Aluminum nitride thin film and method for manufacturing the same

Abstract

This invention discloses an aluminum nitride thin film and its preparation method. The preparation method includes the following steps: taking an aluminum source and washing it for later use; placing the washed aluminum source in a radio frequency plasma system and pretreating it with ammonium salt plasma; then further treating the aluminum source with nitrogen plasma; after treatment, introducing an inert gas and cooling to room temperature to obtain the aluminum nitride thin film. The aluminum nitride thin film prepared by this method has the advantages of simple preparation method and high preparation efficiency, and can effectively solve the problems of high equipment requirements, high requirements for preparation parameters, and complex preparation processes in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of aluminum nitride thin film preparation technology, specifically relating to an aluminum nitride thin film and its preparation method. Background Technology

[0002] As a typical representative of group III-V nitride semiconductor materials, aluminum nitride (AlN) boasts excellent physicochemical properties, powerful functionality, and wide applications. With a bandgap width of 6.2 eV, AlN plays a crucial role in optoelectronic devices, enabling the detection of ultraviolet, deep ultraviolet, and vacuum ultraviolet light. Due to its thermal conductivity and electrical insulation properties, similar to silicon (Si), AlN can replace traditional highly toxic and expensive beryllium oxide (BeO) heat sinks in integrated circuits and high-power devices. Furthermore, AlN exhibits a high surface acoustic velocity (SAV) of 5600–6000 m / s, along with low transit loss, a large electromechanical coupling coefficient, and good high-temperature stability, making it a popular choice for surface acoustic wave (SAW) devices. Additionally, AlN's coefficient of thermal expansion (4.2 × 10⁻⁶) is relatively low. -6 K -1 With a low content of 0.5%, it can be used as a substrate material for semiconductor devices.

[0003] Due to the powerful functions of AlN, the preparation methods of AlN thin films have attracted widespread attention. Currently, common preparation methods include chemical vapor deposition, molecular beam epitaxy, and magnetron sputtering.

[0004] Chemical vapor deposition (CVD) is the most common method for preparing AlN nanostructures. It involves a gas-solid reaction. The main gas sources are N2 and NH3, while solid sources include Al powder, AlCl3, and Al2O3. By controlling factors such as growth time and temperature, AlN with different nanostructures can be obtained. Generally, CVD requires relatively high temperatures and sometimes necessitates the use of a catalyst.

[0005] Molecular beam epitaxy (MBE) is a growth method that allows for precise control of composition and concentration. AlN nanostructures grown by MBE are spontaneously formed under nitrogen-rich conditions. Unlike the continuous collisions of adsorbed atoms during thin film growth, the diffusion-driven process of adsorbed atoms is generally considered its growth mechanism. Adsorbed atoms on the substrate surface diffuse and migrate along the sidewalls of the nanostructure under the combined influence of surface chemical potential and adhesion coefficient, thus promoting the growth of the vertical nanostructure. This allows MBE to grow AlN with nanoarray structures without a template. Furthermore, as the substrate temperature increases, the axial growth rate of the AlN nanostructure is faster, and the aspect ratio of the product is larger. Therefore, the morphology of AlN varies significantly depending on the MBE growth temperature, requiring precise preparation parameters. Moreover, MBE technology places high demands on related equipment.

[0006] Magnetron sputtering uses an aluminum target and nitrogen (N2) as raw materials, with Ar as the carrier gas. Due to the ionization of the orthogonal magnetic field, Ar ions and N ions bombard the target material to produce aluminum nitride. The desired target product can be modulated by controlling the power supply, changing the reaction gas, and adjusting the voltage. However, magnetron sputtering equipment is complex and the material cost is relatively high.

[0007] Although various methods for preparing aluminum nitride thin films are disclosed in the prior art, they have problems such as complex preparation processes, the need for additives, high equipment requirements, and high requirements for preparation parameters. Summary of the Invention

[0008] To address the aforementioned shortcomings in the prior art, this invention provides an aluminum nitride thin film and its preparation method. The aluminum nitride thin film prepared by this method has the advantages of simple preparation method and high preparation efficiency, and can effectively solve the problems of high equipment requirements, high requirements for preparation parameters, and complex preparation process in the prior art.

