Patent Application
20230010894
The present invention relates to the technical field of a gene sequencing chip, especially a microelectrode of a gene sequencing chip, a manufacturing method therefor, and a gene sequencing chip containing the microelectrode.
Supercapacitor materials are widely used in manufacturing a microelectrode in a biochip utilized in a gene sequencer, which have the characteristics of high power density, long cycle life, etc. A microelectrode is composed of two portions, i.e., an electrode and a current collector. The electrode charges and discharges through the energy storage mechanism to provide driving voltage for biochemical sequencing system. The collector transports electrons and is connected to a charge-discharge and measurement circuit, so as to provide charge-discharge current for the electrode and transmit a characteristic current signal of sequencing to a measurement chip.
At present, the commonly used microelectrodes in biochips utilized by a gene sequencer are mainly metal nitride electrodes deposited on a metal current collector made of Al, Au, Cu, etc. The research shows that these materials can exhibit a specific capacitance of more than 10 mF/cm2 when measured by the low scanning speed C-V method. However, due to the high internal resistance of the electrode material itself and the high contact resistance between the electrode and the current collector, the specific capacitance will rapidly decrease with the increase of the voltage sweep speed, and will be less than 4 mF/cm2 at a sweep speed greater than 0.1 V/s, thereby failing to ensure high specific capacitance and high charge-discharge rates at the same time. As a result, the voltage driving capacity per unit area is insufficient, and it is impossible to reduce the size of the microelectrode that meets the requirements to less than 5 microns, such that the number of sequencing units on a single chip exceeds ten million orders of magnitude.
The embodiments of the present application provide a microelectrode of a gene sequencing chip, a manufacturing method therefor, and a gene sequencing chip, for solving the problems in the prior art, i.e., insufficient voltage driving capacity per unit area of a microelectrode in a gene sequencing chip.
In the first aspect, an embodiment of the present application provides a microelectrode of a gene sequencing chip, comprising:
a substrate;
a current collector layer formed on the substrate, which comprises a transition metal thin film or a nitride thin film thereof or a composite thin film of a transition metal and nitride thereof;
an electrode layer formed on the current collector layer, which comprises an oxynitride thin film of the transition metal formed on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof.
In an optional embodiment, the material of the substrate comprises Si, Ge, one of the III-V semiconductor materials, or glass, or ceramics.
In an optional embodiment, the semiconductor materials comprise gallium arsenide.
In an optional embodiment, the transition metal comprises at least one of Ti, V, Ta, Mo and Hf
In an optional embodiment, the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof has a thickness of 10˜5,000 nm.
In an optional embodiment, the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof has a resistivity of less than 500 μΩ·cm.
In an optional embodiment, the oxynitride thin film of the transition metal has a thickness of 10˜5,000 nm,
In an optional embodiment, the oxynitride thin film of the transition metal has a resistivity of larger than 1,000 μΩ·cm.
In an optional embodiment, when the current collector layer comprises the nitride thin film of the transition metal or the composite thin film of the transition metal and the nitride thereof, the stoichiometric ratio of metal element to nitrogen element in the nitride is 0.9˜1.1.
In an optional embodiment, in the oxynitride thin film of the transition metal, the nitrogen content is 15˜49 mol %, and the oxygen content is 1˜35 mol %.
In the second aspect, an embodiment of the present application provides a manufacturing method for a microelectrode of a gene sequencing chip, comprising:
providing a substrate;
depositing a transition metal thin film or a nitride thin film thereof or a composite thin film of a transition metal and nitride thereof on the substrate as a current collector layer;
depositing an oxynitride thin film of the transition metal on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof as an electrode layer.
In an optional embodiment, cleaning the surface of the substrate using a standard cleaning process is further included.
In an optional embodiment, depositing an oxynitride thin film of the transition metal on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof as an electrode layer comprises: continuously growing in situ, a layer of oxynitride thin film of the transition metal with rough surface, nanopores and high specific capacitance, on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof, as an electrode layer, by adjusting deposition process parameters.
In an optional embodiment, the material of the substrate comprises Si, Ge, one of III-V semiconductor materials, or glass, or ceramics.
