Electrical anisotropy device based on grating type gate voltage structure and preparation method thereof

Abstract

The application discloses a grating type gate voltage structure-based electrical anisotropy device and a preparation method thereof. A grating type gate voltage electrode structure is arranged on a heterojunction to establish a size-in-situ adjustable electric potential field, form an artificial stripe phase electron channel, and realize in-situ regulation and control of horizontal resistance and vertical resistance of a lower two-dimensional electron gas. Great positive magnetoresistance and negative magnetoresistance effects are realized in two mutually perpendicular directions, and great electrical anisotropy is regulated and controlled. The grating type gate voltage electrode structure is grown on a cross-shaped semiconductor heterojunction, great planar electrical anisotropy in different current directions under a magnetic field can be realized, the size of electrical anisotropy of the device can be in-situ regulated and controlled by changing the size of the gate voltage, and in addition, the method has the advantages of simple micro-processing technology, good universality, large-area batch production and the like.

Description

Technical Field

[0001] This invention belongs to the field of electrical anisotropic device technology, specifically relating to an electrical anisotropic device based on a grating-type gate voltage structure and its fabrication method. Background Technology

[0002] Anisotropic magnetoresistance (AMRs) traditionally refers to the phenomenon that the resistance of many ferromagnetic materials changes with variations in their magnetization direction and current or crystal axis angle. First discovered in 1850, it has been widely studied and applied in spintronics. Permalloy is a typical AMR material and has been widely used in magnetic recording and magnetic sensors. Nevertheless, its room-temperature AMRs are only 2% (calculated as follows: Furthermore, in some topological half-metals such as Co3Sn2S2, Cd3As2, NaBi, and other nonmagnetic materials, field-dependent currents caused by the Berry curvature of the band structure or the chiral anomalies of Dirac or Weyl fermions can also generate AMRs. In recent years, two-dimensional systems with significant in-plane anisotropy have attracted widespread attention because they have great potential for complex neuromorphic computing. For such systems, researchers have conducted extensive studies and found some natural two-dimensional materials such as black phosphorus, GaTe, and WSe2. However, natural materials with intrinsic electrical anisotropy are still rare because the effective electron mass is the same in K-valleys and K′-valleys in different directions; in addition, another condition can also cause intrinsic in-plane anisotropy: the striped phase associated with spontaneous symmetry breaking usually leads to differences in conductivity along different directions. For example, in the EuO / KTaO3(111) superconducting interface, the striped phase formed before the superconducting phase transition causes huge electrical anisotropy. Surprisingly, planar electrical anisotropy can also be induced in two-dimensional electron gas (2DEG) systems. Existing techniques have achieved the growth of sample structures with in-plane spatial distributions and the induction of transverse superlattices on sample surfaces using local surface strain. These methods can induce strip-like periodic electron distributions, resulting in electrical anisotropy. Therefore, research on artificially controlling electrical anisotropy in 2DEGs is of great significance.

[0003] However, current anisotropic planar systems suffer from problems such as small anisotropy and inability to be tunable in situ; how to realize electronic devices with huge planar electrical anisotropy and in-situ tunability remains a challenge in the current research field. Summary of the Invention

[0004] The technical problem solved by this invention is to address the issues of small anisotropy and inability to be adjusted in situ in current electrical planar anisotropic systems, and to provide an electrical anisotropic device based on a grating-type gate voltage structure and its fabrication method.

[0005] Technical Solution: To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An electrical anisotropy device based on a grating-type gate voltage structure is proposed. By setting a grating-type electrode structure on a heterojunction, an in-situ adjustable potential field is established, forming an artificial stripe phase electron channel, thereby realizing in-situ control of the transverse and longitudinal resistance of the lower 2DEGs. A huge positive magnetoresistance and negative magnetoresistance effect are achieved in two mutually perpendicular directions, thereby controlling huge electrical anisotropy.

[0007] Furthermore, by applying a gate voltage V to the grating gate... g This creates an in-situ adjustable electric potential field. Then, an external magnetic field is applied. The larger the magnetic field, the greater the electric anisotropy. The regulation of the periodic electric potential field causes a huge anisotropy in the magnetoresistance.

[0008] Furthermore, when an external vertical magnetic field is applied, the strength of the gate voltage modulation affects the anisotropy of the system.

[0009] Furthermore, the anisotropy factor AR decreases exponentially as the gate voltage decreases, and AR ≈ 1 when the gate voltage is zero or positive; as the magnetic field increases linearly, the AR value increases exponentially.

