Composite conductive terminal diamond and preparation method thereof, field effect transistor and preparation method and device thereof

Abstract

The embodiments of the present disclosure provide a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof. Since at least two different conductive terminals are provided on a diamond single crystal substrate, the problem of poor flexibility and diversity of the traditional single conductive terminal diamond single crystal substrate is solved. When the composite conductive terminal diamond provided by the present disclosure is used as a substrate to manufacture diamond devices (such as field effect transistors), by designing the type of conductive terminal, it is expected that the diamond device will have better conductivity and stability, providing new ideas for the development and application of diamond devices; and the shapes and sizes of the different conductive terminals can be freely designed according to needs and are easy to obtain, which can provide a flexible and diverse conductive substrate for diamond devices.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof. Background Art

[0002] With the rise of ultra-wide bandgap semiconductor materials, diamond has a series of advantages such as large bandgap width, high breakdown field strength, high thermal conductivity, and high carrier mobility. It has the title of the ultimate semiconductor material and has great application potential in high-temperature, high-frequency, and high-power electronic devices. Diamond is a wide bandgap semiconductor material with excellent performance. After its surface is processed, it can form different terminals, such as oxygen terminal, hydrogen terminal, fluorine terminal, etc. Different terminal surfaces have different conductivity. Hydrogen-terminated diamond will form a two-dimensional hole gas about 10 nanometers below its surface, and its hole concentration is between 10 8 ~10 15 cm -2 The migration rate can reach 50~3000cm 2 / vs. However, hydrogen-terminated diamond also has disadvantages such as instability and electrical properties are greatly affected by the environment, which limits its development and application. In recent years, the emergence of silicon-terminated diamond has provided a new idea for solving this problem. However, the preparation process of silicon-terminated surface diamond materials and the device processing flow are complex and the yield is low, resulting in slow development of silicon-terminated surface diamond materials and devices. Oxygen-terminated diamond is an insulating surface that is easy to form and is often used for electrical isolation of hydrogen-terminated diamond devices. Fluorine-terminated diamond has strong hydrophobic properties and a low friction coefficient and is mainly used in coating materials.

[0003] At present, there are many studies on the preparation methods and devices of hydrogen-terminated and silicon-terminated diamonds, but most of them only study hydrogen-terminated diamonds or silicon-terminated diamonds, which are relatively simple and lack diversified preparation methods and research on multi-terminated diamonds. Tin-terminated diamonds are currently less studied. Therefore, it is necessary to develop diversified diamond devices and preparation methods that have both good conductivity and good stability. Summary of the invention

[0004] In view of this, the embodiments of the present disclosure provide a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof, so as to provide diversified diamonds with both good conductivity and excellent stability.

[0005] The embodiments of the present disclosure provide a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof, and the specific scheme is as follows:

[0006] On the one hand, an embodiment of the present disclosure provides a composite conductive terminal diamond, comprising: a diamond single crystal substrate, and at least two different conductive terminals located on the surface of the diamond single crystal substrate; wherein adjacent conductive terminals are in close contact with each other.

[0007] In some embodiments, in the composite conductive terminal diamond provided in the embodiments of the present disclosure, the at least two different conductive terminals include at least two of tin terminals, hydrogen terminals, and silicon terminals.

[0008] In some embodiments, in the above-mentioned composite conductive terminal diamond provided in the embodiments of the present disclosure, the surface of the diamond single crystal substrate has any two conductive terminals among the tin terminal, the hydrogen terminal, and the silicon terminal, and any two of the conductive terminals are alternately arranged along the row and column directions of the diamond single crystal substrate.

[0009] On the other hand, the present disclosure also provides a method for preparing a composite conductive terminal diamond, which is used to prepare the composite conductive terminal diamond provided by the present disclosure, and the preparation method includes:

[0010] forming at least two different patterns on the surface of the pretreated diamond single crystal substrate;

[0011] performing a plasma hydrogenation treatment on the diamond single crystal substrate formed with the at least two different patterns to convert the surface of the diamond single crystal substrate corresponding to each of the pattern positions into different conductive terminals;

[0012] The pattern on the surface of the diamond single crystal substrate is removed by pickling to obtain a composite conductive terminal diamond.

[0013] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the forming of at least two different patterns on the surface of the pre-treated diamond single crystal substrate specifically includes:

[0014] Depositing a MOx thin film on the surface of the pretreated diamond single crystal substrate; wherein M is Sn or Si, and x=1 or 2;

[0015] forming a photoresist layer on a side of the MOx thin film facing away from the diamond single crystal substrate;

[0016] Exposing and developing the photoresist layer to form a photoresist pattern including a photoresist completely retained area and a photoresist completely removed area;

[0017] Using the photoresist pattern as a mask, the MOx film is etched by reactive ion etching technology to form a first pattern where MOx is retained and a blank pattern where MOx is removed;

[0018] The photoresist pattern is removed.

[0019] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, converting the surface of the diamond single crystal substrate corresponding to each of the pattern positions into different conductive terminals specifically includes:

[0020] The surface of the diamond single crystal substrate corresponding to the first pattern position is converted into a tin terminal or a silicon terminal, and the surface of the diamond single crystal substrate corresponding to the blank pattern position is converted into a hydrogen terminal.

[0021] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the pattern on the surface of the diamond single crystal substrate is removed by pickling, specifically comprising:

[0022] The first pattern on the surface of the diamond single crystal substrate is removed by acid washing.

[0023] In some embodiments, in the above-mentioned preparation method provided by the embodiment of the present disclosure, before removing the photoresist pattern, it also includes: depositing a NOx film on the side of the diamond single crystal substrate away from the first pattern with the MOx retention and the blank pattern with the MOx removal formed; wherein N is Sn or Si, and N and M are different elements, and x=1 or 2;

[0024] When the photoresist pattern is removed, a second pattern where NOx is retained is formed at the blank pattern position.

[0025] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, converting the surface of the diamond single crystal substrate corresponding to each of the pattern positions into different conductive terminals specifically includes:

[0026] converting the surface of the diamond single crystal substrate corresponding to the first pattern position into a tin terminal, and converting the surface of the diamond single crystal substrate corresponding to the second pattern position into a silicon terminal;

[0027] Alternatively, the surface of the diamond single crystal substrate corresponding to the first pattern position is converted into a silicon terminal, and the surface of the diamond single crystal substrate corresponding to the second pattern position is converted into a tin terminal.

