge, discharge, and measurement circuits, providing charge and discharge currents for the electrodes and transmitting characteristic current signals for sequencing and other detection to the measurement chip. When the biomolecule or sequence to be detected passes through the nanopore, it interacts with the nanopore's signal detection area, generating a characteristic microcurrent. The characteristics of this characteristic microcurrent, such as intensity and duration, are determined by the characteristics of the biomolecule or sequence to be detected, or its modifications, such as the type of bases in the nucleotide, the type of amino acid residues in the protein sequence, and the nature of the nucleotide or protein modifications. This characteristic microcurrent can be detected by a semiconductor measurement chip connected to the electrodes, thereby achieving the purpose of biomolecular detection such as nucleic acid sequencing and protein sequencing.

[0005] Nucleic acid sequencing and protein sequencing are cutting-edge technologies. Combined with the technical direction of electrical signal detection, there are currently several areas that require breakthroughs:

[0006] 1. Voltage driving capability of microelectrodes: The throughput of a biochip determines its detection cost and efficiency, which is determined by 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 microelectrode radius be at the micrometer scale or even smaller while still maintaining the required voltage driving capability. The existing microelectrode materials and structures are no longer able to meet this requirement. Structural and material design combined with reasonable processing methods are needed to achieve very high specific capacitance and fast time response (high charge and discharge rate) to achieve the required voltage driving capability.

[0007] 2. Microelectrodes need to work in the solution environment of the biochip, come into contact with the organic solvent required for detection, and require long-term cycle charge and discharge. Therefore, their corrosion resistance and electrochemical stability are very important and largely determine the service life of the biochip;

[0008] 3. Microelectrodes need to be easy to implement in MEMS technology at low cost so that they can be mass-produced.

[0009] Among the above requirements, having high specific capacitance, fast time response and high electrochemical stability is the core technical indicator requirement 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 also 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 still obtain more than 10mF / cm when measured at a high scan rate cyclic voltammetry (CV) higher than 10V / s. 2 / μm specific capacitance value, and can still maintain more than 80% specific capacitance retention after 1000 cycles. This requires the microelectrode used to meet the stringent requirements of high specific capacitance and low resistivity at the same time.

[0010] Currently, 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 exhibit a high sensitivity of more than 10mF / cm when measured by low-scan CV method. 2However, 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 sweep rate. Only at a sweep rate greater than 0.1 V / s, the specific capacitance is lower than 4 mF / 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.

[0011] In recent years, high resistivity porous transition metal oxynitrides (such as TiN x O y , VN x O y Thin films (e.g., nitrides) are used as electrode layers and composited 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 a speed of 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 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 will occur during the test process, which does not meet the stability requirements of biochips.

[0012] 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

[0013] 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, current collector and 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.

[0014] According to a first aspect of the present disclosure, a microelectrode for a biochip is provided. The microelectrode may include: a substrate; a current collector layer formed on the substrate, the current collector layer comprising a first transition metal nitride thin film; and an electrode layer formed on the current collector layer, the electrode layer comprising a first transition metal oxynitride thin film doped with a second metal.

[0015] Preferably, the substrate material may include one of Si, Ge, and Group III-V semiconductor materials, wherein preferably, the Group III-V semiconductor material includes gallium arsenide.

[0016] 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 thin film.

[0017] Preferably, the first transition metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0018] 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.

[0019] Preferably, the thickness of the first transition metal nitride film is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0020] Preferably, the thickness of the first transition metal film is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0021] Preferably, the thickness of the first transition metal oxynitride film doped with the second metal is 10 to 5000 nm.

[0022] In the microelectrode of the biochip according to the first aspect of the present disclosure, 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 as an impurity has a content of less than 15 mol%.

[0023] In the microelectrode of the biochip according to the first aspect of the present disclosure, in the oxynitride 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 %.

[0024] 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.

[0025] 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, forming a compound interface.

[0026] 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 serves as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton in the form of its nanoscale nitrogen oxide.

[0027] According to a second aspect of the present disclosure, a method for preparing a microelectrode for a biochip is provided. The method may include: providing a substrate; depositing a first transition metal nitride thin film on the substrate as a current collector layer; and co-depositing a second metal-doped first transition metal oxynitride thin film on the current collector layer as an electrode layer.

