A lateral gallium oxide high voltage Schottky diode and its preparation method

Abstract

The invention discloses a lateral gallium oxide high-voltage Schottky diode and a preparation method thereof, belonging to the technical field of semiconductor materials and devices; the lateral gallium oxide high-voltage Schottky diode comprises a gallium oxide substrate; at least two trapezoidal through holes are provided on the gallium oxide substrate, the upper bottom of the trapezoidal through holes is located on the front of the gallium oxide substrate, and the lower bottom of the trapezoidal through holes is located on the back of the gallium oxide substrate; a silicon nitride dielectric layer is deposited on the back of the gallium oxide substrate; a Ti metal layer, a first chemically inert metal layer, a Ni metal layer and a second chemically inert metal layer are deposited on the front of the gallium oxide substrate; the Ni metal layer and the second chemically inert metal layer are located on the surface of the gallium oxide substrate between the two trapezoidal through holes; the Ti metal layer and the first chemically inert metal layer are located on the surface of the gallium oxide substrate outside the two trapezoidal through holes. The diode structure prepared by the invention has good electrical characteristics and better voltage resistance than the gallium oxide Schottky diode in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials and devices, and relates to a lateral gallium oxide high-voltage Schottky diode and a preparation method thereof. Background Art

[0002] With the rise of a new generation of communication technology, the requirements for data transmission rate, bandwidth and latency are getting higher and higher. Ultra-high power and ultra-high frequency electronic devices are the cornerstones supporting the rapid development of modern communication technology. They can provide higher operating frequencies and faster signal processing capabilities to meet these stringent technical requirements and promote the continuous leap of communication technology.

[0003] As the fourth generation of ultra-wide bandgap semiconductor materials, gallium oxide has the characteristics of ultra-wide bandgap width, high breakdown field strength, high throw and drift rate, making it an ideal material for preparing ultra-high power and ultra-high frequency electronic devices. As a key component in the application of gallium oxide-based electronic devices, Schottky diodes play a key role in the circuit's current density, operating temperature, high power performance and other parameters.

[0004] At present, gallium oxide Schottky diodes usually face the disadvantage of insufficient breakdown voltage, and low voltage breakdown often occurs during testing. The above shortcomings directly lead to the reduction of the overall performance of Schottky diodes, limiting their application scope and environment. Summary of the invention

[0005] The object of the present invention is to provide a lateral gallium oxide high voltage Schottky diode and a preparation method thereof, so as to solve the technical problem of poor withstand voltage characteristics of gallium oxide Schottky diodes in the prior art.

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

[0007] In a first aspect, the present invention provides a lateral gallium oxide high-voltage Schottky diode, comprising a gallium oxide substrate; at least two trapezoidal through holes are opened on the gallium oxide substrate, the upper bottom of the trapezoidal through holes is located on the front side of the gallium oxide substrate, and the lower bottom of the trapezoidal through holes is located on the back side of the gallium oxide substrate; a silicon nitride dielectric layer is deposited on the back side of the gallium oxide substrate; a Ti metal layer, a first chemically inert metal layer, a Ni metal layer and a second chemically inert metal layer are deposited on the front side of the gallium oxide substrate; the Ni metal layer is located on the surface of the gallium oxide substrate between the two trapezoidal through holes, and the second chemically inert metal layer is located on the Ni metal layer; the Ti metal layer is located on the surface of the gallium oxide substrate outside the two trapezoidal through holes, and the first chemically inert metal layer is located on the Ti metal layer.

[0008] Furthermore, the gallium oxide substrate has a doping concentration of 10 16 cm –3 ~10 17cm –3 The N-type doped gallium oxide film has a gallium oxide substrate thickness of 10 microns to 500 microns.

