Superlattice ferroelectric enhancement structure in hafnium oxide-based thin film, preparation method and application of superlattice ferroelectric enhancement structure

Abstract

The invention relates to a superlattice ferroelectric enhancement structure in a hafnium oxide-based film as well as a preparation method and application thereof, and aims to realize remarkable improvement of ferroelectric properties of a hafnium oxide-doped film by stabilizing a ferroelectric orthogonal phase. The superlattice structure of the doped hafnium oxide thin film comprises bottom electrode layers and doped hafnium oxide thin film layers, wherein the bottom electrode layers are sequentially arranged in the direction perpendicular to the substrate, and the doped hafnium oxide thin film layers are alternately stacked. The superlattice interface engineering prepared through the atomic layer deposition or magnetron sputtering technology can effectively inhibit generation of non-ferroelectric phases (such as a monoclinic phase and a tetragonal phase), so that ferroelectric remanent polarization is remarkably enhanced. According to the doped hafnium oxide thin film device based on the superlattice structure, the voltage difference in the polarization inversion period can be enhanced, the state distinguishing in the reading operation period can be improved, the reading error rate can be reduced, the charge density stored in the unit area can be increased, the device size can be reduced, and the device performance can be improved. Therefore, the integration density and the storage density of the ferroelectric-based memory are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, a preparation method and applications thereof. Background Art

[0002] Hafnium oxide-based thin films have become a highly sought-after candidate for next-generation ferroelectric electronic devices due to their strong ferroelectricity at small sizes, compatibility with complementary metal oxide semiconductor (CMOS) technology, and high-temperature stability. The ferroelectric behavior of hafnium oxide-based materials is closely related to their crystal structure. Both the orthorhombic phase (space group Pca21) and the rhombohedral phase (space group R3 / R3m) exhibit ferroelectricity due to their non-centrosymmetric properties.

[0003] However, the thermodynamic metastable nature of the orthorhombic and rhombohedral phases poses significant challenges to their stability in thin films. Doping with specific elements (such as zirconium, yttrium, and aluminum) has been shown to stabilize the ferroelectric orthorhombic phase and enhance ferroelectric properties. However, as the film thickness increases, non-ferroelectric phases (such as tetragonal or monoclinic phases) may coexist with the ferroelectric phase, resulting in a decrease in overall performance. Therefore, developing new methods to stabilize the orthorhombic / rhombohedral phases and enhance ferroelectric properties while maintaining compatibility with CMOS processes is key to promoting the development of high-performance ferroelectric memories and electronic devices. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, a preparation method and application thereof, so as to solve the problems in the background technology.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0006] On the one hand, the present invention provides a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, comprising a bottom electrode layer, a doped hafnium oxide thin film layer A, and a doped hafnium oxide thin film layer B arranged in sequence in a direction perpendicular to a substrate, wherein the doped hafnium oxide thin film layer A and the doped hafnium oxide thin film layer B are in an alternating stacking structure, and a doped hafnium oxide thin film stop layer A and a doped hafnium oxide thin film stop layer B;

[0007] The first doped hafnium oxide thin film layer A is doped with hafnium metal oxide (Hf x A 1-x O2), the second layer of the doped hafnium oxide thin film layer B is doped with hafnium metal oxide (Hf x B 1-x O2);

[0008] The element A or the element B includes a group consisting of zirconium (Zr), silicon (Si), lanthanum (La), aluminum (Al), yttrium (Y), gadolinium (Gd), strontium (Sr), manganese (Mn), and cerium (Ce), and is not the same element; the range of x is 0.5 to 0.99.

[0009] As a further technical solution of the present invention: each of the doped hafnium oxide thin film layers A has a thickness of at least 0.5 nm.

[0010] As a further technical solution of the present invention: each of the doped hafnium oxide thin film layers B has a thickness of at least 0.5 nm.

[0011] On the other hand, the present invention also provides a method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, comprising the following steps:

[0012] providing a substrate;

[0013] forming a bottom electrode layer on the substrate;

[0014] A superlattice structure is grown layer by layer on the bottom electrode layer, wherein the growth steps are alternated between a first hafnium oxide doped thin film layer A and a second hafnium oxide doped thin film layer B, thereby providing a stable ferroelectric phase within the superlattice structure.