[0010] Furthermore, the method for testing in-plane conductivity anisotropy is as follows:

[0011] Current I x = I total * cosθ and I y = I total * sinθ is injected from both ends of the Hall device, controlling two power meters to continuously change the magnitude of the two currents, thereby obtaining a total value I in the middle region of the cross-shaped Hall device. total It is also a vector current that can change direction 360°.

[0012] Furthermore, the testing methods for the longitudinal and lateral resistance are as follows:

[0013] The corresponding voltage signals in different directions are tested through the electrodes at the four corners. The longitudinal and lateral resistances are calculated using the following formula:

[0014]

[0015]

[0016] Where R is the longitudinal resistance, R TV1 is the horizontal resistance, V2 is the voltage measured parallel to the grating direction, I is the current, and angle θ is the angle between the total current and the horizontal arm.

[0017] This invention also discloses a method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure, comprising:

[0018] Step 1: A cross-shaped Hall bridge was fabricated on a clean AlGaN / GaN heterojunction 2DEGs sample using ultraviolet exposure technology; a layer of photoresist was spin-coated onto the surface of the clean sample, and then the pattern was exposed on an ultraviolet exposure machine. After exposure, development was performed.

[0019] Step 2: Remove the thin film outside the cross structure and remove the photoresist from the sample using inductively coupled plasma etching (ICP); form a cross pattern using ICP etching; after etching, immerse the sample in acetone, remove the photoresist, wash with deionized water, and dry with nitrogen.

[0020] Step 3: Prepare ohmic contact electrode patterns on the sample using ultraviolet exposure technology;

[0021] Step 4: Evaporate four layers of Ti / Al / Ni / Au metal as ohmic contact electrodes using electron beam evaporation technology, and remove the remaining photoresist on the sample; deposit ohmic electrode metal using electron beam evaporation, immerse the sample in acetone after deposition, sonicate, remove the photoresist, clean in deionized water, and dry with nitrogen.

[0022] Step 5: Perform rapid annealing on the sample using a rapid annealing furnace to form ohmic contact. The rapid annealing temperature is 850℃ and the annealing time is 30s.

[0023] Step 6: Evaporate Ti / Au metal using electron beam evaporation technology as a metal gate, the metal gate being a grating structure; deposit the metal grating electrode using electron beam evaporation, after metal deposition, immerse the sample in acetone, sonicate, remove the adhesive, clean in deionized water, and dry with nitrogen gas, thus completing the sample preparation.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0025] The present invention discloses a method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure. An AlGaN / GaN heterojunction is used as the source of 2DEGs, and a metal grating-type electrode structure is fabricated on it. A periodic grating electric field barrier is generated through a localized electric field effect. By studying the magnetoresistance effect of this system, a large magnetoresistance anisotropy is obtained, which can be tuned by the applied gate voltage.

[0026] This invention relates to a heterostructure combining a metal grating-type gate voltage electrode structure and semiconductor 2DEGs. By growing the metal grating electrode structure on a cross-shaped semiconductor heterojunction, significant planar electrical anisotropy under different current directions in a magnetic field can be achieved. The magnitude of the device's electrical anisotropy can be controlled in situ by changing the gate voltage. Furthermore, it provides an economical and practical method for designing in-planar electrically anisotropic devices. This method features simple microfabrication processes, can be extended to other two-dimensional material systems, and possesses advantages such as good versatility and the ability to mass-produce on large areas. Attached Figure Description

[0027] Figure 1 (a) is a schematic diagram of a periodic potential field that can be controlled in situ; (b) is an optical photograph of a Hall device sample with a cross structure; (c) is a polar coordinate diagram of R-θ under different gate voltages when there is no external magnetic field.

[0028] Figure 2 (a) in the text is V g (a) is the polar plot of R-θ under different magnetic fields when B = -4 V; (b) is the polar plot of R-θ under different grid voltages when B = 9 T.

[0029] Figure 3 The magnetoresistance of this invention at T = 1.8 K is shown in (a), (b) and (c) as test schematic diagrams; (d) and (e) are the MR-B relationship at zero gate voltage and with applied gate voltage, respectively; (f) is the MR-B curve for different current directions when gate voltage is applied.

[0030] Figure 4 (a) and (b) in the figure represent the relationship between the anisotropy factor and the gate voltage and magnetic field, respectively.

