A self-limiting reaction-regulated atomic layer deposition method of wurtzite ferroelectric material
By depositing AlN/BN or ZnO/MgO thin films in wurtzite ferroelectric materials, the problems of poor interfacial adhesion and self-limited growth were solved, enabling the fabrication of high-performance ferroelectric memory and improving the reliability and production efficiency of the devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIDIAN UNIV HANGZHOU RES INST
- Filing Date
- 2026-03-10
- Publication Date
- 2026-05-29
AI Technical Summary
Existing wurtzite ferroelectric material preparation technologies suffer from problems such as poor interfacial bonding, easy film peeling, difficulty in controlling internal stress, multiphase coexistence, and self-limiting growth, resulting in unstable device performance and low production efficiency.
Atomic layer deposition technology is used to deposit AlN and BN thin films or ZnO and MgO thin films, providing initial active sites and controlling the film thickness and doping concentration, thereby removing self-limiting growth and realizing the growth of wurtzite ferroelectric thin films of arbitrary thickness and doping concentration.
This improved the interfacial adhesion and electrical properties of wurtzite ferroelectric thin films, enabling the fabrication of high-performance, reliable ferroelectric storage devices and enhancing production efficiency and the flexibility of material combinations.
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Figure CN122105369A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of ferroelectric materials technology and semiconductor memory manufacturing technology, and particularly to a method for atomic layer deposition of wurtzite ferroelectric materials with self-limited reaction regulation. Background Technology
[0002] Currently, the traditional von Neumann architecture based on memory-computation separation faces the "memory wall" and "power wall" problems, making it difficult to meet the ever-increasing demands for computing power and energy efficiency. Meanwhile, the microelectronics and integrated circuit industries urgently need new electronic devices with high computing power, low latency, and low power consumption. Against this backdrop, wurtzite ferroelectric memory (WFEM) is considered a potential candidate technology for in-memory computing due to its advantages such as large memory window, low thermal budget, and good compatibility with integrated circuit processes.
[0003] However, existing technologies for preparing wurtzite ferroelectric materials still face several challenges: both mainstream preparation methods encounter insurmountable technical bottlenecks, hindering performance improvement and industrialization. On the one hand, the interfacial bonding between the film and substrate prepared by physical vapor deposition (PVD) is weak, resulting in poor film adhesion and easy peeling during subsequent device processing or long-term use. At the same time, the internal stress of the film prepared by PVD is difficult to control effectively, which can easily lead to cracking and directly affect the electrical performance and lifespan of the device. On the other hand, when using chemical vapor deposition (CVD) technology, the reactivity of each component during the reaction process is difficult to match precisely, which can easily lead to the coexistence of multiple phases (such as wurtzite phase, zincblende phase, etc.) inside the film. The electrical properties of different phases are significantly different, which can seriously damage the uniformity of the film's electrical properties, resulting in large fluctuations in device performance and low yield.
[0004] Atomic deposition technology can overcome the bottlenecks in the aforementioned fabrication techniques, enabling atomic-level precision control and the fabrication of thin films with high aspect ratios. However, in the growth of wurtzite ferroelectric thin films, atomic deposition technology still faces unique challenges: Firstly, the byproducts generated during the reaction are corrosive, damaging the substrate and reaction chamber, and may also undergo secondary reactions with the film, affecting its purity. Secondly, as the film grows, the active sites on the substrate surface are gradually consumed, leading to a decrease in surface activity and triggering a self-limiting growth phenomenon, where the growth rate drops sharply or even stops after the film reaches a certain thickness. This phenomenon directly leads to two problems: firstly, the film thickness is limited, failing to meet the requirements of some high-performance devices for thick films; secondly, the doping concentration is low and difficult to control, making it impossible to optimize the key properties of the film, such as ferroelectricity and dielectric properties, through precise doping. Furthermore, the slow growth rate significantly reduces fabrication efficiency and increases production costs.
[0005] Therefore, there is an urgent need to develop a method and process for controlling and preparing wurtzite ferroelectric materials that can overcome the self-limiting growth problem, so as to achieve control over doping concentration and growth thickness over a wide range, thereby promoting the development of high-performance and high-reliability wurtzite ferroelectric memory devices. Summary of the Invention
[0006] The purpose of this invention is to provide a self-limiting reaction-controlled atomic layer deposition method for wurtzite ferroelectric materials. This method forms nitride wurtzite materials by depositing AlN and BN thin films, and forms oxide wurtzite materials by depositing ZnO and MgO. This method removes the self-limiting growth of wurtzite ferroelectric materials and enables arbitrary doping concentration control and the growth of wurtzite ferroelectric thin films of arbitrary thickness, thereby achieving high-performance ferroelectric memory.
