Semiconductor structure and preparation method thereof

Abstract

The invention provides a semiconductor structure and a preparation method thereof. The preparation method comprises the following steps: providing a substrate; preparing a first semiconductor layer on the surface of the substrate, wherein the first semiconductor layer is a diamond layer with a first doping type; preparing a second semiconductor layer on the surface of the first semiconductor layer, wherein the second semiconductor layer is a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other one is P-type doping. And the PN junction with excellent electrical properties can be prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor, and particularly relates to a semiconductor structure and a preparation method thereof. BACKGROUND

[0002] PN junction is a core component of various semiconductor devices, such as rectifier diode, voltage regulator diode, light emitting diode, junction field effect transistor and insulated gate field effect transistor, etc. These devices widely use the unidirectional conduction characteristics, breakdown characteristics and photoelectric effect principles of PN junction, and are widely used in the fields of electronic, optoelectronic and power devices. However, in silicon-based semiconductors, the performance of PN junction is limited by the physical properties of silicon material such as band gap width, which leads to the inability to meet the increasing performance requirements in high-speed and high-power devices. In order to meet the requirements of higher working frequency, power density and reliability, the development of new materials and structures, especially wide bandgap semiconductor materials, has become an important direction of current technology development.

[0003] Diamond is a semiconductor material with wide band gap (~5.5eV), high thermal conductivity (20W / cm·K), high breakdown field strength and excellent chemical stability. Its electron mobility is about three times that of silicon (Si), and its hole mobility is about four times that of silicon. Due to its excellent physical properties, diamond has a very wide application prospect in high temperature, radiation and other extreme environments. In the field of electronic devices, diamond as a "ultimate semiconductor" has shown great application potential.

[0004] The preparation process of p-type diamond semiconductor is relatively mature, and the preparation process of n-type doped diamond still has some deficiencies. At present, the common n-type diamond material is usually prepared by MPCVD process to prepare phosphorus doped diamond. However, the electron mobility and electron concentration of the phosphorus doped diamond prepared by MPCVD process are low, and the general electron mobility is about 670 cm-2, and the general electron concentration is about 1014cm-3. . (Reference: [Stenger I, Pinault-Thaury MA,Temahuki N, et al. Electron mobility in (100) homoepitaxial layers of phosphorus-doped diamond[J]. Journal of Applied Physics, 2021, 129(10).]) In addition, there is also a technology for realizing n-type diamond semiconductors through MPCVD co-doping (boron-sulfur co-doping) method, such as the method described in the patent [A co-doped diamond and preparation method and semiconductor material and device]. Boron-nitrogen co-doped diamond can also be prepared by high temperature and high pressure method to realize n-type diamond semiconductor material. (Reference: [Liu XB, Chen X, Singh DJ, et al. Boron–oxygen complex yields n-type surface layer in semiconducting diamond[J]. Proceedings of the National Academy of Sciences, 2019, 116(16):7703-7711.]) Based on the above existing research results, n-type diamond semiconductors have not yet been effectively applied in electronic devices, particularly high-power devices. The difficulty of doping n-type diamond semiconductors has severely hampered the development and practical application of high-performance diamond-based electronic devices. Limited by the shortcomings of n-type diamond preparation processes, high-performance semiconductor structures are not currently widely used. Reducing the difficulty of doping n-type diamond and further improving its electron mobility and concentration to form high-performance semiconductor structures are technical issues that require further exploration. Summary of the Invention

[0005] In view of this, the present application provides a semiconductor structure and a method for preparing the same, aiming to provide a method for preparing N-type diamond with high electron mobility and electron concentration, so as to provide a PN junction with high performance.

[0006] In a first aspect, the present application provides a method for preparing a semiconductor structure, comprising: providing a substrate; Prepare a first semiconductor layer on the surface of the substrate, wherein the first semiconductor layer is a diamond layer having a first doping type; Preparation of a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other is P-type doping.