[0028] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, the pattern on the surface of the diamond single crystal substrate is removed by pickling, specifically comprising:

[0029] The first pattern and the second pattern on the surface of the diamond single crystal substrate are removed by acid washing.

[0030] On the other hand, the present disclosure also provides a field effect transistor, including:

[0031] A composite conductive terminal diamond, comprising a diamond single crystal substrate and at least two different conductive terminals in close contact on the surface of the diamond single crystal substrate, wherein the at least two different conductive terminals in close contact are arranged along a first direction;

[0032] A source electrode and a drain electrode, respectively located on two sides of the at least two different conductive terminals in close contact along the first direction;

[0033] A gate dielectric layer, located on a side of the source and drain away from the composite conductive terminal diamond, the gate dielectric layer covers a region between the source and drain, and covers a portion of the source and drain;

[0034] The gate is located on a side of the gate dielectric layer away from the composite conductive terminal diamond, and the gate covers a middle area of ​​the gate dielectric layer.

[0035] In some embodiments, in the above-mentioned field effect transistor provided by the embodiments of the present disclosure, the at least two different closely connected conductive terminals include at least two of a tin terminal, a hydrogen terminal, and a silicon terminal.

[0036] On the other hand, the present disclosure also provides a method for preparing a field effect transistor, comprising:

[0037] The composite conductive terminal diamond is formed by the above-mentioned preparation method provided by the embodiment of the present disclosure;

[0038] A source electrode and a drain electrode are prepared on both sides of at least two adjacent and closely connected different conductive terminals of the composite conductive terminal diamond arranged along the first direction, and the source electrode and the drain electrode are arranged along the first direction; or, a source electrode and a drain electrode are respectively prepared on both sides of each different conductive terminal of the composite conductive terminal diamond;

[0039] Performing oxygen plasma treatment on the region except the source region, the drain region and the region between the source and the drain, so that the region except the source region, the drain region and the region between the source and the drain is converted into an oxygen terminal isolation region;

[0040] Forming a gate dielectric layer on the side of the source and drain away from the composite conductive terminal diamond, wherein the gate dielectric layer covers the area between the source and drain and covers part of the source and the drain;

[0041] A gate is formed on a side of the gate dielectric layer away from the composite conductive terminal diamond, and the gate covers a middle area of ​​the gate dielectric layer.

[0042] On the other hand, an embodiment of the present disclosure further provides an electronic device, comprising the above-mentioned field effect transistor provided by an embodiment of the present disclosure.

[0043] The beneficial effects of the present disclosure are as follows:

[0044] The embodiments of the present disclosure provide a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof. Since at least two different conductive terminals are provided on a diamond single crystal substrate, the problem of poor flexibility and diversity of the traditional single conductive terminal diamond single crystal substrate is solved. When the composite conductive terminal diamond provided by the present disclosure is used as a substrate to manufacture diamond devices (such as field effect transistors), by designing the type of conductive terminals, it is expected that the diamond devices will have better conductivity and stability, providing new ideas for the development and application of diamond devices. In addition, the shapes and sizes of the different conductive terminals can be freely designed according to needs and are easy to obtain, so a flexible and diverse conductive substrate can be provided for diamond devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A cross-sectional schematic diagram of a composite conductive terminal diamond provided in an embodiment of the present disclosure;

[0046] Figure 2 for Figure 1 A schematic diagram of the central area;

[0047] Figure 3 A schematic diagram of a process for preparing a composite conductive terminal diamond provided in an embodiment of the present disclosure;

[0048] Figure 4A-4F They are schematic diagrams of structures corresponding to each step of a method for preparing a composite conductive terminal diamond provided by an embodiment of the present disclosure;

[0049] Figure 4G-4J They are schematic structural diagrams corresponding to each step of another method for preparing composite conductive terminal diamond provided by an embodiment of the present disclosure;

[0050] Figure 5 is a plan view schematic diagram of a field effect transistor;

[0051] Figure 6 for Figure 5 Schematic diagram of the cross section along the AA' direction;

[0052] Figure 7 A schematic diagram of a method for preparing a field effect transistor provided in an embodiment of the present disclosure;

[0053] Figure 8A-8DThey are schematic structural diagrams corresponding to each step of a method for preparing a field effect transistor provided in an embodiment of the present disclosure;

[0054] Figure 9A-9E They are schematic structural diagrams corresponding to each step of another method for preparing a field effect transistor provided in an embodiment of the present disclosure;

[0055] Fig.10 for Fig.9E Schematic diagram of the cross section along the AA' direction;

[0056] Fig.11 for Fig.9E Schematic diagram of the cross section along CC' direction. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described in conjunction with the drawings of the embodiments of the present disclosure. It should be noted that in the drawings, the thickness of the layers, films, panels, regions, etc. is magnified for clarity. In the present disclosure, exemplary embodiments are described with reference to cross-sectional views of schematic diagrams of idealized embodiments. In this way, deviations from the shapes of the figures as a result of, for example, manufacturing technology and / or tolerances will be expected. Therefore, the embodiments described in the present disclosure should not be interpreted as being limited to the specific shapes of the regions shown in the present disclosure, but include deviations in shape caused by, for example, manufacturing. For example, an area illustrated or described as flat may typically have rough and / or nonlinear features; the illustrated sharp corners may be rounded, etc. Therefore, the areas shown in the figures are schematic in nature, and their sizes and shapes do not represent the exact shapes of the illustrated areas, do not reflect the true proportions, and the purpose is only to illustrate the contents of the present disclosure. And the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of well-known functions and well-known components.