[0007] To achieve the above objectives, firstly, this technical solution provides a method for atomic layer deposition of wurtzite ferroelectric materials with self-limited reaction regulation, comprising the following steps:
[0008] S1: Deposit an AlN seed layer on the substrate using atomic layer deposition (ALD) technology; S2: Atomic layer deposition (ALD) is used to deposit a BN film on an AlN seed layer to obtain a group III nitride film; S3: Deposit AlN thin films using atomic layer deposition on group III nitride films.
[0009] This scheme removes the self-limiting growth of wurtzite ferroelectric materials by depositing AlN and BN films. The AlN seed layer provides initial active sites for the growth of the BN film, and then an AlN film is deposited on the BN film. Since the BN film is self-limiting and its growth rate slows down after reaching a certain thickness, this scheme grows an AlN film on the basis of the BN film to allow the BN film to continue growing.
[0010] Because this wurtzite ferroelectric material overcomes self-limiting growth, the thickness of the BN and AlN films can be varied to control the thickness of the wurtzite ferroelectric material, thus enabling the growth of wurtzite ferroelectric films of arbitrary thickness. Furthermore, the doping concentration can be controlled by flexibly adjusting the thickness ratio of the AlN and BN films.
[0011] In some embodiments, the BN film and the AlN film constitute a wurtzite ferroelectric film, and the thickness of the wurtzite ferroelectric film is the sum of the thicknesses of the BN film and the AlN film.
[0012] In some embodiments, the thickness of the wurtzite ferroelectric thin film is 20~200 nm.
[0013] That is, when it is necessary to control the thickness of the wurtzite ferroelectric thin film of the wurtzite ferroelectric material, the thickness of the BN film or AlN film is controlled.
[0014] In some embodiments, the thickness of the BN film is 1~10 nm, and the thickness of the AlN film is 9~190 nm.
[0015] In some embodiments, the doping concentration of the AlBN thin film is the ratio of the thickness of the BN thin film to the thickness of the wurtzite ferroelectric thin film.
[0016] In some embodiments, the doping concentration of the AlBN thin film is 0.5-50%.
[0017] That is, when it is necessary to control the doping concentration of AlBN thin films in wurtzite ferroelectric materials, the thickness of BN thin films or AlN can be controlled.
[0018] In other words, when it is necessary to obtain wurtzite ferroelectric materials with high doping concentration of AlBN film and thickness of wurtzite ferroelectric film, the thickness ratio of BN film is increased, thereby avoiding the problem of low film thickness and low doping concentration caused by atomic layer deposition technology due to the self-limiting nature of BN film.
[0019] In step S1, the substrate is a heterogeneous substrate, selected from sapphire substrate, SiC substrate, Si substrate, or Pt substrate.
[0020] In step S1, the thickness of the AlN seed layer is 10 mm.
[0021] In step S1, the substrate is placed on the sample stage, and the reaction chamber is evacuated to the specified pressure. Carrier gas is continuously introduced into the reaction chamber and the pipeline, and the preheating of the reaction chamber begins. After the reaction chamber and the precursor source bottle are preheated to the specified process temperature, the substrate is sent from the sample stage into the reaction chamber, and an AlN seed layer of a specified thickness is deposited on the surface of the substrate.
[0022] Step S1 of this scheme uses an AlN seed layer as the bottom layer, which can improve the interfacial adhesion of the wurtzite ferroelectric thin film and further enhance the film properties.
[0023] In some embodiments, the specified pressure is less than 0.5 Pa.
[0024] In some embodiments, the carrier gas is nitrogen or argon, the pipeline carrier gas flow rate is 10~50 sccm, and the chamber carrier gas flow rate is 200~500 sccm.
[0025] In some embodiments, the specified process temperature range for the reaction chamber is 200~400°C, and the specified process temperature range for the precursor source bottle is 20~150°C.
[0026] Secondly, this technical solution provides a self-limiting reaction-controlled atomic layer deposition method for wurtzite ferroelectric materials, comprising the following steps: S1: Deposit a ZnO seed layer on the substrate using atomic layer deposition (ALD) technology; S2: An oxide film is obtained by depositing an MgO thin film using atomic layer deposition on a ZnO seed layer; S3: Deposit ZnO thin films using atomic layer deposition (ALD) on oxide films.