In an optional embodiment, the III-V semiconductor materials comprise gallium arsenide.
In an optional embodiment, the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof has a thickness of 10˜5,000 nm.
In an optional embodiment, the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof has a resistivity of less than 500 μΩ·cm.
In an optional embodiment, the oxynitride thin film of the transition metal has a. thickness of 10˜5,000 μΩ·cm.
In an optional embodiment, the oxynitride thin film of the transition metal has a resistivity of larger than 1,000 μΩ·cm.
In an optional embodiment, when the current collector layer comprises the nitride thin film of the transition metal or the composite thin film of the transition metal and the nitride thereof, the stoichiometric ratio of metal element to nitrogen element in the nitride is 0.9˜1.1.
In an optional embodiment, in the oxynitride thin film of the transition metal, the nitrogen content is 15˜49 mol %, and the oxygen content is 1˜35 mol %.
In the third aspect, the present application provides a gene sequencing chip, which comprises the microelectrode described in any embodiments as mentioned above.
In comparison with the prior art, through tailoring of material properties by changing deposition process parameters of thin films, the embodiments of the present application are able to achieve continuously growing in situ, a current collector layer, i.e., a transition metal thin film or a nitride thin film thereof or a composite thin film of a. transition metal and nitride thereof with high conductivity, and an electrode layer, i.e., an oxynitride thin film of the transition metal with high specific capacitance. Therefore, the manufactured microelectrode can be provided with high specific capacitance and high charge-discharge rates at the same time, and the voltage driving capacity per unit area is improved. Further, the electrode material, i.e., oxynitride of a transition metal, can maintain high structural stability and electrochemical stability in the biochemical environment of sequencing, meet the requirements for an ultra-high number of cycles, and improve the throughput and stability of a gene sequencing chip. Moreover, the materials for manufacturing the microelectrode are common commercial materials with simple process, low cost, strong producibility and easy to achieve mass production.
The present invention will be more fully understood by the following detailed description in conjunction with the accompanying drawings, in which similar elements are numbered in a similar manner, wherein:
The technical solutions of the present application will be clearly and completely described below through the embodiments and in conjunction with the accompanying drawings. However, the present application is not limited to the embodiments described below. Based on the following embodiments, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application. For the sake of clarity, parts unrelated to describing the exemplary embodiments are omitted from the drawings.
It should be understood that terms such as “comprising” or “having” in this application are intended to indicate the presence of features, numbers, steps, acts, components or combinations thereof disclosed in this specification, and do not exclude the possibility that one or more other features, numbers, steps, behaviors, components or combinations thereof exist or are added.
As mentioned above, the microelectrode in a gene sequencing chip in the prior art is usually a metal nitride electrode deposited on a metal current collector made of Al, Au, and Cu, etc. The voltage driving capacity per unit area of this microelectrode material is insufficient and cannot meet the manufacturing requirement that the number of sequencing units in a single chip exceeds ten million orders of magnitude. With the study of the application of nitride (such as Tin, etc.), oxide (such as RuO2, MnO2, etc.) and oxynitride (such as TiNxOy, VNxOy, etc.) thin films of transition metals in the electrode materials of supercapacitors, the specific capacitance and resistivity can be controlled in a large range by adjusting the deposition process parameters and by adjusting the stoichiometric ratio of chemical components, crystallographic orientation, micro morphology, etc. In the microelectronics industry, TiN and TaN thin films with high conductivity are also used in the manufacturing of gate electrodes of transistors. Therefore, based on the controllable specific capacitance and resistivity of the oxynitride of the transition metal in a large range and the excellent conductivity of the transition metal or the nitride thereof, the present application proposes a new microelectrode for a gene sequencing chip and the manufacturing method therefor, which solve the problem of insufficient voltage driving capacity per unit area of traditional electrode materials in a gene sequencing chip, and significantly improve the throughput and stability of the gene sequencing chip.
