Biosensor of double-source L-type tunneling field effect transistor based on line tunneling and preparation method of biosensor
By designing an L-shaped channel and L-shaped oxide structure in the TFET biosensor and increasing the number of source regions and biological detection cavities, the problems of insufficient on-state current and sensitivity of existing TFET biosensors are solved, and high-performance biosensing effects are achieved.
Patent Information
- Application Number
- CN202510817569.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-18
- Publication Date
- 2025-09-16
AI Technical Summary
Existing TFET-based biosensors have problems with low on-state current and insufficient sensitivity, making it difficult to meet the needs of high-performance biosensing.
A biosensor based on a dual-source L-type tunneling field-effect transistor (FET) with line tunneling was designed. By adding source regions on both sides of the channel to form L-type oxides, the number of biodetection cavities was increased, thereby increasing the number of carriers and on-state current, and enhancing the modulation effect of biomolecules on the sensor.
The on-state current and sensitivity of the biosensor are significantly improved. Simulation results show that the on-state current can reach 5.8×10-2A/μm and the sensitivity can reach 1.4×106.
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Figure CN120651945A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a biosensor of a dual-source L-type tunneling field-effect transistor based on line tunneling and a preparation method thereof. Background Art
[0002] Biosensors have been widely used in medical diagnosis, food testing, environmental monitoring and other fields. FET (Field Effect Transistor)-based biosensors have attracted widespread attention due to their advantages of label-free detection, miniaturization, and good compatibility with CMOS (Complementary Metal Oxide Semiconductor) processes.
[0003] As the size of biosensors continues to shrink, FET-based biosensors are affected by the short-channel effect, resulting in increased power consumption and decreased sensitivity. To suppress the short-channel effect, researchers have proposed biosensors based on TFETs (Tunneling Field Effect Transistors). TFETs have a unique conduction mechanism with a subthreshold swing of less than 60mV / dec, smaller leakage current, and lower power consumption. However, TFETs also face the problems of small on-state current and low sensitivity, which affect the performance of biosensors.
[0004] Yunqi Wang et al. (Yunqi Wang, Simulation Study of Dual Metal-Gate Inverted T-Shaped TFET for Label-Free Biosensing[J].IEEE SENSORS JOURNAL, 2022, 22(19):18266-18272.) published a simulation study of a dual metal-gate inverted T-shaped TFET for label-free biosensing. The channel of the biosensor is T-shaped, with two drain regions located at the two ends of the T-shape, which effectively suppresses the bipolar effect. However, its on-state current is only on the order of 10 -5 , the on-state current is low.
[0005] Iman Chahardah Cherik et al. (Iman Chahardah Cherik, Fringe-fields-modulated double-gate tunnel-FET biosensor [J]. Scientific Reports, 2024, 14: 168.) published a fringe field modulated double-gate TFET biosensor. The biosensor forms a detection cavity by etching the sidewall between the source region and the gate. The biomolecules modulate the fringe electric field of the gate, thereby detecting the biomolecules. However, the process of the biosensor is simple, but the sensitivity is only 1.21×10 3 , the detection efficiency is low. Summary of the Invention
[0006] To overcome the shortcomings of the above-mentioned prior art, the present invention aims to provide a biosensor based on a dual-source L-type tunneling field-effect transistor (TEFET) with line tunneling and a method for preparing the same. By designing an L-shaped channel, the source regions are located on both sides of the channel, the number of source regions is increased, thereby increasing the number of carriers and the on-state current of the biosensor during operation. The present invention uses an L-shaped channel and an L-shaped oxide to form two biological detection cavities, effectively increasing the modulation effect of biomolecules on the biosensor and improving the sensitivity of the biosensor, thereby solving the technical problems of low on-state current and low sensitivity of tunneling field-effect transistor biosensors in the prior art.