[0031] Figure 5 In the diagram, (a) and (b) represent V respectively. g (a) shows the MR-B curves at θ = 0° and θ = 90° at different temperatures when V = -4 V; (b) shows the MR-B curves at different temperatures when there is no gate voltage; (c) shows the MR-B curves at different temperatures when there is no gate voltage; (d) shows the MR-B curves at V = -4 V. g = -4 V Semi-log plot of temperature-dependent anisotropy factor AR;

[0032] Figure 6 (a) in the equation is R under B = 9T. T – θ polar coordinate plot; (b) is R under different magnetic fields T – Polar coordinate graph of θ. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0034] The present invention discloses an electrical anisotropy device based on a grating-type gate voltage structure. By setting a grating-type electrode structure on a heterojunction, an in-situ adjustable potential field is established, forming an artificial stripe phase electron channel, thereby realizing in-situ control of the lateral and longitudinal resistance of the lower 2DEGs. A huge positive magnetoresistance and negative magnetoresistance effect are achieved in two mutually perpendicular directions, thereby controlling huge electrical anisotropy.

[0035] By applying a gate voltage to the grating gate structure, an in-situ adjustable potential field is created. Then, an external magnetic field is applied; the stronger the magnetic field, the greater the anisotropy. The manipulation of the periodic potential field induces a large anisotropy in the magnetoresistance. When an external perpendicular magnetic field is applied, the strength of the gate voltage adjustment affects the anisotropy of the system. The anisotropy factor AR decreases exponentially with decreasing gate voltage; when the gate voltage is zero or positive, AR ≈ 1; as the magnetic field increases linearly, the AR value increases exponentially.

[0036] The method for fabricating an anisotropic electrical device based on a grating-type gate voltage structure according to the present invention includes the following steps:

[0037] Step 1: Prepare a cross-shaped Hall bridge pattern on a clean AlGaN / GaN heterojunction 2DEGs sample using ultraviolet light exposure.

[0038] A layer of AZ5214 photoresist was spin-coated onto the clean sample surface under the following conditions: 600 r / min for 5 s; 3000 r / min for 60 s. The sample was then baked on a 95 ℃ baking stage for 2 min, followed by pattern exposure on a UV exposure machine. After exposure, the sample was developed.

[0039] Step 2: Use ICP etching to remove the thin film outside the cross structure and remove the photoresist from the sample;

[0040] The etching parameters for forming the cross pattern using ICP etching were: gas flow rate Cl2 (43.2 sccm) / BCl3 (10.8 sccm), RF power (40 W) / ICP power (120 W), the etching rate was basically stable at 90 nm / min, the etching time was 40 s, and the etching depth was approximately 60 nm. After etching, the sample was placed in acetone for half an hour, sonicated, desizing, washed with deionized water, and dried with nitrogen.

[0041] Step 3: Prepare ohmic contact electrode patterns on the sample using ultraviolet exposure technology;

[0042] The ohmic contact electrode pattern was still prepared on the sample using ultraviolet exposure technology, and the preparation process and conditions were the same as in step 1.

[0043] Step 4: Evaporate the four metal layers Ti / Al / Ni / Au using electron beam evaporation technology to serve as ohmic contact electrodes, and remove any remaining photoresist from the sample;

[0044] Ohmic electrode metals were deposited by electron beam evaporation: the metal thicknesses were Ti (30 nm) / Al (150 nm) / Ni (50 nm) / Au (100 nm). After evaporation, the samples were immersed in acetone for half an hour, sonicated, desizing, washed in deionized water, and dried with nitrogen.

[0045] Step 5: Perform rapid annealing on the sample using a rapid annealing furnace to form ohmic contacts;

[0046] The samples were rapidly annealed using a rapid annealing furnace: the annealing temperature was 850℃ and the annealing time was 30s.

[0047] Step 6: Evaporate Ti / Au metal using electron beam evaporation technology as the metal gate.

[0048] The metal thicknesses were Ti (20 nm) and Au (100 nm). After vapor deposition, the samples were immersed in acetone for half an hour, sonicated, and after removing the adhesive, washed with deionized water and dried with nitrogen. The sample preparation was then complete. The final product resembled... Figure 1 The sample structure is shown.

[0049] The fabricated device, such as Figure 1 As shown: the two thicker arms of the cross structure serve as current electrodes with a width of W = 60 μm, and the metal at the top is a grating structure with a width of a = 5 μm and a spacing of b = 20 μm.

