Biosensor and method for preparing the same

Abstract

The present invention relates to a biosensor and a preparation method thereof. The biosensor comprises: a target substrate; a patterned functional layer located on the upper surface of the target substrate, the patterned functional layer comprising a patterned boron nitride layer and a patterned graphene layer, the patterned boron nitride layer being located on the upper surface of the target substrate, and the patterned graphene layer being located on the upper surface of the patterned boron nitride layer. The present invention can avoid a decrease in the detection sensitivity of the biosensor.

Description

Technical Field

[0001] The present application relates to the field of biological detection technology, and in particular to a biosensor and a preparation method thereof. Background Art

[0002] With the development of biological detection technology, biosensor technology has emerged. Biosensors are instruments that are sensitive to biological substances and convert their concentrations into electrical signals for detection. They are usually composed of immobilized biological sensitive materials as recognition elements (such as antibodies, etc.), appropriate physical and chemical transducers (such as field effect transistors, etc.) and signal amplification devices. Biosensors have the advantages of high accuracy, fast analysis speed, low cost, and simple operation, and their application scenarios are very broad.

[0003] In the traditional method of preparing biosensors, a layer of graphene is usually grown on a copper foil, then the copper foil is removed and the graphene is transferred to a target substrate, and then the graphene on the target substrate is patterned and functionalized to finally produce a biosensor. However, in traditional technology, because graphene is relatively fragile, it is easy to wrinkle or even break during the transfer process to the target substrate, resulting in a decrease in the detection sensitivity of the prepared biosensor. Summary of the invention

[0004] Based on this, it is necessary to provide a biosensor and a preparation method thereof to address the problem of decreased detection sensitivity of biosensors in the prior art.

[0005] In order to achieve the above object, the present invention provides a biosensor. The biosensor comprises:

[0006] target substrate;

[0007] A patterned functional layer is located on the upper surface of the target substrate, and the patterned functional layer includes a patterned boron nitride layer and a patterned graphene layer. The patterned boron nitride layer is located on the upper surface of the target substrate, and the patterned graphene layer is located on the upper surface of the patterned boron nitride layer.

[0008] In one embodiment, the biosensor further comprises:

[0009] A first electrode is located on the upper surface of the patterned graphene layer and on one side of the patterned graphene layer;

[0010] The second electrode is located on the upper surface of the patterned graphene layer and on a side of the patterned graphene layer away from the first electrode.

[0011] In one embodiment, the target substrate includes a silicon wafer, a silicon carbide substrate or a gallium nitride substrate.

[0012] The biosensor of the present invention comprises: a target substrate; and a patterned functional layer located on the upper surface of the target substrate. Since the patterned functional layer is a double-layer structure including a patterned boron nitride layer and a patterned graphene layer, and the patterned boron nitride layer is located on the upper surface of the target substrate, and the patterned graphene layer is located on the upper surface of the patterned boron nitride layer, the strength is higher than that of a single graphene layer. Therefore, in the process of transferring the functional layer to the target substrate, wrinkles or damages of the graphene layer can be avoided, thereby avoiding a decrease in the detection sensitivity of the biosensor.

[0013] The present invention also provides a method for preparing a biosensor, the method for preparing the biosensor comprising:

[0014] providing a metal growth substrate;

[0015] Forming a functional layer on the upper surface of the metal growth substrate, the functional layer comprising a boron nitride layer and a graphene layer, the boron nitride layer being located on the upper surface of the metal growth substrate, and the graphene layer being located on the upper surface of the boron nitride layer;

[0016] removing the metal growth substrate, transferring the functional layer to the upper surface of the target substrate, and then patterning the functional layer to obtain a patterned functional layer, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer; or

[0017] The functional layer is patterned to obtain a patterned functional layer; the metal growth substrate is removed, and the patterned functional layer is transferred to the upper surface of the target substrate, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer.

[0018] In one embodiment, removing the metal growth substrate, transferring the functional layer to the upper surface of the target substrate and then patterning the functional layer to obtain a patterned functional layer includes:

[0019] removing the metal growth substrate;

[0020] providing a target substrate;

[0021] transferring the functional layer to the upper surface of the target substrate;

[0022] The functional layer is patterned to obtain the patterned functional layer.

[0023] In one embodiment,

[0024] After forming a functional layer on the upper surface of the metal growth substrate and before removing the metal growth substrate, the method further includes:

[0025] forming a first supporting protective layer on the upper surface of the graphene layer;

[0026] forming a second supporting and protecting layer on the upper surface of the first supporting and protecting layer;

[0027] After transferring the functional layer to the upper surface of the target substrate and before patterning the functional layer, the method further includes:

[0028] The second supporting protective layer and the first supporting protective layer are removed.

