High-voltage gallium oxide lateral Schottky barrier diode realized using resistive field plate technology

Abstract

The present invention provides a high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology. A dielectric layer isolates the resistive field plate layer from the N-type gallium oxide epitaxial layer to ensure that current does not flow from the semiconductor through the resistive field plate layer to the anode, thereby ensuring uniform current flow on the resistive field plate. Due to the high resistivity of the resistive field plate layer, when the voltage-resistant region withstands reverse voltage, a weak current flows through the resistive field plate, generating a uniform potential distribution along the current path. This modulates the surface electric field distribution in the semiconductor, resulting in a uniform surface electric field distribution and increasing the reverse breakdown voltage. The resistive field plate layer is prepared by depositing a nickel oxide thin film using magnetron sputtering technology, and regulating parameters in the magnetron sputtering, including RF power, RF temperature, RF argon-oxygen ratio, and RF pressure, to achieve a high-resistance nickel oxide thin film with uniform resistivity.

Description

Technical Field

[0001] The present invention belongs to the field of power semiconductor technology, and specifically relates to a high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology, that is, a gallium oxide lateral Schottky barrier diode (LSBD) implemented using resistive field plate technology and a preparation method thereof. Background Art

[0002] Lateral power devices share the reverse bias voltage through their lateral and longitudinal voltage-withstand structures. When the electric field peak in one section reaches the critical breakdown field, the device breaks down. However, because lateral power devices are affected by the surface field of the drift region, the surface field reaches the critical breakdown field before the longitudinal field. Consequently, lateral power devices have lower voltage withstand capability than vertical power devices. Resistive field plate technology improves the voltage withstand capability of gallium oxide lateral Schottky barrier diodes by modulating the surface electric field in the voltage-withstand region and optimizing the electric field peak.

[0003] Improving the withstand voltage of gallium oxide lateral Schottky barrier diodes using resistive field plate technology requires a semi-insulating film to regulate the electric field. However, since the semi-insulating film required for the resistive field plate must withstand a high critical breakdown electric field while also having a high and uniform resistivity, the selection and growth of the resistive field plate semi-insulating film material to ensure its effectiveness in gallium oxide lateral Schottky barrier diodes has become a challenge. Summary of the Invention

[0004] In response to the above-mentioned problems, the present invention proposes a high-voltage gallium oxide lateral Schottky barrier diode and its preparation method realized by resistive field plate technology. First, a dielectric layer is used to isolate the resistive field plate layer from the N-type gallium oxide epitaxial layer to ensure that the current does not flow from the semiconductor to the anode through the resistive field plate layer, so that the current on the resistive field plate is uniform and the electric field along the resistive field plate is also uniform. Then, a nickel oxide film is deposited by magnetron sputtering technology. Experimental parameters such as RF power, RF temperature, RF argon-oxygen ratio, and RF pressure in the magnetron sputtering are controlled to achieve a high-resistance nickel oxide film with uniform resistivity, thereby acting as a resistive field plate. Finally, with the help of the resistive field plate technology, when the voltage-resistant area is reversely withstand voltage, a weak current flows through the resistive field plate. According to the principle of current continuity, a uniform potential distribution is generated along the current path, which can modulate the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed, so that the device can withstand a higher reverse breakdown voltage.

[0005] The technical solution specifically adopted by the present invention to solve the technical problem is:

[0006] A high-voltage gallium oxide lateral Schottky barrier diode realized using resistive field plate technology

[0007] The resistive field plate layer and the N-type gallium oxide epitaxial layer are isolated by a dielectric layer to ensure that the current does not flow from the semiconductor to the anode through the resistive field plate layer, so that the current on the resistive field plate is uniform;

[0008] Due to the high resistivity of the resistive field plate layer, when the voltage-withstanding region withstands reverse voltage, a weak current flows through the resistive field plate, generating a uniform potential distribution along the current path, thereby modulating the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed, thereby increasing the reverse breakdown voltage.

[0009] Furthermore, the resistive field plate layer is prepared by depositing a nickel oxide film by magnetron sputtering technology, and regulating the parameters of the magnetron sputtering, including radio frequency power, radio frequency temperature, radio frequency argon-oxygen ratio, and radio frequency gas pressure, to achieve a high-resistance nickel oxide film with uniform resistivity.