[0050] A schematic diagram of the test method is shown below. Figure 1 As shown in (b): Current I x = I total * cosθ and I y = I total *sinθ is injected from both ends of the Hall device. By writing a Python test program, two 6221 power meters are controlled to continuously change the magnitudes of the two currents, thereby obtaining a total value of I in the middle region of the cross-shaped Hall device. total = 100 μA vector current that can change direction 360°. This method for testing in-plane conductivity anisotropy has been verified and is feasible.

[0051] The corresponding voltage signals in different directions are tested through the four thinner electrodes at the corners, and then the longitudinal and lateral resistances can be obtained through the following calculations:

[0052] (1)

[0053] (2)

[0054] Where R is the longitudinal resistance, R T This is the lateral resistance, also known as the Hall resistor. V1 is the voltage measured parallel to the grating direction, V2 is the voltage measured perpendicular to the grating direction, and angle θ is the angle between the total current and the horizontal arm, defined as follows: Figure 1 As shown in (b) of the diagram.

[0055] By applying a voltage to the grating-type gate structure, a periodically adjustable potential field can be formed, such as... Figure 1 As shown in (a) in the figure: the experiment mainly focused on V g A grid voltage is applied to control the potential field. The relationship between the longitudinal resistance R and θ is measured without an external magnetic field, such as... Figure 1 As shown in (c), at zero gate voltage, the R − θ curve is relatively round, indicating that the 2DEGs in the heterojunction are relatively uniform and there is no obvious in-plane anisotropy. As the gate voltage increases from 0 V to -4 V, R shows a slow increasing trend in all current directions. This is because as the negative gate voltage increases, the carrier concentration below the gate gradually decreases, thus increasing the resistance. Simultaneously, an increasing anisotropy (double symmetry) is observed along the 0 − 180° direction in R. Here, the anisotropy factor AR = R is defined. max / R min R max and R min These are the maximum and minimum resistances measured by the rotating current, respectively. The magnitude of the sample's electrical anisotropy can be determined from the AR value. Under conditions of no external field but a gate voltage of V... g When the voltage is -4 V, the calculated AR value is 1.08, indicating that although the electrical anisotropy exists at this point, it is very weak.

[0056] We have already measured that the sample exhibits weak uniaxial anisotropy when no external field is applied but a gate voltage is applied. Next, we will test its transport properties in a magnetic field. Figure 2 (a) in the text is V g Polar graphs of R-θ under different magnetic fields at V = -4 V; Figure 2 (b) is the polar coordinate plot of R-θ under different gate voltages when B = 9 T.

[0057] from Figure 2As shown in (a), the uniaxial anisotropy of the sample becomes very significant when an external magnetic field is applied, and the anisotropy increases with the strength of the magnetic field. Near θ = 0° (180°), the longitudinal resistance increases exponentially with the magnetic field increasing from 0 to 9 T. Conversely, the resistance at θ = 90° (270°) decreases rapidly with increasing magnetic field. Figure 2 (b) in the figure is a polar plot of the longitudinal magnetoresistance R–θ for T = 1.8 K and B = 9 T under different gate voltage values. It can be seen that, under the condition of an applied vertical magnetic field, the strength of the gate voltage regulation will also greatly affect the electrical anisotropy of the system.

[0058] from Figure 2 It can be seen that the modulation of the periodic potential field causes a huge anisotropy in magnetoresistance. For further investigation, the gate voltage is fixed at V. g = -4 V (and compared with magnetoresistance data without any gate voltage), magnetoresistance curves were tested at different angles. All tests were performed in a superconducting cryogenic magnet testing system, with the magnetic field applied perpendicular to the 2DEGs plane, reaching a maximum of ± 9 T. Magnetoresistance MR is defined as (R − R0) / R0, where R0 is the longitudinal resistance at zero field. Test results are as follows: Figure 3 As shown, Figure 3 The magnetoresistance at T = 1.8 K is shown in (a), (b) and (c) as test schematic diagrams (black arrows represent different current directions); (d) and (e) are the MR-B relationship at zero gate voltage and with applied gate voltage, respectively; (f) is the MR-B curve for different current directions when gate voltage is applied.

