A dual-sensing segment mos-hemt biosensor

Abstract

This invention proposes a dual-sensor MOS-HEMT biosensor, comprising: a substrate, and a GaN buffer layer, a GaN channel layer, an AlN spacer layer, and a barrier layer sequentially stacked on the substrate; wherein, the upper surface of the barrier layer is provided with multiple source electrodes, multiple gate structures, and a drain electrode, and the gate structures are spaced apart; each gate structure includes a gate oxide layer and a gate, the gate oxide layer and the gate are sequentially stacked from bottom to top, and the horizontal length of the gate is greater than the horizontal length of the gate oxide layer; at least one cavity region is provided on both sides of each gate oxide layer, the cavity region serving as a sensing region. This dual-sensor sensor effectively increases the sensing area and significantly improves the device's sensing sensitivity to neutral and charged biomolecules.

Description

Technical Field

[0001] This invention relates to the field of semiconductor sensor technology, and more particularly to a dual-sensor segment MOS-HEMT biosensor. Background Technology

[0002] GaN-based high electron mobility transistors (HEMTs) have important applications in high-temperature, high-frequency, and high-power electronic devices due to their inherent advantages such as wide bandgap, high 2DEG concentration, high breakdown field, and high electron saturation velocity. The 2DEG concentration in GaN-based HEMT heterojunctions is particularly high. Furthermore, it is highly dependent on the surface state of the device; any minute change in the external environment can lead to a change in the 2DEG concentration, resulting in a significant change in the output current between the source and drain. This can solve the problems of traditional sensors being insensitive to weak targets and having insignificant signal changes. Gallium nitride (GaN) materials have good biocompatibility, chemical resistance, and high-temperature resistance. Therefore, GaN-based HEMTs are not only well-suited for chemical and biological sensors, but also offer advantages such as high sensitivity, fast response speed, high reliability, small size, and easy integration with traditional FETs.

[0003] GaN-based HEMT sensors are primarily designed for the detection of charged biomolecules. This is achieved by introducing a barrier layer between the gate metal and the barrier layer. Using oxides to construct metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) structures can further optimize device interface characteristics and enable the sensing and detection of neutral and charged biomolecules. However, to date, most AlGaN / GaN MOS-HEMT biosensors employ device structures with a single sensing segment. Limited by the single-sense-segment design, the devices have limited ability to capture weak biomolecule signals, resulting in low overall detection sensitivity. This makes it difficult to meet the application requirements of high-precision biosensing and hinders further improvements in device performance. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a dual-sensor segment MOS-HEMT biosensor, aiming to solve the problem of relatively low sensitivity in traditional single-sensor segment devices.

[0005] This invention provides a dual-sensing-segment MOS-HEMT biosensor, comprising: A substrate, and a GaN buffer layer, a GaN channel layer, an AlN spacer layer and a barrier layer sequentially stacked on the substrate; The upper surface of the barrier layer is provided with multiple sources, multiple gate structures and drains, and the gate structures are arranged at intervals. Each of the gate structures includes a gate oxide layer and a gate, which are stacked sequentially from bottom to top, and the length of the gate in the horizontal direction is greater than the length of the gate oxide layer in the horizontal direction. Each of the gate oxide layers has at least one cavity region on both sides, and the cavity region serves as a sensing region.

[0006] In one embodiment of the present invention, the number of gate structures is two, including a first gate structure and a second gate structure. The first gate structure includes a first gate and a first gate oxide layer, and the second gate structure includes a second gate and a second gate oxide layer. The upper surface of the barrier layer is provided with a first source, a first gate oxide layer, a drain, a second gate oxide layer, and a second source in sequence. In this configuration, a first gate is disposed above the first gate oxide layer, and a second gate is disposed above the second gate oxide layer.

[0007] In one embodiment of the present invention, a first cavity region and a second cavity region are respectively provided on both sides of the first gate oxide layer; A third cavity region and a fourth cavity region are respectively provided on both sides of the second gate oxide layer.

[0008] In one embodiment of the present invention, the first source, the first gate oxide layer, the drain, the second gate oxide layer, and the second source are arranged sequentially and spaced apart in the horizontal direction on the upper surface of the barrier layer to form an interdigitated electrode structure, such that the first gate structure and the second gate structure are connected in parallel between the first source, the second source, and the drain.

[0009] In one embodiment of the present invention, the substrate is made of any one of Si, sapphire, or SiC.

[0010] In one embodiment of the present invention, the thickness of the GaN buffer layer ranges from 1 μm to 2 μm; the thickness of the GaN channel layer ranges from 15 nm to 100 nm; and the thickness of the AlN spacer layer ranges from 0.5 nm to 3 nm.

[0011] In one embodiment of the present invention, the barrier layer is made of AlGaN, with a thickness ranging from 15 nm to 30 nm and an Al composition of 0.1 to 0.25.