[0009] Furthermore, the first chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd; and the second chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

[0010] In a second aspect, the present invention provides a method for preparing the above-mentioned lateral gallium oxide high-voltage Schottky diode, comprising the following steps:

[0011] The gallium oxide surface is cleaned to remove the non-gallium oxide phase on the gallium oxide surface, and the gallium oxide is punched with a laser device to form a trapezoidal through hole to obtain a gallium oxide substrate;

[0012] A layer of photoresist is spin-coated on the back of the gallium oxide substrate and in the trapezoidal through hole, and then an electron beam evaporation device is used to deposit a layer of aluminum metal film on the front of the gallium oxide substrate. After the deposition is completed, the photoresist is removed to obtain a gallium oxide substrate with an aluminum metal film;

[0013] Depositing a silicon nitride film on the back of the gallium oxide substrate with the aluminum metal film, and then removing the aluminum metal film on the front side with a dilute hydrochloric acid solution to obtain a gallium oxide substrate with the silicon nitride film;

[0014] A layer of photoresist is spin-coated on the front side of the gallium oxide substrate with the silicon nitride film and patterned, and then a Ti metal layer and a first chemically inert metal layer are sequentially deposited on the front side of the gallium oxide substrate using an electron beam evaporation device, and after the deposition is completed, the photoresist is removed and an annealing treatment is performed;

[0015] A layer of photoresist is spin-coated on the front side of the annealed gallium oxide substrate and patterned, and then an electron beam evaporation device is used to sequentially deposit a Ni metal layer and a second chemically inert metal layer on the front side of the gallium oxide substrate. After the deposition is completed, the photoresist is removed to obtain a lateral gallium oxide high-voltage Schottky diode.

[0016] Furthermore, the thickness of the aluminum metal film is 20nm~200nm; the thickness of the silicon nitride film is 20nm~200nm; the thickness of the Ti metal layer is 20nm~50nm; the thickness of the first chemically inert metal layer is 80nm~150nm; the thickness of the Ni metal layer is 20nm~50nm; the thickness of the second chemically inert metal layer is 80nm~150nm.

[0017] Furthermore, the step of removing the photoresist specifically includes: immersing the gallium oxide substrate in acetone or N-methylpyrrolidone solution and performing water bath heating or ultrasonic treatment.

[0018] Furthermore, the annealing treatment is performed in a nitrogen atmosphere, an argon atmosphere or a hydrogen atmosphere, the annealing temperature is 450° C., and the annealing time is 1 min.

[0019] Furthermore, the step of cleaning the surface of gallium oxide specifically includes: treating the gallium oxide material substrate with a mixed solution of sulfuric acid and hydrogen peroxide in a water bath at 200° C. for 15 minutes; the volume ratio of sulfuric acid to hydrogen peroxide is 3:1.

[0020] Furthermore, when the aluminum metal film, the Ti metal layer, the first chemically inert metal layer, the Ni metal layer and the second chemically inert metal layer are deposited respectively, the vacuum degree is less than 5×10 -5 Pa at room temperature.

[0021] Furthermore, the step of depositing the silicon nitride film specifically includes: using NH3 and SiH4 to deposit the silicon nitride film on the back side of the gallium oxide substrate with an aluminum metal film, the deposition temperature is 450°C, the deposition time is 720 seconds, the gas flow rate is 4320sccm, and the pressure is 170Pa; the volume ratio of NH3 and SiH4 is 8:1.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a lateral gallium oxide high-voltage Schottky diode and a preparation method thereof, wherein a patterned trapezoidal structure is formed by using a laser to act and penetrate on the back of a gallium oxide substrate, a silicon nitride dielectric layer is deposited on the back of the gallium oxide substrate; a Ti metal layer and a first chemically inert metal layer are then patterned deposited on the front of the gallium oxide substrate, and the gallium oxide-based ohmic contact structure is formed by rapid annealing; finally, a Ni metal layer and a second chemically inert metal layer are patterned deposited on the front of the gallium oxide substrate, and the high-voltage gallium oxide-based Schottky diode structure is finally formed. The gallium oxide-based Schottky diode structure prepared by the present invention has good electrical characteristics and better voltage resistance than the gallium oxide Schottky diode in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is a flow chart of the preparation process of an embodiment of the present invention;

[0026] Figure 2This is a schematic diagram of the structure of a lateral gallium oxide high-voltage Schottky diode prepared in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible sub-ranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0031] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0033] See also Figure 2The embodiment of the present invention discloses a lateral gallium oxide high-voltage Schottky diode, comprising a gallium oxide substrate; at least two trapezoidal through holes are opened on the gallium oxide substrate, the upper bottom of the trapezoidal through holes is located on the front side of the gallium oxide substrate, and the lower bottom of the trapezoidal through holes is located on the back side of the gallium oxide substrate; a silicon nitride dielectric layer is deposited on the back side of the gallium oxide substrate; a Ti metal layer, a first chemically inert metal layer, a Ni metal layer and a second chemically inert metal layer are deposited on the front side of the gallium oxide substrate; the Ni metal layer is located on the surface of the gallium oxide substrate between the two trapezoidal through holes, and the second chemically inert metal layer is located on the Ni metal layer; the Ti metal layer is located on the surface of the gallium oxide substrate outside the two trapezoidal through holes, and the first chemically inert metal layer is located on the Ti metal layer.