The current collector layer 102 is formed by depositing a transition metal (M) thin film or a nitride (MN) thin film thereof or a composite (a composite of M and Mn) thin film of a transition metal and nitride thereof on the surface of the substrate 101. The electrode layer 103 is formed by depositing an oxynitride (MNxOy) thin film of the transition metal on the current collector layer 102.
By depositing an oxynitride thin film of the transition metal as an electrode layer on the highly conductive current collector layer of the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof, high specific capacitance and high charge-discharge rates of a microelectrode are realized in the embodiments of the present application. The structure of this microelectrode can maintain high structural stability and electrochemical stability in the biochemical environment of sequencing, and can improve the throughput and stability of the gene sequencing chip.
In some embodiments, the material of the substrate 101 may include the semiconductor material, such as silicon (Si) or germanium ((Ge), or one of III-V semiconductor materials, such as gallium arsenide, and may also include the material for semiconductor manufacturing industries, such as glass substrates, ceramics, etc.
In some embodiments, the transition metal (M) may include at least one of titanium (Ti), vanadium (V), tantalum (Ta), molybdenum (Mo) and hafnium (Hf).
In some embodiments, the transition metal (M) thin film or the nitride (MN) thin film thereof or the composite thin film of the transition metal and the nitride thereof has a smooth surface, high density, low resistivity and high conductivity. As an example, the transition metal (M) thin film or the nitride (MN) thin film thereof or the composite thin film of the transition metal and the nitride thereof has a thickness of 10˜5000 nm, and a resistivity of less than 500 μΩ·cm.
In some embodiments, the oxynitride thin film of the transition metal has a rough surface, exhibits a porous structure with nanopores, and has high resistivity, low conductivity and high specific capacitance. As an example, the oxynitride (MNxOy) thin film of the transition metal has a thickness of 10˜5,000 nm, and a resistivity of larger than 1,000 μΩ·cm.
in some embodiments, when the current collector layer 102 is formed with the nitride (MN) thin film of the transition metal or the composite (a composite of M and Mn) thin film of the transition metal and the nitride thereof, the stoichiometric ratio of metal element (M) to nitrogen element (N) in the nitride is 0.91.1, and the oxygen content is less than 15 mol %. The nitride thin film of the transition metal with a stoichiometric ratio close to 1:1 has excellent electrical conductivity.
In some embodiments, the composition of the oxynitride thin film of the transition metal is affected by factors such as film manufacturing conditions, the purity of the gas, the target and the precursor, and wherein the nitrogen content is 15˜49 mol % and the oxygen content is 1˜35 mol %.
Step S210, providing a substrate.
In this step, the substrate can be cleaned using a standard cleaning process first to remove impurities and dirt on the surface of the chip substrate. In some embodiments, the material of the substrate may include the semiconductor material such as silicon (Si) or germanium (Ge), or one of the III-V semiconductor materials, such as gallium arsenide, and may also include glass substrates. The substrate may have undergone other processes, such as forming patterns, structures, electrodes, etc., which are required for integrated circuits.
Step S220, depositing a transition metal thin film or a nitride thin film thereof or a composite thin film of a transition metal and nitride thereof on the substrate as a current collector layer.
In this step, the film deposition process may be utilized, effective regulation of the mechanism such as atomic diffusion and nucleation growth can be achieved by adjusting process parameters, and a layer of a transition metal (M) thin film or a nitride (MN) thin film thereof or a composite (a composite of M and Mn) thin film of a transition metal and nitride thereof, with smooth surface, high density and high conductivity (low resistivity), is deposited on the cleaned substrate as a current collector layer.
In some embodiments, the transition metal (M) may include at least one of titanium (Ti), vanadium (V), tantalum (Ta), molybdenum (Mo), and hafnium (Hf).
The process parameters include target-substrate distance, the ratio of argon to nitrogen, sputtering power, substrate temperature, working pressure, substrate bias voltage and other process parameters. It should be noted that the parameters may be different according to different process machines, and the differences of such process parameters do not affect the essence of the invention claimed in the present application, and are also covered by the protection scope of the embodiments of the present application.
In some embodiments, the film deposition process may include physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALIS). Among them, the physical vapor deposition may include vacuum evaporation, sputtering coating, and arc plasma coating.
