CN111554568A - Preparation method of hafnium oxide based ferroelectric film - Google Patents
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- 229910000449 hafnium oxide Inorganic materials 0.000 title claims abstract description 93
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/49—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET
- H01L29/51—Insulating materials associated therewith
- H01L29/516—Insulating materials associated therewith with at least one ferroelectric layer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/02521—Materials
- H01L21/02565—Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02656—Special treatments
- H01L21/02664—Aftertreatments
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Abstract
A method for preparing a hafnium oxide based ferroelectric thin film comprises the following steps: depositing a hafnium oxide-based film on a substrate; after a covering layer is deposited on the upper surface of the hafnium oxide base film, annealing treatment is carried out under the action of an electric field based on an annealing device, so as to obtain the crystalline large-area single-phase hafnium oxide base ferroelectric film, and the selective application of the electric field in different time periods of the annealing treatment is included; the annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction. The energy field in the crystallization process of the hafnium oxide-based ferroelectric film is controlled by applying an electric field while annealing the hafnium oxide-based ferroelectric film, so that the quality of the film is improved, and the hafnium oxide-based ferroelectric film has a large-area orthogonal phase and strong ferroelectricity; when the area of the film is reduced, better uniformity can be maintained.
Description
Technical Field
The invention relates to the technical field of ferroelectric films, in particular to a preparation method of a hafnium oxide based ferroelectric film.
Background
The ferroelectric memory has the advantages of high-speed reading and writing, low power consumption, high retentivity and the like, is called as one of the most potential next-generation novel memories, and the performance of the ferroelectric memory depends on the properties of the ferroelectric thin film to a great extent. The doped hafnium oxide thin film is verified to have ferroelectricity after 2011, and the compatibility problem of the traditional ferroelectric thin film complementary metal-oxide-semiconductor (CMOS) preparation process is solved. In addition, since the hafnium oxide thin film still has ferroelectricity when the thickness dimension is reduced to sub-ten nanometers, and has the advantages of large coercive electric field, large ferroelectric polarization, and the like, the memory device based on the hafnium oxide-based ferroelectric thin film has been developed in many breakthrough in recent years.
Ferroelectric fin-type transistors (Fe-finfets) based on 28nm process nodes have been fabricated and implemented for memory performance; ferroelectric memory devices of a three-dimensional NAND structure were also verified to be successful. With the continuous development of CMOS technology, in order to meet the requirements of the current advanced 5nm and 3nm process nodes, the ferroelectric thin films in the Fin gate structure and the nanowire gate structure are required to have excellent uniformity under small size in the structural design of the device.
However, the hafnium oxide-based ferroelectric thin films prepared at present all have the characteristic of coexistence of multiple phases, i.e., orthorhombic, monoclinic, tetragonal, and cubic phases. Simulation and experiment data show that when the size of a device channel is reduced to be below 30nm, the multi-phase coexistence characteristic of the device channel influences the uniformity of the device performance, including indexes such as on-state current, on-off ratio, threshold voltage and sub-threshold swing. How to improve the crystal phase uniformity of the hafnium oxide-based thin film in a small area is the most effective method for solving the bottleneck problem.
The hafnium oxide crystal has three stable phase structures under normal pressure, namely a monoclinic phase P21/c which exists stably at normal temperature, a tetragonal phase P42/nmc at the temperature of higher than 1720 ℃ and a cubic phase Fm3m at the temperature of higher than 2600 ℃. Research shows that the ferroelectric hafnium oxide is in an orthorhombic phase Pca21, also called as a ferroelectric phase of the material, and is generally formed as a transition phase in the interconversion of monoclinic phase, tetragonal phase and cubic phase in the annealing and crystallization process of the amorphous film, and can be stabilized by doping, oxygen vacancy control, electrode stress clamping and the like.
In the prior art, in the annealing process of the ferroelectric film, energy barrier differences formed by crystalline phases (including orthorhombic phase/ferroelectric phase, monoclinic phase, tetragonal phase and cubic phase) after crystallization are small, the hafnium oxide-based film prepared by physical vapor deposition or chemical vapor deposition at present has the characteristic of multiphase coexistence, and the sizes of the phases are about-several nanometers to tens of nanometers and are distributed unevenly, so that ferroelectric property in the film is uneven; as device dimensions gradually decrease, the non-uniformity of the performance of the hafnium oxide-based thin film will cause the non-uniformity of the device performance, thereby affecting the practical application and industrialization development of the device.
How to further optimize the preparation process and eliminate the multi-phase coexistence (inhibiting or even eliminating the non-ferroelectric phase) is a direction for improving the performance uniformity of the ferroelectric film when the device is miniaturized, and will bring breakthrough on process nodes for device integration of the hafnium oxide based film.
