A biosensor having a brim-like vertical tunneling field effect transistor and a method of manufacturing the same

Abstract

A biosensor with a hat-shaped vertical tunneling field effect transistor and a preparation method thereof, the sensor comprising a substrate, a drain contact arranged at both ends of the upper surface of the substrate, a drain region arranged on the upper surface of the substrate between the drain contacts, a T-shaped channel arranged on the upper surface of the drain region, a high dielectric constant oxide layer arranged on both sides of the bottom end of the vertical region of the channel, a gate metal arranged on the side of each high dielectric constant oxide layer away from the channel to form a bent biomolecule detection cavity, the channel being embedded in a source region in a horizontal region, the source region forming an outer brim and the channel forming an inner brim to form a hat-shaped structure, and a source contact arranged on the upper surface of the source region; the drain region, the channel and the source region are gradually grown on the substrate by epitaxial growth, then the biomolecule detection cavity and the high dielectric constant oxide layer are formed by atomic layer deposition and etching, and finally the gate, the source contact and the drain contact are deposited; the biosensor has the advantages of high conduction current, high sensitivity in detecting biomolecules, low voltage requirement, low power consumption and simple preparation process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor devices, and particularly relates to a biosensor with a hat-shaped vertical tunneling field effect transistor and a preparation method thereof. BACKGROUND

[0002] Biosensors can detect, record and quantify physiological parameters and biochemical processes in the body, and have a significant impact on disease diagnosis and health condition assessment. Label-free biosensors using dielectric-modulated field effect transistors are of great interest due to their fast response time, low power consumption and size compatibility with complementary metal-oxide-semiconductor technology, which solves the complexity and high manufacturing cost associated with labeled detection methods such as fluorescent labeling and radioisotopes. In DMFETs, a cavity is usually etched within the gate metal or oxide region. When biomolecules with different intrinsic properties enter the cavity, changes in electrical properties can be observed, thereby affecting the effective degree of channel-gate coupling. This dielectric modulation-based technology is also very suitable for detecting charged biomolecules.

[0003] However, as the device scale moves into the nanometer realm, MOSFET-based biosensors face increasingly serious short channel effects (SCEs). In particular, power consumption increases significantly, which does not meet the current requirement for integrated circuits to develop towards low power consumption. In addition, due to the thermal injection mechanism of carriers, the sub-threshold swing (SS) of MOSFET-based biosensors does not exceed 60 mV / dec, which also leads to slower device opening speed.

[0004] The working principle of tunnel field effect transistor (TFET) is the quantum mechanical principle of tunneling effect. It allows for lower sub-threshold swing and can achieve below 60 mV / dec at room temperature by reducing the thickness of the oxide and silicon layer. At the same time, the determining factor affecting the TFET biosensor is not the filling amount of biomolecules, the length of its detector can be less than half of the gate length, and it is also compatible with CMOS technology, which is convenient for manufacturing and integration. In recent years, researchers have shown great interest in dielectric-modulated tunnel effect transistor (DM-TFET) biosensors.

[0005] Chinese patent application No. CN112736142A discloses a biosensor based on nanosheet stacked field effect transistor and a preparation method. Three vertically stacked nanosheets constitute a channel, and a nanocavity is etched on the side close to the source end. This structure overcomes the short channel effect, but has the disadvantage of low sensitivity.

[0006] AadilAnam et al. published the Design and Performance Analysis of Tunnel Field Effect Transistor with Buried Strained Si 1-x Ge x Source Structure BasedBiosensorfor Sensitivity Enhancement(AadilAnam.Design andPerformance Analysis ofTunnel Field Effect TransistorWithBuried Strained Si 1-x Ge x Source StructureBased Biosensor for Sensitivity Enhancement[J]. IEEE SENSORS JOURNAL, 2020, 20(22): 13178–13185. ), Introducing germanium-silicon buried source regions into the channel region increases the fabrication difficulty of this structure, and also increases the power consumption of the device due to the higher operating gate voltage.

[0007] Shruti Shreya et al. disclosed a biosensor with a core-shell junctionless nanotube tunneling field-effect transistor structure (Core-Shell Junctionless Nanotube Tunnel Field Effect Transistor: Design and Sensitivity Analysis for Biosensing Application [J]. IEEE SENSORS JOURNAL, 2020, 20(2): 672–679). This biosensor uses plasma technology to induce regions with different carrier concentrations on the semiconductor surface to form source and drain regions. However, because its principle is based on charge plasma technology, the device suffers from low conduction current and low sensitivity when detecting biomolecules. Summary of the Invention

[0008] In order to overcome the above-mentioned defects of the prior art, the present application aims to provide a biosensor with a brim-shaped vertical tunneling field effect transistor and a preparation method thereof, by introducing a brim buried structure, the channel is buried in the source region or the source region is buried in the channel to increase the area of the tunneling junction, greatly improving the probability of tunneling of the source region carriers, which improves the device current and the sensitivity of detecting biomolecules, and the sensor can work under a low drain-source voltage, effectively reducing the power consumption of the device.

[0009] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0010] A biosensor with a brim-shaped vertical tunneling field effect transistor, the biosensor comprising a substrate 8, mirror image arranged with a drain contact 7 at both ends of the upper surface of the substrate 8, a drain region 6 arranged on the upper surface of the substrate 8 between the two drain contacts 7, a T-shaped channel 2 arranged on the upper surface of the drain region 6, a high dielectric constant oxide layer 4 mirror image arranged at both sides of the bottom end of the vertical region of the channel 2, a gate metal 5 arranged on the side of each high dielectric constant oxide layer 4 away from the channel 2, a bent biomolecule detection cavity 3 formed between the gate metal 5, the high dielectric constant oxide layer 4 and the channel 2, the channel 2 embedded in the source region 1 in the horizontal region, the source region 1 as the outer brim and the channel 2 as the inner brim forming a brim-shaped structure, and a source contact 9 arranged on the upper surface of the source region 1.

[0011] The source region 1 can also be embedded in the horizontal region of the channel 2, and the channel 2 as the outer brim and the source region 1 as the inner brim form a brim-shaped structure.

[0012] The source region 1 is a P-type heavily doped region, using GaSb material, with a doping concentration of 5×10 18 cm -3 ~1×10 20 cm -3 ;

[0013] The channel 2 is an N-type lightly doped region, using Si material; the carrier concentration is 1×10 15 cm -3 ~1×10 17 cm -3 ;

[0014] The drain region 6 and the substrate 8 are both N-type heavily doped regions, with a doping concentration of 1×10 18 cm -3 ~5×10 19 cm -3 ;

[0015] The high dielectric constant oxide layer 4 is HfO2 or Al2O3;

[0016] The gate metal 5 is chromium or hafnium;

[0017] The source region contact 9 and the drain region contact 7 are both polysilicon.

[0018] The biosensor is arranged in an axisymmetric manner, wherein the source region 1 is inlaid in the horizontal region of the channel 2, the length of the source region 1 is 40-80 nm, and the width is 20-40 nm; the length of the horizontal part of the channel 2 is 10-16 nm less than the length of the source region 1, the bottom of the horizontal part of the channel 2 is level with the bottom of the source region 1, and the width is 10-15 nm; the length of the vertical part of the channel 2 is 10-15 nm, and the width is 10-15 nm.

[0019] The source region 1 is inlaid in the horizontal region of the channel 2, the length of the horizontal part of the channel 2 is 40-80 nm, the width is 20-40 nm, the length of the vertical part of the channel 2 is 10-15 nm, and the width is 10-15 nm; the bottom of the source region 1 is 5-8 nm away from the bottom of the horizontal part of the channel 2, and the length of the source region 1 is 10-16 nm less than the length of the horizontal part of the channel 2;

[0020] The length of the drain region 6 is the same as the length of the vertical part of the channel 2, and the width is 10-20 nm;

[0021] The length of the substrate 8 is 40-80 nm, and the width is 20-40 nm;

[0022] The length of the horizontal part of the biomolecule detection cavity 3 is equal to the length of the horizontal part of the channel 2 plus the length of the vertical part of the channel 2, the width of the horizontal part of the biomolecule detection cavity 3 is 3-5 nm; the vertical part of the biomolecule detection cavity 3 has the same size as the high dielectric constant oxide layer 4, the length of the vertical part of the biomolecule detection cavity 3 and the high dielectric constant oxide layer 4 is the same as the width of the horizontal part of the biomolecule detection cavity 3, and the width of the vertical part of the biomolecule detection cavity 3 plus the width of the high dielectric constant oxide layer 4 is equal to the width of the vertical part of the channel 2;

[0023] The bottom of the high dielectric constant oxide layer 4 is level with the bottom of the vertical part of the channel 2;

[0024] The bottom of the gate metal 5 is level with the bottom of the high dielectric constant oxide layer 4, and the side surface is level with the side surface of the biomolecule detection cavity 3;

[0025] Each drain region contact 7 is arranged at the edge of the substrate 8, the length is 8-10 nm, and the width is 2-3 nm;

[0026] The length of the source region contact 9 is the same as the length of the source region 1, and the width is 2-3 nm.

