Preparation method of tin-terminated diamond and field effect transistor and related products

Abstract

The disclosed embodiments provide a method for preparing tin-terminated diamond and field effect transistors and related products. The grown diamond single crystal epitaxial layer will have uneven stress during the cooling process and achieve self-peeling, so the traditional cutting and grinding process of the diamond single crystal epitaxial layer can be omitted. In addition, the first surface of the peeled diamond single crystal epitaxial layer directly contains the first tin terminal area, and there is no need for a separate preparation process flow of the first tin terminal area, which simplifies the preparation process of the tin terminal area. In addition, the preparation method disclosed in the present invention can obtain two single-sided tin-terminated diamonds at one time, which reduces the processing and preparation cost and time of the diamond single crystal, improves the yield, and is compatible with existing processes. In addition, the first non-tin terminal area and the second non-tin terminal area can be used as isolation areas between subsequent devices. Therefore, when the tin-terminated diamond device is subsequently prepared in the disclosed embodiment, there is no need to isolate the device, which simplifies the process steps.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a method for preparing tin-terminated diamond and a field effect transistor and related products. 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 About, the migration rate can reach 50-3000cm 2 / vs, is considered to be the diamond material with the most application potential. 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 as electrical isolation for hydrogen-terminated diamond devices. Fluorine-terminated diamond has strong hydrophobic properties and a low friction coefficient and is mainly used in coating materials.

[0003] Therefore, it is necessary to develop diamond that has both good conductivity and good stability. Summary of the invention

[0004] In view of this, the embodiments of the present disclosure provide a method for preparing tin-terminated diamond and field effect transistor and related products, so as to improve the conductivity and stability of diamond and reduce the processing and preparation cost and time of diamond.

[0005] The present disclosure provides a method for preparing a tin-terminated diamond and a field effect transistor and related products, and the specific scheme is as follows:

[0006] On the one hand, the present disclosure provides a method for preparing tin-terminated diamond, comprising:

[0007] Depositing a first SnOx film on the surface of the pretreated diamond substrate, and patterning the first SnOx film to form a first SnOx layer including a first SnOx retaining region and a first SnOx removal region; wherein x=1 or 2;

[0008] epitaxially growing a diamond single crystal epitaxial layer on the surface of the first SnOx layer using a microwave plasma chemical vapor deposition device, wherein the diamond single crystal epitaxial layer faces the first surface of the diamond substrate to form a first tin terminal region and a first non-tin terminal region;

[0009] Performing a temperature reduction process inside the microwave plasma chemical vapor deposition device to peel the diamond single crystal epitaxial layer from the first SnOx layer;

[0010] A conductive terminal region and a non-conductive terminal region are formed on the second surface of the diamond single crystal epitaxial layer; wherein the second surface and the first surface are arranged opposite to each other.

[0011] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, forming a conductive terminal region and a non-conductive terminal region on the second surface of the diamond single crystal epitaxial layer specifically includes:

[0012] Depositing a second SnOx film on the second surface of the diamond single crystal epitaxial layer, and patterning the second SnOx film to form a second SnOx layer including a second SnOx retained region and a second SnOx removed region;

[0013] Performing plasma hydrogenation treatment on the diamond single crystal epitaxial layer formed with the second SnOx layer to form a second tin terminal region and a second non-tin terminal region on a second surface of the diamond single crystal epitaxial layer;

[0014] The second SnOx layer on the second surface of the diamond single crystal epitaxial layer is removed by pickling.

[0015] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, the temperature of the plasma hydrogenation treatment is 900-1200° C., the hydrogen flow rate is 400-600 sccm, the gas pressure is 110-130 Torr, and the treatment time is 10-30 min.

[0016] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, the first tin terminal region and the second tin terminal region correspond one to one, and the first non-tin terminal region and the second non-tin terminal region correspond one to one.

[0017] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, after forming the conductive terminal region and the non-conductive terminal region on the second surface of the diamond single crystal epitaxial layer, the method further comprises:

[0018] The diamond single crystal epitaxial layer is horizontally divided by a laser division method.

[0019] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, patterning the first SnOx film to form a first SnOx layer including a first SnOx retained area and a first SnOx removed area specifically includes:

[0020] forming a first photoresist layer on a side of the first SnOx film facing away from the diamond substrate;

[0021] Exposing and developing the first photoresist layer to form a first photoresist pattern including a first photoresist completely retained area and a first photoresist completely removed area; wherein the first photoresist completely retained area corresponds to the first SnOx retained area, and the first photoresist completely removed area corresponds to the first SnOx removed area;

[0022] Using the first photoresist pattern as a mask, the first SnOx film is etched by reactive ion etching technology to form a patterned first SnOx layer;

[0023] The first photoresist pattern is removed.

