Hafnium-based ferroelectric film and preparation method and application thereof

Abstract

The invention belongs to the technical field of advanced storage, and particularly relates to a hafnium-based ferroelectric film and a preparation method and application thereof. The chemical formula of the hafnium-based ferroelectric film is HfxMyO2, x is 0.5-1, y is 0.5-1, and M is selected from Zr, Al or La. According to the hafnium-based ferroelectric film provided by the invention, the internal element doping is precisely regulated and controlled, so that the internal part of the hafnium-based ferroelectric film has enough stress in the growth process, and therefore, the hafnium-based ferroelectric film has stable ferroelectric performance without annealing, the technical defects of the annealing of the existing hafnium-based ferroelectric film are overcome, and a hafnium-based ferroelectric capacitor compatible in the later process is further obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of advanced storage technology, and more particularly to hafnium-based ferroelectric thin films, a preparation method and application thereof. BACKGROUND

[0002] The hafnium-based ferroelectric material is a material with simple composition elements, stable chemical properties and stable ferroelectric properties when the thickness is less than 3 nm. Due to these characteristics, the hafnium-based ferroelectric material exhibits significant competitive advantages.

[0003] In order to obtain stable ferroelectric properties, the hafnium-based ferroelectric thin film needs to apply sufficient stress to the external electrode during the annealing process. However, the hafnium-based ferroelectric material needs a high temperature, generally greater than 500 DEG C, during the annealing process, which causes the problem that it cannot be compatible with the subsequent process. Therefore, many subsequent processes cannot withstand such a high temperature, which limits the application of the hafnium-based ferroelectric material in the field of integrated circuits and microelectronic devices, and reduces the commercial feasibility thereof. SUMMARY

[0004] In view of the above-mentioned problems in the prior art, the application provides a hafnium-based ferroelectric thin film, a preparation method and a hafnium-based ferroelectric capacitor compatible with subsequent processes. The hafnium-based ferroelectric thin film provided by the application has a chemical formula of HfxMyO2, wherein x is 0.5-0.75, y is 0.5-1, and M is selected from Zr, Al or La. The hafnium-based ferroelectric thin film of the application has sufficient stress inside during the growth process through precise control of internal element doping, so that it has stable ferroelectric properties without annealing, overcomes the technical defects of the existing hafnium-based ferroelectric thin film annealing, and further obtains a hafnium-based ferroelectric capacitor compatible with subsequent processes.

[0005] Based on the above technical purposes, the application is implemented by using the following technical solutions: In a first aspect, the application protects a hafnium-based ferroelectric thin film. The hafnium-based ferroelectric thin film has a chemical formula of HfxMyO2, wherein x is 0.5-0.75, y is 0.5-1, and M is selected from Zr, Al or La.

[0006] Preferably, the stress of the hafnium-based ferroelectric thin film is 300 MPa-500 MPa.

[0007] Preferably, the hafnium-based ferroelectric thin film has a remanent polarization of 43 muC / cm2-52.3 muC / cm2, a dielectric constant of 23-28, and a piezoelectric coefficient of 42 pm / V-47 pm / V, and the hafnium-based ferroelectric thin film is close to polarization saturation at a low voltage of 2 V-2.5 V.

[0008] Preferably, the hafnium-based ferroelectric thin film is made of HfO2 and an oxide of M with a particle size of 2 nm-30 nm.

[0009] Preferably, the thickness of the hafnium-based ferroelectric thin film is 8-10 nm.

[0010] In a second aspect, the present application protects a method for preparing a hafnium-based ferroelectric thin film, comprising the following steps: Mixing HfO2 and the oxide of M according to the stoichiometric ratio of each element in HfxMyO2 to obtain a mixed powder.

[0011] After ball milling the mixed powder, calcine the mixed powder at a preset temperature of 500-600℃ and a preset calcination time of 60-180s to obtain a calcined mixed powder.

[0012] Using atomic layer deposition, deposit the calcined mixed powder at 250-370℃ by cyclic deposition to obtain the hafnium-based ferroelectric thin film.

[0013] In a third aspect, the present application provides a back-compatible hafnium-based ferroelectric capacitor, which is prepared using the hafnium-based ferroelectric thin film described above.

[0014] Preferably, the back-compatible hafnium-based ferroelectric capacitor is composed of a top electrode, a hafnium-based ferroelectric thin film, a metal layer and a substrate, which are sequentially stacked from top to bottom.