[0034] In a feasible embodiment of the present invention, the gallium oxide substrate has a doping concentration of 10 16 cm –3 ~10 17 cm –3 The N-type doped gallium oxide film has a gallium oxide substrate thickness of 10 microns to 500 microns. The first chemically inert metal layer uses one or more of Au, W, Ir, Pt and Pd, but is not limited to; the second chemically inert metal layer uses one or more of Au, W, Ir, Pt and Pd.

[0035] See also Figure 1 The embodiment of the present invention discloses a method for preparing the above-mentioned lateral gallium oxide high-voltage Schottky diode, comprising the following steps:

[0036] S1, cleaning the surface of gallium oxide to remove the non-gallium oxide phase on the surface of gallium oxide, and drilling the gallium oxide with a laser device to form a trapezoidal through hole to obtain a gallium oxide substrate;

[0037] In this step, the gallium oxide material substrate is treated with a mixed solution of sulfuric acid and hydrogen peroxide in a water bath at 200°C for 15 minutes; the volume ratio of sulfuric acid to hydrogen peroxide is 3:1. The vertical cross-section of the laser hole is a trapezoid, and the angle between the hypotenuse of the trapezoid and the front of the gallium oxide must be greater than 90 degrees. The area between the two trapezoidal through holes on the front of the gallium oxide is the gallium oxide surface. If it is needed to prepare the Schottky pole of the gallium oxide Schottky diode, the distance between the two trapezoidal through holes on the front of the gallium oxide can be in the range of 50 microns to 240 microns.

[0038] S2, spin coating a layer of photoresist on the back side of the gallium oxide substrate and in the trapezoidal through hole, and then depositing a layer of aluminum metal film on the front side of the gallium oxide substrate by electron beam evaporation equipment, and removing the photoresist after the deposition is completed to obtain a gallium oxide substrate with an aluminum metal film;

[0039] In this step, the thickness of the aluminum metal film is 20 nm to 200 nm; the gallium oxide sample is immersed in acetone or N-methylpyrrolidone solution and then heated in a water bath or subjected to ultrasonic treatment to remove the photoresist;

[0040] S3, depositing a silicon nitride film on the back side of the gallium oxide substrate with the aluminum metal film, and then removing the aluminum metal film on the front side with a dilute hydrochloric acid solution to obtain a gallium oxide substrate with a silicon nitride film;

[0041] In this step, the thickness of the silicon nitride film is 20nm to 200nm; the steps of depositing the silicon nitride film are specifically as follows: placing the gallium oxide material substrate in the PECVD equipment to deposit silicon nitride on the back side, and the experimental conditions are: 450 degrees, the volume ratio of NH3 and SiH4 is 8:1, the gas flow rate is 4320sccm, the pressure is 170Pa, and the deposition time is 720 seconds.

[0042] S4, spin-coating a layer of photoresist on the front side of the gallium oxide substrate with the silicon nitride film and performing patterning, then using an electron beam evaporation device to sequentially deposit a Ti metal layer and a first chemically inert metal layer with poor mutual diffusion on the front side of the gallium oxide substrate, removing the photoresist after the deposition is completed and performing annealing to improve the reliability of the ohmic contact;

[0043] In this step, the thickness of the Ti metal layer is 20nm-50nm; the thickness of the first chemically inert metal layer is 80nm-150nm; the annealing treatment is carried out in a nitrogen atmosphere, an argon atmosphere or a hydrogen atmosphere, the annealing temperature is 450°C, and the annealing time is 1 minute.

[0044] S5, spin-coating a layer of photoresist on the front side of the annealed gallium oxide substrate and performing patterning, and then using electron beam evaporation equipment to sequentially deposit a Ni metal layer and a second chemically inert metal layer on the front side of the gallium oxide substrate, wherein the area of ​​the Ni metal layer is slightly larger than the range of the trapezoidal upper surface of the gallium oxide substrate surface; after the deposition is completed, the photoresist is removed to obtain a lateral gallium oxide high-voltage Schottky diode.

