Ferroelectric thin film with two-dimensional layered electrodes and method of making the same

Abstract

The application provides a ferroelectric thin film with a two-dimensional layered electrode and a preparation method thereof. The ferroelectric thin film comprises a ferroelectric hafnium oxide thin film and a two-dimensional layered calcium nitride electrode arranged on the ferroelectric hafnium oxide thin film. The calcium nitride of the application has excellent in-plane lattice matching with hafnium oxide (111), and the lattice mismatch degree is extremely low, which is beneficial to realize high-quality epitaxial growth of the heterostructure and provides a structural basis for device manufacturing. The calcium nitride of the application can form stable chemical bonds (such as Hf-N and O-Ca) with hafnium oxide at the interface, can effectively enhance the interface bonding force, and improve the structural stability of the device. The calcium nitride of the application can significantly inhibit the depolarization field in the hafnium oxide thin film, restore and exceed the ferroelectric polarization intensity of the hafnium oxide bulk, and significantly improve the ferroelectric performance of the hafnium oxide.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor integrated circuit design and manufacturing, and particularly relates to a ferroelectric thin film with a two-dimensional layered electrode, a preparation method thereof, a ferroelectric device and an electronic equipment. BACKGROUND

[0002] In 2011, a hafnium-doped hafnium oxide (chemical formula: HfO2) thin film was first found to have ferroelectricity. Since it is highly compatible with silicon-based semiconductor processes and can still maintain stable ferroelectricity at the nanometer scale, HfO2 is widely considered to be one of the most promising materials for building a new generation of ferroelectric memories. Such memories have the advantages of fast read-write speed, low power consumption, high storage density and non-volatility, and are particularly suitable for the urgent needs of high-performance storage technology in the big data era.

[0003] Ferroelectric memories have been considered as an important candidate for the next generation of storage technology due to their non-volatility and high-speed response. However, traditional perovskite structure ferroelectric materials have poor compatibility with existing semiconductor processes and difficulty in size reduction, resulting in high manufacturing costs and limited integration density, which makes it difficult to meet the requirements of industrialization. In contrast, hafnium-based ferroelectric materials are highly compatible with mainstream CMOS processes, can still maintain strong residual polarization at nanometer size, and their preparation process has become mature, providing a new path and possibility for the development of ferroelectric memories.

[0004] However, the practical application of hafnium-based ferroelectric memories still faces many challenges, especially in terms of reliability. For example, existing hafnium-based ferroelectric memories have insufficient ferroelectric properties and high leakage current, which greatly reduces the stability and life of hafnium-based ferroelectric memories.

[0005] It should be noted that the above introduction to the technical background is only to facilitate a clear and complete description of the technical solutions of the present application, and to facilitate the understanding of those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art merely because they are described in the background section of the present application. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a ferroelectric thin film with a two-dimensional layered electrode, a preparation method thereof, a ferroelectric device and an electronic equipment, which solves the problem of insufficient reliability of hafnium-based ferroelectric materials in the prior art.

[0007] To achieve the above-mentioned purpose and other related purposes, the present application provides a ferroelectric thin film with a two-dimensional layered electrode, which comprises: a ferroelectric hafnium oxide thin film and a two-dimensional layered calcium nitride electrode disposed on the ferroelectric hafnium oxide thin film.

[0008] Optionally, the calcium nitride electrode is arranged in a manner that the calcium nitride electrode matches the hafnium oxide thin film in the (111) plane after being expanded by 2*2 supercell, and the lattice mismatch of the two after matching is less than 1%.

[0009] Optionally, the ferroelectric hafnium oxide thin film and the calcium nitride electrode alternately form stable chemical bonds between cations and anions at the interface, and the chemical bonds include Hf-N and O-Ca bonds.

[0010] Optionally, the material of the ferroelectric hafnium oxide thin film includes silicon-doped hafnium oxide, and the component of silicon ranges from 2.5 mole percent to 6 mole percent.

[0011] Optionally, the thickness of the ferroelectric hafnium oxide thin film ranges from 1 nm to 10 nm.