[0009] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows:

[0010] A method for preparing an aluminum nitride thin film includes the following steps:

[0011] (1) Take an aluminum source, clean it and set it aside;

[0012] (2) The cleaned aluminum source is placed in the radio frequency plasma system and pretreated with ammonium salt plasma; then nitrogen plasma is used to treat the aluminum source; after the treatment is completed, inert gas is introduced and cooled to room temperature to obtain the product.

[0013] Furthermore, in step (1), ethanol is used to clean the aluminum source.

[0014] Furthermore, the aluminum source in step (1) includes one of aluminum foil, aluminum sheet, aluminum plate, alumina sheet, alumina foil, and alumina plate.

[0015] Furthermore, the thickness of the aluminum source in step (1) is 0.1-5 mm.

[0016] Furthermore, the radio frequency during the operation of the radio frequency plasma system in step (2) is 13.56MHz.

[0017] Furthermore, in step (2), the ammonium salt includes one of ammonium fluoride, ammonium chloride, ammonium bicarbonate, ammonium bisulfate, and ammonium nitrate.

[0018] Furthermore, in step (2), during the pretreatment of the aluminum source using ammonium salt plasma, the excitation temperature of the ammonium salt is 60-200℃, the processing power is 100-500W, the processing time is 5-20min, and the amount of ammonium salt used is 0.1-1g / cm³. 2 .

[0019] Furthermore, in step (2), the nitrogen source used to process the aluminum source with nitrogen plasma is either nitrogen or ammonia.

[0020] Furthermore, in step (2), during the process of treating the aluminum source with nitrogen plasma, the flow rate of the nitrogen source is 0.1-100 sccm, the treatment temperature is 400-1000℃, the treatment power is 500-1500W, and the treatment time is 5-30min.

[0021] An aluminum nitride thin film is prepared by the method described above.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The preparation method of aluminum nitride in this invention is simple, requiring only a radio frequency plasma system to complete the preparation. The reaction process is simple, short, and can be mass-produced, with the advantage of high production efficiency.

[0024] 2. The raw materials used in the preparation process of this invention are easy to obtain and have low cost. It does not use complex chemical components and does not require catalysts or other substances, thus having the advantage of low production cost.

[0025] 3. The method in this invention first uses ammonium salt plasma to treat the aluminum source. During the treatment, the ammonium salt is heated and volatilized into nitrogen plasma, which can etch and pre-activate the surface of the aluminum source, generating a nitrogen-containing seed activation layer. This can improve the uniformity and efficiency of subsequent nitrogen growth, thereby improving the performance and preparation efficiency of aluminum nitride films. Attached Figure Description

[0026] Figure 1The image shows the XRD pattern of the aluminum nitride film in Example 1.

[0027] Figure 2 The image shows the XRD pattern of the aluminum nitride film in Example 2.

[0028] Figure 3 The image shows the XRD pattern of the aluminum nitride film in Example 3.

[0029] Figure 4 The XPS full spectrum of the aluminum nitride thin film in Example 4;

[0030] Figure 5 This is a fine XPS spectrum of aluminum in the aluminum nitride film in Example 4;

[0031] Figure 6 This is a fine XPS spectrum of nitrogen in the aluminum nitride film in Example 5;

[0032] Figure 7 The image shows the XPS full spectrum of the aluminum nitride thin film in Example 6. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments.

[0034] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0036] The features and performance of the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0037] Example 1

[0038] An aluminum nitride thin film is prepared by means of the following steps:

[0039] (1) Take an aluminum foil with a size of 5×8cm and a thickness of 1mm, and wash it with ethanol for later use;

[0040] (2) The cleaned aluminum foil was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium fluoride plasma. During the treatment, the radio frequency was 13.56 MHz, the excitation temperature of the ammonium fluoride plasma was set to 100 ℃, the mass of ammonium fluoride was 0.1 g, the treatment power was 200 W, and the treatment time was 5 min. After the treatment, nitrogen was used as the nitrogen source to continue plasma treatment of the aluminum foil. During the treatment, the radio frequency was 13.56 MHz, the flow rate of the nitrogen source was 20 sccm, the treatment temperature was 500 ℃, the treatment power was 500 W, and the treatment time was 10 min. After the treatment, the heating was stopped and the nitrogen gas was stopped. Ar was introduced into it at a flow rate of 30 sccm. The solution was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1 mm.