[0007] Optionally, the step of preparing a diamond layer with an N-type doping type is as follows: Turning on the microwave power source, and under the condition of a growth temperature of 750-900 DEG C and a growth pressure of 160-210 mbar, introducing a carbon source, a boron source, a nitrogen source and a growth gas to epitaxially obtain a boron-nitrogen co-doped N-type diamond layer.

[0008] Optionally, the microwave power of the microwave power source is 3.7-6.0 kW.

[0009] Optionally, the boron-nitrogen ratio is 1:1-1:4.

[0010] Optionally, the carbon source concentration is 4-8%.

[0011] Optionally, the step of preparing a diamond layer with a P-type doping is as follows: Using the same microwave power, the same growth pressure, the same growth temperature, the same flow rate of the carbon source, the same flow rate of the boron source and the same flow rate of the growth gas as those for the N-type diamond layer, a boron-doped P-type diamond layer is epitaxially obtained in the growth cavity.

[0012] Optionally, the method further comprises: Before the preparation of the first semiconductor layer, the substrate is pretreated to eliminate defects and contaminants on the surface of the substrate.

[0013] Optionally, before the preparation of the first semiconductor layer, a buffer layer is prepared on the surface of the substrate.

[0014] Optionally, before the preparation of the first semiconductor layer, the step of preparing a buffer layer on the surface of the substrate comprises: Turning on the microwave power source, and under the condition of a growth temperature of 750-900 DEG C and a growth pressure of 160-210 mbar, introducing a carbon source and a growth gas to epitaxially obtain an intrinsic diamond layer.

[0015] In a second aspect, the application provides a semiconductor structure prepared by the method according to any one of the above.

[0016] The technical scheme provided by the application has at least the following beneficial effects: A complete single crystal diamond-based PN junction is constructed. Since diamond has excellent properties such as super-wide band gap, high thermal conductivity and high breakdown field strength, and especially, a completely single crystal diamond has higher electron and hole mobility. Therefore, the PN junction composed of diamond can withstand greater voltage, produce smaller leakage current, and exhibit more excellent on and off performance. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 The flow chart of the preparation method of the semiconductor structure provided by an embodiment of the present application is shown.

[0019] Figure 2 The flow chart of the preparation method of the diode provided by an embodiment of the present application is shown.

[0020] Figure 3 The flow chart of the preparation method of the semiconductor structure provided by another embodiment of the present application is shown.

[0021] Figure 4 The flow chart of the preparation method of the diode provided by another embodiment of the present application is shown.

[0022] Figure 5 The structural schematic diagram of the semiconductor structure provided by an embodiment of the present application is shown.

[0023] Figure 6 The structural schematic diagram of the diode provided by an embodiment of the present application is shown.

[0024] Figure 7 The schematic diagram of the test results of the boron-nitrogen co-doped N-type diamond based on the MPCVD process provided by the present application is shown.

[0025] Figure 8 The formation energy comparison diagram of the boron-nitrogen co-doped and boron-oxygen co-doped N-type diamond structure provided by the present application is shown.

[0026] The reference signs are as follows: 11: substrate; 12: diamond buffer layer; 13: first semiconductor layer; 14: second semiconductor layer; 15: first electrode; 16: second electrode. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] Figure 1 This is a flow chart of a method for preparing a semiconductor structure according to an embodiment of the present application. Figure 1 ,include: S101. Provide a substrate.

[0029] In one example, the substrate is a diamond substrate.

[0030] Illustratively, the size of the substrate may be 7 mm×7 mm×0.25 mm, but the size range is not limited thereto.

[0031] S102 , preparing a first semiconductor layer on the surface of the substrate, where the first semiconductor layer is a diamond layer having a first doping type.

[0032] In one example, the first doping type is N-type doping, and step S102 includes: The microwave power supply is turned on, and a carbon source, a boron source, a nitrogen source and a growth gas are introduced under a growth temperature of 750°C to 900°C and a growth pressure of 160mbar to 210mbar to epitaxially obtain a boron-nitrogen co-doped N-type diamond layer.