[0012] Optionally, the calcium nitride electrode is used to shield the depolarization field in the ferroelectric hafnium oxide thin film, and the depolarization field of the ferroelectric thin film with the two-dimensional layered electrode is less than 4 MV / cm.

[0013] Optionally, the polarization displacement of the ferroelectric thin film with the two-dimensional layered electrode is 0.0175 nm to 0.0195 nm, and the polarization intensity is 55 μC / cm² to 65 μC / cm².

[0014] The application also provides a preparation method of the ferroelectric thin film with the two-dimensional layered electrode, and the preparation method includes the following steps: forming the ferroelectric hafnium oxide thin film; and arranging the two-dimensional layered calcium nitride electrode on at least one surface of the ferroelectric hafnium oxide thin film.

[0015] Optionally, the ferroelectric hafnium oxide thin film is prepared by a metal organic atomic layer deposition process, and the precursors of the metal organic atomic layer deposition process include tetrakis(ethylmethylamino)hafnium, tetrakis(dimethylamino)silane, a metal organic compound and ozone.

[0016] Optionally, the two-dimensional layered calcium nitride electrode is formed on the surface of the ferroelectric hafnium oxide thin film by a physical vapor deposition process or a chemical vapor deposition process, and the ferroelectric hafnium oxide thin film and the calcium nitride electrode alternately form stable chemical bonds between cations and anions at the interface by an annealing process, and the chemical bonds include Hf-N and O-Ca bonds.

[0017] The application also provides a ferroelectric device, which includes the ferroelectric thin film with the two-dimensional layered electrode according to any one of the above embodiments.

[0018] Optionally, the ferroelectric device includes one of a ferroelectric random access memory, a ferroelectric field effect transistor, a ferroelectric tunnel junction, a capacitor and a piezoelectric sensor.

[0019] The application also provides an electronic device, which is integrated with the ferroelectric device according to any one of the above embodiments.

[0020] Optionally, the electronic device comprises one of a smart phone, a computer, a smart car, an Internet of Things terminal, an artificial intelligence chip and a smart robot.

[0021] As described above, the ferroelectric thin film with a two-dimensional layered electrode, the preparation method thereof, the ferroelectric device and the electronic device of the present application have the following beneficial effects:

[0022] The calcium nitride (Ca2N) of the present application has excellent lattice matching with hafnium oxide (HfO2), and the lattice mismatch degree is extremely low (less than 1%), which is beneficial to realize high-quality epitaxial growth of heterostructures and provides a structural basis for device manufacturing.

[0023] The calcium nitride (Ca2N) of the present application can form stable chemical bonds (such as Hf-N and O-Ca) at the interface with hafnium oxide (HfO2), which can effectively enhance the interface bonding force and improve the structural stability of the device.

[0024] The calcium nitride (Ca2N) of the present application can significantly inhibit the depolarization field in the hafnium oxide (HfO2) thin film, restore and exceed the ferroelectric polarization strength of the hafnium oxide bulk, and significantly improve the ferroelectric performance of hafnium oxide (HfO2).

[0025] The calcium nitride (Ca2N) of the present application has excellent structural matching and electrical properties with the hafnium oxide (HfO2) material system, is suitable for large-scale preparation of high-quality hafnium oxide (HfO2) ferroelectric thin films, and can be widely used in the development of new generation of non-volatile memories and ferroelectric electronic devices. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings included to provide a further understanding of the embodiments of the present application, constitute a part of the specification and serve to explain the principles of the present application together with the text. Obviously, the accompanying drawings in the following description are only some embodiments of the present application.

[0027] Figure 1 The crystal structure diagram of the ferroelectric hafnium oxide (HfO2) thin film of the embodiment of the present application is shown in the (111) crystal plane.

[0028] Figure 2 The crystal structure diagram of the calcium nitride (Ca2N) of the embodiment of the present application after (2x2) supercell expansion in the (0001) crystal plane is shown.

