Aluminum nitride film growing on semiconductor substrate and preparation method and application thereof

Abstract

The invention relates to an aluminum nitride film growing on a semiconductor substrate and a preparation method and application thereof. The method comprises the following steps: cleaning the semiconductor substrate; the preparation method of the aluminum nitride laminated layer comprises the following steps: growing a first AlN layer on a semiconductor substrate by adopting an ALD deposition process; growing a second AlN layer on the surface of the first AlN layer by adopting a PVD (Physical Vapor Deposition) process to obtain a group of aluminum nitride laminated layers; the target material of the PVD deposition process is an AlN target material, the temperature range is within 20-300 DEG C, the air pressure of a PVD reaction chamber is within 0.1-2.0 Pa, and the flow ratio of nitrogen to argon in the reaction process is more than 1: 1; executing the preparation process of the aluminum nitride lamination at least once to obtain at least one group of aluminum nitride lamination; and the aluminum nitride laminated layer is annealed to obtain the aluminum nitride film, and the annealing temperature is lower than 1300 DEG C. The quality, the performance and the growth speed of the prepared aluminum nitride film are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum nitride films, and in particular to an aluminum nitride film grown on a semiconductor substrate, a preparation method thereof and an application thereof. Background Art

[0002] A1N is an important blue and ultraviolet luminescent material with a wide bandgap (6.2eV) and a direct bandgap. It has high thermal conductivity, high hardness, and high melting point. It can be used in high-temperature and high-power microelectronic devices and deep ultraviolet optoelectronic devices. A1N has stable chemical properties, good thermal stability, strong breakdown field (14KV / mm), low dielectric loss, high electromechanical coupling coefficient, and extremely high sensitivity to external environments such as pressure, temperature, stress, and gas. Its thermal expansion coefficient is similar to that of commonly used semiconductor materials such as Si and GaAs, and it is easily compatible with other semiconductor processes. Therefore, A1N material has become an ideal substrate material for the production of advanced high-power light-emitting devices (LED, LD), ultraviolet detectors, and high-power and high-frequency electronic devices. Aluminum nitride film is the best piezoelectric material in 5G high-frequency SAW / BAW filters and MEMS sensors.

[0003] The difficulty in preparing large-sized AlN single crystals is a key issue restricting the application of AlN. At present, AlN single crystals are mainly prepared by physical vapor transport (PVT), MOCVD or high-temperature magnetron sputtering technology. However, the cost of preparing AlN using PVT and MOCVD processes is relatively high, and the industrialization of AlN substrates is still immature and requires continuous technological progress. Compared with the mature MOCVD process, the cost of preparing AlN films using high-temperature magnetron sputtering technology is lower, but the quality of AlN films prepared by high-temperature magnetron sputtering is often poor. Summary of the invention

[0004] Based on this, it is necessary to provide an aluminum nitride film grown on a semiconductor substrate and a preparation method and application thereof to address the above problems. The aluminum nitride film is prepared by ALD process and PVD process under low temperature and low pressure environment, which improves the quality and performance of the aluminum nitride film and increases the growth rate of the aluminum nitride film.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a method for preparing an aluminum nitride film grown on a semiconductor substrate, comprising: cleaning the semiconductor substrate; preparing an aluminum nitride laminate; annealing the aluminum nitride laminate; wherein the aluminum nitride laminate preparation process comprises:

[0006] Growing a first AlN layer on the semiconductor substrate using an ALD deposition process;

[0007] A PVD deposition process is used to grow a second AlN layer on the surface of the first AlN layer to obtain a group of aluminum nitride stacked layers; the target material of the PVD deposition process is an AlN target material, the temperature range of the PVD deposition process is within 20° C.-300° C., the gas pressure of the PVD reaction chamber is within 0.1 Pa-2.0 Pa, and the flow ratio of nitrogen and argon during the reaction process is above 1:1;

[0008] Performing the aluminum nitride stacking process at least once to obtain at least one set of aluminum nitride stacking layers;

[0009] The annealing process is to anneal the semiconductor substrate on which the at least one set of aluminum nitride stacked layers are grown to obtain an aluminum nitride film, and the annealing temperature is less than 1300°C.

[0010] The embodiment of the present application can prepare aluminum nitride thin films and aluminum nitride thick films, and it is only necessary to control the number of times the aluminum nitride stack is prepared.