[0028] Preferably, the substrate is made of one of Si, Ge, and Group III-V semiconductor materials, wherein preferably, the Group III-V semiconductor material comprises gallium arsenide.

[0029] 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 a 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.

[0030] Preferably, the first transition metal may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0031] 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.

[0032] 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.

[0033] Preferably, the thickness of the first transition metal nitride film is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0034] Preferably, the thickness of the first transition metal film is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0035] Preferably, the thickness of the first transition metal oxynitride film doped with the second metal is 10 to 5000 nm.

[0036] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, in the first transition metal nitride film, the stoichiometric ratio of the first transition metal element to the nitrogen element is 0.9 to 1.1, and the oxygen element as an impurity has a content of less than 15 mol%.

[0037] In the method for preparing a microelectrode of a biochip according to the second aspect of the present disclosure, in the first transition metal oxynitride film doped with the second metal, the nitrogen content is 25-45 mol %, and the oxygen content is 15-35 mol %.

[0038] 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, thereby realizing 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.

[0039] 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 the deposition process, by gradually adjusting the deposition process parameters, so that 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.

[0040] 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.

[0041] 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.

[0042] It should be noted that the biochip described in the present disclosure can be, specifically, 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.

[0043] In the technical solution disclosed herein, a composite supercapacitor electrode design is adopted, in which a metal-doped transition metal oxynitride is used as the electrode layer, a transition metal nitride is used as the current collector layer, and a transition metal is used as the adhesion layer. By optimizing the doping component ratio, the film growth form, and the deposition process parameters, a unique electrode film component ratio, surface morphology, and crystallographic orientation are obtained. Specifically, for metal-doped transition metal oxynitride as the electrode layer, its structure is based on the lattice of a transition metal oxynitride (such as TiNO) as the 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:

[0044] a. The microelectrode obtained according to the technology disclosed in the present invention has a high scan rate cyclic voltammetry (CV) of more than 20mF / cm 2 The high specific capacitance of / μm ensures the voltage driving capability and stability to meet the needs of high-throughput biochips;

[0045] 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 charge and discharge during service of the biochip.

[0046] 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 adopting 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 thereof is gradually changed from 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 thin 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.

[0047] The raw materials used to prepare the microelectrodes in the technical solution disclosed in the present invention are common commercial materials and the preparation process is simple, so the cost is low and the manufacturability is strong, which provides a basis for large-scale mass production.

[0048] The purpose of the present disclosure is to provide a composite structure supercapacitor electrode and a new preparation technology for biochips, which has metal-doped transition metal oxynitride as an electrode layer, transition metal nitride as a current collector layer, and transition metal as an adhesion layer. By simply changing the ratio of doping components and the thin film deposition process parameters to tailor the performance of the material, the in-situ continuous growth of a high specific capacitance metal-doped transition metal oxynitride electrode layer on a highly conductive and dense transition metal nitride current collector layer is achieved, achieving an outstanding effect of synergistic optimization of specific capacitance value and time response characteristics, and ensuring excellent electrochemical stability. This technical process is simple and easy to implement, low cost, has 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

[0049] 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:

[0050] FIG1 is a schematic diagram showing the principle of applying a nanopore-based biomolecule detection chip to biomolecule detection.

[0051] FIG2 is a schematic structural diagram of a microelectrode of a biochip according to an embodiment of the present disclosure.

[0052] FIG3 is a schematic flow chart of a method for preparing microelectrodes of a biochip according to an embodiment of the present disclosure.

[0053] FIG4 is a cyclic voltammetry graph of the Ti adhesion layer, TiN current collector, and Ti-Mo-NO electrode prepared according to Example 1 at different scan rates.

[0054] Figure 5 shows 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. x O y Variation curve of specific capacitance of the electrode with scan rate.

[0055] Figure 6 shows 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. x O y Comparison chart of potential step transient measurements of electrodes.

[0056] FIG7 is a cyclic voltammogram of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared according to Example 2 at different scan rates.

[0057] FIG8 is a cyclic voltammogram of the Mo adhesion layer\MoN current collector\Mo-NO electrode prepared according to Comparative Example 2 at different scan rates.

