Two-dimensional magnetic sensitive sensor based on two-dimensional electron gas channel structure and preparation method thereof

Abstract

This invention relates to a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure and its fabrication method, belonging to the field of semiconductor sensor technology. Technical solution: A buffer layer, a channel layer, and a barrier layer are sequentially grown on a substrate. The channel layer and the barrier layer form a heterojunction structure layer. A two-dimensional electron gas is induced at their interface by polarization charges. A magnetostrictive layer is placed above the barrier layer, and electrodes Sx1, Sx2, Sy1, and Sy2 are placed above the magnetostrictive layer. Electrodes Sx1, Sx2, Sy1, and Sy2 all extend from above the magnetostrictive layer to the heterojunction structure layer. Electrodes Sx1 and Sx2 are symmetrically arranged, as are electrodes Sy1 and Sy2. Beneficial effects: The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure described in this invention modulates the polarization effect of a single III-V group semiconductor heterojunction magnetic sensor. It can achieve high sensitivity when measuring magnetic fields parallel to the device direction under harsh environments, and the simple structure reduces the device size and facilitates integration.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor sensor technology, and particularly relates to a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure and its fabrication method. Background Technology

[0002] Novel smart materials typically consist of two or more materials with physical properties including electrical, magnetic, optical, thermal, and acoustic properties. The coupling of these multiple physical properties can meet the needs of modern high-tech equipment and novel smart devices. For example, magnetostrictive materials and semiconductor materials can provide conversion between magneto-electric and optical forces; piezoelectric materials and semiconductor materials are widely used in deep space exploration. Semiconductor power devices, due to their wide temperature range and ability to operate in extreme environments, are widely used in space satellites for energy conversion, while piezoelectric materials, due to their excellent magneto-electric conversion capabilities, are commonly used in sensors and transducers. Therefore, developing novel smart material devices that can operate in harsh environments has significant application implications.

[0003] Currently, magnetic sensors, which hold a significant market share, are typically made from traditional materials such as silicon (Si) and germanium (Ge). However, first-generation semiconductor materials, primarily based on silicon (Si) and germanium (Ge), are limited by their low bandgap and low electron mobility, making them unsuitable for high-frequency, high-power applications. In contrast, III-V group semiconductor materials, primarily composed of gallium arsenide (GaAs), indium arsenide (InAs), gallium nitride (GaN), and indium antimonide (InSb), possess high electron mobility (GaAs and InAs can reach 9000 cm⁻¹). 2 / (V·s), 40000cm 2 These materials (V·s) exhibit excellent electron transport properties under both low and high fields, making them ideal channel materials for ultra-high-speed, low-power sensors. Magnetic sensors fabricated from their heterojunction materials have a high concentration of two-dimensional electron gas (2DEG) at the heterojunction interface, resulting in high device sensitivity.

[0004] Meanwhile, GaN, a third-generation semiconductor material, boasts a large bandgap, high critical breakdown electric field, and high saturated electron drift velocity, enabling it to operate stably within a temperature range of 400℃. This gives it significant material advantages and broad application prospects in the fabrication of high-temperature magnetic sensors. Furthermore, GaN semiconductors possess unique piezoelectric properties, allowing it to be used as a piezoelectric layer in devices. The AlGaN / GaN heterojunction structure it generates, due to its spontaneous polarization and piezoelectric polarization effects, produces a 2DEG with high mobility at the heterojunction interface. Based on the Hall effect, magnetic sensors fabricated using this technology exhibit high sensitivity when measuring magnetic fields perpendicular to the device direction.

[0005] Existing III-V semiconductor heterojunction (typically AlGaN / GaN heterojunction) magnetic sensors exhibit a high density of 2DEGs induced by polarization charges in the potential well at the heterojunction interface due to the spontaneous polarization and piezoelectric polarization effects of the material itself. When measuring a magnetic field perpendicular to the device surface, the 2DEGs can move freely in two-dimensional space, generating a potential difference between the corresponding two electrodes, resulting in high device sensitivity. However, when measuring a magnetic field parallel to the device surface, the Hall effect creates a longitudinal electric field perpendicular to the 2DEG channel, binding electrons in the channel and preventing them from moving freely in the vertical direction. This reduces the current and voltage sensed by the sensor, thus decreasing the sensor sensitivity. Furthermore, this type of magnetic sensor has a large number of electrodes, resulting in a large size, which is not conducive to integration. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure. This novel structure combines a III-V group semiconductor heterojunction with a magnetostrictive material (typically Terfenol-D) to serve as a two-dimensional magnetic sensor for measuring magnetic fields parallel to the device surface under harsh environments. The tensile stress (strain) generated by the magnetostrictive material under the influence of a magnetic field due to the magnetostrictive effect can counteract the compressive stress generated during the fabrication of the III-V group semiconductor heterojunction, reducing the polarization effect of the heterojunction and causing a significant change in the concentration of 2DEG, thereby improving the sensitivity of the magnetic sensor. Furthermore, by using four electrodes instead of multiple electrodes to achieve the detection of a two-dimensional magnetic field parallel to the device surface, the device size is reduced while ensuring stable sensor operation.