[0029] Figure 3 The matching structure diagram of the calcium nitride (Ca2N) of the embodiment of the present application after (2x2) supercell expansion in the (0001) crystal plane and the (111) crystal plane of the ferroelectric hafnium oxide (HfO2) thin film is shown.

[0030] Figure 4 Shown is the structure of the HfO2(111) thin film without electrode and the distribution of its electronic potential energy in the out-of-plane direction.

[0031] Figure 5 Shown is a ferroelectric hafnium oxide (HfO2) thin film structure with a two-dimensional layered calcium nitride (Ca2N) electrode and its electronic potential energy distribution according to an embodiment of the present invention.

[0032] Figure 6 Shown is the layered density of states (LDOS) of HfO2 thin film without electrodes.

[0033] Figure 7 The layered density of states (LDOS) of a ferroelectric hafnium oxide (HfO2) film with a two-dimensional layered calcium dicalcium nitride (Ca2N) electrode according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0036] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0037] For example, when describing the embodiments of the present invention, cross-sectional views of device structures may be partially enlarged to scale for ease of explanation. Furthermore, these schematic views are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual manufacturing, three-dimensional dimensions, including length, width, and depth, should be included.

[0038] For convenience in description, spatially relative terms such as "beneath", "below", "lower", "bottom", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a layer overlies another layer, it can be the case that the layer is the only layer between the two layers or that intervening layers are also present. Conversely, if a layer is disposed under another layer, it can be the case that the layer is the only layer between the two layers or that intervening layers are also present.

[0039] In the context of the present application, a structure described as having a first feature "on" a second feature can include embodiments in which the first and second features are formed in direct contact, as well as embodiments in which additional features are formed between the first and second features, such that the first and second features can not be in direct contact.

[0040] Needless to say, the diagrams provided in the embodiments only schematically illustrate the basic concept of the present application, and thus only the components related to the present application are shown in the diagrams, not the number, shape and size of the components when actually implemented. The shape, number and ratio of the components when actually implemented can be arbitrarily changed, and the layout pattern of the components can be more complicated.

[0041] The practical application of hafnium-based ferroelectric memory still faces many challenges, especially in terms of reliability. Among them, the selection of electrode material is considered to be a key factor affecting the further improvement of the ferroelectric performance of hafnium-based ferroelectric thin film. Optimizing the electrode material not only helps to enhance the ferroelectric performance and suppress the leakage current, but also improves the stability and life of the device.

[0042] As shown in Figures 1-3 The present embodiment provides a ferroelectric thin film with a two-dimensional layered electrode, which includes a ferroelectric hafnium oxide thin film and a two-dimensional layered calcium nitride (Ca2N) electrode disposed on the ferroelectric hafnium oxide (HfO2) thin film. The present application based on the results of density functional theory (DFT) calculations shows that calcium nitride (Ca2N) can effectively shield the depolarization field in the ferroelectric hafnium oxide (HfO2) thin film, thereby effectively enhancing the ferroelectric polarization performance of the ferroelectric hafnium oxide (HfO2) thin film.

[0043] In some embodiments, the material of the ferroelectric hafnium oxide thin film includes silicon-doped hafnium oxide, wherein the component of silicon ranges from 2.5 mole percent to 6 mole percent. The silicon-doped hafnium oxide (HfO2) thin film of the present embodiment has significant ferroelectric performance in the orthorhombic phase structure, with a remanent polarization of more than 10 μC / cm 2, the coercive field is about 1 MV / cm, and the piezoelectric response is good. The silicon-doped hafnium oxide (HfO2) film of the embodiment is highly compatible with silicon-based processes, and has broad application prospects in ferroelectric field effect transistors (FeFET) and capacitors.