[0058] Figure 9 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.

[0059] Figure 10 is a metallographic photograph of the V adhesion layer\VN current collector\V-Mo-NO electrode prepared according to Example 2 (left) and the Mo adhesion layer\MoN current collector\Mo-NO electrode prepared according to Comparative Example 2 (right). DETAILED DESCRIPTION

[0060] The technical solutions of the present disclosure are further described in detail below through examples and in conjunction with the accompanying drawings, but the present disclosure is not limited to the following examples.

[0061] Those skilled in the art will 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. Thus, a first region, layer, part, element, or substance described below can be interchangeably named as a second region, layer, part, element, or substance; similarly, a second region, layer, part, element, or substance can also be interchangeably named as a first region, layer, part, element, or substance. Such naming does not depart from the teachings of the present disclosure and does not imply an actual necessary order unless expressly specified herein.

[0062] In addition, relative terms such as "upper," "lower," "top," and "bottom" are used in this disclosure to illustrate the relative relationship of one element, module, or part to another element, module, or part as shown in the figures. Those skilled in the art will understand that such relative terms are intended to include different orientations of elements, modules, or parts in addition to the orientations described in the figures. For example, if an element in a figure is flipped, an element originally described as being on the "upper" side of another element will be located on the "lower" side of the other element. Therefore, based on the specific orientation of the figure, the exemplary term "upper" can actually include both "lower" and "upper" orientations. Similarly, if an element in a figure is flipped, an element described as being "lower" than another element will be located "above" the other element. Therefore, the exemplary term "lower" can also include both "upper" and "lower" orientations. Similarly, the relative relationship of "top" and "bottom" can be interpreted. In short, such relative terms do not imply an absolute positional relationship unless explicitly specified in the text.

[0063] 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 combinations thereof listed in the present disclosure, and do not exclude the possibility of one or more other features, numbers, steps, behaviors, components or combinations thereof existing or being added.

[0064] The disclosed technology has applications in the field of molecular detection, including nanopore-based gene sequencing (nucleic acid sequencing) chips, protein sequencing chips, and other biomacromolecule detection chips. These chips are core components for converting nucleic acids, proteins, and other biomacromolecules, or their sequence signals, into current signals. The microelectrodes implemented by the disclosed technology can provide the voltage driving force required by the detection chips, which is crucial for improving the throughput of detection chips.

[0065] Figure 1 is a schematic diagram of the principle of applying a nanopore-based biomolecule detection chip to biomolecule detection. As shown in Figure 1, 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 is opened in the middle of the micropore sidewall from the top to the surface of the microelectrode layer, and the micropore sidewall can be composed of electrode material, hydrophilic material and lipophilic material or a combination thereof. The working principle of the chip is as follows: the micropore and its flow path are filled with salt solution, 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 to pass 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 this characteristic microcurrent, such as its intensity and duration, are determined by the properties of the biomacromolecule being tested, its sequence, or its modifications, such as the type of bases in the nucleotide, the type of amino acid residues in the protein sequence, and the nature of the nucleotide or protein modifications. This characteristic microcurrent is conducted through the microelectrode layer to the ASIC substrate and can be detected by a semiconductor measurement chip connected to the electrodes, thereby achieving the purpose of nucleic acid sequencing, protein sequencing, and other biomacromolecule detection.

[0066] The present disclosure provides a microelectrode for a biochip. Those skilled in the art will recognize that the biochip described herein can, more specifically, 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.

[0067] FIG2 is a schematic structural diagram of a microelectrode of a biochip according to an embodiment of the present disclosure. As shown in FIG2 , the microelectrode of a biochip according to an embodiment of the present disclosure may include: a substrate 210 , a current collector layer 230 , and an electrode layer 240 .

[0068] The substrate 210 may be an ASIC substrate as shown in FIG1 . The material of the substrate 210 may include silicon (Si), germanium (Ge), or a III-V semiconductor material. For example, the III-V semiconductor material may be gallium arsenide (GaAs).

[0069] The current collector layer 230 is formed on the substrate 210. The current collector layer 230 includes a first transition metal nitride thin film. The first transition metal here can include at least one of titanium (Ti), vanadium (V), tantalum (Ta), molybdenum (Mo), hafnium (Hf), and zirconium (Zr).