Disclosure of Invention
Objects of the invention
The invention aims to provide a preparation method of a hafnium oxide-based ferroelectric film, which controls an energy field in the crystallization process of the hafnium oxide-based ferroelectric film by applying an electric field while annealing the hafnium oxide-based ferroelectric film so as to enable the doped hafnium oxide film to have good ferroelectricity.
(II) technical scheme
In order to solve the above problems, according to one aspect of the present invention, there is provided a method for preparing a hafnium oxide based ferroelectric thin film, comprising: depositing a hafnium oxide-based film on a substrate; annealing treatment is carried out under the action of an electric field based on an annealing device to obtain a crystalline hafnium oxide based ferroelectric film, and the steps of selectively applying the electric field in different time periods of the annealing treatment and a time period before the annealing treatment are included; the annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction.
Further, before the annealing treatment under the action of the electric field, the method further comprises the following steps: and (3) preprocessing the hafnium oxide base film by adopting an electric field.
Further, the annealing treatment under the action of the electric field comprises the following steps: intermittently applying an electric field for three different periods of the annealing process and for a period of time prior to the annealing; or applying the electric field without interruption for three different periods of the annealing process and for a period of time prior to annealing.
Further, the electric field is direct current or alternating current or a combination of the two.
Further, depositing the hafnium oxide based thin film on the substrate further comprises: and depositing a covering layer on the upper surface of the hafnium oxide base film.
Further, the annealing temperature is as follows: 300 ℃ and 1000 ℃; the annealing time is as follows: 1s-1 h.
Further, the annealing device comprises: a housing; the annealing furnace supporting plate is arranged in the shell; the electric field lower polar plate and the electric field upper polar plate are arranged on the annealing furnace supporting plate in parallel, and a certain distance is preset between the electric field lower polar plate and the electric field upper polar plate so as to place the hafnium oxide-based thin film; heating means surrounding an inner wall surface of the case for heating the hafnium oxide-based thin film; and the voltage controller is electrically connected with the electric field upper polar plate, and the electric field lower polar plate is electrically connected with the grounding end so as to form an electric field in a preset distance between the electric field lower polar plate and the electric field upper polar plate.
Further, the deposition method is sputtering, atomic layer deposition, pulsed laser deposition, molecular beam epitaxy, ion beam epitaxy or chemical vapor deposition.
Further, the deposition temperature is lower than the crystallization temperature of the hafnium oxide based ferroelectric thin film.
(III) advantageous effects
The technical scheme of the invention has the following beneficial technical effects:
the quality of the hafnium oxide-based ferroelectric film is improved, so that the prepared hafnium oxide-based ferroelectric film has a large-area orthorhombic phase and strong ferroelectricity; and when the area of the film is reduced, the film performance also keeps better uniformity.
The preparation method can optimize the hafnium oxide-based film deposited by the conventional method, does not limit the doping element types and the amorphous film deposition method, does not limit the structure and the figure of the device (namely, the planar and 3D complex structures are both applicable), and greatly widens the application range.
Drawings
FIG. 1 is a schematic structural diagram of an annealing apparatus according to a first embodiment of the present invention;
FIG. 2 is a schematic structural view of an annealing furnace supporting plate of the annealing apparatus according to the first embodiment of the present invention;
FIG. 3 is a schematic structural diagram of an upper electric field plate of an annealing apparatus according to a first embodiment of the present invention;
FIG. 4 is a time temperature program diagram of a first embodiment of the present invention;
fig. 5 is a time electric field program diagram according to a first embodiment of the present invention.
Reference numerals:
1-annealing furnace supporting plate; 2-lower polar plate of electric field; 3-hafnium oxide based thin films; 4-ground terminal; 6-a voltage controller; 7-spacing; 8-heating equipment; 9-a temperature sensor; 10-shell.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
In the drawings a schematic view of a layer structure according to an embodiment of the invention is shown. The figures are not drawn to scale and certain details may be omitted. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.
It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The first embodiment is as follows:
the preparation method of the hafnium oxide based ferroelectric film provided by the embodiment of the invention comprises the following steps:
step S1: and depositing a hafnium oxide-based film on the substrate.
Specifically, a substrate is selected, and the substrate material may be a semiconductor material, such as silicon, germanium, gallium arsenide, gallium nitride, gallium oxide, etc., according to the device design requirements; or metal electrodes such as titanium nitride, tantalum nitride, tungsten, platinum, iridium, yttrium oxide; or a dielectric material such as hafnium oxide, zirconium oxide, silicon oxide, aluminum oxide, lanthanum oxide, hafnium nitride, silicon nitride, etc.