[0007] In order to achieve the above object, the technical solution adopted by the present invention is:
[0008] A biosensor based on a dual-source L-type tunneling field-effect transistor (FET) using line tunneling comprises a substrate 8, a drain region 3, a vertical spacer 22, and a vertical source region 12 stacked from bottom to top; a horizontal spacer 21 and a horizontal source region 11 located on top of the substrate 8 are sequentially arranged on the vertical side of the drain region 3, and the horizontal source region 11 and the vertical source region 12 form a dual-source structure perpendicular to each other; an L-shaped channel 4, an L-shaped oxide 5, and an L-shaped gate electrode 7 are stacked on the inner side of the dual-source structure from bottom to top, and the L-shaped channel 4, the L-shaped oxide 5, and the L-shaped gate electrode 7 form two detection cavities, namely a horizontal detection cavity 61 and a vertical detection cavity 62, respectively, located on the horizontal and vertical sides of the L-shaped oxide 5.
[0009] The horizontal source region 11 and the vertical source region 12 are of exactly the same size and are perpendicular to each other, and the horizontal spacer 21 and the vertical spacer 22 are of exactly the same size and are perpendicular to each other; the aspect ratio of the drain region 3 is (3-8):2, and is exactly the same as the size of the horizontal spacer 21 and the vertical spacer 22; the horizontal source region 11 and the drain region 3 have the same width, and their length ratio is 4:3; the horizontal and vertical parts of the L-shaped channel 4 have a length ratio of 8:7:3 to the drain region 3; the horizontal and vertical parts of the L-shaped oxide 5 are exactly the same as the length of the drain region 3; the horizontal and vertical parts of the L-shaped gate electrode 7 have a length ratio of 6:5:3 to the drain region 3; the widths of the L-shaped channel 4, the L-shaped oxide 5 and the L-shaped gate electrode 7 are all the same, and the ratio to the length of the drain region 3 is 1:3.
[0010] The length of the substrate 8 is the sum of the lengths of the horizontal source region 11, the horizontal spacer 21, and the drain region 3, with a width of 20 nm and a length of 200-400 nm. The materials of the horizontal source region 11 and the vertical source region 12 are both germanium or gallium arsenide. The materials of the horizontal spacer 21 and the vertical spacer 22 are both silicon dioxide. The materials of the drain region 3, the channel 4, and the substrate 8 are all single crystal silicon. The material of the L-type oxide 5 is hafnium dioxide or titanium dioxide. The doping type of the horizontal source region 11 and the vertical source region 12 is P-type doping with a concentration of 1×10 19 cm -3 -1×10 20 cm -3 The doping type of the drain region 3 is N-type doping with a concentration of 1×10 17 cm -3 -1×10 18 cm -3 ; The work function of the L-shaped gate electrode 7 is 4.6eV-5.65eV.
[0011] A method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling comprises the following steps:
[0012] Step 1: Select a single crystal silicon substrate 8, and deposit germanium or gallium arsenide, silicon dioxide, and single crystal silicon on the substrate 8 in order from left to right to form a first germanium layer or a first gallium arsenide layer, a silicon dioxide layer, and a first silicon layer, respectively. The silicon dioxide layer serves as a horizontal spacer 21. Then, the first germanium layer or the first gallium arsenide layer is doped with P-type to form a horizontal source region 11. The first silicon layer is doped with N-type to form a drain region 3. After the doping is completed, thermal annealing is performed.
[0013] Step 2: depositing single crystal silicon on the horizontal source region 11, the horizontal spacer 21 and a portion of the drain region 3 to form a second silicon layer; etching the second silicon layer to form an L-shaped channel 4;
[0014] Step 3: Depositing silicon dioxide outside the L-shaped channel 4 to form a vertical spacer 22, then depositing germanium or gallium arsenide on the vertical spacer 22 to form a second germanium layer or a second gallium arsenide layer; then performing P-type doping on the second germanium layer or the second gallium arsenide layer to form a vertical source region 12, and performing thermal annealing after the doping is completed;
[0015] Step 4: depositing hafnium dioxide or titanium dioxide inside the L-shaped channel 4 to form a hafnium dioxide layer or a titanium dioxide layer; etching the hafnium dioxide layer or the titanium dioxide layer to form an L-shaped hafnium dioxide layer or a titanium dioxide layer;
[0016] Step 5: Depositing metal inside the L-shaped hafnium dioxide layer or titanium dioxide layer to form an L-shaped gate electrode 7; the metal is chromium, gold or platinum;
[0017] Step 6: Partially etch the L-shaped hafnium dioxide layer or titanium dioxide layer to form an L-shaped oxide 5 and detection cavities located on the horizontal and vertical sides of the L-shaped oxide 5 , namely, a horizontal detection cavity 61 and a vertical detection cavity 62 .
