Gallium oxide power diode with anti-single particle irradiation and preparation method thereof

Abstract

This invention relates to the field of semiconductor device technology, specifically to a gallium oxide power diode resistant to single-particle irradiation and its fabrication method. The gallium oxide power diode includes a cathode, a gallium oxide substrate, a gallium oxide epitaxial layer, a nickel oxide layer, a dielectric layer, and an anode, arranged sequentially. Multiple trenches are formed on the upper surface of the gallium oxide epitaxial layer. The nickel oxide layer covers the bottom and sidewalls of each trench. The nickel oxide layer includes a first nickel oxide layer and a second nickel oxide layer. The dielectric layer is disposed on the upper surface of the second nickel oxide layer and surrounds the outside of the second nickel oxide layer, forming multiple first trenches. The dielectric layer has multiple second trenches. The anode is disposed on the upper surface of the dielectric layer and fills both the first and second trenches. This gallium oxide power diode utilizes a junction termination extension structure to transfer the single-particle irradiation sensitive location from the anode edge to the junction region. Simultaneously, a trench structure is used in the junction region to effectively extract irradiation-induced holes, improving the single-particle burn-off voltage of the device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, specifically to a gallium oxide power diode resistant to single-particle irradiation and its fabrication method. Background Technology

[0002] β-Ga₂O₃ exhibits great potential in the field of radiation-hardened electronic devices due to its ultrawide bandgap, high shift threshold energy, and high electron-hole pair generation energy. In complex radiation environments, the stability of electronic devices is crucial for ensuring the normal operation of equipment such as nuclear power supplies and spacecraft. Among various radiation effects, single-event effects often lead to transient, permanent, and catastrophic failures of devices. Therefore, enhancing the single-event irradiation hardness of β-Ga₂O₃ power devices is essential for promoting their gradual replacement of Si-based power semiconductor devices in the aerospace field.

[0003] Current research indicates that NiO / β-Ga2O3 heterojunction diodes outperform similar Schottky diodes in reverse breakdown voltage. Furthermore, bipolar devices exhibit stronger single-particle irradiation hardness for Si and SiC-based power devices, a finding that has been preliminarily verified in β-Ga2O3 power diodes. In April 2024, Professor Long Shibing's team enhanced the p-type region's ability to withstand irradiation-induced charges by increasing the NiO thickness, reducing the surface electric field of the epitaxial layer under single-particle irradiation and raising the single-particle burn-off voltage from 220V to approximately 270V. However, the electric field accumulation effect at the anode edge under heavy-ion irradiation further deteriorates, easily leading to premature device burn-off. Simultaneously, the surface electric field of the epitaxial layer in the junction region of the power diode is not effectively controlled, making it prone to thermal runaway due to surface hole accumulation under single-particle irradiation. Summary of the Invention

[0004] To address the technical problem that existing power diodes are prone to single-particle burn-out at the anode edge due to the electric field concentration effect under heavy ion irradiation, leading to permanent failure of the power diode, this invention provides a gallium oxide power diode resistant to single-particle irradiation and its fabrication method.

[0005] This invention employs the following technical solution: a gallium oxide power diode resistant to single-particle irradiation, comprising: a gallium oxide wafer, a nickel oxide layer, a dielectric layer, a cathode, and an anode. The gallium oxide wafer includes, from bottom to top, a gallium oxide substrate layer and a gallium oxide epitaxial layer, with multiple trenches on the upper surface of the gallium oxide epitaxial layer. The nickel oxide layer is disposed on the upper surface of the gallium oxide epitaxial layer and covers the bottom surface and sidewalls of each trench. The nickel oxide layer has multiple spaced protrusions along its length, with spacing between its ends and the sidewalls of the gallium oxide wafer. The nickel oxide layer includes, from bottom to top, a first nickel oxide layer and a second nickel oxide layer, where the concentration of the first nickel oxide layer is lower than that of the second nickel oxide layer, but its thickness is greater. The dielectric layer is disposed on the upper surface of the second nickel oxide layer and surrounds the outside of the second nickel oxide layer, forming a groove (the same number as the trenches). The dielectric layer is aligned with the two sidewalls of the gallium oxide wafer on both sides, and groove 2 is provided on the upper surface of the protruding portion of the nickel oxide layer 2. Groove 2 is used to divide the dielectric layer into a multi-segment structure along its length. The cathode is disposed on the lower surface of the gallium oxide substrate. The anode is disposed on the upper surface of the dielectric layer and fills groove 1 and groove 2 respectively; the two ends of the anode extend outward along groove 2 to partially stack on the upper surface of the outermost dielectric layer. As a further improvement of the present invention, groove one and groove two are staggered along the length direction of the nickel oxide layer, and groove two is symmetrically arranged on the upper surface of nickel oxide layer two with the central axis of the protrusion formed by nickel oxide layer two as the axis of symmetry.