[0027] A method for manufacturing a biosensor with a vertical tunneling field effect transistor with a brim-like cap, comprising the following steps:

[0028] Step 1: preparing a substrate 8 with a heavily doped N-type semiconductor;

[0029] Step 2: depositing a layer of polycrystalline material on the substrate 8 prepared in Step 1;

[0030] Step 3: etching the polycrystalline material deposited in Step 2 in the middle to form drain contact 7 at both ends of the substrate 8, and growing a semiconductor with the same doping concentration and type as the substrate 8 in the central region of the substrate 8 as drain 6;

[0031] Step 4: depositing a layer of metal on the drain 6 grown in Step 3;

[0032] Step 5: etching the metal deposited in Step 4 in the middle to retain the metal at both ends as gate metal 5, and depositing a layer of dielectric material with high dielectric constant in the central region;

[0033] Step 6: etching the dielectric material deposited in Step 5 to form a biomolecule detection cavity 3 and a high dielectric constant oxide layer 4;

[0034] Step 7: when the horizontal region of the channel 2 is embedded in the source 1, a T-shaped lightly doped N-type semiconductor is grown in the region etched in Step 6 as the channel 2;

[0035] When the source 1 is embedded in the horizontal region of the channel 2, a T-shaped lightly doped N-type semiconductor is grown in the region etched in Step 6;

[0036] Step 8: when the horizontal region of the channel 2 is embedded in the source 1, a layer of heavily doped P-type semiconductor is grown around the horizontal part of the T-shaped channel 2 grown in Step 7 as the source 1, and a layer of polycrystalline material is deposited on the source 1 as source contact 9;

[0037] When the source 1 is embedded in the horizontal region of the channel 2, the central region of the horizontal part of the T-shaped N-type semiconductor grown in Step 7 is etched to form the channel 2, and then a layer of heavily doped P-type semiconductor is grown in the etched region as the source 1, and a layer of polycrystalline material is deposited on the source 1 as the source contact 9.

[0038] The heavily doped N-type semiconductor in Step 1 is prepared by ion implantation process, the heavily doped N-type semiconductor is silicon, phosphorus (P) is selected as the dopant, and the doping concentration is 1×10 18 cm -3 ~ 5×10 19 cm -3, the control of the implantation energy is 50keV~200keV, the whole ion implantation process is kept at 20℃~25℃, after the ion implantation, heat annealing treatment is carried out to activate the phosphorus ions, the heat annealing temperature is at 600℃~1000℃, the heat annealing time is controlled at 30 minutes~60 minutes;

[0039] The step 2 of depositing the polycrystalline material is by using chemical vapor deposition (CVD) process, first preheat the CVD reaction chamber to 500℃~700℃, and control the chamber pressure at 10 -2 Torr~10 1 Torr to facilitate subsequent deposition, introduce dimethylsilane (SiH2(CH3)2) as silicon source gas, the flow rate is set at 50sccm~100sccm, hydrogen (H2) as diluent gas, the flow rate is set at 200sccm~500sccm, in the reaction chamber, through chemical reaction, the silicon source gas is decomposed and deposited on the substrate surface to form electrode thin film, then the deposited electrode thin film is subjected to heat annealing treatment, the heat annealing temperature is at 500℃~1000℃, the heat annealing time is controlled at 20 minutes~40 minutes;

[0040] The step 3 of etching uses dry etching technology, using high frequency inductively coupled plasma reactor (ICP-RIE), select chlorine (Cl2) as etching gas, RF power is set at 100W~300W, frequency is 13.56MHz, the etching chamber pressure is 10mTorr~50mTorr, etching is carried out at 25℃~30℃, the etching rate is 30nm / min~50nm / min, the same doped concentration and type of semiconductor as the substrate 8 is generated by epitaxial growth process, using silicon material, first clean the silicon substrate for epitaxial growth, then place the cleaned silicon substrate in the epitaxial growth chamber for subsequent operation, the epitaxial growth chamber is in vacuum or inert gas environment, set the growth temperature at 1100℃~1300℃, the pressure is at 90Pa~100Pa low pressure environment, the flow rate of silicon source gas is set at 15sccm~20sccm, the flow rate of hydrogen as carrier gas is set at 180sccm~200sccm, in the growth process, introduce phosphine (PH3) as dopant gas, the doping concentration is 1×10 18 cm -3 ~5×10 19 cm -3 , the growth time is set at 30 minutes~120 minutes, after the growth, heat annealing treatment is carried out, the heat annealing temperature is at 400℃~800℃, the heat annealing time is controlled at 10 minutes~30 minutes;

[0041] The step 4 of depositing metal is using a reactive sputtering process, the deposited metal is metal chromium or metal hafnium, the reactive sputtering process is using a magnetron sputtering system to deposit, first heating the target material to 200-400℃ to increase the evaporation rate of the metal, while controlling the temperature of the substrate at 100-300℃ to avoid thermal damage to the thin film on the substrate, the pressure of the sputtering chamber is set at 10 -6 Torr-10 -8 Torr, start the sputtering system, heat the target material of the deposited metal and apply an electric field, so that the target material is sputtered from the surface of the target gun to the silicon substrate, set the sputtering power at 100-200W to form the required metal thin film on the semiconductor surface, after the sputtering process is completed, release the vacuum chamber gas and take out the semiconductor substrate, and use characterization techniques to evaluate the morphology, composition and bonding state of the metal thin film, including SEM, XPS, to ensure the quality and stability of the gate electrode;

[0042] The step 5 of etching metal is a metal gate etching process, a mixture of Cl2 and Br2 gas is selected, the gas volume ratio is (1-3):1, the RF power is set at 200-300W, the frequency is 13.56MHz, the pressure in the etching chamber is 20-40mTorr, and the etching rate is 50-70nm / min, the deposition of dielectric material is an atomic layer deposition process (ALD), the deposited dielectric material is HfO2 or Al2O3, the bottom of the dielectric material is flat with the bottom of the metal gate 5, the width is the sum of the width of the metal gate 5 and the length of the high dielectric constant oxide layer 4, the atomic layer deposition process (ALD) first performs chemical cleaning or hydrogen treatment on the semiconductor material to remove oxides and organic residues and ensure optimal surface acceptance, trimethylhafnium or trimethylaluminum is used as the precursor of the deposited dielectric layer, the precursor is introduced into the reaction chamber, the precursor is adsorbed on the silicon surface, oxygen or nitrogen is introduced to remove unreacted precursors and byproducts, water vapor is introduced as an oxidizing agent to react with the adsorbed precursor to form a dielectric layer thin film, the purification step is repeated to remove byproducts and unreacted gas generated during the reaction, during this process, the temperature is controlled at 200-400℃ and adjusted according to the characteristics of the ALD precursor and the reaction conditions, the environmental pressure is maintained at 2-10Torr, the thickness of the dielectric layer thin film is increased by repeating the ALD cycle, each cycle increases the thickness by 5-20 angstroms;

[0043] The step 6 uses dry etching, selects inductively coupled plasma (ICP) etching machine and hydrogen fluoride (HF) as etching gas to operate, the overall environmental temperature needs to be kept at 20-25℃, starts the inductively coupled plasma (ICP) etching machine, generates plasma, then inputs hydrogen fluoride (HF) etching gas, ensures that the flow is 40-50sccm, adjusts the reaction chamber pressure to 40-50mTorr to maintain stable etching atmosphere, under the discharge power of 100-300W and the frequency of 13.56MHz, hydrogen fluoride (HF) reacts with the surface of the dielectric layer to generate fluoride, so as to realize etching, and after etching, cleaning is carried out to remove etching residues;

[0044] The step 7 uses epitaxial growth technology to form a lightly doped N-type semiconductor, the lightly doped N-type semiconductor is silicon, first, the device is cleaned, then the cleaned silicon substrate is placed in the epitaxial growth chamber for subsequent operation, the epitaxial growth chamber is a vacuum or inert gas environment, the growth temperature is set at 1100-1300℃, the pressure is set at 90-100Pa low pressure environment, the flow rate of silicon source gas is set at 15-20sccm, and the flow rate of hydrogen as carrier gas is set at 180-200sccm, in the growth process, phosphine (PH3) is introduced as a dopant gas, the doping concentration is 1×10 15 cm -3 ~1×10 17 cm -3 , the growth time is set at 30-120 minutes, after growth, the epitaxial layer is subjected to heat annealing treatment to optimize the crystal structure and electrical properties; the heat annealing temperature is 600-900℃, and the heat annealing time is controlled at 20-40 minutes;

[0045] The step 8, when the horizontal region of the channel 2 is embedded in the source region 1, forms a heavily doped P-type semiconductor, gallium antimonide (GaSb), by using molecular beam epitaxy (MBE) technology, when the source region 1 is embedded in the horizontal region of the channel 2, dry etching is used, using a high-frequency inductively coupled plasma reactor (ICP-RIE), selecting chlorine (Cl2) as the etching gas, setting the RF power to 100W-200W, the frequency to 13.56MHz, the pressure in the etching chamber to 20mTorr-30mTorr, and etching at 25℃-30℃, with an etching rate of 30nm / min-50nm / min, and then forming a heavily doped P-type semiconductor, gallium antimonide (GaSb), by using molecular beam epitaxy (MBE) technology. First, the silicon substrate for epitaxial growth is cleaned, and then the cleaned silicon substrate is placed in the MOCVD reaction chamber for subsequent operation, setting the reaction temperature to 500℃-700℃, using trimethyl gallium (TMGa) and arsine (AsH3) as the reaction gas, with a gas volume ratio of 1:(8-12), adding dimethyl germanium (GeH2) or dimethyl zinc (Zn(CH3)2) as a dopant during growth, with a doping concentration of 5×10 18 cm -3 -1×10 20 cm -3 , after growth, heat annealing is performed at a temperature of 300℃-500℃ for 30-50 minutes, polycrystalline material is deposited using chemical vapor deposition (CVD) technology, the polycrystalline material is polysilicon, the CVD reaction chamber is first preheated to 500℃-700℃, and the pressure in the chamber is controlled to 10 -2 Torr-10 1 Torr to facilitate subsequent deposition, dimethylsilane (SiH2(CH3)2) is introduced as the silicon source gas, with a flow rate of 50sccm-100sccm, and hydrogen (H2) is used as the diluent gas, with a flow rate of 200sccm-500sccm, the silicon source gas is decomposed in the reaction chamber and deposited on the substrate surface to form an electrode thin film, and then the deposited electrode thin film is annealed to improve its crystallinity and electrical properties, with a heat annealing temperature of 500℃-1000℃ and a heat annealing time of 20-40 minutes.