[0058] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Inside", "outside", "upper", "lower", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0059] In the following description, when an element or layer is referred to as being "on" or "connected to" another element or layer, the element or layer may be directly on, directly connected to, or there may be an intermediate element or intermediate layer. When an element or layer is referred to as being "disposed on one side of" another element or layer, the element or layer may be directly on one side of, directly connected to, or there may be an intermediate element or intermediate layer. However, when an element or layer is referred to as being "directly on" or "directly connected to" another element or layer, there are no intermediate elements or intermediate layers. The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0060] The present disclosure provides a composite conductive terminal diamond, such as Figure 1 and Figure 2 As shown, Figure 1 is a cross-sectional diagram of a composite conductive terminal diamond. Figure 2 for Figure 1 A plan view of a partial area in the middle, wherein the composite conductive terminal diamond comprises: a diamond single crystal substrate 1, and at least two different conductive terminals located on the surface of the diamond single crystal substrate 1, for example, comprising a first conductive terminal 11 and a second conductive terminal 12; wherein adjacent conductive terminals are in close contact, and close contact means that adjacent edges of adjacent conductive terminals are in contact, for example, adjacent first conductive terminals 11 and second conductive terminals 12 are in close contact.

[0061] The composite conductive terminal diamond provided in the embodiment of the present disclosure has at least two different conductive terminals on a diamond single crystal substrate, thus solving the problem of poor flexibility and diversity of the traditional single conductive terminal diamond single crystal substrate. When the composite conductive terminal diamond provided by the present disclosure is used as a substrate to manufacture diamond devices (such as field effect transistors), a field effect transistor can have different conductive terminals. By designing the types of conductive terminals, it is expected that the diamond device can have better conductivity and stability, providing new ideas for the development and application of diamond devices. In addition, the shapes and sizes of the different conductive terminals can be freely designed according to needs and are easy to obtain, thus providing a flexible and diverse conductive substrate for diamond devices.

[0062] In some embodiments, in the composite conductive terminal diamond provided in the embodiments of the present disclosure, Figure 1 and Figure 2 As shown, at least two different conductive terminals (e.g., the first conductive terminal 11 and the second conductive terminal 12) may include but are not limited to at least two of tin terminals, hydrogen terminals, and silicon terminals. Optionally, the surface of the diamond single crystal substrate 1 has any two conductive terminals of tin terminals, hydrogen terminals, and silicon terminals. For example, the first conductive terminal 11 is a hydrogen terminal, and the second conductive terminal 12 is a tin terminal; for another example, the first conductive terminal 11 is a hydrogen terminal, and the second conductive terminal 12 is a silicon terminal; for another example, the first conductive terminal 11 is a silicon terminal, and the second conductive terminal 12 is a tin terminal.

[0063] In some embodiments, Figure 1 and Figure 2 As shown, the shapes of the first conductive terminal 11 and the second conductive terminal 12 are both rectangular, but are certainly not limited thereto, and may also be other shapes such as square, circle, ellipse, etc., which can be selected according to needs.

[0064] Specifically, Figure 1 and Figure 2 As shown, when the first conductive terminal 11 is a hydrogen terminal and the second conductive terminal 12 is a tin terminal, the tin-terminated diamond device has better stability. Therefore, the tin-hydrogen dual-terminal diamond provided by the present invention having both a hydrogen terminal and a tin terminal is expected to achieve the production of diamond devices with better conductivity and stability, providing new ideas for the development and application of diamond devices.

[0065] Specifically, Figure 1 and Figure 2As shown, when the first conductive terminal 11 is a hydrogen terminal and the second conductive terminal 12 is a silicon terminal, the silicon element, like the hydrogen element, has a smaller electronegativity than the carbon element, and the electronegativity difference between the bonding atoms in the C-Si structure is even greater than that in the C-H structure. Therefore, silicon-terminated diamond can achieve a higher carrier concentration and surface conductivity than hydrogen-terminated diamond, and diamond devices made of silicon-terminated diamond have better stability. Therefore, compared with traditional hydrogen-terminated diamond devices, silicon-hydrogen dual-terminated diamond is expected to achieve the production of diamond devices with better conductivity and stability, providing new ideas for the development and application of diamond devices.

[0066] Specifically, Figure 1 and Figure 2 As shown, when the first conductive terminal 11 is a silicon terminal and the second conductive terminal 12 is a tin terminal, since silicon, like hydrogen, has a smaller electronegativity than carbon, and the electronegativity difference between the bonding atoms in the C-Si structure is even greater than that in the C-H structure, silicon-terminated diamond can achieve a higher carrier concentration and surface conductivity than hydrogen-terminated diamond, and diamond devices made of tin-terminated diamond have better stability. Therefore, compared with traditional hydrogen-terminated diamond devices, tin-silicon dual-terminated diamond is expected to achieve the production of diamond devices with better conductivity and stability, providing new ideas for the development and application of diamond devices.

[0067] In some embodiments, in the composite conductive terminal diamond provided in the embodiments of the present disclosure, Figure 1 and Figure 2 As shown, any two conductive terminals (such as hydrogen terminals and tin terminals) are alternately arranged along the row direction X and the column direction Y of the diamond single crystal substrate 1; of course, the hydrogen terminals and the silicon terminals can also be alternately arranged along the row direction X and the column direction Y of the diamond single crystal substrate 1, and the silicon terminals and the tin terminals can also be alternately arranged along the row direction X and the column direction Y of the diamond single crystal substrate 1.

[0068] It should be noted that the embodiment of the present disclosure takes the example of the diamond single crystal substrate 1 having two different conductive terminals on its surface. Of course, it can also have three or even more different conductive terminals, and the types of conductive terminals can be designed according to needs.

[0069] Based on the same inventive concept, the present disclosure provides a method for preparing a composite conductive terminal diamond, which is used to prepare the present disclosure. Figure 1 and Figure 2 The composite conductive terminal diamond shown, Figure 3 As shown, the preparation method may include:

[0070] S301, forming at least two different patterns on the surface of the pretreated diamond single crystal substrate;

[0071] S302, performing plasma hydrogenation treatment on the diamond single crystal substrate formed with at least two different patterns, so as to convert the surface of the diamond single crystal substrate corresponding to each pattern position into different conductive terminals;

[0072] S303, removing the pattern on the surface of the diamond single crystal substrate by pickling to obtain a composite conductive terminal diamond.

[0073] The method for preparing the composite conductive terminal diamond provided in the embodiment of the present disclosure can simultaneously obtain a patterned diamond single crystal substrate with at least two conductive terminals on a diamond single crystal substrate, thereby improving production efficiency and reducing costs. In addition, the shapes and sizes of different conductive terminal areas can be freely designed through photolithography technology as needed and are easy to obtain, thereby providing a flexible and diverse conductive substrate for the preparation of diamond devices and providing diversified choices for the preparation of diamond devices.

