Alscn thin film grown by atomic layer deposition method and preparation method thereof

Abstract

The application provides an atomic layer deposition method for growing an AlScN film and a preparation method thereof, and comprises the following steps: growing a high-quality AlScN film by using an atomic layer deposition (ALD) method; the application can reduce defects in the film, avoids the non-uniformity and defects of the interface, and significantly improves the interface quality between the AlScN film and the substrate, which is helpful to improve the structural integrity, three-dimensional uniformity, interface coupling and interface state of the film compared with a traditional growth method. Optimizing the interface quality is crucial for improving the performance of the film.

Description

Technical Field

[0001] This invention relates to the field of thin film growth technology, specifically to an atomic layer deposition method for growing AlScN thin films and its preparation method. Background Technology

[0002] AlScN (AlScandium Nitrogen) is a material with excellent physical and chemical properties, including high acoustic velocity, strong polarity, low temperature coefficient of frequency (TCF), and compatibility with CMOS processes. It has broad application prospects in optoelectronics, information storage, and biomedicine. The advantages of AlScN thin films mainly include high thermal stability, optical properties, high hardness and wear resistance, excellent electrical properties, high voltage strain resistance, and biocompatibility. The high thermal stability of AlScN thin films means they maintain excellent thermal stability at high temperatures, preserving their structural and performance stability, making them promising for high-temperature applications such as high-temperature electronic devices and welding materials. The optical properties of AlScN thin films also offer potential applications in optics. Due to its wide bandgap, it exhibits excellent optical transparency and refractive index control, making it promising for devices such as solar cells, optical coatings, and optical sensors. The high hardness and wear resistance of AlScN thin films allow them to resist scratches and abrasion. The excellent electrical properties of AlScN thin films further enhance their appeal. AlScN thin films possess high dielectric constant and low resistivity, making them widely used in radio frequency and microwave devices such as filters, resonators, and MEMS (Micro-Electro-Mechanical Systems) devices. The extremely high piezoelectric strain of AlScN thin films makes them ideal for manufacturing piezoelectric sensors and actuators; this strain property can be applied to oscillating resonators, acoustic filters, pressure sensors, and micro-speakers. Furthermore, AlScN thin films exhibit excellent biocompatibility, making them promising for biomedical applications such as medical devices, biosensors, and tissue engineering. Due to their stability and low toxicity, they can also be used in areas such as in vivo drug delivery. In summary, AlScN thin films possess these advantages and have broad application prospects in scientific research and engineering.

[0003] Currently, there are many methods for preparing AlScN thin films, such as molecular beam epitaxy, metal-organic chemical vapor deposition (MOCVD), and sputtering deposition. Molecular beam epitaxy has very strict requirements for growth conditions, such as temperature, pressure, and atmosphere. This results in high cost and difficulty in growing large-area uniform films, with poor step coverage. It is only suitable for depositing films on planar substrates. MOCVD requires a high-temperature environment for growing AlScN films, placing high demands on the thermal stability of equipment and materials. It also requires complex and strict temperature control; improper temperature management can easily lead to film degradation, thermal stress, and strain problems, making it difficult to accurately control the film thickness. During sputtering deposition, the high energy of the sputtered particles can cause deviations in the composition of the grown film from the target. Furthermore, this method has poor three-dimensional uniformity, easily forming defects such as clusters and pinholes, thus affecting the film quality. Therefore, these thin film preparation methods not only require high temperatures and have many defects, but also produce thin films with poor large-area uniformity. They cannot achieve the deposition of high-quality, three-dimensionally uniform thin films on substrates with high aspect ratios. Furthermore, the thickness control of the thin films is not precise, and the material properties cannot be well exhibited when fabricating devices.

[0004] Therefore, it is necessary to find a new method for preparing AlScN thin films that can grow high-quality films with precise and controllable thickness and achieve three-dimensional uniform growth. This is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an atomic layer deposition method for growing AlScN thin films and its preparation method, which solves the limitations of existing AlScN thin film growth methods, such as numerous defects, inaccurate thickness control, and poor three-dimensional uniformity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides an atomic layer deposition method for growing AlScN thin films and a method for preparing the same, comprising the following steps: growing AlScN thin films using the ALD method.

[0008] Preferably, AlScN thin films are grown using the ALD method, specifically:

[0009] Step 1: Place the clean substrate into the ALD reactor;

[0010] Step 2: Set the AlScN precursor temperature for vaporization, and set the temperature, pressure, gas flow rate, and pulse time of the ALD reactor.