[0046] The length of the heavily doped N-type semiconductor in step 1 is 40-80nm, and the width is 20-40nm.

[0047] The length of the polycrystalline material in step 2 is consistent with the length of the substrate 8, and the width is 2-3nm.

[0048] The contact 7 of the step 3 is arranged at the edge of the substrate 8, with a length of 8-10 nm, and a length of 10-15 nm and a width of 10-20 nm of the semiconductor with the same doping concentration and type as the substrate 8;

[0049] The deposited metal of the step 4 has a length of 30-35 nm and a width of 7-10 nm;

[0050] The length of the etched region of the step 5 is the length of the drain region 6 plus the length of the high dielectric constant oxide layer 4 on both sides, which is 3-5 nm;

[0051] The vertical part of the biomolecule detection cavity 3 formed in the step 6 has the same size as the high dielectric constant oxide layer 4, and the length of the horizontal part of the biomolecule detection cavity 3 on both sides plus the length of the vertical part of the channel 2 is equal to the length of the horizontal part of the channel 2, the width of the horizontal part of the biomolecule detection cavity 3 is 3-5 nm, the vertical part of the biomolecule detection cavity 3 is arranged above the high dielectric constant oxide layer 4, with a length equal to the width of the horizontal part and a width equal to the width of the high dielectric constant oxide layer 4 plus the width of the vertical part of the channel 2, the bottom of the high dielectric constant oxide layer 4 is flush with the bottom of the vertical part of the channel 2, and the length of the high dielectric constant oxide layer 4 is consistent with the length of the vertical part of the biomolecule detection cavity 3;

[0052] When the horizontal region of the channel 2 is embedded in the source region 1 in the step 7, the length of the vertical part of the channel 2 is 10-15 nm and the width is 10-15 nm, and the length of the horizontal part of the channel 2 is the same as the length of the drain region 6 and the length of the horizontal part of the biomolecule detection cavity 3 on both sides;

[0053] When the source region 1 is embedded in the horizontal region of the channel 2, the width of the horizontal part of the T-shaped lightly doped N-type semiconductor is 20-40 nm and the length is 40-80 nm, and the length of the vertical part of the T-shaped lightly doped N-type semiconductor is 10-15 nm and the width is 10-15 nm;

[0054] When the horizontal region of the channel 2 is embedded in the source region 1 in the step 8, the length of the source region 1 is 40-80 nm and the width is 20-40 nm, and the distance between the left and right sides of the source region 1 and the left and right sides of the horizontal part of the channel 2 is the same, which is 5-8 nm, the length of the source contact 9 is consistent with the length of the source region 1, and the width is 2-3 nm;

[0055] When the source region 1 is embedded in the horizontal region of the channel 2, the bottom of the source region 1 is 5-8 nm above the bottom of the horizontal part of the channel 2, and the two sides of the source region 1 are inside the two sides of the horizontal part of the channel 2, and the distance between the two sides is 5-10 nm; the material of the source region contact 9 is polysilicon, the length is consistent with the length of the source region 1, and the width is 2-3 nm.

[0056] Compared with the prior art, the present application has the beneficial effects that:

[0057] 1. The present application adopts a brim structure at the tunnel junction to increase the tunneling area of the carriers, and due to the embedding of the inner brim channel 2, the carriers of the source region 1 not only undergo lateral tunneling, but also undergo vertical tunneling. When the voltage of the gate metal 5 gradually increases, the brim-shaped structure causes the device to have a mutation point at a certain gate voltage, and the value of the on-current increases sharply. Compared with the recently published TFET biosensor device, the present application effectively solves the defect of insufficient on-current of the TFET.

[0058] 2. The biosensor cavity 3 of the present application adopts a bending structure, which increases the effective coupling degree between the gate metal 5 and the channel 2. The cavity arranged in the horizontal direction not only effectively affects the lateral tunneling of the outer brim, but also affects the vertical tunneling of the outer brim. Based on the structure of the biosensor, the electrical characteristics before and after the coupling of the biomolecules can be greatly changed, and excellent sensitivity performance is exhibited.

[0059] 3. The brim structure of the present application increases the probability of band-to-band tunneling of the source region carriers, effectively suppresses the barrier width at the tunnel junction, and enables the biosensor to exhibit excellent electrical characteristics at a lower voltage, which can be used in the field of low power consumption.

[0060] 4. The structure of the present application, in which the source region is embedded in the channel, increases the modulation effect of the biomolecules in the cavity region on the energy band at the tunnel junction, and increases the detection capability of the biosensor before and after the coupling of the biomolecules.

[0061] 5. The present application forms the drain region contact 7 on the N-type heavily doped substrate 8 by using chemical vapor deposition and dry etching technology, forms the biomolecule detection cavity 3 and high dielectric constant oxide layer 4 by using atomic layer deposition process and dry etching technology, then grows the drain region 6, channel 2 and source region 1 by using epitaxial growth process, forms the gate metal 5 on the surface of the biomolecule detection cavity 3 and high dielectric constant oxide layer 4 by using reactive sputtering process, and forms the polysilicon contact on the surface of the substrate 8 and the source region 1 by chemical vapor deposition. Compared with the existing germanium-silicon buried source region biosensor in the background art, the preparation process of such a complex structure is simpler, and the process cost is reduced.

[0062] In conclusion, the application has the advantages of high on-current, high sensitivity of biomolecule detection, low working voltage, low power consumption and simple preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The structure diagram of the application, in which the channel 2 is embedded in the source region 1.

[0064] Figure 2 The structure diagram of the application, in which the source region 1 is embedded in the channel 2.

[0065] Figure 3 The preparation flow chart of the structure of the application, in which the channel 2 is embedded in the source region 1.

[0066] Figure 4 The preparation flow chart of the structure of the application, in which the source region 1 is embedded in the channel 2.

[0067] Figure 5 The simulation transfer characteristic curve diagram of the application, in which the channel 2 is embedded in the source region 1.

[0068] Figure 6 The on-current sensitivity comparison diagram of the application, in which the channel 2 is embedded in the source region 1 and the traditional VTFET biosensor in different dielectric constant biomolecules.

[0069] Figure 7 The simulation transfer characteristic curve diagram of the application, in which the source region 1 is embedded in the channel 2.

[0070] Figure 8 The on-current sensitivity comparison diagram of the application, in which the source region 1 is embedded in the channel 2 and the traditional VTFET biosensor in different dielectric constant biomolecules.

[0071] In the figure, 1 is the source region; 2 is the channel; 3 is the biomolecule detection cavity; 4 is the high dielectric constant oxide layer; 5 is the gate metal; 6 is the drain region; 7 is the drain region contact; 8 is the substrate; 9 is the source region contact. DETAILED DESCRIPTION

[0072] The application will be described in detail below with reference to the accompanying drawings.

[0073] Example 1

[0074] Reference Figure 1The utility model provides a kind of biosensor with brim-shaped vertical tunneling field effect transistor, the biosensor includes substrate 8, mirror image is provided with drain region contact 7 on the upper surface of substrate 8 both ends, the upper surface of substrate 8 between two drain region contacts 7 is provided with drain region 6, the upper surface of drain region 6 is provided with T-shaped channel 2, mirror image is provided with high dielectric constant oxide layer 4 on both sides of the bottom end of vertical area of channel 2, each high dielectric constant oxide layer 4 is provided with gate metal 5 away from one side of channel 2, gate metal 5, high dielectric constant oxide layer 4 and channel 2 are enclosed and form the bent biological molecule detection cavity 3 between, channel 2 is embedded in source region 1 in horizontal area, source region 1 is outer eave, channel 2 is inner eave and forms brim-shaped structure, source region 1 upper surface is provided with source region contact 9;

[0075] The source region 1 is P-type heavily doped region, adopts GaSb material, and the doping concentration is 5×10 18 cm -3 ;

[0076] Channel 2 is N-type lightly doped region, adopts Si material;Carrier concentration is 1×10 15 cm -3 ;

[0077] Drain region 6 and substrate 8 are N-type heavily doped region, and the doping concentration is 1×10 18 cm -3 ;

[0078] High dielectric constant oxide layer 4 is HfO2;

[0079] Gate metal 5 is chromium;

[0080] Source region contact 9 and drain region contact 7 are both polycrystalline silicon.