[0006] As a further improvement of the present invention, the second groove divides the dielectric layer into multiple dielectric layers one and two symmetrically arranged dielectric layers two; each dielectric layer one is arranged in a U-shape and both ends of the U-shaped opening extend outward; the two dielectric layers two are symmetrically arranged on both sides of the dielectric layer one, and the outer side of the dielectric layer two is aligned with the outer side of the gallium oxide wafer and arranged in a multi-level stepped manner.

[0007] As a further improvement of the present invention, the depth of the trench ranges from 400nm to 1200nm.

[0008] As a further improvement of the present invention, the thickness of the first nickel oxide layer is in the range of 100nm-300nm, and the thickness of the second nickel oxide layer is in the range of 50nm-100nm.

[0009] As a further improvement of the present invention, the concentration range of the first nickel oxide layer is 0.5 × 10⁻⁶. 19 cm -3 ~1.0×10 19 cm -3 The concentration range of the second nickel oxide layer is 2.0 × 10⁻⁶. 19 cm -3 ~5.0×10 19 cm -3 .

[0010] As a further improvement of the present invention, the dielectric layer is a barium titanate layer.

[0011] As a further improvement of the present invention, nickel oxide layer one and nickel oxide layer two are used to form a double-layer JTE junction termination extension structure between the nickel oxide epitaxial layer and the gallium oxide epitaxial layer; the double-layer JTE junction termination extension structure is used to transfer the irradiation sensitive position in the gallium oxide power diode under single-particle irradiation from the anode edge to the junction region.

[0012] As a further improvement of the present invention, the anode is made of Ni / Au alloy.

[0013] As a further improvement of the present invention, the cathode is made of a Ti / Au alloy.

[0014] This invention also includes a method for fabricating a gallium oxide power diode with single-particle irradiation resistance as described above, comprising: providing a gallium oxide wafer; growing cathode metal on the back side of the gallium oxide wafer to form a cathode; forming multiple trenches by dry etching on the upper surface of the gallium oxide wafer using nickel metal as a mask; removing the mask metal with a piranha solution and immersing in hot phosphoric acid at 120°C for 3 minutes; depositing a nickel oxide layer 1 and a nickel oxide layer 2 on the gallium oxide wafer using magnetron sputtering, wherein the thickness ratio of the deposited nickel oxide layer 1 to nickel oxide layer 2 is 3:1; depositing a dielectric layer on the nickel oxide layer 2 using magnetron sputtering; and finally depositing an anode metal on the upper surface of the dielectric layer using magnetron sputtering, filling trenches 1 and 2, thereby forming a gallium oxide power diode with single-particle irradiation resistance.

[0015] As a further improvement of the present invention, the gallium oxide wafer is formed by depositing a lightly doped gallium oxide epitaxial layer on the upper surface of a highly doped gallium oxide substrate.

[0016] The technical solution provided by this invention has the following beneficial effects: (1) The gallium oxide power diode with single-particle irradiation resistance provided by the present invention utilizes the JTE junction termination extension structure to transfer the single-particle irradiation sensitive position from the anode edge to the junction region, and at the same time adopts a trench structure in the junction region to effectively extract irradiation-induced holes, thereby improving the single-particle burn-off voltage of the gallium oxide power diode.

[0017] (2) The gallium oxide power diode with single-particle irradiation resistance provided by the present invention constructs a double-layer JTE junction termination extension structure by using a low-concentration and thick nickel oxide layer 1 and a high-concentration and thin nickel oxide layer 2. The nickel oxide layer 1 increases the ability to bear irradiation-induced charges, and the nickel oxide layer 2 suppresses hole accumulation on the surface of the nickel oxide layer. The two work together to transfer the single-particle irradiation sensitive position from the anode edge to the junction region. Furthermore, by constructing a trench structure in the junction region, the constructed trench structure can effectively extract holes under single-particle irradiation, thereby reducing the electric field strength and heat dissipation of the junction region, thereby improving the radiation resistance of the gallium oxide power diode and ultimately increasing its single-particle burn-out voltage.

[0018] (3) The gallium oxide power diode with single-particle irradiation resistance provided by the present invention can not only effectively protect the bottom of the trench by setting a dielectric layer, but also form a MOS structure with the gallium oxide epitaxial layer, thereby using polarization charge to bear the electric field of the junction region in the gallium oxide epitaxial layer, further enhancing the radiation resistance capability of the gallium oxide power diode. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a gallium oxide power diode with resistance to single-particle irradiation provided by the present invention.

[0020] Figure 2 The flowchart illustrates the steps of the method for fabricating a gallium oxide power diode resistant to single-particle irradiation provided by the present invention.

