Angle sensing device based on huge anisotropic conductance effect and preparation method thereof

Abstract

The invention belongs to the technical field of magnetic sensors, and discloses an angle sensor device based on a huge anisotropic conductance effect and a preparation method thereof, the angle sensor device is formed by combining a substrate, a bismuth palladium nanosheet, a Hall strip channel structure, a gold film metal electrode and hexagonal-boron nitride; the preparation method of the angle sensor comprises the following steps: S1, cleaning the silicon / silicon oxide substrate; s2, bonding the palladium bismuthide nanosheet on the surface of the substrate; s3, manufacturing a Hall strip channel structure on the palladium bismuthide nanosheet; s4, evaporating a gold film metal electrode on the Hall strip channel structure; s5, covering and packaging the palladium bismuthide nanosheet, the Hall strip channel structure and the gold film metal electrode by using hexagonal-boron nitride; the problems that an existing angle sensor is low in sensitivity, poor in stability, insufficient in precision, large in measurement error and not beneficial to miniaturization and integration of equipment due to the large size in a low-temperature strong magnetic field are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic sensors, and particularly to an angle sensor device based on the giant anisotropic magnetoresistance effect and a preparation method thereof. Background Art

[0002] In the era of rapid development of current technology, extremely stringent requirements are put forward for the performance of angle sensors in many high-tech fields. For example, in cutting-edge technology fields such as cryogenic strong magnetic field systems and dilution refrigeration systems, due to many performance limitations of traditional angle sensors, it is difficult to meet their application requirements of high precision, high stability, miniaturization, and integration.

[0003] Currently, common angle sensors often have problems such as decreased sensitivity and poor stability when facing a cryogenic strong magnetic field environment. Their detection accuracy cannot reach the level expected by these high-tech fields. In a magnetic field environment, the measurement error is large, and it is difficult to accurately sense small changes in the angle. Moreover, traditional angle sensors are large in size, which is not conducive to the miniaturization and integrated layout of equipment in complex systems with limited space, restricting the improvement of the overall performance and function expansion of the system. Summary of the Invention

[0004] The present invention aims to provide an angle sensor device based on the giant anisotropic magnetoresistance effect and a preparation method thereof, so as to solve the problems of low sensitivity, poor stability, insufficient accuracy, large measurement error of existing angle sensors under cryogenic strong magnetic fields, and large size which is not conducive to the miniaturization and integration of equipment.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An angle sensor device based on the giant anisotropic magnetoresistance effect, comprising:

[0007] A substrate for providing support for the entire sensor device; palladium bismuthide nanosheets, which are tightly adhered to the surface of the substrate by van der Waals forces, and the palladium bismuthide nanosheets are in a β-phase structure; a Hall bar channel structure formed by spin-coating an electron beam photoresist on the substrate adhered with palladium bismuthide nanosheets, followed by electron beam exposure, development, and fixing processes, and the Hall bar channel structure provides a specific current flow path in the palladium bismuthide nanosheets; gold film metal electrodes evaporated on the Hall bar channel structure by a thermal evaporation process, and the gold film metal electrodes are used to transmit electrical signals generated by anisotropic conductance changes; hexagonal boron nitride for covering and encapsulating the palladium bismuthide nanosheets, the Hall bar channel structure, and the gold film metal electrodes.

[0008] Further, the thickness of the palladium bismuthide nanosheets is 21 - 23 nanometers.

[0009] Further, the substrate is made of silicon / silicon oxide.

[0010] Furthermore, the angular sensor device based on the giant anisotropic conductance effect achieves a 99% giant anisotropic conductance change when the phase difference is 90° under low temperature and strong magnetic field. The sensing range is 0 to 360°, and this conductance change is only related to the magnetic field and the relative direction of the device. The conductance is maximum when the magnetic field is parallel to the sensor plane, showing high sensitivity and high stability.

[0011] Furthermore, the gold film metal electrode has good conductivity and stability, and forms a reliable electrical contact with the Hall bar channel structure to ensure the effective transmission of electrical signals.