[0081] The biosensor is axisymmetric, wherein the length of the source region 1 is 40 nm, and the width is 20 nm;The length of the horizontal part of the channel 2 is 10 nm less than the length of the source region 1, and the bottom is level with the bottom of the source region 1, and the width is 10 nm;The length of the vertical part of the channel 2 is 10 nm, and the width is 10 nm;

[0082] The length of the drain region 6 is the same as the length of the vertical part of the channel 2, and the width is 10 nm;

[0083] The length of the substrate 8 is 40 nm, and the width is 20 nm;

[0084] The length of the horizontal part of the biomolecule detection cavity 3 plus the length of the vertical part of the channel 2 equals the length of the horizontal part of the channel 2, and the width of the horizontal part of the biomolecule detection cavity 3 is 3 nm; the vertical part of the biomolecule detection cavity 3 has the same size as the high dielectric constant oxide layer 4, the length of the vertical part of the biomolecule detection cavity 3 and the high dielectric constant oxide layer 4 is the same as the width of the horizontal part of the biomolecule detection cavity 3, and the width of the vertical part of the biomolecule detection cavity 3 plus the width of the high dielectric constant oxide layer 4 equals the width of the vertical part of the channel 2;

[0085] The bottom of the high dielectric constant oxide layer 4 is level with the bottom of the vertical part of the channel 2;

[0086] The bottom of the gate metal 5 is level with the bottom of the high dielectric constant oxide layer 4, and the side is level with the side of the biomolecule detection cavity 3;

[0087] Each drain contact 7 is arranged at the edge of the substrate 8, with a length of 8 nm and a width of 2 nm;

[0088] The length of the source contact 9 is the same as the length of the source region 1, and the width is 2 nm.

[0089] Referring to Figure 3 A method for preparing a biomolecule sensor with a brim-shaped vertical tunneling field effect transistor, comprising the following steps:

[0090] Step 1: Prepare a substrate 8 with a heavily doped N-type semiconductor;

[0091] Step 2: Deposit a layer of polycrystalline material on the substrate 8 prepared in step 1;

[0092] Step 3: Etch the middle of the polycrystalline material deposited in step 2 to form drain contacts 7 at both ends of the substrate 8, and grow a semiconductor with the same doping concentration and type as the substrate 8 in the central region of the substrate 8 as a drain region 6;

[0093] Step 4: Deposit a layer of metal on the drain region 6 grown in step 3;

[0094] Step 5: Etch the middle of the metal deposited in step 4 to retain the metal at both ends as gate metal 5, and deposit a layer of dielectric material with high dielectric constant in the central region;

[0095] Step 6: Etch the dielectric material deposited in step 5 to form a biomolecule detection cavity 3 and a high dielectric constant oxide layer 4;

[0096] Step 7: Grow a T-shaped lightly doped N-type semiconductor as a channel 2 in the area etched in step 6;

[0097] Step 8: A layer of heavily doped P-type semiconductor is grown around the horizontal portion of the T-type channel 2 grown in step 7 as the source region 1, and a layer of polycrystalline material is deposited on top of the source region 1 as the source region contact 9.

[0098] The heavily doped N-type semiconductor in step 1 is produced using an ion implantation process. The heavily doped N-type semiconductor is silicon, and phosphorus (P) is selected as the dopant with a doping concentration of 1 × 10⁻⁶. 18 cm -3 The implantation energy was controlled at 50keV, and the entire ion implantation process was carried out at 20℃. After the ion implantation was completed, a thermal annealing treatment was performed to activate phosphorus ions. The thermal annealing temperature was 600℃, and the thermal annealing time was controlled at 30 minutes.

[0099] The deposition of polycrystalline material in step 2 is carried out using chemical vapor deposition (CVD) technology. First, the CVD reaction chamber is preheated to 500°C, and the pressure inside the chamber is controlled at 10. -2 Torr was used to promote subsequent deposition. Dimethylsilane (SiH2(CH3)2) was introduced as the silicon source gas with a flow rate of 50 sccm, and hydrogen (H2) was used as the diluent gas with a flow rate of 200 sccm. In the reaction chamber, the silicon source gas was decomposed by chemical reaction and an electrode film was deposited on the substrate surface. The deposited electrode film was then subjected to thermal annealing at a temperature of 500°C for 20 minutes.

[0100] Step 3 etching employs dry etching technology using a high-frequency inductively coupled plasma reactor (ICP-RIE). Chlorine (Cl2) is selected as the etching gas, with RF power set at 100W, frequency at 13.56MHz, and chamber pressure at 10mTorr. Etching is performed at 25°C at a rate of 30nm / min. Semiconductors with the same doping concentration and type as substrate 8 are generated using epitaxial growth technology with silicon as the material. First, the silicon substrate for epitaxial growth is cleaned. Then, the cleaned substrate is placed in the epitaxial growth chamber for subsequent operations. The epitaxial growth chamber is a vacuum gas environment, with the growth temperature set at 1100°C and the pressure at 90Pa. The silicon source gas flow rate is set at 15sccm, and the hydrogen carrier gas flow rate is set at 180sccm. During growth, phosphine (PH3) is introduced as a dopant gas with a doping concentration of 1×10⁻⁶. 18 cm -3 The growth time was set at 30 minutes. After growth was completed, the material was subjected to heat annealing at 400℃ for 10 minutes.

[0101] The step 4 of depositing metal is using a reactive sputtering process, the deposited metal is chromium, the reactive sputtering process is using a magnetron sputtering system to deposit, first heat the target material to 200℃ to increase the evaporation rate of the metal, while controlling the temperature of the substrate at 100℃ to avoid thermal damage to the thin film on the substrate, the pressure of the sputtering chamber is set to 10 -6 Torr, start the sputtering system, heat the target material of the deposited metal and apply an electric field, so that the target material is sputtered from the surface of the target gun to the silicon substrate, set the sputtering power to 100W to form the required metal thin film on the semiconductor surface, after the sputtering process is completed, release the vacuum chamber gas and take out the semiconductor substrate, and use characterization techniques to evaluate the morphology, composition and bonding state of the metal thin film, the characterization technique is SEM, to ensure the quality and stability of the gate electrode;

[0102] The step 5 of etching metal is a metal gate etching process, a mixture of Cl2 and Br2 gas is selected, the gas volume ratio is 1:1, the RF power is set to 200W, the frequency is 13.56MHz, the pressure in the etching chamber is 20mTorr, and the etching rate is 50nm / min, the deposition of dielectric material is an atomic layer deposition process (ALD), the deposited dielectric material is HfO2, the bottom of the dielectric material is flat with the bottom of the metal gate 5, the width is the sum of the width of the metal gate 5 and the length of the high dielectric constant oxide layer 4, the atomic layer deposition process (ALD) first performs chemical cleaning on the semiconductor material to remove oxides and organic residues, ensuring optimal surface acceptance, using hafnium trimethoxide as the precursor for depositing the dielectric layer, introducing the precursor into the reaction chamber, allowing the precursor to adsorb on the silicon surface, introducing oxygen to remove unreacted precursors and byproducts, introducing water vapor as an oxidizing agent to react with the adsorbed precursor to form a dielectric layer thin film layer, repeating the purification step to remove byproducts and unreacted gases generated during the reaction, the temperature is controlled at 200℃ during the process, and the environmental pressure is adjusted according to the characteristics of the ALD precursor and the reaction conditions, the environmental pressure is maintained at 2Torr, the thickness of the dielectric layer thin film is increased by repeating the ALD cycle, each cycle increases the thickness by 5 angstroms;

[0103] The step 6 uses dry etching, selects an inductively coupled plasma (ICP) etching machine and hydrogen fluoride (HF) as the etching gas, the overall environmental temperature needs to be maintained at 20℃, starts the inductively coupled plasma (ICP) etching machine, generates plasma, then inputs the hydrogen fluoride (HF) etching gas, ensures the flow rate is 40sccm, adjusts the reaction chamber pressure to 40mTorr to maintain a stable etching atmosphere, under a discharge power of 100W and a frequency of 13.56MHz, hydrogen fluoride (HF) reacts with the surface of the dielectric layer to form fluoride, thereby achieving etching, after etching is completed, cleaning is performed to remove etching residues;

[0104] The step 7 uses epitaxial growth technology to form a lightly doped N-type semiconductor, which is silicon. The device is first cleaned and then the cleaned silicon substrate is placed in an epitaxial growth chamber for subsequent operation. The epitaxial growth chamber is a vacuum or inert gas environment. The growth temperature is set at 1100°C. The pressure is set at a low pressure of 90 Pa. The flow rate of the silicon source gas is set at 15 sccm. Hydrogen is used as the carrier gas, and the flow rate is set at 180 sccm. During the growth process, phosphine (PH3) is introduced as a dopant gas, and the doping concentration is 1×10 15 cm -3 The growth time is set at 30 minutes. After the growth is completed, the epitaxial layer is subjected to a thermal annealing process to optimize the crystal structure and electrical properties. The thermal annealing temperature is 600°C, and the thermal annealing time is controlled at 20 minutes.

[0105] The step 8 uses molecular beam epitaxy (MBE) technology to form a heavily doped P-type semiconductor, which is gallium antimonide (GaSb). Subsequently, molecular beam epitaxy (MBE) technology is used to form a heavily doped P-type semiconductor, which is gallium antimonide (GaSb). The silicon substrate for epitaxial growth is first cleaned, and then the cleaned silicon substrate is placed in an MOCVD reaction chamber for subsequent operation. The reaction temperature is set at 500°C. Trimethylgallium (TMGa) and arsine (AsH3) are used as reaction gases, and the gas volume ratio is 1:8. Dimethyl germanium (GeH2) is added as a dopant during the growth process, and the doping concentration is 5×10 18 cm -3 After the growth is completed, a thermal annealing process is performed. The thermal annealing temperature is 300°C, and the time is 30 minutes. The polycrystalline material is deposited using chemical vapor deposition (CVD) technology. The polycrystalline material is polycrystalline silicon. The CVD reaction chamber is first preheated to 500°C, and the chamber pressure is controlled at 10 -2 Torr to facilitate subsequent deposition. Dimethylsilane (SiH2(CH3)2) is introduced as the silicon source gas, and the flow rate is set at 50 sccm. Hydrogen (H2) is used as the diluent gas, and the flow rate is set at 200 sccm. The silicon source gas is decomposed in the reaction chamber and deposited on the substrate surface to form an electrode thin film. Subsequently, the deposited electrode thin film is subjected to an annealing process to improve its crystallinity and electrical properties. The thermal annealing temperature is 500°C, and the thermal annealing time is controlled at 20 minutes.