[0059] The current direction is fixed at θ = 90° (i.e., the current is parallel to the direction of the grating electrodes, such as...). Figure 3 (a) and θ = 0° (the current is perpendicular to the direction of the grating electrode, such as...) Figure 3 (b) in the middle), the gate voltage is V g = -4 V for sweep field testing. At θ = 90°, compared to only -15% of the magnetoresistance without gate voltage, the negative magnetoresistance reaches -80% when a gate voltage is applied. Figure 3 (d)); while at θ = 0°, a positive magnetoresistance exceeding 1000% was observed, such as Figure 3 As shown in (e), the positive magnetoresistance shows no signs of saturation even at B = 9 T. Furthermore, detailed MR-B curves at different angles were obtained by continuously changing the current angle, as shown in... Figure 3 As shown in (f) in the diagram, the positive magnetoresistance decreases rapidly with increasing angle, and is almost zero at θ = 75°.

[0060] The anisotropy factor AR of electric transport was extracted as a function of magnetic field and gate voltage, such as... Figure 4 As shown, Figure 4 In the diagram, (a) and (b) show the relationship between the magnetic anisotropic factor and the grid voltage and magnetic field, respectively, and the dashed line is the trend line. Figure 4 In (a), AR changes with grid voltage when the magnetic field B = 9 T is fixed. It can be seen that AR decays exponentially as the grid voltage decreases, and AR ≈ 1 when the grid voltage is zero or positive. Figure 4 In (b), the fixed gate voltage is V. g At -4 V, AR changes with the magnetic field: as the magnetic field increases linearly, the AR value increases exponentially. Both results indicate that gate voltage modulation successfully forms a transport channel for 2DEGs, thus achieving a large in-plane anisotropy. Compared with the same in-plane anisotropy inherent in natural materials, such as the existing two-dimensional nonmagnetic semiconductor PdSe2 (calculated AR is approximately 3.13), the modulation degree of this invention is very advantageous.

[0061] The requirement for electrical anisotropy in devices is not only reflected in the degree of anisotropy control, but also in their performance at different temperatures, especially at higher temperatures. The MR-B curves were tested at different temperatures (θ = 0° and θ = 90°) with a fixed gate voltage of V. g = -4 V), such as Figure 5 (a) and Figure 5 As shown in (b) above. To compare the magnetoresistance effect caused by the absence of a gate voltage, MR-B curves at different temperatures were also tested under conditions without a gate voltage, as shown below. Figure 5 As shown in (c) in the figure, Figure 5 In the example, (a) and (b) are V g = -4 V, MR-B curves at θ = 0° (a) and MR-B curves at θ = 90° measured at different temperatures; Figure 5 (b) and (c) are the MR-B curves measured at different temperatures without a gate voltage. Figure 5 (d) in V g Semi-log plot of temperature-dependent anisotropy factor AR at -4 V.

[0062] It can be seen that at T = 1.8 K, the magnetoresistance without grid voltage exhibits a negative parabolic curve under moderate magnetic fields, and shows significant SdH oscillations under higher magnetic fields. Meanwhile, the negative magnetoresistance effect gradually weakens with increasing temperature, eventually approaching zero magnetoresistance at a high temperature of T = 180 ℃. In contrast, the SdH oscillations at θ = 90° and θ = 0° are significantly suppressed; on the other hand, although the large negative and positive magnetoresistance effects at θ = 90° and θ = 0° weaken with increasing temperature, the weakening is relatively slow, as... Figure 5 In Figure (d), AR varies with temperature. It can be seen that AR decays exponentially with increasing temperature, but even at higher temperatures (T = 250 K, AR = 4), it still maintains a large anisotropic magnetoresistance effect.

[0063] According to formula (2), the transverse resistance data can also be obtained during the test, such as... Figure 6 (a) shows the different gate voltages (here, the gate voltage is still V). g = -4 V ~ 0 V), transverse resistance R when B = 9 T T – Polar coordinate relationship diagram. Unlike the uniaxial anisotropy of the longitudinal resistance R, R… T The anisotropy direction shifted by 45°, with the maximum anisotropy occurring at 135° (315°). Similarly, R... T The anisotropy of R also gradually increases with the increase of the gate voltage; when the direction of the magnetic field changes, T The directions of anisotropy are also opposite, such as Figure 6 In (b), when the magnetic field is negative, the maximum anisotropy occurs at 45° (225°).