[0041] Example 2

[0042] An aluminum nitride thin film is prepared by means of the following steps:

[0043] (1) Take an aluminum foil with a size of 5×8cm and a thickness of 1mm, and wash it with ethanol for later use;

[0044] (2) The cleaned aluminum foil was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium chloride plasma. During the treatment, the radio frequency was 13.56 MHz, the excitation temperature of the ammonium chloride plasma was set to 120 ℃, the mass of ammonium chloride was 0.5 g, the treatment power was 250 W, and the treatment time was 8 min. After the treatment, ammonia was used as the nitrogen source to continue plasma treatment of the aluminum foil. During the treatment, the radio frequency was 13.56 MHz, the flow rate of the nitrogen source was 20 sccm, the treatment temperature was 500 ℃, the treatment power was 500 W, and the treatment time was 10 min. After the treatment, the heating was stopped and the ammonia was stopped. Ar was introduced into it at a flow rate of 30 sccm. The solution was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1 mm.

[0045] Example 3

[0046] An aluminum nitride thin film is prepared by means of the following steps:

[0047] (1) Take an alumina plate with a size of 5×10cm and a thickness of 1mm, and wash it with ethanol for later use.

[0048] (2) The cleaned alumina plate was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium fluoride plasma. During the treatment, the radio frequency was 13.56 MHz, the excitation temperature of the ammonium fluoride plasma was set to 180 ℃, the mass of ammonium fluoride was 0.2 g, the treatment power was 200 W, and the treatment time was 5 min. After the treatment, nitrogen was used as the nitrogen source to continue plasma treatment of the alumina plate. During the treatment, the radio frequency was 13.56 MHz, the flow rate of the nitrogen source was 20 sccm, the treatment temperature was 700 ℃, the treatment power was 500 W, and the treatment time was 10 min. After the treatment, the heating was stopped and the nitrogen gas was stopped. Ar was introduced into it at a flow rate of 30 sccm. The plate was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1 mm.

[0049] Example 4

[0050] An aluminum nitride thin film is prepared by means of the following steps:

[0051] (1) Take an alumina plate with a size of 5×10cm and a thickness of 1mm, and wash it with ethanol for later use.

[0052] (2) The cleaned alumina plate was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium chloride plasma. During the treatment, the radio frequency was 13.56 MHz, the excitation temperature of the ammonium chloride plasma was set to 200 ℃, the mass of ammonium chloride was 1 g, the treatment power was 400 W, and the treatment time was 10 min. After the treatment, ammonia was used as the nitrogen source to continue plasma treatment of the aluminum source. During the treatment, the radio frequency was 13.56 MHz, the flow rate of the nitrogen source was 20 sccm, the treatment temperature was 700 ℃, the treatment power was 500 W, and the treatment time was 10 min. After the treatment, the heating was stopped and the ammonia was stopped. Ar was introduced into it at a flow rate of 30 sccm. The mixture was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1 mm.

[0053] Example 5

[0054] An aluminum nitride thin film is prepared by means of the following steps:

[0055] (1) Take an aluminum foil with a size of 5×8cm and a thickness of 1mm, and wash it with ethanol for later use;

[0056] (2) The cleaned aluminum foil was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium fluoride plasma. During the treatment, the radio frequency was 13.56 MHz, the excitation temperature of the ammonium fluoride plasma was set to 160 ℃, the mass of ammonium fluoride was 1 g, the treatment power was 200 W, and the treatment time was 5 min. After the treatment, nitrogen was used as the nitrogen source to continue plasma treatment of the aluminum foil. During the treatment, the radio frequency was 13.56 MHz, the flow rate of the nitrogen source was 20 sccm, the treatment temperature was 500 ℃, the treatment power was 500 W, and the treatment time was 25 min. After the treatment, the heating was stopped and the nitrogen gas was stopped. Ar was introduced into it at a flow rate of 30 sccm. The solution was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1 mm.

[0057] Example 6

[0058] An aluminum nitride thin film is prepared by means of the following steps:

[0059] (1) Take an alumina plate with dimensions of 5×8cm and a thickness of 1mm, and wash it with ethanol for later use.

