Biosensor based on graphene bi-material grid tunneling field effect transistor

Abstract

The invention relates to the field of biosensors, in particular to a biosensor based on a graphene bi-material grid tunneling field effect transistor, which comprises a graphene channel, a source electrode, a drain electrode, an insulating dielectric layer, a silicon substrate, a grid dielectric layer, a first grid electrode, a second grid electrode, a biological dielectric layer and a biological nano cavity, the silicon substrate, the insulating dielectric layer, the graphene channel and the gate dielectric layer are sequentially stacked from bottom to top; the source electrode and the drain electrode are located on the left and right sides of the graphene channel; the biological dielectric layer and the second grid electrode are stacked at the left end and the right end of the upper surface of the grid dielectric layer respectively, and the biological dielectric layer is hollowed out to form a biological nano cavity; the first gate layer is stacked on the upper surface of the biological dielectric layer; the metal material of the first gate and the metal material of the second gate have different work functions. According to the invention, the energy band of the graphene channel can be comprehensively regulated and controlled, energy band tunneling between graphene can be realized without doping the graphene, the manufacturing process is relatively simple, and the sensitivity is high.

Description

Technical Field

[0001] The present invention relates to the field of biosensors, and in particular to a biosensor based on a graphene dual-material gate tunneling field effect transistor. Background Art

[0002] As an emerging two-dimensional material, graphene has shown great advantages in the field of biosensing. Its high electron mobility and large specific surface area make graphene an ideal material for biosensors. Compared with traditional silicon-based sensors, the introduction of graphene materials enables biosensors to show faster response speed and higher sensitivity, and can detect low-concentration biomolecules to a greater extent.

[0003] However, due to its high electron-hole concentration and zero band gap characteristics, graphene materials exhibit bipolar properties during detection. Therefore, graphene biosensors under traditional structures often judge the type of organisms based on the displacement of the Dirac point (the lowest current point in the transfer curve) of their transfer curve, but this method has low detection sensitivity.

[0004] To this end, biosensors using graphene and other materials as tunneling junctions have gradually developed. By studying the tunneling process, the device has a higher switching current ratio and higher sensitivity to biological detection. However, this structure is extremely complex in dealing with the interface contact problem between the two materials, and generally requires high doping of the material to meet the tunneling requirements, and the manufacturing process is relatively complicated.

[0005] Therefore, there is an urgent need to solve the problem that biosensors require high doping of materials to meet tunneling requirements and the manufacturing process is relatively complicated. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a biosensor based on a graphene dual-material gate tunneling field-effect transistor, which uses two metal materials with different work functions as gates to comprehensively regulate the energy band of the graphene channel. The energy band tunneling between graphenes can be achieved without doping the graphene. The manufacturing process is relatively simple and the sensitivity is high.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: a biosensor based on a graphene dual-material gate tunneling field effect transistor, comprising a graphene channel, a source, a drain, an insulating dielectric layer, a silicon substrate, a gate dielectric layer, a first gate, a second gate, a biological dielectric layer and a biological nanocavity; wherein,

[0008] The silicon substrate, the insulating dielectric layer, the graphene channel and the gate dielectric layer are stacked in sequence from bottom to top;

[0009] The source electrode is located on the left side of the graphene channel, and the drain electrode is located on the right side of the graphene channel. Both the source electrode and the drain electrode are sandwiched between the insulating dielectric layer and the gate dielectric layer, and both are in Schottky contact with the graphene channel.

[0010] The biological dielectric layer is stacked on the left end of the upper surface of the gate dielectric layer and is hollowed out to form the biological nanocavity;

[0011] The first gate is stacked on the upper surface of the biological dielectric layer, and the second gate is stacked on the right end of the upper surface of the gate dielectric layer, with a gap between the second gate and the biological dielectric layer;

[0012] The work function of the metal material of the source electrode is greater than the work function of the metal material of the drain electrode, and the work functions of the metal material of the first gate electrode and the metal material of the second gate electrode are different.

[0013] Furthermore, the source electrode is made of cobalt metal material, and the drain electrode is made of hafnium metal material.

[0014] Furthermore, the graphene channel is made of undoped intrinsic graphene material, has a length of 100 nm and a thickness of 5-10 nm.

[0015] Furthermore, the material of the gate dielectric layer is hafnium dioxide.

[0016] Furthermore, a horizontal distance of 1-10 nm exists between the first gate and the second gate.

[0017] Furthermore, the first gate is made of copper metal material, and the second gate is made of titanium metal material.

