Vertical biosensor based on undoped tunneling field effect transistor
By designing a vertical biosensor using undoped tunneling field-effect transistors (TFETs), employing In0.53Ga0.47As and In0.52Al0.48As materials, and combining vertical nanocavities with metal electrodes, the problems of weak anti-interference capability and low detection accuracy of TFET biosensors are solved, achieving high sensitivity and low power consumption for biomolecule detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LANZHOU JIAOTONG UNIV
- Filing Date
- 2025-04-23
- Publication Date
- 2026-04-21
AI Technical Summary
Existing TFET biosensors have weak anti-interference capabilities when examining biomolecules, which affects detection accuracy. Furthermore, their high device complexity makes it difficult to achieve low power consumption and high sensitivity.
A vertical biosensor design employing undoped tunneling field-effect transistors uses In0.53Ga0.47As as the host material, combined with an In0.52Al0.48As barrier layer and an HfO2 dielectric layer to introduce a vertical nanocavity. Platinum and hafnium metals are used as source and drain electrodes, and the electron tunneling rate and biomolecular sensitivity are improved through fin-type channel layers and charged plasma principles.
It improves the on-state current and switching current ratio of the device, reduces the impact of heat generation, enhances the integration of biomolecules with the cavity, improves detection stability and sensitivity, and reduces power consumption.
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Figure CN224152405U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microelectronic device technology, and in particular to a vertical biosensor based on an undoped tunneling field-effect transistor. Background Technology
[0002] Compared with traditional biosensors (optical biosensors, magnetic biosensors, etc.), dielectric modulation biosensors have advantages such as miniaturization, low cost, strong robustness, easy integration and compatibility with CMOS technology, and have attracted widespread attention from researchers in pathogen detection and healthcare.
[0003] The dielectric modulation biosensor contains a nanocavity (i.e., a biocavity) between the gate oxide and the gate electrode. When the biomolecule to be detected enters the nanocavity, it adheres to the gate oxide, thereby achieving dielectric modulation. Furthermore, the dielectric constant (k) and positive / negative charge density (N) of the biomolecule are also considered. bio Differences in capacitance can cause changes in the effective gate oxide capacitance at the tunnel junction in the channel, thereby affecting the electrical properties of the biosensor (e.g., on-state current (I0)). on Threshold voltage (V) th ), mean subthreshold swing (SS) avg Dielectric modulation biosensors produce varying degrees of changes in molecules, ultimately achieving the purpose of detection. Moreover, compared to biological detection methods such as antibody binding, dielectric modulation biosensors can detect specific biomolecules faster and can perform repeated detections, showing broad application prospects in the detection of infectious diseases.
[0004] However, dielectric modulation biosensors are typically designed based on MOSFETs, whose subthreshold swing (SS) cannot be lower than 60 mV / dec at room temperature, affecting their detection speed; and at the nanoscale, they are susceptible to short-channel effects, which limit the reduction of static power consumption and degrade their device performance.
[0005] Tunneling field-effect transistors (TFETs), based on the band-to-band tunneling mechanism, overcome the limitations of MOSFETs and offer fast response times, leading to their widespread application in biosensor design. Traditional TFET biosensors operate based on point tunneling (PT), achieving signal-to-weight ratios (SS) below 60 mV / dec. However, higher bias voltages are required to enhance sensitivity, hindering low-power applications. Furthermore, achieving higher sensitivity necessitates etching two or more nanocavities below the gate electrode, significantly increasing device fabrication complexity. Moreover, previously reported TFET biosensors are mostly lateral structures, which hinder the injection and filling of biomolecules within the cavities, thus affecting the biosensor's sensitivity. Additionally, the length of the cavities in lateral biosensors simultaneously influences both device performance and integration density, creating a mutually restrictive relationship.
[0006] TFET biosensors often use indirect tunneling materials with large band gaps, such as Si and Ge. The heat generated during tunneling significantly impacts the accuracy of biomolecule detection. Furthermore, etching multiple lateral nanocavities beneath the gate electrode increases the complexity of device fabrication, placing high demands on the fabrication process. Most TFET biosensors operate based on point tunneling (PT), resulting in an on-state current I... on The low on / off ratio and small switching ratio result in weak anti-interference ability when inspecting biomolecules (i.e., the slight change in the on-state current caused by impure or non-uniform injection of biomolecules into the cavity can cause a large change in the on / off ratio, which may lead to errors in the determination of biomolecule type). Utility Model Content
[0007] This invention provides a vertical biosensor based on an undoped tunneling field-effect transistor (TFET), which addresses the technical problem that existing TFET biosensors have weak anti-interference capabilities when detecting biomolecules, significantly impacting detection accuracy. It achieves the goal of designing a novel vertical biosensor that enhances the device's on-state current sensitivity, threshold voltage sensitivity, and average subthreshold swing sensitivity while reducing power consumption.