[0029] In one embodiment, patterning the functional layer to obtain a patterned functional layer; removing the metal growth substrate, and transferring the patterned functional layer to the upper surface of the target substrate includes:

[0030] forming a photoresist layer on the upper surface of the graphene layer;

[0031] Patterning the photoresist layer to obtain a patterned photoresist layer;

[0032] Etching the functional layer based on the patterned photoresist layer to obtain the patterned functional layer;

[0033] removing the metal growth substrate;

[0034] The patterned functional layer is transferred to the upper surface of the target substrate.

[0035] In one embodiment, after etching the functional layer based on the patterned photoresist layer and before removing the metal growth substrate, the method further includes:

[0036] forming a supporting protective layer on the upper surface of the patterned photoresist layer;

[0037] After transferring the patterned functional layer to the upper surface of the target substrate, the method further comprises:

[0038] The supporting protection layer and the patterned photoresist layer are removed.

[0039] In one embodiment, the metal growth substrate comprises copper foil.

[0040] In one embodiment, after the functional layer is patterned to obtain a patterned functional layer, the method further includes:

[0041] A first electrode and a second electrode are formed on the upper surface of the patterned graphene layer, wherein the first electrode is located on one side of the patterned graphene layer, and the second electrode is located on a side of the patterned graphene layer away from the first electrode.

[0042] The method for preparing the biosensor of the present invention forms a functional layer on the upper surface of the metal growth substrate, wherein the functional layer includes a boron nitride layer and a graphene layer, wherein the boron nitride layer is located on the upper surface of the metal growth substrate, and the graphene layer is located on the upper surface of the boron nitride layer. Since the functional layer is a double-layer structure of a boron nitride layer and a graphene layer, the strength is higher than that of a single graphene layer, and therefore wrinkles or damages of the graphene layer can be avoided during the process of transferring the functional layer to the target substrate, thereby avoiding a decrease in the detection sensitivity of the biosensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 is a flow chart of a method for preparing a biosensor provided in an embodiment;

[0045] Figure 2 It is a schematic diagram of the cross-sectional structure of the structure obtained in step S101 in the method for preparing a biosensor provided in an embodiment;

[0046] Figure 3 is a schematic diagram of a cross-sectional structure of a structure obtained in step S102 in a method for preparing a biosensor provided in an embodiment;

[0047] Figure 4 is a schematic diagram of a cross-sectional structure of a structure obtained in step S103 in a method for preparing a biosensor provided in an embodiment;

[0048] Figure 5 A schematic diagram of a process for removing a metal growth substrate, transferring a functional layer to an upper surface of a target substrate, and then patterning the functional layer to obtain a patterned functional layer in a method for preparing a biosensor provided in an embodiment;

[0049] Figure 6 is a schematic cross-sectional view of a structure obtained in step S501 in a method for preparing a biosensor provided in an embodiment;

[0050] Figure 7 is a schematic cross-sectional view of a structure obtained in step S502 in a method for preparing a biosensor provided in an embodiment;

[0051] Figure 8is a schematic cross-sectional view of a structure obtained in step S503 in a method for preparing a biosensor provided in an embodiment;

[0052] Fig. 9 is a schematic cross-sectional view of a structure obtained in step S504 in a method for preparing a biosensor provided in an embodiment;

[0053] Fig.10 It is a schematic flow diagram of the structure after forming a functional layer on the upper surface of a metal growth substrate and before removing the metal growth substrate in a method for preparing a biosensor provided in an embodiment;

[0054] Fig.11 is a schematic cross-sectional view of a structure obtained in step S1001 in a method for preparing a biosensor provided in an embodiment;

[0055] Fig.12 is a schematic cross-sectional view of a structure obtained in step S1002 in a method for preparing a biosensor provided in an embodiment;

[0056] Fig.13 A schematic diagram of the process of patterning a functional layer to obtain a patterned functional layer in a method for preparing a biosensor provided in an embodiment; removing a metal growth substrate; and transferring the patterned functional layer to an upper surface of a target substrate;

[0057] Fig.14 is a schematic cross-sectional view of a structure obtained in step S1301 in a method for preparing a biosensor provided in an embodiment;

[0058] Fig.15 is a schematic cross-sectional view of a structure obtained in step S1302 in a method for preparing a biosensor provided in an embodiment;

[0059] Fig.16 is a schematic cross-sectional view of a structure obtained in step S1303 in a method for preparing a biosensor provided in an embodiment;

[0060] Fig.17 is a schematic cross-sectional view of a structure obtained in step S1304 in a method for preparing a biosensor provided in an embodiment;

[0061] Fig.18 is a schematic cross-sectional view of a structure obtained in step S1305 in a method for preparing a biosensor provided in an embodiment;

[0062] Fig.19 A cross-sectional schematic diagram of forming a supporting protective layer structure on the upper surface of a patterned photoresist layer in a method for preparing a biosensor provided in an embodiment;

[0063] Fig. 20The figure is a schematic diagram of a process of forming a first electrode and a second electrode structure on an upper surface of a patterned graphene layer in a method for preparing a biosensor provided in an embodiment.