In some embodiments, when depositing the current collector layer by sputtering coating, a set of exemplary process parameters may be: target-substrate distance: 20˜100 mm; Ar:N2=(10-200):(1-20) sccm; sputtering power: 100˜10000 W; substrate temperature: room temperature to 400° C.; working pressure: 0.2˜2 Pa; substrate bias voltage: −50˜−400 V; and sputtering time: 0.5˜500 min. In some embodiments, the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof has a thickness of 10˜5,000 nm, and a resistivity of less than 500 μΩ·cm.
In some embodiments, when the current collector layer is formed with the nitride (MN) thin film of the transition metal or the composite (a composite of M and MN) thin film of the transition metal and the nitride thereof, the stoichiometric ratio of metal element (M) to nitrogen element (N) in the nitride is 0.9˜1.1, and the oxygen content is less than 15 mol %. The nitride thin film of the transition metal with a. stoichiometric ratio close to 1:1 has excellent electrical conductivity.
Step S230, depositing an oxynitride thin film of the transition metal on the transition metal thin film or the nitride thin film thereof or the composite thin film of the transition metal and the nitride thereof as an electrode layer.
In this step, by adjusting deposition process parameters and changing growth conditions for the film to achieve certain crystallographic orientation and micro morphology, a layer of an oxynitride (MNxOy) thin film of the transition metal, with rough surface, porous structure, low conductivity (high resistivity) and high specific capacitance, is continuously grown in situ on the current collector layer of the transition metal (M) thin film or the nitride (MN) thin film thereof or the composite (M and MN composite) thin film of the transition metal and the nitride thereof, as an electrode layer. The electrode layer of the oxynitride (MNxOy) of the transition metal can be patterned by means of photolithography or mask after passing the physical and chemical property test.
In some embodiments, when depositing the electrode layer by sputtering coating, a set of exemplary process parameters may be: target-substrate distance: 20˜100 mm; Ar:N2=(10-200):(1-20) sccm; sputtering power: 100˜10000 W; substrate temperature: room temperature to 400° C.; working air pressure: 0.4˜2 Pa; and sputtering time: 0.5˜500 min.
In some embodiments, the oxynitride thin film of the transition metal has a thickness of 10˜5000 nm, and a resistivity of larger than 1000 μΩ·cm.
in some embodiments, the composition of the oxynitride thin film of the transition metal is affected by factors such as film manufacturing conditions, the purity of gas, the target and the precursor, and wherein the nitrogen content is 15˜49 mol % and the oxygen content is 1˜35 mol %.
The following is a comparative description based on the TiNxOy single electrode and the VNxOy single electrode respectively manufactured according to Comparative Embodiment 1 and Comparative Embodiment 2, and the microelectrodes respectively manufactured according to Embodiment 1 and Embodiment 2 of the present application.
In this comparative embodiment, a monocrystalline silicon wafer is utilized as a substrate, and the substrate is cleaned by the standard RCA cleaning process in the semiconductor industry. A layer of titanium oxynitride (TiNxOy) single electrode, with a thickness of 200 nm, a porous structure and a resistivity of 2,00 μΩ·cm, is grown on the surface of the substrate, by adopting DC reactive magnetron sputtering, wherein the target material is titanium, and the process parameters are: target-substrate distance: 30 mm, Ar:N2=10:1.1 sccm, sputtering power: 150 W, substrate temperature: 200° C., working pressure: 0.5 Pa, and puttering time: 20 min. By using the three-electrode test system, wherein the working electrode is TiNxOy, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is KCl solution, a cyclic voltammetry curve is tested by the electrochemical workstation, as shown in
Comparative Embodiment 2:
In this comparative embodiment, a monocrystalline silicon wafer is utilized as a substrate, and the substrate is cleaned by the standard RCA cleaning process in the semiconductor industry. A layer of porous VNxOy electrode with a thickness of 220 nm and a resistivity of 3,200 μΩ·cm is grown on the surface of the substrate, by adopting DC reactive magnetron sputtering, and wherein the target material is vanadium, and the process parameters are: target-substrate distance: 50 mm, AR:N2−15:1.5 sccm, sputtering power: 250 W, substrate temperature: 300° C., working pressure: 0.6 Pa, and sputtering time: 20 min. By using the three-electrode test system, wherein the working electrode is VNxOy, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is KCl solution, a cyclic voltammetry curve is tested by the electrochemical workstation, as shown in