[0008] This invention provides a vertical biosensor based on an undoped tunneling field-effect transistor, comprising:
[0009] Horizontal channel layer;
[0010] A vertical channel layer is fixedly positioned at the middle of the surface of the horizontal channel layer, and a U-shaped groove is formed at the bottom end of the vertical channel layer corresponding to the horizontal channel layer.
[0011] A barrier layer is embedded in the U-shaped groove;
[0012] The dielectric layer includes a first dielectric layer and a second dielectric layer, the first dielectric layer and the second dielectric layer having an L-shaped structure, and the first dielectric layer and the second dielectric layer being fixedly disposed on adjacent surfaces on both sides of the horizontal channel layer and the vertical channel layer, respectively.
[0013] The gate is fixedly disposed on the side of the dielectric layer away from the horizontal channel layer and the vertical channel layer;
[0014] The electrodes are fixedly disposed on both sides of the horizontal channel layer.
[0015] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the horizontal channel layer and the vertical channel layer are fin-type channel layers, and the material of the horizontal channel layer and the vertical channel layer is In. 0.53 Ga 0.47 As.
[0016] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the barrier layer is made of In... 0.52 Al 0.48 As.
[0017] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: a first dielectric layer is fixedly disposed on the left side of the vertical channel layer and the upper surface of the horizontal channel layer adjacent thereto; a second dielectric layer is fixedly disposed on the right side of the vertical channel layer and the upper surface of the horizontal channel layer adjacent thereto; the thickness of the vertical end of the first dielectric layer is greater than the thickness of the vertical end of the second dielectric layer.
[0018] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the gate includes a sensing gate, a tunneling gate, and a control gate. The sensing gate is fixedly disposed on the side of the first dielectric layer away from the vertical channel layer. The control gate is fixedly disposed on the side of the second dielectric layer away from the horizontal channel layer. The tunneling gate is vertically fixedly disposed on the side of the control gate away from the second dielectric layer. The tunneling gate is parallel to the vertical end of the second dielectric layer. A bio-cavity is formed between the tunneling gate and the second dielectric layer.
[0019] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the electrode includes a source and a drain, the source is fixedly disposed on one side wall of the horizontal channel layer near the sensing gate, and the drain is fixedly disposed on one side wall of the horizontal channel layer near the control gate.
[0020] The beneficial effects of this utility model are:
[0021] This invention provides a vertical biosensor based on undoped tunneling field-effect transistors (TEPTs). The main material is a narrow-bandgap direct tunneling semiconductor, which improves the electron tunneling rate and reduces heat generation, thereby increasing the on-state current and switching current ratio, and reducing the change in dielectric constant of biomolecules within the bio-cavity caused by heat generation, thus improving the stability of the device's detection. Simultaneously, based on the principle of charged plasma, the electron and hole layers of the finned channel can be induced by selecting metals with different work functions. Since the dielectric constants of the filling biomolecules differ, the ability of the tunneling gate to sense charges also changes, improving the device's sensitivity to detect different biomolecules. Furthermore, the introduction of a vertical nano-bio-cavity allows more biomolecules to enter the nano-bio-cavity under gravity, further enhancing the sensor's sensitivity.
[0022] To reduce the impact of gate leakage on sensitivity and enhance the integration of biomolecules with the nanocavity, the thickness of HfO2 inside the cavity is set to 2.5 nm. For the source and drain regions of the device, to avoid random doping fluctuations and reduce complex thermal budgets and fabrication difficulties, this invention uses platinum and hafnium metals to induce the source and drain regions respectively, and uses them as the source and drain metals. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the structure of a vertical biosensor based on an undoped tunneling field-effect transistor.
[0025] Figure label:
[0026] 1. Horizontal channel layer; 2. Vertical channel layer; 3. Barrier layer; 4. Dielectric layer; 5. Gate; 501. Sensing gate; 502. Tunneling gate; 503. Control gate; 6. Electrode; 601. Source; 602. Drain; 7. Biocavity. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0028] In the description of the embodiments of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0029] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model based on the specific circumstances.
[0030] In this embodiment of the utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0031] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0032] The following is combined with Figure 1 The embodiments shown illustrate the technical solution of this utility model:
[0033] This invention provides a vertical biosensor based on an undoped tunneling field-effect transistor, comprising: a horizontal channel layer 1; a vertical channel layer 2, vertically fixedly disposed at the middle position of the surface of the horizontal channel layer 1, with a U-shaped groove formed at the bottom end of the vertical channel layer 2 corresponding to the horizontal channel layer 1; a barrier layer 3, embedded in the U-shaped groove; a dielectric layer 4, including a first dielectric layer 4 and a second dielectric layer 4, the first dielectric layer 4 and the second dielectric layer 4 having an L-shaped structure, the first dielectric layer 4 and the second dielectric layer 4 being fixedly disposed on adjacent surfaces on both sides of the horizontal channel layer 1 and the vertical channel layer 2; a gate 5, fixedly disposed on the side of the dielectric layer 4 away from the horizontal channel layer 1 and the vertical channel layer 2; and electrodes 6, fixedly disposed on both side walls of the horizontal channel layer 1.
