A method for manufacturing gallium oxide Schottky diodes with excellent interface properties

Abstract

This invention belongs to the field of semiconductor power device technology, and specifically relates to a method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics. The invention involves etching away surface impurities and contaminants from the gallium oxide epitaxial layer, followed by etching repair and re-surface treatment. Finally, the gallium oxide Schottky diode after anode fabrication undergoes post-annealing at 300℃-350℃ in a nitrogen atmosphere. This significantly passivates defects at the Ni-gallium oxide interface, greatly reduces the adverse effects of Fermi pinning, improves barrier uniformity, and results in near-ideal forward characteristics: an ideality factor of 1.00, an ideal subthreshold swing of 60mV / dec, and significantly improves the device's breakdown voltage and stability.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor power device technology, and specifically relates to a method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics. Background Technology

[0002] β-phase gallium oxide (Ga₂O₃) has become a promising material in the field of power electronics due to its superior material properties. This is due to β-Ga₂O₃'s ultra-wide bandgap (4.5–4.9 eV) and relatively high electron mobility (approximately 200 cm⁻¹). 2 The theoretical critical field strength can reach 8 MV / cm. In addition, β-Ga2O3 devices have easily controllable n-type doping and readily available substrates for molten growth, which makes high-quality homoepitaxy and low-cost devices possible.

[0003] Schottky diodes (SBDs) made from β-Ga₂O₃ have attracted considerable attention due to their ultrafast switching speed and simple fabrication process. However, the presence of impurities and electroactive defects at the Schottky interface can degrade the performance, reliability, and stability of SBDs. Furthermore, interface defects—such as dangling bonds, carbon clusters, and surface roughness—lead to the Fermi pinning effect, reducing the barrier height and creating a non-uniform Schottky barrier height, resulting in premature breakdown and lowering the material limit. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention aims to provide a method for manufacturing gallium oxide Schottky diodes with excellent interface characteristics. By compensating for the surface charge formed by impurities or traps, the method significantly reduces the interface states, forms a uniform Schottky barrier height, and fully complies with the hot electron emission mechanism with an ideal factor of 1.00, thereby improving the breakdown voltage of the device and enhancing the performance and stability of SBDs.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for manufacturing a gallium oxide Schottky diode with excellent interface properties includes the following steps:

[0007] S1: Provides a heavily doped gallium oxide substrate, on which a lightly doped gallium oxide epitaxial layer is formed;

[0008] S2: Clean the surface of the lightly doped gallium oxide epitaxial layer with an organic cleaning solution and an inorganic cleaning solvent;

[0009] S3: Perform inductively coupled plasma etching on the surface of the lightly doped gallium oxide epitaxial layer;

[0010] S4: The surface of the lightly doped gallium oxide epitaxial layer after etching is subjected to etching repair treatment;

[0011] S5: Before the back-side ohmic contact process, a protective Si wafer is deposited on the front side of the device; a cathode metal layer Ti / Au is sputtered on the back side of the heavily doped gallium oxide substrate, followed by ohmic annealing.

[0012] S6: Remove the protective material Si wafer with tetramethylammonium hydroxide; treat the surface of the gallium oxide epitaxial layer with solvent;

[0013] S7: Anode for manufacturing gallium oxide Schottky diodes;

[0014] S8: The gallium oxide Schottky diode after anode fabrication undergoes post-anodizing annealing in a nitrogen atmosphere.

[0015] This invention removes surface impurities and contaminants from the gallium oxide epitaxial layer through etching, followed by etching repair, and then performs nitrogen post-annealing at 350°C on the gallium oxide Schottky diode after anode fabrication. This significantly passivates defects at the Ni-GaO interface, greatly reduces the adverse effects of Fermi pinning, improves barrier uniformity, and results in near-ideal forward characteristics: an ideality factor of 1.00, an ideal subthreshold swing of 60 mV / dec, and significantly improves the device's breakdown voltage and stability.

[0016] In a preferred embodiment of the present invention, in step S1, the heavily doped gallium oxide substrate is Sn or Si doped, and the doping concentration is 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 The lightly doped gallium oxide epitaxial layer has a doping concentration of 1×10⁻⁶. 16 cm -3 -1×10 17 cm -3 .