[0064] Description of reference numerals:

[0065] 10-metal growth substrate, 20-functional layer, 201-boron nitride layer, 202-graphene layer, 30-target substrate, 40-patterned functional layer, 401-patterned boron nitride layer, 402-patterned graphene layer, 50-first supporting protective layer, 60-second supporting protective layer, 601-first electrode, 602-second electrode, 70-photoresist layer, 701-patterned photoresist layer, 80-supporting protective layer. DETAILED DESCRIPTION

[0066] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0068] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. On the contrary, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and / or parts, these elements, components, regions, layers, doping types and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type or part from another element, component, region, layer, doping type or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, doping type or portion discussed below may be represented as a second element, component, region, layer or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0069] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0070] When used herein, the singular forms "a", "an" and " / the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0071] Embodiments of the invention are described herein with reference to cross-sectional views which are schematic diagrams of ideal embodiments (and intermediate structures) of the invention, such that variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances are anticipated. Thus, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include deviations in shapes due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the invention.

[0072] With the development of biological detection technology, biosensor technology has emerged. Biosensors are instruments that are sensitive to biological substances and convert their concentrations into electrical signals for detection. They are usually composed of immobilized biological sensitive materials as recognition elements (such as antibodies, etc.), appropriate physical and chemical transducers (such as field effect transistors, etc.) and signal amplification devices. Biosensors have the advantages of high accuracy, fast analysis speed, low cost, and simple operation, and their application scenarios are very broad.

[0073] In the traditional method of preparing biosensors, a layer of graphene is usually grown on a copper foil, then the copper foil is removed and the graphene is transferred to a target substrate, and then the graphene on the target substrate is patterned and functionalized to finally produce a biosensor. However, in traditional technology, because graphene is relatively fragile, it is easy to wrinkle or even break during the transfer process to the target substrate, resulting in a decrease in the detection sensitivity of the prepared biosensor.

[0074] Based on this, it is necessary to provide a biosensor and a preparation method thereof to address the above problems.

[0075] See also Figure 1 The present invention provides a method for preparing a biosensor, comprising the following steps:

[0076] S101: providing a metal growth substrate;

[0077] S102: forming a functional layer on the upper surface of the metal growth substrate, the functional layer comprising a boron nitride layer and a graphene layer, the boron nitride layer being located on the upper surface of the metal growth substrate, and the graphene layer being located on the upper surface of the boron nitride layer;

[0078] S103: removing the metal growth substrate, transferring the functional layer to the upper surface of the target substrate, and then patterning the functional layer to obtain a patterned functional layer, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer; or

[0079] The functional layer is patterned to obtain a patterned functional layer; the metal growth substrate is removed, and the patterned functional layer is transferred to the upper surface of the target substrate, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer.

[0080] The preparation method of the biosensor of the present invention forms a functional layer on the upper surface of a metal growth substrate, wherein the functional layer includes a boron nitride layer and a graphene layer, wherein the boron nitride layer is located on the upper surface of the metal growth substrate, and the graphene layer is located on the upper surface of the boron nitride layer. Since the functional layer is a double-layer structure of a boron nitride layer and a graphene layer, the strength is higher than that of a single graphene layer, and therefore wrinkles or damages of the graphene layer can be avoided during the process of transferring the functional layer to the target substrate, thereby avoiding a decrease in the detection sensitivity of the biosensor.

[0081] In step S101, refer to Figure 1 Step S101 and Figure 2 , providing a metal growth substrate 10.

[0082] In some examples, metal growth substrate 10 may include copper foil.

[0083] In step S102, refer to Figure 1 Step S102 and Figure 3 A functional layer 20 is formed on the upper surface of the metal growth substrate 10 , and the functional layer 20 includes a boron nitride layer 201 and a graphene layer 202 . The boron nitride layer 201 is located on the upper surface of the metal growth substrate 10 , and the graphene layer 202 is located on the upper surface of the boron nitride layer 201 .

[0084] In some examples, before forming the functional layer 20 on the upper surface of the metal growth substrate 10 , the metal growth substrate 10 may be cleaned.

[0085] Optionally, taking the metal growth substrate 10 as a copper foil as an example, the copper foil may be placed in nitric acid for cleaning for 10-20 seconds until the copper foil slightly bubbles and then taken out to complete the cleaning.