[0011] In other embodiments, the growing a first AlN layer on the semiconductor substrate using an ALD deposition process includes:

[0012] a. placing the semiconductor substrate in the ALD reaction chamber, evacuating the ALD reaction chamber to a vacuum degree of 1-2 mTorr, heating the ALD reaction chamber to a temperature of less than 300° C., and introducing a first inert gas as a carrier gas into the ALD reaction chamber;

[0013] b. introducing a precursor source TMA into the ALD reaction chamber and diffusing and adsorbing the precursor source TMA on the semiconductor substrate;

[0014] c. introducing a first inert gas into the ALD reaction chamber to purge the surface of the semiconductor substrate to remove excess precursor source TMA;

[0015] d. Plasma NH3 is introduced into the ALD reaction chamber to react with the precursor source TMA adsorbed on the semiconductor substrate;

[0016] e. Introducing a second inert gas into the ALD reaction chamber to purge the surface of the semiconductor substrate to remove excess plasma NH3 and reaction byproducts;

[0017] f. Repeat steps b, c, d, and e several times to obtain a first AlN layer of a preset thickness.

[0018] In other embodiments, the temperature of the ALD reaction chamber after heating in step a is 200° C.-250° C.;

[0019] And / or, in step b, the temperature of the precursor source TMA is maintained at 15° C.-25° C., and the pulse time of the precursor source TMA is 0.01-1 second;

[0020] And / or, in step c, the first inert gas purge time is 5-10 seconds;

[0021] And / or, in step d, the pulse time of plasma NH3 introduced into the ALD reaction chamber is 10-15 seconds, and the RF power is 900W-1100W;

[0022] And / or, in step e, the first inert gas and the second inert gas are different, and the purge time of the second inert gas is 10-15 seconds.

[0023] In other embodiments, the temperature of the ALD reaction chamber after heating in step a is 220° C., and the first inert gas is nitrogen;

[0024] And / or, in step b, the temperature of the precursor source TMA is maintained at 20° C., and the pulse time of the precursor source TMA is 0.08 seconds;

[0025] And / or, in step c, the first inert gas purge time is 6 seconds;

[0026] And / or, in step d, the pulse time of plasma NH3 introduced into the ALD reaction chamber is 12 seconds and the RF power is 1000W;

[0027] And / or, in step e, the second inert gas is argon, and the purge time of the second inert gas is 12 seconds.

[0028] In other embodiments, the temperature of the PVD deposition process is 20°C, or 100°C, or 150°C.

[0029] In other embodiments, the gas pressure of the PVD reaction chamber is within 0.3Pa-1.5Pa.

[0030] In other embodiments, the gas pressure of the PVD reaction chamber is 0.3Pa, or 0.5Pa, or 0.6Pa, or 1.5Pa.

[0031] In other embodiments, the flow ratio of nitrogen to argon during the reaction is 1:1, 2:1 or 3:1.

[0032] In other embodiments, the annealing temperature is 1000° C., and the annealing time is 0.5 h-1 h.

[0033] In other embodiments, in the PVD deposition process, the background vacuum of the PVD reaction chamber is less than 10-4 Pa, preferably, the background vacuum of the PVD reaction chamber is 5.9*10 -5 Pa to 9.9*10 -5 Pa, sputtering power is within 150W-500W, argon flow rate is within 10sccm-20sccm, and nitrogen flow rate is within 20sccm-60sccm.

[0034] On the other hand, the embodiment of the present application also provides an aluminum nitride film prepared by the aluminum nitride film preparation method described above, wherein the aluminum nitride film includes one or more aluminum nitride stacks. In other words, the aluminum nitride film can be an aluminum nitride thin film or an aluminum nitride thick film.

[0035] On the other hand, an embodiment of the present application includes the aluminum nitride film electrical component described above.

[0036] On the other hand, the application of the aluminum nitride thin film preparation method, aluminum nitride film or electrical component described in an embodiment of the present application in the field of materials or optoelectronic devices.

[0037] The present invention adopts an ALD deposition process to grow a first AlN layer on the semiconductor substrate, and then adopts a low-temperature and low-pressure PVD deposition process to grow a second AlN layer on the surface of the first aluminum nitride film to obtain a set of aluminum nitride stacks; then the aluminum nitride stack is subjected to low-temperature annealing to obtain an aluminum nitride film. The first AlN layer serves as a buffer layer between the semiconductor substrate and the second AlN layer, which can avoid the lattice mismatch and excessive stress caused by the direct contact between the second AlN layer prepared by the PVD process and the semiconductor substrate.

[0038] Moreover, the target material of the PVD deposition process in the present application is an AlN target material, and the parameters of the PVD deposition process are low temperature and low pressure, that is, the temperature range is within 20°C-300°C, the gas pressure of the PVD reaction chamber is within 0.1Pa-2.0Pa, and the flow ratio of nitrogen and argon in the reaction process is above 1:1. The low temperature process of the PVD process can avoid the disadvantages of high temperature reaction caused by high temperature magnetron sputtering in the prior art, and sputtering AlN at low pressure reduces the concentration of gas molecules in the PVD reaction chamber, increases the mean free path of the sputtered particles, and makes more particles reach the substrate surface per unit time to participate in the deposition process, thereby improving the density and growth efficiency of the AlN film to a certain extent. The AlN film prepared by the method of the present application has high density and uniformity, improves the growth efficiency of the AlN film, and reduces the preparation cost of the AlN film. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 A flowchart of a method for preparing an aluminum nitride film grown on a semiconductor substrate provided for one embodiment of the present application;