[0017] As a preferred embodiment of the present invention, the heavily doped gallium oxide substrate is Si-doped with a doping concentration of 5 × 10⁻⁶. 18 cm -3 The lightly doped gallium oxide epitaxial layer is unintentionally doped with a doping concentration of 3×10⁻⁶. 16 cm -3 The epitaxial layer.

[0018] As a preferred embodiment of the present invention, in step S2, the organic cleaning solvents acetone, isopropanol, and deionized water are used for cleaning for 5 minutes each; and the inorganic cleaning solvent with a weight ratio of H2SO4:H2O2 = 3:1 is used for cleaning for 30 minutes.

[0019] As a preferred embodiment of the present invention, in step S3, the etching equipment is an inductively coupled plasma etching device; the power of the etching equipment is 30-150 / 400-1500W for RF / ICP; the etching gas is BCl3 / Cl2 or BCl3 / Ar, and the gas flow ratio is 10 / 10, 60 / 20, or 20 / 5 sccm; the etching pressure is 4.5-15 mTorr; the etching time is 5-10 minutes; and the etching depth is 100-300 nm.

[0020] As a preferred embodiment of the present invention, the etching gas is BCl3 / Cl2, and the gas flow ratio is 60 / 20 cm⁻¹. -3 The etching rate was 150 / 1500W, the etching power was RF / ICP = 150 / 1500W, the etching pressure was 4.5mTorr, the etching depth was 300nm, and the etching time was 10 minutes.

[0021] As a preferred embodiment of the present invention, in step S4, the solvent and treatment time for the etching repair treatment are respectively 1 hour and 30 minutes of treatment with an inorganic cleaning solvent with a weight ratio of H2SO4:H2O2 = 3:1 and 20 to 60 minutes of treatment with tetramethylammonium hydroxide.

[0022] As a preferred embodiment of the present invention, in step S5, the atmosphere for ohmic annealing is a nitrogen atmosphere, the flow rate is 3L / min, the temperature for ohmic annealing is 470°C, and the time for ohmic annealing is 1 minute.

[0023] As a preferred embodiment of the present invention, in step S6, the solvent treatment involves cleaning with acetone, isopropanol, and deionized water, followed by treatment with tetramethylammonium hydroxide solvent for 20-60 minutes, and finally treatment of the surface with an inorganic cleaning solvent with a weight ratio of H2SO4:H2O2 = 3:1 for 1 minute.

[0024] As a preferred embodiment of the present invention, in step S8, the temperature for post-annealing of the gallium oxide Schottky diode after anode fabrication is selected to be 250-350°C.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention removes surface impurities and contaminants from the gallium oxide epitaxial layer through etching, followed by etching repair. The resulting gallium oxide Schottky diode, after anode fabrication, undergoes post-annealing at 350°C in a nitrogen atmosphere. This significantly passivates defects at the Ni-GaO interface, greatly reduces the adverse effects of Fermi pinning, improves barrier uniformity, and results in near-ideal forward characteristics: an ideality factor of 1.00, an ideal subthreshold swing of 60 mV / dec, and significantly improves the device's breakdown voltage and stability. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the implementation of the present invention;

[0028] Figure 2 This is a structural diagram of the present invention;

[0029] Figure 3 (a) Comparison of forward current-voltage tests of gallium oxide Schottky diodes before and after nitrogen annealing treatment at 250°C, 300°C, and 350°C according to the present invention. Figure 3 (b) Comparison of the forward current-voltage test graph after annealing at 350℃ with the thermionic emission model, indicating that the current transport is an ideal case;

[0030] Figure 4 To illustrate the gallium oxide Schottky diodes before and after nitrogen post-annealing treatment at 250℃, 300℃, and 350℃ according to the present invention, at a current density of 10 -5 A / cm 2 Up to 10 0 A / cm 2 A comparison chart of ideal factors and average subthreshold swings across five orders of magnitude;

[0031] Figure 5 The image shows a comparison of the average ideality factor, average subthreshold swing, and Schottky barrier height of 10 gallium oxide Schottky diodes before and after nitrogen post-annealing treatment at 250°C, 300°C, and 350°C according to the present invention.