[0012] In one embodiment of the present invention, the material of the gate oxide layer is Any one of them, with a thickness ranging from 10nm to 30nm; The length of the gate along the horizontal direction ranges from 1 μm to 5 μm.

[0013] In one embodiment of the present invention, the source is an ohmic contact, the drain is an ohmic contact, and the gate is a Schottky contact.

[0014] In one embodiment of the present invention, the length of the cavity region in the horizontal direction ranges from 0.1 μm to 2 μm.

[0015] As can be seen from the above solutions, the advantages of the present invention are: The dual-sensor GaN-based MOS-HEMT biosensor provided by this invention features multiple gate structures disposed on the surface of the barrier layer. These gate structures are spaced apart to form multiple sensing segments, effectively increasing the sensing area. The horizontal length of the gate in each gate structure is greater than the length of the gate oxide layer, resulting in a larger coverage area of ​​the channel region below and enhanced gate control capability. Furthermore, at least one cavity region is provided on both sides of each gate oxide layer as a sensing region, ensuring that the sensing region is adjacent to the gate control channel, effectively increasing the sensing area and achieving high-sensitivity detection of neutral and charged biomolecules. This sensor structure employs an interdigitated electrode design, essentially connecting individual discrete sensors in parallel, significantly reducing the distance between electrodes and channel resistance, thereby enhancing device control. This design not only improves sensing sensitivity but also ensures the reliability and stability of the sensor. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the dual-sensing-segment MOS-HEMT biosensor of the present invention; Figure 2 This is a schematic diagram of the structure of a single-sensor segment MOS-HEMT biosensor, in which... Figure 2 (a) The gate length and cavity length of the device are the same as those of the dual-sensor segment device. Figure 2 (b) The gate length and cavity length of the device are both twice that of the dual-sensor segment device; Figure 3 This is a comparison chart of the output characteristic curves of single-sensor segment and dual-sensor segment sensors; Figure 4 It is a comparison chart of the transconductance curves of single-sensor segment and dual-sensor segment sensors; Figure 5 This is a comparison of the induced current of single-sensor and dual-sensor sensors when 3-aminopropyltriethoxysilane biomolecules are added to the cavity region.

[0017] The attached figures are labeled as follows: 1-Substrate, 2-GaN buffer layer, 3-GaN channel layer, 4-AlN spacer layer, 5-Barrier layer; 6-Source, 61-First source, 62-Second source; 7-Gate structure, 71-Gate oxide layer, 72-Gate, 711-First gate oxide layer, 712-Second gate oxide layer, 721-First gate, 722-Second gate; 8-Drain; 9-Cavity region, 91-First cavity region, 92-Second cavity region, 93-Third cavity region, 94-Fourth cavity region. Detailed Implementation

[0018] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0019] In the absence of further restrictions, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] refer to Figure 1 As shown, Figure 1 A schematic diagram of the structure of a dual-sensor segment MOS-HEMT biosensor provided in one embodiment is shown.

[0021] A dual-sensor MOS-HEMT biosensor includes a substrate 1, a GaN buffer layer 2, a GaN channel layer 3, an AlN spacer layer 4, and a barrier layer 5. The substrate 1, GaN buffer layer 2, GaN channel layer 3, AlN spacer layer 4, and barrier layer 5 are sequentially stacked, with the substrate 1 at the bottom. The upper surface of the barrier layer 5 has multiple sources 6, multiple gate structures 7, and drains 8. The gate structures 7 are spaced apart along the upper surface of the barrier layer 5, forming multiple sensing segments and effectively increasing the sensing area.

[0022] Each of the gate structures 7 includes a gate oxide layer 71 and a gate 72, which are stacked sequentially from bottom to top, with the gate oxide layer 71 located at the bottom layer. Preferably, the horizontal length of the gate 72 is greater than the horizontal length of the gate oxide layer 71, so that the gate covers a larger area of ​​the channel region below, thereby enhancing the gate control capability.

[0023] Each of the gate oxide layers 71 has at least one cavity region 9 on both sides, which serves as a sensing region. The sensing regions are located on both sides of the gate oxide layer, such that the sensing regions are adjacent to the gate control channel.

[0024] This invention achieves a doubling of the sensing area and a reduction of the channel resistance by arranging multiple gate structures at intervals and setting cavity regions on both sides of the gate oxide layer, effectively solving the technical problems of limited ability of traditional single-sensor segment sensors to capture weak biomolecular signals and low detection sensitivity.