[0018] The concentration of the N-type doping is 1×10 17 cm -3 -1×10 18 cm -3 ; The concentration of P-type doping is 1×10 19 cm -3 -1×10 20 cm -3 .
[0019] The deposition process adopts a chemical vapor deposition process; the doping process adopts an ion implantation process; and the etching process adopts a dry etching process.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1) Compared with the biosensor proposed by Yunqi Wang et al. (the on-state current is on the order of 10 -5 Compared with the conventional biosensor, the present invention designs an L-shaped channel so that the source regions are located on both sides of the channel. The number of source regions is increased, thereby increasing the number of carriers and increasing the on-state current of the biosensor during operation. In addition, the gate electrode of the present invention covers both the source region and the channel, resulting in line tunneling with a larger tunneling area, further increasing the on-state current. Simulations have shown that the on-state current of the biosensor of the present invention can reach 5.8×10 -2 A / μm.
[0022] 2) Compared with the biosensor proposed by Iman Chahardah Cherik et al. (sensitivity of 1.21×10 3Compared with the conventional biosensor, the present invention has an L-shaped channel and the corresponding oxide is also L-shaped, thus forming two biological detection cavities, effectively increasing the modulation effect of biomolecules on the biosensor and improving the sensitivity of the biosensor. Simulation results show that the sensitivity of the biosensor of the present invention can reach 1.4×10 6 . BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 Schematic diagram of the structure of the biosensor based on line tunneling dual-source L-type tunneling field effect transistor of the present invention.
[0024] In the figure: horizontal source region 11 , vertical source region 12 , horizontal spacer 21 , vertical spacer 22 , drain region 3 , channel 4 , oxide 5 , horizontal detection cavity 61 , vertical detection cavity 62 , gate electrode 7 , substrate 8 .
[0025] Figure 2 The flowchart of the preparation of the biosensor of the present invention is shown in FIG.
[0026] Figure 3 This is a transfer characteristic curve diagram of the biosensor provided in Example 1. DETAILED DESCRIPTION
[0027] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.
[0028] like Figure 1 As shown, a biosensor based on a dual-source L-type tunneling field-effect transistor of line tunneling includes a substrate 8, a drain region 3, a vertical spacer 22, and a vertical source region 12 stacked from bottom to top; a horizontal spacer 21 and a horizontal source region 11 located on the top of the substrate 8 are sequentially arranged on the vertical side of the drain region 3, and the horizontal source region 11 and the vertical source region 12 form a dual-source structure perpendicular to each other; an L-shaped channel 4, an L-shaped oxide 5, and an L-shaped gate electrode 7 are stacked on the inner side of the dual-source structure from bottom to top, and the L-shaped channel 4, the L-shaped oxide 5 and the L-shaped gate electrode 7 form two detection cavities, namely a horizontal detection cavity 61 and a vertical detection cavity 62, respectively located on the horizontal side and the vertical side of the L-shaped oxide 5, for fixing biological molecules.
[0029] The length of the substrate 8 is the sum of the lengths of the horizontal source region 11, the horizontal spacer 21 and the drain region 3, with a width of 20 nm and a length of 200-400 nm; the horizontal source region 11 and the vertical source region 12 are of exactly the same size and perpendicular to each other, and the horizontal spacer 21 and the vertical spacer 22 are of exactly the same size and perpendicular to each other; the aspect ratio of the drain region 3 is (3-8):2, and is exactly the same as the size of the horizontal spacer 21 and the vertical spacer 22; the horizontal source region 11 and the drain region 3 have the same width, and their length ratio is 4:3; the horizontal and vertical parts of the L-shaped channel 4 have a length ratio of 8:7:3 to the drain region 3; the horizontal and vertical parts of the L-shaped oxide 5 are exactly the same length as the drain region 3; the horizontal and vertical parts of the L-shaped gate electrode 7 have a length ratio of 6:5:3 to the drain region 3; the widths of the L-shaped channel 4, the L-shaped oxide 5 and the L-shaped gate electrode 7 are all the same, and the ratio to the length of the drain region 3 is 1:3.