[0032] Figure 6 The graph shows a comparison of the breakdown voltage of gallium oxide Schottky diodes before and after nitrogen post-annealing treatment at 250℃, 300℃, and 350℃ according to the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0035] like Figure 1 As shown, the method for manufacturing a gallium oxide Schottky diode with excellent interface properties according to the present invention includes the following steps:

[0036] S1: Provides a heavily doped gallium oxide substrate on which a lightly doped gallium oxide epitaxial layer is formed;

[0037] Specifically, the heavily doped gallium oxide substrate can be Sn or Si doped, with a doping concentration of 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 The lightly doped gallium oxide epitaxial layer has a doping concentration of 1×10⁻⁶. 16 cm -3 -1×10 17 cm -3 .

[0038] Preferably, the heavily doped gallium oxide substrate is Si-doped with a doping concentration of 5 × 10⁻⁶. 18 cm -3 The lightly doped gallium oxide epitaxial layer is unintentionally doped with a doping concentration of 3 × 10⁻⁶. 16 cm -3 The epitaxial layer.

[0039] S2: Clean the surface of the lightly doped gallium oxide epitaxial layer with organic and inorganic solvents.

[0040] Specifically, the organic cleaning solvents acetone, isopropanol, and deionized water are used for cleaning for 5 minutes each; the inorganic cleaning solvent is H2SO4 (95wt%):H2O2 (30-35wt%) = (3:1), and the inorganic cleaning time is 30 minutes.

[0041] S3: Perform inductively coupled plasma (ICP) etching on the surface of the lightly doped gallium oxide epitaxial layer.

[0042] Specifically, the etching equipment is an inductively coupled plasma (ICP) etching device; the power of the etching equipment is 30-150 / 400-1500W for RF / ICP; the etching gas is BCl3 / Cl2 or BCl3 / Ar, with a gas flow ratio of 10 / 10, 60 / 20, or 20 / 5 sccm; the etching pressure is 4.5-15 mTorr; the etching time is 5-10 minutes; and the etching depth is 100-300 nm.

[0043] Preferably, the etching gas is BCl3 / Cl2, and the gas flow rate ratio is 60 / 20 cm⁻¹. -3The etching power is RF / ICP = 150 / 1500W, the etching pressure is 4.5mTorr, the etching depth is 300nm, and the etching time is 10 minutes.

[0044] S4: The surface of the lightly doped gallium oxide epitaxial layer after etching is subjected to etching repair treatment.

[0045] Specifically, the solvent and treatment time for the etching repair treatment are H2SO4:H2O2 (3:1) for 1 hour and 30 minutes and tetramethylammonium hydroxide (TMAH) for 20 to 60 minutes.

[0046] Preferably, the TMAH etching repair time is 20 minutes.

[0047] S5: Before the back-side ohmic contact process, a protective Si wafer is deposited on the front side of the device. A cathode metal layer Ti / Au (30 / 200nm) is sputtered on the back side of the heavily doped gallium oxide substrate, followed by ohmic annealing.

[0048] Specifically, the ohmic annealing treatment is performed in a nitrogen atmosphere at a flow rate of 3 L / min, at a temperature of 470°C, and for a duration of 1 minute.

[0049] S6: Remove the protective Si wafer by treating with TMAH for 1 hour and 30 minutes. Treat the surface of the gallium oxide epitaxial layer with a solvent.

[0050] Specifically, the solvent treatment involves cleaning with acetone, isopropanol, and deionized water, then treating with TMAH solvent for 20–60 minutes, and finally treating the surface with H2SO4:H2O2 (3:1) for 1 minute.

[0051] Preferably, the TMAH solvent treatment time is 60 minutes.

[0052] S7: The anode of the gallium oxide Schottky diode is manufactured.

[0053] Specifically, an anode is formed on the treated surface by electron beam evaporation, with the anode metal being Ni / Au (50 / 150nm), and a Schottky contact is formed after stripping.

[0054] Preferably, the anode metal is Ni / Au (50 / 150nm).

[0055] S8: After the gallium oxide / gallium phosphate Schottky diode is manufactured, it undergoes post-anodizing annealing.