[0027] Similarly, this scheme removes the self-limiting growth of wurtzite ferroelectric materials by depositing ZnO and MgO thin films. The ZnO seed layer provides initial active sites for the growth of the MgO thin film, and then a ZnO thin film is deposited on the MgO thin film. Since the MgO thin film is self-limiting, its growth rate slows down after it reaches a certain thickness. Therefore, this scheme grows a ZnO thin film on the basis of the MgO thin film.
[0028] Because this wurtzite ferroelectric material overcomes self-limiting growth, the thickness of the oxide wurtzite ferroelectric material can be controlled by altering the thicknesses of the ZnO and MgO films, thus enabling the growth of wurtzite ferroelectric films of arbitrary thickness. Furthermore, the doping concentration can be controlled by flexibly adjusting the thickness ratio of the ZnO and MgO films.
[0029] Because this wurtzite ferroelectric material overcomes self-limiting growth, the thickness of the ZnO and MgO films can be varied to control the thickness of the wurtzite ferroelectric material, thus enabling the growth of wurtzite ferroelectric films of arbitrary thickness. Furthermore, the doping concentration can be controlled by flexibly adjusting the thickness ratio of the ZnO and MgO films.
[0030] In some embodiments, the ZnO film and the MgO film constitute a wurtzite ferroelectric film, and the thickness of the wurtzite ferroelectric film is the sum of the thicknesses of the ZnO film and the MgO film.
[0031] In some embodiments, the thickness of the wurtzite ferroelectric thin film is 20~200 nm.
[0032] That is, when it is necessary to control the thickness of the wurtzite ferroelectric thin film of the wurtzite ferroelectric material, the thickness of the ZnO thin film and the MgO thin film are controlled.
[0033] In some embodiments, the thickness of the MgO film is 1~10 nm, and the thickness of the ZnO film is 9~190 nm.
[0034] In some embodiments, the doping concentration of the ZnMgO thin film is the ratio of the thickness of the MgO thin film to the thickness of the wurtzite ferroelectric thin film.
[0035] In some embodiments, the doping concentration of the ZnMgO thin film is 0.5~50%.
[0036] That is, when it is necessary to control the doping concentration of the ZnMgO thin film of wurtzite ferroelectric material, the thickness of the MgO thin film or ZnO can be controlled.
[0037] In other words, when a wurtzite ferroelectric material with a high doping concentration of ZnMgO thin film and a thickness of wurtzite ferroelectric thin film is required, increasing the thickness ratio of MgO thin film can avoid the problem of low film thickness and low doping concentration caused by the self-limiting nature of MgO thin film in atomic layer deposition technology.
[0038] In step S1, the substrate is a heterogeneous substrate, selected from sapphire substrate, SiC substrate, Si substrate, or Pt substrate.
[0039] In step S1, the thickness of the ZnO seed layer is 10 mm.
[0040] In step S1, the substrate is placed on the sample stage, and the reaction chamber is evacuated to the specified pressure. Carrier gas is continuously introduced into the reaction chamber and the pipeline, and the preheating of the reaction chamber begins. After the reaction chamber and the precursor source bottle are preheated to the specified process temperature, the substrate is sent from the sample stage into the reaction chamber, and a ZnO seed layer of specified thickness is deposited on the surface of the substrate.
[0041] Step S1 of this scheme uses a ZnO seed layer as the bottom layer, which can improve the interfacial adhesion of the wurtzite ferroelectric thin film and further enhance the film properties.
[0042] In some embodiments, the specified pressure is less than 0.5 Pa.
[0043] In some embodiments, the carrier gas is nitrogen or argon, the pipeline carrier gas flow rate is 10~50 sccm, and the chamber carrier gas flow rate is 200~500 sccm.
[0044] In some embodiments, the specified process temperature range for the reaction chamber is 200~400°C, and the specified process temperature range for the precursor source bottle is 20~150°C.
[0045] Thirdly, this solution provides a wurtzite ferroelectric material with self-limited reaction regulation, comprising: a substrate, an AlN seed layer, a BN film, and an AlN film from bottom to top, wherein the BN film and the AlN film constitute a wurtzite ferroelectric film.