[0015] As a further technical solution of the present invention: wherein the substrate is one of SrTiO3, Nb-SrTiO3, LSAT, DyScO3, NdScO3, TbScO3, LaAlO3, NdGaO3, YAlO3, SrLaAlO4 or Si, Si / SiO2.

[0016] As a further technical solution of the present invention: wherein the substrate is an oriented single crystal substrate.

[0017] As a further technical solution of the present invention: wherein the growth step is performed by pulsed laser deposition (PLD), magnetron sputtering, atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0018] As a further technical solution of the present invention: for the pulsed laser deposition method, the pulsed layer deposition is performed at about 800° C. using an excimer laser with a wavelength of 248 nm.

[0019] On the other hand, the present invention also provides a ferroelectric random access memory cell, comprising a top electrode layer, an oriented single crystal substrate, a superlattice ferroelectric enhancement structure of the above-mentioned doped hafnium oxide superlattice film, and a bottom electrode layer.

[0020] On the other hand, the present invention further provides a ferroelectric field effect transistor unit, comprising a gate electrode layer, an interface layer and the above-mentioned superlattice ferroelectric enhancement structure of the doped hafnium oxide superlattice film.

[0021] In summary, the present invention includes at least one of the following beneficial technical effects:

[0022] 1. This invention discloses a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, its preparation method, and its application. The hafnium oxide-based thin film used in the superlattice structure is non-volatile and non-toxic, while traditional ferroelectric materials such as Pb(Zr,Ti)O3, SrBi2Ta2O9, and BiFeO3 are toxic or volatile. This makes the hafnium oxide-based superlattice thin film provided by the invention a safer and more environmentally friendly option.

[0023] 2. The hafnium oxide-based superlattice film provided by the present invention exhibits stable ferroelectricity and a large remanent polarization value even when the film thickness is reduced to approximately 10 nm. This is advantageous compared to traditional ferroelectric materials, which typically require film thicknesses greater than 50-100 nm to maintain robust ferroelectricity. Achieving robust ferroelectricity at smaller film thicknesses enables the design and manufacture of ferroelectric random access memory and ferroelectric field-effect transistor devices with higher density and greater integration capabilities.

[0024] 3. Compared to some traditional ferroelectric materials, the hafnium oxide-based superlattice films provided by the present invention have better durability and retention characteristics. They can withstand a large number of read and write cycles without significant performance degradation, making the stored data stable over long periods of time and ensuring long-term reliable retention.

[0025] 4. The hafnium oxide-based superlattice thin film provided by this invention can be used to manufacture ferroelectric random access memory (FRAM) and ferroelectric field-effect transistor (FFET) devices using standard CMOS processes, making them highly compatible with existing semiconductor manufacturing technologies. This compatibility simplifies the integration of FRAM and FFET cells into existing memory architectures, facilitating efficient large-scale production.

[0026] 5. The present invention provides a highly compatible and simple solution for improving the ferroelectric properties of hafnium oxide-based thin films, and provides a new approach for promoting the design of high-performance ferroelectric hafnium oxide-based electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the technical solutions in this embodiment, the following briefly introduces the drawings required for describing the embodiment and provides effective test data for this embodiment. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0028] Figure 1 Schematic diagram of the structure of a hafnium oxide-based superlattice film provided in this embodiment;

[0029] Figure 2 This is a flow chart of a method for preparing a hafnium oxide-based superlattice thin film provided in this embodiment;

[0030] Figure 3 1 is an X-ray diffraction (XRD) characterization result diagram of a hafnium oxide-based superlattice film and a single-layer zirconium-doped hafnium oxide film provided in this embodiment;

[0031] Table 1 lists the thickness, full width at half maximum of the rocking curve, and remanent polarization test results of a hafnium oxide-based superlattice film and a single-layer zirconium-doped hafnium oxide film provided in this embodiment;

[0032] Figure 4 is a graph showing the cycle durability test results of a hafnium oxide-based superlattice film provided in this embodiment;

[0033] Figure 5 is a graph showing the hysteresis loop test results of another hafnium oxide-based superlattice film provided in this embodiment;

[0034] Figure 6 This is a schematic diagram of the structure of a ferroelectric random access memory provided by this embodiment;

[0035] Figure 7 This is a schematic diagram of the structure of a ferroelectric field effect transistor provided in this embodiment.