[0015] The back-compatible hafnium-based ferroelectric capacitor is prepared according to the following steps: Prepare a substrate.

[0016] Using magnetron sputtering, deposit a metal layer on the substrate and use the metal layer as a bottom electrode.

[0017] Using atomic layer deposition, deposit a hafnium-based ferroelectric thin film on the metal layer.

[0018] Using the Lift-off method or the hard mask method, physically vapor deposit a top electrode on the hafnium-based ferroelectric thin film.

[0019] Preferably, the metal of the metal layer is selected from TiN, TaN or W, and the thickness of the metal layer is 80-120 nm.

[0020] Preferably, the top electrode is selected from an aluminum-doped zinc oxide electrode.

[0021] Preferably, the substrate is a semiconductor substrate, and the semiconductor substrate is Si, Ge, SiC or a thin film semiconductor.

[0022] Compared with the prior art, the present application has the following beneficial effects: 1. The application provides a hafnium-based ferroelectric thin film with a chemical formula of HfxMyO2, wherein x is 0.5-0.75, y is 0.5-1, and M is selected from Zr, Al or La; the hafnium-based ferroelectric thin film is precisely controlled by internal element doping, so that sufficient stress is provided in the growth process, thereby obtaining stable ferroelectric properties without annealing, and the stress reaches 300-500 MPa.

[0023] 2. The application precisely controls internal element doping of the hafnium-based ferroelectric thin film by using an atomic layer deposition method, so that sufficient stress is provided in the growth process, thereby obtaining stable ferroelectric properties without annealing, and then a top electrode is prepared by using a Lift-off method or a hard mask method physical vapor deposition process, so as to realize preparation of a hafnium-based ferroelectric capacitor compatible with subsequent processes.

[0024] 3. The application utilizes an atomic layer deposition technology to precisely control the type and concentration of doping elements in hafnium oxide, so that sufficient stress can be provided in the crystallization process, thereby obtaining stable ferroelectric properties without annealing, and the growth cycle number of the hafnium-based ferroelectric thin film is precisely controlled to obtain hafnium-based ferroelectric thin films with different thicknesses, and finally a hafnium-based ferroelectric memory device is obtained based on the thin film.

[0025] 4. The preparation method of the application is simple, effective and does not require high-temperature thermal annealing, so that it can be compatible with subsequent processes. The thickness of the hafnium oxide thin film is precisely controlled by controlling the growth cycle number of the atomic layer deposition, so that large-area preparation of the hafnium-based ferroelectric thin film with controllable size can be realized.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the protection scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structure diagram of a hafnium-based ferroelectric capacitor compatible with subsequent processes of the application.

[0028] Explanation of reference signs: 1, substrate; 2, metal layer; 3, hafnium-based ferroelectric thin film; 4, top electrode. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in combination with examples, and it should be particularly noted that: in the following examples, the specific conditions are not specified, and the conventional conditions or the conditions recommended by the manufacturer are used, and in the following examples, the raw materials used can be obtained from ordinary market sales unless otherwise specified.

[0030] Considering the problem of prior art that "hafnium-based ferroelectric thin film needs to apply sufficient stress to external electrode in annealing process to obtain stable ferroelectric characteristics, however, hafnium-based ferroelectric material needs high temperature in annealing process, generally greater than 500 DEG C, which causes that it cannot be compatible with subsequent process", the present application is started from two aspects of hafnium-based ferroelectric thin film composition and preparation method to solve the defects existing in the prior art hafnium-based ferroelectric thin film.

[0031] As to the hafnium-based ferroelectric thin film composition, the present application provides a hafnium-based ferroelectric thin film with chemical formula HfxMyO2, wherein x is 0.5-0.75, y is 0.5-1, and M is selected from Zr, Al or La; the hafnium-based ferroelectric thin film of the present application has sufficient stress in the growth process by precise control of internal element doping, and has stable ferroelectric properties.

[0032] As to the preparation method of hafnium-based ferroelectric thin film, the present application uses the mixed powder after pre-sintering as raw material, and adopts atomic layer deposition method to obtain hafnium-based ferroelectric thin film, the temperature of atomic layer deposition method is 250 DEG C-370 DEG C, which is much lower than the annealing treatment of prior art greater than 500 DEG C, and overcomes the problem of not being compatible with subsequent process.

