A high-voltage and high-current diamond lateral Schottky diode and its preparation method

Abstract

The present invention discloses a high-voltage and high-current diamond lateral Schottky diode and a preparation method thereof, belonging to the technical field of semiconductor materials and devices; a high-voltage and high-current diamond lateral Schottky diode is prepared by opening a trapezoidal through hole on a hydrogen-terminated diamond, depositing a Schottky contact layer and an ohmic contact layer on the front of the hydrogen-terminated diamond, and growing polycrystalline diamond on the back of the hydrogen-terminated diamond. The trapezoidal through hole structure in the present invention increases the voltage resistance of the lateral Schottky diode, so that the lateral Schottky diode has good electrical characteristics. At the same time, the present invention prepares a Schottky contact layer and an ohmic contact layer on a thinner hydrogen-terminated diamond, reducing the use cost of the hydrogen-terminated diamond, and then growing polycrystalline diamond on the back as a substrate can play a supporting role. The addition of polycrystalline diamond can further improve the performance of the device while reducing the cost of manufacturing the device.

Description

Technical Field

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

[0002] Efficient, stable and reliable power electronic devices play a vital role in the safe and stable operation of power systems. With the continuous development of power electronic technology, its applications are also increasing. Working conditions such as high temperature, high pressure, and high electric field have put forward higher requirements for the use of devices. Ultra-wide bandgap semiconductor diamond has a power quality factor that is superior to materials such as silicon, silicon carbide, and gallium nitride. Due to its ultra-high thermal conductivity, diamond materials can maintain stable performance at high temperatures and will not produce excessive thermal effects. It is expected to be widely used in the field of power semiconductor devices in the future.

[0003] However, the single-crystal diamond Schottky diode devices currently studied are mainly planar structures, and their breakdown voltage is far lower than the expected value of the material. At the same time, due to the small size and high manufacturing cost of high-quality single-crystal diamond, diamond Schottky diodes are difficult to apply on a large scale. Summary of the invention

[0004] The object of the present invention is to provide a high-voltage and high-current diamond lateral Schottky diode and a preparation method thereof, so as to solve the technical problems of low breakdown voltage and high manufacturing cost of single crystal diamond Schottky diode devices in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a high-voltage, high-current diamond lateral Schottky diode, comprising a hydrogen-terminated diamond; at least two trapezoidal through holes are provided on the hydrogen-terminated diamond, the upper bottom of the trapezoidal through hole is located on the surface of the hydrogen-terminated diamond front side, and the lower bottom of the trapezoidal through hole is located on the surface of the hydrogen-terminated diamond back side; polycrystalline diamond is grown on the back side of the hydrogen-terminated diamond; a Schottky contact layer and an ohmic contact layer are deposited on the front side of the hydrogen-terminated diamond; the Schottky contact layer is located in the front side region of the hydrogen-terminated diamond between the two trapezoidal through holes, and the ohmic contact layer is located in the front side region of the hydrogen-terminated diamond outside the two trapezoidal through holes.

[0007] Furthermore, the ohmic contact layer includes a Pd film and a first chemically inert metal layer; the Pd film is located on the front side of the hydrogen-terminated diamond and has a thickness of 20 nm to 50 nm; the first chemically inert metal layer is located on the Pd film and has a thickness of 80 nm to 150 nm.

[0008] Furthermore, the Schottky contact layer includes an Al film and a second chemically inert metal layer; the Al film is located on the front side of the hydrogen-terminated diamond and has a thickness of 20 nm to 50 nm; the second chemically inert metal layer is located on the Al film and has a thickness of 80 nm to 150 nm.

[0009] Furthermore, the hydrogen-terminated diamond is a hydrogen-terminated single crystal diamond or a hydrogen-terminated polycrystalline diamond, and the thickness of the hydrogen-terminated diamond is 50 μm to 200 μm; the thickness of the polycrystalline diamond is 0 μm to 500 μm.

