Angle sensing device based on room temperature plane Hall effect and preparation method thereof

Abstract

The invention belongs to the technical field of sensors, and discloses an angle sensor based on a room temperature plane Hall effect and a preparation method thereof. According to the sensor, silicon / silicon oxide serves as a substrate, a functional layer is a rhodium bismuthide nanosheet with the thickness of 18 nanometers, hexagonal-boron nitride packaging is adopted, a conductive microelectrode is prepared through an electron beam exposure technology, and the overall size is in the hundred-micron level. The double-angle sine and cosine waveform resistivity signal output with the phase difference of 45 degrees can be realized under a room-temperature strong magnetic field, the induction range is 0-360 degrees, and the signal is unique and stable. The preparation process comprises the steps of substrate cleaning, nanosheet transferring and screening, Hall electrode preparation, metal electrode forming and packaging and the like. The sensor has the characteristics of miniaturization and high performance, is suitable for the fields of communication, sensing, storage and the like, and shows remarkable application advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to an angle sensor device based on the room-temperature planar Hall effect and a preparation method thereof. Background Art

[0002] With the development of the times, miniaturized, integrated and high-performance sensors play an important role in high-tech fields. Especially in the fields of communication, sensing, storage, etc., the requirements for the accuracy, stability and size of angle sensors are extremely stringent.

[0003] Traditional angle sensors have many limitations. For example, some sensors require specific temperature conditions to ensure their performance and cannot work efficiently at room temperature; some sensors have a relatively narrow sensing range and cannot achieve full-angle sensing of 0-360°, making it difficult to meet diverse requirements; moreover, in terms of stability and uniqueness, traditional sensors are also difficult to ensure that accurate and reliable signals are always provided at a certain angle.

[0004] Therefore, the present invention proposes an angle sensor device based on the room-temperature planar Hall effect and a preparation method thereof to solve the above problems. Summary of the Invention

[0005] The present invention aims to provide an angle sensor device based on the room-temperature planar Hall effect and a preparation method thereof. The device of the present invention innovatively selects a 18-nanometer-thick rhodium bismuthide (RhBi 2 ) nanosheet as the functional layer. This material has excellent electrical properties, laying a foundation for the high-performance operation of the sensor. At the same time, an electron beam lithography process is used to prepare conductive microelectrodes, realizing the output of a double-angle sine-cosine waveform resistivity signal with a phase difference of 45° under a room-temperature strong magnetic field. The sensing range covers 0-360°, ensuring the uniqueness and high stability of the angle. Moreover, the overall size of the sensor is in the order of hundreds of micrometers, meeting the requirements of miniaturization and integration, and showing great application prospects in many high-tech fields.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An angle sensor device based on the room-temperature planar Hall effect, which uses silicon / silicon oxide as the substrate, a 18-nanometer-thick rhodium bismuthide nanosheet as the functional layer, is covered and encapsulated with hexagonal boron nitride, and conductive microelectrodes are prepared by an electron beam lithography process. The overall size of the device is in the order of hundreds of micrometers. The sensor device can realize a double-angle sine-cosine waveform resistivity signal with a phase difference of 45° under a room-temperature strong magnetic field, and within the range of 0-360°, the signal has uniqueness and high stability.

[0008] Furthermore, the device is applied to high-tech fields such as communication, sensing, and storage.

[0009] A method for preparing an angle sensor device based on the room-temperature planar Hall effect, comprising the following steps:

[0010] S1. Clean the silicon / silicon oxide substrate;

[0011] S2. Stick the tape onto the surface of the rhodium bismuthide single crystal, and then peel the tape from the surface of the rhodium bismuthide single crystal. The tape will adhere to part of the rhodium bismuthide material. Stick the tape onto the substrate cleaned in step S1, and after uncovering the tape, use an atomic force microscope to screen out nanosheets with a thickness of 18 nanometers;

[0012] S3. Spin-coat an electron beam photoresist on the substrate in step S2. After drying the resist, expose the shape of the Hall bar electrodes on the rhodium bismuthide nanosheets through the electron beam exposure process, and remove the exposed part through the development and fixing operations to achieve the Hall bar channel structure;

[0013] S4. Evaporate a gold film through the thermal evaporation process to cover the device in step S3, soak it in acetone to remove the remaining photoresist, and retain the metal electrodes of the Hall structure to achieve the transfer of the Hall bar pattern;

[0014] S5. Use a polydimethylsiloxane film to peel off the nanosheets from the surface of the hexagonal boron nitride, and cover the device in step S4 through a two-dimensional material transfer system to complete the encapsulation.