[0033] The technical scheme of the present application is further studied by using examples and comparative examples, and the specific research method and results are shown as follows: Example 1 A preparation method of hafnium-based ferroelectric thin film, the chemical formula of the hafnium-based ferroelectric thin film is Hf 0.5 ZrO2, the hafnium-based ferroelectric thin film is made of Hf 0.5 O2 and Zr doped oxide with a particle size of 10 nm, the thickness of the hafnium-based ferroelectric thin film is 10 nm, and the method comprises the following steps: S1, according to the stoichiometric ratio of each element in Hf 0.5 ZrO2, Hf 0.5 O2 and ZrO2 are mixed to obtain a mixed powder.

[0034] S2, the mixed powder is ball milled and calcined at a preset temperature of 500 DEG C for 60 s to obtain a mixed powder after pre-sintering.

[0035] S3, the mixed powder after pre-sintering is deposited by cycle deposition at 250 DEG C by atomic layer deposition method to obtain the hafnium-based ferroelectric thin film.

[0036] A preparation method of hafnium-based ferroelectric capacitor compatible with subsequent process, comprising the following steps: S1, preparing Si substrate.

[0037] S2, depositing a metal layer on the Si substrate by using a magnetron sputtering method, the deposition condition is: the radio frequency power is 200 W, the deposition rate is 15 nm / min, argon is used as the main gas, the flow rate is 30 sccm, the deposition is carried out at 500 ℃, the metal of the metal layer is TiN, and the thickness of the metal layer is 80 nm, and the metal layer is used as a bottom electrode.

[0038] S3, depositing a hafnium-based ferroelectric film on the metal layer by using an atomic layer deposition method; the deposition condition is: the deposition temperature is 250 ℃ under argon, the pressure is 26.6 Pa, the pulse of the mixed powder is 1 s, the pulse of the oxygen source is 1 s, and N2 is blown for 2 s after the deposition is completed.

[0039] S4, physically depositing a top electrode on the hafnium-based ferroelectric film by using a lift-off method, the top electrode is an aluminum-doped zinc oxide electrode, the deposition rate is 0.5 nm / s, the radio frequency power is 13.56 MHz, peeling is carried out after the deposition, the peeling solvent is N-methyl pyrrolidone, and the hafnium-based ferroelectric capacitor is immersed in the N-methyl pyrrolidone at 80 ℃ for 2 min.

[0040] The hafnium-based ferroelectric capacitor prepared in Example 1 is prepared by using an ALD method to prepare a Hf 0.5 ZrO2 film with a thickness of 10 nm on a Si substrate, using Hf 0.5 ZrO2 film as a ferroelectric barrier layer, selecting TiN and an aluminum-doped zinc oxide electrode as double-conductive electrodes, and inserting a Si layer therebetween, and constructing a Hf 0.5 O2-based ferroelectric tunnel junction. The tunnel junction exhibits a high resistance switching ratio of up to 850, an ultrafast write speed of 0.8 ns at a voltage of 5 V, a read current of 92 A / cm 2 2, and a retention characteristic of up to 105 s at 85 ℃.

[0041] Example 2 A preparation method of a hafnium-based ferroelectric film, the chemical formula of the hafnium-based ferroelectric film is Hf 0.5 Zr 0.5 O2, the hafnium-based ferroelectric film is made of a doped oxide of Hf 0.5 O2 and Zr with a particle size of 30 nm, the thickness of the hafnium-based ferroelectric film is 10 nm, and the preparation method comprises the following steps. S1, mixing Hf 0.5 Zr 0.5 O2 and ZrO2 according to the stoichiometric ratio of each element in Hf 0.5 O2 and ZrO2 to obtain a mixed powder.

[0042] S2, after the mixed powder is ball milled, the mixed powder is calcined at a preset temperature of 550 ℃ and for a preset calcination time of 90 s to obtain a calcined mixed powder.

[0043] S3, the mixed powder after pre-sintering is deposited by circulation at 300 DEG C to prepare hafnium-based ferroelectric film by atomic layer deposition method.

[0044] A preparation method of a backward compatible hafnium-based ferroelectric capacitor comprises the following steps: S1, preparing Si substrate.

[0045] S2, depositing metal layer on Si substrate by magnetron sputtering method, the deposition condition is: radio frequency power 200 W, deposition rate 15 nm / min, argon gas as main gas, flow rate 30 sccm, deposition at 500 DEG C, metal of metal layer is TiN, thickness of metal layer is 100 nm, and metal layer is bottom electrode.

[0046] S3, depositing hafnium-based ferroelectric film on metal layer by atomic layer deposition method, the deposition condition is: under argon gas, deposition temperature is 300 DEG C, pressure is 26.6 Pa, precursor pulse is 0.3 s, oxygen source pulse is 0.3 s, and N2 purging is 2 s.