[0021] Figure 3 Figure 1 shows the forward and reverse current-voltage characteristic curves of the gallium oxide power diode of the present invention; wherein Figure 2a is the forward current-voltage characteristic curve of the gallium oxide power diode, and Figure 3b is the reverse current-voltage characteristic curve of the gallium oxide power diode.

[0022] Figure 4 The diagrams show the hole current density and temperature distribution of the junction region and JTE junction termination extension structure of the gallium oxide power diode in this scheme when irradiated with heavy ions, respectively. Figure a shows the hole current density distribution of the junction region of the gallium oxide power diode when irradiated with heavy ions; Figure b shows the hole current density distribution of the JTE junction termination extension structure of the gallium oxide power diode when irradiated with heavy ions; Figure c shows the temperature distribution of the junction region of the gallium oxide power diode when irradiated with heavy ions; and Figure d shows the temperature distribution of the junction region of the gallium oxide power diode when irradiated with heavy ions.

[0023] Figure 5The diagrams show the space charge density distribution and electric field distribution of the gallium oxide power diodes in the control group and the present scheme, respectively, when irradiated with single particles. Figure a shows the space charge density distribution of the gallium oxide power diode in the control group at a single layer of nickel oxide; Figure b shows the space charge density distribution of the gallium oxide power diode in the present scheme at a single layer of nickel oxide; Figure c shows the electric field distribution of the gallium oxide power diode in the control group at a single layer of nickel oxide; and Figure d shows the electric field distribution of the gallium oxide power diode in the present scheme at a double layer of nickel oxide.

[0024] Figure 6 The figures show schematic diagrams of the hole current density distribution and electric field distribution obtained when the gallium oxide power diodes of control group 2 and this scheme are irradiated by single particles, respectively. Figure a shows the hole current density distribution of the gallium oxide power diode of control group 2 at the heterojunction interface; Figure b shows the hole current density distribution of the gallium oxide power diode of this scheme at the heterojunction interface; Figure c shows the electric field distribution of the gallium oxide power diode of control group 2 at the heterojunction interface; and Figure d shows the electric field distribution of the gallium oxide power diode of this scheme at the heterojunction interface.

[0025] Figure 7 The diagrams show the space charge density distribution and electric field distribution of the gallium oxide power diodes in control group 3 and this scheme, respectively, obtained by single-particle irradiation. Figure a shows the space charge density distribution of the gallium oxide power diode in control group 3 at the heterojunction interface; Figure b shows the space charge density distribution of the gallium oxide power diode in this scheme at the heterojunction interface; Figure c shows the electric field distribution of the gallium oxide power diode in control group 3 at the heterojunction interface; and Figure d shows the electric field distribution of the gallium oxide power diode in this scheme at the heterojunction interface.

[0026] Figure 8 This is a schematic diagram of the gallium oxide power diode in control group four.

[0027] Figure 9 The diagrams show a comparison of the reverse leakage current of the gallium oxide power diode in control group 4 and the present scheme over time; Figure a shows the curve of the reverse leakage current of the gallium oxide power diode in control group 4 over time; Figure b shows the curve of the reverse leakage current of the gallium oxide power diode in the present scheme over time.

[0028] The markings in the figure are as follows: 1. Gallium oxide substrate; 2. Gallium oxide epitaxial layer; 21. Trench; 3. Nickel oxide layer; 4. Dielectric layer; 41. Trench 1; 42. Trench 2; 5. Cathode; 6. Anode. Detailed Implementation