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

[0011] The hydrogen-terminated diamond is placed in a laser device, and holes are drilled from the back side to the front side to form a trapezoidal through hole with a back side hole size larger than a front side hole size, thereby obtaining a hydrogen-terminated diamond substrate;

[0012] The hydrogen-terminated diamond substrate is cleaned, and a pattern is formed on the back of the hydrogen-terminated diamond substrate using a photolithography process, and then a silicon nitride film is deposited on the back of the hydrogen-terminated diamond substrate using magnetron sputtering or PECVD (Plasma Enhanced Chemical Vapor Deposition);

[0013] After the deposition is completed, the photoresist is removed, and polycrystalline diamond is grown on the silicon nitride film on the back of the hydrogen-terminated diamond substrate by CVD (Chemical Vapor Deposition) to obtain a hydrogen-terminated diamond substrate with polycrystalline diamond;

[0014] Depositing an ohmic contact layer on the area outside two trapezoidal through holes on the front side of the hydrogen-terminated diamond substrate having polycrystalline diamond by using an electron beam evaporation process or a magnetron sputtering process;

[0015] After the deposition is completed, an electron beam evaporation process or a magnetron sputtering process is used to deposit a Schottky contact layer between two trapezoidal through holes on the front side of the hydrogen terminal diamond substrate to prepare a high-voltage and high-current diamond lateral Schottky diode.

[0016] Furthermore, the deposition thickness of the silicon nitride film is the same as the thickness of the hydrogen-terminated diamond.

[0017] Furthermore, in the step of growing polycrystalline diamond on the silicon nitride film on the back of the hydrogen-terminated diamond substrate by CVD, the growth conditions are: pressure 20 Torr ~120 Torr, hydrogen flow rate 300 sccm ~500 sccm, methane flow rate 20 sccm ~40 sccm, temperature 750°C ~1000°C.

[0018] Furthermore, in the step of depositing an ohmic contact layer in the area outside the two trapezoidal through holes on the front side of the hydrogen-terminated diamond substrate having polycrystalline diamond using an electron beam evaporation process or a magnetron sputtering process, before depositing the ohmic contact layer, the front side of the hydrogen-terminated diamond substrate is re-hydrogenated by a CVD method.

[0019] Furthermore, the ohmic contact layer includes a Pd film and a first chemically inert metal layer; the first chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

[0020] Furthermore, the Schottky contact layer includes an Al film and a second chemically inert metal layer; the second chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention discloses a high-voltage and high-current diamond lateral Schottky diode and a preparation method thereof. A high-voltage and high-current diamond lateral Schottky diode is prepared by opening a trapezoidal through hole on a hydrogen-terminated diamond, depositing a Schottky contact layer and an ohmic contact layer on the front of the hydrogen-terminated diamond, and growing polycrystalline diamond on the back of the hydrogen-terminated diamond. The trapezoidal through hole structure in the present invention increases the voltage resistance of the lateral Schottky diode, so that the lateral Schottky diode has good electrical characteristics. At the same time, the present invention prepares a Schottky contact layer and an ohmic contact layer on a thinner hydrogen-terminated diamond, reducing the use cost of the hydrogen-terminated diamond. Then, polycrystalline diamond is grown on the back as a substrate, which can play a supporting role. The addition of polycrystalline diamond can further improve the performance of the device while reducing the cost of manufacturing the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1This is a process flow chart of preparing a high-voltage and high-current diamond lateral Schottky diode according to an embodiment of the present invention;

[0025] Figure 2 A top view of a trapezoidal through hole formed in a hydrogen-terminated diamond according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the structure of a high-voltage and high-current diamond lateral Schottky diode according to an embodiment of the present invention.

[0027] Wherein: 1-polycrystalline diamond; 2-hydrogen-terminated diamond; 3-ohmic contact layer; 4-Schottky contact layer; 5-trapezoidal through hole. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0029] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0030] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0031] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0032] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0034] See also Figure 3The present invention discloses a high-voltage and high-current diamond lateral Schottky diode, comprising a hydrogen-terminated diamond 2; at least two trapezoidal through holes 5 are opened on the hydrogen-terminated diamond 2, the upper bottom of the trapezoidal through hole 5 is located on the front side of the hydrogen-terminated diamond 2, and the lower bottom of the trapezoidal through hole 5 is located on the back side of the hydrogen-terminated diamond 2; polycrystalline diamond 1 is grown on the back side of the hydrogen-terminated diamond 2; a Schottky contact layer 4 and an ohmic contact layer 3 are deposited on the front side of the hydrogen-terminated diamond 2; the Schottky contact layer 4 is located in the front side area of ​​the hydrogen-terminated diamond 2 between the two trapezoidal through holes 5, and the ohmic contact layer 3 is located in the front side area of ​​the hydrogen-terminated diamond 2 outside the two trapezoidal through holes 5.