[0018] Furthermore, the first gate voltage range is set to be between -0.1V and 0.1V.

[0019] The present invention also relates to a method for preparing a biosensor based on a graphene dual-material gate tunneling field effect transistor, comprising:

[0020] Step S1: using a silicon wafer as a silicon substrate, a silicon dioxide film with uniform thickness is grown on the surface of the silicon substrate by thermal oxidation method. After the growth is completed, the temperature is adjusted to 800-1100° C. for 30 minutes, and the silicon dioxide substrate is annealed under nitrogen protection to obtain an insulating dielectric layer;

[0021] Step S2, using copper foil as a substrate, cracking methane at a high temperature of 1000° C. to deposit carbon atoms on the copper foil, and determining the deposition time according to the thickness of graphene;

[0022] Step S3, applying a PMMA film on the graphene surface on the copper foil to adhere the graphene deposited on the copper foil, and removing the copper foil by wet etching. At this time, the graphene is still adhered to the PMMA surface.

[0023] Step S4, transferring the PMMA film and the graphene thereon to the insulating dielectric layer, and removing the PMMA film with an acetone solution;

[0024] Step S5, using photolithography technology to define source and drain patterns at both ends of the graphene, depositing metal materials of the source and drain by electron beam evaporation technology, and finally performing annealing treatment under nitrogen protection at a temperature of 300-400° C. for 30 minutes to improve the contact performance between the metal and the graphene;

[0025] Step S6, depositing a gate dielectric layer and a biological dielectric layer in sequence on the graphene surface;

[0026] Step S7: using photolithography technology to define the gate pattern, using electron beam evaporation technology to deposit the first gate on the biological medium layer, and performing annealing.

[0027] Step S8, using dry etching to etch a nano-bio cavity in the bio-medium layer, using photolithography to define a pattern on the bio-medium layer, using photoresist to protect the area that does not need to be etched, selecting hydrogen fluoride gas to etch it, and after completion, using acetone solution to remove the photoresist;

[0028] Step S9, depositing a second gate on the gate dielectric layer next to the bio-nano cavity;

[0029] Step S10, cleaning the entire device and removing residual photoresist and contaminants, and finally annealing in a nitrogen environment at a temperature of 200° C. for 30 minutes to improve the electrical performance and stability of the graphene field effect transistor.

[0030] After adopting the above technical scheme, the present invention adopts intrinsic graphene as a conductive channel, and while not doping the graphene, a source metal with a high work function and a drain metal with a low work function are cited to introduce a P region and an N region into the source region and the drain region of the graphene, respectively, to create a PIN condition satisfied by tunneling, and two metals of different materials are used as gates. Under the regulation of the two gate metals with different work functions on the graphene channel, the graphene channel has tunneling conditions. Compared with the traditional single-gate graphene field effect transistor, the structure does not need to observe the slight change of the Dirac point in the transfer curve to distinguish the category of the organism, but only needs to compare the saturation current output by the sensor, and the structure has a lower off current and a higher switching current ratio, which overcomes the problem that the switching current ratio of graphene is only a few hundred, and has a higher sensitivity to biological detection. In addition, compared with the traditional silicon-graphene heterojunction tunneling field effect transistor, the biosensor of the present invention does not need to consider the doping and interface state problems, so the manufacturing process is relatively simple, and because a full graphene channel is used, it has a lower subthreshold swing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of a biosensor based on a graphene dual-material gate tunneling field-effect transistor of the present invention;

[0032] Figure 2 is an energy band diagram of the channel of the biosensor of the present invention under different biological conditions;

[0033] Figure 3 A diagram showing the tunneling distance and tunneling rate of electrons in the channel tunneling region of the biosensor of the present invention under different biological conditions;

[0034] Figure 4 is a transfer curve diagram of the biosensor in Example 1 of the present invention under different biological conditions;

[0035] Figure 5 is a transfer curve diagram of the biosensor in Example 2 of the present invention under different biological conditions;

[0036] Figure 6 A comparison diagram of the transfer curves of the biosensor in Example 1 and the conventional silicon-graphene heterojunction tunneling in Comparative Example 1 under the condition of a biological dielectric constant k=6;

[0037] Figure 1 In the figure: 1. graphene channel; 2. source; 3. drain; 4. insulating dielectric layer; 5. silicon substrate; 6. gate dielectric layer; 7. first gate; 8. second gate; 9. biological dielectric layer; 10. biological nanocavity. DETAILED DESCRIPTION