[0041] Figure 2 ALD process flow chart of a method for preparing an aluminum nitride film grown on a semiconductor substrate provided in one embodiment of the present application;

[0042] Figure 3 A SEM image of a cross section of an aluminum nitride film prepared by a method for preparing an aluminum nitride film grown on a semiconductor substrate provided in one embodiment of the present application;

[0043] Figure 4 XRD diagram of aluminum nitride films prepared at different deposition temperatures in the PVD deposition process provided in the embodiments of the present application;

[0044] Figure 5 XRD diagram of aluminum nitride films prepared with different nitrogen-argon ratios in the PVD deposition process provided in the embodiments of the present application;

[0045] Figure 6 XRD diagram of aluminum nitride films prepared at different working gas pressures in the PVD deposition process provided in the embodiment of the present application;

[0046] Figure 7-10 SEM images of cross sections of aluminum nitride films prepared with different PVD deposition parameters provided in Comparative Examples 1-4, respectively;

[0047] Fig.11 A SEM image of a cross section of an aluminum nitride film prepared by a conventional high-temperature magnetron sputtering process provided in Comparative Example 5;

[0048] Fig.12 This is a SEM image of the cross section of the aluminum nitride thick film grown on a semiconductor substrate prepared by the method for preparing an aluminum nitride film provided in Example 8 of the present application. DETAILED DESCRIPTION

[0049] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0050] As described in the background technology, the AlN film prepared by the PVT and MOCVD methods in the prior art is high in cost, and the AlN film prepared by high-temperature magnetron sputtering is low in cost, but the film quality is poor. The inventors have found that the reason why the AlN film grown by high-temperature magnetron sputtering is of poor quality is that the target material generally used in high-temperature magnetron sputtering is an Al target or an AlN target. Using an Al target, it is necessary to react with nitrogen ions under a high temperature environment to generate AlN. On the one hand, it is easy to produce impurities such as aluminum oxide. In addition, the film texture is loose, causing the adhesion between the film and the substrate to deteriorate, and the AlN film is easy to fall off from the substrate. Similarly, using an AlN target, it is also necessary to be under a high temperature environment. The AlN amorphous material sputtered on the AlN target has disorder. When deposited on a heterogeneous semiconductor substrate, it will cause an increase in residual stress in the film. Similarly, as the stress increases during the growth process, it will accumulate to a certain extent and affect the quality of the film, such as the film becomes loose and easily falls off from the substrate, etc., and the average growth rate of the high-temperature sputtered film is low, and it is difficult to achieve the growth of thick films.

[0051] Based on this, an embodiment of the present invention provides a method for preparing an aluminum nitride film grown on a semiconductor substrate, such as Figure 1 As shown, the method comprises the following steps:

[0052] Step S1: providing a semiconductor substrate and cleaning the semiconductor substrate. The semiconductor substrate may be cleaned by a standard RCA method to prevent impurities from affecting the quality of the subsequently grown aluminum nitride single crystal.

[0053] The semiconductor substrate is a heterogeneous semiconductor substrate, and the semiconductor substrate material can be single crystal, polycrystalline or amorphous silicon or silicon germanium (SiGe), or can include a mixed semiconductor structure, such as silicon carbide, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide or gallium antimonide, alloy semiconductors or combinations thereof, or can be silicon on insulator (SOI).

[0054] Step S2: Aluminum nitride stack preparation, the process includes the following steps:

[0055] Step S21: using an ALD deposition process to grow a first AlN layer on the semiconductor substrate.

[0056] The atomic layer deposition (ALD) process is a highly precise thin film growth technology that can deposit materials layer by layer at the nanoscale to form a film with excellent uniformity, density and controllable thickness. Due to its self-limiting reaction characteristics, the ALD process can achieve uniform film coverage on the surface of complex three-dimensional structures. The ALD process is particularly suitable for the preparation of high-quality nitride semiconductor materials, such as aluminum nitride (AlN). Therefore, the first AlN layer grown by the ALD process has good density and uniformity.

[0057] Step S22: using a PVD deposition process to grow a second AlN layer on the surface of the first AlN layer to obtain a group of aluminum nitride stacks; the target material of the PVD deposition process is an AlN target material, the temperature range of the PVD deposition process is within 20°C-300°C, the gas pressure of the PVD reaction chamber is within 0.1Pa-2.0Pa, the flow ratio of nitrogen and argon during the reaction process is above 1:1, and the deposition time is determined according to the thickness of the prepared second AlN layer.