[0024] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, when the first SnOx film is etched by reactive ion etching technology, the reaction gas introduced into the reactive ion etching equipment is a gas mixture of HBr / Ar, the percentage of Ar in the gas mixture is 0%-100%, the input power is 400-700W, and the gas pressure is 4-10mTorr.

[0025] On the other hand, the embodiments of the present disclosure also provide a tin-terminated diamond, which is obtained by the above-mentioned preparation method provided in the embodiments of the present disclosure.

[0026] On the other hand, the present disclosure also provides a method for preparing a field effect transistor, comprising:

[0027] The tin-terminated diamond is formed by using the above-mentioned method for preparing the tin-terminated diamond provided by the embodiment of the present disclosure;

[0028] Prepare a first source electrode and a first drain electrode on both sides of each of the first tin terminal regions;

[0029] Forming a first gate dielectric layer on the side of the first source and the first drain away from the tin terminal diamond, wherein the first gate dielectric layer covers the middle area of ​​the corresponding first tin terminal area and covers part of the first source and part of the first drain;

[0030] A first gate is formed on a side of the first gate dielectric layer away from the tin-terminated diamond, and the first gate covers a middle region of the first gate dielectric layer.

[0031] In some embodiments, the above preparation method provided in the embodiments of the present disclosure further includes:

[0032] Prepare a second source electrode and a second drain electrode on both sides of each of the second tin terminal regions;

[0033] Forming a second gate dielectric layer on the side of the second source and the second drain away from the tin terminal diamond, the second gate dielectric layer covering the middle area of ​​the corresponding second tin terminal area and covering part of the second source and part of the second drain;

[0034] A second gate is formed on a side of the second gate dielectric layer away from the tin-terminated diamond, and the second gate covers a middle region of the second gate dielectric layer.

[0035] In some embodiments, in the above-mentioned preparation method provided in the embodiment of the present disclosure, after forming the second source electrode and the second drain electrode and before forming the second gate dielectric layer, the method further includes:

[0036] forming a second photoresist layer on a side of the second source electrode and the second drain electrode away from the tin-terminated diamond;

[0037] Exposing and developing the second photoresist layer to form a second photoresist pattern including a second photoresist completely retained area and a second photoresist completely removed area; wherein the second photoresist completely retained area corresponds to the second tin terminal area, and the second photoresist completely removed area corresponds to the second non-tin terminal area;

[0038] Using the second photoresist pattern as a mask, performing oxygen plasma treatment on the second non-tin terminal region to convert the second non-tin terminal region into an oxygen terminal region;

[0039] The second photoresist pattern is removed.

[0040] In some embodiments, in the above preparation method provided by the embodiment of the present disclosure, when the tin-terminated diamond is a double-sided tin-terminated diamond, after forming the second gate, the method further includes:

[0041] The diamond single crystal epitaxial layer in the field effect transistor is horizontally divided by a laser dividing method to form two field effect transistors.

[0042] On the other hand, an embodiment of the present disclosure further provides a field effect transistor, which is obtained using the above-mentioned preparation method provided by an embodiment of the present disclosure.

[0043] 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.

[0044] The beneficial effects of the present disclosure are as follows:

[0045] The disclosed embodiments provide a method for preparing tin-terminated diamond and field effect transistors and related products. A diamond single crystal epitaxial layer is epitaxially grown on a diamond substrate on which a patterned first SnOx layer is formed. The high temperature and gas flow rate in a microwave plasma chemical vapor deposition device can be used to obtain a diamond single crystal epitaxial layer having a first tin terminal region and a first non-tin terminal region on the first surface. Then, during the cooling process inside the microwave plasma chemical vapor deposition device, the grown diamond single crystal epitaxial layer will have uneven stress and self-peel off, thereby eliminating the traditional cutting and grinding process of the diamond single crystal epitaxial layer. In addition, the first surface of the peeled diamond single crystal epitaxial layer directly contains the first tin terminal region, and a separate preparation process flow for the first tin terminal region is not required, thereby simplifying the preparation process flow for the tin terminal region. In addition, a conductive terminal region and a non-conductive terminal region are formed on the second surface of the diamond single crystal epitaxial layer after stripping, thereby obtaining a double-sided conductive terminal diamond, so that two single-sided conductive terminal diamonds can be obtained by laser segmentation technology, that is, the preparation method disclosed in the present invention can obtain two single-sided conductive terminal diamonds at one time, reducing the processing and preparation cost and time of the diamond single crystal, improving the yield rate, and being compatible with existing processes. In addition, the first non-tin terminal region and the non-conductive terminal region can be used as an isolation region between the devices subsequently manufactured. Therefore, when the embodiment of the present disclosure is used to prepare a tin-terminated diamond device (such as a field effect transistor) in the subsequent preparation, there is no need to perform device isolation, which simplifies the process steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic flow chart of a method for preparing tin-terminated diamond provided in an embodiment of the present disclosure;