[0012] The preparation method of the angular sensor device based on the giant anisotropic conductance effect includes the following steps:

[0013] S1. Clean the substrate. Use silicon or silicon oxide as the substrate, and ultrasonically clean the substrate with deionized water to remove dust particles on the substrate surface. Then ultrasonically clean the substrate with propanol and ethanol in sequence to remove organic pollutants. Finally, dry it with nitrogen to ensure the cleanliness of the substrate surface.

[0014] S2. Bonding of palladium bismuthide nanosheets. Stick the tape to the surface of the palladium bismuthide single crystal, then peel the tape from the surface of the palladium bismuthide single crystal, and bond it to the cleaned substrate through van der Waals force. After uncovering the tape, use an atomic force microscope to screen out palladium bismuthide nanosheets with a thickness of 21 - 23 nanometers.

[0015] S3. Fabricate the Hall bar channel structure. Spin - coat electron beam photoresist on the palladium bismuthide nanosheets, dry the spin - coated substrate, then expose the shape of the Hall bar electrode on the palladium bismuthide nanosheets through electron beam lithography, and then remove the exposed part through development and fixing operations to complete the fabrication of the Hall bar channel structure.

[0016] S4. Evaporate the gold film metal electrode. Evaporate and deposit a gold film metal electrode on the Hall bar channel structure through thermal evaporation, and then soak it in acetone to remove the remaining photoresist, leaving the metal electrode of the Hall structure.

[0017] S5. Cover and encapsulate. Peel off the nanosheets from the surface of hexagonal boron nitride with a polydimethylsiloxane film, and cover the palladium bismuthide nanosheets, Hall bar channel structure and gold film metal electrode with the nanosheets through a two - dimensional material transfer system to achieve encapsulation.

[0018] Furthermore, the palladium bismuthide nanosheets can also be obtained by the cosolvent method combined with the solid - phase exfoliation method to ensure that the palladium bismuthide nanosheets are in the β - phase structure and have good uniformity and quality.

[0019] The beneficial effects of the technical solution are:

[0020] 1. High sensitivity and stability: β-phase palladium bismuthide nanosheets with a thickness of 21 - 23 nanometers are used. When the phase difference is 90° under low temperature and strong magnetic field, a huge anisotropic conductance change of 99% can be achieved. The induction range is 0 - 360°, and the conductance change is only related to the magnetic field and the relative direction of the device. The conductance is maximum when the magnetic field is parallel to the plane of the sensor, greatly improving the sensitivity and stability of the sensor in complex environments, being able to accurately sense tiny changes in angles, and meeting the requirements for high-precision measurement in high-tech fields.

[0021] 2. Optimized structural design: The unique structural design includes palladium bismuthide nanosheets tightly adhered to a silicon or silicon oxide substrate by van der Waals forces, and a Hall bar channel structure and a gold film metal electrode formed on this basis through specific processes, ensuring that the current flows stably along a specific path within the palladium bismuthide nanosheets. The gold film metal electrode is in reliable electrical contact with the Hall bar channel structure, effectively transmitting the electrical signals generated by the anisotropic conductance change, and guaranteeing the reliability and stability of the overall performance of the sensor.

[0022] 3. Effective encapsulation and protection: Covering and encapsulating with hexagonal boron nitride can effectively isolate external interference, protect the internal palladium bismuthide nanosheets, Hall bar channel structure and gold film metal electrode, ensure the stable operation of the sensor in extreme environments such as low temperature and strong magnetic field, and extend its service life.

[0023] 4. Potential for miniaturization and integration: Through a series of advanced preparation processes, such as precisely controlling the size and position of each component by electron beam lithography, it is possible to miniaturize the entire sensor device, which is conducive to integrated layout in complex systems with limited space, improving the overall performance of the system and expanding its functions.