[0029] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0030] In the description of this invention, it should be noted that directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific scope of protection of this invention. The terms "first," "second," etc., in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0031] This embodiment provides a gallium oxide power diode resistant to single-particle irradiation. Please refer to [reference needed]. Figure 1 and Figure 2The diode comprises, from bottom to top, a cathode 5, a gallium oxide wafer, a nickel oxide layer 3, a dielectric layer 4, and an anode 6. The gallium oxide wafer includes a gallium oxide substrate 1 and a gallium oxide epitaxial layer 2. The gallium oxide epitaxial layer 2 is disposed on the upper surface of the gallium oxide substrate 1, and multiple trenches 21 are formed on the upper surface of the gallium oxide epitaxial layer 2. The purpose of forming multiple trenches 21 is to enable the effective extraction of holes under the single-event effect, reducing the local electric field strength and heat dissipation, thereby improving the electric field distribution of the fabricated gallium oxide power diode, reducing leakage current, and increasing breakdown voltage. The cathode 5 is disposed on the lower surface of the gallium oxide substrate 1, and an ohmic contact can be formed between the cathode 5 and the gallium oxide substrate 1. The nickel oxide layer 3 is disposed on the upper surface of the gallium oxide epitaxial layer 2 and covers the bottom surface and sidewalls of each trench 21. A JTE junction termination extension structure can be formed between the nickel oxide layer 3 and the gallium oxide epitaxial layer 2. The nickel oxide layer 3 has multiple spaced protrusions along its length, and there are gaps between both ends of the nickel oxide layer 3 and the sidewalls of the gallium oxide epitaxial layer 2. The nickel oxide layer 3 includes a first nickel oxide layer and a second nickel oxide layer. The first nickel oxide layer is disposed on the upper surface of the gallium oxide epitaxial layer 2, and the second nickel oxide layer is disposed on the upper surface of the first nickel oxide layer. This solution, by setting a double-layer nickel oxide layer 3 on the upper surface of the gallium oxide epitaxial layer 2, can form a double-layer JTE junction termination extension structure. This double-layer JTE junction termination extension structure can effectively transfer the irradiation-sensitive position of the gallium oxide power diode under single-particle irradiation from the edge of the anode 6 to the junction region, avoiding localized damage, breakdown, or corrosion at the edge of the anode 6 due to electric field concentration, thereby improving the overall stability of the gallium oxide power diode. Furthermore, after transferring the irradiation-sensitive position to the junction region, the current can be more evenly distributed through the space charge of the junction region, enabling the gallium oxide power diode to withstand higher reverse voltages and improving its withstand voltage performance. The concentration of nickel oxide layer one is lower than that of nickel oxide layer two, and the thickness of nickel oxide layer one is greater than that of nickel oxide layer two. By employing a double-layer nickel oxide layer 3, the thicker and lower-concentration nickel oxide layer one allows irradiation-induced non-equilibrium carriers to be extracted into the nickel oxide under the influence of an electric field, leading to electric field accumulation in the nickel oxide. The thicker nickel oxide layer one can improve its ability to bear irradiation charge, accommodating more non-equilibrium carriers, thereby reducing the local electric field and ensuring a lower heterojunction interface electric field. Meanwhile, the high-concentration nickel oxide layer two can expand the distribution of irradiation charge in the p-type region, suppressing electric field accumulation in the nickel oxide and improving the uniformity of the electric field distribution in the pn heterojunction formed between nickel oxide layer 3 and gallium oxide layer. Furthermore, this scheme also employs a trench 21 structure in the junction region. The trench 21 structure can effectively extract irradiation charge, effectively suppressing the accumulation of local electric field at the pn junction and reducing the irradiation damage interface of the gallium oxide power diode.In summary, this scheme utilizes a junction termination extension structure to transfer the single-particle irradiation sensitive location from the edge of the anode 6 to the junction region. At the same time, a trench 21 structure is used in the junction region to effectively extract irradiation-induced holes. The synergistic effect of these two methods can effectively improve the single-particle burn-off voltage of the gallium oxide power diode.

[0032] A dielectric layer 4 is disposed on the upper surface of the nickel oxide layer 3 and surrounds the outer side of the nickel oxide layer 2, thereby forming grooves 41 in the same number as trenches 21. The two sides of the dielectric layer 4 are aligned with the sidewalls of the gallium oxide epitaxial layer 2, and grooves 42 are provided on the upper surface of the protruding portion of the nickel oxide layer 4. Grooves 42 divide the dielectric layer 4 into multi-segment structures along its length. The dielectric layer 4 forms a MOS capacitor with the semiconductor material, and its polarization charge can compensate for radiation-induced charges and suppress the electric field accumulation effect in the semiconductor material. An anode 6 is disposed on the upper surface of the dielectric layer 4 and fills both grooves 41 and 42. The two ends of the anode 6 extend outward along groove 42 to partially stack on the upper surface of the outermost dielectric layer 4. A Schottky contact can be formed at the interface between the anode 6 and the nickel oxide layer 3, generating a space charge region on one side of the nickel oxide layer. A MOS structure can be formed between the dielectric layer 4 and the gallium oxide epitaxial layer 2. The formed MOS structure can utilize polarization charges to bear the local electric field in the gallium oxide epitaxial layer 2, that is, to transfer the local electric field from the interface between the nickel oxide layer 3 and the gallium oxide epitaxial layer 2 to the dielectric layer 4, further enhancing the radiation resistance of the gallium oxide power diode. In this scheme, the dielectric layer 4 is included outside the nickel oxide layer 2, and the dielectric layer 4 can form the same number of grooves 41 as the trenches 21, that is, the dielectric layer 4 covers the bottom surface and sidewalls of each trench 21, thereby protecting the structure of the trench 21.

[0033] The dielectric layer 4 can be made of barium titanate with a high dielectric constant. The advantages of using barium titanate with a high dielectric constant as the dielectric layer 4 are as follows: Barium titanate (BaTiO3) with a high dielectric constant has excellent electric field modulation ability, which can effectively disperse the electric field concentration on the surface of gallium oxide diode, expand the depletion region, suppress edge breakdown and leakage current, significantly improve the breakdown voltage, high temperature stability and reliability of gallium oxide power diode, and at the same time facilitate device miniaturization.