[0056] Specifically, the temperature of the post-annealing treatment is 300-350℃, the annealing time is 1 minute, and the annealing treatment is carried out in a nitrogen atmosphere.

[0057] Preferably, the temperature of the post-annealing treatment is 350°C.

[0058] Example 1:

[0059] The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to this embodiment includes the following steps:

[0060] Provides Si doping with a doping concentration of 5×10⁻⁶. 18 cm -3 The substrate on which unintentional doping with a doping concentration of 3×10⁻⁶ is grown. 16 cm -3 The epitaxial layer was etched using a BCl3 / Cl2 gas with a flow rate ratio of 60 / 20 cm⁻¹. -3 The etching power RF / ICP = 150 / 1500W, etching pressure 4.5mTorr, etching depth 300nm, etching time 10 minutes, the solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH, the etching repair times are 1 hour 30 minutes and 20 minutes respectively. Before fabricating the cathode, a protective Si wafer is deposited on the front side. After sputtering to form the cathode, the surface protective Si wafer is removed and surface treatment is performed. The solvents for surface treatment are TMAH and H2SO4:H2O2 (3:1), the treatment times are 1 hour and 1 minute respectively. An anode is formed on the treated surface by electron beam evaporation. The anode metal is Ni / Au (50 / 150nm). The gallium oxide Schottky diode after anode formation is subjected to post-annealing treatment. The post-annealing treatment is performed in a nitrogen atmosphere at 350℃ for 1 minute.

[0061] S1: Provides Si doping with a doping concentration of 5×10⁻⁶. 18 cm -3 The substrate on which unintentional doping with a doping concentration of 3×10⁻⁶ is grown. 16 cm -3 The epitaxial layer.

[0062] S2: Clean the epitaxial wafer with solvents. Clean with acetone, isopropanol, and deionized water for 5 minutes each, then clean with H2SO4:H2O2 (3:1) for 30 minutes.

[0063] S3: Etching the epitaxial wafer surface using ICP process. The etching gas is BCl3 / Cl2 with a flow rate ratio of 60 / 20 cm⁻¹. -3 / min, etching power RF / ICP = 150 / 1500W, etching pressure 4.5mTorr, etching depth 300nm, etching time 10 minutes.

[0064] S4: Solvent treatment to repair surface etching damage. The solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH, and the etching repair times are 1 hour 30 minutes and 20 minutes, respectively.

[0065] S5: A protective Si wafer is deposited on the front side, and the cathode of the gallium oxide Schottky diode is fabricated on the back side of the substrate. A cathode metal layer Ti / Au (30 / 200nm) is sputtered on the back side of the gallium oxide substrate, followed by an ohmic annealing treatment at 470°C for 1 minute in a nitrogen atmosphere.

[0066] S6: Remove the protective Si wafer and perform surface treatment. Remove the protective Si wafer by treating with TMAH for 1 hour and 30 minutes. Treat the surface of the gallium oxide epitaxial layer with solvent. First, clean with acetone, isopropanol, and deionized water respectively, then treat with TMAH solvent for 1 hour, and finally treat the surface with H2SO4:H2O2 (3:1) for 1 minute.

[0067] S7: Anode for manufacturing gallium oxide Schottky diodes. Ni metal has a high barrier height, resulting in a relatively stable Schottky contact with gallium oxide. After annealing, it reacts with the gallium oxide surface, passivating interface defects. Metallic Ni / Au (50 / 150nm) is evaporated onto the treated surface using an electron beam process, and the Schottky contact is formed after peeling. The device structure is as follows. Figure 2 As shown.

[0068] S8: Anneal the gallium oxide Schottky diode after anode fabrication in a nitrogen atmosphere at 350°C for 1 minute.