[0086] In some examples, the step of forming the functional layer 20 on the upper surface of the metal growth substrate 10 can be performed by a chemical vapor deposition (CVD) process.

[0087] Optionally, taking the metal growth substrate 10 as a copper foil as an example, the cleaned copper foil can be placed in a CVD tube furnace, and argon and hydrogen are continuously introduced, wherein the ratio of argon to hydrogen is 19:1, and the total amount is 500 sccm. Then, the borane ammonia gas path is opened to introduce borane ammonia, wherein the time for introducing borane ammonia is 30 minutes, and the total amount is 30 sccm, so as to grow a layer of boron nitride layer 201 on the upper surface of the copper foil. Thereafter, the copper foil may not be taken out of the CVD tube furnace, at which time the borane ammonia gas path is closed to stop introducing borane ammonia, and the methane gas path is opened to introduce methane, wherein the time for introducing methane is 30 minutes, and the total amount is 30 sccm, so that a graphene layer 202 can be grown on the boron nitride layer 201. Finally, the methane gas path is closed, the CVD tube furnace stops heating, and the tube furnace is opened after the tube furnace cools to room temperature, so as to form a functional layer 20 on the upper surface of the copper foil.

[0088] In step S103, refer to Figure 1 Step S103 and Figure 4 , removing the metal growth substrate 10, transferring the functional layer 20 to the upper surface of the target substrate 30, and then patterning the functional layer 20 to obtain a patterned functional layer 40, wherein the patterned functional layer 40 includes a patterned graphene layer 402 and a patterned boron nitride layer 401; or

[0089] The functional layer 20 is patterned to obtain a patterned functional layer 40 ; the metal growth substrate 10 is removed, and the patterned functional layer 40 is transferred to the upper surface of the target substrate 30 , wherein the patterned functional layer 40 includes a patterned graphene layer 402 and a patterned boron nitride layer 401 .

[0090] In some examples, the target substrate 30 may include a silicon wafer, a silicon carbide substrate, or a gallium nitride substrate.

[0091] In one embodiment, Figure 5 As shown, removing the metal growth substrate, transferring the functional layer to the upper surface of the target substrate and then patterning the functional layer to obtain a patterned functional layer may include the following steps:

[0092] S501: removing the metal growth substrate;

[0093] S502: providing a target substrate;

[0094] S503: transferring the functional layer to the upper surface of the target substrate;

[0095] S504: Graphically process the functional layer to obtain a graphic functional layer.

[0096] In step S501, refer to Figure 5 Step S501 and Figure 6, removing the metal growth substrate 10.

[0097] In some examples, before removing the metal growth substrate 10, a step of removing the functional layer 20 on the lower surface of the metal growth substrate 10 may also be included. It is understood that if the above-mentioned step of forming the functional layer 20 on the upper surface of the metal growth substrate 10 is prepared by a CVD process, since the CVD process will also form a redundant functional layer 20 on the lower surface of the metal growth substrate 10, before removing the metal growth substrate 10, the redundant functional layer 20 on the lower surface of the metal growth substrate 10 needs to be removed, so as to prevent the redundant graphene layer 202 from stacking during the transfer process.

[0098] Optionally, a plasma etching process may be used to remove the redundant functional layer 20 on the lower surface of the metal growth substrate 10 .

[0099] In some examples, metal growth substrate 10 may be removed using chemical agents.

[0100] Optionally, taking the metal growth substrate 10 as copper foil as an example, the copper foil can be corroded using a 0.1 mol / L ammonium persulfate solution to retain the functional layer 20. After the corrosion is completed, the functional layer 20 is placed in deionized water for cleaning, and then a nitrogen gun is used to gently blow dry the deionized water remaining on the lower surface of the boron nitride layer 201 to leave a clean surface of the functional layer 20.

[0101] It can be understood that since the functional layer 20 includes a boron nitride layer 201 and a graphene layer 202, and the boron nitride layer 201 is located on the upper surface of the metal growth substrate 10, and the graphene layer 202 is located on the upper surface of the boron nitride layer 201, when the metal growth substrate 10 is removed, the boron nitride layer 201 located on the lower surface of the graphene layer 202 can also prevent the lower surface of the graphene layer 202 from directly contacting the chemical reagent, thereby preventing the lower surface of the graphene layer 202 from being corroded by the chemical reagent and causing loss or damage.

[0102] In step S502, refer to Figure 5 Step S502 and Figure 7 , providing a target substrate 30.

[0103] In step S503, refer to Figure 5 Step S503 and Figure 8 , transferring the functional layer 20 to the upper surface of the target substrate 30 .

[0104] In some examples, after the functional layer 20 is transferred to the upper surface of the target substrate 30 , the target substrate 30 may be placed on a heating plate at 100° C. and heated for 30 minutes to enhance the bonding force between the boron nitride layer 201 and the target substrate 30 .