[0045] In this step, the thickness of the Ni metal layer is 20 nm to 50 nm; the thickness of the second chemically inert metal layer is 80 nm to 150 nm.

[0046] The present invention will be further described below in conjunction with specific embodiments. 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. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0047] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0048] Embodiment 1:

[0049] 1) In a 200°C water bath, the gallium oxide material substrate was treated with a mixed solution of sulfuric acid and hydrogen peroxide in a volume ratio of 3:1 for 15 minutes;

[0050] 2) placing the gallium oxide material in a laser device, and drilling holes from the back side of the gallium oxide to the front side, forming a trapezoidal structure in which the hole size on the back side is larger than that on the front side, the angle between the hypotenuse of the trapezoid in the vertical cross section and the front side of the gallium oxide is 120 degrees, and the trapezoidal hole on the front side of the gallium oxide is a rectangle with a side length of 50 microns × 70 microns;

[0051] 3) Use alcohol, acetone, isopropanol and deionized water to heat the sample in a water bath and ultrasonically clean it for 5 minutes;

[0052] 4) Spin-coating a layer of photoresist on the back of the gallium oxide to cover the entire back area, including the existing trapezoidal holes;

[0053] 5) Placing the gallium oxide material substrate in an electron beam evaporation device to perform metal coating on the front side. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and deposition of 100nm of Al;

[0054] 6) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in an 80°C water bath to remove the photoresist produced by the photolithography technology;

[0055] 7) Place the gallium oxide material substrate in a PECVD device and deposit silicon nitride on the back side. The experimental conditions are: 450 degrees, NH3 / SiH4=8:1, gas flow rate 4320sccm, pressure 170Pa, deposition time 720 seconds, and silicon nitride film thickness 100nm;

[0056] 8) Place the sample in a dilute hydrochloric acid solution to remove the aluminum metal film on the surface;

[0057] 9) Spin-coating a layer of photoresist on the front side of gallium oxide and forming the required design pattern using photolithography technology;

[0058] 10) placing the sample in an electron beam evaporation device, depositing a first electrode Ti metal layer of 20 nm on the front side of the gallium oxide substrate, and then depositing a first chemically inert metal layer of Au of 80 nm with poor interdiffusion;

[0059] 11) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology;

[0060] 12) After the deposition is completed, the gallium oxide sample is annealed at a temperature of 450° C. for 60 seconds;

[0061] 13) Using photolithography technology, transfer the pattern on the mask to the upper layer of the front side of the gallium oxide;

[0062] 14) Placing the gallium oxide substrate with the mask pattern facing upward in an electron beam evaporation device for metal coating. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and depositing 20nm of Ni and 100nm of Au in sequence;

[0063] 15) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology, thereby obtaining a lateral gallium oxide high-voltage Schottky diode.

[0064] Embodiment 2:

[0065] 1) In a 200°C water bath, the gallium oxide material substrate was treated with a mixed solution of sulfuric acid and hydrogen peroxide in a volume ratio of 3:1 for 15 minutes;

[0066] 2) placing the gallium oxide material in a laser device, and drilling holes from the back side of the gallium oxide to the front side, forming a trapezoidal structure in which the hole size on the back side is larger than that on the front side, the angle between the hypotenuse of the trapezoid in the vertical cross section and the front side of the gallium oxide is 120 degrees, and the trapezoidal hole on the front side of the gallium oxide is a rectangle with a side length of 50 microns × 70 microns;

[0067] 3) Use alcohol, acetone, isopropanol and deionized water to heat the sample in a water bath and ultrasonically clean it for 5 minutes;

[0068] 4) Spin-coating a layer of photoresist on the back of the gallium oxide to cover the entire back area, including the existing trapezoidal holes;

[0069] 5) Placing the gallium oxide material substrate in an electron beam evaporation device to perform metal coating on the front side. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and deposition of 50nm of Al;

[0070] 6) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in an 80°C water bath to remove the photoresist produced by the photolithography technology;

[0071] 7) Place the gallium oxide material substrate in a PECVD device and deposit silicon nitride on the back side. The experimental conditions are: 450 degrees, NH3 / SiH4=8:1, gas flow rate 4320sccm, pressure 170Pa, deposition time 720 seconds, and silicon nitride film thickness 50nm;