[0011] Step 3: Based on step 2, an AlScN thin film is deposited and grown on the substrate.

[0012] Preferably, in step 1, the substrate is a silicon wafer or sapphire.

[0013] Preferably, in step 2, the AlScN precursor temperature is set to 100-150℃ for vaporization. The AlScN precursor includes aluminum precursor, scandium precursor, and nitrogen precursor, wherein the aluminum precursor is trimethylaluminum; the scandium precursor is Sc-Cp2 or Sc-Cp3; and the nitrogen precursor is nitrogen plasma, ammonia or ammonia plasma.

[0014] Preferably, in step 2, the temperature of the ALD reactor is set to 100-400℃, the pressure to 5-10 Torr, the gas flow rate to 100-300 sccm, and the pulse time to 50-500 ms. Preferably, in step 3, after depositing and growing the AlScN film on the substrate, an annealing treatment is performed to optimize the film properties and obtain an AlScN film with better crystallinity.

[0015] Preferably, the annealing process conditions are: annealing temperature of 500-1100℃ and annealing time of 30-120 minutes.

[0016] An AlScN thin film was prepared using the method described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This invention provides an atomic layer deposition (ALD) method for growing AlScN thin films and its preparation method. The ALD method allows for precise control of the film's crystal structure: AlScN films possess tunable lattice constants and crystal structures, which can be controlled by adjusting the Sc content and growth conditions, thereby enabling the regulation of film properties. This ability to control crystal structure provides broader possibilities for the application of AlScN films. Higher film quality: ALD is a layer-by-layer atomic deposition technique. During the growth of AlScN films, the composition and thickness of each layer can be precisely controlled through layer-by-layer reactions. This atomic-level control reduces the presence of impurities and the formation of defects, resulting in higher overall film quality compared to other techniques. High precision and high uniformity: ALD technology can precisely control the time and conditions of each layer's chemical reaction. During AlScN film growth, precursor molecules adsorb and react on the surface. The chemical bonds formed by the adsorbed molecules on the surface limit the occurrence of subsequent reactions. After each reaction, byproducts and excess precursors are eliminated, ensuring that only the correct amount of precursor participates. This self-limiting growth characteristic facilitates the achievement of highly uniform thin films and improves interface quality: ALD technology enables atomic-level growth control. During the growth of AlScN thin films using ALD, the precursor source reacts with the surface to generate a complete layer of chemical reaction products, and excess chemical precursor molecules are eliminated, thus ensuring the self-limiting formation of the film. This self-limiting characteristic allows for precise and controllable uniform film thickness, avoiding interface inhomogeneities and defects, and significantly improving the interface quality between the AlScN film and the substrate. Compared with traditional growth methods, this helps improve the structural integrity of the film, interface coupling, and the influence of interface states. Optimizing interface quality is crucial for improving film performance. Attached Figure Description

[0019] Figure 1 This is a flowchart related to the present invention. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] This invention utilizes ALD (Atomic Layer Deposition) technology to grow AlScN thin films. ALD technology is a thin film method that forms a film by alternately introducing a gaseous precursor into a reaction chamber and causing a gas-solidification chemical reaction on the substrate surface. During growth, the chemical reaction of the new atomic layer is directly related to the previous layer, ensuring that only one atomic layer is deposited per reaction. By setting the number of atomic layer deposition cycles, ALD can achieve atomically controlled film deposition. Furthermore, the formation of atomic layers during atomic layer deposition requires high-precision, high-sensitivity detection instruments and control systems. These devices ensure the accuracy and stability of film growth, resulting in a highly uniform surface morphology. This uniformity reduces the presence of surface defects and impurities, improving the quality and stability of the film. In summary, ALD technology solves the problems of uneven film quality and inaccurate film thickness often caused by traditional thin film growth methods, while also providing a new approach for the subsequent growth of AlScN thin films.

[0022] Example 1

[0023] like Figure 1 As shown in the figure, this embodiment provides an atomic layer deposition method for growing AlScN thin films and its preparation method, which includes the following steps:

[0024] Step 1: Place the cleaned substrate into the ALD reactor;

[0025] Step 2: Set the AlScN precursor temperature for vaporization;

[0026] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area to grow AlScN thin films in the reaction chamber;

[0027] Step 4: By controlling the pulse time, the precursor is alternately adsorbed and reacted in the deposition area;

[0028] Step 5: Repeat step 4 until the desired film thickness is achieved;

[0029] Step 6: Keep in the reaction chamber for 50-70 minutes to obtain a film with high uniformity and purity;

[0030] Step 7: After the reaction is complete, annealing is performed to optimize the film properties and obtain AlScN films with better crystal quality. The surface morphology of the film is then observed using a scanning electron microscope.