[0106] The heavily doped N-type semiconductor in step 1 has a length of 40 nm and a width of 20 nm.

[0107] The polycrystalline material in step 2 has a length consistent with the length of the substrate 8 and a width of 2 nm.

[0108] The step 3 contact 7 is set on the edge of the substrate 8, with a length of 8 nm, a semiconductor length of 10 nm and a width of 10 nm, which is the same doping concentration and type as the substrate 8;

[0109] The step 4 deposits a metal with a length of 30 nm and a width of 7 nm;

[0110] The step 5 etches a region with a length equal to the length of the drain region 6 plus the length of the high dielectric constant oxide layer 4 on both sides, which is 3 nm;

[0111] The step 6 forms a biomolecule detection cavity 3 with the same size as the high dielectric constant oxide layer 4 in the vertical direction, and the length of the horizontal part of the biomolecule detection cavity 3 on both sides plus the length of the vertical part of the channel 2 is equal to the length of the horizontal part of the channel 2, the width of the horizontal part of the biomolecule detection cavity 3 is 3 nm, the vertical part of the biomolecule detection cavity 3 is placed above the high dielectric constant oxide layer 4, with a length equal to the width of the horizontal part, and a width equal to the width of the high dielectric constant oxide layer 4 plus the width of the vertical part of the channel 2; the bottom of the high dielectric constant oxide layer 4 is flush with the bottom of the vertical part of the channel 2, and the length is consistent with the length of the vertical part of the biomolecule detection cavity 3;

[0112] The step 7 forms a channel 2 with a vertical part length of 10 nm and a width of 10 nm; the horizontal part of the channel 2 has the same length as the length of the drain region 6 and the length of the horizontal part of the biomolecule detection cavity 3 on both sides;

[0113] The step 8 forms a source region 1 with a length of 40 nm and a width of 20 nm, and the distance between the left and right sides of the source region 1 and the horizontal part of the channel 2 is 5 nm; the source contact 9 has the same length as the source region 1 and a width of 2 nm.

[0114] Example 2

[0115] Referring to Figure 2 A biomolecule sensor with a vertical tunneling field effect transistor with a brim shape, the biomolecule sensor comprising a substrate 8, mirror image setting a drain contact 7 on both ends of the upper surface of the substrate 8, setting a drain region 6 on the upper surface of the substrate 8 between the two drain contacts 7, setting a T-shaped channel 2 on the upper surface of the drain region 6, mirror image setting a high dielectric constant oxide layer 4 on both sides of the bottom of the vertical region of the channel 2, setting a gate metal 5 on the side of each high dielectric constant oxide layer 4 away from the channel 2, forming a bent biomolecule detection cavity 3 between the gate metal 5, the high dielectric constant oxide layer 4 and the channel 2, embedding a source region 1 in the horizontal region of the channel 2, forming a brim shape structure with the channel 2 as the outer brim and the source region 1 as the inner brim, and setting a source contact 9 on the upper surface of the source region 1;

[0116] The source region 1 is a P-type heavily doped region, adopts GaSb material, and has a doping concentration of 1×10 20 cm -3 ;

[0117] The channel 2 is an N-type lightly doped region, adopts Si material, and has a carrier concentration of 1×10 17 cm -3 ;

[0118] The drain region 6 and the substrate 8 are both N-type heavily doped regions, and have a doping concentration of 5×10 19 cm -3 ;

[0119] The high dielectric constant oxide layer 4 is Al2O3;

[0120] The gate metal 5 is hafnium;

[0121] The source region contact 9 and the drain region contact 7 are both polysilicon.

[0122] The biosensor is arranged in an axisymmetric manner, wherein the length of the horizontal part of the channel 2 is 80 nm, the width of the horizontal part of the channel 2 is 40 nm, the length of the vertical part of the channel 2 is 15 nm, and the width of the vertical part of the channel 2 is 15 nm; the bottom of the source region 1 is 8 nm away from the bottom of the horizontal part of the channel 2, and the length of the source region 1 is 16 nm less than the length of the horizontal part of the channel 2;

[0123] The length of the drain region 6 is the same as the length of the vertical part of the channel 2, and the width of the drain region 6 is 20 nm;

[0124] The length of the substrate 8 is 80 nm, and the width of the substrate 8 is 40 nm;

[0125] The length of the horizontal part of the biomolecule detection cavity 3 is equal to the length of the vertical part of the channel 2 plus the length of the horizontal part of the channel 2, and the width of the horizontal part of the biomolecule detection cavity 3 is 5 nm; the vertical part of the biomolecule detection cavity 3 has the same size as the high dielectric constant oxide layer 4, the length of the vertical part of the biomolecule detection cavity 3 and the high dielectric constant oxide layer 4 is the same as the width of the horizontal part of the biomolecule detection cavity 3, and the width of the vertical part of the biomolecule detection cavity 3 plus the width of the high dielectric constant oxide layer 4 is equal to the width of the vertical part of the channel 2;

[0126] The bottom of the high dielectric constant oxide layer 4 is level with the bottom of the vertical part of the channel 2;

[0127] The bottom of the gate metal 5 is level with the bottom of the high dielectric constant oxide layer 4, and the side surface of the gate metal 5 is level with the side surface of the biomolecule detection cavity 3;

[0128] Each drain region contact 7 is arranged at the edge of the substrate 8, has a length of 10 nm, and has a width of 3 nm;

[0129] The length of the source region contact 9 is the same as that of the source region 1, and the width is 3 nm.

[0130] Referring to Figure 4 A method for preparing a biosensor with a vertical tunneling field effect transistor with a brim shape, comprising the following steps:

[0131] Step 1: preparing a substrate 8 with a heavily doped N-type semiconductor as a substrate 8;

[0132] Step 2: depositing a layer of polycrystalline material on the substrate 8 prepared in step 1;

[0133] Step 3: etching the middle of the polycrystalline material deposited in step 2 to form drain region contacts 7 at both ends of the substrate 8, and growing a semiconductor with the same doping concentration and type as the substrate 8 in the central region of the substrate 8 as a drain region 6;

[0134] Step 4: depositing a layer of metal on the drain region 6 grown in step 3;

[0135] Step 5: etching the middle of the metal deposited in step 4 to retain the metal at both ends as gate metal 5, and depositing a layer of dielectric material with high dielectric constant in the central region;

[0136] Step 6: etching the dielectric material deposited in step 5 to form a biomolecule detection cavity 3 and a high dielectric constant oxide layer 4;

[0137] Step 7: growing a T-shaped lightly doped N-type semiconductor in the area etched in step 6;

[0138] Step 8: etching the central region of the horizontal part of the T-shaped N-type semiconductor grown in step 7 to form a channel 2, and then growing a layer of heavily doped P-type semiconductor as a source region 1 in the etched area, and depositing a layer of polycrystalline material as a source region contact 9 above the source region 1.

[0139] The heavily doped N-type semiconductor in step 1 is prepared by ion implantation process, the heavily doped N-type semiconductor is silicon, phosphorus (P) is selected as the dopant, the doping concentration is 5×10 19 cm -3 The ion implantation process is carried out at 25℃, and after the ion implantation is completed, heat treatment is carried out to activate the phosphorus ions, the heat treatment temperature is 1000℃, and the heat treatment time is controlled within 60 minutes;

[0140] The deposition of polycrystalline material in step 2 is carried out by chemical vapor deposition (CVD) process, first preheat the CVD reaction chamber to 700℃, and control the chamber pressure to 10 1Torr, to facilitate subsequent deposition, dimethylsilane (SiH2(CH3)2) is introduced as a silicon source gas, with a flow rate of 100 sccm, and hydrogen (H2) is introduced as a diluent gas, with a flow rate of 500 sccm, to decompose the silicon source gas in the reaction chamber by chemical reaction and deposit an electrode thin film on the substrate surface, and then the deposited electrode thin film is subjected to a thermal annealing process, with a thermal annealing temperature of 1000°C and a thermal annealing time of 40 minutes;

[0141] The step 3 etching uses a dry etching technique, using a high-frequency inductively coupled plasma reactor (ICP-RIE), selecting chlorine gas (Cl2) as the etching gas, setting the RF power at 300 W, the frequency at 13.56 MHz, and the etching chamber pressure at 50 mTorr, and etching at 30°C with an etching rate of 50 nm / min, to generate a semiconductor with the same doping concentration and type as the substrate 8 using an epitaxial growth process, using silicon material, first cleaning the silicon substrate for epitaxial growth, then placing the cleaned silicon substrate in the epitaxial growth chamber for subsequent operation, the epitaxial growth chamber being a vacuum or inert gas environment, setting the growth temperature at 1300°C, the pressure at 100 Pa in a low-pressure environment, the flow rate of the silicon source gas at 20 sccm, and the flow rate of hydrogen as the carrier gas at 200 sccm, introducing phosphine (PH3) as a dopant gas during growth, with a doping concentration of 5×10 19 cm -3 , and setting the growth time at 120 minutes, and after growth, performing a thermal annealing process with a thermal annealing temperature of 800°C and a thermal annealing time of 30 minutes;