[0044] In some embodiments, the thickness of the ferroelectric hafnium oxide film ranges from 1 nm to 10 nm. The silicon-doped hafnium oxide (HfO2) film of the embodiment remains stable ferroelectricity when the thickness is reduced to 1 nm, and the polarity distortion of the silicon-doped hafnium oxide (HfO2) film is enhanced as the thickness decreases. Compared with the unstable behavior of the ferroelectricity of the perovskite ferroelectric material at a small thickness, the silicon-doped hafnium oxide (HfO2) film of the embodiment can work normally or abnormally at a smaller thickness. For example, when the silicon-doped hafnium oxide (HfO2) film is applied to a ferroelectric memory and an advanced transistor, the density of the ferroelectric memory and the advanced transistor can be greatly improved.

[0045] In some embodiments, the electrons of the calcium nitride (Ca2N) of the embodiment are mainly distributed in the interlayer space, have anisotropic low work function, and the electrons are weakly bound. Therefore, the calcium nitride (Ca2N) of the embodiment has two-dimensional electron transport characteristics, has high electron mobility, long average scattering time and average free path.

[0046] Figure 1 A crystal structure diagram of the ferroelectric hafnium oxide (HfO2) film of the embodiment on the (111) crystal plane is shown. Figure 2 A crystal structure diagram of the calcium nitride (Ca2N) of the embodiment expanded by a (2x2) supercell in the (0001) crystal plane is shown. Figure 3 A matching structure diagram of the (0001) crystal plane lattice of the calcium nitride (Ca2N) of the embodiment expanded by a (2x2) supercell and the (111) crystal plane lattice of the ferroelectric hafnium oxide (HfO2) film is shown as follows: Figure 3 In the embodiment, the calcium nitride electrode is arranged in such a manner that the (0001) plane of the calcium nitride (Ca2N) electrode expanded by a 2x2 supercell matches the (111) plane of the ferroelectric hafnium oxide (HfO2) film, and the lattice mismatch degree after the matching is less than 1%. The ferroelectric hafnium oxide (HfO2) film and the calcium nitride (Ca2N) electrode alternately form stable chemical bonds between cations and anions at the interface. The O atom of HfO2 and the Ca atom of Ca2N form an O-Ca bond at the interface, and the Hf atom and the N atom form an Hf-N bond, which has good structural compatibility and interface stability, and helps to form a stable heterostructure.

[0047] In some embodiments, the Ca2N electrode can be matched to one surface of the ferroelectric hafnium oxide (HfO2) film. In another embodiment, the Ca2N electrode can be matched to both surfaces of the ferroelectric hafnium oxide (HfO2) film, which can be matched according to the actual application scenario of the ferroelectric film. For example, when the ferroelectric film is used in a ferroelectric field effect transistor, the Ca2N electrode can be matched to only the upper surface of the ferroelectric hafnium oxide (HfO2) film; when the ferroelectric film is used in a capacitor, the Ca2N electrode can be matched to both the upper surface and the lower surface of the ferroelectric hafnium oxide (HfO2) film.

[0048] In some embodiments, the ferroelectric hafnium oxide (HfO2) film with a two-dimensional layered Ca2N electrode can further be provided with a metal electrode or a protective material on the Ca2N electrode in actual application, so as to prevent oxidation of the Ca2N electrode and further improve the long-term stability of the device.

[0049] In some embodiments, the Ca2N electrode is used to shield the depolarization field in the ferroelectric hafnium oxide film. The depolarization field of the ferroelectric film with a two-dimensional layered electrode is less than 4 MV / cm, the polarization displacement of the ferroelectric film with a two-dimensional layered electrode is 0.0175 nm to 0.0195 nm, and the polarization intensity is 55 μC / cm2to 65 μC / cm2.