[0069] Example 2:

[0070] Provide a Sn-doped substrate with a doping concentration of 3 × 10⁻⁶. 18 cm -3 Si doping with a doping concentration of 4 × 10⁻⁶ was grown on the substrate. 16 cm -3 The epitaxial layer was etched using a BCl3 / Ar gas with a flow rate ratio of 20 / 5 cm⁻¹. -3The etching power RF / ICP = 30 / 400W, etching pressure = 15mTorr, etching depth = 100nm, etching time = 5 minutes. The solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH. The etching repair times are 1 hour 30 minutes and 30 minutes, respectively. Before fabricating the cathode, a protective Si wafer is deposited on the front side. After sputtering to form the cathode, the surface protective material is removed from the Si wafer, and surface treatment is performed. The solvents for surface treatment are TMAH and H2SO4:H2O2 (3:1). The treatment times are 30 minutes and 1 minute, respectively. An anode is formed on the treated surface by electron beam evaporation. The anode is a Ni / Au (40 / 100nm) metal. The gallium oxide Schottky diode after anode formation is subjected to post-annealing treatment. The post-annealing treatment is performed in a nitrogen atmosphere at 350℃ for 1 minute.

[0071] S1: Provides Sn doping with a doping concentration of 3×10⁻⁶. 18 cm -3 The substrate on which Si doping is grown at a concentration of 4 × 10⁻⁶ 16 cm -3 The epitaxial layer.

[0072] S2: Clean the epitaxial wafer with solvents. Clean with acetone, isopropanol, and deionized water for 5 minutes each, then clean with H2SO4:H2O2 (3:1) for 30 minutes.

[0073] S3: Etching the epitaxial wafer surface using ICP process. The etching gas is BCl3 / Ar with a flow rate ratio of 20 / 5cm. -3 / min, etching power RF / ICP=100 / 400W, etching pressure is 10mTorr, etching depth is 200nm, etching time is 5 minutes.

[0074] S4: Solvent treatment to repair surface etching damage. The solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH, and the etching repair times are 1 hour 30 minutes and 30 minutes, respectively.

[0075] S5: A protective Si wafer is deposited on the front side, and the cathode of the gallium oxide Schottky diode is fabricated on the back side of the substrate. A cathode metal layer Ti / Au (30 / 200nm) is sputtered on the back side of the gallium oxide substrate, followed by an ohmic annealing treatment at 470°C for 1 minute in a nitrogen atmosphere.

[0076] S6: Remove the protective Si wafer and perform surface treatment. Remove the protective Si wafer by treating with TMAH for 1 hour and 30 minutes. Treat the surface of the gallium oxide epitaxial layer with solvent. First, clean with acetone, isopropanol, and deionized water respectively, then treat with TMAH solvent for 30 minutes, and finally treat the surface with H2SO4:H2O2 (3:1) for 1 minute.

[0077] S7: Anode for fabricating gallium oxide Schottky diodes. Metallic Ni / Au (40 / 100nm) is evaporated onto the treated surface using an electron beam process, and the resulting Schottky contact is formed after lift-off. Device structure as follows... Figure 2 As shown.

[0078] S8: Anneal the gallium oxide Schottky diode after anode fabrication in a nitrogen atmosphere at 350°C for 1 minute.

[0079] Example 3:

[0080] Provides Si doping with a doping concentration of 1×10⁻⁶. 18 cm -3 The substrate is used to grow Sn-doped material with a doping concentration of 6 × 10⁻⁶. 16 cm -3 The epitaxial layer was etched using a BCl3 / Cl2 gas with a flow rate ratio of 10 / 10 cm⁻¹. -3 The etching power RF / ICP = 100 / 400W, etching pressure 10mTorr, etching depth 200nm, etching time 5 minutes, the solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH, the etching repair times are 1 hour 30 minutes and 1 hour respectively. Before manufacturing the cathode, a protective Si wafer is deposited on the front side. After sputtering to form the cathode, the surface protective material is removed and the Si wafer is surface treated. The surface treatment solvents are TMAH and H2SO4:H2O2 (3:1), the treatment times are 20 minutes and 1 minute respectively. An anode is formed on the treated surface by electron beam evaporation. The anode metal is Ni / Au (60 / 200nm). The gallium oxide Schottky diode after anode formation is post-annealed. The post-annealing treatment is performed in a nitrogen atmosphere at 350℃ for 1 minute.

[0081] S1: Provides a substrate Si that is doped with a doping concentration of 1×10⁻⁶. 18 cm -3 Sn doping concentration of 6×10⁻⁶ was grown on the substrate. 16 cm -3 The epitaxial layer.