[0142] The step 4 deposition of metal is performed using a reactive sputtering process, the deposited metal being hafnium, the reactive sputtering process using a magnetron sputtering system, first heating the target material to 400°C to increase the evaporation rate of the metal, while controlling the temperature of the substrate to 300°C to avoid thermal damage to the thin film on the substrate, setting the pressure in the sputtering chamber to 10 -8 Torr, starting the sputtering system, heating the target material of the deposited metal and applying an electric field to cause the target material to sputter from the surface of the target gun to the silicon substrate, setting the sputtering power to 200 W to form the desired metal thin film on the semiconductor surface, after the sputtering process is complete, releasing the vacuum chamber gas and removing the semiconductor substrate, and using characterization techniques to evaluate the morphology, composition, and bonding state of the metal thin film, the characterization technique being XPS, to ensure the quality and stability of the gate electrode;

[0143] The step 5 etching metal process is a metal gate etching process, selecting a mixed gas of Cl2 and Br2, the gas volume ratio is 3:1, set RF power 300W, frequency is 13.56MHz, the pressure in the etching chamber is 40mTorr, the etching rate is 70nm / min, the process of depositing dielectric material is atomic layer deposition process (ALD), the deposited dielectric material is Al2O3, the bottom of the dielectric material is flat with the bottom of the metal gate 5, the width is the sum of the width of the metal gate 5 and the length of the high dielectric constant oxide layer 4, the atomic layer deposition process (ALD) first carries out hydrogen treatment on the semiconductor material to remove oxides and organic residues, ensure the best surface acceptance, use trimethylaluminum as the precursor of the deposited dielectric layer, introduce the precursor into the reaction chamber, make the precursor adsorb on the silicon surface, introduce nitrogen to remove unreacted precursors and byproducts, introduce water vapor as an oxidizing agent to react with the adsorbed precursor to form a dielectric layer film, repeat the purification step to remove byproducts and unreacted gas generated during the reaction, control the temperature at 400℃ during the process, and adjust according to the characteristics of the ALD precursor and the reaction conditions, the environmental pressure is maintained at 10Torr, the thickness of the dielectric layer film is increased by repeating the ALD cycle, each cycle increases the thickness by 20 angstroms;

[0144] The step 6 uses dry etching, selects an inductively coupled plasma (ICP) etching machine and hydrogen fluoride (HF) as the etching gas to operate, the overall environmental temperature needs to be maintained at 25℃, start the inductively coupled plasma (ICP) etching machine to generate plasma, then input the hydrogen fluoride (HF) etching gas, ensure the flow rate is 50sccm, adjust the reaction chamber pressure to 50mTorr to maintain a stable etching atmosphere, under the discharge power of 300W and the frequency of 13.56MHz, the hydrogen fluoride (HF) reacts with the dielectric layer surface to generate fluoride, thereby achieving etching, after etching is completed, cleaning is performed to remove etching residues;

[0145] The step 7 uses epitaxial growth technology to form a lightly doped N-type semiconductor, the lightly doped N-type semiconductor is silicon, first clean the device and then place the cleaned silicon substrate in the epitaxial growth chamber for subsequent operation, the epitaxial growth chamber is a vacuum or inert gas environment, set the growth temperature at 1300℃, the pressure is a low pressure environment of 100Pa, the flow rate of the silicon source gas is set at 20sccm, the flow rate of hydrogen as the carrier gas is set at 200sccm, during the growth process, introduce phosphine (PH3) as a dopant gas, the doping concentration is 1×10 17 cm -3 , the growth time is set at 120 minutes, after growth is completed, perform a thermal annealing treatment on the epitaxial layer to optimize the crystal structure and electrical properties; the thermal annealing temperature is 900℃, the thermal annealing time is controlled at 40 minutes;

[0146] The step 8 uses dry etching, using a high frequency inductively coupled plasma reactor (ICP-RIE), selecting chlorine (Cl2) as the etching gas, setting the RF power to 200 W, the frequency to 13.56 MHz, the pressure in the etching chamber to 30 mTorr, and etching at 30°C, with an etching rate of 50 nm / min, and then using molecular beam epitaxy (MBE) technology to form a heavily doped P-type semiconductor, which is gallium antimonide (GaSb), first cleaning the silicon substrate for epitaxial growth, then placing the cleaned silicon substrate in the MOCVD reaction chamber for subsequent operation, setting the reaction temperature to 700°C, using trimethyl gallium (TMGa) and arsine (AsH3) as the reaction gas, with a gas volume ratio of 1:12, adding dimethyl zinc (Zn(CH3)2) as a dopant during growth, with a doping concentration of 1x10 20 cm -3 After growth, heat annealing is performed at a temperature of 500°C for 50 minutes, the polycrystalline material is deposited using chemical vapor deposition (CVD) technology, and the polycrystalline material is polycrystalline silicon, first preheating the CVD reaction chamber to 700°C and controlling the pressure in the chamber to 10 1 Torr to facilitate subsequent deposition, introducing dimethylsilane (SiH2(CH3)2) as the silicon source gas at a flow rate of 100 sccm and hydrogen (H2) as the diluent gas at a flow rate of 500 sccm, decomposing the silicon source gas in the reaction chamber and depositing an electrode thin film on the substrate surface, and then annealing the deposited electrode thin film to improve its crystallinity and electrical properties, with a heat annealing temperature of 1000°C and a heat annealing time of 40 minutes.

[0147] The length of the heavily doped N-type semiconductor in step 1 is 80 nm, and the width is 40 nm;

[0148] The length of the polycrystalline material in step 2 is consistent with the length of the substrate 8, and the width is 3 nm;

[0149] The drain contact 7 in step 3 is set at the edge of the substrate 8, with a length of 10 nm, and the length of the semiconductor with the same doping concentration and type as the substrate 8 is 15 nm, and the width is 20 nm;

[0150] The length of the deposited metal in step 4 is 35 nm, and the width is 10 nm;

[0151] The length of the etched region in step 5 is the length of the drain region 6 plus the length of the high dielectric constant oxide layer 4 on both sides, which is 5 nm;

[0152] The vertical part of the biomolecule detection cavity 3 and the high dielectric constant oxide layer 4 formed in step 6 have the same size, the length of the horizontal part of the biomolecule detection cavity 3 on both sides plus the length of the vertical part of the channel 2 is equal to the length of the horizontal part of the channel 2, the width of the horizontal part of the biomolecule detection cavity 3 is 5 nm, the vertical part of the biomolecule detection cavity 3 is placed above the high dielectric constant oxide layer 4, the length is the same as the width of the horizontal part, and the width plus the width of the high dielectric constant oxide layer 4 is equal to the width of the vertical part of the channel 2; the bottom of the high dielectric constant oxide layer 4 is flush with the bottom of the vertical part of the channel 2, and the length is consistent with the length of the vertical part of the biomolecule detection cavity 3;

[0153] The width of the horizontal part of the T-shaped lightly doped N-type semiconductor in step 7 is 40 nm, and the length is 80 nm; the length of the vertical part of the T-shaped lightly doped N-type semiconductor is 15 nm, and the width is 15 nm;

[0154] In step 8, the bottom of the source region 1 is 8 nm above the bottom of the horizontal part of the channel 2, and the source region 1 is inside the horizontal part of the channel 2 on both sides, and the distance between the two sides is 10 nm; the material of the source contact 9 is polysilicon, the length is consistent with the length of the source region 1, and the width is 3 nm.

[0155] Simulation experiment

[0156] Figure 5 The transfer characteristic curve obtained by the biosensor of embodiment 1 for detecting biomolecules with different dielectric constants is shown in the figure, where K=3, 7, and 12 represent biomolecules with different dielectric constants, and K=1 represents the dielectric constant of air, i.e. the case when no biomolecules enter, V DS represents the drain-source voltage; due to the hat structure increasing the area of the tunneling region, the sensor can work at a lower voltage and has a larger on-current. From Figure 5 it can be seen that when detecting biomolecules with K=12, the on-current reaches about 8.71×10 -5 A / μm, when detecting biomolecules with K=7, the on-current reaches about 3.28×10 -6 A / μm, and when detecting biomolecules with K=3, the on-current reaches about 3.12×10 -10 A / μm. Figure 6 The sensitivity comparison chart of the biosensor of embodiment 1 and the traditional TFET biosensor when detecting biomolecules with different dielectric constants is shown. The sensitivity is obtained by calculating the ratio of the saturation on-current when biomolecules with different dielectric constants enter the cavity to the saturation on-current when air enters the cavity, where V GS represents the drain-source voltage, and V DS represents the drain-source voltage. From Figure 6It can be seen that the sensitivity is approximately 10² when detecting biomolecules with K=3, and approximately 6.05 × 10⁻⁶ when detecting biomolecules with K=7. 5 The value is approximately 1.84 × 10⁻⁶ when detecting biomolecules with K = 12. 7 This indicates that the biosensor structure prepared in this invention has higher sensitivity for detecting biomolecules with larger dielectric constants. Compared to traditional TFET biosensors, it achieves an improvement of approximately 2.2 times in detecting biomolecules with K=3, and an improvement of approximately 1.7 × 10⁻⁶ in detecting biomolecules with K=7. 3 This represents an improvement of approximately 8.6 × 10⁻⁶ times compared to traditional TFET biosensors when detecting biomolecules with K = 12. 3 The result shows that the biosensor prepared in this invention has a higher sensitivity, which is twice that of the original.