[0038] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0039] like Figure 1 As shown, a biosensor based on a graphene dual-material gate tunneling field effect transistor comprises a graphene channel 1, a source 2, a drain 3, an insulating dielectric layer 4, a silicon substrate 5, a gate dielectric layer 6, a first gate 7, a second gate 8, a biological dielectric layer 9 and a biological nanocavity 10; wherein,

[0040] The silicon substrate 5, the insulating dielectric layer 4, the graphene channel 1 and the gate dielectric layer 6 are stacked in sequence from bottom to top;

[0041] The source electrode 2 is located on the left side of the graphene channel 1, and the drain electrode 3 is located on the right side of the graphene channel 1. Both the source electrode 2 and the drain electrode 3 are sandwiched between the insulating dielectric layer 4 and the gate dielectric layer 6, and both are in Schottky contact with the graphene channel 1.

[0042] The biological dielectric layer 9 is stacked on the left end of the upper surface of the gate dielectric layer 6 and is hollowed out to form a biological nanocavity 10. The biological nanocavity 10 is used to accommodate the detection organisms. Different organisms are given different dielectric constants k, and the dielectric constants k are used to distinguish the types of organisms.

[0043] The first gate 7 is stacked on the upper surface of the biological medium layer 9, and the second gate 8 is stacked on the right end of the upper surface of the gate dielectric layer 6, with a gap between the first gate 7 and the second gate 8. The horizontal spacing between the first gate 7 and the second gate 8 can be 1-10nm.

[0044] In this embodiment, in order to create an electron-hole concentration satisfied by tunneling, the work function of the metal material of the source 2 is greater than the work function of the metal material of the drain 3. The source 2 can adopt a cobalt metal material (Co) with a work function of 5eV to create a P region in the source region. The drain 3 can adopt a hafnium metal material (Hf) with a work function of 3.9eV to create an N region in the drain region. In order to make the carriers in the channel evenly distributed, the source and drain metals are of the same size, with a size of 10nm×5nm.

[0045] In this embodiment, intrinsic graphene is used as a conductive channel. Without doping the graphene, in order to make the graphene channel 1 have tunneling conditions, the metal material of the first gate 7 and the metal material of the second gate 8 have different work functions. The first gate 7 can be made of copper metal material (Cu) with a work function of 4.65eV, and the second gate 8 can be made of titanium metal material (Ti) with a work function of 4.33eV. The voltage range of the first gate 7 should be set to -0.1V to 0.1V.

[0046] In this embodiment, the graphene channel 1 is made of undoped intrinsic graphene material, has a length of 100 nm and a thickness of 5-10 nm.

[0047] In this embodiment, the gate dielectric layer 6 is closely attached to the graphene 1 and covers the source and drain metals. It is made of an insulating material with a relatively high dielectric constant, such as hafnium dioxide (HfO2), and has a thickness of 1-3 nm.

[0048] In this embodiment, the bio-medium layer 9 is a general oxide, which can be silicon dioxide, aluminum oxide, hafnium dioxide, etc. The bio-nano cavity 10 is the detection position of the biomolecules, which is filled with air when not being detected, and has a size of 35nm×10nm.

[0049] The biosensor in this embodiment can detect the concentration of a single organism based on the dielectric constant after the single organism is filled in the bio-nano cavity 10, and can also distinguish each single organism based on the dielectric constant.

[0050] The method for preparing the biosensor based on the graphene dual-material gate tunneling field effect transistor involved in the above embodiment comprises:

[0051] Step S1: A silicon wafer with a flat surface and high resistivity is used as a silicon substrate 5, and a silicon dioxide film with uniform thickness is grown on the surface of the silicon substrate 5 by a thermal oxidation method. After the growth is completed, the temperature is adjusted to 800-1100° C. for 30 minutes, and the silicon dioxide substrate 5 is annealed under nitrogen protection to obtain an insulating dielectric layer 4;

[0052] Step S2, using copper foil as a substrate, cracking methane at a high temperature of 1000° C. to deposit carbon atoms on the copper foil, and determining the deposition time according to the thickness of graphene;

[0053] Step S3, applying a polymethyl methacrylate (PMMA) film on the graphene surface on the copper foil to adhere the graphene deposited on the copper foil, and removing the copper foil by wet etching. At this time, the graphene is still adhered to the PMMA surface.

