Schottky barrier tunneling field effect transistor biosensor with recessed grid and bidirectional current conduction

Abstract

A Schottky barrier tunneling field effect transistor biosensor with a sunken grid electrode and bidirectional current conduction comprises a channel, a groove is formed in the middle of the channel, protruding parts are arranged on the two sides of the groove, source electrodes are arranged on the tops of the protruding parts respectively, the two source electrodes and a drain electrode form bidirectional current conduction, and the drain electrode current of the device is increased; a concave gate dielectric layer is arranged at the upper part in the groove, so that the off-state current of the device is reduced; a grid electrode is arranged above the sunken grid electrode dielectric layer, biomolecule detection cavities are formed in the two sides of the grid electrode and above the grid electrode dielectric layer, and a drain electrode is arranged below the channel; the two sources and the drain on the two sides of the grid form bidirectional current conduction, the drain current sensitivity and the drain current sensitivity of the device are improved, the off-state current when K is equal to 1 is 2.1 * 10 <-18 > A / mu m, and compared with a traditional structure, the off-state current is reduced by 2.2 times; when K is equal to 12, the turn-on current of the transistor is 2.6 * 10 <-6 > which is reduced by 113% compared with 2.3 * 10 <-6 > of a traditional structure, and the transistor has the advantages of low off-state current, high drain current sensitivity and simple manufacturing process.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction. Background Art

[0002] Tunneling field-effect transistors (TFETs) and Schottky tunneling field-effect transistors (SB-FETs) are considered core components for next-generation biosensors due to their high transconductance and low subthreshold swing. However, TFET fabrication is complex, and the steep doping interface between the source, drain, and channel requires high-precision ion implantation, which can easily introduce interface defects, leading to decreased device stability and performance drift. Furthermore, even slight deviations in doping concentration can significantly affect the tunneling probability, complicating mass production.

[0003] In contrast, SB-FET uses metal silicide as the source and drain material, and simplifies the doping steps through a self-aligned process, reducing the interface state density and process complexity. The low work function characteristics of metal silicide can enhance the transport efficiency of carriers in the channel, while reducing interface noise interference, improving the signal-to-noise ratio and repeatability of the device. In addition, the metal passivation layer design of SB-FET can effectively suppress the interference of ambient humidity or ions in biological samples on the gate electric field, extending the device life and widening the detection dynamic range. These advantages make it show great potential in portable point-of-care testing (POCT) devices, providing key technical support for the development of a new generation of high-throughput, low-cost biosensing platforms.

[0004] Patent application number 202011516842.4 discloses a "biosensor based on a nanosheet stack field-effect transistor and its preparation method." Three vertically stacked nanosheets form a channel, with a nanocavity etched near the source end. This structure overcomes the short-channel effect, but suffers from lower sensitivity.

[0005] The journal Nanoscale Research Letters published a technical solution, "Simulation and Performance Analysis of Dielectric Modulated Dual Source Trench Gate TFET Biosensor," which uses a recessed gate and an N+ doped region to improve the device's sensitivity in detecting biomolecules. However, the device's fabrication process is complex and subject to significant process fluctuations.

[0006] The journal IEEE Transactions on Nanobioscience published a technical solution, "L-Shaped High-Performance Schottky BarrierFET as Dielectrically Modulated Label-Free Biosensor." This device utilizes an L-shaped vertical channel structure, with the source and drain electrodes made of ErSi1.7 material forming Schottky contacts with the channel. This device exhibits high sensitivity, but the fabrication process is complex.