[0074] Optionally, the diamond single crystal substrate pre-treated in the above step S301 may be a processed diamond single crystal substrate obtained by polishing and cleaning the surface of the diamond single crystal substrate.

[0075] Optionally, the polishing and cleaning of the surface of the diamond single crystal substrate may include: first, cutting and polishing the diamond single crystal substrate so that the surface roughness reaches 0 to 10 nm; second, performing inorganic cleaning and organic cleaning on the polished diamond single crystal substrate, and then rinsing it in flowing deionized water and drying it with a nitrogen gun.

[0076] Optionally, inorganic cleaning may include: cleaning the polished diamond single crystal substrate with a heated mixed solution of sulfuric acid and nitric acid; organic cleaning may include: ultrasonic cleaning with acetone, ethanol or isopropanol and deionized water for 0 to 30 minutes respectively.

[0077] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, at least two different patterns are formed on the surface of the pre-treated diamond single crystal substrate in the above-mentioned step S301, which may specifically include:

[0078] like Figure 4A As shown, a MOx thin film can be deposited on the surface of a pretreated diamond single crystal substrate 1 by electron beam evaporation, thermal evaporation, magnetron sputtering, atomic layer deposition or chemical vapor deposition; wherein M is Sn or Si, and x=1 or 2; for example, a SnO2 thin film 2' is deposited, and the thickness of the SnO2 thin film 2' can be 0 to 600 nm, for example, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, etc.

[0079] like Figure 4BAs shown, a photoresist layer 3 may be formed on the side of the MOx film (SnO2 film 2') facing away from the diamond single crystal substrate 1 by spin coating, and the thickness of the photoresist layer 3 may be 1-10 μm;

[0080] like Figure 4C As shown, the photoresist layer 3 is exposed and developed to form a photoresist pattern 3' including a photoresist completely retained area 31 and a photoresist completely removed area 32;

[0081] like Figure 4D As shown, with the photoresist pattern 3' as a mask, the MOx film (SnO2 film 2') is etched by reactive ion etching (RIE) technology to form a first pattern 21 with MOx (SnO2) retained and a blank pattern 22 with MOx (SnO2) removed; specifically, the reaction gas introduced into the reactive ion etching equipment can be a gas mixture of HBr / Ar (hydrogen bromide / argon), the percentage of Ar in the gas mixture can be 0%-100%, the input power can be 400-700W, and the gas pressure can be 4-10mTorr.

[0082] like Figure 4E As shown, the photoresist pattern 3 ′ may be removed by using a developer, that is, a SnO 2 layer 2 including a first pattern 21 (SnO 2 ) and a blank pattern 22 is formed.

[0083] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, the above-mentioned step S302 converts the surface of the diamond single crystal substrate corresponding to each pattern position into different conductive terminals, which may specifically include:

[0084] like Figure 4F As shown, a diamond single crystal substrate 1 having at least two different patterns (e.g., a first pattern 21 and a blank pattern 22) is subjected to plasma hydrogenation treatment using a microwave plasma chemical vapor deposition system. The temperature of the plasma hydrogenation treatment is 900-1200°C, the hydrogen flow rate is 400-600sccm, the gas pressure is 110-130Torr, and the treatment time is 10-30min. In this way, by utilizing the strong reduction and thermal environment of the hydrogen plasma, the surface of the diamond single crystal substrate 1 corresponding to the position of the first pattern 21 (SnO2) is converted into a tin terminal, which is the second conductive terminal 12, and the surface of the diamond single crystal substrate 1 corresponding to the position of the blank pattern 22 is converted into a hydrogen terminal, which is the first conductive terminal 11, that is, a hydrogen terminal and a tin terminal are formed on the surface of the diamond single crystal substrate 1.

[0085] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, the above-mentioned step S303 of removing the pattern on the surface of the diamond single crystal substrate by pickling may specifically include:

[0086] Finally, the first pattern 21 (SnO2) on the surface of the diamond single crystal substrate 1 is removed by pickling to obtain Figure 1 The tin-hydrogen double-terminated diamond shown. Optionally, the acid solution used for pickling can be dilute hydrochloric acid with a concentration of 2 mol / L, and the cleaning time can be about 20 minutes.

[0087] In this way, through Figure 4A-4F and Figure 1 Sn-H double-terminated diamond can be obtained.

[0088] It should be noted that the disclosed embodiment takes MOx as SnO2 as an example, and the double terminals obtained in this way are hydrogen terminals and tin terminals; of course, MOx can also be SnO, and the double terminals obtained in this way are also hydrogen terminals and tin terminals; MOx can also be SiO2, and the double terminals obtained in this way are hydrogen terminals and silicon terminals; MOx is SnO2, SnO or SiO2, and the corresponding double terminal steps are all Figure 4A-4F and Figure 1 However, the pickling solution used when forming the silicon terminal is 5% hydrofluoric acid, and the cleaning time is 5-10 minutes.

[0089] In some embodiments, in the above-mentioned preparation method provided in the embodiment of the present disclosure, the surface of the diamond single crystal substrate 1 is not limited to forming hydrogen terminals and tin terminals and forming hydrogen terminals and silicon terminals, and tin terminals and silicon terminals can also be formed on the surface of the diamond single crystal substrate 1.

[0090] Specifically, forming the tin terminal and the silicon terminal on the surface of the diamond single crystal substrate 1 may include the following steps:

[0091] First, use Figure 4A-4D A SnO 2 layer 2 including a first pattern 21 and a blank pattern 22 is obtained.

[0092] Secondly, in Figure 4E Before removing the photoresist pattern 3', that is, Figure 4D After that, it also includes: Figure 4G As shown, a NOx film is deposited on the side of the diamond single crystal substrate 1 (i.e., the photoresist pattern 3' side) away from the first pattern 21 with MOx (SnO2) retained and the blank pattern 22 with MOx (SnO2) removed; wherein N is Sn or Si, and N and M are different elements, x=1 or 2; for example, since M is Sn, N is Si, NOx can be SiO2, and a tetraethyl orthosilicate CVD (TEOS-CVD) device can be used to deposit a SiO2 film 4', and the thickness of the SiO2 film 4' can be 0 to 600nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, etc.