[0054] Step S4, transferring the PMMA film and the graphene thereon to the insulating dielectric layer 4, and removing the PMMA film with an acetone solution;

[0055] Step S5, using photolithography technology to define the source and drain 3 patterns at both ends of the graphene, depositing metal electrode materials by electron beam evaporation technology, depositing cobalt metal on the source 2 and hafnium metal on the drain 3, with a length of 10nm and a thickness of 5nm, and finally performing annealing treatment under nitrogen protection at a temperature of 300-400°C for 30 minutes to improve the contact performance between the metal and the graphene;

[0056] Step S6, depositing a gate dielectric layer 6 and a biological dielectric layer 9 on the graphene surface in sequence by atomic layer deposition (ALD), wherein the gate dielectric layer 6 has a thickness of 1-3 nm, and the biological dielectric layer 9 has a length of 40-48 nm and a thickness of 10 nm.

[0057] Step S7: using photolithography technology to define the gate pattern, using electron beam evaporation technology to deposit copper, the material of the first gate 7, on the biological dielectric layer 9, and performing annealing.

[0058] Step S8, using dry etching to etch a nano-bio cavity 10 with a length of 30-38 nm and a thickness of 10 nm in the bio-medium layer 9, using photolithography to define a pattern on the bio-medium layer 9, using photoresist to protect the area that does not need to be etched, selecting hydrogen fluoride gas to etch it, and after completion, using acetone solution to remove the photoresist;

[0059] Step S9, depositing titanium, a material of the second gate 8, on the gate dielectric layer 6 next to the bio-nano cavity 10;

[0060] Step S10, cleaning the entire device and removing residual photoresist and contaminants, and finally annealing in a nitrogen environment at a temperature of 200° C. for 30 minutes to improve the electrical performance and stability of the graphene field effect transistor.

[0061] The working principle of the biosensor based on the graphene dual-material gate tunneling field effect transistor involved in the above embodiment is:

[0062] Intrinsic graphene is used as a conductive channel. While graphene is not doped, a source metal with a high work function and a drain metal with a low work function are introduced to introduce a P region and an N region into the source region and the drain region of the graphene respectively, so as to create a PIN condition satisfied by tunneling. Then, two metals of different materials are used as gates. Under the modulation of different work functions of the gate metal, the energy band of the graphene channel 1 shows different degrees of bending, so that the structure better meets the tunneling condition. By introducing a biological nanocavity 10 under the first gate 7, the graphene energy band under the influence of the first gate 7 has different degrees of bending under different dielectric constants of the organism, resulting in different tunneling distances of electrons in the channel when detecting different organisms, thereby affecting the size of the tunneling current. By comparing the saturation current of the sensor during biological detection, the type of the organism can be further identified. Due to the different tunneling distances of electrons, the saturation current of the sensor for each organism is greatly different, so it has a higher sensitivity to biological detection.

[0063] Figure 2The energy band diagram of the channel of the biosensor under different biological conditions (under the same biological dielectric constant, the same color is used to represent the conduction band and the valence band, and the conduction band is located above the valence band). The source 2 voltage is 0V, the drain 3 voltage is 0.1V, the first gate 7 voltage is 0V, and the second gate 8 voltage starts from 0V with a step size of 0.01V and is finally set to 0.5V. When tunneling occurs, electrons tunnel from the valence band near the source region to the conduction band to the right, and the tunneling mainly occurs at the position where the horizontal coordinate x is 0.04nm, from Figure 2 It can be seen that the sensor has a shorter tunneling distance at this position under high-k conditions. It can also be seen that under different biological conditions, the bending degree of the graphene band under the control of the first gate 7 is different. This is due to the different dielectric constants k of the biological nanocavity 10. According to the effective capacitance formula:

[0064]

[0065] Among them, C be is the effective capacitance of the bio-nano cavity 10, k is the dielectric constant of the organism to be detected, t b is the thickness of the bio-nano cavity 10 .

[0066] It can also be seen that in the case of high dielectric constant k, the effective capacitance of the bio-nano cavity is larger, and at this time, the first gate 7 has a more obvious control over the channel energy band and a greater degree of bending. Since the gate dielectric layer 6 uses an oxide layer with a higher dielectric constant, when a voltage is applied to the second gate 8, the control force on the energy band in the channel is much greater than the control force of the first gate 7 on the channel, so the energy band under the influence of the second gate 8 is a horizontal line and does not bend.