[0036] Figure numerals: 10, substrate; 20, bottom electrode layer; 30, doped hafnium oxide thin film layer A; 40, doped hafnium oxide thin film layer B; 50, alternating stacking structure; 60, doped hafnium oxide thin film termination layer A; 70, doped hafnium oxide thin film termination layer B. DETAILED DESCRIPTION

[0037] The technical solution in this embodiment will be clearly and completely described below in conjunction with the drawings in this embodiment; it is obvious that the described embodiment is only a part of the embodiments of this application, not all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments in this application without making creative work are within the scope of protection of this application.

[0038] The accompanying drawings illustrate various structural schematics according to the present embodiment. These drawings are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positions, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0039] The terms used in this application are intended solely to describe specific embodiments and are not intended to limit this application. Terms such as "comprise," "include," and the like, used in this application indicate the presence of a feature, step, operation, and / or component, but do not preclude the presence or addition of one or more other features, steps, operations, or components. The term "layer," as used in this application, refers to a portion of material comprising a region having a thickness. A layer may extend horizontally, vertically, and / or along a tapered surface.

[0040] The terms "first", "second", etc. (if any) in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. It should be understood that the "plurality" mentioned in this article refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0041] The discovery of ferroelectricity in doped hafnium oxide thin films has paved the way for advanced electronic applications. Its excellent CMOS process compatibility and good scalability make it a promising candidate for next-generation ferroelectric electronic devices. Of particular note, hafnium oxide-based films exhibit an inverse size effect—their ferroelectric properties not only enhance but also become more stable as thickness decreases. This property holds great potential for a wide range of applications, including ferroelectric random access memory (FeRAM), ferroelectric tunneling junctions (FTJs), ferroelectric field-effect transistors (FeFETs), and neuromorphic computing. Achieving high remanent polarization in hafnium oxide-based films is key to improving the performance of ferroelectric devices, particularly data retention and long-term reliability. High remanent polarization not only increases the charge density per unit area, thereby increasing storage density and enabling smaller device sizes, but also enhances the polarization reversal voltage in non-volatile memory devices such as FeFETs. This significantly improves state differentiation during read operations and reduces read error rates.

[0042] Although hafnium oxide films exhibit good ferroelectric properties, achieving high remanent polarization in thin films remains a challenge. Ferroelectric phases (orthorhombic and rhombohedral phases) are typically in a thermodynamically metastable state, while non-ferroelectric phases (such as monoclinic and tetragonal phases) are easily formed under conventional preparation conditions, resulting in limited overall ferroelectric performance of the film. Based on this, the present application proposes a superlattice structure of a hafnium oxide-doped thin film that can effectively stabilize the ferroelectric orthorhombic phase and significantly increase the ferroelectric remanent polarization value, thereby enhancing the stability and reliability of ferroelectric memory.

[0043] Example 1:

[0044] like Figure 1 As shown, an embodiment of the present application provides a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, a preparation method, and its application. The superlattice ferroelectric enhancement structure includes a bottom electrode layer 20, a doped hafnium oxide thin film layer A30, a doped hafnium oxide thin film layer B40, and an alternating stacking structure 50 of the doped hafnium oxide thin film layer A30 and the doped hafnium oxide thin film layer B40, arranged in sequence perpendicular to the substrate 10. The number of alternating stackings determines the thickness of the hafnium oxide-based superlattice thin film. The hafnium oxide-based superlattice thin film structure is terminated by the doped hafnium oxide thin film layer A60 and the doped hafnium oxide thin film layer B70.

[0045] Next, each layer included in the hafnium oxide-based superlattice thin film structure is introduced separately.

[0046] In one possible implementation, the material of the bottom electrode layer 20 is a conductive oxide material having a perovskite structure, and the lattice parameter is range, matching with the substrate 10, and providing epitaxial stress.

[0047] In an exemplary embodiment, the conductive oxide material having a perovskite structure is La 1-x Sr x MnO3, LaNiO3, SrRuO3, Ba 1-x La x SnO3. Where x represents the atomic number ratio (0 <x<1)。

[0048] The thickness of the bottom electrode layer 20 can be flexibly adjusted according to needs. In one possible implementation, the thickness of the bottom electrode layer 20 is in the range of 5-30 nm, which is conducive to maintaining epitaxial stress transmission while maintaining electrical conductivity.

[0049] In one possible implementation, the material of the hafnium oxide doped thin film layer A30 and the hafnium oxide doped thin film layer B40 is a ferroelectric hafnium oxide doped material having spontaneous electric polarization function and electric polarization reversal function.