[0035] In a feasible embodiment of the present invention, the ohmic contact layer 3 includes a Pd film and a first chemically inert metal layer; the Pd film is located on the front of the hydrogen-terminated diamond 2 and has a thickness of 20 nm to 50 nm; the first chemically inert metal layer is located on the Pd film and has a thickness of 80 nm to 150 nm. The Schottky contact layer 4 includes an Al film and a second chemically inert metal layer; the Al film is located on the front of the hydrogen-terminated diamond 2 and has a thickness of 20 nm to 50 nm; the second chemically inert metal layer is located on the Al film and has a thickness of 80 nm to 150 nm.

[0036] In a feasible embodiment of the present invention, the hydrogen-terminated diamond 2 is made of hydrogen-terminated single crystal diamond or hydrogen-terminated polycrystalline diamond, and the thickness of the hydrogen-terminated diamond 2 is 50 μm to 200 μm; the thickness of the polycrystalline diamond 1 is 0 μm to 500 μm (when the thickness of the polycrystalline diamond 1 is 0, that is, the polycrystalline diamond 1 is not epitaxial, the support is reduced, and the pressure resistance is not affected). The first chemically inert metal layer is made of one or more of Au, W, Ir, Pt and Pd; the second chemically inert metal layer is made of one or more of Au, W, Ir, Pt and Pd.

[0037] See also Figure 1 The embodiment of the present invention discloses a method for preparing the above-mentioned high-voltage and high-current diamond lateral Schottky diode, comprising the following steps:

[0038] S1, placing the hydrogen-terminated diamond 2 in a laser device, drilling from the back to the front, forming a trapezoidal through hole 5 whose back hole size is larger than that of the front, and obtaining a hydrogen-terminated diamond substrate, such as Figure 2 As shown;

[0039] S2, cleaning the hydrogen-terminated diamond substrate, patterning the back of the hydrogen-terminated diamond substrate using a photolithography process, and then depositing a layer of silicon nitride film on the back of the hydrogen-terminated diamond substrate using magnetron sputtering or PECVD (Plasma Enhanced Chemical Vapor Deposition);

[0040] In this step, the deposition thickness of the silicon nitride film is the same as the thickness of the hydrogen-terminated diamond 2, which is 50 μm to 200 μm.

[0041] S3, after the deposition is completed, the photoresist is removed, and polycrystalline diamond 1 is grown on the silicon nitride film on the back side of the hydrogen-terminated diamond substrate by CVD (Chemical Vapor Deposition) method to obtain a hydrogen-terminated diamond substrate having polycrystalline diamond 1;

[0042] In this step, the photoresist can be removed by immersing in acetone or N-methylpyrrolidone solution and heating in a water bath or ultrasonic treatment to obtain a metal pattern on the hydrogen-terminated diamond substrate. In the step of growing polycrystalline diamond 1 on the silicon nitride film on the back of the hydrogen-terminated diamond substrate by CVD, the growth conditions are: pressure 20 Torr ~120 Torr, hydrogen flow rate 300 sccm ~500 sccm, methane flow rate 20 sccm ~40 sccm, temperature 750℃~1000℃.

[0043] S4, using an electron beam evaporation process or a magnetron sputtering process, depositing an ohmic contact layer 3 on the area outside the two trapezoidal through holes 5 on the front side of the hydrogen-terminated diamond substrate having the polycrystalline diamond 1;

[0044] In this step, the ohmic contact layer 3 includes a Pd film and a first chemically inert metal layer; the first chemically inert metal layer uses one or more of Au, W, Ir, Pt and Pd, but is not limited to; in addition, before depositing the ohmic contact layer 3, the front side of the hydrogen-terminated diamond substrate is re-hydrogenated by CVD to obtain a good hydrogen termination.

[0045] S5, after the deposition is completed, an electron beam evaporation process or a magnetron sputtering process is used to deposit a Schottky contact layer 4 between two trapezoidal through holes 5 on the front side of the hydrogen terminal diamond substrate to prepare a high-voltage and high-current diamond lateral Schottky diode.

[0046] In this step, the Schottky contact layer 4 includes an Al film and a second chemically inert metal layer; the second chemically inert metal layer is made of one or more materials including but not limited to Au, W, Ir, Pt and Pd.