[0010] Furthermore, the present invention comprises a substrate (1), an unintentionally doped layer (2), an N-type gallium oxide epitaxial layer (3), a dielectric layer (4), a resistive field plate layer (5), an anode and an anode stepped field plate layer (6), a cathode and a cathode stepped field plate layer (7), and a highly doped N-type gallium oxide region (8) arranged below the cathode, which are stacked in sequence from bottom to top;

[0011] The dielectric layer (4) covers the upper surface of the N-type gallium oxide epitaxial layer (3) to isolate the resistive field plate layer (5) from the N-type gallium oxide epitaxial layer (3) to ensure that current does not flow from the semiconductor to the anode through the resistive field plate layer (5); the resistive field plate layer (5) covers the upper surface of the dielectric layer (4), and its length is shorter than that of the dielectric layer (4) on both sides of the anode and cathode, forming a stepped structure; the anode metal extends and covers a portion of the upper surface of the dielectric layer (4) and the resistive field plate layer (5), forming a stepped field plate structure; the cathode metal extends and covers a portion of the upper surface of the dielectric layer (4) and the resistive field plate layer (5), forming a stepped field plate structure; and the two ends of the resistive field plate layer (5) are connected to the cathode and the anode, respectively.

[0012] Among them, the resistive field plate layer 5 has a very high and uniform resistivity; when the voltage-resistant area is reversely withstand voltage, a weak current flows through the resistive field plate. According to the principle of current continuity, a uniform potential distribution is generated on the current path, which can modulate the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed, so that the device can withstand a higher reverse breakdown voltage.

[0013] Furthermore, the resistivity of the resistive field plate layer (5) is 1 MΩ·cm~100 MΩ·cm.

[0014] Furthermore, the highly doped N-type gallium oxide region (8) is below the contact region between the cathode and the cathode stepped field plate layer (7) and the N-type gallium oxide epitaxial layer (3), and the remaining region of the N-type gallium oxide epitaxial layer (3) is low-doped.

[0015] In the above structure, the dielectric layer 4 is deposited above the N-type gallium oxide epitaxial layer 3; the resistive field plate layer 5 covers the upper surface of the dielectric layer 4, and its length is shorter than the dielectric layer 4 on both sides of the anode and the cathode, forming a stepped structure; in the anode and the anode stepped field plate layer 6, the stepped field plate is formed by extending the anode metal and partially covering the upper surface of the dielectric layer 4 and the resistive field plate layer 5 of different widths on the anode side; in the cathode and the cathode stepped field plate layer 7, the stepped field plate is formed by extending the cathode metal and partially covering the upper surface of the dielectric layer 4 and the resistive field plate layer 5 of different widths on the cathode side.

[0016] The material of the resistive field plate layer (5) is high-resistance nickel oxide, and its growth method can also adopt pulsed laser deposition, thermal oxidation and other methods other than magnetron sputtering.

[0017] Furthermore, the resistive field plate layer (5) has a thickness of 20-200 nm and a length of 10-20 μm.

[0018] The substrate (1) is an aluminum oxide heterogeneous substrate or an iron-doped gallium oxide homogeneous high-resistance substrate;

[0019] The thickness of the N-type gallium oxide epitaxial layer (3) is 200-1200 nm, and the N-type doping concentration is 10 16 ~5.0×10 17 cm -3 , the doping concentration of the highly doped N-type gallium oxide region (8) is 10 18 ~10 20 cm -3 ;

[0020] The dielectric layer (4) is made of aluminum oxide with a thickness of 20 to 100 nm;

[0021] The anode and the anode step field plate layer (6) are formed by evaporation deposition of Au, Ni, and Al. The total length of the anode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm.

[0022] The cathode and cathode step field plate layer (7) are deposited by evaporation of Ti, Ni, and Ag. The total length of the cathode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm.