[0105] In step S504, refer to Figure 5 Step S504 and Fig. 9 , the functional layer 20 is patterned to obtain a patterned functional layer 40.

[0106] In some examples, the process of patterning the functional layer 20 may be performed using a plasma etching process.

[0107] Optionally, a layer of photoresist can be spin-coated on the functional layer 20 on the upper surface of the target substrate 30, and after a series of processes such as baking, exposure, and development, a patterned photoresist is obtained. The above structure is then placed in a plasma cleaning machine and the surface of the functional layer 20 is bombarded with oxygen plasma to complete the patterning of the functional layer 20.

[0108] In one embodiment, Fig.10 As shown, after forming the functional layer on the upper surface of the metal growth substrate and before removing the metal growth substrate, the following steps may also be included:

[0109] S1001: forming a first supporting protective layer on the upper surface of the graphene layer;

[0110] S1002: forming a second supporting and protecting layer on the upper surface of the first supporting and protecting layer.

[0111] In step S1001, refer to Fig.10 Step S1001 and Fig.11 , a first supporting protection layer 50 is formed on the upper surface of the graphene layer 202 .

[0112] In some examples, the material of the first supporting protective layer 50 may include a polymer material such as photoresist, polymethyl methacrylate (PMMA), etc. It is understood that the first supporting protective layer 50 has a high strength, which can prevent the graphene layer 202 in the functional layer 20 from being wrinkled or damaged during the transfer to the target substrate 30. At the same time, the first supporting protective layer 50 can prevent the upper surface of the graphene layer 202 from being corroded by chemical reagents and damaged during the removal of the metal growth substrate 10.

[0113] Preferably, the first supporting protective layer 50 may be a photoresist. It is understood that after the functional layer 20 is transferred to the upper surface of the target substrate 30, before the functional layer 20 is patterned, it is not necessary to re-apply the photoresist, but the first supporting protective layer 50 may be directly patterned, thereby saving process steps.

[0114] Optionally, taking the first supporting protective layer 50 as a photoresist as an example, the step of forming the first supporting protective layer 50 on the upper surface of the graphene layer 202 may include: spin coating the photoresist onto the upper surface of the graphene layer 202, the spin coating thickness is 1.6um, the spin coating metering is 4mL, the low speed is 500r / min, the time is 5s, the high speed is 3000r / min, and the time is 60s. After the spin coating is completed, the resulting structure is placed on a 100°C heating plate for baking to cure the photoresist.

[0115] Optionally, the photoresist may be 304 positive photoresist.

[0116] In step S1002, refer to Fig.10 Step S1002 and Fig.12 , a second supporting and protecting layer 60 is formed on the upper surface of the first supporting and protecting layer 50 .

[0117] In some examples, the second supporting protective layer 60 may include a flexible polymer film such as a PET film, a PI film, a TPU film, a PP film, a PVC film, a CPP film, an OPP film, a BOPP film, a MOPP film or a PE film. Preferably, the second supporting protective layer 60 may be a PET film. It is understood that the second supporting protective layer 60 may prevent the first supporting protective layer 50 from being wrinkled or damaged during the transfer to the target substrate 30.

[0118] Optionally, taking the second supporting protective layer 60 as a PET film as an example, the step of forming the second supporting protective layer 60 on the upper surface of the first supporting protective layer 50 may include: placing the PET film on the upper surface of the first supporting protective layer 50, and using a glass plate to gently press the PET film to make the PET film and the first supporting protective layer 50 fit tightly.

[0119] Based on the above embodiments, in one embodiment, after the functional layer 20 is transferred to the upper surface of the target substrate 30 and before the functional layer 20 is patterned, the process may further include: removing the second supporting protective layer 60 and the first supporting protective layer 50 .

[0120] It can be understood that since the second supporting protective layer 60 is a flexible polymer film and the first supporting protective layer 50 is a polymer material, the interaction force between the first supporting protective layer 50 and the graphene layer 202 is much greater than the interaction force between the second supporting protective layer 60 and the first supporting protective layer 50. Therefore, the second supporting protective layer 60 can be easily peeled off from the upper surface of the first supporting protective layer 50, and the second supporting protective layer 60 can be removed.

[0121] In addition, if the first supporting protective layer 50 is other polymer materials (such as PMMA), it is necessary to remove the first supporting protective layer 50 and then pattern the functional layer 20; if the first supporting protective layer 50 is photoresist, there is no need to remove the first supporting protective layer 50, and the functional layer 20 can be directly patterned, thereby saving process steps.