[0047] Figure 2A-2L They are schematic diagrams of structures corresponding to each step of a method for preparing tin-terminated diamond provided by an embodiment of the present disclosure;

[0048] Figure 3 A schematic flow chart of a method for preparing a field effect transistor provided in an embodiment of the present disclosure;

[0049] Figure 4A-4C They 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;

[0050] Figure 5 for Figure 4C Schematic diagram of the cross section along the AA' direction;

[0051] Figure 6A schematic diagram of the structure of a double-sided field effect transistor provided in an embodiment of the present disclosure;

[0052] Figure 7 for Figure 6 Schematic diagram of the structure of a field-effect transistor obtained by laser segmentation. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiment of the present disclosure clearer, the technical solution of the embodiment of the present disclosure will be clearly and completely described in conjunction with the drawings of the embodiment of the present disclosure. It should be noted that in the drawings, the thickness of the layer, film, panel, area, 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 shape of the figure 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 shape of the area 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 are not intended to illustrate the exact shape of the area, do not reflect the true proportion, and the purpose is only to illustrate the content 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.

[0054] 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.

[0055] 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.

[0056] The present disclosure provides a method for preparing tin-terminated diamond. Figure 1 As shown, including:

[0057] S101, depositing a first SnOx film on the surface of the pretreated diamond substrate, and patterning the first SnOx film to form a first SnOx layer including a first SnOx retained region and a first SnOx removed region; wherein x=1 or 2;

[0058] S102, epitaxially growing a diamond single crystal epitaxial layer on the surface of the first SnOx layer using a microwave plasma chemical vapor deposition device, the diamond single crystal epitaxial layer forming a first tin terminal region and a first non-tin terminal region facing the first surface of the diamond substrate;

[0059] S103, performing a temperature reduction process on the inside of the microwave plasma chemical vapor deposition equipment to peel off the diamond single crystal epitaxial layer from the first SnOx layer;

[0060] S104, forming a conductive terminal region and a non-conductive terminal region on the second surface of the diamond single crystal epitaxial layer; wherein the second surface and the first surface are arranged opposite to each other.

[0061] The above-mentioned preparation method provided by the embodiment of the present disclosure is to epitaxially grow a diamond single crystal epitaxial layer on a diamond substrate formed with a patterned first SnOx layer, and obtain a diamond single crystal epitaxial layer containing a first tin terminal region and a first non-tin terminal region on the first surface through the high temperature and gas flow in the microwave plasma chemical vapor deposition equipment. After that, during the cooling process inside the microwave plasma chemical vapor deposition equipment, the grown diamond single crystal epitaxial layer will have uneven stress and realize self-peeling, so the traditional cutting and grinding process of the diamond single crystal epitaxial layer can be omitted. In addition, the first surface of the peeled diamond single crystal epitaxial layer directly contains the first tin terminal region, and there is no need for a separate preparation process flow of the first tin terminal region, which simplifies the preparation process of the tin terminal region. In addition, a conductive terminal region and a non-conductive terminal region are formed on the second surface of the peeled diamond single crystal epitaxial layer, thereby obtaining a double-sided conductive terminal diamond, so that two single-sided conductive terminal diamonds can be obtained by laser segmentation technology, that is, the preparation method disclosed in the present disclosure can obtain 2 single-sided conductive terminal diamonds at one time, reducing the processing and preparation cost and time of the diamond single crystal, improving the yield rate, and being compatible with the existing process. Furthermore, the first non-tin terminal region and the non-conductive terminal region can be used as isolation regions between subsequently manufactured devices. Therefore, when subsequently preparing tin-terminated diamond devices (such as field effect transistors) in the embodiments of the present disclosure, there is no need to perform device isolation, thereby simplifying the process steps.

[0062] Optionally, the diamond substrate pre-treated in the above step S101 may be a diamond single crystal that has been processed (ie, a diamond substrate) by polishing and cleaning the surface of the diamond single crystal.