In this embodiment, a monocrystalline silicon wafer is utilized as a substrate, and the substrate is cleaned by the standard RCA cleaning process in the semiconductor industry. A layer of TiN thin film, with a thickness of 58 nm, a resistivity of 88 μΩ·cm, a smooth surface and high density, is deposited on the surface of the substrate as the current collector layer, by adopting DC reactive magnetron sputtering, wherein the target material is titanium, and the process parameters are: target-substrate distance: 30 mm, Ar:N2=10:1.1 sccm, sputtering power: 130 W, substrate temperature: 100° C., working pressure: 0.3 Pa, substrate bias voltage: −50 V, and the sputtering time: 15 min. Then, by adjusting the deposition process parameters, a TiNxOy film with a thickness of 200 nm, a resistivity of 2000 μΩ·cm, a rough surface and nanopores is grown in situ on the TiN film as an electrode layer, wherein the process parameters are: target-substrate distance: 30 mm, Ar:N2=10:1.1 sccm, sputtering power: 150 W, substrate temperature: 200° C., working pressure: 0.5 Pa, and sputtering time: 20 min. By using the three-electrode test system, wherein the working electrode is TiNxOy, the counter electrode is a platinum electrode, the reference electrode is Ag\AgCl, and the electrolyte is KCl solution, a cyclic voltammetry curve is tested by the electrochemical workstation, as shown in
In this embodiment, a monocrystalline silicon wafer is utilized as a substrate, and the substrate is cleaned by the standard RCA cleaning process in the semiconductor industry. A layer of VN film, with a smooth surface, high density and high conductivity (low resistivity), is deposited on the surface of the cleaned substrate as the current collector layer, by adopting RF reactive magnetron sputtering, wherein the target material is vanadium, and the process parameters are: target-substrate distance: 20˜100 mm, ArN2=(10-60):(1-10)sccm, sputtering power: 100˜400 W, substrate temperature: room temperature to 400° C., working pressure: 0.2˜2 Pa, substrate bias voltage: −50˜−400 V, and sputtering time: 5˜500 min, Then, by adjusting the deposition process parameters, a VNxOy film with a rough surface, nanopores and low conductivity (high resistivity) is grown in situ on the VN film as an electrode layer, wherein the process parameters are: target-substrate distance: 20˜100 mm, Ar:N2. (10-60):(1-10) sccm, sputtering power: 100˜400 W, substrate temperature: room temperature to 400° C., working pressure: 0.4˜2 Pa, and sputtering time: 5˜500 min. By using the three-electrode test system, a cyclic voltammetry curve is tested by the electrochemical workstation, as shown in
An embodiment of the present application also provides a gene sequencing chip, which includes the microelectrode mentioned in any embodiment of the present application as described above.
The electrode of a gene sequencing chip and the manufacturing method therefor according to the embodiments of the present application overcome the defects of the traditional microelectrodes, i.e., being unable to be provided with high specific capacitance and high charge-discharge rates at the same time, which results in insufficient voltage driving capacity per unit area. In addition, the electrode material, i.e., the oxynitride of a transition metal, can maintain high structural stability and electrochemical stability in the biochemical environment of sequencing, meet the requirements for an ultra-high number of cycles, and improve the throughput and stability of the gene sequencing chip. Moreover, the materials for manufacturing the microelectrode are common commercial materials with simple process, low cost, strong producibility and easy to achieve mass production.
The embodiments of the present application are not limited to the those described in the above-mentioned embodiments. Without departing from the spirit and scope of the present application, those skilled in the art can make various changes and improvements to the present application in form and detail, all of which are considered to fall within the protection scope of the present application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201911283304.2 | Dec 2019 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2020/135772 | 12/11/2020 | WO |