[0070] According to a preferred embodiment of the present disclosure, the thickness of the first transition metal nitride thin film of the current collector layer 230 is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm. Furthermore, in the first transition metal nitride thin film of the current collector layer 230, the stoichiometric ratio of the first transition metal element to nitrogen (N) is 0.9 to 1.1, and the oxygen (O) element, as an impurity, is present in an amount less than 15 mol%.

[0071] Those skilled in the art will appreciate that the current collector layer 230 described herein is formed on the substrate 210. In one case, the current collector layer 230 is directly formed on the substrate 210. Alternatively, other regions or layers may be formed on the substrate 210 first, and then the current collector layer 230 is formed. In other words, the term "A is above B" in this disclosure is not limited to the situation where A and B are directly and closely connected above and below each other, but only indicates the approximate upper and lower positional relationship between A and B.

[0072] According to a preferred embodiment of the present disclosure, the microelectrode of the biochip according to the present disclosure may optionally 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 formed directly on the substrate 210, and the current collector layer 230 is formed directly on the adhesion layer 220. The adhesion layer 220 includes a first transition metal thin film. As previously described, the first transition metal here may include at least one of Ti, V, Ta, Mo, Hf, and Zr.

[0073] According to a preferred embodiment of the present disclosure, the thickness of the first transition metal film of the adhesion layer 220 is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0074] Electrode layer 240 is formed on current collector layer 230. Electrode layer 240 comprises a thin film of a first transition metal oxynitride doped with a second metal. The second metal may also include at least one of Ti, V, Ta, Mo, Hf, and Zr. However, the second metal is different from the first transition metal.

[0075] According to a preferred embodiment of the present disclosure, the thickness of the second metal-doped first transition metal oxynitride film of electrode layer 240 is 10 to 5000 nm. Furthermore, the nitrogen content of the second metal-doped first transition metal oxynitride film of electrode layer 240 is 25 to 45 mol%, and the oxygen content is 15 to 35 mol%.

[0076] 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 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 the second metal.

[0077] 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 first transition metal nitride film, forming a compound interface.

[0078] 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 serves as the basic skeleton, and the second metal is solid-dissolved or dispersed in the basic skeleton as its nanoscale nitride oxide.

[0079] Accordingly, the present disclosure provides a method for preparing a microelectrode for a biochip. As described above, the biochip described herein can more specifically 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.

[0080] In general, the present disclosure proposes a supercapacitor material with 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 and gradually changing the composition and organizational structure of the film components, 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.

[0081] Figure 3 is a schematic flow chart of a method for preparing a microelectrode of a biochip according to an embodiment of the present disclosure. As shown in the flow chart of Figure 3 , the method for preparing a microelectrode of a biochip according to an embodiment of the present disclosure may start from step S310.

[0082] In step S310 , a substrate is provided.

[0083] 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.

[0084] The substrate may be made of one of Si, Ge, and Group III-V semiconductor materials, wherein the Group III-V semiconductor may be gallium arsenide or the like.

[0085] In step S320 , a first transition metal (M) nitride (MN) thin film is deposited on the substrate as a current collector layer.

[0086] As previously mentioned, an adhesion layer can be formed between the substrate and the current collector layer. Therefore, in a preferred embodiment of the present disclosure, step S320 can optionally further include: depositing a first transition metal (M) thin film on the substrate as the adhesion layer; and then depositing a first transition metal nitride (MN) thin film on the adhesion layer as the current collector layer.

[0087] 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.

[0088] 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).

[0089] Specifically, thin film deposition and co-deposition processes are used to effectively control mechanisms such as atomic diffusion and nucleation growth by adjusting process parameters: First, a smooth, dense, and highly conductive (low resistivity) first transition metal M thin film 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 adhesion layer as the current collector material. During deposition, process parameters such as the sputtering atmosphere are adjusted to gradually change the film composition from the transition metal M in the adhesion layer to the MN in the current collector layer, forming a compound interface. Then, based on the co-deposition process, by gradually adjusting deposition process parameters such as the sputtering working pressure, the film composition and structure are gradually transformed from the MN thin film to the MDNO thin film electrode layer with a rough surface, porous structure, and high specific capacitance, thereby achieving in-situ continuous growth of the MN current collector layer and the MDNO electrode layer. After the M / MN / MDNO composite structure electrode passes the physical and chemical performance tests (metallographic structure, electrochemical performance, and electrochemical stability), it is patterned using photolithography or a mask.