[0033] For example, a microwave power supply is turned on, and a carbon source, a boron source, a nitrogen source and a growth gas are introduced under an environment of a growth temperature of 800° C. and a growth pressure of 180 mbar to obtain a boron-nitrogen co-doped N-type diamond layer by epitaxy.

[0034] In one example, the boron source is diborane.

[0035] In one example, the nitrogen source is nitrogen gas.

[0036] In one example, the microwave power of the microwave power supply is 3.7 kW to 6.0 kW.

[0037] Exemplarily, the microwave power of the microwave power supply is 5.0 kW.

[0038] In one example, the boron to nitrogen ratio is 1:1 to 1:4.

[0039] Exemplarily, the boron to nitrogen ratio is 1:1 to 1:2.

[0040] In one example, the carbon source concentration is 4% to 8%.

[0041] Exemplarily, the carbon source concentration is 6%.

[0042] In an example, the carbon source is methane.

[0043] In an example, the thickness of the boron-doped P-type diamond layer is 10-50 nm.

[0044] Exemplarily, the thickness of the boron-doped P-type diamond layer is 20 nm.

[0045] In another example, the first doping type is P-type doping, and the step S102 comprises: Turning on the microwave power source, and introducing the carbon source, the boron source and the growth gas under the environment of a growth temperature of 750-900°C and a growth pressure of 160-210 mbar to epitaxially obtain a boron-doped P-type diamond layer.

[0046] For example, turning on the microwave power source, and introducing the carbon source, the boron source and the growth gas under the environment of a growth temperature of 800°C and a growth pressure of 180 mbar to epitaxially obtain a boron-doped P-type diamond layer.

[0047] In an example, the microwave power of the microwave power source is 3.7-6.0 kW.

[0048] Exemplarily, the microwave power of the microwave power source is 5.0 kW.

[0049] In an example, the carbon source concentration is 4-8%.

[0050] Exemplarily, the carbon source concentration is 6%.

[0051] In an example, the carbon source is methane.

[0052] In an example, the thickness of the boron-doped P-type diamond layer is 10-50 nm.

[0053] Exemplarily, the thickness of the boron-doped P-type diamond layer is 20 nm.

[0054] S103, preparing a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other is P-type doping.

[0055] In an example, the second doping type is P-type doping, and the step S103 comprises: Turning on the microwave power source, and introducing the carbon source, the boron source and the growth gas under the environment of a growth temperature of 750-900°C and a growth pressure of 160-210 mbar to epitaxially obtain a boron-doped P-type diamond layer.

[0056] For example, the microwave power source is turned on, and carbon source, boron source and growth gas are introduced under the condition of a growth temperature of 800 DEG C and a growth pressure of 180 mbar, to epitaxially obtain a boron-doped P-type diamond layer.

[0057] In an example, the microwave power of the microwave power source is 3.7 kW-6.0 kW.

[0058] For example, the microwave power of the microwave power source is 5.0 kW.

[0059] In an example, the concentration of the carbon source is 4%-8%.

[0060] For example, the concentration of the carbon source is 6%.

[0061] In an example, the carbon source is methane.

[0062] In an example, the thickness of the boron-doped P-type diamond layer is 10-50 nm.

[0063] For example, the thickness of the boron-doped P-type diamond layer is 20 nm.

[0064] In another example, the second doping type is N-type doping, and the step S103 comprises: The microwave power source is turned on, and carbon source, boron source, nitrogen source and growth gas are introduced under the condition of a growth temperature of 750 DEG C-900 DEG C and a growth pressure of 160 mbar-210 mbar, to epitaxially obtain a boron-nitrogen co-doped N-type diamond layer.

[0065] For example, the microwave power source is turned on, and carbon source, boron source, nitrogen source and growth gas are introduced under the condition of a growth temperature of 800 DEG C and a growth pressure of 180 mbar, to epitaxially obtain a boron-nitrogen co-doped N-type diamond layer.

[0066] In an example, the boron source is diborane.

[0067] In an example, the nitrogen source is nitrogen.