[0047] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0048] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0049] Embodiment 1:

[0050] 1. Hydrogen-terminated diamond 2 uses hydrogen-terminated single crystal diamond with a thickness of 60 μm;

[0051] 2. Place the hydrogen-terminated diamond 2 in a laser device and drill holes from the back to the front to form two trapezoidal through holes 5 whose back hole size is larger than that of the front;

[0052] 3. Clean the hydrogen-terminated diamond 2 using standard organic and inorganic cleaning processes;

[0053] 4. Patterning photoresist on the back side of the hydrogen-terminated diamond 2 using a photolithography process;

[0054] 5. Use magnetron sputtering to deposit a layer of silicon nitride film on the back of the hydrogen-terminated diamond 2, and the deposition thickness is consistent with the thickness of the hydrogen-terminated diamond 2;

[0055] 6. After the deposition is completed, the hydrogen-terminated diamond substrate with the silicon nitride film is taken out and the photoresist is removed, and then immersed in an acetone solution and heated in a water bath to obtain a silicon nitride pattern on the hydrogen-terminated diamond substrate;

[0056] 7. After removing the photoresist, a hydrogen-terminated diamond 2 filled with a silicon nitride film is left. A polycrystalline diamond 1 is grown on the back of the hydrogen-terminated diamond 2 by a CVD method. The growth conditions are a pressure of 40 Torr, 300 sccm of hydrogen, 20 sccm of methane, and a temperature of 800° C. The thickness of the grown polycrystalline diamond 1 is 150 μm.

[0057] 8. Re-hydrogenate the front side of the hydrogen-terminated diamond substrate by CVD to obtain good hydrogen termination.

[0058] 9. Using an electron beam evaporation process, a Pd film (20 nm) and a first chemically inert metal layer (Au, 90 nm) are patterned and deposited on the upper surface area of ​​the hydrogen-terminated diamond 2 outside the two trapezoidal through holes 5;

[0059] 10. Using an electron beam evaporation process, a layer of Al film (20 nm) and a second chemically inert metal layer (Au, 90 nm) are patterned and deposited on the upper layer of the front area of ​​the hydrogen-terminated diamond 2 between the two trapezoidal through holes 5; and a diamond lateral Schottky diode is fabricated.

[0060] The volt-ampere characteristic of the diamond lateral Schottky diode prepared in this embodiment was tested at 1A / cm 2 The current is used as the basis for device breakdown, and the test results show that the breakdown voltage reaches 1250V.

[0061] Embodiment 2:

[0062] 1. Hydrogen-terminated diamond 2 uses hydrogen-terminated polycrystalline diamond with a thickness of 100 μm;

[0063] 2. Place the hydrogen-terminated diamond 2 in a laser device and drill holes from the back to the front to form two trapezoidal through holes 5 whose back hole size is larger than that of the front;

[0064] 3. Clean the hydrogen-terminated diamond 2 using standard organic and inorganic cleaning processes;

[0065] 4. Patterning photoresist on the back side of the hydrogen-terminated diamond 2 using a photolithography process;

[0066] 5. Use PECVD to deposit a layer of silicon nitride film on the back of the hydrogen-terminated diamond 2, and the deposition thickness is consistent with the thickness of the hydrogen-terminated diamond 2;

[0067] 6. After the deposition is completed, the hydrogen-terminated diamond substrate with the silicon nitride film is taken out and the photoresist is removed, and then immersed in an N-methylpyrrolidone solution for ultrasonic treatment to obtain a silicon nitride pattern on the hydrogen-terminated diamond substrate;

[0068] 7. After removing the photoresist, a hydrogen-terminated diamond 2 filled with a silicon nitride film is left. A polycrystalline diamond 1 is grown on the back of the hydrogen-terminated diamond 2 by a CVD method. The growth conditions are a pressure of 80 Torr, a hydrogen gas of 400 sccm, a methane gas of 30 sccm, and a temperature of 900° C. The thickness of the grown polycrystalline diamond 1 is 300 μm.

[0069] 8. Re-hydrogenate the front side of the hydrogen-terminated diamond substrate by CVD to obtain good hydrogen termination.

[0070] 9. Using a magnetron sputtering process, a Pd film (40 nm) and a first chemically inert metal layer (W, 110 nm) are patterned and deposited on the upper surface of the hydrogen-terminated diamond 2 outside the two trapezoidal through holes 5;

[0071] 10. Using an electron beam evaporation process, a layer of Al film (40 nm) and a second chemically inert metal layer (W, 110 nm) are patterned and deposited on the upper layer of the front area of ​​the hydrogen-terminated diamond 2 between the two trapezoidal through holes 5; completing the production of a diamond lateral Schottky diode.