[0050] In an exemplary embodiment, the doped hafnium oxide material having ferroelectricity includes Hf 0.5 Zr 0.5 O2 and Hf 0.95 La 0.05 O2. Here, Hf refers to hafnium, Zr refers to zirconium, La refers to lanthanum, and O refers to oxygen. 0.5 Zr 0.5 O2 and Hf 0.95 La 0.05 The numbers in O2 represent the atomic number ratio.

[0051] The thickness of the hafnium oxide-doped thin film layer A30 and the hafnium oxide-doped thin film layer B40 can be flexibly adjusted as needed. In one possible implementation, the thickness of the hafnium oxide-doped thin film layer A30 and the hafnium oxide-doped thin film layer B40 ranges from 0.5 nm to 2.5 nm. This thickness is conducive to obtaining a stable ferroelectric phase in the hafnium oxide-doped superlattice thin film.

[0052] See also Figure 2 The method for preparing a hafnium oxide-doped superlattice thin film structure includes the following steps 201 to 205.

[0053] Step 201: providing a substrate.

[0054] The substrate 10 is a structure for supporting a doped hafnium oxide superlattice thin film. For example, the substrate 10 may include only a substrate, or may include a substrate and one or more film layers prepared on the substrate.

[0055] Exemplarily, the type of substrate may be an insulator substrate, a semiconductor substrate, a conductor substrate, etc. Among them, the insulator substrate may include a quartz substrate, a sapphire substrate, an insulating oxide substrate, etc. The semiconductor substrate may include a semiconductor substrate made of silicon, or silicon nitride, platinum-coated silicon, or a CMOS substrate, etc. The conductor substrate may include a metal substrate, a conductive oxide substrate, an alloy substrate, etc. In some embodiments, the substrate may also be a flexible substrate, for example, a polyimide (PI) substrate, a polyethylene terephthalate (PET) substrate, or a surface-treated polymer soft film substrate, etc. In some embodiments, the substrate may also be referred to as a wafer.

[0056] Step 202 : forming a bottom electrode layer 20 on the substrate 10 .

[0057] In the doped hafnium oxide superlattice thin film structure of the present application, the bottom electrode layer 20 is located on and in contact with the substrate 10. Therefore, after obtaining the substrate 10, the bottom electrode layer 20 is formed on the substrate 10. For example, the bottom electrode layer 20 can be formed on the substrate 10 by any thin film formation method (e.g., magnetron sputtering, evaporation, chemical vapor deposition, physical vapor deposition, or atomic layer deposition).

[0058] For example, according to the introduction of the bottom electrode layer 20 in the above embodiment, the material of the bottom electrode layer 20 may be La 1-x Sr x MnO3, LaNiO3, SrRuO3, Ba 1-x La x SnO3, etc., can be formed by directly depositing the corresponding materials.

[0059] Step 203 : forming a doped hafnium oxide thin film layer A30 on the bottom electrode layer 20 .

[0060] In the doped hafnium oxide superlattice thin film structure in the present application, the doped hafnium oxide thin film layer A30 is located on the side of the bottom electrode layer 20 away from the substrate 10 and is in contact with the bottom electrode layer 20. Therefore, after the bottom electrode layer 20 is formed, the doped hafnium oxide thin film layer A30 is formed on the bottom electrode layer 20.

[0061] For example, a doped hafnium oxide-based material (such as Hf) having ferroelectricity is deposited on the bottom electrode layer 20 by any thin film forming method (such as magnetron sputtering, evaporation, chemical vapor deposition, physical vapor deposition or atomic layer deposition). x Zr 1-x O2、Hfx Si 1-x O2、Hf x La 1-x O2、Hf x Al 1-x O2、Hf x Y 1-x O2, etc.) to form a doped hafnium oxide thin film layer A30.

[0062] Step 204 : forming a hafnium oxide doped thin film layer B40 on the hafnium oxide doped thin film layer A30 .

[0063] In the doped hafnium oxide superlattice thin film structure in the present application, the doped hafnium oxide thin film layer B40 is located on the side of the doped hafnium oxide thin film layer A30 away from the substrate 10 and is in contact with the doped hafnium oxide thin film layer A30. Therefore, after the doped hafnium oxide thin film layer A30 is formed, the doped hafnium oxide thin film layer A30 is in contact with the doped hafnium oxide thin film layer B40.