[0030] The material of the substrate 8 is single crystal silicon; the materials of the horizontal source region 11 and the vertical source region 12 are both germanium or gallium arsenide, and the doping type is P-type doping with a concentration of 1×10 19 cm -3 -1×10 20 cm -3 The horizontal spacer 21 and the vertical spacer 22 are made of silicon dioxide; the drain region 3 is made of single crystal silicon, with an N-type doping concentration of 1×10 17 cm -3 -1×10 18 cm -3 The material of the channel 4 is single crystal silicon; the material of the L-type oxide 5 is hafnium dioxide or titanium dioxide; the material of the L-type gate electrode 7 is chromium, gold or platinum, and the corresponding work functions are 4.6eV, 5.1eV or 5.65eV respectively.
[0031] The biosensor based on line tunneling dual-source L-type tunneling field-effect transistor proposed in the present invention is prepared by the following method. It should be noted that the deposition processes involved in this preparation method (steps 1, 2, 4, 5, and 7) all adopt chemical vapor deposition technology. The process conditions are using chemical vapor deposition equipment, the temperature is set to 700°C, the pressure in the reaction chamber is 760mT, the reaction source gases introduced are Si3H4 and N2O, and the protective gas is He. The doping processes involved (steps 1 and 4) all adopt ion implantation technology. The process conditions are that the arsenic ion (N-type) implantation dose is 1×10 13 cm -2 , the implantation energy is 40keV; the boron ion (P-type) implantation dose is 1×10 14 cm -2The injection energy is 10 keV. The etching processes involved (steps 3, 6, and 8) all use a dry etching process. The process conditions are to use a plasma etcher, manually set the etching chamber pressure to 10 mT, the power to 20 W, and input 50 sccm of Cl2 and 20 sccm of O2 into the etching chamber through the gas supply system.
[0032] Example 1
[0033] A biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling, wherein the substrate 8 has a length of 100 nm and a width of 20 nm; the drain region 3, the horizontal spacer 21, and the vertical spacer 22 are each 30 nm long and 20 nm wide; the horizontal source region 11 and the vertical source region 12 are each 40 nm long and 20 nm wide; the horizontal portion of the L-shaped channel 4 is 80 nm long, and the vertical portion is 70 nm long; the horizontal and vertical portions of the L-shaped oxide 5 are each 30 nm long; the horizontal portion of the L-shaped gate electrode 7 is 60 nm long, and the vertical portion is 50 nm long; and the widths of the L-shaped channel 4, the L-shaped oxide 5, and the L-shaped gate electrode 7 are each 10 nm.
[0034] A method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling specifically comprises the following steps:
[0035] Step 1: If Figure 2 As shown in Figure (a), single crystal silicon is selected as the substrate 8; germanium, silicon dioxide, and single crystal silicon are deposited on the substrate 8 from left to right to form a first germanium layer, a silicon dioxide layer, and a first silicon layer, respectively. The silicon dioxide layer is used as a horizontal spacer 21; then the first germanium layer is doped with P-type at a doping concentration of 1×10 19 cm -3 , forming a horizontal source region 11; performing N-type doping on the first silicon layer with a doping concentration of 1×10 17 cm -3 , forming the drain region 3, and entering into thermal annealing after the doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0036] Step 2: If Figure 2 As shown in (b), single crystal silicon is deposited on the horizontal source region 11, the horizontal spacer 21 and a portion of the drain region 3 to form a second silicon layer;
[0037] Step 3: If Figure 2 As shown in (c), the second silicon layer is etched to form an L-shaped channel 4;
[0038] Step 4: If Figure 2As shown in (d), silicon dioxide is deposited outside the L-shaped channel 4 to form a vertical spacer 22, and then germanium is deposited on the vertical spacer 22 to form a second germanium layer; the second germanium layer is then doped with P-type at a doping concentration of 1×10 19 cm -3 , forming a vertical source region 12, and performing thermal annealing after doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0039] Step 5: Figure 2 As shown in (e), hafnium dioxide is deposited inside the L-shaped channel 4 to form a hafnium dioxide layer;
[0040] Step 6: Figure 2 As shown in (f), the hafnium dioxide layer is etched to form an L-shaped hafnium dioxide layer;
[0041] Step 7: Figure 2 As shown in (g), metal chromium is deposited on the inner side of the L-shaped hafnium dioxide layer, that is, metal chromium is first deposited on the horizontal part and then on the vertical part to form an L-shaped gate electrode 7;
[0042] Step 8: Figure 2 As shown in (h), the L-shaped hafnium dioxide layer is partially etched to form an L-shaped oxide 5 and detection cavities located on the horizontal and vertical sides of the L-shaped oxide 5, namely, a horizontal detection cavity 61 and a vertical detection cavity 62.