[0031] Furthermore, in step 1, the cleaned substrate is a silicon wafer or sapphire.

[0032] Furthermore, in step 2, the AlScN precursor temperature is set to 100-150℃, and the AlScN precursor includes an aluminum precursor, a scandium precursor, and a nitrogen precursor, wherein the aluminum precursor is trimethylaluminum; the scandium precursor is Sc-Cp2 or Sc-Cp3; and the nitrogen precursor is nitrogen plasma, ammonia, or ammonia plasma.

[0033] Furthermore, in step 3, the temperature of the deposition area is 100-400℃, the pressure is 5-10 Torr, and the gas flow rate is 100-300 sccm.

[0034] Furthermore, in step 4, the pulse duration is 50-500ms.

[0035] Furthermore, in step 5, the expected film thickness is 5-50 nm.

[0036] Furthermore, in step 7, the annealing process conditions are:

[0037] The annealing temperature was set to 500-1100℃, and the annealing time was 30-120 minutes. Annealing was initiated, and the annealing temperature was maintained while the film was slowly cooled to room temperature in the furnace. After annealing, the film was removed. Annealing helps the crystal structure in the film to rearrange and reorganize, thereby improving its crystallinity. This results in a better crystal structure and higher crystal quality. Furthermore, defects such as vacancies, grain boundaries, and grain defects may exist during film growth. Annealing can promote the rearrangement and recombination of these defects, and some defects may even disappear, thus reducing the defect density of the film. The surface morphology of the film was then observed using a scanning electron microscope.

[0038] Furthermore, the presence of Sc in the film can significantly improve its piezoelectric properties, and it also exhibits excellent weather resistance and mechanical strength.

[0039] The working principle of this embodiment:

[0040] Although ALD technology is mature, there are no precedents for its use in growing AlScN thin films. This is because there are technical challenges in using ALD technology to grow AlScN thin films, one of which is the lack of good scandium precursor sources. The reasons are as follows:

[0041] In actual ALD reaction processes, the vapor pressure of the scandium source must reach above 3 torr under normal circumstances in order to obtain a sufficient molar flow rate to complete the ALD reaction. However, the volatility of existing scandium precursors is very low, making it impossible to obtain a sufficient molar flow rate. At the same time, the deposition temperature of conventional ALD processes is between 100-400℃, and within this temperature range, the reactivity of general scandium precursors is not high.

[0042] Therefore, this invention utilizes Sc-Cp2 or Sc-Cp3 as a scandium precursor source for the following reasons:

[0043] Both Sc-Cp2 and Sc-Cp3 contain cyclopentadienyl groups in their molecular structures. Cyclopentadienyl groups are highly volatile hydrocarbons with relatively small molecular structures and weak intermolecular forces. This allows Sc-Cp2 and Sc-Cp3 molecules to evaporate and transport to the reaction surface relatively easily. Furthermore, Sc-Cp2 and Sc-Cp3 also have high thermal decomposition temperatures and are relatively stable, decomposing readily at suitable temperatures without significant degradation.

[0044] Meanwhile, at high temperatures, the chemical bonds of Sc-Cp2 and Sc-Cp3 break down, releasing scandium ions. These scandium ions have high energy at temperatures around 400°C, making them more likely to participate in chemical reactions. Furthermore, within this temperature range, the reaction rate increases with increasing temperature, thus enhancing the reactivity of scandium.

[0045] In addition, Sc-Cp2 and Sc-Cp3 have good volatility and solubility, and can be evaporated and transported into the reaction chamber more quickly and stably, thereby improving the reaction yield. Furthermore, the reaction rate of Sc-Cp2 and Sc-Cp3 is relatively slow, and the amount of reaction in each layer is easy to control, which helps to achieve fine film growth.

[0046] The second challenge lies in the fact that the experiment of growing AlScN thin films using ALD is particularly sensitive to gaseous impurities, which directly affect the final film growth results. For example, gas purification faces problems such as moisture, organic residues, oxygen content, and other impurities.

[0047] The third challenge lies in optimizing the reaction conditions.