[0023] Furthermore, the preparation method thereof comprises the following steps:

[0024] (1) Pre-treating the substrate to remove surface stains;

[0025] (2) epitaxially growing an unintentionally doped layer on the pretreated substrate;

[0026] (3) epitaxially growing an N-type gallium oxide epitaxial layer on the unintentionally doped layer;

[0027] (4) depositing a dielectric layer on the N-type gallium oxide epitaxial layer;

[0028] (5) Spin-coating photoresist on the surface of the dielectric layer and forming an opening pattern using a standard photolithography process;

[0029] (6) Etching the dielectric layer using a reactive ion etching process according to the opening pattern until the upper surface of the N-type gallium oxide epitaxial layer is reached;

[0030] (7) Spin-coating photoresist on the etched dielectric layer and forming a resistive field plate opening pattern using a standard photolithography process;

[0031] (8) growing the resistive field plate layer by magnetron sputtering according to the resistive field plate opening pattern;

[0032] (9) Performing a photolithography stripping process on the sample after magnetron sputtering to remove the photoresist;

[0033] (10) An ion implantation process is used to form a heavily doped region on the upper surface of the N-type gallium oxide epitaxial layer exposed on the cathode side;

[0034] (11) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer and forming an anode field plate opening pattern using a standard photolithography process;

[0035] (12) Depositing metal on the surface of the N-type gallium oxide epitaxial layer, the dielectric layer, and the resistive field plate layer by evaporation or sputtering according to the metal field plate opening pattern to form an anode metal with an anode step field plate structure;

[0036] (13) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer and forming a cathode field plate opening pattern using a standard photolithography process;

[0037] (14) According to the metal field plate opening pattern, metal is deposited on the surface of the N-type gallium oxide epitaxial layer, the dielectric layer and the resistive field plate layer by an evaporation or sputtering process to form a cathode metal with a cathode stepped field plate structure.

[0038] Furthermore, the pretreatment in step (1) includes immersing the substrate in an acetone solution, an isopropyl alcohol solution, and deionized water for ultrasonic cleaning for 5 to 15 minutes each, blowing the cleaned substrate dry with nitrogen, and then heat-treating the cleaned and dried substrate to remove surface contaminants;

[0039] In step (3), an N-type gallium oxide epitaxial layer is epitaxially grown on the unintentionally doped layer after epitaxial growth by using a hydride vapor phase epitaxy or metal organic compound chemical vapor deposition process.

[0040] Furthermore, in steps (12) and (14), the metal layer is deposited by using one or more sputtering processes including magnetron sputtering, thermal evaporation, and electron beam evaporation.

[0041] Furthermore, in steps (5), (7), (11), and (13), the specific method of spin coating is as follows: using a spin coater, first depositing at a speed of 200 to 800 rpm for a spin coating time of 8 to 12 s; then increasing the speed to 500 to 1500 rpm, spin coating for 30 to 90 s, and then annealing at a temperature of 50 to 150 °C for 30 to 90 s.

[0042] Compared with the existing technology, the design points of the present invention and its preferred embodiment include: First, the resistive field plate layer and the N-type gallium oxide epitaxial layer are isolated by a dielectric layer to ensure that the current does not flow from the semiconductor to the anode through the resistive field plate layer, so that the current on the resistive field plate is uniform and the electric field along the resistive field plate is also uniform. Second, the nickel oxide film is deposited by magnetron sputtering, and the experimental parameters such as sputtering power, sputtering argon-oxygen ratio, sputtering gas pressure and sputtering temperature in the magnetron sputtering are regulated to achieve a high-resistance nickel oxide film with uniform resistivity, thereby acting as a resistive field plate layer. Third, by adopting a resistive field plate layer, when the voltage-resistant area is reversely withstand voltage, a weak current flows through the resistive field plate, generating a uniform potential distribution on the current path, which can modulate the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed and improving the voltage withstand capability of the gallium oxide LSBD.