[0050] Figure 4 and Figure 5 The depolarization field in the HfO2 film without an electrode and the ferroelectric hafnium oxide (HfO2) film with a two-dimensional layered Ca2N electrode is shown. Figure 4 The HfO2(111) film structure without an electrode and the distribution of its electronic potential energy in the out-of-plane direction are shown. Figure 5 The ferroelectric hafnium oxide (HfO2) film structure with a two-dimensional layered Ca2N electrode and the distribution of its electronic potential energy are shown. The dashed line represents the average potential energy distribution obtained after smoothing treatment with the HfO2 interlayer spacing as the window. By calculating the electronic potential energy distribution in the HfO2 film without an electrode and the ferroelectric hafnium oxide (HfO2) film (HfO2 / Ca2N interface structure) with a two-dimensional layered Ca2N electrode, it is shown that there is a significant depolarization field in the HfO2(111) film without an electrode, and the depolarization field ε d is 16.1 MV / cm, as shown in Figure 4 ; and under the shielding effect of the Ca2N electrode, the depolarization field is significantly suppressed, and the depolarization field ε d is greatly reduced to -3.9 MV / cm, as shown in Figure 5 .

[0051] Figure 6 and Figure 7 Layered density of states (LDOS) of HfO2 thin film without electrode and ferroelectric hafnium oxide (HfO2) thin film with two-dimensional layered calcium nitride (Ca2N) electrode, respectively. It is shown in the layered density of states (LDOS) curves that, compared with HfO2 thin film without electrode (as shown in Figure 6 ), Ca2N material provides abundant low work function electrons in the HfO2 / Ca2N interface structure (as shown in Figure 7 ), which promotes the rearrangement and shielding effect of interface electrons, thus helping to stabilize the ferroelectric polarization.

[0052] Table 1

[0053]

[0054] Table 1 summarizes the polarization displacement, estimated polarization strength and depolarization field values of HfO2 (HfO2 bulk, HfO2 thin film without electrode and ferroelectric hafnium oxide (HfO2) thin film with two-dimensional layered calcium nitride (Ca2N) electrode, respectively). The results show that, first, the polarization displacement of HfO2 thin film without electrode decreases significantly under the condition of no shielding, and the polarization displacement is only 0.0054 nm, while under the shielding effect of Ca2N electrode, the polarization displacement (0.0185 nm) of ferroelectric hafnium oxide (HfO2) thin film with two-dimensional layered calcium nitride (Ca2N) electrode is even higher than that of HfO2 bulk (0.0158 nm); second, the polarization strength (59.0 μC / cm 2 ) of ferroelectric hafnium oxide (HfO2) thin film with two-dimensional layered calcium nitride (Ca2N) electrode not only far exceeds the polarization strength (17.2 μC / cm 2 ) of HfO2 thin film without electrode, but also exceeds the polarization strength (50.4 μC / cm 2 ) of HfO2 bulk, proving that calcium nitride (Ca2N) electrode has an enhancing effect on the polarization strength of ferroelectric hafnium oxide (HfO2) thin film; third, there is a significant depolarization field in HfO2 (111) thin film without electrode, and the depolarization field ε d is 16.1 MV / cm, as shown in Figure 4 ; while under the shielding effect of calcium nitride (Ca2N) electrode, the depolarization field is significantly inhibited, and the depolarization field ε d greatly reduces to -3.9 MV / cm, indicating that calcium nitride (Ca2N) electrode has a good shielding effect on the depolarization field of ferroelectric hafnium oxide (HfO2) thin film.

[0055] AsFigure 3 As shown, the embodiment also provides a method for preparing a ferroelectric hafnium oxide thin film with a two-dimensional layered electrode, the method comprising the steps of:

[0056] First, step 1) is performed to form a ferroelectric hafnium oxide thin film.

[0057] In some embodiments, the ferroelectric hafnium oxide thin film can be formed on a bulk substrate, which can be a silicon (Si) substrate, a germanium (Ge) substrate, a silicon germanium (SiGe) substrate, a silicon germanium carbon (SiGeC) substrate, a silicon carbide (SiC) substrate, a gallium arsenide (GaAs) substrate, an indium arsenide (InAs) substrate, an indium phosphide (InP) substrate, or other III / V semiconductor substrate or II / VI semiconductor substrate. Alternatively, the substrate can be a layered substrate including, for example, Si / SiGe, Si / SiC, silicon-on-insulator (SOI), or silicon germanium on insulator.