After the substrate is selected, the hafnium oxide base film is deposited, and the deposition method comprises the following steps: sputtering, atomic layer deposition, pulsed laser deposition, molecular beam epitaxy, ion beam epitaxy, chemical vapor deposition, and the like.
Meanwhile, the deposition temperature is not higher than the crystallization temperature of the hafnium oxide-based thin film. The crystallization temperature is the characteristic of the material, and different crystal phases of the same material have different crystallization temperatures; the annealing temperature is a temperature set by an actual process and may be higher/equal/lower than the crystallization temperature of the material. The annealing temperature is typically set to the crystallization temperature of the desired crystalline phase. If the temperature is too high in the process of depositing the hafnium oxide-based thin film, the hafnium oxide-based thin film is subjected to in-situ crystallization forming, which is equivalent to simultaneous annealing, and the subsequent electric field annealing cannot achieve the ideal effect.
Optionally, the deposited hafnium oxide-based thin film is a pure hafnium oxide thin film or a hafnium oxide-based thin film doped with other elements, wherein the doped other elements are: zr, Si, Al, La, Y, N, Gd, Sr, Ce, Fe, Sc, Ge, Lu, Ta, etc.
Step S2: and continuously depositing a covering layer on the upper surface of the hafnium oxide base film.
Specifically, the constituent material of the cap layer includes a deposition metal such as metal electrode titanium nitride, tantalum nitride, tungsten, platinum, iridium, yttrium oxide; or a dielectric material such as hafnium oxide, zirconium oxide, silicon oxide, aluminum oxide, lanthanum oxide, hafnium nitride, silicon nitride, etc.
The capping layer may form a certain stress effect and oxygen vacancy regulating effect in the hafnium oxide based ferroelectric thin film, both of which are advantageous for inducing the formation of the ferroelectric phase and stabilizing the formed ferroelectric phase. The ferroelectric phase can also be formed without applying a capping layer, but the final properties are generally inferior to those of the capping layer.
Step S3: based on annealing device, annealing treatment is carried out under the action of electric field, and the crystallized hafnium oxide-based ferroelectric film is obtained.
Optionally, the annealing temperature is: 300-1000 ℃, the annealing time is as follows: 1s-1 h.
Optionally, the annealing method is rapid thermal annealing or laser annealing.
Specifically, the electric field is applied simultaneously with the annealing treatment.
The annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction. In the application, the electric field can be uninterruptedly applied in the three stages of temperature rising, temperature keeping and temperature lowering; the electric field can be applied only in the temperature rising stage; the electric field may be applied only during the temperature maintenance phase; the electric field can be applied only in the cooling stage; or applying an electric field in two stages of temperature rising and temperature keeping; the electric field can also be applied in two stages of temperature keeping and temperature reduction.
Optionally, the electric field is a direct current or an alternating current.
During the crystallization process, the hafnium oxide-based thin film undergoes three processes of nucleation-nucleation growth-nucleation merging into large grains, which all affect the final morphology of the hafnium oxide-based thin film. The formation of crystal nucleus, the growth of crystal nucleus and the combination of crystal nucleus into large crystal grain are realized based on three stages of temperature rising, temperature maintaining and temperature lowering. The electric field is applied at each of these three stages in order to influence the energy field inside the hafnium oxide based thin film.
When the temperature is gradually increased to the holding temperature, a large number of crystal nuclei are formed at this stage, that is, the process of crystal nucleus formation can be regulated by applying an electric field while increasing the temperature.
The temperature is maintained mainly for the growth and merging of crystal nuclei, and the applied electric field at this stage will affect the growth and merging of crystal nuclei, i.e., the size and number of crystal grains in the final film. The smaller the size, the greater the number, the better the uniformity of the film.
The temperature reduction is to reduce the temperature to below 50 ℃, and mainly the stability of the crystalline phase is realized in the temperature reduction process, because the ferroelectric phase is a metastable phase, and finally the formation of the crystalline phase after the temperature reduction is finished depends on the energy field state in the film at that time. The application of an electric field may aid in the formation and stabilization of more metastable phases.
Direct current causes defects or charge centers or ions to move in one direction, including charge centers of Hf, O, and other dopant atoms. The relative positions of the atoms determine the crystalline phase. The alternating current causes each defect or charge center or ion to move periodically, making its distribution more uniform.
In the process of applying the electric field, only alternating current can be adopted, or only direct current can be adopted, or the combination of direct current and alternating current can be adopted, namely, the direct current is adopted in the temperature rising stage, and the alternating current is adopted in the temperature maintaining stage.