[0043] Example 2
[0044] A biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling, wherein the substrate 8 has a length of 200 nm and a width of 20 nm; the drain region 3, the horizontal spacer 21, and the vertical spacer 22 are each 60 nm long and 30 nm wide; the horizontal source region 11 and the vertical source region 12 are each 80 nm long and 40 nm wide; the horizontal portion of the L-shaped channel 4 is 160 nm long, and the vertical portion is 140 nm long; the horizontal and vertical portions of the L-shaped oxide 5 are each 60 nm long; the horizontal portion of the L-shaped gate electrode 7 is 120 nm long, and the vertical portion is 100 nm long; and the widths of the L-shaped channel 4, the L-shaped oxide 5, and the L-shaped gate electrode 7 are each 20 nm.
[0045] A method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling specifically comprises the following steps:
[0046] Step 1: If Figure 2As shown in Figure (a), single crystal silicon is selected as the substrate 8; germanium, silicon dioxide, and single crystal silicon are deposited on the substrate 8 from left to right to form a first germanium layer, a silicon dioxide layer, and a first silicon layer, respectively. The silicon dioxide layer is used as a horizontal spacer 21; then the first germanium layer is doped with P-type at a doping concentration of 5×10 19 cm -3 , forming a horizontal source region 11; performing N-type doping on the first silicon layer with a doping concentration of 5×10 17 cm -3 , forming the drain region 3, and entering into thermal annealing after the doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0047] Step 2: If Figure 2 As shown in (b), single crystal silicon is deposited on the horizontal source region 11, the horizontal spacer 21 and a portion of the drain region 3 to form a second silicon layer;
[0048] Step 3: If Figure 2 As shown in (c), the second silicon layer is etched to form an L-shaped channel 4;
[0049] Step 4: If Figure 2 As shown in (d), silicon dioxide is deposited outside the L-shaped channel 4 to form a vertical spacer 22, and then germanium is deposited on the vertical spacer 22 to form a second germanium layer; the second germanium layer is then doped with P-type at a doping concentration of 5×10 19 cm -3 , forming a vertical source region 12, and performing thermal annealing after doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0050] Step 5: Figure 2 As shown in (e), titanium dioxide is deposited inside the L-shaped channel 4 to form a titanium dioxide layer;
[0051] Step 6: Figure 2 As shown in (f), the titanium dioxide layer is etched to form an L-shaped titanium dioxide layer;
[0052] Step 7: Figure 2 As shown in (g), metal gold is deposited inside the L-shaped titanium dioxide layer to form an L-shaped gate electrode 7;
[0053] Step 8: Figure 2 As shown in (h), the L-shaped titanium dioxide layer is partially etched to form an L-shaped oxide 5 and detection cavities located on the horizontal and vertical sides of the L-shaped oxide 5, namely, a horizontal detection cavity 61 and a vertical detection cavity 62.
[0054] Example 3
[0055] A biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling, wherein the substrate 8 has a length of 400 nm and a width of 20 nm; the drain region 3, the horizontal spacer 21, and the vertical spacer 22 are each 120 nm long and 30 nm wide; the horizontal source region 11 and the vertical source region 12 are each 160 nm long and 30 nm wide; the horizontal portion of the L-shaped channel 4 is 320 nm long, and the vertical portion is 280 nm long; the horizontal and vertical portions of the L-shaped oxide 5 are each 120 nm long; the horizontal portion of the L-shaped gate electrode 7 is 240 nm long, and the vertical portion is 200 nm long; and the widths of the L-shaped channel 4, the L-shaped oxide 5, and the L-shaped gate electrode 7 are each 40 nm.