[0063] Optionally, the polishing and cleaning of the surface of the diamond single crystal may include: first, cutting and polishing the diamond single crystal so that the surface roughness reaches 0 to 10 nm; second, performing inorganic and organic cleaning on the polished diamond single crystal, and then rinsing it in flowing deionized water and drying it with a nitrogen gun.

[0064] Optionally, inorganic cleaning may include: cleaning the polished diamond single crystal 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.

[0065] Optionally, SnOx may be SnO2 or SnO, and the embodiment of the present disclosure takes SnO2 as an example.

[0066] Specifically, Figure 2AAs shown, the first SnO2 film 2' can be deposited on the surface of the pretreated diamond substrate 1 by electron beam evaporation, thermal evaporation, magnetron sputtering, atomic layer deposition or chemical vapor deposition; the thickness of the first SnO2 film 2' can be 0 to 600nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, etc.

[0067] Specifically, patterning the first SnO2 film 2' to form a first SnO2 layer 2 including a first SnO2 retained region 21 and a first SnO2 removed region 22 may specifically include:

[0068] like Figure 2B As shown, a first photoresist layer 3 is formed on the side of the first SnO2 film 2' facing away from the diamond substrate 1, and the thickness of the first photoresist layer 3 may be 1-10 μm.

[0069] like Figure 2C As shown, the first photoresist layer 3 is exposed and developed to form a first photoresist pattern 3' including a first photoresist completely retained area 31 and a first photoresist completely removed area 32; wherein the first photoresist completely retained area 31 corresponds to the first SnO2 retained area 21, and the first photoresist completely removed area 32 corresponds to the first SnO2 removed area 22.

[0070] like Figure 2D As shown, the first SnO2 film 2 is etched by reactive ion etching (RIE) using the first photoresist pattern 3' as a mask to form a patterned first SnO2 layer 2; 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.

[0071] like Figure 2E As shown, the first photoresist pattern 3 ′ is removed, that is, a first SnO 2 layer 2 including a first SnO 2 retained region 21 and a first SnO 2 removed region 22 is formed.

[0072] like Figure 2FAs shown, a diamond single crystal epitaxial layer 4 is epitaxially grown on the surface of the first SnO2 layer 2 using a microwave plasma chemical vapor deposition device (MPCVD), wherein the temperature in the MPCVD is set to 800°C to 1200°C, the pressure is set to 100 to 200 mbar, and a mixed gas of H2, CH4 and N2 is introduced into the MPCVD, wherein the H2 flow rate is 200 to 600 sccm, the CH4 flow rate is 0 to 100 sccm, and the N2 flow rate is 0.01 to 1 sccm, so that a diamond single crystal epitaxial layer 4 can be laterally heteroepitaxially grown on the diamond substrate 1 formed with the first SnO2 layer 2, and the diamond single crystal epitaxial layer 4 can be grown on the surface of the first SnO2 layer 2. The thickness of the layer 4 can be 300 μm to 1000 μm, for example, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc.; due to the high temperature in the MPCVD, the Sn in the first SnO2 layer 2 undergoes thermal diffusion to replace the C in the diamond single crystal epitaxial layer 4 to form a carbon-tin bond, so that the first surface 41 of the diamond single crystal epitaxial layer 4 facing the diamond substrate 1 can form a first tin terminal region 42 corresponding to the first SnO2 retention region 21 and a first non-tin terminal region 43 corresponding to the first SnO2 removal region 22. Afterwards, the interior of the microwave plasma chemical vapor deposition equipment is cooled, and the grown diamond single crystal epitaxial layer 4 will have uneven stress to achieve self-peeling, so that the diamond single crystal epitaxial layer 4 with the first tin terminal region 42 and the first non-tin terminal region 43 is peeled off from the first SnO2 layer 2.

[0073] like Figure 2G As shown, Figure 2G for Figure 2F A schematic plan view of one side of the diamond single crystal epitaxial layer 4 after peeling, where a first tin terminal region 42 and a first non-tin terminal region 43 are formed.

[0074] In some embodiments, in the above-mentioned preparation method provided by the embodiments of the present disclosure, the conductive terminal region formed in the above-mentioned step S104 may be a second tin terminal region, and the non-conductive terminal region may be a second non-tin terminal region.