[0060] (2) The cleaned alumina plate was placed in the quartz tube of the radio frequency plasma system. The aluminum source was pretreated with ammonium chloride plasma. During the treatment, the radio frequency frequency was 13.56MHz, the excitation temperature of the ammonium chloride plasma was set to 100℃, the mass of ammonium chloride was 4g, the treatment power was 500W, and the treatment time was 15min. After the treatment, nitrogen was used as the nitrogen source to continue plasma treatment of the aluminum foil. During the treatment, the radio frequency frequency was 13.56MHz, the flow rate of the nitrogen source was 20sccm, the treatment temperature was 900℃, the treatment power was 500W, and the treatment time was 25min. After the treatment, the heating was stopped and the nitrogen gas was stopped. Ar was introduced into it at a flow rate of 30sccm. The solution was cooled to room temperature to obtain an aluminum nitride film with a thickness of 1mm.

[0061] Experimental Example

[0062] Taking Examples 1-3 as examples, the aluminum nitride films prepared in Examples 1-3 were subjected to XRD and XPS detection, respectively. Specific detection results are shown in [the table below]. Figure 1-7 .

[0063] Figure 1 The image shows the XRD pattern of the aluminum nitride film in Example 1.

[0064] Figure 2 The image shows the XRD pattern of the aluminum nitride film in Example 2.

[0065] Figure 3 The image shows the XRD pattern of the aluminum nitride film in Example 3.

[0066] Figure 1-3 The blue line indicates the XRD pattern of the prepared sample, while the pink line indicates the standard curve of the characteristic peak of aluminum nitride. It can be seen that the aluminum nitride pattern prepared in Examples 1-3 is consistent with the characteristic peak of aluminum nitride, proving that aluminum nitride material was prepared in the examples.

[0067] Figure 4 The XPS full spectrum of the aluminum nitride thin film in Example 1;

[0068] Figure 5 This is a fine XPS spectrum of aluminum in the aluminum nitride film of Example 1;

[0069] Figure 6 This is a fine XPS spectrum of nitrogen in the aluminum nitride film in Example 2;

[0070] Figure 7 The image shows the XPS full spectrum of the aluminum nitride thin film in Example 2.

[0071] pass Figure 4 and Figure 7 It can be seen that the prepared material contains nitrogen; through Figure 5 and Figure 6 It can be seen from the perspective of aluminum that there are Al-N bonds in the material, which further proves that aluminum nitride has been formed.

Claims

1. A method for preparing an aluminum nitride thin film, characterized in that, Includes the following steps: An aluminum source was placed in a radio frequency plasma system with a radio frequency of 13.56 MHz. The aluminum source was first pretreated with ammonium salt plasma, and then treated with nitrogen plasma. After the treatment was completed, an inert gas was introduced and the mixture was cooled to room temperature to obtain the product. The aluminum source includes any one of aluminum foil, aluminum sheet, aluminum plate, alumina sheet, alumina foil, and alumina plate; Ammonium salts include any one of ammonium fluoride, ammonium chloride, ammonium bicarbonate, ammonium bisulfate, and ammonium nitrate.

2. The method for preparing aluminum nitride thin film as described in claim 1, characterized in that, Also includes: The aluminum source is cleaned with ethanol before use.

3. The method for preparing aluminum nitride thin film as described in claim 1, characterized in that, The thickness of the aluminum source is 0.1-5mm.

4. The method for preparing aluminum nitride thin film as described in claim 1, characterized in that, In the pretreatment of aluminum sources using ammonium salt plasma, the excitation temperature of the ammonium salt is 60-200℃, the processing power is 100-500W, the processing time is 5-20min, and the dosage of ammonium salt is 0.1-1g / cm³. 2 .

5. The method for preparing aluminum nitride thin film as described in claim 1, characterized in that, In the process of treating aluminum sources with nitrogen plasma, the nitrogen source is either nitrogen or ammonia.

6. The method for preparing aluminum nitride thin film as described in claim 1, characterized in that, During the treatment of aluminum source with nitrogen plasma, the flow rate of nitrogen source is 0.1-100 sccm, the treatment temperature is 400-1000℃, the treatment power is 500-1500W, and the treatment time is 5-30min.

7. An aluminum nitride thin film, characterized in that, It is prepared by the method according to any one of claims 1-6.

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