[0068] In an example, the microwave power of the microwave power source is 3.7 kW-6.0 kW.

[0069] For example, the microwave power of the microwave power source is 5.0 kW.

[0070] In an example, the boron-nitrogen ratio is 1:1-1:4.

[0071] For example, the boron-nitrogen ratio is 1:1-1:2.

[0072] In an example, the concentration of the carbon source is 4%-8%.

[0073] For example, the concentration of the carbon source is 6%.

[0074] In an example, the carbon source is methane.

[0075] In an example, the thickness of the boron-nitrogen co-doped N-type diamond layer is 10-50 nm.

[0076] In an example, the thickness of the boron-nitrogen co-doped N-type diamond layer is 20 nm.

[0077] It should be noted that the above preparation method is applicable to the diode of the normal structure, the flip-chip structure, and the vertical structure.

[0078] Figure 2 A flow chart of a preparation method of a diode according to an embodiment of the present application is provided. Referring to FIG. 1, Figure 2 , the preparation method comprises the following steps. S201, providing a substrate.

[0079] Referring to step S101.

[0080] S202, preparing a first semiconductor layer on the surface of the substrate, the first semiconductor layer being a diamond layer with a first doping type.

[0081] Referring to step S102.

[0082] S203, preparing a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type being N-type doping, and the other being P-type doping.

[0083] Referring to step S103.

[0084] S204, performing a patterning process on the second semiconductor layer to expose the first semiconductor layer.

[0085] Step S204 is an alternative step. When a flip-chip structure light emitting diode is prepared, the first semiconductor layer is a P-type diamond layer, and the second semiconductor layer is an N-type diamond layer. In this case, the patterning process is directly performed on the second semiconductor layer.

[0086] When a flip-chip structure light emitting diode is prepared, the first semiconductor layer is an N-type diamond layer, and the second semiconductor layer is a P-type diamond layer. Through a bonding process, a carrier substrate is bonded to the surface of the second semiconductor layer, and the original substrate is removed. Subsequently, the patterning process is performed on the first semiconductor layer to expose the second semiconductor layer.

[0087] In an example, the patterning process can be achieved through a photolithography process and an etching process.

[0088] S205, manufacturing a first electrode and a second electrode, the first electrode being electrically connected with the first semiconductor layer, and the second electrode being electrically connected with the second semiconductor layer.

[0089] In an example, the first electrode and the second electrode can be formed by sputtering on the surfaces of the first semiconductor layer and the second semiconductor layer.

[0090] In an example, the first electrode is an N electrode (connected with the N-type diamond layer) and includes a Ti layer, a Pt layer and an Au layer.

[0091] In an example, the second electrode is a P electrode (connected with the P-type diamond) and includes a Ti layer and an Au layer.

[0092] In another example, the first electrode is a P electrode (connected with the N-type diamond layer) and includes a Ti layer and an Au layer.

[0093] In another example, the second electrode is an N electrode (connected with the P-type diamond) and includes a Ti layer, a Pt layer and an Au layer.

[0094] Of course, it should be noted that, before manufacturing the electrodes, a passivation layer can also be manufactured on the surfaces of the semiconductor layers for insulation and isolation, which is not limited in the present application.

[0095] Figure 3 A flow chart of a method for manufacturing a semiconductor structure is provided for another embodiment of the present application. Referring to FIG. 6, Figure 3 , the method comprises the following steps. S301, providing a substrate.

[0096] Referring to step S101.

[0097] S302, pre-treating the substrate.

[0098] In an example, step S302 comprises the following steps. Step 1, polishing the substrate.

[0099] In this example, the substrate is polished on both sides to ensure that the surface roughness is between 5-10 nm.

[0100] Step 2, cleaning the substrate.

[0101] In an example, step 2 comprises the following steps. In this example, the surface of the diamond substrate is treated by placing the diamond substrate in a sulfuric acid solution and heating for 30 minutes. Then, the diamond substrate is sequentially cleaned in acetone, anhydrous ethanol and deionized water for 15 minutes each. Finally, the diamond substrate is dried with nitrogen.