[0046] In some embodiments, the thickness of the wurtzite ferroelectric thin film is 20~200 nm.
[0047] In some embodiments, the doping concentration of the AlBN thin film is the ratio of the thickness of the BN thin film to the thickness of the wurtzite ferroelectric thin film.
[0048] In some embodiments, the doping concentration of the AlBN thin film is 0.5-50%.
[0049] Fourthly, this solution provides a wurtzite ferroelectric material with self-limited reaction regulation, comprising: a substrate, a ZnO seed layer, a MgO thin film, and a ZnO thin film from bottom to top, wherein the MgO thin film and the ZnO thin film constitute a wurtzite ferroelectric thin film.
[0050] In some embodiments, the thickness of the wurtzite ferroelectric thin film is 20~200 nm.
[0051] In some embodiments, the doping concentration of the ZnMgO thin film is the ratio of the thickness of the BN thin film to the thickness of the wurtzite ferroelectric thin film.
[0052] In some embodiments, the doping concentration of the ZnMgO thin film is 0.5~50%.
[0053] Fifthly, this solution provides a ferroelectric memory that uses the aforementioned self-limiting reaction-regulated wurtzite ferroelectric material.
[0054] Compared with existing technologies, this technical solution has the following characteristics and beneficial effects: This method provides a self-restricted reaction-controlled atomic layer deposition method for wurtzite ferroelectric materials. By depositing BN and AlN films on an AlN seed layer and MgO and ZnO films on a ZnO seed layer, the self-restricted growth of wurtzite ferroelectric materials is removed. Furthermore, the doping concentrations of AlBN and ZnMgO films can be flexibly controlled, enabling the rapid fabrication of high-quality films with a wide range of growth thicknesses and doping concentrations. This method significantly improves the reliability of ferroelectric memory devices and the flexibility of material combinations and structural design. Attached Figure Description
[0055] Figure 1 This is a schematic diagram of the structure of the first aspect of the present invention for preparing wurtzite ferroelectric materials.
[0056] Figure 2 A diagram illustrating the preparation process of atomic layer deposition of wurtzite ferroelectric thin films containing nitrides.
[0057] Figure 3 This is a schematic diagram of the structure of the present invention for preparing wurtzite ferroelectric materials, which is the second aspect of the invention.
[0058] Figure 4 This diagram illustrates the preparation process of an atomic layer deposition (ALD) wurtzite ferroelectric thin film. Detailed Implementation
[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.
[0060] Example 1 1. Use sapphire as a substrate and place it on the sample stage. Evacuate the reaction chamber and then introduce nitrogen gas into the chamber as a carrier gas (pipe flow rate 30 sccm, chamber flow rate 400 sccm).
[0061] 2. Preheat the reaction chamber to 300 ℃ and the precursor source bottle to 100 ℃.
[0062] 3. An AlN seed layer with a thickness of 10 nm was deposited on the substrate surface using atomic layer deposition (ALD) technology to enhance interfacial adhesion.
[0063] 4. First, a 1 nm thick BN film is deposited. As BN grows, the surface active sites gradually passivate, and the growth rate begins to be limited. Then, a 19 nm thick AlN film is deposited on the BN film. Al atoms bind to the inert sites on the BN surface, breaking the self-limiting effect.
[0064] 5. Finally, an AlBN wurtzite ferroelectric thin film with a total thickness of 20 nm was obtained.
[0065] Example 2 1. Select silicon (Si) as the substrate and place it on the sample stage. Evacuate the reaction chamber and then introduce argon gas into the chamber as the carrier gas.
[0066] 2. Preheat the reaction chamber to 350 ℃, and preheat the precursor bottle at the same time.
[0067] 3. A 10 nm thick ZnO seed layer was deposited on the substrate surface using atomic layer deposition (ALD) technology to enhance interfacial adhesion.
[0068] 4. First, a 10 nm thick MgO film is deposited. As MgO grows, the surface active sites gradually passivate, and the growth rate begins to be limited. Then, a 10 nm thick ZnO film is deposited on the MgO film. Due to the introduction of ZnO, the surface passivated by MgO is continuously activated, enabling the film to break through the growth limit of a single material, continuously increase in thickness, and overcome the self-limiting effect.
[0069] 5. Finally, a ZnMgO wurtzite ferroelectric thin film with a total thickness of 200 nm was obtained.
[0070] Comparative Example 1 1. Using the same sapphire substrate and preheating conditions as in Example 1, and after depositing a 10 nm AlN seed layer, a 10 nm BN thin film was continuously deposited.