[0034] In this configuration, groove 1 41 and groove 2 42 are staggered along the length of nickel oxide layer 3, and groove 2 42 is symmetrically arranged on the upper surface of nickel oxide layer 2 with the central axis of the protrusion formed by nickel oxide layer 2 as the axis of symmetry. Groove 2 42 is connected to the anode metal to achieve good forward conduction of the device, while the trench 21 structure effectively suppresses the electric field accumulation effect on the surface of the epitaxial layer inside groove 2 42.

[0035] The second groove 42 divides the dielectric layer 4 into multiple dielectric layers 1 with the same structure and two dielectric layers 2 arranged symmetrically. Each dielectric layer 1 is U-shaped with both ends of the U-shaped opening extending outwards. The two dielectric layers 2 are symmetrically arranged on both sides of the dielectric layer 1, and the outer side of the dielectric layer 2 is aligned with the outer side of the gallium oxide epitaxial layer 2, forming a multi-level stepped arrangement. The middle dielectric layer 1 can diffuse the strong electric field in the region of the groove 41 below the anode 6 into the gallium oxide epitaxial layer 2, significantly reducing the central peak electric field. At the same time, it can also disrupt the continuous leakage current channel and suppress the formation of conductive filaments. The multi-level stepped dielectric layers 2 on both sides can smooth the electric field at the edge of the anode 6 and suppress the edge breakdown of the anode 6. The synergistic effect of the two makes the entire surface of the gallium oxide power diode form a uniform electric field distribution. This not only improves the electric field modulation efficiency through the high-k characteristic, but also further suppresses electric field accumulation and leakage current through the composite structure of dielectric layer 1 and dielectric layer 2. At the same time, it disperses local hot spots to improve high-temperature stability, thereby significantly improving the breakdown voltage, high-temperature stability and other advantages of the gallium oxide power diode.

[0036] In this design, the depth of trench 21 can be 800 nm, the thickness of nickel oxide layer one can be 300 nm, and the thickness of nickel oxide layer two can be 100 nm. The concentration of nickel oxide layer one can be 5 × 10⁻⁶. 18 cm -3 The concentration of the second nickel oxide layer can be 2.0 × 10⁻⁶. 19 cm -3 .

[0037] The anode 6 can be made of Ni / Au alloy, and the cathode 5 can be made of Ti / Au alloy.

[0038] Based on the gallium oxide power diode with the specific structure described above, this embodiment also provides a method for fabricating a gallium oxide power diode. Please refer to [link / reference]. Figure 2 It includes the following steps: (i) A gallium monoxide wafer is provided, comprising a gallium oxide substrate layer 1 and a gallium oxide epitaxial layer 2. The gallium oxide wafer can be formed by depositing a lightly doped gallium oxide epitaxial layer 2 on the upper surface of a highly doped gallium oxide substrate layer 1. The prepared gallium oxide wafer is ultrasonically cleaned using organic solvents such as acetone and isopropanol, and then acid-washed using piranha solution (SPM) and buffer oxide etchant (BOE solution).

[0039] (ii) A cathode 5 metal is deposited on the lower surface of the gallium oxide substrate 1 by electron beam evaporation and then rapidly annealed at 470°C for 1 minute to form the cathode 5; the cathode 5 forms an ohmic contact with the gallium oxide substrate 1. The purpose of rapid annealing at 470°C for 1 minute is to improve the quality of the ohmic contact.

[0040] (III) Multiple trenches 21 are formed by dry etching on the upper surface of the gallium oxide epitaxial layer 2 using nickel metal as a mask. The nickel mask is then removed with a piranha solution, and the surface is immersed in hot phosphoric acid at 120°C for 3 minutes. The process gas used for dry etching is BCl3 / Ar, with a flow rate of 35 / 5 sccm, a pressure of 5 mtorr, and an etching time of 10 min. Under this process, trenches 21 with a depth of approximately 800 nm can be obtained. The purpose of immersing the surface in hot phosphoric acid at 120°C for 3 minutes is to repair etching damage.

[0041] (iv) A nickel oxide layer 1 and a nickel oxide layer 2 are deposited on a gallium oxide wafer using magnetron sputtering. The thickness of the nickel oxide layer 1 is 300 nm, and the thickness of the nickel oxide layer 2 is 100 nm. The argon-oxygen ratio in the gas atmosphere can be 36:1.88 sccm when the nickel oxide layer 1 is generated by magnetron sputtering, and the argon-oxygen ratio in the gas atmosphere can be 19.5:29 sccm when the nickel oxide layer 2 is generated by magnetron sputtering.

[0042] (v) Then, a dielectric layer 4 is deposited on the upper surface of the nickel oxide layer 2 by magnetron sputtering at 150W and in a gas atmosphere with an argon-oxygen ratio of 35:5sccm; the thickness of the deposited dielectric layer 4 can be 100nm.