[0067] The area between the first gate 7 and the second gate 8 in the graphene channel 1 is the main area for electron tunneling. The electron tunneling distance and the tunneling rate are as follows: Figure 3 As shown in Figure 2, for organisms with a dielectric constant of k = 12, the electron tunneling distance is shortened from 17.5 nm to 8.5 nm, and the tunneling rate is reduced from 2.18×10 26 / (cm 2 ·s) increased to 1.37×10 30 / (cm 2 ·s), the tunneling distance is shortened by 9nm, but the electron tunneling rate is increased by 4 orders of magnitude.

[0068] The above biosensor is described in detail below through specific embodiments and simulation processes.

[0069] In computer simulation software, we use different dielectric constants k to distinguish different biomolecules. When dielectric constant k = 1, it means that there is no organism to be detected in the bio-nano cavity, but air; k = 1.5, 2.6, 6, 12 means that the bio-nano cavity contains organisms with similar dielectric constants. The calculation formula of the biosensor sensitivity is the ratio of the saturation current of the sensor when there is an organism to be detected to the saturation current when there is no organism to be detected.

[0070] Embodiment 1

[0071] In a biosensor based on a graphene dual-material gate tunneling field effect transistor, the length of the bio-nano cavity 10 is 35 nm, the horizontal spacing between the first gate 7 and the second gate 8 is 5 nm, the voltage of the first gate 8 is set to 0 V, and the thickness of the gate dielectric layer 6 is 1 nm.

[0072] In the computer software modeling and simulation, we simulated the biosensor under different biological conditions, focusing on analyzing its transfer curve. The simulation results are as follows: Figure 4 When the biosensor is turned off, only 10 -13 A / μm. Moreover, under the biological conditions of air k=1 and dielectric constant k=12, the currents of 8.58×10 -11 A / μm and 1.15×10 -6 A / μm saturation current, with a high 4 sensitivity.

[0073] Embodiment 2

[0074] In a biosensor based on a graphene dual-material gate tunneling field effect transistor, the difference from the first embodiment is that the length of the bio-nano cavity 10 is 38nm, the horizontal distance between the first gate and the second gate is 2nm, and the voltage of the first gate 8 is set to -0.1V.

[0075] In the computer software modeling and simulation, we simulated the biosensor under different biological conditions, focusing on analyzing its transfer curve. The simulation results are as follows: Figure 5 When the biosensor is turned off, only 10 -13 A / μm, and under the biological conditions of air k=1 and dielectric constant k=12, the currents are 6.27×10 -10 A / μm and 6.32×10 -6 A / μm saturation current, with a high 4 sensitivity.

[0076] Comparative Example 1

[0077] A biosensor is a traditional silicon-graphene heterojunction tunneling structure. This structure requires the introduction of 1×10 20 cm -3 Heavy P doping and introduction of 5×10 18 cm -3 N doping is required. In addition, the interface state doping problem needs to be considered, and the manufacturing process is complicated.

[0078] Figure 6 The figure is a comparison of the transfer curves of the biosensors in Example 1 and Comparative Example 1 under the condition of a biological dielectric constant k=6. It can be seen from the comparison that Example 1 and Comparative Example 1 have the same off current, but Example 1 only needs a gate voltage increment of 0.2V to make the device reach the saturation current, and has a smaller subthreshold swing (subthreshold swing refers to the change in gate voltage when the current increases by one order of magnitude when the device is turned off to fully turned on). When the device has a smaller subthreshold swing, it can respond quickly to a smaller gate voltage change, which means that even a small change in biomolecules can cause a significant current change, making the sensor more sensitive to small changes in biological samples.

[0079] Comparative Example 2

[0080] A traditional single-gate graphene field-effect transistor, the transfer curve is "V" shaped, by observing the displacement of the Dirac point to analyze the biology, and the overall current is large, the saturation current can reach 10 -6 A / μm, the closing current is also 10 -8 A / μm, its on-off current ratio of only a few hundred limits its application in detection and sensitivity, and its sensitivity is far lower than that of the tunneling structure in Comparative Example 1.

[0081] Compared with Comparative Example 2, Example 1 and Example 2 overcome the problem of large overall current of traditional single-gate graphene field effect transistors, and also overcome the problem of its switching current ratio of only a few hundred, with a higher switching current ratio, and the sensor does not need to observe the slight changes in the Dirac point in the transfer curve like traditional devices to analyze biological categories, and the changes in the Dirac point are often very subtle and may be affected by factors such as environmental noise, resulting in low sensitivity. In contrast, Example 1 and Example 2 use the saturation current of the observed device to perform biological detection, which can more directly reflect the presence and concentration changes of biological molecules, avoid the inconspicuous movement of the Dirac point and the difficulty of detection, and therefore have higher sensitivity for biological detection.