[0043] It proposes a new high-voltage gallium oxide lateral Schottky barrier diode realized by using resistive field plate technology. First, a dielectric layer is used to isolate the resistive field plate layer and the N-type gallium oxide epitaxial layer to ensure that the current does not flow from the semiconductor to the anode through the resistive field plate layer, so that the current on the resistive field plate is uniform and the electric field along the resistive field plate is also uniform. Secondly, magnetron sputtering deposition technology is used to realize a high-resistance nickel oxide film with uniform resistivity, which serves as the resistive field plate layer. Finally, the resistive field plate technology can be used to modulate the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed and optimizing the electric field peak, so as to achieve the purpose of obtaining a larger reverse breakdown voltage for the gallium oxide LSBD device. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] Figure 1This is a schematic structural diagram of a high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to an embodiment of the present invention;

[0046] Figure 2 This is a detailed process diagram for preparing a high-voltage gallium oxide lateral Schottky barrier diode using resistive field plate technology according to an embodiment of the present invention;

[0047] Figure 3 This is a diagram showing the relationship between the withstand voltage of a high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to an embodiment of the present invention and a conventional gallium oxide lateral Schottky barrier diode;

[0048] Figure 4 This is a comparison of the surface electric field distribution in the drift region when a high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology in an embodiment of the present invention is broken down with a gallium oxide lateral Schottky barrier diode of a conventional structure. DETAILED DESCRIPTION

[0049] To make the features and advantages of this patent more clearly understood, the following embodiments are specifically described in detail as follows:

[0050] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this application belongs.

[0051] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0052] like Figure 1As shown, an embodiment of the present invention provides a high-voltage gallium oxide lateral Schottky barrier diode realized by using resistive field plate technology, comprising a substrate 1, an unintentionally doped layer 2, an N-type gallium oxide epitaxial layer 3, a dielectric layer 4, a resistive field plate layer 5, an anode and an anode stepped field plate layer 6, a cathode and a cathode stepped field plate layer 7 stacked in sequence from bottom to top; further comprising a highly doped N-type gallium oxide region 8 disposed below the cathode; the dielectric layer 4 is deposited above the N-type gallium oxide epitaxial layer 3; the resistive field plate layer 5 covers the upper surface of the dielectric layer 4, and its length is shorter than the dielectric layer 4 on both sides of the anode and cathode, forming a stepped structure; in the anode and the anode stepped field plate layer 6, the stepped field plate extends from the anode metal and partially covers the anode metal. The dielectric layer 4 of different widths on the pole side is formed on the upper surface of the resistive field plate layer 5; in the cathode and cathode stepped field plate layer 7, the stepped field plate is extended by the cathode metal and partially covers the dielectric layer 4 of different widths on the cathode side and the upper surface of the resistive field plate layer 5; the highly doped N-type gallium oxide region 8 is below the contact area between the cathode and the cathode stepped field plate layer 7 and the N-type gallium oxide epitaxial layer 3, and the remaining area of ​​the N-type gallium oxide epitaxial layer 3 is low-doped; the resistive field plate layer 5 can adopt a high-resistance nickel oxide film with uniform resistivity, and the growth method can adopt magnetron sputtering, pulsed laser deposition, thermal oxidation and the like; the resistive field plate layer 5 can adopt a high-resistance nickel oxide film with uniform resistivity, and its resistivity needs to be controlled within 1 by regulating the growth conditions. MΩ·cm~100 MΩ·cm; the resistive field plate layer 5 can be made of a high-resistance nickel oxide film with uniform resistivity, and its thickness needs to be controlled by adjusting the growth conditions to be between 20 and 200 nm; the resistive field plate layer 5 can be made of a high-resistance nickel oxide film with uniform resistivity, and its length needs to be controlled by adjusting the growth conditions to be between 10 and 20 μm. The substrate 1 can be a high-resistance substrate doped with aluminum oxide or iron; the thickness of the N-type gallium oxide epitaxial layer 3 is 200~1200 nm, and the N-type doping concentration is 10 16 ~5.0×10 17 cm -3 , the doping concentration of the highly doped N-type gallium oxide region 8 is 10 18 ~10 20 cm -3 ; The dielectric layer 4 can be made of aluminum oxide with a thickness of 20~100 nm; the material of the anode and the anode step field plate layer 6 is selected from Au, Ni, and Al combined with evaporation deposition, the total length of the anode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm; the material of the cathode and the cathode step field plate layer 7 is selected from Ti, Ni, and Ag combined with evaporation deposition, the total length of the cathode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm.