[0122] In one embodiment, Fig.13 As shown, the functional layer is patterned to obtain a patterned functional layer; the metal growth substrate is removed, and the patterned functional layer is transferred to the upper surface of the target substrate, and the following steps may also be included:

[0123] S1301: forming a photoresist layer on the upper surface of the graphene layer;

[0124] S1302: patterning the photoresist layer to obtain a patterned photoresist layer;

[0125] S1303: etching the functional layer based on the patterned photoresist layer to obtain a patterned functional layer;

[0126] S1304: removing the metal growth substrate;

[0127] S1305: Transferring the patterned functional layer to the upper surface of the target substrate.

[0128] In step S1301, refer to Fig.13 Step S1301 and Fig.14 , a photoresist layer 70 is formed on the upper surface of the graphene layer 202 .

[0129] In some examples, photoresist layer 70 may be 304 positive photoresist.

[0130] Optionally, the photoresist layer 70 can be spin-coated onto the upper surface of the graphene layer 202, with a spin coating thickness of 1.6 um, a spin coating metering of 4 mL, a low speed of 500 r / min, a time of 5 s, and a high speed of 3000 r / min, a time of 60 s. After the spin coating is completed, the resulting structure is placed on a 100° C. hot plate for baking to cure the photoresist layer 70.

[0131] In step S1302, refer to Fig.13 Step S1302 and Fig.15 , the photoresist layer 70 is patterned to obtain a patterned photoresist layer 701 .

[0132] Optionally, the photoresist layer 70 may be exposed using an ultraviolet lithography machine, with an exposure time of 6 seconds and an exposure meter of 10 W. After the exposure is completed, the photoresist layer 70 is immersed in a 3080 developer and developed for 60 seconds to obtain a patterned photoresist layer 701 .

[0133] In step S1303, refer to Fig.13 Step S1303 and Fig.16 , the functional layer 20 is etched based on the patterned photoresist layer 701 to obtain a patterned functional layer 40 .

[0134] In some examples, a plasma etching process may be used to obtain the patterned functional layer 40 .

[0135] Optionally, the upper surface of the functional layer 20 can be bombarded with oxygen plasma in a plasma cleaning machine to obtain a patterned functional layer 40. Since the functional layer 20 is patterned before being transferred to the target substrate 30, the photoresist layer 70 is not soaked in any chemical reagents, thereby ensuring that the photoresist layer 70 will not be damaged, and thus the success rate of lithography is very high.

[0136] In step S1304, refer to Fig.13 Step S1304 and Fig.17 , removing the metal growth substrate 10.

[0137] In some examples, metal growth substrate 10 may be removed using chemical agents.

[0138] Optionally, taking the metal growth substrate 10 as copper foil as an example, the copper foil can be corroded using a 0.1 mol / L ammonium persulfate solution to retain the functional layer 20. After the corrosion is completed, the functional layer 20 is placed in deionized water for cleaning, and then a nitrogen gun is used to gently blow dry the deionized water remaining on the lower surface of the boron nitride layer 201 to leave a clean surface of the functional layer 20.

[0139] It can be understood that since the patterned functional layer 40 includes a patterned boron nitride layer 401 and a patterned graphene layer 402, and the patterned boron nitride layer 401 is located on the upper surface of the metal growth substrate 10, and the patterned graphene layer 402 is located on the upper surface of the patterned boron nitride layer 401, when the metal growth substrate 10 is removed, the patterned boron nitride layer 401 located on the lower surface of the patterned graphene layer 402 can also prevent the lower surface of the patterned graphene layer 402 from directly contacting the chemical reagent, thereby preventing the lower surface of the patterned graphene layer 402 from being corroded by the chemical reagent and causing loss or damage.

[0140] In step S1305, refer to Fig.13 Step S1305 and Fig.18 , transferring the patterned functional layer 40 to the upper surface of the target substrate 30 .

[0141] In some examples, after the patterned functional layer 40 is transferred to the upper surface of the target substrate 30 , the target substrate 30 may be placed on a heating plate at 100° C. and heated for 30 minutes to enhance the bonding force between the patterned boron nitride layer 401 and the target substrate 30 .

[0142] In one embodiment, Fig.19 As shown, after etching the functional layer 20 based on the patterned photoresist layer 701 and before removing the metal growth substrate 10 , the process may further include: forming a supporting protection layer 80 on the upper surface of the patterned photoresist layer 701 .

[0143] In some examples, the supporting protective layer 80 may include a flexible polymer film such as a PET film, a PI film, a TPU film, a PP film, a PVC film, a CPP film, an OPP film, a BOPP film, a MOPP film or a PE film. Preferably, the supporting protective layer 80 may be a PET film. It is understood that the supporting protective layer 80 may prevent the patterned photoresist layer 701 from being wrinkled or damaged during the transfer to the target substrate 30.