[0058] In addition to the above parameter restrictions, in other embodiments, during the PVD deposition process, the background vacuum of the PVD reaction chamber is less than 10 -4 Pa, preferably, the background vacuum of the PVD reaction chamber is 5.9*10 -5 Pa to 9.9*10 -5 Pa, sputtering power is within 150W-500W, argon flow rate is within 10sccm-20sccm, and nitrogen flow rate is within 20sccm-60sccm.

[0059] It should be noted that the background vacuum of the PVD reaction chamber is related to the time of evacuating the reaction chamber before the actual reaction. In this application, the background vacuum of the PVD reaction chamber is less than 10 -4 Pa can meet the quality requirements of aluminum nitride film, and the background vacuum degree is 5.9*10 -5 Pa to 9.9*10 -5 The specific value within Pa has little effect on the quality of the aluminum nitride film. Similarly, the choice of sputtering power is related to the distance between the target and the substrate. As long as a large proportion of the sputtered particles can reach the substrate within a reasonable distance, the distance between the target and the substrate in this embodiment is preferably 10-18cm, more preferably 15cm, and the sputtering power is preferably within 150-400w. Moreover, during the entire PVD process, the flow rates of nitrogen and argon change dynamically. As long as the working gas pressure and nitrogen-argon ratio of the reaction chamber are kept stable, the specific flow rates of nitrogen and argon have little effect on the quality of the aluminum nitride film.

[0060] The first AlN layer is used as a buffer layer, and the second AlN layer is grown on the surface of the first AlN layer, which can avoid the lattice mismatch and excessive stress problems caused by the direct contact between the AlN prepared by magnetron sputtering and the heterogeneous semiconductor substrate. That is, at the interface between the first AlN layer and the second AlN layer, stress release can be effectively achieved, thereby improving the adhesion between the first AlN layer and the second AlN layer, and also improving the growth rate of the AlN film.

[0061] Furthermore, the second AlN layer is grown under a low working pressure within 0.1Pa-2.0Pa, which reduces the concentration of gas molecules in the reaction chamber, increases the mean free path of sputtered particles, and enables more particles to reach the substrate surface to participate in the deposition process per unit time, thereby improving the growth efficiency of the second AlN layer. At the same time, the use of AlN targets can avoid the high-temperature reaction environment when using Al targets, that is, it can ensure that the AlN film can survive in a low-temperature environment, and, on the basis of a certain oxygen content in the PVD reaction chamber, the use of a low-temperature growth environment of 20°C-300°C can slow down the oxidation process and reduce the formation of aluminum oxide impurities, thereby improving the uniformity and density of the second AlN layer.

[0062] Moreover, during the PVD process, the plasma atmosphere in the reaction chamber is nitrogen and argon. Ar plasma can ensure the effective sputtering process of the AlN target, and the N2-rich environment (i.e., high nitrogen-argon ratio, the flow ratio of nitrogen and argon ≥1:1) can further inhibit the formation of nitrogen vacancies and Al-rich regions in the AlN growth process film, making the film denser and the crystal quality higher.

[0063] Therefore, compared with the AlN film grown under a high temperature and high pressure reaction scenario in the prior art, the second AlN layer grown by the PVD process in the embodiment of the present application has high uniformity and density, high crystal quality, and high growth efficiency.

[0064] In other embodiments, the temperature of the PVD deposition process may be 20° C., or 100° C., or 150° C. The gas pressure of the PVD reaction chamber is within 0.3 Pa-1.5 Pa. More preferably, the gas pressure of the PVD reaction chamber may be 0.3 Pa, or 0.5 Pa, or 0.6 Pa, or 1.5 Pa. The flow ratio of nitrogen and argon during the reaction process is 1:1, or 3:1.

[0065] Step S23: performing the aluminum nitride stack preparation process at least once to obtain at least one group of aluminum nitride stacks.

[0066] By adopting the method of the embodiment of the present application, aluminum nitride thin films or aluminum nitride thick films can be grown. It is only necessary to repeat the ALD+PVD process of growing aluminum nitride stacks. According to the thickness requirements of the aluminum nitride film to be prepared, the aluminum nitride stack preparation process can be repeated a certain number of times.

[0067] In the prior art, aluminum nitride films are prepared by high-temperature sputtering process. Due to the lattice mismatch and the continuous accumulation of internal stress in the film during the high-temperature growth process, the film will have holes and the film will be loose and not dense. This will make it impossible for subsequent AlN particles to continue to grow effectively on the surface of the film. In other words, it is difficult to make a breakthrough in the thickness of aluminum nitride films prepared by high-temperature sputtering process, and the growth rate is slow.