Optionally, the electric field strength applied by the present application is related to the annealing temperature and the thickness of the deposited hafnium oxide based ferroelectric thin film. When the film thickness is reduced to sub-5 nm, the corresponding optimal electric field intensity and annealing temperature also need to be adjusted, the electric field intensity and the annealing temperature are generally increased, but the annealing temperature is still kept between 300 ℃ and 1000 ℃.
Optionally, the electric field strength is greater than 0MV/cm and less than the breakdown electric field of the hafnium oxide based thin film.
Specifically, when the thickness of the hafnium oxide-based thin film is greater than 10nm, the breakdown electric field is about 5MV/cm, and when the thickness of the hafnium oxide-based thin film is less than 10nm, the breakdown electric field is about 6 MV/cm.
Preferably, the electric field strength is most effective in the vicinity of the coercive electric field (0.5 to 2MV/cm) of the hafnium oxide-based ferroelectric thin film. The coercive electric field is the electric field when the ferroelectric polarization is reversed, and reflects the difficulty of polarization reversal.
Alternatively, the annealing treatment and the application of the electric field are performed in the same apparatus.
Referring to fig. 1, 2 and 3, specifically, the annealing apparatus of the present invention includes: a housing 10; and an annealing furnace support plate 1 disposed inside the casing 10, the annealing furnace support plate 1 being for supporting the hafnium oxide-based thin film 3. The electric field lower polar plate 2 and the electric field upper polar plate 5 are arranged on the annealing furnace supporting plate 1 in parallel, and a certain distance 7 is preset between the electric field lower polar plate 2 and the electric field upper polar plate 5 so as to place the hafnium oxide base film 3; the voltage controller 6 is electrically connected with the electric field upper polar plate 5 and is used for controlling and generating alternating current or direct current; the lower electric field plate 2 is electrically connected to the ground 4 to form an electric field in conjunction with the voltage controller 6 in the space 7 between the lower electric field plate 2 and the upper electric field plate 5.
A heating device 8 surrounding an inner wall surface of the case 10 for heating the hafnium oxide-based thin film; optionally, the heating device 8 is a tungsten lamp. The temperature of the annealing can be adjusted by the skilled person by controlling the heating device 8.
Optionally, a temperature sensor 9 is further disposed on the annealing furnace support plate 1 for detecting the annealing temperature and determining the annealing temperature more accurately. In this example, a Zr doped hafnium oxide ferroelectric thin film is deposited on a substrate by atomic layer deposition to a thickness of 10 nm.
Fig. 4 is a time-temperature program diagram of the first embodiment of the present invention, and fig. 5 is a time-electric-field program diagram of the first embodiment of the present invention.
Referring to fig. 4 and 5, the annealing process of the first embodiment includes three stages. When the annealing temperature is raised from 0 ℃ to 450 ℃, the required time is 10s, and the stage is a heating process, wherein a direct current of 0.7MV/cm is adopted. When the annealing temperature was kept at 450 ℃ for 60s, the temperature was maintained during this period by applying an alternating current of 1 MV/cm. When the annealing temperature is reduced from 450 ℃ to 0 ℃, the required time is 300s, and the stage is a cooling process, and no electric field is applied.
Example two:
the second embodiment of the invention provides a preparation method of a hafnium oxide based ferroelectric film, which comprises the following steps:
step S1: and depositing a hafnium oxide-based film on the substrate.
Step S2: and (3) preprocessing the hafnium oxide base film by adopting an electric field.
Step S3: annealing under the action of an electric field to obtain a crystalline hafnium oxide-based ferroelectric film, wherein the annealing comprises selectively applying the electric field at different time periods of the annealing; the annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction.
In step S3, an electric field is applied directly to the hafnium oxide-based thin film.
In this embodiment, a difference from the first embodiment is that a capping layer is not deposited on the hafnium oxide based thin film, and a pretreatment process for the hafnium oxide based thin film is added before the annealing process.
The pretreatment is that an electric field is applied to the hafnium oxide base film for a certain time before the annealing treatment is started, and the electric field is kept for a certain time, so that defects in the film can be uniformly dispersed or gathered on the upper surface and the lower surface, the electrostatic effect is eliminated, and the transient breakdown caused by sudden electric field force applied to the film during annealing crystallization is prevented. The pretreated film has more uniform internal defects and better crystallization uniformity.
One skilled in the art may not pre-treat the film as is practical.
Optionally, applying the electric field intermittently for a period of time prior to annealing; or applying the electric field without interruption for some period of time prior to annealing.