[0007] This invention application presents a structural innovation and fabrication of a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure for detecting magnetic fields parallel to the surface of a device.

[0008] The technical solution is as follows:

[0009] A two-dimensional magnetosensitive sensor based on a two-dimensional electron gas channel structure includes: a substrate, a buffer layer, a channel layer, a barrier layer, a magnetostrictive layer, and electrodes Sx1, Sx2, Sy1, and Sy2. The buffer layer, channel layer, and barrier layer are sequentially grown on the substrate. The channel layer and barrier layer form a heterojunction structure layer. Two-dimensional electron gas is generated at their interface by polarization charge. The magnetostrictive layer is disposed above the barrier layer. Electrodes Sx1, Sx2, Sy1, and Sy2 are disposed above the magnetostrictive layer. Electrodes Sx1, Sx2, Sy1, and Sy2 all extend from above the magnetostrictive layer to the heterojunction structure layer. Electrodes Sx1 and Sx2 are symmetrically arranged, and electrodes Sy1 and Sy2 are symmetrically arranged.

[0010] Furthermore, the substrate is silicon, silicon carbide, sapphire, or other substrates of the same material as the channel layer.

[0011] Furthermore, the buffer layer is an AlN or GaN or a superlattice structure, and the thickness of the buffer layer is 10-100 nm.

[0012] Furthermore, the channel layer is a thin film structure composed of GaN, GaAs, InSb, InAs or other group III-V semiconductors, and the thickness of the channel layer is 0.1 to 50 μm.

[0013] Furthermore, the barrier layer is an AlGaN, InGaAs, AlGaAs, InAlN, or other thin film structures that can form a heterojunction with a III-V group semiconductor, and the thickness of the barrier layer is 5 to 100 nm.

[0014] Furthermore, the magnetostrictive layer is a thin film structure composed of magnetostrictive materials such as terbium-dysprosium-iron alloy (GMM, Terfenol-D), brittle modified terbium-dysprosium-iron alloy (TD-plus), and iron-gallium alloy (Galfenol), and the thickness of the magnetostrictive layer is 0.05 to 5 μm.

[0015] Furthermore, the electrodes Sx1, Sx2, Sy1, and Sy2 are rectangular or trapezoidal in shape.

[0016] This invention also includes a method for fabricating a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure, the steps of which are as follows:

[0017] S1. Substrate preparation: Prepare the substrate, clean the substrate material, and remove contaminants from the substrate surface;

[0018] S2. Epitaxial growth: The buffer layer and heterojunction structure layer are epitaxially grown using any one of the following methods: metal-organic chemical vapor deposition, molecular beam epitaxy, or hydride vapor phase epitaxy. The thickness of the generated channel layer is 0.1–50 μm, the thickness of the barrier layer on the channel layer is 5–100 nm, and the buffer layer is one of AlN, GaN, or a superlattice structure with a thickness of 10–100 nm.

[0019] S3. Mesa etching: After photolithography and development, the epitaxially grown sample is etched using inductively coupled plasma etching, with a mesa etching depth of 50-800 nm.

[0020] S4. Magnetostrictive layer growth: Magnetostrictive thin films are prepared by any one of magnetron sputtering, molecular beam epitaxy, ion beam sputtering, vacuum thermal evaporation, ion plating, or flash evaporation, and the thickness of the generated magnetostrictive thin film is 0.05 to 5 μm.

[0021] S5. Shallow etching: After the magnetostrictive layer has been grown, the sample is etched using inductively coupled plasma etching after photolithography and development. The etching depth is 0.05 to 5.1 μm.