[0058] In some embodiments, the material of the ferroelectric hafnium oxide thin film includes silicon-doped hafnium oxide, where the silicon component ranges from 2.5 mole percent to 6 mole percent. In this embodiment, the ferroelectric hafnium oxide thin film can be prepared using a metal organic atomic layer deposition process (ALD), where the precursors of the metal organic atomic layer deposition process include tetrakis(ethylmethylamino)hafnium (TEMA-Hf), tetrakis(dimethylamino)silane (4DMAS), a metal organic compound, and ozone. By controlling the ratio of tetrakis(ethylmethylamino)hafnium (TEMA-Hf) and tetrakis(dimethylamino)silane (4DMAS), the silicon content of the ferroelectric hafnium oxide thin film can be adjusted.

[0059] Then, step 2) is performed to dispose a two-dimensional layered calcium nitride electrode on at least one surface of the ferroelectric hafnium oxide thin film.

[0060] In some embodiments, the two-dimensional layered calcium nitride electrode can be formed on the surface of the ferroelectric hafnium oxide thin film by a physical vapor deposition process or a chemical vapor deposition process, and an annealing process is performed to form stable chemical bonds between cations and anions at the interface of the ferroelectric hafnium oxide thin film and the calcium nitride electrode, including Hf-N and O-Ca bonds.

[0061] In one specific example, the preparation of the calcium nitride (Ca2N) electrode includes: mixing Ca3N2 powder and metallic calcium at a ratio of 1:1, pressing into a sheet, wrapping in a molybdenum foil, and annealing in a vacuum (<10 −3The sample is annealed at 800℃ for 48 hours under the condition of P a), and is processed by connecting a vacuum pump to the quartz tube and placing it in a box furnace. After annealing, it is rapidly quenched in water to inhibit intermediate reactions and avoid the formation of side phases. The obtained sample is ground into powder and can be re-annealed under the same conditions as above to improve uniformity, and finally form uniform calcium nitride (Ca2N). The prepared calcium nitride (Ca2N) can be formed on a ferroelectric hafnium oxide (HfO2) thin film by processes such as transfer process, sputtering process, evaporation process, etc., and the ferroelectric hafnium oxide thin film and calcium nitride electrode are made to form stable chemical bonds between cations and anions at the interface through processes such as annealing, etc. The above processes are preferably carried out in a vacuum or protective atmosphere to avoid oxidation of the calcium nitride (Ca2N).

[0062] The embodiment also provides a ferroelectric device including the ferroelectric thin film with a two-dimensional layered electrode according to any one of the above aspects.

[0063] In some embodiments, the ferroelectric device includes one of a ferroelectric random access memory (FeRAM), a ferroelectric field effect transistor (FeFFT), a ferroelectric tunnel junction (FTJ), a capacitor and a piezoelectric sensor.

[0064] The embodiment also provides an electronic device integrated with the ferroelectric device according to any one of the above aspects.

[0065] In some embodiments, the electronic device includes one of a smartphone, a computer, a smart car, an Internet of Things terminal, an artificial intelligence chip and a smart robot.

[0066] As described above, the ferroelectric thin film with a two-dimensional layered electrode, the preparation method thereof, the ferroelectric device and the electronic device of the present application have the following beneficial effects:

[0067] The calcium nitride (Ca2N) of the present application has excellent lattice matching with the (111) plane of hafnium oxide (HfO2), and the lattice mismatch is extremely low (less than 1%), which is conducive to the high-quality epitaxial growth of the heterostructure and provides a structural basis for device manufacturing.

[0068] The calcium nitride (Ca2N) of the present application can form stable chemical bonds (such as Hf-N and O-Ca) at the interface with hafnium oxide (HfO2), which can effectively enhance the interface bonding force and improve the structural stability of the device.

[0069] The calcium nitride (Ca2N) of the present application can significantly inhibit the depolarization field in the hafnium oxide (HfO2) thin film, restore and exceed the ferroelectric polarization intensity of the hafnium oxide bulk, and significantly improve the ferroelectric performance of the hafnium oxide (HfO2).