[0048] The reactivity of Sc-Cp2 or Sc-Cp3 is influenced by various factors, including the selection of ligands attached to the precursor, steric hindrance, the number of functional groups, and the distance between functional groups. Therefore, precise control of parameters such as gas flow rate, pressure, and reactor chamber temperature is crucial to ensuring the complex reaction mechanism of the deposition process and thus growing the desired material and film. However, precise control of parameters such as gas flow rate, pressure, and reactor chamber temperature is particularly difficult, and poorly controlled reaction conditions can significantly impact the thickness, uniformity, and quality of the film.

[0049] Based on the physical and chemical properties of the precursor source, this invention designs a reasonable temperature range of 100-400℃, a pressure of 5-10 Torr, and a gas flow rate of 100-300 sccm. Within this range, the thin film growth process can be ensured to proceed smoothly. Furthermore, by changing the type of precursor source, the required thickness of the grown thin film, and the pulse time, the parameters can be precisely determined to specific values.

[0050] Example 2

[0051] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0052] Step 1: Perform surface treatment on the silicon wafer substrate to remove surface contaminants and oxides.

[0053] In this embodiment, cleaning is performed using organic solvents (ethanol or acetone). For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated silicon wafer surface should be clean and free of any visible impurities.

[0054] Step 2: Place a clean silicon wafer as a substrate into the ALD reactor and set the AlScN precursor temperature to 100°C for vaporization. The precursor consists of trimethylaluminum, Sc-Cp2, and ammonia.

[0055] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 300℃, a pressure of 10 Torr and a gas flow rate of 200 sccm.

[0056] Step 4: Control the pulse time to 50ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 5nm is achieved, and keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0057] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystal quality. The annealing temperature is 500℃ and the annealing time is 120 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0058] Example 3

[0059] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0060] Step 1: Perform surface treatment on the silicon wafer substrate to remove surface contaminants and oxides. This is typically done by cleaning with organic solvents such as ethanol or acetone. For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated silicon wafer surface should be clean and free of any visible impurities.

[0061] Step 2: Place a clean silicon wafer as a substrate into the ALD reactor and set the AlScN precursor temperature to 100°C for vaporization. The precursor consists of trimethylaluminum, Sc-Cp3, and nitrogen plasma.

[0062] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 300℃, a pressure of 10 Torr and a gas flow rate of 200 sccm.

[0063] Step 4: Control the pulse time to 50ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 5nm is achieved, and keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0064] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystallinity. The annealing temperature is 800℃ and the annealing time is 90 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0065] Example 4

[0066] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0067] Step 1: Perform surface treatment on the silicon wafer substrate to remove surface contaminants and oxides. This is typically done by cleaning with organic solvents such as ethanol or acetone. For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated silicon wafer surface should be clean and free of any visible impurities.

[0068] Step 2: Place a clean silicon wafer as a substrate into the ALD reactor and set the AlScN precursor temperature to 100°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp2, or ammonia plasma.

[0069] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 400℃, a pressure of 7 Torr and a gas flow rate of 200 sccm.

[0070] Step 4: Control the pulse time to 200ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 20nm is achieved. Then, keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0071] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystallinity. The annealing temperature is 800℃ and the annealing time is 90 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0072] Example 5

[0073] This embodiment is a preferred embodiment based on Embodiment 1, wherein the substrate is sapphire, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0074] Step 1: Perform surface treatment on the sapphire substrate to remove surface contaminants and oxides. This is typically done by cleaning with organic solvents such as ethanol or acetone. For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated sapphire surface should be clean and free of any visible impurities.

[0075] Step 2: Place the cleaned sapphire substrate into the ALD reactor and set the AlScN precursor temperature to 120°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp3, and ammonia.

[0076] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 400℃, a pressure of 7 Torr and a gas flow rate of 200 sccm.

[0077] Step 4: Control the pulse time to 200ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 20nm is achieved. Then, keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0078] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystallinity. The annealing temperature is 800℃ and the annealing time is 90 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0079] Example 6

[0080] This embodiment is a preferred embodiment based on Embodiment 1, wherein the substrate is sapphire, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0081] Step 1: Perform surface treatment on the sapphire substrate to remove surface contaminants and oxides. This is typically done by cleaning with organic solvents such as ethanol or acetone. For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated sapphire surface should be clean and free of any visible impurities.

[0082] Step 2: Place the cleaned sapphire substrate into the ALD reactor and set the AlScN precursor temperature to 120°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp2, or nitrogen plasma.

[0083] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 200℃, a pressure of 10 Torr and a gas flow rate of 200 sccm.