[0082] S2: Clean the epitaxial wafer with solvents. Clean with acetone, isopropanol, and deionized water for 5 minutes each, then clean with H2SO4:H2O2 (3:1) for 30 minutes.

[0083] S3: Etching the epitaxial wafer surface using ICP process. The etching gas is BCl3 / Cl2 with a flow rate ratio of 10 / 10 cm⁻¹. -3 / min, etching power RF / ICP=100 / 400W, etching pressure is 10mTorr, etching depth is 200nm, etching time is 5 minutes.

[0084] S4: Solvent treatment to repair surface etching damage. The solvents used for surface etching damage repair are H2SO4:H2O2 (3:1) and TMAH, and the etching repair times are 1 hour 30 minutes and 1 hour, respectively.

[0085] S5: A protective Si wafer is deposited on the front side, and the cathode of the gallium oxide Schottky diode is fabricated on the back side of the substrate. A cathode metal layer Ti / Au (30 / 200nm) is sputtered on the back side of the gallium oxide substrate, followed by an ohmic annealing treatment at 470°C for 1 minute in a nitrogen atmosphere.

[0086] S6: Remove the protective Si wafer and perform surface treatment. Remove the protective Si wafer by treating with TMAH for 1 hour and 30 minutes. Treat the surface of the gallium oxide epitaxial layer with solvent. First, clean with acetone, isopropanol, and deionized water respectively, then treat with TMAH solvent for 20 minutes, and finally treat the surface with H2SO4:H2O2 (3:1) for 1 minute.

[0087] S7: Anode for fabricating gallium oxide Schottky diodes. Metallic Ni / Au (60 / 200nm) is evaporated onto the treated surface using an electron beam process, and the resulting Schottky contact is formed after lift-off. Device structure as follows... Figure 2 As shown.

[0088] S8: Anneal the gallium oxide Schottky diode after anode fabrication in a nitrogen atmosphere at 350°C for 1 minute.

[0089] The effectiveness of this invention can be further illustrated by the following measured data:

[0090] I. Test Conditions

[0091] A semiconductor analyzer was selected, and the test voltage for the IV test was set to 0–3V with a test accuracy of 0.02V. The measurement was performed under dark and room temperature conditions.

[0092] II. Test Content

[0093] Thirty gallium oxide Schottky diodes with Ni-containing anode metal prepared by this method without post-annealing were selected. The positive and negative terminals of these devices were sequentially connected to a semiconductor analyzer, and the IV curves of the devices before post-annealing were tested. Then, 30 devices were selected from each of the three post-annealing temperatures (250℃, 300℃, and 350℃) prepared using the method of this invention. The positive and negative terminals of these devices were sequentially connected to a semiconductor analyzer, and the IV curves of the devices with different post-annealing temperatures were tested under the above conditions. The results are as follows: Figure 3 .

[0094] like Figure 3 As shown in (a), the IV curve gradually becomes steeper with increasing annealing temperature, indicating that it is closer to the ideal thermionic emission model. Figure 3 As shown in (b), the annealing at 350°C is consistent with the thermionic emission model, indicating that the current transport is an ideal situation.

[0095] like Figure 4 As shown, at a current density of 10 -5 A / cm 2 Up to 10 -1 A / cm 2 Within four orders of magnitude, the ideal factor and subthreshold swing of the device after annealing at 350℃ can maintain ideal values ​​of 1.0 and 60mV / dec, respectively, indicating very stable and excellent positive characteristics.

[0096] like Figure 5 As shown in (a), the average ideality factor and average subthreshold swing of 10 devices under different annealing conditions are presented, illustrating the stability of devices annealed at 350°C and the optimization of yield as the annealing temperature increases. Figure 5 As shown in (b), the barrier heights obtained from the capacitor voltage (CV) and current voltage (IV) extractions of the device after annealing at 350°C are consistent, indicating a very uniform barrier height and reflecting very high interface quality.

[0097] like Figure 6 As shown, the breakdown voltage of the device under different annealing conditions is displayed. Since the breakdown is a hard breakdown, the breakdown voltage increases because annealing the device at 350°C can avoid additional leakage current at the surface and reduce the risk of hard breakdown at the surface.