[0068] Moreover, the first AlN layer grown by the ALD process in the embodiment of the present application only serves as a buffer layer to release the interface stress between the first AlN layer and the second AlN layer, rather than as a seed layer. Therefore, before growing the second AlN layer, it is not necessary to crystallize the first AlN layer at a high temperature to form a small seed crystal. It should be noted that the first AlN layer generally crystallizes at 500°C-800°C. In other words, in the embodiment of the present application, after the first AlN layer is formed, it is not necessary to keep the first AlN layer in a temperature environment of 500°C-800°C in the subsequent process.

[0069] Furthermore, since the multi-layer aluminum nitride stack in the embodiment of the present application has been stress-released at the interface between the first AlN layer and the second AlN layer during repeated ALD+PVD processes, frequent annealing is not required to release stress. In other words, compared with the prior art process of growing an aluminum nitride seed layer using ALD and growing an aluminum nitride layer using high-temperature PVD, and the process of directly growing an aluminum nitride film using high-temperature sputtering, the efficiency of growing a multi-layer aluminum nitride stack of the same thickness is higher in the embodiment of the present application, and the number and time of annealing required are also shorter.

[0070] Step S3: Annealing the aluminum nitride stack. Specifically, the semiconductor substrate having the at least one group of aluminum nitride stacks grown thereon is placed in a tube furnace and annealed in a vacuum environment to obtain an aluminum nitride film. The annealing temperature is less than 1300°C. In other embodiments, the annealing temperature is 1000°C and the annealing time is 0.5h-1h. The annealing time in this embodiment can be reasonably controlled. The specific annealing time has a limited effect on the quality of the aluminum nitride film, and this embodiment does not make too many restrictions on this.

[0071] It is understandable that the existence of stress in the aluminum nitride film is derived from the disorder of the film itself and the common effect of lattice mismatch with the substrate. The annealing process can improve the disorder of the amorphous film to a certain extent, so the accumulated stress will be reduced, that is, the stress of the film layer is released. The embodiment of the present application further anneals the aluminum nitride stack, which can further release the residual stress in the aluminum nitride stack and improve the quality of the aluminum nitride film. In addition, the temperature of the annealing process is lower than that of the conventional annealing process (generally 1500°C and above), which also avoids the precipitation of aluminum oxide impurities in the aluminum nitride stack to a certain extent.

[0072] It should be noted that, since most of the stress has been released between the interface of the first aluminum nitride layer and the second aluminum nitride layer, the annealing process in the embodiment of the present application only needs to be performed once after the multi-layer aluminum nitride stack is formed, and the intermediate process of forming the multi-layer aluminum nitride stack does not need annealing. It is not necessary to perform annealing after each ALD process grows a layer of aluminum nitride film in order to form a seed crystal and play a role in seeding, as in the prior art, nor is it necessary to perform annealing after forming a certain thickness of aluminum nitride layer in order to reduce void defects as in the prior art.

[0073] In another embodiment of the present application, the method for preparing aluminum nitride is disclosed, and the process of step S21 is as follows: Figure 2 As shown, the process of growing the first AlN layer on the semiconductor substrate using the ALD deposition process specifically includes the following steps:

[0074] Step S211: Place the semiconductor substrate in the ALD reaction chamber, evacuate the ALD reaction chamber to a vacuum degree of 1-2 mTorr, heat the ALD reaction chamber to a temperature less than 300°C, and introduce a first inert gas as a carrier gas into the ALD reaction chamber. In this embodiment, the first inert gas is preferably nitrogen. In other embodiments, the temperature of the ALD reaction chamber after heating is 200°C-250°C, and more preferably, the temperature of the ALD reaction chamber after heating is 220°C.

[0075] Step S212: introducing a precursor source TMA into the ALD reaction chamber and diffusing and adsorbing the precursor source TMA on the semiconductor substrate. In other embodiments, the temperature of the precursor source TMA is maintained at 15°C-25°C, and the pulse time of the precursor source TMA is 0.01-1 second; more preferably, the temperature of the precursor source TMA is maintained at 20°C, and the pulse time of the precursor source TMA is 0.08 second.

[0076] Step S213: introducing a first inert gas into the ALD reaction chamber to purge the surface of the semiconductor substrate to purge excess precursor source TMA. In other embodiments, the first inert gas purge time is 5-10 seconds; more preferably, the first inert gas purge time is 6 seconds.

[0077] Step S214: Plasma NH3 is introduced into the ALD reaction chamber to react with the precursor source TMA adsorbed on the semiconductor substrate. In other embodiments, the pulse time of plasma NH3 introduced into the ALD reaction chamber is 10-15 seconds, and the RF power is 900W-1100W; more preferably, the pulse time of plasma NH3 introduced into the ALD reaction chamber is 12 seconds, and the RF power is 1000W.

[0078] Step S215: A second inert gas is introduced into the ALD reaction chamber to purge the surface of the semiconductor substrate to purge excess plasma NH3 and reaction byproducts. The first inert gas and the second inert gas are different, the first inert gas is nitrogen, and the second inert gas is argon. In other embodiments, the purge time of the second inert gas is 10-15 seconds, and more preferably, the purge time of the second inert gas is 12 seconds.