[0064] For example, a doped hafnium oxide-based material (such as Hf) having ferroelectricity but different from the doped hafnium oxide film layer A30 is deposited on the doped hafnium oxide film layer A30 by any thin film forming method (such as magnetron sputtering, evaporation, chemical vapor deposition, physical vapor deposition or atomic layer deposition). x Zr 1-x O2、Hf x Si 1-x O2、Hf x La 1-x O2、Hf x Al 1-x O2、Hf x Y 1-x O2, etc.) to form a doped hafnium oxide thin film layer B40.

[0065] In step 205, steps 203 and 204 are repeatedly and alternately performed on the hafnium oxide doped thin film layer B40, that is, the hafnium oxide doped thin film layer A and the hafnium oxide doped thin film layer B are alternately stacked to obtain a hafnium oxide doped superlattice thin film.

[0066] Next, the superior ferroelectric properties of the hafnium oxide-based superlattice thin film structure provided by the embodiment of the present application are introduced.

[0067] Figure 3 The high-resolution X-ray diffraction (XRD) pattern of the hafnium oxide-based superlattice film provided in the embodiment of the present application is shown. 0.5 Zr 0.5 O2(HZO) / Hf 0.95 La 0.05 O2(HLO) superlattice film as an example ( Figure 3A), a significant characteristic peak is detected near 30°, corresponding to the ferroelectric orthorhombic phase. For comparison, Figure 3 B shows the XRD pattern of an HZO monolayer film of the same thickness (about 8 nm). The experimental results show that the orthorhombic diffraction peak of the HZO / HLO superlattice film is more intense and sharper, indicating that its crystallinity is significantly better than that of a single-layer HZO film.

[0068] Further analysis of the XRD rocking curve (Table 1) shows that the full width at half maximum (FWHM) of the HZO and HZO / HLO films are 0.10° and 0.06°, respectively. This difference confirms the stabilizing effect of the superlattice structure on the ferroelectric orthorhombic phase, effectively suppressing the formation of the non-ferroelectric phase. As shown in Table 1, the remanent polarization value (P) of the HZO / HLO superlattice film provided in the embodiment of the present application is 0.10° and 0.06°, respectively. r ) reaches 52μC / cm 2 , significantly higher than the 15μC / cm of a single-layer HZO film. 2 , which is the highest value reported so far in epitaxial hafnium oxide-based films. In addition, the HZO / HLO superlattice film shows negligible wake-up effect and 9 The ferroelectric properties are kept stable in the durability test of multiple cycles ( Figure 4 ), fully meeting the application requirements of high-reliability memory.

[0069] Table 1

[0070]

[0071] The ferroelectric properties of hafnium oxide-based films usually decay with increasing thickness, mainly due to the competitive growth of non-ferroelectric phases. When the film thickness exceeds 10nm, the proportion of non-ferroelectric phases such as monoclinic or tetragonal phases increases significantly, resulting in a sharp decrease in the remanent polarization value (for example, when the thickness is greater than 30nm, P r Typically less than 10μC / cm 2 The hafnium oxide doped superlattice film structure provided in the present application effectively solves this problem. Taking the HZO / HLO superlattice film with a thickness of about 120nm as an example ( Figure 5 ), its residual polarization value can still reach 20μC / cm 2, breaking the thickness limit of traditional hafnium oxide-based films. This has important value for the application of ferroelectric films. For example, in energy harvesting devices, thicker ferroelectric films can produce higher voltages and charge densities, thereby improving energy conversion efficiency. This is particularly beneficial in piezoelectric energy harvesters, as thicker films can generate greater electrical output through mechanical vibration or strain. Furthermore, in applications requiring high power handling capabilities, thicker ferroelectric films can withstand higher voltages and provide better breakdown strength. This property is crucial for devices such as actuators, transducers, and high-power switches.