[0056] A method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling specifically comprises the following steps:
[0057] Step 1: If Figure 2 As shown in Figure (a), single crystal silicon is selected as the substrate 8; gallium arsenide, silicon dioxide, and single crystal silicon are deposited on the substrate 8 from left to right to form a first gallium arsenide layer, a silicon dioxide layer, and a first silicon layer, respectively. The silicon dioxide layer is used as a horizontal spacer 21; then the first gallium arsenide layer is doped with P-type at a doping concentration of 1×10 20 cm -3 , forming a horizontal source region 11; performing N-type doping on the first silicon layer with a doping concentration of 1×10 18 cm -3 , forming the drain region 3, and entering into thermal annealing after the doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0058] Step 2: If Figure 2 As shown in (b), single crystal silicon is deposited on the horizontal source region 11, the horizontal spacer 21 and a portion of the drain region 3 to form a second silicon layer;
[0059] Step 3: If Figure 2 As shown in (c), the second silicon layer is etched to form an L-shaped channel 4;
[0060] Step 4: If Figure 2 As shown in (d), silicon dioxide is deposited outside the L-shaped channel 4 to form a vertical spacer 22, and then gallium arsenide is deposited on the vertical spacer 22 to form a second gallium arsenide layer; the second gallium arsenide layer is then doped with P-type at a doping concentration of 1×10 20 cm -3 , forming a vertical source region 12, and performing thermal annealing after doping is completed; the annealing temperature is 600° C., and the time is 4 hours;
[0061] Step 5: Figure 2As shown in (e), hafnium dioxide is deposited inside the L-shaped channel 4 to form a hafnium dioxide layer;
[0062] Step 6: Figure 2 As shown in (f), the hafnium dioxide layer is etched to form an L-shaped hafnium dioxide layer;
[0063] Step 7: Figure 2 As shown in (g), metal platinum is deposited inside the L-shaped hafnium dioxide layer to form an L-shaped gate electrode 7;
[0064] Step 8: Figure 2 As shown in (h), the L-shaped hafnium dioxide layer is partially etched to form an L-shaped oxide 5 and detection cavities located on the horizontal and vertical sides of the L-shaped oxide 5, namely, a horizontal detection cavity 61 and a vertical detection cavity 62.
[0065] like Figure 3 As shown in FIG, the biosensor prepared in Example 1 was designed and simulated using computer-aided design software. Different biomolecules have different dielectric constants (K), and the dielectric constant of air is 1. When a positive gate voltage is applied, the drain current changes significantly, indicating that the biosensor prepared in the present invention can detect neutral biomolecules. When detecting biomolecules with a dielectric constant of 10, the on-state current is 5.8×10 -2 A / μm. The sensitivity is calculated based on the ratio of the on-state current when the detection cavity is filled with different biomolecules to the on-state current when the detection cavity is filled with air. The biosensor prepared by the present invention has two biodetection cavities, which improves the sensitivity of the biosensor; when detecting biomolecules with a dielectric constant of 10, the sensitivity of the present invention reaches 1.4×10 6 .
Claims
1. A biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling, characterized in that: The invention comprises a substrate (8), a drain region (3), a vertical spacer (22), and a vertical source region (12) stacked from bottom to top; a horizontal spacer (21) and a horizontal source region (11) located on the top of the substrate (8) are sequentially arranged on the vertical side of the drain region (3); the horizontal source region (11) and the vertical source region (12) form a dual-source structure perpendicular to each other; an L-shaped channel (4), an L-shaped oxide (5), and an L-shaped gate electrode (7) are stacked from bottom to top inside the dual-source structure, and the L-shaped channel (4), the L-shaped oxide (5), and the L-shaped gate electrode (7) form two detection cavities, namely a horizontal detection cavity (61) and a vertical detection cavity (62), which are respectively located on the horizontal side and the vertical side of the L-shaped oxide (5).
2. The biosensor based on a dual-source L-type tunneling field-effect transistor of line tunneling according to claim 1, characterized in that: The horizontal source region (11) and the vertical source region (12) have exactly the same size and are perpendicular to each other, and the horizontal spacer (21) and the vertical spacer (22) have exactly the same size and are perpendicular to each other; the drain region (3) has an aspect ratio of (3-8):2 and is exactly the same size as the horizontal spacer (21) and the vertical spacer (22); the horizontal source region (11) and the drain region (3) have the same width, and their length ratio is 4:3; the horizontal portion and the vertical portion of the L-shaped channel (4) have a length ratio of 8:7:3 to the drain region (3); the horizontal portion and the vertical portion of the L-shaped oxide (5) have a length exactly the same as the drain region (3); the horizontal portion and the vertical portion of the L-shaped gate electrode (7) have a length ratio of 6:5:3 to the drain region (3); the widths of the L-shaped channel (4), the L-shaped oxide (5) and the L-shaped gate electrode (7) are all the same, and their length ratio to the drain region (3) is 1:
3.