[0024] 5. Diversity of preparation methods and quality controllability: Palladium bismuthide nanosheets can be obtained either by tape peeling and screening method or by a method combining a cosolvent method and solid-phase exfoliation method, ensuring that it is in the β-phase structure and has good uniformity and quality, providing a reliable guarantee for the preparation of high-performance angle sensor devices. At the same time, the diverse preparation methods also increase the flexibility and controllability of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the angle sensor device prepared in Embodiment 1 of the present invention;

[0026] Figure 2 It is an exploded structural diagram of the angle sensor device prepared in Embodiment 1 of the present invention;

[0027] Figure 3 It is a physical diagram of the angle sensor device prepared in Embodiment 1 of the present invention;

[0028] Figure 4It is the output characteristic diagram of the magnetoresistance test in Embodiment 2 of the present invention;

[0029] The names of the corresponding marks in the drawings are: substrate 1, palladium bismuthide nanosheet 2, Hall bar channel structure 3, gold film metal electrode 4, hexagonal boron nitride 5. Detailed implementation manners

[0030] The present invention will be further described in detail below with reference to the drawings and embodiments:

[0031] Preparation of the angle sensor device in Embodiment 1

[0032] 1.1 Preparation of β-phase palladium bismuthide nanosheets

[0033] Prepare β-phase palladium bismuthide single crystals by the cosolvent method. Stick the tape to the surface of the palladium bismuthide single crystal, and then peel the tape from the surface of the palladium bismuthide single crystal. Part of the palladium bismuthide material will adhere to the tape. Stick the tape to the cleaned silicon / silicon oxide substrate, and after uncovering the tape, use an atomic force microscope to screen out β-phase palladium bismuthide nanosheets with a thickness of 22 nanometers.

[0034] 1.2 Preparation of gold film metal electrodes

[0035] Place the prepared substrate with β-phase palladium bismuthide nanosheets on the sample stage of the electron beam exposure equipment. Use the electron beam exposure process to define the pattern of the conductive microelectrodes on the nanosheets. Subsequently, through the metal evaporation method, deposit gold thin film materials in the patterned area to form conductive microelectrodes. Remove the excess metal through the etching process to accurately obtain the required conductive microelectrode structure.

[0036] 1.3 Encapsulation

[0037] Select a hexagonal boron nitride thin sheet with an appropriate thickness, and cover the β-phase palladium bismuthide nanosheets with the prepared conductive microelectrodes through a two-dimensional material transfer system to complete the encapsulation process. The encapsulation process needs to be carried out in a clean environment to avoid introducing impurities that affect the performance of the sensor.

[0038] 1.4 Performance testing and calibration: Place the encapsulated angle sensor device in a low-temperature strong magnetic field test system, measure its conductance changes under different magnetic field directions and intensities, and verify its anisotropic conductance effect. Under the system conditions of a magnetic field of 14T and a temperature of 2K, when the initial angle is 0°, it represents that the magnetic field is perpendicular to the sensor plane. Slowly rotate the sensor to change the angle between the magnetic field and the sensor plane, and at the same time measure the conductivity of the sensor at different angles through the metal microelectrodes, so as to realize the measurement of the conductance in the full angle range of 0 to 360°. Calibrate the sensor according to the measurement results to ensure its measurement accuracy in the induction range of 0 to 360°, so that it meets the application requirements in fields such as low-temperature strong magnetic field systems and dilution refrigeration systems.

[0039] After detection, as Figure 3 shown, the physical size of the sensor is in the order of dozens of micrometers, which meets the requirements of miniaturization and integration of the sensor. According to the measurement results, the sensor is calibrated to ensure its measurement accuracy and stability within the induction range of 0 to 360°, so as to meet the application requirements in fields such as cryogenic strong magnetic field systems and dilution refrigeration systems;

[0040] As Figure 4 shown, under the conditions of extremely low temperature of 2K and strong magnetic field of 14T, when the angle slowly increases from 0° but is less than 70°, the conductance of the sensor changes slowly. When θ approaches 90°, the magnetic field is parallel to the sensor plane and the current direction, and at this time the conductivity increases sharply and reaches the maximum conductance at 90°. The conductance change rate is:

[0041]

[0042] , up to 97%. The test results ensure the high sensitivity of the sensor under cryogenic strong magnetic field conditions.