[0084] Step 4: Control the pulse time to 400ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 40nm is achieved. Then, keep it in the reaction chamber for 70 minutes to obtain a film with high uniformity and purity.

[0085] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystallinity. The annealing temperature is 800℃ and the annealing time is 90 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0086] Example 7

[0087] This embodiment is a preferred embodiment based on Embodiment 1, wherein the substrate is sapphire, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0088] Step 1: Perform surface treatment on the sapphire substrate to remove surface contaminants and oxides. This is typically done by cleaning with organic solvents such as ethanol or acetone. For solvent cleaning, it is generally recommended to perform 2-3 cleaning cycles, which can be adjusted according to experimental needs. Each cleaning cycle should last at least 3-5 minutes. The treated sapphire surface should be clean and free of any visible impurities.

[0089] Step 2: Place the cleaned sapphire substrate into the ALD reactor and set the AlScN precursor temperature to 120°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp3, or ammonia plasma.

[0090] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 200℃, a pressure of 10 Torr and a gas flow rate of 300 sccm.

[0091] Step 4: Control the pulse time to 100ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 10nm is achieved. Then, keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0092] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystallinity. The annealing temperature is 800℃ and the annealing time is 90 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0093] Example 8

[0094] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0095] Step 1 involves surface treatment of the silicon substrate to remove surface contaminants and oxides. This is typically accomplished using steps such as acid pickling. Acid cleaning: Pickling with a diluted acid solution (such as a mixture of HCl and HNO3) helps remove inorganic contaminants, metal oxides, and oxide films from the surface. Acid oxidation: Oxidation of the silicon substrate in concentrated nitric acid using the Mars-Maessen method forms a thin silicon dioxide layer, which is then removed by heat treatment or HF dissolution to clean the substrate surface.

[0096] Step 2: Place the clean silicon wafer as a substrate into the atomic layer deposition (ALD) reactor, and set the AlScN precursor temperature to 120°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp2, and ammonia.

[0097] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with the temperature at 100℃, the pressure at 10 Torr and the gas flow rate at 300 sccm.

[0098] Step 4: Control the pulse time to 50ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 10nm is achieved, and keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0099] Step 5: After the reaction is complete, annealing is performed to optimize the film properties and obtain AlScN films with better crystallinity. The annealing temperature is 1100℃ and the annealing time is 120 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0100] Example 9

[0101] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0102] Step 1 involves surface treatment of the silicon substrate to remove surface contaminants and oxides. This is typically accomplished using steps such as acid pickling. Acid cleaning: Pickling with a diluted acid solution (such as a mixture of HCl and HNO3) helps remove inorganic contaminants, metal oxides, and oxide films from the surface. Acid oxidation: Oxidation of the silicon substrate in concentrated nitric acid using the Mars-Maessen method forms a thin silicon dioxide layer, which is then removed by heat treatment or HF dissolution to clean the substrate surface.

[0103] Step 2: Place a clean silicon wafer as a substrate into an atomic layer deposition (ALD) reactor, and set the AlScN precursor temperature to 150°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp3, or nitrogen plasma.

[0104] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with the temperature at 100℃, the pressure at 10 Torr and the gas flow rate at 300 sccm.

[0105] Step 4: Control the pulse time to 500ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 50nm is achieved. Then, keep it in the reaction chamber for 70 minutes to obtain a film with high uniformity and purity.

[0106] Step 5: After the reaction is complete, annealing is performed to optimize the film properties and obtain AlScN films with better crystallinity. The annealing temperature is 1100℃ and the annealing time is 120 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0107] Example 10

[0108] This embodiment is a preferred embodiment based on Embodiment 1, wherein a silicon wafer is used as the substrate, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0109] Step 1 involves surface treatment of the silicon substrate to remove surface contaminants and oxides. This is typically accomplished using steps such as acid pickling. Acid cleaning: Pickling with a diluted acid solution (such as a mixture of HCl and HNO3) helps remove inorganic contaminants, metal oxides, and oxide films from the surface. Acid oxidation: Oxidation of the silicon substrate in concentrated nitric acid using the Mars-Maessen method forms a thin silicon dioxide layer, which is then removed by heat treatment or HF dissolution to clean the substrate surface.

[0110] Step 2: Place the clean silicon wafer as a substrate into the atomic layer deposition (ALD) reactor, and set the AlScN precursor temperature to 150°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp2, or ammonia plasma.

[0111] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 400℃, a pressure of 5 Torr and a gas flow rate of 300 sccm.