[0075] Optionally, forming the second tin terminal region and the second non-tin terminal region may specifically include:

[0076] like Figure 2HAs shown, a second SnO2 film 5' is deposited on the second surface 44 of the diamond single crystal epitaxial layer 4 by electron beam evaporation, thermal evaporation, magnetron sputtering, atomic layer deposition or chemical vapor deposition, and the second surface 44 and the first surface 41 are arranged opposite to each other; optionally, the thickness of the second SnO2 film 5' can be 0 to 600nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, etc.

[0077] like Fig.2I As shown, the second SnO2 film 5' is patterned to form a second SnO2 layer 5 including a second SnO2 retention region 51 and a second SnO2 removal region 52; specifically, the specific steps of forming the second SnO2 layer 5 can be referred to. Figure 2B-2E The steps are not described in detail here.

[0078] like Figure 2J As shown, a plasma hydrogenation treatment is performed on the diamond single crystal epitaxial layer 4 formed with the second SnO2 layer 5 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 110-130 Torr, and the treatment time is 10-30min. In this way, the second surface 44 of the diamond single crystal epitaxial layer 4 corresponding to the second SnO2 retention area 51 is converted into a second tin terminal area 45, and the second SnO2 removal area 52 is converted into a second non-tin terminal area 46 (i.e., a hydrogen terminal area) by utilizing the strong reduction and thermal environment of the hydrogen plasma, that is, a second tin terminal area 45 and a second non-tin terminal area 46 are formed on the second surface 44 of the diamond single crystal epitaxial layer 4.

[0079] like Figure 2K As shown, the second SnO2 layer 5 on the second surface 44 of the diamond single crystal epitaxial layer 4 is removed by pickling to obtain a double-sided tin-terminated diamond with good conductivity. Optionally, the acid solution used for pickling can be diluted hydrochloric acid with a concentration of 2 mol / L, and the cleaning time can be about 20 minutes.

[0080] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, if Figure 2K As shown, the first tin terminal area 42 and the second tin terminal area 45 can correspond one to one, and the first non-tin terminal area 43 and the second non-tin terminal area 46 can correspond one to one; of course, it is not limited to this, as long as the first surface 41 and the second surface 44 form a tin terminal area and a non-tin terminal area respectively.

[0081] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, if Figure 2KAs shown, diamond devices can be directly manufactured on the first surface 41 and the second surface 44 of the double-sided tin-terminated diamond respectively, and then the diamond single crystal epitaxial layer 4 of the double-sided tin-terminated diamond can be horizontally divided by laser segmentation to form two single-sided tin-terminated diamond devices (such as field effect transistors).

[0082] In some embodiments, in the above preparation method provided by the embodiments of the present disclosure, after forming a conductive terminal region (a second tin terminal region) and a non-conductive terminal region (a second non-tin terminal region) on the second surface of the diamond single crystal epitaxial layer, the method may further include:

[0083] like Figure 2L As shown, the diamond single crystal epitaxial layer 4 of the double-sided tin-terminated diamond is horizontally divided by laser division to form two single-sided tin-terminated diamonds; then, a diamond device is made on one side of the tin terminal area of ​​each single-sided tin-terminated diamond.

[0084] It should be noted that the embodiment of the present disclosure takes the conductive terminal region formed in step S104 as the second tin terminal region as an example, but is of course not limited to this. For example, the conductive terminal region can also be a hydrogen terminal region, a silicon terminal region, etc., and the corresponding non-conductive terminal region is a non-hydrogen terminal region, a non-silicon terminal region, and the type of conductive terminal region is selected according to needs.

[0085] In summary, the self-stripping tin-terminated diamond prepared by the embodiment of the present invention does not need to be cut or ground subsequently, and the stripped tin-terminated diamond contains a first tin-terminated region, and does not require a separate tin-terminated surface material preparation process, and can be directly used as a tin-terminated device substrate, providing a new tin-terminated device preparation method, simplifying the tin-terminated device preparation process, and being compatible with existing processes; the first non-tin-terminated region in the stripped tin-terminated diamond can be used as an isolation region for device preparation, and when preparing the tin-terminated device, device isolation is not required, thereby simplifying the process steps; the obtained double-sided tin-terminated diamond can be laser segmented to obtain two single-sided tin-terminated diamonds at one time, thereby reducing the processing and preparation cost and time of the diamond single crystal, and improving the yield and utilization rate.

[0086] Based on the same inventive concept, the disclosed embodiment provides a tin-terminated diamond, such as Figure 2K and Figure 2L As shown, the tin-terminated diamond is prepared by the method for preparing the tin-terminated diamond provided by the embodiment of the present disclosure; specifically, the tin-terminated diamond can be Figure 2K The double-sided tin-terminated diamond shown can also be Figure 2L Single sided tin terminated diamond shown.