[0144] Optionally, taking the supporting protective layer 80 as a PET film as an example, the step of forming the supporting protective layer 80 on the upper surface of the patterned photoresist layer 701 may include: placing the PET film on the upper surface of the patterned photoresist layer 701, and gently pressing the PET film with a glass plate to make the PET film and the patterned photoresist layer 701 fit tightly.

[0145] On the basis of the above embodiments, in one embodiment, after the patterned functional layer 40 is transferred to the upper surface of the target substrate 30 , the method further includes: removing the supporting protection layer 80 and the patterned photoresist layer 701 .

[0146] It can be understood that since the supporting protective layer 80 is a flexible polymer film and the patterned photoresist layer 701 is a polymer material, the interaction force between the patterned photoresist layer 701 and the graphene layer 202 is much greater than the interaction force between the supporting protective layer 80 and the patterned photoresist layer 701. Therefore, the supporting protective layer 80 can be easily peeled off from the upper surface of the patterned photoresist layer 701, and the supporting protective layer 80 can be removed.

[0147] In one embodiment, Fig. 20 As shown, after the functional layer 20 is patterned to obtain the patterned functional layer 40, the following steps may also be included:

[0148] A first electrode 601 and a second electrode 602 are formed on the upper surface of the patterned graphene layer 402 . The first electrode 601 is located on one side of the patterned graphene layer 402 , and the second electrode 602 is located on a side of the patterned graphene layer 402 away from the first electrode 601 .

[0149] Understandably, Fig. 20 This is only an example diagram of one position of the first electrode 601 and the second electrode 602. In actual application scenarios, Fig. 20 The positions of the first electrode 601 and the second electrode 602 can also be interchanged.

[0150] In some examples, the material of the first electrode 601 and the second electrode 602 may include metals such as Au, Cr, or Au / Cr alloy.

[0151] Optionally, forming the first electrode 601 and the second electrode 602 on the upper surface of the patterned graphene layer 402 may also include the following steps: spin coating a layer of photoresist on the patterned functional layer 40 again, and performing baking, exposure and development process steps to obtain a patterned photoresist, while exposing a portion of the patterned graphene layer 402, and then forming an electrode layer by a vapor deposition process, vapor-depositing 5nm Cr and 45nm Au on the upper surface of the patterned photoresist and the exposed upper surface of the patterned graphene layer 402 in an electron beam evaporator, and then removing the patterned photoresist and the electrode layer on the upper surface of the patterned photoresist by a lift-off process, retaining the electrode layer on the upper surface of the exposed patterned graphene layer 402, so as to form the first electrode 601 and the second electrode 602 on the upper surface of the patterned graphene layer 402.

[0152] Please continue reading Fig. 9 The present invention also provides a biosensor, which includes: a target substrate 30; a patterned functional layer 40, which is located on the upper surface of the target substrate 30, and the patterned functional layer 40 includes a patterned boron nitride layer 401 and a patterned graphene layer 402, the patterned boron nitride layer 401 is located on the upper surface of the target substrate 30, and the patterned graphene layer 402 is located on the upper surface of the patterned boron nitride layer 401.

[0153] The biosensor of the present invention comprises: a target substrate 30; a patterned functional layer 40, which is located on the upper surface of the target substrate 30. Since the patterned functional layer 40 is a double-layer structure including a patterned boron nitride layer 401 and a patterned graphene layer 402, and the patterned boron nitride layer 401 is located on the upper surface of the target substrate 30, and the patterned graphene layer 402 is located on the upper surface of the patterned boron nitride layer 401, the strength is higher than that of a single graphene layer 202. Therefore, in the process of transferring the functional layer 20 to the target substrate 30, the graphene layer 202 can be prevented from being wrinkled or damaged, thereby preventing the detection sensitivity of the biosensor from decreasing.

[0154] In one embodiment, see Fig. 20 The biosensor also includes: a first electrode 601, located on the upper surface of the patterned graphene layer 402 and on one side of the patterned graphene layer 402; a second electrode 602, located on the upper surface of the patterned graphene layer 402 and on a side of the patterned graphene layer 402 away from the first electrode 601.

[0155] Understandably, Fig. 20 This is only an example diagram of one position of the first electrode 601 and the second electrode 602. In actual application scenarios, Fig. 20 The positions of the first electrode 601 and the second electrode 602 can also be interchanged.

[0156] In some examples, the material of the first electrode 601 and the second electrode 602 may include metals such as Au, Cr, or Au / Cr alloy.

[0157] In one embodiment, the target substrate 30 may include a silicon wafer, a silicon carbide substrate, or a gallium nitride substrate.