[0070] The calcium nitride (Ca2N) of the application has excellent structural matching and electrical performance with the hafnium oxide (HfO2) material system, is suitable for large-scale preparation of high-quality hafnium oxide (HfO2) ferroelectric thin film, and can be widely applied to development of a new generation of nonvolatile memory and ferroelectric electronic devices.

[0071] Therefore, the application effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0072] The above examples only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A ferroelectric thin film having a two-dimensional layered electrode, characterized by, The ferroelectric thin film comprises: The ferroelectric thin film comprises:

2. The ferroelectric thin film having a two-dimensional layered electrode according to claim 1, characterized by: The calcium nitride electrode is arranged in a manner that the calcium nitride electrode matches the ferroelectric hafnium oxide thin film in the (111) plane after being expanded by 2*2 supercell, and the lattice mismatch degree after matching is less than 1%.

3. The ferroelectric thin film with two-dimensional layered electrodes according to claim 1, characterized in that: The ferroelectric hafnium oxide thin film and the calcium nitride electrode alternately form stable chemical bonds between cations and anions at the interface, and the chemical bonds include Hf-N and O-Ca bonds.

4. The ferroelectric thin film with two-dimensional layered electrodes according to claim 1, characterized in that: The material of the ferroelectric hafnium oxide thin film comprises silicon-doped hafnium oxide, wherein the component range of silicon is 2.5 mole percent to 6 mole percent.

5. The ferroelectric thin film with two-dimensional layered electrodes according to claim 1, characterized in that: The thickness of the ferroelectric hafnium oxide thin film ranges from 1 nm to 10 nm.

6. The ferroelectric thin film with two-dimensional layered electrodes according to claim 1, characterized in that: The calcium nitride electrode is used to shield the depolarization field in the ferroelectric hafnium oxide thin film, and the depolarization field of the ferroelectric thin film with the two-dimensional layered electrode is less than 4 MV / cm.

7. The ferroelectric thin film with two-dimensional layered electrodes according to claim 1, characterized in that: The polarization displacement of the ferroelectric thin film with the two-dimensional layered electrode is 0.0175 nm to 0.0195 nm, and the polarization intensity is 55 μC / cm² to 65 μC / cm².

8. A method for producing a ferroelectric thin film having a two-dimensional layered electrode as claimed in any one of claims 1 to 7, characterized by, The preparation method comprises: forming a ferroelectric hafnium oxide thin film; arranging a two-dimensional layered calcium nitride electrode on at least one surface of the ferroelectric hafnium oxide thin film.

9. The method of claim 8, wherein the method further comprises: The ferroelectric hafnium oxide thin film is prepared by a metal organic atomic layer deposition process, wherein the precursors of the metal organic atomic layer deposition process comprise tetrakis(ethylmethylamino)hafnium, tetrakis(dimethylamino)silane, a metal organic compound and ozone.

10. The method of claim 8, wherein the method further comprises: The two-dimensional layered calcium nitride electrode is formed on the surface of the ferroelectric hafnium oxide thin film by a physical vapor deposition process or a chemical vapor deposition process, and the ferroelectric hafnium oxide thin film and the calcium nitride electrode alternately form stable chemical bonds between cations and anions at the interface by an annealing process, and the chemical bonds include Hf-N and O-Ca bonds. ​ 11. A ferroelectric device, characterized by, The ferroelectric device comprises the ferroelectric thin film with the two-dimensional layered electrode according to any one of claims 1-7.

12. The ferroelectric device of claim 11, wherein, The ferroelectric device comprises one of a ferroelectric random access memory, a ferroelectric field effect transistor, a ferroelectric tunnel junction, a capacitor and a piezoelectric sensor.

13. An electronic device, comprising: The electronic equipment integrates the ferroelectric device according to any one of claims 11-12.

14. The electronic device of claim 13, wherein: The electronic equipment comprises one of a smart phone, a computer, a smart car, an Internet of Things terminal, an artificial intelligence chip and a smart robot.

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