[0102] Of course, the cleaning method of the diamond substrate is not limited to the above method, and the cleaning method of the diamond substrate is not limited in the present application.

[0103] S303, preparing a buffer layer on the surface of the substrate.

[0104] In an example, step S303 comprises: The diamond buffer layer is epitaxially grown by an MPCVD (microwave chemical vapor deposition) process, and the epitaxial process conditions are as follows: temperature 750-900°C, microwave power 3.7-6.0 kW, pressure 160-210 mbar, hydrogen flow rate 200-550 sccm, and methane concentration 4-6%.

[0105] In an example, the thickness of the diamond buffer layer is 20-30 nm.

[0106] Illustratively, the thickness of the diamond buffer layer is 25 nm.

[0107] S304, preparing a first semiconductor layer on the surface of the substrate, the first semiconductor layer being a diamond layer with a first doping type.

[0108] See step S102.

[0109] S305, preparing a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other is P-type doping.

[0110] See step S103.

[0111] Figure 4 A flow chart of a preparation method of a diode is provided for another embodiment of the present application. See Figure 4 , comprising: S401, providing a substrate.

[0112] See step S101.

[0113] S402, pretreating the substrate.

[0114] See step S302.

[0115] S403, preparing a buffer layer on the surface of the substrate.

[0116] See step S303.

[0117] S404, preparing a first semiconductor layer on the surface of the substrate, the first semiconductor layer being a diamond layer with a first doping type.

[0118] See step S102.

[0119] S405, preparing a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other is P-type doping.

[0120] See step S103.

[0121] S406, performing a patterning process on the second semiconductor layer to expose the first semiconductor layer.

[0122] See step S204.

[0123] S407, manufacturing a first electrode and a second electrode, the first electrode being electrically connected to the first semiconductor layer, and the second electrode being electrically connected to the second semiconductor layer.

[0124] See step S205.

[0125] Figure 5 A structure schematic diagram of a semiconductor structure provided by an embodiment of the present application is shown in FIG. 11. Figure 5 The semiconductor structure includes, in sequence, a substrate 11, a diamond buffer layer 12, a first semiconductor layer 13, and a second semiconductor layer 14.

[0126] Figure 6 A structure schematic diagram of a diode provided by an embodiment of the present application is shown in FIG. 12. Figure 6 The diode includes, in sequence, a substrate 11, a diamond buffer layer 12, a first semiconductor layer 13, and a second semiconductor layer 14, and a first electrode 15 connected to the first semiconductor layer and a second electrode 16 connected to the second semiconductor layer.

[0127] Figure 7 A test result schematic diagram of boron-nitrogen co-doped N-type diamond based on an MPCVD process provided by the present application is shown in FIG. 13. Figure 7 , Figure 7 The electron mobility and electron concentration of N-type diamond prepared by boron-nitrogen co-doping and boron-oxygen co-doping are compared.

[0128] The electron mobility and electron concentration of the boron-nitrogen co-doped N-type diamond are much higher than those of the boron-oxygen co-doped N-type diamond.

[0129] Figure 8 A formation energy comparison diagram of boron-nitrogen co-doped and boron-oxygen co-doped N-type diamond structures provided by the present application is shown in FIG. 14, further comparing the formation energy of the boron-nitrogen co-doped and boron-oxygen co-doped N-type diamond structures.

[0130] It should be noted that the boron-nitrogen co-doped N-type diamond manufactured by the MPCVD process has the following beneficial effects: 1、Boron and nitrogen can form stable boron-nitrogen covalent bond, and the doping formation energy is significantly lower than single phosphorus doping or boron-oxygen co-doping. On the one hand, the boron-nitrogen covalent bond reduces the total energy of the system for charge compensation, on the other hand, the spatial matching of boron-nitrogen covalent bond in the lattice is better, resulting in the minimum lattice distortion, so that the difficulty of making high electrical performance N-type doped diamond by boron-nitrogen co-doping is lower. By increasing the doping concentration to improve the electrical performance, as the doping concentration rises, the electrical performance will gradually reach the upper limit without damaging the lattice. Due to the better spatial matching of boron-nitrogen covalent bond in the diamond lattice, the upper limit of the electrical performance of the N-type diamond prepared by boron-nitrogen co-doping is higher, that is, the electron concentration and electron mobility are higher.