[0072] The volt-ampere characteristic of the diamond lateral Schottky diode prepared in this embodiment was tested at 1A / cm 2 The current is used as the basis for device breakdown, and the test results show that the breakdown voltage reaches 1100V.

[0073] Embodiment 3:

[0074] 1. Hydrogen-terminated diamond 2 uses hydrogen-terminated single crystal diamond with a thickness of 200 μm;

[0075] 2. Place the hydrogen-terminated diamond 2 in a laser device and drill holes from the back to the front to form two trapezoidal through holes 5 whose back hole size is larger than that of the front;

[0076] 3. Clean the hydrogen-terminated diamond 2 using standard organic and inorganic cleaning processes;

[0077] 4. Patterning photoresist on the back side of the hydrogen-terminated diamond 2 using a photolithography process;

[0078] 5. Use PECVD to deposit a layer of silicon nitride film on the back of the hydrogen-terminated diamond 2, and the deposition thickness is consistent with the thickness of the hydrogen-terminated diamond 2;

[0079] 6. After the deposition is completed, the hydrogen-terminated diamond substrate with the silicon nitride film is taken out and the photoresist is removed, and then immersed in an acetone solution and heated in a water bath to obtain a silicon nitride pattern on the hydrogen-terminated diamond substrate;

[0080] 7. After removing the photoresist, a hydrogen-terminated diamond 2 filled with a silicon nitride film is left. A polycrystalline diamond 1 is grown on the back of the hydrogen-terminated diamond 2 by a CVD method. The growth conditions are a pressure of 100 Torr, a hydrogen gas of 500 sccm, a methane gas of 40 sccm, and a temperature of 950° C. The thickness of the grown polycrystalline diamond 1 is 200 μm.

[0081] 8. Re-hydrogenate the front side of the hydrogen-terminated diamond substrate by CVD to obtain good hydrogen termination.

[0082] 9. Using a magnetron sputtering process, a Pd film (30 nm) and a first chemically inert metal layer (Ir, 120 nm) are patterned and deposited on the upper surface of the hydrogen-terminated diamond 2 outside the two trapezoidal through holes 5;

[0083] 10. A layer of Al film (30 nm) and a second chemically inert metal layer (Ir, 120 nm) are patterned and deposited on the upper layer of the front area of ​​the hydrogen-terminated diamond 2 between the two trapezoidal through holes 5 using a magnetron sputtering process; thus, a diamond lateral Schottky diode is fabricated.

[0084] The volt-ampere characteristic of the diamond lateral Schottky diode prepared in this embodiment was tested at 1A / cm 2 The current is used as the basis for device breakdown, and the test results show that the breakdown voltage reaches 1200V.

[0085] Embodiment 4:

[0086] 1. Hydrogen-terminated diamond 2 uses hydrogen-terminated polycrystalline diamond with a thickness of 150 μm;

[0087] 2. Place the hydrogen-terminated diamond 2 in a laser device and drill holes from the back to the front to form three trapezoidal through holes 5 whose back hole size is larger than that of the front;

[0088] 3. Clean the hydrogen-terminated diamond 2 using standard organic and inorganic cleaning processes;

[0089] 4. Patterning photoresist on the back side of the hydrogen-terminated diamond 2 using a photolithography process;

[0090] 5. Use magnetron sputtering to deposit a layer of silicon nitride film on the back of the hydrogen-terminated diamond 2, and the deposition thickness is consistent with the thickness of the hydrogen-terminated diamond 2;

[0091] 6. After the deposition is completed, the hydrogen-terminated diamond substrate with the silicon nitride film is taken out and the photoresist is removed, and then immersed in an N-methylpyrrolidone solution and heated in a water bath to obtain a silicon nitride pattern on the hydrogen-terminated diamond substrate;

[0092] 7. After removing the photoresist, a hydrogen-terminated diamond 2 filled with a silicon nitride film is left. A polycrystalline diamond 1 is grown on the back of the hydrogen-terminated diamond 2 by a CVD method. The growth conditions are a pressure of 120 Torr, a hydrogen gas of 500 sccm, a methane gas of 40 sccm, and a temperature of 1000° C. The thickness of the grown polycrystalline diamond 1 is 400 μm.