[0047] S4, depositing top electrode on hafnium-based ferroelectric film by lift-off method, the top electrode is aluminum-doped zinc oxide electrode, deposition rate is 0.8 nm / s, radio frequency power is 13.56 MHz, and after deposition, stripping is carried out, stripping solvent is N-methyl pyrrolidone, and soaking in N-methyl pyrrolidone at 80 DEG C for 2 min.

[0048] The backward compatible hafnium-based ferroelectric capacitor prepared in example 2 is prepared by ALD method on Si substrate, and the thickness of Hf 0.5 Zr 0.5 O2 film is 10 nm, Hf 0.5 Zr 0.5 O2 film is used as ferroelectric barrier layer, TiN and aluminum-doped zinc oxide electrode double-conductive electrodes are selected and used, and Si layer is inserted in the electrodes, and Hf 0.5 O2-based ferroelectric tunnel junction is constructed. The tunnel junction exhibits a high resistance switching ratio of 850, an ultrafast write speed of 0.5 ns at 5 V voltage, a read current of 88 A / cm 2 2, and a retention characteristic of 110 s at 85 DEG C.

[0049] Example 3 A preparation method of hafnium-based ferroelectric film, the chemical formula of the hafnium-based ferroelectric film is Hf 0.5 LaO2, the hafnium-based ferroelectric film is made of Hf 0.5 O2 and La doped oxide with a particle size of 5 nm, the thickness of the hafnium-based ferroelectric film is 10 nm, and the method comprises the following steps: S1, according to Hf 0.5stoichiometric ratio of each element in LaO2, Hf 0.5 O2 and La-Mg-O are mixed to obtain a mixed powder.

[0050] S2, after the mixed powder is ball milled, the mixed powder is calcined at a preset temperature of 600 DEG C and a preset calcination time of 180 s to obtain a calcined mixed powder.

[0051] S3, the calcined mixed powder is deposited by circulation at 370 DEG C by an atomic layer deposition method to prepare a hafnium-based ferroelectric film.

[0052] A preparation method of a hafnium-based ferroelectric capacitor compatible with a back end of line, comprising the following steps: S1, a Si substrate is prepared.

[0053] S2, a metal layer is deposited on the Si substrate by a magnetron sputtering method, the deposition conditions are: a radio frequency power of 200 W, a deposition rate of 15 nm / min, argon gas is used as the main gas, the flow rate is 30 sccm, and the deposition is performed at 500 DEG C, the metal of the metal layer is TiN, the thickness of the metal layer is 80 nm, and the metal layer is used as a bottom electrode.

[0054] S3, a hafnium-based ferroelectric film is deposited on the metal layer by an atomic layer deposition method, the deposition conditions are: under argon gas, the deposition temperature is 370 DEG C, the pressure is 26.6 Pa, the precursor pulse is 1.5 s, the oxygen source pulse is 2 s, and N2 is purged for 3 s.

[0055] S4, a top electrode is physically vapor deposited on the hafnium-based ferroelectric film by a hard mask method, the top electrode is an aluminum-doped zinc oxide electrode, the deposition rate is 1.0 nm / s, the radio frequency power is 13.56 MHz, and after deposition, stripping is performed, the stripping solvent is N-methyl pyrrolidone, and the N-methyl pyrrolidone is soaked at 80 DEG C for 2 min.

[0056] The hafnium-based ferroelectric capacitor compatible with the back end of line prepared in Example 3 is prepared by an ALD method on a Si substrate to prepare a Hf 0.5 LaO2 film, Hf 0.5 LaO2 film is used as a ferroelectric barrier layer, TiN and an aluminum-doped zinc oxide electrode are selected as double-conductive electrodes, and a Si layer is inserted therebetween to construct a Hf 0.5 O2-based ferroelectric tunnel junction. The tunnel junction exhibits a high resistance switching ratio of up to 850, an ultrafast write speed of 0.7 ns at a voltage of 5 V, a read current of 85 A / cm 2 2, and a retention characteristic of up to 101 s at 85 DEG C.

[0057] Example 4 A preparation method of a hafnium-based ferroelectric film, the chemical formula of the hafnium-based ferroelectric film is Hf0.75 HfO2, hafnium-based ferroelectric thin film with a particle size of 2 nm 0.75 O2 and Al, the thickness of the hafnium-based ferroelectric thin film is 10 nm, comprising the following steps: S1, according to Hf 0.75 AlO2, the stoichiometric ratio of each element, Hf 0.75 O2 and Al2O3 are mixed to obtain a mixed powder.