[0072] This embodiment provides a ferroelectric random access memory (FeRAM), such as Figure 6 As shown in FIG. 1 , a typical example of a basic storage element (acting as a capacitor in FeRAM) is shown. The structure within the dotted brackets shows the basic storage element of FeRAM, which consists of a top electrode layer of the substrate, a ferroelectric layer, and a bottom electrode layer. The readout signal is the resulting current or voltage change, providing information about the stored data. The ferroelectric layer is a doped hafnium oxide superlattice film provided in the embodiment of the present application. x A 1-x O2 / Hf x B 1-x O2 (A and B can be elements such as Zr, Si, La, Al, Y, Gd, Sr, and Ce). By applying an external electric field, the ferroelectric polarization of the ferroelectric layer switches between two stable states (commonly referred to as "0" and "1"), enabling non-volatile data storage. The ability to maintain its polarization state even after the electric field is removed enables this type of FeRAM to retain stored data for a long time.

[0073] This embodiment also provides a ferroelectric field effect transistor (FeFET), such as Figure 7 As shown in FIG. 1 , a typical example of a 1-transistor unit (acting as a capacitor in a FeFET) is shown. The structure within the dotted brackets shows the basic storage element of the FeFET, which consists of a top word line electrode (gate electrode), a ferroelectric layer, and an interface layer. The ferroelectric layer is a doped hafnium oxide superlattice film provided in an embodiment of the present application. x A 1-x O2 / Hf x B 1-x O2 (A and B can be elements such as Zr, Si, La, Al, Y, Gd, Sr, and Ce). By applying an external electric field, the ferroelectric polarization of the ferroelectric layer switches between two stable states (commonly referred to as "0" and "1"). This polarization state corresponds to the data stored in the FeFET. Because the polarization state remains stable in the absence of an electric field, the FeFET's non-volatile memory function is ensured. The polarization state of the ferroelectric layer influences the threshold voltage of the FeFET, thereby sensing the stored information.

[0074] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, characterized in that: The invention comprises a bottom electrode layer (20), a doped hafnium oxide thin film layer A (30), and a doped hafnium oxide thin film layer B (40) arranged in sequence in a direction perpendicular to a substrate (10), wherein the doped hafnium oxide thin film A (30) and the doped hafnium oxide thin film layer B (40) are in an alternating stacking structure (50), a doped hafnium oxide thin film stop layer A (60), and a doped hafnium oxide thin film stop layer B (70); The first layer of the doped hafnium oxide thin film layer A (30) is doped with hafnium metal oxide-Hf x A 1-x O2, hafnium metal oxide-Hf doped with element B in the second hafnium oxide doped thin film layer B (40) x B 1-x O2; The element A or the element B is selected from the group consisting of zirconium, silicon, lanthanum, aluminum, yttrium, gadolinium, strontium, manganese, and cerium, and is not the same element; and x ranges from 0.5 to 0.

99.

2. The superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to claim 1, characterized in that: Each of the doped hafnium oxide thin film layers A (30) has a thickness of at least 0.5 nm.

3. The superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to claim 1, characterized in that: Each of the doped hafnium oxide thin film layers B (40) has a thickness of at least 0.5 nm.

4. A method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film, characterized in that: The following steps are involved: providing a substrate (10); forming a bottom electrode layer (20) on the substrate (10); A superlattice structure is grown layer by layer on the bottom electrode layer (20), wherein the growth steps alternate between a first hafnium oxide doped thin film layer A (30) and a second hafnium oxide doped thin film layer B (40), thereby providing a stable ferroelectric phase within the superlattice structure.

5. The method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to claim 4, characterized in that: The substrate (10) is one of SrTiO3, Nb-SrTiO3, LSAT, DyScO3, NdScO3, TbScO3, LaAlO3, NdGaO3, YAlO3, SrLaAlO4 or Si, Si / SiO2.

6. The method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to any one of claims 4 to 5, characterized in that: The substrate (10) is an oriented single crystal substrate.

7. The method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to any one of claims 4 to 5, characterized in that: The growth step is performed by pulsed laser deposition, magnetron sputtering, atomic layer deposition or chemical vapor deposition.

8. The method for preparing a superlattice ferroelectric enhancement structure in a hafnium oxide-based thin film according to claim 7, characterized in that: For the pulsed laser deposition method, pulsed layer deposition is performed at approximately 800° C. using an excimer laser with a wavelength of 248 nm.

9. A ferroelectric random access memory cell comprising: top electrode layer; oriented single crystal substrate; and the superlattice ferroelectric enhancement structure and bottom electrode layer according to any one of claims 1 to 5.

10. A ferroelectric field effect transistor unit, comprising: a gate electrode layer; Interface layer; and the superlattice ferroelectric enhancement structure according to any one of claims 1 to 5.

Images