[0025] Further reference Figure 1 As shown, in one specific implementation, there are two gate structures 7, including a first gate structure and a second gate structure. The first gate structure includes a first gate 721 and a first gate oxide layer 711, and the second gate structure includes a second gate 722 and a second gate oxide layer 712. The source 6 includes a first source 61 and a second source 62. The upper surface of the barrier layer 5 is sequentially provided with a first source 61, a first gate oxide layer 711, a drain 8, a second gate oxide layer 712, and a second source 62. Preferably, the first source 61, the first gate oxide layer 711, the drain 8, the second gate oxide layer 712, and the second source 62 are arranged sequentially and alternately in the horizontal direction on the upper surface of the barrier layer 5 to form an interpolated electrode structure, such that the first gate structure and the second gate structure are connected in parallel between the first source 61, the second source 62, and the drain 8, forming a symmetrical "source-gate-drain-gate-source" arrangement. The two gate structures share a drain in the middle, and a source is provided on each of the left and right sides, resulting in a compact structure and symmetrical layout.

[0026] The first gate 721 is disposed above the first gate oxide layer 711, and the second gate 722 is disposed above the second gate oxide layer 712. The length of the gate along the horizontal direction is greater than the length of the gate oxide layer along the horizontal direction. The two gates independently control the channel region below them. At the same time, the gates extend beyond the gate oxide layer, which enhances the ability to control the two-dimensional electron gas in the channel below the cavity sensing region on both sides of the gate oxide layer.

[0027] Further reference Figure 1 As shown, in one specific implementation, a first cavity region 91 and a second cavity region 92 are respectively provided on both sides of the first gate oxide layer 711, and a third cavity region 93 and a fourth cavity region 94 are respectively provided on both sides of the second gate oxide layer 712. Sensing regions are formed on both sides of each gate oxide layer, so that a single gate structure corresponds to two sensing regions, effectively utilizing the space on both sides of the gate and expanding the sensing area without increasing the lateral size of the device.

[0028] In one embodiment, the substrate 1 is made of any one of Si, sapphire, or SiC.

[0029] The thickness of the GaN buffer layer 2 ranges from 1 μm to 2 μm; the thickness of the GaN channel layer 3 ranges from 15 nm to 100 nm; and the thickness of the AlN spacer layer 4 ranges from 0.5 nm to 3 nm.

[0030] The barrier layer 5 is made of AlGaN, with a thickness ranging from 15 nm to 30 nm and an Al composition of 0.1 to 0.25.

[0031] The material of the gate oxide layer 71 is Any one of them, with a thickness ranging from 10 nm to 30 nm. The gate 72 has a horizontal length ranging from 1 μm to 5 μm, and the horizontal length of the gate is greater than the horizontal length of the gate oxide layer.

[0032] The source electrode is an ohmic contact, the drain electrode is an ohmic contact, and the gate electrode is a Schottky contact.

[0033] The length of the cavity region in the horizontal direction ranges from 0.1 μm to 2 μm.

[0034] To verify the advantages of the proposed dual-sensor segment MOS-HEMT biosensor over the single-sensor segment sensor, the performance indicators of the single-sensor segment and dual-sensor segment MOS-HEMT sensors were simulated. Figure 2 This is a schematic diagram of the structure of a single-sensor segment MOS-HEMT biosensor, in which... Figure 2 (a) The gate length and cavity length of the sensor are the same as those of the dual-sensor segment device. Figure 2 (b) The gate length and cavity length of the sensor are both twice that of the dual-sensor segment device. The dual-sensor segment sensor of this invention is defined as device 1. Figure 2 (a) The single-segment sensor is defined as device 2. Figure 2 (b) The single-sensor segment sensor is defined as device 3. As can be seen from the figure, compared with the dual-sensor segment, the single-sensor segment sensor has a single source 6 and a drain 8 on the left and right sides of the upper surface of the barrier layer 5, respectively, and only a single gate structure is provided between the source 6 and the drain 8.

[0035] The performance of a single-sensor MOS-HEMT device and the dual-sensor MOS-HEMT device proposed in this invention were compared using Silvaco TCAD simulation software. To obtain key parameters such as the output and transfer characteristics of the MOS-HEMT, numerical calculations were performed using the Schrödinger equation, Poisson equation, and carrier continuity equation to achieve accurate simulation and analysis of the device performance. The physical models used in the simulation included the polarization model, the Shockley-Read-Hall recombination model, the Fermi-Dirac carrier statistical model, and the low-field mobility model.

[0036] Figure 3 This image shows a comparison of the output characteristic curves of dual-sensor and single-sensor MOS-HEMT devices at a gate-source voltage of 0V. Figure 3 It can be seen that, compared with device 2 which has a single sensing segment, device 3, which has a larger gate length and cavity length, has a smaller output current, while device 1, which has a dual sensing segment, has a larger output current than devices 2 and 3, which both have a single sensing segment.