[0158] It should be understood that, although the various steps in the flow chart are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the figure may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0159] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing a biosensor, characterized in that: The preparation method of the biosensor comprises: providing a metal growth substrate; Forming a functional layer on the upper surface of the metal growth substrate by a chemical vapor deposition process, wherein the functional layer includes a boron nitride layer and a graphene layer, wherein the boron nitride layer is formed on the upper surface of the metal growth substrate by a chemical vapor deposition process, and the graphene layer is formed on the upper surface of the boron nitride layer by a chemical vapor deposition process; Removing the metal growth substrate by using chemical reagents, transferring the functional layer to the upper surface of the target substrate, and then patterning the functional layer to obtain a patterned functional layer, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer; or Patterning the functional layer to obtain a patterned functional layer; removing the metal growth substrate using a chemical reagent, and transferring the patterned functional layer to the upper surface of the target substrate, wherein the patterned functional layer includes a patterned graphene layer and a patterned boron nitride layer; When the metal growth substrate is removed by using a chemical reagent, the chemical reagent does not directly contact the patterned graphene layer.

2. The method for preparing a biosensor according to claim 1, characterized in that: The removing of the metal growth substrate, transferring the functional layer to the upper surface of the target substrate and then patterning the functional layer to obtain a patterned functional layer comprises: removing the metal growth substrate; providing a target substrate; transferring the functional layer to the upper surface of the target substrate; The functional layer is patterned to obtain the patterned functional layer.

3. The method for preparing a biosensor according to claim 2, characterized in that: After forming a functional layer on the upper surface of the metal growth substrate and before removing the metal growth substrate, the method further includes: forming a first supporting protective layer on the upper surface of the graphene layer; forming a second supporting and protecting layer on the upper surface of the first supporting and protecting layer; After transferring the functional layer to the upper surface of the target substrate and before patterning the functional layer, the method further includes: The second supporting protective layer and the first supporting protective layer are removed.

4. The method for preparing a biosensor according to claim 1, characterized in that: The step of patterning the functional layer to obtain a patterned functional layer; removing the metal growth substrate, and transferring the patterned functional layer to the upper surface of a target substrate comprises: forming a photoresist layer on the upper surface of the graphene layer; Patterning the photoresist layer to obtain a patterned photoresist layer; Etching the functional layer based on the patterned photoresist layer to obtain the patterned functional layer; removing the metal growth substrate; The patterned functional layer is transferred to the upper surface of the target substrate.

5. The method for preparing a biosensor according to claim 4, characterized in that: After etching the functional layer based on the patterned photoresist layer and before removing the metal growth substrate, the method further includes: forming a supporting protective layer on the upper surface of the patterned photoresist layer; After transferring the patterned functional layer to the upper surface of the target substrate, the method further comprises: The supporting protection layer and the patterned photoresist layer are removed.

6. The method for preparing a biosensor according to any one of claims 1 to 5, characterized in that: The metal growth substrate includes copper foil.

7. The method for preparing a biosensor according to any one of claims 1 to 5, characterized in that: After the functional layer is graphed to obtain a graphed functional layer, the method further includes: A first electrode and a second electrode are formed on the upper surface of the patterned graphene layer, wherein the first electrode is located on one side of the patterned graphene layer, and the second electrode is located on a side of the patterned graphene layer away from the first electrode.

8. A biosensor, characterized in that: The biosensor is prepared by the method according to any one of claims 1 to 7, and the biosensor comprises: target substrate; A patterned functional layer is located on the upper surface of the target substrate, the patterned functional layer includes a patterned boron nitride layer and a patterned graphene layer, the patterned boron nitride layer is located on the upper surface of the target substrate, and the patterned graphene layer is formed on the upper surface of the patterned boron nitride layer by a chemical vapor deposition process; The patterned functional layer is obtained by forming a functional layer on the upper surface of a metal growth substrate, removing the metal growth substrate with a chemical reagent, transferring the functional layer to the upper surface of the target substrate, and then patterning the functional layer; or by forming a functional layer on the upper surface of a metal growth substrate, patterning the functional layer to obtain a patterned functional layer, removing the metal growth substrate with a chemical reagent, and transferring the patterned functional layer to the upper surface of the target substrate; The functional layer is formed on the metal growth substrate by a chemical vapor deposition process; when a chemical reagent is used to remove the metal growth substrate, the chemical reagent does not directly contact the patterned graphene layer.

9. The biosensor according to claim 8, characterized in that The biosensor further comprises: A first electrode is located on the upper surface of the patterned graphene layer and on one side of the patterned graphene layer; The second electrode is located on the upper surface of the patterned graphene layer and on a side of the patterned graphene layer away from the first electrode.

10. The biosensor according to claim 8, characterized in that The target substrate includes a silicon wafer, a silicon carbide substrate or a gallium nitride substrate.

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