[0131] 2、Boron provides holes, nitrogen provides electrons, both form electrically neutral counter-doping, which helps to adjust the local electric potential and suppress self-compensation behavior. Especially in diamond, boron-nitrogen co-doping can make the donor level shallower, improve ionization efficiency, and enhance n-type conductivity. For traditional phosphorus-doped N-type diamond, phosphorus is a typical N-type donor, but due to its deep energy level (about 0.6 eV) and large self-compensation effect (such as forming P-V pairs), the activation efficiency is low and the carrier concentration is limited. For example, compared with boron-oxygen co-doping in the prior art, boron and oxygen doping can form B-O pairs, which can theoretically adjust the carrier concentration, but due to the possibility of inducing deep level traps by oxygen, the overall ionization energy is not ideal, and the charge compensation behavior is unstable.

[0132] 3、Boron-nitrogen co-doping can introduce shallow donor levels without significantly reducing the band gap, optimize the conduction band edge, and improve the overall electronic structure. The energy level introduced by traditional phosphorus doping is usually deep, which is not conducive to the generation of effective carriers, and may introduce impurity states to affect device performance. Boron-oxygen co-doping may introduce neutral defect states in the band gap, which brings electron recombination centers and is not conducive to the improvement of conductivity.

[0133] 4、Boron and nitrogen co-doping can form B-N bonds, which have bond length and bond energy closer to C-C bonds in diamond crystal structure, and the disturbance to the crystal structure after doping is minimal, with the best stability and easy industrial control. Compared with phosphorus doping, the atomic size difference of phosphorus is large, which easily causes local structure relaxation or even forms amorphous regions, and has poor stability. Compared with boron-oxygen co-doping, oxygen doping has strong chemical activity, which is easy to form non-ideal bonding or oxygen vacancies, reducing the structural integrity.

[0134] The MPCVD process for preparing n-type boron-nitrogen co-doped diamond films presents numerous challenges. Boron (B) and nitrogen (N) are introduced into the diamond lattice as co-doping elements, achieving n-type conductivity through the mutual compensation of boron's deep donor energy levels with nitrogen's deep acceptor energy levels. However, boron and nitrogen have extremely low solubility in diamond, and they tend to form numerous BN composite defects, rather than being effectively activated as single dopant atoms. The presence of these composite defects significantly reduces the efficiency of carrier (electron) generation, leading to insufficient n-type conductivity. Furthermore, boron (B) and nitrogen (N) have different efficiencies when incorporated into diamond, making precise control of the boron and nitrogen doping ratio a key challenge in achieving effective n-type doping. Furthermore, factors such as the uniform distribution of the impurity elements and the stability of the reaction environment must also be considered, all of which affect the film's crystal quality, conductivity, and mechanical properties. Furthermore, equipment optimization and annealing processes also influence the film's final properties. Therefore, ensuring precise control of each step is crucial for successfully preparing high-quality doped diamond films.

