Angle sensor device based on room temperature planar Hall effect and preparation method thereof

Abstract

The present invention belongs to the field of sensor technology and discloses an angle sensor based on the room temperature planar Hall effect and a preparation method thereof. The sensor uses silicon / silicon oxide as a substrate, and the functional layer is an 18-nanometer-thick dibismuth rhodium nanosheet. It is encapsulated with hexagonal-boron nitride and the conductive microelectrodes are prepared by electron beam exposure process. The overall size is hundreds of microns. It can output a double-angle sine-cosine waveform resistivity signal with a phase difference of 45° under a strong magnetic field at room temperature. The sensing range is 0-360°, and the signal is unique and stable. The preparation process includes the steps of substrate cleaning, nanosheet transfer and screening, Hall electrode preparation, metal electrode formation and packaging. The sensor has the characteristics of miniaturization and high performance, and is suitable for fields such as communications, sensing and storage, showing significant application advantages.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to an angle sensor device based on 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 the field of high-tech, especially in the fields of communication, sensing, storage, etc., which have extremely stringent requirements on the accuracy, stability and size of angle sensors.

[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 from 0-360°, making it difficult to meet diverse needs. In addition, in terms of stability and uniqueness, traditional sensors cannot guarantee that they will always provide accurate and reliable signals 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 its preparation method. The device innovatively uses 18-nanometer-thick rhodium dibismuth (RhBi2) nanosheets as the functional layer. This material has excellent electrical properties, laying the foundation for the high-performance operation of the sensor. Electron beam lithography is used to prepare the conductive microelectrodes, enabling the sensor to output a double-angle sine-cosine waveform resistivity signal with a 45° phase difference under a strong magnetic field at room temperature. The sensing range covers 0-360°, ensuring the uniqueness and high stability of the angle. Furthermore, the sensor's overall size is in the hundreds of microns, meeting the requirements of miniaturization and integration, and showing great application prospects in many high-tech fields.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A room-temperature planar Hall effect-based angle sensor device uses silicon / silicon oxide as a substrate, with a functional layer consisting of 18-nanometer-thick dibismuth rhodium nanosheets. It is encapsulated using hexagonal-boron nitride cover, and the conductive microelectrodes are prepared using an electron beam lithography process. The overall size of the device is on the order of hundreds of microns. Under a strong magnetic field at room temperature, the sensor device can produce a double-angle sine-cosine waveform resistivity signal with a phase difference of 45°. Within the range of 0-360°, the signal is unique and highly stable.

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

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

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

[0011] S2, sticking a tape to the surface of the rhodium dibismuth single crystal, then peeling the tape off the surface of the rhodium dibismuth single crystal, the tape will adhere to a portion of the rhodium dibismuth material, and adhering the tape to the substrate cleaned in step S1. After peeling off the tape, use an atomic force microscope to screen out nanosheets with a thickness of 18 nanometers;

[0012] S3, spin-coating electron beam photoresist on the substrate of step S2, drying the photoresist, and then exposing the Hall strip electrode shape on the dibismuth rhodium nanosheet by electron beam exposure process, and removing the exposed part by development and fixing operations to realize the Hall strip channel structure;

[0013] S4, depositing a gold film by thermal evaporation to cover the device in step S3, and removing the remaining photoresist by soaking in acetone to retain the metal electrodes of the Hall structure, thereby transferring the Hall bar pattern;

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

[0015] Furthermore, the cleaning process in step S1 is: ultrasonic cleaning with deionized water to remove surface dust particles, then 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.

[0016] The technical solution has the following beneficial effects: The present invention provides a room-temperature planar Hall effect-based angle sensor device. Its key layer is 18-nanometer-thick rhodium dibismuth (RhBi2) nanosheets. Due to their unique crystal structure and electronic properties, the RhBi2 nanosheets possess excellent electrical performance, laying the foundation for high-performance device operation. The device utilizes a hexagonal-benzene nitride overlay package, effectively protecting the functional layer and improving sensor stability and reliability. Electron beam lithography is used to fabricate conductive microelectrodes, enabling precise device control.

[0017] The sensor of the present invention can operate at room temperature of 300K and a strong magnetic field environment of 14T, and can output a double-angle sine-cosine waveform resistivity signal with a phase difference of 45°. Its sensing range covers the entire angle range of 0-360°, breaking through the limitations of the sensing range of traditional angle sensors, and can ensure the uniqueness and high stability of the signal at any angle, greatly improving the accuracy and reliability of angle measurement. In addition, the overall size of the sensor of the present invention is at the level of hundreds of microns, meeting the requirements of miniaturization and integration, facilitating integrated application in various complex systems, and showing great application potential in high-tech fields such as communications, sensing, and storage.