[0034] It is understood that this utility model provides a vertical biosensor based on an undoped tunneling field-effect transistor, with a horizontal channel layer 1 and a vertical channel layer 2 as the main body, and a hafnium dioxide dielectric layer 4, as well as a gate 5 and an electrode 6 disposed on its surface to improve the sensitivity of the sensor.
[0035] According to this utility model, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: a horizontal channel layer 1 and a vertical channel layer 2 are channel layers, and the material of the horizontal channel layer 1 and the vertical channel layer 2 is In. 0.53 Ga 0.47 As.
[0036] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the barrier layer 3 is made of In... 0.52 Al 0.48 As.
[0037] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: a first dielectric layer 4 is fixedly disposed on the left side of the vertical channel layer 2 and the upper surface of the horizontal channel layer 1 adjacent thereto; a second dielectric layer 4 is fixedly disposed on the right side of the vertical channel layer 2 and the upper surface of the horizontal channel layer 1 adjacent thereto; the thickness of the vertical end of the first dielectric layer 4 is greater than the thickness of the vertical end of the second dielectric layer 4.
[0038] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the gate 5 includes a sensing gate 501, a tunneling gate 502, and a control gate 503. The sensing gate 501 is fixedly disposed on the side of the first dielectric layer 4 away from the vertical channel layer 2. The control gate 503 is fixedly disposed on the side of the second dielectric layer 4 away from the horizontal channel layer 1 at the horizontal end. The tunneling gate 502 is vertically fixedly disposed on the side of the control gate 503 away from the second dielectric layer 4. The tunneling gate 502 is parallel to the vertical end of the second dielectric layer 4. A biocavity 7 is formed between the tunneling gate 502 and the second dielectric layer 4. The biocavity 7 is obtained by etching the second dielectric layer 4 using RIE technology. The biocavity 7 is filled with biomolecules.
[0039] According to the present invention, a vertical biosensor based on an undoped tunneling field-effect transistor is provided: the electrode includes a source 601 and a drain 602, the source 601 is fixedly disposed on one side wall of the horizontal channel layer 1 near the sensing gate 501, and the drain 602 is fixedly disposed on one side wall of the horizontal channel layer 1 near the control gate 503.
[0040] This invention is based on an improvement of the fin-type electron-hole double-layer TFET (HBF-EHBTFET) device. The main material of the channel layer is a narrow-bandgap direct tunneling semiconductor material (InGaAs), which improves the electron tunneling rate in the device, reduces device heat generation, thereby increasing the on-state current and switching current ratio of the device and reducing the change in the dielectric constant of biomolecules in the biological cavity 7 caused by heat generation, thus improving the stability of device detection.
[0041] Furthermore, based on the principle of charged plasma, the electron and hole layers of the finned channel can be induced by selecting metals with different work functions. Since the dielectric constants of the filling biomolecules differ, the ability of the tunneling gate 502 to sense charges also changes, improving the sensor's sensitivity to detect different biomolecules.
[0042] The introduction of vertical nanocavities allows more biomolecules to enter the nano-biocavities under the influence of gravity, thereby further improving the sensitivity of the sensor.
[0043] To reduce off-state leakage caused by tunneling between the bottom channel region and drain 602, a metal Ru with a work function of 4.7 eV was selected as the control gate 503, and In was introduced into the bottom channel.0.52 Al 0.48 As a barrier layer 3 extending upwards, it avoids traps caused by lattice mismatch while maximally shielding direct tunneling between the source and drain.
[0044] The combination of the two can significantly reduce the device's off-state current and SS. avg This enhances the device's average subthreshold swing sensitivity (S0). SSavg ).
[0045] To reduce the impact of gate leakage on sensitivity and enhance the integration of biomolecules with the nanocavity, the thickness of HfO2 inside the cavity was set to 2.5 nm.
[0046] To avoid random doping fluctuations and reduce complex thermal budgets and process difficulties, this invention uses platinum and hafnium metals to sense the source and drain regions of the sensor, respectively, and uses them as source electrode 601 and drain electrode 602 metals.