[0087] Based on the same inventive concept, the present disclosure provides a method for preparing a field effect transistor, such as Figure 3As shown, including:

[0088] S301, forming tin-terminated diamond by using the preparation method of tin-terminated diamond provided by the embodiment of the present disclosure;

[0089] S302, preparing a first source electrode and a first drain electrode on both sides of each first tin terminal region;

[0090] S303, forming a first gate dielectric layer on the side of the first source and the first drain away from the tin terminal diamond, the first gate dielectric layer covering the middle area of ​​the corresponding first tin terminal area and covering part of the first source and part of the first drain;

[0091] S304 , forming a first gate electrode on a side of the first gate dielectric layer away from the tin-terminated diamond, wherein the first gate electrode covers a middle region of the first gate dielectric layer.

[0092] The method for preparing the above-mentioned field effect transistor provided in the embodiment of the present disclosure adopts the aforementioned method for preparing tin-terminated diamond to form tin-terminated diamond, so it has the same technical effect as the aforementioned method for preparing tin-terminated diamond, and will not be described in detail here.

[0093] Specifically, Figure 4A As shown, a first source S1 and a first drain D1 are prepared on both sides of each first tin terminal region 42; specifically, a layer of photoresist is first coated on the first surface 41, and the photoresist is exposed and developed to expose the first source S1 and the first drain D1 regions, and then a layer of metal material (such as Ti / Au) is deposited by electron beam evaporation, and the thickness can be 0~100nm, and then the remaining photoresist is washed away, and after annealing for 30 minutes, the first source S1 and the first drain D1 that are in ohmic contact with the tin terminal diamond are formed.

[0094] Specifically, Figure 4B As shown, a first gate dielectric layer 6 (the material may be SiO2) is formed on the side of the first source S1 and the first drain D1 away from the tin terminal diamond; specifically, a layer of photoresist is first coated on the surface of the first source S1 and the first drain D1, and the photoresist is exposed and developed to expose the middle area of ​​the first tin terminal area 42 and expose part of the first source S1 and part of the first drain D1, and then SiO2 is deposited, and then the remaining photoresist is washed away, so that the first gate dielectric layer 6 covering the middle area of ​​the corresponding first tin terminal area 42 and covering part of the first source S1 and part of the first drain D1 is formed. The first gate dielectric layer 6 covers part of the first source S1 and part of the first drain D1, which can reduce the electric field and increase the breakdown voltage.

[0095] Specifically, Figure 4CAs shown, first, a layer of photoresist is coated on the surface of the first gate dielectric layer 6, and the photoresist is exposed and developed to expose the middle area of ​​the first gate dielectric layer 6. Then, an electron beam evaporation device is used to deposit a metal material (such as Ti / Au) on the side of the first gate dielectric layer 6 away from the tin terminal diamond, and then the remaining photoresist is washed away, thereby forming a first gate G1 covering the middle area of ​​the first gate dielectric layer 6 and forming a Schottky contact, thereby forming a field effect transistor on the first surface 41.

[0096] like Figure 5 As shown, Figure 5 for Figure 4C Schematic diagram of the cross section along the AA' direction.

[0097] Specifically, Figure 6 As shown, a second source S2 and a second drain D2 can also be prepared on both sides of each second tin terminal region 45 of the second surface 44; a second gate dielectric layer 7 is formed on the side of the second source S2 and the second drain D2 away from the tin terminal diamond, and the second gate dielectric layer 7 covers the middle area of ​​the corresponding second tin terminal region 45 and covers part of the second source S2 and part of the second drain D2; a second gate G2 is formed on the side of the second gate dielectric layer 7 away from the tin terminal diamond, and the second gate G2 covers the middle area of ​​the second gate dielectric layer 7. In this way, a field effect transistor is formed on the second surface 44.

[0098] It should be noted that the method for preparing the second source, the second drain, the second gate dielectric layer and the second gate may refer to the aforementioned method for preparing the first source, the first drain, the first gate dielectric layer and the first gate, and will not be described in detail here.