[0022] S6. Electrode Ohmic Contact Fabrication: After photolithography and development, composite metal is deposited using an electron beam evaporation system, followed by rapid annealing to form a good ohmic contact.

[0023] S7. Surface passivation: The device passivation is performed by depositing a dielectric layer using any one of the following methods: plasma-enhanced chemical vapor deposition, magnetron sputtering, atomic layer deposition, or electron beam evaporation.

[0024] S8. Window opening: The passivation layer at the electrode is photolithographically etched and etched to form a window. Metal is deposited at the electrode using any of the following methods: magnetron sputtering, electron beam evaporation, or thermal evaporation to create a pad and make leads.

[0025] Furthermore, in step S2, an AlN insertion layer of 0.5–2 nm is grown between the barrier layer and the channel layer to increase the flatness between the two layers and increase the concentration and mobility of the two-dimensional electron gas.

[0026] Furthermore, in step S3, the heterojunction is etched using inductively coupled plasma etching with an etching power of 100–1000 W and a Cl-based gas of 150–500 sccm, ultimately forming an etching depth of approximately 50–800 nm.

[0027] The beneficial effects of this invention are:

[0028] The two-dimensional magnetosensitive sensor based on a two-dimensional electron gas channel structure proposed in this invention is a novel III-V group semiconductor heterojunction / magnetostrictive material composite structure magnetosensitive sensor, and its technical solution brings the following benefits:

[0029] 1) III-V semiconductors have high electron mobility and excellent electron transport performance under both low and high fields. They are ideal channel materials for ultra-high speed and low power consumption sensors. Magnetic sensors made from their heterojunction materials have a high concentration of 2DEG at the heterojunction interface and have high device sensitivity.

[0030] 2) Gallium-based materials are currently the most widely used III-V group semiconductor materials (typically GaN). They have a large band gap and a large breakdown electric field. Magnetic sensors made from them can work stably in high temperature (above 400℃), high pressure (below 650V), and high radiation environments.

[0031] 3) Magnetostrictive materials (such as Terfernol-D) produce magnetostrictive strain that is hundreds of times or even higher than that of traditional materials. They have a large linear strain response range to magnetic fields and a fast response speed, and have the characteristic of outputting large strain under low magnetic fields.

[0032] 4) The magnetostrictive strain of magnetostrictive materials has a modulating effect on the polarization of III-V semiconductor materials. Under the action of an axial magnetic field, the polarization effect of the barrier layer changes, thereby affecting the carrier transport, energy level conversion, and recombination process of the two-dimensional electron gas channel, which improves the sensitivity of the magnetic sensor.

[0033] 5) The device has a simple structure, using only four electrodes to detect the magnetic field parallel to the device surface. It boasts low manufacturing costs, small size, and ease of integration. This novel composite magnetic sensor achieves high-sensitivity measurement of magnetic fields parallel to the device surface, with a maximum sensitivity of 4.45 V / T. It also has a wide measurement range, capable of measuring magnetic fields from 0 to 320 mT parallel to the device surface. This technology is expected to drive the development of 3D magnetic sensors and find widespread application in the fields of micro and nanoscale sensors. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0035] Figure 1 This is a schematic diagram of a two-dimensional magnetic sensor structure based on a two-dimensional electronic gas channel structure proposed in this invention application.

[0036] Figure 2 These are side and top views of the two-dimensional magnetic sensor based on a two-dimensional electronic gas channel structure proposed in this invention application;

[0037] Figure 3 This is a process flow diagram of a specific embodiment of the present invention.

[0038] Figure 4 The experimental characteristic curves of a specific embodiment of the two-dimensional magnetosensitive sensor based on a two-dimensional electron gas channel structure proposed in this invention application are shown below: 2DEG concentration at the AlGaN / GaN heterojunction interface as a function of magnetostrictive strain ε of the Terfernol-D material. H The change graph;

[0039] Figure 5This is an experimental characteristic curve of a specific embodiment of the two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure proposed in this invention application - a characterization curve of the device's magnetic field detection capability. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The following description, in conjunction with the accompanying drawings... Figure 1-5 The paper further explains the two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure and its fabrication method.