[0043] (vi) Finally, anode 6 metal is deposited on the upper surface of dielectric layer 4 using magnetron sputtering process, and grooves 41 and 42 are filled to form a gallium oxide power diode resistant to single-particle irradiation.

[0044] In step (vi), the deposited anode 6 metal is 40 / 80nm Ni / Au. The patterning of the nickel oxide layer 3, the dielectric layer 4, and the anode 6 all adopt a stripping process. Since this fabrication process is commonly used in the existing technology for gallium oxide power diodes, this solution will not describe it in detail.

[0045] Performance testing To verify the performance of the gallium oxide power diode with single-particle irradiation resistance provided by this scheme, a gallium oxide power diode was fabricated according to the above experimental steps, and the following experiments were conducted.

[0046] (I) Forward and reverse characteristics The forward and reverse voltages of the anode 6 of the gallium oxide power diode were scanned point by point using a semiconductor parameter analyzer, and the corresponding currents were measured simultaneously. This yielded the forward and reverse current-voltage characteristic curves of the gallium oxide power diode, as shown below. Figure 3 As shown. By analyzing... Figure 3 Analysis shows that the gallium oxide power diode provided in this solution has good forward conduction characteristics and its breakdown voltage is around 1800V.

[0047] (II) Study on sensitive locations of heavy ion irradiation When heavy ion irradiation was applied to the junction region of a gallium oxide power diode and the JTE junction termination extension structure, the hole current density and temperature distribution of the junction region of the gallium oxide power diode, and the hole current density and temperature distribution of the gallium oxide power diode at the JTE junction termination extension structure, were obtained respectively. Figure 4 .in, Figure 4 a is a schematic diagram of the hole current density distribution in the junction region of a gallium oxide power diode under heavy ion irradiation; Figure 4 b is a schematic diagram of the hole current density distribution when the JTE junction of a gallium oxide power diode is terminated with heavy ion irradiation. Figure 4 c is a schematic diagram of the temperature distribution in the junction region of a gallium oxide power diode under heavy ion irradiation; Figure 4 Figure d shows the temperature distribution of the JTE junction termination extension structure of a gallium oxide power diode under heavy ion irradiation. Through analysis of... Figure 4 Analysis of the four figures shows that the sensitive location of the gallium oxide power diode in this scheme under heavy ion irradiation is in the junction region. This proves that this scheme utilizes the JTE junction termination extension structure to transfer the single-particle irradiation sensitive location from the edge of anode 6 to the junction region.

[0048] (III) The Influence of Single-Layer Nickel Oxide and Double-Layer Nickel Oxide on the Charge Density and Electric Field Distribution of Gallium Oxide Power Diodes A set of gallium oxide power diodes with a single-layer nickel oxide layer were constructed as described above to serve as a control group to study the impact of single-layer and double-layer nickel oxide on the performance of gallium oxide power diodes. The gallium oxide power diodes in control group one were manufactured in the same manner as in this scheme, except that control group one used a low-concentration nickel oxide layer to construct a 400nm thick nickel oxide layer 3, while this scheme uses a low-concentration nickel oxide layer to construct a 300nm nickel oxide layer one, and then uses a high-concentration nickel oxide layer two to construct a 100nm nickel oxide layer two, which are then combined to form the nickel oxide layer 3 of this scheme. The gallium oxide power diodes in control group one and this scheme were irradiated with single particles, and their space charge density distribution and electric field distribution diagrams were obtained, respectively. Figure 5 As shown. Figure 5 a is a schematic diagram of the space charge density distribution of the gallium oxide power diode in control group 1 at a single layer of nickel oxide; Figure 5 b is a schematic diagram of the space charge density distribution of the gallium oxide power diode in this scheme at the double layer of nickel oxide; Figure 5 c is a schematic diagram of the electric field distribution of the gallium oxide power diode in control group 1 at a single layer of nickel oxide. Figure 5 d is a schematic diagram of the electric field distribution of the gallium oxide power diode in this scheme at the double layer of nickel oxide. Through analysis of... Figure 5 Analysis shows that, Figure 5a and Figure 5 c represents the space charge density and electric field distribution inside a low-concentration NiO heterojunction under uniform single-particle irradiation. It can be observed that due to the lower NiO concentration, the electric field at the heterojunction interface is lower; however, the accumulation of irradiation-induced charges in NiO leads to a higher electric field at the NiO / metal interface. With a bilayer NiO structure, the electric field at the heterojunction interface remains almost unchanged, while the distribution of irradiation-induced charges in NiO is expanded, resulting in a more uniform electric field inside the NiO. Figure 5 b) and Figure 5 As shown in d.