[0053] Reference Figure 2 The present invention prepares a high-voltage gallium oxide lateral Schottky barrier diode using resistive field plate technology, and provides the following examples:

[0054] A high-voltage gallium oxide lateral Schottky barrier diode was prepared using resistive field plate technology, with a resistive field plate layer thickness of 200 nm, a resistive field plate layer length of 16 μm, a dielectric layer thickness of 100 nm, a total anode field plate length of 0.5 μm, anode step field plate width of 0.2 μm, a cathode field plate total length of 0.5 μm, and a cathode step field plate width of 0.2 μm.

[0055] (1) An iron-doped gallium oxide homogeneous high-resistance substrate 1 with a thickness of 500 μm was immersed in acetone solution, isopropyl alcohol solution and deionized water for ultrasonic cleaning in turn, and the cleaned iron-doped gallium oxide homogeneous high-resistance substrate 1 was blown dry with nitrogen. The cleaned and blown dry iron-doped gallium oxide homogeneous high-resistance substrate 1 was then heat-treated to remove surface contaminants.

[0056] (2) An unintentionally doped gallium oxide layer 2 with a thickness of 1.0 μm is epitaxially grown using the MOCVD process.

[0057] (3) The MOCVD process is used for epitaxial growth with a thickness of 0.2 μm and an N-type doping concentration of 1.2×10 17 cm -3 Gallium oxide epitaxial layer 3.

[0058] (4) epitaxially growing an aluminum oxide dielectric layer 4 with a thickness of 30 nm on the gallium oxide epitaxial layer 3, spin-coating a photoresist on the surface of the aluminum oxide dielectric layer 4, and forming an opening pattern using a standard photolithography process; etching the aluminum oxide dielectric layer 4 using a reactive ion etching process according to the opening pattern until the upper surface of the N-type gallium oxide epitaxial layer 3 is reached;

[0059] (5) A resistive field plate opening pattern was formed on the etched aluminum oxide dielectric layer 4 using a standard photolithography process. Experimental parameters such as RF power, RF temperature, RF argon-oxygen ratio, and RF pressure were controlled by magnetron sputtering deposition technology to achieve a high-resistance nickel oxide thin film layer with a thickness of 200 nm, a resistivity of 100 MΩ·cm, and a length of 16 μm, which served as the resistive field plate layer 5. The sample after magnetron sputtering was immersed in acetone solution, isopropyl alcohol solution, and deionized water in turn to perform a photolithography stripping process to remove the photoresist.

[0060] (6) The surface of the N-type gallium oxide epitaxial layer 3 exposed on the cathode side is subjected to an ion implantation process to form an N-type doping concentration of 10 20 cm -3 Heavily doped region 8.

[0061] (7) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer 3, and forming an anode field plate opening pattern by a standard photolithography process; according to the metal field plate opening pattern, depositing metal on the surface of the N-type gallium oxide epitaxial layer 3, the dielectric layer 4 and the resistive field plate layer 5 by an evaporation or sputtering process to form an anode metal with an anode stepped field plate structure.

[0062] (8) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer 3, and forming a cathode field plate opening pattern by a standard photolithography process; according to the metal field plate opening pattern, depositing metal on the surface of the N-type gallium oxide epitaxial layer 3, the dielectric layer 4 and the resistive field plate layer 5 by an evaporation or sputtering process to form a cathode metal with a cathode stepped field plate structure.

[0063] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

[0064] The working principle of the present invention is as follows: first, a dielectric layer is grown on the surface of the gallium oxide epitaxial layer to isolate the resistive field plate layer and the N-type gallium oxide epitaxial layer, ensuring that the current does not flow from the semiconductor through the resistive field plate layer to the anode, so that the current on the resistive field plate is uniform and the electric field along the resistive field plate is also uniform. Secondly, a high-resistance nickel oxide film with uniform resistivity is achieved through magnetron sputtering deposition technology, which serves as the resistive field plate layer. Finally, with the help of the resistive field plate technology, when the withstand voltage area is reversely withstand voltage, a weak current flows through the resistive field plate. According to the principle of current continuity, a uniform potential distribution is generated on the current path, which can modulate the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed and withstanding a higher reverse breakdown voltage, thereby obtaining a gallium oxide LSBD device with excellent performance.