[0157] Figure 7 The figure shows the transfer characteristic curves obtained by the biosensor of Example 2 detecting biomolecules with different dielectric constants. In the figure, K = 3, 7, 12 represent biomolecules with different dielectric constants, while K = 1 represents the dielectric constant of air, i.e., the case where no biomolecules enter. V DS This represents the drain-source voltage; due to the increased tunneling area caused by the cap structure, the sensor can operate at lower voltages while maintaining a larger on-state current. From Figure 7 As can be seen, approximately 1.23 × 10⁻⁶ was achieved when detecting biomolecules with K = 12. -4 The A / μm ratio reached approximately 2.63 × 10⁻⁶ when detecting biomolecules with K = 7. -6 The A / μm ratio reached approximately 5.05 × 10⁻⁶ when detecting biomolecules with K = 3. -10 A / μm. Figure 8 This is a sensitivity comparison chart between the biosensor of Example 2 and a conventional TFET biosensor in detecting biomolecules with different dielectric constants. This sensitivity is obtained by calculating the ratio of the saturation conduction current when biomolecules with different dielectric constants enter the cavity to the saturation conduction current when air enters the cavity, where V... GS V represents the drain-source voltage. DS This represents the drain-source voltage. (From...) Figure 8 It can be seen that the sensitivity is approximately 124 when detecting biomolecules with K=3, and approximately 6.55 × 10⁻⁴ when detecting biomolecules with K=7. 5 When detecting biomolecules with K=12, the value is approximately 3.08 × 10⁻⁶. 7, indicating that the biosensor structure prepared by the application has higher sensitivity for detecting biological molecules with larger dielectric constant. Compared with the traditional TFET biosensor, the detection of K=3 biological molecules is about 2.7 times higher than the traditional TFET biosensor, the detection of K=7 biological molecules is about 3.0x10 3 times higher than the traditional TFET biosensor, and the detection of K=12 biological molecules is about 1.4x10 4 times higher than the traditional TFET biosensor, indicating that the biosensor prepared by the application has higher sensitivity.

Claims

1. A biosensor having a hat-brim-like vertical tunneling field effect transistor, said biosensor comprising a substrate (8), characterized in that: The upper surface of the substrate (8) is provided with drain region contacts (7) at both ends, the upper surface of the substrate (8) between the two drain region contacts (7) is provided with a drain region (6), the upper surface of the drain region (6) is provided with a T-shaped channel (2), the vertical region of the channel (2) is provided with a high dielectric constant oxide layer (4) at both sides of the bottom end, each high dielectric constant oxide layer (4) is provided with a gate metal (5) away from one side of the channel (2), and the gate metal (5), the high dielectric constant oxide layer (4) and the channel (2) form a bent biomolecule detection cavity (3); The horizontal region of the channel (2) is embedded in the source region (1), the source region (1) is an outer eave, the channel (2) is an inner eave, and a hat eave structure is formed, the upper surface of the source region (1) is provided with a source region contact (9), or the source region (1) is embedded in the horizontal region of the channel (2), the channel (2) is an outer eave, and the source region (1) is an inner eave to form a hat eave structure.

2. The biosensor having a hat-brim-shaped vertical tunneling field effect transistor according to claim 1, characterized in that: The source region (1) is a P-type heavily doped region, adopts GaSb material, and has a doping concentration of 5x10 18 cm -3 ~1x10 20 cm -3 . The channel (2) is an N-type lightly doped region made of Si material, with a carrier concentration of 1 x 10 15 cm -3 ~ 1 x 10 17 cm -3 . The drain region (6) and the substrate (8) are both N-type heavily doped regions with a doping concentration of 1 x 10 18 cm -3 ~ 5 x 10 19 cm -3 . The high dielectric constant oxide layer (4) is HfO2 or Al2O3; The gate metal (5) is chromium or hafnium; The source region contact (9) and the drain region contact (7) are both polysilicon.

3. The biosensor having a hat-brim-shaped vertical tunneling field effect transistor according to claim 1, wherein: The biomolecule sensor is arranged in an axisymmetric manner, when the horizontal region of the channel (2) is embedded in the source region (1), the length of the source region (1) is 40nm-80nm, and the width is 20nm-40nm; the length of the horizontal part of the channel (2) is 10nm-16nm smaller than the length of the source region (1), the bottom of the horizontal part of the channel (2) is flush with the bottom of the source region (1), and the width is 10nm-15nm; the length of the vertical part of the channel (2) is 10nm-15nm, and the width is 10nm-15nm; When the source region (1) is embedded in the horizontal region of the channel (2), the length of the horizontal part of the channel (2) is 40nm-80nm, the width is 20nm-40nm, the length of the vertical part of the channel (2) is 10nm-15nm, and the width is 10nm-15nm; the bottom of the source region (1) is 5nm-8nm away from the bottom of the horizontal part of the channel (2), and the length of the source region (1) is 10nm-16nm smaller than the length of the horizontal part of the channel (2); The length of the drain region (6) is the same as the length of the vertical part of the channel (2), and the width is 10nm-20nm; The length of the substrate (8) is 40nm-80nm, and the width is 20nm-40nm; The length of the horizontal part of the biomolecule detection cavity (3) is equal to the length of the horizontal part of the channel (2) plus the length of the vertical part of the channel (2), the width of the horizontal part of the biomolecule detection cavity (3) is 3nm-5nm; the length of the vertical part of the biomolecule detection cavity (3) and the length of the high dielectric constant oxide layer (4) are the same as the width of the horizontal part of the biomolecule detection cavity (3), and the width of the vertical part of the biomolecule detection cavity (3) plus the width of the high dielectric constant oxide layer (4) is equal to the width of the vertical part of the channel (2); The bottom of the high dielectric constant oxide layer (4) is flush with the bottom of the vertical part of the channel (2). The bottom of the gate metal (5) is level with the bottom of the high dielectric constant oxide layer (4), and the side is level with the side of the biomolecule detection cavity (3); Each drain region contact (7) is arranged at the edge of the substrate (8), with a length of 8-10 nm and a width of 2-3 nm; The source region contact (9) has the same length as the source region (1), with a width of 2-3 nm.

4. A method for fabricating a biosensor with a hat-shaped vertical tunneling field effect transistor according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Prepare a substrate (8) with a heavily doped N-type semiconductor; Step 2: Deposit a layer of polycrystalline material on the substrate (8) prepared in step 1; Step 3: Etch the polycrystalline material deposited in step 2 in the middle, forming drain region contacts (7) at both ends of the substrate (8), and growing a semiconductor with the same doping concentration and type as the substrate (8) in the central region of the substrate (8) as a drain region (6); Step 4: Deposit a layer of metal on the drain region (6) grown in step 3; Step 5: Etch the metal deposited in step 4 in the middle, leaving the metal at both ends as the gate metal (5), and depositing a layer of dielectric material with high dielectric constant in the central region; Step 6: Etch the dielectric material deposited in step 5 to form a biomolecule detection cavity (3) and a high dielectric constant oxide layer (4); Step 7: When the channel (2) is embedded in the horizontal region of the source region (1), grow a T-shaped lightly doped N-type semiconductor in the area etched in step 6 as the channel (2); When the source region (1) is embedded in the horizontal region of the channel (2), grow a T-shaped lightly doped N-type semiconductor in the area etched in step 6; Step 8: When the channel (2) is embedded in the source region (1), grow a layer of heavily doped P-type semiconductor around the horizontal part of the T-shaped channel (2) grown in step 7 as the source region (1), and deposit a layer of polycrystalline material on the source region (1) as the source region contact (9); When the source region (1) is embedded in the horizontal region of the channel (2), etch the central region of the horizontal part of the T-shaped N-type semiconductor grown in step 7 to form the channel (2), and then grow a layer of heavily doped P-type semiconductor in the etched area as the source region (1), and deposit a layer of polycrystalline material on the source region (1) as the source region contact (9).