[0093] In this way, removing Figure 4G When the photoresist pattern 3' is formed in the first pattern 21, the photoresist pattern 3' removes the SiO2 film 4' on the first pattern 21 and the SiO2 film 4' on the side thereof, and forms a second pattern 41 where NOx (SiO2) is retained at the position of the blank pattern 22, that is, forming Figure 4H The diamond single crystal substrate 1 shown has a first pattern 21 of SnO 2 remaining and a second pattern 41 of SiO 2 remaining.

[0094] Then, a microwave plasma chemical vapor deposition system was used to deposit Figure 4H The diamond single crystal substrate 1 formed with the first pattern 21 (SnO2) and the second pattern 41 (SiO2) is subjected to plasma hydrogenation treatment. The temperature of the plasma hydrogenation treatment is 900-1200°C, the hydrogen flow rate is 400-600sccm, the gas pressure is 110-130Torr, and the treatment time is 10-30min. In this way, the surface of the diamond single crystal substrate 1 corresponding to the position of the first pattern 21 (SnO2) is converted into a tin terminal, which is the second conductive terminal 12, and the surface of the diamond single crystal substrate 1 corresponding to the position of the second pattern (SiO2) is converted into a silicon terminal, which is the first conductive terminal 11, that is, a tin terminal and a silicon terminal are formed on the surface of the diamond single crystal substrate 1, as shown in FIG. Fig. 4I shown.

[0095] Finally, the first pattern 21 (SnO2) and the second pattern 41 (SiO2) on the surface of the diamond single crystal substrate 1 are removed by pickling. Figure 4J As shown, a tin-silicon double-terminated diamond single crystal substrate is obtained. Optionally, the first pattern 21 (SnO2) on the surface of the diamond single crystal substrate 1 is cleaned with dilute hydrochloric acid with a concentration of 2 mol / L for 10-30 minutes, and the second pattern 41 (SiO2) on the surface of the diamond single crystal substrate 1 is cleaned with hydrofluoric acid with a concentration of 5% for 5-10 minutes.

[0096] In this way, through Figure 4A-4D , Figure 4G-4J Sn-Si double-terminated diamond can be obtained.

[0097] It should be noted that, in the embodiment of the present disclosure, when forming the tin-silicon double-terminated diamond, the first pattern 21 formed first is SnO2, and the second pattern 41 formed later is SiO2; of course, the first pattern 21 formed first can also be SiO2, and the second pattern 41 formed later can be SnO2, so that the surface of the diamond single crystal substrate 1 corresponding to the position of the first pattern 21 (SiO2) is converted into a silicon terminal, and the surface of the diamond single crystal substrate 1 corresponding to the position of the second pattern 41 (SnO2) is converted into a tin terminal.

[0098] Based on the same inventive concept, the present disclosure provides a field effect transistor, such as Figure 5 and Figure 6 As shown, Figure 5 is a plan view of a field effect transistor. Figure 6 for Figure 5 The cross-sectional schematic diagram along the AA' direction in FIG. 1 , the field effect transistor comprises:

[0099] The composite conductive terminal diamond 10 comprises a diamond single crystal substrate 1 and at least two different conductive terminals (e.g., a first conductive terminal 11 and a second conductive terminal 12) in close contact on the surface of the diamond single crystal substrate 1, wherein the at least two different conductive terminals (the first conductive terminal 11 and the second conductive terminal 12) in close contact are arranged along a first direction (e.g., the first direction is a row direction X);

[0100] The source S and the drain D are respectively located on two sides of at least two different conductive terminals (the first conductive terminal 11 and the second conductive terminal 12) that are closely connected along a first direction (ie, a row direction X);

[0101] The gate dielectric layer 5 is located on the side of the source electrode S and the drain electrode D away from the composite conductive terminal diamond 10, and the gate dielectric layer 5 covers the area between the source electrode S and the drain electrode D, and covers part of the source electrode S and part of the drain electrode D;

[0102] The gate G is located on a side of the gate dielectric layer 5 away from the composite conductive terminal diamond 10 , and covers the middle area of ​​the gate dielectric layer 5 .

[0103] The above-mentioned field effect transistor provided by the embodiment of the present disclosure adopts the composite conductive terminal diamond provided by the present disclosure as the substrate of the field effect transistor, so one field effect transistor can have different conductive terminals. By designing the type of conductive terminals, it is expected to achieve better conductivity and stability of the field effect transistor, providing new ideas for the development and application of field effect transistors; and the shapes and sizes of different conductive terminals can be freely designed according to needs and are easy to obtain, which can realize the flexibility and diversity of field effect transistors.

[0104] In some embodiments, in the above field effect transistor provided in the embodiments of the present disclosure, if Figure 5 and Figure 6As shown, at least two different conductive terminals in close contact may include but are not limited to at least two of tin terminals, hydrogen terminals, and silicon terminals. Optionally, at least two different conductive terminals in close contact may be any two of tin terminals, hydrogen terminals, and silicon terminals. The embodiment of the present disclosure takes the first conductive terminal 11 and the second conductive terminal 12 as an example. For example, the first conductive terminal 11 is a hydrogen terminal, and the second conductive terminal 12 is a tin terminal; for another example, the first conductive terminal 11 is a hydrogen terminal, and the second conductive terminal 12 is a silicon terminal; for another example, the first conductive terminal 11 is a silicon terminal, and the second conductive terminal 12 is a tin terminal.

[0105] Based on the same inventive concept, the present disclosure provides a method for preparing a field effect transistor, such as Figure 7 As shown, it may include:

[0106] S701, forming a composite conductive terminal diamond using the aforementioned preparation method for composite conductive terminal diamond provided by an embodiment of the present disclosure;

[0107] S702, preparing a source electrode and a drain electrode on both sides of at least two adjacent closely connected different conductive terminals of the composite conductive terminal diamond arranged along the first direction, and the source electrode and the drain electrode are arranged along the first direction; or, preparing a source electrode and a drain electrode on both sides of each different conductive terminal of the composite conductive terminal diamond;

[0108] S703, performing oxygen plasma treatment on the region except the source region, the drain region and the region between the source and the drain, so that the region except the source region, the drain region and the region between the source and the drain is converted into an oxygen terminal isolation region;

[0109] S704, forming a gate dielectric layer on the side of the source and drain away from the composite conductive terminal diamond, wherein the gate dielectric layer covers the area between the source and drain, and covers part of the source and drain;

[0110] S705 , forming a gate on a side of the gate dielectric layer away from the composite conductive terminal diamond, the gate covering a middle region of the gate dielectric layer.