[0015] Furthermore, the cleaning process in step S1 is as follows: ultrasonically clean with deionized water to remove surface dust particles, then ultrasonically clean with propanol and ethanol in sequence to remove organic pollutants, and finally blow dry with nitrogen to ensure the cleanliness of the substrate surface.

[0016] The beneficial effects of the technical solution are: The present invention is an angle sensor device based on the room-temperature planar Hall effect, and its key layer is a rhodium bismuthide (RhBi 2 ) nanosheet with a thickness of 18 nanometers. Due to its unique crystal structure and electronic properties, the rhodium bismuthide nanosheet has excellent electrical properties, laying a foundation for the high-performance operation of the device; the device is covered and encapsulated with hexagonal boron nitride, which can effectively protect the functional layer and improve the stability and reliability of the sensor. The conductive microelectrodes are prepared by the electron beam exposure process to achieve precise regulation of the device.

[0017] The sensor of the present invention can operate at room temperature of 300K and in a strong magnetic field environment of 14T, realizing the output of resistivity signals of double-angle sine and cosine waveforms with a phase difference of 45°; its sensing range covers the full angle of 0-360°, breaking through the limitation of the sensing range of traditional angle sensors, and can ensure the uniqueness and high stability of signals at any angle, greatly improving the accuracy and reliability of angle measurement; moreover, the overall size of the sensor of the present invention is in the order of hundreds of micrometers, meeting the requirements of miniaturization and integration, being convenient for integrated application in various complex systems, and showing great application potential in high-tech fields such as communication, sensing, and storage.

[0018] The preparation process of the device of the present invention innovatively combines specific materials with advanced processes, solves the limitations of traditional angle sensors in application scenarios and performance, and opens up a new path for the development of angle sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a top view schematic diagram of the sensor of the present invention;

[0020] Figure 2 is a side view cross-sectional diagram of the sensor of the present invention;

[0021] Figure 3 is a top view of the physical object of the sensor of the present invention;

[0022] Figure 4 is the output characteristic diagram of the sensor of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described in detail below with reference to the drawings and embodiments:

[0024] As Figures 1 - 3 shown, it is a structural schematic diagram of an angle sensor device based on the room-temperature planar Hall effect of the present invention. As Figure 1 shown is a top view schematic diagram of the sensor. As Figure 2 shown is a cross-sectional schematic diagram of the sensor. As Figure 3 shown is a top view of the physical object of the sensor.

[0025] A preparation method of an angle sensor device based on the room-temperature planar Hall effect includes the following steps:

[0026] 1. Prepare materials and instruments: Prepare a silicon / silicon oxide substrate, which serves as the basic support structure for the entire sensor device. At the same time, prepare instruments and equipment such as rhodium dibismuth single crystal, hexagonal boron nitride material, electron beam exposure equipment, thermal evaporation equipment, and two-dimensional material transfer system.

[0027] 2. Substrate cleaning: Clean the silicon / silicon oxide substrate. Use deionized water for ultrasonic cleaning to remove surface dust particles; then use acetone and acetic acid for ultrasonic cleaning in sequence to remove organic pollutants; finally, dry it with nitrogen to ensure the cleanliness of the substrate surface and provide a good foundation for subsequent operations.

[0028] 3. Obtain rhodium dibismuthide nanosheets: Stick the tape tightly to the surface of the rhodium dibismuthide single crystal, and then carefully peel it off from the single crystal surface. At this time, part of the rhodium dibismuthide material will adhere to the tape. Then stick the tape to the cleaned silicon / silicon oxide substrate, and slowly peel off the tape. The rhodium dibismuthide material will be transferred to the substrate. Use an atomic force microscope to scan the transferred material, and accurately screen out rhodium dibismuthide nanosheets with a thickness of about 18 nanometers. This nanosheet will be used as the functional layer of the sensor.