[0079] Step S216: Repeat steps S212 to S215 for several times to obtain a first AlN layer with a preset thickness.

[0080] It should be noted that the higher the thickness of the first AlN layer, the better the crystal phase consistency. If the first AlN layer is used as a seed crystal, the higher the thickness of the first AlN layer, the better. However, the first AlN layer in the embodiment of the present application mainly serves as a buffer layer, so the thickness of the first AlN layer can be moderate, and there is no need to pursue a relatively high thickness.

[0081] Other embodiments of the present application also disclose an aluminum nitride film, which is prepared by the aluminum nitride film preparation method described in any of the above embodiments, and the aluminum nitride film includes one or more aluminum nitride stacks. Compared with the aluminum nitride film generated by high-temperature sputtering in the prior art, the aluminum nitride film has better density and uniformity.

[0082] Other embodiments of the present application also disclose electrical components comprising an aluminum nitride film prepared by the aluminum nitride film preparation method described in any of the above embodiments.

[0083] Other embodiments of the present application also disclose the application of the aluminum nitride film preparation method described in any of the above embodiments, and the application of the prepared aluminum nitride film or electrical components using the aluminum nitride film in the field of materials or optoelectronic devices.

[0084] Hereinafter, the aluminum nitride film and the preparation method thereof disclosed in the embodiments of the present application will be further described through the following specific examples.

[0085] Example 1

[0086] Step S41: providing a SiC substrate, and cleaning the SiC substrate using a standard RCA method to remove impurities on the surface of the substrate.

[0087] Step S42: placing the semiconductor substrate in the ALD reaction chamber, evacuating the ALD reaction chamber to a vacuum degree of 1-2 mTorr, heating the ALD reaction chamber to 220° C., and introducing nitrogen as a carrier gas into the ALD reaction chamber.

[0088] Step S43: introducing a precursor source TMA into the ALD reaction chamber, diffusing and adsorbing on the SiC substrate, maintaining the temperature of the precursor source TMA at 20° C., and the pulse time of introducing the precursor source TMA is 0.08 seconds.

[0089] Step S44: nitrogen gas is introduced into the ALD reaction chamber to purge the surface of the SiC substrate to purge away excess precursor source TMA. The nitrogen purge time is 6 seconds.

[0090] Step S45: Plasma NH3 is introduced into the ALD reaction chamber to react with the precursor source TMA adsorbed on the semiconductor substrate. The pulse time of the plasma NH3 is 12 seconds and the RF power is 1000W.

[0091] Step S46: Argon gas is introduced into the ALD reaction chamber to purge the surface of the SiC substrate to remove excess plasma NH3 and reaction by-products. The argon gas purge time is 12 seconds.

[0092] Step S47: Repeat steps S42 to S46 for multiple times to obtain a first AlN layer with a theoretical thickness of 50 nm.

[0093] Step S48: using a PVD deposition process to grow a second AlN layer on the surface of the first AlN layer to obtain a set of aluminum nitride stacked layers.

[0094] In the PVD deposition process, an AlN target with an AlN content of 99.99% is selected, and the background vacuum of the PVD reaction chamber is 10 -5Pa order of magnitude, the distance between the AlN target and the SiC substrate is controlled in a reasonable range, such as 15cm; the sputtering power ensures that most of the sputtered particles can reach the SiC substrate smoothly, such as the sputtering power is controlled at 150w; the nitrogen-argon ratio is controlled at 3:1, and the working gas pressure is 0.5Pa, for example, the nitrogen flow rate can be adjusted around 45Sccm, and the argon flow rate can be adjusted around 15Sccm; the deposition temperature is 100℃, and a second AlN layer of a certain thickness is deposited, such as 200nm-700nm.

[0095] Step S49: placing the SiC substrate with the aluminum nitride laminate obtained in S48 in a tube furnace and annealing it in a vacuum environment at a temperature of 1000° C. for 1 hour.

[0096] The SEM interface image of the aluminum nitride film prepared by the aluminum nitride film preparation method of this embodiment is as follows: Figure 3 As shown (the main cross-sectional morphology of the second aluminum nitride layer can be clearly seen in the figure), from Figure 3 It can be seen that the density and uniformity of the aluminum nitride film are both high.

[0097] Example 2

[0098] The other processes are the same as those in Example 1, except that in step S48, the deposition temperature of PVD is 20°C.

[0099] Example 3

[0100] The other processes are the same as those in Example 1, except that in step S48, the deposition temperature of PVD is 150°C.

[0101] Example 4

[0102] The other processes are the same as those in Example 1, except that in step S48, the deposition temperature of PVD is 300°C.