[0018] The preparation process of the device of the present invention innovatively combines specific materials with advanced technology, which 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 Schematic top view of the sensor of the present invention;

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

[0021] Figure 3 A top view of the sensor of the present invention;

[0022] Figure 4 This is a characteristic diagram of the sensor output of the present invention. DETAILED DESCRIPTION

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

[0024] like Figure 1-Figure 3 As shown in FIG, a schematic diagram of the structure of an angle sensor device based on the room temperature planar Hall effect of the present invention is shown in FIG. Figure 1 The diagram below shows a top view of the sensor. Figure 2 The cross-sectional diagram of the sensor is shown as Figure 3 Shown is the top view of the actual sensor.

[0025] A method for preparing an angle sensor device based on room temperature planar Hall effect, comprising the following steps:

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

[0027] 2. Substrate Cleaning: Clean the silicon / silicon oxide substrate using ultrasonic cleaning with deionized water to remove surface dust particles. Then, ultrasonic cleaning with acetone and acetic acid is performed sequentially to remove organic contaminants. Finally, dry with nitrogen to ensure a clean substrate surface, providing a good foundation for subsequent operations.

[0028] 3. Obtaining Rhodium Dibismuth Nanosheets: Adhesive tape is tightly applied to the surface of a Rhodium Dibismuth single crystal and then carefully peeled off. The tape will adhere to some of the Rhodium Dibismuth material. The tape is then bonded to a cleaned silicon / silicon oxide substrate and slowly peeled off, transferring the Rhodium Dibismuth material to the substrate. An atomic force microscope scans the transferred material, accurately selecting Rhodium Dibismuth nanosheets approximately 18 nanometers thick, which will serve as the sensor's functional layer.

[0029] 4. Preparation of Hall strip electrodes: Electron beam photoresist is evenly spin-coated on a substrate containing selected Rhodium dibismuth nanosheets. The coated substrate is placed in an oven and dried at an appropriate temperature to cure the photoresist. Using an electron beam exposure device, the Rhodium dibismuth nanosheets are exposed to the pre-designed Hall strip electrode shape. After exposure, the exposed portion of the photoresist is removed using a developer, and then fixed with a fixer, thereby achieving the Hall strip channel structure.

[0030] 5. Forming the Metal Electrode: Using a thermal evaporation process, a gold film is deposited on the device with the Hall bar channel structure, ensuring that the gold film evenly covers the device. The gold-deposited device is then immersed in an acetone solution. Since acetone dissolves uncured photoresist, after a period of soaking, the remaining photoresist is removed, leaving the metal electrode of the Hall structure, completing the transfer of the Hall bar pattern.

[0031] 6. Encapsulation: Nanosheets are exfoliated from the hexagonal-boron nitride surface using a polydimethylsiloxane film. Using a two-dimensional material transfer system, the exfoliated hexagonal-boron nitride nanosheets are precisely applied to a device with prepared metal electrodes, completing the sensor package and improving its stability and anti-interference capabilities.

[0032] The performance test of the prepared angle sensor was carried out. The angle sensor was placed on the test platform and the sensor output signal was measured by changing the direction of the magnetic field. The sensor output characteristic diagram is shown in the figure below. Figure 4 As shown, from Figure 4 The sensor can stably output a double-angle sine-cosine waveform resistivity signal with a 45° phase shift. Within the sensing range of 0-360°, the signal is unique and highly stable, meeting the design requirements. Measurements indicate that the sensor's overall size is in the hundreds of microns, achieving miniaturization and integration, potentially enabling further application in high-tech fields such as communications and sensor storage.

[0033] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. An angle sensor device based on room temperature planar Hall effect, characterized by: The sensor device uses silicon / silicon oxide as the substrate, and the functional layer is an 18-nanometer-thick dibismuth rhodium nanosheet. It is covered and packaged with hexagonal boron nitride, and the conductive microelectrodes are prepared using electron beam exposure technology. The overall size of the device is at the level 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 the room temperature planar Hall effect according to claim 1, characterized in that: The device is used in high-tech fields such as communications, 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. Clean silicon / silicon oxide substrate; S2, sticking a tape to the surface of the rhodium dibismuth single crystal, then peeling the tape off the surface of the rhodium dibismuth single crystal, the tape will adhere to a portion of the rhodium dibismuth material, and adhering the tape to the substrate cleaned in step S1. After peeling off the tape, use an atomic force microscope to screen out nanosheets with a thickness of 18 nanometers; S3, spin-coating electron beam photoresist on the substrate of step S2, drying the photoresist, and then exposing the Hall strip electrode shape on the dibismuth rhodium nanosheet by electron beam exposure process, and removing the exposed part by development and fixing operations to realize the Hall strip channel structure; S4, depositing a gold film by thermal evaporation to cover the device in step S3, and removing the remaining photoresist by soaking in acetone to retain the metal electrodes of the Hall structure, thereby transferring the Hall bar pattern; S5. Use polydimethylsiloxane film to peel off nanosheets from the surface of hexagonal boron nitride, and cover them on the device in 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 as follows: 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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