[0029] 4. Fabricate Hall bar electrodes: Spin-coat electron beam photoresist uniformly on the substrate containing the selected rhodium dibismuthide nanosheets. Put the coated substrate into an oven and dry it at an appropriate temperature to cure the photoresist. Use an electron beam exposure device to expose the rhodium dibismuthide nanosheets according to the pre-designed shape of the Hall bar electrodes. After the exposure is completed, perform a developing operation with a developer to remove the exposed part of the photoresist, and then fix it with a fixing solution to achieve the Hall bar channel structure.

[0030] 5. Form metal electrodes: Use the thermal evaporation process to evaporate a gold film on the device with the Hall bar channel structure, so that the gold film uniformly covers the device. Immerse the device with the evaporated gold film in an acetone solution. Since acetone can dissolve the uncured photoresist, after soaking for a period of time, the remaining photoresist is removed, and the metal electrodes of the Hall structure are retained, completing the transfer of the Hall bar pattern.

[0031] 6. Encapsulation: Use a polydimethylsiloxane film to peel off nanosheets from the surface of hexagonal boron nitride. With the help of a two-dimensional material transfer system, accurately cover the peeled hexagonal boron nitride nanosheets on the device with the fabricated metal electrodes to complete the encapsulation of the sensor device and improve the stability and anti-interference ability of the sensor.

[0032] Perform performance tests on the fabricated angle sensor. Place the angle sensor on the test platform, and by changing the magnetic field direction, measure the output signal of the sensor. Its sensing output characteristic diagram is as Figure 4 shown. It can be seen from Figure 4 that the sensor can stably output double-angle sine and cosine waveform resistivity signals with a phase difference of 45°. And within the induction range of 0 - 360°, the signals are unique and highly stable, meeting the design requirements. After measurement, the overall size of the sensor is in the order of hundreds of micrometers, realizing miniaturization and integration, and can be further applied to high-tech fields such as communication, sensing and storage.

[0033] The above are only embodiments of the present invention, and common general technical solutions or characteristics in the solutions are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which 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 practicability of the patent. The protection scope claimed in this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. An angle sensor device based on room temperature planar Hall effect, characterized in that: The sensor device uses silicon / silicon oxide as the substrate, the functional layer is 18-nanometer thick dibismuth rhodium nanosheets, it uses hexagonal-boron nitride cover packaging, and the conductive microelectrodes are prepared by electron beam exposure process. The overall size of the device is in the order of hundreds of microns. The sensor device can achieve a double-angle sine-cosine waveform resistivity signal with a phase difference of 45° under a strong magnetic field at room temperature. Within the range of 0-360°, the signal is unique and highly stable.

2. The angle sensor device based on room temperature planar Hall effect according to claim 1, characterized in that: The device is used in high-tech fields such as communication, sensing, and storage.

3. The method for preparing an angle sensor device based on room temperature planar Hall effect according to claim 1, characterized in that: The following steps are involved: S1, cleaning silicon / silicon oxide substrate; S2, sticking the tape to the surface of the rhodium dibismuth single crystal, and then peeling the tape from the surface of the rhodium dibismuth single crystal, the tape will adhere to part of the rhodium dibismuth material, and the tape is bonded to the substrate cleaned in step S1, and after peeling off the tape, an atomic force microscope is used to screen out nanosheets with a thickness of 18 nanometers; S3, spin-coating the substrate of step S2 with electron beam photoresist, drying the photoresist, and then exposing the Hall strip electrode shape on the dibismuth rhodium nanosheets through an electron beam exposure process, and removing the exposed part through development and fixing operations to realize the Hall strip channel structure; S4, depositing a gold film by thermal evaporation process to cover the device in step S3, removing the remaining photoresist by soaking in acetone, retaining the metal electrode of the Hall structure, and realizing the transfer of the Hall bar pattern; S5. Use a polydimethylsiloxane film to peel off the nanosheets from the surface of the hexagonal boron nitride, and cover them on the device of step S4 through a two-dimensional material transfer system to complete the packaging.

4. The method for preparing an angle sensor device based on room temperature planar Hall effect according to claim 3, characterized in that: The cleaning process in step S1 is: ultrasonic cleaning with deionized water to remove dust particles on the surface, ultrasonic cleaning with propanol and ethanol in sequence to remove organic pollutants, and finally drying with nitrogen to ensure that the substrate surface is clean.

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