[0111] The method for preparing the above-mentioned field effect transistor provided in the embodiment of the present disclosure can form a field effect transistor with a composite conductive terminal. By designing the type of conductive terminal, it is expected to achieve better conductivity and stability of the field effect transistor, providing new ideas for the development and application of field effect transistors; and the shapes and sizes of different conductive terminals can be freely designed according to needs and are easy to obtain, which can realize the flexibility and diversity of field effect transistors.

[0112] Specifically, through Figure 4A-4F and Figure 1A composite conductive terminal diamond 10 having a hydrogen terminal (a first conductive terminal 11) and a tin terminal (a second conductive terminal 12) is formed, such as Fig. 8A As shown, Fig. 8A for Figure 2 some areas in .

[0113] Specifically, Figure 8B As shown, a source S and a drain D are prepared on both sides of at least two adjacent closely connected different conductive terminals (hydrogen terminals and tin terminals) of a composite conductive terminal diamond arranged along a first direction (e.g., row direction X), and the source S and the drain D are arranged along the first direction (i.e., row direction X); specifically, a layer of photoresist is first coated on one side of the composite conductive terminal diamond having the hydrogen terminal and the tin terminal, and the photoresist is exposed and developed to expose the source S region or the drain D region in the hydrogen terminal and the source S region or the drain D region in the tin terminal, and then a layer of metal material (e.g., Ti / Au) is deposited by electron beam evaporation, and the thickness can be 0-100 nm, and then the remaining photoresist is washed away, and after annealing for 30 minutes, the source S and the drain D that are in ohmic contact with the tin-hydrogen dual-terminal diamond are formed.

[0114] Specifically, Figure 8B Since the hydrogen terminal and the tin terminal are in close contact and both the hydrogen terminal and the tin terminal are conductive terminals, in order to insulate different field effect transistors, it is necessary to convert the conductive area between adjacent field effect transistors into an insulating area, such as Figure 8C As shown, the region other than the source S region, the drain D region and the region between the source S and the drain D is subjected to oxygen plasma treatment, so that the region other than the source S region, the drain D region and the region between the source S and the drain D is converted into an oxygen terminal isolation region 13; specifically, the conversion into the oxygen terminal isolation region may include: forming a photoresist layer on the side of the source S and the drain D away from the composite conductive terminal diamond; exposing and developing the photoresist layer to form a photoresist pattern including a photoresist completely retained region and a photoresist completely removed region; wherein, the photoresist The photoresist completely retained area corresponds to the source S area, the drain D area and the area between the source S and the drain D, and the photoresist completely removed area corresponds to the area other than the source S area, the drain D area and the area between the source S and the drain D; using the photoresist pattern as a mask, the area other than the source S area, the drain D area and the area between the source S and the drain D is treated with oxygen plasma, so that the area other than the source S area, the drain D area and the area between the source S and the drain D is converted into an oxygen terminal isolation area 13; the photoresist pattern is removed. In this way, the field effect transistors formed thereafter are insulated from each other.

[0115] Specifically, the above-mentioned oxygen plasma treatment process may specifically include: using ultraviolet light / ozone and oxygen plasma to treat areas other than the source S area, the drain D area and the area between the source S and the drain D, wherein the gas flow rate of oxygen or ozone is 1~100sccm, the plasma power is 100~300W, and the treatment time is 1~60min.

[0116] Specifically, Fig.8D As shown, a gate dielectric layer 5 (the material may be SiO2) is formed on the side of the source S and the drain D away from the composite conductive terminal diamond, and the gate dielectric layer 5 covers the area between the source S and the drain D, and covers part of the source S and the drain D; specifically, a layer of photoresist is first coated on the surface of the source S and the drain D, and the photoresist is exposed and developed to expose the area between the source S and the drain D and part of the source S and the drain D, and then SiO2 is deposited, and then the remaining photoresist is washed away, so that the gate dielectric layer 5 covering the area between the source S and the drain D and covering part of the source S and the drain D is formed, and the gate dielectric layer 5 covers part of the source S and the drain D, which can reduce the electric field and increase the breakdown voltage.

[0117] Specifically, Figure 5 As shown, a gate G is formed on the side of the gate dielectric layer 5 away from the composite conductive terminal diamond, and the gate G covers the middle area of ​​the gate dielectric layer 5; specifically, the formation of the gate G may include: firstly coating a layer of photoresist on the surface of the gate dielectric layer 5, exposing and developing the photoresist to expose the middle area of ​​the gate dielectric layer 5, and then using an electron beam evaporation device to deposit a metal material (such as Ti / Au) on the side of the gate dielectric layer 5 away from the composite conductive terminal diamond, and then washing away the remaining photoresist, so as to form a gate G covering the middle area of ​​the gate dielectric layer 5 and forming a Schottky contact, so as to form Figure 5 and Figure 6 A field effect transistor with composite conductive termination diamond is shown.

[0118] Specifically, through Figure 4A-4F and Figure 1 A composite conductive terminal diamond 10 having a hydrogen terminal (a first conductive terminal 11) and a tin terminal (a second conductive terminal 12) is formed, such as Fig.9A As shown, Fig.9A for Figure 2 some areas in .

[0119] Specifically, Fig. 9BAs shown, a source S and a drain D are respectively prepared on both sides of each different conductive terminal (such as a hydrogen terminal and a tin terminal) of the composite conductive terminal diamond; specifically, a layer of photoresist is first coated on one side of the composite conductive terminal diamond having a hydrogen terminal and a tin terminal, and the photoresist is exposed and developed to expose the source S and drain D regions in the hydrogen terminal and the source S and drain D regions in the tin terminal, and then a layer of metal material (such as Ti / Au) is deposited by electron beam evaporation with a thickness of 0-100 nm, and then the remaining photoresist is washed away, and after annealing for 30 minutes, a source S and a drain D that are in ohmic contact with the tin-hydrogen dual-terminal diamond are formed.