[0007] Existing biosensors based on devices such as MOSFET and TFET have complex preparation processes and cannot increase the drain current of the device while maintaining the off-state current, so they cannot improve the operating speed and sensing sensitivity of the device. Summary of the Invention

[0008] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a Schottky barrier tunneling field-effect transistor biosensor with a recessed gate and bidirectional current conduction. The gate is recessed into the channel, so that the off-state current of the device is reduced. The dual source and drain electrodes on both sides of the recessed gate constitute bidirectional current conduction, which increases the drain current of the device. The process complexity is low, the drain current of the device is increased, and the sensitivity of the field-effect transistor in detecting biomolecules is improved.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A Schottky barrier tunneling field-effect transistor biosensor with a recessed gate and bidirectional current conduction includes: a channel 1, a recess 7 is provided in the middle of the channel 1, protrusions are provided on both sides of the recess 7, and a source 2 is provided on the top of each protrusion; a recessed gate dielectric layer 5 is provided in the recess 7, a gate 4 is provided above the recessed gate dielectric layer 5, biomolecule detection cavities 6 are provided on both sides of the gate 4 and above the gate dielectric layer 5, and a drain 3 is provided below the channel 1.

[0011] The depth of the groove 7 is 5 nm to 10 nm.

[0012] The gate dielectric layer 5 is made of any one of HfO 2 , Al 2 O 3 or SiO 2 .

[0013] The source electrode 2 and the drain electrode 3 are made of metal silicide, including erbium silicide and nickel silicide.

[0014] The gate 4 is made of metal materials including hafnium and aluminum.

[0015] When biomolecules are injected into the biomolecule detection cavity 6, the drain current sensitivity is:

[0016]

[0017] in, is the drain current sensitivity, I bio ds The drain current when biomolecules are injected into the biomolecule detection cavity 6, I air ds It is the drain current when no biomolecules are injected into the biomolecule detection cavity 6 .

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The gate is recessed into the channel, reducing the off-state current of the device. The off-state current of the conventional structure with K = 1 is 4.62 × 10-18 A / μm, while the off-state current of the present invention with K = 1 is 2.1 × 10-18 A / μm. Compared with the conventional structure, the off-state current of the present invention is reduced by 2.2 times.

[0020] (2) The dual source and drain electrodes on both sides of the recessed gate form a bidirectional current conduction, which increases the drain current of the device. Figure 2 As shown, when K=12, the turn-on current of the present invention is 2.6×10-6, which is 113% lower than 2.3×10-6 of the traditional structure, so the drain current sensitivity is improved.

[0021] (3) The present invention is based on a Schottky barrier field effect transistor, which has a simple preparation process and uses metal silicide materials for the source and drain, thus avoiding heavy doping and improving the life of the device.

[0022] In summary, the Schottky barrier tunneling field-effect transistor biosensor with a recessed gate and bidirectional current conduction of the present invention has the advantages of low off-state current, high drain current sensitivity and simple manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of the present invention.

[0024] Figure 2 This is a curve diagram of the computer-aided design software simulation characteristics of the present invention.

[0025] Figure 3 The figure is a computer-aided design software simulation characteristic curve diagram of the present invention and the traditional structure when K=1 and K=12.

[0026] Markings in the figure: 1 is the channel, 2 is the source, 3 is the drain, 4 is the gate, 5 is the gate dielectric layer, 6 is the biomolecule detection cavity, and 7 is the groove. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] See also Figure 1 A Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction includes: a channel 1, a recess 7 is provided in the middle of the channel 1, protrusions are provided on both sides of the recess 7, and a source 2 is provided on the top of each protrusion, a recessed gate dielectric layer 5 is provided in the recess 7, a gate 4 is provided above the recessed gate dielectric layer 5, biomolecule detection cavities 6 are provided on both sides of the gate 4 and above the gate dielectric layer 5, and a drain 3 is provided below the channel 1.

[0029] The depth of the groove 7 is 5 nm to 10 nm.

[0030] The gate dielectric layer 5 is made of any one of HfO 2 , Al 2 O 3 or SiO 2 .

[0031] The source electrode 2 and the drain electrode 3 are made of metal silicide, including erbium silicide and nickel silicide.

[0032] The gate 4 is made of metal materials including hafnium and aluminum.