[0049] (IV) Study on hole current density and electric field distribution of gallium oxide power diodes with and without trench 21 at heterojunction interface A set of gallium oxide power diodes with monolayer nickel oxide were constructed as described above, serving as a second control group to investigate the impact of the presence or absence of the trench 21 structure on the performance of gallium oxide power diodes. The gallium oxide power diodes in the second control group were manufactured in the same manner as those in this scheme, the only difference being that the gallium oxide power diodes in the second control group lacked the trench 21 structure. The gallium oxide power diodes in the second control group and those in this scheme were irradiated with single particles, and their space charge density distribution and electric field distribution schematic diagrams were obtained, respectively. Figure 6 As shown. Figure 6 a is a schematic diagram of the space charge density distribution of the gallium oxide power diode at the heterojunction interface in control group 2. Figure 6 b is a schematic diagram of the space charge density distribution of the gallium oxide power diode at the heterojunction interface in this scheme; Figure 6 c is a schematic diagram of the electric field distribution of the gallium oxide power diode in control group 2 at the heterojunction interface; Figure 6 Figure d shows the electric field distribution of the gallium oxide power diode at the heterojunction interface in this scheme. Through analysis of... Figure 6 Analysis shows that, Figure 6 a and Figure 6 c represents the hole current density and electric field distribution inside the trenchless 21-structure heterojunction under single-particle irradiation (ion incident position is the center of groove 242). It can be observed that the local current density and electric field are relatively high on the epitaxial layer surface. However, with the trench 21 structure, holes are laterally extracted, mitigating the hole current density and electric field accumulation effect, thus enhancing the device's radiation resistance. Figure 6 b and Figure 6 As shown in d.

[0050] (V) Study on hole current density and electric field distribution at heterojunction interface of gallium oxide power diodes with and without dielectric layer 4 A set of gallium oxide power diodes with a single layer of nickel oxide was constructed as described above, serving as control group three to investigate the effect of the dielectric layer 4 on the performance of gallium oxide power diodes. The gallium oxide power diodes in control group three were manufactured in the same manner as those in this scheme, the only difference being that they lacked the dielectric layer 4. The gallium oxide power diodes in control group three and those in this scheme were irradiated with single particles, and their space charge density distribution and electric field distribution schematic diagrams were obtained, respectively. Figure 7 As shown. Figure 7 a is a schematic diagram of the space charge density distribution of the gallium oxide power diode in control group three at the heterojunction interface; Figure 7 b is a schematic diagram of the space charge density distribution of the gallium oxide power diode at the heterojunction interface in this scheme; Figure 7 c is a schematic diagram of the electric field distribution of the gallium oxide power diode in control group three at the heterojunction interface; Figure 7 Figure d shows the electric field distribution of the gallium oxide power diode at the heterojunction interface in this scheme. Through analysis of... Figure 7 Analysis shows that, Figure 7 a and Figure 7 c represents the space charge density and electric field distribution inside the heterojunction without dielectric layer 4 under single-particle irradiation (ion incident position is the center of groove 41). It can be observed that charge accumulation at the bottom of trench 21 leads to a higher local electric field. However, with dielectric layer 4, the polarization charge of the dielectric capacitor compensates for the irradiation-induced charge, suppressing the charge accumulation effect and reducing the local electric field. Meanwhile, the charge induces an electric field in dielectric layer 4; in other words, dielectric layer 4 shares the electric field at the heterojunction interface. Figure 7 b and Figure 7 As shown in d.

[0051] (VI) Stability Construct a set of gallium oxide power diodes with a single layer of nickel oxide as described above, and use them as control group four. The specific structure of the gallium oxide power diodes in control group four can be found in [reference needed]. Figure 8 As shown. The differences between the gallium oxide power diode of control group four and the gallium oxide power diode of this scheme are as follows: the gallium oxide power diode of control group four lacks the JTE structure, the double-layer nickel oxide layer 3, and the dielectric layer 4. The gallium oxide power diodes of control group three and this scheme were respectively irradiated with tantalum ions, and their respective reverse leakage current versus time curves were obtained, i.e. Figure 9 .in Figure 9 a is a graph showing the change of reverse leakage current of the gallium oxide power diode in control group four over time. Figure 9 b is a graph showing the reverse leakage current of the gallium oxide power diode in this scheme as a function of time. Through analysis of... Figure 9 Analysis shows that linear energy transfer reaches 86 MeV•cm2 Under tantalum ion irradiation of / mg, the single-particle burn-off voltage of the gallium oxide power diode in control group four is only 250V, while the single-particle burn-off voltage of the gallium oxide power diode in this scheme reaches 320V. This proves that the gallium oxide power diode in this scheme has achieved a significant enhancement in resistance to single-particle irradiation by constructing a trench 21 structure in the junction region, setting a double-layer nickel oxide layer 3, and adding a dielectric layer 4.

[0052] The basic principles, main features, and advantages of this invention have been described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection claimed by this invention is defined by the appended claims and their equivalents.