[0120] Specifically, Fig. 9B Since the hydrogen terminal and the tin terminal are in close contact and both the hydrogen terminal and the tin terminal are conductive terminals, in order to insulate different field effect transistors, it is necessary to convert the conductive area between adjacent field effect transistors into an insulating area, such as Fig. 9C As shown, the region other than the source S region, the drain D region and the region between the source S and the drain D is subjected to oxygen plasma treatment, so that the region other than the source S region, the drain D region and the region between the source S and the drain D is converted into an oxygen terminal isolation region 13; specifically, the conversion into the oxygen terminal isolation region may include: forming a photoresist layer on the side of the source S and the drain D away from the composite conductive terminal diamond; exposing and developing the photoresist layer to form a photoresist pattern including a photoresist completely retained region and a photoresist completely removed region; wherein, the photoresist The photoresist completely retained area corresponds to the source S area, the drain D area and the area between the source S and the drain D, and the photoresist completely removed area corresponds to the area other than the source S area, the drain D area and the area between the source S and the drain D; using the photoresist pattern as a mask, the area other than the source S area, the drain D area and the area between the source S and the drain D is treated with oxygen plasma, so that the area other than the source S area, the drain D area and the area between the source S and the drain D is converted into an oxygen terminal isolation area 13; the photoresist pattern is removed. In this way, the field effect transistors formed thereafter are insulated from each other.

[0121] Specifically, the above-mentioned oxygen plasma treatment process may specifically include: using ultraviolet light / ozone and oxygen plasma to treat areas other than the source S area, the drain D area and the area between the source S and the drain D, wherein the gas flow rate of oxygen or ozone is 1~100sccm, the plasma power is 100~300W, and the treatment time is 1~60min.

[0122] Specifically, Fig.9DAs shown, a gate dielectric layer 5 (the material may be SiO2) is formed on the side of the source S and the drain D away from the composite conductive terminal diamond, and the gate dielectric layer 5 covers the area between the source S and the drain D, and covers part of the source S and the drain D; specifically, a layer of photoresist is first coated on the surface of the source S and the drain D, and the photoresist is exposed and developed to expose the area between the source S and the drain D and part of the source S and the drain D, and then SiO2 is deposited, and then the remaining photoresist is washed away, so that the gate dielectric layer 5 covering the area between the source S and the drain D and covering part of the source S and the drain D is formed, and the gate dielectric layer 5 covers part of the source S and the drain D, which can reduce the electric field and increase the breakdown voltage.

[0123] Specifically, Fig.9E As shown, a gate G is formed on the side of the gate dielectric layer 5 away from the composite conductive terminal diamond, and the gate G covers the middle area of ​​the gate dielectric layer 5; specifically, the formation of the gate G may include: firstly coating a layer of photoresist on the surface of the gate dielectric layer 5, exposing and developing the photoresist to expose the middle area of ​​the gate dielectric layer 5, and then using an electron beam evaporation device to deposit a metal material (such as Ti / Au) on the side of the gate dielectric layer 5 away from the composite conductive terminal diamond, and then washing away the remaining photoresist, so as to form a gate G covering the middle area of ​​the gate dielectric layer 5 and forming a Schottky contact, so as to form Fig.9E A field effect transistor with composite conductive termination diamond is shown.

[0124] like Fig.10 and Fig.11 As shown, Fig.10 for Fig.9E Schematic diagram of the cross section along the AA' direction, Fig.11 for Fig.9E Schematic diagram of the cross section along the CC' direction, that is, field effect transistors with two different conductive terminals can be prepared on a piece of composite conductive terminal diamond.

[0125] It should be noted that the embodiment of the present disclosure takes the first conductive terminal 11 as a hydrogen terminal and the second conductive terminal 12 as a tin terminal as an example; of course, the first conductive terminal 11 can be a hydrogen terminal, and the second conductive terminal 12 can be a silicon terminal. The method of forming the hydrogen terminal and the silicon terminal is the same as the method of forming the hydrogen terminal and the tin terminal. When the hydrogen terminal and the silicon terminal are formed, the corresponding gate G material can be Al, and the material of the gate dielectric layer 5 when the hydrogen terminal and the silicon terminal are formed can be Al2O3. The deposition of the Al2O3 gate dielectric specifically includes: using trimethylaluminum and H2O alternately supplied at 450°C through an ALD process, H2O as an oxidizing agent The thickness of the deposited Al2O3 film is 50-150nm, for example, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, etc.; the first conductive terminal 11 can also be a silicon terminal, and the second conductive terminal 12 can be a tin terminal. When the tin terminal and the silicon terminal are formed, the corresponding gate G material can be Al. The method of forming the tin terminal and the silicon terminal refers to the steps in the aforementioned formation of a composite conductive terminal diamond. When the tin terminal and the silicon terminal are formed, the corresponding gate dielectric layer 5 material can also be Al2O3.

[0126] It should be noted that in the above-mentioned preparation method provided in the embodiment of the present disclosure, the patterning process involved in forming each layer structure may include not only part or all of the process such as deposition, photoresist coating, mask template masking, exposure, development, etching, photoresist stripping, etc., but also other process, which is subject to the graphics of the required composition formed in the actual production process, and is not limited here. For example, a post-baking process may also be included after development and before etching. Among them, the deposition process may be chemical vapor deposition, plasma enhanced chemical vapor deposition or physical vapor deposition, which is not limited here; the mask used in the mask process may be a half-tone mask (Half Tone Mask), a single slit diffraction mask (Single Slit Mask) or a gray tone mask (Gray Tone Mask), which is not limited here; etching may be dry etching or wet etching, which is not limited here.

[0127] Based on the same inventive concept, an embodiment of the present disclosure provides an electronic device, including the above-mentioned field effect transistor provided in the embodiment of the present disclosure. Since the principle of solving the problem by the electronic device is similar to the principle of solving the problem by the above-mentioned field effect transistor, the implementation of the electronic device provided in the embodiment of the present disclosure can refer to the implementation of the above-mentioned field effect transistor provided in the embodiment of the present disclosure, and the repeated parts will not be repeated.