[0099] In some embodiments, in the above-mentioned preparation method provided by the embodiment of the present disclosure, since the second non-tin terminal region 46 is a hydrogen terminal region, and the hydrogen terminal is conductive, in order to prevent the formed device from leaking electricity, the second non-tin terminal region 46 needs to be converted into an insulating region, for example, after forming the second source and the second drain, and before forming the second gate dielectric layer, it also includes: forming a second photoresist layer on the side of the second source and the second drain away from the tin terminal diamond; exposing and developing the second photoresist layer to form a second photoresist pattern including a second photoresist completely retained region and a second photoresist completely removed region; wherein the second photoresist completely retained region corresponds to the second tin terminal region, and the second photoresist completely removed region corresponds to the second non-tin terminal region; using the second photoresist pattern as a mask, performing oxygen plasma treatment on the second non-tin terminal region to convert the second non-tin terminal region into an oxygen terminal region; and removing the second photoresist pattern. In this way, the second non-tin terminal region 46 is removed by oxygen plasma to form an oxygen terminal region, so that the second non-tin terminal region 46 is an insulating region to prevent device leakage.

[0100] Specifically, the oxygen plasma treatment process may include: using ultraviolet / ozone and oxygen plasma to treat the second non-tin terminal area 46, wherein the gas flow rate of oxygen or ozone is 1-100 sccm, the plasma power is 100-300 W, and the treatment time is 1-60 min.

[0101] Specifically, the first source, the first drain, the first gate dielectric layer and the first gate are fabricated on the first surface 41, and the second source, the second drain, the second gate dielectric layer and the second gate are fabricated on the second surface 44. Figure 2K The first surface 41 and the second surface 44 of the double-sided tin terminal diamond are made as an example, of course, it can also be made in Figure 2L The first surface 41 and the second surface 44 corresponding to each single-sided tin-terminated diamond after cutting are respectively manufactured.

[0102] In some embodiments, in the above-mentioned preparation method provided in the embodiments of the present disclosure, when forming Figure 6 After the structure shown, that is, after forming the second gate G2, it also includes:

[0103] like Figure 7 As shown, the diamond single crystal epitaxial layer 4 in the field effect transistor is horizontally divided by a laser division method to form two field effect transistors.

[0104] Optionally, the laser segmentation adopts a laser cutting method, using a pulsed laser operating at 532nm or 1064nm to horizontally cut the diamond single crystal epitaxial layer through an electronically controlled machine tool.

[0105] Based on the same inventive concept, the present disclosure provides a field effect transistor, such as Figure 5 and Figure 7 As shown, the above field effect transistor is obtained by the preparation method provided by the embodiment of the present disclosure.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] The disclosed embodiments provide a method for preparing tin-terminated diamond and field effect transistors and related products. A diamond single crystal epitaxial layer is epitaxially grown on a diamond substrate on which a patterned first SnOx layer is formed. The high temperature and gas flow rate in a microwave plasma chemical vapor deposition device can be used to obtain a diamond single crystal epitaxial layer having a first tin terminal region and a first non-tin terminal region on the first surface. Then, during the cooling process inside the microwave plasma chemical vapor deposition device, the grown diamond single crystal epitaxial layer will have uneven stress and self-peel off, thereby eliminating the traditional cutting and grinding process of the diamond single crystal epitaxial layer. In addition, the first surface of the peeled diamond single crystal epitaxial layer directly contains the first tin terminal region, and a separate preparation process flow for the first tin terminal region is not required, thereby simplifying the preparation process flow for the tin terminal region. In addition, photolithography technology and plasma hydrogenation treatment process are used on the second surface of the diamond single crystal epitaxial layer after peeling to form a conductive terminal area and a non-conductive terminal area on the second surface, thereby obtaining a double-sided conductive terminal diamond, so that two single-sided conductive terminal diamonds can be obtained by laser segmentation technology, that is, the preparation method disclosed in the present invention can obtain 2 single-sided conductive terminal diamonds at a time, reducing the processing and preparation cost and time of the diamond single crystal, improving the yield rate, and being compatible with the existing process. In addition, the first non-tin terminal area and the non-conductive terminal area can be used as an isolation area between the devices subsequently manufactured. Therefore, when the tin-terminated diamond device is subsequently prepared in the embodiment of the present disclosure, it is not necessary to perform device isolation, which simplifies the process steps.

[0110] 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.