[0112] Step 4: Control the pulse time to 300ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 30nm is achieved. Then, keep it in the reaction chamber for 60 minutes to obtain a film with high uniformity and purity.

[0113] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystal quality. The annealing temperature is 500℃ and the annealing time is 30 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0114] Example 11

[0115] This embodiment is a preferred embodiment based on Embodiment 1, wherein a sapphire substrate is used, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0116] Step 1 involves surface treatment of the sapphire substrate to remove surface contaminants and oxides. This is typically accomplished through steps such as acid pickling. Immersing the sapphire substrate in an acidic solution, such as dilute sulfuric acid or hydrochloric acid, helps remove surface contaminants and oxide layers. Care should be taken to select an appropriate concentration and cleaning time to avoid damaging the sapphire surface.

[0117] Step 2: Place the cleaned sapphire as a substrate into the ALD reactor and set the AlScN precursor temperature to 150°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp3, and ammonia.

[0118] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 400℃, a pressure of 5 Torr and a gas flow rate of 100 sccm.

[0119] Step 4: Control the pulse time to 100ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 10nm is achieved. Then, keep it in the reaction chamber for 60 minutes to obtain a film with high uniformity and purity.

[0120] Step 5: After the reaction is complete, annealing is performed to optimize the film properties and obtain AlScN films with better crystallinity. The annealing temperature is 1100℃ and the annealing time is 120 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0121] Example 12

[0122] This embodiment is a preferred embodiment based on Embodiment 1, wherein a sapphire substrate is used, and the method for growing AlScN thin films by atomic layer deposition includes the following steps:

[0123] Step 1 involves surface treatment of the sapphire substrate to remove surface contaminants and oxides. This is typically accomplished through steps such as acid pickling. Immersing the sapphire substrate in an acidic solution, such as dilute sulfuric acid or hydrochloric acid, helps remove surface contaminants and oxide layers. Care should be taken to select an appropriate concentration and cleaning time to avoid damaging the sapphire surface.

[0124] Step 2: Place the cleaned sapphire as a substrate into the ALD reactor and set the AlScN precursor temperature to 150°C for vaporization. The precursor can be trimethylaluminum, Sc-Cp2, or ammonia plasma.

[0125] Step 3: Set appropriate temperature, pressure and gas flow rate in the deposition area, with a temperature of 400℃, a pressure of 5 Torr and a gas flow rate of 100 sccm.

[0126] Step 4: Control the pulse time to 50ms to allow the precursor to alternately adsorb and react in the deposition area until the expected film thickness of 5nm is achieved, and keep it in the reaction chamber for 50 minutes to obtain a film with high uniformity and purity.

[0127] Step 5: After the reaction is complete, annealing is performed to optimize the film performance and obtain AlScN films with better crystal quality. The annealing temperature is 500℃ and the annealing time is 30 minutes. The surface morphology of the film is observed using a scanning electron microscope.

[0128] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing AlScN thin films by atomic layer deposition, characterized in that, The process includes the following steps: growing AlScN thin films using the ALD method; specifically, growing AlScN thin films using the ALD method involves: Step 1: Place the clean substrate into the ALD reactor; Step 2: Set the AlScN precursor temperature for vaporization, and set the temperature, pressure, gas flow rate, and pulse time of the ALD reactor. Step 3: Based on step 2, an AlScN thin film is deposited and grown on the substrate; In step 2, the AlScN precursor temperature is set to 100-150℃ for vaporization; In step 2, the AlScN precursor includes an aluminum precursor, a scandium precursor, and a nitrogen precursor, wherein the aluminum precursor is trimethylaluminum; the scandium precursor is Sc-Cp2 or Sc-Cp3; and the nitrogen precursor is nitrogen plasma, ammonia, or ammonia plasma. In step 3, after depositing and growing an AlScN film on the substrate, an annealing process is performed to optimize the film performance and obtain an AlScN film with better crystal quality. The annealing process conditions are: annealing temperature of 500℃-1100℃, annealing time of 30-120 minutes; In step 2, the temperature of the ALD reactor is set to 100-400℃, the pressure to 5-10 Torr, the gas flow rate to 100-300 sccm, and the pulse time to 50-500 ms.

2. The method for preparing AlScN thin films by atomic layer deposition according to claim 1, characterized in that, In step 1, the substrate is a silicon wafer or sapphire.

3. An AlScN thin film, characterized in that, It is prepared using the preparation method described in claim 1 or 2.

Images