[0041] Example 1

[0042] To address the technical problems described in the background and to realize a magnetic sensor with high sensitivity and small size capable of measuring the magnetic field on the surface of parallel devices, this invention proposes a specific embodiment of a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure. A schematic diagram of the device structure is shown below. Figure 1 As shown. In specific embodiment 1 of the present invention, the substrate is a silicon (Si) substrate, on which a buffer layer and an AlGaN / GaN heterojunction structure are epitaxially grown. The buffer layer can be AlN or GaN (thickness 10-100 nm), GaN is the channel layer (thickness 0.1-50 μm), and an AlGaN barrier layer (thickness 5-100 nm) is placed on the channel layer. The material composition in the barrier layer is not limited. A Terfernol-D magnetostrictive layer (thickness 0.05-5 μm) is placed on the AlGaN barrier layer. The electrodes Sx1 and Sx2 are symmetrical with each other and Sy1 and Sy2 are symmetrical. The electrode shape is not particularly limited and can be rectangular, trapezoidal, etc. The electrodes and the semiconductor material need to form good ohmic contact.

[0043] The working principle of the two-dimensional magnetic sensor device based on a two-dimensional electron gas channel structure proposed in this invention application is as follows: Figure 2 As shown, the input and output are in the same loop, and a certain current I is applied between electrodes Sx1 and Sx2 or Sy1 and Sy2. bias The output voltage V between Sx1 and Sx2 or Sy1 and Sy2 is detected under the influence of a magnetic field. outIn specific embodiment 1 of the present invention, the AlGaN / GaN heterojunction material forms a potential well at the heterojunction interface as a piezoelectric layer, accumulating a two-dimensional electron gas with high mobility. The Terfernol-D material acts as a magnetostrictive layer, generating strain in physical dimensions through the response to the axial magnetic field. The strain is transmitted to the piezoelectric layer, changing the polarization charge density at the AlGaN / GaN heterojunction interface, thus altering the concentration of the two-dimensional electron gas. The device detects a larger voltage change than the vertical Hall sensor of a III-V semiconductor heterojunction, resulting in higher sensitivity.

[0044] The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure proposed in this invention application modulates the polarization effect of a single III-V semiconductor heterojunction magnetic sensor, achieving high sensitivity when measuring magnetic fields parallel to the device direction. Furthermore, the simple structure reduces the device size and facilitates integration.

[0045] The implementation process of the target device of this invention application is described as follows:

[0046] 1) Substrate preparation: Prepare the substrate, clean the substrate material, and remove contaminants from the substrate surface.

[0047] 2) Epitaxial growth: AlGaN / GaN heterojunction structures and buffer layers are epitaxially grown using any one of the following methods: metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or hydride vapor phase epitaxy (HVPE). The thickness of the GaN channel layer is 0.1–50 μm, the thickness of the AlGaN barrier layer on the channel layer is 5–100 nm, and the buffer layer can be AlN, GaN, or a superlattice structure with a thickness of 10–100 nm.

[0048] 3) Mesa etching: After photolithography and development, the epitaxially grown sample is etched using inductively coupled plasma etching (ICP) with a mesa etching depth of 50–800 nm.

[0049] 4) Magnetostrictive layer growth: Terfernol-D thin films were prepared by any one of the following methods: magnetron sputtering, molecular beam epitaxy, ion beam sputtering, vacuum thermal evaporation, ion plating, or flash evaporation, with a film thickness of 0.05–5 μm.

[0050] 5) Shallow etching: After the magnetostrictive layer is grown, the sample is etched by inductively coupled plasma etching (ICP) after photolithography and development, with an etching depth of 0.05 to 5.1 μm.

[0051] 6) Fabrication of ohmic contacts: After photolithography and development, composite metal is deposited using an electron beam evaporation system, followed by rapid annealing (RTA) to form good ohmic contacts.

[0052] 7) Surface passivation: The device passivation is performed by depositing a dielectric layer using any one of the following methods: plasma enhanced chemical vapor deposition (PECVD), magnetron sputtering, atomic layer deposition (ALD), or electron beam evaporation (EB).

[0053] 8) Window opening: The passivation layer at the electrode is photolithographically etched and etched to form a window. Metal is deposited at the electrode using any one of the following methods: magnetron sputtering, electron beam evaporation (EB), or thermal evaporation to create a pad and make a lead.

[0054] The purpose of this invention is to provide a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure that can measure magnetic fields parallel to the device surface, has higher sensitivity, fewer electrodes, and smaller size.