[0037] Figure 4 A comparison of transconductance curves for dual-sensor and single-sensor MOS-HEMT devices at a drain-source voltage of 7V is shown. According to... Figure 4 It can be seen that the peak transconductance of devices 1, 2, and 3 decreases sequentially. For devices 2 and 3, the output current and peak transconductance of device 3 are smaller than those of device 2, mainly because the increased gate length leads to increased gate resistance, resulting in increased total resistance of the device and weakened gate control capability, thus reducing output current and peak transconductance. For devices 1 and 3, the sensing area lengths of these two devices are the same. According to theoretical analysis, when the sensing area lengths are the same, the resistance of a dual-sensor device is smaller than that of a single-sensor device. This is because the dual-sensor device uses an interdigitated electrode design, which is equivalent to connecting individual discrete sensors in parallel, thereby significantly reducing the distance between electrodes and channel resistance, strengthening the control of the device, and thus increasing the output current and peak transconductance.

[0038] By introducing biomolecules into the cavity region, MOS-HEMT can achieve sensing and detection. When the 3-aminopropyltriethoxysilane biomolecule is added to the cavity region, the sensing current (the absolute value of the change in output current before and after the addition of the biomolecule) of the dual-sensing segment of the proposed invention and the existing single-sensing segment MOS-HEMT biosensor at a drain-source voltage of 10V is as follows: Figure 5 As shown. By Figure 5It is evident that the induced current of dual-sensor device 1 is greater than that of single-sensor devices 2 and 3, while the induced current of device 3 is greater than that of device 2. The larger induced current of the other two devices compared to device 2 is primarily due to their larger sensing areas, which enhance the reaction between biomolecules and the AlGaN functional layer. Although devices 1 and 3 have the same sensing area, the induced current of device 1 is significantly greater than that of device 3. This is because device 1 is a dual-sensor device with interdigitated electrodes, which reduces channel resistance, enhances the device's control capability, and thus improves sensing sensitivity.

[0039] In summary, the dual-sensor GaN-based MOS-HEMT biosensor proposed in this invention effectively increases the sensing area through its dual-sensor GaN-based MOS-HEMT structure, significantly improving the device's sensing sensitivity to neutral and charged biomolecules.

[0040] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A dual-sensing-segment MOS-HEMT biosensor, characterized in that, include: A substrate, and a GaN buffer layer, a GaN channel layer, an AlN spacer layer and a barrier layer sequentially stacked on the substrate; The upper surface of the barrier layer is provided with multiple sources, multiple gate structures and drains, and the gate structures are arranged at intervals. Each of the gate structures includes a gate oxide layer and a gate, which are stacked sequentially from bottom to top, and the length of the gate in the horizontal direction is greater than the length of the gate oxide layer in the horizontal direction. Each of the gate oxide layers has at least one cavity region on both sides, and the cavity region serves as a sensing region.

2. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The number of gate structures is two, including a first gate structure and a second gate structure. The first gate structure includes a first gate and a first gate oxide layer, and the second gate structure includes a second gate and a second gate oxide layer. The upper surface of the barrier layer is provided with a first source, a first gate oxide layer, a drain, a second gate oxide layer, and a second source in sequence. In this configuration, a first gate is disposed above the first gate oxide layer, and a second gate is disposed above the second gate oxide layer.

3. The dual-sensor segment MOS-HEMT biosensor according to claim 2, characterized in that, A first cavity region and a second cavity region are respectively provided on both sides of the first gate oxide layer; A third cavity region and a fourth cavity region are respectively provided on both sides of the second gate oxide layer.

4. The dual-sensor segment MOS-HEMT biosensor according to claim 2, characterized in that, The first source, the first gate oxide layer, the drain, the second gate oxide layer, and the second source are arranged sequentially and spaced apart in the horizontal direction on the upper surface of the barrier layer to form an interdigitated electrode structure, such that the first gate structure and the second gate structure are connected in parallel between the first source, the second source, and the drain.

5. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The substrate is made of any one of Si, sapphire, or SiC.

6. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The thickness of the GaN buffer layer ranges from 1 μm to 2 μm; the thickness of the GaN channel layer ranges from 15 nm to 100 nm; and the thickness of the AlN spacer layer ranges from 0.5 nm to 3 nm.

7. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The barrier layer is made of AlGaN, with a thickness ranging from 15 nm to 30 nm and an Al composition of 0.1 to 0.

25.

8. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The material of the gate oxide layer is , or Any one of them, with a thickness ranging from 10nm to 30nm; The length of the gate along the horizontal direction ranges from 1 μm to 5 μm.

9. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The source electrode is an ohmic contact, the drain electrode is an ohmic contact, and the gate electrode is a Schottky contact.

10. The dual-sensor segment MOS-HEMT biosensor according to claim 1, characterized in that, The length of the cavity region in the horizontal direction ranges from 0.1 μm to 2 μm.

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