[0071] 2. Growth is normal in the early stage of deposition, but when the thickness of BN reaches about 2 nm, the growth rate drops sharply and gradually stops due to the surface active sites being covered or consumed by byproducts (self-limiting growth phenomenon).
[0072] 3. No matter how many deposition pulse cycles are added, the final film thickness is always difficult to exceed 5 nm, and the doping concentration cannot be controlled by adjusting the ratio.
[0073] Performance testing: The thickness of the products obtained from each embodiment and comparative example was tested. It can be seen that the thickness of the wurtzite ferroelectric material prepared in Example 1 is 20.06 nm with a doping concentration of 5%; the thickness of the wurtzite ferroelectric material prepared in Example 2 is 200.34 nm with a doping concentration of 50%. This proves that the experimental method of this scheme can indeed remove the self-limitation growth of wurtzite ferroelectric material and achieve arbitrary doping concentration control and arbitrary thickness wurtzite ferroelectric film growth.
[0074] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been 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.
[0075] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A method for atomic layer deposition of wurtzite ferroelectric materials with self-limiting reaction regulation, characterized in that, Includes the following steps: S1: Deposit an AlN seed layer on the substrate using atomic layer deposition (ALD) technology; S2: Atomic layer deposition (ALD) is used to deposit a BN film on an AlN seed layer to obtain a group III nitride film; S3: Deposit AlN thin films using atomic layer deposition on group III nitride films.
2. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limiting reaction regulation according to claim 1, characterized in that, BN and AlN films constitute a wurtzite ferroelectric film. The thickness of the wurtzite ferroelectric film is the sum of the thicknesses of the BN and AlN films. The thickness of the wurtzite ferroelectric film is 20~200nm, and the thickness of the BN film is 1~10nm.
3. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limited reaction regulation according to claim 1, characterized in that, The doping concentration of AlBN thin films is the ratio of the thickness of the BN thin film to the thickness of the wurtzite ferroelectric thin film, and the doping concentration of AlBN thin films ranges from 0.1% to 40%.
4. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limited reaction regulation according to claim 1, characterized in that, When it is necessary to control the doping concentration of AlBN thin films in wurtzite ferroelectric materials or to control the thickness of wurtzite ferroelectric thin films in wurtzite ferroelectric materials, the thickness of the BN film or AlN film is adjusted.
5. A method for atomic layer deposition of wurtzite ferroelectric materials with self-limiting reaction regulation, characterized in that, Includes the following steps: S1: Deposit a ZnO seed layer on the substrate using atomic layer deposition (ALD) technology; S2: An oxide film is obtained by depositing an MgO thin film using atomic layer deposition on a ZnO seed layer; S3: Deposit ZnO thin films using atomic layer deposition (ALD) on oxide films.
6. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limited reaction regulation according to claim 5, characterized in that, ZnO and MgO films constitute a wurtzite ferroelectric film. The thickness of the wurtzite ferroelectric film is the sum of the thicknesses of the ZnO and MgO films, and the thickness of the wurtzite ferroelectric film is 20~200 nm.
7. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limiting reaction regulation according to claim 5, characterized in that, The thickness of the MgO thin film is 1~10 nm.
8. The method for atomic layer deposition of wurtzite ferroelectric materials with self-limiting reaction regulation according to claim 1, characterized in that... When it is necessary to control the doping concentration of the ZnMgO thin film of the wurtzite ferroelectric material or to control the thickness of the wurtzite ferroelectric thin film, the thickness of the MgO thin film or ZnO thin film is adjusted.
9. A self-limited reaction-regulated wurtzite ferroelectric material, prepared by the atomic layer deposition method for self-limited reaction-regulated wurtzite ferroelectric materials according to any one of claims 1 to 5, characterized in that, include: From bottom to top: substrate, AlN seed layer, BN film, and AlN film, wherein the BN film and AlN film constitute a wurtzite ferroelectric thin film.
10. A self-limited reaction-regulated wurtzite ferroelectric material, prepared by the atomic layer deposition method for self-limited reaction-regulated wurtzite ferroelectric materials according to any one of claims 6 to 8, characterized in that, include: From bottom to top: substrate, ZnO seed layer, MgO thin film, and ZnO thin film, wherein the MgO thin film and ZnO thin film constitute a wurtzite ferroelectric thin film.