3. A biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling according to claim 1 or 2, characterized in that: The length of the substrate (8) is the sum of the lengths of the horizontal source region (11), the horizontal spacer (21) and the drain region (3), with a width of 20 nm and a length of 200-400 nm.
4. The biosensor based on a dual-source L-type tunneling field-effect transistor of claim 1, characterized in that: The materials of the horizontal source region (11) and the vertical source region (12) are both germanium or gallium arsenide; the materials of the horizontal spacer (21) and the vertical spacer (22) are both silicon dioxide; the materials of the drain region (3), the channel (4) and the substrate (8) are all single crystal silicon; and the material of the L-type oxide (5) is hafnium dioxide or titanium dioxide.
5. The biosensor based on line tunneling dual-source L-type tunneling field effect transistor according to claim 1, characterized in that: The horizontal source region (11) and the vertical source region (12) are doped with P-type doping, with a concentration of 1×10 19 cm -3 -1×10 20 cm -3 .
6. The biosensor based on line tunneling dual-source L-type tunneling field effect transistor according to claim 1, characterized in that: The doping type of the drain region (3) is N-type doping, with a concentration of 1×10 17 cm -3 -1×10 18 cm -3 .
7. The biosensor based on line tunneling dual-source L-type tunneling field effect transistor according to claim 1, characterized in that: The work function of the L-shaped gate electrode (7) is 4.6eV-5.65eV.
8. A method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling, characterized in that: The steps are as follows: Step 1: Selecting a single crystal silicon as a substrate (8), depositing germanium or gallium arsenide, silicon dioxide, and single crystal silicon on the substrate (8) from left to right, respectively, to form a first germanium layer or a first gallium arsenide layer, a silicon dioxide layer, and a first silicon layer, and using the silicon dioxide layer as a horizontal spacer (21); then performing P-type doping on the first germanium layer or the first gallium arsenide layer to form a horizontal source region (11); performing N-type doping on the first silicon layer to form a drain region (3), and after the doping is completed, entering thermal annealing; Step 2: depositing single crystal silicon on the horizontal source region (11), the horizontal spacer (21) and part of the drain region (3) to form a second silicon layer; etching the second silicon layer to form an L-shaped channel (4); Step 3: depositing silicon dioxide outside the L-shaped channel (4) to form a vertical spacer (22), then depositing germanium or gallium arsenide on the vertical spacer (22) to form a second germanium layer or a second gallium arsenide layer; then performing P-type doping on the second germanium layer or the second gallium arsenide layer to form a vertical source region (12), and performing thermal annealing after the doping is completed; Step 4: depositing hafnium dioxide or titanium dioxide inside the L-shaped channel (4) to form a hafnium dioxide layer or a titanium dioxide layer; etching the hafnium dioxide layer or the titanium dioxide layer to form an L-shaped hafnium dioxide layer or a titanium dioxide layer; Step 5: depositing a metal on the inner side of the L-shaped hafnium dioxide layer or titanium dioxide layer to form an L-shaped gate electrode (7); the metal is chromium, gold or platinum; Step 6: Partially etching the L-shaped hafnium dioxide layer or titanium dioxide layer to form an L-shaped oxide (5) and detection cavities located on the horizontal and vertical sides of the L-shaped oxide (5), namely, a horizontal detection cavity (61) and a vertical detection cavity (62).
9. The method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling according to claim 8, characterized in that: The concentration of the N-type doping is 1× 10 17 cm -3 -1×10 18 cm -3 ; The concentration of P-type doping is 1×10 19 cm -3 -1×10 20 cm -3 .
10. The method for preparing a biosensor based on a dual-source L-type tunneling field-effect transistor with line tunneling according to claim 8, characterized in that: The deposition process adopts a chemical vapor deposition process; the doping process adopts an ion implantation process; and the etching process adopts a dry etching process.