[0090] The thickness of the M film as the adhesion layer is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

[0091] 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.

[0092] The thickness of the MDNO film used as the electrode layer is 10 to 5000 nm.

[0093] The process parameters include target-substrate distance, the ratio of argon to nitrogen, M target material sputtering power, D target material sputtering power, substrate temperature, working gas pressure, substrate bias and other process parameters. Depending on different process machines, the parameters may be different, but they should not affect the essence and spirit of the invention disclosed and claimed in this disclosure.

[0094] The sputtering method is used to deposit the adhesion layer. The process parameters are as follows: target-substrate distance is 20-100 mm; sputtering power is 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.

[0095] The sputtering method is used, and the process parameters for depositing the collector layer are as follows: target-substrate distance is 20-100 mm; Ar:N2=(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.

[0096] The sputtering method is adopted, and the process parameters for depositing the electrode layer are specifically as follows: target-substrate distance is 20-100mm; Ar:N2=(10-200):(1-20)sccm; M target material sputtering power: 100-1000W; D target material sputtering power: 100-1000W; substrate temperature is room temperature to 400°C; working gas pressure is 0.4 to 2Pa; substrate bias is 0 to -400V; sputtering time: 5 to 500 minutes.

[0097] The M in the aforementioned MN (first transition metal nitride) is one or more transition metals such as Ti, Mo, V, Ta, Zr, and Hf. The stoichiometric ratio of M to N (M:N) in the nitride is between 0.9 and 1.1, and the oxygen impurity content is less than 15 mol%. The composition of the aforementioned MDNO (first transition metal oxynitride doped with a second metal) is affected by factors such as film preparation conditions, gases, target materials, and precursor purity. M and D are both transition metals such as Ti, Mo, V, Ta, Zr, and Hf, but D is different from M. The N content in the electrode material is between 25-45 mol%, and the O content is between 15-35 mol%.

[0098] Traditional thin film deposition processes include physical vapor deposition (PVD), including vacuum evaporation, sputtering coating, arc plasma deposition, etc.

[0099] In the preparation method disclosed herein, chemical vapor deposition (CVD) or atomic layer deposition (ALD) may also be used to deposit an adhesion layer / current collector layer / electrode layer on the cleaned substrate surface.

[0100] The composite supercapacitor structure of a transition metal adhesion layer / transition metal nitride current collector layer / metal-doped transition metal oxynitride electrode layer and its novel fabrication technology have great potential for high-throughput molecular detection chips. Compared to other manufacturing techniques, this technology offers advantages such as simplicity, low cost, a wide range of thin-film deposition technologies, and strong process applicability.

[0101] 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 the first transition metal doped with the second metal with a rough surface, porous structure, and high specific volume. The nitride oxide film, thereby realizing the in situ continuous growth of the first transition metal nitride film of the current collector layer and the nitride oxide film of the first transition metal doped with the second metal of the electrode layer.

[0102] Similarly, and 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.

[0103] In addition, as described above, during 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.

[0104] 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 represented by these expressions for nitrogen oxides are consistent. Moreover, "-N x O y There is no particular restriction on the values ​​of x and y, and theoretically they can be any integer values. 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).

[0105] The following is a comparison of the effects of a group of embodiments and comparative examples.

[0106] Example 1:

[0107] In this embodiment, a single crystal silicon substrate is selected as the substrate and the semiconductor industry standard RCA cleaning process is used to clean the substrate. DC reactive magnetron sputtering is used, and the target material is titanium (Ti) metal. The process parameters are: the background vacuum degree is 5×10 -4A Ti thin film with a thickness of 30 nm, a resistivity of 55.6 μΩ·cm, and a smooth surface was first deposited on the substrate surface as an adhesion layer under the following conditions: a target-substrate distance of 125 mm, a substrate temperature of 350°C, a working pressure of 0.4 Pa, an Ar gas flow rate of 30 sccm, and a deposition time of 5 minutes. Then, a TiN thin film with a thickness of 70.1 nm, a resistivity of 37.1 μΩ·cm, and a high density was deposited on the surface of the adhesion layer as a current collector layer by adjusting the deposition process parameters: a target-substrate distance of 125 mm, a working pressure of 0.4 Pa, an Ar:N2 ratio of 30:2.5 sccm, a substrate negative bias of -100 V, and a deposition time of 20 minutes. Furthermore, by adjusting the sputtering atmosphere and gradually introducing N2 gas, a gradual change in the composition at the interface between the adhesion layer and the current collector was achieved, i.e., a gradual transformation from Ti metal to TiN. The target materials used for co-deposition were titanium (Ti) and molybdenum (Mo), respectively. The co-deposition process parameters were gradually adjusted to: a titanium target-substrate distance of 125 mm, a molybdenum target-substrate distance of 115 mm, an Ar:N2 ratio of 20:8 sccm, a titanium target sputtering power of 200 W, a molybdenum target sputtering power of 150 W, a substrate temperature of 350°C, an operating pressure of 1.5 Pa, and a sputtering time of 20 minutes. This gradually altered the microstructure and composition of the TiN film, resulting in an in-situ growth of a 286 nm thick Ti-Mo-NO film with a resistivity of 11249 μΩ·cm and a rough surface with nanopores as the electrode layer. Cyclic voltammetry (CV) curves were measured using an electrochemical workstation using a three-electrode system with Ti-Mo-NO as the working electrode, platinum as the counter electrode, Ag / AgCl as the reference electrode, and KCl as the electrolyte, as shown in Figure 4. As can be seen from FIG4 , the curve has good rectangularity at high scan rate, indicating that the Ti adhesion layer, TiN current collector, and Ti-Mo-NO electrode prepared in this embodiment have low internal resistance and excellent rate characteristics.

[0108] Comparative Example 1:

[0109] In this comparative example, a single crystal silicon substrate was selected as the substrate and the semiconductor industry standard RCA cleaning process was used to clean the substrate. DC reactive magnetron sputtering was used, and the target material was titanium (Ti) metal. The process parameters were: the background vacuum was 5×10 -4Under the following conditions: 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 thin film with a thickness of 30 nm, a resistivity of 55.6 μΩ·cm, and a smooth surface was first deposited on the substrate surface as an adhesion layer. Then, under the following process parameters: target-substrate distance of 125 mm, Ar:N2=30:2.5 sccm, sputtering power of 200 W, substrate temperature of 350°C, working pressure of 0.4 Pa, substrate bias of -100 V, and sputtering time of 20 minutes, a TiN thin film with a thickness of 70.1 nm, a resistivity of 37.1 μΩ·cm, and a smooth surface with high density was first deposited on the substrate surface as a current collector layer. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance 125mm, Ar:N2=30:2.5sccm, sputtering power 200W, substrate temperature 350℃, working pressure 1.6Pa, sputtering time 20 minutes, a layer of TiN with a thickness of 265.5nm, a resistivity of 21327μΩ·cm, a rough surface and nano-micropores is grown in situ on the TiN film. x O y The film serves as the electrode layer.

[0110] Comparison between Example 1 and Comparative Example 1:

[0111] As shown in FIG5 , 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) increased by 1.5 to 1.8 times, and the specific capacitance still exceeded 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 standard measurement method is used to test its current response curve and measure its current decay time. The results are shown in Figure 6. As can be seen from Figure 6, 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 electrode prepared 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 operating time is increased from approximately 50ms to approximately 90ms, and the voltage driving capability is significantly improved.