[0111] 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 method for preparing a field effect transistor, characterized in that: include: Depositing a first SnOx film on the surface of the pretreated diamond substrate, and patterning the first SnOx film to form a first SnOx layer including a first SnOx retaining region and a first SnOx removal region; wherein x=1 or 2; epitaxially growing a diamond single crystal epitaxial layer on the surface of the first SnOx layer using a microwave plasma chemical vapor deposition device, wherein the diamond single crystal epitaxial layer faces the first surface of the diamond substrate to form a first tin terminal region and a first non-tin terminal region; Performing a temperature reduction process inside the microwave plasma chemical vapor deposition device to peel the diamond single crystal epitaxial layer from the first SnOx layer; forming a second tin terminal region and a second non-tin terminal region on a second surface of the diamond single crystal epitaxial layer; wherein the second surface and the first surface are arranged opposite to each other; Prepare a first source electrode and a first drain electrode on both sides of each of the first tin terminal regions; Forming a first gate dielectric layer on the side of the first source and the first drain away from the tin terminal diamond, wherein the first gate dielectric layer covers the middle area of ​​the corresponding first tin terminal area and covers part of the first source and part of the first drain; A first gate is formed on a side of the first gate dielectric layer away from the tin-terminated diamond, and the first gate covers a middle region of the first gate dielectric layer.

2. The preparation method according to claim 1, characterized in that The forming of a second tin terminal region and a second non-tin terminal region on the second surface of the diamond single crystal epitaxial layer specifically includes: Depositing a second SnOx film on the second surface of the diamond single crystal epitaxial layer, and patterning the second SnOx film to form a second SnOx layer including a second SnOx retained region and a second SnOx removed region; Performing plasma hydrogenation treatment on the diamond single crystal epitaxial layer formed with the second SnOx layer to form a second tin terminal region and a second non-tin terminal region on a second surface of the diamond single crystal epitaxial layer; The second SnOx layer on the second surface of the diamond single crystal epitaxial layer is removed by pickling.

3. The preparation method according to claim 2, characterized in that: The temperature of the plasma hydrogenation treatment is 900-1200° C., the hydrogen flow rate is 400-600 sccm, the gas pressure is 110-130 Torr, and the treatment time is 10-30 min.

4. The preparation method according to claim 1, characterized in that: Also includes: Prepare a second source electrode and a second drain electrode on both sides of each of the second tin terminal regions; Forming a second gate dielectric layer on the side of the second source and the second drain away from the tin terminal diamond, the second gate dielectric layer covering the middle area of ​​the corresponding second tin terminal area and covering part of the second source and part of the second drain; A second gate is formed on a side of the second gate dielectric layer away from the tin-terminated diamond, and the second gate covers a middle region of the second gate dielectric layer.

5. The preparation method according to claim 4, characterized in that: After forming the second source and the second drain and before forming the second gate dielectric layer, the method further includes: forming a second photoresist layer on a side of the second source electrode and the second drain electrode away from the tin-terminated diamond; Exposing and developing the second photoresist layer to form a second photoresist pattern including a second photoresist completely retained area and a second photoresist completely removed area; wherein the second photoresist completely retained area corresponds to the second tin terminal area, and the second photoresist completely removed area corresponds to the second non-tin terminal area; Using the second photoresist pattern as a mask, performing oxygen plasma treatment on the second non-tin terminal region to convert the second non-tin terminal region into an oxygen terminal region; The second photoresist pattern is removed.

6. The preparation method according to claim 4, characterized in that: After forming the second gate, the method further includes: The diamond single crystal epitaxial layer in the field effect transistor is horizontally divided by a laser dividing method to form two field effect transistors.

7. The preparation method according to claim 1, characterized in that: The first tin terminal region and the second tin terminal region correspond one to one, and the first non-tin terminal region and the second non-tin terminal region correspond one to one.

8. The preparation method according to claim 1, characterized in that: The patterning of the first SnOx film to form a first SnOx layer including a first SnOx retained region and a first SnOx removed region specifically includes: forming a first photoresist layer on a side of the first SnOx film facing away from the diamond substrate; Exposing and developing the first photoresist layer to form a first photoresist pattern including a first photoresist completely retained area and a first photoresist completely removed area; wherein the first photoresist completely retained area corresponds to the first SnOx retained area, and the first photoresist completely removed area corresponds to the first SnOx removed area; Using the first photoresist pattern as a mask, the first SnOx film is etched by reactive ion etching technology to form a patterned first SnOx layer; The first photoresist pattern is removed.

9. The preparation method according to claim 8, characterized in that: When the first SnOx film is etched by the reactive ion etching technology, the reaction gas introduced into the reactive ion etching equipment is a gas mixture of HBr / Ar, the percentage of Ar in the gas mixture is 0%-100%, the input power is 400-700W, and the gas pressure is 4-10m Torr.

10. A field effect transistor, characterized in that: The method is adopted to obtain the product according to any one of claims 1 to 9.

11. An electronic device, characterized in that: Comprising the field effect transistor as claimed in claim 10.

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