[0072] 8) Place the sample in a dilute hydrochloric acid solution to remove the aluminum metal film on the surface;

[0073] 9) Spin-coating a layer of photoresist on the front side of gallium oxide and forming the required design pattern using photolithography technology;

[0074] 10) placing the sample in an electron beam evaporation device, depositing a first electrode Ti metal layer of 30 nm on the front side of the gallium oxide substrate, and then depositing a first chemically inert metal layer Pt of 100 nm with poor interdiffusion;

[0075] 11) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology;

[0076] 12) After the deposition is completed, the gallium oxide sample is annealed at a temperature of 450° C. for 60 seconds;

[0077] 13) Using photolithography technology, transfer the pattern on the mask to the upper layer of the front side of the gallium oxide;

[0078] 14) Placing the gallium oxide substrate with the mask pattern facing up in an electron beam evaporation device for metal coating. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and depositing 30nm of Ni and 80nm of Pt in sequence;

[0079] 15) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology, thereby obtaining a lateral gallium oxide high-voltage Schottky diode.

[0080] Embodiment 3:

[0081] 1) In a 200°C water bath, the gallium oxide material substrate was treated with a mixed solution of sulfuric acid and hydrogen peroxide in a volume ratio of 3:1 for 15 minutes;

[0082] 2) placing the gallium oxide material in a laser device, and drilling holes from the back side of the gallium oxide to the front side, forming a trapezoidal structure in which the hole size on the back side is larger than that on the front side, the angle between the hypotenuse of the trapezoid in the vertical cross section and the front side of the gallium oxide is 120 degrees, and the trapezoidal hole on the front side of the gallium oxide is a rectangle with a side length of 50 microns × 70 microns;

[0083] 3) Use alcohol, acetone, isopropanol and deionized water to heat the sample in a water bath and ultrasonically clean it for 5 minutes;

[0084] 4) Spin-coating a layer of photoresist on the back of the gallium oxide to cover the entire back area, including the existing trapezoidal holes;

[0085] 5) Placing the gallium oxide material substrate in an electron beam evaporation device to perform metal coating on the front side. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and depositing 160nm of Al;

[0086] 6) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in an 80°C water bath to remove the photoresist produced by the photolithography technology;

[0087] 7) Placing the gallium oxide material substrate in a PECVD device to deposit silicon nitride on the back side, the experimental conditions are: 450 degrees, NH3 / SiH4=8:1, gas flow rate 4320sccm, pressure 170Pa, deposition time 720 seconds, silicon nitride film thickness 160nm;

[0088] 8) Place the sample in a dilute hydrochloric acid solution to remove the aluminum metal film on the surface;

[0089] 9) Spin-coating a layer of photoresist on the front side of gallium oxide and forming the required design pattern using photolithography technology;

[0090] 10) placing the sample in an electron beam evaporation device, depositing a first electrode Ti metal layer of 40 nm on the front side of the gallium oxide substrate, and then depositing a first chemically inert metal layer Pd of 120 nm with poor interdiffusion;

[0091] 11) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology;

[0092] 12) After the deposition is completed, the gallium oxide sample is annealed at a temperature of 450° C. for 60 seconds;

[0093] 13) Using photolithography technology, transfer the pattern on the mask to the upper layer of the front side of the gallium oxide;

[0094] 14) Placing the gallium oxide substrate with the mask pattern facing up in an electron beam evaporation device for metal coating. The experimental conditions are: room temperature, vacuum degree less than 5×10-5Pa, and depositing 40nm of Ni and 120nm of Pd in ​​sequence;

[0095] 15) After the coating is completed, the gallium oxide sample is immersed in acetone and stripped in a water bath at 80° C. to remove the photoresist produced by the photolithography technology, thereby obtaining a lateral gallium oxide high-voltage Schottky diode.