[0112] Example 2:

[0113] In this embodiment, a single crystal silicon substrate is selected as the substrate and the semiconductor industry standard RCA cleaning process is used to clean the substrate. DC reactive magnetron sputtering is used, and the target material is vanadium (V) metal. The process parameters are: background vacuum is less than 10 -4 A 40nm thick, smooth V film with a resistivity of 65.5μΩ·cm was first deposited on the substrate surface as an adhesion layer under the following conditions: a target-substrate distance of 60mm, a substrate temperature of 450°C, a working pressure of 0.5Pa, Ar=50sccm, and a deposition time of 5 minutes. Then, by adjusting the deposition process parameters, a 65nm thick, smooth, high-density VN film with a resistivity of 416.5μΩ·cm was deposited on the adhesion layer surface as the current collector layer under the following conditions: a target-substrate distance of 60mm, a substrate temperature of 450°C, a working pressure of 0.5Pa, Ar:N2=50:10sccm, and a deposition time of 20 minutes. Furthermore, by adjusting the sputtering atmosphere and gradually introducing N2 gas, the composition at the interface between the adhesion layer and the current collector was gradually changed from V metal to VN. The target materials used for co-deposition were vanadium (V) and molybdenum (Mo), respectively. The co-deposition process parameters were gradually adjusted to: 60mm for the V target and 80mm for the Mo target, Ar:N2 = 20:4 sccm, 200W for the V target and 150W for the Mo target, substrate temperature of 450°C, working pressure of 1.5 Pa, and sputtering time of 20 minutes. This gradually altered the microstructure and composition of the VN film, resulting in an in-situ growth of a 300nm thick V-Mo-ON film with a resistivity of 10406 ​​μΩ·cm, a rough surface, and nanopores as the electrode layer. Cyclic voltammetry (CV) curves were measured using an electrochemical workstation using a three-electrode system with V-Mo-NO as the working electrode, platinum as the counter electrode, Ag / AgCl as the reference electrode, and KCl as the electrolyte, as shown in Figure 7. As can be seen from FIG7 , 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 low internal resistance and excellent rate characteristics.

[0114] Comparative Example 2:

[0115] In this comparative example, a single crystal silicon substrate was selected as the substrate and the semiconductor industry standard RCA cleaning process was used to clean the substrate. DC reactive magnetron sputtering was used, and the target material was molybdenum (Mo) metal. The process parameters were: background vacuum less than 10 -4A 40nm thick, smooth Mo film with a resistivity of 55.5μΩ·cm was first deposited on the substrate surface as an adhesion layer under the following conditions: target-substrate distance of 60mm, substrate temperature of 350°C, working pressure of 0.5Pa, Ar=50sccm, and deposition time of 5 minutes. Then, by adjusting the deposition process parameters, a 65nm thick, smooth, high-density MoN film with a resistivity of 178.5μΩ·cm was deposited on the adhesion layer as a current collector layer under the following conditions: target-substrate distance of 60mm, substrate temperature of 350°C, working pressure of 0.5Pa, Ar:N2=50:10sccm, and deposition time of 20 minutes. Then, by adjusting the deposition process parameters, the process parameters are: target substrate distance 80mm, Ar:N2=20:4sccm, sputtering power 150W, substrate temperature 350℃, working pressure 1.5Pa, sputtering time 20 minutes, a layer of MoN with a thickness of 300nm, a resistivity of 13250μΩ·cm, a rough surface and nano-micropores is grown in situ on the MoN film. x O y The film was used as the electrode layer. A three-electrode test system was used, with Mo-NO as the working electrode, Pt as the counter electrode, Ag\AgCl as the reference electrode, and KCl solution as the electrolyte. Cyclic voltammetry curves were measured using an electrochemical workstation, as shown in Figure 8.

[0116] Comparison of Example 2 and Comparative Example 2:

[0117] As shown in Figure 9, 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, as shown in Figure 10, the Mo adhesion layer\MoN current collector\MoN prepared in Comparative Example 2 x O y The electrode suffered severe corrosion after undergoing the electrochemical cyclic voltammetry test, and the film peeled off from the surface of the silicon substrate; however, the V adhesion layer\VN current collector\V-Mo-NO electrode prepared in Example 2 still maintained a smooth and intact surface state after undergoing the electrochemical cyclic voltammetry test, indicating that the addition of the V element greatly improved the corrosion resistance of the electrode.

[0118] The present disclosure also provides a biochip. The biochip may include the microelectrodes described in any of the preceding embodiments of the present disclosure. As previously mentioned, the biochip described herein may more specifically 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.

[0119] The implementation methods of the present disclosure are not limited to those described in the above 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 all considered to fall within the scope of protection of the present disclosure.