[0065] Figure 3 The comparison of the withstand voltage relationship between the high withstand voltage gallium oxide lateral Schottky barrier diode realized by resistive field plate technology in the embodiment of the present invention and the conventional gallium oxide lateral Schottky barrier diode is given. Figure 3 It can be seen that the breakdown voltage of the conventional gallium oxide lateral Schottky barrier diode without the resistive field plate technology is only 1462 V, while the breakdown voltage of the high-voltage gallium oxide lateral Schottky barrier diode achieved by the resistive field plate technology reaches 2057 V, and the device breakdown voltage is increased by 41%.

[0066] Figure 4A comparison of the surface electric field distribution of the drift region when a high-voltage gallium oxide lateral Schottky barrier diode implemented with resistive field plate technology in an embodiment of the present invention is shown with a conventional gallium oxide lateral Schottky barrier diode. Figure 4 It can be seen that the drift region surface of the conventional gallium oxide lateral Schottky barrier diode without the use of resistive field plate technology is mainly composed of Schottky junction and N + The electric field is borne near the N-junction, and the high-voltage gallium oxide lateral Schottky barrier diode realized by resistive field plate technology has more areas on the drift region surface to share the electric field, making the electric field distribution more uniform, greatly improving the voltage resistance of the gallium oxide lateral Schottky barrier diode.

[0067] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

[0069] This patent is not limited to the above-mentioned optimal implementation method. Anyone can derive various other forms of high-voltage gallium oxide lateral Schottky barrier diodes using resistive field plate technology based on the inspiration of this patent. All equivalent changes and modifications made within the scope of the patent application of this invention should be covered by this patent.

Claims

1. A high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology, characterized in that: The resistive field plate layer and the N-type gallium oxide epitaxial layer are isolated by a dielectric layer to ensure that the current does not flow from the semiconductor to the anode through the resistive field plate layer, so that the current on the resistive field plate is uniform; Due to the high resistivity of the resistive field plate layer, when the withstand voltage region is reversely withstand voltage, a weak current flows through the resistive field plate, generating a uniform potential distribution along the current path, thereby modulating the surface electric field distribution in the semiconductor, making the surface electric field uniformly distributed, thereby increasing the reverse breakdown voltage; The invention comprises a substrate (1), an unintentionally doped layer (2), an N-type gallium oxide epitaxial layer (3), a dielectric layer (4), a resistive field plate layer (5), an anode and an anode stepped field plate layer (6), a cathode and a cathode stepped field plate layer (7), and a highly doped N-type gallium oxide region (8) arranged below the cathode. The dielectric layer (4) covers the upper surface of the N-type gallium oxide epitaxial layer (3) to isolate the resistive field plate layer (5) from the N-type gallium oxide epitaxial layer (3) to ensure that current does not flow from the semiconductor to the anode through the resistive field plate layer (5); the resistive field plate layer (5) covers the upper surface of the dielectric layer (4) and is shorter than the dielectric layer (4) on both sides of the anode and cathode, forming a stepped structure; the anode metal extends and covers a portion of the upper surface of the dielectric layer (4) and the resistive field plate layer (5), forming a stepped field plate structure; The cathode metal extends and covers a portion of the dielectric layer (4) and the upper surface of the resistive field plate layer (5), forming a stepped field plate structure; the two ends of the resistive field plate layer (5) are respectively connected to the cathode and the anode; The highly doped N-type gallium oxide region (8) is below the contact region between the cathode and the cathode stepped field plate layer (7) and the N-type gallium oxide epitaxial layer (3), and the remaining region of the N-type gallium oxide epitaxial layer (3) is low-doped; The resistive field plate layer (5) has a thickness of 20-200 nm and a length of 10-20 μm; The substrate (1) is an aluminum oxide heterogeneous substrate or an iron-doped gallium oxide homogeneous high-resistance substrate; The thickness of the N-type gallium oxide epitaxial layer (3) is 200-1200 nm, and the N-type doping concentration is 10 16 ~5.0×10 17 cm -3 , the doping concentration of the highly doped N-type gallium oxide region (8) is 10 18 ~10 20 cm -3 ; The dielectric layer (4) is made of aluminum oxide with a thickness of 20 to 100 nm; The anode and the anode step field plate layer (6) are formed by evaporation deposition of Au, Ni, and Al. The total length of the anode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm. The cathode and cathode step field plate layer (7) are deposited by evaporation of Ti, Ni, and Ag. The total length of the cathode step field plate is 0.2-5.0 μm, and the step width is 0.2-5.0 μm.