[0103] Example 2-Example 4, the XRD patterns of aluminum nitride films prepared at different deposition temperatures are as follows: Figure 4 As shown, the horizontal axis is the 2θ angle and the vertical axis is the XRD intensity. Experiments have shown that the aluminum nitride film prepared at different deposition temperatures has a good (002) preferred orientation growth, that is, the aluminum nitride film C-axis orientation (002) crystal phase is enhanced.

[0104] Example 5

[0105] The other processes are the same as those in Example 1, except that in step S48, the nitrogen-argon ratio of PVD is 1:1.

[0106] Example 1 and Example 5, the XRD patterns of the samples prepared with different nitrogen-argon ratios are shown in Figure 5As shown, the experiment proves that the XRD diffraction peaks of the aluminum nitride films prepared under different nitrogen-argon ratios show that the aluminum nitride films have good (002) preferred orientation growth, that is, the C-axis oriented (002) crystal phase of the aluminum nitride film is enhanced.

[0107] Example 6

[0108] The other processes are the same as those in Example 1, except that in step S48, the working gas pressure of PVD is 0.3 Pa.

[0109] Example 7

[0110] The other processes are the same as those in Example 1, except that in step S48, the working gas pressure of PVD is 0.6 Pa.

[0111] Example 8

[0112] The other processes are the same as those in Example 1, except that in step S48, the working gas pressure of PVD is 1.5 Pa.

[0113] Examples 6-8, XRD patterns prepared at different working pressures are shown in Figure 6 As shown, the experiment proves that the aluminum nitride film prepared under different working pressures has a good (002) preferred orientation growth, that is, the C-axis orientation (002) crystal phase of the aluminum nitride film is enhanced.

[0114] Comparative Example 1

[0115] The difference between Comparative Example 1 and Example 1 is that in step S48, the temperature of the PVD deposition process is 600° C. The SEM interface image of the prepared aluminum nitride film is as follows: Figure 7 As shown (the main cross-sectional morphology of the second aluminum nitride layer can be clearly seen in the figure), from Figure 3 and Figure 7 It can be seen from the comparison that Figure 7 The density and uniformity of aluminum nitride film are relatively Figure 3 Difference.

[0116] Comparative Example 2

[0117] The difference between Comparative Example 2 and Example 1 is that in step S48, the nitrogen-argon ratio of the PVD deposition process is 1:3. The SEM interface image of the prepared aluminum nitride film is as follows: Figure 8 As shown (the main cross-sectional morphology of the second aluminum nitride layer can be clearly seen in the figure), from Figure 3 and Figure 8 It can be seen from the comparison that Figure 8 The density and uniformity of aluminum nitride film are relatively Figure 3 There is a big difference, and the aluminum nitride film contains more Al element-rich areas precipitated in the film, and the quality of the aluminum nitride film is low.

[0118] Comparative Example 3

[0119] The only difference between Comparative Example 3 and Example 1 is that in step S48, the working pressure of the PVD deposition process is 5 Pa, and the SEM interface image of the prepared aluminum nitride film is as follows: Fig. 9 As shown (the main cross-sectional morphology of the second aluminum nitride layer can be clearly seen in the figure), from Figure 3 and Fig. 9 It can be seen from the comparison that Fig. 9 The density and uniformity of aluminum nitride film are relatively Figure 3 There is a big difference, and the aluminum nitride film contains more holes and the quality of the aluminum nitride film is low.

[0120] Comparative Example 4

[0121] The difference between Comparative Example 4 and Example 1 is that in step S49, the annealing temperature is 1600° C. The SEM interface image of the prepared aluminum nitride film is as follows: Fig.10 As shown (the main cross-sectional morphology of the second aluminum nitride layer can be clearly seen in the figure), from Figure 3 and Fig.10 It can be seen from the comparison that Fig.10 The density and uniformity of aluminum nitride film are relatively Figure 3 In addition, a large amount of Al element is precipitated in the aluminum nitride film, and the quality of the aluminum nitride film is low.

[0122] From the above examples 1-8 and comparative examples 1-4, it can be clearly judged that the aluminum nitride film prepared by the aluminum nitride preparation method disclosed in the examples of the present application has high density and uniformity. In addition, considering factors such as equipment cost and maintenance cost, the cost of the PVD process is much lower than that of MOCVD, PVT and other processes.

[0123] Comparative Example 5

[0124] like Fig.11 As shown, a cross-sectional SEM image of an aluminum nitride film grown directly on a SiC substrate by a high-temperature magnetron sputtering process in the prior art is sampled. The growth temperature is 500°C, the working gas pressure is 8.0 Pa, the nitrogen-argon ratio is 3:1, and the nitrogen flow rate is adjusted around 30 Sccm and the argon flow rate can be adjusted around 10 Sccm to achieve control of the nitrogen-argon ratio. The sputtering time is 2 h, and the thickness of the grown AlN film is 327 nm. The growth rate of the AlN film is calculated to be 2.725 nm / min.