Claims

1. A microelectrode of a biochip, characterized in that, Comprising: A substrate; A current collector layer formed on the substrate, the current collector layer comprising a nitride film of a first transition metal; An electrode layer formed on the current collector layer, the electrode layer comprising a nitride oxide film of the first transition metal doped with a second metal.

2. The microelectrode of the biochip according to claim 1, wherein 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, wherein Further comprising: An adhesion layer formed between the substrate and the current collector layer, the adhesion layer comprising 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 metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr, and the second metal is different from the first transition metal.

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

8. The microelectrode of the biochip according to claim 4, wherein 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, wherein The thickness of the nitride oxide film of the first transition metal doped with the second metal is 10 - 5000 nm.

10. The microelectrode of the biochip according to claim 1, characterized in that, 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, oxygen element is an impurity with a content lower than 15 mol%.

11. The microelectrode of the biochip according to claim 1, characterized in that, In the nitride oxide 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%.

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

14. The microelectrode of the biochip according to claim 1, characterized in that, In the electrode layer, based on the lattice of the nitride oxide of the first transition metal as the basic framework, the second metal is solid-solved or its nano-scale nitride oxide is dispersed in the basic framework.

15. A method for preparing microelectrodes of a biochip, characterized in that, Comprising: Providing a substrate; Depositing a nitride film of a first transition metal on the substrate as the current collector layer; Co-depositing a nitride oxide film of the first transition metal doped with a second metal on the current collector layer as the electrode layer.

16. The method for preparing the microelectrode of the biochip according to claim 15, wherein The material of the substrate includes one of Si, Ge, and group III-V semiconductor materials.

17. The method for preparing the microelectrode of the biochip according to claim 16, characterized in that, The group III-V semiconductor material includes gallium arsenide.

18. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, The step of depositing a nitride film of a first transition metal on the substrate as the current collector layer further includes: Depositing a first transition metal film on the substrate as the adhesion layer; Depositing the nitride film of the first transition metal on the adhesion layer as the current collector layer.

19. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, The first transition metal includes at least one of Ti, V, Ta, Mo, Hf, and Zr.

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

21. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, The step of providing the substrate further includes: cleaning the surface of the substrate using a standard cleaning process.

22. The method for preparing the microelectrode of the biochip according to claim 15, wherein, The thickness of the nitride film of the first transition metal is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

23. The method for preparing the microelectrode of the biochip according to claim 18, characterized in that, The thickness of the first transition metal film is 10 to 5000 nm, and the resistivity is less than 500 μΩ·cm.

24. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, The thickness of the oxynitride film of the first transition metal doped with the second metal is 10 to 5000 nm.

25. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, 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 to 1.1, and among them, oxygen element is used as an impurity with a content lower than 15 mol%.

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

27. The method for preparing the microelectrode of the biochip according to claim 15, characterized in that, The step of co-depositing the oxynitride film of the first transition metal doped with the second metal as the electrode layer on the current collector layer includes: On the nitride film of the first transition metal of the current collector layer, based on the co-deposition process, by gradually adjusting the deposition process parameters, the tissue structure of the film changes gradually from a dense columnar crystal to a porous columnar crystal, and the component composition of the film gradually changes from the nitride film of the first transition metal to the oxynitride film of the first transition metal doped with the second metal with a rough surface, porous structure, and high specific capacitance, realizing the in-situ continuous growth of the nitride film of the first transition metal of the current collector layer and the oxynitride film of the first transition metal doped with the second metal of the electrode layer.

28. The method for preparing the microelectrode of the biochip according to claim 18, characterized in that, The step of depositing the nitride film of the first transition metal as the current collector layer on the adhesion layer includes: 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 gradually changes from the first transition metal film to the nitride film of the first transition metal, forming a compound interface.

29. The method for preparing the microelectrode of the biochip according to claim 15, wherein In the electrode layer, based on the crystal lattice of the oxynitride of the first transition metal, the second metal is solid-solved or its nano-scale oxynitride is dispersed in the basic framework.

30. A biochip, characterized in that, Including the microelectrode according to any one of claims 1-14.

31. The biochip according to claim 30, wherein, The biochip is a biomolecule detection chip.

32. The biochip according to claim 31, characterized in that, The biochip is a nucleic acid sequencing, protein sequencing chip, or enzyme screening chip.

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