[0058] S2, the mixed powder is ball milled and calcined at a preset temperature of 500℃ for 180s to obtain a calcined mixed powder.

[0059] S3, the calcined mixed powder is deposited by atomic layer deposition at 280℃ to prepare a hafnium-based ferroelectric thin film.

[0060] A preparation method of a back-compatible hafnium-based ferroelectric capacitor, comprising the following steps: S1, preparing a Si substrate.

[0061] S2, using a magnetron sputtering method to deposit a metal layer on the Si substrate, the deposition conditions are: radio frequency power 200W, deposition rate 15nm / min, argon gas as the main gas, flow rate 30sccm, deposition at 500℃, the metal of the metal layer is TiN, the thickness of the metal layer is 100nm, and the metal layer is used as the bottom electrode.

[0062] S3, using an atomic layer deposition method to deposit a hafnium-based ferroelectric thin film on the metal layer, the deposition conditions are: under argon, the deposition temperature is 280℃, the pressure is 26.6Pa, the precursor pulse is 0.8s, the oxygen source pulse is 1.5s, and N2 is purged for 3s.

[0063] S4, using a hard mask method to physically vapor deposit a top electrode on the hafnium-based ferroelectric thin film, the top electrode is an aluminum-doped zinc oxide electrode, the deposition rate is 0.5nm / s, the radio frequency power is 13.56MHz, and after deposition, stripping is performed, the stripping solvent is N-methyl pyrrolidone, and the N-methyl pyrrolidone is soaked at 80℃ for 2min.

[0064] The back-compatible hafnium-based ferroelectric capacitor prepared in Example 4 is prepared by using an ALD method on a Si substrate to prepare a Hf 0.75 AlO2 thin film, the Hf 0.75 AlO2 thin film as a ferroelectric barrier layer, TiN and aluminum-doped zinc oxide electrodes are selected as double-conductive electrodes, and a Si layer is inserted therebetween to construct a Hf 0.75 O2-based ferroelectric tunnel junction. The tunnel junction exhibits a high resistance switching ratio of 800, an ultrafast write speed of 0.3ns at a voltage of 5V, and a current density of 80A / cm2 a read current of 0.5mA and a retention characteristic at 85℃ for 98s.

[0065] Embodiment 5 The application discloses a preparation method of a hafnium-based ferroelectric film, and the hafnium-based ferroelectric film has a chemical formula of HfAlO2 and is made of doped oxides of HfO2 and Al with a particle size of 8 nm, and the hafnium-based ferroelectric film has a thickness of 8 nm, and the preparation method comprises the following steps: S1, mixing HfO2 and Al2O3 according to the stoichiometric ratio of each element in HfAlO2 to obtain a mixed powder.

[0066] S2, ball milling the mixed powder and then calcining the mixed powder under a preset temperature of 600 DEG C and a preset calcining time of 60 s to obtain a calcined mixed powder.

[0067] S3, depositing the calcined mixed powder by circulation at 320 DEG C by using an atomic layer deposition method to obtain the hafnium-based ferroelectric film.

[0068] A preparation method of a hafnium-based ferroelectric capacitor compatible with a back-end process, comprising the following steps: S1, preparing a Si substrate.

[0069] S2, depositing a metal layer on the Si substrate by using a magnetron sputtering method, and the deposition conditions are as follows: a radio frequency power of 200 W, a deposition speed of 15 nm / min, argon gas as a main gas with a flow rate of 30 sccm, and deposition at 500 DEG C, the metal of the metal layer is TiN, the thickness of the metal layer is 120 nm, and the metal layer is used as a bottom electrode.

[0070] S3, depositing a hafnium-based ferroelectric film on the metal layer by using an atomic layer deposition method, and the deposition conditions are as follows: under argon gas, a deposition temperature of 320 DEG C, a pressure of 26.6 Pa, a precursor pulse of 0.5 s, an oxygen source pulse of 0.8 s, and N2 blowing for 3 s.

[0071] S4, depositing a top electrode on the hafnium-based ferroelectric film by using a hard mask method, the top electrode is an aluminum-doped zinc oxide electrode, the deposition rate is 0.5 nm / s, the radio frequency power is 13.56 MHz, and after deposition, stripping is performed, the stripping solvent is N-methyl pyrrolidone, and the hafnium-based ferroelectric film is soaked in the N-methyl pyrrolidone at 80 DEG C for 2 min.