Claims

1. A gallium oxide power diode resistant to single-particle irradiation, characterized in that, It includes: A gallium oxide wafer includes a gallium oxide substrate layer (1) and a gallium oxide epitaxial layer (2) from bottom to top, and the upper surface of the gallium oxide epitaxial layer (2) is provided with multiple trenches (21). A nickel oxide layer (3) is disposed on the upper surface of the gallium oxide epitaxial layer (2) and covers the bottom surface and sidewalls of each trench (21); the nickel oxide layer (3) has multiple protrusions spaced apart along its length, and its two ends are spaced apart from the two sidewalls of the gallium oxide wafer; the nickel oxide layer (3) includes a nickel oxide layer one and a nickel oxide layer two disposed sequentially from bottom to top, the concentration of the nickel oxide layer one is lower than that of the nickel oxide layer two and the thickness is higher than that of the nickel oxide layer two; The dielectric layer (4) is disposed on the upper surface of the nickel oxide layer 2 and wraps around the outer side of the nickel oxide layer 2, forming a groove 1 (41) with the same number as the trench (21); the two sides of the dielectric layer (4) are respectively aligned with the two side walls of the gallium oxide wafer, and the dielectric layer (4) is provided with groove 2 (42) on the upper surface of the protrusion of the nickel oxide layer 2. The groove 2 (42) is used to divide the dielectric layer (4) into a multi-segment structure along its length direction; A cathode (5) is disposed on the lower surface of a gallium oxide substrate layer (1); The anode (6) is disposed on the upper surface of the dielectric layer (4) and fills the first groove (41) and the second groove (42) respectively; the two ends of the anode (6) extend outward along the second groove (42) to partially stack on the upper surface of the outermost dielectric layer (4).

2. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The first groove (41) and the second groove (42) are staggered along the length of the nickel oxide layer (3), and the second groove (42) is symmetrically arranged on the upper surface of the nickel oxide layer with the central axis of the protrusion formed by the second nickel oxide layer as the axis of symmetry.

3. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The second groove (42) divides the dielectric layer (4) into multiple dielectric layers one and two symmetrically arranged dielectric layers two; each dielectric layer one is arranged in a U shape and both ends of the U-shaped opening extend outward; the two dielectric layers two are symmetrically arranged on both sides of the dielectric layer one, and the outer side of the dielectric layer two is aligned with the outer side of the gallium oxide wafer and arranged in a multi-level stepped manner.

4. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The depth of the trench (21) ranges from 400nm to 1200nm.

5. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The thickness of the first nickel oxide layer is 100nm-300nm, and the thickness of the second nickel oxide layer is 50nm-100nm. And / or, the concentration range of the first nickel oxide layer is 0.5 × 10⁻⁶. 19 cm -3 ~1.0×10 19 cm -3 The concentration range of the second nickel oxide layer is 2.0 × 10⁻⁶. 19 cm -3 ~5.0×10 19 cm -3 .

6. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The dielectric layer (4) is a barium titanate layer.

7. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The first nickel oxide layer and the second nickel oxide layer are used to form a double-layer JTE junction termination extension structure between the nickel oxide epitaxial layer (2) and the double-layer JTE junction termination extension structure is used to transfer the irradiation sensitive position in the gallium oxide power diode under single particle irradiation from the edge of the anode (6) to the junction region.

8. The gallium oxide power diode with single-particle irradiation resistance as described in claim 1, characterized in that, The anode (6) is made of Ni / Au alloy; And / or, the cathode (5) is made of Ti / Au alloy.

9. A method for fabricating a gallium oxide power diode resistant to single-particle irradiation as described in any one of claims 1-8, characterized in that, It includes: Provide gallium monoxide wafers; A cathode (5) metal is grown on the back side of a gallium oxide wafer to form a cathode (5). Multiple trenches were formed on the upper surface of a gallium oxide wafer by dry etching using nickel metal as a mask (21); the mask metal was then removed with piranha solution and the wafer was immersed in hot phosphoric acid at 120°C for 3 minutes. Nickel oxide layer 1 and nickel oxide layer 2 were deposited on a gallium oxide wafer using magnetron sputtering, with a thickness ratio of 3:1 between the deposited nickel oxide layer 1 and nickel oxide layer 2. Then, a dielectric layer (4) is deposited on the nickel oxide layer 2 by magnetron sputtering. Finally, anode (6) metal is deposited on the upper surface of dielectric layer (4) using magnetron sputtering process, and grooves one (41) and two (42) are filled to form a gallium oxide power diode resistant to single-particle irradiation.

10. The method for fabricating a gallium oxide power diode resistant to single-particle irradiation as described in claim 9, characterized in that, The gallium oxide wafer is formed by depositing a lightly doped gallium oxide epitaxial layer (2) on the upper surface of a heavily doped gallium oxide substrate (1).

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