[0064] This invention establishes an in-situ tunable potential field by designing a grating-type gate voltage electrode structure on an AlGaN / GaN heterojunction, forming a typical artificial "striped phase" electron channel, thus achieving in-situ control of the lateral and longitudinal resistances of the underlying 2DEGs. Large positive and negative magnetoresistance effects were observed in two mutually perpendicular directions, successfully generating significant electrical anisotropy, which is maintained over a wide temperature range. This work provides a simple and effective new approach for realizing in-situ tunable in-plane electrical anisotropy electronic devices.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electrical anisotropic device based on a grating-type gate voltage structure, characterized in that: By setting a grating-type gate voltage structure on the cross-shaped AlGaN / GaN heterojunction, a cross-shaped Hall device is obtained; an in-situ adjustable potential field is established to form an artificial stripe phase electron channel, thereby realizing in-situ control of the transverse and longitudinal resistance of the lower two-dimensional electron gas; huge positive and negative magnetoresistance effects are achieved in two mutually perpendicular directions, thereby controlling huge electrical anisotropy.

2. The electrical anisotropic device based on a grating-type gate voltage structure according to claim 1, characterized in that: By applying a variable gate voltage to the grating-type gate voltage structure V g This creates an in-situ adjustable electric potential field. Then, an external magnetic field is applied. The larger the magnetic field, the greater the electrical anisotropy. The regulation of the periodic electric potential field causes a huge anisotropy in the magnetoresistance.

3. The electrical anisotropic device based on a grating-type gate voltage structure according to claim 2, characterized in that: When an external vertical magnetic field is applied, the strength of the gate voltage regulation affects the electrical anisotropy of the system.

4. The electrical anisotropic device based on a grating-type gate voltage structure according to claim 2, characterized in that: Anisotropic factors AR The decay is exponential as the gate voltage decreases, and it decreases when the gate voltage is zero or positive. AR ≈ 1; as the magnetic field increases linearly, AR The value increases exponentially.

5. The electrical anisotropic device based on a grating-type gate voltage structure according to claim 1, characterized in that: The method for testing in-plane conductivity anisotropy is as follows: Current I x = I total * cos θ and I y = I total sin θ By injecting current from both ends of the Hall effect device, two power meters are controlled, continuously changing the magnitudes of the two currents, thus obtaining a total value in the middle region of the cross-shaped Hall effect device. I total It is also a vector current that can change direction 360°.

6. The electrical anisotropic device based on a grating-type gate voltage structure according to claim 1, characterized in that: The methods for testing the longitudinal and lateral resistance are as follows: The corresponding voltage signals in different directions are tested through the electrodes at the four corners. The longitudinal and lateral resistances are calculated using the following formula: ； ； in, R It is the longitudinal resistance. R T It is a lateral resistance. V 1 is the voltage measured parallel to the grating direction. V 2 is the voltage measured perpendicular to the grating direction. I It's electric current, angle. θ It is the angle between the total current and the horizontal arm.

7. A method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure as described in any one of claims 1-6, characterized in that, include: Step 1: Fabricate a cross-shaped Hall bridge on a clean AlGaN / GaN heterojunction two-dimensional electron gas sample using ultraviolet exposure technology; A layer of photoresist is spin-coated onto the surface of a clean sample, and then the pattern is exposed on a UV exposure machine. After exposure, development is performed. Step 2: Use inductively coupled plasma etching to remove the thin film outside the cross structure and remove the photoresist from the sample; A cross pattern was formed by inductively coupled plasma etching. After etching, the sample was immersed in acetone, removed from the resist, washed in deionized water, and dried with nitrogen. Step 3: Prepare ohmic contact electrode patterns on the sample using ultraviolet exposure technology; Step 4: Evaporate four layers of metal, Ti / Al / Ni / Au, to serve as ohmic contact electrodes, and remove any remaining photoresist from the sample; Step 5: Perform rapid annealing on the sample using a rapid annealing furnace to form ohmic contacts; Step 6: Evaporate Ti / Au metal as the metal gate, and the metal gate is a grating-type gate voltage structure.

8. The method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure according to claim 7, characterized in that: In step 4, ohmic contact electrodes are deposited by electron beam evaporation. After evaporation, the sample is immersed in acetone, sonicated, desizing, cleaned in deionized water, and dried with nitrogen.

9. The method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure according to claim 7, characterized in that: In step 5, the sample is rapidly annealed using a rapid annealing furnace: the annealing temperature is 850℃ and the annealing time is 30s.

10. The method for fabricating an electrically anisotropic device based on a grating-type gate voltage structure according to claim 7, characterized in that: In step 6, the metal gate is deposited by electron beam evaporation. After evaporation, the sample is immersed in acetone, sonicated, and after removing the adhesive, it is cleaned in deionized water and dried with nitrogen. The sample preparation is then complete.

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