[0093] 8. Re-hydrogenate the front side of the hydrogen-terminated diamond substrate by CVD to obtain good hydrogen termination.

[0094] 9. Using an electron beam evaporation process, a Pd film (50 nm) and a first chemically inert metal layer (Pt, 130 nm) are patterned and deposited on the upper surface area of ​​the hydrogen-terminated diamond 2 outside any two adjacent trapezoidal through holes 5;

[0095] 10. Use electron beam evaporation to pattern-deposit a layer of Al film (50 nm) and a second chemically inert metal layer (Pt, 130 nm) on the upper surface of the hydrogen-terminated diamond 2 between the two adjacent trapezoidal through holes 5 selected in step 9; complete the fabrication of a diamond lateral Schottky diode.

[0096] The volt-ampere characteristic of the diamond lateral Schottky diode prepared in this embodiment was tested at 1A / cm 2 The current is used as the basis for device breakdown, and the test results show that the breakdown voltage reaches 1380V.

[0097] Embodiment 5:

[0098] 1. Hydrogen-terminated diamond 2 uses hydrogen-terminated single crystal diamond with a thickness of 200 μm;

[0099] 2. Place the hydrogen-terminated diamond 2 in a laser device and drill holes from the back to the front to form two trapezoidal through holes 5 whose back hole size is larger than that of the front;

[0100] 3. Clean the hydrogen-terminated diamond 2 using standard organic and inorganic cleaning processes;

[0101] 4. Patterning photoresist on the back side of the hydrogen-terminated diamond 2 using a photolithography process;

[0102] 5. Use magnetron sputtering to deposit a layer of silicon nitride film on the back of the hydrogen-terminated diamond 2, and the deposition thickness is consistent with the thickness of the hydrogen-terminated diamond 2;

[0103] 6. After the deposition is completed, the hydrogen-terminated diamond substrate with the silicon nitride film is taken out and the photoresist is removed, and then it is immersed in an acetone solution for ultrasonic treatment to obtain a silicon nitride pattern on the hydrogen-terminated diamond substrate;

[0104] 7. After removing the photoresist, a hydrogen-terminated diamond 2 filled with a silicon nitride film is left. A polycrystalline diamond 1 is grown on the back of the hydrogen-terminated diamond 2 by a CVD method. The growth conditions are a pressure of 100 Torr, a hydrogen gas of 500 sccm, a methane gas of 40 sccm, and a temperature of 950° C. The thickness of the grown polycrystalline diamond 1 is 200 μm.

[0105] 8. Re-hydrogenate the front side of the hydrogen-terminated diamond substrate by CVD to obtain good hydrogen termination.

[0106] 9. Using an electron beam evaporation process, a Pd film (30 nm) and a first chemically inert metal layer (Pd, 100 nm) are patterned and deposited on the upper surface of the hydrogen-terminated diamond 2 outside the two trapezoidal through holes 5;

[0107] 10. Using an electron beam evaporation process, a layer of Al film (30 nm) and a second chemically inert metal layer (Pd, 100 nm) are patterned and deposited on the upper layer of the front area of ​​the hydrogen-terminated diamond 2 between the two trapezoidal through holes 5; completing the production of a diamond lateral Schottky diode.

[0108] The volt-ampere characteristic of the diamond lateral Schottky diode prepared in this embodiment was tested at 1A / cm 2 The current is used as the basis for device breakdown, and the test results show that the breakdown voltage reaches 1220V.

[0109] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high voltage and high current diamond lateral Schottky diode, characterized in that: The invention comprises a hydrogen terminal diamond (2); at least two trapezoidal through holes (5) are formed on the hydrogen terminal diamond (2), and the trapezoidal through holes (5) are filled with silicon nitride; the upper bottom of the trapezoidal through hole (5) is located on the front side of the hydrogen terminal diamond (2), the lower bottom of the trapezoidal through hole (5) is located on the back side of the hydrogen terminal diamond (2), and the size of the trapezoidal through hole (5) on the back side of the hydrogen terminal diamond (2) is larger than that on the front side; polycrystalline diamond (1) is grown on the back side of the hydrogen terminal diamond (2); a Schottky contact layer (4) and an ohmic contact layer (3) are deposited on the front side of the hydrogen terminal diamond (2); the Schottky contact layer (4) is located in the front side region of the hydrogen terminal diamond (2) between the two trapezoidal through holes (5), and the ohmic contact layer (3) is located in the front side region of the hydrogen terminal diamond (2) outside the two trapezoidal through holes (5).