[0055] The polarization effect of III-V group semiconductor heterojunction materials forms a potential well at the heterojunction interface, in which a two-dimensional electron gas (2DEG) with high mobility accumulates. When a magnetic sensor based on the Hall effect measures a magnetic field parallel to the device surface, the 2DEG is affected by the longitudinal electric field in the direction perpendicular to the channel, and cannot move freely in the vertical direction. As a result, the voltage and current detected by the sensor at the two ends of the detection electrode are small, and the sensor sensitivity performance is poor. Therefore, this application proposes a novel two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure with a composite structure of III-V group semiconductor and magnetostrictive material to measure the magnetic field parallel to the device surface.

[0056] Magnetic sensors made by incorporating magnetostrictive materials (typically Terfenol-D) into III-V semiconductor heterojunctions no longer rely on the Hall effect. Instead, they utilize the magnetostrictive effect of materials like Terfenol-D and FeGaB, where their physical dimensions change under an axial magnetic field. The magnetostrictive strain produced by these materials is approximately a hundred times greater than that of traditional materials, allowing them to operate at lower magnetic field strengths with a rapid strain response to changes in the magnetic field and a relatively large linear strain response range. Simultaneously, the strain in the magnetostrictive material alters the polarization effect of the III-V semiconductor heterojunction, affecting the polarization charge density at the heterojunction interface. This results in changes to the device's band structure and electron concentration, leading to significant alterations in the voltage and current at the sensor's detection point and improving the device's sensitivity. On the other hand, a single III-V semiconductor heterojunction magnetic sensor based on the Hall effect that can measure the magnetic field on the surface of a parallel device has many electrodes (typically nine electrodes), which increases the manufacturing cost and has a large volume. The magnetic sensor made of composite magnetostrictive material in the III-V semiconductor heterojunction material proposed in this application has only four detection electrodes to detect the current, thereby realizing the measurement of the magnetic field parallel to the device direction. It has low manufacturing cost, reduced volume, and is easy to integrate.

[0057] This invention proposes a novel magnetic sensor technology using a III-V semiconductor heterojunction / magnetostrictive material composite structure. The characteristics of this device structure are: 1) III-V semiconductors have high electron mobility and excellent electron transport performance under both low and high fields. The magnetic sensor fabricated from its heterojunction material exhibits a high concentration of 2DEG at the heterojunction interface, resulting in high device sensitivity; 2) Gallium-based materials are currently widely used III-V semiconductor materials (typically GaN), with a large bandgap and a large breakdown electric field. The magnetic sensor fabricated from these materials can operate stably under high temperature (above 400℃), high voltage (below 650V), and high radiation environments; 3) Magnetostrictive… Magnetostrictive strain produced by extensible materials (typically Terfernol-D) is hundreds of times or even higher than that of traditional materials. It has a large linear strain response range and fast response speed to magnetic fields, and has the characteristic of large strain output under low magnetic fields; 4) The magnetostrictive strain of magnetostrictive materials has a modulating effect on the polarization of III-V semiconductor materials. Under the action of an axial magnetic field, the polarization effect of the barrier layer is changed, thereby affecting the carrier transport, energy level conversion and recombination process of the two-dimensional electron gas channel, which improves the sensitivity of the magnetic sensor; 5) The device has a simple structure, using only 4 electrodes to complete the detection of the magnetic field on the surface of the parallel device. It has low process cost, small size and easy integration.

[0058] The key technical point of this invention lies in the innovative structure of a III-V semiconductor heterojunction magnetic sensor. It combines magnetostrictive materials with III-V semiconductor heterojunction materials, utilizing the magnetostrictive effect to replace the Hall effect, thus achieving the measurement of magnetic fields parallel to the device surface. While ensuring high sensitivity, this solution features a simple structure and small size. The device fabrication process reduces the degree of lattice matching while ensuring good ohmic contact of the electrodes, significantly improving the performance of the device. This invention primarily protects the proposed device structure design and fabrication process.

[0059] Example 2

[0060] like Figure 3 The specific manufacturing process of this embodiment is described below:

[0061] 1) Substrate preparation: Prepare the substrate, clean the substrate material, and remove contaminants from the substrate surface.