2. The high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to claim 1, characterized in that: The resistive field plate layer is prepared by depositing a nickel oxide film by magnetron sputtering technology, and regulating the parameters of the magnetron sputtering, including radio frequency power, radio frequency temperature, radio frequency argon-oxygen ratio, and radio frequency pressure, to achieve a high-resistance nickel oxide film with uniform resistivity.

3. The high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to claim 1, characterized in that: The resistivity of the resistive field plate layer (5) is 1 MΩ·cm to 100 MΩ·cm.

4. The high-voltage gallium oxide lateral Schottky barrier diode realized by using resistive field plate technology according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Pre-treating the substrate to remove surface stains; (2) epitaxially growing an unintentionally doped layer on the pretreated substrate; (3) epitaxially growing an N-type gallium oxide epitaxial layer on the unintentionally doped layer; (4) depositing a dielectric layer on the N-type gallium oxide epitaxial layer; (5) Spin-coating photoresist on the surface of the dielectric layer and forming an opening pattern using a standard photolithography process; (6) Etching the dielectric layer using a reactive ion etching process according to the opening pattern until the upper surface of the N-type gallium oxide epitaxial layer is reached; (7) Spin-coating photoresist on the etched dielectric layer and forming a resistive field plate opening pattern using a standard photolithography process; (8) growing the resistive field plate layer by magnetron sputtering according to the resistive field plate opening pattern; (9) Performing a photolithography stripping process on the sample after magnetron sputtering to remove the photoresist; (10) An ion implantation process is used to form a heavily doped region on the upper surface of the N-type gallium oxide epitaxial layer exposed on the cathode side; (11) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer and forming an anode field plate opening pattern using a standard photolithography process; (12) Depositing metal on the surface of the N-type gallium oxide epitaxial layer, the dielectric layer, and the resistive field plate layer by evaporation or sputtering according to the metal field plate opening pattern to form an anode metal with an anode step field plate structure; (13) Spin-coating photoresist on the surface of the N-type gallium oxide epitaxial layer and forming a cathode field plate opening pattern using a standard photolithography process; (14) According to the metal field plate opening pattern, metal is deposited on the surface of the N-type gallium oxide epitaxial layer, the dielectric layer and the resistive field plate layer by an evaporation or sputtering process to form a cathode metal with a cathode stepped field plate structure.

5. The high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to claim 4, characterized in that: The pretreatment in step (1) includes immersing the substrate in an acetone solution, an isopropyl alcohol solution, and deionized water for ultrasonic cleaning for 5 to 15 minutes each, blowing the cleaned substrate dry with nitrogen, and then heat-treating the cleaned and dried substrate to remove surface contaminants; In step (3), an N-type gallium oxide epitaxial layer is epitaxially grown on the unintentionally doped layer after epitaxial growth by using a hydride vapor phase epitaxy or metal organic compound chemical vapor deposition process.

6. The high-voltage gallium oxide lateral Schottky barrier diode implemented using resistive field plate technology according to claim 4, characterized in that: In steps (12) and (14), the metal layer is deposited by one or more sputtering processes including magnetron sputtering, thermal evaporation, and electron beam evaporation.

7. The high-voltage gallium oxide lateral Schottky barrier diode realized by using resistive field plate technology according to claim 4, characterized in that: In steps (5), (7), (11), and (13), the specific method of spin coating is as follows: using a spin coater, first deposit at a speed of 200 to 800 rpm for a spin coating time of 8 to 12 s; then increase the speed to 500 to 1500 rpm, spin coat for 30 to 90 s, and then anneal at a temperature of 50 to 150 °C for 30 to 90 s.

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