[0033] Drain current sensitivity is an important indicator for detecting the performance of biosensors. The drain current sensitivity formula is: Among them S Ids is the drain current sensitivity, I bio ds The drain current when biomolecules are injected into the biomolecule detection cavity 6, I air ds It is the drain current when no biomolecules are injected into the biomolecule detection cavity 6 .

[0034] The working principle of the present invention is:

[0035] The gate 4 of the present invention is recessed into the channel 1, reducing the device's off-state current. The dual source 2 and drain 3 on either side of the gate 4 form bidirectional current conduction, increasing the device's drain current and drain current sensitivity. Schottky barrier tunneling field-effect transistors use metal silicide as the source and drain materials to form Schottky contacts. Increasing gate voltage exacerbates channel band bending, reduces the tunneling barrier width, and increases the tunneling probability exponentially.

[0036] Simulation experiment:

[0037] See also Figure 2 、 Figure 3, the simulation results of Schottky barrier tunneling field-effect transistor biosensors with recessed gates and bidirectional current conduction were obtained using Sentaurus TCAD simulation software. In the Sentaurus TCAD simulation platform, the basic semiconductor equations (Poisson's equation, carrier continuity equation, and current density equation) were solved through self-consistent coupling to establish a quantitative relationship between the device's electrostatic potential distribution, carrier transport, and electrical output characteristics, and visualize the parameters of the electrical properties. The Shockley-Read-Hall (SRH) model was used to characterize defect-assisted recombination, and the Auger recombination model was introduced to describe non-radiative recombination under high carrier concentrations; the ElectronMobility and HoleMobility models (including doping dependence, high-field saturation, and interface scattering effects) were used to accurately simulate the carrier transport dynamics; the BandGapNarrowing (BGN) model was activated to quantify the heavily doped source / drain regions (>1×10 19 cm -3 ) bandgap shrinkage effect. Through simulation, it can be obtained that the off-state current of the present invention when K=1 is 2.1×10 -18 A / μm, the off-state current of the traditional structure when K=1 is 4.62×10 -18 A / μm, compared with the traditional structure, the off-state current of the present invention is reduced by 2.2 times. When K=12, the on-state current of the present invention is 2.6×10 -6 , compared with the 2.3×10 -6 , which is reduced by 113%, so the drain current sensitivity is improved. In summary, the Schottky barrier tunneling field effect transistor biosensor with recessed gate and bidirectional current conduction has improved performance compared with the traditional structure.

[0038] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction, characterized in that: include: A channel (1) is provided with a groove (7) in the middle of the channel (1), with protrusions on both sides of the groove (7), and source electrodes (2) respectively provided on the tops of the protrusions, a recessed gate dielectric layer (5) is provided in the groove (7), a gate electrode (4) is provided above the recessed gate dielectric layer (5), biomolecule detection cavities (6) are provided on both sides of the gate electrode (4) and above the gate dielectric layer (5), and a drain electrode (3) is provided below the channel (1).

2. A Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction according to claim 1, characterized in that: The depth of the groove (7) is 5nm-10nm.

3. The Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction according to claim 1, characterized in that: The gate dielectric layer (5) is made of any one of HfO2, Al2O3 or SiO2.

4. The Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction according to claim 1, characterized in that: The source electrode (2) and the drain electrode (3) are made of metal silicide, including erbium silicide and nickel silicide.

5. The Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction according to claim 1, characterized in that: The gate (4) is made of metal materials including hafnium and aluminum.

6. The Schottky barrier tunneling field effect transistor biosensor with a recessed gate and bidirectional current conduction according to claim 1, characterized in that: When biomolecules are injected into the biomolecule detection cavity (6), the drain current sensitivity is: in, is the drain current sensitivity, I bio ds The drain current when biomolecules are injected into the biomolecule detection cavity 6, I air ds It is the drain current when no biomolecules are injected into the biomolecule detection cavity (6).

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