5. The preparation method of the biomolecule sensor with the hat-shaped vertical tunneling field effect transistor according to claim 4, wherein: The heavily doped N-type semiconductor in step 1 is silicon, and phosphorus (P) is selected as the dopant, with a doping concentration of 1×10 18 cm -3 ~ 5×10 19 cm -3 , the control injection energy is 50keV~200keV, the whole ion implantation process is kept at 20℃~25℃, after the ion implantation is completed, heat annealing treatment is carried out to activate the phosphorus ions, the heat annealing temperature is at 600℃~1000℃, and the heat annealing time is controlled at 30 minutes~60 minutes; The step 2 of depositing the polycrystalline material is by using a chemical vapor deposition (CVD) process, first preheating the CVD reaction chamber to 500-700°C, and controlling the chamber pressure at 10 -2 Torr-10 1 Torr to facilitate subsequent deposition, introducing dimethylsilane (SiH2(CH3)2) as a silicon source gas at a flow rate of 50-100 seem, and hydrogen (H2) as a diluent gas at a flow rate of 200-500 seem, decomposing the silicon source gas in the reaction chamber by chemical reaction and depositing an electrode thin film on the substrate surface, and then performing a thermal annealing process on the deposited electrode thin film at a thermal annealing temperature of 500-1000°C for a time period of 20-40 minutes. The etching of step 3 uses a dry etching technique, and high-frequency inductively coupled plasma reactive ion etching (ICP-RIE) is used, with chlorine (Cl2) as the etching gas, RF power set at 100 W to 300 W, frequency at 13.56 MHz, etching chamber pressure at 10 mTorr to 50 mTorr, etching at 25°C to 30°C, etching rate at 30 nm / min to 50 nm / min, and the same semiconductor with the same doping concentration and type as the substrate (8) is generated by epitaxial growth process using silicon material. First, the silicon substrate for epitaxial growth is cleaned, and then the cleaned silicon substrate is placed in the epitaxial growth chamber for subsequent operation. The epitaxial growth chamber is a vacuum or inert gas environment, the growth temperature is set at 1100°C to 1300°C, the pressure is set at a low pressure environment of 90 Pa to 100 Pa, the flow rate of the silicon source gas is set at 15 sccm to 20 sccm, the flow rate of hydrogen as the carrier gas is set at 180 sccm to 200 sccm, and in the growth process, phosphine (PH3) is introduced as a dopant gas, with a doping concentration of 1×10 18 cm -3 ~ 5×10 19 cm -3 , the growth time is set at 30 minutes to 120 minutes, and after growth, it is subjected to thermal annealing treatment, with a thermal annealing temperature of 400°C to 800°C and a thermal annealing time of 10 minutes to 30 minutes. The step 4 of depositing metal is using a reactive sputtering process, the deposited metal is metal chromium or metal hafnium, the reactive sputtering process is using a magnetron sputtering system to deposit, first heating the target material to 200-400℃ to increase the evaporation rate of the metal, while controlling the temperature of the substrate at 100-300℃ to avoid thermal damage to the film on the substrate, the pressure of the sputtering chamber is set at 10 -6 Torr-10 -8 Torr, start the sputtering system, heat the target material of the deposited metal and apply an electric field, so that the target material is sputtered from the surface of the target gun to the silicon substrate, set the sputtering power at 100-200W to form the required metal film on the semiconductor surface, after the sputtering process is completed, release the vacuum chamber gas and take out the semiconductor substrate, and use characterization techniques to evaluate the morphology, composition and bonding state of the metal film, the characterization techniques include SEM, XPS, to ensure the quality and stability of the gate electrode; The step 5 etching metal process is a metal gate etching process, selecting a mixed gas of Cl2 and Br2, the gas volume ratio is (1-3):1, setting RF power 200-300 W, frequency 13.56 MHz, the pressure in the etching chamber is 20-40 mTorr, the etching rate is 50-70 nm / min, the process of depositing dielectric material is atomic layer deposition (ALD), the deposited dielectric material is HfO2 or Al2O3, the bottom of the dielectric material is flat with the bottom of the gate metal (5), the width is the sum of the width of the gate metal (5) and the length of the high dielectric constant oxide layer (4), the atomic layer deposition (ALD) process first performs chemical cleaning or hydrogen treatment on the semiconductor material to remove oxides and organic residues, ensures the best surface acceptance, uses hafnium trimethoxide or aluminum trimethoxide as the precursor of the deposited dielectric layer, introduces the precursor into the reaction chamber, makes the precursor adsorb on the silicon surface, introduces oxygen or nitrogen, removes unreacted precursors and by-products, introduces water vapor as an oxidizing agent to react with the adsorbed precursor to form a dielectric layer film, repeats the purification step to remove by-products and unreacted gas generated during the reaction, controls the temperature at 200-400°C during the process, and adjusts according to the characteristics of the ALD precursor and the reaction conditions, the environmental pressure is maintained at 2-10 Torr, and the thickness of the dielectric layer film is increased by repeating the ALD cycle, each cycle increases the thickness by 5-20 angstroms; The step 6 uses dry etching, selects an inductively coupled plasma (ICP) etching machine and hydrogen fluoride (HF) as the etching gas for operation, the overall environmental temperature needs to be maintained at 20-25°C, starts the inductively coupled plasma (ICP) etching machine to generate plasma, then inputs the hydrogen fluoride (HF) etching gas, ensures the flow rate is 40-50 sccm, adjusts the reaction chamber pressure to 40-50 mTorr to maintain a stable etching atmosphere, under a discharge power of 100-300 W and a frequency of 13.56 MHz, hydrogen fluoride (HF) reacts with the dielectric layer surface to generate fluoride, thereby achieving etching, and cleaning is performed after etching to remove etching residues; The step 7 uses an epitaxial growth technique to form a lightly doped N-type semiconductor, which is silicon. The device is first cleaned and then the cleaned silicon substrate is placed in an epitaxial growth chamber for subsequent operation. The epitaxial growth chamber is a vacuum or inert gas environment. The growth temperature is set to 1100-1300°C. The pressure is set to a low pressure environment of 90-100 Pa. The flow rate of the silicon source gas is set to 15-20 sccm. The flow rate of hydrogen as a carrier gas is set to 180-200 sccm. During the growth process, phosphine (PH3) is introduced as a dopant gas. The doping concentration is 1×10 15 cm -3 -1×10 17 cm -3 . The growth time is set to 30-120 minutes. After the growth is completed, the epitaxial layer is subjected to a thermal annealing process to optimize the crystal structure and electrical properties. The thermal annealing temperature is 600-900°C. The thermal annealing time is controlled to 20-40 minutes. The step 8 is to form a heavily doped P-type semiconductor of GaSb in the horizontal region of the channel (2) by using the molecular beam epitaxy (MBE) technique, and then to etch the heavily doped P-type semiconductor of GaSb in the horizontal region of the channel (2) by using the dry etching method with the high frequency inductively coupled plasma reactive ion etching (ICP-RIE) and selecting Cl2 as the etching gas, setting the RF power at 100-200 W, the frequency at 13.56 MHz, the pressure in the etching chamber at 20-30 mTorr, and etching at 25-30°C with the etching rate of 30-50 nm / min. Then, a heavily doped P-type semiconductor of GaSb is formed by using the molecular beam epitaxy (MBE) technique. First, the silicon substrate for epitaxial growth is cleaned, and then the cleaned silicon substrate is placed in the MOCVD reaction chamber for subsequent operation, with the reaction temperature set at 500-700°C, TMGa and AsH3 used as the reaction gas with the gas volume ratio of 1:(8-12), dimethyl germanium or dimethyl zinc (Zn(CH3)2) added as the dopant during the growth process, the doping concentration being 5×10 18 cm -3 ~1×10 20 cm -3 , and the thermal annealing temperature being 300-500°C and the time being 30-50 min. The polycrystalline material is deposited by using the chemical vapor deposition (CVD) technique, and the polycrystalline material is polycrystalline silicon. First, the CVD reaction chamber is preheated to 500-700°C, and the pressure in the chamber is controlled at 10 -2 Torr~10 1 Torr to facilitate the subsequent deposition. Dimethyl silane (SiH2(CH3)2) is introduced as the silicon source gas with the flow rate set at 50-100 sccm, and hydrogen (H2) is used as the diluent gas with the flow rate set at 200-500 sccm. The silicon source gas is decomposed in the reaction chamber and deposited on the surface of the substrate to form an electrode thin film. Then, the electrode thin film after deposition is annealed to improve its crystallinity and electrical properties, with the thermal annealing temperature being 500-1000°C and the thermal annealing time being 20-40 min.

6. The preparation method of the biosensor with a hat-shaped vertical tunneling field effect transistor according to claim 4, characterized in that: The length of the heavily doped N-type semiconductor in step 1 is 40-80 nm, and the width is 20-40 nm; The length of the polycrystalline material in step 2 is consistent with the length of the substrate (8), and the width is 2-3 nm; The drain contact (7) in step 3 is arranged at the edge of the substrate (8), the length is 8-10 nm, the length of the semiconductor with the same doping concentration and type as the substrate (8) is 10-15 nm, and the width is 10-20 nm; The length of the deposited metal in step 4 is 30-35 nm, and the width is 7-10 nm; The length of the etching region in step 5 is the length of the drain region (6) plus the length of the high dielectric constant oxide layer (4) on both sides, which is 3-5 nm; In step 6, the length of the horizontal part of the biomolecule detection cavity (3) on both sides plus the length of the vertical part of the channel (2) is equal to the length of the horizontal part of the channel (2), the width of the horizontal part of the biomolecule detection cavity (3) is 3-5 nm, the vertical part of the biomolecule detection cavity (3) is placed above the high dielectric constant oxide layer (4), the length is the same as the width of the horizontal part, and the width plus the width of the high dielectric constant oxide layer (4) is equal to the width of the vertical part of the channel (2); the bottom of the high dielectric constant oxide layer (4) is flush with the bottom of the vertical part of the channel (2), and the length is consistent with the length of the vertical part of the biomolecule detection cavity (3); In step 7, when the horizontal region of the channel (2) is embedded in the source region (1), the length of the vertical part of the channel (2) is 10-15 nm, and the width is 10-15 nm; the length of the horizontal part of the channel (2) is the same as the length of the drain region (6) and the length of the horizontal part of the biomolecule detection cavity (3) on both sides; When the source region (1) is embedded in the horizontal region of the channel (2), the width of the horizontal part of the T-shaped lightly doped N-type semiconductor is 20-40 nm, and the length is 40-80 nm; the length of the vertical part of the T-shaped lightly doped N-type semiconductor is 10-15 nm, and the width is 10-15 nm; In step 8, when the horizontal region of the channel (2) is embedded in the source region (1), the length of the source region (1) is 40-80 nm, and the width is 20-40 nm; the distance between the left and right sides of the source region (1) and the left and right sides of the horizontal part of the channel (2) is the same, which is 5-8 nm; the length of the source region contact (9) is consistent with the length of the source region (1), and the width is 2-3 nm; When the source region (1) is embedded in the horizontal region of the channel (2), the bottom of the source region (1) is 5-8 nm above the bottom of the horizontal part of the channel (2), and the two sides of the source region (1) are inside the two sides of the horizontal part of the channel (2), and the distance between the two sides is 5-10 nm; the material of the source region contact (9) is polysilicon, the length is consistent with the length of the source region (1), and the width is 2-3 nm.

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