[0135] In order to solve the problem that n-type semiconductor diamond doping is difficult in the prior art and cannot be effectively applied to high-performance electronic devices, especially high-power devices, the present invention proposes a boron-nitrogen co-doped high-performance n-type single crystal diamond film based on MPCVD technology and its preparation method. The core of the invention is to achieve efficient co-doping of boron and nitrogen by precisely controlling the process parameters during the growth process. In the MPCVD preparation process, high-purity As a carbon source, As carrier gas, and As boron source and nitrogen source respectively, the gas ratio is controlled as follows: : =4~8%, ensuring that the boron-nitrogen concentration ratio is between 1:1 and 1:4 to optimize the compensation effect between p-type holes (boron replaces carbon atoms, donor energy level 0.37eV) and n-type electrons (nitrogen replaces carbon atoms, donor energy level 1.7eV). The growth temperature is controlled in stages. By controlling the microwave power and chamber pressure, the growth temperature is guaranteed to be 750~900℃ to enter stable growth. The temperature gradient is controlled within ±10°C to avoid nitrogen desorption or boron diffusion. The microwave power is set to 3.7~6.0kW. The initial low power reduces surface etching, and the power is increased later to improve 、 、 Dissociation efficiency ( The decomposition rate increased from 20% to 50%). The reaction chamber pressure was 160-210 mbar, and the uniformity of the plasma ball was adjusted to ensure the flatness of the diamond growth surface. During the growth process, the spectral intensity of boron and nitrogen was monitored by in-situ optical emission spectroscopy (OES), and the flow rate was adjusted in real time. These control measures work together to efficiently incorporate boron and nitrogen into the crystal lattice, reducing The composite defects and lattice distortion finally form N-type diamond thin film with electron mobility of 10-1500 , carrier concentration ~ The application significantly improves the application potential of the N-type diamond thin film in high-power devices. Compared with the prior art, the application overcomes the problems of low doping efficiency and poor uniformity by specific gas ratio, temperature segmentation, power dynamic adjustment, pressure bias design and real-time monitoring, and provides a feasible path for the research and development of n-type diamond-based electronic devices.

[0136] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of fabricating a semiconductor structure, characterized by, The method comprises the following steps: providing a substrate; preparing a first semiconductor layer on the surface of the substrate, the first semiconductor layer being a diamond layer with a first doping type; preparing a second semiconductor layer on the surface of the first semiconductor layer, the second semiconductor layer being a diamond layer with a second doping type; one of the first doping type and the second doping type is N-type doping, and the other is P-type doping.

2. The method of claim 1, wherein the semiconductor structure is prepared by a method comprising: The steps of preparing the diamond layer with the N-type doping type are as follows: turning on a microwave power source, introducing a carbon source, a boron source, a nitrogen source and a growth gas in an environment with a growth temperature of 750-900 ℃ and a growth pressure of 160-210 mbar, and epitaxially obtaining a boron-nitrogen co-doped N-type diamond layer.

3. The method of claim 2, wherein the semiconductor structure is prepared by a method comprising: The microwave power of the microwave power source is 3.7-6.0 kW.

4. The method of claim 2, wherein the semiconductor structure is prepared by a method comprising: The boron-nitrogen ratio is 1:1-1:

4.

5. The method of claim 2, wherein the semiconductor structure is prepared by a method comprising: The carbon source concentration is 4-8%.

6. The method of producing a semiconductor structure according to any one of claims 1 to 5, wherein The steps of preparing the diamond with the P-type doping are as follows: using the same microwave power, the same growth pressure, the same growth temperature, the same flow rate of the carbon source, the same flow rate of the boron source and the same flow rate of the growth gas as those for the N-type diamond layer, and epitaxially obtaining a boron-doped P-type diamond layer in a growth cavity.

7. The method of producing a semiconductor structure according to any one of claims 1 to 5, wherein The method further comprises: before preparing the first semiconductor layer, pretreating the substrate to eliminate defects and contaminants on the surface of the substrate.

8. The method of producing a semiconductor structure according to any one of claims 1 to 5, wherein before preparing the first semiconductor layer, preparing a buffer layer on the surface of the substrate.

9. The method of claim 8, wherein the semiconductor structure is prepared by a method comprising: The step of preparing the buffer layer on the surface of the substrate before preparing the first semiconductor layer comprises: turning on a microwave power source, introducing a carbon source and a growth gas in an environment with a growth temperature of 750-900 ℃ and a growth pressure of 160-210 mbar, and epitaxially obtaining an intrinsic diamond layer.

10. A semiconductor structure, characterized by The method is prepared by using the method according to any one of claims 1-9.

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