[0082] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A biosensor based on a graphene dual-material gate tunneling field effect transistor, characterized in that: The invention comprises a graphene channel (1), a source electrode (2), a drain electrode (3), an insulating dielectric layer (4), a silicon substrate (5), a gate dielectric layer (6), a first gate electrode (7), a second gate electrode (8), a biological dielectric layer (9) and a biological nanocavity (10); wherein: The silicon substrate (5), the insulating dielectric layer (4), the graphene channel (1) and the gate dielectric layer (6) are stacked in sequence from bottom to top; The source electrode (2) is located on the left side of the graphene channel (1), and the drain electrode (3) is located on the right side of the graphene channel (1); the source electrode (2) and the drain electrode (3) are both sandwiched between the insulating dielectric layer (4) and the gate dielectric layer (6), and are both in Schottky contact with the graphene channel (1); The biological dielectric layer (9) is stacked on the left end of the upper surface of the gate dielectric layer (6) and is hollowed out to form the biological nanocavity (10); The first gate (7) is stacked on the upper surface of the biological medium layer (9), and the second gate (8) is stacked on the right end of the upper surface of the gate dielectric layer (6), with a gap between the second gate and the biological medium layer (9); The work function of the metal material of the source electrode (2) is greater than the work function of the metal material of the drain electrode (3), and the work functions of the metal material of the first gate electrode (7) and the metal material of the second gate electrode (8) are different.

2. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: The source electrode (2) is made of cobalt metal material, and the drain electrode (3) is made of hafnium metal material.

3. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: The graphene channel (1) is made of undoped intrinsic graphene material, has a length of 100 nm and a thickness of 5-10 nm.

4. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: The material of the gate dielectric layer (6) is hafnium dioxide.

5. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: There is a horizontal distance of 1-10 nm between the first gate (7) and the second gate (8).

6. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: The first grid electrode (7) is made of copper metal material, and the second grid electrode (8) is made of titanium metal material.

7. The biosensor based on graphene dual-material gate tunneling field effect transistor according to claim 1, characterized in that: The voltage range of the first gate (7) is set to be between -0.1V and 0.1V.

8. A method for preparing a biosensor based on a graphene dual-material gate tunneling field effect transistor according to any one of claims 1 to 7, characterized in that: include: Step S1: using a silicon wafer as a silicon substrate (5), a silicon dioxide film with uniform thickness is grown on the surface of the silicon substrate (5) by a thermal oxidation method. After the growth is completed, the temperature is adjusted to 800-1100° C. for 30 minutes, and the silicon dioxide substrate (5) is annealed under nitrogen protection to obtain an insulating dielectric layer (4); Step S2, using copper foil as a substrate, cracking methane at a high temperature of 1000° C. to deposit carbon atoms on the copper foil, and determining the deposition time according to the thickness of graphene; Step S3, applying a PMMA film on the graphene surface on the copper foil to adhere the graphene deposited on the copper foil, and removing the copper foil by wet etching. At this time, the graphene is still adhered to the PMMA surface. Step S4, transferring the PMMA film and the graphene thereon to the insulating dielectric layer (4), and removing the PMMA film using an acetone solution; Step S5, using photolithography technology to define the source and drain (3) patterns at both ends of the graphene, depositing the metal materials of the source (2) and the drain (3) by electron beam evaporation technology, and finally performing annealing treatment under nitrogen protection at a temperature of 300-400° C. for 30 minutes to improve the contact performance between the metal and the graphene; Step S6, depositing a gate dielectric layer (6) and a biological dielectric layer (9) in sequence on the graphene surface; Step S7: using photolithography technology to define the gate pattern, using electron beam evaporation technology to deposit the first gate (7) on the biological medium layer (9), and performing annealing treatment. Step S8, using dry etching to etch a nano-bio cavity in the bio-medium layer (9), using photolithography to define a pattern on the bio-medium layer (9), using photoresist to protect areas that do not need to be etched, selecting hydrogen fluoride gas to etch the areas, and after completion, using acetone solution to remove the photoresist; Step S9, depositing a second gate (8) on the gate dielectric layer (6) next to the bio-nano cavity (10); Step S10, cleaning the entire device and removing residual photoresist and contaminants, and finally annealing in a nitrogen environment at a temperature of 200° C. for 30 minutes to improve the electrical performance and stability of the graphene field effect transistor.

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