[0096] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A lateral gallium oxide high voltage Schottky diode, characterized in that: The invention comprises a gallium oxide substrate; at least two trapezoidal through holes are formed on the gallium oxide substrate, the upper bottom of the trapezoidal through holes is located on the front side of the gallium oxide substrate, and the lower bottom of the trapezoidal through holes is located on the back side of the gallium oxide substrate; a silicon nitride dielectric layer is deposited on the back side of the gallium oxide substrate; a Ti metal layer, a first chemically inert metal layer, a Ni metal layer and a second chemically inert metal layer are deposited on the front side of the gallium oxide substrate; the Ni metal layer is located on the surface of the gallium oxide substrate between the two trapezoidal through holes, and the second chemically inert metal layer is located on the Ni metal layer; the Ti metal layer is located on the surface of the gallium oxide substrate outside the two trapezoidal through holes, and the first chemically inert metal layer is located on the Ti metal layer.

2. A lateral gallium oxide high voltage Schottky diode according to claim 1, characterized in that: The gallium oxide substrate has a doping concentration of 10 16 cm –3 ~10 17 cm –3 The N-type doped gallium oxide film has a gallium oxide substrate thickness of 10 microns to 500 microns.

3. A lateral gallium oxide high voltage Schottky diode according to claim 1, characterized in that: The first chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd; the second chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

4. A method for preparing a lateral gallium oxide high voltage Schottky diode according to any one of claims 1 to 3, characterized in that: The following steps are involved: The gallium oxide surface is cleaned to remove the non-gallium oxide phase on the gallium oxide surface, and the gallium oxide is punched with a laser device to form a trapezoidal through hole to obtain a gallium oxide substrate; A layer of photoresist is spin-coated on the back of the gallium oxide substrate and in the trapezoidal through hole, and then an electron beam evaporation device is used to deposit a layer of aluminum metal film on the front of the gallium oxide substrate. After the deposition is completed, the photoresist is removed to obtain a gallium oxide substrate with an aluminum metal film; Depositing a silicon nitride film on the back of the gallium oxide substrate with the aluminum metal film, and then removing the aluminum metal film on the front side with a dilute hydrochloric acid solution to obtain a gallium oxide substrate with the silicon nitride film; A layer of photoresist is spin-coated on the front side of the gallium oxide substrate with the silicon nitride film and patterned, and then a Ti metal layer and a first chemically inert metal layer are sequentially deposited on the front side of the gallium oxide substrate using an electron beam evaporation device, and after the deposition is completed, the photoresist is removed and an annealing treatment is performed; A layer of photoresist is spin-coated on the front side of the annealed gallium oxide substrate and patterned, and then an electron beam evaporation device is used to sequentially deposit a Ni metal layer and a second chemically inert metal layer on the front side of the gallium oxide substrate. After the deposition is completed, the photoresist is removed to obtain a lateral gallium oxide high-voltage Schottky diode.

5. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: The thickness of the aluminum metal film is 20nm to 200nm; the thickness of the silicon nitride film is 20nm to 200nm; the thickness of the Ti metal layer is 20nm to 50nm; the thickness of the first chemically inert metal layer is 80nm to 150nm; the thickness of the Ni metal layer is 20nm to 50nm; and the thickness of the second chemically inert metal layer is 80nm to 150nm.

6. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: The step of removing the photoresist specifically includes: immersing the gallium oxide substrate in acetone or N-methylpyrrolidone solution and performing water bath heating or ultrasonic treatment.

7. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: The annealing treatment is performed in a nitrogen atmosphere, an argon atmosphere or a hydrogen atmosphere, the annealing temperature is 450° C., and the annealing time is 1 minute.

8. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: The step of cleaning the surface of gallium oxide specifically includes: treating the gallium oxide material substrate with a mixed solution of sulfuric acid and hydrogen peroxide in a water bath at 200° C. for 15 minutes; the volume ratio of sulfuric acid to hydrogen peroxide is 3:

1.

9. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: When the aluminum metal film, the Ti metal layer, the first chemically inert metal layer, the Ni metal layer and the second chemically inert metal layer are deposited respectively, the vacuum degree is less than 5×10 -5 Pa at room temperature.

10. The method for preparing a lateral gallium oxide high voltage Schottky diode according to claim 4, characterized in that: The step of depositing the silicon nitride film specifically includes: using NH3 and SiH4 to deposit the silicon nitride film on the back of the gallium oxide substrate with an aluminum metal film, the deposition temperature is 450°C, the deposition time is 720 seconds, the gas flow rate is 4320sccm, and the pressure is 170Pa; the volume ratio of NH3 and SiH4 is 8:1.

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