[0098] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A method for manufacturing a gallium oxide Schottky diode with excellent interface properties, characterized in that: Includes the following steps: S1: Provides a heavily doped gallium oxide substrate, on which a lightly doped gallium oxide epitaxial layer is formed; S2: Clean the surface of the lightly doped gallium oxide epitaxial layer with an organic cleaning solution and an inorganic cleaning solvent; S3: Perform inductively coupled plasma etching on the surface of the lightly doped gallium oxide epitaxial layer; S4: Perform etching repair treatment on the surface of the lightly doped gallium oxide epitaxial layer after etching; the etching repair treatment is carried out using an inorganic cleaning solvent with a weight ratio of H2SO4:H2O2=3:1 and tetramethylammonium hydroxide. S5: Before the back-side ohmic contact process, a protective Si wafer is deposited on the front side of the device; a cathode metal layer Ti / Au is sputtered on the back side of the heavily doped gallium oxide substrate, followed by ohmic annealing. S6: Remove the protective material Si wafer with tetramethylammonium hydroxide; treat the surface of the gallium oxide epitaxial layer with solvent; S7: Anode for manufacturing gallium oxide Schottky diodes; S8: Perform post-anodizing annealing on the gallium oxide Schottky diode after anode fabrication; the post-anodizing annealing is carried out in a nitrogen atmosphere at a temperature of 250–350°C.

2. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 1, characterized in that: In step S1, the heavily doped gallium oxide substrate is Sn or Si doped with a doping concentration of 1×10⁻⁶. 18 cm -3 -1×10 19 cm -3 The lightly doped gallium oxide epitaxial layer has a doping concentration of 1×10⁻⁶. 16 cm -3 -1×10 17 cm -3 .

3. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 2, characterized in that: The heavily doped gallium oxide substrate is Si-doped with a doping concentration of 5 × 10⁻⁶. 18 cm -3 The lightly doped gallium oxide epitaxial layer is unintentionally doped with a doping concentration of 3×10⁻⁶. 16 cm -3 The epitaxial layer.

4. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 1, characterized in that: In step S2, the machine is cleaned for 5 minutes each with organic cleaning solvents acetone, isopropanol, and deionized water; and then cleaned for 30 minutes with an inorganic cleaning solvent with a weight ratio of H2SO4:H2O2=3:

1.

5. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 1, characterized in that: In step S3, the etching equipment is an inductively coupled plasma etching (ICP) device; the power of the etching equipment is 30–150 / 400–1500 W for RF / ICP; the etching gas is BCl3 / Cl2 or BCl3 / Ar, with a gas flow ratio of 10 / 10, 60 / 20, or 20 / 5 sccm; the etching pressure is 4.5–15 mTorr; the etching time is 5–10 minutes; and the etching depth is 100–300 nm.

6. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 5, characterized in that: The etching process uses BCl3 / Cl2 gas with a flow rate ratio of 60 / 20cm³. -3 The etching rate was 150 / 1500W, the etching power was RF / ICP=150 / 1500W, the etching pressure was 4.5mTorr, the etching depth was 300nm, and the etching time was 10 minutes.

7. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 1, characterized in that: In step S4, the etching repair process takes 1 hour and 30 minutes for inorganic cleaning solvent treatment and 20 to 60 minutes for tetramethylammonium hydroxide treatment.

8. The method for manufacturing a gallium oxide Schottky diode with excellent interface characteristics according to claim 1, characterized in that: In step S5, the ohmic annealing is performed in a nitrogen atmosphere at a flow rate of 3 L / min, at a temperature of 470°C, and for a duration of 1 minute.

9. The method for manufacturing a gallium oxide Schottky diode with excellent interface properties according to claim 1, characterized in that: In step S6, the solvent treatment involves cleaning with acetone, isopropanol, and deionized water, followed by treatment with tetramethylammonium hydroxide solvent for 20–60 minutes, and finally treatment of the surface with an inorganic cleaning solvent with a weight ratio of H2SO4:H2O2=3:1 for 1 minute.

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