[0062] 2) Epitaxial growth: AlGaN / GaN heterojunction structures and AlN buffer layers were epitaxially grown using metal-organic chemical vapor deposition (MOCVD). The resulting GaN channel layer was unintentionally doped, with a thickness of 3 μm and a background electron concentration of 1 × 10⁻⁶. 16 cm -3The AlGaN barrier layer on the channel layer is 25 nm thick, with an Al composition of 0.1%. The buffer layer is AlN with a thickness of 50 nm. Simultaneously, a 1 nm AlN insertion layer is grown between the AlGaN and GaN layers to increase the flatness between the two layers and to increase the concentration and mobility of the two-dimensional electron gas (2DEG).

[0063] 3) Mesa etching: After the epitaxially grown sample is coated with photoresist (using AZ6130 positive photoresist), homogenized (rotating forward at 600 rpm for 3 seconds, then rotating backward at 1000 rpm for 20 seconds, with a final photoresist thickness of 2 μm), photolithography, and development (90 seconds), the heterojunction is etched using inductively coupled plasma etching (ICP) at a power of 200 W and with 150 sccm of Cl-based gas introduced for 250 seconds, resulting in an etching depth of approximately 400 nm.

[0064] 4) Magnetostrictive layer growth: Terfernol-D thin films ((Tb) were prepared by DC magnetron sputtering. 0.28 Dy 0.72 )Fe 1.99 The targets are Fe targets and Tb and Dy sheets. The stage is rotated so that the sputtering baffle is directly above the targets, and the back-bottom vacuum is evacuated to 1×10⁻⁶. -5 After Pa, Ar gas is introduced, sputtering parameters are adjusted, the baffle is opened to start sputtering, and after the specified time, the baffle is closed to stop sputtering; the substrate is then placed in the annealing heat treatment apparatus, the heating and temperature control power supply is turned on, and the heating rate, cooling rate, temperature, and holding time are set to maintain a vacuum of 3 × 10⁻⁶. -4 Terfernol-D thin films were subjected to vacuum heat treatment at a temperature below Pa to achieve a final film thickness of approximately 820 nm.

[0065] 5) Shallow etching: After coating (using AZ6130 positive photoresist), homogenization (rotating forward at 600 rpm for 3 seconds, then backward at 1000 rpm for 20 seconds, resulting in a final photoresist thickness of 2 μm), photolithography, and development (90 seconds), the sample is etched using inductively coupled plasma etching (ICP) at a power of 200 W. Cl-based gas is introduced at 150 sccm for 500 seconds, ultimately forming an etching depth of approximately 840 nm.

[0066] 6) Fabrication of ohmic contacts: After photolithography and development, four metal layers of Ti (20nm), Al (100nm), Ni (45nm), and Au (55nm) were deposited using an electron beam evaporation system. Then, a good ohmic contact was formed by annealing at 850°C in a nitrogen atmosphere for 30 seconds using a rapid annealing (RTA) process.

[0067] 7) Surface passivation: A 300 nm thick SiO2 passivation layer is deposited at 300 °C using plasma-enhanced chemical vapor deposition (PECVD) to reduce the influence of the ambient atmosphere on device characteristics.

[0068] 8) Window Opening: Etching the passivation layer at the electrode and opening the window lead wire. After the sample is coated with photoresist (using AZ6130 positive photoresist), homogenized (600rpm-3s forward, 1000rpm-20s backward, final photoresist thickness of 2um), photolithography, and development (90 seconds), the passivated electrode is etched using ICP etching to form a window. Then, 500nm of Al is deposited at the electrode using magnetron sputtering, and finally, the electrode is led out.

[0069] Figure 4 and Figure 5 The characteristic curves of the magnetic sensor in Embodiment 2 of this application are given. Figure 4 This indicates the change in 2DEG concentration at the AlGaN / GaN heterojunction interface under the influence of the magnetostrictive strain of Terfenol-D materials. The 2DEG concentration at the heterojunction interface varies with the magnetostrictive strain ε of Terfenol-D. H The increase in concentration is linear, compared to a relative change of 12.45% in 2DEG concentration without Terfenol-D material; Figure 5 The excitation current I is given bias The variation trend of the detection voltage with the magnetic field in Embodiment 2 of this invention at 1mA shows that, due to the influence of the magnetostrictive strain of the Terfenol-D material on the saturation magnetization, the detection voltage changes nonlinearly with the increase of the magnetic field. The magnetic field measurement range is 0–320mT. When the magnetic field exceeds 320mT, magnetic saturation is reached, and the magnetostrictive strain no longer changes, resulting in no change in voltage. The maximum sensitivity of the device is 4.45V / T, which is far greater than that of existing magnetic sensors for measuring the magnetic field on the surface of parallel devices.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure, comprising: A substrate, a buffer layer, a channel layer, a barrier layer, a magnetostrictive layer, and electrodes Sx1, Sx2, Sy1, and Sy2 are characterized in that the buffer layer, the channel layer, and the barrier layer are grown sequentially on the substrate, the channel layer and the barrier layer form a heterojunction structure layer, and a two-dimensional electron gas is generated at their contact interface by polarization charge. The magnetostrictive layer is disposed above the barrier layer, and the electrodes Sx1, Sx2, Sy1, and Sy2 are disposed above the magnetostrictive layer. The electrodes Sx1, Sx2, Sy1, and Sy2 all extend from above the magnetostrictive layer to the heterojunction structure layer. The electrodes Sx1 and Sx2 are symmetrically arranged, and the electrodes Sy1 and Sy2 are symmetrically arranged.

2. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The substrate is silicon, silicon carbide, sapphire, or a substrate made of the same material as the channel layer.

3. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The buffer layer is an AlN or GaN or a superlattice structure, and the thickness of the buffer layer is 10-100 nm.

4. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The channel layer is a thin film structure composed of GaN, GaAs, InSb, InAs or III-V group semiconductors, and the thickness of the channel layer is 0.1 to 50 μm.

5. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The barrier layer is AlGaN, InGaAs, AlGaAs, InAlN, or a thin film structure that can form a heterojunction with a III-V group semiconductor, and the thickness of the barrier layer is 5 to 100 nm.

6. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The magnetostrictive layer is a thin film structure composed of any magnetostrictive material among terbium-dysprosium-iron alloy, brittle modified terbium-dysprosium-iron alloy, and iron-gallium alloy, and the thickness of the magnetostrictive layer is 0.05 to 5 μm.

7. The two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 1, characterized in that, The electrodes Sx1, Sx2, Sy1, and Sy2 are rectangular or trapezoidal in shape.

8. A method for fabricating a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure, characterized in that, The steps are as follows: S1. Substrate preparation: Prepare the substrate, clean the substrate material, and remove contaminants from the substrate surface; S2. Epitaxial growth: The buffer layer and heterojunction structure layer are epitaxially grown using any one of the following methods: metal-organic chemical vapor deposition, molecular beam epitaxy, or hydride vapor phase epitaxy. The thickness of the generated channel layer is 0.1–50 μm, the thickness of the barrier layer on the channel layer is 5–100 nm, and the buffer layer is one of AlN, GaN, or a superlattice structure with a thickness of 10–100 nm. S3. Mesa etching: After photolithography and development, the epitaxially grown sample is etched using inductively coupled plasma etching, with a mesa etching depth of 50-800 nm. S4. Magnetostrictive layer growth: Magnetostrictive thin films are prepared by any one of magnetron sputtering, molecular beam epitaxy, ion beam sputtering, vacuum thermal evaporation, ion plating, or flash evaporation, and the thickness of the generated magnetostrictive thin film is 0.05–5 μm. S5. Shallow etching: After the magnetostrictive layer has been grown, the sample is etched using inductively coupled plasma etching after photolithography and development. The etching depth is 0.05 to 5.1 μm. S6. Electrode Ohmic Contact Fabrication: After photolithography and development, composite metal is deposited using an electron beam evaporation system, followed by rapid annealing to form a good ohmic contact. S7. Surface passivation: The device passivation is performed by depositing a dielectric layer using any one of the following methods: plasma-enhanced chemical vapor deposition, magnetron sputtering, atomic layer deposition, or electron beam evaporation. S8. Window opening: The passivation layer at the electrode is photolithographically etched and etched to form a window. Metal is deposited at the electrode using any of the following methods: magnetron sputtering, electron beam evaporation, or thermal evaporation to create a pad and make leads.

9. The method for fabricating a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 8, characterized in that, In step S2, an AlN insertion layer of 0.5–2 nm is grown between the barrier layer and the channel layer to increase the flatness between the two layers and increase the concentration and mobility of the two-dimensional electron gas.

10. The method for fabricating a two-dimensional magnetic sensor based on a two-dimensional electron gas channel structure as described in claim 8, characterized in that, In step S3, the heterojunction is etched using inductively coupled plasma etching with an etching power of 100–1000 W and a Cl-based gas of 150–500 sccm, ultimately forming an etching depth of 50–800 nm.

Images