[0128] In some embodiments, the electronic devices provided by the embodiments of the present disclosure may include, but are not limited to: radio frequency amplifiers, mixers, radars, satellites, power supplies, automotive electronics, energy-saving lamps, household appliances, etc. Of course, the electronic devices provided by the present disclosure may include other structures in addition to transistors. For example, when the electronic device is a radar, it also includes: transmitters, antennas, receivers, etc.; when the electronic device is a mixer, it also includes: input ports, output ports, etc.

[0129] The embodiments of the present disclosure provide a composite conductive terminal diamond and a preparation method thereof, a field effect transistor and a preparation method and device thereof. Since at least two different conductive terminals are provided on a diamond single crystal substrate, the problem of poor flexibility and diversity of the traditional single conductive terminal diamond single crystal substrate is solved. When the composite conductive terminal diamond provided by the present disclosure is used as a substrate to manufacture a diamond device (such as a field effect transistor), a field effect transistor can have different conductive terminals. By designing the type of conductive terminals, it is expected that the diamond device can have better conductivity and stability, providing new ideas for the development and application of diamond devices. In addition, the shapes and sizes of the different conductive terminals can be freely designed according to needs and are easy to obtain, so a flexible and diverse conductive substrate can be provided for diamond devices.

[0130] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0131] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. A field effect transistor, characterized in that: include: A composite conductive terminal diamond, comprising a diamond single crystal substrate and at least two different conductive terminals in close contact on the surface of the diamond single crystal substrate, wherein the at least two different conductive terminals in close contact are arranged along a first direction; A source electrode and a drain electrode are respectively located on both sides of the at least two different conductive terminals in close contact along the first direction, and the source electrode and the drain electrode are arranged along the first direction and located on different conductive terminals; A gate dielectric layer, located on a side of the source and drain away from the composite conductive terminal diamond, the gate dielectric layer covers a region between the source and drain, and covers a portion of the source and drain; The gate is located on a side of the gate dielectric layer away from the composite conductive terminal diamond, and the gate covers a middle area of ​​the gate dielectric layer.

2. The field effect transistor according to claim 1, characterized in that The at least two different conductive terminals in close contact include at least two of tin terminals, hydrogen terminals, and silicon terminals.

3. The field effect transistor according to claim 2, characterized in that The at least two different conductive terminals in close contact include any two conductive terminals among the tin terminal, the hydrogen terminal, and the silicon terminal.

4. A method for preparing a field effect transistor, characterized in that: include: forming at least two different patterns on the surface of the pretreated diamond single crystal substrate; performing a plasma hydrogenation treatment on the diamond single crystal substrate formed with the at least two different patterns to convert the surface of the diamond single crystal substrate corresponding to each of the pattern positions into different conductive terminals; Removing the pattern on the surface of the diamond single crystal substrate by pickling to obtain a composite conductive terminal diamond having at least two different conductive terminals in close contact; A source electrode and a drain electrode are prepared on both sides of at least two adjacent and closely connected different conductive terminals arranged along the first direction of the composite conductive terminal diamond, wherein the source electrode and the drain electrode are arranged along the first direction and are located on different conductive terminals; Performing oxygen plasma treatment on the region except the source region, the drain region and the region between the source and the drain, so that the region except the source region, the drain region and the region between the source and the drain is converted into an oxygen terminal isolation region; Forming a gate dielectric layer on the side of the source and drain away from the composite conductive terminal diamond, wherein the gate dielectric layer covers the area between the source and drain and covers part of the source and the drain; A gate is formed on a side of the gate dielectric layer away from the composite conductive terminal diamond, and the gate covers a middle area of ​​the gate dielectric layer.

5. The preparation method according to claim 4, characterized in that: The forming of at least two different patterns on the surface of the pre-treated diamond single crystal substrate specifically includes: Depositing a MOx thin film on the surface of the pretreated diamond single crystal substrate; wherein M is Sn or Si, and x=1 or 2; forming a photoresist layer on a side of the MOx thin film facing away from the diamond single crystal substrate; Exposing and developing the photoresist layer to form a photoresist pattern including a photoresist completely retained area and a photoresist completely removed area; Using the photoresist pattern as a mask, the MOx film is etched by reactive ion etching technology to form a first pattern where MOx is retained and a blank pattern where MOx is removed; The photoresist pattern is removed.

6. The preparation method according to claim 5, characterized in that: The converting the surface of the diamond single crystal substrate corresponding to each pattern position into a different conductive terminal specifically includes: The surface of the diamond single crystal substrate corresponding to the first pattern position is converted into a tin terminal or a silicon terminal, and the surface of the diamond single crystal substrate corresponding to the blank pattern position is converted into a hydrogen terminal.

7. The preparation method according to claim 6, characterized in that: Removing the pattern on the surface of the diamond single crystal substrate by pickling specifically includes: The first pattern on the surface of the diamond single crystal substrate is removed by acid washing.

8. The preparation method according to claim 5, characterized in that: Before removing the photoresist pattern, the method further comprises: depositing a NOx film on a side of the diamond single crystal substrate where the first pattern with MOx retained and the blank pattern with MOx removed are formed; wherein N is Sn or Si, and N and M are different elements, and x=1 or 2; When the photoresist pattern is removed, a second pattern where NOx is retained is formed at the blank pattern position.

9. The preparation method according to claim 8, characterized in that: The converting the surface of the diamond single crystal substrate corresponding to each pattern position into a different conductive terminal specifically includes: converting the surface of the diamond single crystal substrate corresponding to the first pattern position into a tin terminal, and converting the surface of the diamond single crystal substrate corresponding to the second pattern position into a silicon terminal; Alternatively, the surface of the diamond single crystal substrate corresponding to the first pattern position is converted into a silicon terminal, and the surface of the diamond single crystal substrate corresponding to the second pattern position is converted into a tin terminal.

10. The preparation method according to claim 9, characterized in that: Removing the pattern on the surface of the diamond single crystal substrate by pickling specifically includes: The first pattern and the second pattern on the surface of the diamond single crystal substrate are removed by acid washing.

11. An electronic device, characterized in that: Comprising the field effect transistor as described in any one of claims 1 to 3.

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