Example three:
the third embodiment of the present invention provides a method for preparing a hafnium oxide based ferroelectric thin film, which comprises the following steps:
step S1: and depositing a hafnium oxide-based film on the substrate.
Step S2: and (3) preprocessing the hafnium oxide base film by adopting an electric field.
Step S3: annealing treatment is carried out under the action of an electric field based on an annealing device to obtain a crystalline hafnium oxide based ferroelectric film, and the method comprises the steps of selectively applying the electric field in different time periods of the annealing treatment and a time period before the annealing treatment; the annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction.
In step S3, an electric field is applied to the hafnium oxide-based thin film in the presence of an inert gas.
The difference between this embodiment and the second embodiment is that the inert gas affects the process of applying the electric field.
In particular, the direct application of the electric field ensures that the electric field programmed is applied entirely to the annealed sample, i.e., at a setting of 1MV/cm, and then actually at 1 MV/cm. This effect can be achieved in only two cases: (a) only suitable for the sample covered with the metal electrode, the wire of the annealing device is connected with the covering metal layer of the sample, and all the voltages can be applied to the annealed sample; (b) the precision requirement of a part for controlling the distance in the equipment is high, and the quartz plate on the equipment is required to be tightly attached to the upper surface of the sample, so that no gap is formed.
When it is not guaranteed that there is no gap between the sample and the wire or metal plate to which the electric field is applied, an inert gas is included, the annealing atmosphere is an inert gas resistant to breakdown, and the electric field actually applied to the hafnium oxide sample is related to the programmed electric field, the type of inert gas, and the gap filling, considering the partial pressure of the gas at this time.
The invention aims to protect a preparation method of a hafnium oxide based ferroelectric film, which comprises the following steps: depositing a hafnium oxide-based film on a substrate; after a covering layer is deposited on the upper surface of the hafnium oxide base film, annealing treatment is carried out under the action of an electric field to obtain a large-area crystalline single-phase hafnium oxide base ferroelectric film, and the selective application of the electric field in different time periods of the annealing treatment is included; the annealing treatment comprises three different time periods of temperature rise, temperature maintenance and temperature reduction. The doped hafnium oxide film has good ferroelectricity by applying an electric field while annealing the hafnium oxide-based ferroelectric film and controlling the energy field in the crystallization process of the hafnium oxide-based ferroelectric film.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.
Claims (9)
1. A method for preparing a hafnium oxide based ferroelectric film is characterized by comprising the following steps:
depositing a hafnium oxide-based film on a substrate;
annealing treatment is carried out under the action of an electric field based on an annealing device to obtain a crystalline hafnium oxide-based ferroelectric film, and the selective application of the electric field is carried out at different time periods of the annealing treatment;
the annealing treatment comprises three different time periods of temperature rise, temperature holding and temperature reduction.
2. The method of claim 1, wherein the annealing under the electric field further comprises:
and preprocessing the hafnium oxide base film by adopting the electric field.
3. The method of claim 2, wherein the annealing under the electric field comprises:
applying an electric field intermittently during three different periods of the annealing process and for a period of time prior to annealing; or
The electric field is applied without interruption for three different periods of time during the annealing process and for a period of time prior to annealing.
4. The method of claim 1,
the electric field is direct current or alternating current or a combination of the two.
5. The method of claim 1, wherein depositing the hafnium oxide based thin film on the substrate further comprises:
and depositing a covering layer on the upper surface of the hafnium oxide-based film.
6. The method of claim 1,
the annealing temperature is as follows: 300 ℃ and 1000 ℃;
the annealing time is as follows: 1s-1 h.
7. The method of claim 1, wherein the annealing device comprises:
a housing (10); and
an annealing furnace support plate (1), the annealing furnace support plate (1) being disposed within the housing (10);
the electric field lower polar plate (2) and the electric field upper polar plate (5) are arranged on the annealing furnace supporting plate (1) in parallel, and a certain distance is preset between the electric field lower polar plate (2) and the electric field upper polar plate (5) for placing the hafnium oxide base film;
a heating device (8), the heating device (8) surrounding an inner wall surface of the case (10) for heating the hafnium oxide based thin film;
and the voltage controller (6), the voltage controller (6) is electrically connected with the electric field upper polar plate (5), the electric field lower polar plate (2) is electrically connected with the grounding end (4), so that an electric field is formed in a preset interval between the electric field lower polar plate (2) and the electric field upper polar plate (5).
8. The method of claim 1,
the deposition method is sputtering, atomic layer deposition, pulse laser deposition, molecular beam epitaxy, ion beam epitaxy or chemical vapor deposition.
9. The method of claim 1,
the deposition temperature is lower than the crystallization temperature of the hafnium oxide based ferroelectric thin film.
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