[0043] The above are only embodiments of the present invention, and common general technical solutions or characteristics in the solution are not described in detail here. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can still be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. An angle sensor device based on giant anisotropic conductivity effect, characterized in that: include: A substrate, used to provide support for the entire sensor device; Bismuth palladium nanosheets, the bismuth palladium nanosheets are tightly bonded to the substrate surface through van der Waals forces, and the bismuth palladium nanosheets are β-phase structures; The Hall bar channel structure is formed by spin coating an electron beam photoresist on a substrate with a bismuth palladium nanosheet, and then undergoing electron beam exposure, development and fixing processes. The Hall bar channel structure provides a specific flow path for current in the bismuth palladium nanosheet; Gold film metal electrode, which is deposited on the Hall bar channel structure by thermal evaporation process, and is used to transmit electrical signals generated by anisotropic conductivity changes; Hexagonal boron nitride is used to cover and encapsulate bismuthized palladium nanosheets, Hall bar channel structures and gold film metal electrodes.

2. The angle sensor device based on giant anisotropic conductivity effect according to claim 1, characterized in that: The thickness of the palladium bismuth nanosheets is 21 to 23 nanometers.

3. The angle sensor device based on giant anisotropic conductivity effect according to claim 1, characterized in that: The substrate is made of silicon / silicon oxide.

4. The angle sensor device based on giant anisotropic conductivity effect according to claim 1, characterized in that: The angle sensor device based on the giant anisotropic conductivity effect achieves a giant anisotropic conductivity change of 99% when the phase difference is 90° under low temperature and strong magnetic field. The sensing range is 0-360°, and the conductivity change is only related to the relative direction of the magnetic field and the device. The conductivity is maximum when the magnetic field is parallel to the plane direction of the sensor, showing high sensitivity and high stability.

5. The angle sensor device based on giant anisotropic conductivity effect according to claim 1, characterized in that: The gold film metal electrode has good conductivity and stability, and forms a reliable electrical contact with the Hall bar channel structure to ensure the effective transmission of electrical signals.

6. The method for preparing an angle sensor device based on giant anisotropic conductivity effect according to claims 1-5, characterized in that: The following steps are involved: S1. Clean the substrate. Use silicon / silicon oxide as the substrate and use deionized water to ultrasonically clean the substrate to remove dust particles on the surface of the substrate. Then use propanol and ethanol to ultrasonically clean the substrate in sequence to remove organic pollutants. Finally, blow dry with nitrogen to ensure that the substrate surface is clean. S2, bonding of palladium bismuth nanosheets, attaching a tape to the surface of the palladium bismuth single crystal, then peeling the tape off the surface of the palladium bismuth single crystal, and then bonding it to a cleaned substrate through van der Waals force, and after peeling off the tape, using an atomic force microscope to screen out palladium bismuth nanosheets with a thickness of 21 to 23 nanometers; S3, manufacturing a Hall bar channel structure, spin-coating an electron beam photoresist on a substrate with a bismuth palladium nanosheet, drying the spin-coated substrate, and then exposing a Hall bar electrode shape on the bismuth palladium nanosheet through an electron beam exposure process, and then removing the exposed part through development and fixing operations to complete the manufacturing of the Hall bar channel structure; S4, evaporating a gold film metal electrode, evaporating a gold film metal electrode on the Hall bar channel structure through a thermal evaporation process, and then soaking in acetone to remove the remaining photoresist, leaving the metal electrode of the Hall structure; S5. Covering and packaging: Use polydimethylsiloxane film to peel off the nanosheets from the hexagonal-boron nitride surface, and cover the nanosheets on the bismuth palladium nanosheets, Hall bar channel structure and gold film metal electrodes through a two-dimensional material transfer system to achieve packaging.

7. The method for preparing an angle sensor device based on giant anisotropic conductivity effect according to claim 6, characterized in that: The bismuth palladium nanosheets can also be obtained by a solvent co-solvent method combined with a solid phase exfoliation method to ensure that the bismuth palladium nanosheets are of a β-phase structure and have good uniformity and quality.

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