[0125] Example 9

[0126] The difference between Example 9 and Example 1 is that in step S48, the deposition temperature of PVD is 100°C, the working pressure is 2Pa, the nitrogen-argon ratio is 2:1, and the nitrogen flow rate is controlled to be adjusted around 30 Sccm, and the argon flow rate can be adjusted to be around 15 Sccm to achieve the control of the nitrogen-argon ratio. The ALD deposition process and the PVD deposition process are repeated three times to grow the aluminum nitride stack, and the first to third aluminum nitride stacks are obtained on the SiC substrate in sequence, and the cross-sectional SEM image of the aluminum nitride thick film is obtained as shown in FIG. Fig.12 As shown, from Fig.12 It can be seen that the interface between the alternating growth of ALD and PVD processes is clear, and the density and uniformity of each film layer are high.

[0127] In the aluminum nitride thick film prepared in this embodiment, the thickness of the first AlN film in the first aluminum nitride stack is 68.51nm, the thickness of the second AlN film is 385.1nm, the magnetron sputtering time of the PVD process is 2h, and the growth rate of the second AlN film is calculated to be 3.2nm / min, which is 18.5% higher than the growth rate of the AlN film directly sputtered at high temperature on the SiC substrate; the thickness of the first AlN film in the second aluminum nitride stack is 94.49nm, the thickness of the second AlN film is 616.6nm, and the magnetron sputtering time of the PVD process is 2h. The sputtering time is 2 hours, and it is calculated that the growth rate of the second AlN film is 5.1 nm / min, which is 88.9% higher than the growth rate of the AlN film directly sputtered by high-temperature magnetron sputtering on the SiC substrate; the thickness of the first AlN film in the third aluminum nitride stack is 51.97 nm, the thickness of the second AlN film is 282.2 nm, and the magnetron sputtering time of the PVD process is 1 hour. It is calculated that the growth rate of the AlN sublayer is 4.8 nm / min, which is 77.8% higher than the growth rate of the AlN film directly sputtered by high-temperature magnetron sputtering on the SiC substrate.

[0128] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0129] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing an aluminum nitride film grown on a semiconductor substrate, characterized in that: include: Cleaning semiconductor substrates; Aluminum nitride stack preparation; Annealing the aluminum nitride stack; wherein the aluminum nitride stack preparation process includes: Growing a first AlN layer on the semiconductor substrate using an ALD deposition process; A PVD deposition process is used to grow a second AlN layer on the surface of the first AlN layer to obtain a group of aluminum nitride stacked layers; the target material of the PVD deposition process is an AlN target material, the temperature range of the PVD deposition process is within 20° C.-300° C., the gas pressure of the PVD reaction chamber is within 0.1 Pa-2.0 Pa, and the flow ratio of nitrogen and argon during the reaction process is above 1:1; Performing the aluminum nitride stacking process at least once to obtain at least one set of aluminum nitride stacking layers; The annealing process is to anneal the semiconductor substrate on which the at least one set of aluminum nitride stacked layers are grown to obtain an aluminum nitride film, and the annealing temperature is less than 1300°C.

2. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to claim 1, characterized in that: The temperature of the PVD deposition process is 20°C, or 100°C, or 150°C.

3. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to claim 1, characterized in that: The gas pressure of the PVD reaction chamber is within 0.3Pa-1.5Pa.

4. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to claim 1, characterized in that: The gas pressure of the PVD reaction chamber is 0.3Pa, or 0.5Pa, or 0.6Pa, or 1.5Pa.

5. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to claim 1, characterized in that: The flow ratio of nitrogen to argon during the reaction is 1:1, 2:1 or 3:

1.

6. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to claim 1, characterized in that: The annealing temperature is 1000° C., and the annealing time is 0.5 h-1 h.

7. The method for preparing an aluminum nitride film grown on a semiconductor substrate according to any one of claims 1 to 6, characterized in that: In the PVD deposition process, the background vacuum of the PVD reaction chamber is less than 10 -4 Pa, sputtering power is within 150W-500W, argon flow rate is within 10sccm-20sccm, and nitrogen flow rate is within 20sccm-60sccm.

8. An aluminum nitride film, characterized in that: The aluminum nitride film is prepared by the aluminum nitride film preparation method according to any one of claims 1 to 7, wherein the aluminum nitride film comprises one or more groups of aluminum nitride stacks.

9. An electrical component, characterized in that: The electrical component includes the aluminum nitride film according to claim 8.

10. Use of the method for preparing an aluminum nitride film grown on a semiconductor substrate according to any one of claims 1 to 7, the aluminum nitride film according to claim 8, or the electrical component according to claim 9 in the field of materials or optoelectronic devices.

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