2. A high-voltage, high-current diamond lateral Schottky diode according to claim 1, characterized in that: The ohmic contact layer (3) comprises a Pd film and a first chemically inert metal layer; the Pd film is located on the front side of the hydrogen-terminated diamond (2) and has a thickness of 20 nm to 50 nm; the first chemically inert metal layer is located on the Pd film and has a thickness of 80 nm to 150 nm.

3. A high-voltage, high-current diamond lateral Schottky diode according to claim 2, characterized in that: The Schottky contact layer (4) comprises an Al film and a second chemically inert metal layer; the Al film is located on the front side of the hydrogen-terminated diamond (2) and has a thickness of 20 nm to 50 nm; the second chemically inert metal layer is located on the Al film and has a thickness of 80 nm to 150 nm.

4. The high-voltage and high-current diamond lateral Schottky diode according to claim 1, characterized in that: The hydrogen-terminated diamond (2) is a hydrogen-terminated single crystal diamond or a hydrogen-terminated polycrystalline diamond, and the thickness of the hydrogen-terminated diamond (2) is 50 μm to 200 μm; the thickness of the polycrystalline diamond (1) is 0 μm to 500 μm.

5. A method for preparing the high-voltage and high-current diamond lateral Schottky diode according to claim 1, characterized in that: The following steps are involved: Placing the hydrogen-terminated diamond (2) in a laser device, and drilling holes from the back side to the front side to form trapezoidal through holes (5) with a back side hole size larger than a front side hole size, thereby obtaining a hydrogen-terminated diamond substrate; Cleaning the hydrogen-terminated diamond substrate, patterning the back of the hydrogen-terminated diamond substrate using a photolithography process, and then depositing a layer of silicon nitride film on the back of the hydrogen-terminated diamond substrate using magnetron sputtering or PECVD; After the deposition is completed, the photoresist is removed, and polycrystalline diamond (1) is grown on the silicon nitride film on the back side of the hydrogen-terminated diamond substrate by a CVD method to obtain a hydrogen-terminated diamond substrate having polycrystalline diamond (1); Using an electron beam evaporation process or a magnetron sputtering process, an ohmic contact layer (3) is deposited on the area outside the two trapezoidal through holes (5) on the front side of the hydrogen-terminated diamond substrate having the polycrystalline diamond (1); After the deposition is completed, an electron beam evaporation process or a magnetron sputtering process is used to deposit a Schottky contact layer (4) between two trapezoidal through holes (5) on the front side of the hydrogen terminal diamond substrate, thereby preparing a high-voltage and high-current diamond lateral Schottky diode.

6. The method for preparing a high-voltage and high-current diamond lateral Schottky diode according to claim 5, characterized in that: The deposition thickness of the silicon nitride film is the same as the thickness of the hydrogen-terminated diamond (2).

7. The method for preparing a high-voltage and high-current diamond lateral Schottky diode according to claim 5, characterized in that: In the step of growing polycrystalline diamond (1) on the silicon nitride film on the back side of the hydrogen-terminated diamond substrate by CVD, the growth conditions are: pressure 20 Torr ~ 120 Torr, hydrogen flow rate 300 sccm ~ 500 sccm, methane flow rate 20 sccm ~ 40 sccm, temperature 750°C ~ 1000°C.

8. The method for preparing a high-voltage and high-current diamond lateral Schottky diode according to claim 5, characterized in that: In the step of depositing an ohmic contact layer (3) on the area outside the two trapezoidal through holes (5) on the front side of a hydrogen-terminated diamond substrate having polycrystalline diamond (1) using an electron beam evaporation process or a magnetron sputtering process, before depositing the ohmic contact layer (3), the front side of the hydrogen-terminated diamond substrate is hydrogenated again using a CVD method.

9. The method for preparing a high-voltage and high-current diamond lateral Schottky diode according to claim 5, characterized in that: The ohmic contact layer (3) comprises a Pd film and a first chemically inert metal layer; the first chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

10. The method for preparing a high-voltage and high-current diamond lateral Schottky diode according to claim 5, characterized in that: The Schottky contact layer (4) comprises an Al film and a second chemically inert metal layer; the second chemically inert metal layer is one or more of Au, W, Ir, Pt and Pd.

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