[0072] The back-compatible hafnium-based ferroelectric capacitor prepared in Example 5 uses an ALD method to prepare a HfAlO2 film with a thickness of 8 nm on a Si substrate, uses the HfAlO2 film as a ferroelectric barrier layer, selects a TiN and aluminum-doped zinc oxide electrode double-conductive electrode, and inserts a Si layer therein to construct a HfO2-based ferroelectric tunnel junction. The tunnel junction exhibits a high resistance switching ratio of 820, an ultrafast write speed of 0.5 ns at a voltage of 5 V, a read current of 82 A / cm2, and a retention characteristic of up to 101s at 85℃. 2

[0073] Comparative Example 1 A method for preparing a hafnium-based ferroelectric capacitor is the same as the preparation steps of Example 1, except that the hafnium-based ferroelectric film with the chemical formula Hf 0.5 ZrO2 is replaced by hafnium oxide HfO2.

[0074] Comparative Example 2 A method for preparing a hafnium-based ferroelectric capacitor is the same as the preparation steps of Example 1, except that both the bottom electrode and the top electrode are replaced by zinc oxide without doping.

[0075] Compared with Comparative Examples 1 and 2, Example 1 has excellent CMOS process compatibility, maintains stable ferroelectricity at a nanoscale, can be micronized to a thickness of less than 3 nm, has an ultrafast flipping speed and a low operating voltage, and has low-temperature environmental adaptability. Based on this, the hafnium-based ferroelectric capacitor prepared in Comparative Examples 1 and 2 has poorer performance than the back-compatible hafnium-based ferroelectric capacitor of Example 1, and the polarization strength of the hafnium-based ferroelectric capacitor of Comparative Examples 1 and 2 is much lower than that of the back-compatible hafnium-based ferroelectric capacitor of Example 1.

[0076] The above merely illustrates specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and should be encompassed within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. A hafnium-based ferroelectric thin film, characterized by, The chemical formula of the hafnium-based ferroelectric thin film is HfxMyO2, wherein x is 0.5-0.75, y is 0.5-1, and M is selected from Zr, Al or La.

2. The hafnium-based ferroelectric thin film of claim 1, wherein, The hafnium-based ferroelectric thin film has a thickness of 8-10 nm.

3. A method of producing the hafnium-based ferroelectric thin film according to any one of claims 1 to 2, characterized by, The method comprises the following steps: HfO2 and oxides of M are mixed according to the stoichiometric ratio of each element in HfxMyO2 to obtain a mixed powder; The mixed powder is ball milled and then calcined at a preset temperature of 500-600 DEG C for a preset time of 60-180 s to obtain a pre-fired mixed powder; The pre-fired mixed powder is deposited by circulation at 250-370 DEG C by an atomic layer deposition method to obtain the hafnium-based ferroelectric thin film.

4. A back-compatible hafnium-based ferroelectric capacitor, characterized by, The hafnium-based ferroelectric thin film is prepared by the method.

5. The back-compatible hafnium-based ferroelectric capacitor of claim 4, wherein, The back-compatible hafnium-based ferroelectric capacitor is composed of a top electrode, a hafnium-based ferroelectric thin film, a metal layer and a substrate which are sequentially stacked from top to bottom. The back-compatible hafnium-based ferroelectric capacitor is prepared according to the following steps: A substrate is prepared; A metal layer is deposited on the substrate by a magnetron sputtering method, and the metal layer is used as a bottom electrode; The hafnium-based ferroelectric thin film is deposited on the metal layer by an atomic layer deposition method; The top electrode is physically vapor deposited on the hafnium-based ferroelectric thin film by a Lift-off method or a hard mask method.

6. The back-compatible hafnium-based ferroelectric capacitor of claim 5, wherein, The metal of the metal layer is selected from TiN, TaN or W.

7. The back-compatible hafnium-based ferroelectric capacitor of claim 6, wherein, The thickness of the metal layer is 80-120 nm.

8. The back-compatible hafnium-based ferroelectric capacitor of claim 5, wherein, The top electrode is selected from an aluminum-doped zinc oxide electrode.

9. The back-compatible hafnium-based ferroelectric capacitor of claim 5, wherein, The substrate is a semiconductor substrate.

10. The back-compatible hafnium-based ferroelectric capacitor of claim 9, wherein, The semiconductor substrate is Si, Ge, SiC or a thin film semiconductor.

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