[0047] The fabrication process of a vertical biosensor based on an undoped tunneling field-effect transistor provided by this invention is as follows:
[0048] S1: Undoped In is grown on an InP substrate using molecular beam epitaxy (MBE). 0.53 Ga 0.47 The channel layer serves as the main material of the sensor;
[0049] S2: Using reactive ion etching (RIE) to process In 0.53 Ga 0.47 The bottom of the As channel layer is etched to create a U-shaped groove, and then In is grown in the U-shaped groove using MBE technology. 0.52 Al 0.48 As the barrier layer 3;
[0050] S3: In is grown on both sides and above the barrier layer 3 using MBE technology. 0.53 Ga 0.47 As the vertical channel layer 2 serves as the fin channel, and then a 2 nm thick HfO2 dielectric layer 4 is deposited on both sides of the fin channel using atomic layer deposition (ALD) technology.
[0051] S4: The positions of source electrode 6 and drain electrode 6 are etched on the left and right sides using RIE etching technology, and Pt and Hf are deposited as source electrode 6 and drain electrode 6 respectively using ALD technology.
[0052] S5: An HfO2 dielectric layer is deposited using ALD technology until it is flush with the fin channel;
[0053] S6: Two U-shaped grooves of the same width are etched in the dielectric layer 4 on both sides of the fin using RIE technology. Then, horizontal sensing gate 501 and control gate 503 are deposited in the left and right U-shaped grooves respectively using ALD deposition technology.
[0054] S7: HfO2 is deposited in two U-shaped grooves using ALD deposition technology until it is flush with the fin-shaped channel. Then, two U-shaped grooves are etched using RIE technology, and vertical induction gate 501 and tunneling gate 502 are deposited in the left and right U-shaped grooves respectively.
[0055] S8: Using RIE technology, a U-shaped groove is etched in the dielectric layer 4 on the left side of the tunneling gate 502 as a biological cavity 7 to be filled with biomolecules.
[0056] Due to its unique tunneling mechanism (based on electron-hole double layer in the channel to achieve line tunneling (LT)) and suitable materials, it can achieve higher Ig with a smaller bias. on and smaller SS avg This enhances the on-state current sensitivity (S) of the device. Ion Threshold voltage sensitivity (S) Vth ) and average subthreshold swing sensitivity (S SSavg This also reduces the power consumption of the device.
[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A vertical biosensor based on an undoped tunneling field effect transistor, characterized in that, include: Horizontal channel layer (1); A vertical channel layer (2) is vertically fixed at the middle position on the surface of the horizontal channel layer (1), and a U-shaped groove is provided at the bottom end of the vertical channel layer (2) corresponding to the horizontal channel layer (1). The barrier layer (3) is embedded in the U-shaped groove; The dielectric layer (4) includes a first dielectric layer and a second dielectric layer. The first dielectric layer and the second dielectric layer are L-shaped structures. The first dielectric layer and the second dielectric layer are respectively fixedly disposed on adjacent surfaces on both sides of the horizontal channel layer (1) and the vertical channel layer (2). The gate (5) is fixedly disposed on the side of the dielectric layer (4) away from the horizontal channel layer (1) and the vertical channel layer (2); Electrodes (6) are fixedly disposed on both sides of the horizontal channel layer (1).
2. The vertical biosensor based on undoped tunneling field effect transistor according to claim 1, characterized in that: The horizontal channel layer (1) and the vertical channel layer (2) are fin-shaped channel layers, and the material of the horizontal channel layer (1) and the vertical channel layer (2) is In. 0.53 Ga 0.47 As.
3. The vertical biosensor based on undoped tunneling field effect transistor according to claim 1, wherein: The material of the barrier layer (3) is In 0.52 Al 0.48 As.
4. The vertical biosensor based on undoped tunneling field effect transistor according to claim 1, wherein: The first medium layer is fixedly disposed on the left side of the vertical channel layer (2) and the upper surface of the horizontal channel layer (1) adjacent to it. The second medium layer is fixedly disposed on the right side of the vertical channel layer (2) and the upper surface of the horizontal channel layer (1) adjacent to it. The thickness of the vertical end of the first medium layer is greater than the thickness of the vertical end of the second medium layer.
5. The vertical biosensor based on undoped tunneling field effect transistor according to claim 4, characterized in that: The gate (5) includes a sensing gate (501), a tunneling gate (502) and a control gate (503). The sensing gate (501) is fixedly disposed on the side of the first dielectric layer away from the vertical channel layer (2). The control gate (503) is fixedly disposed on the side of the second dielectric layer away from the horizontal channel layer (1) at the horizontal end. The tunneling gate (502) is vertically fixedly disposed on the side of the control gate (503) away from the second dielectric layer. The tunneling gate (502) is parallel to the vertical end of the second dielectric layer. A biological cavity (7) is formed between the tunneling gate (502) and the second dielectric layer.
6. The vertical biosensor based on undoped tunneling field effect transistor according to claim 5, characterized in that: The electrode includes a source (601) and a drain (602). The source (601) is fixedly disposed on one side wall of the horizontal channel layer (1) near the sensing gate (501), and the drain (602) is fixedly disposed on one side wall of the horizontal channel layer (1) near the control gate (503).